JPH06124716A - Cooling plate for fuel cell - Google Patents

Abstract

PURPOSE:To provide a fuel cell cooling plate for maintaining uniform temperature distribution over the cross sectional plane of a cell stacked body at the time of removing heat occurring during fuel cell power generation via a cooling medium flowing through a cooling tube laid on the plate. CONSTITUTION:A cooling tube 20 running along the intermediate section of the cooling substrate 10 of a cooling plate 9, is fitted with an inside inlet header pipe 23 at one end, and an inside outlet header pipe 24 at the other end. Also, a cooling tube 22 running along the periphery of the substrate 10 from an intermediate section to an opposite side, is fitted with an outside inlet header pipe 25 at one end and an outside outlet header pipe 26 at the other end. In this case, the temperature of a cooling medium flowing from the pipe 23 to the cooling tube 20 is kept lower than the temperature of the medium coming from the pipe 25.

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 the cooling plate of the fuel cell including the cooling pipe and the cooling substrate in which the cooling pipe is embedded along the plate surface, the cooling pipes are sequentially grouped from the central portion of the cooling plate toward the peripheral portion,
A plurality of cooling systems having each group as a cooling system are provided, and the temperature of the cooling medium flowing into each cooling system is set to be higher in the cooling system from the central portion to the peripheral portion.

Further, in the above cooling plate, the cooling pipes are embedded in parallel along the opposite side faces of the cooling substrate, and the cooling system is such that the cooling pipes are sequentially arranged from the central portion of the cooling substrate toward the opposite side faces. The cooling pipes are divided into groups, and the cooling pipes that are opposed to each other with the cooling pipe passing through the central portion sandwiched therebetween are formed in the same group.

[0011]

[Function] The cooling plate is a battery stack formed by stacking single cells,
It is inserted every time a plurality of cells are stacked,
The cooling medium is passed through a cooling pipe embedded along the plate surface of the cooling plate of the cooling plate to remove heat generated during power generation of the fuel cell. Divide into groups and provide multiple cooling systems with each group as a cooling system. In this case, the plurality of cooling systems, a plurality of cooling pipes are embedded in parallel along the facing side surface of the cooling substrate, the embedded cooling pipes are sequentially grouped from the central portion toward the facing side surface, In addition, the cooling pipes that are opposed to each other with the cooling pipe passing through the central portion interposed therebetween are set as the same group, and each group is configured as a cooling system. By increasing the temperature of the cooling medium flowing into each cooling system from the central part to the peripheral part, the heat dissipation from the peripheral part of the cell stack during power generation of the fuel cell leads to the central part to the peripheral part. For a battery stack having a lower temperature, heat is removed from the central part having a higher temperature and the peripheral part having a lower temperature so that the temperature becomes uniform, and the temperature distribution of the battery stack is made uniform.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 is a plan view of a cooling plate of a fuel cell according to an embodiment of the present invention, and FIG. 2 is a side view of FIG. Note that FIG.
In FIG. 2, the same parts as those in the conventional example of FIG. 4 are designated by the same reference numerals, and the description thereof will be omitted. 1 and 2, the cooling substrate 10 has a plurality of cooling pipes 20 arranged in parallel through the central portion thereof.
In parallel with the cooling pipe 20, a plurality of parallel cooling pipes 22 are embedded in the peripheral region from the central portion of the cooling substrate 10 to the opposing side surface 21. The inner inlet header pipe 23 is attached to one pipe end on both sides of the cooling pipe 20 passing through the central portion projecting from the cooling substrate 10, and the inner outlet header pipe 24 is attached to the other pipe end. Reference numeral 23 is connected to an inner cooling water supply system (not shown), and inner outlet header pipe 24 is connected to an inner cooling water discharge system.

On the other hand, an outer inlet header pipe 25 is attached to one pipe end on both sides of the cooling pipe 22 which passes through the peripheral region projecting from the cooling substrate 10, and an outer outlet header pipe 26 is attached to the other pipe end. The outer inlet header pipe 25 is connected to an outer cooling water supply system (not shown), and the outer outlet header pipe 26 is connected to an outer cooling water discharge system (not shown).

Here, the temperature of the cooling water flowing through the cooling pipe 22 passing through the peripheral region is about 5 to 10 ° C. higher than that of the cooling water flowing through the cooling pipe 20 passing through the central portion. The temperature difference is obtained as follows. Each of the outer and inner cooling water supply systems is provided with a heater to change the supply heat amount to give the temperature difference, or one of the cooling water supply systems is provided with a heat exchanger, and the heat is exchanged by the heat exchanger. Give a temperature difference.

With such a configuration, the cooling pipe 22 passing through the peripheral region of the cooling substrate 10 is provided in the cooling pipe 20 passing through the central portion.
Since the cooling water having a temperature higher than the temperature of the cooling water flowing from the inner inlet header pipe 23 flows into the outer inlet header pipe 25, the central portion of the cell stack 8 is well cooled during power generation of the fuel cell, and the peripheral region Has a reduced cooling effect, so that the temperature distribution of the operating temperature on the sectional plane of the battery stack 8 is made uniform.

In this embodiment, the cooling pipes embedded in the cooling substrate 10 have two cooling systems, but three or more cooling systems may be used. In this case, the temperature distribution of the battery stack 8 is more uniform. To be done.

[0017]

As is apparent from the above description, according to the present invention, with the above-mentioned structure, the heat generated during the power generation of the fuel cell is generated by the cooling medium whose temperature is higher from the central portion to the peripheral portion of the cell stack. Since the heat is removed via the cooling plate, the temperature distribution of the operating temperature of the cell stack becomes uniform, and as a result, the power generation characteristics of the fuel cell are improved and stable long-term operation can be performed.

[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]

 1 Single Battery 8 Battery Stack 9 Cooling Plate 20 Cooling Pipe 22 Cooling 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 pipe is embedded along the plate surface. In a cooling plate for a fuel cell including a cooling substrate, the cooling pipes are sequentially grouped from a central portion of the cooling substrate toward a peripheral portion,
A cooling plate for a fuel cell, wherein a plurality of cooling systems each having a cooling system are provided, and a temperature of a cooling medium flowing into each cooling system is set higher in a cooling system from a central portion to a peripheral portion. 2. The cooling pipe according to claim 1, wherein the cooling pipes are embedded in parallel along opposite side surfaces of the cooling substrate, and the cooling system extends from the central portion of the cooling substrate to the opposite side faces. A cooling plate for a fuel cell, characterized in that the cooling pipes are sequentially divided into groups, and the cooling pipes that are opposed to each other with a cooling pipe passing through the central portion therebetween are formed into the same group.