Fuel cell separators and fuel cell stacks

Abstract

To provide a separator for fuel cells capable of suppressing occurrence of warpage in the separator, and a fuel cell stack.SOLUTION: A cathode-side separator 30 comprises a plurality of main flow passages 51 which is opposed to a power generation section 10 and in which an oxidant gas flows. The cathode-side separator 30 also comprises: a supply-side manifold hole 36 through which the oxidant gas is supplied toward the plurality of main flow passages 51; and an exhaust-side manifold hole 39 through which the oxidant gas from the main flow passages 51 is exhausted. The cathode-side separator 30 further comprises: a plurality of supply-side connection flow passages 52 connecting the supply-side manifold hole 36 with the plurality of main flow passages 51; and a plurality of exhaust-side connection flow passages 53 connecting the exhaust-side manifold hole 39 with the plurality of main flow passages 51. A protrusion 54 protruding toward the power generation section 10 is provided in a part of the supply-side connection flow passages 52 and the exhaust-side connection flow passages 53 in an extension direction of the connection flow passages.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a separator for a fuel cell and a fuel cell stack.

Background Art

[0002] Patent Document 1 discloses a fuel cell stack composed of a plurality of single cells stacked. A single cell has a power generation part and two separators sandwiching the power generation part. Each separator is provided with supply holes and discharge holes that penetrate in the stacking direction of the single cells and through which reaction gas flows. On one surface of each separator having a surface facing the power generation part, a plurality of flow path grooves through which reaction gas flows and ribs provided between adjacent flow path grooves are provided. The flow path grooves have a main flow path provided on the facing surface, a supply-side connection flow path connecting the supply hole and the main flow path, and a discharge-side connection flow path connecting the main flow path and the discharge hole. Each separator has a metal base material. The base material is formed by press molding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in such a fuel cell stack, when the base material of the separator is press-molded, the portions around the supply holes, the portions around the discharge holes, and the flow path grooves are particularly deformed greatly. Therefore, residual stress is likely to occur in the base material of the separator. As a result, the separator may be warped.

Means for Solving the Problems

[0005] A fuel cell separator for solving the above problems is a fuel cell separator arranged opposite the power generation section of a fuel cell, and comprises a plurality of main passages through which a reaction gas flows, facing the power generation section; a supply-side manifold hole for supplying the reaction gas to the plurality of main passages; a discharge-side manifold hole for discharging the reaction gas from the main passages; a plurality of supply-side connecting passages connecting the supply-side manifold hole to the plurality of main passages; and a plurality of discharge-side connecting passages connecting the discharge-side manifold hole to the plurality of main passages, wherein a projection is provided in the extending direction of at least one of the supply-side connecting passages and the discharge-side connecting passages, projecting toward the power generation section.

[0006] With this configuration, the rigidity of at least one of the supply-side and discharge-side connection channels is increased by the protruding portion. Therefore, warping of the separator can be suppressed.

[0007] Furthermore, a fuel cell stack for solving the above problems is a fuel cell stack formed by stacking a plurality of single cells, each having a power generation unit and a first separator and a second separator sandwiching the power generation unit, wherein the first separator has adjacent second separators of other single cells, at least one of the first separator and the second separator of the other single cell is a fuel cell separator, the at least one separator has a cooling channel through which a refrigerant flows on the side opposite to the side where the main flow path is provided, the cooling channel is located between at least one adjacent connecting channel, the protrusion is provided over the entire width of the at least one connecting channel, and the opposite side has a groove formed by the protrusion that connects the adjacent cooling channels.

[0008] According to this configuration, a protrusion provided in one of the connecting channels creates a groove that connects adjacent cooling channels. The refrigerant flowing through the cooling channel flows through this groove. As a result, the surface area of ​​the cooling channel increases by the amount of the groove. This improves the cooling efficiency of the fuel cell stack. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is an exploded perspective view showing a single cell of a fuel cell stack according to one embodiment. [Figure 2] Figure 2 is a plan view showing the cathode-side separator in Figure 1. [Figure 3] Figure 3 is a cross-sectional view along line 3-3 in Figure 2, and is a cross-sectional view centered on the cathode-side separator and the anode-side separator of another single cell adjacent to the single cell of the same cathode-side separator. [Figure 4] Figure 4 is a cross-sectional view along line 4-4 in Figure 2. [Figure 5] Figure 5 is a cross-sectional view showing an example of a modified protrusion. [Modes for carrying out the invention]

[0010] An embodiment of a fuel cell separator and fuel cell stack will be described below with reference to Figures 1 to 4. Note that, for the sake of clarity, some components in each drawing may be exaggerated or simplified, and therefore the dimensional ratios of each component may differ from those of the actual components.

[0011] As shown in Figure 1, the fuel cell stack is formed by stacking multiple single cells 90. <Single cell 90> The single cell 90 comprises a membrane electrode gas diffusion layer assembly (hereinafter referred to as the power generation unit 10), an electrically insulating frame member 20 surrounding the power generation unit 10, and a cathode-side separator 30 and an anode-side separator 40 sandwiching the power generation unit 10 and the frame member 20. The single cell 90 is rectangular in shape as a whole.

[0012] In the following explanation, the stacking direction of multiple single cells 90 will be described as the first direction X. Furthermore, the long and short sides of the single cell 90 will be described as the second direction Y and the third direction Z, respectively.

[0013] Each cell 90 has supply-side manifold holes 94, 95, and 96 for introducing fuel gas, refrigerant, and oxidizer gas into the cell 90, respectively. The cell 90 also has discharge-side manifold holes 97, 98, and 99 for discharging the fuel gas, refrigerant, and oxidizer gas from within the cell 90 to the outside, respectively.

[0014] The supply-side manifold holes 94, 95, 96 and the discharge-side manifold holes 97, 98, 99 penetrate the single cell 90 in the first direction X. The supply-side manifold holes 94 and the discharge-side manifold holes 98, 99 are located on one side of the single cell 90 in the second direction Y (left side in Figure 1). The discharge-side manifold hole 97 and the supply-side manifold holes 95, 96 are located on the other side of the single cell 90 in the second direction Y (right side in Figure 1). The supply-side manifold holes 94 and the discharge-side manifold holes 98, 99 are spaced apart from each other in the third direction Z. The discharge-side manifold holes 97 and the supply-side manifold holes 95, 96 are spaced apart from each other in the third direction Z.

[0015] <Power generation unit 10> As shown in Figure 1, the power generation unit 10 has a solid polymer electrolyte membrane (hereinafter referred to as the electrolyte membrane) (not shown) and electrodes 11 and 12 provided on both sides of the electrolyte membrane. In this embodiment, the electrode bonded to one side (upper side in Figure 1) of the electrolyte membrane (not shown) in the first direction X is the cathode electrode 11. The electrode bonded to the other side (lower side in Figure 1) of the electrolyte membrane in the first direction X is the anode electrode 12. The electrodes 11 and 12 have a catalyst layer (not shown) bonded to the electrolyte membrane and a gas diffusion layer (not shown) bonded to the catalyst layer.

[0016] <Frame member 20> The frame member 20 is provided between the cathode side separator 30 and the anode side separator 40. The frame member 20 is substantially rectangular plate-shaped in plan view and long in the second direction Y. The frame member 20 is formed of, for example, a synthetic resin material.

[0017] The frame member 20 has supply side manifold holes 24, 25, 26 that respectively constitute supply side manifold holes 94, 95, 96, and discharge side manifold holes 27, 28, 29 that respectively constitute discharge side manifold holes 97, 98, 99.

[0018] The frame member 20 has an opening 21 at the center. The peripheral edge of the power generation unit 10 is joined to the inner peripheral edge of the opening 21 from one side in the first direction X (the upper side in FIG. 1). <Cathode side separator 30> As shown in FIG. 1, the cathode side separator 30 is disposed to face the cathode electrode 11 of the power generation unit 10. The cathode side separator 30 has a base material made of a metal such as stainless steel and a conductive layer covering the surface of the base material. The base material of the cathode side separator 30 is formed by press molding.

[0019] The cathode side separator 30 has supply side manifold holes 34, 35, 36 that respectively constitute supply side manifold holes 94, 95, 96, and discharge side manifold holes 37, 38, 39 that respectively constitute discharge side manifold holes 97, 98, 99.

[0020] The cathode side separator 30 has a first surface 30a that overlaps with the frame member 20 and the power generation unit 10, and a second surface 30b that is the surface opposite to the first surface 30a. The cathode side separator 30 has a plurality of groove flow paths 50 through which an oxidant gas flows and a plurality of cooling flow paths 58 through which a refrigerant flows. The groove flow paths 50 are provided on the first surface 30a. The cooling flow paths 58 are provided on the second surface 30b.

[0021] In FIG. 1, the outer edges of the portions where the plurality of groove flow paths 50 are formed and the outer edges of the portions where the plurality of cooling flow paths 58 are formed are respectively shown in a simplified manner. <Anode-side separator 40> As shown in Figure 1, the anode-side separator 40 is positioned opposite the anode electrode 12 of the power generation unit 10. The anode-side separator 40 has a metal substrate such as stainless steel and a conductive layer covering the surface of the substrate. The substrate of the anode-side separator 40 is formed by press molding.

[0022] The anode-side separator 40 has supply-side manifold holes 44, 45, 46 and discharge-side manifold holes 47, 48, 49, respectively, which constitute supply-side manifold holes 94, 95, 96 and discharge-side manifold holes 97, 98, 99.

[0023] The anode-side separator 40 has a first surface 40a that overlaps with the frame member 20 and the power generation unit 10, and a second surface 40b that is opposite to the first surface 40a. The anode-side separator 40 has a plurality of grooved passages 60 through which fuel gas flows and a plurality of cooling passages 68 through which refrigerant flows. The grooved passages 60 are provided on the first surface 40a. The cooling passages 68 are provided on the second surface 40b.

[0024] Figure 1 shows a simplified representation of the outer edges of the portion where multiple groove channels 60 are formed and the outer edges of the portion where multiple cooling channels 68 are formed in the anode-side separator 40.

[0025] Next, the configuration of the cathode-side separator 30 will be explained in detail. Figure 2 shows the cathode-side separator 30 from Figure 1 inverted vertically. As shown in Figure 2, the multiple grooved passages 50 connect the supply-side manifold hole 36 and the discharge-side manifold hole 39. Ribs 56 are provided between the grooved passages 50 (see Figure 3). The grooved passages 50 have multiple main passages 51, multiple supply-side connecting passages 52, and multiple discharge-side connecting passages 53. The main passages 51 face the power generation unit 10. The multiple supply-side connecting passages 52 connect the supply-side manifold hole 36 to the multiple main passages 51, respectively. The multiple discharge-side connecting passages 53 connect the multiple main passages 51 to the discharge-side manifold hole 39, respectively. Therefore, the oxidizer gas is supplied from the supply-side manifold hole 36 to the main passages 51 through the supply-side connecting passages 52. The oxidizer gas flowing through the main passages 51 is discharged to the discharge-side manifold hole 39 through the discharge-side connecting passages 53.

[0026] Here, the supply-side connecting channel 52 and the discharge-side connecting channel 53 are arranged point-symmetrically with respect to the center C in the planar direction of the cathode-side separator 30. For this reason, the configuration of the discharge-side connecting channel 53 will be described later, and the configuration of the supply-side connecting channel 52 may be omitted.

[0027] As shown in Figure 2, a projection 54 is provided in a portion of the discharge-side connection channel 53 in the direction of extension, projecting toward the power generation unit 10. The projection 54 is provided in both the supply-side connection channel 52 and the discharge-side connection channel 53. The projection 54 is provided throughout the width direction of the discharge-side connection channel 53. The projection 54 is provided in all discharge-side connection channels 53. In this embodiment, the projection 54 is located on a virtual line V extending along the third direction Z.

[0028] Figure 3 shows a cooling channel 78 formed by the cathode-side separator 30 and the anode-side separator 40 of another single cell 90 (hereinafter referred to as single cell 90B) adjacent to the single cell 90 (hereinafter referred to as single cell 90A) having the cathode-side separator 30.

[0029] The cooling channel 58 of the cathode-side separator 30 is located between adjacent groove channels 50. The cooling channel 68 of the anode-side separator 40 is located between adjacent groove channels 60.

[0030] A cooling channel 78 is formed by the cooling channel 58 of the cathode-side separator 30 and the cooling channel 68 of the anode-side separator 40. As shown in Figures 3 and 4, the second surface 30b of the cathode-side separator 30 is provided with a groove 55 formed by a protrusion 54. The groove 55 connects adjacent cooling channels 58 to each other.

[0031] As shown in Figure 4, the protrusion height of the projection 54 from the bottom surface 53a of the discharge-side connecting channel 53 is constant in the direction of extension of the discharge-side connecting channel 53. Next, the operation of this embodiment will be described.

[0032] The rigidity of the supply-side connection channel 52 and the discharge-side connection channel 53 is increased by the protrusion 54. Furthermore, as shown by the arrows in Figure 3, refrigerant flows from one adjacent cooling channel 58 to the other through the groove 55. As a result, both the cooling channels 58 and the groove 55 are cooled by the refrigerant.

[0033] Next, the effects of this embodiment will be described. (1) A portion of the supply-side connection channel 52 and the discharge-side connection channel 53 in the direction of extension of the connection channels is provided with a projection 54 that protrudes toward the power generation section 10.

[0034] With this configuration, the above-mentioned effects are achieved, which suppresses warping of the cathode-side separator 30. (2) The protrusion 54 is provided over the entire width of the supply-side connection channel 52 and the discharge-side connection channel 53.

[0035] With this configuration, the rigidity of the supply-side connecting channel 52 and the discharge-side connecting channel 53 is further increased by the protruding portion 54. Therefore, warping of the cathode-side separator 30 can be further suppressed.

[0036] (3) The protruding portion 54 is provided in all connection passages that constitute the supply-side connection passage 52 and the discharge-side connection passage 53. With this configuration, the rigidity of each of the supply-side connecting channel 52 and the discharge-side connecting channel 53 is increased by the respective protrusions 54. Therefore, warping of the cathode-side separator 30 can be further suppressed.

[0037] (4) The protrusions 54 are provided in both the supply-side connection channel 52 and the discharge-side connection channel 53. With this configuration, the rigidity of both the supply-side connecting channel 52 and the discharge-side connecting channel 53 is increased by the protrusion 54. Therefore, warping of the cathode-side separator 30 can be further suppressed.

[0038] (5) The supply-side connecting channel 52 and the discharge-side connecting channel 53 are arranged point-symmetrically with respect to the center C in the planar direction of the cathode-side separator 30. With this configuration, the rigidity of the cathode-side separator 30 can be increased in a well-balanced manner around the center C in the planar direction of the cathode-side separator 30. Therefore, warping of the cathode-side separator 30 can be further suppressed.

[0039] (6) The cooling channel 58 of the cathode-side separator 30 is located between adjacent connecting channels 52 and 53. The protrusion 54 is provided over the entire width of the connecting channels 52 and 53. The second surface 30b is provided with a groove 55 formed by the protrusion 54, which connects adjacent cooling channels 58.

[0040] With this configuration, the protrusions 54 provided in the connecting channels 52 and 53 form grooves 55 that connect adjacent cooling channels 58 to each other. The refrigerant flowing through the cooling channels 58 flows through the grooves 55. As a result, the surface area of ​​the cooling channels 58 increases by the amount of the grooves 55. This improves the cooling efficiency of the fuel cell stack.

[0041] <Example of changes> This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0042] As shown in Figure 5, the protrusion height of the protrusion 540 may be increased towards the downstream side in the flow direction of the oxidizing gas. In this case, the increase in pressure loss of the oxidizing gas caused by the provision of the protrusion 540 can be suppressed.

[0043] In this embodiment, a gap is provided between the groove 55 of the cathode-side separator 30 and the anode-side separator 40 of a single cell 90B that is separate from the single cell 90A having the cathode-side separator 30, but this is not limited to this. The portion of the anode-side separator 40 of the other single cell 90B that faces the groove 55 may be brought into contact with the entire bottom surface of the groove 55 to eliminate the gap.

[0044] In this embodiment, the supply-side connecting channel 52 and the discharge-side connecting channel 53 are arranged point-symmetrically with respect to the center C in the planar direction of the cathode-side separator 30, but this is not limited to this configuration. The supply-side connecting channel 52 and the discharge-side connecting channel 53 may be arranged asymmetrically with respect to the center C in the planar direction of the cathode-side separator 30.

[0045] The protruding portion 54 of either the supply-side connection channel 52 or the discharge-side connection channel 53 can be omitted. Even in this case, the rigidity of the connection channel in which the protruding portion 54 is provided can be increased.

[0046] In this embodiment, protrusions 54 are provided on all of the multiple supply-side connection channels 52, but this is not limited to this. It is sufficient that the protrusions 54 are provided on at least one of the multiple supply-side connection channels 52. Even in this case, the rigidity of the supply-side connection channel 52 on which the protrusions 54 are provided can be increased. The same applies to the discharge-side connection channel 53.

[0047] In this embodiment, the protrusion 54 is provided over the entire width of the supply-side connection channel 52, but it is not limited to this. The protrusion 54 may be provided over only a part of the width of the supply-side connection channel 52. The same applies to the discharge-side connection channel 53.

[0048] In addition to, or instead of, the cathode-side separator 30, the anode-side separator 40 may be provided with a protrusion 54. <Note> The above embodiment includes the configuration described in the following appendix.

[0049] [Note 1] A fuel cell separator arranged opposite the power generation section of a fuel cell, comprising: a plurality of main passages through which a reaction gas flows, facing the power generation section; supply-side manifold holes for supplying the reaction gas toward the plurality of main passages; discharge-side manifold holes for discharging the reaction gas from the main passages; a plurality of supply-side connecting passages connecting the supply-side manifold holes to the plurality of main passages; and a plurality of discharge-side connecting passages connecting the discharge-side manifold holes to the plurality of main passages, wherein a projection is provided in the extending direction of at least one of the supply-side connecting passages and the discharge-side connecting passages, projecting toward the power generation section.

[0050] [Note 2] The fuel cell separator according to [Note 1], wherein the protrusion is provided over the entire width of at least one of the connecting channels. [Note 3] The fuel cell separator according to [Note 1] or [Note 2], wherein the protruding portion is provided in all connection passages that constitute at least one of the supply-side connection passage and the discharge-side connection passage.

[0051] [Note 4] The fuel cell separator according to any one of [Note 1] to [Note 3], wherein the protruding portion is provided in both the supply-side connection channel and the discharge-side connection channel. [Note 5] The protruding portion is provided in all connection passages that constitute both the supply-side connection passage and the discharge-side connection passage, and the supply-side connection passage and the discharge-side connection passage are arranged point-symmetrically with respect to the center in the planar direction of the fuel cell separator, as described in [Note 4].

[0052] [Note 6] A fuel cell stack formed by stacking a plurality of single cells, each having a power generation unit and a first separator and a second separator sandwiching the power generation unit, wherein the first separator is adjacent to the second separator of a single cell other than the single cell having the first separator, and at least one of the separators, the first separator and the second separator of the other single cell, is a fuel cell separator as described in any one of [Note 1] to [Note 5], and the at least one separator has a cooling channel through which a refrigerant flows on the side opposite to the side on which the main flow path is provided, the cooling channel is located between at least one adjacent connecting channel, the protrusion is provided over the entire width of the at least one connecting channel, and the opposite side is provided with a groove formed by the protrusion that connects the adjacent cooling channels. [Explanation of Symbols]

[0053] 10…Membrane electrode gas diffusion layer assembly (power generation section) 11… Cathode electrode 12... Anode electrode 20…Frame members 21…Opening 24-26... Supply side manifold holes 27-29... Discharge side manifold holes 30... Cathode-side separator 30a...Side 1 30b…Second side 34-36... Supply side manifold holes 37-39... Discharge side manifold holes 40... Anode-side separator 40a...Page 1 40b…Second side 44-46... Supply side manifold holes 47-49... Exhaust side manifold holes 50...Groove channel 51…Main channel 52... Supply side connection channel 53... Discharge side connection channel 53a...Bottom 54,540…Protrusion 55… recessed groove 56... Rib 58…Cooling channel 60…Groove channel 68…Cooling channel 78…Cooling channel 90, 90A, 90B… Single cell 94-96... Supply side manifold holes 97-99... Exhaust side manifold holes

Claims

1. A fuel cell separator positioned opposite the power generation section of a fuel cell, Opposite the power generation section are a plurality of main channels through which the reaction gas flows, A supply-side manifold hole for supplying the reaction gas to multiple main flow channels, A discharge-side manifold hole for discharging the reaction gas from the main flow path, Multiple supply-side connecting passages that connect the supply-side manifold hole and the multiple main passages, It has a plurality of discharge-side connecting passages that connect the discharge-side manifold hole and the plurality of main passages, A portion of the supply-side connection channel and the discharge-side connection channel is provided with a projection that extends toward the power generation section, in the direction of extension of at least one of the connection channels. Separator for fuel cells.

2. The protrusion is provided over the entire width of at least one of the connecting channels. A fuel cell separator according to claim 1.

3. The aforementioned protrusions are provided in all connection passages that constitute at least one of the supply-side connection passage and the discharge-side connection passage. A fuel cell separator according to claim 1.

4. The aforementioned protrusions are provided in both the supply-side connection channel and the discharge-side connection channel. A fuel cell separator according to claim 1.

5. The aforementioned protrusions are provided in all connection passages that constitute both the supply-side connection passage and the discharge-side connection passage. The supply-side connection channel and the discharge-side connection channel are arranged point-symmetrically with respect to the center in the planar direction of the fuel cell separator. A fuel cell separator according to claim 4.

6. A fuel cell stack formed by stacking multiple single cells, each having a power generation unit and a first separator and a second separator sandwiching the power generation unit, The first separator is adjacent to the second separator of a single cell that is different from the single cell having the first separator. At least one of the first separator and the second separator of the other single cell is a fuel cell separator according to any one of claims 1 to 5, The at least one of the separators has a cooling channel through which the refrigerant flows on the side opposite to the side on which the main flow path is provided. The cooling channel is located between at least one of the adjacent connecting channels. The aforementioned protrusion is provided over the entire width of at least one of the connecting channels, On the opposite side, grooves are provided, formed by the protrusions, that connect adjacent cooling channels. Fuel cell stack.

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