阅读说明：本技术 基于氮化硼和碲化铋纳米复合材料的太阳能温差电池系统及其制作方法 (Solar thermoelectric cell system based on boron nitride and bismuth telluride nano composite material and manufacturing method thereof ) 是由 李玲 蒋祥倩 李涵 施宁强 于 2021-03-24 设计创作，主要内容包括：本发明公开了一种基于氮化硼和碲化铋纳米复合材料的太阳能温差电池系统及其制作方法,所述太阳能温差电池系统包括集热平台、导热铜管、散热模块、温差电池模块和太阳能电池,其中：所述导热铜管的中段位于集热平台的空槽内；所述太阳能电池固定在集热平台正上方的凹槽位置；所述导热铜管的两端弯曲成近90°在集热平台下方作为支撑；所述温差电池模块的热端面固定在导热铜管两端的侧面；所述散热模块固定在温差电池模块的冷端面处。本发明制备的太阳能温差电池系统提升了太阳能电池的发电效率以及寿命,方法工艺简单易行,所用设备简单、廉价,实验以及测试过程方便。(The invention discloses a solar thermoelectric cell system based on boron nitride and bismuth telluride nano composite materials and a manufacturing method thereof, wherein the solar thermoelectric cell system comprises a heat collection platform, a heat conduction copper pipe, a heat dissipation module, a thermoelectric cell module and a solar cell, wherein: the middle section of the heat conduction copper pipe is positioned in the empty groove of the heat collection platform; the solar cell is fixed at the position of the groove right above the heat collection platform; two ends of the heat conducting copper pipe are bent to be approximately 90 degrees and are used as supports below the heat collecting platform; the hot end surfaces of the thermoelectric cell modules are fixed on the side surfaces of the two ends of the heat conducting copper pipe; the heat dissipation module is fixed at the cold end face of the thermoelectric cell module. The solar thermoelectric cell system prepared by the invention improves the power generation efficiency and the service life of the solar cell, and the method has the advantages of simple and feasible process, simple and cheap used equipment and convenient experiment and test process.)

1. The utility model provides a solar energy thermoelectric cell system based on boron nitride and bismuth telluride nanocomposite which characterized in that solar energy thermoelectric cell system includes thermal-arrest platform, heat conduction copper pipe, heat dissipation module, thermoelectric cell module and solar cell, wherein:

a groove is formed right above the heat collection platform, and two lateral side faces of the heat collection platform are provided with empty grooves;

the middle section of the heat conduction copper pipe is positioned in the empty groove of the heat collection platform;

the solar cell is fixed at the position of the groove right above the heat collection platform;

two ends of the heat conducting copper pipe are bent to be approximately 90 degrees and are used as supports below the heat collecting platform;

the thermoelectric cell module comprises conductive copper sheets, P-type temperature difference unit crystal blocks and N-type temperature difference unit crystal blocks, wherein the conductive copper sheets are arranged on a cold surface and a hot surface at equal intervals;

the P-type temperature difference unit crystal block is made of P-type bismuth telluride and boron nitride aerogel;

the N-type temperature difference unit crystal block is made of N-type bismuth telluride and boron nitride aerogel;

the hot end surfaces of the thermoelectric cell modules are fixed on the side surfaces of the two ends of the heat conducting copper pipe;

the heat dissipation module is fixed at the cold end face of the thermoelectric cell module.

2. The solar thermoelectric cell system based on the boron nitride and bismuth telluride nanocomposite material as claimed in claim 1, wherein the heat collection platform is an aluminum alloy rectangular parallelepiped platform.

3. The solar thermoelectric cell system based on the boron nitride and bismuth telluride nanocomposite material as claimed in claim 1, wherein the conductive copper sheets are arranged in 6 rows, and 5 columns of conductive copper sheets are disposed in each row.

4. The solar thermoelectric cell system based on boron nitride and bismuth telluride nanocomposite material as claimed in claim 1, wherein the cold and hot surfaces are alumina ceramic plates.

5. A method for manufacturing a solar thermoelectric cell system based on a boron nitride and bismuth telluride nanocomposite material as claimed in any one of claims 1 to 4, wherein the method comprises the steps of:

step one, preparing a P-type temperature difference unit crystal block

(1) Weighing P-type bismuth telluride powder and boron nitride aerogel powder, and performing ball milling treatment to obtain the composite thermoelectric material of the P-type bismuth telluride and the boron nitride aerogel, wherein: the molar ratio of the P-type bismuth telluride to the boron nitride is 3-9: 10;

(2) carrying out hot pressing treatment on the P-type bismuth telluride and boron nitride aerogel composite thermoelectric material, and cutting and grinding the hot-pressed block body to obtain a P-type temperature difference unit crystal block;

step two, preparing an N-type temperature difference unit crystal block

(1) Weighing N-type bismuth telluride powder and boron nitride aerogel powder, and performing ball milling treatment to obtain the composite thermoelectric material of the N-type bismuth telluride and the boron nitride aerogel, wherein: the molar ratio of the N-type bismuth telluride to the boron nitride is 3-9: 10;

(2) carrying out hot pressing treatment on the N-type bismuth telluride and boron nitride aerogel composite thermoelectric material, and cutting and grinding the hot-pressed block body to obtain an N-type temperature difference unit crystal block;

step three, preparing a thermoelectric cell module

Connecting the P-type temperature difference unit crystal block and the N-type temperature difference unit crystal block by using a conductive copper sheet, conductive silver paste and high-temperature-resistant insulating heat-conducting adhesive to fix the P-type temperature difference unit crystal block and the N-type temperature difference unit crystal block on a cold surface and a hot surface to form a temperature difference battery module;

step four, preparing the solar thermoelectric cell system

The heat conduction copper pipe is placed at the empty groove of the heat collection platform, the two ends of the heat conduction copper pipe are bent, the surface of the heat conduction copper pipe, which is in contact with the heat collection platform, and the positions, which are close to the two ends, of the heat conduction copper pipe are flattened by the hot press, the thermoelectric cell module and the solar cell are fixed to the corresponding positions of the heat collection platform by the heat conduction silicone grease, and then the solar thermoelectric cell system is manufactured.

6. The method for manufacturing the solar thermoelectric cell system based on the boron nitride and bismuth telluride nanocomposite material according to claim 5, wherein in the first step, the ball milling speed is 200 rpm/min, and the ball milling time is 12-24 hours; the particle diameter of the mixed thermoelectric material of the P-type bismuth telluride and the boron nitride aerogel is 650-1440 nm; the pressure of the hot pressing treatment is 0.5-6 Mpa, the temperature is 300-350 ℃, and the time is 1-2 hours.

7. The manufacturing method of the solar thermoelectric cell system based on the boron nitride and bismuth telluride nanocomposite material as claimed in claim 5, wherein in the second step, the ball milling speed is 200 rpm/min, and the ball milling time is 12-24 hours; the particle diameter of the mixed thermoelectric material of the N-type bismuth telluride and the boron nitride aerogel is 650 nm-1440 nm; the pressure of the hot pressing treatment is 0.5-6 Mpa, the temperature is 300-350 ℃, and the time is 1-2 hours.

8. The method for manufacturing the solar thermoelectric cell system based on the boron nitride and bismuth telluride nanocomposite material as claimed in claim 5, wherein in the third step, gaps of the thermoelectric cell module are filled with boron nitride aerogel.

Technical Field

The invention belongs to the field of solar thermoelectric power generation, relates to a solar thermoelectric power generation system and a manufacturing method thereof, and particularly relates to a solar thermoelectric battery system formed by combining thermoelectric units formed by compounding boron nitride aerogel and bismuth telluride and a manufacturing method thereof.

Background

New challenges arise. Meanwhile, nearly 80% of solar energy irradiated radiation of a solar cell in the spacecraft is wasted into useless heat energy, the temperature of a solar PV panel is increased due to heat accumulation, the phenomena of yellowing, cracking and the like occur, the service life of the cell is shortened, and the output power of the cell is reduced. The solar temperature difference hybrid power generation system is an effective way for solving the problems. The thermoelectric cell based on the Seebeck effect has high requirements on ZT value of the material, the electric conductivity and the thermal conductivity of the traditional material are difficult to be adjusted, and the high ZT value thermoelectric material is difficult to find, so people increasingly try to prepare the composite crystal and try to optimize the thermoelectric property by utilizing different structures of the composite crystal, such as various filling Skutterite compounds and the like. Bismuth telluride is the most suitable material for thermoelectric power generation found at present, and how to further improve the ZT value of the bismuth telluride material becomes the focus of the current research. As a novel nano material, the boron nitride aerogel has the advantages of stable chemical property, small size, unique porous structure, large specific surface area, low thermal conductivity and the like, and the combination of the boron nitride aerogel and the bismuth telluride material can effectively reduce the thermal conductivity of the bismuth telluride material and improve the thermoelectric figure of merit of the bismuth telluride material.

Disclosure of Invention

In order to solve the problems of low solar power generation efficiency, short service life and the like, the invention provides a solar thermoelectric cell system based on a boron nitride and bismuth telluride nano composite material and a manufacturing method thereof. The solar thermoelectric cell system prepared by the invention improves the power generation efficiency and the service life of the solar cell, and the method has the advantages of simple and feasible process, simple and cheap used equipment and convenient experiment and test process.

The purpose of the invention is realized by the following technical scheme:

the utility model provides a solar energy thermoelectric cell system based on boron nitride and bismuth telluride nanocomposite, includes thermal-arrest platform, heat conduction copper pipe, heat dissipation module, thermoelectric cell module and solar cell, wherein:

a groove is formed right above the heat collection platform, and two lateral side faces of the heat collection platform are provided with empty grooves;

the middle section of the heat conduction copper pipe is positioned in the empty groove of the heat collection platform;

the solar cell is fixed at the position of the groove right above the heat collection platform;

two ends of the heat conducting copper pipe are bent to be approximately 90 degrees and are used as supports below the heat collecting platform;

the thermoelectric cell module comprises conductive copper sheets, P-type temperature difference unit crystal blocks and N-type temperature difference unit crystal blocks, wherein the conductive copper sheets are arranged on a cold surface and a hot surface at equal intervals;

the P-type temperature difference unit crystal block is made of P-type bismuth telluride and boron nitride aerogel;

the N-type temperature difference unit crystal block is made of N-type bismuth telluride and boron nitride aerogel;

the hot end surfaces of the thermoelectric cell modules are fixed on the side surfaces of the two ends of the heat conducting copper pipe;

the heat dissipation module is fixed at the cold end face of the thermoelectric cell module.

A manufacturing method of the solar thermoelectric cell system comprises the following steps:

step one, preparing a P-type temperature difference unit crystal block

(1) Weighing P-type bismuth telluride powder and boron nitride aerogel powder, and performing ball milling treatment to obtain a composite thermoelectric material of the P-type bismuth telluride and the boron nitride aerogel;

(2) carrying out hot pressing treatment on the P-type bismuth telluride and boron nitride aerogel composite thermoelectric material, and cutting and grinding the hot-pressed block body to obtain a P-type temperature difference unit crystal block;

in the step, the molar ratio of the P-type bismuth telluride to the boron nitride is 3-9: 10 (such as 3:10, 6:10 and 9: 10);

in the step, before ball milling treatment, the ball milling tank is vacuumized and injected with high-purity nitrogen to isolate external environmental pollution;

in the step, the ball milling speed is 200 rpm/min, and the ball milling time is 12-24 hours;

in the step, the particle diameter of the mixed thermoelectric material of the P-type bismuth telluride and the boron nitride aerogel is 650-1440 nm;

in the step, the mixed thermoelectric material of the P-type bismuth telluride and the boron nitride aerogel has lower thermal conductivity, and the thermal conductivity is only 0.067W/m.K;

in the step, the pressure of the hot pressing treatment is 0.5-6 Mpa, the temperature is 300-350 ℃, and the time is 1-2 hours;

step two, preparing an N-type temperature difference unit crystal block

(1) Weighing N-type bismuth telluride powder and boron nitride aerogel powder, and performing ball milling treatment to obtain a composite thermoelectric material of the N-type bismuth telluride and the boron nitride aerogel;

(2) carrying out hot pressing treatment on the N-type bismuth telluride and boron nitride aerogel composite thermoelectric material, and cutting and grinding the hot-pressed block body to obtain an N-type temperature difference unit crystal block;

in the step, the molar ratio of the N-type bismuth telluride to the boron nitride is 3-9: 10 (such as 3:10, 6:10 and 9: 10);

in the step, before ball milling treatment, the ball milling tank is vacuumized and injected with high-purity nitrogen to isolate external environmental pollution;

in the step, the ball milling speed is 200 rpm/min, and the ball milling time is 12-24 hours;

in the step, the particle diameter of the mixed thermoelectric material of the N-type bismuth telluride and the boron nitride aerogel is 650-1440 nm;

in the step, the mixed thermoelectric material of the N-type bismuth telluride and the boron nitride aerogel has lower thermal conductivity, and the thermal conductivity is only 0.067W/m.K;

in the step, the pressure of the hot pressing treatment is 0.5-6 Mpa, the temperature is 300-350 ℃, and the time is 1-2 hours;

step three, preparing a thermoelectric cell module

An alumina ceramic plate is used as a cold and hot surface of the thermoelectric cell, and a P-type thermoelectric unit crystal block and an N-type thermoelectric unit crystal block are connected and fixed on the alumina ceramic plate by using a conductive copper sheet, conductive silver paste and high-temperature-resistant insulating heat-conducting adhesive to form a thermoelectric cell module;

in the step, conductive copper sheets are arranged on an alumina ceramic plate coated with a layer of insulating high-temperature-resistant heat-conducting adhesive at equal intervals, the number of the conductive copper sheets is 6, and 5 columns of conductive copper sheets are arranged in each row; placing a pair of P-type and N-type temperature difference unit crystal blocks on each conductive copper sheet, connecting different types of crystal blocks on adjacent copper sheets by using conductive copper sheets, and connecting the conductive copper sheets and the crystal blocks by using conductive silver paste;

in the step, the gaps of the thermoelectric cell module are filled with boron nitride aerogel;

step four, preparing the solar thermoelectric cell system

The heat conduction copper pipe is placed at the empty groove of the heat collection platform, the two ends of the heat conduction copper pipe are bent, the surface of the heat conduction copper pipe, which is in contact with the heat collection platform, and the positions, which are close to the two ends, of the heat conduction copper pipe are flattened by the hot press, the thermoelectric cell module and the solar cell are fixed to the corresponding positions of the heat collection platform by the heat conduction silicone grease, and then the solar thermoelectric cell system is manufactured.

Compared with the prior art, the invention has the following advantages:

1. the bismuth telluride and boron nitride aerogel nano composite unit crystal block prepared by the method has ultralow heat conductivity and relatively high power factor, and the boron nitride aerogel is used for filling the internal space of the nano composite unit crystal block, so that the heat transmission of a cold end and a hot end can be further prevented, the temperature difference of the cold end and the hot end can be expanded, and the output power of a thermoelectric cell can be improved.

2. The method provided by the invention is simple and feasible in process, the used equipment is the existing laboratory instrument equipment, the experimental process is more convenient, and the manufactured solar thermoelectric power generation system has a wide prospect in the field of solar thermoelectric power generation.

Drawings

FIG. 1 is a design diagram of a solar thermoelectric cell system based on boron nitride and bismuth telluride nano composite materials, 1-a solar cell, 2-a heat collection platform, 3-a heat conduction copper pipe, 4-a thermoelectric cell and 5-a heat dissipation module;

FIG. 2 is a diagram of a solar thermoelectric cell system based on boron nitride and bismuth telluride nanocomposite;

FIG. 3 is an SEM image of a bismuth telluride and boron nitride aerogel mixed powder prepared in example 1 after ball milling;

FIG. 4 is an EDS diagram of a bismuth telluride and boron nitride aerogel mixed powder prepared in example 1 after ball milling;

FIG. 5 is a block of a bismuth telluride and boron nitride aerogel mixed thermoelectric material obtained by hot pressing in example 1;

FIG. 6 is a graph of the thermal conductivity of the boron nitride aerogel prepared in example 1 and of a composite thermoelectric material;

FIG. 7 is a thermoelectric unit cell module prepared in example 1;

FIG. 8 is an assembly view of the heat collecting platform and the heat pipe manufactured in example 1;

fig. 9 is a solar thermoelectric cell system fabricated in example 1;

fig. 10 is a graph showing a power test result of the solar thermoelectric cell system manufactured in example 1.

Detailed Description

The technical solutions of the present invention are further described below with reference to the following examples, but the present invention is not limited thereto, and any modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Example 1:

in this embodiment, the manufacturing method of the solar thermoelectric cell power generation system is as follows:

the method comprises the following steps: respectively weighing 30g of P-type bismuth telluride powder and N-type bismuth telluride powder by using an electronic balance, putting the P-type bismuth telluride powder and the N-type bismuth telluride powder into two ball milling tanks, weighing two parts of 3g of boron nitride aerogel powder, and respectively putting the boron nitride aerogel powder into the powder, wherein the weight ratio of BN: bi₂Te₃In a molar ratio of 10: 6. vacuumizing the ball milling tank, injecting high-purity nitrogen, placing the ball milling tank in a horizontal planetary ball mill for continuous ball milling for 12 hours at the rotating speed of 200 rpm/min to reduce the size of the nano particles of the bismuth telluride and boron nitride powder andand fully mixing the two kinds of powder to obtain the P-type and N-type composite thermoelectric materials of bismuth telluride and boron nitride aerogel.

Step two: and (3) respectively putting the two composite thermoelectric materials of bismuth telluride aerogel and boron nitride aerogel obtained in the step one into a hot-pressing die, and hot-pressing for 1h under the conditions that the pressure of a hot press is 3MPa and the temperature is 350 ℃. And after the hot pressing is finished, taking down the die, and cutting and grinding the block obtained after the hot pressing to obtain the temperature difference unit crystal block with the size of 1.4mm multiplied by 1.7 mm.

Step three: an alumina ceramic plate with the size of 20mm multiplied by 30mm multiplied by 0.6mm is used as the cold and hot surfaces of the thermoelectric cell, small copper sheets with the size of 4mm multiplied by 1.6mm multiplied by 0.3mm are arranged on the alumina ceramic plate coated with a layer of insulating heat-conducting glue at equal intervals, 6 rows are arranged in total, and 5 rows of copper sheets are arranged in each row. A pair of (P type and N type) unit crystal blocks are placed on each small copper sheet, the size of each crystal block is 1.4mm multiplied by 1.7mm, different types of crystal blocks on adjacent copper sheets are connected through the copper sheets, the copper sheets are connected with the crystal blocks through conductive silver paste, boron nitride aerogel with the heat conductivity coefficient of 0.02W/m.k is filled in gaps of devices, the filling rate is 50%, and the whole thermoelectric cell module is packaged.

Step four: an aluminum alloy cuboid platform of 49mm multiplied by 35mm multiplied by 4mm is customized, and a groove of 40mm multiplied by 35mm multiplied by 3mm is reserved right above the cuboid platform. The heat conduction copper pipe is placed at the empty groove of the heat collection platform, the surface of the heat conduction copper pipe, which is in contact with the heat collection platform, and the positions, which are close to two ends, of the heat conduction copper pipe are flattened by a hot press to place the thermoelectric cell module, and the copper pipe is bent into an arc shape of nearly 90 degrees. Then the solar cell and the thermoelectric cell module are fixed at corresponding positions of the device through the heat-conducting silicone grease, and finally the exposed part of the device in the air is packaged by heat-insulating cotton (as shown in figures 1 and 2).

Fig. 3 is an SEM image of the bismuth telluride and boron nitride aerogel mixed powder prepared in this example after ball milling; as can be seen from the figure, the diameter of the particles is between 0.65 and 1.44 μm, and the material is sufficiently ground.

Fig. 4 is an EDS of the powder mixture of bismuth telluride and boron nitride aerogel prepared in this example after ball milling, wherein B and N atoms account for about 22% of the total number of compound sources.

Fig. 5 is a block of the bismuth telluride and boron nitride aerogel mixed thermoelectric material obtained by hot pressing in this embodiment.

Fig. 6 is a graph of thermal conductivity of the composite thermoelectric material prepared in this example, from which it can be seen that the composite material has a relatively low thermal conductivity.

Fig. 7 shows a thermoelectric unit cell module prepared in this example, in which 29 pairs of unit thermoelectric blocks (29 each of P-type and N-type unit blocks) were used in total.

Fig. 8 is an assembly diagram of the heat collecting platform and the heat pipe manufactured in this embodiment, fig. 9 is a diagram of a solar thermoelectric cell system manufactured in this embodiment 1, and fig. 10 is a power test result of the solar thermoelectric cell system. The result can calculate that the output power of the solar thermoelectric cell can reach 274.36mW, and the light conversion efficiency can reach 34.3%.

Comparative example 1:

this comparative example differs from example 1 in that: the ball milling time in the step one is respectively 6h, 12h, 18h and 24 h. The other steps were the same as in example 1.

The bismuth telluride and boron nitride aerogel mixed material prepared by the comparative example shows that when the ball milling time is 12 hours, the smallest particle diameter can be observed under a Scanning Electron Microscope (SEM), and the clustering phenomenon does not occur in the particle structure.

Comparative example 2:

this comparative example differs from example 1 in that: and in the second step, the pressure of the material hot press is respectively set to be 0.5Mpa, 3Mpa and 6 Mpa. The other steps were the same as in example 1.

The bismuth telluride and boron nitride aerogel mixed material prepared by the comparative example shows that when the pressure of the hot press is 0.5Mpa, the density of the hot-pressed mixed material block is not high, the mixed material block is loose and easy to break, when the pressure of the hot press is 3Mpa, the density of the hot-pressed mixed material block is good, the mixed material block is not easy to break, and the mixed material block is suitable for subsequent grinding and cutting, and when the pressure of the hot press is 6Mpa, the density of the material is good, but the material and a graphite die are easy to adhere to each other and not easy to demold, and the block is easy to crack when the block is taken down.

Comparative example 3:

this comparative example differs from example 1 in that: in the third step, the small copper sheets are arranged in 4 rows, 6 rows and 8 rows respectively, and the other steps are the same as the example 1.

The thermoelectric cell module prepared by the comparative example shows that when the particles are arranged in 4 rows × 5 cases, the generated power of the thermoelectric cell module is too small, the space utilization is insufficient, when the particles are arranged in 6 rows × 5 columns, the generated power of the battery is good, the space utilization is good, and when the particles are arranged in 8 rows × 5 columns, the generated power of the battery is not obviously improved, because the particles are arranged too densely, the heat dissipation of the thermoelectric cell is influenced, the temperature difference between two ends of the battery is too low, and the excessively crowded arrangement is not beneficial to the packaging of the battery.

Comparative example 4:

this comparative example differs from example 1 in that: in the third step, the gaps of the thermoelectric cell crystal blocks are respectively filled with 50% by volume of boron nitride aerogel and 100% by volume of aerogel without filling the boron nitride aerogel, and other steps are the same as those in the embodiment 1.

The thermoelectric cell module prepared by the comparative example found that the generated power of the cell was the smallest when the boron nitride aerogel was not filled in the gap between the thermoelectric cells, that the generated power of the thermoelectric cells was greatly improved when the boron nitride aerogel of 50% volume was filled in the gap between the cells, and that the generated power of the thermoelectric cells was slightly improved when the boron nitride aerogel of 100% volume was filled in the gap between the cells.

Comparative example 5:

this comparative example differs from example 1 in that: in the fourth step, the part of the solar thermoelectric cell system exposed to the air is not treated and is packaged by heat insulation cotton, and other steps are the same as those in the example 1.

The solar thermoelectric cell system prepared by the comparative example shows that when the part exposed to the air is not treated, part of heat is diffused to the air and is not effectively used, and the total power generation power is reduced. And the generated power of the thermoelectric cell module is effectively improved by the system after packaging treatment.