Battery charging device and a battery charging method

The present invention provides a battery charging apparatus, comprising: a charging power supply connected to the target cell, target battery charge; unit voltage recording, the recording power to the target charging voltage of the battery charging; calculation processing unit, in accordance with the received acquisition instruction, obtaining preset time interval from the charging voltage of the reference voltage, and correcting the rate of change of the reference voltage curve of a preset algorithm, to obtain correction curves, and calculate the slope of the correction curve; comparing unit, and setting the value of the slope is comparison, if the slope is less than the set value, it sends an instruction to the output control unit; output control unit, upon receiving the instruction, the charging voltage drops below a preset voltage value. The present invention further provides a method for charging a battery. , Can be corrected by the voltage change rate of the process aspect of the present invention to avoid misjudgment charge voltage change rate and erroneous operation, and can reduce water loss of the battery, the battery life.