Battery pack equalization module, system and control method based on bidirectional flyback converter

Abstract

The disclosure provides a battery pack balancing module, system and control method based on a bidirectional flyback converter. Wherein, the battery equalization module includes a bidirectional flyback converter, the primary side of which is connected in series with the first battery module through the first switch tube, and the secondary side is connected in series with the second battery module through the second switch tube; the first battery module includes A number of battery cells connected in series; both ends of each battery cell are connected to the two ends of the primary side of the bidirectional flyback converter through the reverse series connection of the third switch tube and the fourth switch tube; the first switch tube, the second switch tube The switch tube, the third switch and the fourth switch tube are all connected to the microcontroller, and the microcontroller is used to compare the voltage of each battery cell with the average voltage of all battery cells to select the optimal discharge battery combination and rechargeable battery combination, and then The switching tubes on the corresponding side of the bidirectional flyback converter corresponding to the battery module to which the battery pack belongs are controlled to be turned on or off by the PWM control signal, so as to realize battery pack balancing.

Description

technical field [0001] The disclosure belongs to the field of power electronic control, and in particular relates to a battery pack equalization module, system and control method based on a bidirectional flyback converter. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] As the heart of electric vehicles, the power battery pack is often composed of hundreds or thousands of lithium-ion battery cells connected in series or in parallel to meet the voltage and power levels of electric vehicles. However, due to differences in the manufacturing process and working environment of lithium-ion batteries, there are slight differences in the internal resistance and capacity of each battery cell. Especially after multiple charging and discharging cycles in groups, these small differences will gradually accumulate, resulting in increased inconsistency...

AI Technical Summary

Problems solved by technology

However, the inventors have found that each battery cell in this balancing circuit needs to use four switching devices, which is large in size and high in cost; secondly, when the number of discharged batteries is small and the number of rechargeable batteries is large, the balance current will become smaller, reducing the Equalization speed; finally, when multiple batteries are equalized to a single battery, due to the characteristics of LC resonance transformation, the overall equalization efficiency becomes lower

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