BATTERY MONITORING SYSTEM FOR MEASURING CARBON DIOXIDE TO DETECT IMBALANCE IN A GROUP OF PARALLEL LITHIUM-ION BATTERY CELLS

A battery monitoring system includes a carbon dioxide sensing system configured to selectively measure carbon dioxide concentrations within a plurality of battery cells, respectively, that are connected in parallel. A controller is configured to detect cathode overpotential in the plurality of battery cells in response to the measured carbon dioxide concentrations of the plurality of battery cells.