Equalization charging and principle analysis of lithium battery pack protection board

Lithium battery pack protection board equalization charging methods commonly used lithium battery pack equalization charging techniques include constant shunt resistance equalization charging, on-off shunt resistance equalization charging, uniform battery voltage equalization charging, switched capacitor equalization charging, step-down converter equalization charging, and inductance Equalizing charging, etc. When charging a group of lithium batteries in series, ensure that each battery is charged in a balanced manner, otherwise the performance and life of the entire group of batteries will be affected during use. 1. Attach a parallel equalization circuit to each single cell of the lithium 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 energy to continuously charge the battery that is not overflowing. This method is simple, but it will cause energy loss and is not suitable for fast charging systems. 2. Before charging, each monomer 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 the individual monomers. 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. Test and averagely charge the single cells in the lithium battery pack on time, in order, and individually. When charging the lithium battery pack, it can be ensured that each lithium battery in the battery pack will not be overcharged or overdischarged, thus ensuring that each battery in the lithium 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 balanced 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 handles the problem of battery pack voltage imbalance, but this method is urgently used in occasions with a small number of batteries. 6. The entire system is controlled by a single-chip microcomputer, and the single battery has an independent set of modules. The module manages the charging of each single battery separately according to the set procedure, and automatically disconnects after the charging is completed. This method is relatively simple, but it will increase the cost greatly when the number of single cells is large, and it is also not conducive to the reduction of the system volume. Lithium battery pack protection board equalization charging principle The number of single-cell lithium battery protection chips is determined according to the number of lithium battery pack batteries, and they are used in series to protect the corresponding single-cell lithium battery from charging and discharging, overcurrent, and short-circuit conditions. While charging and protecting, the system uses the protection chip to control the on and off of the shunt discharge branch switch to achieve balanced charging. This method is different from the traditional method of achieving balanced charging at the charger end, and reduces the design of the lithium battery pack charger. The cost of use. The lithium battery pack is made up of multiple single lithium batteries in series. Due to the differences of the monomers, the inconsistent rise of terminal voltage during series charging will cause the problems of overcharging of some monomers and insufficient charging of some monomers. All batteries are connected in parallel during equalizing charging, and connected in series during regular charging and power consumption. During equalizing charging, all the batteries have the same parallel voltage, which realizes the forced equalization of each battery. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Analysis of the use and advantages of 18650 lithium batteries