Abstract: A method of charging a rechargeable battery which comprises charging the battery with a charging current; sampling conditions of the battery during charging to recognize potential adverse conditions within the battery; interrupting the charging current periodically to create current-free periods and sampling an open circuit voltage of the battery during each current-free period to identify potential overcharge conditions in the battery; lowering the charging current if any adverse conditions are identified and continuing charging with the charging current if adverse charging conditions are not identified; and terminating charging when a predetermined value is recognized. The method of charging nickel-metal hydride and nickel-cadmium batteries is based on switching charging current as soon as temperature related battery open circuit voltage reaches the first predetermined value, tapering current and continuing charging up to terminating point.

Abstract: A method of charging a rechargeable battery which comprises charging the battery with a charging current; sampling a charging voltage of the battery during charging to recognize potential adverse conditions within the battery; interrupting the charging current periodically to create current-free periods and sampling an open circuit voltage of the battery at a plurality of points during each current-free period to identify potential overcharge conditions in the battery; lowering the charging current if any of the above-identified adverse conditions are identified and continuing charging with the charging current if the potential adverse charging condition is not identified; and terminating charging when a negative slope on a chemical polarization versus time curve is identified below a pre-determined minimum level.

Abstract: A method of charging a rechargeable lithium battery which comprises charging the battery with a charging current; sampling a charging voltage of the battery during charging to recognize potential electrolyte decomposition; interrupting the charging current periodically to create current-free periods and sampling an open circuit voltage of the battery at a plurality of points during each current-free period to identify potential shunting and unequal states of charge among individual cells of the battery; lowering the charging current if any of the above-identified adverse conditions are identified and continuing charging with the charging current if the potential adverse charging condition is not identified; and terminating charging when the charging current is lowered below a pre-determined minimum level.

Abstract: An apparatus and method of recognizing a shunt caused by formation of dendrites in a rechargeable lithium battery which comprises charging the battery with a charging current, sampling the charging current voltage of the battery at pre-determined time intervals in order to identify one or more point indicating onset of shunting, and terminating charging if the shunt or dendrite is indicated. If a shunt is not recognized charging is continued. Dendrite formation or the beginning of shunting due to such formation is indicated by any one of the following conditions: a negative gradient in sampled voltage values; a negative gradient in sampled steady open circuit values; and a negative gradient in the chemical polarization voltage values which may be calculated by sampling both the open circuit voltage soon after current interruption and steady open circuit voltages during a plurality of currentless phases.