US Patent 11302970 Power supply system

A power supply system includes a controller, and a plurality of battery modules. The battery modules are connected in series, according to a gate drive signal from the controller, to provide series connection, and each of the battery modules has a disconnecting device configured to force the battery module to be disconnected from the series connection. The controller is configured to estimate the internal resistance of the battery module disconnected from the series connection by the disconnecting device, from a module voltage of the battery module before the battery module is disconnected from the series connection, a module voltage immediately after the battery module is disconnected, and a module current delivered from the battery module.