JP6804884B2 - Fuel cell stack - Google Patents

Description

The present invention relates to a fuel cell stack.

It is known to supply a refrigerant to a fuel cell to control the temperature of the fuel cell (Patent Document 1).

Japanese Unexamined Patent Publication No. 2016-096658

Usually, the fuel cell is put into practical use as a fuel cell stack having a stack structure consisting of a plurality of cells. A flow path is formed in the fuel cell stack to cool the fuel cell stack with cooling water. A part of this flow path is a supply and discharge manifold for flowing cooling water to a portion corresponding to the power generation surface of each cell.

The cooling water may be discharged from the above flow path for inspection and maintenance of the fuel cell stack. After inspection and maintenance, the flow path is filled with cooling water again. At this time, it is preferable that air does not remain in the flow path as much as possible. If air remains in the flow path, the air may flow into the pump that circulates the cooling water during the operation of the fuel cell, which may deteriorate the pump performance.

By the way, the fuel cell stack is mounted in various postures. For example, it may be mounted in an inclined posture so that the generated water generated by the power generation reaction can be drained smoothly. As a result, the outlet of the discharge manifold may point slightly downward. The fact that the outlet points slightly downward means that the upstream end of the discharge manifold is located above the outlet. Therefore, air tends to collect at the upstream end of the discharge manifold, which may affect the pump performance as described above.

Even if the fuel cell stack is mounted in a posture that the outlet faces slightly downward, if the posture of the fuel cell stack is changed so that the outlet faces upward when filling the cooling water, it will be located at the upstream end of the discharge manifold. The accumulated air can be discharged. However, it is preferable to avoid changing the posture in this way because it increases the man-hours for inspection and maintenance.

Further, the above problem becomes more remarkable when the outlet is mounted so as to face directly downward. Based on the above, an object of the present invention is to facilitate the discharge of air from the discharge manifold.

The present invention is for solving the above problems and can be realized as the following forms.

One embodiment of the present invention includes a cell laminate in which a plurality of cells are laminated; a discharge manifold for discharging cooling water from the cell laminate; and a pipe arranged in the discharge manifold and having both ends open. One end of both ends of the pipe is located near the outlet of the discharge manifold; the other end of both ends of the pipe is located upstream of the discharge manifold. It is a fuel cell stack. According to this form, when the cooling water is injected into the flow path of the cooling water, the air flows from the other end of the pipe toward one end, so that the air is discharged from the outlet of the discharge manifold through one end of the pipe. Will be done. Therefore, the air near the other end of the pipe is easily discharged from the discharge manifold. The air flows from the other end of the pipe toward one end because the pressure at the other end is higher than that at one end due to the pressure loss caused by the flow of the cooling water in the discharge manifold.

The present invention can be realized in various forms other than the above. For example, it can be realized in the form of an exhaust method from the fuel cell stack.

The perspective view which shows the schematic structure of the fuel cell stack. The plan view which shows the cathode side separator. Enlarged view near the exit. A cross-sectional view taken along the line AA shown in FIG. A cross-sectional view showing a modified example pipe. A cross-sectional view of AA when mounted in a flat stack.

FIG. 1 is a perspective view showing a schematic configuration of the fuel cell stack 500. The fuel cell stack 500 is mounted on an automobile. The fuel cell stack 500 includes a cell laminate 300A (code is shown in FIG. 4). The cell laminate 300A is formed by laminating a plurality of cells 300 along the stacking direction SD. The cell 300 is a polymer electrolyte fuel cell.

Six manifolds 1 to 6 are formed inside the fuel cell stack 500. The fuel gas supply manifold 1 is a flow path for supplying hydrogen gas to each cell 300 from the outside of the fuel cell stack 500. The fuel gas discharge manifold 2 is a flow path for discharging the anode off gas discharged from each cell 300 to the outside of the fuel cell stack 500. The oxidant gas supply manifold 3 is a flow path for supplying air to each cell 300 from the outside of the fuel cell stack 500. The oxidant gas discharge manifold 4 is a flow path for discharging the cathode off gas discharged from each cell 300 to the outside of the fuel cell stack 500. The cooling water supply manifold 5 is a flow path for supplying cooling water from the outside of the fuel cell stack 500 to the power generation corresponding portion 210 (FIG. 2) of each cell 300. The cooling water discharge manifold 6 is a flow path for discharging the cooling water discharged from the power generation corresponding portion 210 of each cell 300 to the outside of the fuel cell stack 500. Each of the six manifolds 1 to 6 is an internal manifold whose longitudinal direction is parallel to the stacking direction SD.

Each cell 300 includes a MEGA plate 280, a cathode side separator 100c, and an anode side separator 100a. MEGA is an acronym for Membrane Electrode and Gas diffusion layer assembly, which means a membrane electrode gas diffusion assembly. The cathode side separator 100c and the anode side separator 100a are a pair of separators arranged so as to sandwich the MEGA plate 280 along the stacking direction.

The MEGA plate 280 includes a MEGA 200 and a support frame 250. The MEGA 200 has a configuration in which a solid polymer electrolyte membrane, an anode-side catalyst electrode layer, a cathode-side catalyst electrode layer, an anode-side gas diffusion layer, and a cathode-side gas diffusion layer are laminated in the stacking direction SD. A through hole is provided in the central portion of the support frame 250 in the thickness direction, and the MEGA 200 is arranged in the through hole.

The pair of separators are arranged so as to sandwich the MEGA plate 280 in the stacking direction SD. The cathode side separator 100c is a thin plate member having a substantially rectangular shape, and uneven shapes are formed on both sides of the SD in the stacking direction. Due to this uneven shape, an in-cell gas flow path through which the reaction gas (fuel gas or oxidant gas) flows is formed, and further, a cooling water flow path is formed between the anode-side separator 100a of the adjacent cell 300. .. The cathode side separator 100c is provided with six substantially rectangular openings 11 to 16 at predetermined positions on the outer peripheral portion. The opening 15 is also referred to as a supply opening. The opening 16 is also referred to as a discharge opening. When the fuel cell stack 500 is assembled by stacking a plurality of cells 300, the openings 11 to 16 of the cells 300 overlap with the stacking direction SD, whereby the above-mentioned six manifolds 1 to 6 are formed.

A sealing member 30 is interposed between the adjacent cells 300, more specifically, between the two adjacent separators 100c and 100a of each cell 300 for the purpose of preventing leakage of reaction gas, cooling water, or the like. .. The seal member 30 includes a first seal member 30a, a second seal member 30b, a third seal member 30c, a fourth seal member 30d, and a fifth seal member 30e. The first seal member 30a to the fourth seal member 30d are all frame-shaped members having a substantially rectangular shape in a plan view. The fifth seal member 30e is a frame-shaped member having a substantially cross-shaped plan view. The first seal member 30a is arranged so as to surround the opening 11. Similarly, the second seal member 30b surrounds the opening 12, the third seal member 30c surrounds the opening 13, and the fourth seal member 30d surrounds the opening 14. The fifth seal member 30e is arranged so as to surround the parts of the two openings 15 and 16 and the separator 100 corresponding to the MEGA 200. The portion corresponding to MEGA200 is a portion corresponding to MEGA200 on the surface opposite to the surface in contact with MEGA200. In the MEGA 200, the surface in contact with the separator 100 is a power generation surface. Therefore, the portion corresponding to the above MEGA200 is a portion corresponding to the power generation surface.

Here, the XYZ coordinate system is defined as the Cartesian coordinate system of the right-handed system. The Y direction is parallel to the stacking direction SD, and the direction from the side where the openings 11 to 16 of the six manifolds 1 to 6 are arranged to the inside of the fuel cell stack 500 is positive. The X direction is parallel to the long side direction of the contour of the cell 300, and the direction from the cooling water discharge manifold 6 to the cooling water supply manifold 5 is positive. The Z direction is parallel to the short side direction of the contour of the cell, and the direction from the fuel gas discharge manifold 2 to the oxidant gas discharge manifold 4 is positive. As shown in FIG. 1, the opening 16 of the cell 300 located on the minus side in the Y direction is also referred to as an outlet 16a.

As shown in FIG. 1, a pipe 400 is provided in the cooling water discharge manifold 6. The pipe 400 will be described with reference to FIGS. 3 and 4.

FIG. 2 is a plan view showing the configuration of the cathode side separator 100c. In the cathode side separator 100c, one surface faces the MEGA plate 280, and the other surface faces the anode side separator 100a of the adjacent cells 300 via the sealing member 30. FIG. 2 shows the surface of both sides of the cathode side separator 100c facing the anode side separator 100a of the adjacent cells 300. The shape of the cathode side separator 100c has a plane symmetric relationship with the shape of the anode side separator 100a. Therefore, the cathode side separator 100c will be described as a representative.

As shown in FIG. 2, the cathode side separator 100c includes six wall portions 20a to 20f in addition to the six openings 11 to 16 described above. All of the six wall portions 20a to 20f project in the direction (minus direction in the Y direction) of the adjacent cells 300 toward the anode side separator 100a. These wall portions 20a to 20f are formed in order to prevent the seal member 30 from being largely displaced. The wall portion 20a is arranged so as to surround the outer peripheral portion of the opening 11. The wall portion 20b is arranged so as to surround the outer peripheral portion of the opening 12, the wall portion 20c is arranged so as to surround the outer peripheral portion of the opening 13, and the wall portion 20d is arranged so as to surround the outer peripheral portion of the opening 14. The wall portion 20e is arranged so as to surround a region including two openings 15 and 16 and a portion 210 (hereinafter, referred to as a power generation corresponding portion 210) corresponding to a portion of the cathode side separator 100c in contact with the MEGA 200. The wall portion 20f is arranged along the outer edge of the cathode side separator 100c in the vicinity of the outer edge.

In the cathode side separator 100c, a plurality of flow paths 111 extending along the X-axis direction and a plurality of protrusions 112 arranged at both ends of the flow path 111 are arranged in the power generation corresponding portion 210. There is. The flow path 111 is a flow path for cooling water in the power generation corresponding portion 210, and is formed by a plurality of ribs parallel to each other. Similar ribs are provided on the surface of the adjacent anode-side separator 100a facing the cathode-side separator 100c (not shown). Therefore, in a state where the cells 300 are stacked, the flow paths 111 of the two facing separators 100c and 100a face each other, and a cooling water flow path is formed between the two adjacent separators 100c and 100a. .. Of the protrusions 112, the protrusion 112 on the plus side in the X direction disperses the cooling water flowing from the opening 15 into the power generation corresponding portion 210 in the Z-axis direction. Further, the cooling water discharged from the protrusion 112 on the minus side in the X direction to the opening 16 is collected in the direction toward the opening 16.

FIG. 3 is an enlarged view of the vicinity of the exit 16a. As shown in FIG. 2, the pipe 400 is fixed to the corner of the cooling water discharge manifold 6 by the support portion 410. The corners to which the pipe 400 is fixed are the corners on the minus side in the X direction and the corners on the plus side in the Z direction. Therefore, when the positive side in the Z direction coincides upward in the vertical direction, the pipe 400 is installed at the highest position in the vertical direction in the cooling water discharge manifold 6. The support portion 410 is provided on each of the anode side separator 100a, the cathode side separator 100c, and the support frame 250.

FIG. 4 is a cross-sectional view taken along the line AA shown in FIG. In FIG. 4, instead of showing the cells 300 separately one by one, they are collectively shown as a cell laminated body 300A which is a laminated body of the cells 300. FIG. 4 shows terminal plates 260 and 265 and insulating plates 270 as components of the fuel cell stack 500, in addition to the cell laminate 300A and the pipe 400.

As shown in FIG. 4, the Z direction does not coincide with the vertical direction. This indicates that the fuel cell stack 500 according to the present embodiment is mounted at an angle. The inclination referred to here is based on the surface in contact with the four tires of the automobile equipped with the fuel cell stack 500. The purpose of tilting and mounting is to smooth the discharge of generated water due to the reaction between the anode gas and the cathode gas when the four tires are in contact with the horizontal plane. As a result of the tilted installation, the exit 16a faces slightly downward as shown in FIG.

The pipe 400 is a pipe that is open at both ends and extends straight along the Y direction. The opening end 408, which is one end of the pipe 400, is arranged near the outlet 16a. The open end 404, which is the other end of the pipe 400, is arranged so as to contact the terminal plate 260. Therefore, the opening end 404 is located on the upstream side of the cooling water discharge manifold 6 with respect to the opening end 408.

The open end 404 has a notch 405. Therefore, the fluid in the cooling water discharge manifold 6 can flow into the pipe 400 through the opening end 404. The notch 405 is provided at a position on the positive side of the opening end 404 in the Z direction.

In FIG. 4, while the operation of the fuel cell stack 500 is stopped, most of the cooling water is discharged from the fuel cell stack 500, and then the cooling water flow path is to be filled with the cooling water again. Shows the progress of the work process. Cooling water is injected from the cooling water supply manifold 5 in order to fill the flow path with the cooling water. The cooling water injected from the cooling water supply manifold 5 passes through the portion corresponding to the power generation surface of each cell 300 and flows into the cooling water discharge manifold 6. FIG. 4 shows a state in which a part of the cooling water discharge manifold 6 is filled with the cooling water as the progress of the work process.

In the process of filling the cooling water discharge manifold 6 with cooling water, a part of the air existing in the cooling water discharge manifold 6 is discharged from the outlet 16a because the fuel cell stack 500 is tilted as described above. Instead, it is left behind in the vicinity of a specific part. The specific portion is the upstream end of the cooling water discharge manifold 6, and more specifically, the end of the cooling water discharge manifold 6 on the positive side in the Y direction and the end on the positive side in the Z direction. is there. That is, the specific portion is the portion on the uppermost side in the vertical direction in the cooling water discharge manifold 6.

The air left behind in the vicinity of the specific portion flows into the pipe 400 from the notch 405 as the water level of the cooling water rises in the cooling water discharge manifold 6, and enters the cooling water discharge manifold 6 from the opening end 408. It flows in and is discharged to the outside of the fuel cell stack 500.

The air left behind in the vicinity of the specific portion flows into the pipe 400 because the pressure at the notch 405 is higher than the pressure at the opening end 408. The cause of such a pressure difference is the pressure loss generated by the flow of the cooling water in the cooling water discharge manifold 6.

After the air left behind in the vicinity of the specific part flows into the cooling water discharge manifold 6, the opening end 408 is discharged to the outside of the fuel cell stack 500 without flowing back in the cooling water discharge manifold 6. This is because it is located near 16a.

In this way, the amount of air left behind in the vicinity of the specific part gradually decreases and eventually disappears. When there is almost no air in the specific portion, the cooling water flows into the pipe 400 from the notch 405, and the inside of the pipe 400 is eventually filled with the cooling water. In this way, most of the air is discharged from the cooling water discharge manifold 6, and the cooling water discharge manifold 6 is filled with the cooling water. If the inside of the cooling water discharge manifold 6 is filled with the cooling water, the fuel cell stack 500 can be operated normally.

The present invention is not limited to the embodiments, examples, and modifications of the present specification, and can be realized by various configurations within a range not deviating from the gist thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the column of the outline of the invention may be used to solve some or all of the above-mentioned problems. , Can be replaced or combined as appropriate to achieve some or all of the above effects. If the technical feature is not described as essential herein, it may be deleted as appropriate. For example, the following is exemplified.

FIG. 5 is a cross-sectional view taken along the line AA in a form in which the pipe 400a is provided instead of the pipe 400 described above. The pipe 400a is a bent pipe unlike the pipe 400. Specifically, the pipe 400a is in contact with the through hole of the insulating plate 270 in the vicinity of the opening end 408. As described above, the opening end 408 of the pipe 400a is also arranged near the outlet 16a as in the above-mentioned pipe 400.

As yet another embodiment, as shown in FIG. 5, the pipe 400a may have an open end 408a instead of the open end 408. The opening end 408a is also arranged near the outlet 16a as in the opening end 408. More specifically, the opening end 408a is located on the minus side in the Y direction with respect to the opening end 408, and is arranged in the flow path of the cooling water pipe 600 connected to the insulating plate 270.

FIG. 6 is a cross-sectional view taken along the line AA when the fuel cell stack 500 including the pipe 400 is mounted in a flat stack. Flat product mounting is a mounting method in which the negative side in the Y direction coincides with the downward direction in the vertical direction. The air discharge function of the pipe 400 is exhibited even in the case of flat stacking. Further, even if the pipe 400a is used, the air discharge function is exhibited in the case of mounting in a flat stack.

As still another form, the following contents are exemplified.

The open end 404 of the pipes 400, 400a does not have to be in contact with the terminal plate.

The vehicle equipped with the fuel cell may be a connected car. A connected car is a car that is equipped with a communication device and can receive services by communicating with the cloud.

The cooling water discharge manifold on which the pipe 400 or the pipe 400a is arranged may be formed as an external manifold. The external manifold is a component integrally molded with resin or the like, and is installed by pressing it against the side surface of the cell laminate. Like the inner manifold, the outer manifold functions as a flow path for supplying and discharging the fuel gas, the oxidant gas, and the cooling water to each cell. When an external manifold is used, each cell is not provided with an opening for forming the manifold.

1 ... Fuel gas supply manifold 2 ... Fuel gas discharge manifold 3 ... Oxidizing agent gas supply manifold 4 ... Oxidizing gas discharge manifold 5 ... Cooling water supply manifold 6 ... Cooling water discharge manifold 11 ... Opening 12 ... Opening 13 ... Opening 14 ... Opening 15 ... Opening 16 ... Opening 16a ... Exit 20a ... Wall 20b ... Wall 20c ... Wall 20d ... Wall 20e ... Wall 20f ... Wall 30 ... Sealing member 30a ... First sealing member 30b ... 2nd seal member 30c ... 3rd seal member 30d ... 4th seal member 30e ... 5th seal member 100a ... Anode side separator 100c ... Catalyst side separator 111 ... Flow path 112 ... Projection 210 ... Power generation compatible part 250 ... Support frame 260 ... Terminal plate 265 ... Terminal plate 270 ... Insulation plate 280 ... MEGA plate 300 ... Cell 300A ... Cell laminate 400 ... Pipe 400a ... Pipe 404 ... Open end 408 ... Open end 408a ... Open end 410 ... Support part 410a ... Support part 500 ... Fuel cell stack 600 ... Cooling water piping

Claims (3)

It ’s a fuel cell stack,
A cell laminate in which multiple cells are laminated, and
A discharge manifold for discharging cooling water from the cell laminate,
A pipe arranged in the discharge manifold and open at both ends , including a pipe for discharging the air existing in the discharge manifold to the outside of the fuel stack .
One end of both ends of the pipe is located near the outlet of the discharge manifold.
The other end of both ends of the pipe is a fuel cell stack located on the upstream side of the discharge manifold with respect to the one end. In the fuel cell stack according to claim 1.
A fuel cell stack having a notch at the other end of the pipe. The fuel cell stack according to claim 1 or 2 further comprises.
With terminal plates arranged at both ends of the cell laminate,
A fuel cell stack in which the other end of the pipe is in contact with the terminal plate.

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