Motorola Solutions, Inc.
Methods and Apparatus for Detecting Open Circuit Faults in a Battery Pack Containing Parallel Cells

Abstract:

Methods and apparatus for detecting open circuit fault conditions in a battery pack containing parallel cells include providing a first control signal to a close FET in parallel with a resistive element, the resistive element being in series with a first battery cell in a first cell path between the terminals of the battery pack, the first cell path being in parallel with a second cell path including a second battery cell. While the FET is closed, a test load is applied across the terminals and a first voltage measurement is obtained at a test point in the battery pack. The methods include providing a second control signal to open the FET, applying the test load across the terminals, obtaining a second voltage measurement at the test point, and determining whether a difference between the first and second voltage measurements indicates an open circuit fault condition in the battery pack.