Patent ID: 8717035
Filing Date: 2014-05-06
Classification: G01R,H01M,Y02E

Abstract:
1. A method for detecting an open cell tap condition in a battery pack having a plurality of battery cells and operably coupled to a battery charger, comprising: selecting a given inter-cell connection from amongst two or more inter-cell connections that are configured to measure voltage between the plurality of battery cells; applying, from a positive supply terminal of the battery pack, a detection voltage across an electrical impedance that is coupled to a measurement node, wherein the positive supply terminal of the battery pack is connectable to the electrical impedance, and wherein the measurement node is coupled by the given inter-cell connection to a node disposed between serially coupled battery cells; measuring, by the battery charger, a voltage at the measurement node; wherein the steps of selecting, applying and measuring are enabled by closure of only one switch of the battery charger, wherein the one switch connects the positive supply terminal of the battery pack to the measurement node; detecting, by the battery charger, a break in the given inter-cell connection when the voltage measured at the measurement node is substantially equal to the detection voltage; opening the one switch; measuring, by the battery charger, the voltage at the measurement node while the one switch is open; and determining, by the battery charger, that one of the cells of the battery pack is overcharging when the voltage measured at the measurement node is greater than a threshold voltage.