Battery pack balancing systems for underground mine electric vehicles

This PhD research focuses on the non-uniformity of battery packs in underground mine electric vehicles, which have zero emissions. The non-uniformity in the battery pack is inevitable and can significantly reduce the pack capacity and their service life. This thesis alleviates the side effect of the non-uniformity through a dedicated balancing system and the contributions are summarized as proposing new balancing criteria and designing new balancing controller. The proposed criteria use dynamically estimate battery states to more accurately reflect the non-uniformity and this increases the pack capacity significantly compared to the traditional balancing criterion. The balancing controller improves the balancing speed and shortens the balancing time in the fast charging process. These contributions have been verified by hardware test or simulation with different battery types.