JP2014112464A - Fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of controlling humidity according to an operation state of a fuel cell without decreasing performance of the fuel cell.SOLUTION: A fuel cell 10 comprises a membrane electrode assembly 20 and a humidity control unit 30. The humidity control unit 30 is in contact with an anode catalyst layer 24, and comprises an anode chamber 32 which supplies hydrogen to the anode catalyst layer 24, vapor liquid separation means 38 through which only a gas can pass, and a humidity conditioning chamber 34 which is isolated from the anode catalyst layer 24 by the vapor liquid separation means 38 and stores an aqueous solution 36 for humidity control containing a prescribed inorganic salt exceeding a saturated amount. Humidity of the anode chamber 32 is controlled via the vapor liquid separation means 38 by absorbing water vapor existing in the anode chamber 32 into the aqueous solution 36 for humidity control and supplying the water vapor evaporated from the aqueous solution 36 for humidity control to the anode chamber 32.

Description

  The present invention relates to a fuel cell. More specifically, the present invention relates to a fuel cell in which cells are arranged in a plane.

  A fuel cell is a device that generates electrical energy from hydrogen and oxygen, and can achieve high power generation efficiency. The main features of the fuel cell are direct power generation that does not go through the process of thermal energy and kinetic energy as in the conventional power generation method, so that high power generation efficiency can be expected even on a small scale, and there is little emission of nitrogen compounds, Noise and vibration are also small, so the environmental performance is good. In this way, the fuel cell can effectively use the chemical energy of fuel and has environmentally friendly characteristics, so it is expected as an energy supply system for the 21st century, from space use to automobiles and portable devices. It is attracting attention as a promising new power generation system that can be used for various applications from large-scale power generation to small-scale power generation, and technological development is in full swing toward practical application.

  Among them, solid polymer fuel cells are characterized by low operating temperature and high output density compared to other types of fuel cells. Especially, in recent years, mobile devices (cell phones, notebook personal computers, PDAs, It is expected to be used for power sources such as MP3 players, digital cameras, electronic dictionaries, and electronic books. As one form of a polymer electrolyte fuel cell for portable devices, a planar array type fuel cell in which a plurality of single cells are arranged in a planar shape is known.

JP 2009-81111 A

  In a polymer electrolyte fuel cell, if the humidity around the anode is low at start-up, the electrolyte membrane does not function sufficiently. On the other hand, high humidity during operation can cause flooding. Therefore, it is necessary to maintain the humidity around the anode in an appropriate range during stoppage and operation. As a technique for adjusting the humidity, there is known a fuel cell in which a humidity control layer made of a water-absorbing material in the form of water-absorbing inorganic particles is disposed in contact with a current collector (Patent Document 1).

  However, the technique of Patent Document 1 has a problem that humidity adjustment by the humidity control layer is insufficient. In particular, this technique has a problem that the humidity cannot be adjusted according to the operating state of the fuel cell. Moreover, since there is a possibility that the water-absorbing inorganic substance comes into contact with the anode, there is a problem that the performance of the fuel cell is lowered.

  This invention is made | formed in view of such a subject, The objective is to provide the technique which can adjust humidity according to the operating state of a fuel cell, without reducing the performance of a fuel cell.

  One embodiment of the present invention is a fuel cell. The fuel cell includes a membrane electrode assembly including an electrolyte membrane, an anode catalyst layer provided on one surface of the electrolyte membrane, and a cathode catalyst layer provided on the other surface of the electrolyte membrane, and an anode And a humidity control unit in contact with the catalyst layer. The humidity control unit includes an anode chamber for supplying hydrogen to the anode catalyst layer, a gas-liquid separation unit capable of passing only gas, and a predetermined inorganic substance that is isolated from the anode catalyst layer by the gas-liquid separation unit and exceeds the saturation amount A humidity control chamber containing a humidity control aqueous solution containing salt. The water vapor present in the anode chamber is absorbed by the humidity control aqueous solution, and the water vapor evaporated from the humidity control aqueous solution is supplied to the anode chamber, whereby the humidity of the anode chamber is adjusted via the gas-liquid separation means.

  According to this aspect, the humidity of the anode chamber is adjusted by the humidity control aqueous solution during operation and stop of the fuel cell. Further, since the humidity control aqueous solution is isolated from the anode catalyst layer by the gas-liquid separation means, the performance of the fuel cell is not deteriorated. Moreover, since the water produced on the cathode catalyst layer side can be controlled indirectly by adjusting the humidity of the anode chamber, flooding of the cathode catalyst layer can be prevented. In addition, since the anode catalyst layer and the cathode catalyst layer can be maintained at a humidity within a desired range while the fuel cell is stopped, the fuel cell can be started quickly.

  The fuel cell of the above-described aspect may further include a heating means for evaporating water from the humidity control aqueous solution to the outside of the humidity control chamber by heating. Further, the heating means may be a hydrogen supply unit provided adjacent to the humidity control chamber and having a hydrogen storage alloy for supplying hydrogen to the humidity control unit. Moreover, the humidity control chamber may be removable. In addition, the humidity control chamber may be shielded during operation of the fuel cell, and may be further provided with a shielding unit that does not shield the humidity control chamber during the stop. The humidity control chamber further includes a shielding means for shielding the humidity control chamber. The humidity control chamber is separated into a plurality of compartments facing the anode chamber. A plurality of humidity control aqueous solutions having different saturated water vapor pressures are accommodated, respectively, and the shielding means may shield at least some of the plurality of compartments according to the operating state of the fuel cell.

  A combination of the above-described elements as appropriate can also be included in the scope of the invention for which patent protection is sought by this patent application.

  According to the present invention, the humidity inside the fuel cell can be adjusted according to the operating state without degrading the performance of the fuel cell.

1 is a schematic side view showing the structure of a fuel cell according to Embodiment 1. FIG. 3 is a graph showing relative humidity at each temperature of an inorganic salt that can be used in the fuel cell according to Embodiment 1. FIG. 5 is a schematic side view showing the structure of a fuel cell according to Embodiment 2. FIG. 6 is a schematic side view showing the structure of a fuel cell according to Embodiment 3. FIG. 4A is a schematic view of the fuel cell in operation. FIG. 4B is a schematic view of a state in which the humidity control unit of the fuel cell is removed during operation stop. 6 is a schematic side view showing the structure of a fuel cell according to Embodiment 4. FIG. FIG. 5 (a) is a schematic view of the fuel cell in operation. FIG. 5B is a schematic view showing a state in which the humidity control unit of the fuel cell is removed while the operation is stopped. FIG. 6 is a schematic side view showing the structure of a fuel cell according to Embodiment 5. FIG. 6A is a schematic view of the fuel cell during operation stop. FIG. 6B is a schematic diagram of the fuel cell in operation. 10 is a schematic side view showing the structure of a fuel cell according to Embodiment 6. FIG. FIG. 7A is a schematic view of the fuel cell during operation stop. FIG. 7B is a schematic diagram of the fuel cell in operation. FIG. 7C is a schematic view of the fuel cell during the performance recovery of the humidity control aqueous solution. FIG. 10 is a schematic side view illustrating the structure of a fuel cell and a cathode humidity control apparatus according to a seventh embodiment. FIG. 8A is a schematic view of a humidity control device for a cathode for adjusting the humidity of an operating fuel cell and a cathode catalyst layer. FIG. 8B is a schematic side view showing a state in which the cathode humidity control device is attached to the fuel cell while the operation is stopped.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

(Embodiment 1)
FIG. 1 is a schematic side view showing the structure of a fuel cell 10 according to Embodiment 1. FIG. Each schematic diagram is a diagram schematically showing mainly the functions and connections of each component, and does not limit the positional relationship or arrangement of each component.

  As shown in FIG. 1, the fuel cell 10 includes a membrane electrode assembly 20, a humidity adjustment unit 30, and a hydrogen supply unit 50 as main components.

  The membrane electrode assembly 20 includes an electrolyte membrane 22, an anode catalyst layer 24 provided on one surface of the electrolyte membrane 22, and a cathode catalyst layer 26 provided on the other surface of the electrolyte membrane 22. Hydrogen is supplied to the anode catalyst layer 24 as a fuel gas. On the other hand, air is supplied to the cathode catalyst layer 26 as an oxidant. A cell is configured by sandwiching the electrolyte membrane 22 between the pair of anode catalyst layer 24 and cathode catalyst layer 26, and each cell generates power by an electrochemical reaction between hydrogen and oxygen in the air.

  Thus, in the fuel cell of the present embodiment, the cathode catalyst layer 26 is paired with the anode catalyst layer 24, and the cells are formed in a planar shape. Although only one cell is shown here, a plurality of cells may be formed in a stacked structure.

  A gas-liquid separation means 28 is provided on the surface of the cathode catalyst layer 26 opposite to the surface on which the electrolyte membrane 22 is provided, with a predetermined distance from the surface. The gas-liquid separation means 28 allows water vapor to pass but not liquid water. As the gas-liquid separation means 28, a gas-liquid separation membrane such as a Teflon (registered trademark) porous membrane can be used.

  The humidity adjusting unit 30 is formed in a container shape with one surface of the surface of the anode catalyst layer 24 opposite to the surface on which the electrolyte membrane 22 is provided. The humidity adjusting unit 30 includes an anode chamber 32 and a humidity control chamber 34 in order from the opposite surface. Hydrogen supplied to the anode catalyst layer 24 is placed in the anode chamber 32 by a hydrogen supply unit 50 described later. The humidity control chamber 34 contains a humidity control aqueous solution 36 containing a predetermined inorganic salt exceeding the saturation amount. The anode chamber 32 and the humidity control chamber 34 are separated from each other by a gas-liquid separation means 38. The gas-liquid separation means 38 allows water vapor to pass but not liquid water. As the gas-liquid separation means 38, a gas-liquid separation film similar to the gas-liquid separation means 28 can be used.

  When the humidity control aqueous solution 36 is accommodated in the humidity control chamber 34, the humidity of the anode chamber 32 is maintained at the specific humidity of the inorganic salt when the water vapor pressure inside the humidity control aqueous solution 36 and the anode chamber 32 reaches an equilibrium state. Be drunk. In order to easily adjust the humidity of the anode chamber 32, it is preferable to reduce the volume of the anode chamber 32 and increase the surface area of the gas-liquid separation means 38. When the volume of the anode chamber 32 is relatively large with respect to the surface area of the gas-liquid separation means 38, a fan is attached to the inside of the humidity adjusting unit 30 to agitate the air inside the anode chamber 32 and balance the humidity. It is preferable to easily reach the state.

  When the anode chamber 32 is kept at a low humidity, the back diffusion of water generated in the cathode catalyst layer 26 is promoted toward the anode catalyst layer 24 side. Thereby, flooding of the cathode catalyst layer 26 can be prevented. On the other hand, when the anode chamber 32 is kept at high humidity, the water generated in the cathode catalyst layer 26 is less likely to reversely diffuse toward the anode catalyst layer 24 side. Thereby, drying (dry-out) of the cathode catalyst layer 26 is prevented. That is, by properly using inorganic salts according to the performance of the fuel cell 10 and the external environment, the humidity around the anode catalyst layer 24 and the cathode catalyst layer 26 can be adjusted, and the performance of the fuel cell 10 can be stabilized. it can.

Examples of the inorganic salt used for the humidity control aqueous solution 36 include, for example, cesium fluoride (CsF), lithium bromide (LiBr), lithium chloride (LiCl), and acetic acid in order from the lowest relative humidity to be controlled. Potassium (CH ₃ COOK), magnesium chloride (MgCl ₂ ), potassium carbonate (K ₂ CO ₃ ), sodium bromide (NaBr), potassium iodide (KI), sodium chloride (NaCl), potassium chloride (KCl), sulfuric acid Potassium (K ₂ SO ₄ ) or the like can be used.

  FIG. 2 is a graph showing the relative humidity at each temperature of the inorganic salt that can be used in the fuel cell 10 according to the first embodiment. Relative humidity at 9 stages of temperature is shown at 5 ° C intervals from 5 ° C to 45 ° C. In any of the above-mentioned compounds, the relative humidity tends to slightly decrease as the temperature increases, but the relative humidity hardly depends on the temperature.

The selection of the inorganic salt is performed according to the final humidity of the anode chamber 32. For example, when the humidity of the anode chamber 32 is desired to be low, an inorganic salt shown at the bottom of the graph shown in FIG. 2, that is, an inorganic salt close to cesium fluoride (CsF) is selected. In order to adjust the humidity to high humidity, an inorganic salt shown at the top of the graph shown in FIG. 2, that is, an inorganic salt close to potassium sulfate (K ₂ SO ₄ ) is selected.

  The hydrogen supply unit 50 supplies hydrogen to the anode chamber 32 through the gas pipe 52 in a state where the valve 54 is opened. The water generated by the electrochemical reaction in the cathode catalyst layer 26 and reaching the anode chamber 32 by back diffusion is absorbed by the humidity control aqueous solution 36, and the anode chamber 32 is kept at a constant humidity. When all of the inorganic salts in the humidity control aqueous solution 36 are dissolved and become a saturated aqueous solution, and the humidity control capability is lost, the water is discharged from the anode chamber 32 through the gas pipe 60 with the valve 62 opened after the operation is stopped. The Since the valve 62 is closed in the operating state, the humidity adjusting unit 30 forms a dead end space that is closed with respect to other than the hydrogen supply unit 50.

  During operation of the fuel cell 10, hydrogen supplied from the hydrogen supply unit 50 reacts at the membrane electrode assembly 20. Water generated by this reaction reaches the anode chamber 32 by back diffusion. A part of the reached water passes through the gas-liquid separation means 38 in the state of water vapor and is absorbed by the humidity control aqueous solution 36. On the other hand, when the humidity of the anode chamber 32 is low, such as when the fuel cell 10 is stopped, the water vapor evaporated from the humidity control aqueous solution 36 passes through the gas-liquid separation means 38 and is supplied to the anode chamber 32.

  According to the present embodiment, the humidity of the anode chamber 32 is adjusted by the humidity adjusting aqueous solution 36 during operation and stop of the fuel cell 10. Further, since the humidity adjustment aqueous solution 36 is isolated from the anode catalyst layer 24 by the gas-liquid separation means 38, the performance of the fuel cell 10 is not deteriorated. Further, by controlling the humidity of the anode chamber 32, it is possible to indirectly control the water generated on the cathode catalyst layer 26 side, so that flooding of the cathode catalyst layer 26 can be prevented. In addition, since the anode catalyst layer 24 and the cathode catalyst layer 26 can be maintained at a desired range of humidity while the operation of the fuel cell 10 is stopped, the fuel cell 10 can be started quickly.

(Embodiment 2)
FIG. 3 is a schematic side view showing the structure of the fuel cell 10 according to the second embodiment. Hereinafter, the fuel cell 10 according to Embodiment 2 will be described focusing on differences from Embodiment 1.

  In the fuel cell 10 of Embodiment 2, the hydrogen supply unit 50 is provided adjacent to the humidity control chamber 34. The hydrogen supply unit 50 includes a hydrogen storage alloy for supplying hydrogen to the humidity control unit 30. When the valve 58 attached to the gas pipe 56 is opened and the hydrogen supply unit 50 is filled with hydrogen through the gas pipe 56, the hydrogen supply unit 50 generates heat. By supplying this heat to the humidity control chamber 34, the water absorbed in the humidity control aqueous solution 36 is evaporated to the outside of the humidity control chamber 34 via the gas-liquid separation means 38, and the inorganic salt is recrystallized. The humidity control performance of the humidity control aqueous solution 36 can be recovered. That is, the hydrogen supply unit 50 has a function of supplying hydrogen to the anode chamber 32 and also functions as a heating unit that supplies heat to the humidity control chamber 34. Since the gas pipe 56 is not used simultaneously with the gas pipe 52, the hydrogen supply unit 50 may be filled with the hydrogen gas by using the gas pipe 52 in common with the gas pipe 52.

  According to the present embodiment, the humidity control performance of the humidity control aqueous solution 36 can be recovered in a space-saving and simple and low cost manner.

(Embodiment 3)
FIG. 4 is a schematic side view illustrating the structure of the fuel cell 10 according to the third embodiment. FIG. 4A is a schematic diagram of the fuel cell 10 in operation. FIG. 4B is a schematic view showing a state in which the humidity control unit 70 of the fuel cell 10 is removed while the operation is stopped. In the fuel cell 10 of the present embodiment, in addition to the gas-liquid separation means 38, an additional gas-liquid separation means 40 is provided in the anode chamber 32, and the hydrogen supply unit 50, humidity control chamber 34, and gas-liquid separation The difference from the fuel cell 10 according to the second embodiment is that the humidity control unit 70 constituted by the means 38 can be removed from other portions of the fuel cell 10. In addition to the valve 54 for adjusting the open / close state of the anode chamber 32, the gas pipe 52 is provided with a valve 64 for adjusting the hydrogen supply unit 50 to a closed state when the humidity control unit 70 is removed.

  A heating device 100 which is a device different from the fuel cell 10 is applied to the humidity control unit 70 separated from the fuel cell 10 from the gas-liquid separation means 38 side. The heating device 100 heats the humidity control aqueous solution 36 via the gas-liquid separation means 38, thereby allowing the water absorbed by the humidity control aqueous solution 36 to flow outside the humidity control chamber 34 via the gas-liquid separation means 38. Evaporate.

  By providing the additional gas-liquid separation means 40 in the anode chamber 32, the anode chamber 32 is covered with the gas-liquid separation means 40 even when the humidity control unit 70 having the gas-liquid separation means 38 is removed. .

  According to the present embodiment, the humidity control performance of the humidity control aqueous solution 36 can be recovered more efficiently. Further, since the anode chamber 32 is covered with the gas-liquid separation means 40, even when the humidity control unit 70 is removed, water is prevented from excessively evaporating from the anode chamber 32, and the humidity of the anode chamber 32 is appropriately Can be kept in. In addition, it is possible to prevent the performance of the fuel cell 10 from being deteriorated due to foreign matters mixed in the anode chamber 32. In addition to the heating device 100, heat may be applied to the humidity control aqueous solution 36 using the hydrogen supply unit 50 as in the second embodiment. Alternatively, the humidity control aqueous solution 36 may be directly exchanged by opening the humidity control chamber 34 with the humidity control unit 70 removed. The humidity control unit 70 includes the humidity control chamber 34 and the gas-liquid separation unit 38, and the hydrogen supply unit 50 may not be provided.

(Embodiment 4)
FIG. 5 is a schematic side view illustrating the structure of the fuel cell 10 according to the fourth embodiment. FIG. 5A is a schematic view of the fuel cell 10 in operation. FIG. 5B is a schematic view of the fuel cell 10 with the humidity control unit 70 removed while the operation is stopped. The fuel cell 10 of the present embodiment differs from the fuel cell 10 according to Embodiment 3 in that a shielding means 80 is provided instead of the gas-liquid separation means 40.

  The shielding unit 80 includes a storage chamber 82, a shielding member 84, a first roller 86, and a second roller 88. The accommodating chamber 82 accommodates the shielding member 84, the first roller 86, and the second roller 88. The shielding member 84 does not have air permeability and shields water vapor from coming out of the anode chamber 32 in a state where the shielding member 84 is pulled out from the storage chamber 82. The first roller 86 is wound around the shielding member 84 and accommodated in the accommodation chamber 82. The second roller 88 is in a state where the shielding member 84 is stretched so as to prevent an excessive load from being applied to the shielding member 84 when the shielding member 84 is pulled out from the storage chamber 82 and not to contact the anode catalyst layer 24. Keep on.

  As shown in FIG. 5B, the shielding member 84 is accommodated in a state where the humidity control unit 70 is removed from the fuel cell 10 at a coupling portion (not shown) of the gas pipe 52 provided between the valve 54 and the valve 64. The anode chamber 32 is covered by pulling out from the chamber 82 and fixing the shielding member 84 on the side surface of the anode chamber 32 opposite to the shielding means 80.

  According to the present embodiment, since only one gas-liquid separation means is used in the humidity adjusting unit 30, the humidity can be adjusted more quickly than in the third embodiment. Moreover, the outflow of water vapor | steam when the humidity control part 70 is removed can be prevented further effectively.

(Embodiment 5)
FIG. 6 is a schematic side view illustrating the structure of the fuel cell 10 according to the fifth embodiment. FIG. 6A is a schematic diagram of the fuel cell 10 during operation stop. FIG. 6B is a schematic view of the fuel cell 10 in operation. The fuel cell 10 according to the present embodiment is different from the fuel cell 10 according to the first embodiment in that a shielding unit 80 is provided. Unlike the other embodiments, the fuel cell 10 of the present embodiment is a flow type fuel cell in which a dead-end space is not formed during operation of the fuel cell 10. Although omitted in the figure, in the fuel cell 10 according to the present embodiment, the hydrogen supply unit 50 shown in FIG. 1 or 3 is attached via a gas pipe 52.

  The structure of the shielding means 80 is the same as that of the fourth embodiment. In the present embodiment, during operation of the fuel cell 10, the shielding member 84 covers the anode chamber 32 as shown in FIG. 6A, and the anode chamber 32 is not conditioned. On the other hand, during operation stop, in order to adjust the humidity of the anode catalyst layer 24 of the fuel cell 10, the shielding member 84 is accommodated in the accommodation chamber 82 and the anode chamber 32 is covered with the shielding member 84 as shown in FIG. Absent. In this case, the gas pipe 52 and the gas pipe 60 are closed, and a dead end space is formed.

  According to the present embodiment, the humidity of the anode chamber 32 can be easily adjusted while the fuel cell 10 is stopped.

(Embodiment 6)
FIG. 7 is a schematic side view showing the structure of the fuel cell 10 according to the sixth embodiment. FIG. 7A is a schematic diagram of the fuel cell 10 during operation stop. FIG. 7B is a schematic view of the fuel cell 10 in operation. FIG. 7C is a schematic diagram of the fuel cell 10 during the performance recovery of the humidity control aqueous solution 36. In the fuel cell 10 of the present embodiment, the humidity control chamber 34 is separated into two compartments facing the anode chamber 32, and two different types of humidity control aqueous solutions are respectively stored in the two compartments. This is different from the fuel cell 10 according to Embodiment 1 in that the shielding means 80 is provided. In this figure as well, the hydrogen supply unit 50 is omitted as in FIG.

The humidity control chamber 34 is separated into a first section 92 and a second section 94 by a partition 90. The first compartment 92 contains a humidity control aqueous solution 96 for low humidity. The second compartment 94 contains a humidity control aqueous solution 98 for high humidity. As the humidity control aqueous solution 96 for low humidity, for example, an inorganic salt close to cesium fluoride (CsF) at the bottom of the graph is selected from the inorganic salts listed in FIG. On the other hand, as the humidity control aqueous solution 98 for high humidity, an inorganic salt close to potassium sulfate (K ₂ SO ₄ ) at the top of the graph is selected.

  A storage chamber 82 is provided on one side surface of the anode chamber 32. A shielding member 84 is accommodated in the accommodation chamber 82. The shield member 84 is attached to the first roller 86 with one end attached to the extension member 110. The extension member 110 has air permeability. A linear elastic member 112 is attached to the other end of the shielding member 84. The elastic member 112 is fixed on the opposite side surfaces of the anode chamber 32. As a material of the elastic member 112, a bimetal or a shape memory alloy can be preferably used.

  As shown in FIG. 7A, when the operation of the fuel cell 10 is stopped, the elastic member 112 contracts, whereby the shielding member 84 is pulled out from the accommodation chamber 82 and covers the second compartment 94. In this case, the first section 92 is covered with the extending member 110 having air permeability. As shown in FIG. 7B, during the operation of the fuel cell 10, the first roller 86 rotates, the extension member 110 is wound around and the shielding member 84 is moved, so that the shielding member 84 is moved to the first state. Cover the compartment 92. In this case, the elastic member 112 extends, but the elastic member 112 is linear, so that the air permeability of the second section 94 is ensured. As shown in FIG. 7C, when the humidity control performance of the humidity control chamber 34 is restored, the first roller 86 is further rotated and the extension member 110 and the shielding member 84 are wound around the first roller 86, thereby The section 92 and the second section 94 are not covered by the shielding member 84. In this state, using the hydrogen supply unit 50 of FIG. 3 or the heating device 100 with the humidity control unit 70 removed as shown in FIG. These humidity control performances are restored by heating the humidity control aqueous solution 98 for high humidity.

  According to the present embodiment, even when the operating state of the fuel cell 10 and the optimum humidity of the stopped humidity adjusting unit 30 are different, flooding around the cathode catalyst layer 26 is prevented and dryout around the cathode catalyst layer 26 is prevented. It is possible to achieve both prevention and efficiency more efficiently.

  In the present embodiment, a case is shown in which two compartments are provided in the humidity control chamber 34, but there may be three or more compartments. Further, instead of exclusively covering any of the compartments, for example, by partially covering two or more compartments, the humidity of the anode chamber 32 is intermediate between the humidity adjusted by the respective inorganic salts. You may adjust it.

(Embodiment 7)
FIG. 8 is a schematic side view illustrating the structure of the fuel cell 10 and the cathode humidity control device 120 according to the seventh embodiment. FIG. 8A is a schematic diagram of a cathode humidity control device 120 for conditioning the fuel cell 10 and the cathode catalyst layer 26 in operation. FIG. 8B is a schematic side view illustrating a state in which the cathode humidity control device 120 is attached to the fuel cell 10 while the operation is stopped.

  As shown in FIG. 8A, a cathode humidity control device 120 for conditioning the cathode catalyst layer 26 is provided separately from the fuel cell 10. The cathode humidity control device 120 contains a humidity control aqueous solution 122. The cathode humidity control device 120 is provided with a gas-liquid separation means 124. The gas-liquid separation means 124 allows water vapor to pass but not liquid water. As the gas-liquid separation means 124, a gas-liquid separation film similar to the gas-liquid separation means 28 and the gas-liquid separation means 38 of the first embodiment can be used. As shown in FIG. 8C, the cathode humidity control device 120 is attached to the fuel cell 10 in an airtight manner so that the gas-liquid separation unit 124 comes close to the gas-liquid separation unit 28 while the operation of the fuel cell 10 is stopped. In the state, the humidity around the cathode catalyst layer 26 is adjusted.

  According to the present embodiment, the humidity around the cathode catalyst layer 26 can be kept at a predetermined humidity while the operation of the fuel cell 10 is stopped.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added based on the knowledge of those skilled in the art. The form can also be included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 10 Fuel cell, 20 Membrane electrode assembly, 22 Electrolyte membrane, 24 Anode catalyst layer, 26 Cathode catalyst layer, 28, 124 Gas-liquid separation means, 30 Humidity adjustment part, 32 Anode chamber, 34 Humidity adjustment chamber, 36, 96, 98, 122 Humidity control aqueous solution, 38, 40 Gas-liquid separation means, 50 Hydrogen supply part, 52, 56, 60 Gas piping, 54, 58, 62, 64 Valve, 70 Humidity control part, 80 Shielding means, 82 Storage chamber , 84 Shielding member, 86 First roller, 88 Second roller, 90 Partition, 92 First section, 94 Second section, 110 Extension member, 112 Elastic member, 120 Humidity control device for cathode

Claims (6)

A membrane electrode assembly having an electrolyte membrane, an anode catalyst layer provided on one surface of the electrolyte membrane, and a cathode catalyst layer provided on the other surface of the electrolyte membrane;
A humidity control unit in contact with the anode catalyst layer,
The humidity adjusting unit is isolated from the anode catalyst layer by the gas chamber and the gas-liquid separation unit that allows only gas to pass through the anode chamber for supplying hydrogen to the anode catalyst layer and exceeds the saturation amount. A humidity control chamber containing a humidity control aqueous solution containing a predetermined inorganic salt,
The water vapor present in the anode chamber is absorbed by the humidity control aqueous solution, and the water vapor evaporated from the humidity control aqueous solution is supplied to the anode chamber, whereby the humidity of the anode chamber is passed through the gas-liquid separation means. A fuel cell characterized in that is adjusted.   2. The fuel cell according to claim 1, further comprising heating means for evaporating water from the humidity control aqueous solution to the outside of the humidity control chamber by heating.   3. The fuel cell according to claim 2, wherein the heating unit is a hydrogen supply unit provided adjacent to the humidity control chamber and having a hydrogen storage alloy for supplying hydrogen to the humidity control unit. .   The fuel cell according to claim 1, wherein the humidity control chamber is removable.   5. The apparatus according to claim 1, further comprising a shielding unit configured to shield the humidity control chamber during operation of the fuel cell and not to shield the humidity control chamber during stoppage. The fuel cell as described. Further comprising shielding means for shielding the humidity control chamber;
The humidity control chamber is separated into a plurality of compartments facing the anode chamber,
Each of the plurality of compartments contains a plurality of different humidity control aqueous solutions for adjusting the humidity of the anode chamber to different humidity, respectively.
The fuel cell according to any one of claims 1 to 4, wherein the shielding means shields at least a part of the plurality of compartments according to an operating state of the fuel cell.

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