Abstract: A battery system for monitoring a state of a battery subpack may be provided. The battery system may include a battery unit, a positive contactor having a primary positive contactor electrically connected to a positive terminal of the battery unit, and an auxiliary positive contactor including a common (COM) pin, a normally-closed (NC) pin, and a normally-open (NO) pin, a negative contactor electrically connected to a negative terminal of the battery unit, a microprocessor configured to control the positive and negative contactors, a COM control circuit configured to provide an electrical signal to the COM pin, an NC sensing circuit configured to monitor an electrical signal from the NC pin, and an NO sensing circuit configured to monitor an electrical signal from the NO pin. The microprocessor may determine a state of the battery system based on information about the electrical signals from the NC pin and the NO pin.

Abstract: A battery system for balancing battery subpacks may be provided. The battery system may include a plurality of battery subpacks and a master microprocessor. Each of the battery subpacks may include a battery module, a primary positive contactor, an auxiliary positive contactor, a negative contactor, and a subpack microprocessor configured to open and close the primary positive contactor, the auxiliary positive contactor, and the negative contactor. The master microprocessor may be in electrical communication with the subpack microprocessor of each of the battery subpacks. The master microprocessor may be configured to receive information about a voltage value of the battery module of each of the battery subpacks, and sort the plurality of battery subpacks according to the voltage value of the battery subpacks.