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Polymer electrolyte fuel cell

A polymer electrolyte and fuel cell technology, applied in the direction of solid electrolyte fuel cells, fuel cells, fuel cell additives, etc., can solve the problems of reduced basic performance of batteries, easy reduction of conductivity of gas diffusion electrodes, uneven diffusion, etc. , to achieve the effect of improving output performance and long-term stable operation

Inactive Publication Date: 2003-04-16
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

With such a configuration, the diffusion amount of gas tends to be non-uniform in the cell surface, or the conductivity of the gas diffusion electrode on the outlet side of the gas diffusion electrode tends to decrease, or the conductivity of the gas diffusion electrode in the cell surface may be uneven. The basic performance of the battery is reduced due to problems such as uniformity

Method used

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  • Polymer electrolyte fuel cell
  • Polymer electrolyte fuel cell

Examples

Experimental program
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Effect test

Embodiment approach I

[0066] [Embodiment [I]: Drainage of Gas Diffusion Layer in Thickness Direction]

[0067] According to the first form in the embodiment [I] of the present invention, the gas diffusion layer constituting the polymer electrolyte fuel cell is provided with a porous carbon support, and the pores are distributed in a direction in which the catalyst layer becomes thinner and the separator side becomes thicker. tilt. That is, the gas diffusion layer has a different pore distribution in the thickness direction. By forming such an inclination, both the discharge of water and the water retention of the catalyst layer can be achieved.

[0068] That is, the moisture in the catalyst layer is held in the catalyst layer by the gas diffusion layer with fine pore distribution. However, if excess moisture is generated, the moisture overflows from the catalyst layer and reaches the gas diffusion layer, and the moisture is introduced into the gas diffusion layer with coarser pore distribution. T...

Embodiment approach I

[0069] A carbon fabric based on a porous carbon support as a constituent element of a gas diffusion layer of a polymer electrolyte fuel cell according to the second aspect of the embodiment [I] of the present invention, in which pores of different sizes are distributed in the plane direction . That is, the pore distribution differs in the plane direction of the carbon fabric. That is, by arranging large pores and small pores, both the drainage of the gas diffusion layer and the gas diffusivity to the catalyst layer can be achieved.

[0070] That is, excess moisture generated from the catalyst layer is introduced into the large pores and quickly discharged from the catalyst layer. At this time, the gas diffuses through the small pores, so that the water discharge channel and the gas channel are separated, so that both the water discharge and the gas diffusibility to the catalyst can be achieved.

[0071] Based on the first and second aspects of the embodiment [I] of the prese...

Embodiment I-1

[0085] First, if figure 2 Schematically, the mesh thickness of the carbon fabric 20 is made so that it is thinner on the side of the catalyst layer and thicker on the side of the separator.

[0086] A wire with a thickness of about 300 microns made by twisting PAN-based fibers with a thickness of about 10 microns is used as the first layer of horizontal yarn 20a, and a wire with a thickness of about 600 microns made by twisting PAN-based fibers with a thickness of about 10 microns is used as the second layer. Two layers of weft yarns 20b are produced by weaving yarns with a thickness of about 600 microns as the second layer of warp yarns 20c and yarns with a thickness of about 300 microns as warp yarns 20d connecting the first and second layers.

[0087] This cloth was heated at 2000° C. for 24 hours in a nitrogen atmosphere to prepare a graphitized carbon cloth. figure 2 A schematic view showing a cross section of the carbon fabric 20 and a surface viewed from the second lay...

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Abstract

The present invention provides a high performance polymer electrolyte fuel cell in which excessive water can be prevented from retaining in the gas diffusion electrode, with the polymer electrolyte membrane being maintained at an appropriately wet condition. The gas diffusion layer is provided with an electrically conductive polymer-containing layer comprising carbon particles and a polymer material. In it, a combination of two kinds of carbon particles having different amounts of acidic function group is used in a manner that the weight ratio of one kind having a larger acidic function group, relative to the other kind, increases from one end of the gas diffusion layer to the other end. Thereby, the water permeating function at the surface of the gas diffusion layer can be so adjusted that the inside of the MEA is maintained at an appropriately wet condition, while excessive water is quickly exhausted to outside of the fuel cell together with e.g. the reactive gas. This can also be achieved by using a combination of two kinds of polymer materials in the electrically conductive polymer-containing layer in a manner that the two kinds have either different degrees of crystallinity or different coefficients of moisture permeability, so that the degrees of crystallinity decreases and the coefficients of moisture permeability increases from the one end to the other end of the gas diffusion layer.

Description

technical field [0001] The present invention relates to a polymer electrolyte fuel cell that can be used as a power generator for residential power generation and waste heat heating systems, and automobiles, and in particular to a gas diffusion layer used therein. Background technique [0002] Polymer electrolyte fuel cells provide fuel gas such as hydrogen and oxidant gas such as air (usually the fuel gas supply side is called the anode, and the oxidant gas supply side is called the cathode), and an electrochemical reaction occurs on a catalyst such as platinum. Therefore, Electricity and heat are generated simultaneously. The general configuration of such a polymer electrolyte fuel cell is shown in FIG. 1 . [0003] In FIG. 1, a catalyst layer 12 mainly composed of carbon powder carrying a platinum-group metal catalyst is bonded to both surfaces of a polymer electrolyte membrane 11 that selectively transports hydrogen ions. Further, an arrangement is made such that a pai...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/86H01M4/88H01M4/92H01M4/96H01M8/04H01M8/10
CPCH01M4/96H01M4/8828H01M4/8642H01M4/8821H01M4/8657H01M4/92Y02E60/521H01M8/04089H01M4/8605H01M4/8652H01M8/1004Y02E60/50H01M4/86
Inventor 吉田昭彦山本雅夫新仓顺二武部安男酒井修内田诚
Owner PANASONIC CORP
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