With the aim of lowering the cost of battery manufacturing, Henkel and Covestro have developed a joint solution that enables the efficient fixation of cylindrical Li-ion battery cells inside a plastic cell holder. The design is based on a UV-curing adhesive from Henkel and a UV-transparent polycarbonate blend from Covestro.
Henkel’s Loctite AA 3963 battery assembly adhesives and Covestro’s UV transparent polycarbonate blend Bayblend were developed for compatibility with high-volume automated dispensing techniques. The acrylic adhesive was formulated for use with the cell holder, which is constructed of a special flame-retardant plastic. The developers claim that the combination provides strong adhesion to the substrate material and offers production adaptability through long open times and short cure cycles.
“High-volume manufacturing operations with short cycle times and process flexibility are essential,” explains Frank Kerstan, Head of e-Mobility Europe at Henkel. “The Loctite OEM-approved adhesive designed to secure cylindrical Li-ion cells into a carrier is a one-part, cure-on-demand formulation. After high-speed dispensing, the material’s long open time inherently builds adaptability into the process by allowing for any unexpected production interruption. Once all cells are placed into the adhesive and secured in the holder, curing is activated with UV light and takes place in less than five seconds.” Henkel describes this as an advantage over conventional manufacturing, in which curing times can range from several minutes to hours, thus requiring additional storage capacity for parts.
The cell holders are manufactured from Covestro’s PC+ABS blend Bayblend FR3040 EV, which meets category V-0 of Underwriters Laboratories’ UL94 flammability rating. “The material allows us to construct dimensionally stable parts that are necessary for automated mass assembly,” says Steven Daelemans, Market Development Manager at Covestro. “Together with the fast-curing capability of the Loctite adhesives, this material combination delivers an innovative approach to large-scale cylindrical Li-ion battery module production.”