How to perform balanced charging on lithium-ion batteries.
What is battery balanced charging? Balanced charging refers to the process of balancing the voltage at the battery terminals during battery operation, taking into account individual differences, temperature differences, and other factors that may cause voltage imbalance. It is necessary to increase the charging voltage of the battery pack and activate it to achieve the basic characteristics of each battery in the balanced battery pack. Next, let's talk about how lithium-ion batteries can be charged evenly.
Common balanced charging methods
Common balanced charging techniques include constant shunt resistance balanced charging, on-off shunt resistance balanced charging, average battery voltage balanced charging, power switch capacitor balanced charging, buck converter balanced charging, inductor balanced charging, etc. When charging a combination of lithium-ion batteries in series, it is necessary to ensure that each battery is charged evenly, otherwise it will affect the stability and lifespan of the entire battery pack during operation.
Design method of battery pack protection board with balanced charging function for
lithium-ion battery protection.
Attach a parallel balancing circuit to each individual cell of the lithium-ion battery pack to achieve the purpose of current splitting. In this state, when a battery reaches full charge first, the balancing device can prevent overcharging and convert unnecessary energy into heat energy to continue charging the battery that is not fully charged. This method is simple, but it can cause energy loss and is not very suitable for fast charging systems.
Timely, sequentially, and individually test and uniformly charge the individual cells in the lithium-ion battery pack. When charging a
lithium-ion battery pack, it can be ensured that each lithium-ion battery in the pack will not experience overcharging or overdischarging, thus ensuring that each battery in the lithium-ion battery pack is in a normal working environment. By applying the time-sharing principle and controlling and switching the power switch components, additional current can flow into batteries with relatively high voltage to achieve balanced charging. The efficiency of the method is very high, but the control is very complex.
Before charging, each individual cell is charged and discharged one by one through the same load to the same level, and then constant current charging is performed to ensure a relatively accurate balance state between each cell. However, for battery packs, considering the physical differences between individuals, it is difficult to achieve exactly the same optimal effect after deep discharge of each individual cell. Even if the same effect is achieved after charging and discharging, new imbalances will still occur during the charging process. The voltage parameters of each battery are balanced to restore the normal and consistent voltage of each battery. During balanced charging, capacitors are alternately connected to adjacent batteries through control switches, receiving charging from high-voltage batteries and discharging from low-voltage batteries until the voltage of the two batteries tends to be the same.
