An energy storage system, comprising: multiple battery cells, a subrack, a backplane, and a battery management system, BMS, wherein the subrack comprises a plurality of battery cell slots such that the battery cells are connected to the backplane through the battery cell slots; the backplane is installed in the subrack, and is configured to provide a first power terminal at a position corresponding to each battery cell slot such that a plug-in power terminal is formed by a second power terminal of the battery cell together with the first power terminal; a power circuit, a sampling circuit, and an equalizer circuit are integrated into the backplane such that when the second power terminal is plugged and docked with the first power terminal, the battery cell is connected to the power circuit, the sampling circuit, and the equalizer circuit, wherein the power circuit is configured to connect a current generated by discharge of the battery cells to positive and negative busbars to which the energy storage system in connected, and the sampling circuit and the equalizer circuit are configured to collect parameters of each of the battery cells, and support discharge of each of the battery cells without connection to the positive and negative busbars; the BMS is connected to the backplane for managing the energy storage system, wherein the BMS and the backplane are connected by plugging; wherein: the power circuit includes, for each battery cell, a bypass switch and a branch switch, and the power circuit is configured such that: when the second power terminal is plugged and docked with the first power terminal, the bypass switch is opened and the branch switch is closed; and when the second power terminal is not plugged and docked with the first power terminal or the battery cell fails, the bypass switch is closed and the branch switch is opened. multiple battery cells, a subrack, a backplane, and a battery management system, BMS, wherein the subrack comprises a plurality of battery cell slots such that the battery cells are connected to the backplane through the battery cell slots; the backplane is installed in the subrack, and is configured to provide a first power terminal at a position corresponding to each battery cell slot such that a plug-in power terminal is formed by a second power terminal of the battery cell together with the first power terminal; a power circuit, a sampling circuit, and an equalizer circuit are integrated into the backplane such that when the second power terminal is plugged and docked with the first power terminal, the battery cell is connected to the power circuit, the sampling circuit, and the equalizer circuit, wherein the power circuit is configured to connect a current generated by discharge of the battery cells to positive and negative busbars to which the energy storage system in connected, and the sampling circuit and the equalizer circuit are configured to collect parameters of each of the battery cells, and support discharge of each of the battery cells without connection to the positive and negative busbars; the BMS is connected to the backplane for managing the energy storage system, wherein the BMS and the backplane are connected by plugging; wherein: the power circuit includes, for each battery cell, a bypass switch and a branch switch, and the power circuit is configured such that: when the second power terminal is plugged and docked with the first power terminal, the bypass switch is opened and the branch switch is closed; and when the second power terminal is not plugged and docked with the first power terminal or the battery cell fails, the bypass switch is closed and the branch switch is opened. when the second power terminal is plugged and docked with the first power terminal, the bypass switch is opened and the branch switch is closed; and when the second power terminal is not plugged and docked with the first power terminal or the battery cell fails, the bypass switch is closed and the branch switch is opened.