Parallel charging and discharging control method and system for battery pack

Abstract

The invention discloses a parallel charging and discharging control method for a battery pack. The method comprises the following steps: detecting an actual current value of each of battery branches connected in parallel in real time; comparing the actual current values of all the battery branches to obtain a maximum actual current value; determining a safety current value of the battery system; comparing the maximum actual current value with the safety current value; and adjusting the battery system based on the comparison result of the maximum actual current value and the safety current value. According to the method, charging and discharging control on the battery system is realized by monitoring the current changes of different parallel branch batteries in real time and dynamically adjusting the load or the charging voltage of the battery system according to the upper limit threshold value of the current-withstanding characteristic of the batteries, and the excessive influence of circulating current caused by inconsistency of capacity, open-circuit voltage, state of charge, internal resistance and the like in the battery system is eliminated in the whole using process. Moreover, the control mode can meet the starting power requirement of a locomotive and give play to the characteristics of the power battery system to the maximum.

Description

technical field [0001] The invention relates to the field of charge and discharge control of locomotive power batteries, and more particularly relates to a method and system for controlling charge and discharge of battery packs connected in parallel. Background technique [0002] As the country advocates green energy, the rolling stock industry (such as high-speed rail, bullet train, urban rail, subway and railway locomotive) has gradually increased the number of projects using power batteries. [0003] Traction batteries for rolling stock have the characteristics of large capacity and large power. Especially from the perspective of locomotive redundancy, most of them adopt multi-branch parallel circuit topology. However, during the long-term cycle use of the power battery, due to the influence of self-discharge and temperature difference, there will be inconsistencies in the state of charge, capacity and internal resistance. In the parallel circuit topology, the voltage be...

AI Technical Summary

Problems solved by technology

The circulating current phenomenon will cause the current of some batteries to be very small, while the current of the other part of the battery is too large, which may exceed the current range that the battery can withstand, resulting in accelerated aging of the battery pack, which greatly affects the life of the battery and the performance of power and energy characteristics.

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