The voltage of a single cell of the lithium-ion battery is 3.7V, the capacity is generally around several 10Ah, and in the power storage system such as emergency power supply, cells are connected in parallel and in serial and are used as a large capacity battery pack.
Voltage also drops in the storage battery as the capacity decreases due to discharge.
In addition, in lithium-ion batteries, the collapse of the charge balance for each cell poses a risk of causing a major accident.
In lithium-ion batteries, the control system called BMS (battery management system) or protection circuit normally monitors the state of each cell and controls the balance between cells.
Lithium-ion batteries are superior rechargeable batteries, but advanced control is required for balancing per cell and charge control.
For this reason, as a power source for charging, it is common to develop customized products or use an expensive and high performative AC-DC switching power supply.
Performing constant voltage constant current chargingthat is the most appropriate for the battery pack not only optimizes battery performance but also elicits an effect on longer lifespan and safety.