Lithium battery protection circuit and protection method thereof

Abstract

The invention discloses a lithium battery protection circuit and a protection method thereof. The protection circuit is arranged in the lithium battery pack and is connected with the two poles of the cell of each battery forming the lithium battery pack, and comprises a front end acquire unit, an MCU master unit and a charging and control unit. The protection method comprises that the front end acquiring unit acquires parameters of the voltage of the cells of the batteries in real time and transmits the parameters to the MCU; according to the given charging current and the read data, the MCU calculates and outputs a control signal of PWM to control a charger for charging; the MCU reduces the charging current for charging or stops the charge in due time so as to necessarily protect the batteries. The protection circuit and the protection method adopt a feedback mode of simple link cell voltage, thereby effectively avoiding the defects of charging management when only the voltage of two poles Pack+ and Pack- of the lithium battery is taken as the reference; and when the voltage of the cell of a certain link reaches the amplitude limiting value, the MCN regulates the command to reduce the charging current and prevents the voltage of the battery from overrunning, thereby ensuring the safety of the lithium battery and improving the charging efficiency at the same time.

Description

technical field [0001] The invention relates to the technical field of lithium battery protection, in particular to a protection circuit and a protection method for a lithium battery applied to an electric bicycle. Background technique [0002] At present, conventional lithium battery packs for electric bicycles only have lithium battery protection functions, and a few lithium battery packs support simple equalization functions. Usually, such protection systems are called lithium battery protection boards, and the charging management of the batteries is completed by an external charger. , The connection between the charger and the battery pack is relatively simple, that is, through the Pack+ and Pack- terminals. The charging process is generally constant current first and then constant voltage. When the current during the constant voltage process drops to about 0.01C, the charging is considered complete. For battery packs with too low voltage, trickle pre-charging is genera...

AI Technical Summary

Problems solved by technology

The disadvantage of this charging management is that it only feeds back the port voltage of the battery pack. When the consistency of the cells in the battery pack is good, this charging method can achieve the expected effect; , the voltage of a battery cell reaches the limit voltage in advance during the charging process. In order to avoid overcharging and damage to the lithium battery, the protection board will cut off the charging circuit. to charger setpoint

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