Commonly used lithium-ion battery pack equalization charging technologies include constant shunt resistance equalization charging, on-off shunt resistance equalizing charging, average battery voltage equalizing charging, switched capacitor equalizing charging, step-down converter equalizing charging, inductor equalizing charging, etc. When charging a group of lithium-ion batteries in series, ensure that each battery is charged equally, otherwise the performance and life of the entire group of batteries will be affected during use.
1. Add a parallel equalization circuit to each single cell of the lithium-ion battery pack to achieve the purpose of shunt. In this mode, when a battery reaches full charge first, the equalizer prevents it from overcharging and converts the excess energy into heat, continuing to charge the battery that is not fully charged. This method is simple, but it will cause energy loss and is not suitable for fast charging systems.
2. Before charging, discharge each cell one by one through the same load to the same level, and then perform constant current charging to ensure a more accurate equilibrium state between each cell. However, for the battery pack, due to the physical differences between individuals, it is difficult to achieve a completely consistent ideal effect after deep discharge of each cell. Even if the same effect is achieved after discharge, new imbalances will appear during charging.
3. Detect and uniformly charge the single cells in the lithium-ion battery pack on time, in sequence, and individually. When charging the lithium-ion battery pack, it can ensure that each lithium-ion battery in the battery pack will not be overcharged or overdischarged, thus ensuring that each battery in the lithium-ion battery pack is in normal operation. state.
4. Using the time-sharing principle, through the control and switching of the switch components, the extra current flows into the battery with a relatively low voltage to achieve the purpose of balanced charging. This method is more efficient, but the control is more complicated.
5. Take the voltage parameters of each battery as the balance object to restore the voltage of each battery to the same. During balanced charging, the capacitor is alternately connected to two adjacent batteries through the control switch, accepts the charge of the high-voltage battery, and then discharges the low-voltage battery until the voltages of the two batteries tend to be the same.