Why is a 72 volt lithium battery string always undercharged?

Lithium batteries in electric vehicles are composed of multiple batteries, which raises the question of whether the performance of each battery is consistent. It is possible that the performance of individual batteries may deteriorate after long-term use. There are two ways to resolve this problem. The first is to balance the battery with the balancing method. The second is to replace the batteries that are not working and choose the exact same battery once fully charged. the battery before replacing it, do not overcharge it or use it too much.