JPH04370664A - Fuel cell - Google Patents

Abstract

PURPOSE:To prevent drop of the power generation efficiency and deterioration of the battery performance by allowing the fuel gas and oxidating agent gas to flow uniformly in a fuel gas passage and an oxidating agent gas passage. CONSTITUTION:An electrolyte plate 1 is pinched by an anode and a cathode, and a passage 26 for flowing of the fuel gas 19 is provided on the counter plate 1 side about the anode while a passage 27 for flowing of oxidating agent gas 20 is furnished on the counter plate 1 side about the cathode. The passage 26 is so formed that its section area is increment from the incoming side toward the outgoing side, while the passage 27 is so arranged that its section area is decremental from the input side toward the output side.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to fuel cells.

0002

2. Description of the Related Art A conventional fuel cell will be explained below with reference to FIGS. 6 to 11.

As shown in FIGS. 8 to 10, a rectangular electrolyte is produced by impregnating a porous material with a carbonate such as lithium carbonate or potassium carbonate, or by press-molding the carbonate together with a holding material. A plate 1 is provided, and the electrolyte plate 1 is connected to an anode 2.
(positive electrode) and a cathode 3 (negative electrode), and the anode 2 and cathode 3 are sandwiched between punch plates 4 and 5, each having a large number of holes punched therein. A cell 10, which is a basic unit, is constructed by sandwiching the corrugated plates 8 and 9 to secure a space for the flow path 7, and as shown in FIG.
A stack 12 is constructed by laminating multiple layers with a center plate 11 parallel to the center plate 11 interposed therebetween.

The anode 2, cathode 3, and punch plates 4 and 5 are housed in frame-shaped mask plates 13 and 14, which are formed smaller than the electrolyte plate 1 and whose planar shape is shown in FIG. , mask plate 13,1
The outer edge of the center plate 4 is joined to the outer edge of the center plate 11 to seal the fuel gas flow path 6 and the oxidant gas flow path 7.

In the stack 12 having the above structure, an electrolyte plate 1 and a center plate 11 are provided at one end side of the fuel gas passage 6 and the oxidizing gas passage 7 in the cells 10 of each layer, as shown in FIGS. 7 to 9. and a fuel gas supply path 1 that vertically penetrates the mask plates 13 and 14 and communicates with the fuel gas flow path 6.
Oxidizing gas supply passages 16 communicating with the oxidizing gas passages 7 are alternately formed.

Similarly, as shown in FIGS. 7 to 9, an electrolyte plate 1, a center plate 11, and a mask plate 13 are provided on the other end sides of the fuel gas flow path 6 and the oxidizing gas flow path 7 in the cells 10 of each layer. , 14 and are alternately formed with fuel gas discharge passages 17 communicating with the fuel gas passage 6 and oxidizing gas discharge passages 18 communicating with the oxidizing gas passage 7.

[0007] Also, the fuel gas flow path 6 and the oxidant gas flow path 7
As shown in FIG. 11, the cross-sectional area of the flow path is constant from one end to the other end.

In the figure, 19 is a fuel gas whose main components are hydrogen and carbon monoxide, 20 is an oxidant gas whose main components are oxygen and carbon dioxide, and 21 is a fuel gas formed below the stack 12. A supply port, 22 is an oxidant gas supply port formed on the lower side of the stack 12, 23 is a fuel gas discharge port formed on the lower side of the stack 12, and 24 is an oxidant gas formed on the lower side of the stack 12. It is an outlet.

The fuel gas 1 is supplied from the fuel gas supply port 21 on the lower side of the stack 12 to the fuel gas supply path 15.
9 is distributed to the fuel gas passages 6 in the cells 10 of each layer, contacts the anode 2 through the holes in the mask plate 13 in the fuel gas passages 6 of each layer, and the fuel gas 19 at the anode 2
After some of the hydrogen inside reacts with carbonate ions to generate water (steam) and carbon dioxide, it is collected from the fuel gas flow path 6 in the cells 10 of each layer to the fuel gas discharge path 17, and is discharged to the lower side of the stack 12. The oxidizing gas 20 discharged from the fuel gas outlet 23 of the stack 12 and supplied to the oxidizing gas supply path 16 from the oxidizing gas supply port 22 on the lower side of the stack 12 flows through the oxidizing gas flow path in the cells 10 of each layer. The oxidizing gas flow path 7 of each layer contacts the cathode 3 through the hole in the mask plate 14, and at the cathode 3, part of the oxygen and carbon dioxide in the oxidizing gas 20 contacts the cathode 3 and becomes carbonic acid. After generating ions, the oxidizing gas flow path 7 in the cells 10 of each layer
The oxidant gas is collected from
The oxidizing gas is discharged from the lower oxidizing gas outlet 24, and at this time, electricity is generated by the potential difference generated between the anode 2 and the cathode 3 due to the reaction of the fuel gas 19 at the anode 2 and the reaction of the oxidizing gas 20 at the cathode 3. be exposed.

0010

[Problems to be Solved by the Invention] However, the above conventional fuel cells have the following problems.

That is, the reaction at the anode 2 is a volume increase reaction in which steam and carbon dioxide are generated from hydrogen and carbonate ions, and the reaction at the cathode 3 is a volume decrease reaction in which carbonate ions are generated from oxygen and carbon dioxide. Despite this, the cross-sectional area of the fuel gas flow path 6 and the oxidizing gas flow path 7 was set to a constant size from one end to the other end as shown in FIG. In the gas flow path 6, the pressure of the fuel gas 19 increases as it progresses from one end to the other, while in the oxidant gas flow path 7, the pressure of the oxidant gas 20 increases as it progresses from one end to the other end. This will result in a decrease.

[0012] Therefore, the flow of the fuel gas 19 and the oxidant gas 20 within the fuel gas flow path 6 and the oxidant gas flow path 7 becomes non-uniform, causing a decrease in power generation efficiency and deterioration of battery performance.

In view of the above-mentioned circumstances, the present invention prevents a decrease in power generation efficiency and deterioration of battery performance by uniformly flowing fuel gas and oxidant gas inside the fuel gas flow path and the oxidant gas flow path. The object of the present invention is to provide a fuel cell which can obtain the following characteristics.

[0014]

[Means for Solving the Problems] The present invention has an electrolyte plate sandwiched between an anode and a cathode, and a fuel gas passage through which fuel gas can flow is provided on the side of the anode opposite to the electrolyte plate, and a fuel gas passage is provided on the side of the cathode opposite to the electrolyte plate. An oxidant gas flow path through which the oxidant gas can flow is provided, and the fuel gas flow path is formed so that the cross-sectional area of the flow path increases as it progresses from the inlet side to the outlet side. The present invention relates to a fuel cell characterized in that the cross-sectional area of the flow path decreases as it progresses toward the outlet side.

[0015]

[Operation] According to the present invention, the reaction of the fuel gas at the anode is a volume increase reaction, and the reaction of the oxidant gas at the cathode is a volume decrease reaction. By forming the oxidizing gas flow path so that the flow path cross-sectional area increases as it progresses from the inlet side to the outlet side, the oxidant gas flow path is formed so that the flow path cross-sectional area decreases as it progresses from the inlet side to the outlet side. The pressure of the fuel gas and the pressure of the oxidant gas in the oxidant gas flow path become constant, and the fuel gas and the oxidant gas flow uniformly in the fuel gas flow path and in the oxidant gas flow path, respectively.

[0016]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 4 show one embodiment of the present invention.

Further, in the drawings, the same components as those in FIGS. 6 to 11 are given the same reference numerals, and a description thereof will be omitted, and only the structures unique to the present invention will be described below.

By arranging the center plate 25 diagonally with respect to the electrolyte plate 1, the volume of the fluid flowing inside the fuel gas passage 26 increases as it advances from the fuel gas supply passage 15 side to the fuel gas discharge passage 17 side. The oxidant gas flow path 27 has a shape in which the cross-sectional area of the flow path increases accordingly, and the flow rate decreases as the oxidant gas flow path 27 progresses from the oxidant gas supply path 16 side to the oxidant gas discharge path 18 side. Shape that reduces the cross-sectional area of the road.

Next, the operation will be explained.

FIG. 6 shows the process by which the fuel cell generates electricity.
- Since it is similar to FIG. 11, the explanation will be omitted.

The reaction at the anode 2 is a volume increase reaction in which steam and carbon dioxide are generated from hydrogen and carbonate ions, and the reaction at the cathode 3 is a volume decrease reaction in which carbonate ions are generated from oxygen and carbon dioxide. In the present invention, by arranging the center plate 25 diagonally with respect to the electrolyte plate 1, the volume of fluid flowing inside the fuel gas flow path 26 as it progresses from the fuel gas supply path 15 side to the fuel gas discharge path 17 side is reduced. The oxidant gas flow path 27 has a shape in which the cross-sectional area increases as the oxidant gas increases, and as the oxidant gas flow path 27 progresses from the oxidant gas supply path 16 side to the oxidant gas discharge path 18 side, the volume of the fluid flowing therein decreases. Since the cross-sectional area of the flow path is reduced, the fuel gas 19 flows from the fuel gas supply path 15 side to the fuel gas discharge path 17 side in the fuel gas flow path 26.
The pressure of the oxidizing gas 20 is constant in the oxidizing gas flow path 27 from the oxidizing gas supply path 16 side to the oxidizing gas discharge path 18 side. Fuel gas 1 inside agent gas flow path 27
9 and the oxidant gas 20 become uniform, thereby preventing a decrease in power generation efficiency and deterioration of battery performance.

FIG. 5 shows another embodiment of the present invention, which has the same structure as the embodiment described above except that the electrolyte plate 1 and the center plate 25 are arranged diagonally, and has the same effects. Moreover, since the stack 12 can be made into a rectangular shape, it is more advantageous than the previous embodiment in terms of manufacturing and installation.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention.

[0025]

Effects of the Invention As explained above, according to the fuel cell of the present invention, the fuel gas and the oxidant gas can be uniformly flowed inside the fuel gas flow path and the oxidant gas flow path, so that the power generation efficiency can be improved. It is possible to achieve an excellent effect of preventing the battery from decreasing or deteriorating the battery performance.

[Brief explanation of drawings]

FIG. 1 is an overall side view of an embodiment of the present invention.

FIG. 2 is a diagram similar to FIG. 8 according to the invention;

FIG. 3 is a diagram similar to FIG. 9 according to the invention;

4 is a schematic side view showing the state of the fuel gas flow path and the oxidant gas flow path in FIG. 1. FIG.

FIG. 5 is an overall side view of another embodiment of the present invention.

FIG. 6 is an overall side view of a conventional example.

FIG. 7 is a schematic plan view of the mask plate of FIG. 6;

FIG. 8 is a view taken along arrows VIII-VIII in FIG. 7;

FIG. 9 is a view taken along the line IX-IX in FIG. 8;

FIG. 10 is a view taken along the line XX in FIGS. 8 and 9. FIG.

11 is a schematic side view showing the state of the fuel gas flow path and the oxidant gas flow path in FIG. 6. FIG.

[Explanation of symbols]

1 Electrolyte plate 2 Anode 3 Cathode 19 Fuel gas 20 Oxidizing gas 26 Fuel gas flow path 27 Oxidizing gas flow path

Claims (1)

[Claims] Claim 1: An electrolyte plate is sandwiched between an anode and a cathode, and a fuel gas flow path is provided on the side of the anode opposite to the electrolyte plate through which fuel gas can flow, and an oxidizer gas passage is provided on the side of the cathode opposite to the electrolyte plate through which oxidant gas can flow. The oxidant gas flow path is formed such that the cross-sectional area of the fuel gas flow path increases as it progresses from the inlet side to the outlet side, and the flow path increases as the oxidant gas flow path progresses from the inlet side to the outlet side. A fuel cell characterized by being formed to have a reduced cross-sectional area.