阅读说明：本技术 湿度调节元件及湿度调节单元 (Humidity control element and humidity control unit ) 是由 大神田贵治 平方聪树 市原史基 山田哲也 于 2019-12-06 设计创作，主要内容包括：本发明的湿度调节元件在由离子导电性电解质形成的膜(基部(11))的两面设置有电极(12、13),利用一个电极(12)对水进行电解来进行除湿,并利用另一个电极(13)产生水来进行加湿,电极(12、13)包括：形成于膜的催化剂层(121、131)；及形成于催化剂层(121、131)、且与外部电源(1)电连接的集电体(122、132),集电体(122、132)具有由金属粒子形成的薄膜电极层(123、133)。(The humidity control element of the present invention is provided with electrodes (12, 13) on both surfaces of a membrane (base (11)) formed of an ion-conductive electrolyte, wherein one electrode (12) electrolyzes water to dehumidify the water and the other electrode (13) generates water to humidify the water, and the electrodes (12, 13) include: a catalyst layer (121, 131) formed on the film; and current collectors (122, 132) formed on the catalyst layers (121, 131) and electrically connected to an external power source (1), wherein the current collectors (122, 132) have thin-film electrode layers (123, 133) formed of metal particles.)

1. A humidity control element comprising electrodes provided on both surfaces of a membrane made of an ion-conductive electrolyte, wherein one electrode is used to electrolyze water to dehumidify the water and the other electrode is used to generate water to humidify the water,

the electrode includes:

a catalyst layer formed on the membrane; and

a current collector formed on the catalyst layer and electrically connected to a power source,

the current collector has a thin-film electrode layer formed of metal particles.

2. Humidity conditioning element according to claim 1,

the thin film electrode layer is formed so as to be interposed between the catalyst layer and a flat plate-shaped current collecting member constituting the current collector.

3. Humidity conditioning element according to claim 1,

the thin film electrode layer is formed on the catalyst layer via a flat plate-shaped current collecting member constituting the current collector.

4. Humidity conditioning element according to any of claims 1 to 3,

the metal particles are composed of at least one of titanium, platinum, iridium, ruthenium, platinum iridium, iridium dioxide, and nickel.

5. Humidity conditioning element according to claim 2 or 3,

the current collecting member is made of carbon fiber.

6. A humidity conditioning unit, comprising:

a humidity control element having electrodes on both surfaces of a membrane made of an ion-conductive electrolyte, wherein one electrode is used to electrolyze water to dehumidify the water and the other electrode is used to generate water to humidify the water; and

and a control unit for varying a value of the direct current voltage applied between the two electrodes of the humidity control element so as to set a lower limit value as a theoretical voltage value in electrolysis of water.

7. A humidity conditioning unit as in claim 6,

the control unit varies a value of a direct current voltage applied between the two electrodes of the humidity control element between 1.229V and less than 3V.

8. A humidity conditioning unit as in claim 6 or 7,

includes a humidity detection unit that detects a humidity of an atmosphere dehumidified or humidified by the humidity adjustment element,

the control unit varies a value of the direct-current voltage applied between the two electrodes of the humidity control element based on a detection result obtained by the humidity detection unit.

9. A humidity conditioning unit as in claim 6 or 7,

the electrode includes:

a catalyst layer formed on the membrane; and

a current collector formed on the catalyst layer and electrically connected to a power source,

the humidity adjusting unit includes a voltage detecting unit that detects a voltage value between the catalyst layers,

the control unit varies the dc voltage value between the collectors so that the voltage value detected by the voltage detection unit is within a predetermined range.

Technical Field

The invention relates to a humidity control element and a humidity control unit.

Background

Conventionally, there is known a humidity control element configured by providing an anode on one surface of a membrane made of an ion-conductive electrolyte and providing a cathode on the other surface of the membrane.

In such a humidity conditioning element, an anode-side current collector is formed on one surface of the membrane via an anode-side catalyst layer to constitute an anode, and a cathode-side current collector is formed on the other surface of the membrane via a cathode-side catalyst layer to constitute a cathode.

In the above humidity control element, an external power supply is electrically connected to the anode-side current collector and the cathode-side current collector to apply a direct current voltage, and as a result, a reaction of the following formula (1) is caused in the anode-side catalyst layer and a reaction of the following formula (2) is caused in the cathode-side catalyst layer.

Formula (1) H₂O→2H⁺+1/2O₂+2e^－

Formula (2)2H⁺+2e^－+1/2O₂→H₂O

Thus, the humidity control element can control the humidity by dehumidifying the atmosphere on the anode side and humidifying the atmosphere on the cathode side. The anode-side current collector and the cathode-side current collector forming the anode and the cathode are each formed of a mesh structure made of titanium, nickel, or the like (see, for example, cited document 1).

In addition, conventionally, a dehumidifying unit has been proposed which applies a dc voltage of about 3V between electrodes (between an anode and a cathode) to the humidity control element to perform humidity control and which disconnects the application of the dc voltage (0V) after reaching a target humidity (for example, see patent document 2).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2015-211980

Patent document 2: japanese patent laid-open No. Hei 4-126518

Disclosure of Invention

Technical problem to be solved by the invention

However, in the humidity control element proposed in the above-mentioned cited document 1, very expensive metals such as titanium, nickel, etc. are used as the current collectors of the anode and cathode, and the metals must be processed into a mesh structure, which leads to an increase in manufacturing cost.

Further, in the dehumidification unit proposed in the above cited document 2, the voltage difference is large by changing the value of the direct current voltage applied between the electrodes between a sufficiently high voltage value of 3V and 0V. Therefore, the particles constituting the catalyst layer of the electrode (particularly, the anode) are dissolved and then aggregated again, and as a result, the specific surface area of the particles constituting the catalyst layer is reduced, and as a result, the performance may be lowered at an early stage, and the service life may be shortened.

In view of the above circumstances, an object of the present invention is to provide a humidity control element that can be manufactured at a reduced cost.

In view of the above circumstances, it is an object of the present invention to provide a humidity control unit that can achieve an extension of the service life.

Technical scheme for solving technical problem

In order to achieve the above object, a humidity control element according to the present invention is a humidity control element including electrodes on both surfaces of a membrane made of an ion-conductive electrolyte, one of the electrodes being used to electrolyze water to dehumidify the water and the other electrode being used to generate water to humidify the water, the humidity control element including: a catalyst layer formed on the membrane; and a current collector formed on the catalyst layer and electrically connected to a power supply, the current collector having a thin-film electrode layer formed of metal particles.

In the humidity control element, the thin-film electrode layer is formed so as to be interposed between the catalyst layer and a flat current collector member constituting the current collector.

In the humidity control element, the thin film electrode layer is formed on the catalyst layer through a flat plate-shaped current collecting member constituting the current collector.

In the humidity control element, the metal particles may be made of at least one of titanium, platinum, iridium, ruthenium, platinum iridium, iridium dioxide, and nickel.

In the humidity control element, the current collecting member may be made of carbon fiber.

Further, a humidity control unit according to the present invention includes: a humidity control element having electrodes on both surfaces of a membrane made of an ion-conductive electrolyte, wherein one electrode is used to electrolyze water to dehumidify the water and the other electrode is used to generate water to humidify the water; and a control unit that varies a value of the direct current voltage applied between the two electrodes of the humidity control element so as to set a lower limit value as a theoretical voltage value in electrolysis of water.

In the humidity control unit, the controller may vary a value of a dc voltage applied between the two electrodes of the humidity control element between 1.229V or more and less than 3V.

In the present invention, the humidity control unit includes a humidity detection unit that detects a humidity of an atmosphere dehumidified or humidified by the humidity control element, and the control unit varies a dc voltage value applied between the two electrodes of the humidity control element based on a detection result of the humidity detection unit.

Further, the present invention is characterized in that, in the humidity adjustment unit, the electrode includes: a catalyst layer formed on the membrane; and a current collector formed on the catalyst layer and electrically connected to a power supply, wherein the humidity control unit includes a voltage detection unit that detects a voltage value between the catalyst layers, and the control unit varies the direct current voltage value between the current collectors so that the voltage value detected by the voltage detection unit is within a predetermined range.

Effects of the invention

According to the invention, the electrode comprises: a catalyst layer formed on the membrane; and a current collector formed on the catalyst layer and electrically connected to a power supply, the current collector having a thin-film electrode layer formed of metal particles, and therefore, there is no need to process the current collector into a mesh structure using a very expensive metal such as titanium or nickel as in the prior art, and the following effects are obtained: can be manufactured at low cost, and can realize reduction in manufacturing cost.

Further, according to the present invention, since the humidity control element having the electrodes provided on both surfaces of the membrane made of the ion-conductive electrolyte dehumidifies water by electrolyzing the water with one electrode and humidifies the water by generating the water with the other electrode, and the control unit varies the dc voltage applied between the two electrodes of the humidity control element so that the lower limit value is set as the theoretical voltage value in the electrolysis of the water, the voltage difference applied to the humidity control element can be reduced, the dissolution and aggregation of particles constituting the catalyst layer of the electrodes can be suppressed, and the reduction in the specific surface area can be reduced. This has the effect of extending the service life.

Drawings

Fig. 1 is a schematic view showing a structure of a humidity adjustment member of an embodiment of the present invention in cross section.

Fig. 2 is a cross-sectional view showing the structure of the thin film electrode layer shown in fig. 1.

Fig. 3 is a schematic diagram showing a configuration of a modification of the humidity control element according to the embodiment of the present invention in cross section.

Fig. 4 is a schematic view schematically showing the structure of a humidity adjusting unit according to an embodiment of the present invention.

Fig. 5 is a schematic view showing an example of arrangement of a humidity adjustment element constituting the humidity adjustment unit shown in fig. 4.

Fig. 6 is a flowchart showing the processing content of the humidity adjustment control process performed by the control unit shown in fig. 4.

Fig. 7 is a schematic diagram schematically showing the configuration of a modification of the humidity control unit according to the embodiment of the present invention.

Detailed Description

Hereinafter, preferred embodiments of the humidity control element and the humidity control unit according to the present invention will be described in detail with reference to the accompanying drawings.

< element for adjusting humidity >

Fig. 1 is a schematic view showing a structure of a humidity adjustment member of an embodiment of the present invention in cross section. The humidity adjustment element 10 illustrated here by way of example is configured to include a base 11, a dehumidifying electrode 12, and a humidifying electrode 13.

The base 11 is made of a film formed of an ion conductive electrolyte such as a fluororesin electrolyte film, and has a property of allowing hydrogen ions to pass therethrough. The thickness of the base 11 is set to 200 μm, for example.

The dehumidifying electrode 12 is formed on one surface of the base 11, that is, one surface 11a of a membrane made of an ion-conductive electrolyte, and includes a dehumidifying catalyst layer 121 and a dehumidifying current collector 122.

The dehumidifying catalyst layer 121 is formed on the one surface 11a of the base 11, and is configured to disperse platinum catalyst particles having a particle diameter of, for example, 10nm, such as platinum black, in the solid polymer electrolyte resin.

The dehumidifying collector 122 includes a dehumidifying collector member 122a and a dehumidifying collector frame 122 b. The dehumidifying current collecting member 122a is made of carbon fiber such as carbon paper, and is formed in a flat plate shape. As shown in fig. 2, a thin-film electrode layer 123 made of metal particles is formed on one surface of the dehumidifying current-collecting member 122 a.

The thin film electrode layer 123 is formed on one surface of the current collector for dehumidification 122a by coating or the like, and is made of metal particles made of at least one of titanium, platinum, iridium, ruthenium, platinum iridium, iridium dioxide, and nickel. Since the thin-film electrode layer 123 is formed by coating, various patterns can be formed, and in the present embodiment, a plurality of rectangular openings 123a are formed. The thickness of the thin-film electrode layer 123 is set to about 10 to 50 μm, for example.

The current collector for dehumidification 122a is bonded to the dehumidification catalyst layer 121 by, for example, hot pressing so that the thin film electrode layer 123 is in contact with the dehumidification catalyst layer 121, and is integrated with the dehumidification catalyst layer 121.

The dehumidification collector frame 122b is made of a conductive material and is formed in a frame shape. The dehumidification collector frame 122b is joined to the dehumidification collector member 122 a.

The humidifying electrode 13 is formed on the other surface of the base 11, that is, the other surface 11b of the membrane formed of the ion-conductive electrolyte, and is configured to include a humidifying catalyst layer 131 and a humidifying current collector 132.

The humidification catalyst layer 131 is formed on the other surface 11b of the base 11, and is configured by dispersing carbon particles and platinum nanoparticles in a solid polymer electrolyte resin.

The humidification current collector 132 includes a humidification current collector member 132a and a humidification current collector frame 132 b. The humidification current collector 132a is made of carbon fiber such as carbon paper, and is formed in a flat plate shape. A thin film electrode layer 133 made of metal particles is formed on one surface of the humidification current collector 132 a.

The thin-film electrode layer 133 is formed on one surface of the humidification current collector 132a by coating, and is made of metal particles made of at least one of titanium, platinum, iridium, ruthenium, platinum iridium, iridium dioxide, and nickel. Since the thin-film electrode layer 133 is formed by coating, various patterns can be formed, and in the present embodiment, a plurality of rectangular openings 133a are formed, as in the thin-film electrode layer 123 constituting the current collector for dehumidification 122. The thickness of the thin-film electrode layer 133 is set to about 10 to 50 μm, for example.

The humidification current collector 132a is bonded to the humidification catalyst layer 131 such that the thin-film electrode layer 133 is in contact with the humidification catalyst layer 131, for example, by hot pressing, and is integrated with the humidification catalyst layer 131.

The humidification current collecting frame 132b is made of a conductive material and formed in a frame shape. The humidification collector frame 132b is joined to the humidification collector member 132 a.

In the humidity control element 10, the dehumidification collector frame 122b constituting the dehumidification electrode 12 and the humidification collector frame 132b constituting the humidification electrode 13 are electrically connected to the external power supply 1 through the lead wires 2, respectively. That is, the dehumidifying electrode 12 constitutes an anode by electrically connecting the dehumidifying collector frame 122b (dehumidifying collector 122) of the dehumidifying electrode 12 to the positive electrode of the external power supply 1, and the humidifying electrode 13 constitutes a cathode by electrically connecting the humidifying collector frame 132b (humidifying collector 132) of the humidifying electrode 13 to the negative electrode of the external power supply 1.

In the humidity control element 10 having the above-described structure, when a current is supplied from the external power supply 1 and is energized, a reaction of the following formula (3) occurs in the dehumidifying electrode 12, and a reaction of the following formula (4) occurs in the humidifying electrode 13.

That is, the atmosphere around the dehumidifying electrode 12 is dehumidified by reducing water molecules (water components). Also, the hydrogen ions generated in the dehumidifying electrode 12 react with oxygen molecules (oxygen components) in the ambient atmosphere of the humidifying electrode 13 through the base portion 11 to form water molecules, thereby humidifying the ambient atmosphere of the humidifying electrode 13.

Formula (3) H₂O→2H⁺+1/2O₂+2e^－

Formula (4)2H⁺+2e^－+1/2O₂→H₂O

In the humidity conditioning element 10 having the above structure, the dehumidifying current collector 122 and the humidifying current collector 132 constituting the dehumidifying electrode 12 and the humidifying electrode 13 are constituted by forming the thin film electrode layers 123, 133 composed of metal particles on one surface of each of the dehumidifying current collector member 122a and the humidifying current collector member 132a, and therefore the current collection resistance in the surface direction of the humidity conditioning element 10 can be reduced. Further, since it is not necessary to form a mesh structure using a very expensive metal such as titanium or nickel as in the conventional art, the mesh structure can be manufactured at low cost and the manufacturing cost can be reduced.

According to the humidity control element 10, since the planar humidification current collector 132a is provided in the humidification current collector 132, water molecules generated in the humidification catalyst layer 131 pass through the humidification current collector 132a and are dispersed in various directions, and the atmosphere around the humidification electrode 13 can be humidified satisfactorily.

The preferred embodiment of the humidity control element 10 according to the present invention has been described above, but the present invention can be variously modified.

The thin film electrode layers 123 and 133 constituting the humidity control element 10 are formed so as to be interposed between the catalyst layers (the dehumidification catalyst layer 121 and the humidification catalyst layer 131) and the current collecting members (the dehumidification current collecting member 122a and the humidification current collecting member 132a), but in the present invention, as shown in fig. 3, the thin film electrode layers 124 and 134 may be formed on the catalyst layers (the dehumidification catalyst layer 121 and the humidification catalyst layer 131) via the current collecting members (the dehumidification current collecting member 122a and the humidification current collecting member 132 a).

In the above embodiment, the thin film electrode layers 123, 133 are formed on one surface of the current collecting member (the dehumidification current collecting member 122a and the humidification current collecting member 132a) and then bonded to the catalyst layers (the dehumidification catalyst layer 121 and the humidification catalyst layer 131), but in the present invention, the thin film electrode layers may be formed on the catalyst layers by direct coating to constitute the current collectors. That is, the current collecting member may not be provided.

< humidity adjusting unit >

Fig. 4 is a schematic view schematically showing the structure of a humidity adjusting unit according to an embodiment of the present invention. The humidity control unit 20 illustrated here includes a humidity control element 10, a humidity detection sensor (humidity detection unit) 21, and a control unit 22.

Since the humidity adjustment element 10 has the same structure as that shown in fig. 1, the same reference numerals are attached and a repeated explanation thereof is omitted. As shown in fig. 5, the humidity control element 10 is disposed so as to close the ventilation hole 4 formed in the wall portion of the casing 3, such that the dehumidifying electrode 12 constituting the anode faces the outside of the casing 3 and the humidifying electrode 13 constituting the cathode faces the inside of the casing 3.

The humidity detection sensor 21 is provided inside the casing 3, and detects the humidity inside the casing 3 humidified by the humidity adjustment element 10. The humidity detection sensor 21 outputs the detected humidity to the control unit 22 as a humidity signal.

The control unit 22 controls the operation of the humidity control unit 20 in accordance with the program and data stored in the memory 23. The controller 22 drives the external power source 1 so that the dc voltage applied between the two electrodes 12 and 13 of the humidity control element 10 varies between 1.229V or more and less than 3V, and more preferably between 1.229V or more and 2.8V or less.

Here, 1.229V, which is the lower limit of the dc voltage value, is the theoretical voltage value in the electrolysis of water. The upper limit of the dc voltage value, 2.8V, is a voltage value at which the humidity control reaction (the dehumidification reaction and the humidification reaction) occurs well in the humidity control element 10.

The control Unit 22 may be realized by software that is a program executed by a Processing device such as a CPU (Central Processing Unit), may be realized by hardware such as an IC (Integrated Circuit), or may be realized by both software and hardware.

The storage unit 23 stores target range information of the humidity inside the casing 3, more specifically, information about a target lower limit value and a target upper limit value.

In the humidity control unit 20, the control unit 22 drives the external power supply 1 to apply a dc voltage between the two electrodes 12 and 13 of the humidity control element 10, thereby generating the reaction of the formula (3) in the dehumidifying electrode 12 and the reaction of the formula (4) in the humidifying electrode 13, thereby humidifying the internal atmosphere of the housing 3.

Fig. 6 is a flowchart showing the processing content of the humidity adjustment control process performed by the control unit 22 shown in fig. 4.

In the humidity adjustment process, the control unit 22 determines whether or not a humidity signal is input from the humidity detection sensor 21 (step S101). When the humidity signal is not input from the humidity detection sensor 21 (no in step S101), the control unit 22 repeats the process of step S101.

On the other hand, when a humidity signal is input (step S101: YES), the control unit 22 reads the target range information from the storage unit 23, and determines whether or not the detected humidity included in the humidity signal is equal to or greater than the target lower limit value (step S102).

When the detected humidity is not equal to or higher than the target lower limit value (no in step S102), that is, when the detected humidity is lower than the target lower limit value, the control unit 22 sets the dc voltage value (hereinafter, also referred to as an applied voltage value) applied to the humidity control element 10 from the external power supply 1 to the upper limit value (2.8V) (step S103), and then returns the process to end the current processing.

This promotes the dehumidification reaction and humidification reaction of the humidity control element 10, and the humidity in the internal atmosphere of the casing 3 is shifted in the upward direction.

When the detected humidity is equal to or higher than the target lower limit value (yes in step S102), the control unit 22 determines whether the detected humidity is equal to or lower than the target upper limit value (step S104).

When the detected humidity is not equal to or less than the target upper limit value (no in step S104), that is, when the detected humidity exceeds the target upper limit value, the control unit 22 sets the applied voltage value to the lower limit value (1.229V) (step S105), and returns the process to end the current processing.

As a result, the dehumidification reaction and the humidification reaction of the humidity control element 10 do not proceed, and the humidity in the internal atmosphere of the casing 3 is shifted in the downward direction. Here, the lower limit of the applied voltage value is a theoretical voltage value (1.229V) in the electrolysis of water, and therefore the humidity control reaction theoretically occurs in the humidity control element 10, but actually does not occur due to the resistance of the components of the humidity control element 10 and the like. That is, it can be said that the theoretical voltage value is close to the maximum value of the voltage value at which the humidity adjustment reaction does not proceed.

When the detected humidity is not equal to or less than the target lower limit value (yes in step S104), that is, when the detected humidity is within the target range, the control unit 22 maintains the applied voltage value (step S106), and then returns the process to end the current process.

As described above, in the humidity control unit 20 according to the embodiment of the present invention, the controller 22 varies the dc voltage value applied between the two electrodes 12 and 13 of the humidity control element 10 between 1.229V or more and less than 3V, so that the voltage difference applied to the humidity control element 10 can be reduced. Therefore, the dissolution and aggregation of the particles of the catalyst layers (the dehumidifying catalyst layer 121 and the humidifying catalyst layer 131) can be suppressed in the two electrodes 12, 13, and the reduction of the specific surface area can be reduced. Thus, according to the humidity control unit 20, the service life can be extended.

The preferred embodiment of the humidity control unit 20 according to the present invention has been described above, but the present invention can be variously modified.

In the above embodiment, the humidity control element 10 is disposed such that the dehumidifying electrode 12 faces the outside of the casing 3 and the humidifying electrode 13 faces the inside of the casing 3, but in the present invention, the humidity control element may be disposed such that the humidifying electrode faces the outside of the casing and the dehumidifying electrode faces the inside of the casing.

In the above embodiment, the controller 22 applies the dc voltage between the two electrodes 12 and 13 of the humidity control element 10 at a value of 1.229V or more and 2.8V or less, but in the present invention, when the lower limit value of the applied voltage is 1.229V, the upper limit value of the applied voltage may be the same as that of the conventional one.

In the above embodiment, the structure of the humidity control element 10 is shown as an example in fig. 1, but in the present invention, the humidity control element may have a known structure.

In the above embodiment, the control unit 22 varies the dc voltage value applied between the two electrodes 12 and 13 of the humidity control element 10 based on the detection result obtained by the humidity detection sensor 21, but in the present invention, when a table indicating the correlation among the temperature, the current value, and the relative humidity is stored in the storage unit, the humidity may be predicted based on the current value passing through the humidity control element, and the dc voltage value may be varied.

In the above embodiment, the control unit 22 varies between the upper limit value of the applied voltage value and the lower limit value of the applied voltage value in the humidity adjustment control process, but in the present invention, the applied voltage value may be varied so as to gradually increase or gradually decrease.

The humidity control unit according to the present invention may have the following configuration. Fig. 7 is a schematic diagram schematically showing the configuration of a modification of the humidity control unit according to the embodiment of the present invention. The same components as those of the humidity control unit 20 are denoted by the same reference numerals, and redundant description thereof is omitted.

The humidity control unit 30 illustrated here includes the humidity control element 10, a voltage detection unit 31, and a control unit 32.

The voltage detection unit 31 detects a voltage value between the dehumidification catalyst layer 121 and the humidification catalyst layer 131. In more detail, the voltage detecting section 31 detects a voltage value between the two catalyst layers 121, 131 using probes 31a, 31b electrically connected to the dehumidifying catalyst layer 121 and the humidifying catalyst layer 131, respectively. Here, although not explicitly shown in the drawing, the probes 31a, 31b are electrically contacted with the dehumidifying catalyst layer 121 and the humidifying catalyst layer 131 by applying gold plating to a rectangular parallelepiped block made of copper. The shape and structure of the probes 31a and 31b are not particularly limited as long as they can be electrically connected to the dehumidification catalyst layer 121 and the humidification catalyst layer 131, respectively, and the shape may be a flat plate, a convex lens, a needle, a sword, a wire, or the like.

The control unit 32 controls the operation of the humidity control unit 30 in accordance with the program and data stored in the memory 33. The controller 32 drives the external power source 1 so that the dc voltage applied between the two electrodes 12 and 13 of the humidity control element 10 varies between 1.229V or more and less than 3V, and more preferably between 1.229V or more and 2.8V or less.

The control Unit 32 may be realized by software that is a program executed by a Processing device such as a CPU (Central Processing Unit), may be realized by hardware such as an IC (Integrated Circuit), or may be realized by both software and hardware.

In this humidity control unit 30, the control unit 32 drives the external power supply 1 to apply a dc voltage between the two electrodes 12 and 13 of the humidity control element 10, thereby causing the reaction of the above formula (3) to occur in the dehumidifying electrode 12 and causing the reaction of the above formula (4) to occur in the humidifying electrode 13, thereby humidifying the internal atmosphere of the housing 3.

Further, when the voltage value detected by the voltage detecting portion 31 (hereinafter also referred to as a detection voltage value) deviates from the applied voltage value of the external power supply 1, the control portion 32 performs correction of variation in the voltage applied to the humidity adjustment element 10 by the external power supply 1 so that the detection voltage value approximates the applied voltage value, that is, so that the detection voltage value is within a predetermined range.

This can suppress the reduction in the reaction in the catalyst layers (the dehumidification catalyst layer 121 and the humidification catalyst layer 131) due to the IR loss caused by the contact resistance between the components in the electrodes (the dehumidification electrode 12 and the humidification electrode 13) of the humidity control element 10, and can favorably perform the humidity control reaction in the humidity control element 10.

Description of the reference symbols

1 … external power supply, 10 … humidity adjusting element, 11 … base, 12 … dehumidifying electrode, 121 … dehumidifying catalyst layer, 122 … dehumidifying collector, 122a … dehumidifying collector member, 122b … dehumidifying collector frame, 123 … thin film electrode layer, 13 … humidifying electrode, 131 … humidifying catalyst layer, 132 … humidifying collector, 132a … humidifying collector member, 132b … humidifying collector frame, 133 … thin film electrode layer, 20 … humidity adjusting unit, 21 … humidity detecting sensor, 22 … control part and 23 … storage part.