44 January/February 2024 | E-Mobility Engineering Peter Donaldson finds complex challenges within the development of coatings for battery applications Bending the laws of physics Coatings play a crucial role in battery cells, modules and packs. Evolving continuously, they are engineered to enhance performance, safety, reliability and longevity in these complex, high value electrochemical systems. While the active materials that constitute the core components of cells – the anode and cathode – are applied to their substrates as coatings, this article will focus mainly on the supporting players. These are coatings that perform functions such as electrochemical protection, thermal management, fire protection, dielectric insulation, or serve as barriers against moisture and contaminants. They may not be the stars of the show, but the show won’t go on without them. Functional variety Inside the cells, coatings are applied to enhance mechanical and thermal stability; particle coatings to improve the cycle life of active materials and conductivity of the current collector foils, to reduce cell resistance and improve adhesion of the active material on these foils, explains Dr. Tobias Knecht, battery cells specialist at Henkel. The company is working on a variety of different products ranging from fire resistant coatings of battery lids, metal pre-treatments that suppress corrosion of battery housings, dielectric coatings for that are typically applied on battery cans and conductive coatings of current collector foils. Also within the cell are coatings that go on to the separators. The separators themselves are selective insulators generally made from polymer materials that block the movement of electrons but allow ions to pass through them, so they are fundamental components of cells. Increasingly, coatings are applied to separators to enhance their electrical isolation. “We want to make sure electricity can flow in some places but is not able to flow in others,” says Calum Munro, associate fellow at PPG. Coatings on the outer surface of each
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