JPH071698B2 - Molten carbonate fuel cell - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of use) The present invention relates to a molten carbonate fuel cell, and in particular, the internal temperature can be maintained for a long time without impairing the assembly workability. The present invention relates to a molten carbonate fuel cell capable of stable and stable measurement.

(Prior Art) In recent years, a molten carbonate fuel cell has been developed as a highly efficient energy conversion device. A molten carbonate fuel cell is one in which an electrolyte composed of an alkali carbonate is melted at a high temperature to cause an electrode reaction, and does not require an expensive precious metal catalyst as compared to other fuel cells such as a phosphoric acid fuel cell. It has major features such as high heat generation efficiency.

By the way, the output of the unit cell of the molten carbonate fuel cell is weak. Therefore, in order to configure a high-output power plant, it is necessary to stack a plurality of unit batteries in series to form a stacked body and obtain the added output of each unit battery.

FIG. 4 shows a structure of a laminated body of a molten carbonate fuel cell which has been conventionally proposed. Each unit cell 1 is composed of a pair of porous electrodes, that is, an oxidant electrode (cathode) 2a and a fuel electrode (asode) 2b, and an electrolyte plate 3 made of carbonate interposed therebetween. These unit batteries 1 are stacked with a conductive separator 4 having both an electrical connection function between the unit batteries 1 and a function of forming a reaction gas supply passage to each electrode plate.

The separator 4 includes a conductive separator plate 5, a side wall member 6a made of stainless steel brazed and fixed to two opposite sides of one surface of the separator plate 5, and the other surface of the separator plate 5. The side wall member 6a is made of, for example, stainless steel and is brazed and fixed to two opposite side portions in a direction orthogonal to the side wall member 6a, and the reaction gas passages 7a and 7b formed by the side wall members 6a and 6b are mounted. It is composed of conductive corrugated plates 8a and 8b that divide the reaction gas. The side wall members 6a and 6b have a function of forming a passage for the reaction gas, a function of holding the porous electrode, and a function of forming a wet seal at a contact portion with the electrolyte plate 3.

As shown in FIG. 5, conductive end plates 9a and 9b (however, the end plate 9b is not shown) are applied to both end faces in the stacking direction of the fuel cell stack X thus configured. And a manifold 10a, 10b, 11a, 11b having a function of distributing and collecting reaction gas on four sides of the fuel cell stack X, which are also frame-shaped seals, as shown in FIG. Applied through material 12. Then, the fuel gas P is supplied to one of the manifolds, and the oxidant gas Q is supplied to the adjacent manifold to supply the fuel cell stack X.
After the two gases are allowed to contribute to the electrode reaction inside the chamber and a DC output is obtained, the exhaust gas can be exhausted from each of the opposing manifolds.

By the way, in the molten carbonate fuel cell configured as described above, it is necessary to constantly monitor the temperature of each part in the stacking direction in the fuel cell stack X during operation to control a cooling system or the like (not shown). Therefore, in the conventional molten carbonate fuel cell, temperature measuring elements are embedded in several separators, and their lead wires 13 are put together as shown in FIG. 5 and, for example, through holes 14 provided in the manifold 10a to the outside. The method of pulling out and connecting to measuring equipment is adopted.

However, in the conventional molten carbonate fuel cell configured as described above, a part of the temperature measuring element and the lead wire 13 connected to the temperature measuring element are brought into contact with the carbonate and the reaction gas at 300 to 800 ° C. Since they are made to corrode, they are corroded and cut in a short time, and there is a problem that temperature measurement becomes impossible. Further, in order to connect the lead wires 13 in the manifold, a welding method must be adopted, and furthermore, a hole 14 provided in the manifold for pulling out the lead wires 13 must be completely gas-sealed. However, there was also a problem that the work required a lot of work.

(Problems to be Solved by the Invention) As described above, in the conventional molten carbonate fuel cell, not only the mounting work of the temperature measurement system becomes complicated, but also the reliability of the temperature measurement system decreases in a short time. there were.

Therefore, an object of the present invention is to provide a molten carbonate fuel cell capable of solving the above-mentioned problems.

[Structure of the Invention] (Means for Solving Problems) In the present invention, a unit battery in which a pair of porous electrodes are arranged on both surfaces of an electrolyte layer containing a carbonate that melts at an operating temperature is provided.
Molten carbon dioxide obtained by laminating a plurality of conductive separators having gas passages on both sides orthogonal to each other, and arranging a manifold for passing a reactive gas through the gas passages on the four side surfaces of the laminated body. In the salt fuel cell, at least one of the separators is provided with a hole extending from the corner side end into the separator constituent material, and a thermocouple for temperature measurement is mounted in the hole.

(Function) Since the thermocouple is installed in the hole described above, it does not come into direct contact with the hot reactive gas or carbonate. Therefore,
The function does not deteriorate due to corrosion. Also,
Since the thermocouple is installed in the hole provided in the above-mentioned part of the separator, the thermocouple can be attached independently of the manifold, and the manifold must be installed in advance so as not to block the inlet of the hole. If formed, the thermocouple can be attached with the battery completely assembled, and the work of attaching the temperature measurement system can be greatly simplified.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

1 to 3 show a molten carbonate fuel cell according to an embodiment of the present invention, and the same portions as those in FIGS. 4 and 5 are designated by the same reference numerals. Therefore, detailed description of the overlapping portions will be omitted.

The molten carbonate fuel cell according to this example has a so-called corner cut shape in which four tops of the fuel cell stack Xa are cut off by a predetermined amount, as is apparent from FIG. Therefore, the electrolyte plate 3, the separator 4, and the end plates 9a, 9b, which are directly involved in the shape of the fuel cell stack Xa, have four corners, as shown in FIG. 21 are formed. Then, each manifold 10a, 10
The flange portions of b, 11a, 11b are formed in a size that does not extend to the corner cut portion 21.

Therefore, as shown in FIGS. 2 and 3, the separators 4 located in the separator 4 every other sheet in the stacking direction are separated from the side end surface of the corner cut portion 21 by separating the inside of the separator plate 5 from the side of the separator plate 5. Dead end hole that extends to a position near the center
22 are provided. The hot junction side of the thermocouple 24 protected by a ceramic tube 23 of alumina or the like is inserted in the hole 22, and the cold junction side of the thermocouple 24 is the first side.
As shown in the figure, it is guided to a measuring device (not shown) through a gap existing between the manifolds 10a and 11b.

With such a structure, the thermocouple 24 does not touch the high temperature carbonate or the reaction gas at all on the cold junction side as well as on the hot junction side. Therefore, the thermocouple 24 can be prevented from being corroded, and as a result, the temperature can be stably measured for a long period of time. Also, regardless of the manifold, the thermocouple
Since the thermocouple 24 can be attached even after the fuel cell is completely assembled, the installation work can be greatly improved, and the assembly of the entire fuel cell can be facilitated. You can

The present invention is not limited to the above embodiment.
That is, in the above-described embodiment, the corner cut portion 21 is provided in each element, but it is not always necessary. However, it is necessary to provide an escape portion that escapes the inlet of the hole 22 in the flange portion of the manifold. In addition, in the above-described embodiment, holes are provided in every other separator in the stacking direction, and the hot junction side of the thermocouple is inserted into these holes. The hot junction side of the thermocouple may be inserted into each of the above. Also, as the separator,
It is also possible to use the one integrally formed by shaving or the like or the one integrally formed with the groove serving as the gas guide passage.

[Effects of the Invention] As described above, according to the present invention, it is possible to provide a molten carbonate fuel cell that can improve the reliability of temperature measurement and the assembly workability.

[Brief description of drawings]

FIG. 1 is a perspective view of a molten carbonate fuel cell according to an embodiment of the present invention, FIG. 2 is a perspective view of a separator incorporated in the fuel cell, and FIG. 4 is an exploded perspective view of a fuel cell stack of a conventional molten carbonate fuel cell, and FIG. 5 is a perspective view of a conventional molten carbonate fuel cell. P ... Fuel gas, Q ... Oxidant gas, Xa ... Fuel cell stack, 1 ... Unit cell, 3 ... Electrolyte plate, 4 ... Separator, 5 ... Separator plate, 6a, 6b ... Side wall Material, 10a, 1
0b, 11a, 11b …… Manifold, 21 …… Corner cut, 22 ……
Hole, 24 ... thermocouple.

Claims (2)

[Claims] 1. A unit battery comprising a pair of porous electrodes arranged on both sides of an electrolyte layer containing a carbonate that melts at an operating temperature,
Molten carbonate obtained by laminating a plurality of conductive separators having gas passages on both sides orthogonal to each other, and arranging manifolds for circulating a reactive gas through the gas passages on four side surfaces of the laminated body. In the fuel cell, at least one of the separators is provided with a hole extending from the corner side end into the separator constituent material, and a thermocouple for temperature measurement is mounted in the hole. And a molten carbonate fuel cell. 2. The molten carbonate fuel cell according to claim 1, wherein the electrolyte layer and the separator have corners cut off.