Fuel cell and method for producing a fuel cell

Abstract

Fuel cell, comprising: a cell stack (100) in which a plurality of unit cells are stacked; a housing (300) which accommodates the cell stack; and a pressure plate (200) arranged in the housing at a position between one end of the cell stack (100) in the stacking direction and the housing (300); wherein the housing has a first opening (322) through which a pressing element (120) pressing on the pressure plate from outside the housing in the stacking direction is brought into contact with the pressure plate, and a fixing portion (500) which fixes the pressure plate in this position with the cell stack compressed in the stacking direction, wherein the fuel cell is characterized in that the fixing portion (500) has an internally threaded portion provided in the housing such that it faces the pressure plate in the stacking direction, and a screw member (500) having a proximal end connected to the internally threaded portion and a distal end in contact with the pressure plate, and a position of the first opening (322) in the housing and a position of the fixing portion (500) in the housing differ from each other.

Description

Background of the invention 1. Field of the invention

[0001] The present invention relates to a fuel cell and a method for producing a fuel cell. 2. Description of the state of the art

[0002] Generally, a fuel cell is known in which a cell stack in which a plurality of cells are stacked is housed in a box-shaped casing. In many cases, the cell stack is compressed in the stacking direction or held under pressure in the casing. Generally, each cell includes a membrane electrode assembly in which a pair of electrodes are arranged on both sides of an electrolyte, and a pair of separators are arranged on both sides of the membrane electrode assembly.

[0003] As a method for adjusting the compressive load in the stacking direction applied to the cell stack housed in the casing of a fuel cell, JP 2002-358985 A discloses a method for adjusting the compressive load on the cell stack by turning bolts from outside the casing to adjust the axial forces of the bolts. JP 2005-524214 A discloses a method for adjusting the compressive load by inserting washers (spacer plates) between the casing and the cell stack.

[0004] However, in the case of the method of adjusting the compression load by adjusting the axial forces of bolts, the cell stack is compressed by stress from the bolts, and the stress cannot be evenly applied to the entire surface of the cell stack. In addition, chips may be generated when the bolts are screwed in. On the other hand, in the case of the method of adjusting the compression load by inserting washers, the weight of the fuel cell increases due to the weight of the washers, and it is difficult to finely adjust the compression load by changing the thickness or number of washers. As described above, there is still room for improvement in the methods of adjusting the compression load on a cell stack housed in a casing in a fuel cell.

[0005] Furthermore, JP 2002-056883 A discloses a fuel cell device comprising a fuel cell stack, current collecting plates, insulating plates, and pressure plates provided on both sides of the fuel cell stack. Spring pins with spring elements at the front end press on the pressure plates.

[0006] JP H10-189025 A discloses a fuel cell in which a stack is stored in a stack receiving opening formed in a casing. An insulating plate, on which a certain number of individual cells are laminated, is arranged at one end portion of the stack. A pressure plate with four plate guides is laminated on the outer surface of the insulating plate. Four rail members, parallel to the stacking direction, are attached to the side surface in the stack receiving opening. When the pressure plate is laminated, the rail members are engaged with the corresponding plate guides to insert the pressure plate.

[0007] US 2009 / 0 004 533 A1 describes a mechanism for applying a tension load, comprising a plurality of disc springs for applying a load in a stacking direction to a stacked body, a plurality of guide rods extending in the stacking direction, and a plurality of bearing elements between a movable pressure plate and an end plate. The guide rods are slidably inserted into the bearing elements in the stacking direction.

[0008] Each of the bearing elements has a housing attached to the end plate and a bearing mounted on the housing. The guide rod is attached to the bearing for sliding movement in the stacking direction.

[0009] JP H11-97054 A discloses a fastening mechanism comprising a pressure plate that is mounted between at least one of end plates and a laminated body and presses the laminated body; support rods whose base edge portions are fixed to the pressure plate and whose tip edge portions protrude from through holes formed in the end plate and are movable in the through holes of the end plate to support the pressure plate; elastic members that are mounted between the end plate and the pressure plate and have elasticity to be compressed; and locking members that are mounted on the tip end portions of the support rods to hold the elastic members in a predetermined compressed state. The locking members are located at the locations where the elastic members are held in a predetermined compressed state.

[0010] EP 1 094 536 A1 discloses an electrochemical fuel cell stack having an upper endplate assembly, a lower endplate assembly, at least one electrochemical fuel cell assembly disposed between the upper and lower endplate assemblies, and a clamping mechanism that clamps the stack under pressure. The upper endplate assembly includes a manifold plate overlying the fuel cell assembly and pressed against the fuel cell assembly by the clamping mechanism; an upper endplate overlying the manifold plate and pressed against the manifold plate by the clamping mechanism; and a plurality of screws threaded through threaded holes in the upper endplate at spaced locations in the upper endplate and having their lower ends abutting an upper surface of the manifold plate.The screws are tightened selectively to produce a substantially uniform torque on each screw.

[0011] Furthermore, JP 2002-63929 A discloses a stacked structure of a fuel cell, wherein a pair of end plates and a cell stack sandwiched and clamped between the end plates are arranged in a space formed by an endless belt body. A plurality of set screws are attached to an upright portion of the belt body, and the inner end of the set screws abuts the end plate. The outer end of the set screw protrudes from the upright portion, and a nut is threadably engaged therewith. When the nut is rotated, the set screw is screwed back and forth, and the pressure for the cell stack changes. Summary of the invention

[0012] The present invention provides a technology that simplifies the manufacture of a fuel cell in which a cell stack is held compressed in the stacking direction in a housing.

[0013] The above problems and the resulting object are solved by the subject matter of claims 1, 3 and 9. Advantageous developments of the invention are the subject matter of the subsequent dependent claims.

[0014] A fuel cell according to a first explanatory aspect of the present disclosure includes a cell stack in which a plurality of unit cells are stacked, a casing that accommodates the cell stack, and a pressure plate disposed in the casing at a position between one end of the cell stack in the stacking direction and the casing, and the casing has a first opening through which a pressing member pressing the pressure plate from outside the casing in the stacking direction is brought into contact with the pressure plate, and a fixing portion that fixes the pressure plate in this position with the cell stack compressed in the stacking direction.

[0015] With this configuration, the pressure plate can be pressed from outside the housing through the first opening in the stacking direction, and the pressure plate can be fixed in this position and held compressed in the stacking direction by means of the fixing portion. Therefore, a fuel cell in which a cell stack is held compressed in the stacking direction in a housing can be easily manufactured.

[0016] In the fuel cell according to the above aspect, the first opening may be opposite to the pressure plate in the stacking direction.

[0017] This configuration allows easy pressing of the printing plate from outside the housing, as the first opening of the printing plate is opposite in the stacking direction.

[0018] In the fuel cell according to the above aspect, the fixing portion may include an internally threaded portion provided in the casing so as to be opposed to the pressure plate in the stacking direction, and a screw member having a proximal end connected to the internally threaded portion and a distal end in contact with the pressure plate.

[0019] This configuration provides a simple way to prevent the pressure plate from moving against the tension of the compressed cell stack.

[0020] A fuel cell according to a second explanatory aspect of the present disclosure includes a cell stack in which a plurality of unit cells are stacked, a casing accommodating the cell stack, and a pressure plate disposed in the casing at a position between one end of the cell stack in the stacking direction and the casing, and the casing has at least a first opening and a second opening each having different opening areas, which are opposed to the pressure plate in the stacking direction.

[0021] With this configuration, the pressure plate can be pressed from outside the casing in the stacking direction through one opening, and the pressure plate can be fixed in position and compressed in the stacking direction through the other opening. Therefore, a fuel cell in which a cell stack is compressed in the stacking direction within a casing can be easily manufactured.

[0022] In the fuel cell according to the above aspect, the number of the first opening(s) having a larger opening area than the second opening is one to three.

[0023] With the help of this configuration, the pressing element can be easily pressed onto the printing plate from outside the housing through the first opening or openings in the stacking direction.

[0024] In the fuel cell according to the above aspect, the number of the first openings may be two or three, and the first openings may be positioned such that the center of gravity of the cell stack (the center of gravity of the unit cells) is located between the two first openings or in a region surrounded by the three first openings when viewed from the stacking direction.

[0025] With this configuration, the resulting force of the forces applied by the pressing elements to the pressure plate can be applied at a point close to the center of gravity of the cell stack (the center of gravity of the unit cells) when pressing on the pressure plate from outside the housing through the first openings in the stacking direction. Therefore, the pressure plate can be easily pressed in the stacking direction.

[0026] In the fuel cell according to the above aspect, the number of the first opening may be one, and the first opening may be arranged at a position opposite to the center of gravity of the cell stack (the center of gravity of the unit cells) from the stacking direction.

[0027] With this configuration, the pressure plate can be pressed at a point close to the center of gravity of the cell stack (the center of gravity of the unit cells) by pressing the pressure plate in the stacking direction from outside the housing through the first opening. Therefore, the pressure plate can be easily pressed in the stacking direction.

[0028] In the fuel cell according to the above aspect, the first opening may be used to bring a pressing member, which is used to press the pressure plate from outside the casing in the stacking direction, into contact with the pressure plate.

[0029] In the fuel cell according to the above aspect, the second opening, which has a smaller opening area than the first opening, may have a thread groove at an inner periphery of the second opening.

[0030] Using this configuration, the pressure plate can be easily fixed in this position by attaching screw elements to the internal thread sections.

[0031] A method of manufacturing a fuel cell according to a third explanatory aspect of the present disclosure includes preparing a cell stack in which a plurality of unit cells are stacked and a casing used to house the cell stack, arranging the cell stack in the casing so that one end of the cell stack in the stacking direction faces the casing via a pressing plate, compressing the cell stack in the casing in the stacking direction by pressing the pressing plate from outside the casing by means of a pressing member, and fixing the pressing plate in this position with the cell stack compressed by the pressing member.

[0032] With this configuration, the pressure plate is fixed in position after the cell stack is compressed from outside the casing. Therefore, a fuel cell can be easily manufactured in which a cell stack is held under pressure in the stacking direction.

[0033] In the manufacturing method according to the above aspect, the case may have at least two types of openings through a side wall of the case, the cell stack may be arranged in the case such that one end of the cell stack in the stacking direction is opposite to the side wall via the pressure plate, the cell stack may be compressed by pressing the pressure plate in the stacking direction from outside the case through a first opening of the side wall using a pressing member, and the pressure plate may be fixed by attaching a screw member between the pressure plate and a second opening of the side wall.

[0034] With this configuration, the pressure plate is fixed in position by attaching the screw member between the pressure plate and the second opening, while the cell stack is compressed from outside the casing through the first opening. Therefore, a fuel cell in which a cell stack is held under pressure in the stacking direction can be easily manufactured.

[0035] In the manufacturing method according to the above aspect, the pressure plate can be fixed by attaching the screw member when the compression load applied to the cell stack by pressing the pressing member reaches a predetermined value, and the pressing force of the pressing member can be released after the screw member is attached.

[0036] With this configuration, the screw element can be easily attached because the pressing force of the pressing element is released after the screw element is attached to fix the pressure plate.

[0037] In the manufacturing method according to the above aspect, an external device that detects the pressing force of the pressing member may be used to detect the compression load applied to the cell stack when the pressing plate is fixed.

[0038] With this configuration, the structure of the fuel cell can be simplified because the fuel cell does not need to be provided with a detection part that detects the compression load on the fuel cell.

[0039] It should be noted that the present invention can be implemented in various forms. For example, the present invention can be implemented in the form of a fuel cell manufacturing apparatus, a vehicle equipped with a fuel cell, a method for attaching a screw member used to compress a cell stack, and a storage medium storing a control program that causes a system to perform these methods. Short description of the illustrations

[0040] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which like reference numerals designate like elements, and in which: Fig. 1 is an explanatory diagram used to explain the general configuration of a fuel cell of a first embodiment of the present invention; Fig. 2A and Fig. 2B are explanatory diagrams used to explain the general configuration of a case body according to the first embodiment; Fig. 3 is an explanatory diagram used to explain the general configuration of a unit cell according to the first embodiment; Fig. 4 is an explanatory diagram used to explain the positions of screw holes, push holes, and shaft holes of the housing body according to the first embodiment; Fig. 5 is an explanatory diagram used to explain the flow of a manufacturing method of a fuel cell according to the first embodiment; Fig. 6 is an explanatory diagram illustrating the manner in which the case body according to the first embodiment is placed on a manufacturing apparatus; Fig. 7 is an explanatory diagram illustrating the manner in which the unit cells according to the first embodiment are accommodated in a case body; Fig. 8 is an explanatory diagram illustrating the manner in which a plate member according to the first embodiment is attached to a front wall; Fig. 9A and Fig. 9B are exemplary illustrations used to explain the manner in which plunger members according to the first embodiment are mounted to a pre-assembly; Fig. 10A to Fig. 10C are exemplary diagrams used to explain the manner in which the compression load on the cell stack is adjusted according to the first embodiment; Fig. 11A and Fig. 11B are exemplary diagrams used to explain the manner in which a cover member according to the first embodiment is attached to the pre-assembly; Fig. 12 is an explanatory diagram used to explain the positions of push holes of a case body of a second embodiment of the present invention; Fig. 13 is an explanatory diagram used to explain the positions of push holes of a case body of a third embodiment of the present invention; Fig. 14 is an explanatory diagram used to explain the position of a push hole of a case body of a first modification of the above embodiments of the present invention; Fig. 15A to Fig. 15C are explanatory diagrams used to explain the position of a push hole of a case body of a second modification of the above embodiments of the present invention; and Fig. 16A and Fig. 16B are explanatory diagrams used to explain a fixing portion of a fuel cell of a third modification of the above embodiments of the present invention. Detailed description of embodiments

[0041] Fig. 1 is an explanatory diagram used to explain the general configuration of a fuel cell of a first embodiment. Fig. 1 illustrates a cross-sectional configuration of a fuel cell 10. The fuel cell 10 is a solid polymer fuel cell to which hydrogen and oxygen are supplied to generate electric power. The fuel cell 10 is mounted on a mobile body, such as a vehicle, and is used as a power source of the mobile body. The fuel cell 10 can be used as a stationary power supply. The fuel cell 10 includes a cell stack 100, a pair of terminal plates 203a and 203b, a pair of insulation plates 202a and 202b, a stack manifold 201, a pressure plate 200, a casing 300, and a plurality of load adjustment screws 500.

[0042] A plurality of unit cells 105 are stacked in the cell stack 100. The shape and configuration of the unit cell 105 will be described later in connection with Fig. 3. In the following description, the direction along the stacking direction of the cell stack 100 is referred to as the "x-direction," the direction perpendicular to the x-direction and extending along the longitudinal direction of the unit cells 105 is referred to as the "y-direction," and the direction perpendicular to the x-direction and the y-direction is referred to as the "z-direction." The terminal plates 203a and 203b as electrode plates are arranged on both sides of the cell stack 100, and the insulation plates 202a and 202b are arranged on both sides of the terminal plates 203a and 203b. The stack manifold 201 is arranged outside the insulation plate 202b to form flow paths for reaction gases (fuel gas, oxidizing gas, etc.) and a cooling medium between the exterior of the case 300 and the cell stack 100.The pressure plate 200, which is used to compress the cell stack 100, is arranged between the insulation plate 202a and the housing 300.

[0043] The housing 300 includes a housing body 305, a plate member 410, a cover member 420, and piston or plug members 430, all of which are made of a metal such as steel. The cell stack 100 is held under pressure or compressed in the stacking direction (x-direction) within the housing 300.

[0044] Fig. 2A and Fig. 2B are exemplary illustrations used to explain the general configuration of the housing body. Fig. 2A is a perspective view of the Fig. 1 shown housing body 305. The housing body is in Fig. 2A rotated in the vertical direction (z-direction). Fig. 2B is a perspective view showing the rear side (right side in Fig. 1) of the housing body 305. The housing body 305 has a substantially rectangular, box-shaped exterior configuration and includes a front wall 310, a rear wall 320, a top wall 330, a bottom wall 340, a right side wall 350, and a left side wall 360. The inner surfaces of the housing body 305 are coated with an insulating material (not shown) (such as a resin).

[0045] The front wall 310 is substantially perpendicular to the top wall 330, the bottom wall 340, the right side wall 350, and the left side wall 360. The front wall 310 includes edges 310f extending in a flange-like manner toward the top wall 330 and the bottom wall 340, and has a front opening 311 at the center thereof. The rear wall 320 is formed at a position opposite the front wall 310 and is substantially perpendicular to the top wall 330, the bottom wall 340, the right side wall 350, and the left side wall 360.

[0046] The rear wall 320 has screw holes 321, push holes 322 and piston holes 323. The screw holes 321 are screw holes (through holes) through which load adjustment screws 500 ( Fig. 1) with a threaded groove, and have a threaded groove which can be engaged with the threaded groove of each load adjusting screw 500 on the inner surface thereof. The pressing holes 322 are through holes through which pressing elements 120, which will be described later (refer to Fig. 10A to Fig. 10C), and in this embodiment have a circular outer configuration with a larger opening area than the screw openings 321. The piston openings 323 are through holes through which the piston elements 430 ( Fig. 1). The positions and number of screw holes 321, push holes 322 and piston holes 323 are described later in connection with Fig. 4 described in detail.

[0047] The upper wall 330 and the lower wall 340 are formed at opposite positions and are substantially perpendicular to the right side wall 350 and the left side wall 360. The lower wall 340 has a bottom opening 341 occupying almost the entire central portion thereof. The right side wall 350 and the left side wall 360 are formed at opposite positions and are connected at their peripheries to the peripheries of the front wall 310, the rear wall 320, the upper wall 330, and the lower wall 340. In this embodiment, the front wall 310 and the rear wall 320 are formed such that their normal direction extends along the x-direction, and the upper wall 330, the lower wall 340, the right side wall 350, and the left side wall 360 are formed parallel to the x-direction.A monitoring circuit 550, which monitors the cell voltage of the cell stack 100, is arranged in the housing body 305 along the right side wall 350.

[0048] As in Fig. 1, the plate member 410 having a substantially rectangular shape is attached to the front wall 310 by bolts 411, and the front opening 311 is closed by the plate member 410. Auxiliary components 450 are attached to the plate member 410. Examples of the auxiliary components 450 include conduits 452 and 454 through which reagent gases from external sources are supplied into the manifold, and a pump 453 used to supply a fuel gas (hydrogen). The cover member 420 having a substantially rectangular shape is attached to the bottom wall 340 by bolts 421, and the bottom opening 341 is closed by the cover member 420.

[0049] The piston elements 430 are rod-shaped elements, which are made of a metal, for example, and extend in the x-direction through the housing 300. Each piston element 430 has one end which is fixed to the plate element 410 by a nut 431, and another end which extends through a corresponding piston opening 323 and is fixed to the rear wall 320.

[0050] The load adjustment screws 500 are rod-shaped elements made of, for example, a metal and have a threaded groove. Each load adjustment screw 500 has a proximal end that is firmly screwed into a corresponding screw hole 321 of the rear wall 320 and a distal end that contacts the pressure plate 200. The length or distance from the rear wall 320 to the position where a load adjustment screw 500 contacts the pressure plate 200 can be adjusted by rotating the load adjustment screw 500.

[0051] The pressure plate 200 has the same flat, plate-like external configuration as the unit cells 105 and is arranged between the rear wall 320 of the casing body 305 and the cell stack 100. The pressure plate 200 preferably has a sufficiently greater thickness than the terminal plates 203a and 203b and the insulation plates 202a and 202b and can transmit the external compressive force evenly to the entire surface of the cell stack 100. The load adjustment screws 500 press the pressure plate 200 in the direction from the cell stack 100 toward the rear wall 320, but prevent it from moving. The pressure plate 200, the stack manifold 201, and the plate member 410 can be used as components (such as end plates) of a fuel cell stack including the cell stack 100.

[0052] The cell stack 100 is subjected to a prescribed load between the pressure plate 200 and the plate member 410 in the housing 300. In other words, the cell stack 100 of this embodiment is held in compression in the x-direction in the housing 300.

[0053] Fig. 3 is an exemplary diagram used to explain the general configuration of a unit cell. A unit cell 105 includes a seal-integrated membrane electrode assembly 150 and a pair of separators 160 and 180 (hereinafter referred to as "first separator 160" and "second separator 180," respectively) arranged to sandwich the seal-integrated membrane electrode assembly 150 from both sides. The seal-integrated membrane electrode assembly 150 includes a membrane electrode assembly 151 and a seal 158 formed along the peripheries of the membrane electrode assembly 151.The membrane electrode assembly 151 includes a solid polymer electrolyte film 152, an anode 153 and a cathode 154 arranged on both sides of the solid polymer electrolyte film 152, and a pair of gas diffusion layers 157 arranged outside the anode 153 and the cathode 154.

[0054] The solid polymer electrolyte film 152 is formed of a fluorine-based resin material or a hydrocarbon-based resin material and has good proton conductivity in a wet state. Both the anode 153 and the cathode 154 contain carbon particles on which a catalyst material (such as platinum) that promotes an electrochemical reaction is deposited (catalyst-deposited support), and a polymer electrolyte that has proton conductivity (such as a fluorine-based resin). The gas diffusion layers 157 are formed of a gas-permeable conductive material such as carbon paper. The seal 158 is formed by injection molding a synthetic resin or the like around the peripheries of the membrane electrode assembly 151.The first separator 160 and the second separator 180 have a plate-like outer configuration and are formed of a gas-impermeable conductive material such as high-density carbon prepared by compressing carbon to impart gas-impermeability thereto, a calcined carbon, or a metal material such as stainless steel.

[0055] The gasket-integrated membrane electrode assembly 150 and the separators 160 and 180 have through-holes at their peripheries, so that manifolds M1 to M6 through which reaction gases (fuel gas and oxidizing gas) and a cooling medium (such as water) flow in the stacking direction (x-direction) can be formed when the unit cells 105 are stacked. Specifically, an oxidizing gas (cathode supply gas) supplied from an external source flows through the manifold M1, and a gas that has permeated the membrane electrode assembly 151 and contains the oxidizing gas (cathode exhaust gas) flows through the manifold M2. A fuel gas (anode feed gas) supplied from an external source flows through the manifold M3, and a gas that has permeated the membrane electrode assembly 151 and contains the fuel gas (anode exhaust gas) flows through the manifold M4.A cooling medium supplied from an external source flows through the manifolds M5 and the cooling medium used for cooling flows through the manifolds M6.

[0056] One of the two main surfaces of the first separator 160, which faces the membrane electrode assembly 151, has flow path grooves (not shown) into which the fuel gas (anode feed gas) flows from the manifold M3. The other main surface of the first separator 160 has flow path grooves 161 into which the cooling medium flows from the manifolds M5. One of the two main surfaces of the second separator 180, which faces the membrane electrode assembly 151, has flow path grooves 181 into which the oxidizing gas (cathode feed gas) flows from the manifold M1. The other main surface of the second separator 180 has flow path grooves (not shown) into which the cooling medium flows from the manifolds M5.

[0057] The gasket-integrated membrane electrode assembly 150 and the separators 160 and 180 have a flat, rectangular, plate-like configuration with recesses 155, 165, and 185 at their corners, respectively. Of the peripheries of the gasket-integrated membrane electrode assembly 150 and the separators 160 and 180 extending in their longitudinal direction (y-direction), the peripheries opposite the bottom wall 340 when housed in the housing 300 have recesses 156, 166, and 186 near the center thereof, respectively.

[0058] Fig. 4 is an explanatory diagram used to explain the positions of the screw holes 321, the push holes 322, and the piston holes 323 of the housing body. Fig. 4 shows the rear wall 320 of the fuel cell 10 from the x-direction. In Fig. 4, the positions of the cell stack 100 and the monitoring circuit 550 are indicated by dashed lines. Since the cell stack 100 and the pressure plate 200 have essentially the same shape from the x-direction, the dashed lines in Fig. 4 also shows the position of the pressure plate 200.

[0059] The rear wall 320 of the case body 305 has eight screw holes 321, two push holes 322, and three piston holes 323. The eight screw holes 321 are formed at positions opposite to the peripheries of the cell stack 100 when viewed in the x-direction. This prevents the peripheries of the cell stack 100 from being bent by a reaction force from the cell stack 100 being held under pressure in the stacking direction (x-direction), since the load-adjusting screws 500 press the peripheries of the cell stack 100 when the load-adjusting screws 500 are inserted into the screw holes 321. In addition, the screw holes 321 are arranged to surround the push holes 322.This allows the distances from the screw holes 321 to the surface of the pressure plate 200 to be substantially equal, even if portions of the surface of the pressure plate 200 are bent around the positions where the pressure plate 200 is pressed by the pressing members 120 when the pressure plate 200 is pressed by the pressing members 120 through the pressing holes 322. Consequently, the reaction force from the cell stack 100 in a compressed state is equally distributed to the load-adjusting screws 500 after the load-adjusting screws 500 are attached to the screw holes 321.

[0060] The two pressing holes 322 are arranged on both sides of the center of gravity GC of the cell stack 100, as viewed in the x-direction. In other words, the two pressing holes 322 are arranged such that the center of gravity GC of the cell stack 100 is located between the two pressing holes 322, as viewed in the x-direction. This allows the resultant force of the compressive forces applied to the pressure plate 200 to act at a point close to the center of gravity GC of the cell stack 100 when the pressing elements 121 press the pressure plate through the pressing holes 322. This prevents the generation of a moment due to the difference between the point of application of the resultant force and the center of gravity GC, and allows the cell stack 100 to be compressed straight in the stacking direction (x-direction).

[0061] In this embodiment, the two push holes 322 are formed at the same distance D from the center of gravity GC of the cell stack 100. This allows the resultant force of the compressive forces applied to the pressure plate 200 to act at a point closer to the center of gravity GC of the cell stack 100. In this embodiment, the push holes 322 have a circular configuration, which allows the insertion of the circular, columnar push elements 120 therethrough. Therefore, while the distance D is shown as the distance from the center of gravity GC of the cell stack 100 to the edges of the push holes 322 closest to the center of gravity GC of the cell stack 100, the distance D can be defined as the distance from the center of gravity GC of the cell stack 100 to the centers of the push holes 322.

[0062] The two pressing holes 322 may be arranged at different distances from the center of gravity GC of the cell stack 100, as long as they are arranged on both sides of the center of gravity GC of the cell stack 100 when viewed in the x-direction. This is because when the pressure plate 200 is compressed by a plurality of pressing elements 120, the cell stack 100 can be compressed straight in the stacking direction, even if the point of application of the resultant force does not necessarily have to precisely coincide with the center of gravity GC of the cell stack 100. The pressing holes 322 may have a threaded groove on their inner surfaces.

[0063] The three piston openings 323 are aligned along the periphery of the rear wall 320, which is connected to the bottom wall 340. Two of the three piston openings 323 on both sides are formed at positions opposite the grooves defined by the recesses 155, 165, and 185 of the gasket-integrated membrane electrode assembly 150 and the separators 160 and 180, as viewed in the x-direction. The middle of the three piston openings 323 is formed at a position opposite the groove defined by the recesses 156, 166, and 186 of the gasket-integrated membrane electrode assembly 150 and the separators 160 and 180. As described above, the three piston openings 323 are not opposed to the cell stack 100, but are opposed to the plate member 410 mounted on the opposite side of the housing body 305 via the grooves described above.Since the three piston openings 323 are aligned along the periphery of the rear wall 320, which is connected to the bottom wall 340, the piston elements 430 extending between the piston openings 323 and the plate element 410 can absorb the reaction force from the cell stack 100 compressed in the stacking direction. This prevents the bottom wall 340 with the bottom opening 341 from being deformed.

[0064] Fig. 5 is an exemplary flowchart used to explain the flow of the manufacturing method of the fuel cell 10. In manufacturing the fuel cell 10, the casing body 305, to which the monitoring circuit 550 (refer to Fig. 2A) was applied to a manufacturing device 600 (reference to Fig. 6) or set up there (step S110).

[0065] Fig. 6 is an exemplary diagram used to illustrate the manner in which the casing body is placed on the manufacturing apparatus. The manufacturing apparatus 600, which is an apparatus used for manufacturing a fuel cell, includes a flat, plate-shaped table 610, a stationary guide 620, and a movable guide 630. The stationary guide 620 has an elongated outer configuration and is fixed to the table 610. The movable guide 630 has an elongated outer configuration similar to that of the stationary guide 620 and is horizontally movable with its surface flush with the surface of the stationary guide 620. The casing body 305 is placed on the table 610 of the manufacturing apparatus 600.At this time, the case body 305 is placed such that the stationary guide 620 and the movable guide 630 are arranged in the case body 305 above the bottom opening 341. After the case body 305 is mounted on the manufacturing apparatus 600, the unit cells 105 are placed in the case body 305 (step S120 in FIG. Fig. 5).

[0066] Fig. 7 is an explanatory diagram illustrating the manner in which the unit cells 105 are placed in the case body 305. First, a portion of the movable guide 630 in the case body 305 is pulled out of the case body 305 through the front opening 311 of the case body 305. The pressure plate 200, the insulation plate 202a, the terminal plate 203a, a plurality of unit cells 105 (the cell stack 100), the terminal plate 203b, the insulation plate 202b, and the stack manifold 201 are arranged in this order on top of the movable guide 630, which has been partially pulled out of the case body 305, and on top of the stationary guide 620. Thereafter, a pressing mechanism 460 is used to press the pressure plate 410 to which the auxiliary components 450 have been attached to compress the cell stack 100 in the stacking direction (x-direction).The cell stack 100 is compressed or arranged under pressure in the stacking direction (x-direction) in the case body 305. At this time, the plate member 410 is pressed and brought into contact with the front wall 310.

[0067] Fig. Fig. 8 is an exemplary diagram illustrating the manner in which the plate member 410 is fixed to the front wall 310. The plate member 410 is fixed in contact with the front wall 310 by the bolts 411 (step S130 in Fig. 5). Consequently, the cell stack 100 is held in the casing body 305 under a prescribed load in the stacking direction. The fuel cell assembly that has passed step S130, in which the plate member 410 is attached to the front wall 310, may hereinafter be referred to as "pre-assembly 11." After step S130, the pre-assembly 11 is removed from the manufacturing apparatus 600. Then, the piston members 430 are attached to the pre-assembly 11 (step S140).

[0068] Fig. 9A and Fig. 9B are exemplary illustrations illustrating the manner in which the piston or plug elements 430 are attached to the pre-assembly 11. As in Fig. 9A, the pre-assembly 11 is mounted on an installation jig 630. The installation jig 650 is a table on which the pre-assembly 11 is placed and which has a plurality of rollers (not shown) in its surface. The pre-assembly 11 is placed on the installation jig 650 such that the cell stack 100 touches the top of the installation jig 650. Thereafter, the piston elements 430 are inserted through the piston openings 323 of the pre-assembly 11. After the piston elements 430 are inserted from the rear wall 320 to the plate member 410, both ends of respective piston elements 430 are fastened to the rear wall 320 and the plate member 410 by nuts 431, as shown in Fig. 9B. After the piston elements 430 are attached to the pre-assembly 11, the compression load in the stacking direction (x-direction) is adjusted on the cell stack 100 (step S150).

[0069] Fig. 10A to Fig. 10C are exemplary illustrations used to explain the manner in which the compression load on the cell stack 100 is adjusted. As in Fig. As shown in FIG. 10A, the rod-shaped pressing members 120 are inserted through the pressing holes 322 to press the pressing plate 200. The cell stack 100 is compressed by the pressing force of the pressing plate 200 in the stacking direction (x-direction). In other words, the compression load on the cell stack 100 in the stacking direction can be adjusted by adjusting the pressing force applied to the pressing plate 200 by the pressing members 120. In this embodiment, the pressing members 120 are included in a pressurizing unit 700 and can receive power from a driving part 710 of the pressurizing unit 700 to apply a predetermined load to the pressing plate 200. The pressurizing unit 700 includes a load measuring component 720 which can detect the load applied to the pressure plate 200 by the pressing elements 120.In other words, the pressurizing unit 700 can detect the compression load on the cell stack 100 in the stacking direction (x-direction). Therefore, the fuel cell itself does not need to have a detection component that detects the compression load on the cell stack 100, resulting in a reduction in the weight and manufacturing cost of the fuel cell.

[0070] When the compression load on the cell stack 100 in the stacking direction (x-direction) reaches a predetermined value, the load adjustment screws 500 are tightened as shown in Fig. 10B, while maintaining the compression load. The compression load may be, for example, approximately 36.5 kN. The load adjustment screws 500 are fastened by screwing the load adjustment screws 500 into the eight screw holes 321 of the rear wall 320. The tightening torque at this time may be, for example, 1 to 2.5 Nm. The load adjustment screws 500 are preferably screwed in with a tightening torque in the range of 5 Nm ± 30%, in other words, in the range of 3.5 to 6.5 Nm.

[0071] This is because the lower limit of the tightening torque is preferably at least 3 Nm to firmly seat the load adjusting screws 500 against the pressure plate 200. On the other hand, the upper limit of the tightening torque is preferably low enough so that the pressure plate 200 is hardly moved by the axial force from the load adjusting screws 500 generated by the tightening torque. When the load adjusting screws 500 are fastened with the compression load in the stacking direction on the cell stack 100 maintained at 36.5 kN by the pressurizing unit 700, the axial force per load adjusting screw 500 of the eight load adjusting screws 500 is preferably less than 4.56 (≈36.5 / 8) kN.In this embodiment, the load adjustment screws 500 are designed to apply an axial force of 1.6 kN or less when the tightening torque is 6.5 Nm or less to prevent the pressure plate 200 from being moved by the tightening torque.

[0072] After the eight load adjustment screws 500 are attached to the pre-assembly 11, the pressing elements 120 are removed from the pre-assembly 11 as shown in Fig. 10C. Since the load adjustment screws 500 substantially prevent the pressure plate 200 from moving after the pressing elements 120 are removed, the cell stack 100 is held in this position by the pressure plate 200 and the plate member 410, and the compression load in the stacking direction is maintained at a prescribed value (e.g., 36.5 kN). After the load adjustment screws 500 are fastened, a torque of 4 Nm ± 30% can be applied to the load adjustment screws 500 to check whether the load adjustment screws 500 are tight before the pressing elements 120 are removed. After removing the pressing elements 120, the cover member 420 is attached to the pre-assembly 11 (refer to Fig. 11A and Fig. 11B) (step S160).

[0073] Fig. 11A and Fig. 11B are exemplary illustrations illustrating the manner in which the cover member 420 is attached to the pre-assembly 11. As in Fig. 11A, the cover member 420 is attached to the bottom wall 340 by bolts 421 to close the bottom opening 341. This completes the manufacture of the fuel cell 10 as shown in Fig. 11B is shown.

[0074] The pressing holes 322 of this embodiment correspond to the "first holes" of the present invention. The screw holes 321 and the load-adjusting screws 500 of this embodiment correspond to the "fixing portion" of the present invention. The screw holes 321 of this embodiment correspond to the "internal thread portion" or the "second holes" of the present invention.

[0075] According to the above-described fuel cell 10 of this embodiment, the pressure plate 200 can be pressed from the outside of the casing body 305 through the pressing holes 322 in the stacking direction (x-direction), and the pressure plate 200 can be fixed in this position by attaching the load adjusting screws 500 to the screw hole 321, while pressing the pressure plate 200 in the stacking direction. Therefore, the fuel cell 10 in which the cell stack 100 is held compressed in the stacking direction in the casing body 305 can be easily manufactured.

[0076] A well-known method for manufacturing a fuel cell in which a cell stack is held compressed in the stacking direction in a casing body is to adjust the compression load on the cell stack by pressing a pressure plate with a screw member from outside the casing. In this case, however, chips may be generated from the screw hole because the screw member is screwed against the reaction force from the cell stack compressed in the stacking direction (x-direction). When the cell stack is pressed at three or more points, it is difficult to apply the resultant force of the compressive forces to a point near the center of gravity GC of the cell stack 100 because the cell stack cannot be sufficiently pressed at one or more points.Additionally, the fuel cell 10 requires a detection part that detects the compression load on the cell stack, since it is difficult to detect the compression load from outside the fuel cell 10. This may lead to an increase in manufacturing cost and weight. Furthermore, since the bolts used are selected during the manufacturing process, a loosening step for releasing the compression of the cell stack is required after the cell stack is preliminarily compressed and the dimensions of the cell stack are measured.

[0077] In contrast, according to the fuel cell 10 of this embodiment, since the load-adjusting screws 500 are installed after the cell stack 100 is compressed by the pressing members 120, the generation of chips from the screw holes 321 can be prevented. In addition, since the cell stack 100 is pressed at two points by the pressing members 120, the resultant force of the compressive forces can be applied to a point near the center of gravity GC of the cell stack 100. Furthermore, since the pressing plate 200 is pressed from outside the case body 305 through the pressing holes 322, the compression load on the cell stack 100 can be detected by an external device such as the pressurizing unit 700. Furthermore, since the load-adjusting screws 500 are installed after the cell stack 100 is compressed by the pressing members 120, a loosening step is unnecessary.This results in a shorter manufacturing process.

[0078] Another conventionally known method for adjusting the compression load on the cell stack is to insert a plurality of flat, plate-shaped washers between the casing and the cell stack. In this case, however, the weight of the fuel cell increases due to the weight of the washers, and it is not easy to finely adjust the compression load by changing the thickness of the washers. In contrast, according to the fuel cell 10 of this embodiment, since the load adjustment screws 500 are used to prevent the pressure plate 200 from moving, an increase in the weight of the fuel cell 10 is prevented. In addition, since an external pressurizing unit 700 is used to compress the cell stack 100, the compression load can be finely adjusted easily.

[0079] Fig. 12 is an explanatory diagram used to explain the positions of the push holes 322 of a case body 305b of a second embodiment of the present invention. Fig. 12 corresponds to Fig. 4 for the first embodiment. The fuel cell 10 of the first embodiment has a casing body 305 with two press holes 322, whereas a fuel cell 10b of the second embodiment has a casing body 305b with three press holes 322. The fuel cell 10b of the second embodiment is otherwise constructed in the same manner as the fuel cell 10 of the first embodiment, and therefore, a description thereof will be omitted.

[0080] The three pressing holes 322 of a rear wall 320b of the housing body 305b are arranged such that, from the x-direction perspective, they surround the center of gravity GC of the cell stack 100. In other words, the three pressing holes 322 are arranged such that, from the x-direction perspective, the center of gravity GC of the cell stack 100 is located in an area A surrounded by the three pressing holes 322. This allows the resultant force of the compressive forces applied to the pressure plate 200 to act at a point close to the center of gravity GC of the cell stack 100 when the pressure plate 200 is pressed through the pressing holes 322 with the aid of the pressing elements 120.

[0081] In this embodiment, the pressing holes 322 have a circular configuration, which allows insertion of the circular, columnar pressing elements 120 therethrough. Therefore, the region A is defined as a region surrounded by the lines connecting the centers of the pressing holes 322. The center of gravity of the region A coincides with the center of gravity GC of the cell stack 100 when viewed in the x-direction. This configuration allows the resultant force of the pressing forces applied to the pressing plate 200 to be applied at a point closer to the center of gravity GC of the cell stack 100. The region A can be defined as the smallest area of the areas formed by connecting the edges of the pressing holes 322.

[0082] According to the fuel cell 10b of the above-described embodiment, even if the casing body 305b has three pressing holes 322, the fuel cell 10b can be easily manufactured because the cell stack 100 can be compressed straight in the stacking direction (x-direction) using three pressing members 120. When the cell stack 100 is compressed using four pressing members 120, a situation may occur in which three of the pressing members 120 press the pressure plate 200, but the other pressing member 120 cannot sufficiently press the pressure plate 200, and the point at which the resultant force of the forces applied to the pressure plate 200 is applied may be shifted from the center of gravity GC of the cell stack 100 when viewed in the x-direction.Therefore, the number of pressing elements 120 is preferably three or four when a plurality of pressing elements 120 are used to press the pressure plate 200.

[0083] Fig. 13 is an explanatory diagram used to explain the position of the push hole 322 of a case body 305c in a third embodiment of the present invention. Fig. 13 corresponds to Fig. 4 for the first embodiment. A fuel cell 10c of the third embodiment has a casing body 305c with only one push hole 322. The fuel cell 10c of the third embodiment is otherwise constructed in the same manner as the fuel cell 10 of the first embodiment, and therefore, a description thereof will be omitted.

[0084] One pressing opening 322 of a rear wall 320c of the housing body 305c is located opposite the center of gravity GC of the cell stack 100 from the x-direction perspective. In other words, the pressing opening 322 is arranged such that the center of gravity GC of the cell stack 100 is located within the opening from the x-direction perspective. This allows the pressing force applied by the pressing plate 200 to act at a point close to the center of gravity GC of the cell stack 100 when a pressing element 120 presses the pressing plate 200 through the pressing opening 322.

[0085] According to the fuel cell 10c of the above-described embodiment, even if the casing body 305c has only one pressing hole 322, the fuel cell 10c can be easily manufactured because the cell stack 100 can be straightly compressed in the stacking direction (x-direction) by means of a pressing member 120.

[0086] It is recognized that this invention is not limited to the above embodiments and may be embodied in various ways without departing from the spirit thereof. For example, the following modifications may be made.

[0087] Fig. 14 is an exemplary diagram used to explain the position of the pressing hole 322 of a casing body 305d of a first modification of the present invention. While the pressing holes 322 in the first to third embodiments are described as having a circular configuration, the pressing holes 322 may have any shape besides circular as long as they are large enough to allow insertion of the pressing elements 120. For example, a fuel cell 10d may have a pressing hole 322d large enough to allow insertion of a plurality of pressing elements 120, as shown in Fig. 14. On the other hand, the push holes 322 may be smaller than the screw holes 321, as long as they are large enough to allow insertion of the push elements 120.

[0088] Fig. 15A to Fig. 15C are explanatory diagrams used to explain the position of a pressing hole 322e of a case body 305e of a second modification. While the pressing holes 322 in the first to third embodiments are described as being formed through the rear wall 320 of the case body 305, the pressing holes 322 may be formed by a member other than the rear wall 320 of the case body 305, as long as the pressing plate 200 can be pressed in the stacking direction (x-direction) by means of a pressing member or members 120 from outside the case body 305.

[0089] An example is with reference to Fig. 15A to Fig. 15C. First, a pressing element 121 is prepared, which, as shown in Fig. 15A, includes a flat portion 121f and a rod portion 121b. The rod portion 121b has one end connected to an end surface of the flat portion 121f and the other end connected to a rotation drive source (not shown). As shown in Fig. As shown in Figure 15B, a fuel cell pre-assembly 11e according to a second modification includes a casing body 305e including a top wall 330 having an elongated opening as a pressing hole 322e. The pressing member 121 is inserted through the pressing hole 322e such that the flat portion 121f is disposed in the casing body 305e. Then, the pressing member 121 is rotated around the rod portion 121b, as shown in Fig. 15C. This allows the flat portion 121f to press on a pressure plate 200e to compress the cell stack 100 in the stacking direction.

[0090] Fig. 16A and Fig. 16B are exemplary diagrams used to explain a fixing portion of a fuel cell of a third modification. While the screw holes 321 and the load adjusting screws 500 are used as fixing portions that prevent the pressure plate 200, which is pressed in a direction from the cell stack 100 toward the rear wall 320 (x-direction), from moving in the above embodiments, any means other than the screw holes 321 and the load adjusting screws 500 may be used as long as the pressure plate 200 can be prevented from moving. For example, a rod member 501 may be inserted between the pressure plate 200 and the rear wall 320 as the fixing portion, as shown in FIG. Fig. 16A is shown.

[0091] Alternatively, as in Fig. 16B, instead of the screw holes 321, which are through holes, blind screw holes 321g may be formed in the rear wall 320 at positions opposite to the pressure plate 200 to receive the load adjustment screws 500. Alternatively, instead of the screw holes 321, openings may be formed through the upper wall 330 or the lower wall 340, or the right side wall 350 or the left side wall 360, so that the pressure plate 200 can be fixed by fixing the pressing member 121 in this position, which is shown in Fig. 15A to Fig. 15C, for example, after it is rotated. The pressure plate 200 can be fixed by bonding the pressure plate 200 to the case body 305 with an adhesive after the cell stack 100 is compressed. In this case, the adhesive serves as the fixing portion.

[0092] While the screw holes 321 and the pressing holes 322 are described as being formed through the rear wall 320 of the fuel cell 10 in the above embodiments, the screw holes 321 and the pressing holes 322 may be formed through the plate member 410 disposed at the front of the fuel cell 10. Even in this case, the cell stack 100 can be compressed in the stacking direction from outside the case body 305 through the pressing holes 322, and the load adjustment screws 500 can be inserted through the screw holes 321, with the cell stack 100 compressed by the pressing members 120.

[0093] While the fuel cell 10 in the above embodiments is described as having the pressure plate 200 in addition to the cell stack 100, a member which forms a part of the cell stack 100 and which can receive a stress from the pressing members 120 in the stacking direction at one end of the cell stack 100, such as a separator, may also be used as a pressure plate.

[0094] While the casing body 305 is described as having one to three pressing holes 322 in the above embodiments, the fuel cell 10 may have four or more pressing holes 322 because the pressing members 120 can be inserted through all of the first to third pressing holes 322 to compress the cell stack 100 even if the casing body 305 has four or more pressing holes 322.

[0095] Although the portions of the casing body 305 are referred to as "front wall 310," "rear wall 320," "top wall 330," "bottom wall 340," "right side wall 350," and "left side wall 360" in the above embodiments, these names are for descriptive purposes only and have no relation to the orientation in which the fuel cell 10 is installed. Additionally, the casing body 305 may have a shape such that the interfaces between the front wall 310, the rear wall 320, the top wall 330, the bottom wall 340, the right side wall 350, and the left side wall 360 cannot be clearly defined, and the interfaces may be defined arbitrarily.

[0096] While the rear wall 320 of the housing body 305 is described as having three types of openings, namely, the screw openings 321, the push openings 322, and the piston openings 323, in the above embodiments, the rear wall 320 may have four or more types of openings. The housing body 305 may not have the piston openings 323.

[0097] While a solid polymer fuel cell is used as the fuel cell in this embodiment, various types of fuel cells such as phosphoric acid fuel cells, molten carbonate fuel cells, and solid oxide fuel cells may be used.

Claims

[1] Fuel cell, comprising: a cell stack (100) in which a plurality of unit cells are stacked; a housing (300) which accommodates the cell stack; and a pressure plate (200) arranged in the housing at a position between one end of the cell stack (100) in the stacking direction and the housing (300); wherein the housing has a first opening (322) through which a pressing element (120) pressing on the pressure plate from outside the housing in the stacking direction is brought into contact with the pressure plate, and a fixing portion (500) which fixes the pressure plate in this position with the cell stack compressed in the stacking direction, where the fuel cell characterized by is that the fixing portion (500) has an internally threaded portion provided in the housing such that it faces the pressure plate in the stacking direction, and a screw member (500) having a proximal end connected to the internally threaded portion and a distal end in contact with the pressure plate, and a position of the first opening (322) in the housing and a position of the fixing portion (500) in the housing differ from each other. [2] The fuel cell according to claim 1, wherein the first opening (322) is opposite to the pressure plate in the stacking direction. [3] Fuel cell, comprising: a cell stack (100) in which a plurality of unit cells are stacked; a housing (300) which accommodates the cell stack; and a pressure plate (200) arranged in the housing at a position between one end of the cell stack in the stacking direction and the housing; where the fuel cell characterized by is that the housing (100) comprises at least one first opening (322) configured such that a pressing element (120) is inserted through it to press on the pressure plate (200) from outside the housing (300) in the stacking direction, and the pressing element (120) is removed through the first opening (322), and at least one second opening (321) configured such that it is used to fix the pressure plate (200) in this position with the cell stack (100) compressed in the stacking direction, wherein the first opening (322) and the second opening (321) have different opening areas. [4] The fuel cell according to claim 3, wherein the number of the first openings (322) having a larger opening area than the second opening (321) is one to three. [5] The fuel cell according to claim 4, wherein the number of the first openings (322) is two or three, and the first openings (322) are positioned such that the center of gravity of the cell stack is located between the two first openings or in a region surrounded by the three first openings when viewed in the stacking direction. [6] The fuel cell according to claim 4, wherein the number of the first openings (322) is one and the first opening (322) is arranged at a position opposite to the center of gravity of the cell stack as viewed in the stacking direction. [7] The fuel cell according to any one of claims 4 to 6, wherein the first opening (322) is used to bring a pressing member, which is used to press the pressure plate from outside the casing in the stacking direction, into contact with the pressure plate. [8] The fuel cell according to any one of claims 3 to 7, wherein the second opening (321) having a smaller opening area than the first opening (322) has a threaded groove at an inner periphery of the second opening. [9] Method for producing a fuel cell, which characterized by is that it has the following: Preparing a cell stack (100) in which a plurality of unit cells are stacked and a housing (300) used to accommodate the cell stack, Arranging the cell stack (100) in the housing so that one end of the cell stack in the stacking direction is opposite the housing via a pressure plate (200), compressing the cell stack (100) in the housing in the stacking direction by pressing on the pressure plate from outside the housing by means of a pressing element (120), and Fixing the pressure plate (200) in this position with the cell stack compressed by the pressing element (120) by a fixing section (500), wherein the fixing section has an internally threaded section provided in the housing such that it is opposite to the pressure plate in the stacking direction, and a screw element (500) having a proximal end connected to the internally threaded section and a distal end in contact with the pressure plate, wherein the housing (300) has at least two types of openings through a side wall of the housing, the cell stack (100) is arranged in the housing such that one end of the cell stack in the stacking direction is opposite the side wall via the pressure plate (200), the cell stack is compressed by pressing on the pressure plate (200) in the stacking direction from outside the housing through a first opening (322) of the side wall using a pressing element (120), and the pressure plate (200) is fixed by attaching the screw element (500) between the pressure plate (200) and a second opening (321) of the side wall. [10] The manufacturing method according to claim 9, wherein the pressure plate (200) is fixed by attaching the screw member (500) when the compression load applied to the cell stack by pressing the pressing member (120) reaches a predetermined value, and the pressing force of the pressing member (120) is released after the screw member (500) is attached. [11] The manufacturing method according to claim 10, wherein an external device which detects the pressing force of the pressing member is used to detect the compression load applied to the cell stack when the pressure plate is fixed.

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