Cell stack support structure for fuel cells

Abstract

To provide a cell stack support structure for fuel cell which is capable of maintaining at least G-tolerance and suppressing accumulation of hydrogen in a fuel cell case with an electrical insulation state secured.SOLUTION: A cell stack support structure 10 for fuel cell is provided with a cell stack 16, a buffer material 34, and a mesh tube 38. The buffer material 34 has insulation property and is filled in a gap 32 between the cell stack 16 and a fuel cell case 12. Thus, G-tolerance can be maintained in the cell stack 16, and the buffer material 34 having insulation property can be maintain an electric insulation state in the cell stack 16. The mesh tube 38 can ventilate hydrogen and is connected to a gap part 36 for ventilation that can be communicated with an outside the fuel cell case 12. Thus, hydrogen leaked from the cell stack 16 can be discharged to the outside of the fuel cell case 12 via the mesh tube 38 and the gap part 36, and accumulation of hydrogen inside the fuel cell case 12 is suppressed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a cell stack support structure for a fuel cell.

Background Art

[0002] In Patent Document 1 below, a thin plate fastening (tension) plate is bridged between a pair of end plates disposed at both ends in the stacking direction of a laminate constituting a fuel cell, above and below the laminate, and a resin buffer material is provided inside the thin plate fastening plate.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, fuel cell systems are spreading to a wide variety of mobilities, not limited to automobiles, and accordingly, the required G tolerance performance value is increasing. On the other hand, since a cell stack for a fuel cell is a high-voltage component, it is necessary to maintain an electrical insulation state by stacking 300 or more cells and compressing and fastening them in a floating state inside a fuel cell case. Further, there is a phenomenon of hydrogen permeation from the cell stack, and it is necessary to maintain ventilation performance between the cell stack and the fuel cell case from the perspective of hydrogen safety regulations.

[0005] In consideration of the above facts, an object of the present invention is to provide a cell stack support structure for a fuel cell that can suppress the accumulation of hydrogen in a fuel cell case while maintaining at least G tolerance performance and ensuring an electrical insulation state.

Means for Solving the Problems

[0006] The cell stack support structure for a fuel cell according to claim 1 comprises a cell stack supported on a fuel cell case with a gap between it and the fuel cell case, a cushioning material filled in the gap which is insulating and shock-absorbing, and a plurality of mesh tubes provided on the surface of the cell stack that are connected to a ventilation gap which allows hydrogen ventilation and communicates with the outside of the fuel cell case, wherein the distance Y between adjacent mesh tubes is set to be smaller than the outer diameter X of the mesh tubes.

[0007] The cell stack support structure for a fuel cell according to claim 1 comprises a cell stack, a cushioning material, and a mesh tube. The cell stack is supported against the fuel cell case with a gap between it and the fuel cell case. The cushioning material is filled into the gap between the cell stack and the fuel cell case, and is insulating and capable of absorbing shock.

[0008] In this way, by providing a cushioning material between the cell stack and the fuel cell case, the shock input to the cell stack can be absorbed by the cushioning material, making it possible to maintain the G-force resistance of the cell stack. Furthermore, because the cushioning material has insulating properties, it is possible to maintain an electrically isolated state in the cell stack, thereby ensuring the safety of high-voltage components.

[0009] Furthermore, in this invention, multiple mesh tubes are provided on the surface of the cell stack. These mesh tubes are capable of hydrogen ventilation and are connected to ventilation gaps that communicate with the outside of the fuel cell case. Therefore, hydrogen leaking from the cell stack flows into the mesh tubes and can be discharged to the outside of the fuel cell case through the ventilation gaps. As a result, in this invention, it is possible to suppress the accumulation of hydrogen inside the fuel cell case.

[0010] By the way, as a comparative example, when the distance Y between adjacent mesh tubes is wider than the outer diameter dimension X of the mesh tube (Y > X), hydrogen leaked from the cell stack may flow out to the buffer material side through the space between the adjacent mesh tubes arranged adjacent to each other and accumulate in the buffer material.

[0011] On the other hand, in the present invention, the distance Y between adjacent mesh tubes is set to be smaller than the outer diameter dimension X of the mesh tube (Y < X). Therefore, the distance between adjacent mesh tubes arranged adjacent to each other can be made narrower than in the comparative example.

[0012] Thereby, it becomes possible to suppress the outflow of hydrogen leaked from the cell stack to the buffer material side. Therefore, in the present invention, it is possible to prevent the accumulation of hydrogen in the buffer material while suppressing the cost, and it is possible to comply with the hydrogen safety regulations.

[0013] Here, the "distance Y between mesh tubes" is the gap provided between adjacent mesh tubes when the cell stack is viewed from the outside.

Effect of the Invention

[0014] As described above, the fuel cell stack support structure according to the present invention can suppress the accumulation of hydrogen in the fuel cell case while maintaining at least the G resistance performance and ensuring the electrical insulation state.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic cross-sectional view when the fuel cell case constituting a part of the fuel cell stack support structure according to the present embodiment is cut along the longitudinal direction of the fuel cell case. [Figure 2] (A) is a schematic cross-sectional view when cut along the line A-A' shown in FIG. 1, and (B) is a partially enlarged cross-sectional view obtained by enlarging a part of FIG. 2(A). [Figure 3]This is a cross-sectional view corresponding to Figure 1, showing a modified example of the cell stack support structure for a fuel cell according to this embodiment. [Modes for carrying out the invention]

[0016] The following description will explain, with reference to the drawings, a cell stack support structure for a fuel cell according to an embodiment of the present invention.

[0017] (Configuration of the cell stack support structure for fuel cells) First, the configuration of the cell stack support structure for fuel cells according to an embodiment of the present invention will be described.

[0018] Figure 1 shows a schematic cross-sectional view of a fuel cell case 12 (described later), which constitutes a part of the fuel cell cell stack support structure 10 according to this embodiment, when the fuel cell case 12 is cut along its longitudinal direction. As shown in Figure 1, in this embodiment, the fuel cell cell stack support structure 10 is equipped with a cell stack 16, and this cell stack 16 corresponds to a so-called fuel cell.

[0019] The cell stack 16 is housed within a fuel cell case 12 that is roughly box-shaped, and is configured such that multiple plate-shaped fuel cell cells 14 are stacked along the longitudinal direction of the fuel cell case 12. End plates 18 and 20 are provided at both ends of the cell stack 16 in the longitudinal direction. In this embodiment, for example, the end plate 18 is set to be approximately the same size as the external dimensions of the cell 14. On the other hand, the end plate 20 is set to be slightly larger than the external dimensions of the cell 14.

[0020] A rectangular hole 22 is formed in the side wall 12A of the fuel cell case 12 facing the end plate 18. From the inner edge of the rectangular hole 22, for example, a rectangular rib 24 is erected toward the outside of the fuel cell case 12, and a ventilation membrane 26 is provided on the tip surface of the rectangular rib 24. The inside of the fuel cell case 12 can communicate with the outside air through this ventilation membrane 26.

[0021] Support members 28 and 30 are provided above and below the rectangular hole 22, respectively. The support members 28 and 30 are, for example, square tubular in shape and are arranged substantially horizontally within the fuel cell case 12. One end of each of the support members 28 and 30 is fastened and fixed to the side wall 12A of the fuel cell case 12, and the other end of each of the support members 28 and 30 is fastened and fixed to the end plate 18 of the cell stack 16.

[0022] In this way, with the cell stack 16 supported by the support member 28, the cell stack 16 is set to be in a floating state with respect to the fuel cell case 12 as shown in Fig. 2(A). Clearances 32 are provided between the upper side, lower side, and lateral side of the cell stack 16 and the fuel cell case 12, respectively, and buffer materials 34 are filled in the clearances 32. Note that Fig. 2(A) is a schematic cross-sectional view when cut along the A-A' line shown in Fig. 1.

[0023] The buffer material 34 is formed of a foamed resin, rubber, etc., has insulating properties, and can absorb the impact input to the cell stack 16. As shown in Fig. 1, no buffer material 34 is provided between the rectangular hole 22 and the end plate 18, and it is a ventilation void portion 36. The wall portion constituting the void portion 36 is formed by the end face 34A of the buffer material 34 in the void portion 36.

[0024] Here, in the present embodiment, on the surface 16A of the cell stack 16, mesh tubes 38 and 40 are adhered along the longitudinal direction of the cell stack 16 via double-sided tape, adhesive, etc. One end of the mesh tube 38 is attached to the upper end portion of the end plate 20, and the other end of the mesh tube 38 is disposed within the void portion 36. Also, one end of the mesh tube 40 is disposed within the void portion 36, and the other end of the mesh tube 40 is attached to the lower end portion of the end plate 20. Nothing is filled in the mesh tubes 38 and 40, and the inside of the mesh tubes 38 and 40 and the void portion 36 communicate with each other.

[0025] Also, as shown in FIG. 2(A), a plurality of mesh tubes 38 are provided, for example, along the width direction of the cell stack 16. Among these plurality of mesh tubes 38, as shown in FIG. 2(B), the interval Y between adjacent mesh tubes 38 arranged adjacent to each other is set to be smaller than the outer diameter dimension X of the mesh tube 38 (Y < X).

[0026] (Function and Effect of Fuel Cell) Next, the function and effect of the fuel cell to which the cell stack support structure for a fuel cell according to the embodiment of the present invention is applied will be described.

[0027] As shown in FIG. 1, in the present embodiment, the cell stack support structure 10 for a fuel cell includes a cell stack 16, a cushioning material 34, and a mesh tube 38. The cell stack 16 is supported with respect to the fuel cell case 12 with a gap 32 provided between the support members 28 and 30 and the fuel cell case 12. Further, the cushioning material 34 is filled in the gap 32 provided between the upper side, the lower side, and the side of the cell stack 16 and the fuel cell case 12, respectively. Furthermore, the cushioning material 34 has insulating properties and is capable of absorbing shock.

[0028] In this way, in the present embodiment, by providing the cushioning material 34 between the cell stack 16 and the fuel cell case 12, the shock input to the cell stack 16 can be absorbed by the cushioning material 34. As a result, in the present embodiment, it is possible to maintain the G - tolerance performance in the cell stack 16. Also, in the present embodiment, since the cushioning material 34 has insulating properties, it is possible to maintain an electrically insulated state in the cell stack 16, and safety in high - voltage components can be ensured.

[0029] Also, in the present embodiment, as shown in FIG. 2(A), a plurality of mesh tubes 38 and 40 are provided on the surface of the cell stack 16 along the longitudinal direction of the cell stack 16. The mesh tubes 38 and 40 are capable of hydrogen ventilation and are connected to a ventilation void portion 36 that can communicate with the outside of the fuel cell case 12. The void portion 36 communicates with the rectangular hole 22 and can communicate with the outside air through a ventilation film 26 provided on the tip surface of a rectangular rib 24 standing upright from the rectangular hole 22.

[0030] Here, the gas in the mesh tubes 38 and 40 flows (diffuses) through the mesh tubes 38 and 40 with the pressure difference, temperature difference, and concentration difference as the driving forces. On the other hand, since the void portion 36 communicates with the outside air, the hydrogen concentration is always at a low level. Therefore, in the present embodiment, when hydrogen leaked from the cell stack 16 flows into the mesh tube 38, it can be discharged outside the fuel cell case 12 through the void portion 36 with a low hydrogen concentration. Thereby, in the present embodiment, it becomes possible to suppress the accumulation of hydrogen in the fuel cell case 12.

[0031] Furthermore, the pressure difference or temperature difference between the inside and outside of the fuel cell case 12 always occurs during the operation of the fuel cell system. The driving force for flowing the gas due to this pressure difference or temperature difference is even greater than the driving force due to the concentration difference. Therefore, during the operation of the fuel cell system, it becomes possible to further improve the hydrogen ventilation performance in the fuel cell case 12. And since the ventilation volume in the mesh tubes 38 and 40 is larger than the amount of permeated hydrogen flowing into the mesh tubes 38 and 40, there is almost no possibility that hydrogen will stay in the mesh tubes 38 and 40.

[0032] On the other hand, in the present embodiment, as shown in FIG. 2(B), the interval Y between adjacent mesh tubes 38 is set to be smaller than the outer diameter dimension X of the mesh tube 38 (Y < X). Although not shown in FIG. 2(B), the mesh tube 40 is the same as the mesh tube 38.

[0033] As a comparative example, although not shown in the drawings, when the distance Y between adjacent mesh tubes 38 is wider than the outer diameter dimension X of the mesh tube 38 (Y>X), hydrogen leaked from the cell stack 16 may flow out to the side of the buffer material 34 through the space between the adjacent mesh tubes 38 arranged adjacent to each other and accumulate in the buffer material 34.

[0034] In contrast, in the present embodiment, as described above, the distance Y between adjacent mesh tubes 38 arranged adjacent to each other is set to be smaller than the outer diameter dimension X of the mesh tube 38 (Y<X). Therefore, in the present embodiment, the distance between adjacent mesh tubes 38 arranged adjacent to each other can be made narrower than in the comparative example.

[0035] As a result, it becomes possible to suppress the outflow of hydrogen leaked from the cell stack 16 to the side of the buffer material 34. Therefore, in the present embodiment, it is possible to prevent the accumulation of hydrogen in the buffer material 34 while suppressing costs, and comply with hydrogen safety regulations.

[0036] From the above, in the cell stack 16 in the present embodiment, it is possible to suppress the accumulation of hydrogen in the fuel cell case 12 while maintaining at least the G resistance performance and ensuring the electrical insulation state.

[0037] Further, in the present embodiment, since the buffer material 34 is filled above, below, and on the side of the cell stack 16, the G resistance performance is dramatically improved as compared with the prior art of Patent Document 1 described in the background art section. Furthermore, in the present embodiment, since there is no change in the basic structure of the fuel cell case 12 and the cell stack 16, problems such as weight increase and size increase do not occur.

[0038] In addition, in the present embodiment, although an example in which mesh tubes 38 and 40 are provided between the cell stack 16 and the buffer material 34 as shown in FIG. 1 has been described, the present invention is not limited thereto.

[0039] For example, as shown in Figure 3, mesh tubes 42 and 44 may be provided not only between the cell stack 16 and the buffer material 34, but also between the buffer material 34 and the fuel cell case 12. Under severe G-force conditions, it becomes necessary to increase the thickness of the buffer material 34. In this case, if hydrogen that has permeated into the buffer material 34 goes to the back of the buffer material 34, it may not be possible to recover the hydrogen using only the mesh tubes 38 and 40 provided on the surface of the cell stack 16.

[0040] However, by providing mesh tubes 38 and 40 between the cell stack 16 and the buffer material 34, and mesh tubes 42 and 44 between the buffer material 34 and the fuel cell case 12, hydrogen that flows out to the buffer material 34 side through the adjacent mesh tubes 38 (or mesh tube 40) flows into the mesh tube 42 (or mesh tube 44). This allows it to be discharged to the outside of the fuel cell case 12 through the gap 36. Therefore, in this embodiment, it is possible to prevent the accumulation of hydrogen in the buffer material 34, and further suppress the accumulation of hydrogen in the fuel cell case 12.

[0041] Although one embodiment of the present invention has been described above, the present invention is not limited to these embodiments, and various modifications may be used in appropriate combinations with one embodiment, and of course, the invention can be implemented in various forms without departing from the spirit of the present invention. [Explanation of Symbols]

[0042] 10. Cell stack support structure for fuel cells 12 Fuel Cell Case (Case) 16-cell stack 16A surface 32 gaps 34 Cushioning material 36 Cavity 38 Mesh Tubes 40 Mesh Tubes 42 Mesh Tubes 44 Mesh Tubes

Claims

[Claim 1] A cell stack supported with respect to the fuel cell case with a gap between it and the fuel cell case, A cushioning material is filled into the gap, has insulating properties, and is capable of absorbing shock. Multiple mesh tubes are provided on the surface of the cell stack, which are connected to ventilation gaps that allow hydrogen ventilation and communicate with the outside of the fuel cell case, Equipped with, A cell stack support structure for a fuel cell, wherein the distance Y between adjacent mesh tubes is set to be smaller than the outer diameter X of the mesh tube.

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