Circuit for cells - current monitoring a multicell battery during the battery charge

摘要

A circuit (M) to monitor and protect individual cells (12-1 . . . 12-n) of a multi-cell battery (10) from over-charge and acquire data to be used to determine various characteristics of the cell state-of-health is connected to each individual cell (12) of a multi-cell battery as the battery is being charged. The circuit includes a portion (Q1-R5) to bypass charging current from the cell, this portion being variably pre-settable to bypass current above a desired high voltage (V-By) limit for the cell. As the battery is being charged, the bypass circuit will shunt current around a cell when the preset high voltage level is exceeded, thus preventing any damage to the cell. The circuit (Q2) can be operated to produce a pulse of current and the change in voltage of the monitored cell in response to the change in current, dV/dI, can be used to determine the cell internal resistance. The cell polarization resistance also can be determined. The data acquired can be used to determine factors relating to the cell state of charge (SOC) and its state of health. A programmable controller (C) controls all of the circuits and also acquires the data produced by the circuits.