An energy storage module (1, 1a, 1b, 1c, 1d, 1e) includes a bus connection part (2), a battery pack (3), a capacitor (Cb) and a series compensation DC conversion device (4). A first conduction terminal (41) of the series compensation DC conversion device (4) is electrically connected with a positive bus connection terminal (21) and a negative bus connection terminal (22) of the bus connection part (2), or the first conduction terminal (41) is connected with a battery positive terminal (31) and a battery negative terminal (32) of the battery pack. A second conduction terminal (42) of the series compensation DC conversion device (4) is electrically connected with two terminals of the capacitor (Cb). A four-quadrant DC/DC converter (44, 44a) of the series compensation DC conversion device (4) controls the capacitor (Cb) to generate a compensation voltage (Vcb) to compensate a voltage between the two terminals of the battery pack, or the four-quadrant DC/DC converter (44, 44a) adjusts a current flowing through the battery pack to a set value.