JP6401684B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a power generation cell in which an electrolyte membrane / electrode structure in which electrodes are disposed on both surfaces of an electrolyte membrane is sandwiched between a cathode separator and an anode separator, and a laminate in which a plurality of the power generation cells are stacked. The present invention relates to a fuel cell stack provided.

  In general, a polymer electrolyte fuel cell employs a polymer electrolyte membrane made of a polymer ion exchange membrane. The fuel cell includes an electrolyte membrane / electrode structure (MEA) in which an anode electrode is disposed on one surface of a solid polymer electrolyte membrane and a cathode electrode is disposed on the other surface of the solid polymer electrolyte membrane. Yes. The anode electrode and the cathode electrode each have a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon).

  The electrolyte membrane / electrode structure constitutes a power generation cell (unit fuel cell) by being sandwiched between separators (bipolar plates). The power generation cells are used as, for example, an in-vehicle fuel cell stack by being stacked in a predetermined number.

  In the fuel cell stack, there is a power generation cell in which a temperature drop is likely to be caused by heat radiation to the outside as compared with other power generation cells. For example, a power generation cell (hereinafter also referred to as an end power generation cell) arranged at the end in the stacking direction has a large amount of heat released from, for example, a power extraction terminal plate (current collector plate) or an end plate. The temperature drop is remarkable.

  Thus, for example, a polymer electrolyte fuel cell stack disclosed in Patent Document 1 has been proposed. This polymer electrolyte fuel cell stack is characterized in that a heat insulating layer is interposed between a single cell located at at least one end in the stacking direction and a terminal plate disposed on the outside thereof. According to this, heat transfer from the single cell located at the end in the stacking direction to the terminal plate is hindered by the heat insulating layer, so that the amount of heat radiation from the terminal plate to the outside is reduced and the temperature of the single cell is lowered. Can be suppressed.

JP 2002-184449 A

  By the way, as described above, sufficient thermal insulation performance may not be obtained only by interposing a thermal insulation layer between the end unit cell and the terminal plate. Moreover, the structure becomes complicated, and there is a possibility that it cannot be economically manufactured.

  An object of the present invention is to solve this type of problem, and to provide a fuel cell stack capable of suppressing the degradation of the performance of an end power generation cell as much as possible with a simple and economical configuration. And

  The present invention relates to a fuel cell stack including a stacked body in which a plurality of power generation cells are stacked. In the power generation cell, an electrolyte membrane / electrode structure in which electrodes are disposed on both surfaces of the electrolyte membrane is sandwiched between a cathode separator and an anode separator. An oxidant gas is circulated along the electrode surface in the cathode separator, while a fuel gas is circulated along the electrode surface in the anode separator.

  In the fuel cell stack, the first end power generation cell disposed at one end in the stacking direction of the stack has a cathode separator at the outermost portion in the stacking direction, and the second end disposed at the other end in the stacking direction of the stack. The power generation cell has an anode separator on the outermost side in the stacking direction. The flow rate of the oxidant gas flowing through the first end power generation cell is larger than the flow rate of the oxidant gas flowing through the second end power generation cell.

  Further, in this fuel cell stack, a first cooling medium passage for circulating a cooling medium is provided outside the stacking direction of the first end power generation cells, and outside the stacking direction of the second end power generation cells, It is preferable that a second cooling medium passage for circulating the cooling medium is provided. In that case, it is preferable that the flow rate of the cooling medium flowing through the first cooling medium passage is larger than the flow rate of the cooling medium flowing through the second cooling medium passage.

  According to the present invention, the first end power generation cell has a cathode separator on the outermost side in the stacking direction, while the second end power generation cell has an anode separator on the outermost side in the stacking direction. The flow rate of the oxidant gas flowing through the first end power generation cell is larger than the flow rate of the oxidant gas flowing through the second end power generation cell.

  In particular, due to the end structure or the like, the first end power generation cell that circulates the oxidant gas to the outermost part in the stacking direction is more radiated than the second end power generation cell that circulates the fuel gas to the outermost part in the stacking direction. There is a risk of flooding due to a large temperature drop. On the other hand, during high load operation of the fuel cell stack, the first end power generation cell that distributes the oxidant gas to the outermost part in the stacking direction due to a large current causes the second end power generation to distribute the fuel gas to the outermost part in the stacking direction. The amount of heat generation tends to be larger than that of the cell. For this reason, an excessive temperature rise may be caused in the first end power generation cell.

  Therefore, by causing a larger amount of oxidant gas to flow through the first end power generation cell than in the second end power generation cell, the humidity of the first end power generation cell is optimized and the occurrence of flooding is suppressed. The temperature rise of the first end power generation cell can be suppressed. Thereby, it becomes possible to suppress the performance degradation of the first end power generation cell as much as possible with a simple and economical configuration.

1 is an exploded schematic perspective view of a fuel cell stack according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. It is a disassembled perspective explanatory drawing of the electric power generation cell which comprises the said fuel cell stack.

  As shown in FIG. 1, a fuel cell stack 10 according to an embodiment of the present invention includes a stacked body 14 in which a plurality of power generation cells 12 are stacked in a horizontal direction (arrow A direction) or a vertical direction (arrow C direction). Prepare. The fuel cell stack 10 is mounted on, for example, a fuel cell electric vehicle (not shown) as an in-vehicle fuel cell stack.

  As shown in FIGS. 1 and 2, a first end power generation cell 12end. (C) is disposed at one end of the stack 14 in the stacking direction (arrow A direction), and the stack 14 is stacked in the stacking direction. A second end power generation cell 12end. (A) is disposed at the other end. As will be described later, the first end power generation cell 12end. (C) has a cathode separator 34 on the outermost side in the stacking direction, while the second end power generation cell 12end. (A) has an anode separator on the outermost side in the stacking direction. 30.

  In the first end power generation cell 12end. (C), a terminal plate 16a, an insulating member 18a, a flow path plate 20a, and an end plate 22a are sequentially arranged outward in the stacking direction. In the second end power generation cell 12end. (A), a terminal plate 16b, an insulating member 18b, a flow path plate 20b, a stacking adjustment plate 24, and an end plate 22b are sequentially arranged outward in the stacking direction. The

  The fuel cell stack 10 is integrally held by, for example, a box-shaped casing (not shown) including end plates 22a and 22b configured in a rectangular shape as end plates. The fuel cell stack 10 may be integrally clamped and held by a plurality of tie rods (not shown) extending in the direction of arrow A, for example.

  As shown in FIGS. 2 and 3, the power generation cell 12 includes an anode separator 30, an electrolyte membrane / electrode structure (electrolyte / electrode structure) (MEA) 32, and a cathode separator 34. The anode separator 30 and the cathode separator 34 are made of, for example, a vertically long metal plate such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate.

  The anode separator 30 and the cathode separator 34 may be carbon separators instead of metal separators. The power generation cell 12 may be configured by stacking a first separator, a first MEA, a second separator, a second MEA, and a third separator. Furthermore, the power generation cell 12 may have three or more MEAs and five or more separators.

  As shown in FIG. 3, one end edge of the power generation cell 12 in the long side direction (arrow B direction) (horizontal direction) communicates with each other in the direction of arrow A, which is the stacking direction, and the oxidant gas inlet communication hole 36a. And a fuel gas inlet communication hole 38a. The oxidant gas inlet communication hole 36a supplies an oxidant gas, for example, an oxygen-containing gas. The fuel gas inlet communication hole 38a supplies a fuel gas, for example, a hydrogen-containing gas.

  The other end edge in the long side direction (arrow B direction) of the power generation cell 12 communicates with each other in the arrow A direction, and the fuel gas outlet communication hole 38b for discharging the fuel gas and the oxidant gas for discharging the oxidant gas. An outlet communication hole 36b is provided. The oxidant gas inlet communication hole 36a, the oxidant gas outlet communication hole 36b, the fuel gas inlet communication hole 38a, and the fuel gas outlet communication hole 38b are arranged so that the oxidant gas and the fuel gas are opposed to each other. May be.

  A pair of both ends of the power generation cell 12 in the short side direction (arrow C direction) (vertical direction) (on the oxidant gas inlet communication hole 36a side) communicate with each other in the arrow A direction and supply a cooling medium. The cooling medium inlet communication holes 40a1 and 40a2 are provided. The cooling medium inlet communication holes 40a1 and 40a2 are divided and formed independently of each other by providing a rib portion 41a at an intermediate portion in the longitudinal direction of a rectangular opening elongated in the horizontal direction.

  The other of the power generation cells 12 in the short side direction (oxidant gas outlet communication hole 36b side) is provided with a pair of cooling medium outlet communication holes 40b1 and 40b2 that communicate with each other in the direction of arrow A and discharge the cooling medium. . The cooling medium outlet communication holes 40b1 and 40b2 are divided and formed independently of each other by providing a rib portion 41b at an intermediate portion in the longitudinal direction of a rectangular opening that is long in the horizontal direction.

  The rib 41a is removed to make the cooling medium inlet communication holes 40a1, 40a2 a single cooling medium inlet communication hole, while the rib 41b is removed to make the cooling medium outlet communication holes 40b1, 40b2 a single cooling. It may be a medium outlet communication hole. Further, the fuel gas inlet communication hole 38a and the fuel gas outlet communication hole 38b may be configured to be interchanged with each other.

  A fuel gas flow path 42 that connects the fuel gas inlet communication hole 38 a and the fuel gas outlet communication hole 38 b is formed on the surface 30 a of the anode separator 30 facing the electrolyte membrane / electrode structure 32. The fuel gas channel 42 has a plurality of wavy channel grooves (or straight channel grooves).

  The fuel gas inlet communication hole 38a and the fuel gas flow path 42 communicate with each other via a plurality of inlet connection flow paths 44a, while the fuel gas outlet communication hole 38b and the fuel gas flow path 42 have a plurality of outlet connection flows. It communicates via the path 44b. The inlet connection channel 44a and the outlet connection channel 44b are covered with a lid body 46a and a lid body 46b.

  A part of the cooling medium flow path 48 that connects the pair of cooling medium inlet communication holes 40a1 and 40a2 and the pair of cooling medium outlet communication holes 40b1 and 40b2 is formed on the surface 30b of the anode separator 30, respectively.

  An oxidant gas flow path 50 that connects the oxidant gas inlet communication hole 36a and the oxidant gas outlet communication hole 36b is formed on the surface 34a of the cathode separator 34 facing the electrolyte membrane / electrode structure 32. The oxidant gas channel 50 has a plurality of wavy channel grooves (or straight channel grooves). A part of the cooling medium flow path 48 is formed on the surface 34 b of the cathode separator 34.

  A first seal member 52 is integrally formed on the surfaces 30 a and 30 b of the anode separator 30 around the outer peripheral edge of the anode separator 30. A second seal member 54 is integrally formed on the surfaces 34 a and 34 b of the cathode separator 34 around the outer peripheral edge of the cathode separator 34.

  For the first seal member 52 and the second seal member 54, for example, EPDM, NBR, fluoro rubber, silicone rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene or acrylic rubber or the like, cushion material Alternatively, an elastic seal member such as a packing material is used.

  As shown in FIGS. 2 and 3, the electrolyte membrane / electrode structure 32 includes a solid polymer electrolyte membrane 60 in which a perfluorosulfonic acid thin film is impregnated with water, for example. The solid polymer electrolyte membrane 60 is sandwiched between an anode electrode 62 and a cathode electrode 64. The anode electrode 62 constitutes a step MEA having a planar dimension smaller than that of the cathode electrode 64. Conversely, the anode electrode 62 may have a planar dimension larger than that of the cathode electrode 64. Further, the anode electrode 62 and the cathode electrode 64 may be set to have the same planar dimension.

  The anode electrode 62 and the cathode electrode 64 are formed by uniformly applying a gas diffusion layer (not shown) made of carbon paper or the like and porous carbon particles carrying a platinum alloy on the surface thereof to the surface of the gas diffusion layer. And an electrode catalyst layer (not shown) to be formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 60.

  As shown in FIG. 1, power extraction terminals 66 a and 66 b extending outward in the stacking direction are provided at positions separated from the in-plane center of the terminal plates 16 a and 16 b (may be the in-plane center). The power extraction terminals 66a and 66b are preferably set at positions closer to the cooling medium outlet communication holes 40b1 and 40b2 than the cooling medium inlet communication holes 40a1 and 40a2 of the cooling medium flow path 48.

  The insulating members 18a and 18b are made of an insulating material such as polycarbonate (PC) or phenol resin. As shown in FIGS. 1 and 2, a rectangular recess 68a is provided at the center of the surface of the insulating member 18a facing the terminal plate 16a, and a hole 70a communicates with the recess 68a. The power extraction terminal 66a of the terminal plate 16a is exposed to the outside through the hole 70a of the insulating member 18a, the hole 72a of the flow path plate 20a, and the hole 74a of the end plate 22a.

  A rectangular recess 68b is provided at the center of the surface of the insulating member 18b facing the terminal plate 16b, and a hole 70b communicates with the recess 68b. The power extraction terminal 66b of the terminal plate 16b is inserted into the hole 77h of the space 77 disposed on the bottom surface of the recess 68b of the insulating member 18b. The power extraction terminal 66b is further exposed to the outside from the hole 70b of the insulating member 18b through the hole 72b of the flow path plate 20b, the hole 76 of the stacking adjustment plate 24, and the hole 74b of the end plate 22b.

  As shown in FIG. 1, the insulating members 18a and 18b, the flow path plates 20a and 20b, and the end plate 22b have a pair of cooling medium inlet communication holes 40a1 and 40a2 and a pair of cooling medium outlet communication holes 40b1 and 40b2, respectively. It is formed. The insulating member 18a, the flow path plate 20a and the end plate 22a are formed with an oxidant gas inlet communication hole 36a, an oxidant gas outlet communication hole 36b, a fuel gas inlet communication hole 38a and a fuel gas outlet communication hole 38b.

  A cooling medium passage through which the cooling medium flows is formed in the surface 20as of the flow path plate 20a facing the insulating member 18a along the plate surface direction of the end plate 22a.

  The cooling medium passage communicates with the cooling medium inlet communication hole 40a1 disposed below and the cooling medium outlet communication hole 40b1 disposed above and a plurality of (for example, seven) first cooling medium passages meandering. 78a. The cooling medium passage communicates with the cooling medium inlet communication hole 40a2 disposed below and the cooling medium outlet communication hole 40b2 disposed above, and a plurality of (for example, four) first cooling medium passages meandering. 80a.

  On the surface 20bs of the flow path plate 20b facing the insulating member 18b, a cooling medium passage is formed through which the cooling medium flows along the plate surface direction of the end plate 22b.

  The cooling medium passage communicates with the cooling medium inlet communication hole 40a1 disposed below and the cooling medium outlet communication hole 40b1 disposed above and a plurality of (for example, seven) second cooling medium passages meandering. 78b. The cooling medium passage communicates with the cooling medium inlet communication hole 40a2 disposed below and the cooling medium outlet communication hole 40b2 disposed above, and a plurality of (for example, four) second cooling medium passages meandering. 80b.

  As shown in FIG. 2, the coolant flow rate Q1 flowing through the first coolant passages 78a and 80a is set to be larger than the coolant flow rate Q2 flowing through the second coolant passages 78b and 80b (Q1> Q2). . For example, the passage sectional areas of the first cooling medium passages 78a and 80a are set larger than the passage sectional areas of the second cooling medium passages 78b and 80b. Further, the pressure loss of the first cooling medium passages 78a and 80a may be set smaller than the pressure loss of the second cooling medium passages 78b and 80b, and various configurations such as a flow path length and a buffer unit can be employed. .

  As shown in FIGS. 1 and 2, the conductive heat insulating member 82a and the terminal plate 16a are accommodated in the recess 68a of the insulating member 18a. In the conductive heat insulating member 82a, for example, one second heat insulating member 86a is sandwiched between two first heat insulating members 84a. The first heat insulating member 84a is formed of, for example, a carbon plate, while the second heat insulating member 86a is formed of, for example, a metal plate having a concavo-convex shape to form an air chamber therebetween.

  The conductive heat insulating member 82b, the terminal plate 16b, and the space 77 are accommodated in the recess 68b of the insulating member 18b. The conductive heat insulating member 82b includes, for example, one first heat insulating member 84b and one second heat insulating member 86b.

  The conductive heat insulating members 82a and 82b may be members that retain pores and have electrical conductivity. For example, the electrically conductive foam metal, honeycomb-shaped metal (honeycomb member), or porous carbon (for example, , Carbon paper).

  As shown in FIG. 2, the laminated body 14 has the first end power generation cell 12end. (C) disposed at the end on the terminal plate 16a side, and the second end power generation cell 12end on the end on the terminal plate 16b side. (A) is arranged. Between the first end power generation cell 12end. (C) and the second end power generation cell 12end. (A), a stacked body in which a plurality of power generation cells 12 are stacked is interposed.

  The flow rate Qc of the oxidant gas flowing through the oxidant gas flow path 50 of the first end power generation cell 12end. (C) flows through the oxidant gas flow path 50 of the second end power generation cell 12end. (A). More than the flow rate Qa of the oxidant gas (Qc> Qa). The flow rate Qm of the oxidant gas flowing through the oxidant gas flow path 50 of the power generation cell 12 is smaller than the flow rate Qc and larger than the flow rate Qa (Qc> Qm> Qa).

  For example, the cross-sectional area of the oxidant gas flow path 50 constituting the first end power generation cell 12end. (C) is the same as that of the oxidant gas flow path 50 constituting the second end power generation cell 12end. (A). It is set to be larger than the channel cross-sectional area.

  Further, the pressure loss of the oxidant gas flow path 50 constituting the first end power generation cell 12end. (C) is set to be greater than the pressure loss of the oxidant gas flow path 50 constituting the second end power generation cell 12end. (A). It can be set small. For example, the pressure loss of the communication path connecting the oxidant gas flow path 50, the oxidant gas inlet communication hole 36a, and the oxidant gas outlet communication hole 36b may be adjusted. In addition, various pressure loss adjustments such as adjustment of the pressure loss of the buffer unit can be employed.

  A casing 88 is attached to the end plate 22a. In the casing 88, for example, an ejector 90 and a pump 92 for circulating and supplying fuel gas are accommodated. A cooling medium manifold 94 for circulatingly supplying the cooling medium is attached to the end plate 22b.

  The operation of the fuel cell stack 10 configured as described above will be described below.

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 36a of the end plate 22a. Fuel gas such as hydrogen-containing gas is supplied to the fuel gas inlet communication hole 38a of the end plate 22a. On the other hand, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the pair of cooling medium inlet communication holes 40a1 and 40a2 of the end plate 22b.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 50 of the cathode separator 34 from the oxidant gas inlet communication hole 36a. The oxidant gas moves in the direction of arrow B and is supplied to the cathode electrode 64 of the electrolyte membrane / electrode structure 32.

  On the other hand, the fuel gas is introduced into the fuel gas channel 42 of the anode separator 30 from the fuel gas inlet communication hole 38a. The fuel gas moves in the direction of arrow B along the fuel gas flow path 42 and is supplied to the anode electrode 62 of the electrolyte membrane / electrode structure 32.

  Therefore, in the electrolyte membrane / electrode structure 32, the oxidizing gas supplied to the cathode electrode 64 and the fuel gas supplied to the anode electrode 62 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is called.

  Next, the oxidant gas consumed by being supplied to the cathode electrode 64 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 36b. Similarly, the fuel gas consumed by being supplied to the anode electrode 62 is discharged in the direction of arrow A along the fuel gas outlet communication hole 38b.

  As shown in FIG. 3, the cooling medium supplied to the cooling medium inlet communication holes 40 a 1 and 40 a 2 is introduced into the cooling medium flow path 48 between the anode separator 30 and the cathode separator 34 adjacent to each other. The cooling medium flows in the direction of arrow C so as to be close to each other. The cooling medium further flows in the arrow B direction (the separator long side direction) to cool the electrolyte membrane / electrode structure 32. Next, the cooling medium flows in the direction of arrow C so as to be separated from each other, and is discharged from the respective cooling medium outlet communication holes 40b1 and 40b2.

  By the way, as shown in FIG. 1, the flow path plate 20a is provided with the first cooling medium passages 78a and 80a, while the flow path plate 20b is provided with the second cooling medium paths 78b and 80b.

  Therefore, in the flow path plate 20a, the cooling medium is introduced into the first cooling medium passages 78a and 80a from the lower cooling medium inlet communication holes 40a1 and 40a2. The cooling medium flows upward while meandering along the first cooling medium passages 78a and 80a, and then discharged to the lower cooling medium outlet communication holes 40b1 and 40b2.

  In the flow path plate 20b, the cooling medium is introduced into the second cooling medium passages 78b and 80b from the lower cooling medium inlet communication holes 40a1 and 40a2. The cooling medium flows upward while meandering along the second cooling medium passages 78b and 80b, and then discharged to the upper cooling medium outlet communication holes 40b1 and 40b2. Thus, the cooling medium flows upward from below, so that the air in the cooling medium can be discharged smoothly.

  As described above, the operation of the fuel cell stack 10 is performed. At that time, at the time of high load operation, the first end power generation cell 12end. (C) that distributes the oxidant gas to the outermost part in the stacking direction due to a large current, the second end part that distributes the fuel gas to the outermost part in the stacking direction. The calorific value is likely to be larger than that of the power generation cell 12end. Therefore, there is a possibility that an excessive temperature rise is caused in the first end power generation cell 12end. (C). This is because the heat generation on the cathode electrode 64 side is larger than the heat generation on the anode electrode 62 side during power generation.

  Furthermore, in particular, due to the end structure and the like, the first end power generation cell 12end. (C) is more likely to dissipate heat than the second end power generation cell 12end. (A). As a result, the first end power generation cell 12end. (C) may be flooded due to a temperature drop and generated water.

  Specifically, a casing 88 in which an ejector 90 and a pump 92 are accommodated is attached to the end plate 22a in which the first end power generation cell 12end. (C) is disposed. Heat dissipation is getting bigger. On the other hand, the stacking adjustment plate 24 and the cooling medium manifold 94 are attached to the end plate 22b where the second end power generation cell 12end. (A) is disposed, and heat radiation is reduced.

  Therefore, in this embodiment, the flow rate Qc of the oxidant gas flowing through the oxidant gas flow path 50 of the first end power generation cell 12end. (C) is the oxidant of the second end power generation cell 12end. (A). The flow rate is set to be larger than the flow rate Qa of the oxidant gas flowing through the gas flow path 50 (Qc> Qa). For this reason, it is possible to optimize the humidity of the first end power generation cell 12end. (C) to prevent the occurrence of flooding and to suppress the temperature rise. Therefore, the effect that it becomes possible to suppress the performance degradation of the first end power generation cell 12end. (C) as much as possible with a simple and economical configuration is obtained.

  Furthermore, in the present embodiment, the coolant flow rate Q1 flowing through the first coolant passages 78a and 80a is set to be larger than the coolant flow rate Q2 flowing through the second coolant passages 78b and 80b (Q1> Q2). ). As a result, the flow rate of the cooling medium as the temperature control medium is increased, the heat retaining function by the flow path plate 20a is improved, and the heat radiation from the first end power generation cell 12end. (C) can be satisfactorily suppressed. . For this reason, flooding can be prevented, and power generation by the first end power generation cell 12end. (C) can be stably performed.

  The first end power generation cell 12end. (C) and the second end power generation cell 12end. (A) are not limited to one, and may be configured by stacking a plurality of each.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Power generation cell 12end. (C), 12end. (A) ... End power generation cell 14 ... Laminated body 16a, 16b ... Terminal plate 18a, 18b ... Insulation member 20a, 20b ... Flow path plate 22a, 22b ... End plate 30 ... Anode separator 32 ... Electrolyte membrane / electrode structure 34 ... Cathode separator 36a ... Oxidant gas inlet communication hole 36b ... Oxidant gas outlet communication hole 38a ... Fuel gas inlet communication hole 38b ... Fuel gas outlet communication hole 40a1, 40a2 ... Cooling medium inlet communication holes 40b1, 40b2 ... Cooling medium outlet communication holes 42 ... Fuel gas flow path 48 ... Cooling medium flow path 50 ... Oxidant gas flow path 52, 54 ... Seal member 60 ... Solid polymer electrolyte membrane 62 ... Anode electrode 64 ... Cathode electrode
78a, 78b, 80a, 80b ... Cooling medium passages 82a, 82b ... Heat insulation member 88 ... Casing 94 ... Cooling medium manifold

Claims (2)

While sandwiching an electrolyte membrane / electrode structure in which electrodes are disposed on both surfaces of the electrolyte membrane between a cathode separator and an anode separator, an oxidizing gas is circulated along the electrode surface in the cathode separator, The anode separator has a power generation cell in which fuel gas flows along the electrode surface, and a fuel cell stack including a stack in which a plurality of the power generation cells are stacked,
The first end power generation cell disposed at one end in the stacking direction of the stacked body has the cathode separator on the outermost side in the stacking direction,
The second end power generation cell disposed at the other end in the stacking direction of the stacked body has the anode separator on the outermost side in the stacking direction,
The fuel cell stack, wherein a flow rate of the oxidant gas flowing through the first end power generation cell is larger than a flow rate of the oxidant gas flowing through the second end power generation cell. The fuel cell stack according to claim 1, wherein a first cooling medium passage for circulating a cooling medium is provided outside the stacking direction of the first end power generation cells,
A second cooling medium passage for circulating the cooling medium is provided outside the stacking direction of the second end power generation cell, and
The fuel cell stack, wherein a flow rate of the coolant flowing through the first coolant passage is greater than a flow rate of the coolant flowing through the second coolant passage.

Images