In the design of Rechargeable Energy Storage System (RESS) structures, including battery trays, module side plates, and end plates, there are multiple conflating factors, including: Mechanical requirements necessitating the use of electrically conductive materials (steel and aluminum); proximity between battery module structure and battery cells, necessitating the use of electrical isolation coatings; and, module and pack designs that retain cells via the use of Structural Adhesive Material (SAM). Inherently, with this design approach, organic coatings are placed in a new and perilous position. In a sense, the coating becomes a supplement to an adhesive. As Computer-Aided Engineering (CAE) virtual analysis tools become more sophisticated, there is increasing reliance on these tools to predict the occurrence of structural failures in various load cases.
Factors in test method, paint pretreatment, and topcoat affecting adhesion of organic coatings in structural adhesive joints are discussed, including: Adhesive sample preparation; adhesive selection, coating film pretreatment; age of pretreatment bath; acid cleaning; substrate material type (steel vs. aluminum); substrate product form effects within aluminum, and coating thickness.
This information is useful for organic coating process development on metallic substrates. It is especially useful for material constructions requiring paint in contact with structural adhesives, as in these joints, paint adhesion is often a limiting factor on the performance of the structural adhesive. The characterization and optimization of this interface is especially important for EV battery modules & packs.