JPS61110967A - Pressure type fuel cell - Google Patents

Abstract

PURPOSE:To treat so that reaction gas leaked from a cell may not accumulate while heightening efficiency of a pressure type system by setting up a white metal catalyzer inside a pressure container. CONSTITUTION:In the captioned cell, where inert gas pressure inside a pressure container housing a cell is almost equalized to the pressure of each reaction gas to be supplied to the cell, a catalyzer 14 making hydrogen gas leaked from the manifold sealing part into the container 2 to react to air for producing water inside the pressure container 2. For instance, a catalyzer metal such as platinum-palladium is borne by carbon paper and a nickel or stainless steel net for being wrapped in a wire net in order to be fixed to the inside wall of the container 2. Thereby, each reaction gas leaked inside the pressure container is combined into water by an action of the catalyzer so as not to be in danger of accumulating leak gas inside the pressure container while being not required to let a large amount of inert gas into the pressure container so that it safies to seal inert gas into the pressure container or to let flow a small amount of inert gas.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a pressurized fuel cell in which a battery is housed in a pressure vessel.

(b) Conventional technology fuel cells have better reactivity when operated under high pressure;
Pressurized systems have been developed because they offer better properties than normal pressure systems. In this case, each reaction gas is pressurized to about 5 atmospheres and supplied to the battery housed in the pressure vessel, and an inert gas such as N2 or 002 is also supplied to the pressure vessel under the same pressure. be filled.

However, it is unavoidable that each reaction gas (hydrogen gas and air) leaks from the manifold seal portion of the T-cell stack, and the danger increases if this accumulates in the pressure vessel. For this reason, conventional methods include constantly flowing inert gas under pressure into the pressure vessel to send leak gas out of the vessel, and methods that increase the internal pressure of the pressure vessel higher than the pressure of the gas supplied to the battery to suppress leaks from the manifold seal. etc. have been proposed.

However, the former method requires a large-capacity compressor or blower to pressurize a large amount of inert gas and flow it through an open path, which impairs the efficiency of the entire system. In addition, in the latter method, inert gas in the pressure vessel leaks into the battery stack and mixes with each reaction gas, reducing battery reactivity, and temporarily causing the supply pressure on the battery side to rise above the vessel internal pressure during load fluctuations. Both methods were fraught with problems, such as the reactant gas leaking into the container due to the high temperature.

Problems to be Solved by the Invention The present invention aims to prevent reaction gas leaking from batteries from accumulating in a pressure vessel, and to improve the efficiency of a pressurized system.

B) Means for Solving the Problems This invention places a platinum metal catalyst inside a pressure vessel.

(E) Effect According to the present invention, each reaction gas (hydrogen gas and air) leaking into the pressure vessel from the manifold seal etc. is combined into water by the action of the catalyst, and the leak gas is released into the pressure vessel. Since there is no risk of accumulation, it is sufficient to seal inert gas in the pressure vessel or to flow a small amount of inert gas without the need to flow a large amount of inert gas.

(f) Example FIG. 1 is a diagram schematically showing each gas path of a battery housed in a pressure vessel, and FIGS. 2 and 6 are a cross-sectional view and a vertical cross-sectional view of a pressurized fuel cell according to the present invention. It is.

In the schematic diagram of FIG. 1, hydrogen gas and air are supplied under pressure to the negative and positive electrodes of a battery (1), respectively, and the high-temperature exhaust gases discharged from the positive and negative electrodes are sent to, for example, a reformer burner (not shown). is burned. Pressurized gas is supplied to create an inert gas atmosphere inside the pressure vessel (2). These reaction gases and inert gases require pressure adjustment in each system, so pulp (31 < 3r, (41 (41') and (
51 (51').It also has a heat recovery device (6) and a blower (
Pressurized air circulates in the closed circulation circuit (8) having 7) to cool the battery. The amount of pressurized air in this closed circuit (8) is adjusted by Pulp +91 <9r.

Battery (1) has a reaction air manifold (111 (111') and a hydrogen gas manifold (121 (121') installed side by side on one opposing surface of the battery stack αα, and a cooling air manifold ld on the other opposing surface. The inlet pipe and outlet pipe of each of these manifolds are connected to a pressure vessel (
2), and is led out to the outside by airtightly penetrating the bottom wall.

Inside the pressure vessel (2), a catalyst is installed which reacts the hydrogen gas leaked into the vessel (2) through the sealing part of the manifold with air to form water. In the illustrated embodiment, a catalyst metal such as platinum or palladium supported on carbon vapor or nickel or stainless steel mesh is wrapped in a wire mesh or the like and fixed to the inner wall of the container (2).

The reacting gases are the 02 gas in the leaked air and the 2 gases, and there are no impurities, so the catalyst can be used semi-permanently. In addition, the reaction under a catalyst involves 2 moles of H2 gas and 0
The gas is leaked at a ratio of 1 mole of 2 gases, but the amount of leaked gas is 0.2
) Ii2, all of the R2 gas is consumed and 02 gas remains, but the inside of the pressure vessel (2) becomes inert gas and 02 (air), while in the case of R2>02, unconsumed R2 gas remains, but the pressure Inside the container (2) are inert gas and R2 gas.9
There is no danger in either case because R2 gas and 02 gas do not coexist. The generated water becomes water vapor because the temperature inside the container is 160°C or higher, and the pulp (51 (5r) is opened and discharged to the outside of the container (2) together with the inert gas, or the pulp + s + t5f is slightly opened. It can be discharged along with a small amount of inert gas that is constantly flowing.

(g) Effects According to the present invention, hydrogen gas and air (reactant gas/cooling gas) leaked into the pressure vessel from the manifold seal, etc.
Since the oxygen gas inside is consumed by the action of the catalyst installed in the pressure vessel, hydrogen gas and oxygen gas do not accumulate together in the pressure vessel, improving safety. Therefore, there is no need to continue to flow a large amount of pressurized inert gas into the pressure vessel, and it is possible to reduce the capacity of the compressor or blower and the inert gas flow rate accordingly.
It also contributes to improving the efficiency of pressurized fuel cells.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing each gas path of a pressurized fuel cell, and FIGS. 2 and 6 are a cross-sectional plan view and a vertical sectional front view of the pressurized fuel cell according to the present invention, respectively. (1)...Battery, (2)...Pressure vessel, α0)...Battery stack, (111(ILr
...Reaction air manifold, ■Ol...
・Hydrogen gas manifold, α &cry'... Cooling air manifold, 0 phrase... Catalyst.

Claims (1)

[Claims] (1) The pressure of the inert gas in the pressure vessel housing the battery is approximately equal to the pressure of each reaction gas (hydrogen gas and air) supplied to the battery, and the pressure from the battery to the pressure vessel is A pressurized fuel cell characterized in that a catalyst is installed to cause the leaked hydrogen gas to react with the oxygen gas in the air.