Fuel cell stack and method of manufacturing fuel cell stack

Abstract

To well constrain the position of a cell stack without producing resin powder that adversely affects power generation performance.SOLUTION: A cell unit, which is stacked in a predetermined direction to form a cell stack, includes a membrane electrode assembly having a membrane electrode assembly and a resin film member supporting the membrane electrode assembly, a metal separator disposed opposite the membrane electrode assembly and having a positioning portion provided on its outer edge, and a resin reinforcing member attached to an exposed portion of the film member extending outward beyond the positioning portion. The reinforcing member includes a first positioned portion positioned by the positioning portion and a second positioned portion engaged or fitted with the positioning member, and the second positioned portion is provided to protrude outward beyond the outer edge of the film member.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a fuel cell stack and a method for manufacturing a fuel cell stack. [Background technology]

[0002] In recent years, technological developments have been made in fuel cells that contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy. A known technology related to fuel cell stacks used in this type of fuel cell is one in which a restraining member is provided between a cell stack and a case to restrain the position of the cell stack (see, for example, Patent Document 1). In Patent Document 1, a resin restraining member is placed in contact with the outer surface of the cell stack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6870603 Summary of the Invention [Problem to be solved by the invention]

[0004] However, because the edges of the separators, which are thin metal plates, are located on the outer surface of the cell stack, repeated contact between the cell stack and the restraining member due to external impact can wear the restraining member, potentially generating resin powder around the cell stack that can adversely affect power generation performance. [Means for solving the problem]

[0005] One aspect of the present invention is a fuel cell stack comprising a cell stack formed by stacking a plurality of cell units in a predetermined direction, a housing surrounding the cell stack, and a positioning member supported on the inner surface of the housing, extending in a predetermined direction, and regulating the position of the cell stack. The cell unit comprises a membrane electrode assembly having a membrane electrode assembly including an electrolyte membrane and electrodes, and a resin film member supporting the membrane electrode assembly, and a metal separator disposed opposite the membrane electrode assembly and having a positioning portion on its outer edge. The film member has an exposed portion extending outward beyond the positioning portion and exposed from the separator. The cell unit further comprises a resin reinforcing member adhered to the exposed portion. The reinforcing member has a first positioned portion positioned by the positioning portion and a second positioned portion engaged or fitted with the positioning member, the second positioned portion being located at the same position as the outer edge of the film member or protruding outward beyond the outer edge of the film member.

[0006] Another aspect of the present invention is a method for manufacturing a fuel cell stack including a cell stack formed by stacking a plurality of cell units in a predetermined direction, a housing surrounding the cell stack, and a positioning member supported on the inner surface of the housing, extending in a predetermined direction, and regulating the position of the cell stack, the method including a cell unit manufacturing process for manufacturing the cell units. The cell unit manufacturing process includes a joining process for joining a metal separator, which is disposed opposite the membrane electrode assembly and has a positioning portion on its outer edge, to the membrane electrode assembly, which includes a membrane electrode assembly including an electrolyte membrane and electrodes, and a resin film member supporting the membrane electrode assembly. The metal separator has a positioning portion on its outer edge, and the metal separator is positioned opposite the membrane electrode assembly, and the positioning portion is attached to an exposed portion of the film member that extends outward beyond the positioning portion and is exposed from the separator, while positioning the exposed portion with the positioning portion. The attaching process includes attaching the reinforcing member such that a positioned portion of the reinforcing member that engages or fits with the positioning member is positioned at the same position as the outer edge of the film member or protrudes outward beyond the outer edge of the film member. [Effects of the Invention]

[0007] According to the present invention, the position of the cell stack can be satisfactorily constrained without producing resin powder that adversely affects power generation performance. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing a schematic overall configuration of a fuel cell stack including a power generating cell according to an embodiment of the present invention; [Figure 2] 2 is a cross-sectional view showing the main configuration of the power generation region of a cell stack included in the fuel cell stack of FIG. 1. [Figure 3] FIG. 2 is an exploded perspective view of a unit cell included in the fuel cell stack of FIG. 1. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Figure 5] FIG. 5 is an enlarged view of a portion V in FIG. 4 showing an example of a reinforcing member. [Figure 6] 6 is a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] 5A to 5C are diagrams illustrating a reinforcing member bonding step included in the manufacturing process of the power generating cell. [Figure 8] FIG. 5 is a diagram showing a modification of FIG. 4. [Figure 9A] 5 is a plan view showing a configuration different from that of FIG. 4 of an integrated electrode assembly included in a power generating cell according to an embodiment of the present invention. [Figure 9B] FIG. 9B is a diagram showing a first modified example of FIG. 9A. [Figure 9C] FIG. 9B is a diagram showing a second modification of FIG. 9A. [Figure 9D] FIG. 9B is a diagram showing a third modified example of FIG. 9A. [Figure 10] FIG. 6 is a diagram showing an example of a reinforcing member different from that shown in FIG. 5. [Figure 11] 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] 5A to 5C are diagrams illustrating a bonding step of a reinforcing member. [Figure 13] FIG. [Figure 14] FIG. 11 is a diagram showing a modification of FIG. 10 . DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to Figs. 1 to 9D. A power-generating cell according to an embodiment of the present invention is included in a fuel cell stack, which is a main component of a fuel cell. The fuel cell is mounted, for example, in a vehicle and can generate electric power for driving the vehicle. The fuel cell can also be mounted in moving bodies other than vehicles, such as aircraft and ships, robots, and various industrial machines.

[0010] First, the overall configuration of the fuel cell stack will be described briefly. FIG. 1 is a perspective view showing the overall configuration of a fuel cell stack 100 according to an embodiment of the present invention. For convenience, the three mutually orthogonal axial directions shown in the figure are defined as the front-rear direction, the left-right direction, and the up-down direction, and the configuration of each part will be described in accordance with these definitions. These directions are not necessarily the same as the front-rear direction, the left-right direction, and the up-down direction of a vehicle. The front-rear direction in FIG. 1 is the stacking direction of the fuel cell stack 100, and when assembling the fuel cell stack 100, the stacking direction is aligned with the direction of gravity.

[0011] 1, the fuel cell stack 100 has a cell stack 10, end units 40 arranged at both front and rear ends of the cell stack 10, and a case 30 arranged around the cell stack 10, and has a generally rectangular parallelepiped shape as a whole. The length of the fuel cell stack 100 in the left-right direction is longer than the length in the up-down direction.

[0012] The case 30 has four generally rectangular side walls 300 that face the top, left, bottom, and right sides of the cell stack 10. These four side walls 300 form a generally box-shaped storage space SP0 that is open on the front and back. The case 30 is made of a metal such as aluminum or iron.

[0013] Part A of Fig. 1 shows a cutaway view of a side wall 300 of the case 30. As shown in part A of Fig. 1, the cell stack 10 has a plurality of power generating cells 1 (for convenience, only a single power generating cell 1 is shown) arranged in the storage space SP0.

[0014] The power-generating cell 1 has an integrated electrode assembly (UEA) 2 having a membrane electrode assembly including an electrolyte membrane and electrodes, and separators 3 arranged on both the front and rear sides of the integrated electrode assembly 2 and sandwiching the integrated electrode assembly 2. The integrated electrode assemblies 2 and separators 3 are arranged alternately in the front-to-rear direction. The integrated electrode assembly 2 can also be called a membrane electrode structure. A power-generating region that generates electricity through an electrochemical reaction between hydrogen and oxygen is formed in the center of the power-generating cell 1 in the left-to-right and up-to-down directions.

[0015] A plurality of guide members 45 (only some of which are shown) are interposed between the cell stack 10 and the side wall 300 of the case 30. The guide members 45 are rod- or plate-shaped members extending in the front-to-rear direction, and are attached in advance to the inner surface of the side wall 300. When assembling the fuel cell stack 100, for example, the rear end unit 40 is laid on its side, and a plurality of power-generating cells 1 guided by the guide members 45 are stacked on top of it to assemble the cell stack 10. Next, the front end unit 40 is mounted on top of the cell stack 10.

[0016] FIG. 2 is a cross-sectional view showing the main components of the power generation region of the cell stack 10, more specifically, a cross-sectional view taken along a plane extending in the vertical and front-rear directions. As shown in FIG. 2, the separator 3 has a pair of front and rear metal thin plates, a front plate 3F and a rear plate 3R, each of which has a corrugated cross section. The front plate 3F extends in the vertical and left-right directions and has a front surface 3Fa and a rear surface 3Fb. The rear plate 3R extends in the vertical and left-right directions and has a front surface 3Ra and a rear surface 3Rb. The opposing rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R are joined at their outer peripheral edges by welding or the like. This integrally joins the front plate 3F and the rear plate 3R to form the separator 3. The separator 3 is made of a conductive material with excellent corrosion resistance, such as stainless steel, titanium, or a titanium alloy.

[0017] A cooling flow path PAw through which a coolant flows is formed inside the separator 3 surrounded by the front plate 3F and the rear plate 3R, that is, between the rear surface 3Fb of the front plate 3F and the front surface 3Ra of the rear plate 3R. The flow of the coolant cools the power generation surface of the power generation cell 1. Water, for example, can be used as the coolant. The surface of the separator 3 facing the integrated electrode assembly 2 (the front surface 3Fa and the rear surface 3Rb) is formed unevenly by press molding or the like to form a gas flow path between the separator 3 and the integrated electrode assembly 2.

[0018] More specifically, an anode flow path PAa, through which a fuel gas containing hydrogen flows, is formed between the front surface 2a of the integrated electrode assembly 2 and the rear plate 3R of the separator 3 facing this front surface 2a. A cathode flow path PAc, through which an oxidant gas containing oxygen flows, is formed between the rear surface 2b of the integrated electrode assembly 2 and the front plate 3F of the separator 3 facing this rear surface 2b. The fuel gas and the oxidant gas are sometimes referred to as reactant gases without distinction. A compressive load F is applied to the cell stack 10 in the front-rear direction during assembly of the fuel cell stack 100. After assembly of the fuel cell stack 100 is complete, this compressive load F is maintained by fastening a pair of front and rear end units 40 to the case 30.

[0019] A single integrated electrode assembly 2 and a single separator 3 are integrated in advance by welding to form a unit cell (cell unit). Figure 3 is an exploded perspective view of a unit cell 1a showing the general configuration of the integrated electrode assembly 2 and separator 3. The unit cell 1a is formed, for example, by joining a pair of plates 3F, 3R to form the separator 3, and then overlapping the rear plate 3R of the separator 3 on the front surface 2a of the integrated electrode assembly 2. Although not shown in Figure 3, the integrated electrode assembly 2 and the separator 3 have positioning portions on their outer edges that are used to position them when they are welded.

[0020] As shown in FIG. 3, the integrated electrode assembly 2 includes a membrane electrode assembly (MEA) 20 and a resin film 21. The membrane electrode assembly 20 includes an electrolyte membrane, an anode electrode provided on the front surface of the electrolyte membrane, and a cathode electrode provided on the rear surface of the electrolyte membrane. The electrolyte membrane is, for example, a solid polymer electrolyte membrane. The anode electrode is formed on the front surface of the electrolyte membrane and includes an electrode catalyst layer that serves as a reaction field for electrode reactions, and a gas diffusion layer that is provided on the front surface of the electrode catalyst layer and diffuses and supplies fuel gas. The cathode electrode is formed on the rear surface of the electrolyte membrane and includes an electrode catalyst layer that serves as a reaction field for electrode reactions, and a gas diffusion layer that is provided on the rear surface of the electrode catalyst layer and diffuses and supplies oxidant gas.

[0021] At the anode electrode, fuel gas (hydrogen) supplied via the anode flow channel PAa (Fig. 2) and gas diffusion layer is ionized by the action of a catalyst and moves through the electrolyte membrane to the cathode electrode side. The electrons generated at this time pass through an external circuit and are extracted as electrical energy. At the cathode electrode, oxidant gas (oxygen) supplied via the cathode flow channel PAc (Fig. 2) and gas diffusion layer reacts with hydrogen ions introduced from the anode electrode and electrons transferred from the anode electrode, producing water. The produced water provides an appropriate humidity to the electrolyte membrane, and excess water is discharged outside the integrated electrode assembly 2.

[0022] The resin film 21 has a substantially rectangular shape, and its outer edge is formed by four sides (top side 211, left side 212, bottom side 213, and right side 214). The resin film 21 is made of an insulating resin material such as PPS (polyphenylene sulfide) or PEN (polyethylene naphthalate). A substantially rectangular opening 21a is provided in the center of the resin film 21. The membrane electrode assembly 20 is provided so as to cover the entire opening 21a, and the outer edge of the membrane electrode assembly 20 is supported by the resin film 21. On the left side of the opening 21a in the resin film 21, three through holes 201 to 203 are opened in a vertically aligned manner, penetrating the resin film 21 in the front-to-rear direction. On the right side of the opening 21a, three through holes 204 to 206 are opened in a vertically aligned manner, penetrating the resin film 21 in the front-to-rear direction.

[0023] The separator 3 has a generally rectangular shape overall, with four sides (top side 311, left side 312, bottom side 313, and right side 314) defining its outer periphery. The separator 3 has an uneven cathode flow path PAc (FIG. 2) and an uneven anode flow path PAa (FIG. 2) formed on its front and rear sides facing the membrane electrode assembly 20, respectively. The separator 3 has through-holes 301-306 that penetrate the separator 3 in the front-rear direction at positions corresponding to the through-holes 201-206 in the resin film 21. The through-holes 301-306 are connected to the through-holes 201-206 in the resin film 21, respectively. A collection of these mutually connected through-holes 201-206 and 301-306 forms a plurality of flow paths that penetrate the cell stack 10 and extend in the front-rear direction.

[0024] 1, the rear end unit 40 has a plurality of through holes 401 to 406 that penetrate the end unit 40 in the front-rear direction at positions corresponding to the through holes 201 to 206 and 301 to 306. Note that the front end unit 40 does not have the through holes 401 to 406.

[0025] A fuel gas tank storing high-pressure fuel gas is connected to through-hole 401 via an ejector, injector, etc., and the fuel gas is supplied to fuel cell stack 100 via through-hole 401, as shown by the solid arrow. This fuel gas is guided to anode flow path PAa via through-holes 201 and 301. After passing through anode flow path PAa, the fuel gas passes through through-holes 206 and 306 and is discharged from through-hole 406, as shown by the solid arrow.

[0026] An oxidant gas supply compressor is connected to through-hole 404, and as indicated by the dotted arrow, oxidant gas compressed by the compressor is supplied to fuel cell stack 100 via through-hole 404. This oxidant gas is guided to cathode flow path PAc via through-holes 204 and 304. After passing through cathode flow path PAc, the oxidant gas passes through through-holes 203 and 303 and is discharged from through-hole 403 as indicated by the dotted arrow.

[0027] A pump for supplying a cooling medium is connected to through-hole 405, and as shown by the dashed-dotted arrow, the cooling medium is supplied to fuel cell stack 100 through through-hole 405. This cooling medium is guided to cooling flow passage PAw between front plate 3F and rear plate 3R of separator 3 through through-holes 205 and 305. After passing through cooling flow passage PAw, the cooling medium passes through through-holes 202 and 302 and is discharged from through-hole 402 as shown by the dashed-dotted arrow.

[0028] The above is the general configuration of the fuel cell stack 100. This embodiment is characterized by the configuration of the outer edge of the integrated electrode assembly 2, particularly the configuration of the positioning portion. This point will be described below.

[0029] 4 is a cross-sectional view taken along line IV-IV in FIG. 1. FIG. 4 includes a rear view of the integrated electrode assembly 2. For convenience, in the following, including FIG. 4, only the outer edge of the resin film 21 of the integrated electrode assembly 2 is shown, and the membrane electrode assembly 20 and the through-holes 201-206 may be omitted. FIG. 4 shows a center point P, which is the center of the cell stack 10 in the left-right direction and the center in the up-down direction. Hereinafter, the side facing the center point P may be referred to as the inside, and the side away from the center point P may be referred to as the outside.

[0030] 4, a guide member 45 is interposed between the outer edge 21e of the resin film 21 of the integrated electrode assembly 2 and the inner wall surface 300a of the side wall 300 of the case 30. Specifically, a guide member 45 is interposed between the upper side 211 of the resin film 21 and the inner wall surface 300a, between the left side 212 and the inner wall surface 300a, and between the right side 214 and the inner wall surface 300a. A positioning portion 50 is provided on the outer edge 21e of the resin film 21, and the guide member 45 is fitted into the positioning portion 50.

[0031] The positioning portions 50 are provided at the left-right center of the upper side 211 of the resin film 21, the up-down center of the left side 212, and the up-down center of the right side 214. The positioning portions 50 may be provided in places other than the centers of the sides 211, 212, and 214. The positioning portion 50 may be provided on the lower side 213, and a guide member 45 may be interposed between the lower side 213 and the inner wall surface 300a. The multiple guide members 45 and positioning portions 50 have the same configuration.

[0032] Fig. 5 is an enlarged view of part V in Fig. 4. As shown in Fig. 5, guide member 45 has a base portion 451 having a substantially rectangular parallelepiped shape and a protruding portion 452 that protrudes inward (toward the right in Fig. 5) from base portion 451, and has a substantially T-shaped cross section. The cross-sectional shape of guide member 45 is constant over the entire length in the front-rear direction, and the front end and rear end of guide member 45 are each supported by end unit 40 of Fig. 1. Protruding portion 452 of guide member 45 is fitted into positioning portion 50.

[0033] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5. As shown in FIGS. 5 and 6, the positioning section 50 has a reinforcing member 51 attached to the front surface 21b of the resin film 21. The reinforcing member 51 is made of an insulating resin material. For example, it is made of the same material as the resin film 21. As shown in FIG. 5, the reinforcing member 51 has a substantially U-shape in plan view when viewed from the stacking direction (front-rear direction) and is disposed so as to overlap a recess 215 provided in the outer edge 21e of the resin film 21. The width W1 of the recess 510 of the reinforcing member 51 is smaller than the width W2 of the recess 215 of the resin film 21 and is the same as or substantially the same as (slightly smaller than) the width W0 of the protrusion 452 of the guide member 45. W1 may be equal to or smaller than W2, or W1 and W2 may be equal to each other.

[0034] The outer end (left end in FIG. 5 ) of the reinforcing member 51, i.e., the outer edge 51a, protrudes outward beyond the outer edge 21e of the resin film 21, and the entire recess 215 of the resin film 21 is covered by the reinforcing member 51. The outer edge 51a of the reinforcing member 51 and the outer edge 21e of the resin film 21 may be located at the same position. A predetermined gap is provided between the outer end face (left end face) of the reinforcing member 51 and the inner end faces (right end faces) of the base portion 451 and the protruding portion 452 of the guide member 45 that face the outer end face, and the reinforcing member 51 is disposed close to the guide member 45. The reinforcing member 51 may be disposed in contact with the guide member 45. That is, the gap may be zero.

[0035] As shown in FIG. 6, one end (outer edge 51a) of the reinforcing member 51 protrudes outward from the outer edge 3e of the separator 3, and the other end (inner edge 51b) is located inside the outer edge 3e of the separator 3. The resin film 21 to which the reinforcing member 51 is bonded is called the reinforcing film 22. The outer edge of the reinforcing film 22 forms a protruding portion 22a that protrudes outward from the outer edge 3e of the separator 3. The thickness of a first region AR1 of the reinforcing film 22 including the outer edge of this protruding portion 22a (outer edge 51a of the reinforcing member 51), i.e., the thickness of the reinforcing film 22 in the region where the reinforcing member 51 is provided, is thicker than the thickness of a second region AR2 inside the first region AR1, i.e., the thickness of the reinforcing film 22 in the region where the reinforcing member 51 is not provided.

[0036] In other words, the reinforcing film 22, which is a bonded body of the resin film 21 and the reinforcing member 51, has the reinforcing member 51 in the first region AR1 but does not have the reinforcing member 51 in the second region AR2. The thickness T1 of the reinforcing member 51 is thicker than the thickness T2 of the resin film 21. For example, the thickness T2 is 0.1 mm or less, and the thickness T1 is set within a range of more than 1 time but not more than 2 times, not more than 3 times, or not more than 5 times the thickness T2. However, the thickness T1 is not more than the height T0 of the rib portion 35 of the rear plate 3R of the separator 3, i.e., the height T0, which is the distance from the contact surface (front surface 21b) of the separator 3 that contacts the resin film 21 to a horizontal plane extending approximately parallel to the resin film 21. Therefore, the reinforcing member 51 that constitutes the thick portion of the reinforcing film 22 does not interfere with the separator 3.

[0037] The reinforcing member 51 can also be formed of a single or multiple U-shaped resin films 21. That is, the tip portion (first region AR1) of the reinforcing film 22 can also be configured by overlapping a single or multiple U-shaped resin films 21 on the resin film 21 to form two or more layers of the resin film 21.

[0038] The inner edge 51b of the reinforcing member 51 may be located at the same position as the outer edge 3e of the separator 3 in the left-right direction in FIG. 6, or may be located to the left of the outer edge 3e. This prevents interference between the reinforcing member 51 and the separator 3 regardless of the thickness of the reinforcing member 51, allowing the thickness T1 of the reinforcing member 51 to be greater than the height T0 of the rib portion 35 of the separator 3. The reinforcing member 51 can be attached to the front surface 21b of the resin film 21 in various ways. In this embodiment, the reinforcing member 51 is bonded via an adhesive. Because both the resin film 21 and the reinforcing member 51 are made of resin material, the two can be easily and satisfactorily bonded together using an adhesive.

[0039] The reinforcing member 51 is positioned and adhered to the resin film 21 using a manufacturing device. FIG. 7 is a perspective view showing a schematic configuration of the manufacturing device 400, and is a diagram mainly illustrating the adhesion process of the reinforcing member 51. The adhesion is performed by laying the integrated electrode assembly 2 on its side. Therefore, in the explanation of the adhesion process, the directions corresponding to the up-down direction and the front-back direction in FIG. 1 are defined as the front-back direction and the up-down direction, respectively, as shown in FIG. 7. The downward direction in the up-down direction in FIG. 7 corresponds to the direction of gravity.

[0040] 7, the manufacturing apparatus 400 has a table 410 on which the integrated electrode assembly 2 is placed, and a frame 420 mounted on an upper surface 411 of the table 410. The table 410 has a generally rectangular shape as a whole in a plan view from above, and the entire integrated electrode assembly 2 provided with the recess 215 is placed on the upper surface 411 of the table 410. A pair of guides 412 for regulating the position of the integrated electrode assembly 2 is provided on the upper surface 411 of the table 410 so as to protrude upward.

[0041] The guides 412 are, for example, plate members having a substantially L-shape in a plan view, and are provided corresponding to a pair of corners of the integrated electrode assembly 2. That is, the guides 412 protrude from the upper surface 411 of the table 410 corresponding to a right-hand front corner and a left-hand rear corner of the integrated electrode assembly 2. The pair of corners of the integrated electrode assembly 2 abut against the guides 412, thereby defining the relative position of the integrated electrode assembly 2 with respect to the table 410.

[0042] The frame 420 has a pair of parallel front and rear frame portions 421, 422 and a pair of left and right frame portions 423, 424, and has a generally rectangular frame shape in plan view. A pair of guides 413 that regulate the position of the frame 420 are further provided on the upper surface of the table 410 and protrude upward. The guides 413 are formed of plate members, for example, similar to the guides 412.

[0043] When the frame 420 is lowered, the frame 420 is lowered while a pair of corners are positioned by the guides 413, and the frame 420 is placed on the table. This defines the position of the frame 420 with respect to the table 410, in other words, the relative position of the frame 420 with respect to the integrated electrode assembly 2.

[0044] The inner edges of the frame portions 421, 422, and 424 are provided with protrusions 425 that protrude inward (toward the center point P) and correspond to the recesses 215 of the integrated electrode assembly 2. The protrusions 425 have the same or nearly the same shape as the protrusions 452 of the guide member 45, and when the frame 420 is placed on a table, the relative position of the protrusions 425 with respect to the integrated electrode assembly 2 is the same as the relative position of the protrusions 452 of the guide member 45 with respect to the integrated electrode assembly 2 in FIG. 4. Therefore, the protrusions 425 are located inside the recesses 215 of the integrated electrode assembly 2. The width W4 of the protrusions 425 is nearly equal to the width W1 of the recesses 510 of the reinforcing member 51. Strictly speaking, W4 is slightly smaller than W1.

[0045] After the frame 420 is mounted on the upper surface 411 of the table 410, the reinforcing member 51 is adhered to the resin film 21. That is, the reinforcing member 51 is adhered to the upper surface 21b (the front surface in FIG. 5) of the resin film 21 while the recessed portion 510 of the reinforcing member 51 is fitted into the protruding portion 425 of the frame 420 for positioning. This completes the adhering process.

[0046] The guide 412 for positioning the integrated electrode assembly 2 and the guide 413 for positioning the frame 420 may be integrally provided, or a single guide member may be used to position them. The guide 412 may protrude from the table 410 corresponding to the recess 215 rather than the corner of the resin film 21. The guide 413 may protrude from the table 410 corresponding to the protrusion 425 rather than the corner of the frame 420. The guides 412 and 413 may be substantially cylindrical pin-shaped. A member corresponding to the protrusion 425 of the frame 420 may be fixed in advance to a predetermined position on the top surface of the table. Alternatively, a bulge corresponding to the protrusion 425 may be provided on the top surface of the table in advance. This allows the reinforcing member 51 to be positioned without the frame 420 being used.

[0047] After the bonding step is completed, a welding step is performed to integrate the integrated electrode assembly 2 and the separator 3 by welding. In the welding step, the separator 3 is positioned by positioning portions provided on the frame 420. Although not shown, for example, a pair of protrusions that are approximately L-shaped in plan view and protrude inward from the corners of the inner edge of the frame 420 can be provided, and these can be used as positioning portions to position the pair of corners of the separator 3.

[0048] In this case, the separator 3 is lowered from above the frame 420 while being positioned along the positioning portion, and is mounted on the upper surface of the integrated electrode assembly 2. Then, using, for example, a laser processing machine, a laser beam is irradiated from above onto a predetermined welding portion to weld the upper surface of the resin film 21 (front surface 21b in FIG. 6) to the separator 3 (rear plate 3R). This produces a unit cell 1a (FIG. 3) in which the integrated electrode assembly 2 and separator 3 are integrated.

[0049] When assembling the fuel cell stack 100, the unit cells 1a are sucked by a robot hand (not shown). Then, the recesses of the unit cells 1a, i.e., the recesses 510 of the reinforcing members 51, are fitted into guide members 45 previously installed inside the case, and the unit cells 1a are positioned while stacking the unit cells 1a. This forms the cell stack 10. By stacking the unit cells 1a, the number of movements of the robot hand is reduced compared to when the integrated electrode assemblies 2 and the separators 3 are stacked separately, and the stacking process can be completed in a shorter time. Furthermore, it is the resin film 21 that is positioned by the guide members 45, and there is no need to position the separators 3 by the guide members 45.

[0050] A thick reinforcing member 51 is attached to the outer edge of the resin film 21, and the reinforcing member 51 protrudes outward beyond the outer edge 21e of the resin film 21. Therefore, when an external impact is applied to the fuel cell stack 100, the tip of the reinforcing member 51 abuts against the guide member 45. This suppresses movement of the cell stack 10 in directions perpendicular to the stacking direction (left-right and up-down directions in FIG. 1), effectively preventing the power generating cells 1 from shifting position.

[0051] That is, if the reinforcing member 51 were not bonded to the resin film 21, the leading edge of the thin resin film 21 would come into contact with the guide member 45 when an external impact is applied. This would cause the leading edge of the resin film 21 to deform, making it impossible to constrain the position of the cell stack 10. In contrast, when the reinforcing member 51 is bonded to the resin film 21 as in this embodiment, the rigidity of the leading edge of the reinforcing film 22 is increased. This prevents deformation of the leading edge of the resin film 21, and allows the position of the cell stack 10 to be constrained well.

[0052] In the above description, a plurality of reinforcing members 51 each having a substantially U-shape are adhered to the surface of the resin film 21 in correspondence with the recesses 215 of the resin film 21. However, the reinforcing members 51 may be configured to cover the entire outer edge of the resin film 21. FIG. 8 is a plan view showing an example of this. In FIG. 8, the reinforcing member 51 has a substantially rectangular outer edge 51a and inner edge 51b, and is configured in a frame shape along the outer edge 21e of the resin film 21. The outer edge 51a of the reinforcing member 51 is provided with a recess 510 similar to the reinforcing member 51 in FIG. 7, corresponding to the position of the guide member 45, and the guide member 45 is fitted into the recess 510. By configuring the reinforcing member 51 in this frame shape, the entire outer edge of the resin film 21 is reinforced, and the strength of the reinforcing film 22 can be further increased.

[0053] According to this embodiment, the following effects can be achieved. (1) The power-generating cell 1 includes an integrated electrode assembly 2 (membrane electrode structure) having a membrane electrode assembly 20 including an electrolyte membrane, an anode electrode, and a cathode electrode, and a resin film 21 supporting the membrane electrode assembly 20, and a metallic separator 3 disposed opposite the integrated electrode assembly 2 so as to form flow paths (anode flow path PAa, cathode flow path PAc) through which reactant gases flow between the integrated electrode assembly 2 and the resin film 2 (FIGS. 1 to 3). A resin reinforcing member 51 is bonded to the outer edge of the resin film 21 to form a reinforcing film 22 (FIG. 6). The reinforcing film 22 has a protruding portion 22a that protrudes outward beyond the outer edge 3e of the separator 3, and is configured so that a first region AR1 including the outer edge of the protruding portion 22a (the outer edge 51a of the reinforcing member 51) is thicker than a second region AR2 located inside the first region AR1 (FIG. 6).

[0054] According to this configuration, when the cell stack 10 and the guide member 45 repeatedly come into contact due to an external impact, the end of the resin reinforcing film 22 comes into contact with the guide member 45, rather than the separator 3 and the guide member 45. This makes it possible to prevent the generation of resin powder due to wear of the guide member 45. Furthermore, because the end of the reinforcing film 22 is thick, it has high rigidity and can prevent deformation of the end of the reinforcing film 22 when the reinforcing film 22 comes into contact with the guide member 45 due to an impact. As a result, it is possible to prevent displacement of the cell stack 10 and suppress leakage of the reactant gas, etc.

[0055] (2) The reinforcing film 22 has a reinforcing member 51 adhered to the surface of the resin film 21 (FIGS. 5 and 6). This makes it possible to easily increase the rigidity of the end portion of the resin film 21. In particular, the reinforcing member 51 has a generally U-shape corresponding to the guide member 45 and is adhered to the minimum necessary area of ​​the resin film 21, thereby reducing the manufacturing cost of the reinforcing member 51.

[0056] (3) The thickness T1 of the reinforcing member 51 is thicker than the thickness T2 of the resin film 21 (FIG. 6). The outer edge 51a of the reinforcing member 51 protrudes outward from the outer edge 21e of the resin film 21 or is located at the same position as the outer edge 21e (FIG. 5). This allows the end of the highly rigid reinforcing member 51 to reliably abut against the guide member 45, firmly restraining the position of the cell stack 10.

[0057] (4) The separator 3 is configured with an uneven shape (FIG. 2). The outer edge of the separator 3 extends approximately parallel to the surface of the resin film 21, at a predetermined height T0 from the surface (front surface 21b) of the resin film 21 (FIG. 6). The thickness T1 of the reinforcing member 51 is equal to or less than the predetermined height T0 (FIG. 6). This prevents the reinforcing member 51 from contacting the separator 3, and allows the inner edge 51b of the reinforcing member 51 to be positioned more inward than the outer edge 3e of the separator 3. This allows the overlapping area between the resin film 21 and the reinforcing member 51 to be increased, and the reinforcing member 51 can be easily and firmly bonded to the resin film 21.

[0058] (5) The fuel cell stack 100 includes a cell stack 10 formed by stacking the power-generating cells 1, each having the reinforcing film 22, in the front-rear direction, and a case 30 and end unit 40 that surround the cell stack 10 (FIG. 1). The resin film 21 has a generally rectangular shape (FIG. 3). The reinforcing member 51 is disposed adjacent to a guide member 45 provided on the inner wall surface 300a of the case 30 so as to restrict movement of the cell stack 10 along a plane perpendicular to the stacking direction of the power-generating cells 1 (FIGS. 5 and 6). This effectively prevents the cell stack 10 from shifting position when an external impact is applied to the fuel cell stack 10.

[0059] In the above, the reinforcing member 51 is used as an impact receiving portion that receives an external impact and as a positioning portion that positions the power generating cell 1, but the reinforcing member 51 may be used as an impact receiving portion and the power generating cell 1 may be positioned without the reinforcing member 51. FIGS. 9A to 9D are plan views of an integrated electrode assembly 2 showing one such example. Note that, in FIGS. 9A to 9D, illustrations of only the outer edge of the resin film 21 in the integrated electrode assembly 2 are omitted, as in FIG. 4 and the like.

[0060] 9A to 9D, a plurality of recesses 216 are provided in the outer edge 21e of the resin film 21. The recesses 216 are configured similarly to the recesses 510 in FIG. 5. Accordingly, a guide member 45 (not shown) is fitted into the recesses 215 to position the integrated electrode assembly 2 and the power generating cell 1. However, because the guide member 45 does not have a shock absorption function, it does not need to be configured to be thick like the guide member 45 in FIG. 5. In this case, the guide member 45 can be configured, for example, by a rod-shaped member having a substantially circular cross section.

[0061] 9A, reinforcing members 51A are bonded to the front surface 21b of the resin film 21 along four sides 211 to 214 of the resin film 21. The reinforcing members 51A are generally rectangular in plan view, and the entire reinforcing members 51A have a generally rectangular parallelepiped shape. The reinforcing members 51A are provided near the four corners of the resin film 21 so as to sandwich the four corners. In the configuration of FIG. 9A, the reinforcing members 51A are provided only where necessary, so that the material cost of the reinforcing members 51 can be reduced.

[0062] FIG. 9B is a first modified example of FIG. 9A. In FIG. 9B, reinforcing members 51B are adhered to the front surface 21b of the resin film 21 along the four corners of the resin film 21. The reinforcing members 51B are generally L-shaped in plan view and are provided to cover the entire corners. In the example of FIG. 9B, the rigidity of the entire corners is increased, allowing for better resistance to external impacts. Furthermore, the number of reinforcing members 51B can be reduced compared to that of FIG. 9A.

[0063] 9C is a second modified example of FIG. 9A. In FIG. 9C, reinforcing members 51C are bonded to the front surface 21b of the resin film 21 along a pair of short sides, that is, left side 212 and right side 214, of the resin film 21. Recesses 511 are provided in the outer edge 51a of the reinforcing members 51C, and recesses 216 of the resin film 21 are exposed through the recesses 511. Both longitudinal ends of the reinforcing members 51C abut against corners of the case 30. In the example of FIG. 9C, the number of reinforcing members 51C can be further reduced compared to that of FIG. 9B.

[0064] 9D shows a third modified example of FIG. 9A. In FIG. 9D, a single frame-shaped reinforcing member 51D is adhered to the front surface 21b of the resin film 21 along each of the sides 211 to 214 of the resin film 21. A recess 511 similar to that in FIG. 9C is provided at the outer edge of the reinforcing member 51D, and the recess 216 of the resin film 21 is exposed through the recess 511. The reinforcing member 51D covers the entire outer edge 21e of the resin film 21, thereby increasing the overall rigidity of the resin film 21.

[0065] In the above, the manufacturing apparatus 400 is used to position the reinforcing member 51 while adhering it to the surface of the resin film 21 (FIG. 7). That is, the recessed portion 520 of the reinforcing member 51 is fitted into the protruding portion 425 of the frame 420 to position the reinforcing member 51. However, preparing the frame 420 is costly. Therefore, in order to position the reinforcing member inexpensively, a positioning portion for the reinforcing member can be provided on the separator 3. This point will be described below with reference to FIGS. 10 to 14.

[0066] FIG. 10 is a cross-sectional view of a main part of a fuel cell stack 100, showing the configuration of a reinforcing member 52 positioned on a separator 3. FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. 10. FIG. 12 is an exploded perspective view of a unit cell 1a included in FIG. 10. Note that FIG. 10 corresponds to FIG. 5, with the reinforcing member 51 in FIG. 5 replaced with a reinforcing member 52. FIG. 12 shows the bonding process of the reinforcing member 52. Therefore, the direction of gravity is downward, as in FIG. 7.

[0067] As shown in Figures 10 and 12, a concave cutout 36 is provided in the outer edge 3e of the separator 3. The cutout 36 has a pair of side surfaces 36a facing each other and a bottom surface 36b at the back of the cutout 36. The pair of side surfaces 36a are parallel to each other. The resin film 21 protrudes outward beyond the separator 3 (to the left in Figure 10) and has an exposed portion 26 exposed from the separator 3 inside the cutout 36. A resin reinforcing member 52 is bonded to the exposed portion 26 via an adhesive. This forms the reinforcing film 22 as shown in Figure 11. The thickness T1 of the reinforcing member 52 is thicker than the thickness T2 of the resin film 21, for example, as in Figure 6.

[0068] As shown in FIG. 10 , the reinforcing member 52 has a generally U-shape in plan view from the stacking direction of the power-generating cells 1. The width of the reinforcing member 52 (the length in the vertical direction in FIG. 10 ) is equal to the width of the notch 36. The reinforcing member 52 has contact portions 56 at both ends in the width direction, and the contact portions 56 contact the side surfaces 36 a of the notches 36. The length of the reinforcing member 52 (the length in the horizontal direction in FIG. 10 ) is longer than the depth of the notches 36 (the length in the horizontal direction in FIG. 10 ). Therefore, the reinforcing member 52 extends beyond the notches 36 in the horizontal direction in FIG. 10 . That is, the outer end (outer edge 52 a) of the reinforcing member 52 extends leftward in FIG. 10 beyond the outer edge 3 e of the separator 3, and the inner end extends rightward in FIG. 10 beyond the bottom surface 36 b of the notches 36.

[0069] 11, the inner end portion (the right end portion in FIG. 11) of reinforcing member 52 has a stepped shape and includes thick portion 525 bonded to resin film 21 and thin portion 526 on the inner side (right side) of thick portion 525. Thin portion 526 extends approximately parallel to resin film 21 so as not to interfere with separator 3, and separator 3 is located between thin portion 526 and resin film 21. There is a gap between inner end surface 525a of thick portion 525 and bottom surface 36b of notch 36 in separator 3. Note that inner end surface 525a and bottom surface 36b may abut without a gap.

[0070] As shown in FIG. 10, the outer edge 52a of the reinforcing member 52 and the outer edge 21e of the resin film 21 are located at the same position in the left-right direction. The outer edge 52a may protrude outward (to the left in FIG. 10) from the outer edge 21e. A recess 27, similar to the recess 215 in FIG. 5, is provided in the outer edge 21e of the resin film 21 at the center of the exposed portion 26. As shown in FIGS. 10 and 12, a recess 55 is provided in the center in the width direction of the outer edge 52a of the reinforcing member 52. The width W10 of the recess 55 is narrower than the width W20 of the recess 27. Therefore, the edge of the recess 55 protrudes outward from the edge of the recess 27 (to the inside of the recess 27), and the entire recess 27 is covered by the recess 55. The width W20 of the recess 27 may be the same as the width W10 of the recess 55.

[0071] The width W10 of the recess 27 is equal to or approximately equal to the width W0 of the protrusion 452 of the guide member 45. Therefore, the recess 55 is fitted into the protrusion 452. This positions the individual power generating cells 1 of the fuel cell stack 100, in other words, the unit cells 1a, and restricts movement of the cell stack 10 within the case 30.

[0072] The method for manufacturing a fuel cell stack 100 includes a cell manufacturing process (cell unit manufacturing process) for manufacturing a unit cell 1a. In the cell manufacturing process, the unit cell 1a of FIG. 12 is manufactured as follows. First, the resin film 21 of the integrated electrode assembly 2 is bonded to the separator 3 in advance (bonding process). More specifically, after the integrated electrode assembly 2 is positioned and placed on a processing table (not shown), the separator 3 is positioned and placed on the upper surface of the integrated electrode assembly 2. Then, the separator 3 is welded to the resin film 21 at predetermined welding portions, such as corners of the separator 3.

[0073] FIG. 13 is a cross-sectional view of a unit cell 1a illustrating the welding process. As shown in FIG. 13, a substantially circular through-hole 3c is pre-opened in the front plate 3F of the separator 3 facing the weld portion 25. A substantially cylindrical jig 430 is inserted from above through the through-hole 3c, and the jig 430 presses the rear plate 3R so that the rear plate 3R and the resin film 21 are tightly attached to each other. Note that the jig 430 can be omitted. A laser beam LB is irradiated onto the weld portion 25 using a laser processing machine attached to the hand of a robot (not shown). That is, the laser beam LB is irradiated from above the separator 3 toward the rear plate 3R through the through-hole 3c, as indicated by the arrow. This heats the weld portion 25, melting a portion of the resin film 21, and welding the rear plate 3R of the separator 3 and the resin film 21 together at the weld portion 25.

[0074] After the welding step (bonding step) is completed, the reinforcing member 52 is attached to the upper surface of the resin film 21 (attaching step). That is, the reinforcing member 52 is attached to the exposed portion 26 of the resin film 21 using an adhesive. Specifically, the reinforcing member 52, which is held by the hand of a robot (not shown), is fitted into the notch 36 of the separator 3, and the pair of abutting portions 56 are abutted against the side surfaces 36a of the notch 36 to position the reinforcing member 52, and the reinforcing member 52 is attached. This makes it possible to easily and accurately attach the reinforcing member 52 to the upper surface of the thin resin film 21. This completes the production of the unit cell 1a.

[0075] When assembling the fuel cell stack 100, a unit cell 1a is picked up by a robot hand (not shown), and the recesses 55 of the reinforcing members 52 are fitted into the guide members 45 previously installed inside the case, and multiple unit cells 1a are stacked while positioning the unit cells 1a. This forms the cell stack 10. Thereafter, a compressive load F (FIG. 2) is applied to the cell stack 10 to fasten the end units 40 to the case 30, thereby completing the manufacture of the fuel cell stack 100.

[0076] In Fig. 10, the pair of side surfaces 36a, 36a of the cutout 36 in the separator 3 are parallel to each other, but the pair of side surfaces 36a, 36a may be non-parallel. Fig. 14 shows an example. In Fig. 14, the pair of side surfaces 36a, 36a are inclined at a predetermined angle with respect to a reference line CL0 that passes through the center of the cutout 36 and extends from the inside to the outside, and extend symmetrically with each other. In other words, the cutout 36 is formed to be an isosceles trapezoid in a plan view.

[0077] Corresponding to the shape of the notch 36, the pair of abutment portions 56, 56 of the reinforcing member 52 are also formed to be inclined at the same inclination angle as the pair of side surfaces 36a, 36a. As a result, by pressing the reinforcing member 52 against the bottom surface 36b of the notch 36, the pair of side surfaces 36a, 36a and the pair of abutment portions 56, 56 abut against each other without any gaps. Therefore, the reinforcing member 52 can be well-positioned by the notch 37 without any rattle.

[0078] According to this embodiment, the following effects can be further achieved. (1) A fuel cell stack 100 includes a cell stack 10 formed by stacking a plurality of unit cells 1a in the front-rear direction, a case 30 surrounding the cell stack 10, and a guide member 45 supported by an inner wall surface (inner surface) 300a of the case 30, extending in the front-rear direction, and regulating the position of the cell stack 10 ( FIGS. 1 and 4 ). Each unit cell 1a includes an integrated electrode assembly 2 (membrane electrode structure) having a membrane electrode assembly 20 including an electrolyte membrane, an anode electrode, and a cathode electrode, and a resin film 21 supporting the membrane electrode assembly 20, and a metal separator 3 disposed opposite the integrated electrode assembly 2 and having a notch 36 formed in an outer edge 3e ( FIGS. 10 and 12 ). The resin film 21 extends outward beyond the notch 36 and has an exposed portion 26 exposed from the separator 3 ( FIGS. 10 and 12 ). The unit cell 1a further has a reinforcing member 52 made of resin that is adhered to the exposed portion 26 (FIGS. 10 to 12). The reinforcing member 52 has a contact portion 56 that is positioned by the notch 36, and a recess 55 that fits into the guide member 45 (FIGS. 10 and 12). The edge of the recess 55 is located in the same position as the outer edge 21e of the resin film 21, or protrudes outward beyond the outer edge 21e of the resin film 21 (FIG. 10).

[0079] With this configuration, when the cell stack 10 and the guide member 45 repeatedly come into contact due to an external impact, the end of the resin reinforcing member 52 comes into contact with the guide member 45, rather than the separator 3 and the guide member 45. This prevents the generation of resin powder due to wear of the guide member 45. Furthermore, the end of the reinforcing member 52 is thick and therefore highly rigid. This prevents deformation of the end of the reinforcing film 22, which is a bonded body of the resin film 21 and the reinforcing member 52, when the reinforcing film 22 comes into contact with the guide member 45 due to an impact. As a result, displacement of the cell stack 10 is prevented, and leakage of the reaction gas, etc., can be suppressed. Furthermore, the reinforcing member 52 is positioned by the cutout 36 of the separator 3, allowing the reinforcing member 52 to be easily and accurately bonded to the thin resin film 21.

[0080] (2) The notch 36 is formed in a concave shape on the outer edge 3e of the separator 3 (FIG. 12). The reinforcing member 52 (contact portion 56) is formed to fit into the notch 36 (FIGS. 10 and 12). This allows the pair of contact portions 56, 56 of the reinforcing member 52 to contact the pair of side surfaces 36a, 36a of the notch 36, making it easy to position the reinforcing member 52.

[0081] (3) The notch 36 has a pair of parallel side surfaces 36a, 36a or a pair of non-parallel side surfaces 36a, 36a that form a recess (FIGS. 10 and 13). In particular, when the notch 36 has a pair of non-parallel side surfaces 36a, 36a, the entire surface of the abutting portion 56 can abut against the side surfaces 36a, and the reinforcing member 52 can be positioned by the notch 37 without rattle.

[0082] (4) The reinforcing member 52 is made of the same material as the resin film 21 and is adhered to the exposed portion 26 (FIGS. 10 and 11). This makes it easy to adhere the reinforcing member 52 and ensures sufficient adhesive strength.

[0083] (5) A method for manufacturing a fuel cell stack, which manufactures a fuel cell stack 100 having a cell stack 10 formed by stacking a plurality of unit cells 1a in a predetermined direction, a case 30 surrounding the cell stack 10, and a guide member 45 supported by an inner wall surface (inner side surface) 300a of the case 30, extending in the front-to-rear direction, and regulating the position of the cell stack 10, includes a unit cell manufacturing process (cell unit manufacturing process) for manufacturing the unit cells 1a (Figures 1 and 4). The unit cell manufacturing process includes a joining process (i.e., welding process) of joining a metal separator 3, which is disposed opposite the integrated electrode assembly 2 and has a notch 36 formed in its outer edge 3e, to an integrated electrode assembly 2 having a membrane electrode assembly 20 including an electrolyte membrane, an anode electrode, and a cathode electrode, and a resin film 21 supporting the membrane electrode assembly 20, and an adhering process (sticking process) of adhering a resin reinforcing member 52 to an exposed portion 26 of the resin film 21, which extends outward beyond the notch 36 and is exposed from the separator 3, while positioning the reinforcing member 52 using the notch 36 ( FIG. 12 ). The adhering process includes adhering the reinforcing member 52 in a state in which a recess 55, which is formed in the reinforcing member 52 so as to fit into the guide member 45, is positioned at the same position as the outer edge 21e of the resin film 21 or protrudes outward beyond the outer edge 21e of the resin film 21 ( FIG. 10 ). As a result, the end of the resin reinforcing film 22 abuts against the guide member 45, preventing the generation of resin powder due to wear of the guide member 45, and by adhering the highly rigid reinforcing member 52, deformation of the end of the reinforcing film 22 when an impact is applied can be suppressed. Furthermore, the reinforcing member 52 is positioned by the notch 36 of the separator 3, making it easy to adhere the reinforcing member 52.

[0084] The above embodiment can be modified in various ways. Several modifications will be described below. In the above embodiment, the reinforcing member 52 is fitted into the notch 36 provided in the outer edge 3e of the separator 3, but the configuration of the positioning portion is not limited to that described above. That is, the positioning portion may be formed in a convex shape rather than a concave shape. Therefore, the abutting portion (first positioned portion) of the reinforcing member 52 is also not limited to that described above, and may be formed in a concave shape rather than a convex shape. In the above embodiment, the recess 55 is provided in the reinforcing member 52 so as to fit into the guide member 45, but the configuration of the second positioned portion is not limited to that described above. That is, the second positioned portion may have any configuration as long as it is positioned by engaging or fitting into the guide member 45.

[0085] In the above embodiment, the reinforcing member 52 is adhered to the resin film 21 as a film member, but the reinforcing member may be attached without using an adhesive. In the above embodiment, the thickness T1 of the reinforcing member 52 is greater than the thickness T2 of the resin film 21, but the thickness T1 may be the same as or less than the thickness T2. In the above embodiment, the reinforcing member 51 is formed from a single member, but the reinforcing member 51 may be formed by overlapping multiple film members. For example, if the thickness T1 of the reinforcing member 51 is greater than the thickness of the resin film 21, the reinforcing member 51 may be formed by overlapping multiple resin films 21 configured in a substantially U-shape.

[0086] In the above embodiment, the cell stack 10 was formed by stacking multiple power generating cells 1 in the front-rear direction (a predetermined direction), but the stacking direction is not limited to the front-rear direction. In the above embodiment, the cell stack 10 was surrounded by the case 30 and the end unit 40, but the configuration of the housing is not limited to that described above. In the above embodiment, the guide member 45 was formed with a generally T-shaped cross section, but the positioning member may have any configuration as long as it is supported by the inner surface of the housing, extends in a predetermined direction, and regulates the position of the cell stack 10. In the above embodiment, the reinforcing member 52 was made of the same material as the resin film 21, but it may be made of a different material.

[0087] The above description is merely an example, and the present invention is not limited to the above-described embodiment and modifications as long as the features of the present invention are not impaired. One or more of the above-described embodiment and modifications can be arbitrarily combined, and modifications can also be combined with each other.

[0088] 1a unit cell, 2 integrated electrode assembly, 3 separator, 3e outer edge, 10 cell stack, 20 membrane electrode assembly, 21 resin film, 21e outer edge, 22 reinforcing film, 26 exposed portion, 30 case, 36 notch, 36a side surface, 40 end unit, 45 guide member, 52 reinforcing member, 52a outer edge, 55 recess, 56 abutting portion, 100 fuel cell stack, 300a inner surface

Claims

1. a cell stack formed by stacking a plurality of cell units in a predetermined direction; a housing that surrounds the cell stack; a positioning member supported on an inner surface of the housing, extending in the predetermined direction, and regulating the position of the cell stack, The cell unit comprises: a membrane electrode structure including a membrane electrode assembly including an electrolyte membrane and an electrode, and a resin film member supporting the membrane electrode assembly; a metallic separator disposed opposite the membrane electrode assembly and having a positioning portion on its outer edge, the film member has an exposed portion that extends outward beyond the positioning portion and is exposed from the separator, the cell unit further includes a reinforcing member made of resin and attached to the exposed portion, the reinforcing member has a first positioned portion that is positioned by the positioning portion and a second positioned portion that is engaged with or fitted to the positioning member, The fuel cell stack according to claim 1, wherein the second positioned portion is provided at the same position as an outer edge of the film member or protrudes outward from the outer edge of the film member.

2. 2. The fuel cell stack according to claim 1, the positioning portion is formed in a concave or convex shape on the outer edge of the separator, The fuel cell stack according to claim 1, wherein the first positioned portion is formed to fit into the positioning portion.

3. 3. The fuel cell stack according to claim 2, The positioning portion has a pair of non-parallel side surfaces that form a recess or a protrusion.

4. The fuel cell stack according to any one of claims 1 to 3, The fuel cell stack is characterized in that the reinforcing member is made of the same material as the film member and is adhered to the exposed portion.

5. 1. A method for manufacturing a fuel cell stack, the method comprising: manufacturing a fuel cell stack having a cell stack formed by stacking a plurality of cell units in a predetermined direction; a housing surrounding the cell stack; and a positioning member supported on an inner surface of the housing, extending in the predetermined direction, and regulating the position of the cell stack, the method comprising: a cell unit manufacturing step of manufacturing the cell unit, The cell unit manufacturing process includes: a joining step of joining a metallic separator, which is disposed opposite the membrane electrode assembly and has a positioning portion provided on its outer edge, to a membrane electrode assembly having a membrane electrode assembly including an electrolyte membrane and an electrode and a resin film member supporting the membrane electrode assembly; and a bonding step of bonding a resin reinforcing member to an exposed portion of the film member that extends outward beyond the positioning portion and is exposed from the separator while positioning the reinforcing member using the positioning portion, A method for manufacturing a fuel cell stack, characterized in that the attachment process includes attaching the reinforcing member in a state where a positioned portion of the reinforcing member that is provided to engage or fit with the positioning member is positioned at the same position as the outer edge of the film member or protrudes outward beyond the outer edge of the film member.

Images