阅读说明：本技术 热电模块及包括其的冰箱 (Thermoelectric module and refrigerator comprising same ) 是由 尹皙俊 林亨根 李政勋 李镐碝 于 2020-03-25 设计创作，主要内容包括：根据本发明的实施例的热电模块,其可以包括：冷侧散热器；热电元件,其吸热面结合于所述冷侧散热器；热侧散热器,其结合于所述热电元件的发热面,并且将从所述冷侧散热器传递的热量释放到所述热电元件的外部；以及密封盖,其使所述冷侧散热器的边缘和所述热侧散热器的边缘连接并包围所述热电元件,所述冷侧散热器、热侧散热器以及热电元件可以通过所述密封盖构成一体型。另外,所述热电元件可以是由具有相同或不同的规格的两个热电元件结合的级联式热电元件。(A thermoelectric module according to an embodiment of the present invention may include: a cold side heat sink; a thermoelectric element having a heat absorbing surface coupled to the cold-side heat sink; a hot-side heat sink coupled to a heat emitting surface of the thermoelectric element and releasing heat transferred from the cold-side heat sink to the outside of the thermoelectric element; and a sealing cover which connects an edge of the cold-side heat sink and an edge of the hot-side heat sink and surrounds the thermoelectric element, wherein the cold-side heat sink, the hot-side heat sink, and the thermoelectric element may be integrally formed by the sealing cover. In addition, the thermoelectric element may be a cascade type thermoelectric element in which two thermoelectric elements having the same or different specifications are combined.)

1. A thermoelectric module, comprising:

a cold side heat sink;

a thermoelectric element having a heat absorbing surface bonded to the cold-side heat sink;

a hot-side heat sink coupled to a heat emitting surface of the thermoelectric element and releasing heat transferred from the cold-side heat sink to the outside of the thermoelectric element; and

and a sealing cover connecting an edge of the cold-side heat sink and an edge of the hot-side heat sink and surrounding the thermoelectric element.

2. The thermoelectric module of claim 1,

the thermoelectric element includes:

a semiconductor element section including a P-type semiconductor and an N-type semiconductor;

a heat absorption side electrode portion formed at one end of the semiconductor element portion; and

and a heat-generating-side electrode portion formed at the other end of the semiconductor element portion.

3. The thermoelectric module of claim 2,

further comprising a heat sink bonded to an end portion of the semiconductor element portion,

the electrode portion of the semiconductor element portion is soldered to the heat sink.

4. The thermoelectric module of claim 3,

the thermoelectric element includes:

a first thermoelectric element having a heat absorbing surface bonded to the cold-side heat sink side; and

a second thermoelectric element having a heat generating surface coupled to the hot-side heat sink,

the heat generating surface of the first thermoelectric element and the heat absorbing surface of the second thermoelectric element are connected so as to be capable of heat transfer.

5. The thermoelectric module of claim 4,

further comprising a heat transfer block interposed between the joining portions of the first thermoelectric element and the second thermoelectric element,

the heat absorption side electrode of the first thermoelectric element is attached to the cold side heat sink,

the heat generation-side electrode of the second thermoelectric element is attached to the hot-side heat sink,

the heat-generating-side electrode of the first thermoelectric element is attached to one surface of the heat transfer block,

the heat absorption-side electrode of the second thermoelectric element is attached to the other surface of the heat transfer block.

6. The thermoelectric module of claim 4,

the heat transfer block is a metal block made of a non-electrically conductive material including aluminum.

7. The thermoelectric module of claim 5,

the thermoelectric module further comprises heat transfer blocks which are respectively clamped between the cold side radiator and the joint part of the first thermoelectric element and between the hot side radiator and the joint part of the second thermoelectric element.

8. The thermoelectric module of claim 4,

applying any one of a high voltage, a medium voltage lower than the high voltage, and a low voltage lower than the medium voltage to the first thermoelectric element and the second thermoelectric element,

the magnitude of the voltage applied to the first thermoelectric element and the magnitude of the voltage applied to the second thermoelectric element are different.

9. The thermoelectric module of claim 8,

the voltage applied to the second thermoelectric element is greater than the voltage applied to the first thermoelectric element.

10. The thermoelectric module of claim 9,

when the voltage applied to the second thermoelectric element is a high voltage, the voltage applied to the first thermoelectric element is a medium voltage or a low voltage.

11. The thermoelectric module of claim 9,

when the voltage applied to the second thermoelectric element is a medium voltage, the voltage applied to the first thermoelectric element is a low voltage.

12. The thermoelectric module of claim 4,

the temperature difference (Δ T1) between the heat absorbing surface and the heat generating surface of the first thermoelectric element is set to be the same as the temperature difference (Δ T2) between the heat absorbing surface and the heat generating surface of the second thermoelectric element.

13. The thermoelectric module of claim 4,

a temperature difference (DeltaT 1) between the heat absorbing surface and the heat generating surface of the first thermoelectric element is set to be larger than a temperature difference (DeltaT 2) between the heat absorbing surface and the heat generating surface of the second thermoelectric element.

14. The thermoelectric module of claim 1,

the cold-side heat sink comprises a heat conductor provided with a plurality of heat exchange fins,

the hot-side radiator includes a heat conductor having a plurality of heat exchange fins or an evaporator for flowing a low-temperature refrigerant.

15. A thermoelectric module, comprising:

a cold side heat sink;

a first thermoelectric element having a heat absorbing surface thermally conductively coupled to the cold-side heat sink;

a second thermoelectric element having a heat absorbing surface thermally conductively coupled to a heat emitting surface of the first thermoelectric element; and

and the hot-side radiator is connected with the heating surface of the second thermoelectric element in a heat conduction manner.

16. The thermoelectric module of claim 15,

further comprising an intermediate substrate sandwiched between the first thermoelectric element and the second thermoelectric element,

the first thermoelectric element includes:

a heat absorption side substrate coupled to the cold side heat sink;

a first semiconductor element section having one end portion thereof electrode-bonded to the heat absorption-side substrate and the other end portion thereof electrode-bonded to the intermediate substrate; and

a first sealing member for sealing the semiconductor element portion by connecting edges of the heat absorption side substrate and the intermediate substrate,

the second thermoelectric element includes:

a heat-generating side substrate coupled to the hot-side heat sink;

a second semiconductor element section having one end portion thereof bonded to the intermediate substrate via an electrode portion and the other end portion thereof bonded to the heat-generating-side substrate via an electrode portion; and

and a second sealing member that seals the semiconductor element section by connecting edges of the heat-generating side substrate and the intermediate substrate.

17. The thermoelectric module of claim 15,

the first thermoelectric element and the second thermoelectric element each include:

a heat absorption side substrate;

a heat-generating side substrate;

a semiconductor element section having both ends thereof respectively soldered to the heat absorption-side substrate and the heat generation-side substrate via electrode sections; and

a sealing member for sealing the semiconductor element section by connecting edges of the heat absorption-side substrate and the heat generation-side substrate,

the heat-generating-side substrate of the first thermoelectric element and the heat-absorbing-side substrate of the second thermoelectric element are attached to each other in a thermally conductive manner.

18. A refrigerator, characterized by comprising:

a case provided with a storage chamber maintained at a set temperature lower than an indoor temperature;

a door for opening and closing the storage chamber; and

the thermoelectric module of any one of claims 1 to 17 for cooling the temperature of the storage chamber to the set temperature,

a cold-side heat sink constituting the thermoelectric module is exposed to the storage chamber,

a hot-side heat sink constituting the thermoelectric module is disposed outside the storage chamber.

19. The refrigerator of claim 18,

the storage chamber includes any one of a refrigerating chamber, a freezing chamber and a deep freezing chamber,

the refrigerating compartment is maintained at a temperature above freezing temperature, the freezing compartment is maintained at a temperature below freezing temperature, and the deep-freezing compartment is maintained at a temperature below freezing temperature.

20. The refrigerator of claim 19,

the deep freezing chamber is arranged inside the freezing chamber,

the cold side heat sink of the thermoelectric module is exposed to the deep freezing chamber.

21. The refrigerator of claim 20, further comprising:

a refrigerating chamber evaporator provided to cool the refrigerating chamber; and

a freezing chamber evaporator connected in parallel with the refrigerating chamber evaporator and provided to cool the freezing chamber,

the hot-side radiator is an evaporator, inside which refrigerant flows,

the hot side radiator is connected in series with the inlet or the outlet of the freezing chamber evaporator.

22. A thermoelectric module, comprising: a cold-side heat sink (22); a first thermoelectric element (40a) having a heat absorbing surface connected to the cold-side heat sink; a second thermoelectric element (40b) having a heat absorbing surface connected to the heat emitting surface of the first thermoelectric element; and a hot-side heat sink (24) connected to the heat emitting surface of the second thermoelectric element and releasing heat transferred from the cold-side heat sink to the outside,

the first thermoelectric element includes:

a semiconductor element section including a P-type semiconductor and an N-type semiconductor;

a heat absorption side electrode portion formed at one end of the semiconductor element portion and connected to the cold side heat sink; and

a heat-generating-side electrode portion formed at the other end of the semiconductor element portion and connected to the heat-absorbing surface of the second thermoelectric element,

the second thermoelectric element includes:

a semiconductor element section including a P-type semiconductor and an N-type semiconductor;

a heat absorption side electrode portion formed at one end of the semiconductor element portion and connected to the heat generation surface of the first thermoelectric element; and

a heat-generating-side electrode portion formed at the other end of the semiconductor element portion and connected to the heat-side heat sink,

the thermoelectric module further includes:

a sealing cover connecting and sealing an edge of the cold-side heat sink and an edge of the hot-side heat sink in a state of being spaced apart from the first thermoelectric element and the second thermoelectric element, to improve heat transfer efficiency of the thermoelectric module;

a first heat sink connected between the cold-side heat sink and a heat-absorbing-side electrode portion of the first thermoelectric element; and

and a second heat sink connected between the hot-side heat sink and the heat-generating-side electrode portion of the second thermoelectric element.

23. The thermoelectric module of claim 22,

the thermoelectric module further comprises a heat transfer block which is clamped between the joint parts of the first thermoelectric element and the second thermoelectric element so as to reduce the phenomenon that heat transferred from the cold side radiator flows back without flowing to the hot side radiator,

the heat absorption side electrode portion of the first thermoelectric element is attached to the cold-side heat sink,

the heat-generating-side electrode portion of the second thermoelectric element is attached to the hot-side heat sink,

the heat-generating-side electrode portion of the first thermoelectric element is attached to one surface of the heat transfer block,

the heat absorption-side electrode portion of the second thermoelectric element is attached to the other surface of the heat transfer block.

24. The thermoelectric module of claim 22,

applying any one of a high voltage and a low voltage lower than the high voltage to the first thermoelectric element and the second thermoelectric element,

the voltage applied to the second thermoelectric element is greater than the voltage applied to the first thermoelectric element.

25. The thermoelectric module of claim 22,

a temperature difference (DeltaT 1) between a heat absorbing surface and a heat generating surface of the first thermoelectric element is set to be greater than or equal to a temperature difference (DeltaT 2) between a heat absorbing surface and a heat generating surface of the second thermoelectric element.

Technical Field

The invention relates to a thermoelectric module and a refrigerator comprising the same.

Background

In general, a refrigerator, which is a home appliance for storing food at a low temperature, includes a refrigerating chamber for storing food in a refrigerated state in a range of 3 ℃ and a freezing chamber for storing food in a frozen state in a range of-20 ℃.

However, if food such as meat or seafood is stored in a frozen state in the current freezing chamber, water in cells of the meat or seafood flows out of the cells to cause the cells to be damaged during freezing of the food to-20 ℃, and a phenomenon in which the taste is changed during thawing occurs.

However, if the temperature condition of the storage chamber is set to a very low temperature state significantly lower than the current freezing chamber temperature, whereby the food rapidly passes through the freezing point temperature range when changing to the frozen state, it is possible to minimize cell destruction, and as a result, there is an advantage that the meat quality and taste after thawing can be restored to a state close to the state before freezing. The very low temperature is understood to mean a temperature in the range from-45 ℃ to-50 ℃.

For this reason, in recent years, the demand for a refrigerator provided with a deep freezing chamber that maintains a temperature lower than that of the freezing chamber is gradually increasing.

In order to meet the demand for the deep freezing chamber, there is a limit in cooling using an existing refrigerant, and thus, an attempt is being made to lower the temperature of the deep freezing chamber to an extremely low temperature using a ThermoElectric Element (TEM).

Korean laid-open patent No. 2018-0105572 (09/28/2018) as a prior art discloses a refrigerator in the form of a bedside cabinet in which a storage chamber is stored at a temperature lower than the indoor temperature using a thermoelectric module.

However, in the case of the refrigerator using the thermoelectric module disclosed in the above-mentioned prior art, since the heat generating surface of the thermoelectric module has a structure in which it is cooled by heat exchange with the indoor air, there is a limit to reduce the temperature of the heat absorbing surface.

In detail, with the thermoelectric module, if the supply current increases, the temperature difference between the heat absorbing surface and the heat generating surface tends to increase to a certain level. However, in consideration of the characteristics of the thermoelectric element made of a semiconductor element, if the supply current increases, the semiconductor functions as a resistance, resulting in an increase in self-heating value. Then, there is a problem that the heat absorbed from the heat absorbing surface cannot be quickly transferred to the heat generating surface.

Furthermore, if the heat generating surface of the thermoelectric element is not sufficiently cooled, the heat transferred to the heat generating surface flows back to the heat absorbing surface side, and the temperature of the heat absorbing surface is also increased.

In the case of the thermoelectric module disclosed in the related art, since the heat generating surface is cooled by the indoor air, there is a limit that the temperature of the heat generating surface cannot be made lower than the indoor temperature.

In a state where the temperature of the heat generating surface is substantially fixed, it is necessary to increase the supply current to lower the temperature of the heat absorbing surface, thereby causing a problem of lowering the efficiency of the thermoelectric module.

In addition, if the supply current is increased, the temperature difference between the heat absorbing surface and the heat generating surface becomes large, resulting in a decrease in the cooling capability of the thermoelectric module.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made to solve the above problems.

Technical scheme for solving problems

In order to achieve the above object, a thermoelectric module according to an embodiment of the present invention may include: a cold side heat sink; a thermoelectric element having a heat absorbing surface coupled to the cold-side heat sink; a hot-side heat sink coupled to a heat emitting surface of the thermoelectric element and releasing heat transferred from the cold-side heat sink to the outside of the thermoelectric element; and a sealing cover connecting an edge of the cold-side heat sink and an edge of the hot-side heat sink and surrounding the thermoelectric element, the cold-side heat sink, the hot-side heat sink, and the thermoelectric element being integrally formed by the sealing cover.

The thermoelectric element may be a cascade thermoelectric element in which two thermoelectric elements having the same or different specifications are combined.

In addition, in the above-described tandem thermoelectric element, the ceramic substrate in the related art is replaced with a heat sink, and a metal block is interposed at the joint portion of the two thermoelectric elements, so that the thickness of the thermoelectric module can be significantly reduced.

In addition, a thermoelectric module in which a hot-side radiator and a cold-side radiator are integrated or a cascade type thermoelectric module may be disposed in a deep freezing chamber of a refrigerator, thereby using the thermoelectric module in a process of cooling the deep freezing chamber to an ultra-low temperature of about-50 ℃.

Effects of the invention

According to the thermoelectric module having the above-described configuration and the refrigerator including the same, the following effects are provided.

First, since the ceramic substrates provided at both end portions of the thermoelectric element are removed, there is an advantage in that the thickness of the thermoelectric module is reduced.

Second, the solder wetting is improved by changing the plating material for the electrode portion of the semiconductor element constituting the thermoelectric element from tin (Sn) to gold (Au), thereby improving the soldering stability of the semiconductor element.

Third, since the ceramic substrate is removed, there is an advantage in that a coating process of thermal grease (thermal grease) for bonding the ceramic substrate with the hot-side heat sink or the cold-side heat sink is eliminated.

Fourth, instead of a relatively thick ceramic substrate, heat sinks are interposed at both ends of the semiconductor element, and the heat sinks are integrated with a hot-side heat sink, a heat sink and a cold-side heat sink, thereby having an advantage of significantly increasing a heat transfer effect.

Fifth, a process for sealing (sealing) the side of the thermoelectric element is eliminated, and a sealing cover for directly connecting the hot-side and cold-side heat spreaders is provided, thereby having effects of simplifying the manufacturing process and reducing the manufacturing cost.

Drawings

Fig. 1 is a diagram illustrating a refrigerant cycle system of a refrigerator according to an embodiment of the present invention.

Fig. 2 is a perspective view illustrating the structures of a freezing chamber and a deep freezing chamber of a refrigerator according to an embodiment of the present invention.

Fig. 3 is a longitudinal sectional view taken along line 3-3 of fig. 2.

Fig. 4 is a graph showing cooling capacity versus input voltage and fourier effect.

Fig. 5 is a graph showing the efficiency relationship with respect to the input voltage and the fourier effect.

Fig. 6 is a graph showing the correlation of the cooling capacity and the efficiency based on the voltage.

Fig. 7 is a graph illustrating a reference temperature line for controlling the refrigerator according to a load variation inside the refrigerator.

Fig. 8 is a sectional view of a thermoelectric module according to a first embodiment of the present invention.

Fig. 9 is a sectional view of a thermoelectric module according to a second embodiment of the present invention.

Fig. 10 is a sectional view of a thermoelectric module according to a third embodiment of the present invention.

Fig. 11 is a sectional view of a thermoelectric module according to a fourth embodiment of the present invention.

Fig. 12 is a sectional view of a thermoelectric module according to a fifth embodiment of the present invention.

Fig. 13 is a sectional view of a thermoelectric module of a sixth embodiment of the present invention.

Detailed Description

Hereinafter, a thermoelectric module and a refrigerator including the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present invention, a storage chamber that is cooled by a first cooling device and can be controlled to a prescribed temperature may be defined as the first storage chamber.

In addition, a storage chamber that is cooled by the second cooler and can be controlled to a temperature lower than that of the first storage chamber may be defined as the second storage chamber.

In addition, a storage chamber that is cooled by a third cooler and can be controlled to a temperature lower than that of the second storage chamber may be defined as a third storage chamber.

The first cooler for cooling the first storage chamber may include at least one of a first evaporator and a first thermoelectric module including a thermoelectric element. The first evaporator may include a refrigerating compartment evaporator described later.

The second cooler for cooling the second storage chamber may include at least one of a second evaporator and a second thermoelectric module including a thermoelectric element. The second evaporator may include a freezing chamber evaporator described later.

The third cooler for cooling the third storage chamber may include at least one of a third evaporator and a third thermoelectric module including a thermoelectric element.

In the present specification, for an embodiment in which a thermoelectric module is used as a cooling device, an evaporator can be applied instead of the thermoelectric module, and the following example is given.

(1) The "cold-side heat sink of the thermoelectric module" or the "heat absorbing surface of the thermoelectric element" or the "heat absorbing side of the thermoelectric module" may be interpreted as "evaporator or one side of the evaporator".

(2) The "heat absorption side of the thermoelectric module" may be interpreted as the same meaning as "cold-side heat sink of the thermoelectric module" or "heat absorption surface of the thermoelectric module".

(3) The control portion "apply or cut off the forward voltage to the thermoelectric module" may be understood as any one of "supply or cut off the refrigerant to the evaporator", "control to switch the valve to be opened or closed", or "control to switch the compressor to be opened or closed".

(4) The control portion "controls to increase or decrease the forward voltage applied to the thermoelectric module" may be understood as any one of "controlling the flow rate or flow rate of the refrigerant flowing to the evaporator to increase or decrease", "controlling the opening degree of the switching valve to increase or decrease", or "controlling the output of the compressor to increase or decrease".

(5) The control portion "controls the reverse voltage applied to the thermoelectric module to increase or decrease" may be understood as "controlling the voltage applied to the defrosting heater adjacent to the evaporator to increase or decrease".

On the other hand, in the present specification, "a storage chamber cooled by a thermoelectric module" may be defined as a storage chamber a, and "a fan located at a position adjacent to the thermoelectric module and configured to exchange heat between air inside the storage chamber a and a heat absorbing surface of the thermoelectric module" may be defined as a storage chamber a fan.

In addition, a storage chamber which constitutes a refrigerator together with the storage chamber a and is cooled by a cooler may be defined as "storage chamber B".

In addition, the "cooler compartment" may be defined as a space where the cooler is located, and in a structure in which a fan for blowing cool air generated from the cooler is further provided, may be defined as including a space for accommodating the fan, and in a structure in which a flow path for guiding cool air blown from the fan to the storage chamber or a flow path for discharging defrost water is further provided, may be defined as including the flow path.

In the present invention, the first storage chamber may include a refrigerating chamber, and the refrigerating chamber may be controlled to a temperature above zero by the first cooler, as an example.

In addition, the second storage chamber may include a freezing chamber, and the freezing chamber may be controlled to a sub-zero temperature by the second cooler.

In addition, the third storage chamber may include a deep freezing chamber (deep freezing chamber) which may be maintained at a very low temperature (cryogenic temperature) or an ultra-low temperature (ultra-freezing temperature) by the third cooler.

In addition, the invention does not exclude: a case where the first to third storage chambers are all controlled to a subzero temperature; a case where the first to third storage chambers are all controlled to a temperature above zero; and a case where the first storage chamber and the second storage chamber are controlled to an above-zero temperature, and the third storage chamber is controlled to a below-zero temperature.

Hereinafter, as an example, a case where the first storage chamber is a refrigerating chamber, the second storage chamber is a freezing chamber, and the third storage chamber is a deep freezing chamber will be described.

Fig. 1 is a diagram illustrating a refrigerant cycle system of a refrigerator according to an embodiment of the present invention.

Referring to fig. 1, a refrigerant cycle system 10 of an embodiment of the present invention includes: a compressor 11 for compressing a refrigerant into a high-temperature high-pressure gas refrigerant; a condenser 12 for condensing the refrigerant discharged from the compressor 11 into a high-temperature and high-pressure liquid refrigerant; an expansion valve for expanding the refrigerant discharged from the condenser 12 into a low-temperature low-pressure two-phase refrigerant; and an evaporator for evaporating the refrigerant flowing through the expansion valve into a low-temperature low-pressure gas refrigerant. The refrigerant discharged from the evaporator flows into the compressor 11. The above-described configuration is connected to each other by refrigerant pipes to form a closed circuit.

In detail, the expansion valves may include a refrigerating compartment expansion valve 14 and a freezing compartment expansion valve 15. The refrigerant pipe is divided into two branches at the outlet side of the condenser 12, and the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15 are connected to the refrigerant pipe divided into two branches, respectively. That is, the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15 are connected in parallel at the outlet side of the condenser 12.

A switching valve 13 is attached to the outlet side of the condenser 12 at a position where the refrigerant pipe is divided into two branches. By the adjustment operation of the opening degree of the switching valve 13, the refrigerant flowing through the condenser 12 can be made to flow only to one of the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15, or can be branched to both sides.

The switching valve 13 may be a three-way valve, and determines a flow direction of the refrigerant according to an operation mode. Here, one switching valve, for example, the three-way valve may be attached to the outlet side of the condenser 12 to control the flow direction of the refrigerant, or alternatively, an opening/closing valve may be attached to each of the inlets of the refrigerating chamber expansion valve 14 and the freezing chamber expansion valve 15.

On the other hand, as a first example of the configuration of the evaporator, the evaporator may include: a refrigerating chamber evaporator 16 connected to an outlet side of the refrigerating chamber expansion valve 14; and a hot-side radiator 24 and a freezing chamber evaporator 17 connected in series to an outlet side of the freezing chamber expansion valve 15. The hot side radiator 24 and the freezing chamber evaporator 17 are connected in series, and the refrigerant flowing through the freezing chamber expansion valve flows into the freezing chamber evaporator 17 after passing through the hot side radiator 24.

As a second example, it is clear that the following structure may also be adopted: the hot-side radiator 24 is disposed on the outlet side of the freezing chamber evaporator 17, and thus the refrigerant flowing through the freezing chamber evaporator 17 flows into the hot-side radiator 24.

As a third example, a structure in which the deep freezing chamber evaporator 24 and the freezing chamber evaporator 17 are connected in parallel at the outlet end of the freezing chamber expansion valve 15 is not excluded.

The hot-side radiator 24 is an evaporator, but is provided for the purpose of cooling a heat generating surface of a thermoelectric module described later, not for heat exchange with cold air in a deep freezing chamber.

In each of the three examples described above for the method of arranging the evaporators, a combined system may be adopted in which the switching valve 13, the refrigerating room expansion valve 14, and the refrigerating room evaporator 16 are eliminated, and a first refrigerant circulation system including a refrigerating room cooling evaporator, a refrigerating room cooling expansion valve, a refrigerating room cooling condenser, and a refrigerating room cooling compressor is combined.

Here, the condenser for constituting the first refrigerant circulation system and the condenser for constituting the second refrigerant circulation system may be separately provided, or a combined condenser, which is a condenser composed of a single body and does not mix refrigerants, may be provided.

On the other hand, in the refrigerant cycle system of the refrigerator including the deep freezing chamber to form two storage chambers, only the first refrigerant cycle system may be provided.

Hereinafter, as an example, a description will be given of a configuration in which the hot-side radiator and the freezing compartment evaporator 17 are connected in series.

A condensing fan 121 is installed at a position adjacent to the condenser 12, a refrigerating compartment fan 161 is installed at a position adjacent to the refrigerating compartment evaporator 16, and a freezing compartment fan 171 is installed at a position adjacent to the freezing compartment evaporator 17.

On the other hand, inside the refrigerator having the refrigerant cycle system according to the embodiment of the present invention, there are formed: a refrigerating compartment maintained at a refrigerating temperature by cold air generated by the refrigerating compartment evaporator 16; a freezing chamber maintained at a freezing temperature using cold air generated by the freezing chamber evaporator 16; and a deep freezing chamber (deep freezing chamber) 202 that maintains a temperature of an ultra low temperature (cryogenic) or an ultra low temperature (ultra freezing) using a thermoelectric module to be described later. The refrigerating chamber and the freezing chamber may be adjacently disposed in an up-down direction or a left-right direction, and separated from each other by a partition wall. The deep freezing chamber may be provided at one side of the inside of the freezing chamber, but the present invention includes a case where the deep freezing chamber is provided at one side of the outside of the freezing chamber. In order to block the cold air of the deep freezing chamber and the cold air of the freezing chamber from exchanging heat with each other, the deep freezing chamber 202 may be partitioned from the freezing chamber by a deep freezing case 201 having high heat insulation performance.

In addition, the thermoelectric module may include: a thermoelectric element 40 which, when power is supplied to the thermoelectric element 40, exhibits a characteristic in which one side absorbs heat and the opposite side releases heat; a cold-side heat sink (cold sink)22 mounted to a heat absorbing surface of the thermoelectric element 40; a hot-side heat sink (heat sink)24 mounted to a heat generating face of the thermoelectric element 40; and an insulating material 23 for blocking heat exchange between the cold side radiator 22 and the hot side radiator 24.

According to the example of the thermoelectric element 40 described below, the heat insulating material 23 may not be required.

Here, the hot-side heat sink 24 is an evaporator that is in contact with the heat generating surface of the thermoelectric element 40. That is, the heat transferred to the heat generating surfaces of the thermoelectric elements 40 exchanges heat with the refrigerant flowing through the inside of the hot-side radiator 24. The refrigerant flowing along the inside of the hot-side radiator 24 and absorbing heat from the heat generating surfaces of the thermoelectric elements 40 flows into the freezing compartment evaporator 17.

In addition, a cooling fan may be provided in front of the cold-side radiator 22, and the cooling fan may be disposed at a rear side of the interior of the deep freezing chamber, and thus may be defined as a deep freezing chamber fan 25.

The cold-side radiator 22 is disposed behind the interior of the deep freezing chamber 202 and is configured to be exposed to cold air in the deep freezing chamber 202. Therefore, if the cold air of the deep freezing chamber 202 is forcibly circulated by driving the deep freezing chamber fan 25, the cold-side radiator 22 functions to transfer the absorbed heat to the heat absorbing surface of the thermoelectric element 40 after absorbing the heat through heat exchange with the cold air of the deep freezing chamber. The heat transferred to the heat absorbing surface is transferred to the heat generating surface of the thermoelectric element 40.

The hot-side heat sink 24 functions to absorb heat again, which is absorbed from the heat absorbing surface of the thermoelectric element 40 and transferred to the heat generating surface of the thermoelectric element 40, and then to be discharged to the outside of the thermoelectric module 20.

Fig. 2 is a perspective view showing the structures of a freezing chamber and a deep freezing chamber of a refrigerator according to an embodiment of the present invention, and fig. 3 is a longitudinal sectional view taken along line 3-3 of fig. 2.

Referring to fig. 2 and 3, a refrigerator according to an embodiment of the present invention includes: an inner case 101 defining a freezing chamber 102; and a deep freezing unit 200 installed at one side of the inside of the freezing chamber 102.

In detail, the inside of the refrigerating chamber is maintained at about 3 ℃, the inside of the freezing chamber 102 is maintained at about-18 ℃, and the temperature of the inside of the deep freezing unit 200, i.e., the inside temperature of the deep freezing chamber 202, needs to be maintained at about-50 ℃. Therefore, in order to maintain the internal temperature of the deep freezing chamber 202 at a very low temperature of-50 ℃, an additional freezing device such as the thermoelectric module 20 is required in addition to the freezing chamber evaporator.

In more detail, the deep freezing unit 200 includes: a deep freezing casing 201 in which a deep freezing chamber 202 is formed; a deep freezing chamber drawer 203 slidably inserted into the interior of the deep freezing casing 201; and a thermoelectric module 20 mounted on a rear surface of the deep freezing case 201.

Instead of using the deep freezing chamber drawer 203, a deep freezing chamber door may be connected to a front side of the deep freezing case 201, and the entire inside of the deep freezing case 201 may be configured as a food storage space.

In addition, the rear surface of the inner case 101 is stepped toward the rear, thereby forming a freezing-evaporating chamber 104 for receiving the freezing chamber evaporator 17. In addition, the inner space of the inner case 101 is partitioned into the freezing and evaporating chamber 104 and the freezing chamber 102 by a partition wall 103. The thermoelectric module 20 is fixedly attached to the front surface of the partition wall 103, and a part of the thermoelectric module 20 penetrates the deep freezing casing 201 and is accommodated in the deep freezing chamber 202.

In detail, as described above, the hot-side radiator 24 for constituting the thermoelectric module 20 may be an evaporator connected to the freezing chamber expansion valve 15. A space for accommodating the hot-side heat sink 24 may be formed in the partition wall 103.

The two-phase refrigerant, which is cooled to about-18 to-20 c while flowing through the freezing chamber expansion valve 15, flows inside the hot side radiator 24, so that the surface temperature of the hot side radiator 24 is maintained at-18 to-20 c. Here, it should be clear that the temperature and pressure of the refrigerant flowing through the freezing compartment expansion valve 15 may be different according to the freezing compartment temperature condition.

When the front surface of the hot-side heat sink 24 is in contact with the rear surface of the thermoelectric element 40 and power is applied to the thermoelectric element 40, the rear surface of the thermoelectric element 40 is formed as a heat-generating surface.

When the cold-side heat sink 22 is brought into contact with the front surface of the thermoelectric element 40 and power is applied to the thermoelectric element 40, the front surface of the thermoelectric element 40 is formed as a heat absorbing surface.

The cold side heat sink 22 may include: a heat-conducting plate made of an aluminum material; and a plurality of heat exchange fins (fin) extending from the front surface of the heat conductive plate, which may extend vertically and be disposed to be spaced apart in a lateral direction.

Here, in the case where a case for surrounding or accommodating at least a part of a heat conductor composed of a heat conductive plate and heat exchange fins is provided, the cold-side heat sink 22 should be interpreted as including not only the heat conductor but also a heat transfer member of the case. The same applies to the hot-side heat sink 24, which hot-side heat sink 24 is to be understood not only as a heat conductor consisting of a heat conducting plate and heat exchange fins, but also, in the case of a housing, as a heat transfer component comprising a housing.

The deep freezing chamber fan 25 is disposed in front of the cold-side radiator 22, and the air inside the deep freezing chamber 202 is forcibly circulated.

The efficiency and cooling capacity of the thermoelectric element will be described below.

The efficiency of the thermoelectric module 20 may be defined as a Coefficient of performance (COP), and the efficiency equation is as follows.

Q_c: cooling Capacity (Capacity to absorb Heat)

P_e: input (Input Power, Power supplied to the thermoelectric element)

P_e＝V×i

In addition, the cooling capacity of the thermoelectric module 20 is defined as follows.

< coefficient of characteristics of semiconductor Material >

α: seebeck (Seebeck) coefficient [ V/K ]

ρ: resistivity [ omega m-1]

k: thermal conductivity [ W/mk ]

< semiconductor Structure characteristics >

L: thickness of thermoelectric element: distance between heat absorbing surface and heat generating surface

A: area of thermoelectric element

< conditions for System use >

i: electric current

V: voltage of

T_h: temperature of heat generating surface of thermoelectric element

T_c: temperature of heat absorbing surface of thermoelectric element

In the above cooling capacity equation, the first term on the right side may be defined as the peltier effect, and may be defined as the amount of moving heat between both ends of the heat absorbing surface and the heat generating surface caused by the voltage difference. The peltier effect increases as a function of current, in proportion to the supply current.

In the formula V ═ iR, the semiconductor used to constitute the thermoelectric element functions as a resistance, and the resistance can be regarded as a constant, so it can be said that the voltage and the current are in a proportional relationship. That is, when the voltage applied to the thermoelectric element 40 is increased, the current is also increased. The peltier effect can therefore be seen as a function of current, but also as a function of voltage.

The cooling capacity can also be regarded as a function of the current or as a function of the voltage. The peltier effect acts as a positive effect for increasing the cooling capacity. That is, if the supply voltage becomes large, the peltier effect increases, and the cooling capacity increases.

In the cooling capacity formula, the second term on the right side is defined as Joule Effect (Joule Effect).

The joule effect is an effect that generates heat when a current is applied to the resistor. In other words, heat is generated if power is supplied to the thermoelectric element, and thus it has a negative effect of reducing cooling capacity. Therefore, if the voltage supplied to the thermoelectric element is increased, the joule effect is increased, and the cooling capability of the thermoelectric element is reduced.

In the cooling capacity equation, the third term on the right side is defined as Fourier Effect.

The fourier effect is an effect in which heat moves by heat conduction when a temperature difference occurs between both surfaces of the thermoelectric element.

In detail, the thermoelectric element includes: a heat absorbing surface and a heat emitting surface formed of a ceramic substrate; and a semiconductor element disposed between the heat absorbing surface and the heat generating surface. When a voltage is applied to the thermoelectric element, a temperature difference occurs between the heat absorbing surface and the heat generating surface. The heat absorbed by the heat absorbing surface passes through the semiconductor and is transferred to the heat generating surface. However, when a temperature difference occurs between the heat absorbing surface and the heat generating surface, heat flows back from the heat generating surface to the heat absorbing surface by heat conduction, and this phenomenon is referred to as a fourier effect.

Like the joule effect, the fourier effect also acts as a negative effect to reduce the cooling capacity. In other words, if the supply current increases, the temperature difference (T) between the heat-generating surface and the heat-absorbing surface of the thermoelectric element increases_h-T_c) That is, the Δ T value increases, resulting in a decrease in cooling capacity.

Fig. 4 is a graph showing cooling capacity versus input voltage and fourier effect.

Referring to fig. 4, the fourier effect may be defined as a function of the temperature difference between the heat absorbing surface and the heat emitting surface, i.e., Δ T.

Specifically, when the specification of the thermoelectric element is determined, the k value, the a value, and the L value in the fourier effect term of the cooling capacity equation are constant values, and therefore the fourier effect can be regarded as a function having Δ T as a variable.

Therefore, as Δ T increases, the fourier effect value increases, but the fourier effect has a negative effect on the cooling capacity, and as a result, the cooling capacity will decrease.

As shown in the graph of fig. 4, it is understood that the larger Δ T is, the smaller the cooling capacity is under the condition that the voltage is constant.

In addition, in a state where Δ T has been set, for example, if it is defined that Δ T is 30 ℃ and a change in cooling capacity based on a change in voltage is observed, a parabolic form will be exhibited, that is, as the voltage value increases, the cooling capacity increases, and thereafter, a maximum value appears at a certain point, and then, it again decreases.

Here, it should be clear that since the voltage and the current are proportional, the current described in the cooling capacity equation may be interpreted as the voltage and the same manner.

In detail, as the supply voltage (or current) increases, the cooling capacity increases, which can be explained in the above cooling capacity formula. First, since the Δ T value has been set, it is formed as a constant. Since the Δ T value of the thermoelectric element per specification is determined, an appropriate specification of the thermoelectric element can be set according to the required Δ T value.

Since Δ T has been set, the fourier effect can be regarded as a constant, and as a result, the cooling capacity can be simplified as a function of the peltier effect, which can be regarded as a primary function of voltage (or current), and the joule effect, which can be regarded as a secondary function of voltage (or current).

As the voltage value gradually increases, the increase in the peltier effect as a primary function of the voltage is larger than the increase in the joule effect as a secondary function of the voltage, and as a result, the cooling capacity assumes an increased state. In other words, until the cooling capacity reaches a maximum, the function of the joule effect approaches a constant, whereby the cooling capacity takes a form close to a linear function of the voltage.

As the voltage further increases, a reverse phenomenon occurs in which the self-heating value due to the joule effect is larger than the moving heat value due to the peltier effect, and as a result, it is confirmed that the cooling capacity is again reduced. This can be understood more clearly by the relation between the peltier effect as a primary function of voltage (or current) and the joule effect as a function of the second order function of voltage (or current). That is, when the cooling capacity is reduced, the cooling capacity takes a form close to a quadratic function of voltage.

In the graph of fig. 4, it can be confirmed that the cooling capacity is maximized when the supply voltage is in the interval ranging from about 30V to 40V, more particularly, about 35V. Therefore, if only the cooling capacity is taken into consideration, it can be said that it is preferable to generate a voltage difference in the range of 30V to 40V in the thermoelectric element.

Fig. 5 is a graph showing the efficiency relationship with respect to the input voltage and the fourier effect.

Referring to fig. 5, it can be confirmed that the greater the Δ T with respect to the same voltage, the lower the efficiency. This is a natural consequence, as efficiency is proportional to cooling capacity.

In addition, in a state where Δ T has been fixed, for example, if it is defined that Δ T is 30 ℃ and a change in efficiency based on a voltage change is observed, the following state will be exhibited: as the supply voltage increases, the efficiency also increases together, and then at a certain point of time, the efficiency decreases instead. It can be said that this is similar to a graph of cooling capacity based on voltage variation.

Here, the efficiency (COP) is not only a function of the cooling capacity but also a function of the input power, and if the resistance of the thermoelectric element 40 is regarded as a constant, the input (Pe) is formed as V²As a function of (c). If the cooling capacity is divided by V²Efficiency can finally be expressed asThus, it can be seen that the graph of the efficiency takes the form shown in fig. 5.

In the graph of fig. 5, it can be confirmed that: the point where the efficiency is the greatest occurs in the region where the voltage difference (or supply voltage) applied to the thermoelectric element is substantially less than 20V. Therefore, if the required Δ T has been determined, it is preferable to apply an appropriate voltage in accordance with the Δ T, thereby maximizing the efficiency. That is, if the temperature of the hot-side heat sink and the set temperature of the deep freezing chamber 202 are determined, Δ T will be determined, and the optimum voltage difference applied to the thermoelectric element can be determined from the Δ T.

Fig. 6 is a graph showing a voltage-based cooling capacity versus efficiency.

Referring to fig. 6, as described above, a state is shown in which the cooling capacity and the efficiency both increase and then decrease as the voltage difference increases.

In detail, it can be seen that the voltage value at which the cooling capacity is maximized and the voltage value at which the efficiency is maximized are different, which can be seen because the cooling capacity is a linear function of the voltage until the maximum is reached and the efficiency is a quadratic function of the voltage.

As shown in fig. 6, for example, it was confirmed that, in the case of the thermoelectric element having a Δ T of 30 ℃, the efficiency of the thermoelectric element was the highest in the range of about 12V to 17V of the voltage difference applied to the thermoelectric element. In the range of the voltage, the cooling capacity exhibits a state of continuing to increase. Therefore, it is understood that a voltage difference of at least 12V or more is required in consideration of the cooling capacity, and the efficiency is the highest when the voltage difference is 14V.

Fig. 7 is a graph illustrating a reference temperature line for controlling the refrigerator according to a load variation inside the refrigerator.

Hereinafter, the set temperature of each storage chamber is defined as a notch temperature (notch temperature) and will be described. The reference temperature line may also be denoted as a critical temperature line.

In the graph, the reference temperature line on the lower side is a reference temperature line for distinguishing the satisfied temperature region from the unsatisfied temperature region. Therefore, the lower region a of the lower reference temperature line may be defined as a satisfied section or a satisfied region, and the upper region B of the lower reference temperature line may be defined as a non-satisfied section or a non-satisfied region.

In addition, the reference temperature line on the upper side is a reference temperature line for distinguishing the region not satisfying the temperature and the upper limit temperature region. Therefore, the upper region C of the upper reference temperature line may be defined as an upper limit region or an upper limit section, and may be regarded as a special operating region.

On the other hand, when defining the satisfied/unsatisfied/upper limit temperature area for controlling the refrigerator, the lower reference temperature line may be defined as any one of a case of being included in the satisfied temperature area and a case of being included in the unsatisfied temperature area. In addition, the upper reference temperature line may be defined as one of a case included in the non-temperature-satisfying region and a case included in the upper limit temperature region.

When the temperature inside the refrigerator is in the satisfaction region a, the compressor is not driven, and when the temperature inside the refrigerator is in the non-satisfaction region B, the temperature inside the refrigerator is brought into the satisfaction region by driving the compressor.

In addition, the case where the temperature of the inside of the refrigerator is in the upper limit region C may be regarded as a case where the load of the inside of the refrigerator is sharply increased due to the food having a high temperature being put into the inside of the refrigerator or the door of the corresponding storage chamber being opened, whereby a special operation algorithm including a load coping operation may be performed.

Fig. 7 (a) is a diagram illustrating a reference temperature line for controlling the refrigerator according to a variation in the temperature of the refrigerating compartment.

The grade temperature N1 of the refrigerating compartment is set to a temperature above zero. Further, in order to maintain the temperature of the refrigerating compartment at the class temperature N1, the compressor driving is controlled when the temperature rises to the first satisfied critical temperature N11 higher than the class temperature N1 by the first temperature difference d1, and the compressor is stopped when the temperature falls to the second satisfied critical temperature N12 lower than the class temperature N1 by the first temperature difference d1 after the compressor is driven.

The first temperature difference d1 is a temperature value increased or decreased from the grade temperature N1 of the refrigerating compartment, and the first temperature difference d1 may be defined as a control difference (control differential) or a control temperature difference (control differential temperature) for defining a temperature interval regarded as the refrigerating compartment temperature being maintained at the grade temperature N1 as a set temperature, and the first temperature difference d1 may be approximately 1.5 ℃.

If it is determined that the temperature of the refrigerating compartment has increased from the class temperature N1 to the first unsatisfied critical temperature N13 higher than the second temperature difference d2, the control is performed so as to execute the special operation algorithm. The second temperature difference d2 may be 4.5 ℃. The first unsatisfied critical temperature may also be defined as an upper input temperature.

If the temperature of the inside of the refrigerator drops to a second unsatisfied temperature N14 lower than the first unsatisfied critical temperature by a third temperature difference d3 after the execution of the special operation algorithm, the operation of the special operation algorithm is ended. The second unsatisfied temperature N14 is lower than the first unsatisfied temperature N13, and the third temperature difference d3 may be 3.0 ℃. The second unsatisfied critical temperature N14 may be defined as an upper limit release temperature.

After the special operation algorithm is finished, the temperature inside the refrigerator reaches the second satisfied critical temperature N12 by adjusting the cooling capacity of the compressor, and then the driving of the compressor is stopped.

Fig. 7 (b) is a graph showing a reference temperature line for controlling the refrigerator according to a variation in the temperature of the freezing chamber.

The form of the reference temperature line for controlling the temperature of the freezing compartment is the same as that of the reference temperature line for controlling the temperature of the refrigerating compartment except that the grade temperature N2 and the temperature variation amounts k1, k2, and k3, which are increased or decreased from the grade temperature N2, are different from the grade temperature N1 and the temperature variation amounts d1, d2, and d3 of the refrigerating compartment.

As described above, the freezing compartment grade temperature N2 may be-18 ℃, but is not limited thereto. The control temperature difference k1 for defining a temperature interval, which is regarded as the temperature of the freezing chamber being maintained at the class temperature N2 as the set temperature, may be 2 ℃.

Therefore, when the freezer temperature rises to the first satisfied threshold temperature N21 higher than the rank temperature N2 by the first temperature difference k1, the compressor is driven, and when the first unsatisfied threshold temperature (upper limit input temperature) N23 higher than the rank temperature N2 by the second temperature difference k2, the special operation algorithm is executed.

After the compressor is driven, if the freezing compartment temperature drops to the second satisfied critical temperature N22, which is lower than the rank temperature N2 by the first temperature difference k1, the driving of the compressor is stopped.

After the execution of the special operation algorithm, if the freezing compartment temperature drops to the second unsatisfied critical temperature (upper limit releasing temperature) N24, which is lower than the first unsatisfied temperature N23 by the third temperature difference k3, the execution of the special operation algorithm is ended. The freezer compartment temperature is reduced to a second, meeting critical temperature N22 by adjusting the compressor cooling capacity.

On the other hand, even in a state where the deep freezing chamber mode has been turned off, it is necessary to intermittently control the temperature of the deep freezing chamber at a predetermined cycle, thereby preventing the temperature of the deep freezing chamber from excessively increasing. Therefore, in a state where the deep freezing chamber mode has been turned off, the temperature control of the deep freezing chamber follows the temperature reference line for controlling the temperature of the freezing chamber shown in (b) of fig. 7.

As described above, the reason why the reference temperature line for controlling the freezing chamber temperature is applied in the state where the deep freezing chamber mode has been turned off is because the deep freezing chamber is located inside the freezing chamber.

That is, even when the deep freezer mode is closed and the deep freezer is not used, the internal temperature of the deep freezer needs to be maintained at least at the same level as the freezer temperature to prevent the load of the freezer from increasing.

Therefore, in a state where the deep freezing chamber mode has been closed, the gradation temperature of the deep freezing chamber is set to be the same as the gradation temperature N2 of the freezing chamber, whereby the first and second satisfied critical temperatures and the first and second unsatisfied critical temperatures are also set to be the same as the critical temperatures N21, N22, N23, N24 for controlling the freezing chamber temperature.

Fig. 7 (c) is a diagram showing a reference temperature line for controlling the refrigerator according to a temperature change of the deep freezing chamber in a state where the deep freezing chamber mode has been turned on.

In a state where the deep freezing chamber mode has been turned on, that is, in a state where the deep freezing chamber is turned on, the grade temperature N3 of the deep freezing chamber is set to a temperature significantly lower than the grade temperature N2 of the freezing chamber, which may be about-45 ℃ to-55 ℃, and may preferably be-55 ℃. In this case, it can be said that the deep freezing chamber graded temperature N3 corresponds to the temperature of the heat absorbing surface of the thermoelectric element 40, and the freezing chamber graded temperature N2 corresponds to the temperature of the heat generating surface of the thermoelectric element 40.

Since the refrigerant passing through the freezing chamber expansion valve 15 passes through the deep freezing chamber evaporator, that is, the hot-side radiator 24, the temperature of the heat generating surface of the thermoelectric element 40 in contact with the hot-side radiator 24 is maintained at least at a temperature corresponding to the temperature of the refrigerant passing through the freezing chamber expansion valve. Therefore, the temperature difference between the heat absorbing surface and the heat generating surface of the thermoelectric element 40, i.e., Δ T, is 32 ℃.

On the other hand, the control temperature difference m1 for defining the temperature interval, i.e., the deep-freezing chamber control temperature difference, may be set higher than the freezing chamber control temperature difference k1, which may be 3 ℃ as an example, the temperature interval is regarded as the deep-freezing chamber being maintained at the level temperature N3 as the set temperature.

Therefore, it can be said that the set temperature holding section defined as the section between the first satisfying critical temperature N31 and the second satisfying critical temperature N32 of the deep freezing chamber is wider than the set temperature of the freezing chamber as the holding section.

Further, the special operation algorithm is executed when the temperature of the deep freezing chamber rises to a first unsatisfied critical temperature N33 higher than the rank temperature N3 by a second temperature difference m2, and the execution of the special operation algorithm is ended when the temperature of the deep freezing chamber drops to a second unsatisfied critical temperature N34 lower than the first unsatisfied critical temperature N33 by a third temperature difference m3 after the execution of the special operation algorithm. The second temperature difference m2 may be 5 ℃.

Here, the second temperature difference m2 of the deep freezing chamber is set to be higher than the second temperature difference k2 of the freezing chamber. In other words, the interval between the first unsatisfied critical temperature N33 for controlling the temperature of the deep freezing chamber and the grade temperature N3 of the deep freezing chamber is set to be greater than the interval between the first unsatisfied critical temperature N23 for controlling the temperature of the freezing chamber and the freezing chamber grade temperature N2.

This is because the internal space of the deep freezing chamber is smaller than the freezing chamber, and the heat insulating performance of the deep freezing case 201 is more excellent, and therefore, the amount of heat load input into the deep freezing chamber released to the outside is small. Furthermore, the temperature of the deep freezing chamber is significantly lower than that of the freezing chamber, and therefore, when a heat load such as food penetrates into the inside of the deep freezing chamber, the sensitivity to the reaction to the heat load is very high.

Thus, in the case where the second temperature difference m2 of the deep freezing chamber is set to be the same as the second temperature difference k2 of the freezing chamber, the execution frequency of a special operation algorithm such as a load-coping operation may become excessively high. Therefore, in order to reduce the frequency of execution of the special operation algorithm and reduce the power consumption, it is preferable to set the second temperature difference m2 of the deep freezing chamber to be greater than the second temperature difference k2 of the freezing chamber.

< first embodiment >

Fig. 8 is a sectional view of a thermoelectric module according to a first embodiment of the present invention.

Referring to fig. 8, the thermoelectric module 20 of the first embodiment of the present invention may include: a thermoelectric element 40; a cold-side heat sink 22 attached to a heat absorbing surface of the thermoelectric element 40; a hot-side heat sink 24 attached to the heat generating surface of the thermoelectric element 40; and a sealing cap 26 connecting edges of the cold side heat sink 22 and the hot side heat sink 24.

As described above, the hot-side heat sink 24 may be an evaporator for passing a low-temperature refrigerant therethrough, but it is clear that, like the cold-side heat sink 22, it may be a metal member having a high thermal conductivity.

In detail, the thermoelectric element 40 may include: a semiconductor element section including a P-type semiconductor element 41 and an N-type semiconductor element 42; a heat absorption side electrode 43 provided at one end of the semiconductor element portion; and a heat-generating-side electrode 44 provided at the other end of the semiconductor element portion.

The heat absorption-side electrode 43 and the heat generation-side electrode 44 may be defined as electrode portions, which may be copper (Cu) electrodes plated with gold (Au). The copper electrode portion is gold-plated with gold, as compared with the electrode portion of the thermoelectric element of the related art made of a copper electrode plated with tin (Sn), whereby an effect of improving solder wetting (solder wetting) can be obtained. The solder wetting refers to a degree that the solder material is uniformly distributed on the substrate, and the improvement of the solder wetting refers to a uniform distribution of the solder material on the substrate in a thin and wide manner.

Therefore, as the solder wetting is improved, the soldering stability of the semiconductor element portion can be improved.

In addition, the thermoelectric element 40 may include: a heat absorption-side heat sink 45 interposed between the heat absorption-side electrode 43 and the cold-side heat sink 22; and a heat generation side fin 46 interposed between the heat generation side electrode 45 and the hot side heat sink 24.

The heat absorption side fins 45 and the heat generation side fins 46 may be defined as fin portions that perform not only a heat transfer function but also an insulation function to prevent current from flowing between the cold side heat sink 22 and the electrode portions or between the hot side heat sink 24 and the electrode portions. That is, it can be understood that the heat-radiating fin portion replaces the function of the ceramic substrate provided in the thermoelectric element in the related art.

In addition, both end portions of the sealing cover 26 are respectively attached to edges of the cold-side heat sink 22 and the hot-side heat sink 24 by an adhesive 261, thereby blocking foreign substances including moisture from flowing into the inside of the thermoelectric element 40.

The thermoelectric element 40, the hot-side heat sink 24, and the cold-side heat sink 22 can be integrally formed by the sealing cover 26, and as a result, the thickness of the thermoelectric module is reduced by the thickness of the heat-absorbing-side ceramic substrate and the heat-generating-side ceramic substrate.

In the case of a typical thermoelectric element, a heat-absorbing side ceramic substrate attached to a heat-absorbing side electrode portion forms a heat-absorbing surface of the thermoelectric element, and a heat-generating side ceramic substrate attached to a heat-generating side electrode portion forms a heat-generating surface of the thermoelectric element.

The ceramic substrate enables heat to be transferred between the heat absorption side and the heat generation side electrode surfaces of the thermoelectric element and the cold side radiator and the heat side radiator, and simultaneously performs an insulation function to prevent current from flowing to the heat absorption side and the heat generation side electrode surfaces and not conducting electricity between the cold side radiator and the heat side radiator.

The thickness of the ceramic substrate may be increased so that the ceramic substrate can withstand damage due to an external force. For example, the thickness of the ceramic substrate may be larger than the thickness of the electrode portion of the thermoelectric element. The thicker the thickness of the ceramic substrate is, the less heat transfer from the electrode portion of the thermoelectric element to the cold-side heat sink or the hot-side heat sink is likely to be. Therefore, if the heat sink having a thinner thickness while performing the heat transfer function and the insulation function is used, the efficiency of the thermoelectric element can be improved.

As an example of the heat sink of the present invention, a metal material having a strength higher than that of the ceramic may be considered. If the metal of the same material as the cold-side heat sink or the hot-side heat sink is used, the thermal resistance generated between the metals of different materials can be reduced. If the cold-side heat sink or the hot-side heat sink is designed with an aluminum material, an aluminum material may also be suitable for the heat sink. The aluminum material has excellent thermal conductivity, about 10 times that of the ceramic. In addition, the aluminum material is also more excellent in an insulating function than iron forming a case of the refrigerator.

On the other hand, in the case of a normal thermoelectric element, a sealing material is bonded and sealed between the side surface portion of the heat absorption side ceramic substrate and the side surface portion of the heat generation side ceramic substrate, thereby preventing foreign substances from flowing into the semiconductor portion of the thermoelectric element.

With the above configuration, another heat conduction path is formed at a position adjacent to the heat absorbing surface and the heat generating surface of the thermoelectric element, whereby heat can be transferred through the sealing material, whereby the efficiency of the thermoelectric element can be reduced.

Therefore, it is possible to be advantageous to dispose the sealing material at a position spaced as far as possible from the heat absorbing surface and the heat generating surface of the thermoelectric element. The sealing cap 26 according to the present invention is disposed in a state of being spaced apart from the thermoelectric element, and is configured to connect and seal the cold-side heat sink 22 and the hot-side heat sink 24, so that the efficiency of the thermoelectric element can be improved.

In addition, the case where the sealing cap is bonded between the cold-side heat sink and the hot-side heat sink can improve the convenience of operation, compared to the case where a sealing material is bonded between the heat absorbing surface and the heat generating surface of the thermoelectric element.

< second embodiment >

Fig. 9 is a sectional view of a thermoelectric module according to a second embodiment of the present invention.

Referring to fig. 9, a thermoelectric module 20a of a second embodiment of the present invention has the following structure: two thermoelectric elements 40a, 40b are arranged between the cold-side heat sink 22 and the hot-side heat sink 24, the two thermoelectric elements 40a, 40b being divided by the heat transfer block 27.

In addition, in the thermoelectric module 20a of the present embodiment, the sealing cover 26 surrounds the edges of the cold-side heat sink 22 and the hot-side heat sink 24, thereby blocking foreign substances from flowing into the inside of the thermoelectric module 20a, as in the thermoelectric module 20 of the first embodiment.

In addition, as in the thermoelectric module 20 of the first embodiment, a ceramic substrate is replaced with a fin portion.

In detail, the two thermoelectric elements for constituting the thermoelectric module 20a of the second embodiment may include a first thermoelectric element 40a and a second thermoelectric element 40b, and the first thermoelectric element 40a and the second thermoelectric element 40b constitute the same structure.

Since the heat absorbing surface of the first thermoelectric element 40a is attached to the cold-side radiator 22 to absorb heat, it may be defined as a heat-absorbing-side thermoelectric element 40 a.

Since the heat generating surface of the second thermoelectric element 40b is attached to the hot-side radiator 24 and releases the heat transferred via the heat-absorbing-side thermoelectric element 40a to the hot-side radiator 24, it can be defined as a heat-generating-side thermoelectric element 40 b.

As described above, a thermoelectric module that can be used to connect two thermoelectric elements in a heat-transferable manner is defined as a cascade-type thermoelectric element or a thermoelectric module. A cascaded thermoelectric element can be understood as the following structure: the heat generating surface of the first thermoelectric element and the heat absorbing surface of the second thermoelectric element are connected in a heat-exchangeable manner, the cold-side heat sink is connected in a heat-transferable manner to the heat absorbing surface of the first thermoelectric element, and the hot-side heat sink is connected in a heat-transferable manner to the heat generating surface of the second thermoelectric element.

The technical meaning of the installation of the heat transfer block 27 can be explained in various aspects as follows.

The heat transfer block 27 may be disposed between the heat emitting surface of the first thermoelectric element 40a and the heat absorbing surface of the second thermoelectric element 40 b.

On the other hand, one surface of the heat transfer block 27 may be coupled to the heat generating surface of the first thermoelectric element 40a, and the other surface of the heat transfer block 27 may be coupled to the heat absorbing surface of the second thermoelectric element 40 b.

In order to reduce the backflow of heat between the heat emitting surface of the first thermoelectric element 40a and the heat absorbing surface of the second thermoelectric element 40b, the heat transfer block 27 may be disposed between the heat emitting surface of the first thermoelectric element 40a and the heat absorbing surface of the second thermoelectric element 40 b.

The heat transfer block 27 may perform: a function of a heat transfer path formed between the heat emitting surface of the first thermoelectric element 40a and the heat absorbing surface of the second thermoelectric element 40 b.

Without the heat transfer path, the heat transferred from the cold-side heat sink 22 may be retained between the heat generating surface of the first thermoelectric element 40a and the heat absorbing surface of the second thermoelectric element 40b, and may not flow to the hot-side heat sink 24.

Without the heat transfer path, heat transferred from the cold side heat sink 22 may flow back and not flow to the hot side heat sink 24. However, there may occur a disadvantage that the thermal resistance becomes larger as the longitudinal sectional area of the heat transfer passage, which may be defined by the size of the surface intersecting the heat flow direction, that is, the thickness of the heat transfer block is larger. In addition, the greater the length or width of the heat transfer block, the less the thermal resistance may be. Here, the length or width of the heat transfer block may be defined as a length extending in a direction crossing the thickness t of the heat transfer block. For example, the length of the heat transfer block may be defined as a length extending in an x-axis direction, the width of the heat transfer block may be defined on the same plane as the x-axis, and may be defined as a length extending in a y-axis direction crossing the x-axis, and the thickness t of the heat transfer block may be defined as a length extending in a z-axis direction crossing the x-axis and the y-axis.

Each of the two thermoelectric elements 40a, 40b may comprise: a semiconductor element section including P-type semiconductors 41a, 41b and N-type semiconductors 42a, 42 b; and an electrode portion including the heat absorption-side electrodes 43a, 43b and the heat generation-side electrodes 44a, 44 b.

The thickness of the heat transfer block 27 may be larger than the thickness of the electrode portions of the thermoelectric elements 40a and 40 b. The thickness of the heat transfer block 27 may be smaller than the thickness of the semiconductor element portion of the thermoelectric element. The thickness of the heat transfer block may be smaller than the thickness of the semiconductor element portion of the first thermoelectric element 40a and the thickness of the semiconductor element portion of the second thermoelectric element 40 b.

The length of the heat transfer block 27 may be set to be greater than the length of the electrode portions of the thermoelectric elements 40a and 40 b. The length of the heat transfer block 27 may be set to be greater than the length of the semiconductor element portion of the thermoelectric element.

The heat-absorbing-side heat-electric element 40a may include a pair of heat-absorbing-side fins 45a, and the heat-generating-side heat-electric element 40b may include a pair of heat-generating-side fins 45 b.

The pair of heat absorption side fins 45a may include: a first heat sink sandwiched between the heat absorption-side electrode 43a and the cold-side heat sink 22; and a second heat sink interposed between the heat-generating-side electrode 44a and the heat transfer block 27.

The pair of heat generation-side fins 45b may include: a third heat sink interposed between the heat transfer block 27 and the heat absorption-side electrode 43 b; and a fourth heat dissipation sheet interposed between the heat generation-side electrode 44b and the hot-side heat sink 24.

The fin portion may be understood as an insulating heat transfer sheet capable of only heat transfer while preventing current from flowing through the cold side heat sink 22 and the hot side heat sink 24.

On the other hand, the heat transfer block 27 may include a non-electrically conductive metal block (non-electrically conductive metal block) having a large heat transfer coefficient, and may include a plate-shaped aluminum block, for example.

In addition, the heat sinks 45a, 45b may be adhered to the cold-side heat sink 22, the hot-side heat sink 24, and the heat transfer block 27, respectively, by thermally conductive silicone grease.

According to the present embodiment, at least two thermoelectric elements are disposed between the cold-side radiator 22 and the hot-side radiator 24, thereby dividing a temperature difference Δ T between a heat absorbing surface of the thermoelectric module 20a that exchanges heat with the cold-side radiator 22 and a heat generating surface of the thermoelectric module 20a that exchanges heat with the hot-side radiator 24 into a first temperature difference Δ T1 and a second temperature difference Δ T2.

In detail, in order to realize the required heat absorption by one thermoelectric elementThe temperature difference DeltaT between the surface and the heat generating surface increases the power consumption for driving the thermoelectric element and decreases the cooling capacity Q of the thermoelectric element_cAs a result, the efficiency of the thermoelectric element is lowered.

In order to minimize this problem, two thermoelectric elements 40a and 40b having a small temperature difference Δ T between the heat absorbing surface and the heat generating surface are disposed between the hot-side heat sink and the cold-side heat sink, whereby the temperature of the storage chamber (for example, a deep freezing chamber) cooled by the cold-side heat sink 22 can be cooled to a desired temperature, and power consumption can be reduced.

For example, in the case of a thermoelectric module including a hot-side radiator 24 through which a refrigerant of about-20 ℃ flows and a single thermoelectric element, in order to cool the deep freezing chamber to-50 ℃, a thermoelectric element having a temperature difference Δ T between a heat absorbing surface and a heat generating surface of 30 ℃ is required.

In order to cool the temperature of the deep freezing chamber to a set temperature using such a thermoelectric module, it is necessary to design to apply a voltage of about 18V to the thermoelectric element. Further, since the temperature difference is large, the cooling capacity and efficiency are inevitably lowered in consideration of the characteristics of the thermoelectric element.

However, if the cascade thermoelectric element is configured by connecting two thermoelectric elements having a specification in which the temperature difference Δ T between the heat absorption/generation surfaces is less than 30 ℃, there is an effect of improving the cooling capacity and efficiency of the thermoelectric module while maintaining the temperature difference between the hot-side heat sink and the cold-side heat sink at 30 ℃.

There may be no large difference between the magnitude of the voltage applied to each of the two thermoelectric elements and the magnitude of the voltage applied to the thermoelectric module composed of the single thermoelectric element. However, if the time required to lower the temperature of the heat absorbing surface of the thermoelectric module to the set temperature and the time required to lower the temperature of the deep freezing chamber to the set temperature are compared, the time elapsed when the cascade-type thermoelectric module is applied is shorter than the time elapsed when the thermoelectric module composed of a single thermoelectric element is applied. Therefore, it can be said that the cooling capacity of the cascade-type thermoelectric module is improved, and the power consumption is reduced, thereby improving the efficiency of the thermoelectric module.

On the other hand, the performance of the cascaded thermoelectric module becomes different according to the magnitude of the voltage applied to each of the two thermoelectric elements.

Specifically, the two thermoelectric elements may be the thermoelectric elements of the same specification in which the temperature difference Δ T1 between the heat absorbing surface and the heat generating surface of the first thermoelectric element 40a and the temperature difference Δ T2 between the heat absorbing surface and the heat generating surface of the second thermoelectric element 40b have the same value, or the thermoelectric elements of different specifications in which the temperature difference is different from each other.

In the case where the amounts of electric currents supplied to the two thermoelectric elements are made the same and the thermoelectric elements of specifications different in temperature difference from each other are applied, it is preferable that the temperature difference Δ T2 of the second thermoelectric element 40b is made smaller than the temperature difference Δ T1 of the first thermoelectric element 40 a.

In detail, since the cooling capacity of the thermoelectric element is larger as the temperature difference Δ T is smaller, it may be advantageous to arrange the thermoelectric element having the smaller temperature difference Δ T on the hot-side heat sink 24 side when the same current is supplied.

Cooling capability Q of thermoelectric element according to the above description_cThe smaller the temperature difference, the greater the cooling capacity of the thermoelectric element may be.

In other words, the cooling capacity of the second thermoelectric element 40b can be made larger than that of the first thermoelectric element 40a, so that the heat Q transferred to the heat generating surface of the first thermoelectric element 40a can be absorbed in the whole of the heat absorbing surface of the second thermoelectric element 40b_outAnd thus to the heat-side radiator 24 side.

If the heat absorbing surface of the second thermoelectric element 40b cannot absorb all of the heat transferred from the heat generating surface of the first thermoelectric element 40a, there is a possibility that the efficiency of the thermoelectric module 20a is lowered.

For reference, the heat Q emitted from the heat generating surface of the first thermoelectric element 40a_outCan be defined as the amount of heat Q absorbed via the cold-side heat sink 22_cAnd the amount of electricity P supplied to the first thermoelectric element 40a_eAnd the unit thereof may beExpressed in J (Joule) or Kcal.

Conversely, when the temperature difference specifications of the first thermoelectric element 40a and the second thermoelectric element 40b are set to be the sameThe amount of current (or voltage difference) supplied to the first thermoelectric element 40a and the second thermoelectric element 40b is controlled to be different, thereby enabling the efficiency of the thermoelectric module 20a to be improved to the maximum.

First, a case where the same voltage is applied to the first thermoelectric element 40a and the second thermoelectric element 40b will be described. The same magnitude voltage may be any one of the same high voltage, the same medium voltage, and the same low voltage.

When an arbitrary voltage Va is supplied to the first thermoelectric element 40a, the heat (Q) emitted from the heat generating surface of the first thermoelectric element 40a_out1) As follows.

Q_out1＝Q_c1+Pe₁

When an arbitrary voltage Va is supplied to the first thermoelectric element 40a and the second thermoelectric element 40b, heat (Q) to be released from the hot-side heat sink 24 attached to the heat generating surface of the second thermoelectric element 40b is required_out2) As follows.

Q_out2＝Q_out1+Pe₂，

Pe₂: amount of electricity supplied to the second thermoelectric element 40b

Here, in the case where the hot-side radiator 24 is an evaporator through which refrigerant passing through a freezing chamber expansion valve flows, the surface temperature of the hot-side radiator 24 is maintained substantially at a temperature in the range of-25 ℃ to-30 ℃.

In this case, the following problems occur: in order for the hot-side heat sink 24 to quickly absorb the heat (Q)_out2) It is necessary to further reduce the temperature of the refrigerant passing through the hot-side radiator 24, or to design the hot-side radiator 24 to be very large. That is, when the same voltage is applied to the two thermoelectric elements, the heat radiation from the cold side cannot be quickly released by the hot side heat sink 24The side of the vessel 22 absorbs the heat received.

On the other hand, in the case where the hot-side heat sink 24 is designed to be very large, there may occur a disadvantage that the volume of the storage chamber of the refrigerator is relatively reduced.

In addition, in order to further reduce the temperature of the refrigerant passing through the hot-side radiator 24, there may arise a difficulty in that a new refrigerant having higher efficiency than the current refrigerant needs to be developed.

In addition, in order to further lower the temperature of the refrigerant passing through the hot-side radiator 24, there may occur a disadvantage that components of a refrigerant cycle system of a compressor, a condenser, and the like of a refrigerator need to be designed more. Thereby, a disadvantage may occur in that the volume of the storage chamber of the refrigerator is further reduced.

Therefore, the consumed power increases, and the cooling capacity of the thermoelectric module 20a decreases, eventually resulting in a decrease in the efficiency of the thermoelectric module 20 a.

In the case where the voltage applied to the first thermoelectric element 40a is higher than the voltage applied to the second thermoelectric element 40b, the heat absorbing surface of the second thermoelectric element 40b cannot absorb all the heat emitted through the heat generating surface of the first thermoelectric element 40a, and therefore, the efficiency of the thermoelectric module 20a is further lowered.

In contrast, in the case where the voltage applied to the second thermoelectric element 40b is greater than the voltage applied to the first thermoelectric element 40a, the heat absorbed through the heat absorbing surface of the first thermoelectric element 40a may be entirely absorbed by the second thermoelectric element 40b and may be released to the outside of the thermoelectric module 20a through the hot-side heat sink 24.

In particular, it is very advantageous to improve the efficiency of the thermoelectric module 20a in that either a medium voltage or a low voltage is applied to the first thermoelectric element 40a when a high voltage is applied to the second thermoelectric element 40b, and a low voltage is applied to the first thermoelectric element 40a when a medium voltage is applied to the second thermoelectric element 40 b.

It should be understood that the power control or the voltage control of the cascade thermoelectric module including two thermoelectric elements described above is also applicable to the cascade thermoelectric modules of the third embodiment and the fourth embodiment described below.

The thermoelectric module of the present invention may include: a cold-side heat sink 22; a first thermoelectric element 40a, the heat absorbing surface of which is connected to the cold-side heat sink 22; a second thermoelectric element 40b having a heat absorbing surface connected to the heat generating surface of the first thermoelectric element 40 a; and a hot-side heat sink 24 connected to a heat generating surface of the second thermoelectric element 40b, thereby releasing heat transferred from the cold-side heat sink 22 to the outside.

The first thermoelectric element 40a may include: a semiconductor element section including a P-type semiconductor and an N-type semiconductor; a heat absorption side electrode portion 44a formed at one end of the semiconductor element portion and connected to the cold-side heat sink 22; and a heat-generating-side electrode portion 43a formed at the other end of the semiconductor element portion and connected to the heat-absorbing surface of the second thermoelectric element 40 b.

The second thermoelectric element 40b may include: a semiconductor element section including a P-type semiconductor and an N-type semiconductor; a heat absorption side electrode portion 44b formed at one end of the semiconductor element portion and connected to the heat generation surface of the first thermoelectric element 40 a; and a heat-generating-side electrode portion 43b formed at the other end of the semiconductor element portion and connected to the hot-side heat sink 24.

The thermoelectric module may further include a sealing cover connecting an edge of the cold-side heat sink and an edge of the hot-side heat sink.

This configuration can improve the convenience of operation.

The sealing cap may be configured to seal the edges of the cold side heat sink 22 and the hot side heat sink 24. This configuration can prevent foreign matter from flowing into the thermoelectric element.

The sealing cover may be disposed in a state of being spaced apart from the first thermoelectric element 40a and the second thermoelectric element 40 b. This configuration can increase the heat transfer efficiency of the thermoelectric module.

The thermoelectric module may further include: a first heat sink 45a connected between the cold-side heat sink 22 and the heat-absorption-side electrode portion of the first thermoelectric element 40 a; and a second heat sink 45b connected between the hot-side heat sink 24 and the heat-generating-side electrode portion of the second thermoelectric element 40 b.

The first and second heat radiating fins 45a and 45b may perform a heat transfer function and an insulation function.

The thermoelectric module may further include a heat transfer block 27, the heat transfer block 27 being sandwiched between the first thermoelectric element 40a and the second thermoelectric element 40 b.

The heat absorption-side electrode portion of the first thermoelectric element 40a may be attached to the cold-side heat sink, and the heat generation-side electrode portion of the second thermoelectric element 40b may be attached to the hot-side heat sink 24.

The heat-generating-side electrode portion of the first thermoelectric element 40a may be attached to one surface of the heat transfer block 27, and the heat-absorbing-side electrode portion of the second thermoelectric element 40b may be attached to the other surface of the heat transfer block 27.

The heat transfer block 27 can reduce a phenomenon that heat transferred from the cold-side heat sink 22 flows back to the hot-side heat sink 24 without flowing.

The control unit may control to apply any one of a high voltage and a low voltage lower than the high voltage to the first thermoelectric element 40a and the second thermoelectric element 40 b.

The control unit may control the voltage applied to the second thermoelectric element 40b to be greater than the voltage applied to the first thermoelectric element 40 a. This configuration can reduce not only the increase in the size of the hot-side heat sink 24 but also the increase in the size of the device for cooling the hot-side heat sink 24.

This can reduce the increase in the volume of the evaporator chamber of the refrigerator, and as a result, can increase the volume of the storage chamber of the refrigerator.

A temperature difference Δ T1 between the heat absorbing surface and the heat generating surface of the first thermoelectric element may be equal to or greater than a temperature difference Δ T2 between the heat absorbing surface and the heat generating surface of the second thermoelectric element. This is because it is advantageous to design the cooling capacity of the thermoelectric element adjacent to the hot-side heat sink to be large.

< third embodiment >

Fig. 10 is a sectional view of a thermoelectric module according to a third embodiment of the present invention.

Referring to fig. 10, in a thermoelectric module 20b according to a third embodiment of the present invention, the same idea is applied to dispose two thermoelectric modules 51 and 52 between a cold-side heat sink 22 and a hot-side heat sink 24, as in the second embodiment. However, the two thermoelectric modules 51 and 52 have slightly different configurations.

In detail, the thermoelectric module 20b of the third embodiment may include: a cold-side heat sink 22; a first thermoelectric element 51 with its heat absorbing surface attached to the cold-side heat sink 22; a second thermoelectric element 52 having a heat absorbing surface connected to the heat generating surface of the first thermoelectric element 51 so as to be thermally conductive; a hot-side heat sink 24 attached to the heat generating surface of the second thermoelectric element 52; and an intermediate substrate 53 interposed between the first thermoelectric element 51 and the second thermoelectric element 52 at the joint portion.

In more detail, the first thermoelectric element 51 may include a semiconductor element portion, an electrode portion, a heat absorption side substrate 515, and a sealing member 516.

The semiconductor element portion includes a P-type semiconductor element 511 and an N-type semiconductor element 512.

The electrode section includes: a heat absorption side electrode 513 provided at one end of the semiconductor element portion; and a heat generation-side electrode 514 provided at the other end of the semiconductor element portion.

One surface of the heat absorption-side substrate 515 is attached to the cold-side heat sink 22 by thermal grease (thermal grease)517, and the heat absorption-side electrode 513 is formed on the other surface thereof.

In addition, the sealing member 516 is surrounded by the edges of the heat absorption side substrate 515 and the intermediate substrate 53.

The second thermoelectric element 52 includes a semiconductor element portion, an electrode portion, a heat-generating-side substrate 525, and a sealing member 526.

The semiconductor element section includes a P-type semiconductor element 521 and an N-type semiconductor element 522.

The electrode section includes: a heat absorption side electrode 523 provided at one end of the semiconductor element portion; and a heat generation-side electrode 524 provided at the other end of the semiconductor element portion.

One surface of the heat-generating side substrate 525 is attached to the hot-side heat sink 24 through thermal grease (thermal grease)54, and the other surface is formed with the heat-generating side electrode 525.

In addition, the sealing member 526 is surrounded by the edges of the heat generation side substrate 525 and the intermediate substrate 53.

The heat-generating-side electrode 514 of the first thermoelectric element 51 is formed on one surface of the intermediate substrate 53, and the heat-absorbing-side electrode 523 of the second thermoelectric element 52 is formed on the other surface thereof.

The heat absorption-side substrate 515, the heat generation-side substrate 525, and the intermediate substrate 53 may be substrates of a ceramic material, as in the thermoelectric element of the related art. The sealing members 516 and 526 may be sealing members of a conventional thermoelectric element, and prevent foreign substances from entering the thermoelectric element by connecting the edges of the ceramic substrate.

According to the present embodiment, although the structure in which two conventional thermoelectric elements are connected is adopted, the single intermediate substrate 53 is bonded to the joint portion of the two thermoelectric elements.

< fourth embodiment >

Fig. 11 is a sectional view of a thermoelectric module according to a fourth embodiment of the present invention.

Referring to fig. 11, a thermoelectric module 20c of a fourth embodiment of the present invention has the same structure as the thermoelectric module 20b of the third embodiment, except for a difference in the aspect of applying two intermediate substrates.

In detail, in the thermoelectric module 20c of the fourth embodiment, the first and second thermoelectric elements 53 and 53 are attached to each other through the heat conductive silicone grease 54, and are attached to the cold-side heat sink 22 and the hot-side heat sink 24.

The first thermoelectric element 53 and the second thermoelectric element 54 have the same structure as the thermoelectric element structure of the related art.

The first thermoelectric element 53 includes a heat absorption side substrate 535, a heat generation side substrate 536, a semiconductor element portion including a P-type semiconductor element 531 and an N-type semiconductor element 532, an electrode portion, and a sealing member 537.

The electrode section includes: a heat absorption side electrode 533 formed between one end of the semiconductor element portion and the heat absorption side substrate 535; and a heat generation side electrode 534 formed between the other end portion of the semiconductor element portion and the heat generation side substrate 536. The second thermoelectric element 53 has the same structure as the first thermoelectric element 53, and thus, a repetitive description thereof will be omitted.

The heat-generating-side substrate 536 of the first thermoelectric element 53 is attached to the heat-absorbing-side substrate of the second thermoelectric element 54 via the heat conductive silicone grease 54.

The heat absorption side substrate 535 of the first thermoelectric element is bonded to the cold side heat sink 22 by a thermally conductive silicone grease 54.

The heat-generating side substrate of the second thermoelectric element is bonded to the hot-side heat sink 24 by a heat-conductive silicone grease 54.

In addition, edges of the heat absorption side substrate 535 and the heat generation side substrate 536 constituting the first thermoelectric element 53 are connected by the sealing member 537, thereby isolating a space for accommodating the semiconductor element portion from the outside. The same applies to the second thermoelectric element 54.

< fifth embodiment >

Fig. 12 is a longitudinal sectional view of a thermoelectric module according to a fifth embodiment of the present invention.

Referring to fig. 12, the thermoelectric module 20d of the fifth embodiment has substantially the same structure as the thermoelectric module 20 of the first embodiment shown in fig. 8, but differs in the following portions.

First, heat transfer blocks 27 are interposed between the heat absorption side fins 45 and the cold side heat sink 22, and between the heat generation side fins 46 and the hot side heat sink 24, respectively, and the plurality of heat transfer blocks 27 are fixed to the cold side heat sink 22 and the hot side heat sink 24, respectively, by heat conductive silicone grease 54.

Second, both ends of the sealing cover 26 are connected to the side surfaces of the two heat transfer blocks 27, respectively, thereby preventing foreign substances from flowing into the thermoelectric elements.

Here, an insulating material 23 is interposed between the cold-side heat sink 22 and the hot-side heat sink 24, thereby preventing heat from being transferred from the hot-side heat sink 24 to the cold-side heat sink 22.

The thermoelectric element 40 of the present embodiment is the same in configuration as the thermoelectric element 40 of the first embodiment, and therefore, a repetitive description will be omitted.

< sixth embodiment >

Fig. 13 is a longitudinal sectional view of a thermoelectric module according to a sixth embodiment of the present invention.

Referring to fig. 13, a thermoelectric module 20e according to a sixth embodiment of the present invention is identical in configuration to the thermoelectric module 20a according to the second embodiment shown in fig. 9, but differs in the following portions.

First, heat transfer blocks 27 are interposed between the cold-side radiator 22 and the first thermoelectric element 40a and between the hot-side radiator 24 and the second thermoelectric element 40b, respectively, and the heat transfer blocks 27 may be fixed to the cold-side radiator 22 and the hot-side radiator 24, respectively, by heat conductive silicone grease 54.

Therefore, the thermoelectric module 20e of the sixth embodiment is different from the thermoelectric module 20a of the second embodiment in that three heat transfer blocks 27 are provided in total.

Here, a heat transfer block (block) attached to the cold-side heatsink 22 may be defined as a first heat transfer block, a heat transfer block attached to the hot-side heatsink 24 may be defined as a second heat transfer block, and a heat transfer block sandwiched between the first thermoelectric element 40a and the second thermoelectric element 40b may be defined as a third heat transfer block.

Second, both end portions of the seal cover 26 are coupled to the side surfaces of the first heat transfer block and the second heat transfer block, respectively, which can be said to be substantially the same as the structure of the seal cover 26 explained in the fifth embodiment.

In the sixth embodiment, as in the fifth embodiment, an insulating material 23 may be interposed between the cold-side heat sink 22 and the hot-side heat sink 24, thereby preventing heat from flowing back from the hot-side heat sink 24 to the cold-side heat sink 22.

In summary, the tandem thermoelectric modules disclosed in the second to fourth embodiments and the sixth embodiment have the following common features.

First, a first thermoelectric element and a second thermoelectric element are included.

Secondly, the heat absorbing surface of the first thermoelectric element is connected with the cold-side radiator in a heat conduction manner, and the heat generating surface of the second thermoelectric element is connected with the hot-side radiator in a heat conduction manner.

Thirdly, the heat emitting surface of the first thermoelectric element is connected with the heat absorbing surface of the second thermoelectric element in a heat conducting manner.

Fourth, the voltage applied to the first thermoelectric element and the voltage applied to the second thermoelectric element may have different magnitudes. Specifically, the voltage applied to the second thermoelectric element may be greater than the voltage applied to the first thermoelectric element.

Fifth, the space between the ceramic substrates is shielded or sealed from the external space by a sealing member, or the space between the cold-side heat sink and the hot-side heat sink is shielded or sealed from the external space by a sealing cover.

In addition, the thermoelectric modules according to the first to sixth embodiments have common features as described below.

That is, both end portions of the semiconductor element portion are soldered to the heat sink or the substrate of the ceramic material through the electrode portion of the copper material, and a gold plating layer of gold (Au) material is formed at the electrode portion, whereby solder wetting is improved, and soldering stability of the semiconductor element portion is improved.