JP2011065869A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell stack having a simple structure, wherein a resin manifold can be reliably fractured at a desired portion by an external load and a power extraction terminal can be prevented from being covered by water as much as possible. <P>SOLUTION: A first end plate 18a constituting a fuel cell stack 10 includes a piping connection structure 50. The piping connection structure 50 includes a supply-side resin manifold 52a communicating with a coolant supply communicating hole 30a. In the supply side resin manifold 52a, a supply-side piping connection part 56a to which supply-side external piping 54a is connected is formed. The supply-side piping connection part 56a is constituted such that an axis thereof is inclined downward. A fracturing part 58a preferentially fractured by an external load is provided at a position below a terminal 46a projecting from the first end plate 18a to the outside between the supply-side resin manifold 52a and the supply-side piping connection part 56a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel cell stack in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and end plates are disposed at both ends in the stacking direction.

  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 provided by a pair of separators. The unit cell is sandwiched. This type of fuel cell is usually used as an in-vehicle fuel cell stack, for example, by stacking a predetermined number of unit cells.

  In the above fuel cell, a fuel gas flow channel for flowing fuel gas is provided in the plane of one separator so as to face the anode side electrode, and the cathode side electrode is opposed in the plane of the other separator. An oxidant gas flow path for flowing an oxidant gas is provided. Further, between the separators, a cooling medium flow path for flowing the cooling medium is provided along the surface direction of the separator.

  Further, in this type of fuel cell, a fuel gas supply communication hole and a fuel gas discharge communication hole for flowing fuel gas through the unit cell in the stacking direction, and an oxidant gas supply communication hole for flowing oxidant gas In many cases, a so-called internal manifold type fuel cell is provided, which is internally provided with an oxidant gas discharge communication hole, a cooling medium supply communication hole for flowing a cooling medium, and a cooling medium discharge communication hole.

  As a technique related to the internal manifold type fuel cell, for example, a fuel cell of Patent Document 1 is known. In Patent Document 1, as shown in FIG. 7, a laminated body 1 is provided. The laminated body 1 includes an electrolyte membrane, a gas diffusion electrode that sandwiches the electrolyte membrane, and the gas diffusion electrode together with a seal member 2. A plurality of collector electrodes 3 to be sandwiched are stacked. A plurality of through holes penetrating in the stacking direction are formed in the collector electrode 3, and a fuel supply / discharge passage in the stacking direction is formed in the stack 1 by the through holes.

  End plates 4 are installed at both lamination ends of the laminate 1, and four side surfaces along the lamination direction of the laminate 1 are covered with a coating layer 5 formed of rubber. The end plate 4 is formed in a square plate shape with resin, and circular through holes 6 and 7 are formed in the center near the edges of two adjacent sides among the four sides. The through hole 6 of one end plate 4 communicates with an oxidizing gas supply / discharge flow path formed in the laminate, and the through hole 7 communicates with a fuel gas supply / discharge flow path.

  In this fuel cell, even if a load acts on the laminated body 1 and a crack or the like occurs in the formation portion of the fuel supply / discharge passage, the coating layer 5 blocks the inside of the laminated body 1 from the outside. The fuel can be prevented from leaking from the supply / discharge flow path.

JP-A-8-162143

  By the way, in the above Patent Document 1, there are cases where a fuel gas resin manifold and an oxidant gas resin manifold are usually provided on the end plate 4 in order to connect external piping to the through holes 6 and 7. . Therefore, for example, when a load from the outside is applied to the fuel cell, an excessive load acts on the external piping, stress is generated in the connected resin manifold, and the resin manifold is easily damaged.

  At that time, particularly when the resin manifold of the cooling medium is damaged and the cooling medium is led out to the outside, a terminal terminal for power extraction (not shown) exposed to the outside from the end plate 4 gets wet, and the liquid junction May be caused.

  The present invention solves this type of problem, and with a simple configuration, the resin manifold can be surely broken at a desired site by an external load, and the power extraction terminal terminal is exposed to water. An object of the present invention is to provide a fuel cell stack that can be prevented as much as possible.

  The present invention relates to a fuel cell stack in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and end plates are disposed at both ends in the stacking direction.

  This fuel cell stack includes a pipe connection structure for connecting a fluid communication hole for circulating a fluid as a cooling medium or a reaction gas in the stacking direction of the electrolyte / electrode structure and the separator to an external pipe.

  The pipe connection structure includes a resin manifold that is provided on at least one end plate and communicates with a fluid communication hole, and a pipe connection portion that is formed in the resin manifold and is connected to an external pipe. A breakage site that is preferentially broken by a load from the outside is provided below the power connection terminal terminal that protrudes outward from the end plate.

  Moreover, it is preferable that a fracture | rupture site | part is comprised by shifting the axis line of the piping connection part integrally formed in the said bulging part with respect to the axis line of the bulging part provided in a resin manifold.

  Furthermore, it is preferable that a fracture | rupture site | part is comprised by providing a notch or a recessed part in the outer periphery of a piping connection part.

  Furthermore, it is preferable that the pipe connection portion has the axis inclined downward.

  According to the present invention, when an external load is applied to the pipe connection structure, an eccentric fracture site provided between the resin manifold and the pipe connection portion is caused by an excessive load applied to the external pipe. Breaks preferentially due to concentration of Here, the breaking portion is located below the power extraction terminal terminal protruding outward from the end plate, and the fluid led out from the breaking portion is surely below the power extraction terminal terminal. Can flow.

  For this reason, it is possible to reliably break the resin manifold at a desired cutting site by a load from the outside with a simple configuration, and to prevent the power extraction terminal terminal from being wetted as much as possible. it can.

1 is a schematic perspective explanatory view of a fuel cell stack according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the fuel cell stack taken along line II-II in FIG. 1. 2 is an exploded perspective view of a fuel cell constituting the fuel cell stack. FIG. It is front explanatory drawing of the piping connection structure which comprises the said fuel cell stack. FIG. 5 is a schematic perspective explanatory view of a fuel cell stack according to a second embodiment of the present invention. It is a partial side view explanatory drawing of the piping connection structure which comprises the said fuel cell stack. 2 is a perspective explanatory view of a fuel cell disclosed in Patent Document 1. FIG.

  As shown in FIG. 1, a fuel cell stack 10 according to a first embodiment of the present invention includes a fuel cell 12, and a plurality of the fuel cells 12 are stacked on each other along a horizontal direction (arrow A direction). Composed. The fuel cell stack 10 is used for in-vehicle use, for example.

  As shown in FIGS. 1 and 2, 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 other end in the stacking direction is The second terminal plate 14b, the second insulating plate 16b, and the second end plate 18b are stacked.

  The first end plate 18 a and the second end plate 18 b configured in a rectangular shape are integrally clamped and held by a plurality of tie rods 19 extending in the arrow A direction. Note that the fuel cell stack 10 may be integrally held by a box-shaped casing (not shown) including the first end plate 18a and the second end plate 18b as end plates.

  As shown in FIG. 3, in the fuel cell 12, the electrolyte membrane / electrode structure 20 is sandwiched between the first and second separators 22 and 24. The first and second separators 22 and 24 are made of carbon separators, for example, but may be made of metal separators such as steel plates, stainless steel plates, aluminum plates, or plated steel plates. The first and second separators 22 and 24 constitute a rectangular separator, and the long side direction extends, for example, in the vertical direction (direction of arrow C).

  Oxidation for supplying an oxidant gas, for example, an oxygen-containing gas, is communicated with the upper edge of the fuel cell 12 in the direction of arrow C (the gravity direction in FIG. 3) in the direction of arrow A, which is the stacking direction. The agent gas supply communication holes 26a and the fuel gas supply communication holes 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, and the oxidant gas discharge communication hole 26b for discharging the oxidant gas, and the fuel gas discharge for discharging the fuel gas. The communication holes 28b are arranged in the arrow B direction.

  A cooling medium supply communication hole 30a for supplying a cooling medium and a cooling medium discharge communication hole 30b for discharging the cooling medium are provided at both ends of the fuel cell 12 in the arrow B direction. The cooling medium supply communication hole 30 a and the cooling medium discharge communication hole 30 b are configured by rectangular openings that are long in the long side direction (arrow C direction) of the first and second separators 22 and 24.

  An oxidant gas flow path 32 communicating with the oxidant gas supply communication hole 26a and the oxidant gas discharge 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 supply communication hole 28a and the fuel gas discharge 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 supply communication hole 30a and the cooling medium discharge communication hole 30b between the surface 22b of the first separator 22 and the surface 24b of the second separator 24 constituting the fuel cells 12 adjacent to each other. A flow path 36 is provided.

  A first seal member 38 a is provided on the surfaces 22 a and 22 b of the first separator 22, and a second seal member 38 b is provided on the surfaces 24 a and 24 b of the second separator 24.

  The electrolyte membrane / electrode structure 20 includes, for example, a solid polymer electrolyte membrane 40 in which a perfluorosulfonic acid thin film is impregnated with water, and a cathode side electrode 42 and an anode side electrode 44 that sandwich the solid polymer electrolyte membrane 40. With.

  The cathode side electrode 42 and the anode side electrode 44 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 40.

  As shown in FIGS. 1 and 2, a power extraction terminal terminal 46a is integrally provided on the center upper side of the first terminal plate 14a so as to protrude outward in the stacking direction (on the first end plate 18a side). The terminal terminal 46a is exposed to the outside through the first insulating plate 16a and the first end plate 18a in a state of being fitted to the insulating cylinder 48a.

  Similarly, a power extraction terminal terminal 46b is integrally provided on the upper center side of the second terminal plate 14b. The terminal terminal 46b is exposed to the outside through the second insulating plate 16b and the second end plate 18b in a state of being fitted to the insulating cylinder 48a.

  A pipe connection structure 50 is provided on the outer surface side of the first end plate 18a. The pipe connection structure 50 includes a supply-side resin manifold 52a that is provided in the first end plate 18a and communicates with the cooling medium supply communication hole 30a, and a discharge-side resin manifold 52b that communicates with the cooling medium discharge communication hole 30b. The supply side resin manifold 52a and the discharge side resin manifold 52b have a vertically long shape along the opposing long sides.

  The supply side resin manifold 52a is provided with a supply side pipe connection portion 56a for connecting the supply side external pipe 54a, and the discharge side resin manifold 52b is provided with a discharge side for connecting the discharge side external pipe 54b. A pipe connection portion 56b is formed. The supply side pipe connection part 56a and the discharge side pipe connection part 56b have a cylindrical shape and are configured such that each axis is inclined downward.

  Between the supply-side resin manifold 52a and the supply-side pipe connecting portion 56a, a breakage portion 58a that breaks preferentially by an external load is located below the terminal terminal 46a that protrudes outward from the first end plate 18a. They are provided separated by a distance L (see FIG. 2).

  As shown in FIGS. 2 and 4, the fractured portion 58a is formed on the supply side pipe connecting portion 56a integrally formed with the bulging portion 60a with respect to the axis O1 of the bulging portion 60a provided on the supply side resin manifold 52a. Is shifted by a distance H. The fracture portion 58a is a portion where the thickness changes stepwise with respect to the bulging portion 60a, and a portion where the bulging portion 60a and the supply side pipe connection portion 56a are connected eccentrically, that is, stress is concentrated. It is a part that is easy to do.

  Between the discharge-side resin manifold 52b and the discharge-side pipe connection portion 56b, a breakage portion 58b that is preferentially broken by an external load is provided below the terminal terminal 46b. As shown in FIG. 4, the fracture site 58b has an axis O2 of the discharge side pipe connection part 56b integrally formed with the bulge part 60b with respect to the axis line O1 of the bulge part 60b provided in the discharge side resin manifold 52b. Is shifted by a distance H.

  Although not shown, the second end plate 18b is provided with a resin manifold in communication with the oxidant gas supply communication hole 26a, the fuel gas supply communication hole 28a, the oxidant gas discharge communication hole 26b, and the fuel gas discharge communication hole 28b. It is done.

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

  First, an oxidant gas such as an oxygen-containing gas is supplied from the resin manifold (not shown) of the second end plate 18b to the oxidant gas supply communication hole 26a, and the fuel gas supply communication is made from the resin manifold (not shown). A fuel gas such as a hydrogen-containing gas is supplied to the hole 28a.

  Furthermore, as shown in FIG. 1, on the first end plate 18a side, a cooling medium such as pure water, ethylene glycol, or oil is supplied from the supply-side external pipe 54a to the supply-side resin manifold 52a through the supply-side pipe connection portion 56a. Supplied. This cooling medium is supplied from the supply-side resin manifold 52a to the cooling medium supply communication hole 30a.

  Therefore, the oxidant gas is introduced into the oxidant gas flow path 32 of the first separator 22 from the oxidant gas supply communication hole 26a as shown in FIG. The oxidant gas moves in the direction of arrow C (the direction of gravity) along the oxidant gas flow path 32 and is supplied to the cathode side electrode 42 of the electrolyte membrane / electrode structure 20.

  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 supply communication hole 28a. The fuel gas moves along the fuel gas flow path 34 in the direction of gravity (arrow C direction) and is supplied to the anode side electrode 44 of the electrolyte membrane / electrode structure 20.

  Therefore, in the electrolyte membrane / electrode structure 20, the oxidant gas supplied to the cathode side electrode 42 and the fuel gas supplied to the anode side electrode 44 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 electrode 42 of the electrolyte membrane / electrode structure 20 is discharged in the direction of arrow A along the oxidant gas discharge communication hole 26b. The fuel gas consumed by being supplied to the anode electrode 44 of the electrolyte membrane / electrode structure 20 is discharged in the direction of arrow A along the fuel gas discharge communication hole 28b.

  On the other hand, the cooling medium supplied to the cooling medium supply communication hole 30 a is introduced into the cooling medium flow path 36 formed between the first separator 22 and the second separator 24. The cooling medium moves in the direction of arrow B to cool the electrolyte membrane / electrode structure 20, and is then discharged to the cooling medium discharge communication hole 30b. As shown in FIG. 1, the cooling medium is introduced into a discharge-side resin manifold 52b provided in the first end plate 18a, and is discharged to the outside from the discharge-side pipe connection portion 56b through the discharge-side external pipe 54b.

  In this case, in the first embodiment, the pipe connection structure 50 is provided in the first end plate 18a and is formed in the supply side resin manifold 52a communicating with the cooling medium supply communication hole 30a and the supply side resin manifold 52a. And a supply side pipe connection part 56a to which the supply side external pipe 54a is connected.

  And between the supply side resin manifold 52a and the supply side piping connection part 56a, the fracture | rupture site | part 58a fracture | ruptured preferentially by the load from the outside is provided and located below the terminal terminal 46a.

  Specifically, as shown in FIGS. 2 and 4, the fractured portion 58a is supplied integrally with the bulging portion 60a with respect to the axis O1 of the bulging portion 60a provided in the supply-side resin manifold 52a. It is configured by shifting the axis O2 of the side pipe connecting portion 56a by a distance H. The fracture portion 58a is a portion where the bulging portion 60a and the supply side pipe connection portion 56a are eccentrically connected, that is, a portion where stress is easily concentrated.

  For this reason, when an external load is applied to the pipe connection structure 50, stress is generated in the supply-side resin manifold 52a due to an excessive load applied to the supply-side external pipe 54a. In that case, the eccentric fracture | rupture site | part 58a provided between the supply side resin manifold 52a and the supply side piping connection part 56a can be preferentially fracture | ruptured when stress concentrates.

  Here, the fracture | rupture site | part 58a is spaced apart by the distance L below the terminal terminal 46a which protrudes outside from the 1st end plate 18a (refer FIG. 2). Therefore, the cooling medium (fluid) derived from the fractured portion 58a flows below the terminal terminal 46a, and the terminal terminal 46a is prevented from getting wet.

  In addition, the supply side pipe connecting portion 56a is configured such that the axis is inclined downward from the horizontal posture. Thereby, when a load is applied in the horizontal direction, stress can be concentrated on the fractured portion 58a, and the fractured portion 58a can be reliably broken. For this reason, it is possible to satisfactorily prevent the supply-side resin manifold 52a itself from being damaged. In addition, there is an advantage that the exclusive space in the horizontal direction can be effectively reduced compared to the configuration in which the supply side pipe connection portion 56a protrudes in the horizontal direction, and in particular, the onboard performance can be improved.

  Therefore, in the first embodiment, the supply-side resin manifold 52a can be surely broken at the breaking portion 58a by a load from the outside with a simple configuration, and a liquid junction due to the terminal terminal 46a getting wet is possible. The effect that it becomes possible to prevent as much as possible is obtained.

  In the discharge side resin manifold 52b, the same effect as the above supply side resin manifold 52a can be obtained.

  FIG. 5 is a schematic perspective explanatory view of a 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.

  A pipe connection structure 72 is provided on the first end plate 18 a constituting the fuel cell stack 70. The pipe connection structure 72 includes a supply-side resin manifold 52a that is provided in the first end plate 18a and communicates with the cooling medium supply communication hole 30a, and a discharge-side resin manifold 52b that communicates with the cooling medium discharge communication hole 30b.

  Between the supply-side resin manifold 52a and the supply-side pipe connection portion 56a, a breakage portion 74a that breaks preferentially by an external load is located below the terminal terminal 46a that protrudes outward from the first end plate 18a. Is located.

  As shown in FIGS. 5 and 6, the fracture portion 74 a is configured by providing a notch that circulates at a boundary portion between the supply-side resin manifold 52 a and the supply-side pipe connection portion 56 a. By providing the notch, it is preferable that the thickness t1 of the fracture portion 74a is set to be thinner than the thickness t of the supply side pipe connection portion 56a (t1 <t).

  Between the discharge-side resin manifold 52b and the discharge-side pipe connection portion 56b, a breakage portion 74b that breaks preferentially by an external load is provided below the terminal terminal 46b. The broken part 74b is configured in the same manner as the broken part 74a.

  In the second embodiment configured as described above, the fracture portion 74a is configured by providing a notch that circulates at a boundary portion between the supply-side resin manifold 52a and the supply-side pipe connection portion 56a. Accordingly, the fracture portion 74a is a portion where stress is easily concentrated, and can be preferentially broken at the fracture portion 74a. As a result, the same effects as those of the first embodiment can be obtained.

  In the second embodiment, the breakage portion 74a is provided by providing a notch that circulates at the boundary portion between the supply-side resin manifold 52a and the supply-side pipe connection portion 56a. The same effect can be obtained by providing a recess, a partial cutout, or the like.

DESCRIPTION OF SYMBOLS 10,70 ... Fuel cell stack 12 ... Fuel cell 18a, 18b ... End plate 20 ... Electrolyte membrane electrode structure 22, 24 ... Separator 26a ... Oxidant gas supply communication hole 26b ... Oxidant gas discharge communication hole 28a ... Fuel gas Supply communication hole 28b ... Fuel gas discharge communication hole 30a ... Cooling medium supply communication hole 30b ... Cooling medium discharge communication hole 32 ... Oxidant gas flow path 34 ... Fuel gas flow path 36 ... Cooling medium flow path 40 ... Solid polymer electrolyte membrane 42 ... Cathode side electrode 44 ... Anode side electrode 46a, 46b ... Terminal terminals 50, 72 ... Pipe connection structure 52a ... Supply side resin manifold 52b ... Discharge side resin manifold 54a ... Supply side external pipe 54b ... Discharge side external pipe 56a ... Supply Side pipe connection part 56b ... Discharge side pipe connection part 58a, 58b, 74a, 74b ... Broken part 60a, 60 b ... bulge part

Claims (4)

A fuel cell stack in which an electrolyte / electrode structure provided with a pair of electrodes on both sides of an electrolyte and a separator are stacked, and end plates are disposed at both ends in the stacking direction,
A fluid connection hole for circulating a fluid that is a cooling medium or a reactive gas in the stacking direction of the electrolyte / electrode structure and the separator includes a pipe connection structure for connecting to an external pipe,
The pipe connection structure is provided on at least one of the end plates, and a resin manifold communicating with the fluid communication hole;
A pipe connection part formed on the resin manifold and connected to the external pipe;
And having
Between the resin manifold and the pipe connection portion, a breakage portion that is preferentially broken by an external load is provided below the terminal terminal for power extraction that protrudes outward from the end plate. A fuel cell stack characterized by that.   2. The fuel cell stack according to claim 1, wherein the fracture portion is configured by shifting an axis of the pipe connection portion integrally formed with the bulging portion with respect to an axis of the bulging portion provided in the resin manifold. A fuel cell stack.   2. The fuel cell stack according to claim 1, wherein the fracture portion is configured by providing a notch or a recess on an outer periphery of the pipe connection portion.   4. The fuel cell stack according to claim 1, wherein an axis of the pipe connection portion is inclined downward. 5.

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