C-SMC Crashworthiness for Automotive Battery Case Application

The electrification process of the car industry has brought a series of new challenges in the automotive world. The need of containing, supporting and protecting the battery modules, requires a series of contrasting objective, namely the robustness of the structure, its weight and the overall cost. A promising material class to satisfy these requirements can be found in carbon fibre sheet moulding compounds (C-SMC). This material can be used to produce geometric complex, lightweight applications in a cost efficient compression moulding process, overcoming typical drawbacks of conventional carbon fibre systems. In order to utilize the C-SMC material in the design process of the automotive battery case, simulation models were calibrated in three stages: (1) Coupon-level tests to calibrate the material models, (2) quasi-static 3 and 4-point bending tests of a hat profile geometry for the validation of the macro behaviour on the sub-component level and (3) dynamic sled tests of the hat profile in a 3-point bending set-up to investigate the crashworthiness of C-SMC with impact speeds up to 10 m/s. The macroscopic material behaviour was modelled by a stochastic fibre orientation representing the underlying mesostructure. The Hashin failure criteria with a continuum damage model was employed to predict the onset of damage and ultimate failure. The experimental material data allowed the simulation of the mechanical behaviour of the whole battery system both under normal operating condition coming from road excitation as well as for crash events. The positive outcome of the simulation exposed the full potential of adopting the C-SMC material as a choice for structural parts in EV, resulting in a lightweight although mechanically sound battery casing.