JP3981476B2 - Fuel cell stack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell stack in which a plurality of unit fuel cells and separators each having a solid polymer electrolyte membrane sandwiched between an anode electrode and a cathode electrode are alternately stacked.
[0002]
[Prior art]
In the polymer electrolyte fuel cell, a unit fuel cell in which an anode electrode and a cathode electrode are arranged on both sides of an electrolyte composed of a polymer ion exchange membrane (cation exchange membrane) is usually sandwiched between separators. A fuel cell stack is formed by stacking a plurality of them.
[0003]
In this type of fuel cell stack, a fuel gas, for example, hydrogen gas, supplied to the anode side electrode is hydrogen ionized on the catalyst electrode and moves to the cathode side electrode side through an appropriately humidified electrolyte. Electrons generated in the meantime are taken out to an external circuit and used as direct current electric energy. Since the oxidant gas, for example, oxygen gas or air is supplied to the cathode side electrode, water reacts with the hydrogen ions, the electrons and oxygen to generate water.
[0004]
In this case, the electrolyte composed of the polymer ion exchange membrane needs to be sufficiently humidified in order to maintain ion permeability. For this reason, in general, the oxidant gas and the fuel gas are humidified using a gas humidifier provided outside the fuel cell, and these are sent to the fuel cell stack as water vapor to humidify the electrolyte. It is configured as follows.
[0005]
[Problems to be solved by the invention]
By the way, since a solid polymer fuel cell has a relatively low operating temperature (up to 100 ° C.), before the moisture supplied to the oxidant gas or fuel gas for humidification is introduced into the fuel cell stack, piping is performed. There is a risk of condensation inside. On the other hand, moisture that has not been absorbed by the electrolyte after being introduced into the fuel cell stack or moisture generated by the reaction is cooled in the pipe after being discharged from the gas flow path in the fuel cell stack or the fuel cell stack, It tends to exist in the water state.
[0006]
However, as described above, if water is present in the piping near the fuel cell stack or in the gas flow path in the fuel cell stack, it is difficult to sufficiently supply the oxidant gas and fuel gas to each unit fuel cell. Become. Thereby, the problem that the diffusibility to the catalyst electrode layer of the fuel gas and oxidant gas which are reaction gas falls and the cell performance deteriorates remarkably is pointed out.
[0007]
The present invention solves this type of problem, and it is an object of the present invention to provide a fuel cell stack that can reliably prevent unnecessary water from being introduced into the fuel cell stack and can be simplified in configuration. And
[0008]
[Means for Solving the Problems]
In the fuel cell stack according to the present invention, the manifold member incorporated in the fuel cell stack includes the first and second inlet pipes that form the inlet side of the fuel gas flow path and the oxidant gas flow path, and the fuel gas flow A first and second outlet pipes that form a passage and an outlet side of the oxidant gas flow path, an inlet space in which a refrigerant flow path surrounds the first and second outlet pipes, and the first And an outlet space surrounding the second inlet tube . As a result, the manifold member adopts a double pipe structure as a whole, and the gas inlet / outlet temperatures of the fuel gas channel and the oxidant gas channel can be adjusted to substantially the same temperature as the fuel cell stack, The whole manifold member can be easily reduced in size and simplified. Moreover, the cooling medium is first introduced into the fuel cell stack after warming the manifold member through the manifold member. Further, the cooling medium absorbs heat when passing through the inside of the fuel cell stack and rises in temperature, and is then introduced from the fuel cell stack into the manifold member to heat the manifold member.
[0009]
Thereby, a temperature difference does not occur between the manifold member and the fuel cell stack, and water vapor contained in the fuel gas or the oxidant gas does not condense in the manifold. Therefore, it is possible to reliably prevent the water vapor from condensing near the gas inlet and the gas outlet of the fuel cell stack and introducing unnecessary water into the gas flow path in the fuel cell stack. It becomes possible to supply each fuel cell stack satisfactorily and smoothly.
[0010]
Further, in the present invention, in a fuel cell stack in which a plurality of fuel cell stacks are integrally connected by a manifold member to obtain a large output, the manifold member is heated via a cooling medium. The temperature difference with each fuel cell stack is reduced. Thereby, it is possible to reliably prevent water vapor from condensing in the vicinity of each fuel cell stack, and to prevent water from entering the gas flow path in each fuel cell stack.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic perspective view of a fuel cell stack 10 according to the first embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of the fuel cell stack 10.
[0013]
The fuel cell stack 10 includes a unit fuel cell 12 and first and second separators 14 and 16 that sandwich the unit fuel cell 12, and a plurality of these are stacked in the direction of arrow A as necessary. In addition, a manifold member 18 is connected to one end side in the stacking direction. The unit fuel cell 12 includes a solid polymer electrolyte membrane 20, and an anode side electrode 22 and a cathode side electrode 24 that are disposed with the electrolyte membrane 20 interposed therebetween.
[0014]
First and second gaskets 26 and 28 are provided on both sides of the unit fuel cell 12, and the first gasket 26 has a large opening 30 for accommodating the anode side electrode 22, while the second The gasket 28 has a large opening 32 for accommodating the cathode side electrode 24 (see FIG. 2). The unit fuel cell 12 and the first and second gaskets 26 and 28 are sandwiched between the first and second separators 14 and 16, and a plurality of sets are stacked in the horizontal direction (direction of arrow A).
[0015]
In the fuel cell stack 10, a fuel gas supply channel 34, an oxidant gas supply channel 36 and a cooling water discharge channel 38 are integrally formed on the upper side, and a fuel gas discharge channel is formed on the lower side. The passage 40, the oxidizing gas discharge passage 42, and the cooling water supply passage 44 are integrally formed.
[0016]
As shown in FIG. 2, a first flow that extends in the up-down direction through the fuel gas supply flow path 34 and the fuel gas discharge flow path 40 communicates with the surface portion of the first separator 14 that faces the anode side electrode 22. A path 46 is formed. A second channel 48 extending in the vertical direction is formed on the surface of the second separator 16 facing the cathode side electrode 24 so as to communicate with the oxidant gas supply channel 36 and the oxidant gas discharge channel 42. The A third flow path 50 that extends in the vertical direction is formed on the other surface portion of each of the first and second separators 14 and 16 so as to communicate with the cooling water supply flow path 44 and the cooling water discharge flow path 38. .
[0017]
As shown in FIGS. 1 and 2, the manifold member 18 has a substantially rectangular shape. The manifold member 18 has a fuel gas passage 52 for supplying hydrogen gas (fuel gas) to the anode side electrode 22, and a cathode side electrode 24. An oxidant gas channel 54 that supplies air (or oxygen gas) that is an oxidant gas, and a refrigerant channel 56 that supplies a cooling medium, for example, cooling water, are provided. The fuel gas passage 52 and the oxidant gas passage 54 are set on the inlet side.
[0018]
Inside the manifold member 18, an inlet space 58 constituting the refrigerant flow path 56 is formed on the lower side, and an outlet space 60 constituting the refrigerant flow path 56 is formed on the upper side. A cooling water inlet 62 communicating with the inlet space 58 and a cooling water outlet 64 communicating with the outlet space 60 are formed on the narrow side portion 18 a of the manifold member 18, and the wide surface portion of the manifold member 18 is formed. 18 b is formed with an introduction hole 66 that communicates the inlet space 58 and the cooling water supply channel 44, and a lead-out hole 68 that communicates the outlet space 60 and the cooling water discharge channel 38.
[0019]
In the outlet space 60, a first inlet pipe 70 constituting the fuel gas flow path 52 is disposed, and one end 70a of the first inlet pipe 70 is led out from the side part 18a of the manifold member 18 to the outside. In addition, the other end portion 70 b of the first inlet pipe body 70 is connected to the fuel gas supply flow path 34 in the fuel cell stack 10 from the surface portion 18 b of the manifold member 18. A second inlet pipe 72 constituting the oxidant gas flow path 54 is disposed in the outlet space 60, and one end 72 a of the second inlet pipe 72 is led out from the side part 18 a of the manifold member 18 to the outside. At the same time, the other end 72 b of the second inlet pipe 72 is connected to the oxidant gas supply channel 36 from the surface 18 b of the manifold member 18.
[0020]
In the inlet space 58, a first outlet pipe body 74 constituting the fuel gas flow path 52 and a second outlet pipe body 76 constituting the oxidant gas flow path 54 are arranged. The end portions 74a and 76a of the first and second outlet pipe bodies 74 and 76 are led out from the surface portion 18b of the manifold member 18, while the end portions 74b and 76b are respectively fueled from the surface portion 18b of the manifold member 18. The gas discharge channel 40 and the oxidant gas discharge channel 42 are connected. As shown in FIG. 3, a cooling water tank 78 and a pump 80 are arranged along the refrigerant flow path 56, and the cooling water circulates in the cooling water tank 78 and the fuel cell stack 10.
[0021]
The operation of the fuel cell stack 10 according to the first embodiment configured as described above will be described below.
[0022]
As shown in FIG. 3, the cooling water in the cooling water tank 78 is introduced into the inlet space 58 from the cooling water inlet 62 of the manifold member 18 through the refrigerant flow path 56 under the action of the pump 80 (FIG. 1). reference). The cooling water is supplied to the cooling water supply passage 44 in the fuel cell stack 10 from the introduction hole portion 66 communicating with the inlet space 58, and flows through the third passage 50 of the first and second separators 14, 16 from below. By flowing upward, each unit fuel cell 12 is cooled (see FIG. 2). Further, the cooling water is led out from the cooling water discharge channel 38 to the outlet space 60, and then returned from the cooling water outlet 64 to the cooling water tank 78 through the refrigerant channel 56.
[0023]
The hydrogen gas introduced into the fuel gas passage 52 is supplied to the fuel gas supply passage 34 from the end portion 70 b through the first inlet pipe body 70. The hydrogen gas is supplied to the anode side electrode 22 of the unit fuel cell 12 while moving downward along the first flow path 46 of the first separator 14. On the other hand, the air introduced into the oxidant gas flow channel 54 is similarly sent from the end 72 b of the second inlet pipe 72 to the oxidant gas supply flow channel 36. The air is supplied to the cathode side electrode 24 constituting the unit fuel cell 12 while moving downward along the second flow path 48 of the second separator 16.
[0024]
Thus, the hydrogen gas supplied to the anode side electrode 22 is hydrogen ionized and moves to the cathode side electrode 24 side through the electrolyte membrane 20, and power is generated in each unit fuel cell 12. The unused hydrogen gas is sent from the fuel gas discharge channel 40 to the first outlet tube 74, and the unused air is led out from the oxidant gas discharge channel 42 to the second outlet tube 76. The
[0025]
In this case, the temperature of the fuel cell stack 10 during operation is 70 ° C. to 90 ° C., and the hydrogen gas and air supplied to the fuel cell stack 10 are 70 ° C. to 70 ° C. on the inlet side and outlet side of the manifold member 18. It is adjusted within a temperature range of 90 ° C. However, the temperature of the manifold member 18 tends to be lower than the operating temperature of each unit fuel cell 12, and the first and second inlet pipes 70, 72 arranged in the manifold member 18 and the first and second In the second outlet pipes 74 and 76, hydrogen gas and water vapor contained in the air may condense and water may be generated.
[0026]
Therefore, in the first embodiment, an inlet space 58 is provided in the manifold member 18 so as to surround the first and second outlet pipe bodies 74 and 76, and the first and second inlet pipe bodies 70 and 72 are surrounded. Thus, the outlet space 60 is formed. Then, the cooling water circulating through the cooling water tank 78 and the inside of the fuel cell stack 10 is first introduced into the inlet space 58 to warm the inside of the manifold member 18, and then, by cooling each unit fuel cell 12. The temperature is raised and introduced into the outlet space 60 to warm the manifold member 18. The cooling water is further returned from the cooling water outlet 64 to the cooling water tank 78 via the refrigerant channel 56 and then sent to the manifold member 18 side. Note that when the fuel cell stack 10 is started up, the temperature of the cooling water is lower than the temperature of hydrogen gas or air, so the cooling water is warmed by a heater or the like and supplied to the inlet space 58.
[0027]
As described above, in the first embodiment, the temperature difference between the manifold member 18 and each unit fuel cell 12 can be reduced by heating the manifold member 18 with the cooling water. Therefore, hydrogen gas or water vapor contained in the air condenses in the first and second inlet pipes 70 and 72 and the first and second outlet pipes 74 and 76 arranged in the manifold member 18. There is nothing to do.
[0028]
In particular, an outlet space 60 is provided so as to surround the first and second inlet pipes 70 and 72, and the first and second inlet pipes 70 and 72 are reliably kept warm by the heated cooling water. Can be warmed. Accordingly, it is possible to prevent the generation of water in the first and second inlet pipes 70 and 72 and effectively prevent the water from being introduced into the fuel cell stack 10 on the gas flow. Become.
[0029]
As a result, it is possible to reliably prevent water from staying in the manifold member 18 and the fuel cell stack 10 and to distribute hydrogen gas and air uniformly and smoothly to each unit fuel cell 12. It is done. Accordingly, the fuel cell stack 10 can be stably operated for a long time.
[0030]
FIG. 4 is a schematic perspective explanatory view of the fuel cell stack 100 according to the second embodiment of the present invention. The same components as those of the fuel cell stack 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.
[0031]
The fuel cell stack 100 is configured by integrally connecting a plurality of fuel cell stacks 102 a to 102 d with a manifold member 104. As shown in FIGS. 4 and 5, in the outlet space 60 formed in the manifold member 104, the first inlet pipe body 106 that constitutes the fuel gas passage 52 and the second that constitutes the oxidant gas passage 54. An inlet tube 108 is disposed.
[0032]
The first and second inlet pipes 106 and 108 have end portions 106a and 106b and end portions 108a corresponding to the fuel gas supply channels 34 and the oxidant gas supply channels 36 of the fuel cell stacks 102a and 102b, respectively. , 108b are formed, and end portions 106c, 106d and end portions 108c, 108d are provided corresponding to the fuel gas supply channel 34 and the oxidant gas supply channel 36 of the fuel cell stacks 102c, 102d.
[0033]
In the inlet space 58 of the manifold member 104, a first outlet pipe body 110 constituting the fuel gas flow path 52 and a second outlet pipe body 112 constituting the oxidant gas flow path 54 are arranged. The first and second outlet pipes 110 and 112 have end portions 110a to 110d and end portions 112a to 112d communicating with the fuel gas discharge passage 40 and the oxidant gas discharge passage 42 of each fuel cell stack 102a to 102d. Is formed.
[0034]
The both surfaces 104a and 104b of the manifold member 104 are provided with introduction hole portions 114a to 114d communicating with the cooling water supply passage 44 and the inlet space 58 of the fuel cell stacks 102a to 102d, and the fuel cell stacks 102a to 102d. Lead-out holes 116 a to 116 d communicating with the cooling water discharge channel 38 and the outlet space 60 are formed.
[0035]
In the second embodiment configured as described above, the fuel cell stack 100 is configured by integrally connecting the plurality of fuel cell stacks 102a to 102d to the manifold member 104, and a large output can be obtained. In addition, the fuel gas passage 52 and the oxidant gas passage 54 can be integrated into a single manifold member 104, the gas passage length can be shortened at once, and the manifold member 104 can be downsized. There is an effect that it can be easily achieved.
[0036]
Further, in the second embodiment, the temperature difference between the manifold member 104 and each of the fuel cell stacks 102a to 102d is effectively reduced to prevent water vapor from condensing, so that water enters the fuel cell stacks 102a to 102d. Can be surely prevented.
[0037]
【The invention's effect】
In the fuel cell stack according to the present invention, since the manifold member is provided with the fuel gas flow path, the oxidant gas flow path, and the refrigerant flow path, the manifold member can be heated via the cooling medium, It is possible to reduce the temperature difference between the manifold member and the unit fuel battery cell and reliably prevent the condensation of water vapor. Furthermore, the outlet side of the refrigerant flow path is set to the inlet side of the fuel gas flow path and the oxidant gas flow path, and the temperature of the fuel gas and the oxidant gas is made uniform, and the gas flow is carried in the fuel cell stack. Thus, introduction of water can be avoided.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a fuel cell stack according to a first embodiment of the present invention.
FIG. 2 is an explanatory view of a longitudinal section of the fuel cell stack.
FIG. 3 is an explanatory diagram of a refrigerant flow path constituting the fuel cell stack.
FIG. 4 is a schematic perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention.
FIG. 5 is a longitudinal sectional view of a manifold member constituting the fuel cell stack.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10, 100, 102a-102d ... Fuel cell stack 12 ... Unit fuel cell 14, 16 ... Separator 18, 104 ... Manifold member 20 ... Electrolyte membrane 22 ... Anode side electrode 24 ... Cathode side electrode 34 ... Fuel gas supply flow path 36 ... Oxidant gas supply flow path 38 ... Cooling water discharge flow path 40 ... Fuel gas discharge flow path 42 ... Oxidant gas discharge flow path 44 ... Cooling water supply flow paths 46, 48, 50 ... Flow path 52 ... Fuel gas flow path 54 ... Oxidant gas channel 56 ... Refrigerant channel 58 ... Inlet space 60 ... Outlet space 62 ... Cooling water inlet 64 ... Cooling water outlet 66, 114a-114d ... Inlet hole 68, 116a-116d ... Outlet hole 70, 72, 106, 108 ... Inlet pipe body 74, 76, 110, 112 ... Outlet pipe body 78 ... Cooling water tank 80 ... Pump

Claims (2)

A fuel cell stack in which a solid polymer electrolyte membrane is sandwiched between an anode side electrode and a cathode side electrode and a plurality of unit fuel cells and separators are alternately stacked, and manifold members are connected.
The manifold member includes a first inlet pipe that forms an inlet side of a fuel gas flow path that supplies fuel gas to the anode side electrode;
A first outlet tube forming an outlet side of the fuel gas flow path;
A second inlet tube forming an inlet side of an oxidant gas flow path for supplying an oxidant gas to the cathode side electrode;
A second outlet tube forming an outlet side of the oxidant gas flow path;
An inlet space that forms an inlet side of a refrigerant flow path for supplying a cooling medium for cooling the unit fuel cell, and surrounds the first and second outlet pipes;
An outlet space forming an outlet side of the refrigerant flow path and surrounding the first and second inlet pipes;
A fuel cell stack, wherein the Ruco provided. A fuel in which a plurality of fuel cell stacks in which a plurality of unit fuel cells and separators each having a solid polymer electrolyte membrane sandwiched between an anode side electrode and a cathode side electrode are alternately stacked are integrally connected by a manifold member A battery stack,
The manifold member includes a first inlet tube that forms an inlet side of a fuel gas flow path that supplies fuel gas to the anode side electrode of each fuel cell stack;
A first outlet tube forming an outlet side of the fuel gas flow path;
A second inlet tube forming an inlet side of an oxidant gas flow path for supplying an oxidant gas to the cathode side electrode;
A second outlet tube forming an outlet side of the oxidant gas flow path;
An inlet space that forms an inlet side of a refrigerant flow path for supplying a cooling medium for cooling each fuel cell stack and surrounds the first and second outlet pipes;
An outlet space forming an outlet side of the refrigerant flow path and surrounding the first and second inlet pipes;
A fuel cell stack, wherein the Ruco provided.

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