A battery management system, which is applied to an energy storage power station, wherein the energy storage power station comprises a plurality of battery packs electrically connected, each of the plurality of battery pack comprises a plurality of battery units electrically connected, and the battery management system comprises: a plurality of cell supervision circuit, CSC, groups corresponding to the plurality of battery packs respectively, wherein CSCs in each CSC group are connected to battery units in each battery pack respectively, and each CSC is configured to acquire battery cell state data; a plurality of slave battery management units, SBMU, corresponding to the plurality of CSC groups respectively, wherein each of the plurality of SBMUs is connected to each CSC in one CSC group respectively, and the plurality of SBMUs are configured to control the plurality of battery packs based at least on the battery cell state data and generate reported data of the plurality of battery packs; a master battery management unit, MBMU; and an insulation monitoring module IMM; wherein the MBMU is connected to each SBMU and the IMM; the IMM is further connected to the plurality of battery packs and is configured to sample voltage values of the plurality of battery packs, and calculate insulation resistance values of the plurality of battery packs according to the voltage values; the MBMU is configured to interact with at least one device external to the battery management system according to the reported data, characterized in that the MBMU is further configured to analyze the insulation resistance values of the plurality of battery packs to obtain an insulation detection result of the plurality of battery packs, and further configured to perform an measure on the external device when the insulation detection result is that there is an insulation fault; wherein the measure corresponds to the insulation fault. a plurality of cell supervision circuit, CSC, groups corresponding to the plurality of battery packs respectively, wherein CSCs in each CSC group are connected to battery units in each battery pack respectively, and each CSC is configured to acquire battery cell state data; a plurality of slave battery management units, SBMU, corresponding to the plurality of CSC groups respectively, wherein each of the plurality of SBMUs is connected to each CSC in one CSC group respectively, and the plurality of SBMUs are configured to control the plurality of battery packs based at least on the battery cell state data and generate reported data of the plurality of battery packs; a master battery management unit, MBMU; and an insulation monitoring module IMM; wherein the MBMU is connected to each SBMU and the IMM; the IMM is further connected to the plurality of battery packs and is configured to sample voltage values of the plurality of battery packs, and calculate insulation resistance values of the plurality of battery packs according to the voltage values; the MBMU is configured to interact with at least one device external to the battery management system according to the reported data, characterized in that the MBMU is further configured to analyze the insulation resistance values of the plurality of battery packs to obtain an insulation detection result of the plurality of battery packs, and further configured to perform an measure on the external device when the insulation detection result is that there is an insulation fault; wherein the measure corresponds to the insulation fault.