Fuel battery cell

Abstract

To suppress bending of an insulating member because the insulation between the separators may not be ensured and misalignment may occur between the layers when the insulating member is bent due to an external force.SOLUTION: A fuel battery cell includes a membrane electrode-gas diffusion layer assembly, a frame-shaped insulating member in contact with the outer periphery of the membrane electrode-gas diffusion layer assembly, and a pair of separators that sandwich the membrane electrode-gas diffusion layer assembly and the insulating member. The separator and the insulating member have protrusions on their outer peripheries within a range where their surfaces contact each other, protruding in a direction perpendicular to the surfaces of the area.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] The fuel cell comprises a membrane electrode gas diffusion layer assembly, a frame-shaped insulating member abutting 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 insulating member (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-198200 Summary of the Invention [Problem to be solved by the invention]

[0004] Sheet-shaped insulating members serve to insulate between separators and to position each layer that constitutes a fuel cell. If the insulating member is bent due to an external force, the insulating properties may be lost or misalignment may occur between layers. This specification presents techniques that are useful for solving these problems. [Means for solving the problem]

[0005] This specification discloses a fuel cell comprising a membrane electrode-gas diffusion layer assembly, a frame-shaped insulating member abutting against 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 insulating member, wherein the separator and the insulating member have protrusions on their outer peripheries within a range where their surfaces contact each other, protruding in a direction perpendicular to the surfaces of the area.

[0006] According to the above configuration, the separator and the insulating member have a convex portion on the outer periphery within the area where their surfaces contact each other, which creates a convex shape in the insulating member at a portion located outside the outer periphery, thereby increasing the strength of the insulating member and making it less likely to bend even when subjected to external force. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. [Figure 2] Cross-sectional view taken along line II-II in Figure 1. [Figure 3] FIG. 2 is a cross-sectional view of the outer periphery of a three-layer structure consisting of a frame and a pair of separators. [Figure 4] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present embodiment will be described with reference to the drawings. Each drawing is merely an example, and the present embodiment is not limited to the contents shown in the drawings. Furthermore, since each drawing is an example, the shapes shown in the drawings may not necessarily be accurate, and some parts may be omitted.

[0009] FIG. 1 shows an exploded perspective view of a fuel cell 2 in this embodiment. A fuel cell stack is formed by stacking a plurality of fuel cell cells 2. One fuel cell 2 is also called a single cell 2. A general explanation of fuel cells and fuel cell stacks can be found in known technologies such as Patent Document 1, so a brief explanation will be given here.

[0010] 1 shows the mutually perpendicular X, Y, and Z directions. The X and Y directions correspond to the short and long sides of the fuel cell 2, which is formed in a substantially rectangular shape. The Z direction corresponds to the direction in which multiple fuel cell units 2 are stacked.

[0011] The fuel cell 2 is a polymer electrolyte fuel cell that generates electricity by receiving a supply of anode gas (e.g., hydrogen) and cathode gas (e.g., oxygen). The fuel cell 2 includes a membrane electrode gas diffusion layer assembly 10, a frame-shaped insulating member 50, and a pair of separators 20, 40. The membrane electrode gas diffusion layer assembly 10 is abbreviated as MEGA10. The frame-shaped insulating member 50 is also called a frame 50. The separator 20 is also called an anode separator 20, and the separator 40 is also called a cathode separator 40.

[0012] The MEGA 10 includes a membrane electrode assembly (MEA) configured by bonding an anode electrode catalyst layer and a cathode electrode catalyst layer to either side of an electrolyte membrane, and two gas diffusion layers bonded to either side of the MEGA 10. The frame 50 is, for example, a resin sheet, and the inner peripheral portion of the frame abuts against the outer peripheral portion of the MEGA 10. The separator 20 is disposed on the negative side of the MEGA 10 and the frame 50 in the Z direction, and the separator 40 is disposed on the positive side of the MEGA 10 and the frame 50 in the Z direction, with the MEGA 10 and the frame 50 sandwiched between the separator 20 and the separator 40.

[0013] The separators 20, 40 and the frame 50 have holes a1 to a6 formed therethrough in the Z direction. These holes a1 to a6 define inlet manifolds and outlet manifolds for various fluids, such as anode gas, cathode gas, and cooling medium. These various fluids flow through flow paths formed in the separators 20, 40 that communicate between the corresponding inlet manifolds and outlet manifolds.

[0014] FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1 . The frame 50 has a region where the surfaces of the separators 20 and 40 contact each other, although not over the entire area where the frame 50 faces the separators 20 and 40. As shown in FIG. 2 , the outer peripheral edge 21 of the separator 20 and its surrounding area are spaced from the frame 50 toward the negative side in the Z direction. The outer peripheral edge 41 of the separator 40 and its surrounding area are spaced from the frame 50 toward the positive side in the Z direction. However, the separators 20 and 40 contact the frame 50 inside the outer peripheral edges 21 and 41 and their surrounding areas. In this embodiment, the outer peripheral portion 30 within the area where the frame 50 and the separators 20 and 40 contact each other has a protrusion 31 that protrudes perpendicularly to the surface of the region, as shown in FIG. 3 . The outer peripheral edge 51 of the frame 50 extends outward beyond the outer peripheral edges 21 and 41 of the separators 20 and 40. FIG. 2 and FIG. 4, which will be described later, illustrate the approximate range of the outer periphery 30.

[0015] 3 shows a cross section of the outer peripheral portion 30 in a three-layer structure consisting of a frame 50 and a pair of separators 20, 40, viewed from the Y direction. According to FIG. 3, the outer peripheral portion 30 has a protrusion 31 that protrudes toward the +Z direction, which is perpendicular to the XY plane. By forming the protrusion 31 in the portion of each of the separators 20, 40 that corresponds to the outer peripheral portion 30, the frame 50 that is sandwiched between the separators 20, 40 also has a protrusion 31. While at least one protrusion 31 is sufficient, in the example of FIG. 3, the protrusions 31 are repeatedly formed along the outer peripheral portion 30, i.e., along the X direction.

[0016] When a plurality of convex portions 31 are repeatedly formed as in Fig. 3, it can be understood that concave portions are formed between the convex portions 31. Therefore, according to Fig. 3, it can also be said that an uneven shape is repeatedly formed along the outer periphery 30. The convex portions 31 or uneven shape in the outer periphery 30 may be, for example, a trapezoidal shape, a rectangular shape, a triangular wave shape, or the like, in addition to the curved shape as in Fig. 3.

[0017] FIG. 4 shows a simplified perspective view of separator 40 and frame 50 as viewed from the +Z direction side. As described with reference to FIG. 3, convex portions 31 are formed on outer peripheral portion 30 within the area where frame 50 and separators 20, 40 contact each other. Therefore, the portion of frame 50 outside outer peripheral portion 30, including outer peripheral end 51, is influenced by convex portions 31 and has a convex shape substantially similar to that of convex portions 31. When multiple convex portions 31 are repeatedly formed on outer peripheral portion 30 as shown in FIG. 3, the portion of frame 50 outside outer peripheral portion 30, including outer peripheral end 51, also has a shape having multiple convex portions repeatedly, as shown in FIG.

[0018] According to this embodiment, the fuel cell 2 includes the MEGA 10, a frame-shaped frame 50 abutting the outer periphery of the MEGA 10, and a pair of separators 20, 40 sandwiching the MEGA 10 and the frame 50. The separators 20, 40 and the frame 50 have protrusions 31 on the outer periphery 30 within the area where their surfaces contact each other, protruding in a direction perpendicular to the surface of that area. According to this configuration, the protrusions 31 formed on the outer periphery 30 also create a similar protruding shape in the portion of the frame 50 located outside the outer periphery 30, thereby increasing the strength of the frame 50. Therefore, even if the outer periphery 51 of the frame 50 is subjected to an external force, the frame 50 is less likely to bend than conventional structures. As a result, insulation between the separators 20, 40 is ensured and misalignment between the layers is suppressed.

[0019] According to the explanation based on the drawings so far, a configuration has been disclosed in which the outer periphery 30 along one of the four sides of the rectangular fuel cell 2 in the XY plane has a protrusion 31. However, it goes without saying that the fuel cell 2 may have a configuration in which one or more protrusions 31 are provided on the outer periphery 30 along all four sides or each of two or more sides.

[0020] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Furthermore, the technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of those objectives itself has technical utility. [Explanation of symbols]

[0021] 2: fuel cell, 10: membrane electrode gas diffusion layer assembly (MEGA), 20: separator, 30: outer periphery, 31: protrusion, 40: separator, 50: insulating member (frame), 51: outer periphery

Claims

[Claim 1] a membrane electrode gas diffusion layer assembly; a frame-shaped insulating member in contact with the outer periphery of the membrane electrode gas diffusion layer assembly; a pair of separators sandwiching the membrane electrode gas diffusion layer assembly and the insulating member, The separator and the insulating member have a protrusion on the outer periphery within a range where their surfaces contact each other, the protrusion protruding in a direction perpendicular to the surface of the range.

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