Fuel cell

Abstract

To provide a fuel cell in which ventilation and drainage inside a case can be performed efficiently.SOLUTION: A fuel cell includes: a fuel cell stack including cells stacked in a stacking direction, and a pair of end plates provided at both ends of the stacked cells in the stacking direction to support the stacked cells; and a case housing the fuel cell stack. The case includes: a housing part where the fuel cell stack is disposed; an air intake that takes in outside air; an air outlet; and a drain outlet provided below the air outlet in a vertical direction. A first flow path carrying a fluid from the air intake to the air outlet and a second flow path carrying a fluid from the air intake to the drain outlet are defined between the case and the fuel cell stack. There is provided, at one of the pair of end plates, a branch part branching outside air taken in through the air intake into the first flow path and the second flow path.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] For example, a fuel cell for use in a vehicle has a fuel cell stack in which several hundred power generating cells are stacked to secure electromotive force, and a case that houses the fuel cell stack. Even under normal circumstances, a small amount of hydrogen, which is fuel gas, leaks into the case, and in abnormal circumstances, a large amount of hydrogen may fill the case. Therefore, the case must be appropriately ventilated to prevent an increase in hydrogen concentration. In addition, condensation may occur in the fuel cell case, and the condensed water may adhere to the cells and cause a short circuit. Therefore, the condensed water generated in the case must be appropriately drained. Patent Document 1 and Patent Document 2 disclose a ventilation and drainage structure for a fuel cell stack case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2013-33676 A [Patent Document 2] JP 2017-98066 A Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional ventilation and drainage structures, the paths for air intake into the case and water draining out of the case were not separate, which meant that air and water would flow in opposite directions, raising concerns that ventilation and drainage would interfere with each other.

[0005] An object of the present invention is to provide a fuel cell capable of efficiently ventilating and draining the inside of the case. [Means for solving the problem]

[0006] The fuel cell of the present invention is a fuel cell stack including cells stacked in a stacking direction and a pair of end plates provided at both ends of the stacked cells in the stacking direction to support the stacked cells; a case that houses the fuel cell stack, The case is a housing in which the fuel cell stack is disposed; An intake vent for taking in outside air, An exhaust port, A drain outlet is provided below the exhaust outlet in the up-down direction, a first flow path that conveys a fluid from the intake port to the exhaust port and a second flow path that conveys a fluid from the intake port to the drain port are defined between the case and the fuel cell stack, A branching portion that branches the outside air taken in through the intake port into the first flow path and the second flow path is provided on one of the pair of end plates. Effect of the Invention

[0007] According to the present invention, it is possible to provide a fuel cell capable of efficiently ventilating and draining the water from within the case. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing the entire fuel cell according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Diagram 3] FIG. 3 is a perspective view showing a fuel cell stack of a fuel cell according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view showing a fuel cell stack of a fuel cell according to a third embodiment of the present invention. [Diagram 5] FIG. 5 is a perspective view showing a fuel cell stack of a fuel cell according to a fourth embodiment of the present invention. [Figure 6]FIG. 6 is a front view of the first end plate as viewed from the direction of arrow VI along the stacking direction in FIG. [Figure 7] FIG. 7 is a perspective view showing a fuel cell stack of a fuel cell according to a fifth embodiment of the present invention. [Figure 8] FIG. 8 is a front view of the first end plate as viewed from the direction of arrow VIII along the stacking direction in FIG. [Figure 9] FIG. 9 is a perspective view showing a fuel cell stack of a fuel cell according to a sixth embodiment of the present invention. [Figure 10] FIG. 10 is a front view of the first end plate as viewed from the direction of arrow X along the stacking direction in FIG. [Figure 11] FIG. 11 is a cross-sectional view perpendicular to the left-right direction of a fuel cell according to a seventh embodiment of the present invention. [Figure 12] FIG. 12 is a cross-sectional view perpendicular to the stacking direction of a fuel cell according to an eighth embodiment of the present invention. [Figure 13] FIG. 13 is a cross-sectional view perpendicular to the stacking direction of a fuel cell according to a ninth embodiment of the present invention. [Figure 14] FIG. 14 is a perspective view of a fuel cell according to a tenth embodiment of the present invention. [Figure 15] FIG. 15 is a perspective view of a fuel cell according to an eleventh embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, U represents the upward direction, D represents the downward direction, R represents the rightward direction, L represents the leftward direction, F represents the forward direction, and B represents the backward direction. However, the left-right direction and the forward-backward direction are defined in this specification for the convenience of explaining the present invention, and are not intended to limit the directions during use.

[0010] (First embodiment) FIG. 1 is a schematic diagram showing a fuel cell 100 according to a first embodiment of the present invention. As shown in FIG. 1, the fuel cell 100 has a fuel cell stack 10 and a case 20. In FIG. 1, the fuel cell stack 10 is represented by a solid line, and the case 20 is represented by a dashed line. The fuel cell stack 10 has cells 11 stacked in a stacking direction, and a pair of end plates provided at both ends of the stacked cells 11 in the stacking direction to support the stacked cells 11. The stacking direction is along the front-rear direction in FIG. 1. Note that in FIG. 1, the illustration of the single cells is omitted, and the stacked cells 11 are shown diagrammatically as one component. The pair of end plates are composed of a first end plate 12 and a second end plate 13. The case 20 has a storage section inside, and the fuel cell stack 10 is stored in the storage section of the case 20. The pair of end plates are in contact with the side surfaces of the case 20 in the stacking direction, and the fuel cell stack 10 is supported by the compressive force between the end plates and the side surfaces of the case 20. The fuel cell stack 10 is not in contact with the inner surface of the case other than the side surfaces of the case 20 in the stacking direction. That is, there are spaces above, below, to the left and right of the fuel cell stack 10 in the housing portion of the case 20 .

[0011] The case 20 has an intake port 21 for taking in outside air, an exhaust port 22, and a drain port 23 provided vertically below the exhaust port 22. In the configuration shown in Fig. 1, the intake port 21 is provided on the front side surface 20F of the case 20. The exhaust port 22 is provided in the center of the upper end of the rear side surface 20B of the case 20. The drain port 23 is provided in the center of the lower end of the rear side surface 20B of the case 20.

[0012] The first end plate 12 is in contact with the front side surface 20F of the case 20, and the second end plate 13 is in contact with the rear side surface 20B of the case 20. The first end plate 12 has a first portion 12a facing the front side surface 20F of the case 20 and a second portion 12b facing the stacked cells 11. The first portion 12a of the first end plate 12 is provided with a recess 121 at a position facing the intake port 21. The first portion 12a is further provided with an introduction groove 122 that is in communication with the recess 121 and penetrates in the vertical direction to form an introduction path between the first end plate 12 and the case 20. On the other hand, the second end plate 13 is not provided with either a recess or an introduction groove. The first end plate 12 is provided with manifolds 123 on the left and right sides for supplying fuel gas, oxidant gas (air), or cooling water. Although not shown in FIG. 1, the front side surface 20F of the case 20 is provided with holes at positions corresponding to the manifolds 123 for passing the manifolds 123 through.

[0013] 2 is a cross-sectional view taken along the line II-II in FIG. 1, and is a cross-sectional view perpendicular to the left-right direction of fuel cell 100. Hereinafter, the flow of outside air taken into case 20 from intake port 21 will be described with reference to FIG. 2. First, the outside air taken into case 20 from intake port 21 hits recess 121 provided in first end plate 12. Part of the outside air that hits recess 121 flows upward along the introduction groove 122, and the rest flows downward along the introduction groove 122. That is, recess 121 of first end plate 12 plays the role of a branching part that branches the outside air taken in from intake port 21 into different directions.

[0014] Two dashed arrows shown in Fig. 2 indicate flows F1 and F2, which are flows of outside air taken in from the intake port 21. In the illustrated example, the flow F1 is a flow in which the outside air taken in from the intake port 21 collides with the recess 121 (branching portion), then flows upward in the introduction path, is led to the upper interior of the case 20, passes above the fuel cell stack 10, and flows toward the exhaust port 22. The first flow path P1 is defined as the flow path through which the flow F1 passes. The flow F2 is a flow in which the outside air taken in from the intake port 21 collides with the recess 121, then flows downward in the introduction path, is led to the lower interior of the case 20, passes below the fuel cell stack 10, and flows toward the drain port 23. The second flow path P2 is defined as the flow path through which the flow F2 passes.

[0015] Water vapor and hydrogen are present inside the case 20. Because water vapor and hydrogen are lighter than air, they tend to accumulate in the upper part of the inside of the case 20. Outside air flowing through the first flow path P1 is pushed out to the exhaust port 22 together with water vapor and hydrogen, which are fluids present inside the case 20. By introducing outside air into the first flow path P1 in this manner, it is possible to exhaust water vapor and hydrogen to the outside of the case 20, and the inside of the case 20 can be ventilated.

[0016] As described above, water vapor is generated inside the case 20, so the humidity is high. In addition, as the fuel cell 100 operates, a temperature difference occurs inside the case 20, so condensation is likely to occur. The condensed water generated inside the case 20 accumulates on the inner bottom surface of the case 20. The flow F2 passing through the second flow path P2 pushes the condensed water, which is a fluid present on the inner bottom surface of the case 20, toward the drain outlet 23. Therefore, by introducing outside air into the second flow path P2, the discharge of the condensed water is promoted.

[0017] According to this embodiment, the outside air taken in from the intake port 21 branches into the first flow path P1 and the second flow path P2 by the recess 121 (branching portion), and flows to the exhaust port 22 and the drain port 23. With this configuration, the fluids flowing in different directions do not obstruct each other. Therefore, ventilation and drainage inside the case can be performed efficiently.

[0018] In this embodiment, the distance between the air intake 21 and the first end plate 12 in the stacking direction is smaller than the distance between the exhaust port 22 and the first end plate 12. That is, the air intake 21 is provided on the side closer to the first end plate 12, and the exhaust port 22 is provided on the side farther from the first end plate 12. This allows efficient ventilation inside the case 20. Also, the distance between the air intake 21 and the first end plate 12 in the stacking direction is smaller than the distance between the drain port 23 and the first end plate 12. That is, the air intake 21 is provided on the side closer to the first end plate 12, and the drain port 23 is provided on the side farther from the first end plate 12. This allows condensation water generated inside the case 20 to be efficiently drained.

[0019] In this embodiment, the drain outlet 23 is provided at the lower part of the case 20, so that condensation water generated in the case 20 can be efficiently drained. In this embodiment, the drain outlet 23 is provided at the center of the lower end of the rear side surface 20B of the case 20 with which the second end plate 13 contacts, but the location of the drain outlet 23 is not particularly limited as long as it is at the lower part of the case 20. The lower part of the case 20 means the lower half when the case 20 is divided into two parts, upper and lower. The drain outlet 23 is preferably provided at the lower end of the lower surface of the case 20 or the side surface of the case 20. When the drain outlet 23 is provided at the lower part of the case 20, drainage can be performed by appropriately providing a flow path regardless of where the drain outlet 23 is provided at the lower part of the case 20, but it is preferable to provide the drain outlet 23 on the opposite side to the side surface on which the air intake 21 is provided, that is, on the side closer to the rear side surface 20B. When drain outlet 23 is provided on the side of case 20, drainage can be achieved by appropriately providing a flow path regardless of which side of case 20 drain outlet 23 is provided on, but it is preferable to provide drain outlet 23 on the side opposite to the side on which air intake port 21 is provided, i.e., the rear side 20B.

[0020] There is no particular limitation on the method of introducing outside air into the case 20 from the air intake 21. For example, outside air may be introduced by pressurizing the air intake 21 using a blower or the wind generated by running, or outside air may be introduced from the air intake 21 by creating negative pressure on the exhaust port 22 and drain port 23 sides using the wind generated by running.

[0021] Second embodiment Next, a fuel cell according to a second embodiment of the present invention will be described. In the following description, components common to the embodiments already described will be given the same reference numerals, and description thereof will be omitted. Fig. 3 is a perspective view showing a fuel cell stack 210 of a fuel cell according to the second embodiment. The case of the fuel cell according to this embodiment may be the same as the case 20 of the first embodiment. Illustration of the case is omitted in Fig. 3.

[0022] A fuel cell stack 210 of the fuel cell according to the second embodiment includes a first upper region 212a and a second upper region 212b located closer to the cell 11 side than the first upper region 212a on the upper surface of a first end plate 212 having a recess 121 (branch portion). The second upper region 212b is higher than the first upper region 212a.

[0023] Condensation may occur inside the case 20. If the condensation comes into contact with the cells 11, the cells 11 may short-circuit, resulting in problems such as a decrease in power generation efficiency. According to this embodiment, the presence of the elevated second upper region 212b on the cell 11 side can prevent the condensation generated on the upper surface of the first end plate 212 from being blown to the cell 11 side by the flow F1 of outside air moving upward through the introduction path. Therefore, a short circuit of the cells 11 can be prevented. In addition, as shown in FIG. 3, if a step exists on the upper surface of the first end plate 212, a part of the outside air branches off from the flow F1 and generates a flow F3 that flows from the center in the left-right direction to both ends along the step. This flow F3 that flows from the center in the left-right direction to both ends pushes the condensation generated on the upper surface of the first end plate 212 to the left and right, so that the condensation can be efficiently removed.

[0024] 3, there is a step between the first upper region 212a and the second upper region 212b, but the present invention is not limited to such a configuration, and for example, the upper surface of the first end plate 212 may be a slope with an upward gradient toward the cell 11 side. In this configuration, the lower part of the sloped upper surface of the first end plate 212 on the intake port 21 side can be regarded as the first upper region 212a, and the higher part on the cell 11 side can be regarded as the second upper region 212b. With this configuration, it is possible to prevent condensed water from being splashed toward the cell 11 side, and to prevent a short circuit of the cell 11.

[0025] Third embodiment 4 is a perspective view showing a fuel cell stack 310 of a fuel cell according to a third embodiment of the present invention. The fuel cell stack 310 has a first end plate 312 instead of the first end plate 212 in the fuel cell stack 210 of the second embodiment. The first end plate 312 has a first upper region 312a that has a downward slope from the center to both ends in the left-right direction.

[0026] According to this embodiment, because the first upper region 312a has a slope, the condensation water generated on the upper surface of the first end plate 312 can be more efficiently drained from the center to both the left and right ends. This prevents the condensation water from being splashed toward the cells 11 and promotes drainage.

[0027] (Fourth embodiment) FIG. 5 is a perspective view showing a fuel cell stack 410 of a fuel cell according to a fourth embodiment of the present invention. FIG. 6 is a front view of a first end plate 412 as viewed from the direction of an arrow VI along the stacking direction in FIG. 5. The first end plate 412 has a first upper region 412a and a second upper region 412b located closer to the cell 11 side than the first upper region 412a. In the fuel cell according to the fourth embodiment, an upper horizontal flow path Pu is provided above the first upper region 412a, which is connected to the introduction passage and extends in the left-right direction, and an up-down flow path Ps is provided between both left-right ends of the first end plate 412 and the inner surface of the case 20, which is connected to the upper horizontal flow path Pu and extends in the up-down direction. That is, in the fourth embodiment, steps are provided on the upper surface and both left-right ends of the first end plate 412.

[0028] In the fourth embodiment, the fluid flow F3 branching off from the first flow path P1 to the upper horizontal flow path Pu passes through the upper and lower flow paths Ps toward the inner underside of the case 20, merges with the flow F2 passing through the second flow path P2 at the inner underside of the case 20, and is led to the drain outlet.

[0029] According to this embodiment, a flow path is formed that runs from the center of the upper part of first end plate 412 through both left and right ends to the bottom surface inside the case, thereby promoting drainage of condensation water that forms on the upper part of first end plate 412.

[0030] 5 and 6, the upper horizontal flow passage Pu has a downward gradient from the introduction passage toward both ends in the left-right direction, but the upper horizontal flow passage Pu does not have to have a gradient. However, if the upper horizontal flow passage Pu has a downward gradient from the introduction passage toward both ends in the left-right direction, it is preferable because the condensation water on the first upper region 412a can be efficiently flowed to the up-down flow passage Ps.

[0031] Fifth embodiment Fig. 7 is a perspective view showing a fuel cell stack 510 of a fuel cell according to a fifth embodiment of the present invention. Fig. 8 is a front view of a first end plate 512 as viewed from the direction of arrow VIII along the stacking direction in Fig. 7. In addition to the upper horizontal flow path Pu and the up-down flow paths Ps, the first end plate 512 further has a lower horizontal flow path Pd between the lower surface of the first end plate 512 and the inner surface of the case 20, which extends in the left-right direction and is connected to the up-down flow paths Ps and the introduction path. That is, in the fifth embodiment, in addition to the upper surface and both left-right ends of the first end plate 512, steps are provided on the lower surface of the first end plate 512 as well.

[0032] According to this embodiment, the flow F3 passing through the upper horizontal flow passage Pu and the up-down flow passage Ps further passes through the lower horizontal flow passage Pd from both left-right ends toward the center of the lower part, facilitating the drainage of condensed water inside the case 20. As shown in Fig. 7, outside air moving in the stacking direction is introduced into the lower horizontal flow passage Pd from the air intake 21, and the outside air that hits the step becomes an air flow Fd moving downward, which pushes the condensed water formed on the lower surface of the first end plate 512 downward. This allows the condensed water formed on the lower surface of the first end plate 512 to be efficiently drained.

[0033] In the fifth embodiment, the lower horizontal flow passage Pd does not necessarily extend horizontally in the left-right direction, and may have a gradient. The lower horizontal flow passage Pd preferably has a downward gradient from both left-right ends toward the introduction passage.

[0034] Sixth embodiment Fig. 9 is a perspective view showing a fuel cell stack 610 of a fuel cell according to a sixth embodiment of the present invention, and Fig. 10 is a front view of a first end plate 612 as viewed from the direction of arrow X along the stacking direction in Fig. 9. In the fuel cell stack 610, the lower surface of the first end plate 612 has a downward slope from both ends in the left-right direction perpendicular to both the stacking direction and the up-down direction towards the introduction path.

[0035] According to this embodiment, the underside of first end plate 612 has a slope, which makes it easier for condensed water adhering to the underside of first end plate 612 to flow toward the inlet path side where the current is stronger, facilitating drainage.

[0036] In the configuration shown in FIG. 9, a step is provided on the lower surface of the first end plate 612, but the step on the lower surface may not be provided. However, if a step is provided, the outside air that hits the step generates an air flow Fd that pushes condensation water generated on the lower surface of the first end plate 612 downward, which is preferable because efficient drainage can be achieved. In addition, although steps are provided on the upper surface and side surface of the first end plate 612, steps on the upper surface and side surface may not be provided. However, as explained in the above-mentioned fifth embodiment, if steps are provided on each of the upper surface, side surface, and lower surface of the first end plate 612, the upper horizontal flow path Pu, the up-down flow path Ps, and the lower horizontal flow path Pd are formed, which is preferable because drainage can be promoted. In addition, in the configuration shown in FIG. 9, the upper horizontal flow path Pu formed on the first end plate 612 has a downward gradient from the introduction path toward both left and right ends, but it may not have a gradient. However, as explained in the above-mentioned fourth embodiment, if the upper horizontal flow path Pu has a downward gradient from the introduction path toward both left and right ends, it is preferable because condensation water on the first end plate 612 can be efficiently drained to the up-down flow path Ps.

[0037] Seventh embodiment 11 is a cross-sectional view perpendicular to the left-right direction of a fuel cell 700 according to a seventh embodiment of the present invention. The fuel cell 700 has a case 720 instead of the case 20 of the first embodiment. The case 720 has a different inner shape from the case 20. Specifically, an inner upper surface 724 of the case 720 has an upward slope in the direction along the first flow path P1, and an inner lower surface 725 of the case 720 has a downward slope in the direction along the second flow path P2.

[0038] According to this embodiment, hydrogen and water vapor, which are lighter than air, flow toward exhaust port 22 along the gradient of inner upper surface 724 of case 720, thereby promoting ventilation. Also, condensed water flows toward drain port 23 along the gradient of inner lower surface 725 of case 720, thereby promoting drainage.

[0039] Eighth embodiment FIG. 12 is a cross-sectional view perpendicular to the stacking direction of a fuel cell 800 according to an eighth embodiment of the present invention. The fuel cell 800 has a case 820 instead of the case 20 of the first embodiment. An inner upper surface 824 of the case 820 is configured as a curved surface that is convex upward in a cross section perpendicular to the stacking direction. In the example shown in FIG. 12, the inner upper surface 824 has a linear upward slope from both the left and right ends toward the center. Note that the exhaust port 22 and the drain port 23 do not actually appear in the cross section of the fuel cell 800 shown in FIG. 12, but are shown by dashed lines to clearly indicate the positions of the exhaust port 22 and the drain port 23.

[0040] According to this embodiment, the condensation water adhering to the inner upper surface 824 of the case 820 is guided to the side surface of the case 820, so that the condensation water can be prevented from falling onto the cell 11. Therefore, it is possible to prevent a short circuit of the cell 11 and promote drainage inside the case 820. Furthermore, in the example shown in FIG. 12, the exhaust port 22 is provided at the center in the left-right direction, which is the apex of the inner upper surface 824 of the case 820, so that ventilation can be performed efficiently. Note that the "bent surface" here is not limited to the bent surface as shown in FIG. 12, but may be a smoothly curved surface. In addition, the inner upper surface 824 of the case 820 in FIG. 12 is upwardly convex in a cross section perpendicular to the stacking direction, but the inner upper surface 824 may be upwardly convex in a cross section perpendicular to the left-right direction, or may be upwardly convex in both a cross section perpendicular to the stacking direction and a cross section perpendicular to the left-right direction.

[0041] Ninth embodiment FIG. 13 is a cross-sectional view perpendicular to the stacking direction of a fuel cell 900 according to a ninth embodiment of the present invention. The fuel cell 900 has a case 920 instead of the case 20 of the first embodiment. At the position of the exhaust port 22 in FIG. 13, there is a flow F1 passing through the first flow path P1 from the front to the back of the paper, and at the position of the drain port 23, there is a flow F2 passing through the second flow path P2 from the front to the back of the paper. The inner upper surface 924 of the case 920 has an upward gradient from both ends in the left-right direction toward the first flow path P1, and the inner lower surface 925 of the case 920 has a downward gradient from both ends in the left-right direction toward the second flow path P2. Note that the exhaust port 22 and the drain port 23 do not actually appear in the cross section of the fuel cell 900 shown in FIG. 13, but in FIG. 13, the exhaust port 22 and the drain port 23 are illustrated by dashed lines to clearly show the flow paths.

[0042] According to this embodiment, it is possible to promote ventilation because hydrogen and water vapor, which are lighter than air, move along the inner upper surface 924 of the case 920, merge with the flow F1 passing through the first flow path P1, and flow to the exhaust port 22. In addition, it is possible to promote drainage because condensed water moves along the inner lower surface 925 of the case 920, merges with the flow F2 passing through the second flow path P2, and flows to the drain port 23.

[0043] Tenth embodiment 14 is a perspective view of a fuel cell 1000 according to a tenth embodiment of the present invention. The fuel cell 1000 has a case 1020 instead of the case 20 of the first embodiment. The case 1020 has an exhaust port 1022 and a drain port 1023, and the exhaust port 1022 is larger than the drain port 1023. This makes the airflow resistance of the exhaust port 1022 smaller than the airflow resistance of the drain port 1023.

[0044] According to this embodiment, more outside air is exhausted from the exhaust port 1022 than from the drain port 1023. Therefore, part of the flow F2 toward the drain port 1023 turns upward along the left and right inner side surfaces of the case 1020, merges with the flow F1, and is exhausted from the exhaust port 1022. This promotes ventilation. In the example of FIG. 14, the ventilation resistance is adjusted by adjusting the sizes of the exhaust port 1022 and the drain port 1023, but this is not the only possible embodiment. For example, the ventilation resistance may be adjusted by adjusting the diameter of a duct connected to the exhaust port or the drain port.

[0045] Eleventh embodiment 14 is a perspective view of a fuel cell 1100 according to an eleventh embodiment of the present invention. The fuel cell 1100 has a case 1120 instead of the case 20 of the first embodiment. The case 1120 has an exhaust port 1122 and a drain port 1123, and the drain port 1123 is larger than the exhaust port 1122. This makes the airflow resistance of the drain port 1123 smaller than the airflow resistance of the exhaust port 1122.

[0046] According to this embodiment, more outside air is exhausted from the drain port 1123 than from the exhaust port 1122. Therefore, part of the flow F1 toward the exhaust port 1122 turns downward along the left and right inner side surfaces of the case 1120, thereby allowing condensation water generated on the inner side surfaces of the case 1120 to flow downward. The airflow that turns downward merges with the flow F2 and is exhausted from the drain port 1123 together with the condensation water, promoting drainage. As in the tenth embodiment, the method of adjusting the airflow resistance is not limited to the method of adjusting the size of the exhaust port 1122 and the drain port 1123.

[0047] Although the present invention has been described above by way of examples of specific embodiments, the present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0048] In the above embodiment, the manifold is provided on the first end plate, but the manifold may be provided on the second end plate.

[0049] The present invention includes the following. (1) a fuel cell stack including cells stacked in a stacking direction and a pair of end plates provided at both ends of the stacked cells in the stacking direction to support the stacked cells; a case that houses the fuel cell stack, The case is a housing in which the fuel cell stack is disposed; An intake vent for taking in outside air, An exhaust port, A drain outlet is provided below the exhaust outlet in the up-down direction, a first flow path that conveys a fluid from the intake port to the exhaust port and a second flow path that conveys a fluid from the intake port to the drain port are defined between the case and the fuel cell stack, a branching portion that branches the outside air taken in through the intake port into the first flow path and the second flow path, the branching portion being provided on one of the pair of end plates. (2) the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, a distance between the intake port and the first end plate in the stacking direction is smaller than a distance between the exhaust port and the first end plate; The fuel cell according to (1). (3) the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, a distance between the air intake port and the first end plate in the stacking direction is smaller than a distance between the air drain port and the first end plate; A fuel cell according to (1) or (2). (4) The fuel cell according to any one of (1) to (3), wherein the drain outlet is provided in a lower portion of the case. (5) the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, A first upper region and a second upper region located on the cell side relative to the first upper region are provided on an upper surface of the first end plate, The fuel cell according to any one of (1) to (4), wherein the second upper region is higher than the first upper region. (6) The fuel cell according to (5), wherein in a cross section perpendicular to the stacking direction, the first upper region has a downward slope from the center toward both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction. (7) an introduction groove is provided on a surface of the first end plate opposite to the stacked cells, the introduction groove penetrating in the vertical direction and forming an introduction path between the first end plate and the case; an upper horizontal flow path is provided above the first upper region, the upper horizontal flow path being connected to the introduction path and extending in a left-right direction perpendicular to both the stacking direction and the up-down direction; Between a side surface of the first end plate and an inner surface of the case, there is an upper and lower flow passage connected to the upper horizontal flow passage and extending in the vertical direction. A fuel cell according to (5) or (6). (8) The fuel cell according to (7), wherein a lower horizontal flow passage extending in the left-right direction and connected to the upper and lower flow passages and the inlet passage is located between the lower surface of the first end plate and the inner surface of the case. (9) the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, an introduction groove is provided on a surface of the first end plate opposite to the stacked cells, the introduction groove penetrating in the vertical direction and forming an introduction path between the first end plate and the case; A fuel cell described in any one of (1) to (8), wherein the lower surface of the first end plate has a downward slope from both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction toward the introduction path. (10) The inner upper surface of the case has an upward slope in a direction along the first flow path, The fuel cell according to any one of (1) to (9), wherein the inner lower surface of the case has a downward slope in a direction along the second flow path. (11) The fuel cell according to any one of (1) to (10), wherein in a cross section perpendicular to the stacking direction, the inner upper surface of the case is configured as an upwardly convex curved surface. (12) A fuel cell described in any one of (1) to (11), wherein the inner upper surface of the case has an upward slope from both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction toward the first flow path, and the inner lower surface of the case has a downward slope from both ends in the left-right direction toward the second flow path. (13) The fuel cell according to any one of (1) to (12), wherein the airflow resistance of the exhaust port is smaller than the airflow resistance of the drain port. (14) The fuel cell according to any one of (1) to (12), wherein the drain port has a smaller airflow resistance than the exhaust port. [Explanation of symbols]

[0050] 100,700,800,900,1000,1100 fuel cell 10,210,310,410,510,610 Fuel Cell Stack 11 Cell 12,212,312,412,512,612 First end plate 12a First part 12b Second part 121 Concave (branch) 122 Introduction groove 123 Manifold 13 Second End Plate 20,720,820,920,1020,1120 Case 20F Front Side 20B Rear Side 21 Intake Port 22,1022,1122 Exhaust Port 23,1023,1123 Drain Port 212a,312a,412a First Upper Region 212b,412b Second Upper Region 724,824,924 Inner Upper Surface 725,925 Inner Lower Surface P1 First Flow Path P2 Second Flow Path Pu Upper Horizontal Flow Path Ps Vertical Flow Path Pd Lower Horizontal Flow Path F1,F2,F3 Flow Fd Air Flow

Claims

1. a fuel cell stack including cells stacked in a stacking direction and a pair of end plates provided at both ends of the stacked cells in the stacking direction to support the stacked cells; a case that houses the fuel cell stack, The case is a housing in which the fuel cell stack is disposed; An intake vent for taking in outside air, An exhaust port, A drain outlet is provided below the exhaust outlet in the up-down direction, a first flow path that conveys a fluid from the intake port to the exhaust port and a second flow path that conveys a fluid from the intake port to the drain port are defined between the case and the fuel cell stack, a branching portion that branches the outside air taken in through the intake port into the first flow path and the second flow path, the branching portion being provided on one of the pair of end plates.

2. the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, a distance between the intake port and the first end plate in the stacking direction is smaller than a distance between the exhaust port and the first end plate; The fuel cell according to claim 1 .

3. the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, a distance between the air intake port and the first end plate in the stacking direction is smaller than a distance between the air drain port and the first end plate; The fuel cell according to claim 1 or 2.

4. 3. The fuel cell according to claim 1, wherein the drain outlet is provided in a lower portion of the case.

5. the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, A first upper region and a second upper region located on the cell side relative to the first upper region are provided on an upper surface of the first end plate, 3. The fuel cell according to claim 1 or 2, wherein the second upper region is higher than the first upper region.

6. 6. The fuel cell according to claim 5, wherein in a cross section perpendicular to the stacking direction, the first upper region has a downward slope from the center toward both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction.

7. an introduction groove is provided on a surface of the first end plate opposite to the stacked cells, the introduction groove penetrating in the vertical direction and forming an introduction path between the first end plate and the case; an upper horizontal flow path is provided above the first upper region, the upper horizontal flow path being connected to the introduction path and extending in a left-right direction perpendicular to both the stacking direction and the up-down direction; Between a side surface of the first end plate and an inner surface of the case, there is an upper and lower flow passage connected to the upper horizontal flow passage and extending in the vertical direction. The fuel cell according to claim 5.

8. 8. The fuel cell according to claim 7, wherein a lower horizontal flow passage extending in the left-right direction and connected to the upper and lower flow passages and the introduction passage is disposed between a lower surface of the first end plate and an inner surface of the case.

9. the pair of end plates includes a first end plate having the branch portion and a second end plate not having the branch portion, an introduction groove is provided on a surface of the first end plate opposite to the stacked cells, the introduction groove penetrating in the vertical direction and forming an introduction path between the first end plate and the case; 3. The fuel cell according to claim 1, wherein a lower surface of the first end plate has a downward slope from both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction toward the introduction passage.

10. The inner upper surface of the case has an upward slope in a direction along the first flow path, 3. The fuel cell according to claim 1, wherein the inner lower surface of the case has a downward slope in a direction along the second flow path.

11. 3. The fuel cell according to claim 1, wherein in a cross section perpendicular to the stacking direction, an inner upper surface of the case is configured as an upwardly convex curved surface.

12. 3. The fuel cell described in claim 1 or claim 2, wherein the inner upper surface of the case has an upward slope from both ends in a left-right direction perpendicular to both the stacking direction and the up-down direction toward the first flow path, and the inner lower surface of the case has a downward slope from both ends in the left-right direction toward the second flow path.

13. 3. The fuel cell according to claim 1, wherein the airflow resistance of the exhaust port is smaller than the airflow resistance of the drain port.

14. 3. The fuel cell according to claim 1, wherein the drain port has a smaller airflow resistance than the exhaust port.

Images