Lossless equalization controller and control method

Abstract

A lossless equalization controller and a control method belong to the technical field of battery equalization control. The controller comprises a battery pack formed by a plurality of cells, an equalization switch control module, an equalization power control module, an equalization power transformation module, an equalization charging control module, a system power supply module and a master control module, wherein the system power supply module supplies power to the equalization switch control module, the equalization charging control module and the master control module. The controller has the advantages of rapid equalization speed, safe and reliable equalization process, low cost and easy promotion and application. The control method includes detecting battery equalization degree, equalizing laggard cells in the battery pack when the battery equalization degree is equal to or greater than 0.3%, detecting system fault, clearing system fault and other detection steps. The equalization precision is high, and the equalization process is safe and reliable.

Description

technical field [0001] A lossless balance control device and a control method belong to the technical field of battery pack balance control. Background technique [0002] Micro electric vehicles are an important part of my country's new energy development strategy. Micro electric vehicles have gradually become an indispensable means of transportation for short- and medium-range consumers' daily travel. At present, the main bottleneck restricting the development of micro electric vehicles is power battery technology and battery management. technology. In recent years, the power battery technology applied to micro electric vehicles has made rapid progress, such as the electric drive assembly technology using high specific energy and relatively stable lithium iron phosphate battery and the capacitive lead-acid battery that significantly improves the life of lead-acid batteries. Electric drive assembly technology, etc., but the development of the supporting battery management te...

AI Technical Summary

Problems solved by technology

[0005] 1. Capacitors or inductors are used as the intermediate components of the energy transfer of each monomer in the battery pack, the equalization speed is slow, the long-term use of the equalization effect is poor, and the accuracy is low;

[0006] 2. The bidirectional DC conversion module is used as the intermediate module for the energy transfer of each monomer in the battery pack, which is costly and difficult to popularize and apply in micro electric vehicles

[0008] 1. Using inductance or capacitance as the energy transfer element, it needs to be connected in parallel with a capacitor or inductance through a switching device between every two adjacent single cells. By controlling the on and off of the switching device, the capacitor or inductance is used Realize the energy transfer one by one, because the energy is transferred step by step, so the equalization speed is slow; and because the battery pack is charged and discharged in multiple cycles for a long time, especially when it is charged and discharged in multiple deep cycles, the difference in capacitance performance between the cells will also be reduced. become larger, thereby accelerating the aging of capacitors or inductors, resulting in worsening equalization effects and accuracy, and resulting in greater differences in battery charge and discharge performance among the cells of the battery pack;

[0009] 2. The bidirectional DC conversion module is used as the intermediate module for the energy transfer of each monomer in the battery pack, that is, each battery cell is connected to a bidirectional DC / DC converter and then connected in series. Due to the relatively low voltage level of the battery cells, in general The battery cell is used as the low-voltage side, and constant voltage or constant current charge and discharge control can be carried out according to the needs of balance. This equalization method can charge and discharge all battery cells at the same time, and control the charging and discharging according to the capacity of different battery cells. Discharge current, but because each battery cell requires a bidirectional DC / DC converter, the cost is higher

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