JPS5998473A - Molten carbonate type fuel cell - Google Patents

Abstract

PURPOSE:To offer such a fuel cell as being provided with a current outlet terminal capable of forming a continuous rating current passage, by performing no drilling or perforating, etc., for an insulating material and an adiabatic material. CONSTITUTION:Composed of a good conductive material, each of current outlet terminals 21a and 21b of a fuel cell consists of a current collector plate 31 formed in crosswise size equal to that of an end face of a layer-built body X, a groove 32 installed in this collector plate 31, a current outlet plate 34 installed projectingly in the extension of this groove 32 and an insulating layer 35 of aluminum oxide formed on both surfaces of this current outlet plate 34 and the collector plate 31 as thick as 300mum by means of a plasma spray process, for example. Therefore, since the current outlet plate 34 extends over in a direction of being crossed to the layer direction of the layer-built body X within the range of thickness in the collector plate 31, it can dispense with the necessity of installing any hole to lead the current outlet plate 34 into each of insulating materials 12a and 12b and an adiabatic material 14.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a molten carbonate fuel cell, and more particularly to a fuel cell having an improved current extraction terminal structure.

[Background technology of the invention and its problems]

Conventionally, fuel cells have been widely known that generate DC power by reacting a gas that is easily oxidized, such as hydrogen, with a gas that has oxidizing power, such as oxygen, through an electrochemical reaction process. .

Fuel cells are broadly classified into cynic acid type, molten carbonate type, solid electrolyte type, etc. depending on the electrolyte used.

By the way, among the above-mentioned fuel cells, molten carbonate fuel cells are designed to operate at temperatures around 650°C, and their main parts are usually constructed as shown in Figure 1. There is. That is, an electrolyte layer 1 formed by integrating a carbonate electrolyte such as lithium carbonate or potassium carbonate and a ceramic support material such as lithium aluminate into a flat plate.
A nickel alloy-based gas diffusion species 2 is formed on both sides of the electrolyte layer 1, with only one dimension narrower than the vertical and horizontal dimensions of the electrolyte layer 1.
A * 2b are applied perpendicularly to each other to constitute a unit battery 3, and a laminate X is constructed by laminating a plurality of unit batteries with bipolar separators 4 interposed between them.

Each bipolar separator 4 includes a separator main body 5 formed of a stainless steel plate or the like with vertical and horizontal dimensions equal to the vertical and horizontal dimensions of the electrolyte layer 1, and a separator main body 5 formed on both sides of the separator main body 5. The grooves 6 are perpendicular to the plurality of grooves 6 which constitute a passage A through which fuel gas flows, as shown in , and the grooves 6 which constitute a passage B through which oxidizing gas flows, as shown by thick arrows Q in the figure. It is composed of a plurality of grooves 7. Valley groove 6
, 7 are formed parallel to the central part of the separator main body 5 excluding the side parts C and D, and on both sides of the part where these grooves 6 and 7 are provided, the opposite side edges of the gas diffusion species described above are formed. A locking step portion 8 a r 8 b for locking is formed.

That is, the gas diffusion species 2 a + 2 b have one surface in contact with the electrolyte layer 1 as shown in FIG. 7
) is formed in a size that allows it to be held in position while in contact with the convex portion that makes up the part. and the groove 6 of the separator body 5.
, 7 are not provided, so as to seal the gas.

Therefore, in a molten carbonate fuel cell whose main part is constructed as described above, the current extraction terminals 11h and llb are generally applied to both end surfaces of the laminate X, as shown in FIG. , insulating plates 12a + 12b are placed on the outside thereof, and these insulating plates 12a.

12b are integrated by tightening them with insulating bolts 13 at the outer corners of the laminate X, and furthermore, a manifold (not shown) is provided for flowing each of the aforementioned gases through the four sides of the laminate X. They are press-connected and the outer surfaces of these manifolds and the outer surface of the insulating plate 12a are covered with a heat insulating material 14 to form one power generation unit.

The current extraction terminals 11a and 11b are normally connected to a current collector plate 15 made of a highly conductive material that is pressed against the end surface of the laminate X, and to the back surface of the current collector plate 15 at right angles to the current collector plate 15. The current extraction plate 16 has holes 17 and 18 provided in an insulating material and a heat insulating material.
It is designed to be led to the outside through. Note that 19 in the figure indicates an insulating material.

However, in the conventional molten carbonate fuel cell configured as described above, 'C' is the current extraction terminal 11h, l
Since lb is formed in a so-called T-shape, insulating plates 12a and 12 must be connected in order to lead out current extraction plate 16 to the outside.
b and holes 17 in the insulation material 14. There was a problem in that it was necessary to provide an Ig, and the entire production required a long time. In particular, in the case of molten carbonate fuel cells, since they operate in a high temperature range of 650°C, it is desirable to use alumina or silica-based ceramic materials with excellent heat insulation properties as the heat insulating material 14. . However, these ceramic materials have poor mechanical strength, so drilling must be done with great care, resulting in long manufacturing times.
However, there is a problem in that the mechanical strength of the ceramic material after drilling is further reduced.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and its purpose is to allow the insulation material to pass through the insulation material without having to drill holes or the like, without having any adverse effects on other materials. An object of the present invention is to provide a molten carbonate fuel cell equipped with a current extraction terminal capable of forming an electric path.

[Summary of the invention]

The molten carbonate fuel cell according to the present invention has a current extraction plate comprising a current collector plate and a current extraction plate provided to extend parallel to the current collecting surface of the current collector plate within the thickness range of the current collector plate. It is characterized by a built-in terminal.

〔Effect of the invention〕

With the above configuration, the current extraction plate of the current extraction terminal is
It extends within the thickness range of the current collector plate □ and in a direction perpendicular to the lamination direction of the laminate. Therefore, unlike conventional fuel cells, there is no need to provide a hole for passing the current extraction plate through the insulating plate used for tightening or the insulating material placed outside the insulating plate, and as a result, ceramic material is used as the insulating material. It is possible to realize the ease of fabrication by making it possible to use it. In addition, since the current extraction plate is located within the thickness range of the current collector plate, there is a possibility that the clamping characteristics of the laminate through the current collector plate may be adversely affected.
This does not adversely affect the press-fitting of the manifold, and after all, it is possible to simplify manufacturing without adversely affecting others.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows only the essential parts of a molten carbonate fuel cell according to an embodiment of the present invention, and the same parts as in FIG. 3 are designated by the same reference numerals. Therefore, the explanation of the overlapping parts will be omitted.

The difference between the fuel cell according to this example and the conventional one is that
Current extraction terminals 21 are press-connected to both end faces of the laminate X.
a, 21b. In other words, the current extraction terminal J 1
a e J 1 b, as shown in FIG. A groove 32 is formed on a surface opposite to the surface in which the groove 32 is located, and a highly conductive material is formed with a thickness equal to the depth of the groove 32 and a width equal to the width of the groove 32, with a part of the groove 32 A current extraction plate 34 is fixed to the current collecting plate 31 by countersunk screws 33 or welding in a filling relationship, and the remaining portion is provided to protrude from the groove 32 on an extension of this groove 32, and this current extraction plate 34 and an insulating layer 35 of aluminum oxide formed to a thickness of about 300 μm by, for example, a plasma spray method, on the surface of the current collector plate 31 located on the opposite side to the surface located on the side of the laminate X. .

With such a configuration, the current extraction plate 34 extends in the direction perpendicular to the lamination direction of the laminate X within the thickness range of the current collector plate 31, so that the insulating material 12 &
, 12b and the heat insulating material 14 can eliminate the need to provide holes for guiding the current extraction plate 34. Furthermore, with the above configuration, the surface of the current extraction terminal 21a (21b) that contacts the insulating materials 12a, 12b can be flattened, and each part of the surface can be uniformly brought into contact with the insulating materials 12a, 12b. Therefore, by using the insulating port 13, the tightening characteristics can also be improved. In addition, since the gas seal of the manifold can be performed within the thickness range of the current collector plate 31 and at the end face of the greatest part where the groove 32 is formed, the above configuration does not require any change in the gas seal configuration. , the above-mentioned effect can be obtained.

It goes without saying that the current extraction terminal will not fail unless it has not only electrical conductivity but also corrosion resistance.

[Brief explanation of drawings]

Fig. 1 is an exploded perspective view of the main parts of the molten carbonate fuel cell, Fig. 2 is a local side view of the main parts, Fig. 3 is a vertical cross-sectional view of the main parts of the cell, and Fig. 4 is the main part of the cell. FIG. 5 is a longitudinal cross-sectional view of a main part of a molten carbonate fuel cell according to an embodiment, and a perspective view of a current extraction terminal, which is one of the main parts constituting the main part. X... Laminated body, 21a*21b... Current extraction terminal, 31... Current collector plate, 32... Groove, 34... Current extraction plate, 35... Insulating layer. Applicant Makoto Ishiita, Director of the Agency of Industrial Science and Technology - Figure 1 Figure 2 Figure 3 Prisoner Figure 4 Figure 5 (21b)

Claims (1)

[Claims] A plurality of unit fuel cells each having a carbonate electrolyte layer interposed between a pair of gas diffusion electrodes, between these unit fuel cells,
It comprises a laminated body laminated with bipolar separators having fuel gas passages and oxidant gas passages on both sides, and a pair of current extraction terminals electrically connected to both end faces of this laminated body. In the molten carbonate fuel cell, each of the current extraction terminals includes a current collector plate made of a highly conductive material that is provided in pressure contact with an end surface of the laminate, and a surface of the current collector plate located on the laminate side. It is formed to have a thickness equal to the depth of the groove provided on the opposite side and a width equal to the width of the groove, and is fixed to the current collector plate in such a manner that a portion thereof fills the groove. and a current extraction plate provided with a remaining portion protruding from the groove on an extension of the groove, and a surface of the current extraction plate and the current collector plate located on the opposite side to the surface located on the laminate side. A molten carbonate fuel cell comprising: an electrically insulating layer provided thereon;