An automatic equalization control method without battery cell voltage sensor

Abstract

The invention discloses an automatic equalization control method without a battery monomer voltage sensor. According to the method, the voltage of battery monomers is compared with the average voltage of a battery pack, so that the energy flow direction is determined, a current monomer qualified flag bit is reset, and according to the magnitude of the voltage of the monomers and the average monomer voltage of the battery pack, the output voltage and the working mode of a Buck-Boost conversion module are determined; comparison is achieved through a voltage comparator each time, the battery monomer voltage sensor is not needed, and system erection cost is saved; the allowable voltage difference range between the monomer voltage and the average voltage is set, when the monomer voltage is within the range, the battery monomers are not equalized, a next battery monomer is directly jumped to, system control time and equalization time are greatly shortened, the equalization frequency is reduced, the equalization efficiency is effectively improved, and excessive equalization is avoided.

Description

technical field [0001] The invention relates to an automatic equalization control method for a battery-free single voltage sensor. Background technique [0002] The world is facing an unprecedented energy and environmental crisis, and the worldwide energy shortage and environmental deterioration have attracted the attention of all countries. Electric vehicles have the characteristics of energy saving and environmental protection, which is the key way to solve this major crisis, and has become an inevitable trend in the future development of the automobile industry. As an important part of the world's energy technology revolution and the national new energy strategy, electric vehicles are one of the country's seven strategic emerging industries. Lithium-ion batteries have the advantages of small size, light weight, fast charging speed, and good anti-memory effect compared with nickel-hydrogen and lead-acid batteries. They are widely used as power sources in electric vehicles...

AI Technical Summary

Problems solved by technology

However, in this equalization circuit, when the voltage of a certain battery cell is low, while the voltage of other battery cells is in a balanced state, one switch is required to complete the equalization; High, and when the voltage of other cells is in balance, n-1 switching cycles are required to complete the balance

Therefore, the Pack to Cell equalization circuit needs n / 2 switching cycles on average, the equalization speed is slow, and the efficiency is low. It is only suitable for one or several cells in the battery pack with low voltage and other cells In the case of a balanced state, it is not suitable for the case where one or several battery cell voltages are relatively high while other battery cell voltages are in a balanced state

[0008] For the Cell to Pack type equalization circuit, when the voltage of a certain battery cell is high, while the voltage of other battery cells is in balance, it needs to be switched once to complete the balance; when the voltage of a certain battery cell is low , and when the voltage of other cells is in balance, n-1 switching cycles are required to complete the balance. Therefore, the Cell to Pack type equalization circuit needs n / 2 switching cycles on average, and the equalization speed is slow and the efficiency is low. , it is only suitable for the situation that one or several battery cells of the battery pack have a higher voltage and the other battery cells are in a balanced state, and it is not suitable for one or several battery cells with a lower voltage and other battery cells When the voltage is in balance

[0009] In the traditional equalization circuit, the voltage sensor is required to collect the voltage of the single battery to the microcontroller, and then the microcontroller compares the voltage signal and outputs the control signal. This process takes a long time and many resources, making The control cycle is long, the efficiency is low, and the automatic balance between the monomer and the battery pack cannot be realized

When balancing each cell, regardless of whether the voltage of the cell is within the specified range, the cell will be balanced for a specified time, which will cause unnecessary waste of time and energy when the current cell itself has been balanced. Waste, which greatly reduces the equalization efficiency and prolongs the total equalization time

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