Robust Design on Adhesive Material and Bonding process for Automotive Battery Pack 2019-01-0160

Adhesive bonding is a key technology for the lighter weight of battery pack trays using aluminum material. We developed a robust design method of adhesive bonding with the required strength for battery pack structure after degradation. The word “robust” means minimized variability of strength under various noise conditions. The parameter design based on Taguchi methods determined the optimum adhesive condition of the bonding process. To guarantee strength after degradation, it is essential to select a robust adhesive material and to minimize the strength variation derived from the adhesive material. The functional evaluation, which includes experimental design method, determined adhesive material with the minimum strength variation among material candidates. Then, robustness of the adhesive material itself has been evaluated as the result of collaboration with the adhesive material supplier. This analysis determined to regulate compounding ratio of raw materials without reducing the adhesive strength. By optimizing the adhesive condition after the above evaluation, the SN ratio, as the measure of robustness, increased in 7.11 dB and the average strength increased in 6.4 MPa compared to the conventional one. This indicates that the proposed approach can control the adhesive strength after the degradation and shows potential of adhesive bonding for battery-pack structure application.