JP6816620B2 - Fuel cell - Google Patents

Description

The present invention relates to a fuel cell.

Fuel cells with manifolds penetrating a plurality of single cells are known. In order to prevent the fluid flowing through the manifold from leaking to the outside, a seal portion is provided around the manifold to seal the fluid. For example, it is known that a fluid is sealed by providing the separator with a sealing portion formed of a hollow protruding portion located around the manifold (for example, Patent Document 1).

Special Table 2006-504872

A plurality of flow portions made of hollow protrusions are provided intersecting the seal portions made of hollow protrusions so that the fluid can flow between the manifold and the flow path provided inside the single cell. Can be considered. When joining a separator provided with such a seal portion and a distribution portion to the other separator or an insulating frame, the size of the distribution portion region provided with a plurality of distribution portions is sufficiently large on the side of the seal portion. It may not be joined due to strength. In this case, the seal linear pressure of the seal portion in the distribution portion region becomes low, and a seal defect may occur.

The present invention has been made in view of the above problems, and an object of the present invention is to suppress the occurrence of sealing defects.

The present invention comprises a single cell having a pair of separators and an insulating frame arranged side by side with the pair of separators in the stacking direction of the pair of separators and surrounding the membrane electrode gas diffusion layer junction. , The pair of separators and a manifold through which the fluid flows through the insulating frame, and one of the pairs of separators overlaps the manifold and the membrane electrode gas diffusion layer junction. A seal portion formed of a hollow first protruding portion extending at least between the flow paths arranged therein, and the manifold extending so as to intersect the seal portion and with respect to the manifold and the seal portion. Has a plurality of flow sections composed of hollow second protrusions for flowing the fluid to and from the opposite side, and the plurality of flow sections are two or more adjacent flow sections at a first interval. The distribution unit group consisting of the above is adjacent to each other at a second interval wider than the first interval , and the one separator is provided on both sides of the seal portion and the distribution other than the distribution unit region provided with the plurality of distribution units. in other separator or said bonded to the insulating frame, the fuel cell of the said pair of separators at both sides of the seal portion between the circulation unit groups adjacent in the second interval of the parts area is there.

According to the present invention, the occurrence of sealing defects can be suppressed.

FIG. 1A is an exploded plan view of a single cell constituting the fuel cell according to the first embodiment, and FIG. 1B is a sectional view of a membrane electrode gas diffusion layer joint. 2 (a) is an enlarged view of the region A of FIG. 1 (a), FIG. 2 (b) is a perspective view of the anode-side separator in the vicinity of the circulation portion of FIG. 2 (a), FIGS. 2 (c) and 2 (c). FIG. 2 (d) is a cross-sectional view between A and A in FIG. 2 (a). FIG. 3 is a plan view of a portion corresponding to the region A in FIG. 1A in the fuel cell according to the comparative example. FIG. 4A is a diagram for explaining the bonding between the anode side separator and the insulating frame in Comparative Example, and FIG. 4B is a diagram for explaining the bonding between the anode side separator and the insulating frame in Example 1. FIG. 5 (a) is a diagram illustrating a seal linear pressure test method, FIG. 5 (b) is a diagram showing a seal linear pressure test result in a comparative example, and FIG. 5 (c) is a seal in Example 1. It is a figure which shows the test result of the linear pressure. 6 (a) and 6 (b) are diagrams for explaining the reason why the seal linear pressure of the seal portion in the distribution portion region is improved. FIG. 7 is a perspective view of the single cell in the vicinity of the distribution section in the second embodiment.

Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1A is an exploded plan view of a single cell 10 constituting the fuel cell according to the first embodiment, and FIG. 1B is a cross-sectional view of a membrane electrode gas diffusion layer joint 20. In addition, in FIG. 1A, the illustration of the distribution section described later is omitted for the purpose of clarifying the figure. The fuel cell of Example 1 is a polymer electrolyte fuel cell that generates electricity by receiving a fuel gas (for example, hydrogen) and an oxidant gas (for example, air) as reaction gases, and is a stack in which a large number of single cells are stacked. Has a structure. The fuel cell of the first embodiment is mounted on, for example, a fuel cell vehicle or an electric vehicle.

As shown in FIG. 1A, the single cell 10 is an insulator that surrounds the anode side separator 22a, the cathode side separator 22c, the membrane electrode gas diffusion layer assembly (MEGA) 20, and MEGA 20. A frame 30 is provided. The MEGA 20 and the insulating frame 30 are sandwiched between the anode-side separator 22a and the cathode-side separator 22c. The anode-side separator 22a and the cathode-side separator 22c are formed of a member having gas blocking property and electron conductivity, and are formed of, for example, a metal member such as press-molded stainless steel. The insulating frame 30 is formed of an elastic member such as rubber or an elastomer resin (for example, a thermoplastic elastomer resin), but may be formed of an insulating member other than the elastic member.

The single cell 10 has a manifold that penetrates the anode side separator 22a, the insulating frame 30, and the cathode side separator 22c. The manifolds include a fuel gas supply manifold 32 and a fuel gas discharge manifold 34 for fuel gas, an oxidizer gas supply manifold 36 and an oxidizer gas discharge manifold 38 for oxidant gas, a refrigerant supply manifold 40 for refrigerant, and a refrigerant discharge. Includes a manifold 42 and.

On the surface of the anode-side separator 22a on the MEGA20 side, an anode gas flow path 24a through which the fuel gas supply manifold 32 and the fuel gas discharge manifold 34 are communicated is formed. On the surface of the cathode side separator 22c on the MEGA 20 side, a cathode gas flow path 24c is formed in which the oxidant gas supply manifold 36 and the oxidant gas discharge manifold 38 communicate with each other and the oxidant gas flows. On the surface of the anode side separator 22a opposite to MEGA 20 and the surface of the cathode side separator 22c opposite to MEGA 20, a refrigerant flow path 26 in which the refrigerant supply manifold 40 and the refrigerant discharge manifold 42 communicate with each other and the refrigerant flows flows. It is formed. The anode gas flow path 24a, the cathode gas flow path 24c, and the refrigerant flow path 26 are arranged so as to overlap the MEGA 20.

The anode-side separator 22a is provided with a seal portion 50 for suppressing the fluid flowing through the manifold from leaking to the outside. The seal portion 50 is provided so as to be located around the manifold by surrounding the manifold or enclosing the manifold and the flow path together.

As shown in FIG. 1B, the MEGA 20 is a film including an electrolyte film 14, an anode catalyst layer 16a provided on one surface of the electrolyte film 14, and a cathode catalyst layer 16c provided on the other surface. Includes Membrane Electrode Assembly (MEA) 12. The electrolyte membrane 14 is a solid polymer membrane formed of a fluororesin material or a carbon-based resin material having a sulfonic acid group, and has good proton conductivity in a wet state. The anode catalyst layer 16a and the cathode catalyst layer 16c are solid polymers having carbon particles (for example, carbon black) carrying a catalyst (for example, platinum or platinum-cobalt alloy) for advancing an electrochemical reaction and a sulfonic acid group. Includes ionomers, which have good proton conductivity in wet conditions.

A pair of gas diffusion layers (anode gas diffusion layer 18a and cathode gas diffusion layer 18c) are arranged on both sides of the MEA 12. MEGA20 is formed by MEA12 and a pair of gas diffusion layers. The anode gas diffusion layer 18a and the cathode gas diffusion layer 18c are formed of a member having gas permeability and electron conductivity, and are formed of a porous carbon member such as carbon cloth or carbon paper.

2 (a) is an enlarged view of the region A of FIG. 1 (a), FIG. 2 (b) is a perspective view of the anode side separator 22a in the vicinity of the distribution section 52 of FIG. 2 (a), and FIG. 2 (c). ) And FIG. 2 (d) are cross-sectional views between A and A in FIG. 2 (a). FIG. 2C shows a cross section before the plurality of single cells are laminated, and FIG. 2D shows a cross section after the plurality of single cells are laminated. The structure described below is provided around any of the fuel gas supply manifold 32, the fuel gas discharge manifold 34, the oxidant gas supply manifold 36, the oxidant gas discharge manifold 38, the refrigerant supply manifold 40, and the refrigerant discharge manifold 42. Can also be applied.

As shown in FIGS. 2 (a) and 2 (b), the anode-side separator 22a is provided with respect to the seal portion 50 that seals the fluid flowing through the manifold so as not to leak to the outside of the fuel cell, and the manifold and the seal portion 50. It also has a plurality of flow sections 52 for flowing a fluid to and from the side opposite to the manifold. The distribution unit 52 intersects the seal unit 50 and extends.

The seal portion 50 is formed of a hollow protruding portion so as to exert a function as a spring, and has a hollow 54 inside. The seal portion 50 has, for example, a protrusion 58 on the upper surface, but the protrusion 58 may not be formed. The flow section 52 is formed of a hollow projecting portion so that the fluid can flow, and has a hollow 56 inside. The hollow 54 of the seal portion 50 and the hollow 56 of the flow section 52 are connected, and the fluid flowing through the flow section 52 flows through the hollow 54 of the seal section 50. The seal portion 50 and the distribution portion 52 are formed by, for example, press working. In addition, in FIG. 1A, since two seal portions 50 extend side by side between the oxidant gas discharge manifold 38 and the refrigerant flow path 26, the distribution portion 52 in FIG. 2A is Although it extends across the two seals 50, only one seal 50 is shown for clarity.

The plurality of distribution units 52 are arranged side by side with each other. The distance between the plurality of distribution units 52 is not constant, and there are wide portions and narrow portions. That is, the plurality of distribution units 52 include the distribution units 52a and 52b adjacent to each other with a narrow narrow interval 62 and the distribution units 52b and 52c adjacent to each other with a wide and wide interval 60.

As shown in FIG. 2C, the insulating frame 30 is joined to the surface of the anode side separator 22a on the side opposite to the protruding side of the sealing portion 50 and the plurality of flow portions 52. The anode side separator 22a and the insulating frame 30 are joined by, for example, an adhesive or thermocompression bonding. The bonding between the anode side separator 22a and the insulating frame 30 is performed by applying a load from both the anode side separator 22a and the insulating frame 30.

The cathode side separator 22c is joined to the surface of the insulating frame 30 opposite to the surface to which the anode side separator 22a is joined. The cathode side separator 22c and the insulating frame 30 are joined by, for example, an adhesive or thermocompression bonding. The bonding between the cathode side separator 22c and the insulating frame 30 is performed by applying a load from both the cathode side separator 22c and the insulating frame 30. The anode-side separator 22a, the insulating frame 30, and the cathode-side separator 22c are laminated in this order, and a load is applied from both the anode-side separator 22a and the cathode-side separator 22c to apply a load to the anode-side separator 22a, the insulating frame 30, and the cathode. The side separator 22c may be joined at once.

The cathode side separator 22c has a hollow protruding portion 44 at a position corresponding to the sealing portion 50 of the anode side separator 22a on the surface opposite to the insulating frame 30. The protrusion 44 is formed by, for example, pressing. An elastic member 46 is provided on the surface of the protrusion 44 opposite to the insulating frame 30. The projecting portion 44 and the elastic member 46 extend along the extending direction of the sealing portion 50. The elastic member 46 is made of, for example, rubber or an elastomer resin (for example, a thermoplastic elastomer resin), and is formed by coating or sheet sticking. The cathode side separator 22c may not be provided with the protruding portion 44, and the elastic member 46 may be provided on the flat surface at a position corresponding to the sealing portion 50 of the anode side separator 22a.

As shown in FIG. 2D, when a plurality of single cells 10 are laminated, the protrusions 58 of the seal portion 50 provided on the anode side separator 22a of the single cells 10a among the plurality of single cells 10 are adjacent to each other. It comes into contact with the elastic member 46 provided on the cathode side separator 22c of the single cell 10b. As a result, the seal portion 50 is elastically deformed, and the fluid flowing through the manifold is sealed by the reaction force. Further, when the cathode side separator 22c is provided with the protruding portion 44, the protruding portion 44 is also elastically deformed to generate a reaction force.

In explaining the effect of Example 1, a fuel cell of a comparative example will be described. FIG. 3 is a plan view of a portion corresponding to the region A in FIG. 1A in the fuel cell according to the comparative example. As shown in FIG. 3, the plurality of distribution units 52 are all lined up at regular intervals, and the intervals are the narrow intervals 62 described above. The reason why the plurality of flow units 52 are arranged at narrow intervals 62 in this way is to secure the flow amount of the fluid. Since other configurations are the same as those in the first embodiment, the description thereof will be omitted.

Here, the joining of the anode side separator 22a and the insulating frame 30 will be described. FIG. 4A is a diagram for explaining the bonding between the anode side separator 22a and the insulating frame 30 in the comparative example, and FIG. 4B is a diagram for explaining the bonding between the anode side separator 22a and the insulating frame 30 in the first embodiment. Is. In FIGS. 4 (a) and 4 (b), the region where the anode-side separator 22a is joined to the insulating frame 30 with sufficient strength is shown by a crosshatch.

The anode side separator 22a and the insulating frame 30 are joined by applying a load from both the anode side separator 22a and the insulating frame 30, but at that time, the portion to which the load is applied by directly pressing is joined with sufficient strength. However, the joint strength of the part that is not directly pressed is lower than that of the part that is directly loaded.

In the comparative example, since the plurality of distribution units 52 are lined up at narrow intervals 62, it is difficult to insert a jig for applying a load between the adjacent distribution units 52. It is conceivable to apply a load to the upper surface of the distribution unit 52, but it is difficult because surfaces having different heights are pressed at the same time, and it is difficult for the load to be transmitted to the joint surface due to deformation of the distribution unit 52 or the like. Therefore, as shown in FIG. 4A, the anode-side separator 22a and the insulating frame 30 are sufficiently large on both sides of the seal portion 50 in regions other than the circulation portion region 64 in which the plurality of circulation portions 52 are provided. Although the bonding is performed with strength, the bonding strength on both sides of the sealing portion 50 is low in the distribution portion region 64.

On the other hand, in the first embodiment, the plurality of distribution units 52 are arranged side by side with a wide interval 60 and a narrow interval 62. By providing such a wide interval 60, a jig for applying a load can be inserted. Further, in the case of thermocompression bonding, heat is easily transferred. Therefore, as shown in FIG. 4B, the anode side separator 22a and the insulating frame 30 are adjacent to each other on both sides of the seal portion 50 in a region other than the circulation portion region 64 at a wide interval 60 in the circulation portion region 64. It is joined to both sides of the sealing portion 50 in the region between the distribution portions 52 with sufficient strength. For this reason, it is preferable to provide wide intervals 60 at a constant pitch.

Next, the test performed by the inventor will be described. The inventor prepared the sample shown in FIG. 4A as a comparative example and the sample shown in FIG. 4B as Example 1 and tested the seal linear pressure of the seal portion 50. FIG. 5A is a diagram illustrating a test method for the seal linear pressure. As shown in FIG. 5A, the seal linear pressure test was performed by stacking four prepared samples 70 using a film-type pressure distribution measurement system manufactured by Tekscan, and using the second and third samples 70. This was performed by applying a compressive load from the vertical direction of the four samples 70 with the sheet sensor 72 inserted between them.

FIG. 5B is a diagram showing the test result of the seal linear pressure in Comparative Example, and FIG. 5C is a diagram showing the test result of the seal linear pressure in Example 1. In FIGS. 5 (b) and 5 (c), the horizontal axis is the amount of compression stroke per sample 70, and the vertical axis is the average seal line pressure (load / seal line length) obtained by dividing the load by the seal line length. .. The test results of the seal linear pressure in the circulation portion region 64 of the rectangularly extending seal portions 50 are indicated by ×, and the test results of the seal linear pressure in the three straight portions without the circulation portion region 64 are shown by ○ and Δ. , ◇.

As shown in FIG. 5B, in the comparative example, the seal linear pressure (x mark) of the seal portion 50 in the distribution portion region 64 is the seal linear pressure (◯,) of the linear seal portion 50 without the circulation portion region 64. It is lower than (△, ◇ mark). On the other hand, as shown in FIG. 5C, in the first embodiment, the seal linear pressure (x mark) of the seal portion 50 in the distribution portion region 64 is the seal linear pressure of the linear seal portion 50 without the circulation portion region 64. It is about the same size as (○, △, ◇).

As described above, in Example 1, it is considered that the improvement in the seal linear pressure of the seal portion 50 in the distribution portion region 64 is due to the following reasons. 6 (a) and 6 (b) are diagrams for explaining the reason why the seal linear pressure of the seal portion 50 in the distribution portion region 64 is improved. FIG. 6A is a diagram illustrating the seal of the seal portion 50 in the distribution section region 64 in the comparative example, and FIG. 6B is a seal of the seal portion 50 in the distribution section region 64 in the first embodiment. It is a figure explaining.

In the comparative example, as described above, the bonding strength between the anode-side separator 22a and the insulating frame 30 on both sides of the sealing portion 50 is low in the distribution portion region 64. Therefore, as shown in FIG. 6A, when the elastic member 46 comes into contact with the seal portion 50 and the seal portion 50 is deformed, the anode-side separator 22a may slide and spread with respect to the insulating frame 30. Since one end of the distribution section 52 is connected to the manifold, the anode-side separator 22a may slide and spread at least toward the manifold side. When the anode-side separator 22a slides and spreads, the reaction force due to the elastic deformation of the seal portion 50 becomes small. Therefore, in the comparative example, it is considered that the seal linear pressure of the seal portion 50 in the distribution portion region 64 is lowered.

On the other hand, in the first embodiment, as described above, the bonding strength between the anode side separator 22a and the insulating frame 30 on both sides of the sealing portion 50 between the circulating portions 52 adjacent to each other at a wide interval 60 in the circulating portion region 64 Large enough. Therefore, as shown in FIG. 6B, when the elastic member 46 comes into contact with the seal portion 50 and the seal portion 50 is deformed, the anode-side separator 22a is prevented from sliding and spreading with respect to the insulating frame 30. .. Therefore, in Example 1, it is considered that a large reaction force is obtained due to the elastic deformation of the seal portion 50, and the seal linear pressure is improved.

According to the first embodiment, as shown in FIGS. 2A and 2B, the plurality of distribution units 52 provided on the anode side separator 22a are adjacent to the distribution units 52a and 52b at narrow intervals 62. , Includes distribution units 52b, 52c, which are adjacent at wide intervals 60. As shown in FIG. 4B, the anode-side separator 22a is a seal portion between both sides of the seal portion 50 other than the distribution portion region 64 and the circulation portions 52b and 52c adjacent to each other at a wide interval 60 in the distribution portion region 64. Both sides of the 50 are joined to the insulating frame 30. As a result, as described with reference to FIGS. 5A to 6B, the seal linear pressure of the seal portion 50 in the distribution portion region 64 can be improved, and as a result, the occurrence of seal defects can be suppressed. Can be done.

In the first embodiment, the case where the anode side separator 22a is provided with the seal portion 50 and the circulation portion 52 is shown as an example, but even if the cathode side separator 22c is provided with the seal portion 50 and the distribution portion 52. Good.

FIG. 7 is a perspective view of the single cell 10 in the vicinity of the distribution section 52 in the second embodiment. As shown in FIG. 7, the single cell 10 in the second embodiment is arranged in the order of the anode side separator 22a, the cathode side separator 22c, and the insulating frame 30. The cathode side separator 22c is joined to the surface of the anode side separator 22a opposite to the side on which the sealing portion 50 and the flow portion 52 protrude. The anode-side separator 22a is joined to the cathode-side separator 22c at both sides of the seal portion 50 other than the circulation portion region 64 and both sides of the seal portion 50 at the wide interval 60 of the circulation portion region 64, as in the first embodiment. ing. The anode-side separator 22a and the cathode-side separator 22c are joined by, for example, an adhesive or laser welding. The insulating frame 30 is bonded to the surface of the cathode side separator 22c opposite to the anode side separator 22a. The cathode side separator 22c and the insulating frame 30 are joined by, for example, an adhesive or thermocompression bonding.

The insulating frame 30 is provided with a protrusion 58a made of an elastic member, and when the protrusion 58a comes into contact with the seal portion 50 of the adjacent single cell 10, the fluid flowing through the manifold is sealed. When the insulating frame 30 is an elastic member, the protrusion 58a may be formed by the insulating frame 30 or may be formed of a member different from the insulating frame 30. When the insulating frame 30 is not an elastic member, the protrusion 58a is formed by joining the elastic member to the insulating frame 30.

In the first embodiment, the single cell 10 in which the insulating frame 30 is sandwiched between the anode side separator 22a and the cathode side separator 22c, that is, the single cell 10 in which the anode side separator 22a, the insulating frame 30, and the cathode side separator 22c are laminated in this order. The case is shown as an example. However, the case is not limited to this case, and a single cell 10 in which the anode side separator 22a, the cathode side separator 22c, and the insulating frame 30 are laminated in this order may be used as in the second embodiment.

Although the examples of the present invention have been described in detail above, the present invention is not limited to such specific examples, and various modifications and modifications are made within the scope of the gist of the present invention described in the claims. It can be changed.

10-10b Single cell 12 film electrode junction 14 Electrolyte membrane 16a Anode catalyst layer 16c Cathode catalyst layer 18a Anode gas diffusion layer 18c Cathode gas diffusion layer 20 Film electrode gas diffusion layer junction 22a Anode side separator 22c Cathode side separator 24a Anode gas Flow path 24c Cathode gas flow path 26 Refrigerator flow path 30 Insulation frame 32 Fuel gas supply manifold 34 Fuel gas discharge manifold 36 Oxidate gas supply manifold 38 Oxidate gas discharge manifold 40 Refrigerator supply manifold 42 Refrigerator discharge manifold 44 Projection 46 Elastic member 50 Sealing part 52 Flowing part 54, 56 Hollow 58, 58a Protrusion 60 Wide spacing 62 Wide narrow spacing 64 Flowing part area

Claims (1)

A single cell having a pair of separators and an insulating frame arranged side by side with the pair of separators in the stacking direction of the pair of separators and surrounding the membrane electrode gas diffusion layer junction.
A manifold comprising the pair of separators and a manifold through which the fluid flows through the insulating frame.
One of the pair of separators is a seal composed of a hollow first protrusion that at least extends between the manifold and the flow path arranged so as to overlap the membrane electrode gas diffusion layer joint body. A plurality of circulations including a portion and a hollow second protruding portion that extends so as to intersect the seal portion and allows the fluid to flow between the manifold and the seal portion on the side opposite to the manifold. With a part,
In the plurality of distribution units, a group of distribution units composed of two or more distribution units adjacent to each other at the first interval are adjacent to each other at a second interval wider than the first interval .
The one separator is the seal portion between both sides of the seal portion other than the distribution portion region provided with the plurality of distribution portions and the distribution portion group adjacent to each other at the second interval in the distribution portion region. A fuel cell bonded to the other separator of the pair of separators or the insulating frame on both sides of the.

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