High voltage lithium battery charging method -Lithium - Ion Battery Equipment

High voltage lithium battery charging method -Lithium - Ion Battery Equipment

1. Ordinary series charging

At present, the charging of lithium-ion battery packs is generally performed by series charging, which is mainly because the series charging method is simple in structure, low in cost, and relatively easy to implement. However, due to the differences in capacity, internal resistance, attenuation characteristics, self-discharge and other performances between single lithium-ion batteries, when lithium-ion battery packs are charged in series, the single lithium-ion battery with the smallest capacity in the battery pack will It is fully charged first, and at this time, other batteries are not fully charged. If the series charging is continued, the fully charged single lithium-ion battery may be overcharged.(Lithium - Ion Battery Equipment)

Overcharging of a lithium-ion battery will seriously damage the performance of the battery, and may even cause an explosion and cause personal injury. Therefore, in order to prevent overcharging of a single lithium-ion battery, a lithium-ion battery pack is generally equipped with a battery management system. The management system protects each single lithium-ion battery from overcharging. When charging in series, if the voltage of a single lithium-ion battery reaches the overcharge protection voltage, the battery management system will cut off the entire series charging circuit and stop charging to prevent the single battery from being overcharged, which will cause other problems. Lithium-ion batteries cannot be fully charged.

2. The battery management system and the charger coordinate with series charging

The battery management system is the device that has the most comprehensive understanding of the performance and status of the battery. Therefore, establishing a connection between the battery management system and the charger can enable the charger to understand the information of the battery in real time, so as to solve the problem of battery charging more effectively. There are some problems.

The principle of the battery management system and the charger coordinating with the charging mode is: the battery management system monitors the current state of the battery (such as temperature, single battery voltage, battery operating current, consistency and temperature rise, etc.), and uses these parameters. The maximum allowable charging current of the current battery is estimated; during the charging process, the battery management system and the charger are connected through a communication line to realize data sharing.

3. Parallel charging

In order to solve the problem of overcharge and undercharge of some single cells in the battery pack, a parallel charging method has been developed.

However, the parallel charging method needs to use multiple low-voltage, high-current charging power sources to charge each single battery, which has defects such as high charging power source cost, low reliability, low charging efficiency, and thick connecting wire diameter. The range uses this charging method.

4. Series high current charging plus small current parallel charging

Since the above three charging methods all have certain problems, a charging method that is most suitable for high-voltage battery packs, especially electric vehicle battery packs, has been developed. Current-limited parallel low-current charging mode.



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