A charging method for charging a plurality of batteries (B1 to Bn) of a battery module, wherein the batteries (B1 to Bn) are connected in series with each other, and the charging method comprises: obtaining a charging voltage value of the battery module, wherein the charging voltage value is a voltage value used for charging the batteries (B1 to Bn),; obtaining a maximum voltage value (VMAX) and a minimum voltage value (Vmin) in a plurality of battery voltage values of the batteries (B1 to Bn) according to a relative state of charge (RSOC) of the battery module during a charging process; and obtaining a difference value (ΔV) between the maximum voltage value (VMAX) and the minimum voltage value (Vmin); characterized by obtaining a taper voltage value of the battery module, wherein the taper voltage value is a set voltage value for determining whether the batteries (B1 to Bn) reach a charging saturation state; adjusting both the charging voltage value and the taper voltage value by performing a subtraction operation, wherein obtaining the taper voltage value comprises: detecting the RSOC of the battery module; and in response to that a 100% RSOC is detected, using a detected voltage value of the battery module corresponding to the 100% RSOC as the taper voltage value, and wherein the subtraction operation comprises: subtracting the difference value (ΔV) from the charging voltage value to obtain an adjusted charging voltage value; and subtracting the difference value (ΔV) from the taper voltage value to obtain an adjusted taper voltage value. obtaining a charging voltage value of the battery module, wherein the charging voltage value is a voltage value used for charging the batteries (B1 to Bn),; obtaining a maximum voltage value (VMAX) and a minimum voltage value (Vmin) in a plurality of battery voltage values of the batteries (B1 to Bn) according to a relative state of charge (RSOC) of the battery module during a charging process; and obtaining a difference value (ΔV) between the maximum voltage value (VMAX) and the minimum voltage value (Vmin); characterized by obtaining a taper voltage value of the battery module, wherein the taper voltage value is a set voltage value for determining whether the batteries (B1 to Bn) reach a charging saturation state; adjusting both the charging voltage value and the taper voltage value by performing a subtraction operation, wherein obtaining the taper voltage value comprises: detecting the RSOC of the battery module; and in response to that a 100% RSOC is detected, using a detected voltage value of the battery module corresponding to the 100% RSOC as the taper voltage value, and detecting the RSOC of the battery module; and in response to that a 100% RSOC is detected, using a detected voltage value of the battery module corresponding to the 100% RSOC as the taper voltage value, and wherein the subtraction operation comprises: subtracting the difference value (ΔV) from the charging voltage value to obtain an adjusted charging voltage value; and subtracting the difference value (ΔV) from the taper voltage value to obtain an adjusted taper voltage value. subtracting the difference value (ΔV) from the charging voltage value to obtain an adjusted charging voltage value; and subtracting the difference value (ΔV) from the taper voltage value to obtain an adjusted taper voltage value.