End plate for fuel battery and fuel battery with the same

Abstract

To provide an end plate for a fuel battery, capable of efficiently draining generation water generated in a fluid path penetrating a fuel battery lamination body to an external part.SOLUTION: In a fuel battery 1 having a fuel battery lamination body 3 including a plurality of fuel battery cells 2a to be laminated, an end plate for a fuel battery 6a arranged at one end in a lamination direction of the fuel battery lamination body 3 includes: an inner side connection port 13b that is an inner side connection port 13b formed on a first surface 16 of the end plate for the fuel battery 6a, and connects the fuel battery lamination body 3 to an outlet side opening 8a of a fluid path 8 penetrated in a lamination direction; an external side connection port 13a that is an external connection port 13a that is formed at a second surface 17 which is different from a first surface 16 in the end plate for the fuel battery 6a, and is connected to an external part pipe; and a penetration hole 13 that communicates the inner side connection port 13b and the external side connection port 13a. A lower part surface 13c in an inner peripheral surface forming the penetration hole 13 is inclined downward as going from the inner side connection port 13b toward the external connection port 13a.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an end plate for a fuel cell and a fuel cell including the end plate. [Background technology]

[0002] The fuel cell described in Patent Document 1 is known as an example of a fuel cell in which a fuel cell stack (fuel cell laminate) in which multiple fuel cells are stacked is sandwiched between a pair of end plates. The fuel cell described in Patent Document 1 includes a gas supply manifold for supplying fuel gas or oxidant gas from the outside to each fuel cell, and a drainage channel for discharging generated water accumulated in the gas supply manifold to the outside. The gas supply manifold is a fluid passage formed penetrating from one end plate in the stacking direction, and the drainage channel is formed penetrating from the other end plate to the gas supply manifold. The bottom surface of the gas supply manifold is inclined downward toward the drainage channel.

[0003] According to the fuel cell described in Patent Document 1, if water droplets (generated water) occur in the gas supply manifold of the fuel cell stack, the generated water can be efficiently discharged outside the stack, thereby preventing unstable power generation or reduced power generation performance caused by the generated water in the manifold on the gas supply side impeding gas supply. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-141639 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the fuel cell described in Patent Document 1, the bottom surface of the gas supply manifold is inclined downward toward the drainage channel, so even if the generated water generated in the gas supply manifold can be discharged to the drainage channel formed in the other end plate, it is unclear whether the generated water can be efficiently discharged from the drainage channel to the outside. In addition, a separate member is required to provide an inclination to the bottom surface of the gas supply manifold, which increases the number of parts. In addition, if the bottom surface of the gas supply manifold is inclined, the bottom surface of the inclined gas supply manifold is determined to be downward in the vertical direction, which is the direction of gravity in the fuel cell, so the loading direction of the fuel cell cannot be freely changed. Therefore, when changing the loading direction of the fuel cell, the specifications of the fuel cell stack had to be changed to match the loading direction of the fuel cell.

[0006] Therefore, the present invention aims to provide an end plate for a fuel cell that can efficiently discharge water generated in a fluid passage penetrating a fuel cell stack to the outside with a simple configuration and can easily adapt to the stacking direction of the fuel cell, and a fuel cell equipped with such an end plate. [Means for solving the problem]

[0007] One aspect of the present invention is a fuel cell comprising a fuel cell stack including a plurality of stacked fuel cell cells, the fuel cell end plate being arranged at one end in a stacking direction of the fuel cell stack, the fuel cell end plate having an inner connection port formed on a first surface of the fuel cell end plate, the inner connection port connecting to an outlet opening of a fluid passage penetrating the fuel cell stack in the stacking direction, and an outer connection port formed on a second surface of the fuel cell end plate different from the first surface, the outer connection port connecting to an external piping, and a through hole communicating between the inner connection port and the outer connection port, the lower surface of the inner circumferential surface forming the through hole being inclined downwardly as it goes from the inner connection port to the outer connection port. Effect of the Invention

[0008] According to the present invention, it is possible to provide an end plate for a fuel cell that can efficiently discharge to the outside water generated in a fluid passage penetrating a fuel cell stack with a simple configuration and can easily adapt to the stacking direction of the fuel cell, and a fuel cell equipped with the end plate. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a fuel cell including an end plate for a fuel cell according to an embodiment of the present invention. [Diagram 2] 1 is a side view of a fuel cell including an end plate for a fuel cell according to an embodiment of the present invention. [Diagram 3] 1 is a front view of a fuel cell including an end plate for a fuel cell according to an embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along line AA in FIG. [Diagram 5] FIG. 5 is a partially enlarged view of FIG. [Figure 6] 1A and 1B are perspective views showing a part of an end plate for a fuel cell according to the present embodiment, in which (a) is a perspective view seen from the front side, and (b) is a perspective view showing a cross section of (a). [Figure 7] 11A and 11B are perspective views showing an end plate for a fuel cell according to another embodiment, where (a) is a perspective view seen from the side, (b) is a perspective view seen from the front, and (c) is a cross-section of the perspective view seen from the side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the fuel cell end plate according to the present embodiment and a fuel cell using the end plate for the fuel cell will be described with reference to the attached drawings. In addition, in Figs. 1 to 6, unless otherwise specified, the fuel cell 1 is placed in a mounted state, the upper side of the paper indicates the upper side of the fuel cell 1, and the lower side of the paper indicates the lower side, which is the direction of gravity of the fuel cell 1. Fig. 1 is a perspective view of a fuel cell using the end plate for the fuel cell according to the present embodiment, and Fig. 2 is a side view of a fuel cell using the end plate for the fuel cell according to the present embodiment. In addition, the arrows in each figure indicate directions, and in this embodiment, the Z direction of the arrow is the front-rear direction, the Z direction side is the front side, the opposite side of the Z direction side of the arrow is the rear side, the X direction of the arrow is the left-right direction, the X direction side of the arrow is the right side side, the opposite side of the X direction side of the arrow is the left side side, the Y direction of the arrow is the up-down direction, the Y direction side of the arrow is the upper side, and the opposite side of the Y direction side of the arrow is the lower side.

[0011] A fuel cell 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view of the fuel cell 1, and FIG. 2 is a right side view of the fuel cell 1. The fuel cell 1 is a cell that generates electricity by reacting hydrogen gas as a fuel gas with air as an oxidant gas. As shown in FIGS. 1 and 2, the fuel cell 1 has a fuel cell stack 3 including a fuel cell stack 2 in which a plurality of fuel cells 2a are stacked, and a pair of aluminum fuel cell end plates 6a, 6b that sandwich the fuel cell stack 3 from both ends (hereinafter, simply referred to as end plates). The fuel cell stack 3 has the fuel cell stack 2, conductive current collector plates 4 that are arranged at both ends of the fuel cell stack 2 and collect the generated electricity, and insulating plates 5 that are arranged on the outside of each of the current collector plates 4 arranged at both ends of the fuel cell stack 2. The fuel cell 1 is arranged in the order of the end plates 6a, 6b, the insulating plates 5, the current collector plates 4, and the fuel cell stack 2 from the outside. A pair of end plates 6a, 6b, an insulating plate 5, a current collector plate 4, and a fuel cell stack 2 are fastened by a fastening rod (not shown) penetrating the fuel cell stack 2, and a fastening pressure is applied to the stacked fuel cell cells 2a to clamp them. The fuel cell cell 2a is configured by sandwiching an electrode electrolyte assembly, which is configured by sandwiching a pair of electrodes and an electrolyte membrane, between a pair of separators, as in the conventional case. Of the pair of end plates 6a, 6b, the end plate 6a is disposed at one end of the fuel cell stack 3, and of the pair of end plates 6a, 6b, the end plate 6b is disposed at the other end of the fuel cell stack 3. In addition, in Figs. 1 and 2, a part of the stacked fuel cell cells 2a is omitted for ease of understanding. In this embodiment, the end plates 6a, 6b are made of aluminum, but they may be made of stainless steel or resin.

[0012] Although details will be described later, the fuel cell stack 3 is formed with six fluid passages that penetrate the fuel cell stack 3 in the stacking direction. The six fluid passages are a fuel gas supply passage 7 (see FIG. 4) and a fuel gas discharge passage (not shown), an oxidant gas supply passage and an oxidant gas discharge passage 8 (not shown) (see FIG. 4), and a coolant supply passage and a coolant discharge passage 9 (not shown) (see FIG. 4). Each of the six fluid passages communicates with external piping via a supply hole and a discharge hole (described later) that are formed in an end plate 6a that is arranged at one end of the fuel cell stack 3 in the stacking direction.

[0013] 1 and 2, the fuel gas supply passage 7, the oxidant gas discharge passage 8, and the coolant discharge passage 9 are disposed on the left side of the fuel cell stack 3, while the oxidant gas supply passage, the fuel gas discharge passage, and the coolant supply passage are disposed on the right side of the fuel cell stack 3. The fuel gas supply passage 7 is disposed in the upper stage of the fuel cell stack 3, the coolant discharge passage 9 is disposed in the middle stage of the fuel cell stack 3, and the oxidant gas discharge passage 8 is disposed in the lower stage of the fuel cell stack 3. The oxidant gas supply passage is disposed in the upper stage of the fuel cell stack 3, the coolant supply passage is disposed in the middle stage of the fuel cell stack 3, and the fuel gas discharge passage is disposed in the lower stage of the fuel cell stack 3.

[0014] The fuel gas supply passage 7 is used to supply fuel gas from the outside of the fuel cell 1 to the fuel cell stack 2, and the fuel gas discharge passage is used to discharge fuel gas not used in the fuel cell stack 2 from the fuel cell stack 2 to the outside. Similarly, the oxidant gas supply passage is used to supply oxidant gas from the outside of the fuel cell 1 to the fuel cell stack 2, and the oxidant gas discharge passage 8 is used to discharge air, which is the oxidant gas used in the power generation reaction, from the fuel cell stack 2 to the outside. In addition, the cooling medium supply passage is used to supply a cooling medium from the outside of the fuel cell 1 to the fuel cell stack 2 in order to suppress a temperature rise due to heat generation in the fuel cell stack 2, and the cooling medium discharge passage 9 is used to discharge the cooling medium that has recovered heat from the fuel cell stack 2. For example, cooling water is used as the cooling medium. In the following, the fuel gas, the oxidant gas, and the cooling medium may be simply referred to as fluids.

[0015] In a cross section perpendicular to the stacking direction of the fuel cell stack 3 (hereinafter referred to as a cross section), the fuel gas supply passage 7 and the fuel gas discharge passage are vertically elongated rectangular. Similarly, in a cross section, the oxidant gas supply passage and the oxidant gas discharge passage 8 are vertically elongated rectangular. In a cross section, the cooling medium supply passage and the cooling medium discharge passage 9 are rectangular and substantially square. The four corners of the rectangular shape in the cross section of these fluid passages are rounded. By making the cross section of each fluid passage substantially rectangular, a larger power generation area of ​​the fuel cell stack 2 can be secured than when the cross section is circular. In the following, the fuel gas supply passage 7, the fuel gas discharge passage, the oxidant gas supply passage, the oxidant gas discharge passage 8, the cooling medium supply passage, and the cooling medium discharge passage 9 may be simply referred to as fluid passages, the fuel gas supply passage 7, the oxidant gas supply passage, and the cooling medium supply passage may be simply referred to as supply passages, and the fuel gas discharge passage, the oxidant gas discharge passage 8, and the cooling medium discharge passage 9 may be simply referred to as discharge passages.

[0016] Next, the end plate 6a arranged at one end of the fuel cell stack 3 in the stacking direction will be described with reference to FIG. 3. The end plate 6a is a rectangular parallelepiped plate having an inner end face 16 as a first face connected to one end face of the fuel cell stack 3, an outer end face 17 which is the opposite face facing the inner end face 16, and an outer peripheral face 18 arranged between the inner end face 16 and the outer end face 17. The outer peripheral face 18 is composed of an upper side face 18a on the upper side, a lower side face 18b on the lower side, a left side face 18c arranged on the left side when the fuel cell 1 is viewed from the front, and a right side face 18d arranged on the right side when the fuel cell 1 is viewed from the front. The outer end face 17 is the second face in the present invention. The outer end face 17 is also the face opposite the inner end face 16 in the thickness direction of the end plate 6a.

[0017] The end plate 6a has six through holes formed therein, which are connected to the above-mentioned fluid passages, that is, the fuel gas supply passage 7 and the fuel gas discharge passage, the oxidant gas supply passage and the oxidant gas discharge passage 8, and the cooling medium supply passage and the cooling medium discharge passage 9. The through holes penetrate in the Z direction (front-rear direction) of the arrow. On the other hand, of the pair of end plates 6a and 6b, the end plate 6b disposed at the other end of the fuel cell stack 3 does not have through holes formed therein that connect to the openings of the fluid passages. In the front view of FIG. 3, a fuel gas supply hole 10 is formed in the upper left part of the end plate 6a as a through hole connecting to the fuel gas supply passage 7. A cooling medium discharge hole 15 is formed in the middle left part of the end plate 6a as a through hole connecting to the cooling medium discharge passage 9. An oxidant gas discharge hole 13 is formed in the lower left part of the end plate 6a as a through hole connecting to the oxidant gas discharge passage 8. An oxidant gas supply hole 12 is formed in the upper right part of the end plate 6a as a through hole connecting to the oxidant gas supply passage. A cooling medium supply hole 14 is formed in the middle of the right side of the end plate 6a as a through hole connecting to the cooling medium supply passage. A fuel gas discharge hole 11 is formed in the lower right side of the end plate 6a as a through hole connecting to the fuel gas discharge passage. Hereinafter, the fuel gas supply hole 10, the fuel gas discharge hole 11, the oxidant gas supply hole 12, the oxidant gas discharge hole 13, the cooling medium supply hole 14, and the cooling medium discharge hole 15 may be simply referred to as through holes, the fuel gas supply hole 10, the oxidant gas supply hole 12, and the cooling medium supply hole 14 may be simply referred to as supply holes, and the fuel gas discharge hole 11, the oxidant gas discharge hole 13, and the cooling medium discharge hole 15 may be simply referred to as discharge holes.

[0018] The fuel gas supply hole 10 is used to supply fuel gas from the outside of the fuel cell 1 to the fuel gas supply passage 7 formed in the fuel cell stack 3. The cooling medium discharge hole 15 is used to discharge the cooling medium discharged from the cooling medium discharge passage 9 formed in the fuel cell stack 3 to the outside of the fuel cell 1. The oxidant gas discharge hole 13 is used to discharge the oxidant gas discharged from the cold oxidant gas discharge passage 8 formed in the fuel cell stack 3 to the outside of the fuel cell 1. The oxidant gas supply hole 12 is used to supply the oxidant gas from the outside of the fuel cell 1 to the oxidant gas supply passage formed in the fuel cell stack 3. The cooling medium supply hole 14 is used to supply the cooling medium from the outside of the fuel cell 1 to the cooling medium supply passage formed in the fuel cell stack 3. The fuel gas discharge hole 11 is used to discharge the fuel gas discharged from the fuel gas discharge passage formed in the fuel cell stack 3 to the outside of the fuel cell 1.

[0019] The fuel gas supply hole 10, which is a through hole formed in the end plate 6a, has a fuel gas supply hole outer opening 10a, which is an opening formed in the outer end surface 17 of the end plate 6a, and a fuel gas supply hole inner opening 10b, which is an opening formed in the inner end surface 16 of the end plate 6a. The fuel gas supply hole outer opening 10a is an opening to which an external piping (not shown) is connected. The fuel gas supply hole inner opening 10b is an opening connected to the inlet side opening 7a of the fuel gas supply passage 7 formed in the fuel cell stack 3. The cooling medium discharge hole 15, which is a through hole formed in the end plate 6a, has a cooling medium discharge hole outer opening 15a, which is an opening formed in the outer end surface 17 of the end plate 6a, and a cooling medium discharge hole inner opening 15b, which is an opening formed in the inner end surface 16 of the end plate 6a. The cooling medium discharge hole outer opening 15a is an opening to which an external piping (not shown) is connected. The cooling medium discharge hole inner opening 15b is an opening connected to the outlet side opening 9a of the cooling medium discharge passage 9 formed in the fuel cell stack 3. The oxidant gas discharge hole 13, which is a through hole formed in the end plate 6a, has an oxidant gas discharge hole outer opening 13a, which is an opening formed in the outer end face 17 of the end plate 6a, and an oxidant gas discharge hole inner opening 13b, which is an opening formed in the inner end face 16 of the end plate 6a. The oxidant gas discharge hole outer opening 13a is an opening to which an external piping (not shown) is connected. The oxidant gas discharge hole inner opening 13b is an opening connected to the outlet side opening 8a of the oxidant gas discharge passage 8 formed in the fuel cell stack 3.

[0020] The oxidant gas supply hole 12, which is a through hole formed in the end plate 6a, has an oxidant gas supply hole outer opening 12a, which is an opening formed in the outer end face 17 of the end plate 6a, and an oxidant gas supply hole inner opening 12b, which is an opening formed in the inner end face 16 of the end plate 6a. The oxidant gas supply hole outer opening 12a is an opening to which an external piping (not shown) is connected. The oxidant gas supply hole inner opening 12b is an opening connected to an inlet side opening of an oxidant gas supply passage formed in the fuel cell stack 3. The coolant supply hole 14, which is a through hole formed in the end plate 6a, has a coolant supply hole outer opening 14a, which is an opening formed in the outer end face 17 of the end plate 6a, and a coolant supply hole inner opening 14b, which is an opening formed in the inner end face 16 of the end plate 6a. The coolant supply hole outer opening 14a is an opening to which an external piping (not shown) is connected. The coolant supply hole inner opening 14b is an opening connected to an inlet side opening of a coolant supply passage formed in the fuel cell stack 3. The fuel gas exhaust hole 11, which is a through hole formed in the end plate 6a, has a fuel gas exhaust hole outer opening 11a, which is an opening formed in the outer end surface 17 of the end plate 6a, and a fuel gas exhaust hole inner opening 11b, which is an opening formed in the inner end surface 16 of the end plate 6a. The fuel gas exhaust hole outer opening 11a is an opening to which an external pipe (not shown) is connected. The fuel gas exhaust hole inner opening 11b is an opening that connects to an outlet side opening of a fuel gas exhaust passage formed in the fuel cell stack 3. The inlet side opening is the opening on the side into which the fluid flowing through the supply passage flows in. The outlet side opening is the opening on the side from which the fluid flowing through the exhaust passage flows out.

[0021] The fuel gas supply hole outer opening 10a, the coolant discharge hole outer opening 15a, the oxidant gas discharge hole outer opening 13a, the oxidant gas supply hole outer opening 12a, the coolant supply hole outer opening 14a, and the fuel gas discharge hole outer opening 11a are each circular in shape. On the other hand, the shape and dimensions of the fuel gas supply hole inner opening 10b are the same as the shape and dimensions of the cross section of the fuel gas supply passage 7, and are substantially rectangular. Similarly, the shape and dimensions of the coolant discharge hole inner opening 15b are the same as the shape and dimensions of the cross section of the coolant discharge passage 9, and are substantially rectangular. The shape and dimensions of the oxidant gas discharge hole inner opening 13b are the same as the shape and dimensions of the cross section of the oxidant gas discharge passage 8, and are substantially rectangular. The shape and dimensions of the oxidant gas supply hole inner opening 12b are the same as the shape and dimensions of the cross section of the oxidant gas supply passage, and are substantially rectangular. The shape and dimensions of the coolant supply hole inner opening 14b are the same as the shape and dimensions of the cross section of the coolant supply passage, and are substantially rectangular. The shape and dimensions of the fuel gas discharge hole inner opening 11b are the same as the shape and dimensions of the cross section of the fuel gas discharge passage, and are substantially rectangular.

[0022] Next, the internal structure of the fuel cell 1 will be described with reference to Figs. 4, 5, 6(a) and 6(b). Fig. 4 is an AA cross-sectional view of Fig. 3, and is a partial cross-sectional view of the fuel cell 1. Fig. 5 is an enlarged cross-sectional view of the partial cross-sectional view of Fig. 4, and Figs. 6(a) and 6(b) are perspective views showing a part of the end plate 6a. In the fuel cell stack 3, a fuel gas supply passage 7, a cooling medium discharge passage 9 and an oxidant gas discharge passage 8 are arranged, which penetrate the fuel cell stack 3 in the stacking direction, in that order from above. In the end plate 6a, a fuel gas supply hole 10 communicating with the fuel gas supply passage 7, a cooling medium discharge hole 15 communicating with the cooling medium discharge passage 9 and an oxidant gas discharge hole 13 communicating with the oxidant gas discharge passage 8 are arranged, in that order from above, in the same direction as the stacking direction of the fuel cell stack 3. A fuel gas supply hole inner opening 10b formed on the inner end surface 16 of the end plate 6a in the fuel gas supply hole 10 is connected to an inlet side opening 7a of the fuel gas supply passage 7. A coolant discharge hole inner opening 15b formed in the inner end surface 16 of the end plate 6a of the coolant discharge hole 15 is connected to an outlet side opening 9a of the coolant discharge passage 9. An oxidant gas discharge hole inner opening 13b formed in the inner end surface 16 of the end plate 6a of the oxidant gas discharge hole 13 is connected to an outlet side opening 8a of the oxidant gas discharge passage 8.

[0023] Next, the structure of the oxidant gas discharge hole 13 of this embodiment will be described. The oxidant gas discharge hole outer opening 13a of the oxidant gas discharge hole 13 is disposed lower in the up-down direction than the oxidant gas discharge hole inner opening 13b. In addition, the lower surface 13c located on the lower side in the up-down direction, which is the direction of gravity, of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a formed on the outer end surface 17 of the end plate 6a. Here, the lower surface 13c is a surface that comes into contact with the water generated in the fuel cell stack 3 and flowing into the oxidant gas discharge hole 13 from the oxidant gas discharge passage 8 on the inner circumferential surface forming the oxidant gas discharge hole 13 when the fuel cell 1 is placed. Therefore, the inner circumferential surface other than the lower surface 13c of the oxidant gas discharge hole 13 does not need to be inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a. The diameter of the circular oxidant gas discharge hole outer opening 13a is determined so that the cross-sectional area in terms of fluid dynamics is the same as the area of ​​the rectangular oxidant gas discharge hole inner opening 13b. However, the area of ​​the circular oxidant gas discharge hole outer opening 13a may be larger than the area of ​​the rectangular oxidant gas discharge hole inner opening 13b.

[0024] 6(a) and 6(b), the oxidant gas discharge hole inner opening 13b is a vertically long rectangular shape, and the oxidant gas discharge hole outer opening 13a is a circular shape, but the oxidant gas discharge hole 13 is gradually deformed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. Here, gradual deformation means that the shape is gradually changed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. The oxidant gas discharge hole inner opening 13b is an inner connection port in the present invention, and the oxidant gas discharge hole outer opening 13a is an outer connection port in the present invention.

[0025] When water vapor contained in the oxidant gas condenses in the fuel cell stack 3 to generate water, the generated water reaches the oxidant gas discharge hole 13 via the oxidant gas discharge passage 8, but in the end plate 6a according to this embodiment, the lower surface 13c of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a. Therefore, the generated water flows by gravity to the oxidant gas discharge hole outer opening 13a side and is drained outside the fuel cell 1. This makes it possible to prevent a decrease in power generation performance due to accumulation of generated water.

[0026] Furthermore, in the end plate 6a according to this embodiment, the oxidant gas discharge hole 13 is gradually changed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. This reduces the energy loss of the generated water flowing through the oxidant gas discharge hole 13, making it easier to discharge the generated water and preventing a decrease in power generation performance.

[0027] In addition, the diameter of the circular oxidant gas discharge hole outer opening 13a is determined so that the hydrodynamic cross-sectional area is the same as the area of ​​the rectangular oxidant gas discharge hole inner opening 13b. This makes it possible to minimize the pressure loss of the generated water flowing through the oxidant gas discharge hole 13 and prevent a decrease in power generation performance.

[0028] In this embodiment, the lower surface 13c of the inner circumferential surface of the end plate 6a that forms the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a, so that even if the left side surface 18c of the end plate 6a in Fig. 3 must be on the gravity direction side, for example, it is only necessary to change the specifications of the end plate 6a, such as by arranging the oxidant gas discharge hole outer opening 13a on the left side surface 18c, without changing the specifications of the fuel cell stack 3, and therefore it is possible to easily accommodate the loading direction of the fuel cells 1. The mode of arranging the oxidant gas discharge hole outer opening 13a on the left side surface 18c will be described later.

[0029] In this embodiment, the oxidant gas discharge hole outer opening 13a of the oxidant gas discharge hole 13 is disposed lower than the oxidant gas discharge hole inner opening 13b in the up-down direction, but is not necessarily limited to this. Even if the oxidant gas discharge hole outer opening 13a is not disposed lower than the oxidant gas discharge hole inner opening 13b in the up-down direction, it is sufficient that the lower surface 13c located on the lower side in the up-down direction of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a. This is because the water generated in the fuel cell stack 3 and flowing into the oxidant gas discharge hole 13 through the oxidant gas discharge passage 8 flows by gravity toward the oxidant gas discharge hole outer opening 13a and can be drained outside the fuel cell 1.

[0030] In this embodiment, the diameter of the circular oxidant gas discharge hole outer opening 13a is determined so that the cross-sectional area in terms of fluid dynamics is the same as the area of ​​the rectangular oxidant gas discharge hole inner opening 13b, but this is not necessarily limited to this. Even if the area of ​​the oxidant gas discharge hole outer opening 13a is not the same as the area of ​​the oxidant gas discharge hole inner opening 13b, it is only necessary that the lower surface 13c located on the gravity direction side of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a.

[0031] Next, the cooling medium discharge hole 15 of this embodiment will be described. The cooling medium discharge hole outer opening 15a and the cooling medium discharge hole inner opening 15b of the cooling medium discharge hole 15 are at the same position in the vertical direction, and the area of ​​the cooling medium discharge hole outer opening 15a is larger than the area of ​​the rectangular cooling medium discharge hole inner opening 15b. In addition, the lower surface 15c located on the gravity direction side of the inner circumferential surface forming the cooling medium discharge hole 15 is inclined downward from the cooling medium discharge hole inner opening 15b toward the cooling medium discharge hole outer opening 15a formed on the outer end surface 17 of the end plate 6a. Here, the lower surface 15c is a surface that the cooling water that flows into the cooling medium discharge hole 15 from the cooling medium discharge passage 9 contacts on the inner circumferential surface forming the cooling medium discharge hole 15. Therefore, it is not necessary for the inner circumferential surface other than the lower surface 15c of the cooling medium discharge hole 15 to be inclined downward from the cooling medium discharge hole inner opening 15b toward the cooling medium discharge hole outer opening 15a.

[0032] 6(a) and 6(b), the cooling medium discharge hole inner opening 15b is a vertically long rectangular shape, and the cooling medium discharge hole outer opening 15a is a circular shape, but the cooling medium discharge hole 15 is gradually deformed so that there is no step between the cooling medium discharge hole inner opening 15b and the cooling medium discharge hole outer opening 15a. Here, the gradual deformation means that the shape is gradually changed so that there is no step between the cooling medium discharge hole inner opening 15b and the cooling medium discharge hole outer opening 15a. The cooling medium discharge hole inner opening 15b is the inner connection port in the present invention, and the cooling medium discharge hole outer opening 15a is the outer connection port in the present invention.

[0033] As a result, in the end plate 6a of this embodiment, the cooling medium discharge hole 15 is gradually formed so that no step is created between the cooling medium discharge hole inner opening 15b and the cooling medium discharge hole outer opening 15a. This reduces energy loss in the cooling water flowing through the cooling medium discharge hole 15, making it easier to discharge the cooling water and preventing a decrease in power generation performance.

[0034] Next, the fuel gas discharge hole 11 will be described. Although the detailed configuration of the fuel gas discharge hole 11 is not shown, the configuration of the fuel gas discharge hole 11 may be the same as that of the oxidant gas discharge hole 13 described above. That is, the lower surface located on the lower side in the vertical direction, which is the gravity direction side of the inner peripheral surface forming the fuel gas discharge hole 11, is inclined downward from the fuel gas discharge hole inner opening 11b toward the fuel gas discharge hole outer opening 11a formed on the outer end surface 17 of the end plate 6a. Here, the lower surface is a surface that contacts the water generated by condensation or the like and flowing into the fuel gas discharge hole 11 from the fuel gas discharge passage on the inner peripheral surface forming the fuel gas discharge hole 11. Therefore, the inner peripheral surface other than the lower surface of the fuel gas discharge hole 11 does not need to be inclined downward from the fuel gas discharge hole inner opening 11b toward the fuel gas discharge hole outer opening 11a.

[0035] Furthermore, the fuel gas exhaust hole inner opening 11b is a vertically long rectangular shape, and the fuel gas exhaust hole outer opening 11a is a circular shape, but the fuel gas exhaust hole 11 is gradually deformed so that no step is created between the fuel gas exhaust hole inner opening 11b and the fuel gas exhaust hole outer opening 11a. Here, gradual deformation means that the shape is gradually changed so that no step is created between the fuel gas exhaust hole inner opening 11b and the fuel gas exhaust hole outer opening 11a. The fuel gas exhaust hole inner opening 11b is an inner connection port in the present invention, and the fuel gas exhaust hole outer opening 11a is an outer connection port in the present invention.

[0036] When water vapor contained in the combustion gas condenses in the fuel cell stack 3 to generate water, the generated water reaches the fuel gas exhaust hole 11 through the fuel gas exhaust passage, but in the end plate 6a according to this embodiment, the lower surface of the inner circumferential surface forming the fuel gas exhaust hole 11 is inclined downward from the fuel gas exhaust hole inner opening 11b toward the fuel gas exhaust hole outer opening 11a. Therefore, the generated water flows by gravity to the fuel gas exhaust hole outer opening 11a side and is drained outside the fuel cell 1. This makes it possible to prevent a decrease in power generation performance due to accumulation of generated water.

[0037] Furthermore, in the end plate 6a according to this embodiment, the fuel gas discharge hole 11 is gradually changed so that no step is created between the fuel gas discharge hole inner opening 11b and the fuel gas discharge hole outer opening 11a. This reduces the energy loss of the generated water flowing through the fuel gas discharge hole 11, making it easier to discharge the generated water and preventing a decrease in power generation performance.

[0038] Next, an end plate 26a according to another embodiment will be described with reference to Figures 7(a) to (c). The end plate 6a according to the above embodiment and the end plate 26a according to this embodiment differ in that the surface on which the oxidant gas discharge hole outer opening 13a of the oxidant gas discharge hole 13 is formed is not the outer end surface 17 but the left side surface 18c, and there are no other differences in configuration. In the description of the end plate 26a of this embodiment, configurations common to the end plate 6a of the above embodiment are denoted by the same reference numerals. Further, detailed description of the configurations common to the end plate 6a will be omitted.

[0039] The end plate 26a according to this embodiment is a rectangular parallelepiped plate having an inner end face 16 as a first face connected to one end face of the fuel cell stack 3, an outer end face 17 as an opposite face facing the inner end face 16, and an outer peripheral face 18 disposed between the inner end face 16 and the outer end face 17. The outer peripheral face 18 is composed of an upper side face 18a on the upper side, a lower side face 18b on the lower side, a left side face 18c disposed on the left side when the fuel cell 1 is viewed from the front, and a right side face 18d disposed on the right side when the fuel cell 1 is viewed from the front. In the oxidant gas discharge hole 13, an oxidant gas discharge hole outer opening 13a, which is an opening to which an external pipe (not shown) is connected, is formed on the left side face 18c of the end plate 26a. The left side face 18c is the second face in the present invention.

[0040] The oxidant gas discharge hole outer opening 13a is disposed lower in the up-down direction than the oxidant gas discharge hole inner opening 13b. Furthermore, a lower surface 13c located on the lower side in the up-down direction, which is the direction of gravity, of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a. Here, the lower surface 13c refers to a surface of the inner circumferential surface forming the oxidant gas discharge hole 13 that comes into contact with the water that is generated in the fuel cell stack 3 and flows from the oxidant gas discharge passage 8 into the oxidant gas discharge hole 13.

[0041] 7(a) to 7(c), the oxidant gas discharge hole inner opening 13b is a vertically long rectangle, and the oxidant gas discharge hole outer opening 13a is a circle, but the oxidant gas discharge hole 13 is gradually deformed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. Here, gradual deformation means that the shape is gradually changed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. The oxidant gas discharge hole inner opening 13b is an inner connection port in the present invention, and the oxidant gas discharge hole outer opening 13a is an outer connection port in the present invention.

[0042] When water vapor contained in the oxidant gas condenses in the fuel cell stack 3 to generate water, the generated water reaches the oxidant gas discharge hole 13 via the oxidant gas discharge passage 8, but in the end plate 6a according to this embodiment, the lower surface 13c of the inner circumferential surface forming the oxidant gas discharge hole 13 is inclined downward from the oxidant gas discharge hole inner opening 13b toward the oxidant gas discharge hole outer opening 13a. Therefore, the generated water flows by gravity to the oxidant gas discharge hole outer opening 13a side and is drained outside the fuel cell 1. This makes it possible to prevent a decrease in power generation performance due to accumulation of generated water.

[0043] Furthermore, in the end plate 6a according to this embodiment, the oxidant gas discharge hole 13 is gradually changed so that no step is formed between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. This reduces the energy loss of the generated water flowing through the oxidant gas discharge hole 13, making it easier to discharge the generated water and preventing a decrease in power generation performance.

[0044] In addition, since the oxidant gas discharge hole outer opening 13a is formed on the left side surface 18c of the end plate 26a, for example, if an external piping (not shown) connected to the oxidant gas discharge hole outer opening 13a cannot be placed on the outer end surface 17 side of the end plate 26a for layout reasons, it is possible to connect the piping to the oxidant gas discharge hole outer opening 13a.

[0045] In the present embodiment, the case has been described in which the oxidant gas discharge hole outer opening 13a is formed on the left side surface 18c of the end plate 26a, but the oxidant gas discharge hole outer opening 13a may be formed on any of the other side surfaces 18a, 18b, 18d of the outer peripheral surface 18. In addition, any or all of the other outer connection ports, i.e., the fuel gas supply hole outer opening 10a, the coolant discharge hole outer opening 15a, the oxidant gas supply hole outer opening 12a, the coolant supply hole outer opening 14a, and the fuel gas discharge hole outer opening 11a, may be formed on the left side surface 18c of the end plate 26a or on the other side surfaces 18a, 18b, 18d of the outer peripheral surface 18.

[0046] In the above embodiment, the oxidant gas discharge hole inner opening 13b is a vertically long rectangular shape, and the oxidant gas discharge hole outer opening 13a is a circular shape. However, the shapes of the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a are not limited to this. It is sufficient that the oxidant gas discharge hole 13 is gradually changed so that no step is generated between the oxidant gas discharge hole inner opening 13b and the oxidant gas discharge hole outer opening 13a. The same applies to the other through holes.

[0047] Although the embodiment and its modified examples of the present invention have been described above, the present invention is not limited to the above-described embodiment and modified examples, and further modifications and changes are possible based on the technical concept of the present invention. [Explanation of symbols]

[0048] 1...fuel cell 2...Fuel cell stack 2a…Fuel cell 3...Fuel cell stack 4...Current collector plate 5…Insulating plate 6a…End plate 6b…End plate 7...Fuel gas supply passage 7a…Entrance side opening 8...Oxidant gas exhaust passage 8a…Exit side opening 9…Cooling medium discharge passage 9a…Exit side opening 10...Fuel gas supply hole 10a...Outer opening of fuel gas supply hole 10b...Fuel gas supply hole inner opening 11...Fuel gas exhaust hole 11a…Fuel gas exhaust hole outer opening 11b...Fuel gas exhaust hole inner opening 11c…lower surface 12...Oxidant gas supply hole 12a...Oxidant gas supply hole outer opening 12b...Oxidant gas supply hole inner opening 13...Oxidant gas exhaust hole 13a...Oxidant gas exhaust hole outer opening 13b...Inner opening of oxidizer gas exhaust hole 14…Cooling medium supply hole 14a…Cooling medium supply hole outer opening 14b…Cooling medium supply hole inner opening 15…Cooling medium discharge hole 15a…Cooling medium discharge hole outer opening 15b…Cooling medium discharge hole inner opening 15c…lower surface 16...Inner end surface 17…Outer end face 18…Outer surface 18a…Top side 18b…Bottom side 18c…Left side 18d…Right side 26a…End plate

Claims

1. In a fuel cell including a fuel cell stack including a plurality of stacked fuel cells, there is provided an end plate for a fuel cell, which is disposed at one end of the fuel cell stack in a stacking direction, The fuel cell end plate comprises: an inner connection port formed on a first surface of the end plate for the fuel cell, the inner connection port being connected to an outlet opening of a fluid passage passing through the fuel cell stack in a stacking direction; an outer connection port formed on a second surface of the end plate for the fuel cell, the second surface being different from the first surface, the outer connection port being connected to an external pipe; a through hole communicating between the inner connection port and the outer connection port, 13. An end plate for a fuel cell, wherein a lower surface of an inner circumferential surface forming the through hole is inclined downward from the inner connection port toward the outer connection port.

2. The shape of the inner connection port and the shape of the outer connection port are different, 2. The end plate for a fuel cell according to claim 1, wherein the through hole is gradually formed so that no step is created between the inner connection port and the outer connection port.

3. 3. The end plate for a fuel cell according to claim 2, wherein the inner connection port has a rectangular shape, and the outer connection port has a circular shape.

4. The end plate for the fuel cell has the first surface and an opposite surface facing the first surface, 3. The end plate for a fuel cell according to claim 2, wherein the second surface is the opposite surface.

5. the end plate for the fuel cell has the first surface, an opposite surface facing the first surface, and an outer circumferential surface between the first surface and the opposite surface, 3. The end plate for a fuel cell according to claim 2, wherein the second surface is the outer circumferential surface.

6. 4. The end plate for a fuel cell according to claim 3, wherein the fluid passage is an oxidant gas discharge passage through which an oxidant gas is discharged.

7. 1. A fuel cell comprising: An end plate for a fuel cell according to any one of claims 1 to 6; the fuel cell stack; A fuel cell comprising:

Images