JPH0465501B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling device for a fuel cell.

[Prior Art] Fuel cells generate electricity through a chemical reaction that generates heat, so it is extremely important to control the reaction, that is, to appropriately control the heat generated, in order to generate electricity in a stable and continuous manner. be.

In order to regulate this generated heat, a cooling tube is embedded in a cooling tube holding plate made of a conductive material, and a cooling device equipped with a heat exchanger that circulates a cooling medium within this cooling tube is inserted into an appropriate location of the stacked battery. The technology is widely used.

Water is often used as a cooling medium due to economic efficiency and stability, but such cooling devices have the following problems.

The electricity generated by the battery can pass through the cooling water and cause a short circuit, so to prevent this, it is necessary to insulate the cooling pipes. However, as the cooling pipes were insulated,
There are problems such as difficulty in sufficiently exchanging heat between the battery and the cooling water. It is extremely important from the original mission of the cooling device that this heat exchange is difficult to be performed sufficiently.

In order to solve the above problem, JP-A-58-
There are techniques disclosed in Japanese Patent No. 16663 and the specification of Japanese Utility Model Application No. 193736/1983. This disclosed technology involves putting a filler made of powder such as graphite and a thermosetting resin between the cooling pipe and the cooling pipe holding plate, and heating and pressurizing it to solidify it. There is technology. A technique has also been disclosed in which a mixture of thermally conductive grease and powder such as graphite is filled between the cooling tube and the cooling tube holding plate.

In the technique using a filler made of powder such as graphite and a thermosetting resin, the final form of the filler is a molding material, and the shrinkage force when this molding material hardens is used to It is placed in close contact with the cooling pipe to obtain good thermal conductivity. Also, in the technology using thermally conductive grease, etc., good thermal conductivity can be obtained using the thermally conductive grease, similar to the above technology.

[Problems to be Solved by the Invention] However, even if the thermal conductivity between the cooling pipe and the cooling pipe holding plate is made good, the expansion and contraction of the cooling pipe that occurs due to heat generation and the vibration that occurs when cooling water starts flowing in will still occur. arise.

On the other hand, with the technology using thermosetting resins, etc., the solid filler is in close contact with the cooling pipe, so although it does have good thermal conductivity, It is not possible to absorb the stress and prevent damage to the cooling pipes, in particular, destruction of the insulation of the cooling pipes. Also, it seems that this stress can be absorbed by using thermally conductive grease etc. as a filler, but since thermally conductive grease etc. is filled in a closed space, this stress is simply transferred to other materials. It only propagates to parts,
Stress will be exerted on other parts, and there is a risk that this part will be damaged.

Furthermore, in the prior art, there is a risk that the corrosive electrolyte contained in the electrodes of the fuel cell may penetrate into the filler, causing corrosion of the cooling pipes and the like.

The present invention has been made in view of the above points,
The purpose is to provide a cooling device for a fuel cell that has a filler that has good thermal conductivity, can reduce thermal deformation of the cooling pipe, and can absorb stress caused by thermal expansion of the cooling pipe.

In addition to the above-mentioned purpose, another purpose is to provide a fuel with a filler that can prevent the corrosive electrolyte contained in the electrodes of the fuel cell from penetrating the filler and corroding cooling pipes, etc. An object of the present invention is to provide a cooling device for batteries.

[Means for Achieving the Object] An object of the present invention is to provide a cooling pipe through which a refrigerant for cooling a fuel cell flows, a cooling pipe holding plate provided with a groove for arranging the cooling pipe, and a cooling pipe holding plate provided with a groove for arranging the cooling pipe. In a fuel cell cooling device configured with a filler filled between the tube and the tube, the filler is a mixed carbon powder formed by mixing two groups of carbon powder belonging to different particle size ranges. This is achieved by a cooling device for fuel cells.

Another object of the present invention is to provide a fuel cell equipped with a filler made of a mixed carbon/resin powder formed by mixing two groups of mixed carbon powders belonging to different particle size ranges and a fluororesin powder. This can be achieved by using a cooling system.

[Operation] When mixing two groups of carbon powders belonging to different particle size ranges, between carbon powders belonging to large particle size ranges
Carbon powder belonging to the small particle size range enters the
The packing density is higher than when using carbon powder of one particle size, resulting in better thermal conductivity. In addition, since only powder is used as the filler, unlike the case of using thermosetting resin, thermally conductive grease, etc. in the conventional technology, all the spaces are not filled, and the gap is reduced. It remains. Due to the presence of this gap, the mixed carbon powder has room to deform, and can absorb stress caused by expansion/contraction, vibration, etc. of the cooling pipe, and furthermore, friction is reduced. In particular, this method works more effectively against stress caused by an increase in the volume of cooling pipes, etc., than the conventional technology that uses grease in a closed space.

Furthermore, when fluororesin powder is included as a filler, its water-repellent action can prevent penetration of the electrolytic solution contained in the electrodes of the fuel cell, thereby preventing corrosion of the cooling pipe.

[Example] The present invention will be described below based on the illustrated example.

An embodiment of the present invention is shown in FIGS. 1-3. As shown in the figure, the cooling device inserted between the unit cells of a fuel cell consists of a cooling pipe holding plate 1 and a bottomed groove 2 provided in the cooling pipe holding plate 1.
A cooling pipe 3 disposed in the interior and through which a refrigerant flows
and a filler filled between the cooling pipe 3 and the bottomed groove 2, and an insulating layer 4 is provided on the outer periphery of the cooling pipe 3.

The cooling pipe holding plate 1 is provided with bottomed grooves 2 for embedding the cooling pipes 3 at intervals of 20 mm. In this bottomed groove 2,
The mixed powder 5 is a mixed carbon consisting of two groups of carbon powders belonging to different particle size ranges, which is a mixture of carbon powder with a particle size range of 5 to 30 μm and carbon powder with a particle size of 50 to 150 μm in a weight ratio of 3:5. Powder 5a was added. Then, in this bottomed groove 2, a metal cooling pipe 3 is buried, which has been provided with an insulating layer 4 coated with a heat-resistant insulating material such as fluororesin. After embedding, the upper space was further filled with mixed carbon powder 5a, and carbon plates 6 were stacked and combined to prevent the filled mixed carbon powder 5a from scattering to form a set of cooling devices. In this case,
In order to increase the heat transfer efficiency between the cooling tube 3 and the cooling tube holding plate 1, the mixed carbon powder 5a to be filled has a volume ratio of 60 to 70% in space, and stainless steel is used for the cooling tube 3.

Using the fuel cell cooling device configured as above,
Although thermal expansion and contraction were repeated at a battery operating temperature of 200°, no breakage was observed in the insulating layer 4 of the cooling tube 3, and the heat transfer efficiency was equivalent to that of a conventional paste filler.

The reason why no breakage was observed in the insulating layer 4 is that two groups of mixed carbon powders 5a belonging to different particle sizes were used as the mixed powder 5 serving as the filler.

That is, two particles belonging to different particle sizes as fillers
By using the mixed carbon powder 5a of the group, the carbon powder belonging to the small particle size range is inserted between the carbon powders belonging to the large particle size range, and the packing density is 1.
The cost is higher than when using carbon powder with one particle size.
As a result, thermal conductivity becomes good. Therefore, deformation of the cooling pipe 3 due to thermal expansion and contraction can be reduced.

In addition, since only powder is used as the filler, unlike the case of using thermosetting resin, thermally conductive grease, etc. in the conventional technology, all the spaces are not filled and the space is not filled. 〓 remains.
Due to the presence of this gap, the mixed carbon powder has room to deform, and can absorb stress caused by expansion/contraction, vibration, etc. of the cooling pipe, and furthermore, friction is reduced. In particular, this method works more effectively against stress caused by an increase in the volume of cooling pipes, etc., than the conventional technology that uses grease in a closed space. Therefore, friction between the cooling tube 3 and the cooling tube holding plate 1 can be reduced, deformation of the cooling tube 3 due to thermal expansion and contraction can be absorbed, and destruction of the insulating layer 4 can be prevented.

Another embodiment of the invention is shown in FIG. In this example, a paste layer 7 was provided by applying a paste over the filled mixed carbon powder 5a. In this case, there is no need to provide a carbon plate as in the case described above, and it is possible to prevent the mixed carbon powder 5a, which is the mixed powder 5, from scattering more easily than in the case described above.

FIG. 5 shows yet another embodiment of the invention.

In this example, the mixed powder 5 was a mixed carbon/resin powder 5b formed by mixing two groups of carbon powders belonging to different particle size ranges and a fluororesin powder. That is, the mixed carbon/resin powder 5b is mixed with the aforementioned mixed carbon powder and 1 fluorine resin powder with a particle size of 30μ or less.
It was prepared by adding and mixing at a weight ratio of 5%. In this case, since it contains fluororesin powder, its water-repellent action can prevent the electrolyte contained in the electrodes of the fuel cell from penetrating, thereby preventing corrosion of the cooling pipe 3. .

[Effects of the Invention] As described above, the present invention provides a cooling device for a fuel cell that can reduce thermal deformation of a cooling pipe and is equipped with a filler that can absorb stress caused by thermal expansion of the cooling pipe. be able to.

Furthermore, it is possible to obtain a cooling device for a fuel cell that includes a filler that can prevent a corrosive electrolyte contained in the electrodes of the fuel cell from penetrating into the filler and corroding cooling pipes and the like.

[Brief explanation of drawings]

FIG. 1 is a perspective view of one embodiment of the fuel cell cooling device of the present invention, FIG. 2 is a cross-sectional view of the same embodiment, FIG. 3 is a longitudinal sectional view of the same embodiment, and FIG. 4 is a longitudinal sectional view of the same embodiment. FIG. 5 is a cross-sectional view of still another embodiment of the fuel cell cooling device of the present invention. 1... Cooling tube holding plate, 2... Bottomed groove, 3... Cooling tube, 4... Insulating layer, 5... Mixed powder (filler),
5a...Mixed carbon powder, 5b...Mixed carbon/resin powder, 6...Carbon plate, 7...Paste layer.

Claims (1)

[Scope of Claims] 1. A cooling pipe through which a refrigerant for cooling the fuel cell flows, a cooling pipe holding plate provided with a groove in which the cooling pipe is disposed, and a cooling pipe filled between the groove and the cooling pipe. A fuel cell cooling device comprising a filler, wherein the filler is a mixed carbon powder formed by mixing two groups of carbon powders belonging to different particle size ranges. Cooling device for batteries. 2 The particle size range of the second group of carbon powders forming the above mixed carbon powder is 5 to 30 μm and 50 to 150 μm.
The first claim characterized in that
A cooling device for a fuel cell as described in . 3 The above mixed carbon powder has a particle size range of 5 to 30 μm.
and carbon powder having a particle size range of 50 to 150 μm, mixed in a weight ratio of 3:5. 4 For the space between the groove and the cooling pipe,
The volume ratio of mixed carbon powder filled in this space is 60
A cooling device for a fuel cell according to claim 1, 2, or 3, characterized in that the cooling amount is 70%. 5. A fuel cell system comprising a cooling pipe through which a refrigerant for cooling the fuel cell flows, a cooling pipe holding plate provided with a groove for arranging the cooling pipe, and a filler filled between the groove and the cooling pipe. In the fuel cell cooling device configured, the above-mentioned filler is a mixed carbon/resin powder formed by mixing two groups of mixed carbon powders belonging to different particle size ranges and fluorine resin powder. Features of fuel cell cooling device. 6 The particle size range of the two groups of carbon powders forming the above mixed carbon powder is 5 to 30 μm and 50 to 150 μm.
m, and the particle size of the above fluororesin powder is 30μ
6. The cooling device for a fuel cell according to claim 5, wherein the cooling device is less than or equal to m. 7. The cooling device for a fuel cell according to claim 4 or 5, wherein a mixing ratio of the fluororesin powder to the mixed carbon powder is 1 to 5% by weight. 8. A cooling pipe including a cooling pipe through which a refrigerant for cooling the fuel cell flows, a cooling pipe holding plate provided with a groove for arranging the cooling pipe, and a filler filled between the groove and the cooling pipe. A fuel cell cooling device configured includes a filler made of mixed carbon powder formed by mixing two groups of carbon powders belonging to different particle size ranges, and a paste layer provided on top of the filler. A cooling device for a fuel cell, characterized in that it is configured with: 9 The particle size range of the two groups of carbon powders forming the above mixed carbon powder is 5 to 30 μm and 50 to 150 μm.
Claim 8 characterized in that
A cooling device for a fuel cell as described in . 10 The above mixed carbon powder has a particle size range of 5 to 30 μm.
9. The cooling device for a fuel cell according to claim 8, wherein carbon powder having a particle size range of 50 to 150 μm is mixed in a weight ratio of 3:5. 11 Claims 8 and 9, characterized in that the volume ratio of the mixed carbon powder filled in this space to the space between the groove and the cooling pipe is 60 to 70%. Alternatively, the fuel cell cooling device according to item 10.