A battery system for an electric vehicle includes at least one battery module and a management module. The battery module includes a plurality of battery cells, and an outer casing which defines therein an accommodation space for accommodation of the battery cells, and which is configured to permit a thermal management fluid to flow through the accommodation space to thereby provide thermal management to the battery cells. The management module includes at least one sensing unit and is coupled to the battery module to permit the sensing unit to be submerged in the thermal management fluid for collecting information of the battery cells and the thermal management fluid.