JP2015187953A - Method of manufacturing fuel cell stack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the assembly accuracy of a fuel cell stack by preventing that a reference is deformed due to thermocompression bonding in a process for manufacturing an assembly, and cannot be used in the later process.SOLUTION: A method of manufacturing a fuel cell stack includes a step 1 and a step 2. The step 1 is a step for manufacturing a battery assembly by laminating a separator and a thermoplastic resin frame, and positioning of the separator and the resin frame is performed based on a first reference when laminating. The second step is a step for laminating a plurality of battery assemblies, and positioning of each battery assembly at the time of lamination is performed based on a second reference of different shape from the first reference.

Description

  The present invention relates to a method for manufacturing a fuel cell stack.

  In a conventional fuel cell stack manufacturing method, for example, as described in Patent Document 1, a hole is made in a structural member such as a resin frame or a separator constituting the fuel cell, and a jig positioning pin is passed through the hole. Thus, the positions of the constituent members are fixed and lamination is performed. In this case, the constituent members are heated and pressure-bonded.

JP-A-2005-79024

  However, in the conventional technology, when the resin frame is made thermoplastic, the hole provided in the resin frame is deformed by thermocompression bonding, and the hole cannot be used for positioning in the subsequent process. was there. This causes a problem that the assembly accuracy of the fuel cell stack is lowered.

  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.

  One aspect of the present invention is a method for manufacturing a fuel cell stack. This fuel cell stack manufacturing method is a step of stacking a separator and a thermoplastic resin frame to form a battery assembly, and positioning the separator and the resin frame during the stacking as a first reference. And a step of laminating a plurality of the battery assemblies, wherein the positioning of each battery assembly during the lamination is based on a second reference having a shape different from the first reference. And a step of performing.

  According to this method for manufacturing a fuel cell stack, even when the first reference is deformed in the step of creating the battery assembly, the second assembly can be used to position the battery assemblies when they are stacked. For this reason, the battery assemblies can be stacked with high positioning accuracy. Therefore, according to the fuel cell stack manufacturing method of this embodiment, the assembly accuracy of the fuel cell stack can be improved.

  The present invention can be realized in various forms. For example, it can be realized in the form of a fuel cell stack manufacturing apparatus or the like having a configuration corresponding to each step of the manufacturing method of the fuel cell stack of the above aspect.

It is explanatory drawing which shows the manufacturing method of the fuel cell stack as 1st Embodiment of this invention. It is a top view of the resin frame prepared in the process 1. 4 is a plan view of a separator prepared in step 1. FIG. It is a top view of the resin frame used in 2nd Embodiment. It is a top view of the separator used in 2nd Embodiment.

Next, an embodiment of the present invention will be described.
A. First embodiment:
FIG. 1 is an explanatory view showing a method of manufacturing a fuel cell stack as a first embodiment of the present invention. The fuel cell stack manufactured by this manufacturing method has a structure (so-called stack structure) in which a plurality of cell assemblies constituting one unit of the fuel cell are stacked. In this embodiment, the fuel cell is a solid polymer type.

  As shown in FIG. 1, according to this fuel cell stack manufacturing method, a cell assembly (hereinafter simply referred to as “assembly”) is created (step 1), and a predetermined number of the produced assemblies are stacked (step 2). The fuel cell stack is manufactured by fastening (step 3).

  In step 1, the resin frame 20 containing the power generation body 10 and the separator 40 are prepared, and the separators 40 and 40 are laminated on both surfaces of the resin frame 20, thereby producing the assembly 100. This lamination is performed by positioning the resin frame 20 and the separator 40 based on the first reference. The first reference is a reference hole inserted by a broken line in the figure, and details will be described later.

  The power generation body 10 has gas diffusion layers arranged on both surfaces of a membrane-electrode assembly (MEA). The resin frame 20 has a function of preventing the separators 40 and 40 from being short-circuited and preventing fluid (fuel gas, oxidant gas, cooling medium) passing through the power generation body 10 from leaking to the outside. . The resin frame 20 is formed of a thermoplastic resin such as polypropylene or polyethylene. The separator 40 has functions of gas barrier properties and electronic conductivity, and is formed of a metal member such as press-formed stainless steel, for example.

  In step 2, a predetermined number of assemblies 100 created in step 1 are stacked. This stacking is performed by positioning each assembly 100 based on the second reference. The second reference is a reference hole inserted by a broken line in the figure, and details will be described later.

  In step 3, a predetermined number of assemblies 100 stacked in step 2 are fastened using a fastening member (not shown) so that a predetermined fastening force is applied in the stacking direction.

  FIG. 2 is a plan view of the resin frame 20 prepared in step 1. As illustrated, the outer shape of the resin frame 20 is rectangular, and the power generation body 10 is accommodated in the central opening. At the outer edge portion of the resin frame 20, six through holes 21 to 26 that respectively constitute supply or discharge manifolds through which fuel gas, oxidant gas, and cooling medium flow are formed. A thermosetting adhesive 28 such as silicone, polyisobutylene, epoxy, urethane or the like is applied around each of the through holes 21 to 26.

  In one corner of the resin frame 20, a first positive reference hole 30a and a second positive reference hole 30b for the resin frame 20 are formed. The first and second positive reference holes 30a and 30b are circular. Further, at the diagonal positions of the first positive reference hole 30a and the second positive reference hole 30b in the resin frame 20, there are a first sub-reference hole 32a and a second sub-reference hole 32b for the resin frame 20. Is formed. The first and second sub-reference holes 32a and 32b have a long hole shape. The first positive reference hole 30a and the first sub reference hole 32a are the first reference for positioning used in the step 1, respectively. The second positive reference hole 30b and the second sub reference hole 32b are positioning second references used in step 2, respectively.

  FIG. 3 is a plan view of the separator 40 prepared in step 1. As shown in the drawing, the separator 40 also has a rectangular outer shape, and six through holes 41 to 46 constituting each manifold described above are formed in the outer edge portion. A groove channel 47 is formed on the surface of the separator 40 facing the power generator 10 at the center. The thick line in the figure is a sealing agent 48 such as a gasket. The sealing agent 48 forms an in-cell flow path for fuel gas, oxidant gas, or cooling medium.

  In one corner of the separator 40, a first positive reference hole 50a and a second positive reference hole 50b for the separator 40 are formed. The first and second positive reference holes 50a and 50b are circular like the first and second positive reference holes 30a and the positive reference hole 30b (FIG. 2) for the resin frame 20. Further, a first sub-reference hole 52a and a second sub-reference hole 52b for the separator 40 are formed at diagonal positions of the first positive reference hole 50a and the second positive reference hole 50b in the separator 40. ing. The first and second sub-reference holes 52a and 52b have a long hole shape, similar to the first and second sub-reference holes 32a and 32b (FIG. 2) for the resin frame 20. The first positive reference hole 50a and the first sub reference hole 52a are the first reference for positioning used in the step 1, respectively. The second positive reference hole 50b and the second sub reference hole 52b are positioning second references used in step 2, respectively.

  In the step 1, when the separators 40 and 40 are arranged on both surfaces of the resin frame 20, the reference holes 30a to 32b on the resin frame side and the 50a to 52b on the separator 40 side communicate with each other at corresponding positions. When the sizes of the reference hole on the resin frame side and the reference hole on the separator side communicating with each other are compared, the following dimensional relationship is obtained. The first primary reference hole 30a and the first secondary reference hole 32a on the resin frame 20 side have the same size as the first primary reference hole 50a and the first secondary reference hole 52a on the separator 40 side, respectively. . On the other hand, the second positive reference hole 30b and the second secondary reference hole 32b on the resin frame 20 side are each one turn compared to the second positive reference hole 50b and the second secondary reference hole 52b on the separator 40 side. It is a large size (only predetermined values α and β described later).

The dimensional relationship described above can be expressed as follows.
R1 = S1
R3 = S3
R2 = S2 + α
R4 = S4 + β

here,
R1: Radius of the first positive reference hole 30a in the resin frame 20 (FIG. 2) R2: Radius of the second positive reference hole 30b in the resin frame 20 (FIG. 2) R3: First of the resin frame 20 (FIG. 2) The minor axis length of the secondary reference hole 32a R4: the minor axis length of the second subsidiary reference hole 32b in the resin frame 20 (FIG. 2) S1: the first regular reference hole 50a in the separator 40 (FIG. 3) Radius S2: radius of the second positive reference hole 50b in the separator 40 (FIG. 3) S3: length of the short axis of the first sub-reference hole 52a in the separator 40 (FIG. 3) S4: separator 40 (FIG. 3) The length of the minor axis α of the second sub-reference hole 52b in FIG. 5 is a positive value, and the second positive reference hole 50b in the separator 40 is affected even if it is thermally deformed in consideration of expansion during curing. Dimension not given β: Positive value Dimension that does not affect the second sub-reference hole 52b in the separator 40 even when thermally deformed in consideration of expansion during curing

  In step 1, in detail, the separator 40, the resin frame 20, and the separator 40 are stacked in this order, and one is provided in the first positive reference hole 30a of the resin frame 20 and the first positive reference hole 50a of each separator 40. In addition, the positioning pin is inserted through the first sub-reference hole 32a of the resin frame 20 and the first sub-reference hole 52a of each separator 40. In this state, the resin frame 20 and the separators 40 and 40 are heat bonded. As a result, an assembly 100 that is a laminate of the separator 40, the resin frame 20, and the separator 40 is created.

  In step 2, in detail, each assembly 100 is stacked, and one positioning pin is placed in the second positive reference hole 30b of the resin frame 20 provided in each assembly 100 and the second positive reference hole 50b of each separator 40. And a single positioning pin is passed through the second sub-reference hole 32b of the resin frame 20 provided in each assembly 100 and the second sub-reference hole 52b of the separator 40. Since the second positive reference hole 30b and the second sub reference hole 32b of the resin frame 20 are deformed by the thermocompression bonding process in step 1, the pin is inserted, but the positioning reference is actually It is not. With each positioning pin inserted, each assembly 100 is thermocompression bonded. As a result, the thermosetting adhesive located between the assemblies 100 is solidified to form a laminate of the assemblies 100.

  As described above in detail, according to the method of manufacturing the fuel cell stack as the first embodiment, the second positive reference hole 30b and the second sub reference hole 32b provided in the resin frame 20 are provided in the separator 40. Compared to the provided second positive reference hole 50b and the second sub reference hole 52b, each has a size that is one size larger, and has a shape that can cope with thermal deformation. Conventionally, when thermocompression processing is performed in the process of creating an assembly, the resin in the resin frame protrudes into the reference hole, and the reference hole cannot be used in a subsequent process. On the other hand, in the present embodiment, as described above, the second positive reference hole 30b and the second sub reference hole 32b provided in the resin frame 20 have shapes that can cope with thermal deformation. In step 1, the resin does not protrude into the second primary reference hole 30b and the second secondary reference hole 32b. Therefore, in step 2, which is a subsequent step, each assembly 100 can be positioned using the second positive reference hole 30b and the second sub reference hole 32b, so that the assembly can be stacked with high accuracy. . Therefore, according to the manufacturing method of the fuel cell stack of the first embodiment, the assembly accuracy of the fuel cell stack can be improved.

  Moreover, the manufacturing method of the fuel cell stack as the first embodiment can assemble a material having a large difference in linear expansion coefficient between the resin frame and the separator, so that an inexpensive material can be selected. The following effects are produced. Furthermore, since it is not necessary to deburr the reference hole between the process 1 and the process 2, there is a secondary effect that the process can be reduced and the occurrence of quality defects such as scratches can be suppressed.

B. Second embodiment:
The fuel cell stack manufacturing method according to the second embodiment of the present invention is similar to the fuel cell stack manufacturing method according to the first embodiment in that an assembly is created by laminating a resin frame and a separator (step 1). The fuel cell stack is manufactured by stacking a predetermined number of the produced assemblies (step 2) and fastening (step 3). In the second embodiment, the shapes of the resin frame and the separator prepared in step 1 are different from those in the first embodiment.

  FIG. 4 is a plan view of the resin frame 20 used in the second embodiment. FIG. 5 is a plan view of the separator 40 used in the second embodiment. In the first embodiment, the positioning reference at the time of laminating the separator and the resin frame in the step 1 is the shape of the hole. Instead, in the second embodiment, the positioning reference is the outer peripheral shape, that is, the outer shape. It was. In addition, in the present embodiment, the reference outer shape portion is provided at three locations for both the resin frame 20 and the separator 40.

  In the resin frame 20, a first positive reference outer shape portion 130a and a second positive reference outer shape portion 130b are formed at one end of one short side in a plan view. Further, a first sub-reference outer shape portion 132a and a second sub-reference outer shape portion 132b are formed on one side from the center of one long side in plan view, and the first sub-reference outer shape portion 132b is formed on the other side from the center on the long side. One sub-reference outer shape portion 134a and a second sub-reference outer shape portion 134b were formed.

  Further, in the separator 40, similarly to the resin frame 20, the first positive reference outer shape portion 150 a and the second positive reference outer shape portion 150 b are formed at one end of one short side in a plan view. Further, a first sub-reference outer shape portion 152a and a second sub-reference outer shape portion 152b are formed on one side from the center on one long side in plan view, and the first sub-reference outer shape portion 152b is formed on the other side from the center on the long side. One sub-reference outer portion 154a and a second sub-reference outer portion 154b were formed.

  Each of the reference outer portions 130a to 134b provided on the resin frame 20 and each of the reference outer portions 150a to 154b provided on the separator 40 has a mountain shape (convex shape). Note that the first positive reference outer shape 130a, the first sub-reference outer shape 132a, and the first sub-second reference outer shape 134a on the resin frame 20 side are the first positive reference outer shape 150a on the separator 40 side, The heights are the same as those of the first sub-reference outline 152a and the first sub-reference outline 154a. On the other hand, the second positive reference outer shape portion 130b, the second sub-reference outer shape portion 132b, and the second sub-second reference outer shape portion 134b on the resin frame 20 side are the second positive reference outer shape portion 150b and the second sub-reference outer shape portion 134b on the separator 40 side. Compared with the second sub-reference outer shape portion 152b and the second sub-second reference outer shape portion 154b, they are lower by predetermined values γ, δ, and ε, which will be described later.

The dimensional relationship described above can be expressed as follows.
M1 = N1
M3 = N3
M5 = N5
M2 = N2-γ
M4 = N4-δ
M6 = N6-ε

here,
M1: Height of first positive reference outer shape portion 130a in resin frame 120 (FIG. 4) M2: Height of second positive reference outer shape portion 130b in resin frame 120 (FIG. 4) M3: Resin frame 120 (FIG. 4) ) M4: height of the second sub-reference outline 132b in the resin frame 120 (FIG. 4) M5: first sub-reference in the resin frame 120 (FIG. 4) Height of outer portion 134a M6: Height of second sub-reference outer shape portion 134b in resin frame 120 (FIG. 4) N1: Height of first positive reference outer shape portion 150a in resin frame 120 (FIG. 4) N2 : Height of second positive reference outline 150b in resin frame 120 (FIG. 5) N3: height of first sub reference outline 152a in resin frame 120 (FIG. 5) N4: tree Height of second sub-reference outline 152b in frame 120 (FIG. 5) N5: Height of first sub-reference outline 154a in resin frame 120 (FIG. 5) N6: In resin frame 120 (FIG. 5) Height γ of the second secondary reference outer shape portion 154b is a positive value, and the second positive reference outer shape portion 150b of the separator 40 is affected even when thermally deformed in consideration of expansion during curing. No dimension δ: Positive value, taking into account expansion at the time of curing, etc., a dimension that does not affect the second sub-reference outer shape 152b of the separator 40 even when thermally deformed ε: A positive value, Dimensions that do not affect the second secondary reference outer shape part 154b of the separator 40 even when thermally deformed in consideration of expansion during curing, etc.

  In step 1, in detail, the separator 140, the resin frame 120, and the separator 140 are stacked in this order to form a first regular reference outer shape portion 130a of the resin frame 120 and a first positive reference outer shape portion 150a of each separator 140. The second positioning plane is applied to the first sub-reference outer shape portion 132a of the resin frame 120 and the first sub-reference outer shape portion 152a of each separator 140, and the resin frame 120 is further applied. A third positioning plane is applied to each of the first sub-reference outer shape portion 134a and the first sub-reference outer shape portion 154a of each separator 140. In this state, the resin frame 120 and the separators 140 and 140 are thermocompression bonded. As a result, an assembly that is a laminate of the separator 140, the resin frame 120, and the separator 140 is created.

  In step 2, in detail, the assemblies created in step 1 are stacked, and the first positioning plane is applied to the second regular reference outer shape portion 150b of each separator 140 provided in each assembly, so that each assembly 100 A second positioning reference plane 152b is applied to the second sub-reference outer shape 152b of each separator 140 provided in the assembly 100, and a third positioning reference 154b of each separator 140 provided in each assembly 100 is used for the third positioning. Hit the plane. The second positive reference outer shape part 130b, the second sub-reference outer shape part 132b, and the second sub-second reference outer shape part 134b of the resin frame 20 are deformed by the thermocompression bonding process in step 1, It is not a standard for positioning. With each of the first to third positioning planes being applied, each assembly is thermocompression bonded. As a result, a laminate of each assembly 100 is created.

  As described above in detail, according to the method of manufacturing the fuel cell stack as the second embodiment, the second positive reference outer shape portion 130b, the second sub-reference outer shape portion 132b, and the second provided in the resin frame 120 are provided. The sub-second reference outer shape part 134b is lower by a predetermined value than the second positive reference outer shape part 150b, the second sub-reference outer shape part 152b, and the second sub-second reference outer shape part 154b provided in the separator 140. It has a shape that can cope with thermal deformation. For this reason, in Step 1, the resin does not protrude outside the second positive reference outer shape portion 130b, the second sub-reference outer shape portion 132b, and the second sub-reference outer shape portion 154b provided in the separator 140. .

  Therefore, in step 2, which is a subsequent step, each assembly 100 can be positioned using the second positive reference outer shape portion 130b, the second sub-reference outer shape portion 132b, and the second sub-second reference outer shape portion 154b. Therefore, the assembly can be stacked with high accuracy. As a result, according to the fuel cell stack manufacturing method of the second embodiment, as with the fuel cell stack manufacturing method of the first embodiment, the assembly accuracy of the fuel cell stack can be improved. . In addition, as in the first embodiment, there are secondary effects such as being able to select an inexpensive material, reducing process steps, and suppressing the occurrence of quality defects such as scratches.

C. Variation:
In the first embodiment, the reference hole is used for positioning in both steps 1 and 2, and in the second embodiment, the reference outer shape is used for positioning in both steps 1 and 2, but instead, in step 1, the reference outline is used. A configuration in which a hole is used and a reference outer shape portion is used in Step 2 or a reference outer shape portion is used in Step 1 and a reference hole is used in Step 2 may be used.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Moreover, elements other than the elements described in the independent claims among the constituent elements in the above-described embodiments and modifications are additional elements and can be omitted as appropriate.

DESCRIPTION OF SYMBOLS 10 ... Electric power generation body 20 ... Resin frame 21 ... Through-hole 28 ... Adhesive 30a ... 1st positive reference hole 30b ... 2nd positive reference hole 32a ... 1st secondary reference hole 32b ... 2nd secondary reference hole 40 ... Separator 41 ... Through hole 47 ... Groove channel 48 ... Sealant 50a ... First positive reference hole 50b ... Second positive reference hole 52a ... First sub reference hole 52b ... Second sub reference hole 100 ... Assembly 120 ... resin frame 130a ... first positive reference outline part 130b ... second positive reference outline part 132a ... first sub-reference outline part 132b ... second sub-reference outline part 134a ... first sub-reference outline part 134b ... second sub-reference outer shape 140 ... separator 150a ... first positive reference outer shape 150b ... second positive reference outer shape 152a ... first sub-reference outer shape 152b ... second sub-reference outer shape 154a ... First subgroup Outer portion 154b ... second sub s reference profile section

Claims (1)

A method for manufacturing a fuel cell stack, comprising:
A step of laminating a separator and a thermoplastic resin frame to create a battery assembly, the step of positioning the separator and the resin frame at the time of the lamination based on a first standard;
A step of stacking a plurality of the battery assemblies, wherein the positioning of the battery assemblies during the stacking is performed based on a second reference having a shape different from the first reference;
A method of manufacturing a fuel cell stack comprising:

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