JP5302758B2 - Fuel cell stack - Google Patents

Description

  The present invention relates to a fuel cell stack in which a plurality of unit cells each having an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked.

  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. This type of fuel cell is normally used as a fuel cell stack by stacking a predetermined number of unit cells.

  The 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 for in-vehicle use, for example. In this type of fuel cell stack, it is necessary to detect whether each unit cell has a desired power generation performance. For this reason, generally, the operation | work which detects the cell voltage for every unit cell at the time of electric power generation by connecting the cell voltage terminal provided in the separator to the voltage detection apparatus (cell voltage monitor) is performed.

  For example, as shown in FIG. 13, a fuel cell stack disclosed in Patent Document 1 includes a plurality of separators 1, 2, and 3 stacked, and terminal plates 4a, 4b, insulating plates at both ends in the stacking direction. 5a, 5b and pressure plates 6a, 6b are arranged. The separator 1 is provided with a voltage measuring terminal 7a, while the separator 2 is provided with a voltage measuring terminal 7b.

  The voltage measuring terminal 7 b of the separator 2 is provided at the same end as the voltage measuring terminal 7 a of the separator 1 and shifted downward. That is, when assembled in the fuel cell stack, the voltage measuring terminals 7a and 7b adjacent to each other do not come into contact with each other and are separated from each other vertically. Furthermore, one end of a voltage measurement cord 8 is connected to the voltage measurement terminals 7a and 7b, and the other end of the voltage measurement cord 8 is connected to a one-touch connector 9.

JP 2000-223141 A

  In the fuel cell stack described above, it is desired to reduce the thickness of the separators 1, 2 and 3, and the gap between the voltage measuring terminals 7a and 7b tends to be considerably narrow. Therefore, it is necessary to arrange the voltage measuring terminals 7a and 7b so as to be offset from each other, and the separators 1 and 2 have different configurations. Thereby, the kind of separator increases and there exists a problem that it is not economical.

  The present invention solves this type of problem, and a current extraction terminal can be provided at the same position of the separator, which prevents the number of types of the separator from increasing and is connected to the current extraction terminal. An object of the present invention is to provide a fuel cell stack in which connectors can be arranged as close as possible.

  The present invention relates to a fuel cell stack in which a plurality of unit cells each having an electrolyte membrane / electrode structure provided with a pair of electrodes on both sides of an electrolyte membrane and a separator are stacked.

  The separator is provided with a current extraction terminal for extracting an electric current to the outside, and a plurality of connectors can be connected to the single current extraction terminal while being shifted from each other in a direction intersecting the stacking direction of the unit cells. A plurality of connecting portions are provided.

  In addition, it is preferable that the current extraction terminal is formed to protrude outward from the side portion of the separator, and the current extraction terminal is provided with a plurality of connection portions in the width direction along the side portion.

  Furthermore, the current extraction terminal is preferably formed to protrude outward from the side portion of the separator, and the current extraction terminal is preferably provided with a plurality of connection portions in a length direction along the protruding direction.

  Furthermore, in this fuel cell stack, it is preferable that the connectors are connected to the current extraction terminals adjacent to each other in a staggered manner along the stacking direction.

  According to the present invention, since a single current extraction terminal is provided with a plurality of connecting portions to which a plurality of connectors can be connected, the adjacent connectors are positioned relative to each other in a direction intersecting the stacking direction of the unit cells. Can be arranged in a staggered manner. Therefore, it is possible to secure a good connector arrangement space, and the connectors can be arranged as close as possible.

  In addition, it is only necessary to provide a current extraction terminal at the same position of the separator, and it is possible to effectively prevent an increase in the number of types of the separator and to economically configure the fuel cell stack.

1 is a perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. It is a principal part disassembled perspective explanatory drawing of the fuel cell which comprises the said fuel cell stack. It is explanatory drawing of the connection state of the voltage measurement terminal and connector which comprise the said fuel cell stack. It is side surface explanatory drawing of the said voltage measurement terminal and the said connector. FIG. 5 is a perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention. It is explanatory drawing of the connection state of the voltage measurement terminal and connector which comprise the said fuel cell stack. It is side surface explanatory drawing of the said voltage measurement terminal and the said connector. FIG. 6 is a perspective explanatory view of a fuel cell stack according to a third embodiment of the present invention. It is explanatory drawing of the fuel cell stack which concerns on the 4th Embodiment of this invention. It is explanatory drawing of the fuel cell module and bypass circuit which comprise the said fuel cell stack. It is explanatory drawing of the fuel cell stack which concerns on the 5th Embodiment of this invention. It is explanatory drawing of the fuel cell module and discharge circuit which comprise the said fuel cell stack. 2 is an explanatory diagram of a fuel cell stack of Patent Document 1. FIG.

  As shown in FIG. 1, in the fuel cell stack 10 according to the first embodiment of the present invention, a plurality of fuel cells (unit cells) 12 are stacked in the direction of arrow A (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.

  A tightening load is applied to the first end plate 18 a and the second end plate 18 b via the plurality of tie rods 19 in the stacking direction. Instead of the tie rod 19, a box-shaped casing or the like can be used.

  As shown in FIG. 2, the fuel cell 12 includes an electrolyte membrane / electrode structure 20 sandwiched between first and second separators 22 and 24. The first and second separators 22 and 24 are made of, for example, a metal separator such as a steel plate, a stainless steel plate, an aluminum plate, or a plated steel plate, or a carbon separator.

  An oxidation for supplying an oxidant gas, for example, an oxygen-containing gas, to the upper edge of the fuel cell 12 in the direction of arrow C (the gravitational direction in FIG. 2) communicates with each other in the direction of arrow A, which is the stacking direction. 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 the arrow B direction (horizontal direction).

  The lower end edge of the fuel cell 12 in the direction of arrow C 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 outlet for discharging the oxidant gas. The communication holes 26b are arranged in the direction of arrow C.

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

  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 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 20 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 45 that sandwich the solid polymer electrolyte membrane 42. With.

  The cathode side electrode 44 and the anode side electrode 45 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.

  A concave portion 46 is formed on one side of the short side direction (arrow B direction) of the fuel cell 12. For example, the second separator 24 protrudes into the concave portion 46 and has a voltage measurement terminal (current extraction terminal). 48 is provided. A plurality of, for example, two connectors 50a and 50b to which two connectors 56 described later can be connected simultaneously are set up and down on the voltage measuring terminal 48 (see FIGS. 2 and 3).

  As shown in FIG. 1, on the upper side of the first end plate 18a, an oxidant gas inlet manifold 52a communicating with the oxidant gas inlet communication hole 26a and a fuel gas inlet manifold 54a communicating with the fuel gas inlet communication hole 28a are provided. And are provided. An oxidant gas outlet manifold 52b communicating with the oxidant gas outlet communication hole 26b and a fuel gas outlet manifold 54b communicating with the fuel gas outlet communication hole 28b are provided on the lower side of the first end plate 18a.

  Although not shown, the second end plate 18b includes a cooling medium inlet manifold that extends in the direction of arrow C and communicates with the cooling medium inlet communication hole 30a, and a cooling medium outlet manifold that communicates with the cooling medium outlet communication hole 30b. Is provided.

  A connector 56 is connected to the voltage measuring terminal 48 of the second separator 24 constituting each fuel cell 12 while shifting the position in a direction intersecting the stacking direction of the fuel cells 12. The connector 56 is connected to a voltage measuring device (ECU) 60 via a cable 58.

  As shown in FIGS. 3 and 4, the connector 56 has connection terminal portions 62 that are alternately connected to the connection portions 50 a and 50 b of the voltage measurement terminal 48. The voltage measuring terminals 48 adjacent to each other are alternately connected to the connecting portions 50a and 50b, so that the connectors 56 are arranged in a staggered manner in the direction of arrow A.

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

  First, as shown in FIG. 1, an oxidant gas such as an oxygen-containing gas is supplied from an oxidant gas inlet manifold 52a of the first end plate 18a to the oxidant gas inlet communication hole 26a, and a fuel gas inlet manifold. Fuel gas such as hydrogen-containing gas is supplied from 54a to the fuel gas inlet communication hole 28a. On the other hand, a cooling medium such as pure water or ethylene glycol is supplied from the cooling medium inlet manifold of the second end plate 18b to the cooling medium inlet communication hole 30a.

  For this reason, as shown in FIG. 2, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas inlet communication hole 26 a. The oxidant gas is supplied to the cathode side electrode 44 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 45 constituting the electrolyte membrane / electrode structure 20 while moving in the direction of arrow C.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 44 and the fuel gas supplied to the anode side electrode 45 are consumed by an electrochemical reaction in the electrode catalyst layer to generate power. Is done.

  Next, the oxidant gas supplied and consumed to the cathode side electrode 44 is discharged in the direction of arrow A along the oxidant gas outlet communication hole 26b, and is discharged to the oxidant gas outlet manifold 52b of the first end plate 18a. (See FIG. 1).

  On the other hand, the fuel gas supplied to and consumed by the anode side electrode 45 is discharged in the direction of arrow A along the fuel gas outlet communication hole 28b, and is discharged to the fuel gas outlet manifold 54b of the first end plate 18a.

  The cooling medium supplied to the 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 C. After cooling the electrolyte membrane / electrode structure 20, the cooling medium is discharged from the cooling medium outlet communication hole 30b to the second end plate 18b.

  In this case, in the first embodiment, the single voltage measurement terminal 48 includes a plurality of, for example, two connection portions 50a and 50b that can connect two connectors 56 in the width direction (arrow C direction). Yes. For this reason, the connectors 56 adjacent to each other can be arranged in a staggered manner, with the positions shifted from each other in the direction (arrow C direction) intersecting the stacking direction of the fuel cells 12 (see FIG. 3).

  Therefore, it is possible to secure a good space for the connectors 56. In particular, even when the fuel cell 12 is configured to be thin, the connectors 56 are arranged as close as possible. Can do.

  Moreover, it is only necessary to provide voltage measuring terminals 48 having the same shape at the same position of the second separator 24. Thereby, the second separators 24 of the fuel cells 12 adjacent to each other are electrically connected to each other via the connector 56 connected to the connection portion 50a or 50b of the voltage measurement terminal 48. For this reason, it is possible to effectively prevent an increase in the type of the second separator 24 and to achieve an economical configuration of the fuel cell stack 10.

  FIG. 5 is a perspective explanatory view of a fuel cell stack 80 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 embodiment described below, detailed description thereof is omitted.

  The fuel cell stack 80 is provided with a voltage measurement terminal 82, and the voltage measurement terminal 82 is provided with a plurality of, for example, two connection portions 84a and 84b in the length direction along the protruding direction (arrow B direction). Connectors 56 are alternately connected to connecting portions 84a and 84b at voltage measuring terminals 82 adjacent to each other, and the connectors 56 are connected to each other in a staggered manner along the stacking direction (FIGS. 6 and 7). reference).

  Therefore, in the second embodiment, two connection portions 84 a and 84 b that can connect the two connectors 56 to the single voltage measurement terminal 82 are provided. As a result, the same effects as those of the first embodiment described above can be obtained, for example, it is possible to economically configure the fuel cell stack 80 without increasing the types of separators.

  FIG. 8 is a perspective explanatory view of a fuel cell stack 90 according to the third embodiment of the present invention.

  The fuel cell stack 90 stacks a plurality of fuel cells 12 along the direction of gravity, and a first end plate 18a and a second end plate 18b are disposed at both ends in the stacking direction. The second end plate 18b is disposed at the upper end, and although not shown, the inlets and outlets for the fuel gas, the oxidant gas, and the cooling medium are concentrated on the first end plate 18a side.

  The first end plate 18 a and the second end plate 18 b are fixed to a plurality of metal connecting members 92 via screws 94. A voltage measuring terminal 48 (or 82) is formed on one short side (or long side) of each fuel cell 12, and connectors 56 are staggered in the vertical direction on the voltage measuring terminal 48. Arranged.

  As a result, in the third embodiment, the fuel cell 12 can be easily thinned, and the increase in the number of types of separators can be effectively prevented, and the fuel cell stack 90 can be configured in a small and economical manner. For example, the same effects as those of the first and second embodiments can be obtained.

  In the first to third embodiments, the voltage measurement terminals 48 and 82 are used as the current extraction terminals, but the present invention is not limited to this.

  The fuel cell stack 100 according to the fourth embodiment of the present invention shown in FIG. 9 is a fuel cell in which a plurality of fuel cells 12 are stacked in the direction of arrow A and a predetermined number of the fuel cells 12 are connected in series. The module 102 is configured. The fuel cell module 102 may be a single fuel cell 12.

  Current extraction terminals 104a and 104b are provided at both ends in the stacking direction of each fuel cell module 102, and a connector (not shown) of a bypass circuit 106 is connected to the current extraction terminals 104a and 104b. As in the first to third embodiments, the bypass circuits 106 are connected to each other with their positions shifted in a direction intersecting the stacking direction of the fuel cells 12.

  The bypass circuit 106 is provided with a diode 108. As shown in FIG. 10, the diode 108 has an anode side connected to the anode side electrode 45 and a cathode side connected to the cathode side electrode 44. The diode 108 is set to be in a reverse bias state when the fuel cell module 102 is normal, and to be in a forward bias state when an abnormality occurs in the fuel cell module 102.

  In the fourth embodiment configured as described above, when a failure occurs in any of the fuel cells 12, the diode 108 connected in parallel to the fuel cell module 102 including the fuel cell 12 is in a forward bias state, A current flows through the diode 108 (see FIG. 10).

  A fuel cell stack 110 according to the fifth embodiment of the present invention shown in FIG. 11 is a fuel cell in which a plurality of fuel cells 12 are stacked in the direction of arrow A, and a predetermined number of the fuel cells 12 are connected in series. The module 112 is configured. The fuel cell module 112 may be a single fuel cell 12.

  Current extraction terminals 114a and 114b are provided at both ends in the stacking direction of each fuel cell module 112, and a connector (not shown) of a discharge circuit 116 is connected to the current extraction terminals 114a and 114b. As in the first to fourth embodiments, the discharge circuits 116 are connected to each other while being displaced from each other in the direction intersecting the stacking direction of the fuel cells 12.

  The discharge circuit 116 is provided with a diode 118. As shown in FIG. 12, the diode 118 has an anode side connected to the cathode side electrode and a cathode side connected to the anode side electrode 45.

  In the fifth embodiment configured as described above, a diode 118 is provided in order to consume gas (particularly fuel gas) remaining in the fuel cell 12 when the fuel cell stack 110 is stopped. Therefore, when the operation is stopped, a current flows through the diode 118 as shown by an arrow in each discharge circuit 116 as shown in FIG. As a result, the fuel cell module 112 is discharged, and the gas remaining in the fuel cell module 112 is consumed.

10, 80, 90, 100, 110 ... Fuel cell stack 12 ... Fuel cells 18a, 18b ... End plate 20 ... Electrolyte membrane / 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 channel 34 ... Fuel gas channel 36 ... Cooling medium channel 42 ... Solid polymer electrolyte membrane 44 ... Cathode side electrode 45 ... Anode side electrode 48, 82 ... Voltage measurement terminals 50a, 50b, 84a, 84b ... Connection part 56 ... Connector 58 ... Cable 60 ... Voltage measurement device 62 ... Connection terminal part 102 112 ... Fuel cell modules 104a, 104b, 114a, 114b ... Current extraction terminal 106 ... Bypass circuit 1 8,118 ... diode 116 ... discharge circuit

Claims (4)

A fuel cell stack in which a plurality of unit cells having an electrolyte membrane / electrode structure and a separator provided with a pair of electrodes on both sides of the electrolyte membrane are stacked,
The separator is provided with a current extraction terminal for extracting current to the outside,
A fuel cell stack, wherein a single current extraction terminal is provided with a plurality of connection portions to which a plurality of connectors can be connected with their positions shifted in a direction crossing the stacking direction of the unit cells. The fuel cell stack according to claim 1, wherein the current extraction terminal is formed to protrude outward from a side portion of the separator,
The fuel cell stack, wherein the current extraction terminal is provided with a plurality of connection portions in a width direction along the side portion. The fuel cell stack according to claim 1, wherein the current extraction terminal is formed to protrude outward from a side portion of the separator,
The fuel cell stack, wherein the current extraction terminal is provided with a plurality of the connection portions in a length direction along the protruding direction.   The fuel cell stack according to any one of claims 1 to 3, wherein the connectors are connected to the current extraction terminals adjacent to each other in a staggered manner along the stacking direction. Fuel cell stack.

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