Principal investigator: Elham Sahraei
University: Temple University
Industry partner: ROEL POWER LLC
High energy density lithium-ion battery storage systems have contributed to the advances in portable electronics and finally enabled the introduction and growth of electric vehicles and drones. In transportation applications, during crashes, these batteries can be subjected to mechanical impact and deformation. Such abusive loadings can cause failure of cell components, resulting in an internal electric short circuit, uncontrolled release of energy, and in extreme cases fires and explosions. Extensive computational and modeling work has shed light on the factors affecting deformation and rupture of a polymeric separator, causing the cell electrodes to short. However, one factor overlooked in various studies is the failure of the electrode current collectors, thin metal foils, which precede and contribute to failure of the separator. Failure of these foils leads to localization of deformation in the separator, ultimately causing its rupture. Therefore, the strains causing a short circuit in batteries is often much smaller than the rupture strain of the separator. In the proposed research, we intend to demonstrate that use of high ductility current collectors can increase the robustness of the cell under mechanically abusive conditions. We anticipate that by preventing the preceding failure of the current collectors, the robustness of the cell can increase by five times, to the level of ductility of the polymeric separator. The proposed research will involve experimental and modeling work followed by prototype manufacturing of an impact resistant cell. The impact resistant cell prototype will then go under extensive characterization of electrical properties and mechanical robustness to provide a proof for the concept. More mechanically robust cells will have system level benefits, allowing battery pack designers to reduce the weight and volume of pack enclosure components designed to protect cells from the crash loads. Reduced pack weight improves vehicle efficiency (km/kwh) while reduced volume increases design options.