Flyback circuit-based battery pack lossless balance circuit

Abstract

The invention discloses a flyback circuit-based battery pack lossless balance circuit. The battery pack lossless balance circuit comprises a battery pack which consists of n batteries connected in series and a balance module connected with the battery pack; the balance module comprises a control module, and a first balance unit, a flyback circuit and a second balance unit which are electrically connected in sequence; the first balance unit and the second balance unit are connected with the battery pack separately; the flyback circuit comprises a flyback transformer; the first balance unit is electrically connected to a primary coil of the flyback transformer; the second balance unit is electrically connected to a secondary coil of the flyback transformer; each of the first balance unit and the second balance unit consists of n switch assemblies connected in parallel; and each switch assembly consists of two MOSFET switches connected in an anti-parallel manner. By only adopting one flyback circuit for energy transferring, energy exchange between any two batteries in the whole battery pack can be realized; and meanwhile, by controlling the on-off of the MOSFET switches connected in an anti-parallel manner and the effect of the flyback transformer, the electric quantity balance of the battery pack is realized, maintenance of the batteries is reduced, and the service life of the battery pack is prolonged.

Description

technical field [0001] The invention relates to the battery field, in particular to a non-destructive equalization circuit for a battery pack based on a flyback circuit. Background technique [0002] After the battery pack has gone through multiple charge and discharge cycles, there are roughly three situations in the distribution of the remaining capacity of each battery cell: the remaining capacity of some battery cells is high; the remaining capacity of some battery cells is low; The remaining capacity of some battery cells is high and the remaining capacity of some battery cells is low. In view of the above three situations, scholars at home and abroad have proposed different solutions for the balance control of lithium-ion battery packs. According to the energy consumption of the circuit during the balance process, they can be divided into two types: energy dissipation type and energy non-dissipation type. kind. [0003] In view of the high remaining capacity of indiv...

AI Technical Summary

Problems solved by technology

[0003] In view of the high remaining capacity of individual battery cells, some researchers have proposed energy dissipation solutions such as parallel resistor shunt method, which consumes the energy of battery modules with high remaining capacity through resistance by controlling the corresponding switching devices. This method wastes energy in vain, and generates a lot of heat during the equalization process, which increases the load of battery thermal management.

Some researchers have also proposed equalization circuits such as bidirectional DC-DC equalization method and coaxial transformer equalization method. These circuits all use transformers, which increase the cost of equalization circuits.

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