Special-shaped fuel cell gas diffusion layer, preparation method, fuel cell and assembly method

Abstract

The invention discloses a special-shaped fuel cell gas diffusion layer, a preparation method, a fuel cell and an assembly method. The special-shaped fuel cell gas diffusion layer comprises a carbon fiber base material layer and a microporous layer which are sequentially stacked, and at least one side of the carbon fiber base material layer is provided with convex parts and concave parts which arecontinuously and alternately arranged, so that the side surface is of a convex-concave special-shaped structure. The special-shaped fuel cell gas diffusion layer has a convex-concave special-shaped structure; therefore, when the gas diffusion layer and the bipolar plate are assembled, the gas diffusion layer is prevented from being pressed into a runner of the bipolar plate in the assembly processof the gas diffusion layer and the bipolar plate to cause reduction of gas diffusion performance and drainage performance in a mode that the convex part of the diffusion layer is in contact with theridge part of the bipolar plate and the concave part corresponds to the runner area. Meanwhile, the convex part is gradually thinned to the same thickness as the gas diffusion layer in the concave part area in the compression process of assembling the convex part and the concave part, and the gas diffusion layer is prevented from being broken by shear stress in the ridge and groove transition area.

Description

technical field [0001] The invention relates to the technical field of fuel cells, and relates to a special-shaped fuel cell gas diffusion layer, a preparation method, a fuel cell and an assembly method. Background technique [0002] The gas diffusion layer is a porous carbon-based material that sits between the fuel cell catalyst layer and the bipolar plates and controls the fuel cell's mass transport, heat transport, and electron transport. At the same time, it provides mechanical protection and support for the catalytic layer and membrane during assembly and operation. The gas diffusion layer generally consists of a carbon fiber substrate layer and a microporous layer. At present, the gas diffusion layer used is a flat plate structure with a uniform thickness. After the fuel cell is assembled, the gas diffusion layer in the area corresponding to the ridge of the bipolar plate will be thinned and deformed under the action of pressure, resulting in a gap between the bipola...

AI Technical Summary

Problems solved by technology

As disclosed in CN103427099B, the anode gas diffusion layer with graphite flake filling adjusts the water management characteristics inside the fuel cell by adjusting the diffusion resistance in the anode and cathode gas diffusion layers, the carbon fiber substrate of the gas diffusion layer is directly connected to the bipolar Plate contact, its contact resistance with the bipolar plate is relatively large, and the gas diffusion layer is a flat plate structure, which cannot eliminate the problem of the gas diffusion layer being pressed into the flow channel of the bipolar plate

The gas diffusion layer in CN110190295A includes: a conductive porous substrate layer, a hydrophobic low-humidity adaptation layer and a microporous low-pressure adaptation layer, and the gas diffusion layer is prepared by coating and heat treatment. The gas diffusion layer is a flat structure, which cannot eliminate the gas diffusion layer entering The problem of performance degradation caused by the runner

CN102082277A utilizes high-temperature sintering, closed-field unbalanced magnetron sputtering ion plating technology and coating technology to prepare a metal gas diffusion layer. Although the gas diffusion layer uses low-priced stainless steel fibers as raw materials, the metal fibers are punctured. risk of the membrane, but also the unavoidable risk of entry into the flow channels of the bipolar plate and the risk of crush breakage

[0004] The gas diffusion layers disclosed in the above documents are all multi-layer material composite structures, and they are all planar structures. When the gas diffusion layer is used in conjunction with the bipolar plate, due to the effect of clamping pressure, it is inevitable that part of the gas diffusion layer will Extruded into the bipolar plate medium flow channel, resulting in increased medium transmission resistance, weakened drainage performance, uneven gas distribution on the surface of the catalytic layer, and even breakage near the ridges and grooves of the flow channel, seriously affecting the performance and life of the fuel cell

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