JP2009199910A - Conclusion structure of fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fastening structure of a fuel cell stack in which the deformation of an end plate caused by the swelling of a laminate can be suppressed, and downsizing and weight reduction can be promoted. <P>SOLUTION: The fastening structure (100) of the fuel cell stack is equipped with a fuel cell stack (10) including a laminate (14) in which a plurality of cells (12) are laminated and a pair of end plates (16) pinching the laminate in a laminating direction of the cell, a vehicle frame (40), and a pressing member (50) fixed to the vehicle frame between the vehicle frame and the end plate to give pressing force to the end plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fastening structure for a fuel cell stack.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. Since this fuel cell is excellent in terms of the environment and can realize high energy efficiency, it has been widely developed as a future energy supply system.

  A fuel cell is generally used as a fuel cell stack including a stacked body in which a plurality of cells are stacked, a pair of end plates that sandwich the stacked body, and a connecting portion that connects the pair of end plates (for example, Patent Document 1).

  Here, in order to mount the fuel cell stack on a vehicle, it is required to reduce the size and weight of the fuel cell stack. Patent Document 1 discloses an end plate (plate) provided between a separator and an end plate that is thicker on the inner side than the peripheral side of the surface that contacts the laminate, and presses the laminate against both end plates. A fuel cell stack is disclosed.

  Patent Document 2 discloses a fuel cell in which a fuel cell stack is disposed between a vehicle bottom plate and a vehicle compartment or between a vehicle bottom plate and a cargo floor, and fuel storage means is disposed behind the fuel cell stack. An apparatus is disclosed.

JP 2003-151611 A JP 2003-17107 A

  By the way, in the fuel cell stack, the laminate may expand during power generation. In addition, during power generation, the end plate may also expand due to heat generated by power generation. When the expansion of the laminate and the expansion of the end plate (hereinafter, these expansions are referred to as “expansion of the laminate, etc.”), the end plate may be deformed. In this case, the power generation performance of the fuel cell stack may be reduced. Further, if the end plate is made thicker to increase the rigidity against deformation, the fuel cell stack becomes larger and heavier. When the fuel cell stack becomes larger and heavier, it may become difficult to mount the fuel cell stack on the vehicle, or the entire vehicle may increase in weight and fuel consumption may deteriorate.

  In addition, by applying the technique according to Patent Document 1 and increasing the thickness on the inner side of the peripheral edge side of the surface that contacts the laminated body of the end plates, the fuel cell stack becomes larger and heavier as the end plates are made thicker. To do. Moreover, it is difficult to suppress the deformation of the end plate due to the expansion of the laminated body only by applying the technique according to Patent Document 2.

  An object of the present invention is to provide a fastening structure of a fuel cell stack that can suppress deformation of an end plate due to expansion of a laminated body and the like and can reduce the size and weight of the fuel cell stack.

  A fastening structure of a fuel cell stack according to the present invention includes a fuel cell stack including a stacked body in which a plurality of cells are stacked, and a pair of end plates that sandwich the stacked body in the stacking direction of the cells, a vehicle frame, And a pressing member that is fixed to the vehicle frame between the vehicle frame and the end plate and applies a pressing force to the end plate.

  According to the fastening structure of the fuel cell stack according to the present invention, the pressing member is fixed to the vehicle frame to apply a pressing force to the end plate using the rigidity of the vehicle frame. Thereby, the deformation | transformation of an end plate by expansion etc. of a laminated body can be suppressed. Further, since it is not necessary to increase the thickness of the end plate in order to increase the rigidity against deformation of the end plate, the fuel cell stack can be reduced in size and weight.

  In the above configuration, the pair of end plates may be fastened to each other by at least four shafts, and the pressing member may apply a pressing force to the center point of any of the four shafts in the end plate. According to this configuration, the pressing member can apply a pressing force to a portion where the deformation amount of the end plate is large. Thereby, the deformation | transformation of an end plate by expansion | swelling etc. of a laminated body can be suppressed efficiently.

  In the above configuration, the pressing member may be made of a material having a higher Young's modulus than the end plate. According to this configuration, a larger pressing force can be applied to the end plate.

  ADVANTAGE OF THE INVENTION According to this invention, the fastening structure of the fuel cell stack which can aim at size reduction and weight reduction of a fuel cell stack while being able to suppress a deformation | transformation of an end plate by expansion | swelling etc. of a laminated body can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described.

  A fuel cell stack fastening structure 100 according to Embodiment 1 of the present invention will be described. FIG. 1 is a schematic perspective view illustrating a fastening structure 100 for a fuel cell stack according to a first embodiment. FIG. 1 is a schematic transparent view of a vehicle (not shown) on which the fuel cell stack 10 is mounted as viewed from the upper side (vehicle ceiling side). In FIG. 1, the direction of the front side of the vehicle is indicated by an arrow. The fuel cell stack fastening structure 100 includes a fuel cell stack 10, a stack case 30, a front side member 41, and a block 50.

  The fuel cell stack 10 includes a stacked body 14 in which a plurality of cells 12 are stacked, and a pair of end plates 16 that sandwich the stacked body 14. The fuel cell stack 10 is held in the stack case 30. Specifically, the fuel cell stack 10 is held in the stack case 30 so that the end surface of the end plate 16 opposite to the stacked body 14 is substantially parallel to the longitudinal direction of the front side member 41. The method for holding the fuel cell stack 10 in the stack case 30 is not particularly limited.

  The cell 12 is not particularly limited as long as it is a fuel cell that generates power using hydrogen and oxygen as fuel. In this embodiment, a polymer electrolyte fuel cell is used as the cell 12. In this case, the cell 12 includes an electrolyte membrane (not shown), an anode (not shown) and a cathode (not shown) that sandwich the electrolyte membrane, and a pair of diffusion layers (not shown) that sandwich the anode and cathode. ) And.

  The pair of end plates 16 are fastened to each other by the connecting portion 18 and pressed to the laminated body 14 side by a block 50 described later. Thereby, the end plate 16 gives a compressive stress to the laminate 14. The end plate 16 is made of a member having rigidity (Young's modulus) that can withstand the pressing force of the block 50. The fuel cell stack 10 may include a terminal as a current collector and an insulator as an insulator in this order from the stack 14 side between the end plate 16 and the stack 14.

  The connecting portion 18 includes a shaft 20 and a pair of bolts 22. Each end of the shaft 20 abuts on the end plate 16. The pair of bolts 22 are screwed to the shaft 20 via the end plate 16. Thereby, the pair of end plates 16 are fastened by the connecting portion 18. The shaft 20 is made of a rigid member, and is made of a metal such as stainless steel, for example.

  The connecting portion 18 may include a stud bolt instead of the shaft 20 and may include a nut that is screwed into the stud bolt instead of the bolt 22. The distance between the pair of end plates 16 is held substantially constant by the connecting portion 18, and the end plate 16 supports the stacked body 14.

  The stack case 30 is not particularly limited as long as it can hold the fuel cell stack 10 inside. In the present embodiment, the stack case 30 has a box shape in which plate-like members are combined so as to surround the six surfaces of the fuel cell stack 10. The stack case 30 is mounted on the bottom plate of the vehicle, for example, by a mounting bracket (not shown). Further, the stack case 30 is formed with a through hole through which the block 50 passes.

  FIG. 2 is a schematic perspective view showing the frame 40 of the vehicle. As shown in FIG. 2, the frame 40 has a separate frame structure in which a pair of front side members 41, a pair of floor frames 42, and a pair of rear side members 43 are connected. In the present embodiment, the fuel cell stack 10 is disposed in a region 200 between the pair of front side members 41.

  Referring to FIG. 1 again, the block 50 is inserted through a through hole provided in the stack case 30. One end of the block 50 is fixed to the front side member 41, and the other end supports the end plate 16. In this embodiment, a rigid member made of metal such as steel or aluminum alloy is used as the block 50.

  One end of the block 50 is fixed to the front side member 41, and the other end supports the end plate 16, so that the block 50 applies a pressing force to the end plate 16 using the rigidity of the front side member 41. . That is, the block 50 has a function as a pressing member.

  The block 50 is preferably made of a material having a higher Young's modulus than the end plate 16. This is because a larger pressing force can be applied to the end plate 16 in this case. The shape of the block 50 is not particularly limited as long as a pressing force can be applied to the end plate 16.

  FIG. 3 is a perspective view of the fuel cell stack 10. In FIG. 3, the direction of the front side of the vehicle is indicated by an arrow. As shown in FIG. 3, one connecting portion 18 is disposed at each corner of the end plate 16 and at the center of each long side of the end plate 16. Therefore, in the present embodiment, the end plate 16 is fastened by the six connecting portions 18. Here, the center points of the four connecting portions 18 adjacent to each other are referred to as points 70 and 72, respectively. Each block 50 is arranged to press the point 70 and the point 72, respectively.

  Next, the operation of the fuel cell stack fastening structure 100 will be described. FIG. 4A is a schematic diagram showing the fuel cell stack 10 when the fastening structure 100 of the fuel cell stack does not include the block 50. As shown in FIG. 4A, when the fuel cell stack 10 generates power, the end plate 16 expands due to heat generated by the power generation. Moreover, the laminated body 14 also expands with power generation. Thereby, each end plate 16 is deformed so as to protrude and curve on the opposite side to the laminate 14. In this case, the amount of deformation at the points 70 and 72 of the end plate 16 becomes large.

  When the end plate 16 is deformed, the compressive stress applied to the laminate 14 by the end plate 16 becomes non-uniform. As a result, the adhesion between the adjacent cells 12 deteriorates as the compressive stress decreases. When the adhesion between the adjacent cells 12 deteriorates, the contact resistance between the cells 12 increases, and thus the power generation performance of the fuel cell stack 10 may be reduced.

  As a method for suppressing the deformation of the end plate 16 due to the expansion of the laminate 14, a method of increasing the rigidity against the deformation of the end plate 16 by increasing the thickness of the end plate 16 can be considered. However, when the end plate 16 is thickened, the fuel cell stack 10 becomes larger and heavier. If the fuel cell stack 10 is increased in size and weight, it may be difficult to mount the fuel cell stack 10 on a vehicle, or the weight of the entire vehicle may increase and fuel consumption may deteriorate.

  FIG. 4B is a schematic diagram illustrating the operation of the fastening structure 100 of the fuel cell stack according to the present embodiment. As shown in FIG. 4B, the block 50 applies a pressing force to the end plate 16, so that the deformation of the end plate 16 due to the expansion of the laminate 14 is suppressed.

  According to the fastening structure 100 of the fuel cell stack according to the present embodiment, the block 50 is fixed to the front side member 41, thereby applying a pressing force to the end plate 16 using the rigidity of the front side member 41. give. Thereby, the deformation | transformation of the end plate 16 by the expansion | swelling etc. of the laminated body 14 can be suppressed. Further, since it is not necessary to increase the thickness of the end plate 16 in order to increase the rigidity against deformation of the end plate 16, the fuel cell stack 10 can be reduced in size and weight.

  Further, in this embodiment, the block 50 applies a pressing force to a portion where the deformation amount of the end plate 16 increases. Therefore, the deformation of the end plate 16 due to the expansion of the laminate 14 can be efficiently suppressed.

  In the present embodiment, the block 50 is fixed to the front side member 41, but is not limited thereto. The location where the block 50 is fixed to the frame 40 is not particularly limited. For example, when the fuel cell stack 10 is disposed between the pair of floor frames 42, the block 50 may be fixed to the floor frame 42. Further, when the fuel cell stack 10 is disposed between the pair of rear side members 43, the block 50 may be fixed to the rear side member 43. As described above, the block 50 may be fixed to any one of the frames 40.

  The frame 40 may be a monocoque frame, for example. In this case, for example, when the fuel cell stack 10 is disposed between the front side members of the monocoque frame, the block 50 may be fixed to the front side member.

  In the present embodiment, six shafts 20 are provided, but the number of shafts 20 is not particularly limited. Moreover, the pressing location of the block 50 is not specifically limited. However, in the case where four or more shafts 20 are provided, the deformation of the end plate 16 can be efficiently suppressed by arranging the block 50 at the center point of any four shafts 20.

  The fuel cell stack 10 may have a configuration in which a plurality of stacked bodies 14 are arranged in parallel. Even in this case, the deformation of the end plate 16 can be suppressed by applying a pressing force to the end plate 16 by the block 50. Further, when four or more shafts 20 are provided, the block 50 is disposed at the center point of any four shafts 20, whereby the deformation of the end plate 16 can be efficiently suppressed.

  Next, a fastening structure 100a for a fuel cell stack according to Embodiment 2 of the present invention will be described. FIG. 5 is a schematic permeation view showing the fastening structure 100a of the fuel cell stack according to the second embodiment. The fuel cell stack fastening structure 100a differs from the fuel cell stack fastening structure 100 of FIG. 1 in that a stack case 30a is provided instead of the stack case 30 and a block 50a is provided instead of the block 50. 1 is different from the fastening structure 100 of the fuel cell stack of FIG. 1 in that the front side member 41 does not contribute to the fastening of the fuel cell stack 10. Other configurations are the same as those of the fuel cell stack fastening structure 100 of FIG.

  The stack case 30a does not have a through-hole for allowing the block 50a to pass therethrough, and has rigidity sufficient to apply a fastening force to the fuel cell stack 10 via the block 50a. And the stack case 30 in FIG. The stack case 30a is made of, for example, stainless steel.

  The block 50a is different from the block 50 of FIG. 1 in that the block 50a is fixed to the inner wall surface of the stack case 30a instead of the front side member 41. The other configuration is the same as that of the block 50, and thus the description thereof is omitted.

  According to the fuel cell stack fastening structure 100a according to the present embodiment, the block 50a can apply a pressing force to the end plate 16 by utilizing the rigidity of the stack case 30a. Thereby, the deformation | transformation of the end plate 16 by the expansion | swelling etc. of the laminated body 14 can be suppressed. Further, since it is not necessary to increase the thickness of the end plate 16 in order to increase the rigidity against deformation of the end plate 16, the fuel cell stack 10 can be reduced in size and weight.

  The fuel cell stack fastening structure may be a combination of the fuel cell stack fastening structure 100 according to the first embodiment and the fuel cell stack fastening structure 100a according to the second embodiment. For example, of the four blocks 50a shown in FIG. Good. Even in this case, the deformation of the end plate 16 due to the expansion of the laminated body 14 can be suppressed, and the fuel cell stack 10 can be reduced in size and weight.

FIG. 1 is a schematic transparent view showing a fastening structure of a fuel cell stack according to the first embodiment. FIG. 2 is a schematic perspective view showing the frame of the vehicle. FIG. 3 is a perspective view of the fuel cell stack. FIG. 4A is a schematic diagram illustrating the fuel cell stack when the fastening structure of the fuel cell stack according to the first embodiment does not include a block. FIG. 4B is a schematic diagram illustrating an operation of the fastening structure of the fuel cell stack according to the first embodiment. FIG. 5 is a schematic transparent view illustrating a fastening structure of a fuel cell stack according to the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell stack 12 Cell 14 Laminated body 16 End plate 18 Connection part 20 Shaft 22 Bolt 30 Stack case 40 Frame 41 Front side member 42 Floor frame 43 Rear side member 50 Block 70, 72 Point 100 Fastening structure of fuel cell stack

Claims (3)

A fuel cell stack including a stacked body in which a plurality of cells are stacked, and a pair of end plates that sandwich the stacked body in the stacking direction of the cells;
A vehicle frame;
A fuel cell stack fastening structure comprising: a pressing member that is fixed to the vehicle frame between the vehicle frame and the end plate and applies a pressing force to the end plate. The pair of end plates are fastened to each other by at least four shafts,
2. The fastening structure of a fuel cell stack according to claim 1, wherein the pressing member applies a pressing force to a center point of any four of the shafts in the end plate.   The fastening structure for a fuel cell stack according to claim 1, wherein the pressing member is made of a material having a higher Young's modulus than the end plate.

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