The method of constant current charging, also known as the constant current charging method, is used during the charging process. This method ensures that the charging current remains constant, although it requires sophisticated automated charging equipment. To keep the charging current from dropping due to the increase in battery terminal voltage, the power supply voltage must be gradually increased. A higher charging current implies a shorter charging time under the maximum allowable charging current of the battery, which is an advantage of this method. However, in the later stages of charging, if the charging current remains unaltered, most of the current is utilized for electrolytic water, resulting in electrolysis and boiling of the electrolyte. This contributes to energy loss and a significant decline in battery capacity. Additionally, this may cause electrode plate deformation, a rise in temperature, and early battery scrapping. As a result, this charging method is seldom used.