Hydrogen Energy Core Gas Diffusion Layer

Hydrogen Energy Core Gas Diffusion Layer – Fuel Cell Coating – Cheersonic

1、Overview
The gas diffusion layer plays an important role in the fuel cell by supporting the catalytic layer, collecting the current, conducting the gas and discharging the reaction product water. The processes occurring on the gas diffusion layer include: heat transfer process, gaseous transport process, two-phase flow process, electron transport process, surface droplet kinetics process, etc., which require good mass transfer, heat transfer and electrical conductivity, plus it needs to have a certain mechanical strength to support the membrane electrode, good mechanical strength is naturally essential.

2、Material selection
GDL is divided into four types of materials, carbon fibre paper, carbon fibre woven fabric, non-woven fabric and carbon black paper. Carbon fibre paper and carbon fibre cloth, with its macroscopically ordered or microscopically disordered arrangement of fibre structures establish the pore structure for gas and water conduction. During long-term experiments and applications, it has been found that carbon fibre paper is more suitable for use in durable fuel cells due to its light weight, flat surface, corrosion resistance, uniform porosity and high strength, and the thickness can be adjusted according to the requirements of use. Carbon paper has also become the mainstream choice for gas diffusion layer materials due to its mature manufacturing process and stable performance. The base material of carbon paper comes from carbon fibres, and it is the core difficulty of making carbon fibres into carbon paper.

3、The Preparation Process
Due to the different raw materials and preparation processes, there are differences in the performance of the diffusion layer materials obtained. From the point of view of the production process, the preparation of gas diffusion layer, resin coating curing, high temperature graphitization heat treatment, hydrophobic layer, microporous layer coating and other processes are basically the same, in the front section of the carbon fiber preparation of the original paper link there are three technologies: wet (paper method) process; dry non-woven production process; carbon fiber weaving process. In contrast, the wet technology uses a water dispersion system, resulting in a good paper uniformity, which is conducive to improving the porosity, pore size distribution and other indicators, and is conducive to the production of thin gas diffusion layer.

4、Performance requirements
The thickness of the GDL and the surface pre-treatment affect the heat and mass transfer resistance and are one of the main sources of differential polarisation and ohmic polarisation in the whole hydrogen fuel cell system. Therefore, the development of GDL materials with reasonable hydrophobicity, flat surface, uniform porosity and high strength is a key technology for hydrogen fuel cells.

In recent years, there have not been too many iterative, disruptive technologies for electric stacks and membrane electrodes, and the state of the art in the production of gas diffusion layers is correspondingly more mature and process stable. It is expected that the production process of the gas diffusion layer will not change much in the next few years, but will be in the process of continuous optimisation. Optimisation is mainly reflected in thinning, which reduces conduction resistance and improves stack polarisation; at the same time the production scale is expanded, costs are reduced, and online control and digital management are improved. The uniformity control of the carbon paper will greatly affect the yield of the product. As the membrane electrode current operating conditions and performance continue to improve, the gas diffusion layer material has more influence on the performance of fuel cell applications under high current operation, and the heat dissipation and drainage of GDLs are of increasing concern to users.

About Cheersonic

Cheersonic is the leading developer and manufacturer of ultrasonic coating systems for applying precise, thin film coatings to protect, strengthen or smooth surfaces on parts and components for the microelectronics/electronics, alternative energy, medical and industrial markets, including specialized glass applications in construction and automotive.

Our coating solutions are environmentally-friendly, efficient and highly reliable, and enable dramatic reductions in overspray, savings in raw material, water and energy usage and provide improved process repeatability, transfer efficiency, high uniformity and reduced emissions.

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