JP4928251B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack in which a laminate in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte and a separator are laminated is disposed between insulating members.

  For example, a polymer electrolyte fuel cell employs an electrolyte membrane (electrolyte) made of a polymer ion exchange membrane. 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 includes a unit cell sandwiched by separators. Usually, a fuel cell stack is formed by stacking a plurality of unit cells.

  By the way, in the fuel cell stack, it is necessary to prevent water from entering from the outside and causing electric leakage. On the other hand, in the fuel cell stack, various seal members are used to seal the fuel gas, the oxidant gas, and the cooling medium. However, the fuel gas that has permeated the seal member may remain in the fuel cell stack. There is.

  Thus, for example, a fuel cell case disclosed in Patent Document 1 is known. As shown in FIG. 11, the fuel cell stack 2 is accommodated in the case 1, and the ventilation port 3 provided at the uppermost portion of the case 1 does not transmit water but transmits gases such as hydrogen and air. The hydrogen permeable membrane 4 is sealed.

JP 2002-367647 A (FIG. 1)

  However, in Patent Document 1 described above, since the fuel cell stack 2 is accommodated in the case 1, the outer dimensions of the case 1 are larger than the dimensions of the fuel cell stack 2, and the case 1 itself is equivalent. There is a problem that it becomes heavy.

  The present invention solves this type of problem, and it is possible to reduce the size and weight of the entire fuel cell stack, improve waterproofness and dustproofness, and allow the reaction gas to be diluted and discharged well outside. An object is to provide a possible fuel cell stack.

  The present invention relates to a fuel cell stack in which a laminate in which an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte and a separator are laminated is disposed between insulating members.

  The fuel cell stack includes a cylindrical cover member that covers the laminate and circulates at least in a range sandwiched between insulating members, and the cylindrical cover member is impermeable to liquid and permeable to gas. A gas permeable membrane having properties is provided.

  Moreover, it is preferable that a cylindrical cover member is provided with the sealing member which has elasticity in the part engaged with an insulating member.

  Furthermore, it is preferable that the insulating member is sandwiched between the pair of end plates, and the laminated body and the cylindrical cover member are surrounded by a casing having the pair of end plates as end plates.

  Furthermore, it is preferable that the insulating member is sandwiched between a pair of end plates, and the pair of end plates are clamped and held by a fastening member so as to be expandable and contractable in the stacking direction.

  In addition, the cylindrical cover member is preferably made of an anisotropic material and has maximum stretchability along the stacking direction.

  In the present invention, it is only necessary to circulate at least the range sandwiched between the insulating members by the cylindrical cover member. Therefore, in order to prevent water, dust, etc. from entering the inside of the fuel cell stack from the outside, it is not necessary to accommodate the fuel cell stack in, for example, a sealed container. As a result, the entire fuel cell stack can be easily reduced in weight and size, and the waterproofness and dustproofness inside the fuel cell stack can be improved.

  In addition, when the reaction gas leaks from the inside of the fuel cell stack, the cylindrical cover member that circulates around the stacked body secures a sufficient area, so that the reaction gas can be quickly discharged to the outside. . Therefore, the reaction gas can be diluted well outside the fuel cell stack, and for example, a ventilation device or the like is not required, which is economical.

  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 partially exploded perspective view of the fuel cell stack 10.

  The fuel cell stack 10 includes a stacked body 12, and the stacked body 12 is accommodated in a casing 14. The stacked body 12 includes a plurality of unit cells 16 stacked in the horizontal direction (arrow A direction), and the casing 14 is formed at both ends in the stacking direction via terminal plates 18a and 18b and insulating plates 20a and 20b. End plates 22a and 22b are disposed.

  As shown in FIG. 3, each unit cell 16 includes an electrolyte membrane / electrode structure (electrolyte / electrode structure) 26, and first and second separators having a thin plate shape that sandwich the electrolyte membrane / electrode structure 26. 28 and 30 and is configured to be vertically long. As the first and second separators 28 and 30, for example, a metal separator or a carbon separator processed into a wave shape is used.

  One end edge (upper end edge) of the unit cell 16 in the long side direction (arrow C direction) communicates with each other in the arrow A direction to supply an oxidant gas, for example, an oxygen-containing gas. A supply communication hole 32a, a cooling medium supply communication hole 34a for supplying a cooling medium, and a fuel gas supply communication hole 36a for supplying a fuel gas, for example, a hydrogen-containing gas, are provided.

  The other end edge (lower end edge) in the long side direction of the unit cell 16 communicates with each other in the direction of the arrow A, and the fuel gas discharge communication hole 36b for discharging the fuel gas, for discharging the cooling medium. A cooling medium discharge communication hole 34b and an oxidant gas discharge communication hole 32b for discharging the oxidant gas are provided.

  The electrolyte membrane / electrode structure 26 includes, for example, a solid polymer electrolyte membrane 38 in which a perfluorosulfonic acid thin film is impregnated with water, and an anode side electrode 40 and a cathode side electrode 42 that sandwich the solid polymer electrolyte membrane 38. With.

  On the surface of the first separator 28 facing the electrolyte membrane / electrode structure 26, a fuel gas flow path 44 that connects the fuel gas supply communication hole 36a and the fuel gas discharge communication hole 36b is formed. The fuel gas channel 44 is constituted by, for example, a groove portion extending in the direction of arrow C.

  The surface of the second separator 30 facing the electrolyte membrane / electrode structure 26 is provided with, for example, an oxidant gas flow path 46 composed of a groove extending in the direction of arrow C. The oxidant gas supply communication hole 32a and the oxidant gas discharge communication hole 32b communicate with each other. On the other surface of the second separator 30, a cooling medium flow path 48 is integrally formed so as to overlap the first separator 28. Although not shown, the first and second separators 28 and 30 are integrally formed or interposed with a seal member set in a desired shape.

  As shown in FIG. 4, the fuel cell stack 10 includes a cylindrical cover member 50 that covers the stacked body 12 and circulates in a range sandwiched between the insulating plates 20 a and 20 b. The cylindrical cover member 50 is provided with a gas permeable membrane that is impermeable to liquid and permeable to gas. The gas permeable membrane is composed of, for example, a porous membrane having a fiber structure obtained by heating and stretching polytetrafluoroethylene (PTFE). The cylindrical cover member 50 has anisotropy and has maximum stretchability along the stacking direction.

  Thick portions 52 a and 52 b are formed at both ends of the cylindrical cover member 50. The thick portions 52a and 52b engage with grooves 53a and 53b formed on the outer periphery of the insulating plates 20a and 20b, so that the cylindrical cover member 50 is supported by the insulating plates 20a and 20b.

  As shown in FIG. 2, the casing 14 includes end plates 22 a and 22 b that are end plates, and four side plates 54 a to 54 d disposed on the side of the stacked body 12 in which the unit cells 16 are stacked, A hinge structure 56 that connects the end plates 22a and 22b and the side plates 54a to 54d, and angle members 60a to 60d that connect the adjacent end portions of the side plates 54a to 54d with bolts 58. Prepare.

  The hinge structure 56 is provided at the longitudinal ends of the first cylindrical portions 62a and 62b provided on the upper, lower, left and right sides of the end plates 22a and 22b and the side plates 54a to 54d, and the first cylindrical portions 62a and 62b. Second cylindrical portions 64a to 64d arranged alternately and coaxially, and pin members 66a and 66b having different lengths inserted integrally with the first cylindrical portions 62a and 62b and the second cylindrical portions 64a to 64d, respectively. Is provided.

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

  First, in the fuel cell stack 10, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied to the oxidant gas supply communication hole 32a of the end plate 22a, and the fuel gas supply communication hole 36a contains hydrogen. Fuel gas such as gas is supplied. Further, a coolant such as pure water or ethylene glycol is supplied to the coolant supply passage 34a. For this reason, the oxidant gas, the fuel gas, and the cooling medium are respectively supplied in the arrow A direction to the plurality of unit cells 16 overlapped in the arrow A direction.

  As shown in FIG. 3, the oxidant gas is introduced into the oxidant gas flow path 46 of the second separator 30 through the oxidant gas supply communication hole 32 a and along the cathode side electrode 42 of the electrolyte membrane / electrode structure 26. Move in the direction of arrow C. On the other hand, the fuel gas is introduced into the fuel gas flow path 44 of the first separator 28 from the fuel gas supply communication hole 36 a and moves in the direction of arrow C along the anode side electrode 40 of the electrolyte membrane / electrode structure 26.

  Therefore, in each electrolyte membrane / electrode structure 26, the oxidant gas supplied to the cathode side electrode 42 and the fuel gas supplied to the anode side electrode 40 are consumed by an electrochemical reaction in an electrode catalyst layer (not shown). And power generation is performed.

  Next, the oxidant gas supplied to and consumed by the cathode side electrode 42 is discharged to the outside from the oxidant gas discharge communication hole 32b. Similarly, the fuel gas supplied to and consumed by the anode side electrode 40 is discharged to the outside from the fuel gas discharge communication hole 36b.

  The cooling medium flows in the direction of the arrow C after being introduced into the cooling medium flow path 48 between the first and second separators 28 and 30 from the cooling medium supply communication hole 34a. The cooling medium is discharged from the cooling medium discharge communication hole 34b after the electrolyte membrane / electrode structure 26 is cooled.

  In this case, in the first embodiment, as shown in FIG. 4, a cylindrical cover member 50 is provided between the insulating plates 20 a and 20 b so as to cover the laminate 12, and the cylindrical cover member 50 is a liquid. A gas permeable membrane that is impermeable to gas and permeable to gas is provided. For this reason, in order to prevent water, dust, etc. from entering the inside of the fuel cell stack 10 from the outside, it is not necessary to accommodate the fuel cell stack 10 in, for example, a sealed container (not shown).

  Accordingly, it is possible to easily reduce the weight and size of the entire fuel cell stack 10 and improve the waterproofness and dustproofness inside the fuel cell stack 10.

  In addition, when a reaction gas, for example, fuel gas, leaks from the inside of the laminate 12, the cylindrical cover member 50 that circulates around the laminate 12 ensures a sufficient area. It becomes possible to discharge the laminate 12 to the outside. Therefore, it is possible to dilute the fuel gas outside the laminated body 12, and there is an advantage that, for example, an exhaust device or the like is not required, which is economical.

  FIG. 5 is an explanatory side view of the fuel cell stack 70 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. Similarly, in the third and fourth embodiments described below, detailed description thereof is omitted.

  The fuel cell stack 70 includes a casing 72 that houses the stacked body 12, and a cylindrical cover member 74 is supported by the insulating plates 20a and 20b. The cylindrical cover member 74 includes a gas permeable film 76 and an elastic seal member 78, and the gas permeable film 76 and the seal member 78 are integrated by adhesion, heat welding, or the like. The seal member 78 is integrally formed with bulging portions 80a and 80b that engage with the groove portions 53a and 53b of the insulating plates 20a and 20b.

  The casing 72 has end plates 22 a and 22 b as end plates, and four side plates 82 are connected by a hinge structure 84. The hinge structure 84 is provided with a panel portion 86 that protrudes toward the laminated body 12, and the panel portion 86 engages with a seal member 78 that constitutes the cylindrical cover member 74.

  The panel portion 86 has a function of fixing the cylindrical cover member 74 to the insulating plates 20a and 20b by pressing and holding the seal member 78, and also has a function of preventing the seal member 78 from being lifted and ensuring a sealing property. Also have.

  Thereby, in 2nd Embodiment, the effect similar to said 1st Embodiment is acquired by using the cylindrical cover member 74. FIG. Moreover, by surrounding the outer periphery of the cylindrical cover member 74 via the casing 72, damage to the thin gas permeable membrane 76 can be prevented.

  In the first and second embodiments, for example, a cylindrical cover member 90 shown in FIG. 6 may be used instead of the cylindrical cover members 50 and 74. The cylindrical cover member 90 is provided with a water absorption layer 94 inside the gas permeable membrane 92.

  Therefore, the dew condensation water generated on the surfaces of the first separator 28 and the second separator 30 constituting each unit cell 16 can be quickly absorbed and diffused by the water absorption layer 94. For this reason, there are advantages that dew condensation water is prevented from staying in the first separator 28 and the second separator 30 and that evaporation to the outside is promoted through the gas permeable membrane 92.

  FIG. 7 is a schematic perspective view of a fuel cell stack 100 according to the third embodiment of the present invention, and FIG. 8 is a partially omitted perspective view of the fuel cell stack 100.

  The fuel cell stack 100 includes a plurality of connectors 102 for detecting a cell voltage for each unit cell 16 or for each of the plurality of unit cells 16, and the connector 102 is connected to a cell voltage terminal (not shown). . The harness 104 connected to each connector 102 is connected to a voltage measuring device (not shown).

  As shown in FIGS. 8 and 9, a cylindrical cover member 106 is provided so as to cover the laminated body 12. The cylindrical cover member 106 is configured by integrating a gas permeable film 76 and a seal member 78, and a seal portion 108 is provided corresponding to the connector 102. The opening 110 of the seal portion 108 is covered with a connector cover 112, and the connector cover 112 and the seal portion 108 constitute a connection structure 114 that ensures waterproofness.

  The cylindrical cover member 106 may be configured in advance in a cylindrical shape, or may be formed in a cylindrical shape by providing a waterproof connection structure 114 at both ends of the sheet and joining the both ends to each other. . The cylindrical cover member 106 may be divided into two parts. This is because assemblability and maintainability are improved.

  FIG. 10 is an explanatory side view of the fuel cell stack 120 according to the fourth embodiment of the present invention.

  In the fuel cell stack 120, an end plate 122a and an intermediate plate 124 are disposed outside the insulating plates 20a and 20b, and a plurality of disc springs 126 are interposed in the intermediate plate 124, and the end plate 122b. Is disposed. A fastening force is applied between the end plates 122a and 122b in the stacking direction (arrow A direction) by a fastening member, for example, a plurality of fastening bolts 128 and nuts 130. In addition, as a fastening member, it replaces with the fastening bolt 128 and a band member, a wire member, etc. can be used.

  A cylindrical cover member 132 is attached to the insulating plates 20a and 20b so as to cover the laminate 12. For example, the cylindrical cover member 132 is configured in the same manner as the cylindrical cover member 50 used in the first embodiment.

  The cylindrical cover member 132 is preferably configured to be stretchable in the direction of the arrow A in accordance with the dimensional variation between the insulating plates 20a and 20b, and is set to a fiber structure having elasticity in the direction of the arrow A.

  Thereby, in the fourth embodiment, since the tightening bolt 128 and the nut 130 are used instead of the casing structure, the distance between the insulating plates 20a and 20b varies. In that case, the fluctuation | variation between the insulation plates 20a and 20b can be easily tracked by the elasticity of the cylindrical cover member 132 itself. Therefore, it is possible to prevent water and dust from entering the laminated body 12 from the outside, and to quickly discharge the fuel gas to the outside. Similar effects can be obtained.

1 is a schematic perspective view of a fuel cell stack according to a first embodiment of the present invention. It is a partially exploded perspective view of the fuel cell stack. It is a disassembled perspective explanatory drawing of the unit cell which comprises a fuel cell stack. It is side surface explanatory drawing of the said fuel cell stack. It is side surface explanatory drawing of the fuel cell stack which concerns on the 2nd Embodiment of this invention. It is side surface explanatory drawing of the fuel cell stack with which the different cylindrical cover member was mounted | worn. FIG. 6 is a schematic perspective view of a fuel cell stack according to a third embodiment of the present invention. FIG. 3 is a partially omitted perspective view of the fuel cell stack. It is side surface explanatory drawing of the said fuel cell stack. It is side surface explanatory drawing of the fuel cell stack which concerns on the 4th Embodiment of this invention. 10 is an explanatory diagram of a fuel cell case of Patent Document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 70, 100, 120 ... Fuel cell stack 12 ... Laminated body 14, 72 ... Casing 16 ... Unit cell 20a, 20b ... Insulating plate 22a, 22b, 122a, 122b ... End plate 26 ... Electrolyte membrane and electrode structure 28, 30 ... Separator 32a ... Oxidant gas supply communication hole 32b ... Oxidant gas discharge communication hole 34a ... Cooling medium supply communication hole 34b ... Cooling medium discharge communication hole 36a ... Fuel gas supply communication hole 36b ... Fuel gas discharge communication hole 38 ... Solid Polymer electrolyte membrane 40 ... Anode side electrode 42 ... Cathode side electrode 44 ... Fuel gas channel 46 ... Oxidant gas channel 48 ... Cooling medium channels 50, 74, 90, 106, 132 ... Cylinder cover members 52a, 52b ... Thick parts 53a and 53b ... Groove parts 76 and 92 ... Gas permeable membrane 78 ... Seal members 80a and 80b ... Swelling part 86 ... Panel Part 94 ... water-absorbing layer 102 ... connector 108 ... seal unit 112 ... connector cover 124 ... intermediate plate 126 ... disc spring

Claims (5)

A laminate in which a separator and an electrolyte / electrode structure in which a pair of electrodes are provided on both sides of an electrolyte are stacked is a fuel cell stack disposed between insulating members,
While including a cylindrical cover member that covers the laminate and circulates at least in a range sandwiched between the insulating members,
The fuel cell stack, wherein the cylindrical cover member is provided with a gas permeable membrane that is impermeable to liquid and permeable to gas.   2. The fuel cell stack according to claim 1, wherein the cylindrical cover member includes an elastic seal member at a portion engaged with the insulating member. The fuel cell stack according to claim 1 or 2, wherein the insulating member is sandwiched between a pair of end plates,
The fuel cell stack, wherein the laminate and the cylindrical cover member are surrounded by a casing having the pair of end plates as end plates. The fuel cell stack according to claim 1 or 2, wherein the insulating member is sandwiched between a pair of end plates,
The pair of end plates are fastened and held by a fastening member so as to be expandable and contractable in the stacking direction. The fuel cell stack according to any one of claims 1 to 4, wherein the cylindrical cover member is made of an anisotropic material,
A fuel cell stack having maximum elasticity along the stacking direction.

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