Charging management method and charger for lithium ion battery pack

Abstract

The invention discloses a charging management method and a charger for a lithium ion battery pack, relating to application of the lithium ion battery pack on power equipment. In order to solve the defects of the security, the cycle life and the low temperature charging capacity of the lithium ion battery pack in the prior art, the invention provides the charging management method for the lithium ion battery pack. In the method, the lithium ion battery pack is charged in the manner of periodicity, i.e. each period consists of a charging phase and a standing phase. For the noncontinuous charging method, the concentration polarization and the electrochemical polarization are great in charging, but the concentration polarization and the electrochemical polarization are balanced very quickly due to molecular motion when power is cut off, therefore, the polarization of the battery can be reduced or eliminated, the security of the battery pack is greatly improved, the cycle life is prolongedand the low temperature charging capacity is enhanced. The charging method can be applied to the lithium ion battery pack of electric equipment, such as an electric bicycle, an electric automobile, an electric ship, an electric plane, a submarine, a torpedo, and the like.

Description

technical field [0001] The invention relates to a charging management method of a lithium-ion battery pack applied to electric equipment such as electric bicycles, electric cars, electric boats, electric planes, submarines and torpedoes, and a used charger. Background technique [0002] In addition to simple handheld devices such as mobile phones, MP3, and MP4, lithium-ion batteries are also applied to many electric devices. Because its rated voltage is far from the rated voltage of these electric equipment, and the capacity is not necessarily appropriate, it must be connected in series and parallel to form a battery pack to work. Under the condition of series-parallel operation of the battery pack, the consistency difference of the internal resistance, capacity, voltage, temperature, self-discharge and other parameters of the single battery greatly affects the working efficiency of the battery pack, especially in extreme conditions (such as high current discharge, Low temp...

AI Technical Summary

Problems solved by technology

However, in winter in the north, due to the low temperature, the use of lithium-ion batteries that need to be charged outdoors is greatly limited.

[0005] All of the above problems stem from the polarization of the battery and the poor consistency of the individual cells within the battery pack

[0006] Since the battery pack works under the management of the power management system (BMS), and the worst battery is used as the standard when the battery pack is working, when the battery pack is charging, when the worst battery is full but the other batteries are not yet full, the management system defaults The battery pack is fully charged; similarly, when the battery pack is discharged, when the worst battery is discharged but the other batteries are not fully discharged, the management system defaults that the battery pack has been discharged, so the consistency of the battery is poor, which will lead to a short cycle life of the battery

When the battery pack is charged, due to the management system accuracy and other reasons, the worst battery is very likely to be overcharged; similarly, when the battery pack is discharged, the worst battery is very likely to be over-discharged, and overcharge and over-discharge will cause the battery to overcharge. The safety problem of the battery, so the poor consistency of the battery will reduce the safety of the battery

In addition, due to the reduction of molecular motion due to low temperature, batteries with poor consistency will have poorer chargeability due to greater polarization differences

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