JP2009070674A - Fuel cell stack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell stack in which even if an impact force is applied from the vertical direction to the laminating direction of a plurality of unit cells, position shifting in the vertical direction to the lamination direction of the unit cells is suppressed. <P>SOLUTION: The fuel cell stack 100 is provided with a laminate in which a plurality of unit cells 40 are laminated and a plurality of external restraining members 60, 70, 80, 90 which are external restraining members to restrict position shifting of the unit cells 40 to the vertical direction to the lamination direction of the plurality of unit cells 40 in the laminate and are fixed to the laminate in a state contacting throughout the lamination direction on the faces parallel to the lamination direction of the laminate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell stack.

  A fuel cell that generates electricity by an electrochemical reaction between a fuel gas (for example, hydrogen) and an oxidant gas (for example, oxygen) has attracted attention as an energy source. This fuel cell includes a fuel cell stack including a stacked body in which a plurality of single cells are stacked.

  In such fuel cell stacks, in general, contact resistance between and within single cells is reduced, and leakage of fluid (fuel gas, oxidant gas, cooling water) flowing in the fuel cell stack is prevented. For example, a fastening load is applied in the stacking direction of the single cells and the fastening is performed by the fastening member.

  In such a fuel cell stack, when an impact force is applied from the direction perpendicular to the stacking direction of the single cells, and the single cell is displaced in the direction perpendicular to the stacking direction by the impact force, The battery stack may be damaged. Therefore, conventionally, various techniques have been proposed for the fuel cell stack in order to suppress displacement in the direction perpendicular to the stacking direction of the single cells, that is, to externally constrain a plurality of single cells. For example, in Patent Document 1 below, notches are provided at the four corners of a separate plate that constitutes a single cell, and fastening studs are arranged so as to be in contact with the respective notches, whereby a plurality of single cells are externally restrained. However, it is described that the fuel cell stack is configured by fastening the fastening plate.

JP 2003-197250 A Japanese Patent Laying-Open No. 2005-100807 JP-A-10-106610 JP 2003-86232 A

  By the way, in the technique described in the above-mentioned Patent Document 1, a dimensional error in manufacturing is inevitably generated in a plurality of separate plates and fastening plates. Further, when a plurality of single cells are stacked, a positional shift between the single cells is inevitably generated. The position of the fastening stud on the fastening plate is defined in advance. Therefore, in order to manufacture the fuel cell stack described in Patent Document 1, the fuel cell stack is provided on the separate plate in consideration of the above-described dimensional error, positional deviation when stacking single cells, and assembling property. It is inevitably necessary to provide a gap between the notch and the fastening stud.

  However, in the technique described in the above-mentioned Patent Document 1, no consideration is given to such a gap, and a fastening stud is arranged so as to be in contact with the notches provided at the four corners of the separate plate. It was actually difficult to construct a fuel cell stack. Further, in the technique described in Patent Document 1, when the above-described gap is provided, each single cell may be displaced by the amount of the gap, and a sufficient external constraint effect cannot be obtained. Cases could arise.

  The present invention has been made in order to solve the above-described problem, and in a fuel cell stack, even when an impact force is applied from a direction perpendicular to the stacking direction of a plurality of single cells, the single cell An object is to suppress a positional shift in a direction perpendicular to the stacking direction of the layers.

  The present invention can be realized as the following forms or application examples in order to solve at least a part of the above-described problems.

  [Application Example 1] A fuel cell stack, in which a plurality of single cells are stacked, and in the stacked body, the single cells are displaced in a direction perpendicular to the stacking direction of the plurality of single cells. And a plurality of fixed members fixed to the laminate in a state of being in contact with a surface parallel to the lamination direction of the laminate over the entire lamination direction. And a fuel cell stack comprising an external restraining member.

  In the fuel cell stack of Application Example 1, a plurality of external restraining members are in contact with a surface parallel to the stacking direction of the laminate over the entire stacking direction, that is, the plurality of external restraining members and the above-described It fixes to the said laminated body in the state without a clearance gap between laminated bodies. Therefore, in the fuel cell stack, even when an impact force is applied from the direction perpendicular to the stacking direction of the plurality of single cells, it is possible to suppress positional deviation in the direction perpendicular to the stacking direction of the single cells. it can.

  [Application Example 2] The fuel cell stack according to Application Example 1, wherein a plurality of fitting recesses respectively fitting with the plurality of external restraining members are provided on a surface parallel to the stacking direction of the stacked body. A fuel cell stack is formed.

  According to this application example, the positioning of the external restraining member in the laminate can be easily performed.

  [Application Example 3] The fuel cell stack according to Application Example 2, wherein the fitting recess is fitted with the external restraint member, and the external restraint member is perpendicular to the stacking direction of the laminate. A fuel cell stack having an inner wall surface that acts when dispersed in at least two directions different from the direction of the external force when an external force is applied to the battery.

  According to this application example, when fixing a plurality of external restraining members to the laminate, by applying an external force in one direction for one external restraining member, the external restraining member is housed in the fitting recess, A plurality of external restraining members can be brought into contact with each single cell relatively easily.

  Application Example 4 The fuel cell stack according to Application Example 1, wherein the stacked body has a ridge parallel to the stacking direction, and the external restraining member is fitted to the ridge. A fuel cell stack comprising a fitting recess.

  Also according to this application example, it is possible to easily position the external restraining member in the laminate.

  Application Example 5 The fuel cell stack according to any one of Application Examples 1 to 4, wherein the plurality of external restraining members are fastened to the stacked body using an annular elastic member. Fixed to the fuel cell stack.

  According to this application example, a plurality of external restraining members can be fixed to the laminate with a substantially uniform force. The number of the annular elastic members can be arbitrarily set.

  [Application Example 6] The fuel cell stack according to Application Example 5, further comprising an adjusting unit for adjusting the tightening force of the plurality of external restraining members by the annular elastic member.

  According to this application example, it is possible to improve convenience when a plurality of external restraining members are fastened to the laminate by the elastic member.

  Application Example 7 The fuel cell stack according to any one of Application Examples 1 to 6, wherein the external restraint member is made of metal, and an insulating member is provided between the external restraint member and the laminate. Is a fuel cell stack.

  According to this application example, it is possible to secure the rigidity of the external restraint member and to secure insulation between the external restraint member and the plurality of single cells. In this application example, as an aspect in which the insulating member is interposed between the external restraining member and the laminated body, any aspect that can ensure insulation between the external restraining member and the laminated body may be used. It is not restricted to the aspect which clamps an insulating member with a member and a laminated body. For example, the insulating member may be integrally formed on the surface of the external restraining member, or the insulating member may be integrally formed on the surface of the laminate.

  The present invention can also be configured by appropriately combining the various features described above. Further, the present invention can be configured as an invention of a method for manufacturing a fuel cell stack in addition to the above-described configuration as a fuel cell stack.

Hereinafter, embodiments of the present invention will be described based on examples.
A. First embodiment:
A1. Fuel cell stack configuration:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as a first embodiment of the present invention. The fuel cell stack 100 generally has a stack structure in which a plurality of single cells are stacked. Each single cell is configured by sandwiching a membrane electrode assembly formed by joining an anode and a cathode on both sides of an electrolyte membrane having proton conductivity, with a separator. In this example, a solid polymer membrane was used as the electrolyte membrane. Another electrolyte such as a solid oxide may be used as the electrolyte. The number of membrane electrode assemblies stacked in the fuel cell stack 100 can be arbitrarily set according to the output required for the fuel cell stack 100.

  As shown in the figure, the fuel cell stack 100 is laminated from one end in the order of an end plate 10a, an insulating plate 20a, a current collecting plate 30a, a plurality of single cells 40, a current collecting plate 30b, an insulating plate 20b, and an end plate 10b. It is constituted by. In the present embodiment, each of these has a horizontally long and substantially rectangular shape. The plurality of unit cells 40 stacked corresponds to the stacked body in the present invention.

  Although not shown, a supply manifold (hydrogen supply manifold, air supply) for distributing and supplying hydrogen, air, and cooling water to each single cell 40 inside the fuel cell stack 100 is omitted. Manifold, cooling water supply manifold), anode off-gas and cathode off-gas discharged from the anode and cathode of each single cell 40, and a discharge manifold (anode) for collecting cooling water and discharging it outside the fuel cell stack 100 Off-gas discharge manifold, cathode off-gas discharge manifold, cooling water discharge manifold).

  The end plates 10a and 10b are made of metal such as steel in order to ensure rigidity. The insulating plates 20a and 20b are formed of an insulating member such as rubber or resin. The current collecting plates 30a and 30b are formed of dense carbon, a gas impermeable conductive member such as a copper plate. The current collector plates 30a and 30b are provided with output terminals 32a and 32b, respectively, so that the power generated by the fuel cell stack 100 can be output.

A2. Fastening structure of fuel cell stack and external restraint structure of a plurality of single cells:
In the fuel cell stack 100, the plurality of single cells 40 and the like have a stack structure in order to suppress a decrease in battery performance due to an increase in contact resistance in any part of the stack structure or to prevent gas leakage. Fastened with a predetermined fastening load applied in the stacking direction. In addition, in the fuel cell stack 100 of the present embodiment, external restraint is performed in order to prevent displacement in the vertical direction with respect to the stacking direction of the plurality of single cells 40. Hereinafter, the fastening structure of the fuel cell stack 100 and the external restraint structure of the plurality of single cells 40 (stacked body) in the present embodiment will be described.

  First, the fastening structure of the fuel cell stack 100 will be described. FIG. 2 is an explanatory view showing a cross section AA in FIG. As can be seen from FIGS. 1 and 2, in this embodiment, the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the cutouts (for example, FIG. The notch 45) shown in a) is formed. And these are arrange | positioning the bolt 52 to the both ends of each fastening member 50, arrange | positioning the square-column-shaped fastening member 50 in the four corners of the end plates 10a and 10b, respectively, and applying fastening load in the lamination direction of a stack structure. Are fastened by being fixed to the four corners of the end plates 10a and 10b, respectively.

  In addition, between each notch part 45 and the fastening member 50, in consideration of the dimensional error on manufacture of the single cell 40, the position shift at the time of laminating | stacking the several single cell 40, and an assembly | attachment property, it is dimension. A gap d is provided. In addition, the above-described fastening load in the fuel cell stack 100 is obtained by inserting a spacer between the end plate 10a and the insulating plate 20a, or between the end plate 10b and the insulating plate 20b, and the thickness of the spacer. Or by adjusting the thickness of the insulating plates 20a and 20b. Further, since the length of the fastening member 50 is defined in advance, the length of the fuel cell stack 100 in the stacking direction is constant regardless of the magnitude of the fastening load described above.

  Next, the external constraint structure of the plurality of single cells 40 will be described. As shown in FIGS. 2A and 2B, in this embodiment, the illustrated upper side surface, lower side surface, left side surface, right side surface of the plurality of unit cells 40 (stacked body), that is, In the center part of the upper long side, the lower long side, the left short side, and the right short side of each unit cell 40, a fitting having a triangular shape that fits with the external restraining members 60, 70, 80, 90, respectively. Joint recesses 46, 47, 48, and 49 are formed.

  Further, as shown in FIG. 1, one end of the external restraining members 60, 70, 80, and 90 is provided at the center of the upper long side, the lower long side, the left short side, and the right short side of the end plate 10 a. Recesses 12a, 13a, 14a, 15a having rectangular shapes for fixing the parts with bolts are formed. Further, as shown in FIG. 2 (a), external restraining members 60, 70, 80, 90 are provided at the center of the upper long side, the lower long side, the left short side, and the right short side of the end plate 10b. Recesses 12b, 13b, 14b, and 15b having rectangular shapes for fixing the other end portions with bolts are formed.

  Further, the portions excluding both ends of each external restraining member 60, 70, 80, 90 are brought into contact with the inner side walls of the respective fitting recesses 46, 47, 48, 49 having the triangular shape described above. As possible, it has a trapezoidal cross-sectional shape. Further, both end portions of each external restraining member 60, 70, 80, 90 are recessed portions 12a, 13a, 14a, 15a formed in the end plate 10a, and recessed portions 12b, 13b, 14b formed in the end plate 10b, It has a rectangular cross-sectional shape so that it can be fitted into 15b.

  FIG. 2C shows an enlarged region R in FIG. As shown in FIG. 2C, in the present embodiment, the fitting recess 46 and the fitting recess 46 of the external restraining member 60 each have the shape described above. Therefore, when the external restraint member 60 is fitted to the fitting recesses 46 formed in the plurality of single cells 40 and an external force F is applied in a direction perpendicular to the side surface of the laminated body, the inner wall surface of the fitting recesses 46 is applied. The forces fa and fb act in a distributed manner in two directions different from the direction of the external force F. Although the description is omitted, the same applies to the case where the external restraining members 70, 80, 90 are fitted into the fitting recesses 47, 48, 49, respectively. Thus, when the external restraint member 60 is fixed to the plurality of stacked unit cells 40, the external restraint member 60 is applied to the external restraint member 60 in the fitting recess by applying an external force F in one direction. The external restraint members 60, 70, 80, 90 can be easily brought into contact with the plurality of single cells 40.

  The fastening member 50 and the external restraining members 60, 70, 80, 90 are made of metal such as steel in order to ensure rigidity. These surfaces are coated with an insulating film. By doing so, it is possible to ensure insulation between the fastening member 50 and the external restraint members 60, 70, 80, 90 and the plurality of single cells 40.

  According to the fuel cell stack 100 of the first embodiment described above, the four external restraining members 60, 70, 80, 90 are arranged in a plane parallel to the stacking direction of the stacked single cells 40 in the entire stacking direction. It can be fixed in a state of being in contact with each other, that is, with no gaps between the four external restraint members 60, 70, 80, 90 and the plurality of single cells 40. Therefore, in the fuel cell stack 100, even when an impact force is applied from the direction perpendicular to the stacking direction of the plurality of single cells 40, positional deviation in the direction perpendicular to the stacking direction of the single cells 40 is suppressed. can do.

B. Second embodiment:
FIG. 3 is a perspective view showing a schematic configuration of a fuel cell stack 100A as a second embodiment of the present invention. This fuel cell stack 100A has substantially the same structure as the fuel cell stack 100 of the first embodiment described above. However, as shown in FIG. 3, in the fuel cell stack 100A of the second embodiment, the plurality of external restraining members 60A, 70A, 80A, 90A are tightened at both ends using wires W, It is fixed to a plurality of single cells 40. The wire W is connected to an adjusting tool Ta for adjusting the tightening force of the wire W. By doing so, the tightening force of the wire W can be easily adjusted. The wire W and the adjustment tool Ta correspond to the annular elastic member and the adjustment unit in the present invention, respectively. In the present embodiment, the plurality of external restraining members 60A, 70A, 80A, 90A are fixed to the plurality of single cells 40 by tightening both ends thereof using the wires W. You may make it clamp the wire W to another site | part.

  In the fuel cell stack 100A of the second embodiment described above, the four external restraining members 60A, 70A, 80A, 90A are stacked in the same manner as the fuel cell stack 100 of the first embodiment described above. In a state where the cell 40 is in contact with the entire surface in the stacking direction parallel to the stacking direction, that is, there are gaps between the four external restraining members 60A, 70A, 80A, 90A and the plurality of single cells 40. Can be fixed in the absence. Therefore, in the fuel cell stack 100A, even when an impact force is applied from the direction perpendicular to the stacking direction of the plurality of single cells 40, positional deviation in the direction perpendicular to the stacking direction of the single cells 40 is suppressed. can do.

  Further, in the fuel cell stack 100A of the second embodiment, since the four external restraining members 60A, 70A, 80A, 90A are fastened by the wires W, they are fixed to the plurality of single cells 40 with a substantially uniform force. be able to.

C. Variations:
As mentioned above, although several embodiment of this invention was described, this invention is not limited to such embodiment at all, and implementation in a various aspect is possible within the range which does not deviate from the summary. It is. For example, the following modifications are possible.

C1. Modification 1:
In the first embodiment and the second embodiment, the fitting recesses 46, 47, 48, 49 are provided on the surface parallel to the stacking direction of the stacked body in which the plurality of single cells 40 are stacked. Although the external restraint members 60, 70, 80, 90 or the external restraint members 60A, 70A, 80A, 90A are brought into contact with and fitted to the inner wall surfaces, the present invention is not limited to this. .

  FIG. 4 is an explanatory view schematically showing an external restraint structure of a plurality of single cells 40B in the fuel cell stack as the first modification. Here, only the external restraint structure of the plurality of single cells 40B will be described, and detailed description of the entire fuel cell stack will be omitted.

  As illustrated, in the present modification, each of the plurality of single cells 40B has a hexagonal planar shape. Then, as shown in FIG. 4A, in each single cell 40B, the ridges 40Be1 and 40Be2 facing each other have external constraining members 80B having fitting recesses 80Bd fitted to the ridges 40Be1, respectively. And the external restraint member 90B which has fitting recessed part 90Bd fitted with ridge part 40Be2 contact | abuts, and is arrange | positioned (FIG.4 (b)). The external restraining members 80B and 90B may be fixed to the end plates arranged at both ends of the fuel cell stack by bolts (not shown), like the fuel cell stack 100 of the first embodiment. Similarly to the fuel cell stack 100A of the second embodiment, it may be fixed by a wire (not shown).

  Also by the external restraint structure of the modification 1 demonstrated above, the two external restraint members 80B and 90B can be fixed in a state without a gap between the external restraint members 80B and 90B and the plurality of single cells 40B. Therefore, in the fuel cell stack, even when an impact force is applied from the direction perpendicular to the stacking direction of the plurality of single cells 40A, positional deviation in the direction perpendicular to the stacking direction of the single cells 40A is suppressed. be able to.

  In the fuel cell stack of Modification 1 described above, the plurality of single cells 40B are externally restrained by the two external restraining members 80B and 90B. However, the present invention is not limited to this. For example, the plurality of single cells 40B You may make it contact an external restraint member with each ridge part, respectively. Further, the planar shape of the single cell 40B is not limited to a hexagon, and may be other shapes.

C2. Modification 2:
FIG. 5 is an explanatory view schematically showing an external restraint structure of a plurality of single cells 40C in the fuel cell stack as the second modification. Here, only the external restraint structure of the plurality of single cells 40C will be described, and a detailed description of the entire fuel cell stack will be omitted.

  As shown in the drawing, in the present modification, each of the plurality of single cells 40C has an octagonal planar shape. As shown in FIG. 5 (a), in each single cell 40C, the side restraints 60C and 70C and the external restraint members are respectively provided on the side faces 46C and 47C and the side faces 48C and 49C facing each other. 80C and 90C are disposed in contact with each other (FIG. 5B). The external restraining members 60C, 70C, 80C, and 90C are fixed to the end plates disposed at both ends of the fuel cell stack by bolts (not shown) as in the fuel cell stack 100 of the first embodiment. Alternatively, like the fuel cell stack 100A of the second embodiment, it may be fixed by a wire (not shown).

  Also by the external restraint structure of the modified example 2 described above, there are no gaps between the four external restraint members 60C, 70C, 80C, 90C and the external restraint members 60C, 70C, 80C, 90C and the plurality of single cells 40C. Can be fixed in the state. Therefore, in the fuel cell stack, even when an impact force is applied from the direction perpendicular to the stacking direction of the plurality of single cells 40C, positional deviation in the direction perpendicular to the stacking direction of the single cells 40C is suppressed. be able to.

  In the fuel cell stack of Modification 2 described above, the plurality of single cells 40C are externally restrained by the four external restraining members 60C, 70C, 80C, and 90C. An external restraining member may be brought into contact with all the side surfaces of the single cell 40C. Further, the planar shape of the single cell 40C is not limited to an octagon, and may be other shapes.

C3. Modification 3:
In the first embodiment and the second embodiment, the shape of the fitting recesses 46, 47, 48, and 49 is triangular. However, the present invention is not limited to this, and other shapes may be used. Good. However, the fitting recesses 46, 47, 48, 49 are fitted with the external restraint members 60, 70, 80, 90, respectively, and are parallel to the external restraint members 60, 70, 80, 90 in the stacking direction of the laminate. When an external force is applied in a direction perpendicular to the surface, the external force preferably has an inner wall surface acting in a distributed manner in at least two directions different from the direction of the external force. Moreover, the number of the fitting recessed parts mentioned above is not restricted to four, It can set arbitrarily.

C4. Modification 4:
In the first embodiment and the second embodiment, the plurality of single cells 40 are fastened using the fastening member 50 having a predetermined length. However, the present invention is limited to this. Absent. For example, a fastening structure in which a disc spring is disposed at one end in the stacking direction of the unit cells 40 in the fuel cell stacks 100 and 100A, and a plurality of unit cells 40 are fastened with a predetermined fastening force by the elastic force of the disc springs. May be applied.

C5. Modification 5:
In the first embodiment and the second embodiment, the fastening structure of the fuel cell stack and the external restraint structure of the plurality of single cells 40 are configured separately, but both are formed using a common member. You may make it comprise. That is, for example, in the fuel cell stack 100, the fastening structure of the fuel cell stack 100 may be configured using the external restraining members 60, 70, 80, and 90.

1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as a first embodiment of the present invention. It is explanatory drawing which shows the AA cross section in FIG. It is a perspective view which shows schematic structure of fuel cell stack 100A as 2nd Example of this invention. FIG. 10 is an explanatory diagram schematically showing an external restraint structure of a plurality of single cells 40B in a fuel cell stack as Modification 1. 10 is an explanatory view schematically showing an external restraint structure of a plurality of single cells 40C in a fuel cell stack as a second modification. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100,100A ... Fuel cell stack 10a, 10b ... End plate 12a, 13a, 14a, 15a, 12b, 13b, 14b, 15b ... Recess 20a, 20b ... Insulating plate 30a, 30b ... Current collecting plate 32a, 32b ... Output terminal 40 , 40A, 40B, 40C ... single cell 45 ... notch 46, 47, 48, 49 ... fitting recess 40Be1, 40Be2 ... edge 46C, 47C, 48C, 49C ... side face 50 ... fastening member 52 ... bolt 60, 70 , 80, 90 ... External restraint member 60A, 70A, 80A, 90A ... External restraint member 80B, 90B ... External restraint member 80Bd, 90Bd ... Fitting recess 60C, 70C, 80C, 90C ... External restraint member W ... Wire Ta ... Adjustment Instrument

Claims (7)

A fuel cell stack,
A laminate in which a plurality of single cells are laminated;
In the stacked body, an external constraining member for suppressing displacement of the single cell in a direction perpendicular to a stacking direction of the plurality of single cells, the parallel stack being parallel to the stacking direction of the stacked body A plurality of external restraining members fixed to the laminate in a state of being in contact with the entire surface in the laminating direction;
A fuel cell stack comprising: The fuel cell stack according to claim 1, wherein
A fuel cell stack, wherein a plurality of fitting recesses that are respectively fitted to the plurality of external restraining members are formed on a surface parallel to the stacking direction of the stack. The fuel cell stack according to claim 2, wherein
When the external constraining member is fitted into the fitting recess and an external force is applied to the external constraining member in a direction perpendicular to the stacking direction of the laminate, the external force is in the direction of the external force. A fuel cell stack having inner wall surfaces acting in a distributed manner in at least two directions different from the above. The fuel cell stack according to claim 1, wherein
The laminate has ridges parallel to the lamination direction,
The external restraining member is a fuel cell stack including a fitting recess that fits into the ridge. The fuel cell stack according to any one of claims 1 to 4,
The fuel cell stack, wherein the plurality of external restraining members are fixed to the laminate by being fastened to the laminate using an annular elastic member. The fuel cell stack according to claim 5, further comprising:
A fuel cell stack comprising an adjusting unit for adjusting a tightening force of the plurality of external restraining members by the linear elastic member. The fuel cell stack according to any one of claims 1 to 6,
The external restraining member is made of metal,
A fuel cell stack, wherein an insulating member is interposed between the external restraining member and the laminate.

Images