Compared with high voltage of 300V/400V battery system, 48V battery bank is safer and more reliable in terms of cell balance and BMS protection. E.g., for 48V battery, normally it adopts 14pcs cells in series (NMC) or 16pcs cells (LiFeO4) only. However, for rated voltage of 400V battery, it needs more than 100pcs cells in series. If the cell voltage difference is 0.1V and for 100+pcs cells in series the total voltage difference exceeds 10V, which is huge challenge for the battery BMS and system safety. Also, the battery capacity can’t be expanded easily since the cell balance issue.