Method for producing membrane electrode assembly

Abstract

The present invention relates to a Membrane Electrode Assembly (MEA) which significantly enhances power density as well as structural reliability and method for producing the same. More specifically, it relates to the Membrane Electrode Assembly which has a plurality of protuberances and method for producing the same. The present invention involves making supporting bodies to have a plurality of protuberances on one side of the supporting bodies, forming a catalyst layer on one side of the supporting bodies having the protuberances, interposing a polymer-electrolyte-membrane between the supporting bodies, aligning the supporting bodies for the protuberances to engage each other; and hot-pressing the aligned supporting bodies. The present invention can increase the area of a three-phase boundary in which oxidation-reduction reaction of hydrogen and oxygen occurs and decrease resistance to ion conduction; consequently fuel cells have the characteristic of a large output of power density.

Description

TECHNICAL FIELD [0001] The present invention relates to a Membrane Electrode Assembly (MEA) having the characteristic of a large output of power density and structural reliability and method for producing the same. More specifically, it relates to the Membrane Electrode Assembly, which is used generally in fuel cell power generation by using oxygen and hydrogen as fuel and method for producing the same. BACKGROUND ART [0002] Recently, problems relating to the rapid increase in the demand for power, depletion of fossil fuels, and environmental pollution have become more and more serious. Therefore, interest in a fuel cell that can resolve the problems of this environmental pollution along with the supply and demand of energy has been increasing more and more. [0003] The general efficiency of an internal combustion engine is 10˜20%, however, the fuel cell can increase efficiency over 75% by using the heat generated in the fuel cell. Also, the quantity of nitrogen compound or sulfur co...

AI Technical Summary

Benefits of technology

[0048] Still another object of the present invention is to increase the reaction surface area of the three-phase boundary in which the electric chemical reaction occurs.

[0049] Still another object of the present invention is to provide the producing method having a good reproducibility by decreasing the sliding occurring in the hot-pressing process of membrane electrode assembly.

[0050] Still another object of the present invention is to provide the membrane electrode assembly having a structural reliability against exterior vibration generated while operating the fuel cell or assembling of the stack.

[0051] Still another object of the present invention is to decrease ohmic resistance to hydrogen ion passing through the polymer electrolyte membrane by decreasing the thickness of the polymer electrolyte membrane.

[0052] Still another object of the present invention is to increase the output density of the membrane electrode assembly compared with a conventional flat membrane electrode assembly coated with the same material catalyst.

[0053] Still another object of the present invention is to lessen the number of the membrane electrolyte assemblies and the separators needed in manufacturing the fuel cell stack as compared with a conventional flat membrane electrode assembly in the same output power.

Problems solved by technology

Recently, problems relating to the rapid increase in the demand for power, depletion of fossil fuels, and environmental pollution have become more and more serious.

However, improving the performance of the membrane electrode assembly through the above-mentioned method may be difficult.

However, it is difficult to lower the thickness of polymer electrolyte membrane because of mechanical solidity.

However, there is no the polymer electrolyte membrane that complies with the qualifications mentioned above.

However, the above-mentioned method that can increase the effective surface area of a platinum particle by using a small quantity of a catalyst can't give prominent performance improvement.

However, a high possibility exists that the degree of homogeneousness becomes low and contact resistance becomes high in a preponderance of pressure because the polymer electrolyte and the electrodes are contacted on flat side.

On the contrary, no method exists for increasing a reaction effective method or decreasing the contact resistance through improving the structure of the membrane electrode assembly.

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