Single cell of fuel battery

Abstract

To provide a single cell of a fuel battery capable of preventing a power generation unit from peeling from an adhesive.SOLUTION: A single cell 10 includes: a sheet-shaped power generation unit 20 including a membrane electrode assembly 21; and a frame member 30 that has an opening 31 for accommodating the power generation unit 20, and the outer periphery of the power generation unit 20 is bonded together with adhesive. The frame member 30 includes: a frame-shaped main body 33 surrounding the opening 31; a soft portion 35 that protrudes from the main body 33 toward the inner periphery of the main body 33 and is made of an elastic material softer than the main body 33; and a hard portion 37 that protrudes from the soft portion 35 toward the inner periphery and is made of a material harder than the soft portion 35. The outer periphery of the power generation unit 20 is bonded to the hard portion 37.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a single cell of a fuel cell. [Background technology]

[0002] The single cell of the fuel cell described in Patent Document 1 comprises a membrane electrode gas diffusion layer assembly, a frame surrounding the outer periphery of the membrane electrode gas diffusion layer assembly, and a pair of separators sandwiching the membrane electrode gas diffusion layer assembly and the frame.

[0003] The membrane electrode gas diffusion layer assembly includes a membrane electrode assembly, an anode-side gas diffusion layer, and a cathode-side gas diffusion layer that sandwich the membrane electrode assembly. The membrane electrode assembly has a protruding portion that protrudes outward beyond the cathode-side gas diffusion layer.

[0004] The frame has an opening for accommodating the membrane electrode gas diffusion layer assembly. The frame has an engagement portion that protrudes from the inner peripheral surface of the opening toward the inner peripheral side of the opening. The protrusion of the membrane electrode assembly is bonded to the engagement portion via an adhesive in the thickness direction of the membrane electrode assembly. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-215958 Summary of the Invention [Problem to be solved by the invention]

[0006] In the unit cell described in Patent Document 1, the membrane electrode assembly generates heat and cools as the fuel cell generates electricity, which causes repeated thermal deformation in the planar direction of the membrane electrode assembly, which may cause the membrane electrode assembly to peel off from the adhesive. [Means for solving the problem]

[0007] A single fuel cell cell for solving the above problem is a single fuel cell cell comprising: a sheet-shaped power generation section including a membrane electrode assembly; and a frame member having an opening for accommodating the power generation section, the frame member having an outer periphery of the power generation section bonded via an adhesive, the frame member having a frame-shaped main body surrounding the opening, a soft section protruding from the main body toward the inner periphery of the main body and formed of an elastic material softer than the main body, and a hard section protruding from the soft section toward the inner periphery and formed of a material harder than the soft section, and the outer periphery of the power generation section is bonded to the hard section.

[0008] According to the above configuration, a soft portion that is softer than the hard portion and the main body is provided between the hard portion to which the power generation unit is bonded and the main body, so that when the power generation unit is thermally deformed in the planar direction, the soft portion is likely to deform in response to the thermal deformation.

[0009] Furthermore, according to the above configuration, the hard portion is made of a material harder than the soft portion, and therefore, when the power generation portion is thermally deformed in the planar direction, the soft portion deforms preferentially over the hard portion, thereby suppressing relative movement between the power generation portion and the hard portion.

[0010] As a result, the power generating section can be prevented from peeling off from the adhesive. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an exploded perspective view of a single cell of a fuel cell according to one embodiment. [Figure 2] FIG. 2 is a plan view of the frame member of FIG. [Figure 3] FIG. 3 is a cross-sectional view of the single cell taken along line 3-3 in FIG. [Figure 4] FIG. 4 is a cross-sectional view of a modified single cell. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of a single cell of a fuel cell will be described below with reference to FIGS. (Schematic configuration of unit cell 10) The fuel cell is constructed by stacking a plurality of unit cells 10 shown in FIG. 1. The unit cell 10 includes a power generation section 20, a frame member 30, and a pair of separators 40. The power generation section 20 is sheet-shaped. The frame member 30 surrounds the power generation section 20. The pair of separators 40 sandwich the power generation section 20 and the frame member 30 from both sides in the thickness direction. One of the pair of separators 40 is an anode separator 40A that is overlaid on the anode side surface of the power generation section 20. The other of the pair of separators 40 is a cathode separator 40B that is overlaid on the cathode side surface of the power generation section 20.

[0013] The unit cell 10 has, for example, a rectangular shape having long and short sides in a plan view. Hereinafter, the long side direction and the short side direction of the unit cell 10 will be simply referred to as the long side direction and the short side direction, respectively.

[0014] The unit cell 10 has a plurality of manifolds 11A, 11B, 11C, 11D, 11E, and 11F that allow fluid to flow in the stacking direction of the unit cells 10. Each of the manifolds 11A, 11B, 11C, 11D, 11E, and 11F penetrates a pair of separators 40 and a frame member 30. Examples of fluids include reactive gases such as hydrogen gas and air, and cooling water.

[0015] At one end in the long side direction of the unit cell 10, manifolds 11A, 11F, and 11D are lined up in this order from one side in the short side direction. At the other end opposite to the one end in the long side direction of the unit cell 10, manifolds 11C, 11E, and 11B are lined up in this order from one side in the short side direction.

[0016] (Configuration of power generation unit 20) 1 and 3, the power generation section 20 includes a membrane electrode assembly 21, and an anode-side gas diffusion layer 22 and a cathode-side gas diffusion layer 23 that sandwich the membrane electrode assembly 21. Although not shown, the membrane electrode assembly 21 includes an electrolyte membrane, and an anode electrode catalyst layer and a cathode electrode catalyst layer that sandwich the electrolyte membrane. The anode-side gas diffusion layer 22 is overlaid on the anode electrode catalyst layer. The cathode-side gas diffusion layer 23 is overlaid on the cathode electrode catalyst layer.

[0017] The anode-side gas diffusion layer 22 is bonded to the entire surface of one side in the thickness direction of the membrane electrode assembly 21. The cathode-side gas diffusion layer 23 is bonded to the surface of the other side opposite to the one side in the thickness direction of the membrane electrode assembly 21. The cathode-side gas diffusion layer 23 is formed to be slightly smaller than the anode-side gas diffusion layer 22. Therefore, the outer periphery of the membrane electrode assembly 21 is exposed from the cathode-side gas diffusion layer 23.

[0018] (Configuration of frame member 30) 2, the frame member 30 has a rectangular frame shape. The frame member 30 has an opening 31 that houses the power generation unit 20. The opening 31 penetrates the center of the frame member 30 in the thickness direction. In a plan view, the opening 31 has a rectangular shape with long sides extending in the long-side direction.

[0019] The frame member 30 has through holes 32A, 32B, 32C, 32D, 32E, and 32F that form the manifolds 11A, 11B, 11C, 11D, 11E, and 11F. The through holes 32A, 32B, 32C, 32D, 32E, and 32F are provided around the opening 31.

[0020] The frame member 30 has a main body 33, a soft portion 35, and a hard portion 37. The soft portion 35 is made of an elastic material that is softer than the main body 33. The hard portion 37 is made of a material that is harder than the soft portion 35.

[0021] The main body 33 is in the shape of a frame surrounding the opening 31. The main body 33 has through holes 32A, 32B, 32C, 32D, 32E, and 32F. 3, the main body 33 is sandwiched between a pair of separators 40, and functions as a portion that bears the clamping load between the unit cells 10. The main body 33 and the pair of separators 40 are bonded together, for example, via an adhesive.

[0022] The main body 33 has a protruding portion 34 that protrudes toward the inner periphery of the main body 33. The protruding portion 34 is formed around the entire periphery of the frame member 30. The thickness of the protruding portion 34 is smaller than the thickness of the main body 33 excluding the protruding portion 34. One surface of the protruding portion 34 in the thickness direction is in contact with the cathode separator 40B. One surface of the protruding portion 34 in the thickness direction is flush with one surface of the main body 33 excluding the protruding portion 34 in the thickness direction. The protruding portion 34 has an inner circumferential surface 34a that is perpendicular to the surface direction of the power generation section 20. The inner circumferential surface of the main body 33 includes the inner circumferential surface 34a of the protruding portion 34.

[0023] The soft portion 35 protrudes from the main body 33 toward the inner periphery of the main body 33. More specifically, the soft portion 35 protrudes from the inner periphery 34a of the protruding portion 34 toward the inner periphery of the main body 33. The soft portion 35 is formed around the entire periphery of the frame member 30. The soft portion 35 has an inner periphery 35a that is perpendicular to the surface direction of the power generation section 20. The thickness of the soft portion 35 is the same as that of the protruding portion 34 around the entire periphery of the frame member 30. One surface of the soft portion 35 in the thickness direction is in contact with the cathode separator 40B.

[0024] The soft portion 35 has a flexible portion 36 that is configured to be expandable and contractible in the planar direction of the power generation section 20. The flexible portion 36 is formed in the soft portion 35 around the entire periphery of the frame member 30. The flexible portion 36 is curved in an arc shape that is convex toward the anode separator 40A in the thickness direction of the soft portion 35. The part of the soft portion 35 where the flexible portion 36 is formed includes an area that does not contact the cathode separator 40B.

[0025] The hard portion 37 protrudes from the soft portion 35 toward the inner periphery of the main body 33. More specifically, the hard portion 37 protrudes from the inner periphery 35a of the soft portion 35 toward the inner periphery of the main body 33. The hard portion 37 is formed around the entire periphery of the frame member 30. The hard portion 37 has an inner periphery 37a that is perpendicular to the surface direction of the power generation section 20. The hard portion 37 forms the inner periphery of the opening 31. The thickness of the hard portion 37 is the same as that of the protruding portion 34 around the entire periphery of the frame member 30. One surface of the hard portion 37 in the thickness direction is in contact with the cathode separator 40B.

[0026] The outer periphery of the power generation unit 20 is bonded to the hard portion 37. More specifically, the portion of the membrane electrode assembly 21 that is exposed from the cathode-side gas diffusion layer 23 is bonded to the hard portion 37 in the thickness direction via an adhesive. The membrane electrode assembly 21 is bonded only to the hard portion 37 of the frame member 30.

[0027] A gap S1 is provided around the entire periphery of the frame member 30 between the main body 33 and the power generation unit 20 in the surface direction of the power generation unit 20. A gap S2 is provided around the entire periphery of the frame member 30 between the hard portion 37 and the cathode-side gas diffusion layer 23 in the surface direction of the power generation unit 20.

[0028] The main body 33 is formed of a thermoplastic resin material such as polyphenylene sulfide (PPS), polyether ether ketone (PEEK), modified polyphenylene ether (modified PPE), etc. The soft portion 35 is formed of a thermoplastic resin material such as polypropylene (PP), polyethylene (PE), etc. The hard portion 37 is formed of the same resin material as the main body 33, for example.

[0029] The main body 33, the soft portion 35, and the hard portion 37 are integrally molded products made of two or more different resin materials. The frame member 30 is manufactured, for example, by two-color molding the main body 33 and the soft portion 35 to produce a primary molded product, and then two-color molding the primary molded product and the hard portion 37.

[0030] (Configuration of separator 40) The anode separator 40A and the cathode separator 40B have, for example, the same shape. The anode separator 40A and the cathode separator 40B sandwich the power generation section 20 and the frame member 30 in mutually inverted positions.

[0031] The anode separator 40A has through holes 41A, 41B, 41C, 41D, 41E, and 41F that form the manifolds 11A, 11B, 11C, 11D, 11E, and 11F. The cathode separator 40B has through holes 41D, 41C, 41B, 41A, 41E, and 41F that form the manifolds 11A, 11B, 11C, 11D, 11E, and 11F.

[0032] The separator 40 has a plurality of groove-shaped gas flow channels 42 that allow the reactant gas to flow in the surface direction of the separator 40. The gas flow channels 42 are formed on the surface of the separator 40 that faces the power generation section 20. The gas flow channels 42 of the anode separator 40A allow hydrogen gas supplied from the through-holes 41A to flow toward the through-holes 41B. The gas flow channels 42 of the cathode separator 40B allow air supplied from the through-holes 41B to flow toward the through-holes 41A.

[0033] The separator 40 has a plurality of groove-shaped cooling channels 43 that allow cooling water to flow in the surface direction of the separator 40. The cooling channels 43 are formed on the surface of the separator 40 opposite to the surface on which the gas channels 42 are formed. The cooling channels 43 allow cooling water supplied from the through-holes 41E to flow toward the through-holes 41F. The cooling water flows between the cooling channel 43 in the anode separator 40A of one unit cell 10 and the cooling channel 43 in the cathode separator 40B of the other unit cell 10 of two unit cells 10 adjacent to each other in the stacking direction.

[0034] The separator 40 is made of, for example, a metal material such as titanium or stainless steel, or a composite material containing a resin material and a conductive material. <Operation of this embodiment> A soft portion 35, which is softer than the hard portion 37 and the main body 33, is provided between the hard portion 37 to which the power generation unit 20 is bonded and the main body 33. Therefore, when the power generation unit 20 is thermally deformed in the planar direction, the soft portion 35 is likely to deform in response to the thermal deformation.

[0035] Furthermore, the hard portion 37 is formed of a material harder than the soft portion 35. Therefore, when the power generation unit 20 is thermally deformed in the planar direction, the soft portion 35 deforms preferentially over the hard portion 37, thereby suppressing relative movement between the power generation unit 20 and the hard portion 37.

[0036] <Effects of this embodiment> (1) The frame member 30 has a frame-shaped main body 33 surrounding the opening 31, a soft portion 35 protruding from the main body 33 toward the inner periphery of the main body 33, and a hard portion 37 protruding from the soft portion 35 toward the inner periphery. The outer periphery of the power generation unit 20 is bonded to the hard portion 37 via an adhesive.

[0037] According to the above configuration, the power generating section 20 can be prevented from peeling off from the adhesive. (2) The flexible section 35 has a flexible section 36 that is configured to be expandable and contractible in the planar direction of the power generation section 20 .

[0038] According to the above configuration, the flexible portion 36 is easily deformed in accordance with thermal deformation in the planar direction of the power generation portion 20. This makes it easier for the soft portion 35 to deform. (3) A gap S1 is provided between the main body 33 and the power generation section 20 in the plane direction of the power generation section 20.

[0039] According to the above configuration, when the power generating unit 20 thermally expands in the planar direction, the power generating unit 20 is less likely to come into contact with the main body 33 in the planar direction. This makes it possible to suppress the stress acting on the frame member 30 that would otherwise be caused by the power generating unit 20 coming into contact with the main body 33 during thermal expansion.

[0040] (4) The soft portion 35 and the hard portion 37 are formed around the entire periphery of the frame member 30 . According to the above configuration, peeling of the power generating section 20 from the adhesive can be prevented over the entire periphery of the frame member 30.

[0041] (5) The main body 33, the soft portion 35, and the hard portion 37 are integrally molded. According to the above configuration, the frame member 30 can be formed more easily than when the main body 33, the soft portion 35, and the hard portion 37 are formed separately and then bonded together.

[0042] (6) The main body 33 is sandwiched between a pair of separators 40 . According to the above configuration, the main body 33 of the frame member 30, which is sandwiched between the pair of separators 40, is formed of a material harder than the soft portion 35. Therefore, compared to when the entire main body 33 is formed of the same material as the soft portion 35, it is possible to prevent the main body 33 from becoming insufficiently rigid.

[0043] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0044] The soft portion 35 may be made of rubber instead of resin material, as long as the material is elastic. The hard portion 37 may be made of a material different from that of the main body 33. In this case, the hard portion 37 may be made of a material that is softer than that of the main body 33.

[0045] The main body 33, the soft portion 35, and the hard portion 37 may be bonded together with an adhesive. The soft portion 35 and the hard portion 37 may be provided only on a portion of the circumference of the frame member 30. In this case, it is preferable that the hard portion 37 and the protruding portion 34 are provided continuously in the circumference of the frame member 30, and the power generation unit 20 is bonded to both the hard portion 37 and the protruding portion 34.

[0046] The main body 33 and the power generation section 20 may be in contact with each other over part or the entire circumference of the frame member 30 . The flexible section 36 is not limited to being curved in an arc shape, as long as it is configured to be expandable and contractible in the planar direction of the power generation section 20. The flexible section 36 may be, for example, wavy.

[0047] The flexible section 35 does not have to have the flexible section 36. In this case, the flexible section 35 may extend in a planar shape in the surface direction of the power generation section 20. The power generation section 20 may be bonded to both the hard section 37 and the soft section 35. In this case, it is preferable that the power generation section 20 be bonded to the soft section 35 excluding the flexible section 36.

[0048] As shown in Fig. 4, the soft portion 35 may be formed thinner than the protruding portion 34 and the hard portion 37 of the main body 33. In this modified example, the soft portion 35 may further have a flexible portion 36. According to this modified example, the soft portion 35 is more likely to deform in response to thermal deformation in the planar direction of the power generation section 20. This makes the soft portion 35 more likely to deform.

[0049] <Additional Notes> The above embodiment includes the configurations described in the following supplementary notes. [Appendix 1] A unit cell of a fuel cell comprising: a sheet-like power generation section including a membrane electrode assembly; and a frame member having an opening for accommodating the power generation section, the frame member having an outer periphery of the power generation section bonded to the frame member via an adhesive, the frame member having a frame-shaped main body surrounding the opening; a soft section protruding from the main body toward the inner periphery of the main body and made of an elastic material softer than the main body; and a hard section protruding from the soft section toward the inner periphery and made of a material harder than the soft section, the unit cell of a fuel cell having an outer periphery of the power generation section bonded to the hard section.

[0050] [Appendix 2] The unit cell of the fuel cell according to [Appendix 1], wherein the soft portion has a flexible portion configured to be expandable and contractible in the planar direction of the power generation portion. [Appendix 3] A single cell of a fuel cell according to [Appendix 1] or [Appendix 2], wherein the soft portion is formed thinner than the main body and the hard portion.

[0051] [Appendix 4] A single cell of a fuel cell according to any one of [Appendix 1] to [Appendix 3], wherein a gap is provided between the main body and the power generation section in the planar direction of the power generation section. [Appendix 5] A single cell of a fuel cell according to any one of [Appendix 1] to [Appendix 4], wherein the soft portion and the hard portion are formed over the entire periphery of the frame member.

[0052] [Appendix 6] The unit cell of the fuel cell according to any one of [Appendix 1] to [Appendix 5], wherein the main body, the soft portion, and the hard portion are integrally molded. [Explanation of symbols]

[0053] S1, S2...Gap 10...Single cell 11A, 11B, 11C, 11D, 11E, 11F...Manifold 20...Power generation section 21...Membrane electrode assembly 22...Anode side gas diffusion layer 23...Cathode side gas diffusion layer 30...Frame member 31...Opening 32A, 32B, 32C, 32D, 32E, 32F...Through hole 33...Main body 34...Protruding part 34a…Inner peripheral surface 35…Soft part 35a...Inner peripheral surface 36...Flexure 37...Hard part 37a…Inner peripheral surface 40...Separator 40A...Anode separator 40B...Cathode separator 41A, 41B, 41C, 41D, 41E, 41F...Through hole 42...Gas flow path 43...Cooling channel

Claims

1. a sheet-like power generation unit including a membrane electrode assembly; a frame member having an opening for accommodating the power generation unit, the frame member having an outer periphery of the power generation unit bonded thereto via an adhesive, The frame member is a frame-shaped main body surrounding the opening; a soft portion that protrudes from the main body toward the inner periphery of the main body and is made of an elastic material that is softer than the main body; a hard portion protruding from the soft portion toward the inner periphery and formed of a material harder than the soft portion, an outer periphery of the power generating unit is bonded to the hard portion; A single fuel cell.

2. the soft section has a flexible section configured to be expandable and contractible in a planar direction of the power generation section; A single cell of the fuel cell according to claim 1 .

3. The soft portion is formed to be thinner than the main body and the hard portion. A single cell of the fuel cell according to claim 1 .

4. a gap is provided between the main body and the power generating unit in the surface direction of the power generating unit; A single cell of the fuel cell according to claim 1 .

5. The soft portion and the hard portion are formed over the entire periphery of the frame member. A single cell of the fuel cell according to claim 1 .

6. The main body, the soft portion, and the hard portion are integrally molded. A single fuel cell according to any one of claims 1 to 5.

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