BATTERY MANAGEMENT CIRCUIT AND METHOD FOR CONTROLLING THE IN-CIRCUIT CHARGE AND DISCHARGE OF SERIES-CONNECTED RECHARGEABLE ELECTROCHEMICAL CELLS

摘要

The invention is a battery management circuit and corresponding method for controlling the in-circuit charge and discharge of series-connected electrochemical cells. The invention finds particular application in the field of devices powered by rechargeable alkaline manganese dioxide cells, but also finds application in other types of chargers, devices and electrochemical cells or batteries. The battery management circuit of the invention monitors the voltage of individual series-connected cells that power a device. The circuit terminates discharge of all cells as soon as the voltage of one of the cells drops to a predetermined level. During in-circuit charging of the cells, the battery management circuit monitors the voltage of individual series-connected cells as they are being recharged, and terminates the provision of charging current to all cells as soon as one of the cells attains a sufficiently high predetermined voltage. Appropriate termination of the provision of charging current to the cells combined with the appropriate termination of the provision of discharging current from the cells, permits the cells to provide a maximum number of discharge/charge cycles. The invention permits rechargeable cells to provide greater cumulative coulometric capacity, and reduces the incidence of electrolyte leakage from rechargeable cells. The cells may be contained in a battery pack, or may be mounted directly in a device. Electronic circuitry and software programmable device embodiments of the invention are described.