JPS6014769A - Fuel cell - Google Patents

Abstract

PURPOSE:To feed reaction gas uniformly while to make thin a cell, by forming a current collector board with metal fiber mat added with Ni, or Ni added with Cr or Co. CONSTITUTION:Predetermined amount of fiber metal having the diameter of 10-100mum and the length of 1-10mum is put into organic solvent or aqueous solution added with organic binder such as methyl-cellulose, polyvinyl alcohol and agitated sufficiently. Then said solution is left standstill or filtered through paper or cloth to produce fiber metal mat. Thereafter, said metal fiber mat is heated under the temperature of 800-1,100 deg.C to produce a porous and mechanically strong mat where small chips of fiber metal are sintered each other. The sintered porous metal mat can be utilized as a current collector board.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to fuel cells, and in particular,
This invention relates to a fuel cell using molten carbonate as an electrolyte.

As shown in Figure 2, the current collector plate/ is equipped with a large number of through holes 6 as gas flow paths, and nickel metal is generally used in consideration of its corrosion resistance against molten salt. It has a thickness of The fuel side electrode is a porous electrode made of a sintered body whose main component is nickel metal powder. The electrolyte layer 3 is a porous structure mainly composed of LiA10□.
It consists of 1□CO3 mixed with carbonate such as 2C03.

The oxidant side electrode has a porous structure similar to the fuel side electrode. This oxidizer side electrode may be made of N1 sintered body or NiO sintered body, but in any case, in the operating state of the battery, it becomes NiO with a small amount of Li ions added (Nio Q, i+). There is. Oxidizer side electrode q
The current collector plate j is made of stainless steel and has the same structure as the current collector plate of the fuel side electrode. Although the shape of the through holes 6 in the current collector plates 1 and S does not necessarily have to be circular, they are generally circular holes with a diameter of 1 to 3 recesses.

Next, the operation of this type of molten carbonate fuel cell will be explained. A fuel cell generates electricity directly through an electrochemical reaction between a fuel gas such as H2 and an oxidant gas such as air. In order to carry out this type of electrochemical reaction effectively, porous electrodes are generally used.

The reactions at the fuel side electrode and the oxidant side electrode are as follows.

(Fuel (11!I) H2+ Co3-> H2t]
-Co2+, ze (1) - (oxidizing agent side) Co2+ -20□+Coe-+C03 (2)
In other words, at the fuel side electrode λ, the fuel, H2, is transferred to the electrolyte layer 3.
It reacts with CO1- inside to generate water, CO□, and electrons, and at the oxidizer side electrode, CO2, oxidizer O2, and electrons flowing through an external load react to generate Co3. The cell reaction proceeds by dissolving into the electrolyte layer 3. This will be explained using FIG. First, the fuel gas is allowed to flow to the current collector plate 1, where it passes through the through hole 6 of the current collector plate 1 and is carried to the fuel side electrode. The reaction of formula (1) above proceeds in the fine pores of this fuel-side electrode. On the other hand, also on the oxidizing agent side, the oxidizing agent gas supplied from the through hole 6 of the current collector plate S reacts according to equation (2).

Conventional fuel cells were constructed as described above, so when supplying gas from the current collector plate to the electrodes, it was difficult to supply the reactant gas uniformly, and in order to maintain mechanical strength, There were drawbacks such as the need to use a fairly thick plate of about 2 m.

Furthermore, since the diameter of the micropores, which are important for the electrodes of this type of fuel cell, is controlled only by powder sintering technology, it is difficult to obtain the desired porosity.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and by using a fibrous metal mat as a current collector plate, it has high mechanical strength and can evenly supply fuel gas. The object of the present invention is to provide a fuel cell equipped with a current collector plate.

Another object of the present invention is to provide a fuel cell equipped with a current collector plate made of a fibrous metal mat made of nickel, stainless steel matachal nickel, and chromium, cobalt nickel, etc. added thereto.

Hereinafter, this invention will be explained with reference to examples. First, a fibrous metal having a wire diameter of 10 to 1θθμm and a length of 1A to 1θ is prepared. This fibrous metal can be obtained by cutting a round bar.

Next, a predetermined amount of fibrous metal is placed in an organic solvent or aqueous solution and stirred sufficiently to ensure uniform dispersion.

Adding an organic binder such as methyl cellulose or polyvinyl alcohol to the solution at this time facilitates uniform dispersion of the fibrous metal. This solution is then allowed to stand or is filtered with paper or cloth to create a fibrous metal mat. The finished product has a paper-like shape. The above process can also be easily accomplished by applying paper-making techniques used to make so-called Japanese paper. By heating the fibrous metal mat thus obtained at a temperature of ~/100[deg.] C., the fibrous metal pieces are sintered together to form a porous mat with strong mechanical strength.

When this sintered porous metal mat is used as a current collector plate, a fuel cell with uniform gas supply can be obtained.

Next, some embodiments will be described in more detail.

Example / First, the wire diameter JO~! ; 01t1rL, length/~!
rm fibrous Nirakeruko θgr is prepared. Next, prepare thimethylcellulose 21, add Henickel fiber therein, and stir thoroughly. Next, this solution is transferred to a container with a bottom area of about 100 cr and left to stand. After this, the supernatant liquid is discarded and the precipitate is dried. After drying thoroughly,
It was pressurized at a pressure of about lθky/cd. After that, gθ
Methyl cellulose is decomposed and removed by heating at 0° C. for 30 minutes. Furthermore, in a hydrogen atmosphere, at 1000℃, 7
It was heated for 5 minutes to sinter the nickel fibers together. The obtained fibrous nickel mat has a film thickness of 0. II v+m
Met. Figure 3 shows an enlarged cross-sectional view of the fibrous nickel pine door. It is composed of a sintered body of a.

When a fuel cell is assembled using the metal mat made of the porous membrane of fibrous nickel 7a obtained here as a current collector plate button of the fuel side electrode, uniform diffusion of fuel gas to the electrodes is achieved.

Example: Fibrous nickel with a wire diameter of 30 to SO μm and a length of l to 3 mm,
Prepare 10gr and nickel/gr. This is poured into a polyvinyl alcohol aqueous solution (SOML) and thoroughly stirred, and then spread on a substrate such as a Mylar film. After sufficiently drying, the obtained film is peeled off from the substrate film and pressed at a pressure of about tokg/cd. Then, Daθ
Polyvinyl alcohol is decomposed and removed by heating at θ°C for 30 minutes. After this, qoo℃ under hydrogen atmosphere.
, io minutes to sinter. Fibrous nickel pine obtained here)/? An enlarged cross-sectional view of is not shown in FIG. Fibrous nickel mat/7 is composed of fibrous nickel a and nickel powder 7b. Nickel powder 7 as shown in the figure
b plays the role of binding the fibrous nickel 7a together. The use of this as the current collector plate on the fuel side is the same as in Example.

In addition, the metal decay component of the metal mat is nickel g.

Suitable results could be obtained with the components in the range of ~1θθ, chromium θ ~20%, and cobalt θ ~ -0-.

Furthermore, in the above embodiments, a case has been described in which a fibrous nickel mat is used as the current collector plate on the fuel side, but other metal mats such as a stainless steel mat can also be obtained in a similar manner.

In particular, stainless steel mat has excellent corrosion resistance, so when used as the current collector plate of the oxidizing agent side electrode, it produces the same effects as in the above embodiment.

In this case, the stainless steel side slope is stainless steel J10
．． ．． J/l, or 3 liters is suitable.

As described above, the present invention has the effect of uniformly supplying reactive gas and making the battery thinner by configuring the current collector plate with a metal mat made of sintered fibrous metal. be·

[Brief explanation of the drawing]

FIG. 1 is an exploded side view of a conventional molten carbonate fuel cell, FIG. FIG. 2 is an enlarged sectional view of a main part of another embodiment. L...Current plate of fuel side electrode, C...Fuel side electrode, 3...
Electrolyte layer, S... current collector plate of oxidizer side electrode, 6... through hole, 7. /7...Fibrous nickel matte, 7a...Fibrous nickel, 7b...Nickel powder. In each figure, the same reference numerals indicate the same or corresponding parts. Agent: Masuo Oiwa yf) 1 illustration, 2 illustrations

Claims (1)

[Scope of Claims] (1) The fuel-side electrode and the oxidizer-side electrode sandwiching the electrolyte layer are provided with the current collector plate formed of a porous metal mat made of a sintered body of fibrous metal. A fuel cell featuring: (λ) The fibrous metal has a wire diameter of 1o-ioθμm and a length of l~/
The fuel cell according to claim 1, which has a θ range. (3) The fuel cell according to claim 1, wherein the fibrous metal components are in the range of 10-100% nickel, 0S-20% chromium, and 20% cobalt θ. (4') The fuel cell according to claim 3, wherein nickel powder is added to form a metal mat. (,lt) The fuel cell according to claim 1, wherein the fibrous metal is stainless steel.