Proton exchange membrane fuel cell bipolar plate with variable cross-section flow field channel

Abstract

The invention provides a proton exchange membrane fuel cell bipolar plate with a variable cross-section flow field channel. The bipolar plate comprises a bipolar plate body, a plurality of flow field channels distributed in parallel are arranged on the bipolar plate body along the flow direction of reaction gas, each flow field channel consists of a plurality of sections A and B which are continuously distributed at intervals and are communicated with each other, the section area of the section A is continuously decreased in the reaction gas flowing direction, the section area of the section B is continuously increased in the reaction gas flowing direction, the section A and the section B are the same in length, the positions of the section A and the section B between two adjacent flow field channels correspond to each other, and the section shapes of the section A and the section B at the connecting part are the same. The section change of the section A and the section B can be change of the groove width or change of the groove depth. When reaction gas flows through, pressure difference is formed between the sections A and B of the adjacent channels, the reaction gas can circulate across the channels, the reaction efficiency of the membrane electrode can be effectively improved, generated water which is difficult to discharge in the area below the ridge of the flow field can be taken away, and the risk of water logging of the battery is reduced.

Description

technical field [0001] The invention belongs to the technical field of proton exchange membrane fuel cells, and in particular relates to a proton exchange membrane fuel cell bipolar plate with variable cross-section flow field channels. Background technique [0002] Proton exchange membrane fuel cell is a device that generates electricity through the electrochemical reaction of hydrogen and oxygen, and the reaction product is water. It is a clean energy source with broad application prospects and great potential. The core of the proton exchange membrane fuel cell is the MEA component and the bipolar plate. The MEA component is to place two carbon fiber paper electrodes sprayed with Nafion solution and Pt catalyst on both sides of the pretreated proton exchange membrane, so that the catalyst is close to the proton exchange membrane. Molded at a certain temperature and pressure, the bipolar plate is used to provide gas distribution channels for hydrogen and oxygen, isolate fue...

AI Technical Summary

Problems solved by technology

The bipolar plate is used in the proton exchange membrane fuel cell to support the fixed membrane electrode assembly, separate the fuel gas (hydrogen) and the oxidizing gas (oxygen or air), allow the reactant gas to be evenly distributed on both sides of the proton exchange membrane and react efficiently, collect and conduct As an important component of the current, the design of the fuel cell bipolar plate and flow field will directly affect the fluid distribution and water management of the anode and cathode reactants of the fuel cell, thereby affecting the efficiency of the fuel cell

The most common forms of flow field channels in the existing bipolar plate design include parallel channel flow field, multi-channel serpentine flow field and interdigitated flow field. It is difficult for the gas medium to penetrate into the area corresponding to the ridge between the flow field channels, resulting in a small gas concentration in the diffusion layer in this area, and the electrochemical reaction efficiency on the membrane is low, resulting in uneven reactions on the membrane. The accumulated water under the ridge is not easy to discharge, and it is easy to cause water flooding and channel blockage, which affects the reaction efficiency and reduces the life of the equipment; the interdigitated flow field is a flow field with intermittent flow channels, and the intermittent flow channels will force the fluid to enter into diffusion by forced convection Layer, which drives the flow and discharge of liquid water in the gap of the diffusion layer, solves the aforementioned problems to a certain extent, but the interdigitated flow field will increase the pressure drop at the inlet and outlet, because the intermittent flow channel structure The inherent resistance is relatively large, and the reaction fluid with a high flow rate can easily cause a large impact on the diffusion layer, resulting in local overheating and damage to the diffusion layer. At the same time, an excessive pressure drop will increase energy consumption and reduce the working efficiency of the battery.

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