At present, the following methods are important to realize the equalization of each single battery in the series battery pack.
1. Add a parallel equalization circuit to each single battery of the battery pack to achieve the purpose of shunting. In this mode, when a battery reaches full charge first, the equalization device can prevent it from overcharging and convert the excess energy into heat, and continue to charge the undercharged battery. This method is simple, but it will cause energy loss and is not suitable for fast charging systems.
2. Before charging, each cell is discharged to the same level through the same load one by one, and then constant current charging is performed to ensure a more accurate equilibrium state between each cell. However, for battery packs, due to 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 discharging, a new imbalance will appear during the charging process.
3. The single cells in the battery pack are tested and charged uniformly on time, in sequence, and individually. When charging the battery pack, it can be ensured that each battery in the battery pack will not be overcharged or over-discharged, 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 the switch components, the extra current flows into the battery with a relatively low voltage to achieve the purpose of equalizing charging. This method is more efficient, but the control is more complicated.
5. Take the voltage parameters of each battery as the object of balance to restore the same voltage of each battery. During equalizing charging, the capacitor is alternately connected to two adjacent batteries through the control switch, accepts the charging of the high-voltage battery, and then discharges to the low-voltage battery until the voltages of the two batteries tend to be the same.
This kind of equalization method better solves the problem of battery pack voltage imbalance, but this method is mainly used in occasions with a small number of batteries
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