A battery management system comprising: a charge control switch (SW1) and a discharge control switch (SW2) disposed in a path through which a charging current or a discharging current flows, between a plurality of pack terminals and a battery module ; and a controller configured to: detect a cell voltage of each of a plurality of cells included in the battery module, detect a charging current flowing between the plurality of pack terminals and the battery module, determine an overvoltage state of the battery module based on presence or absence of the charging current and the cell voltages of the cells, characterised in that the controller is arranged to: turn off the charge control switch when the battery module is in the overvoltage state, in which a maximum cell voltage among the cell voltages of the cells is equal to or greater than a first threshold value in a state where the charging current flows, maintain current states of the charge control switch and the discharge control switch even when maximum cell voltage is equal to or greater than the first threshold value in a state in which the charging current does not flow, turn off the discharge control switch when the maximum cell voltage is equal to or higher than a second threshold value in a state where the charging current flows, and the second threshold value is higher than the first threshold value. a charge control switch (SW1) and a discharge control switch (SW2) disposed in a path through which a charging current or a discharging current flows, between a plurality of pack terminals and a battery module ; and a controller configured to: detect a cell voltage of each of a plurality of cells included in the battery module, detect a charging current flowing between the plurality of pack terminals and the battery module, determine an overvoltage state of the battery module based on presence or absence of the charging current and the cell voltages of the cells, detect a cell voltage of each of a plurality of cells included in the battery module, detect a charging current flowing between the plurality of pack terminals and the battery module, determine an overvoltage state of the battery module based on presence or absence of the charging current and the cell voltages of the cells, characterised in that the controller is arranged to: turn off the charge control switch when the battery module is in the overvoltage state, in which a maximum cell voltage among the cell voltages of the cells is equal to or greater than a first threshold value in a state where the charging current flows, maintain current states of the charge control switch and the discharge control switch even when maximum cell voltage is equal to or greater than the first threshold value in a state in which the charging current does not flow, turn off the discharge control switch when the maximum cell voltage is equal to or higher than a second threshold value in a state where the charging current flows, and the second threshold value is higher than the first threshold value. turn off the charge control switch when the battery module is in the overvoltage state, in which a maximum cell voltage among the cell voltages of the cells is equal to or greater than a first threshold value in a state where the charging current flows, maintain current states of the charge control switch and the discharge control switch even when maximum cell voltage is equal to or greater than the first threshold value in a state in which the charging current does not flow, turn off the discharge control switch when the maximum cell voltage is equal to or higher than a second threshold value in a state where the charging current flows, and the second threshold value is higher than the first threshold value. <EOS>