JP2014127295A - Fuel cell separator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent cracks from traversing a seal line even when the cracks occur in a resin member.SOLUTION: A fuel cell separator includes a resin member and a reinforcing member for reinforcing the resin member. The resin member has a seal line to seal a fluid used for a fuel cell and a crack guiding groove arranged in parallel with the seal line, on the surface of the opposite side from the reinforcing member.

Description

  The present invention relates to a fuel cell separator.

  A solid polymer electrolyte fuel cell separator is known (Patent Document 1). In this battery separator, a conductive resin layer mixed with a conductive filler is laminated on at least one surface of a metal substrate.

JP 2009-280355 A

  A crack may occur in the conductive resin layer (resin member). When the crack crosses the seal line of the conductive resin layer, there is a possibility that fluid such as a reaction gas or cooling water leaks along the crack.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

(1) According to one aspect of the present invention, a fuel cell separator is provided. The fuel cell separator includes a resin member and a reinforcing member that reinforces the resin member, and the resin member seals a fluid used in the fuel cell on a surface opposite to the reinforcing member. And a crack induction groove that runs parallel to the seal line. According to the fuel cell separator of this embodiment, even if the resin member is cracked, when the crack reaches the crack induction groove, the crack does not cross the seal line because the crack follows the crack induction groove. As a result, it is possible to suppress leakage along the cracks of the reaction gas and cooling water.

(2) In the fuel cell separator of the above aspect, two or more crack induction grooves may be provided across the seal line. According to the fuel cell separator of this embodiment, it is possible to suppress the leakage of the reaction gas and the cooling water regardless of whether the crack occurs from the inside or the outside of the seal line.

(3) In the fuel cell separator of the above aspect, the thickness of the resin member at the bottom of the crack induction groove may be smaller than the thickness of the resin member at the center of the seal line. According to the fuel cell separator of this embodiment, since the thickness of the resin member in the crack induction groove is thinner than the thickness of the resin member in the seal line, the crack is easily along the crack induction groove.

(4) In the fuel cell separator according to the above aspect, the thickness of the resin member at the bottom of the crack induction groove may be less than or equal to half the thickness of the resin member at the center of the seal line. According to the fuel cell separator of this embodiment, since the thickness of the resin member in the crack induction groove is less than half the thickness of the resin member in the seal line, the crack is likely to follow the crack induction groove.

(5) In the fuel cell separator of the above aspect, the resin member has a gasket holding groove for holding a gasket, and the seal line and the crack induction groove are formed in the gasket holding groove. May be. According to the fuel cell separator of this embodiment, it is possible to reliably hold the gasket and suppress the leakage of the reaction gas and the cooling water.

(6) In the fuel cell separator, a second crack induction groove may be provided on the outer edge side of the gasket holding groove. According to the fuel cell separator of this embodiment, even if a crack is generated from the outer edge side of the seal line, the crack can be caused to follow the second crack induction groove, so that the crack can reach the shoulder of the gasket holding groove. Therefore, it is possible to suppress leakage of the reaction gas and the cooling water.

(7) In the fuel cell separator, the thickness of the resin member at the bottom of the second crack induction groove may be smaller than the thickness of the resin member at the center of the seal line. According to the fuel cell separator of this embodiment, the crack does not cross the seal line because it follows the second crack induction groove. As a result, it is possible to suppress leakage along the cracks of the reaction gas and cooling water.

  The present invention can be realized in various forms, for example, in the form of a fuel cell separator, a fuel cell, a fuel cell separator seal structure, and the like.

It is explanatory drawing which shows the fuel cell concerning 1st Embodiment. It is a perspective view of the separator for anode side fuel cells. It is explanatory drawing which shows a part of separator for anode side fuel cells concerning the 1st Embodiment of this invention, and the effect of this embodiment. It is explanatory drawing which expands and shows a gasket holding groove. It is sectional drawing which shows a part of separator for fuel cells concerning the 2nd Embodiment of this invention. It is explanatory drawing which shows the form which joins the separator for anode side fuel cells, and the resin frame using the structure of 1st Embodiment. It is explanatory drawing which shows the form which joins the separator for anode side fuel cells, and the resin frame using the structure of 2nd Embodiment. It is explanatory drawing which shows the modification of 2nd Embodiment.

First embodiment:
FIG. 1 is an explanatory view showing a fuel cell according to the first embodiment. The fuel cell 10 includes a plurality of single cells 20 and end members 30. A plurality of unit cells 20 are stacked to form a fuel cell stack 25. The end members 30 are disposed at both ends of the fuel cell stack 25. The electric power from the fuel cell stack 25 is taken out from the end member 30. The single cell 20 includes an anode side fuel cell separator 100, a cathode side fuel cell separator 500, and a resin frame 400. The resin frame 400 holds the membrane electrode assembly. The anode side fuel cell separator 100 and the cathode side fuel cell separator 500 sandwich the resin frame 400. The anode-side fuel cell separator 100 is in contact with the cathode-side fuel cell separator 500 of the adjacent single cell 20.

  FIG. 2 is a perspective view of the anode-side fuel cell separator 100. In FIG. 2, the upper side that is visible is the side that contacts the cathode side fuel cell separator 500 of the anode side fuel cell separator 100, and the lower side that is hidden is the resin frame 400 of the anode side fuel cell separator 100. The side that touches. The anode side fuel cell separator 100 has a rectangular shape. A total of six opening holes 101 to 106 are formed on opposing sides of the anode-side fuel cell separator 100. The opening holes 101 to 106 are respectively supplied with fuel gas (opening hole 101) and discharge (opening hole 102), supplied with oxidizing gas (opening hole 103) and discharge (opening hole 104), and supplied with refrigerant (opening hole 105). ) And discharge (opening hole 106). On the cathode side fuel cell separator 500 side visible in FIG. 2, the gasket holding groove 112 is formed at a position surrounding the outer edge portion of the anode side fuel cell separator 100 and the opening holes 101 to 104. On the side of the resin frame 400 hidden in FIG. 2, the gasket holding groove (gasket holding groove 122) is formed at a position surrounding the outer edge portion of the anode-side fuel cell separator 100 and the opening holes 103 to 106. The refrigerant flows between the anode side fuel cell separator 100 and the cathode side fuel cell separator 500, and the fuel gas flows between the anode side fuel cell separator 100 and the resin frame 400.

  Although not shown, the cathode side fuel cell separator 500 has the same configuration. The gasket holding groove (gasket holding groove 512) on the anode side fuel cell separator 100 side of the cathode side fuel cell separator 500 is positioned so as to surround the outer edge of the cathode side fuel cell separator 500 and the opening holes 501 to 504, respectively. Is formed. However, in the portion where the gasket holding groove 112 of the anode side fuel cell separator 100 and the gasket holding groove (gasket holding groove 512) of the cathode side fuel cell separator 500 overlap, the gasket holding groove is for the anode side fuel cell. It may be formed on both the separator 100 and the cathode side fuel cell separator 500, or may be formed on either one.

  FIG. 3 is an explanatory diagram showing a part of the anode-side fuel cell separator according to the first embodiment of the present invention and the effect of this embodiment. In FIG. 3, a joint portion between the anode-side fuel cell separator 100 and the cathode-side fuel cell separator 500 will be described. 3A is a cross-sectional view, and FIG. 3B is a plan view. 3A and 3B, the left side is the inside of the single cell 20 of the fuel cell 10, and the right side is the outer edge side of the single cell 20. In the plan view, a part of the present embodiment and a part of the comparative example are shown in the same drawing so that the comparison between the present embodiment and the comparative example is easy.

  The anode-side fuel cell separator 100 according to the first embodiment includes resin members 110 and 120 and a reinforcing member 130. The reinforcing member 130 is sandwiched between the resin member 110 and the resin member 120. The resin member 110 is on the cathode side fuel cell separator 500 side, and the resin member 120 is on the resin frame 400 side. This anode-side fuel cell separator 100 can be formed by laminating a resin-carbon composite material on both sides of the reinforcing member 130 and press molding. In the present embodiment, a thermoplastic resin such as polyethylene or polypropylene can be used as the resin. In addition, the material of the resin raised here is an example. It is also possible to use a resin other than the thermoplastic resin, for example, a thermosetting resin. Moreover, in order to give the resin members 110 and 120 conductivity, the resin contains carbon. As the reinforcing member 130, a metal such as titanium or stainless steel can be used. The material raised here is an example, and other reinforcing members 130 may be made of a metal other than the metal described here, a resin sheet, or the like.

  The resin member 110 includes a gasket holding groove 112. The gasket holding groove 112 is a recess provided on the surface of the resin member 110 in order to hold the gasket 200. The flat portions on both sides of the gasket holding groove 112 are called “gasket shoulders 114”. Two first crack induction grooves 116 that run in parallel with the gasket holding groove 112 are formed along the gasket holding groove 112 at the bottom of the gasket holding groove 112. A seal line 117 is formed between the two first crack induction grooves 116. The gasket 200 is in contact with the cathode side fuel cell separator 500 at the seal line 117. The first crack induction groove 116 only needs to run in parallel with the seal line 117, but is preferably parallel to the seal line 117. In the present embodiment, the second crack induction groove 118 is formed on the outer edge side of the gasket shoulder 114. The second crack induction groove 118 may be provided inside the single cell 20 with respect to the first crack induction groove 116.

  The thickness of the resin member 110 is as follows. The thickness of the resin member 110 in the seal line 117 is h1, the thickness of the bottom of the first crack induction groove 116 is h2, the thickness of the gasket shoulder 114 is h3, and the second crack induction groove 118. The thickness at the bottom of is h4. Here, the thickness h <b> 2 in the first crack induction groove 116 is preferably smaller than the thickness h <b> 1 of the resin member 110 in the seal line 117 and is ½ or less of h <b> 1. The thickness h4 in the second crack induction groove 118 is preferably thinner than the thickness h1 of the resin member 110 in the seal line 117.

  The gasket 200 is fitted in the gasket holding groove 112 and suppresses leakage of reaction gas and refrigerant from the gap between the anode-side fuel cell separator 100 and the resin frame 400. The gasket 200 is made of rubber, for example. In FIG. 1A, a gasket having a convex cross section is used. However, for example, an elastic member having a circular cross section can be used as the gasket 200.

  As in the anode-side fuel cell separator 100, the cathode-side fuel cell separator 500 sandwiches the reinforcing member 530 between the resin members 510 and 520. The resin member 510 on the anode fuel cell separator 100 side includes a first crack induction groove 516. The resin member 510 illustrated in FIG. 3A is not provided with a gasket groove, but may be provided with a gasket groove. When the above-described elastic member having a circular cross section is used as the gasket 200, it is preferable to provide a gasket groove.

  Hereinafter, the case where the resin member 110 is cracked will be described. It is assumed that a crack 302 has occurred inside the seal line 117 of the resin member 110 (on the left side of FIGS. The crack 302 may spread left and right and up and down. When the crack 302 spreads in the outer edge direction (right direction) and reaches the first crack induction groove 116, the crack 302 is guided along the first crack induction groove 116 and does not cross the seal line 117. As a result, even if the reaction gas or the refrigerant flows along the crack 302, the seal line 117 is not exceeded. As a result, it is possible to suppress leakage of the reaction gas and the refrigerant to the outside of the fuel cell 10.

  The same applies when a crack 304 occurs on the outer edge side of the seal line 117 of the resin member 110. When the crack 304 reaches the first crack guide groove 116, the crack 304 is guided along the first crack guide groove 116 and does not cross the seal line 117. Since the crack 304 does not extend inward from the seal line 117, the reaction gas and the refrigerant do not reach the crack 304, and the leakage of the reaction gas and the refrigerant to the outside of the fuel cell 10 can be suppressed.

  The same applies when a crack 306 is formed on the outer edge side of the second crack induction groove 118 of the resin member 110. When the crack 306 reaches the second crack induction groove 118, the crack 306 is guided along the second crack induction groove 118 and does not extend toward the seal line 117. Since the crack 306 does not extend inward from the seal line 117, the reaction gas and the refrigerant do not reach the crack 306, and the leakage of the reaction gas and the refrigerant to the outside of the fuel cell 10 can be suppressed. Further, the extension of the crack 306 to the gasket shoulder 114 can be suppressed. The second crack induction groove 118 may not be provided.

  Next, a comparative example will be described. The resin member 110 of the comparative example has neither the first crack induction groove 116 nor the second crack induction groove 118. When the crack 308 occurs, the crack 308 may cross the seal line when the crack 308 extends, regardless of whether the crack 308 is generated on the inner side or the outer edge side of the seal line 117. In such a case, the reaction gas and the refrigerant will cross the seal line 117 along the crack 308. As a result, leakage of the reaction gas and refrigerant to the outside of the fuel cell 10 occurs.

  FIG. 4 is an explanatory view showing an enlarged gasket holding groove. The anode-side fuel cell separator 100 was formed by laminating a 0.3 mm resin-carbon composite material on both sides of a 0.1 mm titanium plate and then press-molding it. At the time of press molding, the refrigerant flow path and the gasket holding groove 112 were simultaneously formed in the resin member 110, and the reactive gas flow path and the gasket holding groove 122 were formed in the resin member 120. Since the general configuration of the gasket holding groove 112 has already been described in the description of FIG. 3, values of width and thickness will be described here. In this embodiment, the width of the gasket holding groove 112 is 3 mm, and the width of the seal line 117 is 2 mm. The thickness h1 of the resin member 110 in the seal line 117 is 0.1 mm, the thickness h2 of the resin member 110 in the first crack induction groove 116 is 0.05 mm, and the thickness h3 of the resin member 110 in the gasket shoulder 114 is 0.4 mm.

  As described above, according to the first embodiment, the resin member 110 includes the first crack guide groove 116 formed in parallel with the seal line along the seal line 117. Regardless of the crack that has occurred, when the crack extends and reaches the first crack induction groove 116, the crack is induced along the first crack induction groove 116, and the crack does not cross the seal line. As a result, it is possible to suppress leakage of the reaction gas and the refrigerant to the outside of the fuel cell 10 through the crack.

  According to this embodiment, since the first crack induction groove 116 is provided with the seal line 117 interposed therebetween, the fuel cell through the crack regardless of whether the crack occurs from the inside or the outside of the seal line 117. It becomes possible to suppress leakage of reaction gas and refrigerant to the outside. The first crack induction groove 116 may be provided only in one of the seal lines 117. It is possible to suppress crossing the seal line with respect to a crack generated from at least the side where the first crack induction groove 116 is provided. One first crack induction groove 116 may be provided immediately below the center of the seal line 117. When the resin member 110 has one first crack induction groove 116 immediately below the center of the seal line 117, the crack is generated regardless of whether the crack is generated from the inside or the outside of the seal line 117. Guided along the groove 116. As a result, the crack does not cross the seal line 117 on the side opposite the cracked side. as a result. It becomes possible to suppress the leakage of the reaction gas and the refrigerant to the outside of the fuel cell 10 through the crack. However, when the crack has progressed from both sides, the cracks on both sides may communicate with each other via the first crack guide groove 116 and the reaction gas and the refrigerant may leak. Therefore, it is preferable that the resin member 110 includes two or more first crack induction grooves 116 formed with the seal line 117 interposed therebetween.

  Further, according to the present embodiment, the thickness h2 of the resin member 110 at the bottom of the first crack induction groove 116 is thinner than the thickness h1 of the resin member 110 in the seal line 117, so the crack is the first crack. When reaching the guide groove 116, it is possible to induce a crack along the first crack guide groove 116. The thickness h1 is preferably less than or equal to half the thickness h2.

  Furthermore, according to the present embodiment, the seal line 117 and the first crack induction groove 116 are formed in the gasket holding groove 112, so that the gasket 200 can be reliably held by the gasket holding groove 112. Further, the seal line 117 and the first crack induction groove 116 can suppress the leakage of the reaction gas and the cooling water from the fuel cell 10.

  Further, according to the present embodiment, since the resin member 110 includes the second crack induction groove 118 on the outer edge side of the gasket holding groove 112, the crack 306 generated outside the second crack induction groove 118 is generated. It is possible to suppress extension to the gasket shoulder 114 and the seal line. The thickness h4 of the resin member 110 in the second crack induction groove 118 is preferably thinner than the thickness h1 of the resin member 110 in the seal line 117.

Second embodiment:
FIG. 5 is a cross-sectional view showing a part of a fuel cell separator according to a second embodiment of the present invention. In FIG. 5, the case where the anode side fuel cell separator 100 and the cathode side fuel cell separator 500 are bonded together will be described as an example. In the first embodiment described above, the resin member 110 has the gasket holding groove 112 and the gasket 200 is fitted into the gasket holding groove 112. On the other hand, in 2nd Embodiment, the resin member 120 is provided with the convex part 125 for sealing instead of the gasket holding groove. The resin member 120 is bonded to the cathode-side fuel cell separator 500 by providing an adhesive 210 on the top of the sealing convex portion 125. Further, instead of the adhesive 210, a sheet such as rubber may be used. Note that the adhesive 210 may be omitted.

  In the second embodiment, the first crack guiding groove 126 is formed on both sides of the sealing convex portion 125 so as to run parallel to the sealing convex portion 125. The thickness h5 of the resin member 120 at the bottom of the first crack induction groove 126 is thinner than the thickness h6 of the resin member 120 at the sealing convex portion 125. Even in the second embodiment, as in the first embodiment, even if a crack occurs on the inner side or the outer edge side of the sealing convex portion 125, the crack is guided along the first crack guide groove 126. Therefore, the crack does not cross the sealing projection 125. In addition, in FIG. 5, although the 2nd crack induction groove (128) is not illustrated, the structure provided with the 2nd crack induction groove 128 may be sufficient.

  According to the second embodiment, since the first crack guiding groove 126 is formed so as to run in parallel with the sealing convex portion 125, the crack is generated either on the inner side of the sealing convex portion 125 or on the outer edge side. Even if it occurs, the crack is guided along the first crack guide groove 126, so that the crack does not cross the sealing projection 125. As a result, it becomes possible to suppress leakage of the reaction gas and cooling water from the fuel cell 10. In the second embodiment, the sealing convex portion 125 is described as being provided on the resin member 110 of the anode fuel cell separator 100. However, the seal convex portion 125 is sealed on the resin member 510 of the cathode fuel cell separator 500. The structure by which the convex part for operation is provided may be sufficient.

  In the above description, the configurations of the first and second embodiments are used for joining the anode-side fuel cell separator 100 and the cathode-side fuel cell separator 500. The configurations of the first and second embodiments may be used for joining the anode-side fuel cell separator 100 and the resin frame 400, and may be used for joining the cathode-side fuel cell separator 500 and the resin frame 400. .

  FIG. 6 is an explanatory view showing a form in which the anode-side fuel cell separator 100 and the resin frame 400 are joined using the configuration of the first embodiment. 3 is replaced with the resin frame 400, and the resin member 120 on the resin frame 400 side has a gasket holding groove 122, a gasket shoulder 124, and first crack induction grooves 126 and 128. Since it is the same as FIG. 3 except that it is formed, the description is omitted.

  FIG. 7 is an explanatory view showing a form in which the anode-side fuel cell separator 100 and the resin frame 400 are joined using the configuration of the second embodiment. In the first and second embodiments described above, it has been described that the resin member 110 has a thickness in the first crack guide groove 116, but the thickness of the resin member is used instead of the first crack guide groove 116. The difference is that a crack-inducing groove 119 having a value of 0 is used. In this way, the crack induction groove 119 having a bottom thickness of zero may be used. In addition, since the anode side fuel cell separator 100 is provided with the reinforcing member 130, even if the resin member 110 has a zero thickness portion, it is not separated at the zero thickness portion. In the above description, the anode-side fuel cell separator 100 and the resin frame 400 have been described as examples. However, the same applies to the cathode-side fuel cell separator 500 and the resin frame 400.

Variations:
FIG. 8 is an explanatory diagram showing a modification of the second embodiment. In the second embodiment described above, the size of the reinforcing member 130 has not been specifically described. As shown in FIG. 5, the reinforcing member 130 may be sandwiched only around the seal line 117. The same applies to the first embodiment shown in FIG. Stress is applied in the vicinity of the seal line 117 as compared with other places. This stress may cause cracks. In this modification, it is possible to suppress the occurrence of cracks by providing the reinforcing member 130 at a place where stress is applied. A similar configuration can be employed in the first embodiment.

  The embodiments of the present invention have been described above based on some embodiments. However, the embodiments of the present invention described above are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell 20 ... Single cell 25 ... Fuel cell stack 30 ... End member 100 ... Separator for anode side fuel cells 101-106 ... Opening hole 110 ... Resin member 112 ... Gasket holding groove 114 ... Gasket shoulder 116 ... First crack Guide groove 117 ... Seal line 118 ... Second crack guide groove 119 ... Crack guide groove 120 ... Resin member 122 ... Gasket holding groove 124 ... Gasket shoulder 125 ... Protrusion for seal 126 ... First crack guide groove 128 ... Second Crack induction groove 130 ... reinforcing member 200 ... gasket 210 ... adhesive 302, 304, 306, 308 ... crack 400 ... resin frame 500 ... cathode side fuel cell separator 501 to 506 ... opening hole 510 ... resin member 512 ... gasket holding Groove 516 ... First crack induction groove 530 ... Reinforcing member

Claims (7)

A fuel cell separator,
A resin member;
A reinforcing member for reinforcing the resin member;
With
The resin member has a surface opposite to the reinforcing member,
A seal line for sealing a fluid used in a fuel cell;
A crack-inducing groove running in parallel with the seal line;
A fuel cell separator. The fuel cell separator according to claim 1,
Two or more crack induction grooves are provided across the seal line, the fuel cell separator. The fuel cell separator according to claim 1 or 2,
The fuel cell separator, wherein a thickness of the resin member at a bottom portion of the crack induction groove is smaller than a thickness of the resin member at a central portion of the seal line. In the fuel cell separator according to claim 3,
The fuel cell separator, wherein the thickness of the resin member at the bottom of the crack induction groove is not more than half of the thickness of the resin member at the center of the seal line. In the fuel cell separator according to any one of claims 1 to 4,
The resin member has a gasket holding groove for holding the gasket,
The separator for a fuel cell, wherein the seal line and the crack induction groove are formed in the gasket holding groove. The fuel cell separator according to claim 5, wherein
A fuel cell separator comprising a second crack induction groove on an outer edge side of the gasket holding groove. The fuel cell separator according to claim 6, wherein
The fuel cell separator, wherein a thickness of the resin member at a bottom portion of the second crack induction groove is smaller than a thickness of the resin member at a central portion of the seal line.

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