JP2023159639A - fuel cell stack - Google Patents

Abstract

To provide a fuel cell stack capable of suppressing reduction in sealability of a cell laminate for a long time.SOLUTION: A fuel cell stack comprises: a cell laminate 10 configured by laminating a plurality of single cells 90 each including a power generation part 11; and two end plates positioned at both sides of the cell laminate 10 in a first direction X of the single cell 90. The fuel cell stack also comprises a multilayer elastic body 60A positioned between the cell laminate 10 and the end plates in the first direction X and provided at one side of the cell laminate 10 in the first direction X. The multilayer elastic body 60A is formed by alternately laminating rigid plates 67 and elastic rubber layers 68 in the first direction X and provided over an entire region overlapped with the power generation part 11 in the first direction X.SELECTED DRAWING: Figure 2

Description

The present invention relates to a fuel cell stack.

Patent Document 1 discloses a cell stack structure of a fuel cell. The cell stack structure described in Patent Document 1 includes a cell stack, a first plate, a second plate, a third plate, and an elastic member. A cell stack is configured by stacking a plurality of single cells in the vertical direction. A single cell includes a power generation section called a membrane electrode assembly and a pair of separators that sandwich the power generation section from both sides in the vertical direction. The first plate is spaced upwardly from the top surface of the cell stack. A second plate is positioned adjacent the top surface of the cell stack. A third plate is located adjacent the bottom surface of the cell stack. An expandable member that can expand and contract in the vertical direction is arranged between the first plate and the second plate. A plurality of elastic members are arranged in a compressed state between the first plate and the second plate, and are arranged at equal intervals. The expandable member applies surface pressure to the cell stack via the second plate. As a result, even if the cell stack thermally expands due to an increase in internal pressure at the start of power generation, for example, the sealing performance between the single cells that make up the cell stack will not deteriorate due to surface pressure applied by the expandable member. be done.

JP 2021-111573 Publication

By the way, in the case of the cell stack structure described in Patent Document 1, a plurality of elastic members are arranged at regular intervals, so in the second plate, there are parts where elastic members are arranged and parts where elastic members are not arranged. The surface pressure applied to the cell stack varies depending on the portion. Therefore, there is room for improvement in suppressing deterioration in sealing performance between single cells.

A fuel cell stack for solving the above problems includes a cell stack formed by stacking a plurality of single cells each having a power generation section, and two ends located on both sides of the cell stack in the stacking direction of the single cells. a plate, and a laminated elastic body located between the cell laminate and the end plate in the lamination direction and provided on at least one side of the cell laminate in the lamination direction, the laminated elastic body is formed by alternately laminating rigid plates and elastic rubber layers in the lamination direction, and is provided over the entire region overlapping with the power generation section in the lamination direction.

According to this configuration, the laminated elastic body applies surface pressure to the cell laminate over the entire region overlapping with the power generation section in the stacking direction. Thereby, it is possible to suppress variations in the surface pressure applied to the portion of the cell stack that thermally expands due to power generation depending on the position.

Moreover, according to the above configuration, the total thickness of each elastic rubber layer can be made smaller than when the member applying surface pressure is formed only of elastic rubber. Thereby, even if creep deformation of the elastic rubber layer occurs when the elastic rubber layer continues to be compressed due to thermal expansion of the cell laminate, the total amount of creep deformation can be reduced. Therefore, it is possible to suppress a decrease in the surface pressure applied by the laminated elastic body.

Therefore, deterioration of the sealing performance of the cell stack can be suppressed for a long period of time.

FIG. 1 is a cross-sectional view of a fuel cell stack according to one embodiment. FIG. 2 is an exploded perspective view of a cell stack and a laminated elastic body that constitute the fuel cell stack of FIG. 1. FIG. 3 is an exploded perspective view of a single cell that constitutes the fuel cell stack of FIG. 1. FIG. 4(a) is a cross-sectional view centered on the laminated elastic body in a natural state where no compressive load is applied, and FIG. 4(b) is a cross-sectional view of the laminated elastic body in an assembled state where a compressive load is applied. FIG. FIG. 5 is a cross-sectional view of a modified example of a laminated elastic body.

Hereinafter, one embodiment of a fuel cell stack will be described with reference to FIGS. 1 to 4.
Note that in each drawing, a part of the structure is exaggerated or simplified for convenience of explanation, so the dimensional ratio of each structure may be different from the actual one.

As shown in FIG. 1, the fuel cell stack includes a cell stack 10, two stacked elastic bodies 60A, 60B, two end plates 70A, 70B, and a case 80.
<Cell laminate 10>
As shown in FIG. 2, the cell stack 10 is formed by stacking a plurality of single cells 90.

As shown in FIG. 3, the single cell 90 includes a membrane electrode assembly (MEA) 11 (hereinafter referred to as the power generation section 11) and an electrically insulating sheet member 20 surrounding the power generation section 11. There is. Furthermore, the single cell 90 includes a cathode separator 50 and an anode separator 30 that sandwich the power generation section 11 and the sheet member 20.

As shown in FIGS. 2 and 3, the single cell 90 has a rectangular plate shape as a whole.
Note that, hereinafter, the stacking direction of the plurality of single cells 90 will be described as the first direction X.
Further, the extending direction of the long side and the extending direction of the short side of the single cell 90 will be described as a second direction Y and a third direction Z, respectively.

The single cell 90 has introduction holes 91 , 93 , and 95 for respectively introducing fuel gas, a cooling medium, and an oxidant gas into the single cell 90 , and inlet holes 91 , 93 , and 95 for introducing fuel gas, a cooling medium, and an oxidizing gas into the single cell 90 . It has lead-out holes 92, 94, and 96 for leading out to the outside, respectively.

The introduction holes 91, 93, 95 and the outlet holes 92, 94, 96 penetrate the single cell 90 in the first direction X. The introduction hole 91 and the outlet holes 94 and 96 are provided on one side of the unit cell 90 in the second direction Y (the left side in the left-right direction in FIG. 2). The introduction hole 91 and the outlet holes 94 and 96 are arranged in order at intervals in the third direction Z. The outlet hole 92 and the introduction holes 93 and 95 are provided on the other side of the unit cell 90 in the second direction Y (the right side in FIG. 2). The outlet hole 92 and the introduction holes 93 and 95 are arranged in order in the third direction Z at intervals.

<Power generation section 11>
As shown in FIG. 3, the power generation section 11 includes a solid polymer electrolyte membrane (hereinafter referred to as electrolyte membrane) (not shown) and electrodes 11A and 11B provided on both sides of the electrolyte membrane. In addition, in this embodiment, the electrode joined to the surface of one side (the upper side in the vertical direction of FIG. 3) of the electrolyte membrane (not shown) in the first direction X is the cathode electrode 11A. Further, the electrode joined to the other side (lower side in FIG. 3) of the electrolyte membrane in the first direction X is the anode electrode 11B.

The electrodes 11A and 11B include a catalyst layer (not shown) joined to an electrolyte membrane, and a gas diffusion layer 12 (hereinafter referred to as GDL 12) joined to the catalyst layer.
The sheet member 20 is provided between the cathode separator 50 and the anode separator 30 that constitute the single cell 90. The sheet member 20 has a substantially rectangular plate shape in plan view that is long in the second direction Y. The sheet member 20 is made of, for example, an electrically insulating synthetic resin material.

The sheet member 20 has through holes 21, 22, 23, 24, 25, and 26 that constitute holes 91, 92, 93, 94, 95, and 96, respectively.
The sheet member 20 has an opening 27 in the center. The inner peripheral edge of the opening 27 is joined to the peripheral edge of the power generation section 11 from one side in the first direction X (the upper side in FIG. 3).

<Cathode side separator 50>
As shown in FIG. 3, the cathode-side separator 50 has a rectangular plate shape in plan view that is long in the second direction Y. As shown in FIG.

The cathode side separator 50 is formed by press-molding a thin metal plate of titanium, stainless steel, or the like.
The cathode separator 50 is provided on the cathode electrode 11A side of the power generation section 11.

The cathode side separator 50 has a first surface 50a that faces the power generation section 11, and a second surface 50b that is a surface opposite to the first surface 50a.
The cathode side separator 50 has through holes 51, 52, 53, 54, 55, and 56 that constitute holes 91, 92, 93, 94, 95, and 96, respectively.

The cathode side separator 50 has a plurality of groove channels 57 through which the oxidant gas flows and a plurality of groove channels 58 through which the cooling medium flows. The groove channel 57 is provided on the first surface 50a. The groove channel 58 is provided on the second surface 50b. In addition, in FIG. 3, in the cathode side separator 50, the outer edge of a portion where a plurality of groove channels 57 are formed and the outer edge of a portion where a plurality of groove channels 58 are formed are respectively shown in a simplified manner. .

<Anode side separator 30>
As shown in FIG. 3, the anode side separator 30 has a rectangular plate shape in plan view that is long in the second direction Y. As shown in FIG.

The anode side separator 30 is formed by press-molding a thin metal plate of titanium, stainless steel, or the like.
The anode side separator 30 is provided on the anode electrode 11B side of the power generation section 11.

The anode side separator 30 has a first surface 30a that faces the power generation section 11, and a second surface 30b that is a surface opposite to the first surface 30a.
The anode side separator 30 has through holes 31, 32, 33, 34, 35, and 36 that constitute holes 91, 92, 93, 94, 95, and 96, respectively.

The anode side separator 30 has a plurality of groove channels 37 through which fuel gas flows and a plurality of groove channels 38 through which a cooling medium flows. The groove channel 37 is provided on the first surface 30a. The groove channel 38 is provided on the second surface 30b. In addition, in FIG. 3, the outer edge of the part where the plurality of groove channels 37 are formed and the outer edge of the part where the plurality of groove channels 38 are formed in the anode side separator 30 are respectively shown in a simplified manner. .

<Case 80>
As shown in FIG. 1, the case 80 has a cylindrical shape with a rectangular cross section and is open on both sides in the first direction. The case 80 surrounds the side surfaces of the cell stack 10. A gap is provided between the inner peripheral surface 80a of the case 80 and the cell stack 10.

<End plates 70A, 70B>
As shown in FIG. 1, an end plate 70A is provided on one side (upper side in FIG. 1) of the cell stack 10 in the first direction X. An end plate 70B is provided on the other side of the cell stack 10 (lower side in FIG. 1) in the first direction X. End plates 70A and 70B each close the opening of case 80. The end plates 70A and 70B are connected to each other by bolts and nuts (not shown) extending in the first direction X.

<Laminated elastic body 60A, 60B>
As shown in FIG. 1, the laminated elastic bodies 60A, 60B are located between the cell laminate 10 and the end plates 70A, 70B in the first direction X. A gap is provided between the inner peripheral surface 80a of the case 80 and the laminated elastic bodies 60A, 60B. The laminated elastic body 60A is provided on one side of the cell laminate 10 (upper side in FIG. 1) in the first direction X. The laminated elastic body 60B is provided on the other side of the cell laminate 10 (lower side in FIG. 1) in the first direction X. That is, the laminated elastic bodies 60A and 60B are provided on both sides of the cell laminate 10 in the first direction X, respectively.

The laminated elastic bodies 60A and 60B are provided adjacent to the end faces 10a and 10b of the cell laminate 10 in the first direction X, respectively.
As shown in FIGS. 1 and 2, the laminated elastic bodies 60A and 60B are provided over the entire region overlapping with the power generation section 11 in the first direction X. The laminated elastic body 60A of this embodiment is provided over the entire end surface 10a of the cell laminate 10. The laminated elastic body 60B of this embodiment is provided over the entire end surface 10b of the cell laminate 10.

As shown in FIGS. 2, 4(a), and 4(b), the laminated elastic body 60A is formed by laminating a plurality of rigid plates 67 and elastic rubber layers 68 alternately in the first direction X. There is. The rigid plate 67 and the elastic rubber layer 68 are bonded to each other with, for example, an adhesive.

The elastic rubber layer 68 has a substantially rectangular plate shape in plan view that is long in the second direction Y.
The elastic rubber layer 68 of this embodiment has electrical insulation properties.
Note that the elastic rubber layer 68 is made of rubber such as natural rubber or synthetic rubber.

The rigid plate 67 has a substantially rectangular plate shape in plan view that is long in the second direction Y. The rigid plate 67 of this embodiment has a flat plate shape and does not have a through hole. Therefore, the rigid plate 67 isolates the elastic rubber layers 68 adjacent to each other in the first direction X over the entire region overlapping with the power generation section 11 in the first direction X. Note that the rigid plate 67 is formed of a thin metal plate such as aluminum or stainless steel.

As shown in FIG. 2, the laminated elastic body 60A is provided with through holes 61, 62, 63, 64, 65, and 66 that penetrate the laminated elastic body 60A in the first direction X. The through holes 61, 64, and 66 are provided at positions corresponding to the holes 91, 94, and 96 of the single cell 90, respectively. The through holes 62, 63, and 65 are provided at positions corresponding to the holes 92, 93, and 95 of the single cell 90, respectively.

Although not shown in the drawings, the laminated elastic body 60B is not provided with through holes 61, 62, 63, 64, 65, and 66.
As shown in FIGS. 4(a) and 4(b), the elastic rubber layer 68 of the laminated elastic body 60A is in contact with the end surface 10a of the cell laminate 10. Further, although not shown, the elastic rubber layer 68 of the laminated elastic body 60B is in contact with the end surface 10b of the cell laminate 10.

As shown in FIG. 4(b), in the assembled state in which the end plates 70A and 70B are connected to each other by the bolts and nuts, the laminated elastic body 60A is compressed in the first direction X. At this time, the elastic rubber layer 68 protrudes toward the inner peripheral surface 80a of the case 80.

Next, the operation of this embodiment will be explained.
By the laminated elastic bodies 60A and 60B, surface pressure is applied to the cell laminated body 10 over the entire region overlapping with the power generation section 11 in the first direction X. Thereby, it is possible to suppress variations in the surface pressure applied to the portion of the cell stack 10 that thermally expands due to power generation depending on the position.

Furthermore, the total thickness of each elastic rubber layer 68 can be made smaller than when the member applying surface pressure is formed only of elastic rubber. Thereby, even if creep deformation of the elastic rubber layer 68 occurs when the elastic rubber layer 68 continues to be compressed due to thermal expansion of the cell laminate 10, the total amount of creep deformation can be reduced. Therefore, it is possible to suppress the surface pressure applied by the laminated elastic bodies 60A and 60B from decreasing.

Next, the effects of this embodiment will be explained.
(1) The laminated elastic bodies 60A, 60B are located between the cell laminated body 10 and the end plates 70A, 70B in the first direction X. The laminated elastic bodies 60A and 60B are formed by alternately laminating rigid plates 67 and elastic rubber layers 68 in the first direction X, and are provided over the entire region overlapping with the power generation section 11 in the first direction X. There is.

According to such a configuration, since the above-described effects are achieved, deterioration in the sealing performance of the cell stack 10 can be suppressed over a long period of time.
(2) The laminated elastic bodies 60A and 60B are provided adjacent to the end surfaces 10a and 10b on both sides of the cell laminated body 10 in the first direction X. The elastic rubber layer 68 has electrical insulation properties and is in contact with the end surfaces 10a and 10b.

According to such a configuration, in a configuration in which the laminated elastic bodies 60A, 60B are provided adjacent to the end faces 10a, 10b of the cell laminated body 10, it is possible to electrically insulate the laminated elastic bodies 60A, 60B and the cell laminated body 10. can be easily done.

(3) The laminated elastic bodies 60A and 60B are provided on both sides of the cell laminate 10 in the first direction X, respectively.
According to this configuration, surface pressure is applied to the cell stack 10 from both sides in the first direction X by the stacked elastic bodies 60A and 60B. Thereby, it is possible to further suppress variations in the surface pressure applied to the portion of the cell stack 10 that thermally expands due to power generation depending on the position.

(4) The rigid plate 67 isolates the elastic rubber layers 68 adjacent to each other in the first direction X over the entire region overlapping with the power generation section 11 in the first direction X.
According to such a configuration, the surface pressure applied to the cell stack 10 from the stacked elastic bodies 60A, 60B can be made uniform. Thereby, it is possible to further suppress variations in the surface pressure applied to the portion of the cell stack 10 that thermally expands due to power generation depending on the position.

<Example of change>
This embodiment can be modified and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

- As shown in FIG. 5, the rigid plate 67 may have a through hole 100 that penetrates the rigid plate 67 in the first direction X.
In the power generation section 11, there are regions that are susceptible to thermal expansion and regions that are difficult to thermally expand.

According to the above configuration, of the laminated elastic bodies 60A and 60B, the portion where the through hole 100 is provided in the rigid plate 67 is more likely to be elastically deformed in the first direction X than the portion where the through hole 100 is not provided. Become. For this reason, for example, if the through holes 100 are provided in the rigid plate 67 at positions corresponding to the portions of the power generation section 11 that are likely to undergo thermal expansion, the thermal expansion of the cell laminate 10 can be effectively controlled by the laminated elastic bodies 60A and 60B. can be absorbed. In this way, by appropriately setting the position, size, and shape of the through hole 100, it is easy to partially adjust the surface pressure applied to the cell stack 10 from the stacked elastic bodies 60A, 60B. Can be done.

- Either one of the laminated elastic bodies 60A and 60B may be omitted.
- The rigid plates 67 of the laminated elastic bodies 60A, 60B may be in contact with the end surfaces 10a, 10b of the cell laminate 10. In this case, it is preferable to provide an electrically insulating sheet between the laminate elastic bodies 60A, 60B and the end faces 10a, 10b of the cell laminate 10.

- In the above embodiment, the laminated elastic bodies 60A, 60B are provided over the entire end surfaces 10a, 10b of the cell laminate 10, but the present invention is not limited to this. The laminated elastic bodies 60A, 60B may be provided over the entire region overlapping with the power generation section 11 in the first direction X, or may be provided only in the region overlapping with the power generation section 11 in the first direction X. .

DESCRIPTION OF SYMBOLS 10... Cell laminate 10a, 10b... End face 11... Power generation part 11A... Cathode electrode 11B... Anode electrode 12... Gas diffusion layer 20... Sheet member 21-26... Through hole 27... Opening part 30... Anode side separator 30a... First Surface 30b...Second surface 31-36...Through hole 37, 38...Groove flow path 50...Cathode side separator 50a...First surface 50b...Second surface 51-56...Through hole 57, 57...Groove flow path 60A, 60B ...Laminated elastic body 61-66...Through hole 67...Rigid plate 68...Elastic rubber layer 70A, 70B...End plate 80...Case 80a...Inner peripheral surface 90...Single cell 91, 93, 95...Introduction hole 92, 94, 96 ...Derivation hole 100...Through hole X...First direction (stacking direction)
Y...Second direction Z...Third direction

Claims (5)

A cell stack formed by stacking a plurality of single cells each having a power generation section;
two end plates located on both sides of the cell stack in the stacking direction of the single cells;
a laminated elastic body located between the cell laminate and the end plate in the lamination direction and provided on at least one side of the cell laminate in the lamination direction,
The laminated elastic body is formed by alternately laminating rigid plates and elastic rubber layers in the lamination direction, and is provided over the entire region overlapping with the power generation section in the lamination direction.
fuel cell stack. The laminated elastic body is provided adjacent to at least one end surface of the cell laminate in the lamination direction,
The elastic rubber layer has electrical insulation and is in contact with the end surface.
The fuel cell stack according to claim 1. The laminated elastic body is provided on both sides of the cell laminate in the lamination direction,
The fuel cell stack according to claim 1 or 2. The rigid plate isolates the elastic rubber layers adjacent in the stacking direction over the entire region overlapping with the power generation section in the stacking direction.
The fuel cell stack according to claim 1. The rigid plate has a through hole that penetrates the rigid plate in the lamination direction.
The fuel cell stack according to claim 1.

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