JP2012169096A - Fuel cell stack manufacturing method, fuel cell stack, separator, and sealing member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of a fuel cell stack composed of fuel battery cells and sealing members which are alternately laminated one on another.SOLUTION: Following steps are included: a temporary assemble step in which sealing members 50 are temporarily assembled to surfaces on one side of plural fuel battery cells 40 respectively and a lamination step in which temporarily assembled the plural fuel battery cells 40 and sealing members 50 are laminated one on another. A separator 44 in each fuel battery cell 40 has a pair of convex parts 44d1 and 44d2 which are used for positioning the sealing members 50 during the temporary assembly. The sealing members 50 each have bending elasticity and also are shaped so that when the sealing member 50 is bent, peripheral parts 50e thereof can be fitted in between the pair of convex parts 44d1 and 44d2 of the separator 44. The temporary assemble step further includes a step in which the sealing member 50 is bent and the peripheral parts 50e thereof are fitted in between the pair of convex parts 44d1 and 44d2 of the separator 44.

Description

  The present invention relates to a method for manufacturing a fuel cell stack, a fuel cell stack, a separator, and a seal member.

  A fuel cell that generates electricity by an electrochemical reaction between a fuel gas and an oxidant gas has attracted attention as an energy source. This fuel cell is generally used in the form of a fuel cell stack in which a plurality of fuel cells are stacked. The fuel battery cell is configured, for example, by sandwiching a power generator including a membrane electrode assembly between a pair of separators.

  In this fuel cell stack, a seal member may be interposed between the fuel cells. And as this sealing member, the sealing material with which the planar insulating sheet and the linear gas sealing material described in the following patent document 1 were integrated is applicable, for example.

JP 2002-158018 A

  However, when the above-described fuel cell stack is manufactured by applying the sealing material described in Patent Document 1 as a sealing member, the positioning performance of the sealing member when the fuel cells and the sealing member are alternately stacked is poor. Also, the productivity of the fuel cell stack was bad.

  The present invention has been made to solve the above-described problems, and an object thereof is to improve the productivity of a fuel cell stack in which fuel cells and seal members are alternately stacked.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

[Application Example 1]
A method for manufacturing a fuel cell stack, comprising:
A step of preparing a plurality of fuel cells each having a power generator sandwiched between a pair of separators;
Preparing a plurality of sealing members for sealing between the plurality of fuel cells; and
A temporary assembling step of temporarily assembling the seal member on one surface of each of the plurality of fuel cells;
A stacking step of stacking the plurality of temporarily assembled fuel cell units and the seal member so that the fuel cell units and the seal member are alternately disposed;
With
In the fuel cell, the separator on the side on which the seal member is temporarily assembled is a protrusion protruding in a direction perpendicular to the surface of the separator on the surface on which the seal member is temporarily assembled. A pair of convex portions for positioning for temporary assembly of the seal member, which are arranged at an interval narrower than the width of the seal member,
The seal member has bending elasticity, and has a shape that allows the peripheral portion of the seal member to be fitted between the pair of convex portions in the separator by bending the seal member.
The temporary assembly step includes a step of bending the seal member and fitting a peripheral portion of the seal member between the pair of convex portions in the separator.
Production method.

  In the fuel cell stack manufacturing method of Application Example 1, in the temporary assembly step, the peripheral edge of the seal member can be fitted between the pair of convex portions provided in the separator. Positioning can be performed. Further, since the sealing member is fixed between the pair of convex portions in the separator and integrated with the fuel cell by the bending elastic force when bent, the stacking step is performed in the stacking step. The number of parts to be reduced can be reduced. Therefore, the productivity of the fuel cell stack can be improved.

  In the temporary assembly step, when the seal member fixed to one separator in the fuel cell is pressed in contact with the separator in the fuel cell stacked on the seal member in the stacking step. The fitting is released by the reaction force of the bending elastic force of the sheet member. And this seal member fits in the desired position between fuel cells, with almost no displacement caused by friction with the separator.

[Application Example 2]
A method for manufacturing a fuel cell stack according to Application Example 1,
The sealing member has an acute-angle cross-sectional shape of the peripheral edge fitted between the pair of convex portions in the separator.
Production method.

  According to the manufacturing method of the fuel cell stack of Application Example 2, the peripheral edge of the seal member is easily caught by the pair of protrusions in the separator, compared to the case where the cross-sectional shape is changed to another shape. The fitting property of the peripheral part of the sealing member to the can be improved.

[Application Example 3]
A method of manufacturing a fuel cell stack according to Application Example 1 or 2,
The seal member includes a sheet-like core material having bending elasticity, and a plurality of seal projections provided on the surface of the core material and in contact with the separator.
Production method.

  In the fuel cell stack manufacturing method of Application Example 3, since the seal member includes the seal protrusion, in the stacking step, the seal member and the separator are released from the fitting while being in contact with the plurality of seal protrusions. . For this reason, it is possible to prevent positional deviation of the seal member in the stacking process as compared with a configuration in which the almost entire surface of the seal member is in contact with the separator.

[Application Example 4]
A method of manufacturing a fuel cell stack according to Application Example 3,
The core material and the seal protrusion are made of different materials.
Production method.

  In the fuel cell stack manufacturing method of Application Example 4, for example, the core material and the sheet convex portion are made of materials having different properties, such as the core material being resin and the sheet convex portion being rubber. Can do. Therefore, the freedom degree about design of a sealing member can be improved.

[Other application examples]
A fuel cell stack formed by laminating a plurality of fuel cells in which a power generator is sandwiched between a pair of separators and a sealing member having bending elasticity for sealing a plurality of manifolds provided in the fuel cells. There,
The surface of the fuel cell in contact with the seal member includes a plurality of protrusions protruding in a direction perpendicular to the separator surface,
The plurality of convex portions are arranged at intervals narrower than the width of the seal member.
Fuel cell stack.

  In addition to the configuration as a method for manufacturing the fuel cell stack described above, the present invention provides a fuel cell stack manufactured by the method for manufacturing a fuel cell stack described above, a separator used for the fuel cell stack, and a seal member used for the fuel cell stack. The present invention can also be configured. In addition, in each aspect, it is possible to apply the various additional elements shown above.

1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as one embodiment of the present invention. It is explanatory drawing which shows the fuel battery cell 40 and the sealing member 50. FIG. 3 is an explanatory view schematically showing a main part of a manufacturing process of the fuel cell stack 100. FIG.

Hereinafter, embodiments of the present invention will be described based on examples.
A. Fuel cell stack configuration:
FIG. 1 is a perspective view showing a schematic configuration of a fuel cell stack 100 as an embodiment of the present invention. This fuel cell stack 100 generally has a stack structure in which fuel cell cells 40 in which a power generation body including a membrane electrode assembly is sandwiched between separators and seal members 50 are alternately arranged and stacked. Yes. In this example, a solid polymer membrane was used as the electrolyte membrane. The number of stacked fuel cells 40 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 includes, from one end, an end plate 10a, an insulating plate 20a, a current collecting plate 30a, a plurality of fuel cells 40 and a seal member 50, a current collecting plate 30b, an insulating plate 20b, and an end plate 10b. It is comprised by laminating | stacking in this order. In the fuel cell stack 100, supply manifolds (hydrogen supply manifold, air supply manifold, cooling water supply manifold) for distributing and supplying hydrogen, air, and cooling water to the respective membrane electrode assemblies are provided. Also, an anode offgas and cathode offgas discharged from the anode and cathode of each membrane electrode assembly, and a discharge manifold for collecting cooling water and discharging it outside the fuel cell stack 100 (anode offgas discharge manifold, cathode offgas) A discharge manifold and a cooling water discharge manifold) are formed.

  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.

  In the fuel cell stack 100, the plurality of fuel 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 at any part of the stack structure or to prevent gas leakage. It is fastened in a state where a predetermined fastening load is applied in the laminating direction. Hereinafter, the fastening structure of the fuel cell stack 100 will be described.

  In the present embodiment, notches having rectangular shapes are provided at the four corners of the insulating plates 20a and 20b and the current collecting plates 30a and 30b (not shown). Further, as will be shown later, notches having rectangular shapes are also provided at the four corners of the plurality of fuel cells 40 and the seal member 50 (see FIG. 2). And these are made to contact | abut the square-column-shaped rod member 60 to each notch part, and while applying a fastening load to the lamination direction of a stack structure, both ends of each rod member 60 are end plate 10a, 10b with the volt | bolt 62. It is fastened by fixing to each of the four corners.

  Note that the above-described fastening load in the fuel cell stack 100 is obtained by, for example, inserting a spacer between the end plate 10a and the insulating plate 20a, or between the end plate 10b and the insulating plate 20b. Or by adjusting the thickness of the insulating plates 20a and 20b. Further, since the length of the rod member 60 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. In the fuel cell stack 100 of the present embodiment, the rod members 60 are brought into contact with the notches provided at the four corners of the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the plurality of fuel cells 40, respectively. By doing so, each positioning can be performed.

  Further, in the fuel cell stack 100 of this embodiment, the end plate 10a, the end plate 10b, the insulating plates 20a and 20b, the current collecting plates 30a and 30b, and the centers of the upper and lower side surfaces of the plurality of fuel cells 40 are arranged. A notch is formed in the part. Then, the fastening member 70 is fitted into these notches, and both end portions of the fastening member 70 are fixed to the end plates 10a and 10b with bolts 72, respectively. The curved deformation of the plates 10a and 10b is prevented.

  The rod member 60 and the fastening member 70 are made of metal such as steel in order to ensure rigidity. These surfaces are coated with an insulating film in order to ensure insulation between the fuel cells 40 and between the fuel cells 40 and the end plates 10a and 10b.

  FIG. 2 is an explanatory diagram showing the fuel battery cell 40 and the seal member 50. A plan view of the fuel battery cell 40 is shown in FIG. Moreover, the top view of the sealing member 50 was shown in FIG.2 (b).

  As shown in FIG. 2 (a), the fuel cell 40 is formed with a plurality of through holes 40h constituting the various manifolds described above along each side. Further, as described above, cutout portions each having a rectangular shape are provided at the four corners of the fuel cell 40 and the central portions of the upper and lower side surfaces. Moreover, although illustration is abbreviate | omitted in Fig.2 (a), the convex parts 44d1 and 44d2 mentioned later are formed in the surface of the fuel cell 40 (refer FIG. 3).

  As shown in FIG. 2B, the seal member 50 includes a core member 52 and a seal convex portion 54 described later (see FIG. 3). Similarly to the fuel battery cell 40, the seal member 50 is also formed with a plurality of through holes 50h constituting various manifolds along each side. And the seal convex part 54 is formed in the circumference | surroundings (both surfaces of the core material 52) of the some through-hole 50h, respectively. In addition, as described above, cutout portions each having a rectangular shape are formed at the four corners of the seal member 50.

B. Manufacturing process of fuel cell stack:
FIG. 3 is an explanatory view schematically showing the main part of the manufacturing process of the fuel cell stack 100. First, as shown in FIG. 3A, a fuel cell 40 and a seal member 50 are prepared.

  The fuel cell 40 is configured by sandwiching a power generator 42 including a membrane electrode assembly between a pair of separators 44 and 46. In the fuel cell 40, one separator 44 is formed with a pair of convex portions 44 d 1 and 44 d 2 that project in a direction perpendicular to the surface of the separator 44. The distance between the convex portion 44d1 and the convex portion 44d2 is D1, which is narrower than the illustrated width D2 of the seal member 50. The convex portions 44d1 and 44d2 are used for positioning when the seal member 50 is temporarily assembled, as will be described later. Note that the shapes of the protrusions 44d1 and 44d2 when viewed from the direction perpendicular to the surface of the separator 44 may be linear or island-shaped, respectively. Moreover, the cross-sectional shape of the convex portions 44d1 and 44d2 is not limited to the illustrated rectangular shape, and various shapes such as a trapezoidal shape, a semicircular shape, and a semielliptical shape can be applied. Further, each of the convex portions 44d1 and 44d2 may be one or a plurality of convex portions arranged on a straight line.

  The seal member 50 includes a sheet-like core material 52 having bending elasticity, and a plurality of seal convex portions 54 provided on the surface of the core material 52 and in contact with the separators 44 and 46. In this embodiment, the sealing member 50 (core member 52) has an acute-angle cross-sectional shape when the sealing member 50 is cut in the illustrated width direction. “The cross-sectional shape has an acute angle shape” means that the angle formed by two sides in the cross section is an acute angle, and may be an acute angle shape other than the illustrated acute angle shape. In the present embodiment, the core material 52 is made of resin, and the seal projection 54 is made of rubber.

  Next, as shown in FIG. 3B, the sealing member 50 (core material 52) is curved, and the peripheral portion 50 e of the sealing member 50 is fitted between the convex portions 44 d 1 and 44 d 2 of the separator 44. At this time, the seal member 50 is fixed between the convex portions 44d1 and 44d2 of the separator 44 by the bending elastic force when bent, and is integrated with the fuel cell 40 (temporary assembly step).

  Next, as shown in FIG.3 (c), the fuel cell 40 and the sealing member 50 are arrange | positioned alternately by the fuel cell 40 and the sealing member 50 which were integrated by the temporary assembly process. (Lamination process). At this time, when the sealing member 50 fixed to the separator 44 is pressed in contact with the separator 46 in the fuel cell 40 stacked on the sealing member 50 (contact process), the bending elastic force of the core member 52 is bent. The above-described fitting is released by the reaction force (fitting releasing step). The seal member 50 is accommodated at a desired position between the fuel cells 40 with almost no displacement due to friction with the separator 44.

  As shown in FIG. 3 (d), after the stacking step, the current collector plates 30a and 30b, the insulating plates 20a and 20b shown in FIG. The fuel cell stack 100 is completed by laminating the plates 10a and 10b and fastening them as described above.

  According to the manufacturing process of the fuel cell stack 100 of the present embodiment described above, the peripheral portion 50e of the seal member 50 is fitted between the pair of convex portions 44d1 and 44d2 provided in the separator 44 in the temporary assembly step. Therefore, the sealing member 50 can be accurately positioned. Furthermore, since the sealing member 50 is fixed between the pair of convex portions 44d1 and 44d2 in the separator 44 and integrated with the fuel battery cell 40 by the bending elastic force when bent, by the temporary assembly step, In the lamination process, the number of parts to be laminated can be reduced. Therefore, the productivity of the fuel cell stack 100 can be improved.

  Further, according to the manufacturing process of the fuel cell stack 100 of the present embodiment, the sealing member 50 is integrated with the fuel battery cell 40 by the temporary assembly process. Therefore, in the stacking process, the integrated fuel battery cell 40 is integrated. In addition, the seal member 50 can be stacked in the vertical direction or in the horizontal direction, and the assembly posture can be prevented from being restricted.

  Further, in the fuel cell stack 100 of the present embodiment, the sealing member 50 has an acute-angle cross-sectional shape of the peripheral edge portion 50e fitted between the pair of convex portions 44d1 and 44d2 in the separator 44. The peripheral edge 50e of the seal member 50 is more easily caught by the pair of convex portions 44d1 and 44d2 in the separator 44 than when the cross-sectional shape is changed to other shapes, and the seal to the pair of convex portions 44d1 and 44d2 in the separator 44 The fitting property of the peripheral edge portion 50e of the member 50 can be improved.

  Further, in the fuel cell stack 100 of the present embodiment, the seal member 50 includes a sheet-like core material 52 having bending elasticity, and a plurality of seal protrusions provided on the surface of the core material 52 and in contact with the separators 44 and 46. 54, the sealing member 50 and the separators 44 and 46 are released from the fitting while being in contact with each other by the plurality of seal protrusions 54 in the stacking step. For this reason, it is possible to prevent positional deviation of the seal member 50 in the stacking process as compared with the configuration in which the substantially entire surface of the seal member and the separators 44 and 46 are in contact with each other.

  In the fuel cell stack 100 of the present embodiment, since the core member 52 and the seal protrusion 54 are made of different materials in the seal member 50, the degree of freedom in designing the seal member 50 can be improved.

  Further, in the fuel cell stack 100 of the present embodiment, the outer dimension of the seal member 50 can be made smaller than the outer dimension of the separators 44 and 46, so the outer dimension of the seal member 50 is the outer dimension of the separators 44 and 46. The cost of the seal member 50 can be reduced as compared with the case where the dimensions are almost equal to each other.

C. Variations:
Although the embodiments of the present invention have been described above, the present invention is not limited to such embodiments, and can be implemented in various modes without departing from the scope of the present invention. For example, the following modifications are possible.

C1. Modification 1:
In the above embodiment, the sealing member 50 has an acute-angle cross-sectional shape of the peripheral edge portion 50e when the sealing member 50 is cut in the width direction of the sealing member 50. Not limited. The cross-sectional shape of the peripheral edge portion 50e of the seal member 50 may be another shape.

C2. Modification 2:
In the above embodiment, the sealing member 50 includes the sheet-like core material 52 having bending elasticity, and the seal convex portions 54 provided on both surfaces of the core material 52 and abutting against the separators 44 and 46. However, the present invention is not limited to this. For example, the sealing member 50 may have a flat shape.

C3. Modification 3:
In the said Example, although the core material 52 and the seal convex part 54 shall consist of different materials in the sealing member 50, this invention is not limited to this. In the seal member 50, the core member 52 and the seal projection 54 may be made of the same material (for example, rubber).

DESCRIPTION OF SYMBOLS 100 ... Fuel cell stack 10a, 10b ... End plate 20a, 20b ... Insulating plate 30a, 30b ... Current collecting plate 32a, 32b ... Output terminal 40 ... Fuel cell 42 ... Electric power generation body 44 ... Separator 44d1, 44d2 ... Convex part 46 ... Separator 50 ... Seal member 50e ... Peripheral part 52 ... Core material 54 ... Seal convex part 60 ... Rod member 62 ... Bolt 70 ... Fastening member 72 ... Bolt

Claims (11)

A method for manufacturing a fuel cell stack, comprising:
A step of preparing a plurality of fuel cells each having a power generator sandwiched between a pair of separators;
Preparing a plurality of sealing members for sealing between the plurality of fuel cells; and
A temporary assembling step of temporarily assembling the seal member on one surface of each of the plurality of fuel cells;
A stacking step of stacking the plurality of temporarily assembled fuel cell units and the seal member so that the fuel cell units and the seal member are alternately disposed;
With
In the fuel cell, the separator on the side on which the seal member is temporarily assembled is a protrusion protruding in a direction perpendicular to the surface of the separator on the surface on which the seal member is temporarily assembled. A pair of convex portions for positioning for temporary assembly of the seal member, which are arranged at an interval narrower than the width of the seal member,
The seal member has bending elasticity, and has a shape that allows the peripheral portion of the seal member to be fitted between the pair of convex portions in the separator by bending the seal member.
The temporary assembly step includes a step of bending the seal member and fitting a peripheral portion of the seal member between the pair of convex portions in the separator.
Production method. A method of manufacturing a fuel cell stack according to claim 1,
The sealing member has an acute-angle cross-sectional shape of the peripheral edge fitted between the pair of convex portions in the separator.
Production method. A method of manufacturing a fuel cell stack according to claim 1 or 2,
The seal member includes a sheet-like core material, and a plurality of seal convex portions provided on the surface of the core material and in contact with the separator.
Production method. A method for producing a fuel cell stack according to claim 3,
The core material and the seal protrusion are made of different materials.
Production method.   A fuel cell stack manufactured by the manufacturing method according to claim 1. A plurality of fuel cells each having a power generator sandwiched between a pair of separators are prepared, a plurality of sealing members for sealing between the plurality of fuel cells are prepared, and on one surface of the plurality of fuel cells, Produced by temporarily assembling the seal member and laminating the plurality of temporarily assembled fuel cell units and the seal member so that the fuel cell units and the seal member are alternately arranged. Used in the fuel cell stack, in the fuel cell, the separator on the side on which the seal member is temporarily assembled,
Protrusions projecting in a direction perpendicular to the surface of the separator on the surface on which the seal member is temporarily assembled, and are arranged at intervals narrower than the width of the seal member. Provided with a pair of convex portions for positioning for temporary assembly,
Separator. A plurality of fuel cells each having a power generator sandwiched between a pair of separators are prepared, a plurality of sealing members for sealing between the plurality of fuel cells are prepared, and on one surface of the plurality of fuel cells, Produced by temporarily assembling the seal member and laminating the plurality of temporarily assembled fuel cell units and the seal member so that the fuel cell units and the seal member are alternately arranged. The sealing member used for a fuel cell stack,
In the fuel cell, the separator on the side on which the seal member is temporarily assembled is a protrusion protruding in a direction perpendicular to the surface of the separator on the surface on which the seal member is temporarily assembled. A pair of convex portions for positioning for temporary assembly of the seal member, which are arranged at an interval narrower than the width of the seal member,
The seal member has bending elasticity and has a shape that allows the peripheral portion of the seal member to be fitted between the pair of convex portions in the separator by bending the seal member.
Seal member. The seal member according to claim 7,
The cross-sectional shape of the peripheral edge fitted between the pair of convex portions in the separator has an acute angle shape,
Seal member. The seal member according to claim 7 or 8,
A sheet-like core material;
A seal projection provided on each side of the core material and in contact with the separator;
A seal member. The seal member according to claim 9,
The core material and the seal protrusion are made of different materials.
Seal member. A fuel cell stack formed by laminating a plurality of fuel cells in which a power generator is sandwiched between a pair of separators and a sealing member having bending elasticity for sealing a plurality of manifolds provided in the fuel cells. There,
The surface of the fuel cell in contact with the seal member includes a plurality of protrusions protruding in a direction perpendicular to the separator surface,
The plurality of convex portions are arranged at intervals narrower than the width of the seal member.
Fuel cell stack.

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