JP2021118101A - Adhesive structure of single cell of fuel cell stack and adhesive sheet for single cell of fuel cell stack - Google Patents

Abstract

To provide an adhesive structure of a single cell of a fuel cell stack and an adhesive sheet for a single cell of a fuel cell stack which can easily bond a membrane electrode assembly, a frame member, and a separator.SOLUTION: An adhesive structure of a single cell of a fuel cell stack is applied to a single cell of a fuel cell stack including a hard resin frame member 10 having an opening 11 in the center, a MEA 20 that is overlapped on one surface of the frame member 10 and covers the opening 11, and a separator 30 that is overlapped on the one surface of the frame member 10, and the MEA 20 and the separator 30 are adhered to the frame member 10. The adhesive structure further includes an adhesive sheet 40 having a first adhesive portion 40A that extends along the peripheral edge of the opening 11 and adheres the frame member 10 and the MEA 20, and a second adhesive portion 40B that is connected to the outer peripheral side of the first adhesive portion 40A, and adhere the frame member 10 and the separator 30.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive structure of a membrane electrode assembly, a frame member, and a separator constituting a single cell of a fuel cell stack, and an adhesive sheet used for the adhesive structure.

The polymer electrolyte fuel cell includes a fuel cell stack formed by stacking a plurality of single cells. The single cell includes a membrane electrode assembly (MEA), a resin frame member that supports the peripheral edge of the MEA, and a pair of separators that sandwich the membrane electrode assembly and the frame member. .. Specifically, the single cell includes a membrane electrode gas diffusion layer assembly (MEGA) in which gas diffusion layers are bonded to both sides of the MEA.

The MEA has a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane), an anode electrode bonded to one surface of the electrolyte membrane, and a cathode electrode bonded to the other surface of the electrolyte membrane.
Patent Document 1 discloses a method for producing a single cell. In this manufacturing method, a step of providing a first adhesive on one surface of the frame member, a step of providing a second adhesive on the surface of the frame member facing the one surface in MEGA, and a second adhesive are used. It includes a step of adhering the MEGA and the frame member and a step of adhering the frame member and the separator via the first adhesive.

Japanese Unexamined Patent Publication No. 2019-71263

By the way, in the method for manufacturing a single cell described in Patent Document 1, a step of providing a first adhesive on one surface of a frame member and a step of providing a second adhesive on MEGA are performed separately. Therefore, there arises a problem that the process of providing the adhesive becomes complicated.

An object of the present invention is to provide a single-cell adhesive structure of a fuel cell stack capable of easily adhering a membrane electrode assembly, a frame member, and a separator, and an adhesive sheet for a single cell of a fuel cell stack. It is in.

The single cell bonding structure of the fuel cell stack for achieving the above object is a frame member made of hard resin having an opening in the center, and a membrane electrode assembly that is superposed on one surface of the frame member and covers the opening. It is applied to a single cell of a fuel cell stack including a body and a separator superimposed on the one surface of the frame member, and adheres the membrane electrode assembly and the separator to the frame member. This adhesive structure extends along the peripheral edge of the opening and is connected to the first adhesive portion for adhering the frame member and the membrane electrode assembly to the outer peripheral side of the first adhesive portion, and the frame. An adhesive sheet having a second adhesive portion for adhering the member and the separator is provided.

The adhesive sheet for achieving the above object is a frame member made of a hard resin having an opening in the center, a membrane electrode assembly that is superposed on one surface of the frame member and covers the opening, and the frame member. It is applied to a single cell of a fuel cell stack having a separator superimposed on one of the surfaces, and the membrane electrode assembly and the separator are adhered to the frame member. This adhesive sheet extends along the peripheral edge of the opening and is connected to the first adhesive portion for adhering the frame member and the membrane electrode assembly to the outer peripheral side of the first adhesive portion, and the frame. It has a second adhesive portion for adhering the member and the separator.

According to these configurations, the membrane electrode assembly and the separator are adhered to the frame member using the same adhesive sheet. Therefore, the membrane electrode assembly, the frame member, and the separator can be easily adhered.

According to the present invention, the membrane electrode assembly, the frame member, and the separator can be easily adhered.

FIG. 5 is a perspective view showing a frame member, an adhesive sheet, a membrane electrode assembly, and a separator separately for one embodiment of a single cell adhesive structure of a fuel cell stack. FIG. 2 is a cross-sectional view taken along the line 2-2 of FIG. The plan view which shows the adhesive sheet of the 1st modification. The plan view which shows the adhesive sheet of the 2nd modification.

Hereinafter, one embodiment will be described with reference to FIGS. 1 and 2.
As shown in FIG. 1, the single cell of the fuel cell stack has a frame member 10 having an opening 11 in the center, and a membrane electrode that is superposed on one surface (upper surface of the figure) of the frame member 10 and covers the opening 11. It includes a assembly (hereinafter referred to as MEA20) and a separator 30 on the cathode electrode side that is overlapped with the one surface of the frame member 10. The single cell includes an adhesive sheet 40 that adheres the MEA 20 and the separator 30 to the frame member 10, and a separator (not shown) on the anode electrode side that is superposed on the other surface of the frame member 10. The single cell has a rectangular plate shape as a whole.

Hereinafter, each component constituting a single cell of the fuel cell stack will be described in detail.
<MEA20>
As shown in FIGS. 1 and 2, the MEA 20 is bonded to a solid polymer electrolyte membrane (hereinafter referred to as an electrolyte membrane), a cathode electrode bonded to one surface of the electrolyte membrane, and the other surface of the electrolyte membrane. It has an anode electrode (all not shown).

The MEA 20 has a rectangular shape in a plan view. A gas diffusion layer (not shown) is bonded to both sides of the MEA 20.
<Frame member 10>
As shown in FIG. 1, the frame member 10 has a rectangular frame shape and has a rectangular opening 11 in a plan view at the center. The frame member 10 is made of hard resin.

On the outer peripheral portion of the frame member 10, a manifold hole 12a for supplying an oxidizing gas, a manifold hole 12b for supplying a coolant, a manifold hole 12c for supplying a fuel gas, a manifold hole 12d for discharging an oxidizing gas, and cooling A manifold hole 12e for discharging the liquid and a manifold hole 12f for discharging the fuel gas are provided.

As shown in FIGS. 1 and 2, the inner peripheral portion of one surface (upper surface of FIGS. 1 and 2) of the frame member 10 has a thin portion 13 having a rectangular frame shape in a plan view, which is thinner than the outer peripheral portion. Is provided. The outer edge shape of the thin portion 13 is slightly larger than the outer edge shape of the MEA 20.

<Separator 30>
As shown in FIGS. 1 and 2, the separator 30 has a rectangular plate shape, and the MEA 20 is in contact with one surface (lower surfaces of FIGS. 1 and 2) of the central portion 31. The separator 30 is made of a metal such as stainless steel.

On the outer periphery of the separator 30, a manifold hole 32a for supplying an oxidizing gas, a manifold hole 32b for supplying a coolant, a manifold hole 32c for supplying a fuel gas, a manifold hole 32d for discharging an oxidizing gas, and a coolant The manifold hole 32e for discharging the fuel gas and the manifold hole 32f for discharging the fuel gas are provided. The manifold holes 32a to 32f communicate with the manifold holes 12a to 12f of the frame member 10.

As shown in FIG. 2, on one surface (lower surface of the same figure) of the central portion 31 of the separator 30, a groove-shaped structure that communicates the manifold hole 32a for supplying the oxidizing gas and the manifold hole 32d for discharging the oxidizing gas. An oxidation gas flow path 33a is provided. On the other surface of the central portion 31 (upper surface in the figure), a groove-shaped coolant flow path 33b that connects the manifold hole 32b for supplying the coolant and the manifold hole 32e for discharging the coolant is provided. ing.

<Adhesive sheet 40>
As shown in FIG. 1, the adhesive sheet 40 is a so-called hot melt adhesive sheet containing a thermoplastic resin as an adhesive, and has a rectangular frame shape in a plan view. The outer edge shape of the adhesive sheet 40 is slightly smaller than the outer edge shape of the frame member 10. The inner edge shape of the adhesive sheet 40 is slightly larger than the inner edge shape of the thin portion 13 of the frame member 10.

On the outer periphery of the adhesive sheet 40, a manifold hole 42a for supplying oxide gas, a manifold hole 42b for supplying coolant, a manifold hole 42c for supplying fuel gas, a manifold hole 42d for discharging oxide gas, and cooling. A manifold hole 42e for discharging the liquid and a manifold hole 42f for discharging the fuel gas are provided. The manifold holes 42a to 42f communicate the manifold holes 12a to 12f of the frame member 10 and the manifold holes 32a to 32f of the separator 30.

As shown in FIGS. 1 and 2, the adhesive sheet 40 is sandwiched between the thin portion 13 and the outer peripheral portion of the frame member 10 and one surface (lower surface of FIGS. 1 and 2) of the MEA 20 and the separator 30. ..

As shown in FIG. 1, the adhesive sheet 40 extends along the peripheral edge of the opening 11 and has a first adhesive portion 40A and a first adhesive portion 40A for adhering the thin portion 13 of the frame member 10 and the MEA 20. It is connected to the outer peripheral side and has a second adhesive portion 40B for adhering the outer peripheral portion of the frame member 10 and the separator 30.

A plurality of slits 43 are provided between the first adhesive portion 40A and the second adhesive portion 40B as a restricting portion for restricting heat transfer from the first adhesive portion 40A side to the second adhesive portion 40B side. There is. The slit 43 extends linearly along the peripheral edge of the opening 11 and penetrates the adhesive sheet 40.

More specifically, the slit 43 is formed in a straight line on the periphery of the opening 11 (41) between the manifold hole 42c for supplying the fuel gas and the manifold hole 42b for supplying the coolant and the central opening 41. It extends along the extending part.

The slit 43 extends along a linearly extending portion of the peripheral edge of the opening 11 (41) between the manifold hole 42f for discharging the fuel gas and the manifold hole 42e for discharging the coolant and the opening 41. Exists.

Further, the slit 43 is not provided in the portion corresponding to the corner portion of the opening 11.
Next, the operation of this embodiment will be described.
Prior to adhering the MEA 20 and the separator 30 to the frame member 10 via the adhesive sheet 40, first, the frame member 10 and the adhesive sheet 40 are placed on the lower jig. At this time, the frame member 10 and the adhesive sheet 40 are positioned with respect to the lower jig by the positioning mechanism, and the displacement of the adhesive sheet 40 with respect to the frame member 10, particularly the displacement in the plane direction is regulated.

The MEA 20 is placed on the first adhesive portion 40A of the adhesive sheet 40 and heated while being sandwiched between the upper jig and the lower jig to melt the adhesive of the adhesive sheet 40, so that the MEA 20 is a frame member. It is adhered to 10.

Here, a slit 43 as a regulating portion is provided between the first adhesive portion 40A and the second adhesive portion 40B. The slit 43 regulates the transfer of heat from the first adhesive portion 40A side to the second adhesive portion 40B side.

Next, the upper jig is removed, and the separator 30 is placed on the second adhesive portion 40B and the MEA 20 of the adhesive sheet 40. At this time, the displacement of the separator 30 with respect to the frame member 10 is regulated by the positioning mechanism, particularly the displacement in the plane direction.

Then, the separator 30 is adhered to the second adhesive portion 40B of the frame member 10 by melting the adhesive of the adhesive sheet 40 by heating in a state of being sandwiched between the upper jig and the lower jig.

Next, the effect of this embodiment will be described.
(1) The single-cell adhesive structure of the fuel cell stack extends along the peripheral edge of the opening 11 and adheres the frame member 10 and the MEA 20 to the first adhesive portion 40A and the outer peripheral side of the first adhesive portion 40A. The adhesive sheet 40 is provided with a second adhesive portion 40B for adhering the frame member 10 and the separator 30.

According to such a configuration, the MEA 20 and the separator 30 are adhered to the frame member 10 using the same adhesive sheet 40. Therefore, the MEA 20, the frame member 10, and the separator 30 can be easily bonded.

(2) A slit 43 is provided between the first adhesive portion 40A and the second adhesive portion 40B as a restricting portion for restricting heat transfer from the first adhesive portion 40A side to the second adhesive portion 40B side. ing.
In a configuration in which the frame member 10 and the MEA 20 are adhered to each other by heating the first adhesive portion 40A, the following inconveniences may occur. That is, when the heat generated by heating the first adhesive portion 40A moves from the first adhesive portion 40A side to the second adhesive portion 40B side, the second adhesive portion 40B is wrinkled and the adhesive sheet 40 is adhered. The sex is reduced.

In this respect, according to the above configuration, the heat transfer from the first adhesive portion 40A side to the second adhesive portion 40B side is regulated by the slit 43 as the restricting portion. As a result, it is possible to prevent wrinkles from being generated in the second adhesive portion 40B. Therefore, it is possible to suppress the occurrence of inconveniences such as a decrease in the adhesiveness of the adhesive sheet 40.

(3) The regulating portion is a slit 43 extending along the peripheral edge of the opening 11 and penetrating the adhesive sheet 40.
According to such a configuration, a regulating portion can be easily provided on the adhesive sheet 40.

(4) The adhesive sheet 40 extends along the peripheral edge of the opening 11 and is connected to the first adhesive portion 40A for adhering the frame member 10 and the MEA 20 to the outer peripheral side of the first adhesive portion 40A, and the frame member. It has a second adhesive portion 40B for adhering the 10 and the separator 30.

According to such a configuration, the same effect as the above-mentioned effect (1) is obtained.
<Change example>
This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

The shape of the slit 43 is not limited to the shape exemplified in the above embodiment. For example, as shown in FIG. 3, each slit 43 illustrated in the above embodiment may be divided into a plurality of slits 43A in the extending direction thereof. Further, as shown in FIG. 4, a rectangular hole 43B in a plan view extending along the peripheral edge of the opening 11 may be formed.

-The regulation part is not limited to the slits 43 and 43A and the hole 43B. Alternatively, for example, the regulating portion may be composed of a material having a lower thermal conductivity than the main body of the adhesive sheet 40.
-The regulation part can be omitted.

The adhesive sheet 40 is not limited to a so-called hot melt adhesive sheet containing a thermoplastic resin as an adhesive, and may be formed, for example, by impregnating a sheet-shaped mesh member with a thermoplastic adhesive.

10 ... Frame member 11 ... Opening 12a, 12b, 12c, 12d, 12e, 12f ... Manifold hole 13 ... Thin-walled part 20 ... MEA
30 ... Separator 31 ... Central part 32a, 32b, 32c, 32d, 32e, 32f ... Manifold hole 33a ... Oxidation gas flow path 33b ... Coolant flow path 40 ... Adhesive sheet 40A ... First adhesive part 40B ... Second adhesive part 41 ... Openings 42a, 42b, 42c, 42d, 42e, 42f ... Manifold holes 43 ... Slits 43A ... Slits 43B ... Holes

Claims (4)

It includes a frame member made of a hard resin having an opening in the center, a membrane electrode assembly that is overlapped with one surface of the frame member and covers the opening, and a separator that is overlapped with the one surface of the frame member. In an adhesive structure that is applied to a single cell of a fuel cell stack and adheres the membrane electrode assembly and the separator to the frame member.
A first adhesive portion that extends along the peripheral edge of the opening and adheres the frame member and the membrane electrode assembly to the outer peripheral side of the first adhesive portion, and the frame member and the separator. It is provided with an adhesive sheet having a second adhesive portion for adhering.
Single cell adhesive structure of fuel cell stack. The first adhesive portion adheres the frame member and the membrane electrode assembly by being heated.
Between the first adhesive portion and the second adhesive portion, a restricting portion that regulates the transfer of heat from the first adhesive portion side to the second adhesive portion side is provided.
The single cell adhesive structure of the fuel cell stack according to claim 1. The restricting portion is a slit extending along the peripheral edge of the opening and penetrating the adhesive sheet.
The single cell adhesive structure of the fuel cell stack according to claim 2. It includes a frame member made of a hard resin having an opening in the center, a membrane electrode assembly that is overlapped with one surface of the frame member and covers the opening, and a separator that is overlapped with the one surface of the frame member. In an adhesive sheet that is applied to a single cell of a fuel cell stack and adheres the membrane electrode assembly and the separator to the frame member.
A first adhesive portion that extends along the peripheral edge of the opening and adheres the frame member and the membrane electrode assembly to the outer peripheral side of the first adhesive portion, and the frame member and the separator. Has a second adhesive part, which adheres the
Adhesive sheet for single cell of fuel cell stack.

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