JPS6322418B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cooling device for a fuel cell.
In particular, it is an object of the present invention to improve the cooling effect of a cooling plate having a cooling gas passage and to simplify the assembly configuration of the cooling plate.

Since the temperature of a phosphoric acid fuel cell rises to over 200°C due to the heat of reaction, cooling is required to maintain the operating temperature at around 180°C.

One cooling method uses part of the air supplied to the battery as reaction air and the other part (approximately 75% of the amount of air introduced) as cooling air, and the other uses separate cooling of each reaction gas (air and hydrogen). There is a method of supplying dedicated gas. In either case, the battery stack includes a stack of unit cells and gas separation plates, with cooling plates having cooling gas passages inserted every few cells.

In general, the carbonaceous cooling plate 1 is divided into upper and lower halves, as shown in FIG. 1, and recesses 2', 2' which join together to form the cooling gas passage 2 are formed at the joint surface C thereof. These divided cooling plates 1', 1' are formed by hot pressing a mixed powder of graphite and a binder and then carbonizing the binder by high temperature treatment. Then, when joining the divided cooling plates 1', 1', their joint surfaces are adhered with a mixture of graphite and binder made into a paint form using a solvent, and heat treatment is performed again to carbonize the binder in the same manner as described above.

As described above, since the cooling plate is made of carbonaceous material, there are problems in that the cooling effect is not sufficient and the manufacturing process is complicated.

In the present invention, a strip made of a material with good thermal conductivity is closely attached to both side walls of the cooling gas passage of a carbonaceous cooling plate, and at least one end of the strip is provided with a gap between the stack surface and the stack in the stacking direction. The cooling effect is improved by providing a protruding fin portion. The strip having the fins needs to have not only good thermal conductivity but also heat resistance and acid resistance, and for example, an alumite-treated aluminum plate or a stainless steel plate is suitable.

Further, in the present invention, the strip having the fin portion is also used as a connecting member for the divided cooling plates, thereby simplifying assembly.

The embodiment will be described below with reference to the figures, and the same reference numerals as in FIG. 1 are used for the corresponding parts.

1 and 2 both show the slopes of a battery stack, with FIG. 1 showing a case equipped with a conventional cooling plate and FIG. 2 showing a case equipped with a cooling plate of the present invention.

The battery stack 3 has unit cells 4 and carbonaceous gas separation plates 7 having reaction gas supply grooves 5 and 6 stacked alternately, and a carbonaceous cooling plate 1 having the cooling gas passages 2 for every few cells. mediated and composed.

The cooling plate 1 is divided into upper and lower halves like the conventional product, and when they are joined, a third
The divided cooling plates 1',
It is clamped at 1'. In this case, the fin portion 8 protruding from the battery stack 3 extends in the stacking direction with a flow gap S without contacting the stack surface.

In order to use this strip 9 as a connecting member for the divided cooling plates 1', 1', as shown in FIG.
Fixing grooves 10, 10 are cut along both sides of 2', and strip pieces 9, 9 are press-fitted into the opposing grooves, respectively, to connect the divided cooling plates 1', 1'. At this time, the spacing between opposing grooves and the width of the strip 9 are selected so that the joint surfaces C of the divided cooling plates are in close contact with each other.

In the rectangular stack 3 of the above embodiment, a manifold for each reactant gas (not shown) is provided on one of the opposite sides.
are arranged side by side, hydrogen gas is sent from the supply groove 5 along the path indicated by the dotted line arrow, and air is sent from the supply groove 6 through the path shown by the solid line arrow to the corresponding electrode of each unit cell 4, respectively, to participate in the battery reaction. A cooling gas manifold (not shown) is attached to the other opposing side surface, and a cooling gas such as air, hydrogen, or helium is sent to the cooling gas passage 2 to cool the stack 3.

Since both side walls of these gas passages 2 are made of strips 9 made of an alumite treated aluminum material which has better thermal conductivity than carbon material, the cooling effect is improved. Also, since the strip has fins 8 extending outside the stack at both ends, the surface that comes into contact with the cooling gas is significantly increased, thereby improving the cooling performance. Therefore, since the flow rate of the cooling gas can also be reduced, the power consumption of the blower can be reduced and the power generation efficiency of the battery can also be improved.

FIG. 6 shows the case of hexagonal stack 3,
In this case a manifold (not shown) on each opposite side.
It is sufficient to form each reaction gas path and cooling gas path by attaching the following. In this case as well, the H-shaped strip can be incorporated into the cooling gas passage in the same manner as described above.

As described above, according to the present invention, the cooling gas passage of the carbonaceous cooling plate interposed in the battery stack has both side walls made of a member with good thermal conductivity, and outside the gas passage there is a fin portion extending from the said member. Because it has
The cooling effect is extremely good, and the power consumption of the blower is also reduced by reducing the amount of cooling gas blown.

In addition, the above-mentioned member can also be used as a joining member for divided cooling plates, and the joining of divided plates can be performed mechanically and extremely easily, eliminating complicated processes such as carbonization treatment that are required when using conventional adhesives. It has excellent features such as eliminating the need for

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional battery stack.
FIG. 2 is a perspective view of a battery stack according to the present invention, FIG. 3 is a schematic side view of the same stack as above, FIG. 4 is a perspective view of an H-shaped strip according to the present invention, and FIG. An enlarged slope view of the main part of the cooling plate in the case of
FIG. 6 is a plan view of a hexagonal stack. 1...Cooling plate, 1', 1'...Divided cooling plate, 2...Cooling gas passage, 2', 2'...Opposed recess, 3...Battery stack, 4...Unit cell, 5, 6...Each reaction gas supply groove ,
7...Gas separation plate, 8...Fin portion, 9...Strip piece, 1
0...kerf.

Claims (1)

[Scope of Claims] 1. A cooling plate having a cooling gas passage interposed in a stack of unit cells and gas separation plates constituting a battery stack, wherein the cooling gas passage has a heat conductive layer on both side walls. Cooling of a fuel cell, characterized in that strips having good properties are brought into close contact with each other, and at least one end of the strip is provided with a protruding fin portion that extends in the stack stacking direction with a flow gap between the side surface of the stack and the stack. Board. 2. The cooling plate is composed of two plates having opposing recesses that form the gas passages when joined, and the strip piece is press-fitted into opposing grooves formed along both sides of each recess. 2. A cooling plate for a fuel cell according to claim 1, characterized in that the cooling plate comprises two plates joined together.