JP2012133965A - Fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of the conventional fuel cell stacks in which the number of components is increased to obtain a structure for suppressing vibration of a laminate.SOLUTION: A fuel cell stack FS comprises: a laminate 1 formed by lamination of a plurality of rectangular plate-like unit cells FC; end plates 2 disposed on both end surfaces in the laminating direction of the cells of the laminate 1; and a pair of fastening plates 3 which, when four surfaces of the laminate 1 parallel to the laminating direction of the cells are referred to as first to fourth outer circumferential surfaces in the circumferential direction, are disposed on the second and the fourth outer circumferential surfaces. The both end plates 2 and each fastening plate 3 are coupled, and at least one of the pair of fastening plates 3 is provided with a rib 3B which is parallel to the laminating direction of the cells and presses the laminate 1. By this configuration, spring elements are mounted in the displacement direction of the laminate 1, and thereby the resonance frequency of the laminate 1 is increased and the resistance against vibration is enhanced without increasing the number of components.

Description

  The present invention relates to a fuel cell stack used as a power source for driving a vehicle, for example. More specifically, the present invention relates to a fuel cell stack including a laminated body formed by laminating a plurality of unit cells composed of a membrane electrode structure and a separator. It is about.

  Conventionally, as a fuel cell stack including a stack of unit cells, for example, there is one described in Patent Document 1. The fuel cell stack described in Patent Document 1 includes a stacked body in which a plurality of unit cells are stacked in a horizontal direction and is sandwiched between a pair of end plates at a predetermined pressure. To maintain the pressurized state of the laminate. The fuel cell stack has a structure in which intermediate plates are interposed at appropriate positions between the stacked bodies to support the stacked bodies at the positions of the respective intermediate plates, thereby reducing the resonance frequency between the support portions. The bending rigidity of the laminate was increased to increase the thickness.

JP 2010-27543 A

  However, since the conventional fuel cell stack as described above has a configuration in which a plurality of intermediate plates are interposed in the middle of the stack, the number of parts increases and the volume of the entire stack increases. It was a problem to solve such problems.

  The present invention has been made paying attention to the above-mentioned conventional problems, and has a structure in which spring elements are assembled in the displacement direction of the laminate without increasing the number of parts or the overall volume of the laminate. An object of the present invention is to provide a fuel cell stack capable of increasing the resonance frequency (natural frequency) of a laminate.

  The fuel cell stack of the present invention includes a laminate formed by laminating a plurality of rectangular plate-shaped unit cells, end plates disposed on both end faces of the laminate in the cell stacking direction, and four surfaces parallel to the cell stacking direction of the stack. Is provided with a pair of fastening plates arranged on the second and fourth outer peripheral surfaces when the first to fourth outer peripheral surfaces are defined in the circumferential direction.

  The fuel cell stack connects both end plates and the respective fastening plates, and at least one of the pair of fastening plates has a rib that is parallel to the cell stacking direction and presses the stack. The above-described configuration is used as means for solving the conventional problems.

  In the above configuration, the fastening plate and the laminate can be brought into contact with each other or in close proximity to each other through a very small gap to the extent that they come into contact with each other when vibration is input. Is more desirable.

  According to the fuel cell stack of the present invention, the resonance frequency of the multilayer body can be increased without increasing the number of parts and the volume of the entire multilayer body. As a result, vibration resistance can be improved, damage to components and power generation performance can be prevented, and man-hours and costs associated with manufacturing can be reduced.

It is the perspective view (A) explaining one Embodiment of the fuel cell stack of this invention, and the expanded sectional view (B) of a rib part. FIG. 2 is an exploded perspective view of the fuel cell stack shown in FIG. 1. It is a top view of the fuel cell stack shown in FIG. It is explanatory drawing which shows the principle of the spring element in the fuel cell stack shown in FIG. It is an expanded sectional view of the rib part in other embodiments of the fuel cell stack of the present invention. It is an expanded sectional side view of the rib part in other embodiment of the fuel cell stack of this invention. It is a top view in further another embodiment of the fuel cell stack of the present invention. It is a top view in further another embodiment of the fuel cell stack of the present invention. It is a perspective view in further another embodiment of the fuel cell stack of the present invention.

1 to 4 are diagrams illustrating an embodiment of a fuel cell stack according to the present invention.
A fuel cell stack FS shown in FIGS. 1A and 2 includes a stacked body 1 formed by stacking a plurality of rectangular plate-shaped unit cells FC, and both end surfaces of the stacked body 1 in the cell stacking direction (X direction in the figure). Current collector plates 5 and 5, end plates 2 and 2 disposed outside the current collector plate 5, a pair of fastening plates (one side is shown) 3, and another pair A pair of fastening plates (one side shown) 4 is provided. The materials of the end plate 2 and the fastening plates 3 and 4 are not particularly limited, but are preferably made of metal.

  The unit cell FC has a known structure in which a membrane electrode structure, which is a power generation element, is sandwiched between a pair of separators. As shown in FIG. 2, the unit cell FC has a rectangular plate shape and has a long side up and down. Laminated in the direction. The unit cell FC is basically a rectangular plate, but may have an approximate shape in which the fastening plates 3 and 4 can be assembled when the laminate 1 is formed.

  Both end plates 2 have a rectangular plate shape having substantially the same vertical and horizontal dimensions as the unit cell FC, and supply anode gas (hydrogen), cathode gas (air) and cooling fluid to the laminate 1. A manifold M and the like are formed. Both current collecting plates 5 correspond to the central portion (power generation portion) of the unit cell FC and have a connector portion 5A that penetrates the end plate 2.

  The fastening plates 3 of one set are arranged on the second and fourth outer peripheral surfaces, respectively, when the four surfaces parallel to the cell stacking direction of the laminate 1 are defined as the first to fourth outer peripheral surfaces in the circumferential direction. It is. Here, in FIG. 1A, the right side surface of the laminate 1 is the first outer peripheral surface, the upper surface is the second outer peripheral surface, the left side surface not shown in the figure is the third outer peripheral surface, and the bottom surface is the fourth. It is an outer peripheral surface.

  That is, the stacked body 1 in the illustrated example has rectangular plate-shaped unit cells FC stacked in the horizontal direction, and in this state, the stacked body 1 is easily displaced in a direction along the short side (vertical direction) of the unit cell FC. Therefore, the fuel cell stack FS is provided with the fastening plates 3 on at least the outer peripheral surface that is the long side of the unit cell FC, that is, the upper and lower second and fourth outer peripheral surfaces. In this embodiment, in order to further improve the vibration resistance, another fastening plate 4 is provided on the left and right first and third outer peripheral surfaces, which are the outer peripheral surfaces on the short side of the unit cell FC. It is configured.

  Each fastening plate 3, 4 is formed by bending flange-like attachment portions 3 A, 4 A at both ends, and each attachment portion 3 A, 4 A is attached to the outer surface (reverse side) of both end plates 2 by a plurality of bolts B. It is connected to the laminate side surface). Each of the fastening plates 3 and 4 includes ribs 3B and 4B that are parallel to the cell stacking direction and press the stack 1, and the ribs 3B and 4B have a beam structure that gives the stack 1 a spring element. Work.

  Here, in this type of fuel cell stack FS, when the stacked body 1 vibrates while being supported on both end plates 2 and 2 side, the displacement of the middle part of the stacked body 1 becomes the largest. Therefore, it is more preferable that the ribs 3B and 4B of the fastening plates 3 and 4 are provided at least in the center of the first to fourth outer peripheral surfaces which are the middle portions in the vibration direction of the laminate 1.

  As shown in FIG. 1B, the ribs 3B and 4B of the fastening plates 3 and 4 in this embodiment are formed into a groove shape by press work, and the central portions of the first to fourth outer peripheral surfaces are formed. It passes through the entire length of the stacked body 1 in the cell stacking direction. In particular, the pair of upper and lower fastening plates 3 form a gap with the laminate 1 as shown in FIG. 1B, and the bottom surfaces of the ribs 3B are in contact with the laminate 1. That is, there is no rib 3B, 4B in the end plate 2 portion. Thereby, the beam structure by rib 3B, 4B will act only on the range (shaded part) of the laminated body 1 shown in FIG.

  The fuel cell stack FS having the above-described configuration sandwiches the stacked body 1 and the current collector plate 5 with a predetermined pressure in the cell stacking direction by a pair of end plates 2 and 2, and both the end plates 2 and the fastening plates 3 and 3. 4 is connected to each other, so that the pressurized state of the laminate 1 is maintained.

  In the fuel cell stack FS, the ribs 3B and 4B of the respective fastening plates 3 and 4 form a beam structure in contact with the laminated body 1, and thus are provided on the second and fourth outer peripheral surfaces. With the rib 3B of the fastening plate 3, a spring element is assembled in the vibration direction of the laminate 1 (vertical direction in FIG. 1). That is, as shown in FIG. 4, a structure equivalent to a structure in which the laminated body 1 having the mass M is supported at a plurality of locations by the plurality of spring elements having the spring constant k. In particular, in the case of this embodiment, the ribs 3B continuous in the cell stacking direction provide a structure in which the spring element continuously operates in the entire length in the cell stacking direction, thereby supporting the stack 1.

  As described above, the fuel cell stack FS suppresses the displacement of the stacked body 1 by the pair of upper and lower fastening plates 3 and 3 having a simple structure particularly having the ribs 3B, so that the number of parts is not increased. The resonance frequency (natural frequency) can be increased. In addition, the fuel cell stack FS does not require any configuration in which a cushioning material is interposed between the laminate 1 and the fastening plate 3 or an intermediate portion of the laminate 1 is supported by a dedicated member. The resonance frequency can be increased in the structure supported on the both end plates 2 and 2 side without increasing the volume of the accommodating space.

  Since the fuel cell stack FS is connected to each manifold M of the end plate 2 with piping for supplying and discharging the reaction gas and cooling fluid, the fuel cell stack FS is supported on both end plates 2 and 2 as described above. For example, there is an advantage that vibration at the pipe connection portion can be suppressed.

  The fuel cell stack FS has improved vibration resistance as the resonance frequency of the laminate 1 increases, and can prevent damage to components and decrease in power generation performance due to vibration. In addition, it will reduce man-hours and costs related to manufacturing.

  Further, the fuel cell stack FS is a functional component that maintains the pressurized state of the stacked body 1 because another pair of fastening plates 4 are disposed on the first and third outer peripheral surfaces of the left and right of the stacked body 1. The end plate 2 and the fastening plates 3 and 4 can form a case-integrated structure. Thereby, it becomes possible to abolish another special case, and it can contribute to further reduction of the number of parts and further reduction of manufacturing cost.

  Furthermore, in the fuel cell stack FS, the fastening plate 3 is configured to include the rib 3B at a position corresponding to at least the central portion of the outer peripheral surface of the multilayer body 1, thereby suppressing the vibration of the multilayer body 1 to the minimum. With this configuration, the antinode of the resonance primary mode of the laminate 1 can be suppressed.

  Furthermore, the fuel cell stack FS is very easy to form the fastening plates 3 and 4 having the ribs 3B and 4B without increasing the weight of the parts by forming the ribs 3B and 4B of the fastening plates 3 and 4 by press working. Can be manufactured.

  Furthermore, the fuel cell stack FS can more reliably suppress the vibration of the stacked body 1 by providing the ribs 3B and 4B of the fastening plates 3 and 4 over the entire length of the stacked body 1 in the cell stacking direction. The rigidity of 3 and 4 can also be increased.

  Furthermore, the fuel cell stack FS can be mounted on the vehicle as a power source for driving the vehicle. In this case, it is desirable that the natural frequency (resonance frequency) in the laminate 1 is 60 Hz or more. Thereby, the resonance phenomenon of the laminated body 1 by external forces, such as a vibration peculiar to a vehicle, can fully be suppressed.

  In the above embodiment, the case where the rib 3B of the fastening plate 3 and the laminated body 1 are brought into contact with each other has been described. However, the rib 3B and the laminated body 1 have a very small gap to the extent that they come into contact with each other when vibration is input. And may be brought close to each other. In this case, the laminate 1 and the rib 3B come into contact with the input of vibration, and the vibration of the laminate 1 is suppressed by the rib 3B forming the beam structure.

  FIG. 5 is a diagram illustrating another embodiment of the fuel cell stack of the present invention. In the following embodiments, the same components as those in the previous embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the illustrated fuel cell stack FS, a pair of fastening plates 3 are arranged on the upper and lower second and fourth outer peripheral surfaces of the laminate 1, and a rib 3B extending over the entire length in the cell stacking direction is provided at the center of the fastening plate 3. It is formed. And the rib 3B in the fastening plate 3 has the slit S along the centerline.

  The fuel cell stack FS can obtain the same operations and effects as those of the previous embodiment, and the slit 3 is provided along the center line of the rib 3, so that the rib 3B is bisected in the cross section, It becomes possible to act as two springs (cantilever beams) whose slit S side is a free end. Thereby, the vibration suppression effect of the laminated body 1 can be improved more.

  FIG. 6 is a diagram for explaining still another embodiment of the fuel cell stack of the present invention. The illustrated fuel cell stack FS has the same configuration as that shown in FIG. 5, and the fastening plate 3 is bent and connected to the end plate 2, so that the rib 3 </ b> B is pressed against the laminate 1. It is assumed that

  The fuel cell stack FS can obtain the same operation and effect as those of the previous embodiment, and generates a pressing load (arrow F in the figure) of the rib 3B of the fastening plate 3, so that the rib 3B and the laminated body are generated. 1 can be ensured, and the vibration suppressing effect by the beam structure of the rib 3B can be further enhanced.

  FIG. 7 is a diagram illustrating still another embodiment of the fuel cell stack of the present invention. As described above, in the fuel cell stack FS, it is only necessary that the fastening plate 3 includes the rib 3B at a position corresponding to at least the central portion of the outer peripheral surface of the stacked body 1. Therefore, the fuel cell stack FS shown in FIG. 7 has a configuration in which a rib 3B is provided only at the center of the pair of fastening plates 3 on the upper and lower sides of vibration.

  Even in the above fuel cell stack FS, the same operations and effects as those of the previous embodiments can be obtained, and the resonance of the stacked body 1 can be achieved with the minimum necessary configuration for suppressing the vibration of the stacked body 1. The belly of the primary mode can be suppressed.

  8 and 9 are diagrams for explaining still another embodiment of the fuel cell stack of the present invention. Here, the fuel cell stack of the present invention can be configured such that the ribs of the fastening plate are provided at a plurality of locations as a more preferred embodiment.

  That is, the fuel cell stack FS shown in FIG. 8 has a configuration in which ribs 3B are provided at three locations along the center line in the cell stacking direction passing through the center of the pair of fastening plates 3 on the upper and lower sides of vibration. It is. Further, in the fuel cell stack FS shown in FIG. 9, the pair of upper and lower fastening plates 3 are also parallel to each other at the center line in the cell stacking direction passing through the center portion and at three positions on both sides thereof, and the stack 1 In this configuration, three ribs 3B are provided over the entire length in the cell stacking direction.

  The fuel cell stack FS can obtain the same operations and effects as those of the previous embodiments, and can arbitrarily set the load point of the rib 3B functioning as a beam structure. In other words, the fuel cell stack FS has, for example, the size and position of the rib 3B, the cross-sectional shape, and the stack 1 according to various conditions such as the vibration characteristics of the stack 1 and the thicknesses and materials of the fastening plates 3 and 4. By selecting the contact area or the like, the spring constant k due to the beam structure of the rib 3B can be freely set.

  As described above, the fuel cell stack FS can freely set the spring constant k of the beam structure (rib 3B) by selecting the form of the rib 3B according to the location where the amplitude of the stacked body 1 is desired to be suppressed. The vibration of the body 1 can be efficiently suppressed.

  The fuel cell stack FS of the present invention includes, as an essential requirement, a fastening plate 3 and 3 on the second and fourth outer peripheral surfaces of the first to fourth outer peripheral surfaces of the laminate 1 and a pair of fastenings. The rib 3B is provided on at least one of the plates 3 and 3. Therefore, the fuel cell stack FS may be configured such that one fastening plate 3 is a flat plate without ribs, or has no fastening plate on the left and right first and third outer peripheral surfaces as shown in FIG. it can.

  As a more preferred embodiment, the fuel cell stack of the present invention can have a configuration in which an insulating coating is applied to at least the surface of the fastening plates 3 and 4 on the side of the laminate. As a result, the fuel cell stack FS can secure internal and external insulation without inserting an insulating member between the fastening plates 3 and 4 and the laminate 1, further reducing the number of parts, This can contribute to further reduction in manufacturing man-hours and costs.

  The configuration of the fuel cell stack of the present invention is not limited to the above embodiments, and the form, number, material, and the like of each component can be changed as appropriate without departing from the spirit of the present invention. It is.

  Further, in each of the above embodiments, the stacked body 1 formed by stacking rectangular plate-shaped unit cells FC is illustrated. In this case, although depending on the ratio of the lengths of the long side and the short side, usually, vibration is likely to occur in the direction along the short side of the unit cell (vertical direction in FIG. 1), so at least the vibration direction. The structure which provided the fastening board in the upper and lower 2nd and 4th outer peripheral surfaces and provided the rib 3B in the fastening board 3 was demonstrated.

  Since the fuel battery cell of the present invention is intended for a laminate formed by stacking rectangular plate unit cells, the unit cell may be a square plate. In this case, vibration may occur in the direction along the second and fourth outer peripheral surfaces and in the direction along the first and third outer peripheral surfaces. Therefore, when the unit cell has a square plate shape, it is more desirable to arrange a fastening plate on the first to fourth outer peripheral surfaces and to provide a rib on each fastening plate. Vibration can be effectively suppressed.

FC unit cell FS Fuel cell stack 1 Stack 2 End plate 3 Fastening plate 3B Rib 4 Fastening plate 4B Rib

Claims (11)

A laminate formed by laminating a plurality of rectangular plate unit cells;
End plates arranged on both end faces in the cell stacking direction of the laminate,
The laminate includes a pair of fastening plates arranged on the second and fourth outer peripheral surfaces when the four surfaces parallel to the cell stacking direction of the laminate are defined as the first to fourth outer peripheral surfaces in the circumferential direction. Connect the fastening plates respectively.
At least one of the pair of fastening plates includes a rib that is parallel to the cell stacking direction and presses the stack.   The unit cell has a rectangular plate shape, and the second and fourth outer peripheral surfaces of the laminate on which the fastening plate is disposed are outer peripheral surfaces that are the long sides of the unit cell. The fuel cell stack described.   Another pair of fastening plates connected to both end plates are disposed on the first and third outer peripheral surfaces of the laminate, and at least one of the other pair of fastening plates is provided with the rib. The fuel cell stack according to claim 1 or 2, characterized in that:   The fuel cell stack according to any one of claims 1 to 3, wherein the fastening plate is bent and connected to the end plate to press the rib against the laminated body.   The fuel cell stack according to any one of claims 1 to 4, wherein the fastening plate includes a rib at a position corresponding to at least a central portion of the outer peripheral surface of the laminate.   6. The fuel cell stack according to any one of 1 to 5, wherein a rib of the fastening plate is formed by press working.   The fuel cell stack according to claim 5 or 6, wherein ribs of the fastening plate are provided at a plurality of locations.   The fuel cell stack according to any one of claims 5 to 7, wherein a rib of the fastening plate is provided over the entire length in the cell stacking direction of the stacked body.   The fuel cell stack according to any one of claims 6 to 8, wherein a rib of the fastening plate has a slit along a center line thereof.   The fuel cell stack according to any one of claims 1 to 9, wherein an insulating coating is applied to at least a surface of the fastening plate on the side of the laminated body.   The fuel cell stack according to any one of claims 1 to 10, wherein the fuel cell stack is mounted on a vehicle as a power source for driving a vehicle, and the natural frequency of the laminate is 60 Hz or more.

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