What are the methods of balanced charging for lithium-ion batteries?

At present, there are several important methods to charge each single battery in series.

1. Attach a parallel equalization circuit to each single cell of the battery pack to achieve the purpose of shunt. In this mode, when a battery first reaches the Wally, the balancing device can prevent it from being overcharged and convert excess energy into heat energy, and continue to charge the battery that is not fully charged. This method is simple, but it will bring energy loss and is not suitable for fast charging system.

2. Before charging, each monomer is discharged to the same level through the same load one by one, and then charged with constant current, so as to ensure a more accurate equilibrium state among the monomers. However, due to the physical differences between individuals, it is difficult to achieve the same ideal effect after deep discharge of each monomer. Even if the same effect is achieved after discharge, new imbalance will appear during charging.

3. Test and uniformly charge the single batteries in the battery pack on time, in sequence and independently. When charging the battery pack, it can ensure that each battery in the battery pack will not be overcharged or overdischarged, thus ensuring that each battery in the battery pack is in a normal working state.

4. Using the time-sharing principle, through the control and switching of switch components, extra current flows into the battery with relatively low voltage to achieve the purpose of balanced charging. This method is efficient, but the control is complicated.

5. Take the voltage parameters of each battery as the balancing object, so that the voltages of each battery can be restored to be consistent. During balanced charging, the capacitor is alternately connected with two adjacent batteries through the control switch, receiving the charging from the high-voltage battery, and then discharging to the low-voltage battery until the voltages of the two batteries tend to be consistent.

This balancing method can solve the problem of unbalanced battery voltage, but it is important to use it in the situation where the number of batteries is small.

6. The whole system is controlled by single chip microcomputer, and each battery has an independent set of modules. The module manages the charging of each single battery according to the set program, and automatically disconnects after the charging is completed.