JP2022180823A - Fuel cell - Google Patents

Abstract

To provide a fuel cell capable of suppressing voltage drop when the fuel cell is restarted after the storage period ends by suppressing poisoning of catalysts by carbonyl compounds during storage of the fuel cell.SOLUTION: A disclosed fuel cell includes: an electrode-membrane conjugate that has an anode electrode that has an anode catalyst layer, a cathode electrode having a cathode catalyst layer, and an electrolyte membrane; an anode separator; an anode side gas seal member; an anode gas diffusion layer placed between the anode separator and the electrode-membrane conjugate; a cathode separator; a cathode side gas seal member; and a cathode gas diffusion layer placed between the cathode separator and the electrode-membrane conjugate, in which a liquid containing a hydride reducing agent that reduces the carbonyl compound is placed.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to fuel cells.

Patent Literature 1 discloses a fuel cell that suppresses a voltage drop at the time of restarting after the end of a storage period. This fuel cell is provided with a method of stopping and storing the fuel cell in which, after power generation is stopped, the fuel cell is stored in a state in which humidified inert gas is sealed in the anode gas channel or the cathode gas channel.

JP-A-6-251788

INDUSTRIAL APPLICABILITY According to the present disclosure, by suppressing poisoning of the catalyst by carbonyl compounds contained in the components of the fuel cell during storage of the fuel cell, it is possible to suppress voltage drop when the fuel cell is restarted after the end of the storage period. Provide fuel cells.

A fuel cell according to the present disclosure is an electrode-membrane assembly having an anode electrode having an anode catalyst layer, a cathode electrode having a cathode catalyst layer, and an electrolyte membrane disposed between the anode electrode and the cathode electrode. an anode separator facing the anode electrode, an anode-side gas seal member sealing between the anode separator and the electrode-membrane assembly, and between the anode separator and the electrode-membrane assembly an anode gas diffusion layer disposed; a cathode separator facing the cathode electrode; a cathode-side gas seal member sealing between the cathode separator and the electrode-membrane assembly; a cathode gas diffusion layer disposed between the membrane assembly and a liquid containing a hydride reducing agent that reduces a carbonyl compound is disposed therein.

The fuel cell according to the present disclosure reduces the carbonyl compound produced from the peroxide cross-linking agent remaining in the gas seal to alcohol with the hydride reducing agent. Therefore, even when the members constituting the fuel cell contain a carbonyl compound derived from the peroxide cross-linking agent, poisoning of the catalyst layer by the carbonyl compound can be suppressed. Therefore, by suppressing the poisoning of the catalyst during the storage period of the fuel cell, it is possible to suppress the voltage drop when the fuel cell is restarted after the end of the storage period.

1 is an external perspective view showing the configuration of a fuel cell according to Embodiment 1. FIG. Cross-sectional view of the fuel cell in Embodiment 1 taken along line AA in FIG. Cross-sectional view of the cell stack of the fuel cell in Embodiment 1 Sectional view of the cell unit of the fuel cell according to Embodiment 1 Sectional view of a cell unit of a fuel cell according to Embodiment 2 Sectional view of a cell unit of a fuel cell according to Embodiment 3 Sectional view of a cell unit of a fuel cell according to Embodiment 4

(Knowledge, etc. on which this disclosure is based)
At the time when the inventors came up with the present disclosure, an electrode-membrane assembly having an anode catalyst layer, a cathode catalyst layer, and a polymer electrolyte membrane as an electrolyte was sandwiched between separators in which gas channels were formed. There was technology to form fuel cells. In this fuel cell, a gas seal is arranged between the electrode-membrane assembly and the separator to suppress gas leakage to the outside of the system.
This fuel cell has a structure in which an electrochemical reaction between a hydrogen-containing gas and air proceeds by the catalytic action of catalyst layers provided on the anode and cathode, respectively, and electrons are extracted to an external circuit.
However, when the fuel cell is stored in a state where power generation is stopped, when the fuel cell is restarted after the end of the storage period, the voltage may drop compared to before the power generation is stopped. The inventors searched for factors that cause this phenomenon. The inventors have found that when a peroxide cross-linking agent is used as a cross-linking agent for the rubber material constituting the gas seal in the gas seal manufacturing process, decomposition products of the cross-linking agent are added to the rubber material of the gas seal after manufacturing. It was discovered that a carbonyl compound remained. Furthermore, the inventors found that the carbonyl compound gradually eluted from the gas seal during the storage period, adsorbed to the platinum surface of the catalyst layer and poisoned it, and when the fuel cell was restarted after the storage period ended, electrochemical The present inventors have discovered the problem of inhibiting the reaction to lower the power generation voltage, and have come to constitute the main subject of the present disclosure in order to solve the problem.
Therefore, the present disclosure suppresses the poisoning of the catalyst by the carbonyl compound contained in the components of the fuel cell during storage of the fuel cell, thereby preventing the voltage drop when the fuel cell is restarted after the end of the storage period. To provide a fuel cell that can be suppressed.

Hereinafter, embodiments will be described in detail with reference to the drawings. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters or redundant descriptions of substantially the same configurations may be omitted.
It should be noted that the accompanying drawings and the following description are provided for a thorough understanding of the present disclosure by the parties and are not intended to limit the claimed subject matter thereby.

(Embodiment 1)
Embodiment 1 will be described below with reference to FIGS. 1 to 4. FIG.

[1-1. Configuration of fuel cell]
FIG. 1 is an external perspective view showing the configuration of a fuel cell 90 according to Embodiment 1 of the present invention. FIG. 2 is a cross-sectional view of the fuel cell 90 according to Embodiment 1 of the present invention taken along line AA of FIG. FIG. 3 is a cross-sectional view of the cell laminate 3 according to Embodiment 1 of the present invention taken along line AA of FIG.

As shown in FIG. 1, a fuel cell 90 of the present embodiment has a structure in which a stack portion 2 in which cells are stacked is sandwiched between collector plates 60 and 61 . End plates 70 and 77 are arranged outside the stack portion 2 , and a bolt 80 is arranged across the end plates 70 and 77 . The bolts 80 press the collector plates 60 and 61 and the stack section 2 by fastening the end plates 70 and 77 .

A fuel gas inlet 71, a fuel gas outlet 72, an oxidizing gas inlet 73, an oxidizing gas outlet 74, a cooling medium inlet 75, and a cooling medium outlet 76 are provided on the upper surface of the end plate 70. . The fuel gas introduction port 71 introduces the fuel gas into the stack section 2, and the fuel gas discharge port 72 discharges the fuel gas. The oxidizing gas inlet 73 introduces the oxidizing gas into the stack section 2, and the oxidizing gas outlet 74 discharges the oxidizing gas. The cooling medium inlet 75 introduces the cooling medium into the stack section 2 . The cooling medium discharge port 76 discharges the cooling medium. The fuel gas is hydrogen or a gas containing hydrogen. The oxidant gas is a gas containing oxygen, specifically air. The cooling medium is a fluid such as ion-exchanged water.

As shown in FIG. 3, the cell stack 3 of the present embodiment is constructed by stacking a plurality of cell units 4 and cooling separators 38 . The cell unit 4 has a structure in which an electrode-membrane-frame assembly 10 (electrode-membrane assembly) is sandwiched between an anode separator 31 and a cathode separator 35 .

As will be described later, the anode separator 31 is formed with a fuel gas channel through which the fuel gas flows, and the cathode separator 35 is formed with an oxidant gas channel through which the oxidant gas flows. The cooling separator 38 is formed with a cooling medium channel through which the cooling medium flows.

In this embodiment, an example in which the cooling separator 38 is configured as a separate member from the anode separator 31 and the cathode separator 35 will be described, but this is just an example. The cooling separator 38 may be configured integrally with the anode separator 31 . In this case, the anode separator 31 has a configuration in which a fuel gas channel is formed on one main surface facing the anode electrode of the electrode-membrane-frame assembly 10, and a cooling medium channel is formed on the other main surface. Become. Alternatively, the cooling separator 38 may be constructed integrally with the cathode separator 35 . In this case, the cathode separator 35 has an oxidant gas channel formed on one main surface facing the cathode electrode of the electrode-membrane-frame assembly 10, and a cooling medium channel formed on the other main surface. becomes.

[1-2. Cell configuration]
As shown in FIG. 4, the cell unit 4 of this embodiment has an electrode-membrane-frame assembly 10, an anode separator 31, and a cathode separator .

The electrode-membrane-frame assembly 10 includes an electrolyte membrane 15, an anode catalyst layer 16 arranged on one main surface with the electrolyte membrane 15 interposed therebetween, a cathode catalyst layer 17 arranged on the other main surface, an anode A gas diffusion layer 20 (anode gas diffusion layer) arranged outside the catalyst layer 16 , a gas diffusion layer 22 (cathode gas diffusion layer) arranged outside the cathode catalyst layer 17 , and a frame 19 . . The gas diffusion layer 20 is arranged on the side opposite to the electrolyte membrane 15 with the anode catalyst layer 16 interposed therebetween. The gas diffusion layer 22 is arranged on the side opposite to the electrolyte membrane 15 with the cathode catalyst layer 17 interposed therebetween.

The anode catalyst layer 16 and gas diffusion layer 20 constitute an anode electrode 51 . An anode separator 31 is arranged facing the anode electrode 51 . The cathode catalyst layer 17 and gas diffusion layer 22 constitute the cathode electrode 52 . A cathode separator 35 is arranged to face the cathode electrode 52 .

The fuel cell 90 of the present embodiment is a polymer electrolyte fuel cell using the electrolyte membrane 15, which is a polymer electrolyte membrane, as an electrolyte.
The electrolyte membrane 15 is a polymer electrolyte membrane having hydrogen ion conductivity, and is specifically made of a perfluorosulfonic acid-based polymer material having sulfonic acid groups as hydrogen ion exchange groups. The electrolyte membrane 15 transports hydrogen ions generated in the anode catalyst layer 16 to the cathode catalyst layer 17 .

The anode catalyst layer 16 is a layer containing a catalyst for oxidation reaction of hydrogen, and specifically contains carbon particles supporting platinum (Pt) and a polymer electrolyte resin. A fuel gas is supplied to the anode catalyst layer 16 through a fuel gas channel 32 formed in the anode separator 31 . The catalyst contained in the anode catalyst layer 16 promotes an electrochemical reaction that dissociates hydrogen contained in the fuel gas into hydrogen ions.

The cathode catalyst layer 17 is a layer containing a catalyst for a reduction reaction of oxygen, and specifically contains carbon particles supporting platinum and a polymer electrolyte resin. An oxidant gas is supplied to the cathode catalyst layer 17 through an oxidant gas channel 36 formed in the cathode separator 35 . The catalyst contained in the cathode catalyst layer 17 promotes an electrochemical reaction that produces water from hydrogen ions that move from the anode catalyst layer 16 through the electrolyte membrane 15 to the cathode catalyst layer 17 and oxygen contained in the oxidant gas. .

The gas diffusion layer 20 is arranged in contact with the anode catalyst layer 16 . The gas diffusion layer 20 has a function of diffusing the fuel gas supplied from the fuel gas channel 32 and supplying it to the anode catalyst layer 16 and a function of transferring electrons to and from the anode catalyst layer 16 .
The gas diffusion layer 22 is arranged in contact with the cathode catalyst layer 17 . The gas diffusion layer 22 has a function of diffusing the oxidant gas supplied from the oxidant gas channel 36 and supplying it to the cathode catalyst layer 17 and a function of giving and receiving electrons to and from the cathode catalyst layer 17 . .

The gas diffusion layer 20 and the gas diffusion layer 22 are mainly composed of conductive carbon paper having both gas permeability and electronic conductivity. For example, the gas diffusion layers 20 and 22 may have a configuration in which a water-repellent polymer resin typified by fluororesin is dispersed in a conductive base material having a porous structure made of carbon paper. .

The anode separator 31 and the cathode separator 35 are plate-like members having mechanical strength and electrical conductivity. The anode separator 31 and the cathode separator 35 preferably have no gas permeability. The anode separator 31 and cathode separator 35 may be composed of compressed carbon, for example. Alternatively, the anode separator 31 and the cathode separator 35 may be members manufactured by heat-molding a kneaded mixture of graphite powder and thermosetting resin.

The frame 19 is a member made of a non-conductive material, and is formed in the shape of a frame around the outer peripheral region of the electrolyte membrane 15 . Specifically, the frame 19 is made of a resin material, and is preferably made of a hard resin material having mechanical strength from the viewpoint of handling.

The frame 19 is arranged to surround the electrolyte membrane 15 , the anode catalyst layer 16 , the cathode catalyst layer 17 , and the gas diffusion layers 20 and 22 . The frame 19 supports the electrode-membrane-frame assembly 10 so as to cover the electrolyte membrane 15 exposed at the outer periphery of the electrode-membrane-frame assembly 10 .

The anode separator 31 and the cathode separator 35 are rectangular plate members as shown in FIG. The shapes of the electrolyte membrane 15, anode catalyst layer 16, cathode catalyst layer 17, gas diffusion layer 20, and gas diffusion layer 22 are not particularly limited, but in a preferred embodiment, they are rectangular sheet-like or plate-like members. The size of the electrolyte membrane 15 , the anode catalyst layer 16 , the cathode catalyst layer 17 , and the gas diffusion layers 20 and 22 in plan view is smaller than the anode separator 31 and the cathode separator 35 .
On the other hand, the frame body 19 has the same or similar size as the anode separator 31 and the cathode separator 35 in plan view. Therefore, the electrode-membrane-frame assembly 10 has substantially the same size as the anode separator 31 and the cathode separator 35 in plan view.

A gas seal 41 (anode-side gas seal member) is arranged between the electrode-membrane-frame assembly 10 and the anode separator 31 so as to surround the gas diffusion layer 20 . Specifically, the gas seal 41 is arranged on the periphery of the anode separator 31 . The gas seal 41 is a frame-shaped elastic body made of flexible resin, synthetic rubber, or the like. The gas seal 41 seals between the anode separator 31 and the frame 19 to block or suppress leakage of the fuel gas to the outside.

A gas seal 42 (cathode-side gas seal member) is arranged between the electrode-membrane-frame assembly 10 and the cathode separator 35 so as to surround the gas diffusion layer 22 . Specifically, the gas seal 42 is arranged on the periphery of the cathode separator 35 . The gas seal 42 is a frame-shaped elastic body made of flexible resin, synthetic rubber, or the like, and seals between the cathode separator 35 and the frame 19 to block or suppress leakage of the oxidant gas. do.

[1-3. Effect of cross-linking agent on gas seal]
Various synthetic resins and synthetic rubbers can be used for the gas seals 41 and 42 . Specifically, as materials for the gas seals 41 and 42, thermoplastic elastomers such as silicone rubber, natural rubber, polystyrene, polyolefin, polyester, and polyamide, fluororubber, and the like can be used. Preferably, the gas seals 41 and 42 are made of fluororubber, which is excellent in durability when incorporated into the fuel cell 90 . The fluororubber may be vinylidene fluoride (FKM), tetrafluoroethylene-propylene (FEPM), or tetrafluoroethylene-purple vinyl ether (FFKM).

An organic peroxide cross-linking agent is sometimes used as a cross-linking agent for synthetic rubber. Synthetic rubber parts manufactured using an organic peroxide cross-linking agent contain decomposition products generated by thermal decomposition of the organic peroxide cross-linking agent. Products manufactured with dicumyl peroxide (DCP), dibenzoyl peroxide, di(4-methylbenzoyl) peroxide (PMB) as crosslinkers contain aromatic carbonyl compounds as decomposition products of the crosslinker. More specifically, synthetic rubber products manufactured using dicumyl peroxide (bis(1-methyl-1-phenylethyl)=peroxide, DCP) as an organic peroxide cross-linking agent contain carbonyl compounds. . Here, dicumyl peroxide is another name for bis(1-methyl-1-phenylethyl) peroxide. As a specific example, dicumyl peroxide is used as a cross-linking agent for fluororubber.

The inventors have found that when the carbonyl compounds contained in the gas seals 41 and 42, especially the aromatic carbonyl compounds, adhere to the platinum contained in the anode catalyst layer 16 and the cathode catalyst layer 17, the platinum is poisoned and in the fuel gas. It has been found that this hinders the electrochemical reaction between hydrogen and air, and is a factor in lowering the power generation voltage.

That is, when an organic peroxide cross-linking agent is used as a cross-linking agent in manufacturing the gas seals 41 and 42, a carbonyl compound is produced by thermal decomposition of the cross-linking agent. This carbonyl compound remains in the gas seals 41 and 42 after manufacture, is released little by little over a long period of time, and diffuses inside the fuel cell 90 . When the power generation operation of the fuel cell 90 is stopped and the fuel cell 90 is stored, the fuel gas and the oxidant gas do not flow into the fuel cell 90 during the storage period. Therefore, part of the carbonyl compound released from the gas seal 41 moves in the space sealed by the gas seal 41 and the frame 19, passes through the gas diffusion layer 20, and reaches the platinum surface of the anode catalyst layer 16. Adhere to. Similarly, part of the carbonyl compound released from the gas seal 42 adheres to the platinum surface of the cathode catalyst layer 17 via the gas diffusion layer 22 . As the storage period of the fuel cell 90 becomes longer, the amount of carbonyl compounds adhering to the platinum surface increases and the poisoning progresses. Due to the poisoning of platinum, when the fuel cell 90 is restarted after the end of the storage period, the power generation voltage may be lower than before power generation is stopped.
In contrast, in the cell unit 4 of the present embodiment, poisoning of the anode catalyst layer 16 and the cathode catalyst layer 17 can be suppressed by disposing the liquid containing the hydride reducing agent.

[1-4. Liquid containing hydride reducing agent]
As shown in FIG. 4, the working liquid 8 is placed in the cell unit 4 . The working liquid 8 is a liquid containing a hydride reducing agent. More specifically, working liquid 8 is a mixture of liquid and hydride reducing agent. The hydride reducing agent may be any substance that performs hydride reduction of an organic carbonyl compound to an alcohol. Specifically, any substance may be used as long as it reacts with a carbonyl compound, which is a decomposition product of the organic peroxide cross-linking agent, to generate an alcohol. Preferred examples of hydride reducing agents include metal hydrides, transition metal hydride complexes, and metal-free hydride donors. Examples of metal hydrides include aluminum hydride, lithium aluminum hydride, and sodium borohydride. Examples of transition metal hydride complexes include triphenylphosphine rhodium complexes, phosphine-ethylenediamine-ruthenium complexes. Examples of metal-free hydride donors include aluminum isopropoxide.

The liquid that is the main component of the working liquid 8 is selected from water, ethanol and other organic solvents. The hydride reducing agent and the liquid are preferably selected in combinations that do not react with each other. For example, regardless of the type of hydride reducing agent, ethanol, n-propyl alcohol, isopropyl alcohol, and other organic solvents can be selected as the liquid. Other organic solvents are, for example, ether solvents and saturated aliphatic hydrocarbons. Examples of ether solvents include diethyl ether, dimethyl ether, ethyl methyl ether, tetrahydrofuran (THF), 1,2-dimethoxyethane (DME). Examples of saturated aliphatic hydrocarbons include linear alkanes such as n-pentane and n-hexane, and structural isomers thereof. Structural isomers include branched hydrocarbons such as isohexane and isomers having a cyclic structure such as cyclohexane. The working liquid 8 may be a mixture of several of the liquids listed above. For example, working liquid 8 may comprise a mixture of water and ethanol.

In the working liquid 8, the hydride reducing agent may be dissolved in the liquid. The working liquid 8 may also be in a state in which a solid hydride reducing agent is mixed with the liquid. Moreover, the state in which the hydride reducing agent is dissolved in the liquid and the state in which the solid hydride reducing agent is mixed with the liquid may coexist.

Specific examples of the working liquid 8 in which a solid hydride reducing agent is mixed with a liquid include a state in which particles or powder containing the hydride reducing agent are dispersed in a liquid, and a paste containing the hydride reducing agent. The particles and powder of the hydride reducing agent may be particles or powder of the hydride reducing agent, or may be formed into particles or powder by mixing the hydride reducing agent with a base material or a binder. . They may also be formed through a sintering process.

As shown in FIG. 4 , working liquid 8 is placed on both anode electrode 51 and cathode electrode 52 in cell unit 4 of the first embodiment.
In the anode electrode 51 , the working liquid 8 is arranged in a space sealed by the frame 19 , the anode separator 31 and the gas seal 41 . For example, working liquid 8 exists between gas seal 41 and gas diffusion layer 20 and in fuel gas flow path 32 . The working liquid 8 adheres to the surfaces of the frame 19, the anode separator 31, and the gas seal 41, for example. The working liquid 8 may also be located between the anode separator 31 and the anode catalyst layer 16 and infiltrate the gas diffusion layer 20 . The working liquid 8 may also be in the space between the gas diffusion layer 20 and the gas seal 41 . The working liquid 8 may be a mist floating in space. The working liquid 8 may be able to flow through said space. The amount of working liquid 8 is less than the amount that fills the space. In the above space, portions other than the working liquid 8 may be filled with fuel gas, or inert gas may be present. Argon gas, helium gas, nitrogen gas, or the like can be used as the inert gas.

In the cathode electrode 52 , the working liquid 8 is arranged in a space sealed by the frame 19 , the cathode separator 35 and the gas seal 42 . For example, working liquid 8 exists between gas seal 42 and gas diffusion layer 22 and in oxidant gas flow path 36 . The working liquid 8 adheres to the surfaces of the frame 19, the cathode separator 35, and the gas seal 42, for example. The working liquid 8 may also be located between the cathode separator 35 and the cathode catalyst layer 17 and infiltrate the gas diffusion layer 22 . The working liquid 8 may also be in the space between the gas diffusion layer 22 and the gas seal 42 . The working liquid 8 may be mist-like and float in the space, or may permeate the gas diffusion layer 20 . The working liquid 8 may also be movable in the space. The amount of working liquid 8 is less than the amount that fills the space. In the above space, the portion other than the working liquid 8 may be filled with an oxidant gas, or an inert gas may exist.

[1-5. Action of hydride reducing agent]
The carbonyl compound released from the gas seal 41 in the anode electrode 51 diffuses into the space sealed by the gas seal 41 . This carbonyl compound contacts the hydride reducing agent contained in the working liquid 8 and is reduced to alcohol. This suppresses platinum poisoning of the anode catalyst layer 16 .

The carbonyl compound released from the gas seal 42 at the cathode electrode 52 diffuses into the space sealed by the gas seal 42 . This carbonyl compound comes into contact with the hydride reducing agent carried on the trap layer 23 and is reduced to alcohol. This suppresses platinum poisoning of the cathode catalyst layer 17 .

The configuration shown in FIG. 4 can be realized, for example, by injecting the working liquid 8 from the fuel gas inlet 71 and the oxidant gas inlet 73 when starting storage of the fuel cell 90 . In this case, the surplus working liquid 8 may be discharged from the fuel gas discharge port 72 and the oxidant gas discharge port 74 . Further, the working liquid 8 may be injected into the fuel gas inlet 71 together with the gas so that the working liquid 8 spreads over each cell unit 4 constituting the fuel cell 90 . Similarly, the working liquid 8 may be injected together with the gas at the oxidant gas inlet 73 . Here, the gas injected together with the working liquid 8 includes air and inert gas.

[1-6. effects, etc.]
As described above, in the present embodiment, the fuel cell 90 includes the electrode-membrane-frame assembly 10, the anode separator 31, the cathode separator 35, the gas seals 41 and 42, and the gas diffusion layers 20 and 22. , provided. The electrode-membrane-frame assembly 10 includes an anode electrode 51 having an anode catalyst layer 16, a cathode electrode 52 having a cathode catalyst layer 17, and an electrolyte membrane 15 disposed between the anode electrode 51 and the cathode electrode 52. , has The anode separator 31 faces the anode electrode 51 . A gas seal 41 seals between the anode separator 31 and the electrode-membrane-frame assembly 10 . The gas diffusion layer 20 is arranged between the anode separator 31 and the electrode-membrane-frame assembly 10 . Cathode separator 35 faces cathode electrode 52 . A gas seal 42 seals between the cathode separator 35 and the electrode-membrane-frame assembly 10 . The gas diffusion layer 22 is arranged between the cathode separator 35 and the electrode-membrane-frame assembly 10 . A working liquid 8 containing a hydride reducing agent that reduces carbonyl compounds is disposed in the fuel cell 90 .

According to this configuration, when a carbonyl compound is released from the components constituting the fuel cell 90 at the anode electrode 51 and/or the cathode electrode 52, the carbonyl compound is reduced to alcohol by the hydride reducing agent. Thereby, the poisoning of the catalyst by the carbonyl compound can be suppressed.
As a result, even if the members constituting the fuel cell 90 contain a carbonyl compound derived from the peroxide cross-linking agent, poisoning of the catalyst during storage of the fuel cell 90 can be suppressed. Therefore, when the fuel cell 90 is restarted after the end of storage, it is possible to suppress the drop in the generated voltage due to the poisoning of the catalyst. Moreover, even if the members constituting the fuel cell 90 do not contain a carbonyl compound, the presence of the hydride reducing agent does not impair the function of the fuel cell 90 .

In fuel cell 90, working liquid 8 containing a hydride reducing agent may be disposed between anode separator 31 and anode catalyst layer 16 and/or between cathode separator 35 and cathode catalyst layer 17. . According to this configuration, when a carbonyl compound is released from at least one of the gas seal 41 and the gas seal 42, poisoning of the catalyst can be suppressed by reducing the carbonyl compound to alcohol.

In the cell unit 4 of Embodiment 1, the working liquid 8 is placed on both the anode side and the cathode side of the electrolyte membrane 15 in the space surrounded by the anode separator 31, the cathode separator 35, the frame 19, and the gas seals 41 and 42. are placed. According to this configuration, poisoning of the catalyst by the carbonyl compound can be suppressed in both the space on the anode side and the space on the cathode side of the electrolyte membrane 15 . Therefore, it is possible to more effectively suppress the voltage drop when the fuel cell 90 is restarted after the end of storage.

The configurations in which the working liquid 8 is placed either between the anode separator 31 and the anode catalyst layer 16 or between the cathode separator 35 and the cathode catalyst layer 17 are the same as in the second and third embodiments. will explain.

The hydride reducing agent contained in working liquid 8 may be a metal hydride. The hydride reducing agent contained in working liquid 8 may be a metal-free hydride donor. Also, the hydride reducing agent contained in the working liquid 8 may be a transition metal hydride complex.

To more reliably reduce carbonyl compounds released from the gas seals 41, 42, etc. before reaching the anode catalyst layer 16 and/or the cathode catalyst layer 17 when a hydride reducing agent having a strong reducing action is used. is possible, and the poisoning of the catalyst can be suppressed. Further, when using a hydride reducing agent that does not easily react with water, water can be used as the main component of the working liquid 8 . Therefore, there is an advantage that the working liquid 8 can be easily handled.

(Embodiment 2)
Embodiment 2 will be described below with reference to FIG.

[2-1. Constitution]
FIG. 5 is a cross-sectional view showing the configuration of the cell unit 5 that constitutes the fuel cell 90. As shown in FIG. Like the cell unit 4, the cell unit 5 includes an electrode-membrane-frame assembly 10, gas diffusion layers 20 and 22, an anode separator 31, a cathode separator 35, and gas seals 41 and 42. be provided instead. Among the configurations and functions of the cell unit 5, descriptions of configurations and functions common to those of the first embodiment are omitted.

In cell unit 5 , working liquid 8 is arranged on the cathode side of electrolyte membrane 15 . Specifically, the working liquid 8 is placed in the space surrounded by the electrode-membrane-frame assembly 10 , frame 19 , cathode separator 35 and gas seal 42 . In contrast, the working liquid 8 is not arranged on the anode side of the electrolyte membrane 15 .

The configuration shown in FIG. 5 can be realized, for example, by injecting the working liquid 8 from the oxidant gas introduction port 73 when starting storage of the fuel cell 90 . In this case, the surplus working liquid 8 may be discharged from the oxidizing gas discharge port 74 . Further, the working liquid 8 may be injected together with the gas from the oxidizing gas introduction port 73 so that the working liquid 8 spreads over each cell unit 5 constituting the fuel cell 90 . Furthermore, when starting to store the fuel cell 90 , air or inert gas may be injected from the fuel gas inlet 71 .

[2-2. effects, etc.]
A working liquid 8 containing a hydride reducing agent that reduces carbonyl compounds is disposed in the fuel cell 90 . In the cell unit 5 of Embodiment 2, the working liquid 8 is arranged between the gas seal 42 and the gas diffusion layer 22 in the region between the cathode separator 35 and the cathode catalyst layer 17 .
According to this configuration, when a carbonyl compound is released from the gas seal 42, the poisoning of the catalyst in the space on the cathode side of the electrolyte membrane 15 can be suppressed by reducing the carbonyl compound to alcohol. Therefore, it is possible to effectively suppress a voltage drop when the fuel cell 90 is restarted after the end of storage.

(Embodiment 3)
Embodiment 3 will be described below with reference to FIG.

[3-1. Constitution]
FIG. 6 is a cross-sectional view showing the configuration of the cell unit 6 that constitutes the fuel cell 90. As shown in FIG. The cell unit 6 is provided in the fuel cell 90 in place of the cell unit 4 described in the first embodiment or the cell unit 5 described in the second embodiment.

The cell unit 6, like the cell unit 4, comprises an electrode-membrane-frame assembly 10, gas diffusion layers 20, 22, an anode separator 31, a cathode separator 35, and gas seals 41, . Among the configurations and functions of the cell unit 5, descriptions of configurations and functions common to those in the first and second embodiments are omitted.

In cell unit 6 , working liquid 8 is arranged on the anode side of electrolyte membrane 15 . Specifically, the working liquid 8 is placed in a space surrounded by the electrode-membrane-frame assembly 10 , frame 19 , anode separator 31 and gas seal 41 . In contrast, the working liquid 8 is not arranged on the cathode side of the electrolyte membrane 15 .

The configuration shown in FIG. 6 can be realized, for example, by injecting the working liquid 8 from the fuel gas inlet 71 when starting storage of the fuel cell 90 . In this case, the surplus working liquid 8 may be discharged from the fuel gas discharge port 72 . Alternatively, the working liquid 8 may be injected together with the gas from the fuel gas inlet 71 so that the working liquid 8 spreads over each cell unit 6 constituting the fuel cell 90 .
Furthermore, when starting to store the fuel cell 90 , air or inert gas may be injected from the oxidant gas inlet 73 .

[3-2. effects, etc.]
A working liquid 8 containing a hydride reducing agent that reduces carbonyl compounds is disposed in the fuel cell 90 . In the cell unit 6 of Embodiment 3, the working liquid 8 is arranged between the gas seal 41 and the gas diffusion layer 20 in the region between the anode separator 31 and the anode catalyst layer 16 .
According to this configuration, when a carbonyl compound is released from the gas seal 41, the poisoning of the catalyst in the space on the anode side of the electrolyte membrane 15 can be suppressed by reducing the carbonyl compound to alcohol. Therefore, it is possible to effectively suppress a voltage drop when the fuel cell 90 is restarted after the end of storage.

(Embodiment 4)
Embodiment 4 will be described below with reference to FIG.

[4-1. Constitution]
FIG. 7 is a cross-sectional view showing the configuration of the cell unit 7 that constitutes the fuel cell 90. As shown in FIG. The cell unit 7 is provided in the fuel cell 90 in place of the cell unit 4 described in the first embodiment, the cell unit 5 described in the second embodiment, or the cell unit 6 described in the third embodiment.

The cell unit 7, like the cell unit 4, comprises an electrode-membrane-frame assembly 10, gas diffusion layers 20, 22, an anode separator 31, a cathode separator 35, and gas seals 41, . Among the configurations and functions of the cell unit 7, descriptions of configurations and functions common to those of the first to third embodiments are omitted.

In the cell unit 7 , the working liquid 8 fills the space on the anode side and the cathode side of the electrolyte membrane 15 . Specifically, the space on the anode side surrounded by the anode catalyst layer 16 , the frame 19 , the anode separator 31 and the gas seal 41 is filled with the working liquid 8 . Also, the cathode-side space surrounded by the cathode catalyst layer 17 , the frame 19 , the cathode separator 35 , and the gas seal 42 is filled with the working liquid 8 . The working liquid 8 that fills the spaces on the anode and cathode sides contains a hydride reducing agent, as described above.

The configuration shown in FIG. 7 can be realized, for example, by injecting the working liquid 8 from the fuel gas inlet 71 and the oxidant gas inlet 73 when starting storage of the fuel cell 90 . In this case, by injecting the working liquid 8 until the surplus working liquid 8 is discharged from the fuel gas discharge port 72 and the oxidant gas discharge port 74, the fuel gas and the oxidant gas inside the fuel cell 90 are discharged to the working state. It may be completely replaced by the liquid 8.

[4-2. effects, etc.]
A working liquid 8 containing a hydride reducing agent that reduces carbonyl compounds is disposed in the fuel cell 90 . In the cell unit 7 of Embodiment 4, the working liquid 8 is arranged so as to fill the space of the cell unit 7 . That is, the inside of the fuel cell 90 is filled with the working liquid 8 .
According to this configuration, when the carbonyl compounds are released from the gas seals 41 and 42, the carbonyl compounds are quickly reduced to alcohol, and the carbonyl compounds do not reach the anode catalyst layer 16 and the cathode catalyst layer 17. Therefore, the poisoning of the catalyst can be effectively suppressed, and the voltage drop when the fuel cell 90 is restarted after the end of storage can be suppressed.

[5. Storage method of fuel cell]
The configurations disclosed in Embodiments 1 to 4 are applicable when the fuel cell 90 is stored in a shutdown state. That is, by applying Embodiments 1 to 4, it is possible to realize a storage method for the fuel cell 90 that includes an assembly process for producing the fuel cell 90 and an injection process for injecting the working liquid 8 into the fuel cell 90 .

In the assembly process, for example, the cell stack 3 is formed by stacking the electrode-membrane-frame assembly 10, the frame 19, the gas seals 41 and 42, the anode separator 31, the cathode separator 35, and the cooling separator 38. . Also, the stack portion 2 is formed by stacking the cell laminates 3 . Furthermore, in the assembling process, the current collector plates 60 and 61 and the end plates 70 and 77 are attached to the stack section 2 and are pressed and fixed by the bolts 80 .

When Embodiment 1 is applied, in the injection step, the working liquid 8 is injected from the fuel gas inlet 71 and the oxidant gas inlet 73 .
When the second embodiment is applied, the working liquid 8 is injected from the oxidant gas introduction port 73 in the injection step. In this case, fuel gas or inert gas may be injected from the fuel gas inlet 71 .
When Embodiment 3 is applied, the working liquid 8 is injected from the fuel gas inlet 71 in the injection step. In this case, an oxidant gas or an inert gas may be injected from the oxidant gas introduction port 73 .
In the above three cases, when injecting the working liquid 8, the working liquid 8 may be injected together with the gas.

When Embodiment 4 is applied, the working liquid 8 is injected from the fuel gas inlet 71 and the oxidant gas inlet 73 in the injection step. In this case, the working liquid 8 may be injected until the working liquid 8 flows out from the fuel gas outlet 72 and the oxidant gas inlet 73 .

An operation step for operating the fuel cell 90 may be included between the assembly step and the injection step. In this operation process, the fuel gas is injected from the fuel gas inlet 71 and the oxidant gas is injected from the oxidant gas inlet 73 to cause the fuel cell 90 to generate power.

If a high viscosity working liquid 8 is used, the working liquid 8 may be placed during the assembly process without the injection process. For example, in the assembly process, the working liquid 8 is applied to the anode separator 31, the cathode separator 35, the gas seals 41, 42, etc., or the working liquid 8 is dropped into the spaces inside the cell units 4, 5, 6. You may

A storage step of storing the fuel cell 90 may be included after the injection step. In this case, a discharge step of discharging the working liquid 8 from the fuel cell 90 may be included after the storage step. In the discharge step, the working liquid 8 is discharged from the fuel gas discharge port 72 and/or the oxidant gas discharge port 74 . In the discharging process, gas may be injected from the fuel gas inlet 71 and/or the oxidizing gas inlet 73 to accelerate the discharge of the working liquid 8 . An operating step for operating the fuel cell 90 may be included after the discharging step. The operating process is a process of using the fuel cell 90 as a power generator after installing the fuel cell 90 in the environment of use. The discharge process may be performed before transporting the fuel cell 90 to the environment of use, or may be performed after the fuel cell 90 is installed.

(Other embodiments)
As described above, Embodiments 1 to 4 have been described as examples of the technology disclosed in the present application. However, since each of the above-described embodiments is for illustrating the technology in the present disclosure, various changes, replacements, additions, omissions, etc. can be made within the scope of claims or equivalents thereof.

For example, the hydride reducing agent and liquid shown in each of the above embodiments are examples, and the configuration of the present disclosure may be realized using materials other than those shown above. Further, it goes without saying that the shape and size of the members constituting the fuel cell 90 can be appropriately changed from each embodiment.

INDUSTRIAL APPLICABILITY By applying the present disclosure to a fuel cell using a solid polymer electrolyte, poisoning of the catalyst during storage of the fuel cell can be suppressed when using components manufactured using a cross-linking agent. As a result, it is possible to suppress the phenomenon in which the generated voltage drops when the fuel cell is restarted after storage is finished. Specifically, the present disclosure is applicable to fuel cells such as fuel cell vehicles and stationary fuel cells.

2 stack part 3 cell laminate 4, 5, 6, 7 cell unit 8 working liquid 10 electrode-membrane-frame assembly (electrode-membrane assembly)
Reference Signs List 15 electrolyte membrane 16 anode catalyst layer 17 cathode catalyst layer 19 frame 20 gas diffusion layer (anode gas diffusion layer)
22 gas diffusion layer (cathode gas diffusion layer)
31 anode separator 32 fuel gas channel 35 cathode separator 36 oxidant gas channel 38 cooling separator 41 gas seal (anode side gas seal)
42 gas seal (cathode side gas seal)
51 anode electrode 52 cathode electrode 60, 61 collector plate 70, 77 end plate 90 fuel cell

Claims (8)

an electrode-membrane assembly comprising an anode electrode having an anode catalyst layer, a cathode electrode having a cathode catalyst layer, and an electrolyte membrane disposed between the anode electrode and the cathode electrode;
an anode separator facing the anode electrode;
an anode-side gas seal member for sealing between the anode separator and the electrode-membrane assembly;
an anode gas diffusion layer disposed between the anode separator and the electrode-membrane assembly;
a cathode separator facing the cathode electrode;
a cathode-side gas seal member for sealing between the cathode separator and the electrode-membrane assembly;
a cathode gas diffusion layer disposed between the cathode separator and the electrode-membrane assembly;
A fuel cell in which a liquid containing a hydride reducing agent that reduces carbonyl compounds is disposed. 2. The fuel cell according to claim 1, wherein the liquid containing said hydride reducing agent is disposed between at least one of said anode separator and said anode catalyst layer and between said cathode separator and said cathode catalyst layer. 2. The fuel cell according to claim 1, wherein the liquid containing the hydride reducing agent is disposed between the anode-side gas seal member and the anode gas diffusion layer in the region between the anode separator and the anode catalyst layer. . 2. The fuel according to claim 1, wherein the liquid containing the hydride reducing agent is disposed between the cathode-side gas seal member and the cathode gas diffusion layer in the region between the cathode separator and the cathode catalyst layer. battery. 2. The fuel cell according to claim 1, wherein the interior of said fuel cell is filled with a liquid containing said hydride reducing agent. 6. The fuel cell of any one of claims 1-5, wherein the hydride reducing agent is a metal hydride. 6. The fuel cell of any one of claims 1-5, wherein the hydride reducing agent is a metal-free hydride donor. 6. The fuel cell of any one of claims 1-5, wherein the hydride reducing agent is a transition metal hydride complex.

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