JPH03210772A - Device for cooling and method for flowing refrigerant in fuel cell - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling device for a fuel cell that cools a cell stack by flowing a refrigerant through a cooling plate incorporated in the cell stack of the fuel cell, and the cooling device thereof. This invention relates to a refrigerant flow method.

[Conventional technology]

FIG. 5 shows a general cell stack (also called cell stack) structure of a fuel cell equipped with a cooling plate.

In the figure, 1 is a matrix layer 11i holding an electrolyte.
Fuel electrode 12. Oxidizer electrode 13. Electrode base material with lip 14゜1
5 and a separator 16, and a cell stack 2 is constructed by stacking a large number of such single cells 1. Furthermore, water-cooled cooling plates 3 are interposed in the cell stack 2 every few cells. This cooling plate 3 is the electrode base material 14, 15 with lips described above.
It is an assembly of a cooling plate 3 made of carbon having a coefficient of thermal expansion substantially equal to that of the separator 16, and a cooling pipe 5 made of metal buried inside the cooling plate 3 and arranged in parallel.
Each cooling pipe 5 is connected to the header vibro and then to an external refrigerant supply pipe (not shown). FIG. 6 is a plan view of the cooling plate 3 forming the cooling structure, and the cooling water of the refrigerant supplied from the refrigerant inlet pipe 21 flows through the header 6 on the inlet side, the cooling pipe 5 in the direction of the arrow, and then flows into the header on the outlet side. 6 to the refrigerant outlet pipe 22. FIG. 7 is a side view showing how the cooling plates 3 are stacked alternately with a plurality of cell stacks 2, and cooling water is supplied from the refrigerant inlet pipes 21 in parallel and in the same direction. arrow 2
3 and reaches the refrigerant outlet pipe 22, from where it is cooled by a cooling heat exchanger (not shown), circulates, and returns to the refrigerant inlet pipe 21. Note that 31 is a current collector plate that takes out the electricity generated from the cell stack 2;
2 is an electrically insulating plate, and 33 is a tightening plate that tightens the stacked structure of the cell stack 2 and the cooling plate 3.

[Problem that the invention aims to solve]

In such a conventional cooling structure, as shown in FIG. 6, the cooling water supplied from the refrigerant inlet pipe 21 is initially kept at a sufficiently low temperature, but when it reaches the cooling pipe 5 in the cooling plate 3, The temperature gradually rises as the cell stack disposed adjacent to the cooling plate 3 receives the heat generated by its power generation action, and the cooling water that has cooled down sufficiently around zone 35 reaches the zone 36. It will be quite expensive.

Accordingly, in the cell stack, the temperature of the portion in contact with the zone 35 on the same stacked surface is low, and the temperature of the portion in contact with the zone 36 is high. Therefore, even in the same cell stack, the reaction temperature related to power generation is not uniform and varies depending on the location, and the upper limit of the temperature most suitable for power generation is determined at the part that contacts zone 36, and the upper limit of the temperature that is most suitable for power generation is determined at the part that contacts zone 35, which has a lower temperature. In this case, power generation must be performed at a low temperature that is not suitable for power generation, and the problem arises that the cell stack as a whole cannot fully demonstrate its power generation performance.

The present invention has been made in view of this point, and it is an object of the present invention to provide a cooling device for a fuel cell and a coolant flow method therefor, which can uniformize the temperature in each part of a cell stack and exhibit sufficient generation performance.

(Means for solving !Ill) In order to solve the above problems, as a cooling device for a fuel cell according to the present invention, a cooling plate installed in a battery stack formed of a plurality of plate-shaped unit cells is provided. In a fuel cell cooling device in which the cell stack is cooled by passing a refrigerant through the cooling pipe from the refrigerant pipe through the header, the refrigerant pipe is connected to the cooling pipe in the cooling plate through the header. Two sets of coolant are used in which the flow directions are opposite to each other.Furthermore, as a coolant flow method in this cooling device, cooling pipes in a cooling plate interposed in a battery stack formed of a plurality of plate-shaped unit cells are used. The refrigerant flow reservoir connects the refrigerant pipes 2 & Il in opposite directions through the header, and the flow direction of the refrigerant supplied to the refrigerant pipes is reversed at regular intervals.

[Effect]

According to this invention, in a cooling device for a fuel cell, two sets of refrigerant pipes are provided, one for an inlet and one for an outlet, for supplying refrigerant to a cooling pipe embedded in a cooling plate installed in a cell stack. Since the flow directions of the refrigerant supplied to the two sets of refrigerant piping are opposite to each other, distribution is possible using these two sets of refrigerant piping! If refrigerant is supplied to every other cooling plate, every other cell stack to be cooled will be cooled by the cooled refrigerant from the opposite direction, so that the temperature of the cell stack can be cooled almost uniformly. In addition, the refrigerant flow method in this cooling device is such that the flow direction of the refrigerant is reversed at regular intervals, so the cell stack is prevented from being locally overheated or kept at a low temperature for a long time. Temperature can be made uniform.

【Example〕

The present invention will be explained below based on examples. FIG. 1 is a plan view showing a cooling device for a fuel cell, which is an embodiment of the present invention, and FIG. 2 is a side view thereof.

Here, an example is shown in which a plurality of cooling plates 3 and cell stacks 2 are alternately stacked. In this example, two sets of refrigerant pipes 2 are shown.
4.25 and 26.27 are arranged, and the cooling plate 3 arranged at the top has its cooling pipe 5 connected to the cooling pipe 26.27 via the header 7, and is used as a refrigerant. Cooling water is supplied from the cooling pipe 26, flows in the direction shown by the refrigerant direction arrow 28, enters the cooling pipe 5 via the header 7 on the inlet side, and flows back into the coolant via the header 7 on the outlet side. The cooling plate located second from the top to the cooling pipe 27 receives cooling water from the refrigerant pipe 24, and passes through the header 8 on the inlet side to the uppermost part indicated by the refrigerant direction arrow 29. The refrigerant flows through the cooling pipe 5 in a direction opposite to the flow direction in the cooling plate disposed in the cooling plate, and reaches the refrigerant pipe 25 again via the header 8 on the outlet side. The third cooling plate from the top is connected to the same refrigerant pipe 26゜27 as the top cooling plate, and the cooling water is passed in the same direction as that of the cooling plate placed at the top. The cooling plate disposed at is connected to the refrigerant pipes 24 and 25 disposed second from the top, and similarly flows cooling water in the same flow direction. As described above, the structure is such that the direction of flow of cooling water is alternately opposite to each other one by one across the stacked cell stacks 2. Therefore, since the cell stack 2 is cooled by the cooling water in two opposing directions on its upper and lower surfaces, the temperature can be made more uniform over the entire surface of the cell stack, compared to conventional cooling in one direction.

Next, the method of circulating the refrigerant will be explained with reference to the system diagram in FIG. 3 and the time chart in FIG. 4. In FIGS. 1 and 2, the cooling water supplied to the cooling pipes 5 in the plurality of cooling plates 3 is supplied from two sets of refrigerant pipes 24.25 and 26.27 arranged alternately. In this way, the plurality of cooling plates are divided into a group that is supplied with cooling water from the refrigerant piping 26.27 via the header 7, and a group that is supplied with cooling water from the refrigerant piping 24.25 via the header 8. to 2
valves 41, 42, 43 . shown in FIG. 3, respectively.
44, 45, 46, 47, 48 are arranged in the cooling water flow path, and the cooling water supplied from the refrigerant supply system is passed through the valves 41, 42.
45, 46 to the cooling pipe 5, valves 43, 44
, 47, 48, the return cooling water is returned from the cooling pipe 5 to the refrigerant discharge system.

Then, as shown in the time chart of FIG. 4, the valve 41.
42.43, 44.45.46.47.48 open at regular intervals.

When the closing control is performed, the flow direction of the cooling water flowing through the cooling pipe 5 in the cooling plate 3 is reversed at regular intervals, and until now the temperature in the cooling plate was rising near the outlet of the cooling water. By reversing the flow direction of the cooling water, the location changes to a location near the inlet where cold cooling water comes in, making it possible to eliminate local temperature fluctuations.

〔Effect of the invention〕

As described above, this invention is a cooling device for a fuel cell, by dividing the cooling system through which the cooling pipes in the cooler flow through into two groups, and supplying refrigerant to alternately arranged cooling plates from opposite directions. The refrigerant flow method is to reverse the flow direction of the refrigerant on all cooling plates at regular intervals to cool the cell stacks located adjacent to the cooling plates so that the temperature during operation is almost uniform. As a result, the cell stack will not be locally overheated or too cold, and will be able to efficiently demonstrate its full power generation performance.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an embodiment of a cooling device for a fuel cell according to the present invention, FIG. 2 is a side view of a cell stack having a cooling device according to the present invention, and FIG. 3 is a coolant according to the present invention. A system diagram of the refrigerant that realizes the flow method, FIG. 4 is a time chart explaining the flow method of the refrigerant system diagram shown in FIG. 3, and FIG. 5 is a perspective view of a battery stack with a conventional cooling device. , FIG. 6 is a plan view of a cooling plate with a conventional cooling device, and FIG. 7 is a side view of a battery stack with a conventional cooling device. 1: Single battery (single cell), 2: Battery stack (cell stack) 3: Cooling plate, 5: Cooling pipe, 7° 8: Header 24.25.26.27: Refrigerant piping, 28° 29
: Refrigerant flow direction, 31: Current collector plate, 32: Electrical insulating plate,
33: Tightening plate, 41, 42, 43. 44. 45, 46.
47.48: Valve. Figure 1 Figure 1 Figure 1

Claims (1)

[Scope of Claims] 1) A method of causing a refrigerant to flow through a cooling pipe in a cooling plate interposed in a battery stack formed of a plurality of plate-shaped unit cells through a header from a refrigerant pipe to stack the battery stack. A fuel cell cooling device for cooling a fuel cell, characterized in that two sets of refrigerant pipes connected to cooling pipes in a cooling plate via a header are arranged in opposite directions of refrigerant flow. cooling system. 2) Two sets of refrigerant pipes with refrigerant flow directions in opposite directions are connected to the cooling pipes in the cooling plate interposed in the battery stack formed by a plurality of plate-shaped unit cells via headers. connection,
A refrigerant flow method for a fuel cell, characterized in that the flow direction of the refrigerant supplied to the refrigerant pipe is reversed at regular intervals.