Patent ID: 8796992
Filing Date: 2014-08-05
Classification: H01M,H02J,Y02B,Y02E,Y02P

Abstract:
1. A basic unit of lithium-ion battery pack, comprising: a) at least two serially-connected lithium-ion cells; b) at least one lithium-ion cell for balance; c) controllable switches with the same number as the at least two serially-connected lithium-ion cells; d) a drive module for the controllable switches; e) a voltage detection module for detecting a voltage at two ends of each of the at least two serially-connected lithium-ion cells; and f) a controller; wherein the at least one lithium-ion cell for balance is configured to be selectively connected in parallel to one of the at least two serially-connected lithium-ion cells that has a highest voltage among the at least two serially-connected lithium-ion cells during a charging operation of the basic unit of lithium-ion battery pack; wherein the at least one lithium-ion cell for balance is configured to be selectively connected in parallel to one of the at least two serially-connected lithium-ion cells that has a lowest voltage among the at least two serially-connected lithium-ion cells during a discharging operation of the basic unit of lithium-ion battery pack; the controllable switches respectively control the turn on/off of the parallel connection between the at least one lithium-ion cell for balance and one of the at least two serially-connected lithium-ion cells independently at each time to conduct charging or discharging; and the drive module for the controllable switches and the voltage detection module are connected to the controller.