Abstract: A rechargeable battery, module or a pack, having different levels of internal resistance that operate at different temperatures are disclosed. In a subfreezing environment, the battery can exhibit high resistance which once operated or activated, generates heat internally to warm up the battery quickly. Once the batter reaches normal operating temperatures, the battery can switch to a low resistance operating mode, thereby delivering superior power and energy despite operating in a very low ambient temperature.

Abstract: A controller in a charging control system controls a charger to heat a battery at a low temperature by pulse charging and discharging up to a desired temperature and then moves to a normal charging mode. The controller calculates an ion concentration of an active material at electrode portions of the battery on the basis of the temperature data and the electric current data obtained, switch the pulse charging and discharging between a charging mode and a discharging mode on the basis of a pulse width when the ion concentration reaches a threshold.