Estimation method for residual charging time of battery

The invention relates to an estimation method for residual charging time of a battery. The estimation method comprises the steps of: obtaining temperature of each battery unit by a temperature sensor arranged on each battery unit of a battery pack; obtaining voltage of each battery units by a sampling circuit; according to the voltage, obtaining the battery load state of the battery pack by a battery control unit; when battery load state value is smaller than a constant-current charging threshold value, calculating the residual charging time by the battery control unit according to the formula (1), otherwise, calculating the residual charging time by the battery control unit according to the formula (2), wherein the constant-current charging threshold is a threshold obtained when a charger converts from larger charging current into stable smaller charging current; and displaying the residual charging time by a display unit. The estimation method for residual charging time of the battery can estimate the residual charging time of the battery pack by utilizing the battery load state, battery temperature and battery capacity according to the charging rules of the battery, so that a battery management system is capable of displaying residual charging time, thus further providing support for application of other related parts.