JP4690688B2 - Fuel cell stack - Google Patents

Description

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. Alternatively, the present invention relates to a fuel cell stack in which a fluid communication hole for flowing any fluid of a reaction gas is formed.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are provided on both sides of an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane is sandwiched between separators. It has a power generation cell. In this type of fuel cell, a predetermined number of power generation cells are usually stacked, and a terminal plate, an insulating plate, and an end plate are disposed at both ends in the stacking direction to constitute a fuel cell stack.

  In this fuel cell, a fuel gas, for example, a gas mainly containing hydrogen (hereinafter also referred to as hydrogen-containing gas) is supplied to the anode side electrode, while an oxidant gas, for example, A gas or air mainly containing oxygen (hereinafter also referred to as oxygen-containing gas) is supplied. In the fuel gas supplied to the anode side electrode, hydrogen is ionized on the electrode catalyst and moves to the cathode side electrode side through the electrolyte membrane. Electrons generated during that time are taken out to an external circuit and used as direct current electric energy.

  In the fuel cell described above, a fuel gas channel for flowing fuel gas to the anode side electrode and an oxidant gas channel for flowing oxidant gas to the cathode side electrode are provided in the plane of each separator. ing. Furthermore, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  Generally, a fuel cell constitutes a so-called internal manifold type fuel cell in which a fluid supply communication hole and a fluid discharge communication hole penetrating in the stacking direction are provided inside a separator. The fuel gas, the oxidant gas, and the cooling medium, which are fluids, are supplied to the fuel gas flow path, the oxidant gas flow path, and the cooling medium flow path from the fluid supply communication holes, and then the fluid discharge communication holes. Have been discharged.

  In this type of internal manifold fuel cell, the terminal plate and the end plate are provided with the fluid supply communication hole and the fluid discharge communication hole as necessary. At that time, in a metal plate (metal part) such as a terminal plate or a metal separator, the generated water or the cooling water comes into contact with each other so that a corrosion current flows easily, and corrosion due to electric corrosion may occur.

  Therefore, for example, the fuel cell cooling structure disclosed in Patent Document 1 includes four fuel cell stacks 1a to 1d connected in series as shown in FIG. The cooling structure is provided with a supply member 2 for supplying a cooling medium to a cooling medium flow path (not shown) provided in each of the fuel cell stacks 1a to 1d.

  The supply member 2 is provided with an inflow pipe 3 through which the cooling medium flows and an outflow pipe 4 through which the cooling medium flows out. Mesh members 5 and 6 made of a conductive material are attached to the inflow pipe 3 and the outflow pipe 4, and the mesh members 5 and 6 are electrically connected by a conductive line 7. The conductive line 7 is connected to a reference electrode 8 having a potential of 0 V via a conductive line 7a and grounded via a conductive line 7b. This prevents corrosion of other equipment connected to the cooling structure or potential leakage to the outside.

Japanese Patent Laid-Open No. 2001-155761 (FIG. 1)

  By the way, in said patent document 1, each fuel cell stack 1a-1d is comprised by connecting several cells in series. For this reason, in particular, a problem has been pointed out that a corrosion current tends to flow on the high potential side, the corrosion current flows through a metal part such as a metal separator, and the metal part is corroded by electric contact.

  The present invention solves this type of problem, and an object of the present invention is to provide a fuel cell stack that can reliably prevent corrosion due to electric corrosion of metal parts with a simple and economical configuration.

  The present invention has an electrolyte / electrode structure in which a pair of electrodes are disposed on both sides of an electrolyte, and the electrolyte / electrode structure and the separator are alternately stacked, and at least a cooling medium penetrates in the stacking direction. Alternatively, the fuel cell stack is formed with a fluid communication hole through which any fluid of the reaction gas flows.

  In the fuel cell stack, at least one separator is provided with a current collector that collects current by contacting a fluid.

  Further, the current collector is preferably a laminated body in which an electrolyte / electrode structure and a separator are alternately laminated, and is disposed at least on the separator on the highest potential side. This is because the corrosion current on the high potential side can be reduced satisfactorily.

  Furthermore, the separator is formed of a metal plate, and a seal member is provided to cover the inner wall of the fluid communication hole, and the current collector is a metal surface portion desired for the fluid communication hole by cutting out a part of the seal member. It is preferable that it is comprised.

  Furthermore, the separator is formed of a metal plate, and a seal member is provided to cover the inner wall of the fluid communication hole. The current collector is joined to the metal surface portion of the metal plate and is desired for the fluid communication hole. It is preferable to be comprised with a member. Moreover, it is preferable that a current collection part has a rust prevention structure.

  Furthermore, the separator is formed of a metal plate, and a seal member is provided to cover the inner wall of the fluid communication hole, and the current collector is preferably provided from a metal surface portion of the metal plate to a part of the seal member. . Furthermore, the current collector is preferably composed of a conductive film, a conductive adhesive, or a conductive paint.

  According to the present invention, since the current collector is provided in the separator and the current collector directly contacts the fluid flowing through the fluid communication hole, the current is forcibly supplied to the current collector via the generated water or the cooling medium. Can flow. As a result, the corrosion current can be effectively reduced, and it is possible to reliably suppress the occurrence of corrosion due to electrolytic corrosion on metal parts with a simple and economical configuration.

  FIG. 1 is a partially exploded perspective view of a fuel cell stack 10 according to the first embodiment of the present invention.

  The fuel cell stack 10 is mounted on a vehicle such as an automobile, for example. The fuel cell stack 10 includes a stacked body 14 in which a plurality of power generation cells 12 are stacked in the direction of arrow A, and terminal plates 16a and 16b and insulating plates 18a and 18b are interposed at both ends of the stacked body 14 in the stacking direction. End plates 20a and 20b are arranged. The end plates 20a and 20b are fastened in the stacking direction by fastening bolts (not shown).

  As shown in FIG. 1 and FIG. 2, each power generation cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 22, and a thin plate-shaped first and second sandwiching the electrolyte membrane / electrode structure 22. Second metal separators (metal plates) 24 and 26 are provided. Instead of the first and second metal separators 24 and 26, for example, a carbon separator may be used.

  As shown in FIG. 1, an oxidant for supplying an oxidant gas, for example, an oxygen-containing gas (air, etc.) to one end edge of the power generation cell 12 in the direction of arrow B in communication with the direction of arrow A. A gas supply communication hole 28a, a cooling medium supply communication hole 30a for supplying a cooling medium such as pure water or ethylene glycol, and a fuel gas discharge communication hole 32b for discharging a fuel gas such as a hydrogen-containing gas are provided. Provided.

  The other end edge of the power generation cell 12 in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas supply communication hole 32a for supplying fuel gas, and the cooling medium discharge communication hole for discharging the cooling medium. 30b and an oxidant gas discharge communication hole 28b for discharging the oxidant gas are provided.

  The electrolyte membrane / electrode structure 22 includes, for example, a solid polymer electrolyte membrane 34 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 36 and a cathode side electrode 38 that sandwich the solid polymer electrolyte membrane 34. With.

  The anode side electrode 36 and the cathode side electrode 38 are uniformly coated on the surface of the gas diffusion layer with a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 34.

  The first metal separator 24 is provided with an oxidant gas flow path 40 that communicates the oxidant gas supply communication hole 28 a and the oxidant gas discharge communication hole 28 b on one surface facing the electrolyte membrane / electrode structure 22. The other surface of the first metal separator 24 is provided with a cooling medium flow path 42 that communicates the cooling medium supply communication hole 30a and the cooling medium discharge communication hole 30b. The oxidant gas flow path 40 and the cooling medium flow path 42 include a plurality of flow path grooves 40a and 42a, respectively.

  A first seal member 45 is integrally provided on both surfaces of the first metal separator 24 by injection molding, coating or the like around the outer peripheral edge of the first metal separator 24. The first seal member 45 covers the oxidant gas supply communication hole 28a, the oxidant gas discharge communication hole 28b, and the oxidant gas flow path 40 on one surface of the first metal separator 24 to prevent leakage of the oxidant gas. Do.

  The first seal member 45 covers the cooling medium supply communication hole 30 a, the cooling medium discharge communication hole 30 b, and the cooling medium flow path 42 on the other surface of the first metal separator 24 to prevent leakage of the cooling medium.

  The first seal member 45 includes an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas discharge communication hole 28b. This prevents the liquid junction of the first metal separator 24 from being covered. The same applies to the second seal member 47 described below.

  The second metal separator 26 is provided with a fuel gas flow path 44 on one surface facing the electrolyte membrane / electrode structure 22, and the fuel gas flow path 44 includes a fuel gas supply communication hole 32 a and a fuel gas discharge communication hole 32 b. Communicate with. The fuel gas channel 44 includes a plurality of channel grooves 44a. On the other surface of the second metal separator 26, a cooling medium flow path 42 is integrally formed so as to overlap the first metal separator 24.

  A second seal member 47 is integrally provided on both surfaces of the second metal separator 26 by injection molding or the like around the outer peripheral edge of the second metal separator 26. The second seal member 47 covers the fuel gas supply communication hole 32 a, the fuel gas discharge communication hole 32 b, and the fuel gas flow path 44 on one surface of the second metal separator 26 to prevent fuel gas from leaking. The second seal member 47 covers the cooling medium supply communication hole 30 a, the cooling medium discharge communication hole 30 b, and the cooling medium flow path 42 on the other surface of the second metal separator 26 and prevents leakage of the cooling medium.

  As shown in FIGS. 1 and 3, on one end side of the end plate 20a in the direction of arrow B, a manifold pipe 46a that communicates with the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, and the fuel gas discharge communication hole 32b. , 48a and 50b are integrally or individually disposed. On the other end side of the end plate 20a in the direction of arrow B, manifold pipes 50a, 48b and 46b communicating with the fuel gas supply communication hole 32a, the cooling medium discharge communication hole 30b and the oxidant gas discharge communication hole 28b are integrated or individually provided. It is arranged.

  As shown in FIG. 3, the laminate 14 includes an end separator (second metal separator) 26 a that is laminated on the terminal plate 16 a on the high potential side (tip end side in the arrow A1 direction). The end separator 26a includes an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas discharge communication hole 28b. A current collector 52 is provided facing at least the lower part of the. The current collector 52 is provided to reduce the high-potential side corrosion current.

  The current collector 52 is provided integrally with the end separator 26a. For example, in the cooling medium supply communication hole 30a, as shown in FIGS. 4 and 5, the second seal member 47 integrally formed (or coated) covering the outer peripheral edge of the end separator 26a is partially formed. Is peeled off. Specifically, a metal surface desired for the cooling medium supply communication hole 30a is formed by cutting out a part of the second seal member 47 forming the convex portion and / or the concave portion constituting the flow channel groove 42a of the cooling medium flow channel 42. The current collecting part 52 which is a part is exposed to the outside. On the surface of the current collecting portion 52, a plating processing portion 54 that functions as a rust prevention structure, for example, by gold plating or platinum plating is provided.

  As shown in FIG. 6, the oxidant gas supply communication hole 28a, the cooling medium supply communication hole 30a, the fuel gas discharge communication hole 32b, the fuel gas supply communication hole 32a, and the cooling medium discharge communication are provided in the terminal plate 16a and the end plate 20a. Insulating grommets 56 and 58 are disposed corresponding to the respective rectangular inner peripheral surfaces of the hole 30b and the oxidizing gas discharge communication hole 28b.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, the oxidant gas is supplied from the manifold pipe 46 a to the oxidant gas supply communication hole 28 a of the fuel cell stack 10. On the other hand, the fuel gas is supplied from the manifold pipe 50 a to the fuel gas supply communication hole 32 a of the fuel cell stack 10. Further, the cooling medium is supplied from the manifold pipe 48 a to the cooling medium supply communication hole 30 a of the fuel cell stack 10.

  In the fuel cell stack 10, an oxidant gas is introduced into the oxidant gas flow path 40 of the first metal separator 24 from the oxidant gas supply communication hole 28 a, and along the cathode side electrode 38 of the electrolyte membrane / electrode structure 22. Move. On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the second metal separator 26 from the fuel gas supply communication hole 32 a and moves along the anode side electrode 36 of the electrolyte membrane / electrode structure 22.

  Therefore, in each electrolyte membrane / electrode structure 22, the oxidant gas supplied to the cathode side electrode 38 and the fuel gas supplied to the anode side electrode 36 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas supplied and consumed to the cathode side electrode 38 flows along the oxidant gas discharge communication hole 28b, and is then discharged to the manifold piping 46b connected to the end plate 20a. Similarly, the fuel gas consumed by being supplied to the anode side electrode 36 is discharged to the fuel gas discharge communication hole 32b, flows, and discharged to the manifold pipe 50b connected to the end plate 20a.

  In addition, a cooling medium such as pure water or ethylene glycol is introduced into the cooling medium flow path 42 between the first and second metal separators 24 and 26 and then flows along the arrow B direction. The cooling medium cools the electrolyte membrane / electrode structure 22, then moves through the cooling medium discharge communication hole 30b, is discharged to the manifold piping 48b connected to the end plate 20a, and is circulated for use.

  In this case, in the first embodiment, as shown in FIG. 3, the end separator 26a has an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, and a fuel gas supply communication. A current collector 52 is integrally formed facing at least the lower part of the hole 32a, the cooling medium discharge communication hole 30b, and the oxidant gas discharge communication hole 28b, and a plating treatment part 54 is formed on the surface of the current collector 52. Is provided.

  For this reason, for example, in the cooling medium supply communication hole 30a to which the cooling medium is supplied, the cooling medium directly contacts the current collector 52 of the end separator 26a, and the end separator 26a receives current through the cooling medium. Can be forced to flow. Therefore, in particular, it is possible to effectively suppress the occurrence of corrosion due to corrosion current flowing through the end separator 26a and the terminal plate 16a, and the occurrence of electric corrosion in the metal parts such as the end separator 26a and the terminal plate 16a.

  Specifically, the following description will be made with reference to the equivalent circuit shown in FIG. 7 in the cooling medium supply communication hole 30a shown in FIG.

The cooling medium flow path 42 formed between the power generation cells 12 communicates with the cooling medium supply communication hole 30a through an introduction part (bridge part) 42b. For this reason, as shown in FIG. 7, the liquid resistance R _A of the introduction portion 42 b exists between the power generation cells 12, while the liquid resistance R _B of the cooling medium supply communication hole 30 a exists for each power generation cell 12. is doing.

For example, the power generation cell 12 generates a voltage of 1 V, and 220 power generation cells 12 are stacked in series. The reaction resistance R _C of the current collector 52 is generated in the end separator 26a on the high potential side.

  Here, a configuration in which the current collector 52 is provided in the end separator 26a (first embodiment) and a configuration in which the current collector 52 is not provided in the end separator 26a (conventional example) were prepared. The relationship between the position of the power generation cell 12 and the corrosion current flowing through each cooling medium flow path 42 was detected using the first embodiment and the conventional example. The result is shown in FIG.

  As can be seen from FIG. 8, in the conventional example, a considerably high corrosion current flows in the cooling medium flow path 42 on the high potential side. On the other hand, in the first embodiment, the current collector 52 is provided on the high potential side, and a current corresponding to the above corrosion current flows through the current collector 52 forcibly. Corrosion current flowing through 42 was greatly reduced.

  As a result, in the first embodiment, the current collector 52 is provided in the end separator 26a on the high potential side, so that corrosion due to electrolytic corrosion occurs in metal parts (for example, the end separator 26a and the terminal plate 16a). The effect that it can prevent reliably is obtained. In addition, the current collector 52 is constituted by a metal surface portion that is partially peeled off from the second seal member 47 formed integrally with the end separator 26a and exposed to the outside. Therefore, the configuration of the current collector 52 is simplified, and the current collector 52 can be obtained economically.

  Furthermore, each current collector 52 is provided on the lower side of each communication hole, and pressure loss of the oxidant gas, fuel gas, and cooling medium flowing through each communication hole can be reduced well.

  FIG. 9 is a partially exploded perspective view of the fuel cell stack 60 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Similarly, in the third to ninth embodiments described below, detailed description thereof is omitted.

  The stack 62 constituting the fuel cell stack 60 includes an end separator 26a stacked on the high potential side terminal plate 16a and an end separator (first metal separator) 24a stacked on the low potential side terminal plate 16b. With. Each of the end separators 24a and 26a is integrally provided with the current collector 52 described above.

In the second embodiment configured as described above, the end separator 26a is disposed on the high potential side (cathode side) of the multilayer body 14, and is collected to reduce the corrosion current on the high potential side. An electric unit 52 is provided. On the other hand, the end separator 24a is disposed on the low potential side (anode side) of the laminate 14, and a current collector 52 is provided to avoid the influence of the low potential. For this reason, as shown in FIG. 10, the reaction resistance _RC of the current collector 52 is generated in the end separator 26a on the high potential side and the end separator 24a on the low potential side.

  Here, the conventional example mentioned above and the structure (this Example 2) which provided the current collection part 52 in the edge part separators 24a and 26a were prepared. The relationship between the position of the power generation cell 12 and the corrosion current flowing through each cooling medium flow path 42 was detected using the second embodiment and the conventional example. The result is shown in FIG.

  In the second embodiment, since the current collector 52 is provided in the end separator 24a, the anticorrosion current on the low potential side is greatly reduced as can be understood from FIG. Therefore, the current value can be approximated to 0 from the low potential side to the high potential side, and the effect that the corrosion current and the anticorrosion current can be satisfactorily reduced can be obtained.

  FIG. 12 is a partial cross-sectional side view of a fuel cell stack 70 according to the third embodiment of the present invention.

  The stack 72 constituting the fuel cell stack 70 includes an end separator 26b stacked on the high potential side terminal plate 16a, and an end separator (not shown) on the low potential side as necessary.

  In the end separator 26b, the second seal member 47 is partially peeled to expose the metal surface portion, and then the current collecting member 74 is joined to the metal surface portion by spot welding or the like. The current collecting member 74 is formed of, for example, a copper material subjected to gold plating, platinum, carbon, or iridium as a rust prevention structure.

  FIG. 13 is a partial cross-sectional side view of a fuel cell stack 80 according to the fourth embodiment of the present invention.

  The stacked body 82 constituting the fuel cell stack 80 includes an end separator 26c stacked on the terminal plate 16a on the high potential side, and an end separator (not shown) on the low potential side as necessary.

  A current collecting member 84 is joined to the end separator 26c by spot welding or the like, avoiding the second seal member 47. The current collecting member 84 is configured in the same manner as the current collecting member 74 described above. The same applies to each current collecting member used in the fifth to eighth embodiments described below.

  FIG. 14 is a perspective explanatory view of an end separator 26d constituting a fuel cell stack according to the fifth embodiment of the present invention.

  The end separator 26d includes an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas discharge communication hole 28b. The current collecting member 90 is provided individually or integrally so as to face at least the lower part of the battery. A plurality of holes 92 are formed in the current collecting member 90 and are configured to relieve fluid resistance (pressure loss).

  FIG. 15 is a perspective explanatory view of an end separator 26e constituting a fuel cell stack according to the sixth embodiment of the present invention.

  The end separator 26e includes an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas discharge communication hole 28b. Fin members (current collectors) 100 are provided individually or integrally so as to face at least the lower part of the plate. The fin member 100 includes a plurality of plate members 102 extending in the arrow B direction and a plurality of plate members 104 extending in the arrow C direction.

  FIG. 16 is a perspective explanatory view of an end separator 26f constituting a fuel cell stack according to the seventh embodiment of the present invention.

  On one surface of the end separator 26f, an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas are provided. A mesh member (current collector) 110 is disposed corresponding to at least the lower part of the discharge communication hole 28b. The mesh member 110 may be provided over the entire opening area of each communication hole, or may be provided only on the lower side of the communication hole.

  FIG. 17 is a perspective explanatory view of an end separator 26g constituting the fuel cell stack according to the eighth embodiment of the present invention.

  On one surface of the end separator 26g, an oxidant gas supply communication hole 28a, a cooling medium supply communication hole 30a, a fuel gas discharge communication hole 32b, a fuel gas supply communication hole 32a, a cooling medium discharge communication hole 30b, and an oxidant gas are provided. A plurality of groove portions 120 are formed extending in the direction of arrow B for each discharge communication hole 28b. Each groove 120 accommodates a bar (current collector) 122, and the circumferential surface of the bar 122 is disposed on substantially the same plane as one surface of the end separator 26g.

  In said 2nd-8th embodiment, each current collection part can be directly contacted with produced | generated water and a cooling medium, and can perform a current collection process, and can prevent the corrosion by the electric corrosion of a metal component. For example, the same effects as those of the first embodiment can be obtained.

  FIG. 18 is a partial sectional side view of a fuel cell stack 130 according to the ninth embodiment of the present invention.

  In the laminated body 132 constituting the fuel cell stack 130, the metal surface on the side of the channel groove 40 a constituting the oxidant gas channel 40 is added to all (or a predetermined number) of the first metal separators 24 constituting each power generation cell 12. A current collecting portion 134 is provided from the portion to a part of the first seal member 45. The current collector 134 is composed of a conductive film, a conductive resin, a conductive adhesive, or a conductive paint. For example, an anisotropic conductive film is used as the conductive film. Specifically, as the conductive adhesive, for example, an adhesive mainly containing CF silane is used containing carbon black, and as the conductive film, for example, polypropylene containing carbon black is used. As the conductive resin, for example, a phenol resin containing carbon black is used.

  In the ninth embodiment configured as described above, the current collector 134 is provided in all (or a predetermined number) of the first metal separators 24 constituting each power generation cell 12. Therefore, in the oxidant gas flow path 40, the effect that the generated water becomes a conductor and partial electric corrosion due to the flow of current can be surely prevented is obtained.

  For example, when a relatively expensive current collecting member such as platinum or silver is used as the current collecting unit 134, the current collecting member is provided only on the first metal separator 24 at least on the highest potential side of the stacked body 132. May be provided. For this reason, the current collection part 134 can be comprised economically.

1 is a partially exploded perspective view of a fuel cell stack according to a first embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a perspective explanatory view in the state where the end separator which constitutes the fuel cell stack was separated. It is a partially expanded perspective explanatory view of the end separator. It is the VV sectional view taken on the line of the said edge part separator shown in FIG. It is sectional explanatory drawing along a cooling-medium supply communication hole. FIG. 6 is an equivalent circuit diagram of FIG. 5. It is a related figure of the number of laminations of a power generation cell, and a corrosion current. FIG. 4 is a partially exploded perspective view of a fuel cell stack according to a second embodiment of the present invention. FIG. 3 is an equivalent circuit diagram in a cooling medium supply communication hole constituting the fuel cell stack. It is a related figure of the number of lamination | stacking of a power generation cell, and a corrosion current and anticorrosion current. It is a partial cross section explanatory view of the fuel cell stack concerning a 3rd embodiment of the present invention. It is a partial cross section explanatory view of the fuel cell stack concerning a 4th embodiment of the present invention. It is a perspective explanatory view of an end separator which constitutes a fuel cell stack concerning a 5th embodiment of the present invention. It is a perspective explanatory view of an end separator which constitutes a fuel cell stack concerning a 6th embodiment of the present invention. It is a perspective explanatory view of an end separator which constitutes a fuel cell stack concerning a 7th embodiment of the present invention. It is a perspective explanatory view of the end separator which constitutes the fuel cell stack concerning an 8th embodiment of the invention. It is a partial cross section side view of the fuel cell stack concerning a 9th embodiment of the present invention. 2 is a partial cross-sectional explanatory view of a fuel cell stack of Patent Document 1. FIG.

Explanation of symbols

10, 60, 70, 80, 130 ... Fuel cell stack 12 ... Power generation cells 14, 62, 72, 82, 132 ... Laminated bodies 16a, 16b ... Terminal plates 18a, 18b ... Insulating plates 20a, 20b ... End plates 22 ... Electrolytes Membrane / electrode structures 24, 26 ... metal separators 24a, 26a to 26g ... end separator 28a ... oxidant gas supply communication hole 28b ... oxidant gas discharge communication hole 30a ... cooling medium supply communication hole 30b ... cooling medium discharge communication hole 32a ... Fuel gas supply communication hole 32b ... Fuel gas discharge communication hole 34 ... Solid polymer electrolyte membrane 36 ... Anode side electrode 38 ... Cathode side electrode 40 ... Oxidant gas flow path 42 ... Coolant flow path 44 ... Fuel gas flow path 52, 134 ... current collecting portion 54 ... plating processing portions 74, 84, 90 ... current collecting member 100 ... fin member 110 ... mesh portion 122 ... bars

Claims (7)

An electrolyte / electrode structure having a pair of electrodes disposed on both sides of the electrolyte, and alternately stacking the electrolyte / electrode structure and the separator, and penetrating in the stacking direction to at least a cooling medium or reaction gas. A fuel cell stack in which a fluid communication hole for flowing any fluid is formed, while a fluid flow path for flowing the fluid along the electrode surface is formed,
The separator is formed of a metal plate, and provided with a seal member that covers an inner wall of the fluid communication hole of the metal plate and prevents the fluid from contacting the metal plate .
A space between the fluid communication hole and the fluid flow path is covered with a seal member,
At least the highest potential side of the separator, in contact with the cooling medium or water produced by flowing the cooling medium or current through the produced water, the fluid flow path of the most high-potential-side separator A fuel cell stack comprising a current collector for reducing a flowing corrosion current . The fuel cell stack according to claim 1, wherein the current collector is characterized in that said bonded to the metal surface of the metal plate is a metal member which projects over the front Symbol seal member to the fluid passage And fuel cell stack.   2. The fuel cell stack according to claim 1, wherein the current collector is formed of a metal surface portion desired for the fluid communication hole by notching a part of the seal member. 3.   2. The fuel cell stack according to claim 1, wherein the current collector is formed of a metal member that is joined to a metal surface portion of the metal plate and protrudes into the fluid communication hole.   The fuel cell stack according to any one of claims 1 to 4, wherein the current collector has a rust prevention structure.   2. The fuel cell stack according to claim 1, wherein the current collector is connected to a metal surface portion of the metal plate and covers a part of the seal member.   7. The fuel cell stack according to claim 6, wherein the current collector is made of a conductive film, a conductive adhesive, or a conductive paint.

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