JP5366793B2 - Fuel cell system - Google Patents

Description

  The present invention includes a fuel cell in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and a fuel cell stack in which a plurality of the fuel cells are stacked in a vertical direction, The present invention relates to a fuel cell system in which a plurality of the fuel cell stacks are arranged in parallel with electrodes reversed.

  For example, in a polymer electrolyte fuel cell, an electrolyte membrane / electrode structure (MEA) in which an anode side electrode and a cathode side electrode are disposed on both sides of an electrolyte membrane made of a polymer ion exchange membrane is sandwiched by separators. A unit cell is provided.

  Normally, this fuel cell is used as a fuel cell stack in which a predetermined number (for example, several tens to several hundreds) of unit cells are stacked in order to obtain a desired power generation. At that time, there is a problem that the length of the fuel cells in the stacking direction becomes considerably long, and the fuel gas cannot be uniformly supplied to each fuel cell. Therefore, a fuel cell system is used in which a plurality of fuel cell stacks are prepared and the fuel cell stacks are arranged in parallel with each other.

  For example, the fuel cell disclosed in Patent Document 1 includes stacked bodies 1a and 1b arranged in parallel with each other as shown in FIG. Although not shown in the drawings, the stacked bodies 1a and 1b are each formed by stacking a unit cell and a cooling member. The unit cell includes an electrolyte membrane, two gas diffusion electrodes that sandwich the electrolyte membrane from both sides to form a sandwich structure, and two collector electrodes that sandwich the sandwich structure from both sides.

  Terminal plates 2 and 3 are installed at the stacking ends of the stacked bodies 1a and 1b, respectively. The terminal board 2 is provided with an engaging projection 4 that protrudes toward the terminal board 3. The terminal plate 3 is provided with a convex portion 5 protruding toward the terminal plate 2, and the convex portion 5 is formed with an engaging concave portion 6 in which the engaging convex portion 4 can be engaged.

JP-A-8-171926

  However, in the above-mentioned Patent Document 1, terminal plates 2 and 3 having different shapes are individually installed at the stacked ends of the stacked bodies 1a and 1b. For this reason, there are problems that the number of parts increases and the manufacturing cost increases. In addition, it is necessary to engage the engaging convex portion 4 with the engaging concave portion 6, and there is a problem that the assembly work of the fuel cell stack becomes complicated.

  The present invention solves this type of problem, and an object thereof is to provide a fuel cell stack capable of electrically connecting fuel cell stacks arranged in parallel with each other with a simple and economical configuration. To do.

  The present invention includes a fuel cell in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and a fuel cell stack in which a plurality of the fuel cells are stacked in a vertical direction, The present invention relates to a fuel cell system in which a plurality of the fuel cell stacks are arranged in parallel with electrodes reversed.

  In this fuel cell system, a common terminal plate is disposed at a lower portion of an adjacent fuel cell stack, and the common terminal plate has a plurality of current collectors facing each electrode surface of the adjacent fuel cell stack. And a connecting portion that is integrally formed with the plurality of current collecting portions and disposed between the adjacent fuel cell stacks, and the width dimension of the connecting portion is set smaller than the width dimension of the current collecting portion. ing.

  In addition, the fuel cell stack includes three fluid supply communication holes and three fluid discharge communication holes that allow the fluid that is the oxidant gas, the fuel gas, and the cooling medium to flow in the vertical direction. The fluid supply communication hole and the three fluid discharge communication holes are arranged in a plane that is circulated, and the connecting portion is between the fluid supply communication holes, between the fluid discharge communication holes, or the fluid supply communication hole. It is preferable to be disposed between the fluid discharge communication hole.

  Furthermore, it is preferable that a cooling medium inlet communication hole that is a fluid supply communication hole and a cooling medium outlet communication hole that is a fluid discharge communication hole are disposed on both sides of the connection portion.

  Furthermore, it is preferable that the connecting portion is integrally provided at the center portion in the width direction of the two current collecting portions.

  In addition, the fuel cell system preferably includes an insulating plate adjacent to the common terminal plate, and the insulating plate is preferably formed with a recess that accommodates a part of the current collector and the connecting portion.

  Furthermore, this fuel cell system preferably includes a box that integrally accommodates a plurality of fuel cell stacks.

  According to the present invention, a common terminal plate is disposed below the adjacent fuel cell stack, and the common terminal plate is integrally provided with a connecting portion that functions as a bus bar. Therefore, the common terminal plate is configured such that each current collecting portion and the connecting portion are integrally formed. Therefore, compared to a configuration in which a plurality of independent terminal plates are electrically connected by a power cable or the like, the periphery of the connecting portion is arranged. The degree of freedom in layout is improved.

  In addition, since each current collecting portion and the connecting portion are integrally formed, the number of parts is reduced and the configuration of the common terminal plate itself is simplified. In addition, since the common terminal plate is obtained by punching a plate, the manufacturing cost of the common terminal plate can be easily reduced. Further, space saving is achieved, and the fuel cell stack can be miniaturized so that the entire fuel cell system can be miniaturized.

1 is a schematic perspective view of a fuel cell system according to an embodiment of the present invention. FIG. 3 is a perspective view illustrating a main part of first and second fuel cell stacks constituting the fuel cell system. FIG. 3 is an exploded perspective view of a fuel cell that constitutes the first fuel cell stack. It is explanatory drawing of the common terminal plate which comprises the said fuel cell system. 2 is a perspective view of a fuel cell according to Patent Document 1. FIG.

  As shown in FIG. 1, a fuel cell system 10 according to an embodiment of the present invention includes a plurality of, for example, two sets of first and second fuel cell stacks having the same configuration arranged in parallel with each other and reversed in polarity. 12A and 12B are provided.

  The first fuel cell stack 12A is configured by stacking a plurality of fuel cells 14A in the vertical direction (direction of arrow A). As shown in FIGS. 1 and 2, a common terminal plate 16, an insulating plate 18a, and an end plate 20a are disposed at the lower end in the stacking direction of the fuel cell 14A. A terminal plate 16a, an insulating plate 18b, and an end plate 20b are disposed at the upper end in the stacking direction of the fuel cell 14A.

  The end plates 20a and 20b are clamped in the stacking direction by a plurality of tie rods 19, and a clamping load is applied to the plurality of fuel cells 14A. The end plates 20a and 20b can be fixed by a long flat plate-like connecting member that is integrally stretched between them.

  As shown in FIG. 3, in the fuel cell 14 </ b> A, an electrolyte membrane / electrode structure (MEA) 21 is sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 are made of, for example, a carbon separator, but may be made of a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate.

  One end edge of the fuel cell 14A in the direction of arrow B (horizontal direction in FIG. 3) communicates with each other in the direction of arrow A, which is the stacking direction, and oxidant for supplying an oxidant gas, for example, an oxygen-containing gas An agent gas inlet communication hole 26a and a fuel gas inlet communication hole 28a for supplying a fuel gas, for example, a hydrogen-containing gas, are arranged in an arrow C direction (horizontal direction).

  The other end edge of the fuel cell 14A in the direction of arrow B communicates with each other in the direction of arrow A, the fuel gas outlet communication hole 28b for discharging the fuel gas, and the oxidant gas for discharging the oxidant gas. Outlet communication holes 26b are arranged in the direction of arrow C.

  A pair of cooling medium inlet communication holes 30a, 30a for supplying a cooling medium and a pair of cooling medium outlet communication holes 30b, 30b for discharging the cooling medium are provided at both ends of the fuel cell 14A in the direction of arrow C. 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 21.

  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 21.

  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 cell 14A adjacent to each other. A flow path 36 is provided.

  The first seal member 38 is integrally or individually provided on the surfaces 22 a and 22 b of the first separator 22, and the second seal member 40 is integrally formed on the surfaces 24 a and 24 b of the second separator 24. Or it is provided separately.

  The first and second sealing members 38 and 40 are, for example, EPDM, NBR, fluorine rubber, silicon rubber, fluorosilicone rubber, butyl rubber, natural rubber, styrene rubber, chloroprene, or acrylic rubber or the like, cushioning material, Alternatively, a packing material is used.

  The electrolyte membrane / electrode structure 21 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 44 and an anode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The cathode side electrode 44 and the anode side electrode 46 are formed by uniformly applying a gas diffusion layer made of carbon paper or the like and porous carbon particles having a platinum alloy supported 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 42.

  The second fuel cell stack 12B is configured by stacking a plurality of fuel cells 14B in the vertical direction (direction of arrow A). As shown in FIGS. 1 and 2, a common terminal plate 16, an insulating plate 18a, and an end plate 20a are disposed at the lower end in the stacking direction of the fuel cell 14B. A terminal plate 16b, an insulating plate 18b, and an end plate 20b are disposed at the upper end in the stacking direction of the fuel cell 14B.

  The fuel cells 14A and 14B constituting the first and second fuel cell stacks 12A and 12B have exactly the same configuration. In order to reverse the polarities of the fuel cells 14A and 14B, for example, the fuel cell 14B is The fuel cell 14A is inverted 180 ° around a horizontal axis extending in the longitudinal direction (arrow B direction) (see FIG. 2).

  As shown in FIGS. 2 and 4, the common terminal plate 16 includes two (a plurality of) current collectors 50a and 50b facing the electrode surfaces of the adjacent first and second fuel cell stacks 12A and 12B, A connecting portion 52 that is integrally formed with the current collecting portions 50a and 50b and disposed between the adjacent first and second fuel cell stacks 12A and 12B is provided.

  The connecting portion 52 has a function as a bus bar, and is integrally provided at the center in the width direction of the two current collecting portions 50a and 50b, and the width dimension of the connecting portion 52 is the current collecting portion 50a. , 50b is set smaller than the width dimension.

  The current collectors 50a and 50b include an oxidant gas inlet communication hole 26a, a fuel gas inlet communication hole 28a, an oxidant gas outlet communication hole 26b, a fuel gas outlet communication hole 28b, a cooling medium inlet communication hole 30a and 30a, and a cooling medium outlet. It arrange | positions in the surface circulated by the communicating holes 30b and 30b. The connecting portion 52 is disposed between the cooling medium inlet communication hole 30a and the cooling medium outlet communication hole 30b, but is not limited to this, and can be disposed between any two communication holes.

  As shown in FIG. 2, each insulating plate 18 a is formed with a concave portion 54 a for accommodating the current collecting portions 50 a and 50 b and a concave portion 54 b for accommodating a part of the connecting portion 52. Each insulating plate 18b is formed with a recess 56 for accommodating the terminal plates 16a and 16b, while the terminal plates 16a and 16b are formed with terminal terminals 58a and 58b having different polarities protruding upward. The

  The end plate 20a includes an oxidant gas inlet communication hole 26a, a fuel gas inlet communication hole 28a, an oxidant gas outlet communication hole 26b, a fuel gas outlet communication hole 28b, cooling medium inlet communication holes 30a and 30a, and a cooling medium outlet communication hole. While a manifold (not shown) communicating with 30b and 30b is provided, the end plate 20b is formed in a planar shape. The first and second fuel cell stacks 12A and 12B are integrally accommodated in the box 60 (see FIG. 1).

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

  First, the first and second fuel cell stacks 12A and 12B are cooled through a manifold (not shown) such as an oxidant gas such as an oxygen-containing gas, a fuel gas such as a hydrogen-containing gas, and pure water, ethylene glycol, or oil. Medium is supplied. As shown in FIG. 3, in the fuel cell 14A, the oxidant gas is supplied to the oxidant gas inlet communication hole 26a and the fuel gas is supplied to the fuel gas inlet communication hole 28a. Further, the cooling medium is supplied to the pair of cooling medium inlet communication holes 30a and 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 44 constituting the electrolyte membrane / electrode structure 21 while moving in the arrow B 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 46 constituting the electrolyte membrane / electrode structure 21 while moving in the arrow B direction.

  Therefore, in the electrolyte membrane / electrode structure 21, the oxidant gas supplied to the cathode side electrode 44 and the fuel gas supplied to the anode side electrode 46 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 44 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 electrode 46 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b.

  The cooling medium supplied to the pair of cooling medium inlet communication holes 30a and 30a is introduced into the cooling medium flow path 36 between the first and second separators 22 and 24 and once flows in a direction close to each other. Circulates in the direction of arrow C. After cooling the electrolyte membrane / electrode structure 21, the cooling medium is distributed to the pair of cooling medium outlet communication holes 30b and 30b and discharged.

  In the fuel cell 14B constituting the second fuel cell stack 12B, as in the fuel cell 14A, the oxidant gas is supplied to the oxidant gas inlet communication hole 26a and the fuel gas inlet communication hole 28a is fueled. Gas is supplied. Further, the cooling medium is supplied to the pair of cooling medium inlet communication holes 30a and 30a.

  Therefore, in the fuel cell 14B, power is generated by being consumed by an electrochemical reaction in the electrode catalyst layer. As a result, the terminal terminals 58a and 58b have different polarities and can extract electric power.

  In this case, in the present embodiment, the common terminal plate 16 includes two current collectors 50a and 50b facing each electrode surface of the adjacent first and second fuel cell stacks 12A and 12B, and the current collector 50a, 50b, and a connecting portion 52 that functions as a bus bar disposed between the adjacent first and second fuel cell stacks 12A and 12B.

  For this reason, the common terminal plate 16 is configured such that the current collectors 50a and 50b and the connecting part 52 are integrated, so that the two independent terminal plates are electrically connected to each other by a power cable or the like. Since an extra space is not required, an effect that the degree of freedom of layout around the connecting portion 52 is improved can be obtained.

  Moreover, since each of the current collectors 50a, 50b and the connecting part 52 are integrated, the number of parts is reduced and the configuration of the common terminal plate 16 itself is simplified. In addition, since the common terminal plate 16 is obtained by stamping a plate, the manufacturing cost of the common terminal plate 16 can be easily reduced. Furthermore, space saving is achieved, and miniaturization of the entire fuel cell system 10 can be performed by miniaturization of the first and second fuel cell stacks 12A and 12B.

  Furthermore, the first and second fuel cell stacks 12 </ b> A and 12 </ b> B are accommodated in the box 60 in a state of being connected by the common terminal plate 16. Therefore, the connection part 52 of the common terminal plate 16 is not exposed to the outside, and there is an advantage that a dedicated waterproof structure is unnecessary and it is economical.

  In addition, each of the current collectors 50a and 50b and the connecting part 52 are integrated, and has a substantially H shape. Accordingly, the oxidant gas inlet communication hole 26a, the fuel gas inlet communication hole 28a, the oxidant gas outlet communication hole 26b, the fuel gas outlet communication hole 28b, the cooling medium inlet communication hole 30a, and the cooling medium outlet communication hole 30b are connected to the connecting portion 52. The layout can be easily improved.

DESCRIPTION OF SYMBOLS 10 ... Fuel cell system 12A, 12B ... Fuel cell stack 14A, 14B ... Fuel cell 16 ... Common terminal plate 16a, 16b ... Terminal plate 18a, 18b ... Insulating plate 20a, 20b ... End plate 21 ... 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 42 ... solid polymer electrolyte membrane 44 ... cathode side electrode 46 ... anode side electrode 50a, 50b ... current collecting part 52 ... connecting parts 54a, 54b, 56 ... Recess 60 ... Box

Claims (4)

A fuel cell in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked; a fuel cell stack in which a plurality of the fuel cells are stacked in a vertical direction; and a plurality of the fuels A fuel cell system in which the battery stacks are arranged in parallel with the electrodes reversed,
A common terminal plate is disposed below the adjacent fuel cell stack, and
The common terminal plate includes a plurality of current collectors facing each electrode surface of the adjacent fuel cell stack,
A plurality of current collectors integrally formed and connected between adjacent fuel cell stacks;
Provided,
The width dimension of the connection part is set smaller than the width dimension of the current collector part ,
The fuel cell stack is provided with three fluid supply communication holes and three fluid discharge communication holes for allowing a fluid as an oxidant gas, a fuel gas, and a cooling medium to flow in the vertical direction, and
The current collector is disposed in a plane that is circulated by the three fluid supply communication holes and the three fluid discharge communication holes, and the connection portion is disposed between the fluid supply communication holes and the fluid discharge communication. Between the holes or between the fluid supply communication hole and the fluid discharge communication hole,
Wherein on both sides of the connecting portion, the fuel cell system characterized Rukoto and coolant discharge passages said a fluid supply passage and the cooling medium supply passage is the fluid discharge passages are disposed. The fuel cell system according to claim 1, wherein said connecting portion, the fuel cell system characterized in that it is formed integrally with the center in the width direction of two of the current collector. The fuel cell system according to claim 1 or 2 , further comprising an insulating plate adjacent to the common terminal plate,
The fuel cell system according to claim 1, wherein the insulating plate is formed with a recess that accommodates a part of the current collector and the connection. The fuel cell system according to any one of claims 1 to 3 , further comprising a box that integrally accommodates the plurality of fuel cell stacks.

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