JP2015201264A - fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To insulate between an end plate and a terminal plate, to thin an insulation plate and to more suitably seal a flow passage.SOLUTION: A fuel cell stack 1 includes: a laminate 3 configured by laminating fuel cel single cells 2; a terminal plate 4 arranged on a lamination-direction end part of the laminate 3; an end plate 5 arranged on the lamination-direction outside of the terminal plate 4; and an insulation plate 6 arranged between the terminal plate 4 and the end plate 5. The end plate 5, the insulation plate 6 and the terminal plate 4 include flow passages 7 penetrated into these plates. An outer edge portion 6a of the insulation plate 6 covers an outer peripheral surface 4p of the terminal plate 4. Inner edge portions 6c of the insulation plate 6 which respectively form inner peripheral surfaces of the flow passages 7 cover the inner peripheral surfaces 4q of the flow passages 7 of the terminal plate 4. An annular storage groove 5 mg is formed on the periphery of each flow passage 7 on a surface 5r of the end plate 5 facing the insulation plate 6 and a seal material 5 ms is stored in the storage groove.

Description

  The present invention relates to a fuel cell stack.

  A laminate in which a plurality of fuel cell single cells are laminated, a conductive terminal plate (high voltage part) arranged at both ends in the lamination direction of the laminate, and a conductivity arranged outside the lamination direction of the terminal plate There is known a fuel cell stack including an end plate (ground portion) and an insulating plate disposed between the terminal plate and the end plate (see Patent Document 1).

JP 2010-140870 A

  The following functions are required for the insulating plate. In the function to insulate between the terminal plate and the end plate, the function to secure the creeping distance to prevent the creeping discharge between the terminal plate and the end plate in the outer periphery, and the flow path through which cooling water, fuel gas and oxidant gas flow It is a sealing (sealing) function.

  In Patent Document 1, in order to secure a creepage distance while making the insulating plate thin, the outer edge portion of the insulating plate is bent toward the end plate side or the terminal plate side. However, there is room for improvement in the structure of the flow path portion of the insulating plate in which the insulating plate must be thinned and sealed while insulating between the terminal plate and the end plate.

  According to the present invention, a stacked body in which a plurality of fuel cell single cells are stacked in the stacking direction, a conductive terminal plate disposed at an end of the stacked body in the stacking direction, and an outer side of the terminal plate in the stacking direction A fuel cell stack comprising a conductive end plate disposed in the substrate and an insulating plate disposed between the terminal plate and the end plate, the end plate, the insulating plate and the terminal plate extending therethrough And the outer edge of the insulating plate extends in the stacking direction so as to cover the outer peripheral surface of the terminal plate or the outer peripheral surface of the end plate. The inner edge of the flow path of the insulating plate forming the peripheral surface extends in the stacking direction so as to cover the inner peripheral surface of the flow path of the terminal plate, and the insulating plate An annular housing groove provided around the flow path surface of the insulating plate facing the surface or the end plate of the end plate facing the, accommodating the sealing member in the housing groove to provide a fuel cell stack.

  While insulating between the end plate and the terminal plate, the insulating plate can be made thinner and more appropriate sealing can be performed.

It is a side view of a fuel cell stack. It is a schematic exploded perspective view of a terminal plate, an insulating plate, and an end plate. It is a fragmentary longitudinal cross-sectional view of a fuel cell stack. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of another Example. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment. It is a fragmentary longitudinal cross-sectional view of the fuel cell stack of still another embodiment.

The fuel cell stack 1 according to the embodiment will be described.
FIG. 1 is a side view of the fuel cell stack 1. Referring to FIG. 1, the fuel cell stack 1 includes a stacked body 3, a terminal plate 4, an end plate 5, and an insulating plate 6. The stacked body 3 is formed by stacking a plurality of fuel cell single cells 2 along the stacking direction S. The terminal plate 4 is disposed at both ends of the stack 3 in the stacking direction S. The end plate 5 is disposed outside the terminal plate 4 in the stacking direction S. The insulating plate 6 is disposed between the terminal plate 4 and the end plate 5. The terminal plate 4 and the end plate 5 are made of a conductive material, and the insulating plate 6 is made of an electrically insulating material.

  Further, the end plates 5 and 5 are fastened to each other by a fastener (not shown) extending in the stacking direction S. As a result, the end plates 5 and 5 are pulled toward each other in the stacking direction S. Therefore, the stacked body 3, the terminal plate 4, the end plate 5, and the insulating plate 6 are in close contact with each other in the stacking direction S.

  The terminal plate 4, end plate 5, and insulating plate 6 each have a rectangular shape when viewed in a cross section perpendicular to the stacking direction S. At that time, the terminal plate 4 and the insulating plate 6 have substantially the same size. On the other hand, the end plate 5 is approximately the same size or slightly larger than the terminal plate 4 and the insulating plate 6.

  The terminal plate 4, the insulating plate 6 and the end plate 5 positioned at one end in the stacking direction S of the fuel cell stack 1 penetrate the terminal plate 4, the insulating plate 6 and the end plate 5 in the stacking direction S, and the fuel cell stack 1. Are provided with a plurality of flow passages 7 from the outside to the laminated body 3. In these flow passages 7, a supply path for supplying a fuel gas such as hydrogen to the stack 3, a discharge path for discharging the fuel gas from the stack 3, and a supply for supplying an oxidant gas such as air to the stack 3 A discharge path for discharging the oxidant gas from the stacked body 3, a supply path for supplying cooling water to the stacked body 3, and a discharge path for discharging cooling water from the stacked body 3.

  Each fuel cell single cell 2 has an anode electrode and a cathode electrode (not shown). The anode electrode is electrically connected to one terminal plate 4, and the cathode electrode is electrically connected to the other terminal plate 4. Connected. In the single fuel cell 2, electric energy is generated by an electrochemical reaction between the fuel gas and the oxidant gas supplied to the single fuel cell 2. Electric energy generated in the single fuel cell 2 is taken out of the fuel cell stack 1 through the terminal plate 4. The electrical energy extracted from the fuel cell stack 1 is supplied to, for example, an electric motor for driving an electric vehicle or a capacitor. The end plate 5 is grounded.

  FIG. 2 is a schematic exploded perspective view of the terminal plate, the insulating plate, and the end plate. FIG. 3 is a partial longitudinal sectional view of the fuel cell stack.

  As shown in FIGS. 2 and 3, the insulating plate 6 includes an outer edge portion 6a, a flat plate portion 6b, and an inner edge portion 6c. The flat plate portion 6 b is a rectangular flat plate portion sandwiched between the end plate 5 and the terminal plate 4 and has an opening that forms the flow passage 7. The outer edge portion 6a is a rectangular frame-shaped portion provided on the outer edge of the flat plate portion 6b. The outer edge portion 6 a extends in the stacking direction S from the outer peripheral surface of the flat plate portion 6 b so as to cover the outer peripheral surface 4 p of the terminal plate 4. In other words, the outer edge portion 6 a is provided such that the flat plate portion 6 b is bent from the outer peripheral surface to the outer peripheral surface 4 p side of the terminal plate 4. The inner edge portion 6 c is a cylindrical portion that forms the inner peripheral surface of the flow path 7 of the insulating plate 6. The inner edge portion 6 c extends in the stacking direction S from the flat plate portion 6 b so as to cover the inner peripheral surface 4 q of the flow passage 7 of the terminal plate 4. In other words, the inner edge portion 6 c is provided such that the flat plate portion 6 b is bent from the opening portion toward the flow passage 7 of the terminal plate 4. Each of the outer edge portion 6a and the inner edge portion 6c extends from the flat plate portion 6b to the surface 4s of the terminal plate 4 on the laminated body 3 side. In this case, the insulating plate 6 can also be regarded as having a recess defined by the flat plate portion 6b, the outer edge portion 6a, and the inner edge portion 6c.

  The terminal plate 4 has a flat plate shape and has an opening that forms the flow passage 7. In the embodiment shown in FIG. 3, the terminal plate 4 is covered with an insulating plate 6 except for the surface 4s on the laminated body 3 side. That is, the outer peripheral surface 4 p of the terminal plate 4 is covered with the outer edge portion 6 a of the insulating plate 6, and the surface 4 r of the terminal plate 4 on the insulating plate 6 side is covered with the flat plate portion 6 b of the insulating plate 6. The peripheral surface 4q is covered with the inner edge 6c of the insulating plate 6. The terminal plate 4 is protected from the fluid flowing in the flow passage 7 by the inner edge portion 6c. The inner edge 6 c of the insulating plate 6 forms the inner peripheral surface of the flow passage 7 of the terminal plate 4. In this case, it can also be said that the terminal plate 4 is fitted in the recess of the insulating plate 6.

  The end plate 5 has a flat plate shape and has an opening for the flow passage 7. A surface 5 r of the end plate 5 on the insulating plate 6 side is in contact with the flat plate portion 6 b of the insulating plate 6. A resin-made inner cylinder portion 5 c is provided on the inner peripheral surface 5 q of the flow passage 7 of the end plate 5. The inner cylinder portion 5 c covers the inner peripheral surface of the flow path 7 of the end plate 5. The end plate 5 is protected from the fluid flowing in the flow passage 7 by the inner cylinder portion 5c.

  The inner cylinder portion 5c includes a flange portion 5c1, a cylindrical portion 5c2, and a flange portion 5c3. The cylindrical portion 5 c 2 is a cylindrical portion that covers the inner peripheral surface 5 q of the flow path 7 of the end plate 5, and extends from the surface 5 r on the insulating plate 6 side to the surface 5 s on the opposite side of the insulating plate 6. The flange portion 5c3 is an annular portion that extends radially from one end of the cylindrical portion 5c2 along the surface 5r. In other words, the flange portion 5c3 is provided such that the cylindrical portion 5c2 is bent from one end thereof to the surface 5r side. The surface of the flange portion 5c3 forms a part of the surface 5r of the end plate 5 on the insulating plate 6 side. The flange portion 5c1 is an annular portion that extends radially from the other end of the cylindrical portion 5c2 along the surface 5s. In other words, the flange portion 5c1 is provided such that the cylindrical portion 5c2 is bent from the other end to the surface 5s side. The surface of the flange portion 5c1 forms a part of the surface 5s of the end plate 5 opposite to the insulating plate 6.

  In the embodiment shown in FIGS. 2 and 3, the inner cylinder portion 5c of the end plate 5 is provided with a seal structure 5m for sealing the flow passage 7 around the flow passage 7 on the surface 5r. The seal structure 5m performs sealing (sealing) of the flow path 7 between the insulating plate 6 and the end plate 5. The seal structure 5m is provided with an annular housing groove 5mg provided around the flow passage 7 of the flange portion 5c3. A sealing material 5 ms such as an O-ring is accommodated in the accommodation groove 5 mg. When the sealing material 5 ms is pressed against the surface 6 s of the insulating plate 6, the flow path 7 between the insulating plate 6 and the end plate 5 is sealed.

  The insulating plate 6 is not particularly limited as long as it is a material having electrical insulating properties. In the embodiment according to the present invention, the insulating plate 6 is made of an electrically insulating resin, for example, a thermoplastic resin such as nylon or polyphenylene sulfide (PPS), or a thermosetting resin such as an unsaturated polyester resin. Further, the inner cylinder portion 5 c can be formed of the same material as the insulating plate 6.

  The thickness of the insulating plate 6 is determined by the insulating characteristics of the material having electrical insulation used and the voltage applied thereto. In the embodiment according to the present invention, the thickness is preferably 1 mm or more from the viewpoint of suppressing defects such as pin holes in the insulating plate 6 and securing the sealing performance in the seal structure 5 m.

  Now, the potential of the terminal plate 4 is high, while the end plate 5 is grounded. Therefore, if the thickness t of the insulating plate 6 is reduced, the terminal plate 4 and the end plate 5 are too close to each other, and there is a risk that creeping discharge occurs between the terminal plate 4 and the end plate 5. However, in the embodiment according to the present invention, the outer peripheral surface 4p of the terminal plate 4 is covered with the outer edge portion 6a of the insulating plate 6, so that the creepage distance CD between the terminal plate 4 and the end plate 5 (= the length of the outer edge portion 6a). The thickness D1 + thickness d1) of the outer edge portion 6a can be increased. Therefore, the thickness t of the insulating plate 6 can be reduced. That is, the weight and cost of the fuel cell stack 1 can be reduced while suppressing the occurrence of creeping discharge between the terminal plate 4 and the end plate 5.

  At this time, in the embodiment according to the present invention, a seal structure 5 m is provided around the flow path 7 between the end plate 5 and the insulating plate 6. With this seal structure 5m, the flow path 7 between the end plate 5 and the insulating plate 6 can be reliably sealed.

  Regarding the seal of the flow path 7 between the insulating plate 6 and the end terminal 4, the inner edge 6 c covers the inner peripheral surface 4 q of the end terminal 4 on the flow path 7 side, and the insulating plate 6 and the end terminal 4 Since the boundary does not face the flow path 7, no seal is necessary. In other words, the inner passage portion 6 c of the insulating plate 6 seals the flow path 7 between the insulating plate 6 and the end terminal 4.

  FIG. 4 is a partial longitudinal sectional view of a fuel cell stack according to another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 3 in that the insulating plate 6 further includes at least one of an outer edge extension portion 6ae and an inner edge extension portion 6ce. The outer edge extension portion 6ae is an extension portion of the outer edge portion 6a, and wraps around from the end of the outer edge portion 6a to the surface of the terminal plate 4 on the side of the laminate 3 (surface facing the surface 4r in contact with the insulating plate 6) 4s. Is provided. The outer edge extended portion 6ae further increases the creepage distance CD by the length d2. That is, the creepage distance CD is (the length D1 of the outer edge portion 6a + the thickness d1 of the outer edge portion 6a + the length d2 of the outer edge extension portion 6ae). Thereby, even if the thickness t of the flat plate portion 6b of the insulating plate 6 is further reduced, the creepage distance CD can be secured. In other words, the thickness t can be further reduced as compared with the case of FIG.

  On the other hand, the inner edge extension portion 6ce is an extended portion of the inner edge portion 6c, and is provided so as to go around from the end portion of the inner edge portion 6c to the surface 4s on the laminated body 3 side of the terminal plate 4. The inner edge extension portion 6ce covers the boundary between the insulating plate 6 and the terminal plate 4 further away from the flow path 7 side, so that the flow path 7 between the insulating plate 6 and the terminal plate 4 is more reliably secured. Can be sealed.

  In the fuel cell stack 1, both the outer edge extension 6ae and the inner edge extension 6ce may be used, or one of them may be used.

  FIG. 5 is a partial vertical cross-sectional view of a fuel cell stack in still another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 3 in that the seal structure is provided not on the end plate 5 but on the insulating plate 6. The flat plate portion 6 b of the insulating plate 6 includes a seal structure 6 m that seals the flow passage 7 around the flow passage 7 on the surface 6 s facing the surface 5 r of the end plate 5. The seal structure 6 m seals (seals) the flow path 7 between the insulating plate 6 and the end plate 5. The seal structure 6m is provided with an annular receiving groove 6mg provided around the flow passage 7 of the flat plate portion 6b. A sealing material 6ms such as an O-ring is accommodated in the accommodating groove 6mg. When the sealing material 6 ms is pressed against the surface 5 r of the end plate 5, the flow path 7 between the insulating plate 6 and the end plate 5 is sealed. Also in this case, the flow path 7 can be more appropriately sealed as in the case of FIG.

  FIG. 6 is a partial vertical cross-sectional view of a fuel cell stack in still another embodiment of the present invention. This embodiment is different from the embodiment of FIG. 5 in that the insulating plate 6 further includes an outer edge extension portion 6ae and an inner edge extension portion 6ce. The outer edge extension portion 6ae and the inner edge extension portion 6ce are as described in the embodiment of FIG. Even in this case, similarly to the case of FIG. 4, the thickness t of the insulating plate 6 can be further reduced by the outer edge extended portion 6ae, and the flow path 7 can be more appropriately sealed by the inner edge extended portion 6ce. it can.

  7 to 10 are partial longitudinal sectional views of a fuel cell stack in still another embodiment of the present invention. These embodiments are different from the embodiments of FIGS. 3 to 6 in that the outer edge portion 6a of the insulating plate 6 extends so as to cover the entire outer peripheral surface 5p of the end plate 5 instead of the terminal plate 4. To do. As a result, the creepage distance CD between the end plate 5 and the terminal plate 4 is not the thickness t of the insulating plate 6 (the flat plate portion 6b) but the length D2 of the outer edge portion 6a and the thickness d1 of the outer edge portion 6a. Become sum. Thereby, even if the thickness t of the insulating plate 6 is reduced, the creeping distance CD (= D2 + d1) can be increased. On the other hand, in the embodiment shown in FIGS. 7 and 8, the seal structure 5 m is provided on the end plate 5 as in the embodiment shown in FIGS. 3 and 4. On the other hand, in the embodiment shown in FIGS. 9 and 10, the sealing structure 6 m is provided on the insulating plate 6 as in the embodiment shown in FIGS. 5 and 6. In the embodiment shown in FIGS. 7 and 9, the surface 4 s of the terminal plate 4 on the laminated body 3 side is not covered with the insulating plate 6, as in the embodiment shown in FIGS. 3 and 5. On the other hand, in the embodiment shown in FIGS. 8 and 10, the surface 4 s on the laminated body 3 side of the terminal plate 4 is covered with the insulating plate 6, as in the embodiment shown in FIGS. 4 and 6. As a result, the embodiment shown in FIGS. 7 to 10 can achieve the same effects as the embodiments of FIGS. 3 to 6 in addition to the above-described effects.

  As described above, the fuel cell stacks of the respective embodiments have a simple structure, insulate the end plate from the terminal plate, thin the insulating plate, and perform a more appropriate seal. It is possible to provide a fuel cell stack having a flow path capable of performing the following.

DESCRIPTION OF SYMBOLS 1 Fuel cell stack 2 Fuel cell single cell S Stacking direction 3 Stack body 4 Terminal plate 4p Outer peripheral surface 4q Inner peripheral surface 5 End plate 5r Surface 5mg Housing groove 5ms Sealing material 6 Insulating plate 6a Outer edge 6c Inner edge 6s Surface 6mg Housing groove 6ms Seal material 7 Flow path

Claims (1)

A laminate in which a plurality of fuel cell single cells are laminated along the lamination direction;
A conductive terminal plate disposed at an end of the laminate in the laminating direction;
A conductive end plate disposed outside the terminal plate in the stacking direction;
An insulating plate disposed between the terminal plate and the end plate;
A fuel cell stack comprising:
The end plate, the insulating plate, and the terminal plate have flow paths that pass through them and reach the stack from the outside of the fuel cell stack,
The outer edge of the insulating plate extends in the stacking direction so as to cover the outer peripheral surface of the terminal plate or the outer peripheral surface of the end plate,
An inner edge portion of the insulating plate forming an inner peripheral surface of the flow passage extends in the stacking direction so as to cover an inner peripheral surface of the flow passage of the terminal plate,
An annular housing groove was provided around the flow path on the surface of the end plate facing the insulating plate or the surface of the insulating plate facing the end plate, and a sealing material was housed in the housing groove.
Fuel cell stack.

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