A battery module for use in a battery system is coupled with other battery modules in the battery system in a daisy-chain configuration. And, the battery module communicates with the other battery modules through a daisy chain according to a communication interface protocol which has a predetermined number of clock pulses. The battery module includes a battery unit and a battery control circuit. When the battery module operates in a bottom mode, the battery control circuit generates an upstream clock output signal which includes the predetermined number of clock pulses plus a number of inserted clock pulses, to compensate a clock difference caused by a propagation delay of the daisy chain, such that the battery module is able to synchronously receive a downstream data signal transmitted from a target module via the daisy chain as the battery module is transmitting an upstream clock output signal.