JPH06231774A - Cooling plate of fuel cell - Google Patents

Abstract

PURPOSE:To make the temperature distribution on the plane of the cross section of a battery accumulated body uniform when the heat generated at the time of power generation of a fuel cell is cooled by a cooling medium flowing in a cooling pipe provided on a cooling plate. CONSTITUTION:Each pipe end group, for which a cooling pipe 20, which is bifurcated from an inlet header pipe 23, and which passes the center part of a cooling base plate 10, is divided into two parts, and intermediate header pipes 29, 30 connected to the pipe end group of cooling pipes 21, 22 passing the peripheral part, respectively, are provided. Outlet header pipes 25, 26 are provided on the other pipe end parts of the cooling pipes 21, 22. A cooling medium, the cooling ability of which is degraded because of temperature rise caused by the cooling medium flowing in the cooling pipe 20 in the center part, is flowed into the cooling pipes 21, 22 on the peripheral part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling pipe which is provided for each unit cell stacked in a battery stack formed by stacking the unit cells and through which a cooling medium for cooling the battery stack flows. And a cooling plate for a fuel cell having

[0002]

2. Description of the Related Art A cell stack of a fuel cell is formed by stacking a plurality of single cells and inserting a cooling plate for each of the stacked single cells. The cooling plate includes a cooling pipe through which a cooling medium for cooling the battery stack flows, and a cooling substrate in which the cooling pipe is embedded. The related art will be described below with reference to the drawings.

FIG. 3 is an exploded perspective view of a battery stack having a conventional cooling plate. In FIG. 3, the unit cell 1 has a rectangular shape, a matrix layer 2 holding an electrolyte, a fuel electrode 3 and an oxidant electrode 4 sandwiching the matrix layer 2, a fuel electrode 3, and an oxidant electrode 4
It is composed of ribbed electrode base materials 5 and 6, which respectively hold and, and a separator 7. Battery stack 8 is a single cell 1
Is formed, and a cooling plate 9 is formed every time a plurality of unit cells 1 are stacked.

As shown in FIG. 4 and FIG. 5, which is a side view of FIG. 4, the cooling plate 9 has a carbon cooling substrate 10 having substantially the same thermal expansion coefficient as the ribbed electrode substrates 5 and 6 and the separator 7 made of carbon. A cooling pipe 11 through which cooling water as a metallic cooling medium flows evenly and in parallel along side surfaces of the cooling substrate 10 facing each other in a plate, and a cooling pipe protruding from the cooling substrate 10. It is composed of an inlet header pipe 12 and an outlet header pipe 13 which are respectively connected to the pipe ends on both sides of 11. The inlet header pipe 12 is connected to a cooling water supply system (not shown), while the outlet header pipe 13 is connected to a cooling water discharge system (not shown).

Here, as a method of embedding the cooling pipes 11 in parallel in the cooling substrate 10, the cooling pipes 11 are provided in a plurality of rows of cooling pipe-shaped grooves formed on the mating surfaces of the cooling substrate 10 having a vertically divided structure. Or a groove capable of accommodating a plurality of U-shaped cooling pipes is formed on the surface of one cooling substrate 10, and each cooling pipe 11 is accommodated in this groove, and then the same carbon is used. The method of covering with a lid made of is adopted.

With such a structure, fuel gas is supplied to the fuel electrode 3 of the unit cell 1 constituting the cell stack 8 through the ribbed electrode base material 5, while the ribbed electrode base material 6 is attached to the oxidizer electrode 4. By supplying air through the cells, each cell 1 causes a cell reaction, and the fuel cell generates electricity. By the way, heat generated during power generation of the fuel cell is generated by cooling water from a cooling water supply system (not shown), each inlet header pipe 12, and the cooling pipe 11 of each cooling plate 9.
To remove the heat and maintain the operating temperature of the fuel cell. In this case, the temperature of the cooling water flowing into the cooling pipe 11 is about 160 ° C. in the case of the phosphoric acid fuel cell.
The heat generated during power generation is removed by boiling cooling of the cooling water flowing through. Then, the cooling water that has removed heat and is discharged from the cooling pipe 11 is collected in each outlet header pipe 13 and is discharged to the outside through a cooling water discharging system (not shown).

[0007]

A cooling plate 9 for removing heat generated during power generation of a fuel cell is a cooling pipe 1 through which cooling water flows.
1 is uniformly embedded in the cooling substrate 10, and there is no difference in thermal conductivity between the central portion and the peripheral portion of the rectangular cooling substrate 10. However, since the heat generated during power generation is dissipated from the peripheral portion 16 shown in FIG. 6, the temperature of the peripheral portion 16 is lower than that of the central portion 15, and the temperature distribution on the cross-sectional plane of the battery stack 8 is rectangular. Has a temperature distribution in which the center is highest and the temperature decreases toward the periphery.

With such a temperature distribution, when the fuel cell is in operation, power is generated in the peripheral portion of the cell stack at a temperature lower than that in the central portion, so it is designed to generate power at a uniform temperature.
There is a drawback in that the manufactured battery laminate cannot sufficiently exhibit its performance. An object of the present invention is to provide a cooling plate for a fuel cell, which makes uniform the temperature distribution of the cell stack when the heat generated during power generation of the fuel cell is removed by a cooling medium.

[0009]

In order to solve the above problems, according to the present invention, a plurality of cells are stacked in a battery stack formed by stacking the cells, and a cooling medium flows through the cells. In a cooling plate of a fuel cell including a cooling pipe for cooling and a cooling substrate embedded in parallel along the opposite side faces, the cooling pipe extends from the central portion of the cooling substrate to each of the opposite side faces. Are sequentially divided into cooling pipe groups, and one pipe end group of the first cooling pipe group at the center is used as the inlet of the cooling medium, and the other pipe end group or each pipe end group obtained by dividing the pipe end group into two. The pipe end groups of the second cooling pipe groups on both sides adjacent to this are respectively connected by the first header pipes, and the other pipe end groups of the second cooling pipe groups on both sides are connected to this pipe end group. Connect the pipe end groups of the third cooling pipe groups on both sides adjacent to each other with the second header pipes. And sequentially connecting the pipe ends of the cooling pipe group with the header pipe, and forming the cooling plate by using the pipe end group facing the header pipe of the cooling pipe group facing the opposite side surfaces of the cooling substrate as the outlet of the cooling medium. And

The cooling pipe group provided on the cooling plate includes a first cooling pipe group at the center of the cooling substrate and second cooling pipes on both sides adjacent to the first cooling pipe group and facing opposite side surfaces of the cooling substrate. It shall consist of a group.

[0011]

The cooling pipes in which the cooling mediums embedded in parallel in the cooling substrate along the opposite side faces of the substrate flow therethrough are sequentially grouped into cooling pipe groups from the central portion of the cooling substrate toward the opposite side faces. To do. Then, one pipe end group of the first cooling pipe group in the central portion is used as an inlet of the cooling medium, and the other pipe end group or each pipe end group obtained by dividing this into two is adjacent to the first cooling pipe group. It connects with each of the pipe end groups of the second cooling pipe group on both sides by the first header pipe, and further connects with the other pipe end group of the second cooling pipe group on both sides and on both sides adjacent to this cooling pipe group. Each of the pipe end groups of the third cooling pipe group is connected by the second header pipe, and thus the cooling pipe groups are sequentially connected by the header pipe, and the cooling pipes on both sides facing the opposite side surfaces of the cooling substrate. By providing the cooling plate having the pipe end group facing the header pipe of the group as the outlet of the cooling medium, the cooling medium flowing into the first cooling pipe group at the central portion is adjacent to the first cooling pipe group. It flows through the cooling pipe groups such as the second cooling pipe group and the third cooling pipe group on both sides in order.

Therefore, by interposing the above-mentioned cooling plate between the unit cells of the cell stack, the first cooling pipe group located at the center of the cooling substrate located at the center of the cell stack during power generation of the fuel cell. The temperature of the cooling medium flowing therethrough rises, the temperature of the heated cooling medium flows to the second cooling pipe group via the first header pipe, and the temperature of the cooling medium further rises. Flow through the tube group. For this reason, the cooling capacity of the cooling medium decreases from the central part of the battery stack toward the lower temperature peripheral part, and prevents the temperature of the peripheral part which becomes low due to the dissipation of heat to the outside from becoming unnecessarily low. The temperature distribution of the entire laminated body is made uniform.

The cooling pipe groups provided on the cooling plate are a first cooling pipe group in the central portion of the cooling substrate, and a second cooling pipe group on both sides facing the opposite side surfaces of the cooling substrate adjacent thereto. Even if it is configured as above, the temperature distribution of the entire battery stack is made substantially uniform as described above.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view of a cooling plate according to an embodiment of the present invention, and FIG. 2 is a side view of FIG. In FIGS. 1 and 2, the cooling substrate 10 is arranged in parallel along the opposite side surfaces of the cooling substrate 10 and passes through the central portion, and the cooling pipes 2 pass through the peripheral portions on both sides.
1 and 22 are embedded, and both ends thereof project from the side surface of the cooling substrate 10. Here, an inlet header pipe 23 is attached to one pipe end of the cooling pipe 20 passing through the central portion of the cooling substrate 10, and an inlet pipe 24 for a cooling medium is attached to the inlet header pipe 23.

Further, the cooling pipes 21 and 22 passing through the peripheral portions on both sides of the cooling substrate 10 are provided with outlet header pipes 25 and 26 at respective pipe end portions along with the inlet header pipe 23, and further, the outlet header pipe 25. , 26 are provided with outlet pipes 27, 28 for the cooling medium, respectively. The other pipe ends of the cooling pipes 21 and 22 attached to the outlet header pipes 25 and 26, respectively, and the inlet header pipe 23.
One cooling pipe 20 obtained by dividing the cooling pipe 20 attached to the
The intermediate header pipe 29 is connected to the pipe end of the cooling pipe 20 and the intermediate header pipe 30 is connected to the pipe end of the other cooling pipe 20.

With such a structure, the cooling medium flowing from the inlet pipe 24 flows from the inlet header pipe 23 through the cooling pipe 20, cools the central portion of the battery stack contacting the cooling pipe 20, and raises the temperature from itself. It flows into the intermediate header pipes 29 and 30. Then, it flows from the intermediate header pipes 29 and 30 to the cooling pipes 21 and 22 in the peripheral portions to cool the peripheral portions, further raises the temperature, and is collected in the outlet header pipes 25 and 26, respectively, and externally from the outlet pipes 27 and 28. Is discharged to.

Due to such cooling of the cooling medium, the central portion of the cell stack is well cooled during power generation of the fuel cell, while the cooling effect is reduced in the peripheral portion, so that the operating temperature on the cross section plane of the cell stack is reduced. The temperature distribution is almost uniform. Although two intermediate header pipes 29 and 30 are provided in the present embodiment, the same effect can be obtained by connecting them to one intermediate header pipe.

In this embodiment, the cooling medium is the cooling pipe 20.
From the cooling pipe group consisting of the cooling pipes 2 on both sides adjacent to this
Although it is made to flow to the cooling pipe group consisting of 1, 22,
The number of cooling tube groups may be increased so that the cooling medium sequentially flows through these cooling tube groups, in which case the temperature distribution of the battery stack is made more uniform.

[0019]

As is apparent from the above description, according to the present invention, the heat generated during the power generation of the fuel cell according to the present invention flows from the central portion of the cooling plate to the peripheral portion in order and from the central portion to the peripheral portion. Heat is removed by the cooling medium whose temperature rises toward the end and the cooling capacity has decreased, so the temperature distribution of the operating temperature of the cell stack is made uniform, and the power generation characteristics of the fuel cell are improved and stable long-term operation is achieved. Can be done.

[Brief description of drawings]

FIG. 1 is a plan view of a cooling plate of a fuel cell according to an embodiment of the present invention.

FIG. 2 is a side view of a cooling plate of the fuel cell of FIG.

FIG. 3 is an exploded perspective view of a cell stack of a fuel cell.

FIG. 4 is a plan view of a conventional cooling plate for a fuel cell.

5 is a side view of the cooling plate of the fuel cell of FIG.

FIG. 6 is a plan view of a cell stack of a fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Single cell 8 Battery laminated body 9 Cooling plate 10 Cooling substrate 20 Cooling pipe 21 Cooling pipe 22 Cooling pipe 24 Inlet pipe 27 Outlet pipe 28 Outlet pipe 29 Intermediate header pipe 30 Intermediate header pipe

Claims (2)

[Claims] 1. A cooling pipe, which is provided for each unit cell stacked in a battery stack formed by stacking the unit cells and through which a cooling medium flows, and the cooling pipes are arranged in parallel along opposite side surfaces. In a cooling plate of a fuel cell including a cooling substrate embedded in the cooling substrate, cooling pipes are sequentially grouped into cooling pipe groups from the central portion of the cooling substrate toward each side surface facing each other, and the first cooling pipe group in the central portion is provided. One pipe end group of the cooling pipe group is used as an inlet of the cooling medium, and the other pipe end group or each pipe end group obtained by dividing the pipe end group into two and the pipe end groups of the second cooling pipe groups on both sides adjacent to the pipe end group. Are respectively connected by a first header pipe, and the other pipe end group of the second cooling pipe group on both sides and the pipe end group of the third cooling pipe group on both sides adjacent to this pipe end group are respectively connected to the first pipe. 2 header pipes, and in this way the pipe ends of the cooling pipe group are sequentially connected by header pipes, Opposing cooling plates of a fuel cell of the pipe end group opposing the header pipe of the cooling tube bank facing side, characterized in that the outlet of the cooling medium. 2. The cooling pipe group provided on the cooling plate according to claim 1, wherein the cooling pipe group is provided in a central portion of the cooling substrate, and adjacent to the first cooling pipe group. And a second cooling tube group on both sides of the cooling plate for a fuel cell.