JP5372627B2 - Fuel cell - Google Patents

Description

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a metal separator are stacked, and a reaction gas is passed along the electrode surface between the electrolyte / electrode structure and the metal separator. The present invention relates to a fuel cell in which a reaction gas flow path to be supplied is formed and a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow path.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is provided by a pair of separators. The unit cell is sandwiched. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  In the above fuel cell, a fuel gas channel (reactive gas channel) for flowing fuel gas is provided in the surface of one separator so as to face the anode side electrode, and in the surface of the other separator, An oxidant gas flow path (reaction gas flow path) for flowing an oxidant gas is provided facing the cathode side electrode. Further, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  Furthermore, in this type of fuel cell, a fuel gas inlet communication hole (reactive gas communication hole) and a fuel gas outlet communication hole (reactive gas communication hole) for flowing fuel gas through the unit cell in the stacking direction, Oxidant gas inlet communication hole (reaction gas communication hole) and oxidant gas outlet communication hole (reaction gas communication hole) for flowing the oxidant gas, and cooling medium inlet communication hole and cooling medium outlet communication hole for flowing the cooling medium In many cases, a so-called internal manifold type fuel cell is provided.

  At that time, the reaction gas channel and the reaction gas communication hole communicate with each other through a connection channel having parallel grooves or the like in order to allow the reaction gas to flow smoothly and evenly. However, when the separator and the electrolyte / electrode structure are clamped and fixed with a seal member interposed therebetween, the seal member enters the connecting flow path, and the desired sealing performance cannot be maintained. In addition, there is a problem that the reaction gas does not flow well.

  Therefore, in the polymer electrolyte fuel cell stack disclosed in Patent Document 1, a meandering reaction gas, for example, an oxidant gas flow path 2 is formed in the plane of the separator 1 as shown in FIG. . The oxidant gas flow channel 2 communicates with an oxidant gas supply through hole 3 and an oxidant gas discharge through hole 4 that penetrate the peripheral edge of the separator 1 in the stacking direction. A packing 5 is disposed in the separator 1, and the through holes 3, 4 and the oxidant gas flow path 2 are communicated with each other in the plane of the separator 1, and other through holes are sealed from these.

  In the connection flow paths 6a and 6b that connect the through holes 3 and 4 and the oxidant gas flow path 2, a SUS plate 7 that is a seal member is disposed so as to cover the connection flow paths 6a and 6b. The SUS plate 7 is formed in a rectangular shape, and ears 7a and 7b are provided at two locations, respectively, and the ears 7a and 7b are fitted to a step 8 formed on the separator 1.

  Thus, in Patent Document 1, since the SUS plate 7 covers the connection flow paths 6a and 6b, the polymer film (not shown) and the packing 5 do not fall into the oxidant gas flow path 2, The desired sealing performance can be ensured, and an increase in the pressure loss of the reaction gas can be prevented.

JP 2001-266911 A

  In the above-mentioned Patent Document 1, the connection flow paths 6a and 6b are usually configured by a plurality of grooves. For this reason, in particular, when a metal separator is used, there is a problem that the line pressure of the seal line crossing the connecting flow paths 6a and 6b is lost when the interval between the grooves is enlarged.

  The present invention solves this type of problem, and provides a fuel cell capable of preventing a load drop as much as possible and ensuring a desired sealing function with an economical and simple configuration. With the goal.

  In the present invention, an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a metal separator are stacked, and a reaction gas is passed along the electrode surface between the electrolyte / electrode structure and the metal separator. The present invention relates to a fuel cell in which a reaction gas flow path to be supplied is formed and a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow path.

On one surface of the metal separator, projecting a plurality of concave portions for communicating the reactant gas passage and the reactant gas flow field is by being pressed formed is opposite shape of the groove portion on the other surface of the metal separator with the shape portion is formed, the opposite to the other surface of the metallic plates, on one surface of at least one surface of the adjacent metal separators, or end member, positioned between front Kitotsu shaped portion A receiving member is provided.

  The end member is preferably an insulating plate or a terminal plate.

  In the present invention, the metal separator is press-formed with a plurality of concave grooves communicating the reactive gas communication hole and the reactive gas flow path, and is received between the convex shaped parts opposite to the concave groove. A member is provided. For this reason, even if the interval between the convex portions is enlarged, it does not depend on the rigidity of the metal separator itself, and it is possible to reduce the line pressure of the seal line through the receiving member while reducing the thickness of the metal separator. Can be suppressed.

  As a result, it is possible to prevent a load drop as much as possible with an economical and simple configuration and to secure a desired sealing function.

1 is a perspective explanatory view of a fuel cell stack in which fuel cells according to a first embodiment of the present invention are stacked. FIG. It is a principal part disassembled perspective explanatory drawing of the said fuel cell. FIG. 3 is a cross sectional view of the fuel cell stack taken along line III-III in FIG. 2. It is front explanatory drawing of the 1st metal separator which comprises the said fuel cell. FIG. 5 is a cross-sectional explanatory view of the fuel cell stack taken along line VV in FIG. 2. It is front explanatory drawing of the 2nd metal separator which comprises the said fuel cell. It is explanatory drawing when a convex part is formed in a terminal plate. It is a principal part disassembled perspective explanatory drawing of the fuel cell which concerns on the 2nd Embodiment of this invention. It is front view explanatory drawing of the separator which comprises the fuel cell stack which concerns on patent document 1. FIG.

  As shown in FIG. 1, the fuel cell 10 according to the first embodiment of the present invention is stacked in the direction of arrow A to constitute a fuel cell stack 12. Terminal plates 14a and 14b, insulating plates 16a and 16b, and end plates 18a and 18b are disposed at both ends of the fuel cell 10 in the stacking direction.

  The terminal plates 14a and 14b are accommodated in recesses (not shown) formed in the central portions of the insulating plates 16a and 16b, and the power extraction terminals 20a and 20b are located outside the stacking direction from the centers of the terminal plates 14a and 14b. Protrudes towards. The end plates 18a and 18b are fastened in the stacking direction by tie rods (not shown). Instead, the fuel cell 10 is accommodated in a casing (not shown) having the end plates 18a and 18b as end plates. Also good.

  As shown in FIGS. 2 and 3, in the fuel cell 10, an electrolyte membrane / electrode structure (electrolyte / electrode structure) 24 is sandwiched between a first metal separator 26 and a second metal separator 28. The first metal separator 26 and the second metal separator 28 are constituted by, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, or a vertically long metal plate obtained by performing a surface treatment for anticorrosion on the metal surface. The first metal separator 26 and the second metal separator 28 have a rectangular planar shape, and are formed into a concavo-convex shape by pressing a metal thin plate into a wave shape.

  One end edge of the fuel cell 10 in the direction of arrow B (the horizontal direction in FIG. 2) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidizes for supplying an oxidant gas, for example, an oxygen-containing gas. An agent gas inlet communication hole 30a, a cooling medium outlet communication hole 32b for discharging a cooling medium, and a fuel gas outlet communication hole 34b for discharging a fuel gas, for example, a hydrogen-containing gas, are provided in the direction of arrow C (vertical direction). Are provided in an array.

  The other end edge of the fuel cell 10 in the direction of arrow B communicates with each other in the direction of arrow A, a fuel gas inlet communication hole 34a for supplying fuel gas, and a cooling medium inlet communication hole for supplying a cooling medium. 32a and oxidant gas outlet communication holes 30b for discharging the oxidant gas are arranged in the direction of arrow C.

  As shown in FIGS. 2 and 4, on the surface 26a of the first metal separator 26 on the electrolyte membrane / electrode structure 24 side, for example, an oxidant gas flow path (reactive gas) extending linearly in the arrow B direction. A flow path) 36 is provided. The oxidant gas flow path 36 includes a plurality of grooves provided by forming the first metal separator 26 into a wave shape, and the oxidant gas flow path 36 is provided on the opposite surface 26 b of the first metal separator 26. A part of the cooling medium flow path 38 having a back surface shape is formed.

  The oxidant gas flow path 36 communicates with the oxidant gas inlet communication hole 30a and the oxidant gas outlet communication hole 30b via the connection flow paths 40a and 40b. The connection flow paths 40a and 40b each have a plurality of concave grooves 42a and 42b arranged in the direction of arrow C (see FIGS. 3 to 5). The recessed groove portions 42 a and 42 b are press-molded in the first metal separator 26.

  2 and 6, the surface 28a of the second metal separator 28 on the electrolyte membrane / electrode structure 24 side communicates with the fuel gas inlet communication hole 34a and the fuel gas outlet communication hole 34b, and the arrow B A fuel gas channel (reactive gas channel) 44 extending in the direction is formed.

  The fuel gas channel 44 includes a plurality of grooves provided by forming the second metal separator 28 into a wave shape, and the fuel gas channel 44, the fuel gas inlet communication hole 34a, and the fuel gas outlet communication hole 34b, Communicate with each other via the connecting flow paths 46a and 46b. The connection flow paths 46a and 46b have a plurality of concave grooves 48a and 48b arranged in the direction of arrow C, respectively. The recessed groove portions 48 a and 48 b are press-molded in the second metal separator 28.

  As shown in FIG. 2, a part of the cooling medium flow path 38 communicating with the cooling medium inlet communication hole 32a and the cooling medium outlet communication hole 32b is formed on the surface 28b opposite to the surface 28a of the second metal separator 28. It is formed.

  The first seal member 50 is integrated with the surfaces 26a and 26b of the first metal separator 26 by baking or injection molding around the outer peripheral end of the first metal separator 26. The second seal member 52 is integrated with the surfaces 28a and 28b of the second metal separator 28 around the outer peripheral end of the second metal separator 28 by baking or injection molding.

  The first seal member 50 and the second seal member 52 are, for example, EPDM, NBR, fluororubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber, or a cushioning material. Or use packing material.

  As shown in FIG. 4, the surface 26 b of the first metal separator 26 protrudes toward the cooling medium flow path 38, and is between the convex portions that are opposite to the concave grooves 48 a and 48 b provided in the second metal separator 28. The receiving members 54a and 54b are provided at the positions. For example, the receiving members 54 a and 54 b are integrally formed with the first seal member 50, but may be configured separately from the first seal member 50. The same applies hereinafter.

  The receiving member 56a is located on the surface 28b of the second metal separator 28 and protrudes toward the cooling medium flow path 38 and is located between the convex portions that are opposite to the concave grooves 42a and 42b provided in the first metal separator 26. , 56b (see FIGS. 2, 3 and 5). The receiving members 56a and 56b are integrally formed with the first seal member 50, for example.

  As shown in FIG. 5, the insulating plate 16b adjacent to the first metal separator 26 arranged at the extreme end in the stacking direction is positioned between the convex portions which are opposite to the concave groove portions 42a and 42b. A member 58 is provided. Similarly, although not shown, the insulating plate 16a adjacent to the second metal separator 28 disposed at the extreme end in the stacking direction is positioned between the convex portions that are opposite to the concave groove portions 48a and 48b. A member is provided.

  2 and 3, the electrolyte membrane / electrode structure 24 includes, for example, a solid polymer electrolyte membrane 60 in which a perfluorosulfonic acid thin film is impregnated with water, and the solid polymer electrolyte membrane 60 interposed therebetween. An anode side electrode 62 and a cathode side electrode 64 are provided. The outer peripheral edge of the solid polymer electrolyte membrane 60 protrudes outward from the outer peripheral ends of the anode side electrode 62 and the cathode side electrode 64.

  The anode side electrode 62 and the cathode side electrode 64 include a gas diffusion layer made of carbon paper or the like, and an electrode catalyst layer in which porous carbon particles having a platinum alloy supported on the surface are uniformly applied to the surface of the gas diffusion layer. And have. The electrode catalyst layers are bonded to both surfaces of the solid polymer electrolyte membrane 60 so as to face each other with the solid polymer electrolyte membrane 60 interposed therebetween.

  The cathode-side electrode 64 includes projecting end portions 64a and 64b projecting toward the connection flow paths 40a and 40b (outward in the direction of arrow B) of the first metal separator 26 along the surface direction. The anode side electrode 62 has projecting end portions 62a and 62b projecting into the connection flow paths 46a and 46b of the second metal separator 28 along the surface direction.

  As shown in FIG. 1, the end plate 18a includes an oxidant gas inlet communication hole 30a, a cooling medium outlet communication hole 32b, and an oxidant gas inlet manifold 66a communicating with the fuel gas outlet communication hole 34b, a cooling medium outlet manifold 68b, and A fuel gas outlet manifold 70b, a fuel gas inlet communication hole 34a, a cooling medium inlet communication hole 32a, and a fuel gas inlet manifold 70a communicating with the oxidant gas outlet communication hole 30b; a cooling medium inlet manifold 68a and an oxidant gas outlet manifold 66b; Is provided.

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

  First, as shown in FIG. 1, a fuel gas such as a hydrogen-containing gas is supplied from the fuel gas inlet manifold 70a to the fuel gas inlet communication hole 34a, and from the oxidant gas inlet manifold 66a to the oxidant gas inlet communication hole 30a. An oxidant gas such as an oxygen-containing gas is supplied. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied from the cooling medium inlet manifold 68a to the cooling medium inlet communication hole 32a.

  Therefore, as shown in FIGS. 2 and 6, the fuel gas is introduced into the fuel gas flow path 44 of the second metal separator 28 from the fuel gas inlet communication hole 34a and moves in the direction of arrow B while It is supplied to the anode side electrode 62 constituting the electrode structure 24. On the other hand, the oxidant gas is introduced into the oxidant gas flow path 36 of the first metal separator 26 from the oxidant gas inlet communication hole 30a as shown in FIGS. It is supplied to the cathode side electrode 64 constituting the membrane / electrode structure 24.

  Therefore, in the electrolyte membrane / electrode structure 24, the oxidant gas supplied to the cathode side electrode 64 and the fuel gas supplied to the anode side electrode 62 are consumed by an electrochemical reaction in the electrode catalyst layer, and power generation is performed. Is done.

  Next, the fuel gas consumed by being supplied to the anode side electrode 62 is discharged in the direction of arrow A along the fuel gas outlet communication hole 34b. Similarly, the oxidant gas consumed by being supplied to the cathode side electrode 64 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 30b.

  The cooling medium supplied to the cooling medium inlet communication hole 32a is introduced into the cooling medium flow path 38 between the first and second metal separators 26 and 28 and then flows in the direction of arrow B. After cooling the electrolyte membrane / electrode structure 24, the cooling medium is discharged from the cooling medium outlet communication hole 32b.

  In this case, in the first embodiment, as shown in FIG. 5, the first metal separator 26 is provided with a plurality of concave groove portions 42 a constituting the connection flow path 40 a, and the second metal separator 28 has A receiving member 56a is provided that protrudes toward the cooling medium flow path 38 and is located between convex portions that are opposite to the concave groove portion 42a.

  For this reason, even if the interval between the concave groove portions 42a (the interval between the convex shaped portions) is enlarged, it does not depend on the rigidity of the first metal separator 26 itself, and the line pressure of the seal line is excellent through the receiving member 56a. Can be suppressed. Thereby, it is possible to obtain an effect of preventing a load drop as much as possible with an economical and simple configuration and securing a desired sealing function.

  In addition, the first metal separator 26 (and the second metal separator 28) can be thinned, and the fuel cell 10 can be easily reduced in size and weight.

  Furthermore, in 1st Embodiment, the receiving member 58 is provided in the insulating plate 16b located between the convex shape parts which are the opposite shapes of the concave groove parts 42a and 42b. Therefore, in particular, the first metal separator 26 disposed at the extreme end in the stacking direction can satisfactorily suppress the line pressure loss of the seal line.

  In the first embodiment, the receiving member 58 and the like are provided on the insulating plate 16b. Instead, for example, as shown in FIG. 7, the terminal plates 14a and 14b are provided with convex portions (receiving members). 72 may be provided. Although not shown, a dummy cell may be provided at the end in the stacking direction, and a receiving member may be provided on the dummy cell. The dummy cell is generally configured in the same manner as the fuel cell 10, and uses a plate member (non-power generation body) of the same thickness instead of the electrolyte membrane / electrode structure 24, and this plate member is connected to the first metal separator 26. What is necessary is just to comprise between 2nd metal separators 28 and to comprise. Furthermore, the receiving member may be provided on at least one of a metal separator, an insulating plate, a terminal plate, or a dummy cell.

  FIG. 8 is an exploded perspective view of a main part of a fuel cell 80 according to the second embodiment of the present invention. The same components as those of the fuel cell 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The fuel cell 80 includes a first metal separator 26, a first electrolyte membrane / electrode structure (electrolyte / electrode structure) 24a, an intermediate metal separator 82, a second electrolyte membrane / electrode structure 24b, and a second metal separator 28. . The intermediate metal separator 82 is provided with a fuel gas channel 84 on a surface 82a facing the first electrolyte membrane / electrode structure 24a, and an oxidant gas channel 86 on a surface 82b facing the second electrolyte membrane / electrode structure 24b. Is provided.

  In the second embodiment configured as described above, the first metal separator 26 and the second metal separator 28 are provided, and the same effect as in the first embodiment can be obtained.

DESCRIPTION OF SYMBOLS 10, 80 ... Fuel cell 12 ... Fuel cell stack 24, 24a, 24b ... Electrolyte membrane and electrode structure 26, 28 ... Metal separator 30a ... Oxidant gas inlet communication hole 30b ... Oxidant gas outlet communication hole 32a ... Cooling medium inlet Communication hole 32b ... Cooling medium outlet communication hole 34a ... Fuel gas inlet communication hole 34b ... Fuel gas outlet communication hole 36, 86 ... Oxidant gas flow path 38 ... Cooling medium flow path 40a, 40b, 46a, 46b ... Connection flow path 42a , 42b, 48a, 48b ... concave groove 44, 84 ... fuel gas flow path 50, 52 ... sealing members 54a, 54b, 56a, 56b, 58 ... receiving member 60 ... solid polymer electrolyte membrane 62 ... anode side electrode 64 ... cathode Side electrode 82 ... Intermediate metal separator

Claims (2)

A reaction gas in which a pair of electrodes is provided on both sides of an electrolyte and an electrode / electrode structure and a metal separator are stacked, and a reaction gas is supplied along the electrode surface between the electrolyte / electrode structure and the metal separator. A fuel cell having a reaction gas communication hole formed therein and having a reaction gas communication hole penetrating in the stacking direction and communicating with the reaction gas flow channel,
On one surface of the metal separator, the reaction gas passage and said reactant gas channel by a plurality of recessed grooves communicating is pressed formed, opposite shape of the groove portion on the other surface of the metal separator As a convex shape part is formed ,
The opposite to the other surface of the metal separator, at least one surface of the adjacent metal separators, or on one surface of the end member, that the receiving member is located is provided between front Kitotsu shaped portion A fuel cell.   2. The fuel cell according to claim 1, wherein the end member is an insulating plate or a terminal plate.

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