Dynamic mechanical behaviors of load-bearing battery structure upon low-velocity impact loading in electric vehicles

As the electrification trend of vehicles continues, new energy vehicles such as electric vehicles (EVs) and plug-in hybrid electric vehicles (PHEVs) are being equipped with new functional energy storage devices demanding a trade-off between electrical and mechanical property. Accordingly, composite-battery integrated structures which simultaneously carry mechanical resistance and energy-storage capacity, are being explored to offer great potential for the next generation of EVs or PHEVs. Herein, the dynamic responses and failure mechanisms of the integrated structure under the commonly occurring low-velocity impact events are studied both experimentally and numerically. A macro-scale finite element (FE) model was developed by implementing constitutive models of component materials, including lithium-ion polymer (LiPo) battery cells, polymer foams, and carbon fiber-reinforced polymers (CFRP). The numerical method demonstrates good feasibility and accurately predicts impact behaviors, with the maximum error of the peak impact load not exceeding 8 %. The integrated structures are proven to reduce mechanical damage while maintaining mechanical and electrochemical performance within a range of impacts. The electrical and mechanical behaviors and their correlations were revealed. Sensitivity of the mechanical behaviors and electrical failure to battery arrangement were discussed as well as the structure design on energy absorption capacity. These results hold significant potential for the safety and lightweight design of energy storage composite structures incorporating lithium-ion batteries.