The invention discloses a battery equalizing device used for equalizing multiple battery units in a
battery pack by utilizing an equalizing resistance, which comprises a controller, a resistance switching circuit and the equalizing resistance, wherein the resistance switching circuit is used for connecting the battery units specified by the equalizing resistance and the controller in parallel under the control of the controller; and the controller is used for collecting the
voltage value of each battery unit in the multiple battery units, determining the residual
electricity quantity of each battery unit according to the collected
voltage and controlling the resistance switching circuit to connect the equalizing resistance with the battery unit in parallel under the circumstance that one battery unit meets the switching conditions, wherein the switching condition is as follows: the residual
electricity quantity of the battery unit is higher than the specified value of the average residual
electricity quantity of the multiple battery units. The battery equalizing device can intelligently equalize the battery units, effectively reduce the difference between the battery units and cansave the volume and the cost of equipment.