Fuel cell stack and method for assembling a fuel cell stack

Abstract

To assemble a fuel cell stack at low cost.SOLUTION: A fuel cell stack 100 includes a cell laminate 101 formed by alternately stacking a film electrode structure and a separator, end plates 6 disposed on both sides of the cell laminate 101 in a stacking direction, a case 103 surrounding the cell laminate 101, and a guide member 10 that is attached to a case inner wall and extends in the stacking direction. The separator includes an engagement part that is engaged with the guide member. The end plate 6 has a concave part 61 that supports one end part of the guide member 10 in a longitudinal direction. The guide member 10 has, at the other end part in the longitudinal direction, an extension support part that detachably supports an extension guide member extending in the stacking direction continuously from the guide member 10.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell stack formed by stacking a plurality of cells, and a method for assembling a fuel cell stack. [Background technology]

[0002] In recent years, technological developments have been made on fuel cells that contribute to energy efficiency in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy. As a conventional technology related to fuel cell stacks used in this type of fuel cell, a fuel cell stack is known in which a cylindrical positioning pin is erected from an end plate on one end side, and power generation cells having separators are stacked while being positioned by the positioning pin (see, for example, Patent Document 1). In the fuel cell stack described in Patent Document 1, a support part is welded to each edge of a plurality of separators, and the power generation cells are positioned by inserting a positioning pin into a through hole provided in the support part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 7174789 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the fuel cell stack described in Patent Document 1, it is necessary to weld support members to a plurality of separators, which increases costs. [Means for solving the problem]

[0005] A fuel cell stack according to one embodiment of the present invention includes a cell stack formed by alternately stacking separators and membrane electrode assemblies each including an electrolyte membrane and an electrode, a first end plate and a second end plate disposed on either side of the cell stack in the stacking direction, a housing surrounding the cell stack, and a guide member attached to an inner wall of the housing and extending in the stacking direction. The separator has an engagement portion that engages with the guide member, the first end plate has an end support portion that supports one end of the guide member in the longitudinal direction, and the guide member has an extension support portion at the other end in the longitudinal direction that detachably supports an extension guide member that is connected to the guide member and extends in the stacking direction.

[0006] Another aspect of the present invention is a method of assembling a fuel cell stack, which includes the steps of: introducing a guide member along an inner wall of a housing and engaging one end of the guide member with an end support portion provided on a first end plate arranged at an end of the housing; attaching an extended guide member to the other end of the guide member to form a guide member assembly, and alternately stacking a membrane electrode structure including an electrolyte membrane and an electrode and a separator while engaging an engaging portion provided on the separator with the guide member assembly; placing a second end plate while being guided by the guide member assembly; shortening the length from the first end plate to the second end plate to a predetermined length and fixing the second end plate to the housing; and pulling out the extended guide member protruding outward beyond the second end plate from the other end of the guide member. Effect of the Invention

[0007] According to the present invention, a fuel cell stack can be assembled at low cost. [Brief description of the drawings]

[0008] [Figure 1] 1 is an exploded perspective view showing a schematic overall configuration of a fuel cell stack according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a perspective view showing a schematic configuration of a main part of the fuel cell stack shown in FIG. [Diagram 3]3 is a perspective view showing a schematic configuration of an electrode assembly included in the fuel cell stack of FIG. 2. [Figure 4] FIG. 4 is a plan view showing the arrangement of separators in the case. [Diagram 5] Enlarged view of part V in Figure 4. [Figure 6] 2 is a perspective view showing a fitting state of guide members included in the fuel cell stack of FIG. 1. FIG. [Figure 7] FIG. 4 is a plan view showing the positional relationship of a guide member with respect to an engagement groove and a recess. [Figure 8] FIG. 13 is a perspective view showing a state in which an extension guide member is attached to an upper end portion of the guide member. [Figure 9A] 9 is a top view of the upper end surface of the guide member in FIG. 8. [Figure 9B] 9 is a bottom view of the lower end surface of the extension guide member of FIG. 8 . [Figure 10] 13A and 13B are diagrams showing, in table form, other examples of the upper end surface of the guide member and the lower end surface of the extension guide member. [Figure 11A] 5A to 5C are diagrams showing an example of a procedure for assembling a fuel cell stack according to an embodiment of the present invention. [Figure 11B] FIG. 11B is a diagram showing an example of a procedure following FIG. 11A. [Figure 11C] FIG. 11C is a diagram showing an example of a procedure following FIG. 11B. [Figure 11D] FIG. 11D shows an example of a procedure following FIG. 11C. [Figure 11E] FIG. 11B is a diagram showing an example of a procedure following FIG. 11D. [Figure 12] FIG. 11B is a diagram showing an example of a procedure following FIG. 11E. [Figure 13] 9 is a perspective view showing a modified example of the extension guide member of FIG. 8. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 13. A fuel cell stack according to an embodiment of the present invention constitutes a main element 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. FIG. 1 is an exploded perspective view showing the overall configuration of a fuel cell stack 100 according to an embodiment of the present invention, and shows the state of the fuel cell stack 100 in the middle of assembly. For convenience, the three axial directions perpendicular to each other as 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 according to these definitions. The up-down direction is the stacking direction of the fuel cell stack 100 when the fuel cell stack 100 is assembled, and corresponds to the direction of gravity. The assembled fuel cell stack 100 is, for example, laid on its side and mounted on a vehicle.

[0011] 1, the fuel cell stack 100 has a cell stack 101 formed by stacking a plurality of power generating cells 1 in the front-rear direction, a pair of end units 102 disposed at the upper and lower ends, respectively, of the cell stack 101, and a roughly box-shaped case 103 surrounding the cell stack 101, and has a roughly rectangular parallelepiped shape as a whole. In Fig. 1, the case 103 is not shown in detail, and only the outline of the case 103 is shown by a two-dot chain line.

[0012] The case 103 has four generally rectangular side walls facing the front, rear, right and left sides of the cell stack 101. These four side walls form the case 103 into a generally box-like shape with an open top and bottom. The top and bottom of the case 103 are covered with end units 102. The case 103 is made of a metal such as aluminum or iron. Between the cell stack 101 and the side walls of the case 103, a guide member 10 extending in the vertical direction is interposed.

[0013] FIG. 2 is a perspective view showing a schematic configuration of a main part of the fuel cell stack 100, corresponding to a state in which the fuel cell stack 100 is mounted on a vehicle. In FIG. 2, three mutually orthogonal axial directions are represented as the X1-X2 direction, the Y1-Y2 direction, and the Z1-Z2 direction. The stacking direction of the fuel cell stack 100 (the up-down direction in FIG. 1) corresponds to the X1-X2 direction. In FIG. 2, the case 103 and the guide member 10 are omitted. Therefore, the detailed configuration of the peripheral portion of the cell stack 101 is not shown.

[0014] The cell stack 101 is formed by stacking a plurality of power-generating cells 1. For convenience, a single power-generating cell 1 is shown in Fig. 2. The power-generating cell 1 has an electrode assembly 2 having an assembly including an electrolyte membrane and an electrode, and separators 3, 3 arranged on both sides of the electrode assembly 2 in the X1-X2 direction and sandwiching the electrode assembly 2. The electrode assemblies 2 and the separators 3 are arranged alternately in the X1-X2 direction.

[0015] The separator 3 has a pair of metal thin plates with a corrugated cross section, and is integrally formed by joining the outer peripheries of these thin plates. A conductive material with excellent corrosion resistance is used for the separator 3, and examples of such materials include titanium, titanium alloy, and stainless steel. The pair of thin plates are formed into an uneven shape by press molding or the like so as to form a cooling flow path inside the separator 3 through which a coolant flows, and the power generation surface of the power generation cell 1 is cooled by the flow of the coolant. For example, water can be used as the coolant. The surface of the separator 3 facing the electrode assembly 2 is formed unevenly so as to form a gas flow path between the surface of the electrode assembly 2 joint, i.e., the power generation surface.

[0016] The separator 3 on the X1 direction side of the electrode assembly 2 is, for example, an anode side separator (anode separator), and an anode flow path through which a fuel gas flows is formed between the anode separator 3 and the assembled electrode assembly 2. The separator 3 on the X2 direction side of the electrode assembly 2 is, for example, a cathode side separator (cathode separator), and a cathode flow path through which an oxidizer gas flows is formed between the cathode separator 3 and the assembled electrode assembly 2. For example, hydrogen gas can be used as the fuel gas, and for example, air can be used as the oxidizer gas. Sometimes, the fuel gas and the oxidizer gas are called reaction gases without being distinguished from each other.

[0017] Fig. 3 is a perspective view showing a schematic configuration of the electrode assembly 2. As shown in Fig. 3, the electrode assembly 2 has a substantially rectangular assembly 20 and a frame 21 that supports the assembly 20. The assembly 20 is a membrane electrode assembly (so-called MEA; Membrane Electrode Assembly), and has an electrolyte membrane, an anode electrode provided on the surface of the electrolyte membrane facing in the X1 direction, and a cathode electrode provided on the surface of the electrolyte membrane facing in the X2 direction.

[0018] The electrolyte membrane is, for example, a solid polymer electrolyte membrane, and a thin film of perfluorosulfonic acid containing water can be used. The electrolyte is not limited to a fluorine-based electrolyte, and a hydrocarbon-based electrolyte can also be used.

[0019] The anode electrode is an electrode catalyst layer formed on the surface of the electrolyte membrane in the X1 direction and serves as a reaction field for the electrode reaction. A gas diffusion layer that diffuses and supplies the reactant gas is provided on the surface of the electrode catalyst layer in the X1 direction. The cathode electrode is an electrode catalyst layer formed on the surface of the electrolyte membrane in the X2 direction and serves as a reaction field for the electrode reaction. A gas diffusion layer that diffuses and supplies the reactant gas is provided on the surface of the electrode catalyst layer in the X2 direction. The electrode catalyst layer includes a catalyst metal that promotes the electrochemical reaction between hydrogen contained in the fuel gas and oxygen contained in the oxidant gas, an electrolyte having proton conductivity, and carbon particles having electron conductivity. The gas diffusion layer is made of a conductive material having gas permeability, such as a carbon porous body.

[0020] At the anode electrode, the fuel gas (hydrogen) supplied via the anode flow path and gas diffusion layer is ionized by the action of a catalyst and passes through the electrolyte membrane to move to the cathode electrode. The electrons generated at this time pass through an external circuit and are extracted as electrical energy. At the cathode electrode, the oxidant gas (oxygen) supplied via the cathode flow path and gas diffusion layer reacts with the hydrogen ions guided from the anode electrode and the electrons that have moved from the anode electrode to produce water. The produced water provides an appropriate humidity to the electrolyte membrane, and excess water is discharged outside the electrode assembly 2.

[0021] The frame 21 is a thin plate having a substantially rectangular shape and is made of insulating resin, rubber, or the like. A substantially rectangular opening 21a is provided in the center of the frame 21. The joint body 20 is provided so as to cover the entire opening 21a, and the peripheral portion of the joint body 20 is supported by the frame 21. On the Y1 side of the opening 21a of the frame 21, three through holes 211 to 213 penetrating the frame 21 in the X1-X2 direction are opened side by side in the Z1-Z2 direction. On the Y2 side of the opening 21a, three through holes 214 to 216 penetrating the frame 21 in the X1-X2 direction are opened side by side in the Z1-Z2 direction.

[0022] 2, the separator 3 has through holes 311-316 that penetrate the separator 3 in the X1-X2 direction at positions corresponding to the through holes 211-216 of the frame 21. The through holes 311-316 are connected to the through holes 211-216 of the frame 21, respectively. A collection of these mutually communicating through holes 211-216 and 311-316 form flow paths PA1-PA6 (indicated by arrows for convenience) that penetrate the cell stack 101 and extend in the X1-X2 direction. The flow paths PA1-PA6 are sometimes called manifolds. The flow paths PA1-PA6 are connected to a manifold outside the fuel cell stack 100.

[0023] A flow path PA1 (solid arrow) extending in the X1 direction via the through holes 211, 311 is a fuel gas supply flow path. A flow path PA6 (solid arrow) extending in the X2 direction via the through holes 216, 316 is a fuel gas discharge flow path. The fuel gas supply flow path PA1 and the fuel gas discharge flow path PA6 communicate with an anode flow path facing the surface of the joined body 20 in the X1 direction, and the fuel gas flows in the Y1-Y2 direction through the fuel gas supply flow path PA1 and the fuel gas discharge flow path PA6 as shown by the solid arrow. The communication between the anode flow path and the other flow paths PA2 to PA5 is blocked via a seal portion not shown.

[0024] A flow path PA4 (dotted arrow) extending in the X1 direction through the through holes 214, 314 is an oxidant gas supply flow path. A flow path PA3 (dotted arrow) extending in the X2 direction through the through holes 213, 313 is an oxidant gas discharge flow path. The oxidant gas supply flow path PA4 and the oxidant gas discharge flow path PA3 communicate with a cathode flow path facing the surface of the joined body 20 in the X2 direction, and the oxidant gas flows in the Y1-Y2 direction through the oxidant gas supply flow path PA4 and the oxidant gas discharge flow path PA3 as shown by the dotted arrow. The communication between the cathode flow path and the other flow paths PA1, PA2, PA5, PA6 is blocked by a seal portion not shown.

[0025] A flow path PA5 (indicated by dashed-dotted arrow) extending in the X1 direction through the through holes 215, 315 is a cooling medium supply flow path. A flow path PA2 (indicated by dashed-dotted arrow) extending in the X2 direction through the through holes 212, 312 is a cooling medium discharge flow path. The cooling medium supply flow path PA5 and the cooling medium discharge flow path PA2 are connected to a cooling flow path inside the separator 3, and the cooling medium flows through the cooling flow path via the cooling medium supply flow path PA5 and the cooling medium discharge flow path PA2. The communication between the cooling flow path and the other flow paths PA1, PA3, PA4, PA6 is blocked via a seal portion (not shown).

[0026] As shown in FIG. 2, the end units 102 arranged on both sides of the stacking direction of the cell stack 101 each have a terminal plate 4, an insulating plate 5, and an end plate 6. The end unit 102 on the X1 direction side may be called a dry side end unit, and the end unit 102 on the X2 direction side may be called a wet side end unit. The pair of terminal plates 4, 4 are arranged on both sides of the cell stack 101. The pair of insulating plates 5, 5 are arranged on both sides of the terminal plate 4, 4. The pair of end plates 6, 6 are arranged on both sides of the insulating plate 5, 5.

[0027] The terminal plate 4 is a substantially rectangular metal plate member, and has a terminal portion for extracting the electric power generated by the electrochemical reaction in the cell stack 101. The insulating plate 5 is a substantially rectangular non-conductive resin or rubber plate member, and electrically insulates the terminal plate 4 from the end plate 6. The end plate 6 is a metal or high-strength resin plate member.

[0028] FIG. 1 shows a pair of end plates 6, 6 as an end unit 102, and the terminal plate 4 and the insulating plate 5 are omitted. The upper end plate 6 in FIG. 1 is a dry-side end plate, and the lower end plate 6 is a wet-side end plate. Both upper and lower ends of a case 103 are fixed to the pair of end plates 6, 6 with bolts, respectively. More specifically, with the lower end plate 6 and the case 103 fixed to each other via bolts, the upper end plate 6 is pressed down from above, and the upper end plate 6 and the case 103 are fixed to each other by bolts. As a result, the fuel cell stack 100 is held in a pressed state by the pair of upper and lower end plates 6, 6.

[0029] As shown in Fig. 2, the wet-side (X2 direction) end unit 102 has a plurality of through holes 102a-102f that penetrate the end unit 102 in the front-rear direction. The through holes 102a-102f include a through hole that penetrates the terminal plate 4, a through hole that penetrates the insulating plate 5, and a through hole that penetrates the end plate 6, but in Fig. 1, for convenience, these are collectively shown as through holes 102a-102f. The dry-side (X1 direction) end unit 102 has the through holes 102a-102f opened in the terminal plate 4 and the insulating plate 5, similar to the wet-side end unit. On the other hand, the through holes 102-102f are not opened in the end plate 6 of the dry-side end unit 102.

[0030] The through hole 102a communicates with the fuel gas supply channel PA1. The through hole 102b communicates with the coolant discharge channel PA2. The through hole 102c communicates with the oxidant gas discharge channel PA3. The through hole 102d communicates with the oxidant gas supply channel PA4. The through hole 102e communicates with the coolant supply channel PA5. The through hole 102f communicates with the fuel gas discharge channel PA6.

[0031] A fuel gas tank storing high-pressure fuel gas is connected to the through-hole 102a, and the fuel gas in the fuel gas tank is supplied to the fuel cell stack 100 through the through-hole 102a. The fuel gas that has passed through the fuel gas discharge flow path PA6 is discharged through the through-hole 102f. A compressor for supplying oxidant gas is connected to the through-hole 102d, and the oxidant gas compressed by the compressor is supplied to the fuel cell stack 100 through the through-hole 102d. The oxidant gas that has passed through the oxidant gas discharge flow path PA3 is discharged through the through-hole 102c. A pump for supplying a cooling medium is connected to the through-hole 102e, and the cooling medium is supplied to the fuel cell stack 100 through the through-hole 102e. The cooling medium that has passed through the cooling medium discharge flow path PA2 is discharged through 102b.

[0032] 2 and 3 are merely schematic views of the positions and shapes of the through holes 211-216, 311-316, and 102a-102f in order to explain the flow of the reaction gas and the cooling medium. Some of the through holes through which the reaction gas and the cooling medium flow are also shown in FIG. 1 and FIG. 4 described later, but these through holes are also merely schematic views.

[0033] The fuel cell stack 100 according to this embodiment is characterized by the positioning structure of the cell stack 101. This point will be described below. FIG. 4 is a plan view (a top view of the cell stack 101 in FIG. 1) showing the arrangement of the separators 3 in the case 103. As shown in FIG. 4, the case 103 has front, rear, left and right side walls 103a. Ends of the side walls 103a are joined to each other, and the case 103 is configured as a frame as a whole so as to form a substantially rectangular parallelepiped space inside. Hereinafter, the direction toward the center P in the front, rear, left and right directions of the case 103 will be referred to as the inside of the case, and the direction away from the center P will be referred to as the outside of the case.

[0034] The separator 3 has engagement portions 35 at its front, rear, left and right edge portions 3a. The engagement portions 35 are provided, for example, at the left-right middle portion or the front-rear middle portion of the edge portion 3a of the separator 3. In the left and right edge portions 3a of the separator 3 in FIG. 4, the engagement portions 35 are provided at positions shifted from the front-rear middle portion, taking into consideration the positions of the through holes provided at both left and right ends of the separator 3. The guide members 10 are engaged with the engagement portions 35, and the separator 3 is supported by the side wall 103a of the case 103 via the guide members 10. On the other hand, when assembling the fuel cell stack 100, a single electrode assembly 2 is previously joined to a single separator 3 by welding or bonding to form a set of unit cells, and a plurality of sets of unit cells are sequentially stacked in the case 103. Therefore, no engagement portion is provided at the edge portion of the frame 21 (FIG. 3) of the electrode assembly 2, and the outer edge portion of the frame 21 is located inside the case with respect to the engagement portions 35.

[0035] FIG. 5 is an enlarged view (enlarged view of part V) of FIG. 4, showing the configuration around the guide member 10. As shown in FIG. The four guide members 10 have the same peripheral configuration. The guide members 10 are formed by extrusion molding using resin as a constituent material. Therefore, the cross-sectional shape of the guide members 10 is uniform in the longitudinal direction (vertical direction). As shown in FIG. 5, the guide members 10 are engaged with engagement grooves 110 provided in the side walls 103a of the case 103. The engagement grooves 110 are provided at positions corresponding to the engagement portions 35 of the separator 3. Therefore, as shown in FIG. 4, the engagement grooves 110 are provided at the left-right intermediate portions of the front and rear side walls 103a, and at positions shifted a predetermined amount from the front-rear intermediate portions of the left and right side walls 103a toward the corner portions.

[0036] The engagement groove 110 is constituted by a recess 120 provided on the inner surface 103b of the side wall 103a, and extends over the entire vertical length of the side wall 103a. More specifically, the engagement groove 110 has a predetermined width (length in the left-right direction) and depth (length in the front-rear direction) over the entire length of the side wall 103a. The inner surface 103b of the side wall 103a is provided with a pair of protrusions 121, 121 that protrude inward in the groove width direction (inward in the left-right direction). The protrusions 121 protrude further inwardly of the case than the other inner surface 103b of the side wall 103a.

[0037] By providing the protrusion 121, the width of the entrance side (inside the case) of the engagement groove 110 becomes narrower than the width of the bottom side (outside the case). The entrance side of the engagement groove 110 may be called the groove entrance portion 111, and the bottom side may be called the groove bottom portion 112. The protrusion 121 is formed so that the depth (length in the front-rear direction) of the groove bottom portion 112 is deeper than the depth of the groove entrance portion 111. The groove bottom portion 112 and the groove entrance portion 111 may be the same depth.

[0038] The guide member 10 is mainly composed of three parts in a plan view along the depth direction of the engagement groove 110. That is, it is composed of a base portion 11, a wide portion 12, and an engagement protrusion 13. The base portion 11 is disposed at the groove entrance portion 111, and has a generally rectangular shape in a plan view. The base portion 11 is disposed with a predetermined gap from the tips of the pair of protrusions 121, 121 in the groove width direction (left and right direction).

[0039] The wide portion 12 is disposed on the groove bottom surface portion 112. The wide portion 12 is formed to be larger in the groove width direction than the base portion 11, and the length of the wide portion 12 in the groove width direction is longer than the length of the groove entrance portion 111. Therefore, by engaging the wide portion 12 with the engagement groove 110, movement of the guide member 10 in the groove depth direction (front-rear direction) is restricted. In addition, by arranging the protrusion portion 121 opposite the base portion 11, movement of the guide member 10 in the groove width direction is restricted.

[0040] The engaging protrusion 13 protrudes toward the inside (front) of the case from an end of the base portion 11. A pair of engaging protrusions 13, 13 protrude from the base portion 11 in the groove width direction, and a recess 14 is provided between the pair of engaging protrusions 13, 13. The engaging protrusion 13 is formed in a generally rectangular shape in a plan view.

[0041] The engaging portion 35 has a pair of engaging recesses 36, 36 having a generally rectangular shape in a plan view in the groove width direction corresponding to the engaging protrusions 13. Furthermore, the engaging portion 35 has a protrusion 37 between the pair of engaging recesses 36, 36 corresponding to the recesses 14. The length of the engaging recesses 36 in the groove width direction is approximately equal to the length of the engaging protrusion 13 in the groove width direction. When the separators 3 are stacked, the pair of engaging recesses 36, 36 are fitted into the pair of engaging protrusions 13, 13 from above, and the protrusion 37 is fitted into the recess 14. This allows the separators 3 to be stacked while being positioned relative to the case 103 via the guide member 10.

[0042] 1, a recess 61 is provided on the upper surface of the lower (wet side) end plate 6 in correspondence with the position of the guide member 10. The recess 61 is a bottomed recess of a predetermined depth, and is not a through hole. The recess 61 has an inner circumferential shape that corresponds to the contour of the outer circumferential surface of the guide member 10, and the lower end of the guide member 10 is fitted into the recess 61.

[0043] FIG. 6 is a perspective view showing a state where the guide member 10 is fitted into the recess 61 (part VI in FIG. 1). As shown in FIG. 6, the guide member 10 is fitted to a predetermined depth until its lower end surface abuts against the bottom surface of the recess 61. As shown in FIG. 1, the upper (dry side) end plate 6 is provided with a through hole 62 corresponding to the position and shape of the guide member 10, i.e., a through hole 62 having the same shape as the inner peripheral surface of the recess 61. The upper end of the guide member 10 can be inserted through the upper end plate 6 via the through hole 62. However, when the assembly of the fuel cell stack 100 is completed, the upper end of the guide member 10 fits into the through hole 62 without protruding from the upper surface of the end plate 6. This allows both upper and lower ends of the guide member 10 to be held in a state where they are positioned by the end plate 6.

[0044] As described above, the guide member 10 is engaged with the recess 120 of the side wall 103a of the case 103, and the lower end of the guide member 10 is fitted into the recess 61. Fig. 7 is a plan view showing the positional relationship of the guide member 10 with respect to the engagement groove 110 and the recess 61. As shown in Fig. 7, the recess 61 is formed in an arc shape such that a corner portion facing a corner portion 13a of the engagement protrusion 13 of the guide member 10 is spaced from the corner portion 13a. That is, the corner portion of the recess 61 is provided with an arc portion 61a.

[0045] As shown in FIG. 7, if the distance between the end face of the base portion 11 of the guide member 10 and the end face of the recessed portion 61 in the groove width direction (left-right direction) facing each other is W1, and the distance between the end face of the base portion 11 and the end face of the protruding portion 121 in the groove width direction facing each other is W2, the recessed portion 61, the guide member 10, and the protruding portion 121 are formed so that W1 is smaller than W2. As an example, W1 is 0.1 to 0.2 mm, and W2 is about three times the value of W1. This allows the guide member 10 to be positioned with respect to the end plate 6 with high accuracy. In addition, since W2>W1, the guide member 10 can be easily engaged with the engagement groove 110 without interfering with the protruding portion 121.

[0046] Furthermore, if the distance between the end face of the wide portion 12 of the guide member 10 and the end face of the recess 120 in the groove width direction, which face each other, is W3, W3 is greater than W2. If the distance between the end face of the wide portion 12 and the end face of the protrusion 121 in the groove depth direction, which face each other, is D1, D1 is the same value as or approximately the same value as W2. This allows the wide portion 12 to be easily fitted into the engagement groove 110 while the guide member 10 is positioned by the protrusion 121.

[0047] A gap W2 between the guide member 10 and the protruding portion 121 in the groove width direction and a gap D1 in the groove depth direction are both very small (for example, about 0.4 to 0.55 mm). This makes it possible to restrict the displacement of the guide member 10, and to prevent the cell stack 101 from colliding with the side wall 103a of the case 103 when an impact is applied to the vehicle. That is, when an impact is applied to the vehicle, the cell stack 101 moves relative to the case 103 while rotating within the case due to inertia force, for example, as shown by the two-dot chain line in FIG. 4. For this reason, there is a risk that a corner of the cell stack 101 will collide with the side wall 103a, which may result in damage to the cell stack 101.

[0048] In this regard, in this embodiment, the guide member 10 is engaged with the engagement groove 110 so that the protrusion 121 is gripped, and thus it is possible to suppress displacement of the guide member 10 when an impact is applied to the vehicle. As a result, it is possible to suppress relative movement of the cell stack 101, and it is possible to protect the cell stack 101. In particular, as shown in Fig. 4, four guide members 10 are attached to the inner surface of the case 103 so that the engagement protrusions 13 face in different directions, and the four sides around the cell stack 101 are supported via the guide members 10, so that it is possible to effectively suppress displacement and rotation of the cell stack 101 within the case.

[0049] In this embodiment, the edge of the separator 3 is provided with an engagement portion 35 for engaging with the guide member 10, but the engagement portion 35 is simply an uneven shape (engagement recess 36). Therefore, when the separator 3 is formed by pressing, the engagement portion 35 can be processed at the same time. This eliminates the need to separately weld positioning tabs or the like to the edge of the separator 3, and allows the fuel cell stack 100 to be constructed at low cost.

[0050] A method for assembling the fuel cell stack 100 configured as above will be described. The fuel cell stack is assembled by stacking a plurality of power generating cells 1 and then applying pressure to the stack from the upper end plate 6, but before pressure is applied, the height of the stack is greater than the length of the guide member 10. For this reason, it is necessary to configure the guide member 10 to be extendable. Taking this into consideration, in this embodiment, the guide member 10 is configured as follows so that an extension guide member can be detachably attached to the upper end of the guide member 10.

[0051] Fig. 8 is a perspective view showing a state in the middle of attaching the extension guide member 40 to the upper end of the guide member 10. As shown in Fig. 8, an extension support part 15 that supports the extension guide member 40 so that it can be inserted and removed is provided on the upper end surface 10a of the guide member 10. Fig. 9A is a view of the upper end surface 10a of the guide member 10 seen from above, and Fig. 9B is a view of the lower end surface 40a of the extension guide member 40 seen from below. For convenience, the front-rear direction and the left-right direction are defined in Fig. 9A and Fig. 9B in accordance with Fig. 5. Since Fig. 9B is a view seen from below, the left-right direction is opposite to that in Fig. 9A.

[0052] 9B, the contour of the extended guide member 40 is the same as the contour of the guide member 10. Therefore, like the guide member 10, the extended guide member 40 has a base portion 41, a wide portion 42, and an engaging protrusion 43. The extended guide member 40 is a jig for assembling the fuel cell stack 100, and can be made of metal.

[0053] As shown in the enlarged view of part A in Fig. 8 and Fig. 9A, the extension support portion 15 is configured with a bottomed recess 16 that is generally T-shaped in plan view and has a predetermined depth, and is provided on the upper end surface 10a of the guide member 10. The bottomed recess 16 has a horizontal recess 161 that extends in the left-right direction along the boundary between the base portion 11 and the wide portion 12, and a vertical recess 162 that extends rearward from a left-right intermediate portion of the horizontal recess 161, penetrating the wide portion 12. Both left-right end surfaces of the horizontal recess 161 are formed in a semicircular shape.

[0054] As shown in the enlarged view of part A in FIG. 8 and FIG. 9B, a pair of cylindrical left and right pins 410, 410 are protruded downward from the lower end surface 40a of the extension guide member 40. The length of the pin 410 is shorter than the depth of the bottomed recess 16. The diameter of the pin 410 is equal to the width (front-rear length) of the lateral recess 161. The pin 410 is provided at positions corresponding to both left and right ends of the lateral recess 161, and the pin 410 is fitted into the bottomed recess 16 along the semicircular curved surfaces at both left and right ends of the lateral recess 161. The extension guide member 40 is pushed in until its lower end surface 40a abuts against the upper end surface of the guide member 10. At this time, the outer peripheral surface showing the outline of the guide member 10 and the outer peripheral surface showing the outline of the extension guide member 40 are connected without any step. This allows the guide member 10 to be extended upward by the amount of the extension guide member 40.

[0055] When the extension guide member 40 is attached to the guide member 10 via the pin 410, the pin 410 is stored in the bottomed recess 16, as shown by the dotted line in Fig. 9A. This prevents the extension guide member 40 from moving or rotating with respect to the guide member 10 by the pair of pins 410, 410, and the relative position of the extension guide member 40 with respect to the guide member 10 can be maintained at a predetermined position. The extension guide member 40 can be attached to the guide member 10 by pushing the pin 410 downward while engaging it with the bottomed recess 16. Moreover, the extension guide member 40 can be separated from the guide member 10 simply by pulling it upward. This makes it easy to attach and detach the extension guide member 40, i.e., to insert and remove it.

[0056] The configuration of the extension support portion 15 is not limited to the above. Instead of providing the bottomed recess 16 of a predetermined depth on the upper end surface 10a of the guide member 10, for example, a substantially T-shaped notch having the same shape as the bottomed recess 16 in a plan view may be provided from the upper end surface 10a to the lower end surface of the guide member 10. This makes the cross-sectional shape of the guide member 10 the same over its entire length, so that the guide member 10 can be easily formed by extrusion molding. Instead of providing the bottomed recess 16, a pair of left and right through holes corresponding to the shapes of the pair of left and right pins 410, 410 may be provided from the upper end surface 10a to the lower end surface of the guide member 10.

[0057] FIG. 10 shows other examples (first to fourth modified examples) of the extension support portion 15, and shows the shapes of the upper end surface 10a of the guide member 10 and the lower end surface 40a of the extension guide member 40 in the form of a table. For convenience, in FIG. 10, the front, rear, left and right directions are defined as in the same manner as in FIG. 9A and FIG. 9B. As shown in FIG. 10, in the first modified example, a substantially semicircular cutout 163 is provided in the center in the left and right direction of the rear surface of the wide portion 12 of the guide member 10 and the front surface of the recess 14. In correspondence with these cutouts 163, a pair of front and rear pins 420, 420 protrude from the lower end surface 40a of the extension guide member 40, and the pins 420 are fitted into the cutouts 163.

[0058] In the second modified example, substantially rectangular cutouts 164 are provided on the inside in the left-right direction from both left and right end faces of the base portion 11 of the guide member 10. Corresponding to these cutouts 164, a pair of front and rear pins 430, 430 are protruded from the lower end face 40a of the extension guide member 40, and the pins 430 are fitted into the cutouts 164. The pins 430 do not protrude outward in the left-right direction from the lower end face 40a of the extension guide member 40.

[0059] In the third modified example, a substantially rectangular cutout 165 is provided in the left-right center of the rear surface of the wide portion 12 of the guide member 10 and the front surface of the recess 14. Corresponding to these cutouts 165, a pair of front and rear pins 440, 440 protrude from the lower end surface 40a of the extension guide member 40, and the pin 440 fits into the cutout 165. The pin 440 does not protrude outward in the front-rear direction from the lower end surface 40a of the extension guide member 40.

[0060] In the fourth modified example, no recess or notch is provided on the upper end surface 10a of the guide member 10. On the other hand, an outer circumferential guide portion 45 is provided on the lower end surface 40a of the extended guide member 40 so as to protrude downward and surround the wide portion 42. When the extended guide member 40 is attached, the outer circumferential guide portion 45 surrounds the wide portion 12 of the guide member 10 as shown by the dotted line. At this time, the wide portion 12 of the guide member 10 becomes the extended support portion 15. In the fourth modified example, the rear end surface of the extended guide member 40 protrudes rearward from the rear end surface of the guide member 10 by the amount of the outer circumferential guide portion 45. Therefore, the upper end portion of the side wall 103a is configured so that the side wall 103a and the outer circumferential guide portion 45 do not interfere with each other.

[0061] Next, a method of assembling the fuel cell stack 100 according to this embodiment will be described. Figures 11A to 11E are diagrams showing an example of an assembly procedure for the fuel cell stack 100. When assembling the fuel cell stack 100, the guide member 10 is manufactured in advance by extrusion molding, and a guide member 10 of a predetermined length is prepared (preparation step). Next, as shown in Figure 11A, the case 103 is fixed to the wet side end plate 6 using bolts (case attachment step).

[0062] Next, as shown in FIG. 11B, the guide member 10 is inserted from above the case 103 along the engagement groove 110 (FIG. 5) provided on the inner surface of the side wall 103a of the case 103. Then, the lower end of the guide member 10 is fitted into the recess 61 on the upper surface of the end plate 6 (guide insertion process). At this time, before or after fitting the guide member 10, the extension guide member 40 is attached to the upper end surface 10a of the guide member 10 via the extension support part 15 (extension guide attachment process). Specifically, the pin 410 protruding from the lower end surface 40a of the extension guide member 40 is fitted into the bottomed recess 16 of the upper end surface 10a of the guide member 10 (FIG. 8), and the extension guide member 40 is held on the extension of the guide member 10 with the upper end surface 10a and the lower end surface 40a in contact with each other.

[0063] Next, the wet-side insulating plate 5 and the terminal plate 4 are inserted into the case 103 along the extension guide member 40 and the guide member 10, and are stacked in order. Furthermore, as shown in FIG. 11C, a predetermined number of unit cells, each of which is a single electrode assembly 2 and a single separator 3 previously joined together, are inserted into the case 103 along the extension guide member 40 and the guide member 10, and are stacked in order (stacking process). This forms the cell stack 101. In this case, the unit cell descends while the engagement protrusion 43 of the extension guide member 40 and the engagement protrusion 13 of the guide member 10 engage with the engagement portion 35 (engagement recess 36) at the edge of the separator 3. Therefore, the cell stack 101 can be formed in a state in which the electrode assembly 2 and the separator 3 are accurately positioned based on the wet-side end plate 6 and the case 103.

[0064] Next, the dry-side terminal plate 4 and the insulating plate 5 are lowered along the extension guide member 40 and stacked in order, and then, as shown in FIG. 11D, the dry-side end plate 6 is lowered along the extension guide member 40. In this case, the end plate 6 is placed above the cell stack 101 (strictly speaking, the insulating plate 5) while the extension guide member 40 is inserted into the through-hole 62 of the end plate 6 (final stacking step). Thereafter, a pressure is applied from above the end plate 6 using a pressurizing machine (not shown), and while the height of the dry-side end plate 6 is kept at a predetermined height, the dry-side end plate 6 is fixed to the case 103 using bolts (fixing step). In this state, the extension guide member 40 protrudes upward from the dry-side end plate 6.

[0065] Next, as shown in Fig. 11E, the extension guide member 40 is pulled out from the guide member 10 via the through hole 62 (pulling out process). Finally, as shown in Fig. 12, the through hole 62 in the end plate 6 is covered with a cover 64 via a sealing material 63 to seal the through hole 62 (sealing process). The cover 64 is fastened to the end plate 6 using, for example, a bolt. This completes the assembly of the fuel cell stack 100.

[0066] According to the above assembly method, the extension guide member 40 can be attached to the guide member 10 by fitting the extension guide member 40 from above the guide member 10. Also, the extension guide member 40 can be removed from the guide member 10 by pulling the extension guide member 40 upward. Therefore, the extension guide member 40 can be attached and detached more easily than an extension member attached via a screw portion. That is, when the extension member is attached via a screw portion, the extension member needs to be rotated, but in this embodiment, no rotation is required when attaching the extension guide member 40, so the extension guide member 40 can be attached and detached immediately. Also, when the extension member can be attached via a screw portion, extra space is required to rotate the extension member, but in this embodiment, such space is not required, so the fuel cell stack 100 can be made smaller.

[0067] The extension guide member 40 does not need to have the same cross-sectional shape over its entire length. Fig. 13 is a perspective view showing a modified example of the extension guide member 40. In the example shown in Fig. 13, the extension guide member 40 is configured to taper upward. That is, the thickness of the engaging protrusion 43 in the groove width direction gradually becomes thinner upward. This allows the engaging portion 35 of the separator 3 to easily engage with the extension guide member 40 from above.

[0068] According to this embodiment, the following advantageous effects can be obtained. (1) A fuel cell stack 100 includes a cell stack 101 formed by alternately stacking separators 3 and assemblies 20 (membrane electrode structures) including an electrolyte membrane and electrodes, a case 103 surrounding the cell stack 101, and a guide member 10 attached to an inner surface 103b of a side wall 103a of the case 103, extending in the stacking direction of the cell stack 101, and protruding toward an edge 3a of the separator 3 (FIGS. 1, 2, and 4). The separator 3 has an engagement portion 35 that engages with an engagement protrusion 13 at the tip of the guide member 10 (FIG. 4). The inner surface 103b of the side wall 103a has a recess 120 and a protrusion 121 as a guide support portion that supports the guide member 10 (FIG. 5). More specifically, the inner surface 103b has a pair of protrusions 121, 121 that restrict movement of the guide member 10 in the groove depth direction and also restrict movement in the groove width direction (FIG. 5).

[0069] This restricts the displacement and rotation of the guide member 10 relative to the case 103, while firmly holding the guide member 10 from the inner surface 103b of the case 103. Therefore, for example, when an external impact is applied to a vehicle equipped with the fuel cell stack 100, displacement and rotation of the cell stack 101 within the case due to inertial force is suppressed, and damage to the cell stack 101 can be suppressed.

[0070] (2) The guide support portion has a recess 120 that forms an engagement groove 110 of a predetermined depth extending along the stacking direction up to the end face of the case 103 in the stacking direction, and a protrusion 121 that protrudes toward the inside in the width direction of the engagement groove 110 at the groove entrance portion 111 so that the width of the groove entrance portion 111, which is the entrance side of the engagement groove 110, is narrower than the width of a groove bottom portion 112, which is the bottom side of the engagement groove 110 (FIG. 5). The guide member 10 has a base portion 11 that is disposed at the groove entrance portion 111, and a wide portion 12 that is disposed at the groove bottom portion 112 and expands in the width direction from the base portion 11 (FIG. 5). As a result, the guide member 10 is engaged with the engagement groove 110 by being gripped by the pair of protrusions 121, so that the displacement and rotation of the guide member 10 can be effectively suppressed.

[0071] (3) Protrusion 121 is located on the inside of inner side surface 103b of case 103. This increases the distance from the corner of cell stack 101 to inner side surface 103b, thereby preventing the corner of cell stack 101 from colliding with inner side surface 103b of case 103 when an external impact is applied.

[0072] (4) The length W2 of the gap from the opposing end faces of the wide portions 12 to the end faces of the protrusions 121 in the groove depth direction and the length W1 of the gap from the opposing end faces of the base portions 11 to the end faces of the protrusions 121 in the groove width direction are shorter than the length W3 of the gap from the opposing end faces of the groove bottom portions 112 to the end faces of the wide portions 12 in the groove width direction (FIG. 7). This allows the guide member 10 (particularly the wide portions 12) to easily engage with the engagement groove 110.

[0073] (5) The fuel cell stack 100 further includes an end plate 6 having a recess 61 that supports one end (lower end) of the guide member 10 in the longitudinal direction (FIG. 1). The guide member 10 has a base portion 11 and a wide portion 12 over the entire longitudinal length. The recess 61 is configured as a bottomed recess into which the lower end of the guide member 10 can be fitted (FIG. 1). A length W1 of the gap from the opposing end faces of the base portions 11 to the end face of the recess 61 in the groove width direction is shorter than a length W2 of the gap from the opposing end faces of the base portions 11 to the end faces of the protruding portions 121 in the groove direction (FIG. 7). This allows the guide member 10 to be accurately positioned with respect to the end plate 6, and allows the guide member 10 to be easily inserted into the engagement groove 110 over the entire length without interfering with the protruding portions 121.

[0074] (6) The recess 61 of the end plate 6 is formed so that the corner on the opposite side in the groove depth direction of the wide portion 12, i.e., the portion facing the corner of the engaging protrusion 13, has a substantially arc shape (FIG. 7). This makes it easy to fit the guide member 10.

[0075] (7) From a different viewpoint from the above, a fuel cell stack 100 includes a cell stack 101 formed by alternately stacking assemblies 20 including an electrolyte membrane and an electrode and separators 3, a wet-side end plate 6 and a dry-side end plate 6 arranged on both sides of the cell stack 101 in the stacking direction, a case 103 surrounding the cell stack 101, and a guide member 10 attached to an inner surface 103b of a side wall 103a of the case 103 and extending in the stacking direction (FIGS. 1 and 2). The separator 3 has an engagement portion 35 that engages with the guide member 10 (FIG. 4). The wet-side end plate 6 has a recess 61 that supports one end (lower end) of the guide member 10 in the longitudinal direction (FIG. 1). The guide member 10 has an extension support portion 15 at the other end (upper end) in the longitudinal direction that supports an extension guide member 40 that is continuous with the guide member 10 and extends in the stacking direction so as to be insertable and detachable (FIG. 8).

[0076] This eliminates the need to weld positioning tabs or the like to the edges of the separators 3, making it possible to inexpensively construct the fuel cell stack 100. In other words, it is only necessary to provide the edge 3a of the separator 3 with the engagement portion 35 that engages with the guide member 10, so that when the separator 3 is formed by, for example, press working, the engagement portion 35 can be formed at the same time, thereby reducing costs.

[0077] (8) The guide member 10 is made of a resin material with a constant cross-sectional shape over the entire length in the longitudinal direction. This allows a long guide member 10 to be obtained by extrusion molding. This reduces the occurrence of warping and sink marks compared to injection molding, and allows the guide member 10 to be formed with high precision. Furthermore, when changing the number of stacked power generation cells 1 to increase or decrease the power generation capacity, it is necessary to change the length of the guide member 10; however, because the guide member 10 can be formed by extrusion molding, it is easy to change the length of the guide member 10.

[0078] (9) The recess 61 of the end plate 6 is configured as a bottomed recess into which one end of the guide member 10 can be fitted. If the recess 61 were configured as a through hole, a seal or the like would need to be provided separately around the recess 61 to prevent moisture from entering the case. However, by forming the recess 61 as a bottomed recess, there is no need to provide a seal, and the configuration can be simplified.

[0079] (10) The wet-side end plate 6 is provided with a plurality of through holes 102a-102f for supplying and discharging the reactive gas and the cooling medium to and from the cell stack 101 (FIG. 2). On the other hand, the dry-side end plate 6 is not provided with such through holes for supplying and discharging, but has a through hole 62 through which the extension guide member 40 is inserted, and the through hole 62 is sealed by a cover 64 (FIGS. 1 and 12). If the dry-side end plate 6 is provided with a recess into which the lower end of the guide member 10 is fitted, and the wet-side end plate 6 is provided with a through hole through which the extension guide member 40 is inserted, the number of through holes in the wet-side end plate 6 that need to be sealed increases, and the configuration of the wet-side end plate 6 becomes complicated. In contrast, the dry-side end plate 6 allows the through holes 62 that need to be sealed to be easily formed.

[0080] (11) From a different viewpoint from the above, a method of assembling the fuel cell stack 100 includes a step of introducing the guide member 10 along the inner surface 103b of the side wall 103a of the case 103 and fitting one end (lower end) of the guide member 10 into a recess 61 provided in an end plate 6 arranged at an end of the case 103 (guide insertion step), and a step of attaching the extension guide member 40 to the other end (upper end) of the guide member 10 to form an assembly of the guide member 10 and the extension guide member 40 (referred to as guide member assembly 10, 40). The process includes a step of stacking separators 3 and 3 alternately while engaging engaging portions 35 provided on separator 3 with guide member assemblies 10, 40 (stacking step), a step of placing end plate 6 while being guided by guide member assemblies 10, 40 (final stacking step), a step of shortening the length from the lower end plate 6 to the upper end plate 6 to a predetermined length and fixing end plate 6 to case 103 (fixing step), and a step of pulling out extended guide member 40 protruding outward beyond the upper end plate 6 from the upper end of guide member 10 (pulling step) (FIGS. 11A to 11E).

[0081] With this configuration, the extension guide member 40 can be attached to and detached from the upper end of the guide member 10 by inserting the extension guide member 40 from above or pulling it out upward. This makes it easy to attach and detach the extension guide member 40. That is, when attaching and detaching an extension member such as the extension guide member 40 via a screw portion, an operation of rotating the extension member is required, but in this embodiment, no rotation operation is required. Therefore, the extension guide member 40 can be attached and detached easily and quickly.

[0082] (12) In the final stacking step, the end plate 6 is placed by inserting the extension guide member 40 into the through hole 62 provided in the upper end plate 6 (FIG. 11D). The method for assembling the fuel cell stack 100 further includes a step of sealing the through hole 62 (sealing step) after pulling out the extension guide member 40 (FIG. 12). This makes it possible to prevent moisture and the like from entering from the outside through the through hole 62.

[0083] (13) The method for assembling the fuel cell stack 100 further includes a step of manufacturing the guide member 10 by extrusion molding (preparation step). This allows the long guide member 10 to be formed with high precision, and makes it easy to insert the guide member 10 along the engagement groove 110 on the inner surface 103b of the case 103.

[0084] In the above embodiment, the cell stack 101 is surrounded by the case 103, but the configuration of the housing is not limited to the above. In the above embodiment, the wet-side end plate 6 out of the wet-side end plate 6 (first end plate) and the dry-side end plate 6 (second end plate) arranged on both sides of the stacking direction of the cell stack 101 is provided with a recess 61 for supporting one end of the guide member 10, but the configuration of the end support part is not limited to this. In the above embodiment, the other end of the guide member 10 is provided with an extension support part 15 for supporting the extension guide member 40 in an insertable and detachable manner, but the configuration of the extension support part is not limited to the above. In the above embodiment, the wet-side end plate 6 is provided with supply and exhaust through holes 102a to 102f for supplying the reaction gas and the cooling medium to the cell stack 101 and discharging the reaction gas and the cooling medium from the cell stack 101, but the shape and position of the through holes are not limited to the above.

[0085] The above description is merely an example, and the present invention is not limited to the above-mentioned embodiment and modifications, as long as the features of the present invention are not impaired. The above-mentioned embodiment and one or more modifications can be arbitrarily combined, and modifications can be combined with each other.

[0086] 3 separator, 6 end plate, 10 guide member, 15 extension support portion, 35 engagement portion, 61 recess, 64 cover, 100 fuel cell stack, 101 cell laminate, 102a to 102f through holes, 103 case, 110 engagement groove, 120 recess, 121 protrusion

Claims

1. a cell stack formed by alternately stacking a membrane electrode assembly including an electrolyte membrane and an electrode and a separator; a first end plate and a second end plate respectively disposed on both sides of the cell stack in a stacking direction; A housing that surrounds the cell stack; a guide member attached to an inner wall of the housing and extending in the stacking direction, the separator has an engagement portion that engages with the guide member, the first end plate has an end support portion that supports one end of the guide member in a longitudinal direction, a fuel cell stack including a guide member having an extension support portion at the other longitudinal end portion thereof for removably supporting an extension guide member connected to the guide member and extending in the stacking direction;

2. 2. The fuel cell stack according to claim 1, The fuel cell stack according to claim 1, wherein the guide member is made of a resin material having a constant cross-sectional shape over its entire length in the longitudinal direction.

3. 3. The fuel cell stack according to claim 1, 2. A fuel cell stack according to claim 1, wherein the end support portion is formed as a bottomed recess into which one end of the guide member can be fitted.

4. 4. The fuel cell stack according to claim 3, a supply and exhaust through hole formed in the first end plate for supplying a reactant gas and a cooling medium to the cell stack and for exhausting the reactant gas and the cooling medium from the cell stack, while the supply and exhaust through hole is not formed in the second end plate.

5. a step of introducing a guide member along an inner wall of a housing and fitting one end of the guide member into an end support portion provided on a first end plate disposed at an end of the housing; a step of alternately stacking a membrane electrode assembly including an electrolyte membrane and an electrode and a separator while engaging an engaging portion of the separator with the guide member assembly in a state in which an extension guide member is attached to the other end of the guide member to form a guide member assembly; placing a second end plate while being guided by the guide member assembly; a step of shortening a length from the first end plate to the second end plate to a predetermined length and fixing the second end plate to the housing; and pulling out the extension guide member, which protrudes outward beyond the second end plate, from the other end of the guide member.

6. The method for assembling a fuel cell stack according to claim 5, In the step of placing the second end plate, the guide member assembly is inserted into a through hole provided in the second end plate, and the second end plate is placed; The method for assembling a fuel cell stack, further comprising the step of sealing the through hole after the extension guide member is pulled out.

7. 7. The method for assembling a fuel cell stack according to claim 5 or 6, The method for assembling a fuel cell stack, further comprising the step of manufacturing the guide member by extrusion molding.

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