  Due to manufacturing variabilities and temperature gradients within an
electric vehicle's battery pack, the capacities of cells in it decrease
differently over time. This reduces the usable capacity of the battery - the
charge levels of one or more cells might be at the minimum threshold while most
of the other cells have residual charge. Active cell balancing (i.e.,
transferring charge among cells) can equalize their charge levels, thereby
increasing the battery pack's usable capacity. But performing balancing means
additional charge transfer, which can result in energy loss and cell aging,
akin to memory aging in storage technologies due to writing. This paper studies
when cell balancing should be optimally triggered to minimize aging while
maintaining the necessary driving capability. In particular, we propose
optimization strategies for cell balancing while minimizing their impact on
aging. By borrowing terminology from the storage domain, we refer to this as
"wear leveling-aware" active balancing.
