A process and system for measuring internal faults in an electrochemical cell is provided. The process for detecting an internal fault in an electrochemical cell includes measuring a voltage difference or a rate of change in voltage difference between a common terminal of a first electrochemical cell and a second electrochemical cell. The first electrochemical cell or second electrochemical cell is accepted based on the measuring, or first electrochemical cell or second electrochemical cell is rejected based on the measure of the internal fault of the electrochemical cell.