Battery management systems and methods, and open cell detection systems

A method, comprising:

• enabling a balance unit in a battery management system for a first time period, wherein said balance unit is coupled to a first battery unit;
• disabling said balance unit for a second time period following said first time period;
• receiving, using an under-voltage comparison unit, a first voltage between a first terminal and a second terminal in a third time period following said second time period, wherein said first terminal is coupled to a positive electrode of said first battery unit, and wherein said second terminal is coupled to a negative electrode of said first battery unit;
• comparing, using said under-voltage comparison unit, said first voltage with a first open cell threshold to output a first comparison result;
• receiving, using an over-voltage comparison unit, a second voltage between a third terminal and a fourth terminal in said third time period, wherein said third terminal is coupled to a positive electrode of a second battery unit, wherein said fourth terminal is coupled to a negative electrode of said second battery unit and said positive electrode of said first battery unit, and wherein said second battery unit is coupled in series with and adjacent to said first battery unit;
• comparing, using said over-voltage comparison unit, said second voltage with a second open cell threshold to output a second comparison result;
• and
• determining, using a judging unit, whether a connection between said first battery unit and said battery management system is inoperative based on said first comparison result and said second comparison result.

An open cell detection system, comprising:

• a first battery unit;
• a second battery unit coupled in series with and adjacent to said first battery unit;
• and
• a battery management system, coupled to said first and second battery units, and comprising:
• a balance unit, coupled to said first battery unit, and configured to be enabled for a first time period and disabled for a second time period following said first time period;
• an under-voltage comparison unit, coupled to said balance unit, and configured to receive a first voltage between a first terminal and a second terminal in a third time period following said second time period, and also configured to compare said first voltage with a first open cell threshold to output a first comparison result, wherein said first terminal is coupled to a positive electrode of said first battery unit, and wherein said second terminal is coupled to a negative electrode of said first battery unit;
• an over-voltage comparison unit, coupled to said second battery unit, and configured to receive a second voltage between a third terminal and a fourth terminal in said third time period, and also configured to compare said second voltage with a second open cell threshold to output a second comparison result, wherein said third terminal is coupled to a positive electrode of said second battery unit, and wherein said fourth terminal is coupled to a negative electrode of said second battery unit and to said positive electrode of said first battery unit;
• and
• a judging unit, coupled to said under-voltage and over-voltage comparison units, and configured to determine whether a connection between said first battery unit and a battery management system is inoperative based on said first comparison result and said second comparison result.