JP2010272361A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a temperature of an entire fuel cell stack to a desired power generation starting temperature uniformly and rapidly with a simple structure. <P>SOLUTION: The fuel cell stack 10 includes a plurality of stacked fuel cells 12. A first terminal plate 14a, a first insulation plate 16a, and a first end plate 18a are stacked on one end of the fuel cell 12 in a stack direction. A second terminal plate 14b, a second insulation plate 16b, and a second end plate 18b are stacked on other end in the stack direction. The fuel cell stack 10 includes a resistance unit 44 arranged on a side 10a having cooling medium inlet communication holes 30a among sides of the plurality of stacked fuel cells 12. The resistance unit 44 includes a casing 46 arranged along the side 10a, and a discharge resistance 48 is housed in the casing 46. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked and reacted along the stacking direction. The present invention relates to a fuel cell stack provided with a reaction gas communication hole through which a gas flows and a cooling medium communication hole through which a cooling medium flows.

  A fuel cell supplies a fuel gas (mainly hydrogen-containing gas) and an oxidant gas (mainly oxygen-containing gas) to the anode-side electrode and the cathode-side electrode and causes them to react electrochemically. It is a system that obtains electrical energy.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) provided with an anode electrode and a cathode electrode on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. Has a cell. This power generation cell is normally used as a fuel cell stack by alternately laminating a predetermined number of electrolyte membrane / electrode structures and separators.

  In this type of fuel cell, it is desired to quickly raise the temperature of the fuel cell to a temperature suitable for power generation at startup. Therefore, for example, in the solid polymer electrolyte fuel cell (stack) disclosed in Patent Document 1, as shown in FIG. 5, a plurality of single cells 1 are stacked and both ends of the single cells 1 in the stacking direction. A heating element 3 is interposed between the current collector 2 and the current collector plate 2. An electric insulating plate 4 and a pressure plate 5 are stacked outside the current collecting plate 2.

  A current output from the stack is passed through the heating element 3 in the thickness direction, so that the heating element 3 functions as an electric heating element. Therefore, by setting the value of the Joule heat generated in the heating element 3 to a value commensurate with the amount of heat dissipated from the end of the stack unit cells 1 in the stack direction, the temperature in the stack direction of the unit cells 1 can be reduced. The distribution is supposed to be uniform.

JP-A-8-167424

  However, in Patent Document 1 described above, a dedicated heating element 3 is used to raise the temperature of the stack. For this reason, there is a problem that the entire stack becomes larger and the facility cost increases. In addition, there is a problem in that the temperature of the entire stack cannot be raised uniformly and quickly to a desired power generation start temperature, particularly at low temperature startup.

  The present invention solves this type of problem, and an object thereof is to provide a fuel cell stack that can raise the temperature of the entire fuel cell stack uniformly and quickly to a desired power generation start temperature with a simple configuration. And

  The present invention includes a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked and reacted along the stacking direction. The present invention relates to a fuel cell stack provided with a reaction gas communication hole through which a gas flows and a cooling medium communication hole through which a cooling medium flows.

  In this fuel cell stack, a discharge resistor is disposed on the side portion of the plurality of fuel cells to be stacked, on the side portion where the cooling medium communication hole is provided.

  Further, in this fuel cell stack, a discharge resistor is arranged in a meandering manner along the side portion of the side portion of the fuel cell where the cooling medium communication hole is provided on the inlet side. Is preferred.

  In the present invention, the discharge resistor is disposed on the side portion provided with the cooling medium communication hole. For this reason, especially at the time of low temperature startup, the discharge process (discharge process) of the fuel cell stack is performed only by energizing the discharge resistor, and the heat generated from the discharge resistor is transmitted to the cooling medium.

  This makes it possible to raise the temperature of the entire fuel cell stack uniformly and quickly to a desired power generation start temperature with a simple configuration. Therefore, the startability of the fuel cell stack can be improved, and deterioration of the fuel cell stack can be suppressed.

1 is a schematic perspective view of a fuel cell stack according to an embodiment of the present invention. 2 is a partially exploded perspective view of the fuel cell stack. FIG. 2 is an exploded perspective view of a fuel cell constituting the fuel cell stack. FIG. It is a schematic explanatory drawing of the fuel cell system incorporating the said fuel cell stack. 2 is an explanatory diagram of a fuel cell of Patent Document 1. FIG.

  As shown in FIGS. 1 and 2, in the fuel cell stack 10 according to the embodiment of the present invention, a plurality of fuel cells 12 are stacked in the direction of arrow A (horizontal direction or vertical direction). The first terminal plate 14a, the first insulating plate 16a and the first end plate 18a are stacked at one end in the stacking direction of the fuel cell 12, while the second terminal plate 14b and the second insulating plate are stacked at the other end in the stacking direction. 16b and the second end plate 18b are stacked. Terminal plates 19a and 19b are integrally provided on the first terminal plate 14a and the second terminal plate 14b.

  As shown in FIG. 3, in the fuel cell 12, the electrolyte membrane / electrode structure 20 is sandwiched between the first and second separators 22 and 24. Although the 1st and 2nd separators 22 and 24 are comprised by the carbon separator, you may comprise by metal separators, such as a steel plate, a stainless steel plate, an aluminum plate, or a plating treatment steel plate, for example. The first separator 22, the electrolyte membrane / electrode structure 20, and the second separator 24 are stacked with a seal member (not shown) interposed therebetween.

  One end edge (upper edge) of the fuel cell 12 in the direction of arrow C (vertical direction in FIG. 3) communicates with each other in the direction of arrow A, which is the stacking direction, and an oxidant gas, for example, an oxygen-containing gas. An oxidant gas inlet communication hole 26a for supplying and a fuel gas inlet communication hole 28a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow B direction (horizontal direction).

  The other end edge (lower end edge) of the fuel cell 12 in the direction of arrow C communicates with each other in the direction of arrow A to discharge the fuel gas outlet communication hole 28b for discharging the fuel gas and the oxidant gas. For this purpose, the oxidant gas outlet communication holes 26b are arranged in the arrow B direction.

  A plurality of, for example, four cooling medium inlet communication holes 30a for supplying a cooling medium, and four cooling medium outlet communication holes for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow B direction. 30b is provided.

  An oxidant gas flow path 32 communicating with the oxidant gas inlet communication hole 26a and the oxidant gas outlet communication hole 26b is provided on the surface 22a of the first separator 22 facing the electrolyte membrane / electrode structure 20.

  A fuel gas passage 34 communicating with the fuel gas inlet communication hole 28a and the fuel gas outlet communication hole 28b is provided on the surface 24a of the second separator 24 facing the electrolyte membrane / electrode structure 20.

  A cooling medium that connects the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 that constitute the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 40 and an anode side electrode 42 that sandwich the solid polymer electrolyte membrane 38. With.

  The cathode side electrode 40 and the anode side electrode 42 are formed by uniformly applying a gas diffusion layer 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. An electrode catalyst layer. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 38.

  As shown in FIGS. 1 and 2, the fuel cell stack 10 is formed in the side portion 10 a provided with the cooling medium inlet communication hole 30 a (cooling medium communication hole) among the side portions of the plurality of stacked fuel cells 12. A resistance unit 44 is provided. The resistance unit 44 includes a casing 46 disposed along the side portion 10 a, and a discharge resistor 48 is accommodated in the casing 46.

  The discharging resistor 48 meanders along the side portion 10a, that is, alternately turns back at both ends in the direction of the arrow C and extends in the surface direction of the side portion 10a. Both end portions 48a and 48b of the discharging resistor 48 are electrically connected to the first terminal plate 14a and the second terminal plate 14b.

  As shown in FIG. 4, the fuel cell stack 10 is incorporated in a vehicle fuel cell system 50. In the fuel cell system 50, power lines 52a and 52b are connected to the terminal plates 19a and 19b of the fuel cell stack 10, and a resistance unit 44 is connected to the power lines 52a and 52b via the contactors 54a and 54b. The In addition to the discharge resistor 48, the resistor unit 44 may be provided with a thermal fuse 56 as necessary in order to protect the resistor unit 44 and peripheral components from thermal damage.

  The vehicle drive motor unit 58 is connected to the power lines 52a and 52b via the contactors 54a and 54b. The vehicle drive motor unit 58 includes an inverter and a motor (not shown).

  As shown in FIGS. 1 and 4, the fuel cell stack 10 is provided with a component 60 that is relatively easily affected by heat on the side portion that is separated from the resistance unit 44. Examples of this type of component include a cell voltage monitoring unit and a current bypass unit.

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

  First, as shown in FIG. 3, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet communication hole 26a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet communication hole 28a. Further, a cooling medium such as pure water, ethylene glycol, or oil is supplied to the cooling medium inlet communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26a. The oxidant gas is supplied to the cathode side electrode 40 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow C direction.

  On the other hand, the fuel gas is introduced into the fuel gas flow path 34 of the second separator 24 from the fuel gas inlet communication hole 28a. The fuel gas is supplied to the anode side electrode 42 constituting the electrolyte membrane / electrode structure 20 while moving in the arrow C direction.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 40 and the fuel gas supplied to the anode side electrode 42 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done. Accordingly, as shown in FIG. 4, when the contactors 54c and 54d are closed, electric power is supplied from the fuel cell stack 10 to the vehicle drive motor unit 58, and the vehicle can travel.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 40 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b. On the other hand, the fuel gas consumed by being supplied to the anode side electrode 42 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to each cooling medium inlet communication hole 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and then flows in the direction of arrow B. The cooling medium is discharged from each cooling medium outlet communication hole 30b after the electrolyte membrane / electrode structure 20 is cooled.

  In this case, in this embodiment, the resistance unit 44 is disposed along the side portion 10 a of the fuel cell stack 10. In the fuel cell system 50, when starting or stopping, the contactors 54a and 54b are closed, and the discharge process (discharge process) of the fuel cell stack 10 is performed.

  At that time, in the resistance unit 44, the discharge resistor 48 generates heat, and the temperature of the fuel cell stack 10 can be raised. In particular, the resistance unit 44 is disposed on the side portion 10a where the cooling medium inlet communication hole 30a is provided, and a cooling medium (upstream cooling medium) that flows from the discharge resistor 48 through the cooling medium inlet communication hole 30a. ) Heat is transferred. On the other hand, the discharging resistor 48 can radiate heat well, suppresses overheating of the discharging resistor 48, and the size of the resistor unit 44 itself can be easily reduced.

  Therefore, when the temperature of the raised cooling medium flows through each cooling medium flow path 36 and is discharged to the cooling medium outlet communication hole 30b, each fuel cell 12 can be heated, and the entire fuel cell stack 10 is It becomes possible to raise the temperature uniformly.

  For example, when the operation of the fuel cell system 50 is stopped, the temperature of the fuel cell stack 10 is increased by increasing the temperature of the fuel cell stack 10 through the heat generated by the discharge resistor 48, so that the temperature decrease rate of the stopped fuel cell system 10 becomes moderate. For this reason, the time during which the fuel cell stack 10 is exposed to below freezing can be shortened. In addition, at the next start-up, the fuel cell stack 10 can be started from a relatively high temperature state, and the start-up time can be shortened.

  On the other hand, when the fuel cell system 50 is started, the temperature of the fuel cell stack 10 is raised through the heat generated by the discharge resistor 48, so that the temperature of the fuel cell stack 10 rises uniformly and quickly to a temperature suitable for power generation. be able to. Thereby, the start-up time of the fuel cell stack 10 is favorably shortened, and the startability of the fuel cell stack 10 is improved. In addition, since the rapid decrease in temperature is prevented by the heat generated by the discharge resistor 48, it is possible to suppress the deterioration of the fuel cell stack 10 due to the rapid decrease in temperature when stopped.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 10a ... Side part 12 ... Fuel cell 14a, 14b ... Terminal plate 16a, 16b ... Insulation plate 18a, 18b ... End plate 19a, 19b ... Terminal plate 20 ... Electrolyte membrane and electrode structure 22, 24 ... Separator 26a ... Oxidant gas inlet communication hole 26b ... Oxidant gas outlet communication hole 28a ... Fuel gas inlet communication hole 28b ... Fuel gas outlet communication hole 30a ... Cooling medium inlet communication hole 30b ... Cooling medium outlet communication hole 32 ... Oxidant gas flow Path 34 ... Fuel gas flow path 36 ... Cooling medium flow path 38 ... Solid polymer electrolyte membrane 40 ... Cathode side electrode 42 ... Anode side electrode 44 ... Resistance unit 46 ... Casing 48 ... Discharge resistance 50 ... Fuel cell system 58 ... Vehicle Drive motor unit 60 ... parts

Claims (2)

Provided with a fuel cell in which an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked, and a plurality of the fuel cells are stacked, and a reaction gas is passed along the stacking direction. A fuel cell stack provided with a reaction gas communication hole and a cooling medium communication hole through which a cooling medium flows.
A fuel cell stack, wherein a discharge resistor is disposed on a side portion provided with the cooling medium communication hole among side portions of the plurality of stacked fuel cells.   2. The fuel cell stack according to claim 1, wherein the discharge resistor has a meandering shape along the side portion of the side portion of the fuel cell where the cooling medium communication hole is provided on the inlet side. 3. A fuel cell stack, wherein the fuel cell stack is disposed.

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