Fuel cell stack

Abstract

To provide a fuel cell stack capable of satisfying mounting requests different per user.SOLUTION: A fuel cell stack 1 includes a cell laminate 3 in which a plurality of fuel battery cells are laminated, and a case 2 accommodating the cell laminate 3. The cell laminate 3 includes a positive electrode terminal 31, a negative electrode terminal 32, a positive electrode bus bar 33, and a negative electrode bus bar 34. One end of the positive electrode bus bar 33 and one end of the negative electrode bus bar 34 are connected to the positive electrode terminal 31 and the negative electrode terminal 32, respectively, and the other end of the positive electrode bus bar and the other end of the negative electrode bus bar are pulled out to the center position of a corner consisting of an upper cover 22 and a first side wall 23 so as to be adjacent each other. The case 2 has an upper surface opening 26 in the upper cover 22 at the center position of the corner, and a side opening 25 in the first side wall 23 at the center position of the corner. The positive electrode bus bar 33 and the negative electrode bus bar 34 can be connected to outside the case through the upper surface opening 26 and the side opening 25.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fuel cell stack. [Background technology]

[0002] Conventionally, one such technical field is described, for example, in Patent Document 1. The fuel cell stack described in Patent Document 1 includes a cell stack in which a plurality of fuel cell units are stacked, a first electrode terminal located at one end of the cell stack, a second electrode terminal located at the other end of the cell stack, a first connection terminal and a second connection terminal located at an end on the same side as the first electrode terminal, and a conductive member that provides electrical conductivity between the second electrode terminal and the second connection terminal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-277380 A Summary of the Invention [Problem to be solved by the invention]

[0004] When selling fuel cell stacks, different users have different installation requirements. For example, some users require the connection unit to be installed above the fuel cell stack, while others require it to be installed to the side of the fuel cell stack (e.g., on the left or right side). However, the above-mentioned fuel cell stack has a problem in that it cannot meet all of these installation requirements.

[0005] The present invention has been made to solve these technical problems, and has an object to provide a fuel cell stack that can meet the different mounting requirements of each user. [Means for solving the problem]

[0006] The fuel cell stack of the present invention is a fuel cell stack comprising a cell stack in which a plurality of fuel cell units are stacked, and a case that houses the cell stack, wherein the cell stack has a positive terminal, a negative terminal, a positive bus bar, and a negative bus bar, wherein one end of the positive bus bar and the negative bus bar are connected to the positive terminal or the negative terminal, and the other ends are extended to a central position of a corner formed by a top plate and a side wall of the case so as to be adjacent to each other, wherein the case has a first opening in the top plate at the central position of the corner and a second opening in the side wall at the central position of the corner, and wherein the positive bus bar and the negative bus bar are connectable to the outside of the case via the first opening and the second opening, respectively.

[0007] In the fuel cell stack according to the present invention, a first opening is provided in the top plate at the center of the corner, and a second opening is provided in the side wall at the center of the corner, so that it is possible to connect to the positive bus bar and the negative bus bar from outside the case through these openings. Therefore, a user's connection destination unit can be mounted from above and / or from the side of the fuel cell stack, so that different mounting requirements for each user can be met.

[0008] In the fuel cell stack according to the present invention, it is preferable to provide a restricting portion fixed to the other end of each of the positive bus bar and the negative bus bar and facing a corner of the cell stack to restrict displacement of the cell stack. In this way, the rigidity of the positive bus bar and the negative bus bar can be utilized to restrict displacement of the cell stack. Effect of the Invention

[0009] According to the present invention, it is possible to meet the mounting requirements that differ from user to user. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view showing a structure of a fuel cell stack according to an embodiment; [Diagram 2] FIG. 2 is a plan view showing the fuel cell stack with the upper cover removed. [Diagram 3] 1A is a plan view showing the positive bus bar, the negative bus bar, and the terminal block as viewed from the top opening, and FIG. 1B is a plan view showing the positive bus bar, the negative bus bar, and the terminal block as viewed from the side opening. [Figure 4] 1A is a schematic cross-sectional view showing a mounting pattern 1 of a destination unit, and FIG. 1B is a schematic cross-sectional view showing a mounting pattern 2 of a destination unit. [Diagram 5] 1A is a schematic cross-sectional view showing a mounting pattern 3 of a destination unit, and FIG. 1B is a schematic cross-sectional view showing a mounting pattern 4 of a destination unit. [Figure 6] 4 is an enlarged schematic cross-sectional view showing the positional relationship between a terminal block and a corner of a cell stack. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of a fuel cell stack according to the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated description will be omitted. In the following description, the stacking direction of the fuel cell units is referred to as the "stacking direction X", the gas flow direction in the fuel cell unit is referred to as the "left-right direction Y", and the direction perpendicular to the stacking direction X and the left-right direction Y is referred to as the "up-down direction Z".

[0012] Fig. 1 is a perspective view showing the structure of a fuel cell stack according to an embodiment, and Fig. 2 is a plan view showing the fuel cell stack with the upper cover removed. Fig. 3(a) is a plan view showing the positive bus bar, negative bus bar, and terminal block as viewed from the top opening, and Fig. 3(b) is a plan view showing the positive bus bar, negative bus bar, and terminal block as viewed from the side opening. As shown in Figs. 1 and 2, the fuel cell stack 1 of this embodiment includes a box-shaped case 2 and a cell stack 3 housed inside the case 2.

[0013] The cell laminate 3 is a cell stack formed by stacking a plurality of fuel cells in a certain direction, and constitutes a solid polymer electrolyte fuel cell. Although not shown, the fuel cell has a membrane / electrode assembly formed by sandwiching a polymer electrolyte membrane between an anode electrode and a cathode electrode, and a pair of separators that sandwich the membrane / electrode assembly from both sides. The fuel cell generates electricity by an oxidation-reduction reaction between oxygen gas in the air supplied through the separator on the cathode electrode side and hydrogen gas supplied through the separator on the anode electrode side.

[0014] The case 2 is formed in a rectangular box shape from a metal material such as aluminum. The case 2 has a case body 21 in the shape of a rectangular cylinder with a bottom, and an upper cover 22 that closes the opening of the case body 21. The upper cover 22 corresponds to a "top plate" in the claims, and is fixed to the case body 21 by bolting. The case body 21 is composed of a bottom plate portion, a pair of first side walls 23 that extend along the stacking direction X and face each other, and a pair of second side walls 24 that extend along the left-right direction Y and face each other.

[0015] As shown in FIG. 1, a pair of adjacent openings are provided on the top plate and the side wall of the case 2. More specifically, the upper cover 22 has a top opening (first opening) 26 for exposing the other ends of the positive bus bar 33 and the negative bus bar 34 and a part of the terminal block 4, which will be described later. The first side wall 23 has a side opening (second opening) 25 for exposing the other ends of the positive bus bar 33 and the negative bus bar 34 and a part of the terminal block 4. The top opening 26 is formed in the center of a corner formed by the first side wall 23 of the upper cover 22. Correspondingly, the side opening 25 is formed in the center of a corner formed by the first side wall 23 of the upper cover 22. The top opening 26 is closed by a top cover member 28, and the side opening 25 is closed by a side cover member 27.

[0016] The top opening 26 and the side opening 25 may be formed to have a common shape or different shapes. If they have a common shape, the processing work for these openings can be standardized, and the top cover member 28 and the side cover member 27 for closing the openings can be standardized, so that it is possible to reduce the cost of parts.

[0017] The cell stack 3 has a positive electrode terminal 31, a negative electrode terminal 32, a positive electrode bus bar 33, and a negative electrode bus bar 34. These terminals and bus bars are each formed into a plate shape from a metal material such as aluminum. The positive electrode terminal 31 and the negative electrode terminal 32 are arranged on both sides of the stacking direction X of the fuel cell so as to face each other. In other words, the positive electrode terminal 31 is arranged near one of the pair of opposing second side walls 24, and the negative electrode terminal 32 is arranged near the other of the pair of opposing second side walls 24.

[0018] One end of the positive bus bar 33 and the negative bus bar 34 is connected to the positive terminal 31 or the negative terminal 32, and the other ends are drawn out to the center of the corner formed by the upper cover 22 and the first side wall 23 of the case 2 so as to be adjacent to each other. A terminal block 4 is disposed near the center of the corner formed by the upper cover 22 and the first side wall 23. The other end of each of the positive bus bar 33 and the negative bus bar 34 is fixed to the terminal block 4.

[0019] Specifically, the positive bus bar 33 is bridged between the positive terminal 31 and the terminal block 4 so as to electrically connect the positive terminal 31 and the terminal block 4. As shown in FIG. 2 and FIG. 3, the positive bus bar 33 has a flat plate portion 331 arranged parallel to the upper cover 22 and having a curved shape, and an L-shaped portion 332 having a portion parallel to the upper cover 22 and a portion parallel to the first side wall 23. One end of the flat plate portion 331 is fixed to the positive terminal 31 by bolt fastening, and the other end is fixed to the L-shaped portion 332 and the terminal block 4 via a bolt 100. On the other hand, the L-shaped portion 332 has a portion parallel to the upper cover 22 fixed to the other end of the flat plate portion 331 and the terminal block 4 via the bolt 100, and a portion parallel to the first side wall 23 fixed to the terminal block 4 via a bolt 101.

[0020] The negative bus bar 34 is bridged between the negative terminal 32 and the terminal block 4 so as to electrically connect the negative terminal 32 and the terminal block 4. As shown in FIG. 2 and FIG. 3, the negative bus bar 34 has a flat plate portion 341 arranged parallel to the upper cover 22 and having a curved shape, and an L-shaped portion 342 having a portion parallel to the upper cover 22 and a portion parallel to the first side wall 23. One end of the flat plate portion 341 is fixed to the negative terminal 32 by bolt fastening, and the other end is fixed to the L-shaped portion 342 and the terminal block 4 via the bolt 102. On the other hand, the L-shaped portion 342 has a portion parallel to the upper cover 22 fixed to the other end of the flat plate portion 341 and the terminal block 4 via the bolt 102, and a portion parallel to the first side wall 23 fixed to the terminal block 4 via the bolt 103.

[0021] In addition, the positive bus bar 33 and the negative bus bar 34 do not necessarily have to be formed to have the flat portion 331, 341 and the L-shaped portion 332, 342. For example, the flat portion 331 and the L-shaped portion 332 may be integrally formed from a single plate member.

[0022] The terminal block 4 is made of a metal material such as aluminum, and is fixed to the case 2 in a state in which it is electrically insulated from the case 2.

[0023] In this embodiment, the positive electrode terminal 31 and the negative electrode terminal 32 arranged at both ends of the cell stack 3 in the stacking direction X are collected at the terminal block 4 arranged near the center of the corner formed by the upper cover 22 and the first side wall 23 by the positive electrode bus bar 33 and the negative electrode bus bar 34, so that it is possible to reduce the opening (i.e., the side opening 25 or the top opening 26) required for connection when assembling a connection destination unit on the user side to the fuel cell stack 1. Therefore, compared to a case where the bus bars are arranged at both ends of the stacking direction X of the cell stack 3, for example, the shape of the connection destination unit does not need to extend to both ends in the stacking direction X, so the connection destination unit can be made smaller.

[0024] Furthermore, since upper cover 22 has top opening 26 for exposing the other ends of positive bus bar 33 and negative bus bar 34, it becomes possible to connect to positive bus bar 33 and negative bus bar 34 from outside case 2 via top opening 26. This allows a connection destination unit on the user's side to be mounted above case 2 (in other words, above fuel cell stack 1).

[0025] Furthermore, since the first side wall 23 has a side opening 25 for exposing the other ends of the positive bus bar 33 and the negative bus bar 34, it becomes possible to connect to the positive bus bar 33 and the negative bus bar 34 from outside the case 2 via the side opening 25. This allows a user-side connection unit to be mounted on the side of the case 2 (in other words, on the side of the fuel cell stack 1).

[0026] In this way, since the user's destination unit can be mounted from above and / or the side of the case 2, it is possible to meet the mounting requirements that vary from user to user. As a result, it is possible to improve the robustness of mounting the destination unit.

[0027] Hereinafter, patterns for mounting destination units on the fuel cell stack 1 will be described with reference to Figs.

[0028] [Mounting pattern 1] 4(a) is a pattern in which a destination unit 5 is mounted on the side of the fuel cell stack 1. In this pattern, a connection bus bar 51 provided on the destination unit 5 is inserted from a side opening 25 of the case 2, and fixed to the positive bus bar 33 or the negative bus bar 34 via bolts 100, 102 with the connection bus bar 51 placed on the upper surface of the flat plate portions 331, 341 of the positive bus bar 33 or the negative bus bar 34. The connection bus bar 51 is made of a straight metal plate.

[0029] When mounting the connection destination unit 5 on the side of the fuel cell stack 1 in this manner, first, the side cover member 27 and the top cover member 28 of the fuel cell stack 1 are removed to expose the other ends of the positive bus bar 33 and the negative bus bar 34. Next, the connection destination unit 5 is assembled to the fuel cell stack 1 from the side of the case 2 such that the connection bus bar 51 is inserted into the inside of the case 2 from the side opening 25. Next, a fastening tool is inserted from the top opening 26 of the case 2, and the connection bus bar 51 is fastened to the flat plate portions 331, 341 of the positive bus bar 33 or the negative bus bar 34 with the bolts 100, 102. After fastening, the top opening 26 of the case 2 is closed with the top cover member 28.

[0030] In mounting pattern 1, the connection destination unit 5 is assembled to the fuel cell stack 1 from the side of the case 2, and the connection bus bar 51 is fastened to the positive bus bar 33 or the negative bus bar 34 of the fuel cell stack 1 with a fastening tool from above the case 2, making it easy to mount the connection destination unit 5. Also, since no service hole for inserting the fastening tool is required in the connection destination unit 5, costs can be reduced compared to when a service hole is provided in the connection destination unit 5.

[0031] [Mounting pattern 2] 4(b) is a pattern in which the destination unit 5 is mounted on the side of the fuel cell stack 1. In this pattern, the connection bus bar 52 provided on the destination unit 5 is inserted from the side opening 25 of the case 2 and fixed to the positive bus bar 33 or the negative bus bar 34 via the bolts 101, 103 in a state of contact with the L-shaped portions 332, 342 of the positive bus bar 33 or the negative bus bar 34. The connection bus bar 52 is made of a metal plate with an L-shaped cross section, having a portion 521 extending along the left-right direction Y and a portion 522 extending along the up-down direction Z. The portion 522 extending along the up-down direction Z has a size that allows it to be inserted through the side opening 25 of the case 2.

[0032] When mounting the destination unit 5 on the side of the fuel cell stack 1 in this manner, first, the side cover member 27 of the fuel cell stack 1 is removed to expose the other ends of the positive bus bar 33 and the negative bus bar 34. Next, the destination unit 5 is assembled to the fuel cell stack 1 from the side of the case 2 so that the connection bus bar 52 is inserted into the inside of the case 2 from the side opening 25. Next, a fastening tool is inserted into the service hole 53 formed in the destination unit 5, and the portion 522 of the connection bus bar 52 and the L-shaped portions 332, 342 of the positive bus bar 33 or the negative bus bar 34 are fastened with the bolts 101, 103.

[0033] In mounting pattern 2, the connection destination unit 5 is assembled to the fuel cell stack 1 from the side of the case 2, and the connection bus bar 52 is fastened to the positive bus bar 33 or the negative bus bar 34 from the side of the case 2 using the service hole 53 of the connection destination unit 5. This means that no work from above the case 2 is required. Therefore, other components 6 may be disposed above the top opening 26.

[0034] [Mounting pattern 3] 5(a) is a pattern in which a destination unit 5 is mounted above the fuel cell stack 1. In this pattern, a connection bus bar 54 provided on the destination unit 5 is inserted from an upper opening 26 of the case 2 and fixed to the positive bus bar 33 or the negative bus bar 34 via bolts 101, 103 in a state where it overlaps with the L-shaped portions 332, 342 of the positive bus bar 33 or the negative bus bar 34. The connection bus bar 54 is made of a straight metal plate.

[0035] When mounting the connection destination unit 5 above the fuel cell stack 1 in this manner, first, the side cover member 27 and the top cover member 28 of the fuel cell stack 1 are removed to expose the other ends of the positive bus bar 33 and the negative bus bar 34. Next, the connection destination unit 5 is assembled to the fuel cell stack 1 from above the case 2 such that the connection bus bar 54 is inserted into the inside of the case 2 from the top opening 26. Next, a fastening tool is inserted from the side opening 25 of the case 2, and the connection bus bar 54 is fastened to the L-shaped portions 332, 342 of the positive bus bar 33 or the negative bus bar 34 with the bolts 101, 103. After fastening, the side opening 25 of the case 2 is closed with the side cover member 27.

[0036] In mounting pattern 3, the connection destination unit 5 is assembled to the fuel cell stack 1 from above the case 2, and the connection bus bar 54 is fastened to the positive bus bar 33 or the negative bus bar 34 of the fuel cell stack 1 with a fastening tool from the side of the case 2, facilitating the work of mounting the connection destination unit 5. Also, since no service hole for inserting the fastening tool is required in the connection destination unit 5, costs can be reduced compared to when a service hole is provided in the connection destination unit 5.

[0037] [Mounting pattern 4] Mounting pattern 4 shown in FIG. 5(b) is a pattern in which a destination unit 5 is mounted above the fuel cell stack 1. In this pattern, a connection bus bar 55 provided on the destination unit 5 is inserted from the top opening 26 of the case 2 and fixed to the positive bus bar 33 or the negative bus bar 34 via bolts 100, 102 in a state of contact with the flat plate portions 331, 341 of the positive bus bar 33 or the negative bus bar 34. The connection bus bar 55 is made of a metal plate with an L-shaped cross section, having a portion 551 extending along the up-down direction Z and a portion 552 extending along the left-right direction Y. The portion 552 extending along the left-right direction Y has a size that allows it to be inserted through the top opening 26 of the case 2.

[0038] When mounting the connection destination unit 5 above the fuel cell stack 1 in this manner, first, the top lid member 28 of the fuel cell stack 1 is removed to expose the other ends of the positive bus bar 33 and the negative bus bar 34. Next, the connection destination unit 5 is assembled to the fuel cell stack 1 from above the case 2 so that the connection bus bar 55 is inserted into the inside of the case 2 from the top opening 26. Next, a fastening tool is inserted into the service hole 56 formed in the connection destination unit 5, and the portion 552 extending in the left-right direction Y of the connection bus bar 55 is fastened to the flat plate portion 331, 341 of the positive bus bar 33 or the negative bus bar 34 with the bolts 100, 102.

[0039] In mounting pattern 4, the connection destination unit 5 is assembled to the fuel cell stack 1 from above the case 2, and the connection bus bar 55 is fastened to the positive bus bar 33 or the negative bus bar 34 from above the case 2 using the service hole 56 of the connection destination unit 5, so that no work is required from the side of the case 2. Therefore, other components 6 may be disposed to the side of the side opening 25.

[0040] Furthermore, the terminal block 4 of this embodiment serves as a restricting portion that restricts the displacement of the cell stack 3. This will be described below with reference to FIG.

[0041] 6, the terminal block 4 has an L-shaped cross section so as to fit into a corner 35 of the adjacent cell stack 3. The terminal block 4 has a first portion 40 extending along the left-right direction Y and a second portion 41 extending along the up-down direction Z.

[0042] Here, the reason why the terminal block 4 is formed to have an L-shaped cross section will be described.

[0043] In case 2, both ends of the cell stack 3 in the stacking direction X are fixed to the case 2, but the portion between the ends is not fixed to the case 2 and is floating. Therefore, when an external force is applied to the fuel cell stack 1, the portion between the both ends of the cell stack 3 in the stacking direction X moves (i.e., is displaced). The central portion between the both ends of the cell stack 3 in the stacking direction X is displaced the most. Recently, in order to increase the output of the fuel cell stack, an increase in the number of stacked fuel cells has been considered. However, when the number of stacked fuel cells increases, the mass of the cell stack 3 increases, and the amount of displacement of the cell stack 3 when an external force is applied also increases. When the allowable amount of misalignment between adjacent fuel cells is exceeded, a seal failure occurs, leading to problems such as water leakage and hydrogen leakage.

[0044] In order to solve these problems, the inventors of the present application conducted extensive research and discovered that by arranging the terminal block 4 in a position on the case 2 corresponding to the central part of the stacking direction X of the cell stack 3 that is most displaced by external forces (more specifically, near the central position of the corner formed by the upper cover 22 and the first side wall 23), making the terminal block 4 L-shaped with portions corresponding to the top and side surfaces of the cell stack 3, and using the terminal block 4 to suppress (in other words, restrict) the displacement of the cell stack 3 in the left-right direction Y and the up-down direction Z, it is possible to restrict the amount of displacement of the cell stack 3 to below an allowable value.

[0045] 6, the terminal block 4 is disposed so that the inside of its L-shaped corner faces the corner 35 of the cell stack 3 so as to align with the corner 35 of the cell stack 3. Then, for example, when the cell stack 3 is displaced in the up-down direction Z due to an external force, it interferes with the first portion 40 of the terminal block 4, thereby suppressing the displacement in the up-down direction Z. Also, when the cell stack 3 is displaced in the left-right direction Y due to an external force, it interferes with the second portion 41 of the terminal block 4, thereby suppressing the displacement in the left-right direction Y.

[0046] Furthermore, the terminal block 4 is fixed to the case 2, and is connected to both ends of the cell stack 3 in the stacking direction X via the positive bus bar 33 and the negative bus bar 34, and is fixed to both ends of the cell stack 3 in the stacking direction X, so that the rigidity of the bus bars can be utilized to increase the resistance of the terminal block 4 to displacement. Therefore, the terminal block 4 suppresses displacement of the cell stack 3, and the amount of misalignment of the fuel cell can be kept below an allowable value.

[0047] Furthermore, by arranging the terminal block 4 at a position on the case 2 corresponding to the central portion in the stacking direction X of the cell stack 3 which is most displaced (more specifically, near the central position of the corner formed by the upper cover 22 and the first side wall 23), the amount of displacement of the cell stack 3 can be most efficiently suppressed. If the width at which the displacement of the cell stack 3 reaches its peak is equal to or greater than the width that can be suppressed by the terminal block 4 (in other words, if the width of the terminal block 4 is greater than the width of the displacement peak), the terminal block 4 can suppress the area of ​​the cell stack 3 that should be suppressed.

[0048] Furthermore, since the terminal block 4 also functions as a restricting portion for restricting the displacement of the cell stack 3, there is no need to provide a dedicated part for restricting the displacement, which also has the effect of preventing an increase in costs.

[0049] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various design modifications can be made without departing from the spirit of the present invention as described in the claims. [Explanation of symbols]

[0050] 1: fuel cell stack, 2: case, 3: cell stack, 4: terminal block, 5: connection unit, 21: case body, 22: upper cover, 23: first side wall, 24: second side wall, 25: side opening, 26: top opening, 27: side cover member, 28: top cover member, 31: positive terminal, 32: negative terminal, 33: positive bus bar, 34: negative bus bar, 35: corner, 40: first portion, 41: second portion, 51, 52, 54, 55: connection bus bar, 331, 341: flat plate portion, 332, 342: L-shaped portion

Claims

1. A fuel cell stack comprising: a cell stack formed by stacking a plurality of fuel cell units; and a case for accommodating the cell stack, The cell stack has a positive electrode terminal, a negative electrode terminal, a positive electrode bus bar, and a negative electrode bus bar, one end of the positive bus bar and one end of the negative bus bar are connected to the positive terminal or the negative terminal, and the other ends are extended to a central position of a corner portion formed by a top plate and a side wall of the case so as to be adjacent to each other, the case has a first opening in the top plate at a center position of the corner and a second opening in the side wall at a center position of the corner; a positive bus bar and a negative bus bar that are connectable to the outside of the case via the first opening and the second opening, respectively.

2. 2 . The fuel cell stack according to claim 1 , further comprising a restricting portion fixed to the other end of each of the positive bus bar and the negative bus bar, facing a corner of the cell stack and restricting displacement of the cell stack.

Images