Stacked Structure of Fuel Cell Separators

Abstract

Provided is a layered structure for a fuel-cell separator, and with the layered structure a stable reaction force at opposing reception parts can be ensured and over-compression of a bead part can be effectively suppressed even if set deviation has occurred in a layered separator. The present invention comprises: a first set 11 having one separator 12; and a second set 21 having another separator 22. Each of the one separator 21 and the other separator 22 includes: bead parts 14, 24; and reception parts 16, 26 for receiving an over-compression load of the bead parts14, 24. The one separator 12 and the other separator 22 are disposed opposing each other so that the surfaces on the sides at which the bead parts 14, 24 and the reception parts 16, 26 are protruding face each other. The separators are configured so that a direction in which the reception part 26 of the one separator 12 extends linearly and a direction in which the reception part 26 of the other separator 22 extends linearly are non-parallel, and also so that the opposing reception parts 16, 26 partially overlap each other.

Description

Technical Field

[0001] The present invention relates to a laminated structure of fuel cell separators. More specifically, it relates to a laminated structure of fuel cell separators in which two or more fuel cell separators are laminated.

Background Art

[0002] In recent years, fuel cells (i.e., fuel cell stacks) have been developed for fuel cell vehicles and the like. This fuel cell stack includes a laminated structure in which a plurality of unit cells are laminated, and a housing that houses this laminated structure. And, the unit cell has, as main components, an electrolyte membrane, electrodes, gas flow paths, a fuel cell separator, etc., and has a mechanism in which a fuel gas such as hydrogen is supplied from the anode side and an oxidizing gas such as air is supplied from the cathode side to generate electricity.

[0003] One of the sealing structures of fuel cells has a configuration in which a seal is secured by the reaction force of a bead portion (see, for example, FIGS. 2 and 3 of Patent Document 1). For example, Patent Document 1 discloses a fuel cell including a membrane electrode gas diffusion layer assembly in which a membrane electrode assembly is sandwiched between a pair of gas diffusion layers, a frame-shaped insulating member that abuts on the outer peripheral portion of the membrane electrode gas diffusion layer assembly, and first and second separators that sandwich the membrane electrode gas diffusion layer assembly and the insulating member.

[0004] By the way, when compressing the separators having the above-described sealing structure in a laminated state, the compression state of each bead portion becomes non-uniform, and some bead portions are over-compressed and damaged, and the sealing performance of the fuel cell may be impaired.

[0005] As a countermeasure to prevent such over-compression of the bead portion, a technique has been proposed in which a receiving portion for preventing over-compression of the bead portion is provided around the bead portion of the separator (see, for example, Patent Document 2). For example, Patent Document 2 discloses a fuel cell stack assembly including at least one bipolar plate including at least one raised bead portion and at least one raised limiter. In the fuel cell stack assembly described in Patent Document 2, the above-described raised limiter functions as a receiving portion for preventing over-compression of the bead portion, and by adding such a limiter, it is said that excessive compression can be prevented and leakage in the fuel cell and failure of the fuel cell stack can be suppressed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, even if a receiving portion for preventing over-compression of the bead portion is provided around the bead portion, if misalignment (for example, positional misalignment between stacked separators) occurs during stacking of the separators, there has been a problem that it becomes difficult to suppress over-compression of the bead portion.

[0008] For example, as a receiving portion for preventing over-compression of the bead portion, there is a protruding portion provided around the bead portion. Such a receiving portion receives over-compression of the bead portion at the top and upper surfaces of the protruding receiving portion. Therefore, for example, when the top and upper surfaces of the receiving portion are arc-shaped, the center side of the top and upper surfaces becomes a high reaction force portion. However, if misalignment occurs during the lamination of the separators, the high reaction force portions of the opposing receiving portions (i.e., the center side of the top and upper surfaces) do not come into contact with each other, and the reaction force of the receiving portion decreases. Also, when the top and upper surfaces of the receiving portion are flat, both end sides of the flat top and upper surfaces become high reaction force portions. However, if misalignment occurs during the lamination of the separators, as in the above-described case, the high reaction force portions of the opposing receiving portions do not come into contact with each other, and the reaction force of the receiving portion decreases. Although it is conceivable to laminate the separators so that misalignment does not occur and suppress a decrease in the reaction force of the receiving portion, extremely high accuracy is required during the lamination of the separators. For example, there is also a possibility that assembly accuracy exceeding the assembly accuracy required from the viewpoint of the performance of the fuel cell may be necessary.

[0009] In response to such problems, even when misalignment occurs in the separator, it is possible to maintain a good contact state between the opposing receiving portions, and it is possible to effectively prevent over-compression of the bead portion by the contact between the receiving portions. There has been a strong desire to develop a laminated structure of a fuel cell separator with excellent robustness.

[0010] In view of the above problems, according to the present invention, there is provided a laminated structure of a fuel cell separator with excellent robustness in which performance degradation due to external influences such as misalignment of the separator is effectively suppressed.

Means for Solving the Problems

[0011] To solve the above problems, the present invention provides the following laminated structure of a fuel cell separator.

[0012] [1] A laminated structure of fuel cell separators in which two or more fuel cell separators constituting a unit cell of a fuel cell stack are laminated, A first set having one separator and a second set having other separators, the one separator and the other separator each have a bead portion protruding toward one surface side and a receiving portion for receiving an over-compression load of the bead portion, protruding linearly in the same direction as the bead portion, the one separator and the other separator are arranged to face each other such that the surfaces on the side where the bead portion and the receiving portion protrude face each other, A stacked structure of fuel cell separators, configured such that the direction in which the receiving portion of the one separator extends linearly and the direction in which the receiving portion of the other separator extends linearly are non-parallel, and a part of the opposing receiving portions overlap each other.

[0013] [2] The first set including the first separator and the second separator stacked in the plate thickness direction, and the second set including the third separator and the fourth separator stacked in the plate thickness direction, the second separator has a second bead portion protruding toward a second outer surface side opposite to a first contact surface where the stacked first separator and the second separator contact each other, and a second receiving portion for receiving an over-compression load of the second bead portion, protruding linearly in the same direction as the second bead portion, the third separator has a third bead portion protruding toward a third outer surface side opposite to a second contact surface where the stacked third separator and the fourth separator contact each other, and a third receiving portion for receiving an over-compression load of the third bead portion, protruding linearly in the same direction as the third bead portion, the first set and the second set are stacked such that the second outer surface side of the second separator constituting the first set faces the third outer surface side of the third separator constituting the second set, The fuel cell separator laminate structure according to [1], wherein the direction in which the second receiving portion of the second separator extends linearly and the direction in which the third receiving portion of the third separator extends linearly are configured to be non-parallel, and a part of the second receiving portion and the third receiving portion are arranged to face each other so as to overlap.

[0014] [3] The first separator has a first bead portion protruding toward the first outer surface side opposite to the first contact surface, and a first receiving portion protruding linearly in the same direction as the first bead portion to receive the over-compression load of the first bead portion. The fuel cell separator laminate structure according to [2], wherein the direction in which the first receiving portion of the first separator extends linearly and the direction in which the second receiving portion of the second separator extends linearly are configured to be parallel.

[0015] [4] The fuel cell separator laminate structure according to [3], wherein the first receiving portion and the second receiving portion are formed to be mirror-symmetrical with respect to the first contact surface.

[0016] [5] The fourth separator has a fourth bead portion protruding toward the fourth outer surface side opposite to the second contact surface, and a fourth receiving portion protruding linearly in the same direction as the fourth bead portion to receive the over-compression load of the fourth bead portion. The fuel cell separator laminate structure according to [2], wherein the direction in which the third receiving portion of the third separator extends linearly and the direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be parallel.

[0017] [6] The fuel cell separator laminate structure according to [5], wherein the third receiving portion and the fourth receiving portion are formed to be mirror-symmetrical with respect to the second contact surface.

[0018] [7] The first separator has a first bead portion protruding toward the first outer surface side opposite to the first contact surface, and a first receiving portion protruding linearly in the same direction as the first bead portion for receiving the over-compression load of the first bead portion. The fuel cell separator laminate according to [2] above, wherein a direction in which the first receiving portion of the first separator extends linearly and a direction in which the second receiving portion of the second separator extends linearly are configured to be non-parallel.

[0019] [8] The fuel cell separator laminate according to [7] above, wherein a direction in which the first receiving portion of the first separator extends linearly and a direction in which the third receiving portion of the third separator extends linearly are configured to be parallel.

[0020] [9] The fourth separator has a fourth bead portion protruding toward the fourth outer surface side opposite to the second contact surface, and a fourth receiving portion protruding linearly in the same direction as the fourth bead portion for receiving the over-compression load of the fourth bead portion. The fuel cell separator laminate according to [2] above, wherein a direction in which the third receiving portion of the third separator extends linearly and a direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be non-parallel.

[0021]

[10] The fuel cell separator laminate according to [9] above, wherein a direction in which the second receiving portion of the second separator extends linearly and a direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be parallel.

[0022]

[11] The fuel cell separator laminate according to any one of [1] to

[10] above, wherein two directions in which the opposing receiving portions extend linearly form an angle of 5 to 90°.

[0023]

[12] In the one separator of the first set and / or the other separator of the second set, in the fuel cell separator laminate structure according to any one of [1] to

[10] , the protruding height of the receiving portion is smaller than the protruding height of the bead portion.

Advantages of the Invention

[0024] The above-described fuel cell separator laminate structure can prevent over-compression of the bead portion. In particular, even if misalignment occurs in the stacked separators, the tops of the opposing receiving portions overlap, suppressing a decrease in the reaction force of the receiving portion. Thereby, a stable reaction force can be ensured at the opposing receiving portions, suppressing over-compression of the bead portion, and effectively suppressing deterioration of the bead portion. As described above, the fuel cell separator laminate structure effectively suppresses performance degradation due to external influences such as misalignment of the separators and is excellent in robustness.

Brief Description of the Drawings

[0025]

Figure 1

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Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

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Figure 14

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Figure 16

Figure 17

Figure 18

Embodiments for Carrying Out the Invention

[0026] Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be understood that the present invention is not limited to the following embodiments, and design changes, improvements, etc. can be appropriately added based on the ordinary knowledge of those skilled in the art without departing from the gist of the present invention.

[0027] One embodiment of the stacked structure of this fuel cell separator is a stacked structure 100 of a fuel cell separator including a first set 11 as shown in FIGS. 1 and 2 and a second set 21 as shown in FIGS. 3 and 4. The stacked structure 100 of the fuel cell separator includes at least such two sets (the first set 11 and the second set 21). The first set 11 has a separator 12 (for example, the second separator 12b), and the second set 21 has another separator 22 (for example, the third separator 22a). One separator 12 and the other separator 22 each have bead portions 14, 24 protruding toward one surface side and receiving portions 16, 26 protruding linearly in the same direction as the bead portions 14, 24 for receiving the over-compression load of the bead portions 14, 24.

[0028] In the stacked structure 100 of the fuel cell separator, one separator 12 and the other separator 22 are oppositely arranged such that the surfaces on the side where the bead portions 14, 24 and the receiving portions 16, 26 protrude face each other. And the direction in which the receiving portion 16 of one separator 12 extends linearly and the direction in which the receiving portion 26 of the other separator 22 extends linearly are configured to be non-parallel, and a part of the opposing receiving portions 16, 26 overlap each other.

[0029] The first set 11 and the second set 21 are, more specifically, in the stacked structure 100 of the fuel cell separator, as shown in FIGS. 5 and 6, stacked such that the second outer surface 12Q side of the second separator 12b constituting the first set 11 faces the third outer surface 22P side of the third separator 22a constituting the second set 21. The first set 11 and the second set 21 are plate-shaped made of metal that constitute the unit cells 10, 20 in the fuel cell stack. After stacking a plurality of unit cells 10, 20, the fuel cell stack is in a state where an external force is applied in the stacking direction so that these unit cells 10, 20 do not shift and are fastened. For example, the stacked structure 100 of the fuel cell separator can be used as a fuel cell stack 300 including a stacked structure 100 of a plurality of unit cells 10 as shown in FIG. 18. FIG. 18 is a perspective view schematically showing the configuration of the fuel cell stack 300.

[0030] Here, FIG. 1 is a plan view schematically showing a first set in one embodiment of the stacked structure of the fuel cell separator, and FIG. 2 is a cross-sectional perspective view showing the configuration of the AA cross-section of FIG. 1. FIG. 3 is a plan view schematically showing a second set in one embodiment of the stacked structure of the fuel cell separator. FIG. 4 is a cross-sectional perspective view showing the configuration of the BB cross-section of FIG. 3. FIG. 5 is a partial cross-sectional view schematically showing a part of a cross-section cut along the stacking direction of the unit cells of a fuel cell stack including a unit cell having one embodiment of the fuel cell separator. FIG. 6 is a perspective view schematically showing one embodiment of the stacked structure of the fuel cell separator.

[0031] Note that the unit cells 10 and 20 are made of metal, for example, and constitute a polymer electrolyte fuel cell or the like. The unit cells 10 and 20 have, for example, a membrane electrode assembly 51 sandwiched between a first set 11 and a second set 21, and a gas flow path 50 provided between the membrane electrode assembly 51 and the first set 11 and the second set 21, in addition to a pair of first set 11 and second set 21 that constitute the laminated structure 100 of the fuel cell separator. The membrane electrode assembly 51 has, for example, an electrolyte membrane 52 made of a polymer electrolyte membrane or the like, a pair of electrolyte catalyst layers 53 sandwiching the electrolyte membrane 52, and a gas diffusion layer 58 disposed so as to cover the electrolyte catalyst layer 53. The unit cells 10 and 20 as fuel cells are members that generate electricity by a chemical reaction between hydrogen (fuel gas) supplied from the anode side and oxygen (oxidant gas) supplied from the cathode side.

[0032] The first set 11 is composed of, for example, two separators 12 laminated in the plate thickness direction. Hereinafter, one separator 12 constituting the first set 11 is referred to as a first separator 12a, and the other separator 12 is referred to as a second separator 12b. Also, the surface where the laminated first separator 12a and second separator 12b contact each other is referred to as a first contact surface 12O. Then, the surface of the first separator 12a opposite to the first contact surface 12O is referred to as a first outer surface 12P, and the surface of the second separator 12b opposite to the first contact surface 12O is referred to as a second outer surface 12Q.

[0033] Similarly, the second set 21 is composed of, for example, two separators 22 laminated in the plate thickness direction. Hereinafter, one separator 22 constituting the second set 21 is referred to as a third separator 22a, and the other separator 22 is referred to as a fourth separator 22b. Also, the surface where the laminated third separator 22a and fourth separator 22b contact each other is referred to as a second contact surface 22O. Then, the surface of the third separator 22a opposite to the second contact surface 22O is referred to as a third outer surface 22P, and the surface of the fourth separator 22b opposite to the second contact surface 22O is referred to as a fourth outer surface 22Q.

[0034] The first separator 12a has a first bead portion 14a that protrudes toward the first outer surface 12P side, and a first receiving portion 16a that linearly protrudes in the same direction as the first bead portion 14a to receive the over-compression load of the first bead portion 14a.

[0035] The second separator 12b has a second bead portion 14b that protrudes toward the second outer surface 12Q side, and a second receiving portion 16b that linearly protrudes in the same direction as the second bead portion 14b to receive the over-compression load of the second bead portion 14b.

[0036] The third separator 22a has a third bead portion 24a that protrudes toward the third outer surface 22P side, and a third receiving portion 26a that linearly protrudes in the same direction as the third bead portion 24a to receive the over-compression load of the third bead portion 24a.

[0037] The fourth separator 22b has a fourth bead portion 24b that protrudes toward the fourth outer surface 22Q side, and a fourth receiving portion 26b that linearly protrudes in the same direction as the fourth bead portion 24b to receive the over-compression load of the fourth bead portion 24b.

[0038] Hereinafter, the first bead portion 14a, the second bead portion 14b, the third bead portion 24a, and the fourth bead portion 24b may be collectively referred to simply as the "bead portions 14, 24". Similarly, the first receiving portion 16a, the second receiving portion 16b, the third receiving portion 26a, and the fourth receiving portion 26b may be collectively referred to simply as the "receiving portions 16, 26".

[0039] The bead portions 14 and 24 are convex portions where the first set 11 and the second set 21 of adjacent unit cells 10 and 20 are in contact, and the shape on the plane of the laminated structure 100 of the fuel cell separator is not particularly limited. For example, those forming an annular shape on the plane of the laminated structure 100 of the fuel cell separator (see, for example, FIGS. 1 and 3) can be mentioned, but it does not have to be annular. For example, the shape of the bead portions 14 and 24 on the plane of the laminated structure 100 of the fuel cell separator may be a mirror image shape with respect to adjacent unit cells 10 and 20 (that is, the first set 11 and the second set 21). For example, when the bead portion 14 of the first set 11 and the bead portion 24 of the second set 21 are in a mirror image shape, both bead portions 14 and 24 come into contact in the laminated structure 100 of the fuel cell separator. A sealing material 54 may be provided at the vertex portions of the bead portions 14 and 24 so as to be in contact with adjacent unit cells 10 and 20.

[0040] In the laminated structure 100 of the present fuel cell separator, the receiving portions 16 and 26 for receiving the over-compression load of the bead portions 14 and 24 have a particularly main configuration. That is, the laminated structure 100 of the present fuel cell separator is configured such that the direction in which the second receiving portion 16b of the second separator 12b extends linearly and the direction in which the third receiving portion 26a of the third separator 22a extends linearly are non-parallel, and a part of each of the second receiving portion 16b and the third receiving portion 26a is arranged to overlap each other. By configuring in this way, over-compression of the bead portions 14 and 24 can be extremely effectively prevented. That is, even when a set misalignment occurs between the first set 11 and the second set 21, the contact of the high reaction force portions can be kept good by the tops of the opposing second receiving portion 16b and third receiving portion 26a overlapping each other, and a decrease in the reaction force of the second receiving portion 16b and the third receiving portion 26a can be suppressed. Thereby, a stable reaction force can be ensured at the second receiving portion 16b and the third receiving portion 26a, over-compression of the bead portions 14 and 24 can be suppressed, and deterioration of the bead portions 14 and 24 can be effectively suppressed. Therefore, the laminated structure 100 of the present fuel cell separator is effectively suppressed from performance degradation due to external influences such as set misalignment and is excellent in robustness.

[0041] The second receiving portion 16b and the third receiving portion 26a are linear protruding portions for receiving the over-compression load of the bead portions 14 and 24. As described above, if the linearly extending directions of the two are non-parallel, the shape on the plane of the stacked structure 100 of the fuel cell separator is not particularly limited. For example, the second receiving portion 16b and the third receiving portion 26a are preferably configured to be linear with both ends on the plane of the stacked structure 100 of the fuel cell separator and arranged in a non-parallel positional relationship such that a part of each other intersects. Further, there is no particular limitation on the cross-sectional shape orthogonal to the linearly extending direction of the second receiving portion 16b and the third receiving portion 26a. Hereinafter, the cross-sectional shape orthogonal to the linearly extending direction of the receiving portions 16 and 26 may be simply referred to as the "cross-sectional shape" of the receiving portions 16 and 26. The specific cross-sectional shapes and the shapes of the top and bottom surfaces of each of the receiving portions 16 and 26 will be described later.

[0042] The stacked structure 100 of the present fuel cell separator only needs to be arranged such that the receiving portions 16 and 26 protruding from the opposing surfaces (the second outer surface 12Q and the third outer surface 22P) of the stacked first set 11 and second set 21 have a non-parallel positional relationship, and there is no particular limitation on the other receiving portions 16 and 26. However, in the stacked structure 100 of the present fuel cell separator, another set (not shown) having another separator may be arranged on the first outer surface 12P side of the first set 11 or the fourth outer surface 22Q side of the second set 21, and it is preferable that the opposing receiving portions 16 and 26 of these other sets also have a non-parallel positional relationship.

[0043] The first set 11 shown in FIGS. 2 and 6 is configured such that the linearly extending direction of the first receiving portion 16a of the first separator 12a and the linearly extending direction of the second receiving portion 16b of the second separator 12b are parallel. For example, in the first set 11 configured in this way, the first receiving portion 16a and the second receiving portion 16b may be formed to be mirror-symmetrical with respect to the first contact surface 12O.

[0044] Further, in the second set 21 shown in FIGS. 4 and 6, the third receiving portion 26a of the third separator 22a and the fourth receiving portion 26b of the fourth separator 22b are configured to be parallel to each other in the direction in which they linearly extend. For example, in the second set 21 configured in this way, the third receiving portion 26a and the fourth receiving portion 26b may be formed to be mirror-symmetrical with respect to the second contact surface 22O.

[0045] The fuel cell separator laminate 100 including the first set 11 and the second set 21 as shown in FIG. 6 has extremely excellent stability when the first set 11 and the second set 21 are laminated, and can achieve stable sealing performance by the bead portions 14 and 24.

[0046] Further, the fuel cell separator laminate may be the fuel cell separator laminate 200 configured as shown in FIGS. 7 to 9. Here, FIG. 7 is a cross-sectional perspective view showing the configuration of the first set in another embodiment of the fuel cell separator laminate. FIG. 8 is a cross-sectional perspective view showing the configuration of the second set in another embodiment of the fuel cell separator laminate. FIG. 9 is a perspective view schematically showing another embodiment of the fuel cell separator laminate.

[0047] The fuel cell separator laminate 200 shown in FIG. 9 includes the first set 31 as shown in FIG. 7 and the second set 41 as shown in FIG. 8. Similar to the fuel cell separator laminate 100 (for example, see FIG. 6) described so far, the first set 31 has the first separator 32a and the second separator 32b laminated in the plate thickness direction. The second set 41 also has the third separator 42a and the fourth separator 42b laminated in the plate thickness direction.

[0048] The first separator 32a has a first bead portion 34a protruding toward the first outer surface 32P side, and a first receiving portion 36a linearly protruding in the same direction as the first bead portion 34a. Further, the second separator 32b has a second bead portion 34b protruding toward the second outer surface 32Q side, and a second receiving portion 36b linearly protruding in the same direction as the second bead portion 34b.

[0049] The third separator 42a has a third bead portion 44a protruding toward the third outer surface 42P side, and a third receiving portion 46a linearly protruding in the same direction as the third bead portion 44a. The fourth separator 42b has a fourth bead portion 44b protruding toward the fourth outer surface 42Q side, and a fourth receiving portion 46b linearly protruding in the same direction as the fourth bead portion 44b.

[0050] The stacked structure 200 of the fuel cell separators is also configured such that the direction in which the second receiving portion 36b of the second separator 32b linearly extends and the direction in which the third receiving portion 46a of the third separator 42a linearly extends are non-parallel, and a part of the second receiving portion 36b and the third receiving portion 46a are opposed and arranged so as to overlap each other. However, in the stacked structure 200 of the fuel cell separators, the shapes of the first receiving portion 36a of the first separator 32a constituting the first set 31 and the fourth receiving portion 46b of the fourth separator 42b constituting the second set 41 are different from those of the stacked structure 100 of the fuel cell separators shown in FIG. 6.

[0051] Specifically, as shown in FIGS. 7 and 9, in the first set 31, the direction in which the first receiving portion 36a of the first separator 32a linearly extends and the direction in which the second receiving portion 36b of the second separator 32b linearly extends are configured to be non-parallel.

[0052] Further, as shown in FIGS. 8 and 9, in the second set 41, the direction in which the third receiving portion 46a of the third separator 42a linearly extends and the direction in which the fourth receiving portion 46b of the fourth separator 42b linearly extends are configured to be non-parallel.

[0053] On the one hand, the stacked structure 200 of the fuel cell separator is configured such that the direction in which the first receiving portion 36a of the first separator 32a constituting the first set 31 linearly extends and the direction in which the third receiving portion 46a of the third separator 42a constituting the second set 41 linearly extends are parallel.

[0054] Also, the stacked structure 200 of the fuel cell separator is configured such that the direction in which the second receiving portion 36b of the second separator 32b constituting the first set 31 linearly extends and the direction in which the fourth receiving portion 46b of the fourth separator 42b constituting the second set 41 linearly extends are parallel.

[0055] In the stacked structure 200 of the fuel cell separator, the shapes of the first set 31 and the second set 41 are substantially the same. That is, the stacked structure 200 of the fuel cell separator uses the first set 31 and the second set 41 that become unit cells 20 and 40, respectively, in which a pair of separators 32 and 42 are formed non-mirror symmetrically with respect to their respective contact surfaces (the first contact surface 32O and the second contact surface 42O). By configuring in this way, by stacking substantially one type of separator, the linearly extending directions of the opposing receiving portions 36 and 46 can be made non-parallel, and the performance degradation due to set misalignment can be effectively suppressed.

[0056] Of course, the shapes and the linearly extending directions of the first receiving portion 36a of the first separator 32a and the fourth receiving portion 46b of the fourth separator 42b are not limited to those described so far. As described above, they can be appropriately changed according to various situations such as when another set having another separator is further provided.

[0057] Returning to FIGS. 1 to 6, the description of the stacked structure 100 of the fuel cell separator will be continued.

[0058] The separators 12 and 22 that constitute the first set 11 and the second set 21 are plate-shaped members made of metal. Regarding the material, there is no particular limitation as long as it is metal, and the same materials as those of conventionally known metal separators can be adopted. For example, the materials of the separators 12 and 22 can include stainless steel, titanium, and the like.

[0059] The first separator 12a and the second separator 12b that constitute the first set 11 may be joined to each other, or may simply be overlapped and laminated. Similarly, the third separator 22a and the fourth separator 22b that constitute the second set 21 may be joined to each other, or may simply be overlapped and laminated.

[0060] The first set 11 and the second set 21 are provided with communication holes 18 that communicate with each other in the stacking direction for supplying and discharging an oxidant gas and a fuel gas. For example, the communication holes 18 are preferably provided at the edge of either the first set 11 or the second set 21.

[0061] The bead portions 14 and 24 protrude, for example, toward the electrolyte membrane 52, and are formed, for example, over the entire outer periphery of the stacked structure 100 of the fuel cell separator so as to be endless. Also, when the communication holes 18 are provided, they may be formed so as to surround the communication holes 18.

[0062] The receiving portions 16, 26 are linear protrusions projecting in the same direction as the bead portions 14, 24 of the respective separators 12, 22, and are preferably provided, for example, around the respective bead portions 14, 24. For example, the receiving portions 16, 26 are preferably provided within a predetermined range near the bead line of the bead portions 14, 24 of the respective separators 12, 22. For example, the practical distance from the hem of the bead line of the bead portion 14, 24 to the hem of the adjacent receiving portion 16, 26 is, for example, 1 mm or more. The distance between the bead line of the bead portion 14, 24 and the receiving portion 16, 26 is the mutual distance between the hems of the respective protrusions. The receiving portions 16, 26 are preferably provided in the range of 1 to 30 mm from the bead portions 14, 24 of the respective separators 12, 22. By configuring in this way, when an over-compression load occurs in the adjacent bead portions 14, 24, the over-compression load can be effectively received.

[0063] The protruding height of the receiving portions 16, 26 is preferably smaller than the protruding height of the bead portions 14, 24 of the respective separators 12, 22. For example, the protruding height of the second receiving portion 16b toward the second outer surface 12Q side is smaller than the protruding height of the second bead portion 14b toward the second outer surface 12Q side, and the protruding height of the third receiving portion 26a toward the third outer surface 22P side is preferably smaller than the protruding height of the third bead portion 24a toward the third outer surface 22P side. Incidentally, the protruding height of the first receiving portion 16a toward the first outer surface 12P side may be smaller than the protruding height of the first bead portion 14a toward the first outer surface 12P side. Further, the protruding height of the fourth receiving portion 26b toward the fourth outer surface 22Q side may be smaller than the protruding height of the fourth bead portion 24b toward the fourth outer surface 22Q side.

[0064] The receiving portions 16 and 26 may be a single linear protrusion or a plurality of linear protrusions with respect to the bead lines of the bead portions 14 and 24. For example, in the stacked structure 100 of this fuel cell separator, an example is shown in which three linear receiving portions 16 and 26 are provided respectively with respect to the bead lines of the bead portions 14 and 24. The receiving portions 16 and 26 may be provided inside the bead lines of the bead portions 14 and 24, may be provided outside the bead lines of the bead portions 14 and 24, or may be provided on both the inside and outside of the bead lines of the bead portions 14 and 24.

[0065] In the stacked structure 100 of the fuel cell separator, the configuration in which the opposing receiving portions 16 and 26 are non-parallel to each other means that the linearly extending direction of one receiving portion 16 and the linearly extending direction of the other receiving portion 26 are not parallel, and the opposing receiving portions 16 and 26 are arranged to face each other such that a part of each other overlaps. That is, the receiving portions 16 and 26 configured to be non-parallel are such that the non-overlapping portions of either one of the receiving portions 16 and 26 serve as an adjustment margin for allowing displacement in the case of misalignment during stacking. For example, the linearly extending direction of the opposing receiving portions 16 and 26 is preferably a direction in which the linearly extending direction of the other is inclined by 5 to 90°, more preferably 10 to 90°, with respect to the linearly extending direction of one. In particular, when the inclination angle of the linearly extending direction of the above-described opposing receiving portions 16 and 26 is 10 to 90°, it becomes possible to make the length of the receiving portions 16 and 26 shorter, and by setting the range of the receiving portions 16 and 26 smaller, it contributes to the downsizing of the stacked structure 100 of the fuel cell separator. However, in the opposing receiving portions 16 and 26 configured to be non-parallel, if an adjustment margin for allowing displacement in the case of misalignment as described above can be sufficiently ensured, the inclination angle (i.e., the intersecting angle of the linearly extending directions) may be smaller than the above-described angle range. Incidentally, as factors for misalignment between separators in the stacked structure 100 of the fuel cell separator, for example, a composite factor of dimensional variation of the separator and displacement in the bonding position can be cited.

[0066] Also, when each receiving portion 16, 26 is provided so as to be close to the bead portions 14, 24 of the respective separators 12, 22, the linearly extending direction of each receiving portion 16, 26 is parallel or inclined at 45° or less with respect to the extending direction of the bead line of the bead portion 14, 24, which is preferable.

[0067] There is no particular limitation on the cross-sectional shape and the shape of the top and bottom surfaces of the receiving portions 16, 26, and any shape can be used as long as it can receive the over-compression load of the bead portion 14, 24. For example, the receiving portions 16, 26 may have a curved shape for the shape of the top and bottom surfaces 16X as in the receiving portion 16 (second receiving portion 16b) shown in FIG. 10. In the receiving portion 16 having such a shape, the central side of the top and bottom surfaces 16X becomes the high reaction force portion 19. Then, a reaction force is generated in the direction indicated by the arrow in FIG. 10. In FIG. 10, the magnitude of the generated reaction force is schematically represented by the size of the arrow. For example, FIG. 11 shows an example in which the receiving portions 16, 26 having the curved shape of the top and bottom surfaces 16X as described above are arranged opposite to each other. By arranging the receiving portions 16, 26 opposite to each other as in FIG. 11, even if a set misalignment occurs during the lamination of each set having each separator (also simply referred to as "during the lamination of the separators"), the high reaction force portions 19 of each other can come into good contact with each other, and over-compression of the bead portion (not shown) can be effectively prevented. Here, FIG. 10 is an enlarged perspective view for explaining an example of the receiving portion in the separator, and FIG. 11 is a perspective view for explaining the generation state of the reaction force received by the receiving portion shown in FIG. 10.

[0068] Further, for example, like the receiving part 16 (second receiving part 16b) shown in FIG. 12, the shape of the top surface 16X may be flat. In the receiving part 16 with such a shape, both end sides of the top surface 16X become high reaction force parts 19. And a reaction force is generated in the direction indicated by the arrow in FIG. 12. In FIG. 12, the magnitude of the generated reaction force is schematically represented by the size of the arrow. For example, FIG. 13 shows an example in the case where the receiving parts 16 and 26 with the flat top surface 16X as described above are arranged opposite to each other. By arranging the receiving parts 16 and 26 opposite to each other as in FIG. 13, even if a set shift occurs during the lamination of the separators, the high reaction force parts 19 of each other can contact each other well, and over-compression of the bead part (not shown) can be effectively prevented. Here, FIG. 12 is an enlarged perspective view for explaining another example of the receiving part in the separator, and FIG. 13 is a perspective view for explaining the generation state of the reaction force received by the receiving part shown in FIG. 12.

[0069] Also, each of the receiving parts 16 and 26 may have a shape as shown in FIGS. 14 to 17, for example. For example, the receiving part 56 shown in FIG. 14 has a cross-sectional shape that protrudes in two steps. That is, the receiving part 56 has a second protrusion 57 on the protruding top surface side. The receiving part 66 shown in FIG. 15 has a groove part 67 that is recessed inward on the top surface side. The receiving part 76 shown in FIG. 16 has a side groove part 77 that is recessed inward on the inclined surface part that protrudes toward the top surface side. The receiving part 86 shown in FIG. 17 has a recessed part 87 (dimple part) that is recessed inward on the top surface side. Thus, each of the receiving parts 16 and 26 may not only be a simple protrusion protruding in one direction, but may also be appropriately provided with a recessed groove part, a recessed part, etc. with respect to the top surface or the inclined surface part that becomes the side surface of the protrusion.

[0070] The manufacturing method of the fuel cell separator laminate structure is not particularly limited. For example, a method of press-working a flat plate made of metal to form a bead part and a receiving part can be mentioned.

Industrial Applicability

[0071] The laminated structure of the fuel cell separator of the present invention can be used as a fuel cell separator for an in-vehicle fuel cell stack used in vehicles and the like.

Explanation of Signs

[0072] 10, 30: Unit cell 11, 31: First set 12, 32: Separator 12a, 32a: First separator 12b, 32b: Second separator 12O, 32O: First contact surface 12P, 32P: First outer surface 12Q, 32Q: Second outer surface 14, 34: Bead portion 14a, 34a: First bead portion 14b, 34b: Second bead portion 16, 36: Receiving portion 16a, 36a: First receiving portion 16b, 36b: Second receiving portion 16X: Top surface (top surface of the receiving portion) 18: Communication hole 19: High reaction force portion 20, 40: Unit cell 21, 41:: Second set 22, 42: Separator 22a, 42a: Third separator 22b, 42b: Fourth separator 22O, 42O: Second contact surface 22P, 42P: Third outer surface 22Q, 42Q: Fourth outer surface 24, 44: Bead portion 24a, 44a: Third bead portion 24b, 44b: Fourth bead portion 16, 36: Receiving portion 26a, 46a: Third receiving portion 26b, 46b: Fourth receiving portion 50: Gas flow path 51: Membrane electrode assembly 52: Electrolyte membrane 53: Electrolyte catalyst layer 54: Sealing material 56, 66, 76, 86: Receiving part 57: Second protrusion 58: Gas diffusion layer 67: Groove part 77: Side groove part 87: Depression part (dimple part) 100: Stacked structure of fuel cell separators 200: Stacked structure of fuel cell separators 300: Fuel cell stack

Claims

1. A stacked structure of fuel cell separators in which two or more fuel cell separators constituting a unit cell of a fuel cell stack are stacked, comprising a first set having one separator and a second set having another separator, wherein the one separator and the other separator each have a bead portion protruding toward one surface side and a receiving portion protruding linearly in the same direction as the bead portion for receiving an over-compression load of the bead portion, the one separator and the other separator are oppositely arranged such that the surfaces on the side where the bead portion and the receiving portion protrude face each other, a stacked structure of fuel cell separators, wherein a direction in which the receiving portion of the one separator extends linearly and a direction in which the receiving portion of the other separator extends linearly are configured to be non-parallel, and a part of the opposing receiving portions overlap each other.

2. the first set comprising the first separator and the second separator stacked in the plate thickness direction, the second set comprising the third separator and the fourth separator stacked in the plate thickness direction, the second separator has a second bead portion protruding toward a second outer surface side opposite to a first contact surface where the stacked first separator and the second separator contact each other, and a second receiving portion protruding linearly in the same direction as the second bead portion for receiving an over-compression load of the second bead portion, the third separator has a third bead portion protruding toward a third outer surface side opposite to a second contact surface where the stacked third separator and the fourth separator contact each other, and a third receiving portion protruding linearly in the same direction as the third bead portion for receiving an over-compression load of the third bead portion, the first set and the second set are stacked such that the second outer surface side of the second separator constituting the first set faces the third outer surface side of the third separator constituting the second set, a stacked structure of fuel cell separators according to claim 1, wherein a direction in which the second receiving portion of the second separator extends linearly and a direction in which the third receiving portion of the third separator extends linearly are configured to be non-parallel, and a part of the second receiving portion and the third receiving portion are oppositely arranged so as to overlap each other.

3. The first separator has a first bead portion protruding toward the first outer surface side opposite to the first contact surface, and a first receiving portion protruding linearly in the same direction as the first bead portion for receiving the over-compression load of the first bead portion. The fuel cell separator laminate according to claim 2, wherein a direction in which the first receiving portion of the first separator extends linearly and a direction in which the second receiving portion of the second separator extends linearly are configured to be parallel.

4. The fuel cell separator laminate according to claim 3, wherein the first receiving portion and the second receiving portion are formed to be mirror-symmetrical with respect to the first contact surface.

5. The fourth separator has a fourth bead portion protruding toward the fourth outer surface side opposite to the second contact surface, and a fourth receiving portion protruding linearly in the same direction as the fourth bead portion for receiving the over-compression load of the fourth bead portion. The fuel cell separator laminate according to claim 2, wherein a direction in which the third receiving portion of the third separator extends linearly and a direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be parallel.

6. The fuel cell separator laminate according to claim 5, wherein the third receiving portion and the fourth receiving portion are formed to be mirror-symmetrical with respect to the second contact surface.

7. The first separator has a first bead portion protruding toward the first outer surface side opposite to the first contact surface, and a first receiving portion protruding linearly in the same direction as the first bead portion for receiving the over-compression load of the first bead portion. The fuel cell separator laminate according to claim 2, wherein a direction in which the first receiving portion of the first separator extends linearly and a direction in which the second receiving portion of the second separator extends linearly are configured to be non-parallel.

8. The fuel cell separator laminate according to claim 7, wherein a direction in which the first receiving portion of the first separator extends linearly and a direction in which the third receiving portion of the third separator extends linearly are configured to be parallel.

9. The fourth separator has a fourth bead portion protruding toward the fourth outer surface side opposite to the second contact surface, and a fourth receiving portion protruding linearly in the same direction as the fourth bead portion for receiving the over-compression load of the fourth bead portion. The fuel cell separator laminate according to claim 2, wherein a direction in which the third receiving portion of the third separator extends linearly and a direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be non-parallel.

10. The fuel cell separator laminate according to claim 9, wherein a direction in which the second receiving portion of the second separator extends linearly and a direction in which the fourth receiving portion of the fourth separator extends linearly are configured to be parallel.

11. The fuel cell separator laminate according to any one of claims 1 to 10, wherein two linearly extending directions of the opposing receiving portions are configured to form an angle of 5 to 90°.

12. In the one separator of the first set and / or the other separator of the second set, the fuel cell separator laminate according to any one of claims 1 to 10, wherein a protruding height of the receiving portion is smaller than a protruding height of the bead portion.

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