Extending Battery Lifetime of Electric Mining Vehicles through Thermal and Duty Cycle Management

We have performed a study to identify how aspects such as driving cycle, thermal management, and road conditions impact the lifetime of a battery pack in electric mining vehicles. Many factors including safety, lifetime and the available power of li-ion batteries are influenced by temperature. With a direct impact on cell aging and degradation; battery thermal management can therefore be considered a key component of electric vehicles. Collaborating on a project with Nouveau Monde Graphite (NMG), the company set to build the world’s first fully-electric open pit mine, we analyzed the impact of both the battery thermal management and the duty cycle on the battery lifetime of a typical electric hauling vehicle. We first built a system level model of the electric truck based on a known diesel hauling truck (Western Star 6900) in the software ADVISOR. We then defined various hauling paths in the software, observing and calculating the impact of ambient temperature, initial battery temperature and depth-of-discharge variations at the end of each cycle. A cell aging model for the three available commercial NMC cells was then used to evaluate the cell lifetime based on 70% cell end-of-life criteria. Presented in this study are the effect of temperature on battery aging as well as our recommendations for duty cycle modifications to maximize the battery lifetime.