JP2007227059A - Fuel cell and method of manufacturing same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell in which fastening force in the cell stacking direction is equally applied to each cell, and to provide a method of manufacturing the fuel same. <P>SOLUTION: The fuel cell 100 includes a stack 10 formed by stacking stacking components containing a plurality of cells; and an outside member 20 installed on the side surface of the stack and extended in the stacking direction of the stacking member, and a frictional force decreasing means 22 decreasing frictional force between the stacking component and the outside member in the stacking direction. Each stacking component can be moved at the same degree of freedom with the frictional force decreasing means. In this case, the fastening force of the stack is equally dispersed to each stacking component. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell in which a plurality of cells are stacked and a manufacturing method thereof.

  A fuel cell is a device that generally obtains electric energy using hydrogen and oxygen as fuel. This fuel cell is environmentally superior and can realize high energy efficiency, and therefore has been widely developed as a future energy supply system.

  In general, a fuel cell has a stack structure in which a plurality of cells are stacked and fastened with a predetermined load in the stacking direction. In such a stack, if a force is applied in a direction perpendicular to the cell stacking direction, the cell may be displaced. In view of this, a technique for preventing positional displacement of cells by bringing an external restraining member into contact with the side surface of the stack is disclosed (for example, see Patent Document 1).

JP 2005-56814 A

  However, in the technique of Patent Document 1, a frictional force is generated between the stack and the external restraining member on the side surface of the stack. In this case, the cell cannot move smoothly in the stacking direction. As a result, the fastening force in the stacking direction of the stack may not be applied equally to each cell.

  It is an object of the present invention to provide a fuel cell in which the fastening force in the cell stacking direction is equally applied to each cell and a method for manufacturing the fuel cell.

  A fuel cell according to the present invention includes a stack in which laminated parts including a plurality of cells are laminated, and an outer member that is provided on a side surface of the stack and extends in the lamination direction of the laminated parts, and the stacking direction is provided on the stack side of the outer member. Friction force reducing means for reducing the friction force between the laminated component and the outer member is provided.

  In the fuel cell according to the present invention, when an external force, a thermal expansion force, or the like acts in the stacking direction of each stacked component, each stacked component tends to move in the stacking direction. In this case, the frictional force when the laminated parts are moved in the laminating direction is reduced by the frictional force reducing means. As a result, each laminated part can move with the same degree of freedom. In this case, the fastening force of the stack is evenly distributed to each laminated component. Therefore, variation in surface pressure in each cell can be suppressed. As a result, hydrogen leakage in the cell can be prevented and contact resistance in the cell can be reduced.

  The frictional force reducing means may include a plurality of rotating members that can rotate in the stacking direction. In this case, the rotating member rotates when each laminated component tries to move in the laminating direction. Thereby, the frictional force at the time of movement of each laminated component in the lamination direction is reduced. The laminated component may include a recess facing the rotating member, and the rotating member may be rotatable while facing the recess. In this case, the laminated component is positioned by the recess.

  The frictional force reducing means may further include holding means for holding the rotating member so as to be extendable and contractable in a direction substantially perpendicular to the cell stacking direction. The holding means may hold the rotating member by an elastic member. In this case, the external force in the direction substantially perpendicular to the stacking direction can be absorbed by the holding means.

  The frictional force reducing means may further include a belt wound around the plurality of rotating members in common. In this case, when each laminated component tries to move in the laminating direction, the frictional force at the time of moving each laminated component in the laminating direction is reduced by driving the belt. Further, the laminated component may include a spring box. In this case, the external force in the stacking direction, the thermal expansion force of the cells, etc. can be absorbed by the spring box. Further, the frictional force during movement of each laminated component accompanying the expansion and contraction of the spring box is reduced by the frictional force reducing means. Furthermore, the outer member may be fixed to both ends in the stacking direction of the multilayer component.

  The fuel cell manufacturing method according to the present invention includes a preparation step of preparing a first base material in which a plurality of outer members for guiding a laminated component to a predetermined region are arranged at predetermined intervals, and an outer member A first laminating step of sequentially laminating the laminated component on the first base material while guiding the frictional force between the laminated component and the outer member in the laminating direction of the laminated component on the surface of the outer member on the laminated component side Friction force reducing means for reducing the above is provided.

  In the fuel cell manufacturing method according to the present invention, each laminated component is positioned by the outer member, and the frictional force between the outer member and each laminated component is reduced by the frictional force reducing means. As a result, when the stack is fastened, the fastening force is equally applied to each laminated component. Moreover, damage of each laminated component can be prevented by reducing the frictional force. Thereby, the manufacturing cost can be reduced. Further, the outer member can be used as a component of the fuel cell. Therefore, the process of attaching / detaching the outer member can be omitted.

  The frictional force reducing means may include a plurality of rotating members that can rotate in the stacking direction, and the first stacking step may be a step of stacking stacked components while rotating the rotating member. In this case, the rotating member rotates when the laminated components are laminated. Thereby, the frictional force at the time of laminating each laminated component is reduced.

  The laminated component may include a concave portion facing the rotating member, and the first laminating step may be a step of laminating the laminated component with the concave portion facing the rotating member. In this case, the laminated component can be positioned by the recess.

  The frictional force reducing means may further include a belt wound around a plurality of rotating members in common, and the first lamination step may be a step of laminating laminated components while driving the belt. In this case, the belt is driven when the laminated parts are laminated. Thereby, the frictional force at the time of laminating each laminated component is reduced.

  A second laminating step of laminating the second substrate on the laminated component after laminating the laminated component; and applying the predetermined pressure on the first substrate side to the second substrate while using the second substrate as the outer member A fastening step of fastening may be further included. The outer member can be divided in the stacking direction, and may further include a separation step of separating the outer member on the upper side of the laminated component after the fastening step. In this case, it is possible to prevent the position of the laminated component from being shifted over the process from the lamination process to the fastening process. Further, after the stack is fastened, the unnecessary outer member can be removed by a simple operation.

  According to the present invention, the fastening force of the stack can be evenly distributed to each cell.

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

  FIG. 1 is a perspective view showing the overall configuration of a fuel cell 100 according to a first embodiment of the present invention. As shown in FIG. 1, the fuel cell 100 includes a stack 10 and a plurality of outer members 20. The stack 10 has a structure in which an insulator 2a, a terminal 3a, a plurality of cells 4, a terminal 3b, an insulator 2b, a spring box 5, and an end plate 1b are sequentially stacked on the end plate 1a.

  The end plates 1 a and 1 b are members for sandwiching other laminated parts included in the stack 10. The insulators 2a and 2b are made of an insulator and prevent leakage of generated power from the cell 4. The terminals 3a and 3b are provided with wiring for taking out the generated power from the cell 4 to the outside. The cell 4 has a structure in which a separator, an anode, an electrolyte, a cathode, and a separator are sequentially laminated, and generates power using a fuel gas and an oxidant gas. In the present embodiment, the number of stacked cells 4 is, for example, about several hundred.

  The spring box 5 includes a plurality of springs that can be expanded and contracted in the stacking direction of the stacked components. Thereby, the spring box 5 can absorb the external force applied in the stacking direction of each stacked component. Further, the spring box 5 can absorb internal forces such as thermal expansion force of each cell 4. A predetermined pressure is applied between the end plate 1a and the end plate 1b. Thereby, it is suppressed that each laminated component is displaced in the direction perpendicular to the lamination direction.

  The outer member 20 is a member extending from each corner of the end plate 1a to each corresponding corner of the end plate 1b. Each outer member 20 is fixed by bolts or the like on both side surfaces sandwiching each corner of the end plates 1a and 1b. Thereby, the position shift of each laminated component can be prevented.

  Hereinafter, the details of the outer member 20 will be described with reference to FIGS. 2 and 3. FIG. 2 is a view when the outer member 20 is viewed in the direction of the arrow X in FIG. FIG. 3 is a view when the outer member 20 is viewed in the direction of the arrow Y in FIG. As shown in FIGS. 2 and 3, the outer member 20 includes a base material 21, a plurality of bearings 22, a plurality of holding members 23, and a belt 24. The belt 24 is made of rubber such as nitrile or chloroprene.

  The base material 21 has a shape having an L-shaped cross section when viewed in the direction of the arrow X. A pair of holes 25 are formed in each surface of the base material 21 at a predetermined interval in the stacking direction of the stacked components. Each hole 25 has a small diameter at the end on the stack 10 side. The holding member 23 includes two rod-like members arranged in parallel with the holes 25. This rod-shaped member includes a reduced diameter portion having a diameter smaller than the diameter of the end portion of the hole 25 on the stack 10 side at the center portion. Further, the diameter of the rod-shaped member other than the reduced diameter portion is larger than the diameter of the end portion of the hole 25 on the stack 10 side. Thereby, the reduced diameter portion of the rod-shaped member is slidable in the hole 25. Further, it is possible to prevent the holding member 23 from falling out of the hole 25 toward the stack 10 side.

  The holding member 23 holds the bearing 22 so as to be rotatable in the stacking direction of the stacked components at the end of the two rod-shaped members on the stack 10 side. On the outer periphery of the rod-shaped member, a spring 26 that can expand and contract in the length direction of the rod-shaped member is provided. Thereby, the bearing 22 can expand and contract in parallel with the hole 25, and can bias a predetermined biasing force against the stack 10. The belt 24 is wound around the plurality of bearings 22.

  In the fuel cell 100 according to the present embodiment, when an external force, a thermal expansion force, or the like works in the stacking direction of each stacked component, each stacked component tends to move in the stacking direction because the spring box 5 can expand and contract. In this case, the bearing 22 rotates with the driving of the belt 24 accompanying the movement of each laminated component. Thereby, the frictional force at the time of movement of each laminated component in the lamination direction is reduced. As a result, each laminated part can move with the same degree of freedom. In this case, the fastening force of the stack 10 is evenly distributed to each cell 4. Therefore, variations in surface pressure in each cell 4 can be suppressed. As a result, hydrogen leakage in the cell 4 can be prevented and contact resistance in the cell 4 can be reduced.

  Note that the belt 24 is not necessarily provided. In this case, by rotating each bearing 22, each laminated component can move with the same degree of freedom. Further, the frictional force reducing means for moving the laminated parts is not limited to the above bearing structure. The frictional force reducing means may be any means that is held so as to be rotatable in the laminating direction of each laminated component. The frictional force reducing means may be, for example, a pulley.

  Further, the frictional force reducing means does not necessarily need to have a biasing force with respect to the stack 10, and may be fixed at a predetermined position. The position where the outer member 20 is provided is not particularly limited. What is necessary is just to arrange | position at the location which fixes the stack | stuck 10 so that each laminated component may not position-shift in the direction perpendicular | vertical to a lamination direction. Furthermore, the diameter of the bearing 22 is not particularly limited. The diameter of the bearing 22 may be changed in consideration of the material of the belt 24, the thickness of the cell 4, and the like. Further, the number of bearings 22 is not particularly limited. The number of the bearings 22 may be changed depending on the diameter of the bearing 22, the number of stacked cells 4, and the like.

  Further, since the fuel cell 100 has the above-described structure, the fastening force of the stack 10 can be evenly distributed to the respective laminated components even in the manufacturing process of the fuel cell 100. The details will be described below. FIG. 4 is a diagram for explaining a method for manufacturing the fuel cell 100. As shown in FIG. 4A, first, the outer member 20 is fixed to the end plate 1 a, and the extension member 30 having the same structure as the outer member 20 is fixed on the outer member 20. The extension member 30 is also provided with a bearing similar to the outer member 20. The connection between the outer member 20 and the extension member 30 can be realized if a recess is formed on one of the upper end of the outer member 20 and the lower end of the extension member 30 and a protrusion that fits the recess is formed on the other. It is.

  Next, as shown in FIG. 4B, the respective laminated components are sequentially laminated on the end plate 1a. In this case, each laminated component is positioned by being guided using the extension member 30 and the outer member 20, and the frictional force between the extension member 30 and the outer member 20 and each laminated component is caused by the rotation of the bearing 22. Reduced. Thereby, damage of each laminated component can be prevented. FIG. 4C shows a state where all the laminated parts are laminated. As shown in FIG. 4 (c), in a state where no fastening force is applied, the laminated length of the entire laminated component is larger than the length of the outer member 20.

  Next, as shown in FIG. 4D, a predetermined pressure is applied to the end plate 1b to reduce the stacking length of the stacked component, and the end plate 1b and the outer member 20 are fixed. In this case, each laminated component moves to the end plate 1a side by applying a fastening force downward from the end plate 1b, but the fastening force of the stack 10 is evenly distributed to each laminated component by the friction reduction function by the bearing 22. Will work. Next, as shown in FIG. 4E, the fuel cell 100 is completed by separating the extension member 30 and the outer member 20.

  As described above, according to the manufacturing method shown in FIG. 4, the fastening force of the stack 10 is equally applied to each laminated component. Moreover, since damage to each laminated component can be prevented, the manufacturing cost can be reduced. Further, the outer member 20 that is a component of the fuel cell 100 can be used as a positioning jig. Therefore, the process of attaching / detaching the positioning jig can be omitted.

  In this embodiment, the bearing 22 corresponds to the friction force reducing means and the rotating member, the spring 26 corresponds to the elastic member, the end plate 1a corresponds to the first base material, and the end plate 1b corresponds to the second base material. Equivalent to.

  Subsequently, a fuel cell 100a according to a second embodiment of the present invention will be described. The difference between the fuel cell 100a and the fuel cell 100 of FIG. 1 is the shape of each laminated component. The details will be described below.

  FIG. 5 is a partially enlarged view of the fuel cell 100a when viewed from the upper surface side of the end plate 1b. As shown in FIG. 5, the recessed part 60 is formed in the location which contacts the bearing 22 in each laminated component. The bearing 22 and the belt 24 move along the recess 60. In this case, each laminated component is positioned by the bearing 22. Therefore, even if an external force in a direction perpendicular to the stacking direction of each laminated component is applied, the position of each laminated component is prevented from being shifted.

  Subsequently, a fuel cell 100b according to a third embodiment of the present invention will be described. FIG. 6 is a perspective view of the fuel cell 100b. The fuel cell 100b is different from the fuel cell 100 of FIG. 1 in that the spring box 5 is not provided. In the fuel cell 100b, the amount of movement of each laminated component is smaller than when the spring box 5 is provided, but each laminated component tends to move by a large external force. In this case, the rotation of the bearing 22 allows each laminated component to return to the original position without receiving a frictional force. Therefore, also in the fuel cell 100b according to the present embodiment, the fastening force of the stack 10 is equally applied to each laminated component. In addition, as shown in FIG. 4, the fastening force of the stack 10 is equally applied to each laminated component in the manufacturing process.

1 is a perspective view showing an overall configuration of a fuel cell according to a first embodiment of the present invention. It is a figure at the time of seeing an outer member in the direction of the arrow X of FIG. It is a figure at the time of seeing an outer member in the direction of arrow Y of FIG. It is a figure for demonstrating the manufacturing method of a fuel cell. It is a partially enlarged view when the fuel cell is viewed from the upper surface side of the end plate. It is a perspective view which shows the whole structure of the fuel cell which concerns on 3rd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b End plate 4 Cell 5 Spring box 10 Stack 20 Outer member 21 Base material 22 Bearing 23 Holding member 24 Belt 26 Spring 30 Extension member 100, 100a, 100b Fuel cell

Claims (14)

A stack in which laminated parts including a plurality of cells are laminated;
An outer member provided on a side surface of the stack and extending in a stacking direction of the stacked component;
2. A fuel cell according to claim 1, wherein a frictional force reducing means for reducing a frictional force between the laminated component and the outer member in the stacking direction is provided on the stack side of the outer member. The fuel cell according to claim 1, wherein the frictional force reducing means includes a plurality of rotating members that are rotatable in the stacking direction. The laminated component includes a recess facing the rotating member,
The fuel cell according to claim 2, wherein the rotating member is rotatable while facing the recess. 4. The fuel cell according to claim 2, wherein the frictional force reducing means further comprises holding means for holding the rotating member so as to be extendable and contractable in a direction substantially perpendicular to the stacking direction of the cells. The fuel cell according to claim 4, wherein the holding unit holds the rotating member by an elastic member. 6. The fuel cell according to claim 2, wherein the frictional force reducing unit further includes a belt wound around the plurality of rotating members in common. The fuel cell according to claim 1, wherein the laminated component includes a spring box. The fuel cell according to any one of claims 1 to 7, wherein the outer member is fixed to both ends in the stacking direction of the stacked component. A preparation step of preparing a first base material in which a plurality of outer members for guiding a laminated part to a predetermined region are arranged at a predetermined interval;
A first laminating step of sequentially laminating the laminated component on the first base material while guiding the outer member,
Friction force reducing means for reducing a frictional force between the laminated component and the outer member in the lamination direction of the laminated component is provided on the surface of the outer member on the laminated component side. Manufacturing method of fuel cell. The frictional force reducing means includes a plurality of rotating members that are rotatable in the stacking direction,
The fuel cell manufacturing method according to claim 9, wherein the first stacking step is a step of stacking the stacked components while rotating the rotating member. The laminated component includes a recess facing the rotating member,
The method of manufacturing a fuel cell according to claim 10, wherein the first stacking step is a step of stacking the stacked components with the concave portion facing the rotating member. The frictional force reducing means further comprises a belt wound around the plurality of rotating members in common,
12. The method of manufacturing a fuel cell according to claim 10, wherein the first stacking step is a step of stacking the stacked components while driving the belt. A second laminating step of laminating the second base material on the laminated component after laminating the laminated component;
The fastening step of fastening the second base material to the outer member while applying a predetermined pressure to the first base material side with respect to the second base material. The manufacturing method of the fuel cell in any one. The outer member can be divided in the stacking direction,
The method of manufacturing a fuel cell according to claim 13, further comprising a separation step of separating the outer member above the laminated component after the fastening step.

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