Method for evaluating consistency of battery pack and strategy for balancing battery pack

A strategy for balancing a battery pack, comprises:

• obtaining an initial rated capacity and an initial dischargeable electric quantity of each cell in an unused battery pack after a charge and discharge cycle of the battery pack;
• generating a first data diagram for every cells of the battery pack based upon the initial rated capacity and the initial dischargeable electric quantity of each cell;
• after using the battery pack for a period of time, obtaining a real rated capacity and a real dischargeable electric quantity of each cell in the battery pack;
• generating a second data diagram for every cells of the battery pack based upon the real rated capacity and the real dischargeable electric quantity of each cell;
• obtaining a first information of key cells in the first data diagram;
• defining an initial cell distribution region on the first data diagram according to the first information by processing the first data diagram;
• calculating a first area of the initial cell distribution region;
• obtaining a second information of the key cells in the second data diagram;
• defining a real cell distribution region on the second data diagram according to the second information by processing the second data diagram;
• calculating a second area of the real cell distribution region;
• judging whether the second area of the real cell distribution region is consistent with the first area of the initial cell distribution region;
• and
• when the second area of the real cell distribution region is not consistent with the first area of the initial cell distribution region, balancing the battery pack until the second area of the real cell distribution region is consistent with the first area of the initial cell distribution region.