The invention provides a
lithium battery pack charging method. According to the
lithium battery pack charging method, the diversity of single cells is gradually reduced by adopting four stages of a constant-current pre-charging mode, a constant-current equalizing charging mode, a constant-
voltage current-reducing charging mode, and a constant-current
trickle charging mode. The relatively poor single
cell can be relatively fully charged, and the relatively good
cell can be discharged in an equalizing manner by controlling the charging time and charging current of the single
cell with a relatively poor performance so as to achieve the effect that the diversity of the single cells is well reduced. The cells can be recovered to a certain degree by stopping charging for a period of time in the
constant voltage charging mode, the
voltage of the relatively-high-
voltage single cell is reduced to a certain degree, so that the charging time can be prolonged for the relatively
low voltage cell, and finally the cell is charged with
trickle with the minimum charging current. This period of the charging time is prolonged so that the relatively
low voltage cell keeps to be changed for a long time. In the whole charging process, the diversity of the single cells is reduced by prolonging the charging time so as to achieve the effect that the cells are relatively fully charged, and the service life of a
battery pack is relatively long.