JPH11283660A - Solid electrolyte fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the temperature of current collecting members, to reduce the thermal stress due to the difference of the thermal expansion coefficient between unit cells and the current collecting members and to prevent the breakage and peeling of the current collecting members by making the current collecting members hollow, and feeding a heat medium in hollow sections. SOLUTION: Unit cells 1 aligned in the same direction are connected together vertically and horizontally via conductive felts 2, the unit cells 1 on the uppermost stage and lowermost stage are connected to current collecting members 4a, 4b via the conductive felts 2 respectively, and electric power is taken out from the opposite current collecting members 4a, 4b. Hollow sections 7 are provided on the current collecting members 4a, 4b respectively, a heat medium is fed to the hollow sections 7 to control the temperature of the current collecting members 4a, 4b, the displacement quantities by heat of junctions between the unit cells 1 and the current collecting members 4a, 4b are made equal, the thermal stress by the difference of the linear expansion coefficient is reduced, and the occurrence of troubles such as the breakage of the unit cells 1 and the current collecting members 4 or the peeling of the junctions can be prevented. When temperature is lowered, the specific resistance of the current collecting members 4 is reduced, and power generation efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel cell using a solid electrolyte, and more particularly to a current collecting member of a solid electrolyte fuel cell to which a single cell is connected.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, a single cell 1 is connected to a plate-like current collector 10 via a conductive felt 2, and furthermore, a connection portion between the single cell 1 and the conductive felt 2 is provided. In addition, the contact state between the conductive felt 2 and the connection portion of the current collector plate 10 is deteriorated, and the electric resistance during this period is not increased.
The connection was fixed.

[0003]

However, when the connection as in the conventional example is made, thermal stress is generated due to a difference in linear expansion coefficient between the single cell and the current collecting member in the operation cycle of starting, operating, and stopping. In addition, there is a possibility that a problem such as breakage of the single cell or the current collecting member and separation of the conductive felt from the single cell or the conductive felt and the current collecting member may occur.

[0004] The present invention reduces thermal stress due to the difference in linear expansion coefficient between a single cell and a current collecting member, breaks the single cell or the current collecting member, and reduces the conductive felt and the single cell or the conductive felt and the current collecting member. An object of the present invention is to provide a current collecting member that can solve problems such as peeling.

[0005]

In order to achieve the above object, the temperature of the current collecting member is controlled by making the current collecting member hollow and flowing a heat medium through the hollow portion. Thus, the thermal stress caused by the difference in the linear expansion coefficient between the single cell and the current collector can be reduced.

FIG. 1 is a model diagram in which a single cell 1 and a current collecting member 4 are connected via a conductive felt 2. The linear expansion coefficient of the connecting portion of the single cell is α _C , the connecting portion of the current collecting member is α. temperature of the connection portion of the linear expansion coefficient alpha _E, temperature t ₀ and the current collecting member temperature difference Delta] t _C, the thermal stress is not generated between the temperature t ₀ which thermal stress is not generated and the temperature t _C of the connecting portion of the unit cell When the temperature difference between t _E and Delta] t _E, respectively the displacement amount of heat per unit length α
_C Δt _C , α _E Δt _E , and a thermal stress corresponding to this difference is generated. Here, each of the displacement amount becomes equal, i.e. such that the _{α C Δt C = α E Δt} E, by controlling the Delta] t _E the temperature of the current collecting member internally flushed with heat medium collecting member, heat Stress can be reduced. Note that even when α _C Δt _C and α _E Δt _E are not completely equal, the effect of reducing the thermal stress can be sufficiently exhibited.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In order to clarify the contents of the present invention, description will be made below using examples. FIG. 2 is a cross-sectional view schematically showing one embodiment of the present invention, in which unit cells 1 are arranged in the same direction, and unit cells 1 vertically adjacent to each other in the figure are conductive felts at the position of the interconnector 3. 2, and the unit cells 1 adjacent to the left and right in the figure are also connected via the conductive felt 2. The unit cell 1 at the top of the figure is connected to the current collecting member 4a via the conductive felt 2, and the unit cell 1 at the bottom of the figure is connected to the current collecting member 4b and the conductive felt at the position of the interconnector 3. 2
Connected through. Furthermore, to prevent the contact state of the connection part from becoming worse and the electrical resistance during this time from increasing,
The connection is fixed. Electric power is taken out by a pair of opposing current collecting members 4a and 4b. A hollow portion 7 is provided in the current collecting member 4a and the current collecting member 4b.
A heat medium is caused to flow therethrough so that the temperature of the current collecting member 4a or 4b can be controlled.

[0008] The method of the present invention is not limited to the above embodiment, and various other embodiments can be adopted without departing from the scope of the present invention. FIG. 3 shows an example of another embodiment.

As described above, the present invention has the following effects by the above configuration. The current collecting member according to claim 1, wherein a heat medium flows through the hollow portion of the current collecting member, and the connection between the single cell and the current collecting member fixed through a conductive felt forms the single cell and the current collecting member. By controlling the temperature of the current collecting member so that the amount of displacement of the member due to heat becomes equal, the thermal stress can be reduced, the single cell or the current collecting member is damaged, and the conductive felt and the single cell or the conductive felt and the collecting member are collected. Problems such as peeling of electrical members can be solved.

The use of a current collector provided with a hollow portion facilitates manufacture, as compared with the use of an inclined member having the same linear expansion coefficient at the connection between the unit cell and the current collector.

Further, when the temperature of the current collecting member is controlled to be reduced by the heat medium, the specific resistance of the current collecting member can be reduced, the loss due to the electric resistance of the current collecting member can be reduced, and the power generation efficiency can be reduced. Is also improved.

[Brief description of the drawings]

FIG. 1 is a diagram schematically illustrating a model of a connection unit.

FIG. 2 is a sectional view schematically showing an embodiment of the present invention.

FIG. 3 is a sectional view schematically showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view schematically showing a current collecting member of a conventional solid oxide fuel cell.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Single cell 2 ... Conductive felt 3 ... Interconnector 4 ... Current collecting member 4a ... Current collecting member 4b ... Current collecting member 7 ... Hollow part 10 ... Current collecting plate

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Takaharu Nakayama 2-147, Shiobara, Minami-ku, Fukuoka City, Fukuoka Prefecture Inside Kyushu Electric Power Co., Inc. (72) Hiroaki Tajiri 2, Shiobara Minami-ku, Fukuoka City, Fukuoka Prefecture No. 1-47, Kyushu Electric Power Co., Inc.

Claims (1)

[Claims] 1. A solid oxide fuel cell, wherein the current collector is made hollow and a temperature of the current collector is controlled by flowing a heat medium through the hollow portion.