Novel stepped hydrophobic gas diffusion layer and preparation method thereof

Abstract

The invention discloses a novel stepped hydrophobic gas diffusion layer and a preparation method thereof, which relate to the technical field of fuel cells, so as to reduce water accumulation in the under-ridge gas diffusion layer and improve the overall performance and stability of the membrane electrode. The gas diffusion layer comprises a common hydrophobic region and an enhanced hydrophobic region which are matched with the bipolar plates, bipolar plate runners and bipolar plate ridges which are distributed in a staggered manner are arranged on the adjacent sides of the two bipolar plates,and the outer wall of one side, close to the bipolar plate ridges, of the enhanced hydrophobic region is matched with the bipolar plate ridges in position and size. The preparation method of the gasdiffusion layer comprises the following steps of weighing a carbon powder material and an additive, adding carbon powder and the additive into a solvent, and carrying out ultrasonic oscillation for 0.5-4 hours to fully disperse the carbon powder and the additive. Enhanced hydrophobic treatment is carried out on the gas diffusion layer part below the ridge of the bipolar plate, so that the hydrophobicity of the gas diffusion layer part in contact with the ridge of the bipolar plate can be improved, water accumulation in the gas diffusion layer below the ridge is reduced, and water logging is reduced.

Description

technical field [0001] The invention relates to the technical field of fuel cells, in particular to a novel stepped hydrophobic gas diffusion layer and a preparation method thereof. Background technique [0002] A fuel cell is a chemical device that directly converts the chemical energy of fuel into electrical energy. Among them, the proton exchange membrane fuel cell is the most promising category among all current fuel cell classifications. It uses hydrogen as the anode fuel, air Or oxygen is the cathode oxidant, which has the characteristics of high energy conversion efficiency (40%-60%), normal temperature working temperature, environmentally friendly emissions, fast start-up speed, and long working life. In various application scenarios, Especially in terms of automobile power and mobile power supply, there has been a certain scale of demonstration and commercial operation in the world, and it is known as the most promising power generation technology. [0003] The gas...

AI Technical Summary

Problems solved by technology

In the actual operation of the fuel cell, the flow channel of the bipolar plate is in direct contact with the base side of the expanded hole of the gas diffusion layer, and the corresponding gas diffusion layer under the ridge of the bipolar plate is directly subjected to the pressure from the bipolar plate, and the porosity is obviously lower than that of the bipolar plate. The corresponding gas diffusion layer under the flow channel should be small, and the water in the gas diffusion layer under the ridge is far away from the flow channel, the drainage path is long, and the water is difficult to discharge in time, causing the water to accumulate under the ridge, which is easy to cause flooding

[0004] After searching, the Chinese Patent Publication No. is CN107507983A, which discloses a diffusion layer with a gradient change in hydrophobicity and its preparation method and application. The diffusion layer with a gradient change in hydrophobicity includes a porous substrate and a microporous layer. There is a vertical hydrophobic layer on the porous substrate, and the micropores of the microporous layer have parallel hydrophobic layers with gradient changes in hydrophobicity; the above patents have the following disadvantages: the processing steps are complicated, and the hydrophobicity gradient is difficult to implement in actual operation. Achieved without consideration of moisture accumulation in the gas diffusion layer under the ridge of the bipolar plate

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