Optimal charging method for lithium-ion power battery

Abstract

The invention discloses an optimized charging method of a lithium-ion power battery. The optimized charging method comprises the following steps: firstly, using various currents to perform constant-current charging experiments on a lithium-ion battery, stopping charging when the terminal voltage reaches the maximal voltage of a single battery, recording the electrical quantity charged in the lithium-ion battery at the moment, selecting the charging current of which the charged electrical quantity is maximum as a charging current value in the first charging stage; secondly, performing constant-current charging on the battery according to the charging current value in the first charging stage; thirdly, continually performing second-charging-stage charging on the lithium-ion battery by the positive and negative pulse combined manner, dividing the second charging stage into two charging sub-stages, charging the lithium-ion battery with positive pulses of which the amplitudes decrease step by step in the two charging sub-stages, and adding a negative pulse between every two adjacent positive pulses. The optimized charging method cannot damage the power battery or influence the service life of the battery while quickly and efficiently charging the power battery.

Description

technical field [0001] The invention relates to the technical field of charging lithium-ion power batteries, in particular to an optimized charging method for lithium-ion power batteries. Background technique [0002] At present, there are mainly four charging methods for power battery chargers for electric vehicles, namely constant current charging, constant voltage charging, two-stage or three-stage charging and pulse charging. According to the best charging curve of the battery, it can be seen that as the charging process progresses, the ideal charging current acceptable to the battery should gradually decrease, so if a constant current is used for charging, the charging current will decrease for the battery in the later stage of charging. If it is too large, the battery will be overcharged. Constant voltage charging method The current is too large at the beginning of charging. Excessive charging current will make the battery prone to polarization reaction in the initial...

AI Technical Summary

Problems solved by technology

According to the best charging curve of the battery, it can be seen that as the charging process progresses, the ideal charging current acceptable to the battery should gradually decrease, so if a constant current is used for charging, the charging current will decrease for the battery in the later stage of charging. Too large, causing the battery to overcharge

Constant voltage charging method The current is too large at the beginning of charging. Excessive charging current will make the battery prone to polarization reaction in the initial stage of charging. In the later stage of charging, the charging current is too small for the battery. Too small charging current It is easy to cause the battery to be insufficiently charged in the later stage of charging.

The two-stage or three-stage charging method combines constant current charging and constant voltage charging. During the charging process, the gassing reaction of the battery can be effectively controlled and the energy loss can be reduced. However, during the charging process, mode switching is required. , so the control system is relatively complex, and there are also disadvantages contained in the constant current and constant voltage charging method

The pulse charging method is more effective in eliminating or reducing polarization, but its energy conversion efficiency is relatively low

In short, when the above charging method is used for charging, the battery will be polarized during the charging process, resulting in long charging time and low charging efficiency.

In order to achieve the purpose of fast charging, the measure of increasing the charging current is generally adopted, which will lead to the problem that the internal resistance of the battery increases and the temperature of the battery rises too fast during the charging process, which may easily lead to permanent damage to the battery.

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