JP5313548B2 - Fuel cell stack - Google Patents

Description

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a laminate in which a plurality of the unit cells are stacked is interposed between a pair of rectangular end plates. The present invention relates to a fuel cell stack configured to be sandwiched.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. A fuel cell is configured by sandwiching an electrolyte membrane / electrode structure in which an anode side electrode and a cathode side electrode are disposed on both sides of the electrolyte membrane with a separator.

  Normally, this fuel cell is used as a fuel cell stack in which a predetermined number (for example, several tens to several hundreds) is stacked in order to obtain a desired power generation. In this fuel cell stack, the stacked fuel cells need to be reliably pressurized and held in order to prevent an increase in the internal resistance of the fuel cell and a decrease in the sealing performance of the reaction gas.

  Therefore, for example, a fastening structure of a fuel cell stack disclosed in Patent Document 1 is known. In this prior art, as shown in FIG. 6, a fuel cell stack 1 in which membrane electrode assemblies and separator plates are alternately stacked is provided, and end plates 2 a and 2 b are disposed at both ends of the fuel cell stack 1. ing.

  A first fastening band 3 and a second fastening band 4 are attached to the fuel cell stack 1. The first fastening band 3 extends along two parallel side surfaces of the fuel cell stack 1, while the second fastening band 4 extends along the other two parallel side surfaces of the fuel cell stack 1. doing. Both ends of the first fastening band 3 are fixed to the end plate 2a via bolts (not shown), and both ends of the second fastening band 4 are fixed to the end plate 2b via bolts (not shown).

JP 2005-142145 A

  By the way, in the fuel cell stack 1 described above, it is desired that the end plates 2a and 2b be formed thin in order to reduce the weight. However, particularly in the case of rectangular (vertically long) end plates 2a and 2b, when the tightening load is applied in the stacking direction by the first fastening band 3 and the second fastening band 4, the end plates 2a and 2b are in the longitudinal direction. There is a problem that it becomes easy to bend along.

  The present invention solves this type of problem, and provides a fuel cell stack capable of reducing the weight of the end plate and satisfactorily suppressing the deformation of the rectangular end plate due to a tightening load. With the goal.

  The present invention includes a unit cell in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte is sandwiched between separators, and a laminate in which a plurality of the unit cells are stacked is interposed between a pair of rectangular end plates. The present invention relates to a fuel cell stack configured to be sandwiched.

At least one of the rectangular end plates is provided with a communication port through which the reaction gas or the cooling medium is introduced or led out in the thickness direction, and is cut out in the thickness direction to provide a lightening portion. vent section, the long side direction of the thickness direction of the depth I suited from a central portion in the long side direction end sides of the rectangular end plates is set continuously or intermittently increased.

  Furthermore, the fuel cell stack preferably includes a box-shaped casing in which an end plate is an end plate, a plurality of side plates are disposed on a side portion of the laminate, and the end plate and the side plate are connected by a connecting pin.

  In the present invention, the rectangular end plate is notched in the thickness direction and is provided with a thinned portion, so that the rigidity of the rectangular end plate itself can be maintained and the weight can be reduced.

  Moreover, the thickness of the thinned portion varies along the long side direction of the rectangular end plate. Accordingly, the rectangular end plate can be configured such that a portion that is not easily deformed when a tightening load is applied is thinner than a portion that is easily deformed. As a result, the rectangular end plate has a simple configuration and can be further reduced in weight as a whole.

  FIG. 1 is a partially exploded schematic perspective view of a fuel cell stack 10 according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional side view of the fuel cell stack 10.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of unit cells 12 are stacked in the horizontal direction (arrow A direction). A terminal plate 16a, an insulating plate 18 and an end plate 20a are sequentially disposed at one end in the stacking direction (arrow A direction) of the stacked body 14 toward the outside. At the other end in the stacking direction of the stacked body 14, a terminal plate 16b, an insulating spacer member 22 (the insulating plate 18 may be used) and an end plate 20b are sequentially disposed outward. The fuel cell stack 10 is integrally held by a box-shaped casing 24 including end plates (rectangular end plates) 20a and 20b configured in a vertically long rectangular shape as end plates.

  As shown in FIGS. 2 and 3, each unit cell 12 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 30, and a thin plate-shaped first and second sandwiching the electrolyte membrane / electrode structure 30. Second metal separators 32 and 34 are provided. Instead of the first and second metal separators 32 and 34, carbon separators may be used.

  In order to supply an oxidant gas, for example, an oxygen-containing gas, to one end edge (upper edge) in the long side direction (the arrow C direction in FIG. 3) of the unit cell 12 in communication with each other in the arrow A direction. The oxidant gas supply communication hole 36a and a fuel gas supply communication hole 38a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge (lower end edge) of the unit cell 12 in the long side direction communicates with each other in the direction of arrow A, and discharges the fuel gas discharge communication hole 38b for discharging the fuel gas and the oxidant gas. For this purpose, an oxidant gas discharge communication hole 36b is provided.

  A cooling medium supply communication hole 40a for supplying a cooling medium is provided at one end edge of the unit cell 12 in the short side direction (arrow B direction), and the other end edge of the unit cell 12 in the short side direction. Is provided with a cooling medium discharge communication hole 40b for discharging the cooling medium.

  The electrolyte membrane / electrode structure 30 includes, for example, a solid polymer electrolyte membrane 42 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 44 and a cathode side electrode 46 that sandwich the solid polymer electrolyte membrane 42. With.

  The anode side electrode 44 and the cathode side electrode 46 are uniformly coated with 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. And an electrode catalyst layer (not shown) formed. The electrode catalyst layers are formed on both surfaces of the solid polymer electrolyte membrane 42.

  On the surface 32a of the first metal separator 32 facing the electrolyte membrane / electrode structure 30, a fuel gas flow channel 48 that communicates the fuel gas supply communication hole 38a and the fuel gas discharge communication hole 38b is formed along the arrow C direction. Is done. On the surface 32b of the first metal separator 32, a cooling medium flow path 50 that communicates the cooling medium supply communication hole 40a and the cooling medium discharge communication hole 40b is formed along the arrow B direction.

  The surface 34a of the second metal separator 34 facing the electrolyte membrane / electrode structure 30 is provided with an oxidant gas flow path 52 along the direction of arrow C. The oxidant gas flow path 52 is provided with an oxidant gas supply. The communication hole 36a communicates with the oxidant gas discharge communication hole 36b. A cooling medium flow path 50 is integrally formed on the surface 34 b of the second metal separator 34 so as to overlap the surface 32 b of the first metal separator 32.

  A first seal member 54 is integrally formed on the surfaces 32 a and 32 b of the first metal separator 32 around the outer peripheral edge of the first metal separator 32. A second seal member 56 is integrally formed on the surfaces 34 a and 34 b of the second metal separator 34 around the outer peripheral edge of the second metal separator 34.

  As shown in FIG. 2, a seal 57 is interposed between the first and second seal members 54 and 56 in order to prevent the outer periphery of the solid polymer electrolyte membrane 42 from directly contacting the casing 24. Is done.

  As shown in FIG. 1, rod-shaped terminal portions 58a and 58b projecting in the stacking direction are provided above the center portions of the terminal plates 16a and 16b. The terminal portions 58a and 58b protrude to the outside through holes 59a and 59b formed in the center portions of the end plates 20a and 20b in the longitudinal direction and the short direction, and the terminal portions 58a and 58b include, for example, A load such as a vehicle driving motor is connected.

  The casing 24 is an angle member that connects end plates 20a and 20b, which are end plates, a plurality of side plates 60a to 60d disposed on the side of the laminated body 14, and end portions of the side plates 60a to 60d that are close to each other. 62a to 62d, and connecting pins 64a and 64b having different lengths for connecting the end plates 20a and 20b and the side plates 60a to 60d.

  The side plates 60a to 60d are made of, for example, a thin metal plate. The side plates 60a to 60d are fixed to each other via angle members 62a to 62d and bolts 65, and the casing 24 is configured (see FIG. 4).

  On the upper and lower sides (short sides) of the end plates 20a and 20b, one first support portion 66a and 66b is formed to protrude, and on each side (long side) on both sides, two first supports are provided. Portions 66c and 66d are formed to protrude.

  Three second support portions 70a and 70b are formed at both ends in the longitudinal direction (arrow A direction) of the side plates 60a and 60c arranged on both sides in the arrow B direction of the laminated body 14, respectively. Two second support portions 72a and 72b are formed at both ends in the longitudinal direction of the side plates 60b and 60d disposed on the upper and lower sides of the laminated body 14, respectively.

  As shown in FIG. 4, between the second support portions 70a, 70b of the side plates 60a, 60c, first support portions 66c, 66d on both sides of the end plates 20a, 20b are arranged. A long connecting pin 64a is integrally inserted.

  Similarly, the second support portions 72a and 72b of the side plates 60b and 60d are alternately arranged with the first support portions 66a and 66b on the upper and lower sides of the end plates 20a and 20b, and a short connecting pin 64b is provided on these. Inserted integrally.

  As shown in FIG. 1, the end plate 20a has an oxidant gas inlet 76a communicating with the oxidant gas supply communication hole 36a, a fuel gas inlet 78a communicated with the fuel gas supply communication hole 38a, and an oxidant gas discharge communication hole 36b. An oxidant gas outlet 76b communicating with the fuel gas and a fuel gas outlet 78b communicating with the fuel gas discharge communicating hole 38b are provided.

  The end plate 20b is provided with a cooling medium inlet 80a that communicates with the cooling medium supply communication hole 40a and a cooling medium outlet 80b that communicates with the cooling medium discharge communication hole 40b.

  As shown in FIG. 4 and FIG. 5, at least the outwardly facing surface of the end plate 20a is notched in the thickness direction, and a plurality of first cutout portions 82a, second cutout portions 82b, and third cutouts are respectively provided. A punched portion 82c and a fourth cutout portion 82d are provided.

  The first lightening part 82a is provided in the range surrounding the hole 59a at the approximate center of the end plate 20a, and the second lightening part 82b is formed on both upper and lower sides of the first lightening part 82a. Is done. On the upper and lower sides of the second cutout portion 82b, a third cutout portion 82c is provided between the oxidant gas inlet 76a and the fuel gas inlet 78a and between the oxidant gas outlet 76b and the fuel gas outlet 78b, respectively. Are formed two by two. A fourth lightening part 82d is formed outside the third lightening part 82c in the width direction (arrow B direction).

  As shown in FIG. 5, the depth t1 in the thickness direction of the first cutout portion 82a, the depth t2 in the thickness direction of the second cutout portion 82b, and the depth in the thickness direction of the third cutout portion 82c. The thickness t4 and the depth t4 in the thickness direction of the fourth cutout portion 82d are set to have a relationship of t1 <t2 <t3 <t4. In addition, although the 1st thickness reduction part 82a-the 4th thickness reduction part 82d are set so that depth t1-t4 of thickness direction may become large intermittently, it sets so that it may become large continuously, for example May be. The short direction is set to a certain depth. The lightening in the short direction is divided into a plurality of regions by ribs.

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

  As shown in FIG. 4, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas inlet 76a of the end plate 20a, and a fuel gas such as a hydrogen-containing gas is supplied to the fuel gas inlet 78a. Further, a cooling medium such as pure water or ethylene glycol is supplied to the cooling medium inlet 80a of the end plate 20b (see FIG. 1).

  Therefore, in the stacked body 14, the oxidant gas is supplied to the oxidant gas supply communication hole 36a, the fuel gas supply communication hole 38a, and the cooling medium supply communication hole 40a with respect to the plurality of unit cells 12 stacked in the arrow A direction. The fuel gas and the cooling medium are supplied in the direction of arrow A.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 52 of the second metal separator 34 through the oxidant gas supply communication hole 36 a, and along the cathode side electrode 46 of the electrolyte membrane / electrode structure 30. Move. On the other hand, the fuel gas is introduced into the fuel gas channel 48 of the first metal separator 32 from the fuel gas supply communication hole 38 a and moves along the anode side electrode 44 of the electrolyte membrane / electrode structure 30.

  Therefore, in each electrolyte membrane / electrode structure 30, the oxidant gas supplied to the cathode side electrode 46 and the fuel gas supplied to the anode side electrode 44 are consumed by an electrochemical reaction in the electrode catalyst layer, Power generation is performed.

  Next, the oxidant gas consumed by being supplied to the cathode side electrode 46 flows along the oxidant gas discharge communication hole 36b, and is then discharged to the outside from the oxidant gas outlet 76b of the end plate 20a (FIG. 4). reference). Similarly, the fuel gas consumed by being supplied to the anode side electrode 44 is discharged to the fuel gas discharge communication hole 38b and flows, and is discharged to the outside from the fuel gas outlet 78b of the end plate 20a.

  The cooling medium is introduced into the cooling medium flow path 50 between the first and second metal separators 32 and 34 from the cooling medium supply communication hole 40a, and flows along the arrow B direction. After cooling the electrolyte membrane / electrode structure 30, the cooling medium moves through the cooling medium discharge communication hole 40b and is discharged from the cooling medium outlet 80b of the end plate 20b (see FIG. 1).

  In this case, in this embodiment, as shown in FIGS. 4 and 5, the end plate 20 a is notched in the thickness direction, and a plurality of first to fourth cutout portions 82 a to 82 d are provided. And the 1st thinning part 82a arrange | positioned in the center part of the end plate 20a is comprised by the depth t1 of the thickness direction at a comparatively shallow groove | channel.

  For this reason, when a tightening load is applied to the rectangular end plate 20a, it is possible to maintain the rigidity of the central portion that is particularly easily deformed. Therefore, it is possible to suppress the deformation of the end plate 20a in the long side direction (arrow C direction) to a specified value or less and to reduce the weight.

  Moreover, in the end plate 20a, as it goes to the portion that is difficult to be deformed by the tightening load, that is, in the order of the second lightening part 82b, the third lightening part 82c, and the fourth lightening part 82d, The depths t2, t3, and t4 are set to have a relationship of t1 <t2 <t3 <t4. Thereby, the effect that weight reduction can be achieved more reliably as the whole end plate 20a is acquired.

  Furthermore, the thickness of the end plate 20a is kept constant over the entire plane. For this reason, there exists an advantage that size reduction and weight reduction of the fuel cell stack 10 whole are easily performed with a simple structure.

  The end plate 20b can be configured in the same manner as the above end plate 20a. In addition, the fuel cell stack 10 is configured by housing the laminate 14 in a box-shaped casing 24. For example, a configuration in which the end plates 20a and 20b are clamped and held by a tie rod (not shown) may be employed. Is possible.

  Further, the end plates 20a and 20b may be thinned on the surface side facing the terminal plates 16a and 16b (surface side opposite to the embodiment). Thereby, the outer side of the end plates 20a and 20b is formed in a plane.

1 is a partially exploded schematic perspective view of a fuel cell stack according to an embodiment of the present invention. It is a partial cross section side view of the said fuel cell stack. It is a disassembled perspective explanatory drawing of the unit cell which comprises the said fuel cell stack. It is a perspective view of the fuel cell stack. FIG. 5 is a cross-sectional view of the end plate constituting the fuel cell stack, taken along line VV in FIG. 4. It is a perspective explanatory view of the fastening structure of the fuel cell stack disclosed in Patent Document 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fuel cell stack 12 ... Unit cell 14 ... Laminated body 16a, 16b ... Terminal plate 18 ... Insulating plate 20a, 20b ... End plate 22 ... Spacer member 24 ... Casing 30 ... Electrolyte membrane and electrode structure 32, 34 ... Metal separator DESCRIPTION OF SYMBOLS 42 ... Solid polymer electrolyte membrane 44 ... Anode side electrode 46 ... Cathode side electrode 48 ... Fuel gas flow path 50 ... Cooling medium flow path 52 ... Oxidant gas flow path 60a-60d ... Side plate 64a, 64b ... Connecting pin 82a-82d ... Meat removal part

Claims (3)

A unit cell in which a pair of electrodes are provided on both sides of an electrolyte and an electrolyte / electrode structure is sandwiched between separators, and a laminate in which a plurality of the unit cells are stacked is sandwiched between a pair of rectangular end plates. A fuel cell stack,
At least one of the rectangular end plates is provided with a communication port through which the reaction gas or the cooling medium is introduced or led out in the thickness direction, and is cut out in the thickness direction to provide a lightening portion,
The lightening portion, said rectangular end plate longitudinal direction from the central portion of the thickness direction I suited to the long side direction end sides depth is set continuously or intermittently increased characterized Rukoto And fuel cell stack. The fuel cell stack according to claim 1 Symbol placement, the fuel cell stack, wherein the rectangular end plates end plates, as well as arranging a plurality of side plates on the side of the laminate, the end plate and the side plate is coupled A fuel cell stack comprising a box-shaped casing connected by pins. The fuel cell stack according to claim 1 or 2 , wherein a plurality of the communication ports are provided,
The fuel cell stack is characterized in that the lightening portion is formed between the communication ports.

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