A Comparison of the Effects of Charging Strategies on Lithium-ion Cell Performance in High Temperature Environments

In many parts of the developing world, portable, rechargeable lithium-ion battery packs are being used to provide energy in areas where traditional solutions, such as micro-grids are not viable. This study provides a comparison of the effects of three charging regimes, designed to maximise either stored energy, cycle life or charge speed, on the performance of a batch of lithium-ion cells, when cycled at elevated temperature. The results show that by reducing the voltage stresses on the cell, cycle degradation can be reduced by two-thirds, thus resulting in much increased cell lifetime; this may be achieved whilst only reducing energy storage capability by around 15%. Further, it is demonstrated that significant increases in charge speed are possible without any appreciable loss in stored energy and only a modest increase in degradation over the lifetime of the cell.