Fuel battery stack and manufacturing method for the fuel battery stack

Abstract

To arrange a stacked cell in a stack case while suppressing a contact between the stacked cell and a buffer member.SOLUTION: A fuel battery stack 100 includes a stacked cell 1, a stack case 30, and an end unit 20. The fuel battery stack 100 further includes, between the stack case 30 and the stacked cell 1, a buffer member 40 for receiving a collision of the stacked cell 1, and the buffer member 40 is provided with a first step part 41 for positioning in a vertical direction with respect to a fastening hole 24 provided in an end unit at a tip end inserted into the stack case 30. The end unit 20 is provided with a second step part 25 that positions the buffer member 40 in a left-right direction at a position where the buffer member 40 abuts, a first step part 41 and a second step part 25 are fitted to each other, and the fastening hole 24 is fastened by the fastening member 50 to position the end unit 20 and the buffer member 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In a conventional fuel cell assembly process, a stack case is provided with positioning guides, and positioning holes are formed in the flat plate-like components that make up the fuel cell. The flat plate-like components are then stacked in order into the positioning holes to form cells. This process is then repeated for the required number of cells to form a fuel cell stack.

[0003] For example, the abstract of Patent Document 1 discloses that "a fuel cell stack assembling method includes a knock pin positioning step of positioning knock pins that position unit cells, a stacking step of stacking the unit cells, and a compression step of compressing the unit cells, wherein the knock pin includes a knock pin main body portion that is placed in a positioning hole of the unit cell after the compression step, and a first extension portion and a second extension portion that are detachable and provided on both ends of the knock pin main body portion, and wherein after the compression step, a first extension portion removing step and a second extension portion removing step are provided to remove the first extension portion and the second extension portion while the unit cell is in a compressed state." [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-196849 A Summary of the Invention [Problem to be solved by the invention]

[0005] Here, a unit cell generally comprises a membrane electrode assembly and a pair of separators that sandwich the membrane electrode assembly from both sides, the separators being made of metal such as steel, stainless steel, or aluminum plates.

[0006] For example, in a fuel cell stack, if the guide portions constituting the positioning guides are made of resin, and a metal separator is stacked on the resin guide portions, the guide portions will be scraped off by contact with the separator, resulting in the problem of resin powder being mixed into the fuel cell stack. For this reason, methods have been considered in which, for example, the guide portions are made of metal when stacking unit cells, and then, after the unit cells are stacked, the metal guide portions are replaced with resin guide portions.

[0007] However, if the guide part is made of metal, there is a risk that the current generated by the unit cell itself will leak to the outside via the stack case.Furthermore, in fuel cell stacks, it is sometimes not possible to ensure sufficient clearance between the guide part and the unit cell, which creates the problem that the resin guide part can be worn away by sliding when inserted into the unit cell.

[0008] The present invention has been made in consideration of the above circumstances, and aims to provide a fuel cell stack that allows stacked cells to be arranged in a stack case while suppressing contact between the stacked cells and buffer members, and a method for manufacturing a fuel cell stack. [Means for solving the problem]

[0009] That is, in order to solve the above-mentioned problems of the present invention, a fuel cell stack is provided which includes a stacked cell formed by stacking a plurality of power generation cells, a stack case in which the stacked cell is housed, and an end unit arranged at one end of the stack case in the stacking direction, and further includes a buffer member for receiving impacts from the stacked cell between the stack case and the stacked cell, and the buffer member is provided with a first step portion at the tip inserted into the stack case for positioning in the up-down direction with respect to a fastening hole provided in the end unit, and the end unit is provided with a second step portion at a position where the buffer member abuts for positioning the buffer member in the left-right direction, and the first step portion and the second step portion are fitted together and the fastening hole is fastened with a fastening member to position the end unit and the buffer member. [Effects of the Invention]

[0010] According to the present invention, stacked cells can be arranged in a stack case while preventing contact between the stacked cells and the buffer member. [Brief explanation of the drawings]

[0011] [Figure 1] 2 is an enlarged longitudinal cross-sectional view showing a portion of the fuel cell stack according to the embodiment. FIG. [Figure 2] FIG. 10 is a partially omitted perspective view showing a buffer member attached to an end unit. [Figure 3] FIG. 2 is a perspective view of the end unit with a portion thereof omitted. [Figure 4] 1 is a flowchart showing a method for manufacturing a fuel cell stack. [Figure 5] FIG. 10 is an explanatory diagram of an end plate mounting step (step S001). [Figure 6] FIG. 10 is an explanatory diagram of a pin placement step (step S003). [Figure 7] FIG. 10 is an explanatory diagram of a lamination step (step S005). [Figure 8] FIG. 10 is an explanatory diagram of a compression step (step S007). [Figure 9]FIG. 10 is an explanatory diagram of a pin removing step (step S009). [Figure 10] FIG. 10 is an explanatory diagram of a buffer member inserting step (step S011). [Figure 11] FIG. 10 is an explanatory diagram of the fastening step (step S013). [Figure 12] FIG. 10 is an explanatory diagram showing a modified example in which the current collecting member and the first insulating member are slightly smaller than the outer shape of the stacked cell. DETAILED DESCRIPTION OF THE INVENTION

[0012] The following describes in detail embodiments of the present invention. Note that the embodiments described below are examples for realizing the present invention, and should be appropriately modified or changed depending on the configuration of the device to which the present invention is applied and various conditions. The present invention is not limited to the following embodiments. In addition, in each drawing, the same components are given the same reference numerals, and their description will be omitted as appropriate.

[0013] <Present Embodiment> [Fuel cell stack configuration] Fig. 1 is a vertical cross-sectional view showing an enlarged portion of a fuel cell stack according to this embodiment, Fig. 2 is a perspective view showing a portion of an end unit to which a buffer member is attached, and Fig. 3 is a perspective view showing a portion of the end unit.

[0014] As shown in FIG. 1, the fuel cell stack 100 according to this embodiment is configured to include a stacked cell 1, an end unit 20, and a stack case 30.

[0015] The stacked cell 1 is formed by stacking a plurality (a predetermined number) of power generating cells 10 in the Z direction. The power generating cells 10 are, for example, solid polymer fuel cells having a rectangular shape that is horizontally (or vertically) elongated in the X direction. The power generating cells 10 are mainly configured with a membrane electrode assembly (not shown) and a pair of separators (not shown) arranged on both sides (both sides in the Z direction) of the membrane electrode assembly.

[0016] Like the power generation cell 10, the separator also has a rectangular shape that is longer horizontally (or longer vertically) in the X direction. The separator is made of, for example, a steel plate, a stainless steel plate, an aluminum plate, a plated steel plate, a metal plate whose metal surface has been subjected to a corrosion-resistant surface treatment, or a carbon member.

[0017] The fuel cell stack 100 includes a stacked cell 1 in which a plurality of such power generating cells 10 are stacked, and is mounted on, for example, a fuel cell vehicle.

[0018] 1, the stacked cells 1 are housed in a stack case 30. The end unit 20 is disposed at one end of the stack case 30 in the stacking direction (-Z direction).

[0019] The end unit 20 is configured to include a current collecting member 21, a first insulating member 22 (insulator), and an end plate 23. As shown in Fig. 1, the end unit 20 is configured by stacking the current collecting member 21, the first insulating member 22 (insulator), and the end plate 23 in this order from the stacked cell 1 side toward the -Z direction.

[0020] Similarly, the fuel cell stack 100 is configured by stacking a current collecting member 21, a first insulating member 22, and an end plate 23 in this order toward the Z direction at the other end of the stacked cell 1 in the stacking direction (+Z direction).

[0021] That is, the pair of end plates 23, 23 in the fuel cell stack 100 are located at both ends of the stacking direction (Z direction) of the stacked cells 1, sandwiching the stacked cells 1. Similarly, the pair of current collecting members 21, 21 and the pair of first insulating members 22 are also located at both ends of the stacking direction (Z direction) of the stacked cells 1, sandwiching the stacked cells 1.

[0022] The end plate 23 is made of metal and has a rectangular shape that is horizontally (or vertically) long in the X direction. The end plate 23 also has fastening holes 24.

[0023] 1, the fuel cell stack 100 is configured to include a buffer member 40 between the stack case 30 and the stacked cells 1 for receiving a shock from the stacked cells 1. The buffer member 40 is configured, for example, by a second insulating member such as an insulator.

[0024] 1 and 2, the buffer member 40 abuts against the stacked cells 1 in the Y direction to position it. The buffer member 40 is made of, for example, resin, and has an elastic member 42 attached to the surface that abuts against the stacked cells 1. The buffer member 40 also has a first step 41 at the tip that is inserted in the -Z direction. The first step 41 of the buffer member 40 positions it in the up-down direction relative to the fastening hole 24 provided in the end plate 23 of the end unit 20.

[0025] 1 to 3, the end unit 20 is provided with a second step 25 at a position where the buffer member 40 abuts. The second step 25 of the end unit 20 positions the buffer member 40 in the left-right direction. The second step 25 is formed in the current collecting member 21 and the first insulating member 22.

[0026] As shown in FIG. 1, when the buffer member 40 is inserted between the stack case 30 and the stacked cells 1 in the fuel cell stack 100, the first step portion 41 of the buffer member 40 fits into the second step portion 25 of the end unit 20, as shown in FIG. 2.

[0027] 1, the stack case 30 has through holes 31. Fastening members 50 are inserted into the stack case 30 from the through holes 31 toward the end plates 23. The fastening members 50 fasten the buffer members 40 to the fastening holes 24 of the end plates 23. In the fuel cell stack 100, the end units 20 and the buffer members 40 are positioned by fastening the fastening members 50 into the fastening holes 24 of the buffer members 40.

[0028] In this embodiment, a clearance 60 is provided between the stack case 30 and the buffer member 40. The clearance 60 can be adjusted by a fastening member 50.

[0029] [Fuel cell stack manufacturing method] Next, a manufacturing method for manufacturing the fuel cell stack 100 using the assembly device 200 will be outlined with reference to a flowchart. Methods for manufacturing the fuel cell stack 100 include a method of stacking the power generating cells 10 in the stack case 30, and a method of stacking the power generating cells 10 and then fixing the stacked cells 10 to the stack case 30. In this embodiment, an outline of the method of stacking the power generating cells 10 in the stack case 30 will be explained as an example.

[0030] Fig. 4 is a flowchart showing a manufacturing method of the fuel cell stack 100. As shown in Fig. 4, the manufacturing method of the fuel cell stack 100 includes an end plate mounting step (step S001), a pin arrangement step (step S003), a stacking step (step S005), a compression step (step S007), a pin removal step (step S009), a buffer member insertion step (step S011), and a fastening step (step S013).

[0031] This embodiment is particularly characterized by the buffer member inserting step S011 and the fastening step S013. Each step will be explained below.

[0032] In the end plate mounting step (step S001) of FIG. 4, first, the pair of end plates 23 (end plates 23a, 23b) are mounted on the base plate 201 and the movable plate 206.

[0033] 5 is an explanatory diagram of the end plate attachment process (step S001). As shown in Fig. 5, the assembly device 200 is placed on a surface plate 290. The assembly device 200 is mainly composed of a base plate 201, a plurality of frames 205, a movable plate 206, and a hydraulic cylinder 207.

[0034] The base plate 201 is formed in a generally rectangular shape with an outer shape larger than that of the fuel cell stack 100 when viewed in the Z direction. The base plate 201 has a step portion 202a that protrudes in the Z direction. A pin insertion hole 203 is formed in the step portion 202a. A movable plate 206 is arranged in the Z direction of the multiple frames 205.

[0035] The movable plate 206 is formed in a shape that is approximately plane-symmetrical to the base plate 201. When viewed in the Z direction, the movable plate 206 is formed in a substantially rectangular shape whose outer shape is larger than that of the fuel cell stack 100. Frame insertion holes 208 that penetrate in the Z direction are formed in the four corners of the movable plate 206. The movable plate 206 is slidable in the Z direction, which is the extension direction of each frame 205. The movable plate 206 also has a step portion 202b that protrudes in the -Z direction (inward). A pin insertion hole 204 is formed in the step portion 202b.

[0036] 4, in the end plate mounting step (step S001), end plate 23a is mounted to step portion 202a of base plate 201. End plate 23b is mounted to step portion 202b of movable plate 206. The mounting is performed by fastening with bolts (not shown), for example.

[0037] A positioning hole 231 is formed in the end plate 23a, and a positioning hole 232 is formed in the end plate 23b. A stack case 30 in which the power generation cells 10 are stacked is attached to the end plate 23a. The end plate 23a and the stack case 30 are fastened together with, for example, bolts (not shown). As a result, the end plate 23a forms the bottom of the stack case 30.

[0038] Therefore, the end plate mounting step (step S001) is completed when the end plate 23a to which the stack case 30 is attached is mounted on the base plate 201 and the end plate 23b is mounted on the movable plate 206. Note that the stack case 30 may be mounted, for example, by fastening the stack case 30 after the end plate 23a is mounted on the base plate 201.

[0039] Returning to FIG. 4, the explanation will continue. In the pin placement step (step S003) of FIG.

[0040] 6 is an explanatory diagram of the pin placement step (step S003). As shown in FIG. 6, the assembly device 200 attaches the first extension portion 211 to the knock pin main body 210 and inserts the first extension portion 211 into the pin insertion hole 203 of the stepped portion 202a. In addition, the second extension portion 212 is attached to the knock pin main body 210.

[0041] The knock pin 213 is made up of a knock pin main body 210, a first extension 211, and a second extension 212. When the first extension 211 is placed on the step portion 202a of the assembly device 200 and the knock pin 213 is formed by the knock pin main body 210, the first extension 211, and the second extension 212, the assembly device 200 ends the pin placement process (step S003).

[0042] Returning to FIG. 4, the explanation will continue. In the stacking step (step S005) of FIG. 4, the first insulating members 22a and 22b, the current collecting members 21a and 21b, and the components of the plurality of power generating cells 10 are stacked.

[0043] 7 is an explanatory diagram of the stacking step (step S005). As shown in Fig. 7, the assembly device 200 stacks the first insulating member 22a, the current collecting member 21a, the plurality of power generating cells 10, the current collecting member 21b, and the first insulating member 22b in this order on the end plate 23a in the stacking direction (+Z direction).

[0044] At this time, the assembly device 200 stacks the first insulating members 22a, 22b, the current collecting members 21a, 21b, and the plurality of power generating cells 10 by inserting knock pins 213 into positioning holes (equivalent to the positioning holes 231 of the end plates 23) of each of these members. Once the assembly device 200 has stacked the first insulating members 22a, 22b, the current collecting members 21a, 21b, and the plurality of power generating cells 10, the stacking process (step S005) is completed.

[0045] Returning to FIG. 4, the explanation will continue. In the compression step (step S007) of FIG. 4, the stacked first insulating members 22a and 22b, current collecting members 21a and 21b, and each member of the plurality of power generating cells 10 are compressed.

[0046] 8 is an explanatory diagram of the compression step (step S007). As shown in FIG. 8, the assembly device 200 operates the hydraulic cylinder 207 to move the movable plate 206 and the end plate 23b in the −Z direction.

[0047] At this time, the knock pin 213 is inserted through the positioning hole 232 of the end plate 23b and the pin insertion hole 204 of the movable plate 206. As a result, the position of the end plate 23b in the X and Y directions is determined with high precision.

[0048] The assembly device 200 also moves the movable plate 206 and the end plate 23b further in the -Z direction and applies a predetermined load to compress the stacked first insulating members 22a, 22b, the current collecting members 21a, 21b, and each component of the plurality of power generating cells 10. When the first insulating members 22a, 22b, the current collecting members 21a, 21b, and each component of the plurality of power generating cells 10 are compressed and the stacked cell 1 is formed from the plurality of power generating cells 10, the compression step (step S007) ends.

[0049] Returning to FIG. 4, the explanation will continue. In the pin removing step (step S009) of FIG. 4, the assembling apparatus 200 removes the knock pin 213 from the stacked cell 1.

[0050] 9 is an explanatory diagram of the pin removal step (step S009). As shown in Fig. 9, the assembly device 200 removes the knock pin 213 (knock pin main body 210, first extension 211, second extension 212) from each of the compressed end plates 23a, 23b, first insulating members 22a, 22b, current collecting members 21a, 21b, and stacked cell 1 (plurality of power generating cells 10).

[0051] In this case, the assembly device 200 operates the hydraulic cylinder 207 to slide the movable plate 206 in the Z direction. Then, the assembly device 200 removes the second extension portion 212, the knock pin main body portion 210, and the first extension portion 211, in that order, from the compressed end plates 23a, 23b, the first insulating members 22a, 22b, the current collecting members 21a, 21b, and each member of the stacked cell 1 (plurality of power generating cells 10).

[0052] The assembly device 200 may, for example, attach tie rods (not shown) to the compressed first insulating members 22a and 22b, the current collecting members 21a and 21b, and each of the stacked cells 1 (plurality of power generating cells 10), and remove the knock pin 213 (knock pin main body 210, first extension 211, second extension 212). After removing the knock pin 213, the assembly device 200 ends the pin removal step (step S009).

[0053] Returning to FIG. 4, the explanation will continue. In the buffer member inserting step (step S011) of FIG. 4, the buffer member 40 is inserted between the stack case 30 and the stacked cells 1.

[0054] 10 is an explanatory diagram of the buffer member inserting step (step S011). As shown in FIG. 10, the assembly device 200 inserts the buffer members 40, to which the fastening members 50 are attached, between the stack case 30 and the stacked cells 1.

[0055] At this time, because a clearance 60 is provided between the stack case 30 and the buffer members 40, the assembly device 200 inserts the buffer members 40 while moving them toward the stack case 30 so that the buffer members 40 do not come into contact with the stacked cells 1. Note that the fastening members 50 are attached to the buffer members 40 for temporary fastening. In this way, once the assembly device 200 has inserted the buffer members 40, the buffer member insertion process (step S011) is completed.

[0056] Returning to FIG. 4, the explanation will continue. In the fastening step (step S013) of FIG. 4, the first step portion 41 and the second step portion 25 are fitted together and fastened together by the fastening member 50.

[0057] 11 is an explanatory diagram of the fastening step (step S013). As shown in FIG. 11, the assembly device 200 fits the first step portion 41 of the buffer member 40 into the second step portion 25 of the end unit 20, and fastens them with the fastening member 50 in the fastening hole 24. In this case, the assembly device 200 positions the end unit 20 and the buffer member 40. As a result, the clearance 60 between the stack case 30 and the buffer member 40 is appropriately set, and the elastic member 42 of the buffer member 40 abuts against the stacked cell 1.

[0058] When the assembly device 200 has finished positioning the end unit 20 and the buffer member 40 (step S013), the assembly device 200 removes the fuel cell stack 100 in which the stacked cells 1 are attached to the stack case 30, and the flow chart of FIG. 4 ends.

[0059] As described above, the fuel cell stack 100 according to this embodiment includes a stacked cell 1 formed by stacking a plurality of power-generating cells 10, a stack case 30 that houses the stacked cell 1, and an end unit 20 arranged at one end of the stack case 30 in the stacking direction. The fuel cell stack 100 further includes a buffer member 40 for receiving a collision of the stacked cell 1 between the stack case 30 and the stacked cell 1. The buffer member 40 is provided with a first step portion 41 at the tip that is inserted into the stack case 30, which determines vertical positioning with respect to fastening holes 24 provided in the end unit. The end unit 20 is also provided with a second step portion 25 at a position where the buffer member 40 abuts, which determines horizontal positioning of the buffer member 40. The first step portion 41 and the second step portion 25 fit together, and the fastening holes 24 are fastened with fastening members 50, thereby determining the positioning of the end unit 20 and the buffer member 40.

[0060] With this configuration, the fuel cell stack 100 according to this embodiment can fit the first step portion 41 of the buffer member 40 into the second step portion 25 of the end unit 20. Furthermore, the fuel cell stack 100 can fasten the end unit 20 and the buffer member 40 together with the fastening member 50 inserted through the through-hole 31 of the stack case 30.

[0061] As a result, in the fuel cell stack 100 of this embodiment, the buffer member 40 can be attached from the outside of the stacked cell 1, and therefore the stacked cell 1 can be placed inside the stack case 30 without causing resin powder to get mixed into the inside of the fuel cell stack 100 by attaching the buffer member 40.

[0062] In addition, the end unit 20 is constructed by stacking a current collecting member 21, a first insulating member 22, and an end plate 23 in this order from the stacked cell 1 side, the buffer member 40 is constructed of a second insulating member, and the second step portion 25 may be formed in the current collecting member 21 and the first insulating member 22.

[0063] According to this configuration, in the fuel cell stack 100 of this embodiment, the current collecting member 21, the first insulating member 22, and the end plate 23 are stacked in this order from the stacked cell 1 side, thereby forming both side end portions in the Z direction of the stacked cell 1. Furthermore, in the fuel cell stack 100, the first step portion 41 of the buffer member 40 can be fastened to the second step portion 25 formed in the current collecting member 21 and the first insulating member 22, so that the buffer member 40 and the end unit 20 can be firmly joined together.

[0064] In the fuel cell stack 100 according to this embodiment, the buffer member 40 may be made of resin, and an elastic member 42 may be attached to the surface that comes into contact with the stacked cells 1.

[0065] According to this configuration, the fuel cell stack 100 according to this embodiment can prevent displacement of the stacked cells 1 by bringing the buffer members 40 into contact with the stacked cells 1, even if a sudden load change occurs, such as a collision with the stack case 30. This allows the fuel cell stack 100 according to this embodiment to be resistant to impacts.

[0066] Furthermore, in the fuel cell stack 100 according to this embodiment, a clearance 60 is provided between the stack case 30 and the buffer member 40 , and the clearance 60 may be adjustable by the fastening member 50 .

[0067] With this configuration, the fuel cell stack 100 according to this embodiment can adjust the clearance 60 using the fastening members 50. As a result, the fuel cell stack 100 according to this embodiment can prevent fuel gas from leaking from the power generation cells 10 due to an impact by setting a margin against external impact, thereby ensuring the functionality and safety of the stacked cells 1.

[0068] Furthermore, the manufacturing method for the fuel cell stack 100 is a manufacturing method for a fuel cell stack 100 including the stacked cells 1, the stack case 30, and the end unit 20, and may further include a buffer member 40. The buffer member 40 is provided with a first step portion 41, and the end unit 20 is provided with a second step portion 25. As a result, the manufacturing method for the fuel cell stack 100 can perform a buffer member inserting step (step S011) and a fastening step (step S013).

[0069] Furthermore, in the method for manufacturing the fuel cell stack 100, in the fastening step (step S013), the buffer member 40 and the stacked cell 1 may be brought into contact with each other by fastening the fastening member 50, and the clearance 60 may be adjusted.

[0070] [Variations] Furthermore, the end unit 20 of the fuel cell stack 100 according to this embodiment is provided with a second step portion 25 at the position where the buffer member 40 abuts, which positions the buffer member 40 in the left-right direction, but this is not limited to this.

[0071] 1 and 11 showing this embodiment, the second step portion 25 is formed in the current collecting member 21 and the first insulating member 22. Here, the current collecting member 21 and the first insulating member 22 may be located at the same position as the second step portion 25 in the X direction and the Y direction of the buffer member 40.

[0072] 12 is an explanatory diagram showing a modified example in which the current collecting member and the first insulating member are made slightly smaller than the outer shape of the stacked cell. As shown in FIG. 11, in this modified example of the present embodiment, the current collecting member 21 and the first insulating member 22 can be positioned at the same position as the second step portion 25 along the entire periphery.

[0073] As a result, the current collecting members 21 and the first insulating members 22 of the end unit 20 can be made slightly smaller than the outer dimensions of the stacked cells 1, thereby making it possible to reduce the size and weight of the fuel cell stack 100. [Explanation of symbols]

[0074] 1. Stacked cell 10 Power generation cells 20 End Unit 21 Current collecting member 22 First insulating member 23 End plate 24 Fastening hole 25 Second step 30 Stack Case 31 Through hole 40 Cushioning material 41 First step 42 Elastic member 50 Fastening members 100 fuel cell stack

Claims

1. A fuel cell stack including a stacked cell formed by stacking a plurality of power generation cells, a stack case that houses the stacked cell, and an end unit that is disposed at one end of the stack case in a stacking direction, a buffer member for receiving a collision of the stacked cells is further provided between the stack case and the stacked cells, The buffer member includes: a first step portion for vertically positioning the end unit with a fastening hole provided in the end unit is provided at the tip end inserted into the stack case, The end unit includes: a second step portion for positioning the buffer member in the left-right direction is provided at a position where the buffer member abuts; The first step portion and the second step portion are fitted together, and the fastening holes are fastened with fastening members, thereby positioning the end unit and the buffer member. A fuel cell stack characterized by:

2. The end unit is a current collecting member, a first insulating member, and an end plate are stacked in this order from the stacked cell side; The buffer member is a second insulating member; The second step portion is formed on the current collecting member and the first insulating member, 2. The fuel cell stack according to claim 1.

3. The buffer member is made of resin, An elastic member is attached to the surface that contacts the stacked cells.

3. The fuel cell stack according to claim 1 or 2.

4. A clearance is provided between the stack case and the buffer member, The clearance is adjustable by the fastening member; 2. The fuel cell stack according to claim 1.

5. A method for manufacturing a fuel cell stack including a stacked cell formed by stacking a plurality of power generation cells, a stack case that houses the stacked cell, and an end unit that is disposed at one end of the stack case in a stacking direction, the method comprising: Further provided is a buffer member for receiving a collision of the stacked cells, The buffer member includes: a first step portion for vertically positioning the end unit with a fastening hole provided in the end unit is provided at the tip end inserted into the stack case, The end unit includes: a second step portion for positioning the buffer member in the left-right direction is provided at a position where the buffer member abuts; an insertion step of inserting the buffer member between the stack case and the stacked cells; a fastening step in which the first step portion and the second step portion are fitted together and fastened together by a fastening member in the fastening hole; A method for manufacturing a fuel cell stack, comprising:

6. A clearance is provided between the stack case and the buffer member, In the fastening step, the fastening member is fastened to bring the buffer member and the stacked cell into contact with each other and adjust the clearance. The method for manufacturing a fuel cell stack according to claim 5 .

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