JP5278393B2 - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell causing no deterioration in cooling efficiency or reaction efficiency even if both surfaces of a separator having a blocking passage are used as a passage of a cooling medium or reaction gas. <P>SOLUTION: A fuel cell includes: a power generation cell having an electrolyte membrane; and a separator facing to the power generation cell. A gas passage is formed in a face on the power generation cell side of the separator, wherein a grooved passage having an inlet port blocked by one blocking member and a grooved passage having an outlet port blocked by other blocking member are alternately aligned in stripes in the gas passage. At least one of the blocking members has gas impermeability, and at least one of the blocking members has gas permeability. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fuel cell including a power generation cell and a separator.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. This fuel cell is environmentally superior and can realize high energy efficiency, and therefore has been widely developed as a future energy supply system.

  In this fuel cell, a separator comprising an electrode plate in which a fluid passage for supplying a fuel gas containing hydrogen is formed on both sides of an electrolyte membrane made of a solid polymer or the like, and a fluid for supplying an oxidant gas containing oxygen There is known one provided with a separator made of an electrode plate in which a passage is formed.

  A technique is disclosed in which the gas supply flow path and the gas discharge flow path are separated into a comb shape so as to engage with each other in the separator (see, for example, Patent Document 1). According to this technique, the reaction between the fuel gas and the oxidant gas is efficiently performed in the entire separator reaction zone.

JP-A-11-16591

  However, in the separator described in Patent Document 1, there is a possibility that the fluid flow on the surface opposite to the gas supply channel and the gas discharge channel may be hindered. Hereinafter, this problem will be described.

  FIG. 9 is a diagram illustrating a conventional separator 30 in which comb-shaped channels are formed. FIG. 9A is a plan view of the separator 30, and FIGS. 9B and 9C are cross-sectional views of the fuel cell when the separator 30 is applied to the fuel cell.

  As shown in FIG. 9A, a gas supply channel 31 and a gas discharge channel 32 which are part of a comb-shaped channel are formed on the surface of the separator 30. The reaction gas flows through the gas supply channel 31 and the gas discharge channel 32. The gas supply channel 31 and the gas discharge channel 32 are grooved channels obtained by pressing or the like. If the gas supply channel 31 and the gas discharge channel 32 are formed by pressing or the like, a groove is also formed on the back surface of the separator 30.

  As shown in FIG. 9B, if two separators 30 are stacked so that the gas supply flow paths 31 face each other, the groove on the back surface of the separator 30 can be used as a flow path for the cooling medium to flow. However, as shown in FIG. 9B, a convection portion 33 where the cooling medium convects is generated. Thereby, the cooling efficiency of the fuel cell is lowered.

Further, as shown in FIG. 9 (c), by forming a gas supply channel 31 and the gas discharge passage 32 as the convection section 33 of the cooling medium is not formed, the gas supply passage 31 and the gas discharge channel 32 Convection portions 34 having different depths are generated. Thereby, the power generation efficiency of the fuel cell decreases.

  From the above, if the back surface of the conventional separator 30 having a closed flow path such as a comb-shaped flow path is used as the flow path for the cooling medium or the reaction gas, the convection sections 33 and 34 where the cooling medium or the reaction gas convects. Will occur. As a result, cooling efficiency or reaction efficiency decreases.

  An object of the present invention is to provide a fuel cell in which cooling efficiency or reaction efficiency does not decrease even when both surfaces of a separator having a closed flow path are used as a cooling medium or reaction gas flow path.

A fuel cell according to the present invention includes a power generation cell having an electrolyte membrane, and a separator facing the power generation cell, and a groove-like flow path having a member disposed at an outlet end on a surface on the power generation cell side of the separator, Between the inlet end and the outlet end, there is formed a gas flow path in which the inlet end and the outlet end and a groove-like flow path in which members are arranged at a predetermined interval are alternately arranged in stripes, and the outlet end At least one of the disposed member and the member disposed between the inlet end and the outlet end is a gas-impermeable blocking member, and the remaining is gas-permeable and gas flow porous der having a resistance against is, the porous body in which characterized that you have provided at least one.

  According to the present invention, gas is supplied to the entire power generation cell. As a result, the power generation efficiency of the power generation cell is improved. Further, the closing member can be provided at any position of the gas flow path. Further, if the length of the closing member is adjusted, the amount of gas flowing through the gas flow path can be adjusted, and the gas distribution can be adjusted. Furthermore, no special lamination technique is required when laminating separators. Moreover, even if the flow path of the front and back integrated structure using the stripe-shaped flow path is formed on the surface opposite to the power generation cell, the flow of the fluid flowing through the flow path is not affected.

1 is a schematic cross-sectional perspective view of a fuel cell according to the present invention. It is a figure explaining the detail of a separator. It is a figure explaining the gas pressure of fuel gas or oxidant gas which flows through a gas channel. It is sectional drawing of the fuel cell at the time of applying a separator to a fuel cell. It is a figure explaining the other example of a closure member. It is a figure which shows the example which provided the obstruction | occlusion member in the gas flow path of one separator. It is a figure which shows the example using both obstruction | occlusion members. It is a figure which shows the other example of application of a closure member. It is a figure explaining the conventional separator.

  Hereinafter, the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic cross-sectional perspective view of a fuel cell 100 according to the present invention. As shown in FIG. 1, the fuel cell 100 has a structure in which a plurality of unit cells 20 each provided with a separator 1 are stacked on both sides of a power generation cell 10. The power generation cell 10 has a structure in which the catalyst layer 5 and the gas diffusion layer 4 are sequentially laminated on both surfaces of the electrolyte membrane 6.

  As the electrolyte membrane 6, for example, a solid polymer electrolyte membrane or the like is used. This solid polymer electrolyte membrane is composed of a polymer having proton conductivity. For the catalyst layer 5, a carbon-supported platinum catalyst or the like can be used. For the gas diffusion layer 4, carbon paper or the like excellent in gas permeability and conductivity can be used. The separator 1 is made of a metal plate.

  Hydrogen in the fuel gas supplied from one separator 1 permeates the gas diffusion layer 4 due to the diffusion effect, and is separated into protons and electrons in the catalyst layer 5. This proton moves through the electrolyte membrane 6. Oxygen in the oxidant gas supplied from the other separator 1 permeates the gas diffusion layer 4 due to the diffusion effect, and reacts with protons in the catalyst layer 5 to generate water. Power generation by the power generation cell 10 is performed by the above process. The current obtained by the power generation of the power generation cell 10 is collected by the separator 1.

  FIG. 2 is a diagram illustrating details of the separator 1. 2A is a plan view of the separator 1, FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. 2A, and FIG. 2C is a cross-sectional view taken along line B- of FIG. It is B 'sectional view. As shown in FIG. 2A, a gas flow path 2 through which fuel gas or oxidant gas flows is formed on the surface of the separator 1 on the gas diffusion layer 4 side. The gas flow path 2 has a structure in which a groove-shaped flow path 2a whose outlet portion is closed by a closing member 3 and a groove-shaped flow path 2b whose inlet portion is closed by a closing member 3 are alternately arranged in a stripe shape. . The gas flow path 2 can be formed by pressing the separator 1 or the like.

  As the closing member 3, a gas-impermeable closing member can be used. For example, ceramics, carbon, metal, and the like can be used, and resins such as fibers, resins, and rubbers can also be used. In particular, materials such as carbon and metal having gas impermeability and conductivity are preferable. The blocking member 3 can be provided in the flow paths 2a and 2b by welding, pressure bonding, or the like.

  Further, as shown in FIG. 2B, the closing member 3 that closes the inlet portion of the flow path 2b closes the entire flow path 2b. Thereby, the fuel gas or oxidant gas supplied to the gas flow path 2 does not flow into the flow path 2b but flows into the flow path 2a. Similarly, as shown in FIG. 2C, the closing member 3 that closes the outlet of the flow path 2a closes the entire flow path 2a. Thereby, the fuel gas or oxidant gas flowing through the gas flow path 2 a does not pass through the closing member 3.

  Further, as shown in FIGS. 2B and 2C, a cooling medium flow path 7 through which a cooling medium for cooling the fuel cell 100 flows is provided on the surface of the separator 1 opposite to the gas diffusion layer 4. A plurality are formed. As the cooling medium, for example, cooling water can be used. The cooling medium flow path 7 is a groove-shaped flow path on the surface opposite to the gas flow path 2 of the separator 1. Thus, since the groove part formed in both surfaces of the separator 1 is used for the flow path 2 and the cooling medium flow path 7, the fuel cell 100 can be reduced in thickness.

  FIG. 3 is a diagram for explaining the gas pressure of the fuel gas or oxidant gas flowing through the gas flow path 2. FIG. 3A is a view for explaining the flow of gas supplied to the gas flow path 2, and FIG. 3B is a view showing the relationship between the flow path position and the gas pressure.

  The fuel gas or oxidant gas supplied to the flow path 2a is used for power generation of the power generation cell 10 of FIG. 1 as it flows through the flow path 2a. As a result, as shown in FIG. 3B, the pressure of the fuel gas or oxidant gas supplied to the flow path 2a decreases as the gas flows.

  Since the inlet portion of the flow path 2b is closed by the closing member 3, fuel gas or oxidant gas is not supplied from the inlet of the flow path 2b. However, since a pressure difference is generated between the flow path 2a and the flow path 2b, the fuel gas or oxidant gas flowing through the flow path 2a passes through the gas diffusion layer 4 and flows into the flow path 2b. The fuel gas or oxidant gas supplied to the flow path 2b is used for power generation of the power generation cell 10 as it flows through the flow path 2b. As a result, as shown in FIG. 3B, the pressure of the fuel gas or oxidant gas flowing in the flow path 2b decreases in the gas flow direction. The fuel gas or the oxidant gas is also used for power generation of the power generation cell 10 when passing through the gas diffusion layer 4. As a result, the pressure of the fuel gas or oxidant gas flowing through the flow path 2b is lower than the pressure of the fuel gas or oxidant gas flowing through the flow path 2a.

  As described above, by providing the closing member 3 in the gas flow path 2, the fuel gas or the oxidant gas is supplied to the entire gas diffusion layer 4. Therefore, the power generation efficiency of the power generation cell 10 is improved. Further, the power generation efficiency of the power generation cell 10 is not affected by the structure of the surface of the separator 1 opposite to the diffusion layer 4.

  Further, since the closing member 3 is provided after the gas flow path 2 is formed by press working or the like, it can be provided at any position of the flow paths 2a and 2b. Furthermore, if the length of the closing member 3 is adjusted, the amount of fuel gas or oxidant gas flowing through the gas flow path 2 can be adjusted, and the distribution of the fuel gas or oxidant gas can be adjusted. . In addition, when laminating the separator 1, no special laminating technique is required.

  FIG. 4 is a cross-sectional view of the fuel cell 100 when the separator 1 is applied to the fuel cell 100. 4A and 4B are cross-sectional views of the fuel cell 100 when the separators 1 are stacked so that the coolant flow paths 7 face each other. Even if the flow path 2a of each separator 1 is turned backward as shown in FIG. 4 (a), the flow path 2a and the flow path 2b of each separator 1 are turned backward as shown in FIG. 4 (b). However, the effect of the present invention can be obtained. In addition, as shown in FIG. 4C, the cooling medium flow path 7 can also be used as the gas flow path 2. In this case, since it is not necessary to stack the separator provided between each power generation cell 10, the fuel cell 100 is reduced in thickness.

  FIG. 5 is a diagram for explaining a closing member 3 a which is another example of the closing member 3. FIG. 5A is a plan view of the separator 1, and FIG. 5B is a cross-sectional view taken along the line C-C 'of FIG.

  As shown in FIGS. 5A and 5B, the closing member 3 a is provided at the same position as the closing member 3. The closing member 3a is made of a porous body having gas permeability. As the porous body, carbon, ceramics, metal mesh, or the like can be used. Moreover, resin, such as a fiber, resin, rubber | gum, etc. can also be used. In particular, conductive carbon, metal mesh, and the like are preferable. However, when a metal mesh is used for the flow path for flowing the oxidant gas, it is preferable to use an oxidation resistant metal such as gold or platinum. The blocking member 3a can be provided in the flow paths 2a and 2b by welding, pressure bonding, or the like. The closing member 3a corresponds to the closing member described in the claims.

  Unlike the closing member 3, the closing member 3a has gas permeability. Thereby, the fuel gas or oxidant gas supplied to the gas flow path 2 also flows into the flow path 2b. Therefore, the pressure loss of the fuel gas or oxidant gas supplied to the gas flow path 2 is reduced. Further, the fuel gas or oxidant gas supplied to the flow path 2a passes through the closing member 3a and is discharged. Thereby, the flooding of the flow path 2a can be suppressed.

  Moreover, since the closing member 3a is a porous body, it has resistance to the flow of fuel gas or oxidant gas. Thereby, a pressure difference arises between the flow path 2a and the flow path 2b similarly to the case where the closing member 3 is provided in the flow paths 2a and 2b. Therefore, as described in FIG. 3, the fuel gas or the oxidant gas is supplied to the entire gas diffusion layer 4. As a result, the power generation efficiency of the power generation cell 10 is improved. Further, the fuel gas or oxidant gas supplied to the gas flow path 2 is supplied to both the flow paths 2a and 2b. Thereby, the flow cross-sectional area of the fuel gas or the oxidant gas is increased. Therefore, the flow rate of the fuel gas or oxidant gas is reduced. As a result, drying of the power generation cell 10 can be suppressed.

  Further, the power generation efficiency of the power generation cell 10 is not affected by the structure of the surface of the separator 1 opposite to the diffusion layer 4. Further, since the closing member 3a is provided after the gas flow path 2 is formed by press working or the like, it can be provided at any position of the flow paths 2a and 2b. Further, by adjusting the length or mesh size of the closing member 3a, the amount of fuel gas or oxidant gas flowing through the gas flow path 2 can be adjusted, and the distribution of the fuel gas or oxidant gas can be adjusted. can do. In addition, when laminating the separator 1, no special laminating technique is required.

  FIG. 6 is a view showing an example in which the blocking members 3 and 3 a are provided in the gas flow path 2 of one separator 1. 6 (a) and 6 (b) show a fuel cell 100 in which closing members 3 and 3a are provided in one gas flow path 2 of an adjacent separator 1. FIG. As described above, the closing members 3 and 3 a may be provided in one gas flow path 2 of the adjacent separator 1. In particular, it is preferable to provide the blocking members 3 and 3a in the gas flow path 2 of the separator 1 to which the oxidant gas is supplied. In this case, oxygen having low diffusibility is efficiently supplied to the diffusion layer 4. Moreover, since it is not necessary to provide the blocking members 3 and 3a in the gas flow path 2 of the separator 1 to which the fuel gas is supplied, the manufacturing cost can be reduced.

  6 (c) and 6 (d), in the case where the gas flow paths 2 are provided on both surfaces of the separator 1, a fuel cell in which the closing members 3 and 3a are provided in any one of the gas flow paths 2. 100 is shown. Thus, when the gas flow path 2 is provided on both surfaces of the separator 1, the blocking members 3 and 3a may be provided in the flow path of one gas flow path. In particular, like the fuel cell 100 in FIGS. 6A and 6B, it is preferable to provide the closing members 3 and 3a in the gas flow path 2 to which the oxidant gas is supplied.

  FIG. 7 is a diagram showing an example in which both the closing member 3 and the closing member 3a are used. FIG. 7A shows a fuel cell 100 in which a closing member 3 is provided in the gas flow path 2 of one separator 1 and a closing member 3 a is provided in the gas flow path 2 of the other separator 1. . For example, the diffusion layer 4 is provided by providing the closing member 3 in the gas flow path 2 of the separator 1 to which the oxidant gas is supplied and providing the closing member 3a in the gas flow path 2 of the separator 1 to which the fuel gas is supplied. In addition, oxygen can be supplied efficiently and flooding due to water generated by the power generation cell 10 can be suppressed.

  7B, in the case where the gas flow paths 2 are provided on both surfaces of the separator 1, the closing member 3 is provided in one gas flow path 2, and the closing member 3a is provided in the other gas flow path 2. A provided fuel cell 100 is shown. For example, by providing the closing member 3 in the gas flow path 2 to which the oxidant gas is supplied and providing the closing member 3a in the gas flow path 2 to which the fuel gas is supplied, oxygen is efficiently supplied to the diffusion layer 4. While being supplied, flooding due to water generated by the power generation cell 10 can be suppressed. The combination of the closing member and the closing member 3a is not limited to that shown in FIGS. 7A and 7B, and can be arbitrarily selected.

FIG. 8 is a diagram illustrating another application example of the blocking members 3 and 3a. FIG. 8A is a diagram showing a case where the closing member 3 provided in the flow path 2b is moved in the gas flow direction, and FIG. 8B shows a case where the length of some of the closing members 3a is changed. FIG.

  As shown in FIG. 8A, the fuel gas or oxidant gas supplied to the gas flow path 2 is supplied to both the flow paths 2a and 2b. Thereby, the flow cross-sectional area in which the fuel gas or the oxidant gas flows is increased. Therefore, the flow rate of the fuel gas or oxidant gas flowing through the flow paths 2a and 2b is reduced. As a result, drying of the power generation cell 10 is suppressed. The same effect can be obtained by using the closing member 3a instead of the closing member 3. Further, the closing member 3 and the closing member 3a can be arbitrarily combined.

  Moreover, as shown in FIG.8 (b), the length of some obstruction | occlusion members 3a differs from the length of the other obstruction | occlusion members 3a. Thereby, the flow volume of the fuel gas or oxidant gas which flows through the gas flow path 2 can be adjusted. For example, the length of the blocking member 3a of the flow paths 2a, 2b that are difficult for fuel gas or oxidant gas to reach is shortened, and the length of the blocking member 3a of the flow paths 2a, 2b that is easily reached by fuel gas or oxidant gas. By making the length longer, the fuel gas or the oxidant gas can be uniformly supplied to the entire gas flow path 2. The same effect can be obtained by using the closing member 3 instead of the closing member 3a. Further, the closing member 3 and the closing member 3a can be arbitrarily combined.

  In this embodiment, the separator 3 is made of a metal plate, but may be any conductive plate having conductivity and gas impermeability. For example, a carbon plate or the like can be used.

  In this embodiment, the separators 3 and 3a are formed by pressing a conductive plate. However, the separators 3 and 3a may be formed by cutting a carbon plate or the like.

DESCRIPTION OF SYMBOLS 1 Separator 2 Gas flow path 2a, 2b Flow path 3, 3a Closing member 4 Gas diffusion layer 5 Catalyst layer 6 Electrolyte membrane 7 Cooling medium flow path 10 Power generation cell 20 Single cell 100 Fuel cell

Claims (2)

A power generation cell having an electrolyte membrane;
A separator facing the power generation cell,
On the surface of the separator on the power generation cell side, a groove-like flow path having a member disposed at the outlet end, and the member at a predetermined interval from the inlet end and the outlet end between the inlet end and the outlet end. Gas flow paths are alternately arranged in a stripe pattern with the groove-shaped flow paths in which are arranged,
At least one of the member disposed at the outlet end and the member disposed between the inlet end and the outlet end is a gas-impermeable blocking member, and the rest has gas permeability. and Ri porous body der having a resistance to the flow of gas, a fuel cell, wherein Rukoto the porous body provided at least one. Of the members disposed at the outlet end and the members disposed between the inlet end and the outlet end, the length in the gas flow direction of at least one gas is the length of the other member in the gas flow direction. The fuel cell according to claim 1, which is different.

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