Safe charging method and apparatus for lithium secondary battery

Abstract

The invention discloses a safe charging method and apparatus for a lithium secondary battery. The charging method comprises the following steps: step S110, obtaining internal actual temperature T<actual> of the lithium ion battery, and calling a corresponding charging mode according to T<actual>; step S120, charging the lithium ion battery according to the charging mode in the step S110; and step S130, finishing charging when the lithium ion battery is charged to reach a rated capacity value. The apparatus comprises a battery pack, a charger, a load, a BMS and a main control unit. The charger is connected with the battery pack; the load is connected with the battery pack; the BMS is connected with the battery pack and the main control unit; and the main control unit is connected with the charger and the load. The safe charging method and apparatus for the lithium secondary battery can satisfy charging in extremely-cold and high-temperature conditions, have a relatively wide charging temperature range, can deal with challenges in harsh environments and severe conditions, and have relatively high safety.

Description

technical field [0001] The invention relates to the technical field of charging lithium ion batteries, in particular to a safe charging method and device for lithium secondary batteries. Background technique [0002] The rapid development of electric vehicles puts forward higher requirements for the charging system. When the electric vehicle is running outdoors, the battery is always in the state of charging and discharging, which requires careful management of the battery with high safety and high reliability. Especially when using lithium-ion batteries with high specific energy, it is necessary not only to ensure the reliable use of lithium-ion batteries under normal temperature conditions, but also to ensure the reliable use of lithium-ion batteries under high-cold and high-temperature conditions to withstand the harsh environment. challenge. [0003] Because lithium batteries are charged under low temperature conditions, lithium crystals are easily precipitated on the n...

AI Technical Summary

Problems solved by technology

[0003] Because lithium batteries are charged at low temperature conditions, lithium crystals are easily precipitated on the negative electrode, resulting in internal short circuits and potential safety hazards, and the greater the charging current, the more serious such potential safety hazards

Lithium-ion battery at low temperature, the reaction of the cell electrode is very slow, the electrolyte will solidify, the battery performance is low, the charging time is shortened, the actual charging power is very small, and the actual performance of the battery is far lower than the battery calibration power when used, making Battery uptime dramatically reduced

In the existing technical solutions, the method of heating management is mainly used to solve the above hidden safety hazards, which is difficult to implement on electric vehicles running outdoors.

[0004] In addition, under high temperature conditions, the lithium-ion battery’s cell electrodes react very actively. If you continue to charge it with normal current or high current, the temperature inside the lithium-ion battery will be further increased, which will increase the risk of battery explosion.

Images