Abstract: A battery is rapidly charged utilizing a bipolar waveform (21, 22). The voltage, current, duration and frequency parameters of the bipolar waveform are selected to perform a number of actions: enhancing the mixing action at the battery electrodes; measuring the battery's capacitance, condition, and level of impedance; modifying the mass transport process inside the battery; and reducing the concentration of the diffusion layer, the polarization concentration, and the overpotential. This reduces internal heat generation by providing for more efficient ion transport, reduced concentration gradients, and increased diffusion rates and intercalation speeds. A bipolar waveform can be in the form of sine waves, or other wave shapes. A charge pulse (11) is preferably followed by a small technical rest period (12), after which a discharge pulse (13) is applied followed, in turn, by a rest period (14). The bipolar waveform (21) is superimposed on one or more of the above.

Abstract: A method and an apparatus (10) for equalizing the state of charge among a plurality of series-connected batteries (B1-BN). A module (12A-12N) is connected in parallel with each of the batteries (B1-BN), respectively. Each module (12A-12N) contains a voltage divider circuit (40) so that the voltage across a battery may be measured to determine the state of charge, and a circuit (43) which selectively shunts charging current around a battery or applies a discharging current to a battery. A charging transistor (30) applies a charging current to the series of batteries (B1-BN) and, depending upon the state of charge of each battery, a portion of the charging current may be shunted around the battery by its associated module (12) so as to prevent overcharging of the battery.