Fuel cell

Abstract

To provide a technique which can suppress deformation of a separator or a membrane-electrode gas diffusion layer assembly (MEGA) caused by hot-press processing.SOLUTION: A fuel battery cell comprises: a membrane-electrode gas diffusion layer assembly (MEGA); a separator facing a surface of the MEGA; and a seal body which is disposed along a peripheral edge of the surface of the MEGA so as to seal between the MEGA and the separator. The seal body has a first tape material and a second tape material which are disposed along the peripheral edge of the surface of the MEGA. An overlapping part is formed by an end of the first tape material and an end of the second tape material which overlap each other. At a position facing the overlapping part, the separator has a first bulging part which bulges in a direction away from the surface of the MEGA.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The technology disclosed in this specification relates to a fuel cell. [Background technology]

[0002] Patent Document 1 discloses a fuel cell. The fuel cell includes a membrane electrode gas diffusion layer assembly (MEGA), a separator facing the surface of the MEGA, and a thermoplastic adhesive that seals the gap between the MEGA and the separator. The thermoplastic adhesive has a frame shape that extends around the entire periphery of the surface of the MEGA. The thermoplastic adhesive melts during a hot press process and then hardens to produce a fuel cell. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-168370 A Summary of the Invention [Problem to be solved by the invention]

[0004] The thermoplastic adhesive as described above is produced by cutting out the center of a rectangular sheet, which is inefficient to produce, and therefore multiple tape-shaped materials are sometimes placed around the periphery of the surface of the MEGA.

[0005] When tape materials are used, the ends of the tape materials are overlapped so that no gaps are generated between the multiple tape materials. When a hot press process is performed in this state, the pressure acting on the overlapping portion of the multiple tape materials becomes higher than the pressure acting on the non-overlapping portion of the multiple tape materials. This may cause the separator or MEGA to deform due to stress concentration. This specification discloses a technology that can suppress the separator or MEGA from deforming due to the hot press process. [Means for solving the problem]

[0006] The fuel cell disclosed in this specification comprises a membrane electrode gas diffusion layer assembly (MEGA), a separator facing the surface of the MEGA, and a seal body arranged along the periphery of the surface of the MEGA to seal between the MEGA and the separator. The seal body comprises a first tape material and a second tape material arranged along the periphery of the surface of the MEGA. An overlapping portion is formed by overlapping an end of the first tape material and an end of the second tape material. The separator comprises a first bulging portion at a position facing the overlapping portion, which bulges in a direction away from the surface of the MEGA.

[0007] In the above configuration, since the first bulge is located at a position opposite to the overlapping portion and is separated from the surface of the MEGA, it is possible to prevent high pressure from acting on the overlapping portion even when hot pressing is performed. This prevents localized stress concentration in the separator and MEGA, and prevents the separator and MEGA from being deformed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a top view of a fuel cell according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view of a fuel cell according to an embodiment of the present invention. [Diagram 3] 4 is an enlarged top view of the vicinity of a first bulge portion of the fuel cell according to the embodiment. FIG. [Figure 4] 4A to 4C are diagrams illustrating a method for manufacturing a fuel cell according to an embodiment of the present invention.

[0009] In one embodiment of the present technology, at least a portion of the first bulge portion may be spaced apart from the overlap portion.

[0010] In the above-mentioned configuration, even if a hot press process is performed, it is possible to further suppress the application of high pressure to the overlapping portion, thereby preventing localized stress concentration in the separator and MEGA, and further suppressing deformation of the separator and MEGA.

[0011] In one embodiment of the present technology, the entire first bulge portion may be spaced apart from the overlap portion.

[0012] In the above-mentioned configuration, even if a hot press process is performed, it is possible to prevent high pressure from acting on the entire overlap portion, which prevents localized stress concentration on the separator and MEGA, and further prevents the separator and MEGA from being deformed.

[0013] In one embodiment of the present technology, the surface of the MEGA may have a rectangular shape having a long side and a short side. The separator may be configured to guide a coolant for cooling the MEGA in a direction parallel to the long side. The first tape material may be arranged along the long side. The second tape material may be arranged along the short side. In the overlapping portion, a tip portion at an end of the first tape material may overlap a side portion at an end of the second tape material. The first bulge portion of the separator may have a bead shape extending in a direction intersecting with the long side.

[0014] Generally, the area facing the seal body in the MEGA (the periphery of the surface of the MEGA) is a non-power generation area, and the area not facing the seal body in the MEGA (the area surrounded by the non-power generation area) is a power generation area. The coolant flows on the separator in a first direction along the long side of the surface of the MEGA. In order to increase the cooling efficiency of the power generation area, it is necessary for the coolant to flow over the power generation area. In the above configuration, the first bulge is disposed in a range facing the periphery of the surface of the MEGA and extends in a direction intersecting with the long side of the surface of the MEGA, so that the coolant does not easily flow over the first bulge in the first direction over the periphery of the surface of the MEGA. This allows the coolant to flow over the power generation area, thereby increasing the cooling efficiency of the power generation area.

[0015] In one embodiment of the present technology, the separator may further include a plurality of second bulging portions in a range facing the first tape material, the second bulging portions being arranged in a direction parallel to the long side together with the first bulging portion, and each of the second bulging portions may have a bead shape extending in a direction intersecting with the long side.

[0016] In the above configuration, the coolant is less likely to flow over the first bulge and the second bulges in the first direction along the periphery of the surface of the MEGA, which allows the coolant to flow over the power generation region, thereby further increasing the cooling efficiency of the power generation region.

[0017] (Example) A fuel cell 10 will be described with reference to the drawings. The fuel cell 10 shown in Fig. 1 is, for example, a polymer electrolyte fuel cell. A fuel cell stack in which multiple fuel cells 10 are stacked is mounted on a fuel cell vehicle such as an automobile or bus.

[0018] The fuel cell 10 includes a membrane electrode gas diffusion layer assembly 12, two seal bodies 14, and two separators 16. In Fig. 1, the separators 16 are shown by dashed lines. The two separators 16 sandwich the membrane electrode gas diffusion layer assembly 12 via the two seal bodies 14. Hereinafter, the membrane electrode gas diffusion layer assembly 12 will be referred to as a MEGA (Membrane-Electrode-Gas-diffusion-layer-Assembly) 12.

[0019] The MEGA12 is a layer structure in which an anode electrode and a cathode electrode sandwich a solid polymer electrolyte membrane. Detailed configurations of the anode electrode, the cathode electrode, and the solid polymer electrolyte membrane are widely known, so the description of those configurations will be omitted below. The surface 12a of the MEGA12 has a rectangular shape with long sides 18 and short sides 20. Hereinafter, the direction along the long sides 18 may be referred to as a first direction D1, and the direction along the short sides 20 may be referred to as a second direction D2. The MEGA12 includes a power generation region 22 and a non-power generation region 24. When the MEGA12 is viewed in a direction perpendicular to the surface 12a of the MEGA12, the power generation region 22 is located in the center of the MEGA12. Hereinafter, the direction perpendicular to surface 12a of MEGA12 and moving away from surface 12a of MEGA12 may be referred to as third direction D3 (see FIG. 2), and the direction perpendicular to surface 12a of MEGA12 and moving toward MEGA12a may be referred to as fourth direction D4 (see FIG. 2). Power generating region 22 generates electricity by allowing gas, for example, hydrogen gas and air, to flow within power generating region 22. When MEGA12 is viewed in fourth direction D4, non-power generating region 24 surrounds power generating region 22. Non-power generating region 24 is located in a region facing the periphery of surface 12a of MEGA12.

[0020] The seal body 14 is made of a thermoplastic resin material. The seal body 14 seals between the MEGA 12 and the separator 16. The seal body 14 is disposed along the periphery of the surface 12a of the MEGA 12. The seal body 14 is disposed on a non-power generation region 24 of the MEGA 12. In other words, the seal body 14 is disposed in a region facing the periphery of the surface 12a of the MEGA 12.

[0021] The seal body 14 includes two first tape materials 28 and two second tape materials 30. The first tape materials 28 are arranged on the periphery of the surface 12a of the MEGA 12 so as to extend in a first direction D1 along the long side 18. The length of the first tape material 28 in the first direction D1 is shorter than the length of the long side 18 of the surface 12a of the MEGA 12. The second tape material 30 is arranged on the periphery of the surface 12a of the MEGA 12 so as to extend in a second direction D2 along the short side 20. The length of the second tape material 30 in the second direction D2 is approximately the same as the length of the short side 20 of the surface 12a of the MEGA 12. The second tape material 30 is approximately perpendicular to the first tape material 28. The tip portion 28a of the end of the first tape material 28 rides up from the side onto the side portion 30a of the end of the second tape material 30, thereby overlapping with the side portion 30a of the end of the second tape material 30. As a result, four overlapping portions 32 are formed in the seal body 14.

[0022] The four overlapping portions 32 are disposed near the corners of the surface 12a of the MEGA 12. As shown in FIG. 2, in a direction perpendicular to the surface 12a of the MEGA 12, the thickness T1 of the overlapping portion 32 is substantially equal to the sum of the thickness of the first tape material 28 and the thickness of the second tape material 30. As shown in FIG. 3, the overlapping portion 32 has an elongated shape extending in the second direction D2. In FIG. 3, the overlapping portion 32 is illustrated by dot hatching. When the overlapping portion 32 is viewed in the fourth direction D4, the overlapping portion 32 has a rectangular shape. The long side 34 of the overlapping portion 32 extends in the second direction D2, and the short side 36 of the overlapping portion 32 extends in the first direction D1.

[0023] The separator 16 shown in FIG. 1 sandwiches the seal body 14 between itself and the surface 12a of the MEGA 12. The separator 16 is made of, for example, a metal material. The separator 16 includes a base 40, four first bulges 42, and a plurality of (ten in this embodiment) second bulges 44. The base 40 has a flat plate shape. The entire base 40 faces the surface 12a of the MEGA 12.

[0024] The first bulge portions 42 are formed on the base portion 40. The number of the first bulge portions 42 is the same as the number of the overlap portions 32. The first bulge portions 42 are disposed at positions facing the overlap portions 32, i.e., on the periphery of the surface 12a of the MEGA 12. The second bulge portions 44 are disposed at positions facing the first tape material 28, i.e., on the periphery of the surface 12a of the MEGA 12. The five second bulge portions 44 are disposed in line with the two first bulge portions 42 in the first direction D1 along the long side 18 of the surface 12a of the MEGA 12. The five second bulge portions 44 are disposed between the two first bulge portions 42.

[0025] 2, the first bulge portion 42 and the second bulge portion 44 bulge in the third direction D3 from the base portion 40. The first bulge portion 42 and the second bulge portion 44 are spaced apart from both the first tape material 28 and the second tape material 30.

[0026] The first bulge 42 includes a first inclined portion 46 and a first apex 48. The first inclined portion 46 connects the base 40 and the first apex 48. The first inclined portion 46 gradually moves away from the surface 12a of the MEGA 12 in the third direction D3 as it moves from the base 40 to the first apex 48. The entire first inclined portion 46 is spaced apart from the overlapping portion 32. The first apex 48 is the furthest from the surface 12a of the MEGA 12 in the first bulge 42. The first apex 48 is disposed in a region facing the overlapping portion 32. The width W1 from the surface 12a of the MEGA 12 to the first apex 48 is longer than the thickness T1 of the overlapping portion 32. The entire first apex 48 is spaced apart from the overlapping portion 32.

[0027] As shown in FIG. 3, the first bulge 42 has an elongated shape (bead shape) extending in the second direction D2. When the first bulge 42 is viewed in the fourth direction D4, the first bulge 42 has a rectangular shape, and the corners of the rectangle are rounded. In a modified example, the first bulge 42 may have a shape other than a rectangular shape, for example, an elliptical shape or a perfect circle shape. The major axis 50 of the first bulge 42 extends in the second direction D2, and the minor axis 52 of the first bulge 42 extends in the first direction D1. The length L1 of the first bulge 42 in the second direction D2 is longer than the length L2 of the long side 34 of the overlap portion 32. In addition, the length L3 of the first bulge 42 in the first direction D1 is longer than the length L4 of the short side 36 of the overlap portion 32.

[0028] As shown in FIG. 2, the second bulge 44 includes a second inclined portion 56 and a second apex 58. The second inclined portion 56 connects the base 40 and the second apex 58. The second inclined portion 56 gradually moves away from the surface 12a of the MEGA 12 in the third direction D3 as it moves from the base 40 toward the second apex 58. The second apex 58 is the furthest from the surface 12a of the MEGA 12 within the second bulge 44. A width W2 from the surface 12a of the MEGA 12 to the second apex 58 is substantially the same as a width W1 from the surface 12a of the MEGA 12 to the first apex 48.

[0029] As shown in FIG. 3, the second bulge 44 has an elongated shape (bead shape) extending in the second direction D2. When the second bulge 44 is viewed in the fourth direction D4, the second bulge 44 has a rectangular shape, and the corners of the rectangle are rounded. In a modified example, the second bulge 44 may have a shape other than a rectangular shape, for example, an elliptical shape or a perfect circle shape. The major axis 60 of the second bulge 44 extends in the second direction D2, and the minor axis 62 of the second bulge 44 extends in the first direction D1. The length L5 of the second bulge 44 in the second direction D2 is approximately the same as the length L1 of the first bulge 42 in the second direction D2. The length L6 of the second bulge 44 in the first direction D1 is shorter than the length L3 of the first bulge 42 in the first direction D1.

[0030] As shown in FIG. 2, a cooling flow passage 66 is formed on the separator 16. A coolant flows in the cooling flow passage 66. The coolant is, for example, cooling water. The coolant flows in the first direction D1 in the cooling flow passage 66 by being guided by the separator 16. The cooling flow passage 66 is narrowed in the third direction D3 in the region where the first bulge portion 42 and the second bulge portion 44 are located. This makes it difficult for the coolant to flow in the first direction D1 over the first bulge portion 42 and the second bulge portion 44. That is, the coolant does not easily flow in the first direction D1 on the periphery of the surface 12a of the MEGA 12. Therefore, the coolant flows in the first direction D1 on the power generation region 22 (see FIG. 1). This increases the cooling efficiency of the power generation region 22 by the coolant.

[0031] Next, a manufacturing method of the fuel cell 10 will be described. As shown in FIG. 4(a), the second tape material 30 is attached to the periphery of the surface 12a of the MEGA 12 in the second direction D2. Next, as shown in FIG. 4(b), the tip portion 28a of one end of the first tape material 28 is attached so as to ride up onto the side portion 30a of the end of one of the second tape materials 30. Next, the first tape material 28 is attached to the periphery of the surface 12a of the MEGA 12 in the first direction D1. Next, the tip portion 28a of the other end of the first tape material 28 is attached so as to ride up onto the side portion 30a of the end of the other second tape material 30 from the side. By attaching the first tape material 28, the overlap portion 32 is formed. Next, as shown in FIG. 1, the separator 16 is placed on the surface 12a of the MEGA 12 so that the first bulge portion 42 faces the overlap portion 32. As a result, the first tape material 28 and the second tape material 30 are sandwiched between the surface 12a of the MEGA 12 and the separator 16. Finally, the separator 16 is subjected to a hot press process by heat treating it while being pressed in the fourth direction D4. As a result, the first tape material 28 and the second tape material 30 melt and seal the gap between the surface 12a of the MEGA 12 and the separator 16. Thereafter, the melted first tape material 28 and second tape material 30 harden, and the fuel cell 10 is manufactured.

[0032] (effect) The fuel cell 10 of this embodiment includes a membrane electrode gas diffusion layer assembly 12 (MEGA 12), a separator 16 facing the surface 12a of the MEGA 12, and a seal body 14 arranged along the periphery of the surface 12a of the MEGA 12 to seal between the MEGA 12 and the separator 16. The seal body 14 includes a first tape material 28 and a second tape material 30 arranged along the periphery of the surface 12a of the MEGA 12. An overlapping portion 32 is formed by overlapping an end of the first tape material 28 and an end of the second tape material 30. The separator 16 includes a first bulging portion 42 at a position facing the overlapping portion 32, which bulges in a direction away from the surface 12a of the MEGA 12.

[0033] In the above configuration, the first bulge 42 is separated from the surface 12a of the MEGA 12 at a position opposite the overlap portion 32, so that even if a hot press process is performed, it is possible to prevent high pressure from acting on the overlap portion 32. This prevents localized stress concentration from occurring in the separator 16 or MEGA 12, and prevents the separator 16 or MEGA 12 from being deformed.

[0034] Furthermore, at least a portion of the first bulge 42 is spaced apart from the overlap portion 32 .

[0035] In the above-described configuration, even if a hot press process is performed, it is possible to further suppress the application of high pressure to the overlap portion 32. As a result, local stress concentration does not occur in the separator 16 or MEGA 12, and deformation of the separator 16 or MEGA 12 can be further suppressed.

[0036] Further, the entire first bulging portion 42 is spaced apart from the overlap portion 32 .

[0037] In the above-described configuration, even if a hot press process is performed, it is possible to prevent a high pressure from acting on the entire overlap portion 32. This prevents local stress concentration from occurring in the separator 16 or MEGA 12, and makes it possible to further prevent the separator 16 or MEGA 12 from being deformed.

[0038] Moreover, the surface 12a of the MEGA 12 has a rectangular shape having a long side 18 and a short side 29. The separator 16 is configured to guide the coolant that cools the MEGA 12 in a direction parallel to the long side 18. The first tape material 28 is arranged along the long side 18. The second tape material 30 is arranged along the short side 20. In the overlapping portion 32, the tip portion 28a at the end of the first tape material 28 overlaps with the side portion 30a at the end of the second tape material 30. The first bulging portion 42 of the separator 16 has a bead shape extending in a direction intersecting with the long side 18.

[0039] In general, the area facing the seal body 14 in the MEGA 12 (the periphery of the surface 12a of the MEGA 12) is the non-power generation area 24, and the area not facing the seal body 14 in the MEGA 12 (the area surrounded by the non-power generation area 24) is the power generation area 22. The coolant flows on the separator 16 in a first direction D1 along the long side 18 of the surface 12a of the MEGA 12. In order to improve the cooling efficiency of the power generation area 22, it is necessary for the coolant to flow on the power generation area 22. In the above configuration, the first bulge 42 is disposed in a range facing the periphery of the surface 12a of the MEGA 12 and extends in a direction intersecting with the long side 18 of the surface 12a of the MEGA 12, so that the coolant does not easily flow over the first bulge 42 and on the periphery of the surface 12a of the MEGA 12 in the first direction D1. This allows the coolant to flow on the power generation area 22, improving the cooling efficiency of the power generation area 22.

[0040] The separator 16 further includes a plurality of second bulging portions 44 that bulge in a direction away from the surface 12a of the MEGA 12 in a range facing the first tape material 28. The second bulging portions 44 are arranged in a line together with the first bulging portions 42 in a direction parallel to the long side 18, and each has a bead shape that extends in a direction intersecting with the long side 18.

[0041] In the above configuration, the coolant is unlikely to flow in the first direction D1 over the periphery of the surface 12a of the MEGA 12 by climbing over the first bulge 42 and the multiple second bulges 44. This allows the coolant to flow over the power generation region 22, thereby further improving the cooling efficiency of the power generation region 22.

[0042] The technical elements described in this specification or drawings have technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0043] 10: Fuel cell 12: Membrane electrode gas diffusion layer assembly 12a: Surface 14: Seal body 16: Separator 18: Long side 20: Short side 22: Power generation area 24: Non-power generation area 28: First tape material 28a:Tip part 30: Second tape material 30a: Lateral part 32: Overlapped section 34: Long side 36: Short side 40: Base 42:First bulge 44:Second bulge 46: 1st slope part 48: Top 1 50: Long axis 52: Short axis 56: Second inclined portion 58: Top 2 60: Long axis 62: Short axis 66: Cooling flow path D1 : Direction 1 D2: Direction 2 D3: 3rd direction D4 : Direction 4 T1: thick W1: Width W2:width L1, L2, L3, L4, L5, L6: Distance

Claims

1. a membrane electrode gas diffusion layer assembly (MEGA); a separator facing a surface of the MEGA; a seal disposed along the periphery of the surface of the MEGA to seal between the MEGA and the separator; the seal body includes a first tape material and a second tape material disposed along a periphery of the surface of the MEGA; an overlapping portion is formed by overlapping an end portion of the first tape material and an end portion of the second tape material, The separator includes a first bulge portion that bulges in a direction away from the surface of the MEGA at a position opposite to the overlap portion. Fuel cell.

2. The fuel cell according to claim 1 , wherein at least a portion of the first bulge portion is spaced apart from the overlap portion.

3. The fuel cell according to claim 2 , wherein the entire first bulge portion is spaced apart from the overlap portion.

4. The surface of the MEGA has a rectangular shape having a long side and a short side, The separator is configured to guide a coolant that cools the MEGA in a direction parallel to the long side, The first tape material is disposed along the long side, and the second tape material is disposed along the short side, In the overlapping portion, a tip portion of the end portion of the first tape material overlaps a side portion of the end portion of the second tape material, The fuel cell according to claim 3 , wherein the first bulge of the separator has a bead shape extending in a direction intersecting with the long side.

5. the separator further includes a plurality of second bulging portions that bulge in a direction away from the surface of the MEGA in a range facing the first tape material, The second bulging portions are arranged in a line with the first bulging portions in a direction parallel to the long side, and each of the second bulging portions has a bead shape extending in a direction intersecting the long side. The fuel cell according to claim 4 .

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