Battery charging method and device thereof

A battery charging method including the steps of:

• (a) supplying a charging current into a battery module having a plurality of cell blocks for charging;
• (b) detecting the terminal voltages of said cell blocks;
• (c) continuously charging over a first preset time period when one of said terminal voltages exceeds a first threshold;
• (c′) determining whether or not one of said terminal voltages of said cell blocks exceeds a second threshold, and performing step (d) if one of said terminal voltages of said cell blocks exceeds a second threshold, otherwise, performing step (e);
• (d) performing an over voltage protection;
• (e) reducing the charging current and continuously supplying reduce charging current over a second preset time period;
• and
• (f) determining whether or not said cell-blocks are fully charged, and stopping charging if said cell-blocks are determined being fully charged;
• otherwise, performing step (a) or step (c′).

A battery charging device, applied for a battery module having a plurality of cell blocks, said battery charging device comprising:

• a charging module for supplying a charging current into said cell blocks;
• an over voltage protection module for providing an over voltage protection function to said cell blocks;
• and
• a control module for detecting the terminal voltages of said cell blocks, when one of said terminal voltages exceeds a first threshold, said control module continuously supplying said charging current into said battery module over a first preset time period, and then determining whether or not one of said terminal voltages of said cell blocks exceeds a second threshold.