Battery set equalization circuit based on soft-switch full bridge circuit and method

Abstract

The invention discloses a battery set equalization circuit based on a soft-switch full bridge circuit and a method. The battery set equalization circuit comprises a battery set equipped with multiple battery monomers, a voltage collection circuit, a switching circuit, a controller and at least one soft-switch full bridge bi-directional DC-DC circuit. The method comprises the steps that the voltage collection circuit collects voltages of each battery monomer in the battery set; according to the collected voltages of each battery monomer, whether equalization shall be implemented to the battery monomer is judged; if the judgment result indicates that the battery monomer requires the equalization, the controller can control the switching circuit, so that the battery monomer in need of the equalization can be connected to the soft-switch full bridge bi-directional DC-DC circuit; and the soft-switch full bridge bi-directional DC-DC circuit is controlled, so that energy can flow between the battery set and the battery monomer in need of the equalization. The equalization circuit disclosed by the invention can provide an equalizing current of 10A or more than 10A, and can satisfy the demand of large-power equipment for the equalizing current of 10A or even more than 10A. The circuit and the method disclosed by the invention can be widely applied in the field of battery equalization.

Description

[0001] technical field [0002] The invention relates to battery group equalization technology, in particular to a battery group equalization circuit and method based on a soft-switching full-bridge bidirectional DC-DC circuit. Background technique [0003] In the actual use of the battery, the voltage and capacity of the single battery often cannot meet the demand of the load, so it is often necessary to connect multiple single batteries in series and parallel to form a battery pack before use. However, due to the limitations of the production process in the production process of different single batteries, there are often differences in the initial conditions of use (small differences in capacity), and in the process of use, different working conditions (such as differences in temperature and aging) also There will be differences in performance between battery cells. After repeated charging and discharging, if these differences are not controlled, they will gradually expa...

AI Technical Summary

Problems solved by technology

However, the passive equalization method has the following four obvious defects: 1. Since the excess energy is dissipated in the form of heat through the load, the resulting heat will cause great problems for heat dissipation, and at the same time, battery overheating will also increase battery life. 2. The equalization current of passive equalization is small, so the equalization time is longer, and it can only be applied to small-capacity batteries; 3. The working principle of passive equalization is that when the power of a certain battery is higher than After the preset value, the equalization is turned on, otherwise the equalization is turned off, so the equalization function can only be turned on at the end of charging, and the equalization cannot be performed at the front end of charging and during the discharge process; 4. Because the consumed energy cannot be used by the system, resulting in Energy waste, resulting in low energy utilization of the entire system

However, the distributed active equalization circuit has the following two defects: 1. Because the equalization needs to be performed on all adjacent battery cells, the equalization current is small and the equalization speed is slow; 2. Since the energy is transferred between different battery cells Multiple transfers, so the energy loss is large, and the energy utilization rate is still relatively low

However, the core component of the centralized active equalization circuit is usually a DC-DC circuit, and whether it is a flyback DC-DC circuit or a forward DC-DC circuit, the equalization current they can provide does not exceed 5A, so , for high-power equipment, when a balance current of 10A or even higher is required, the current centralized active balance circuit based on a flyback DC-DC circuit or a forward DC-DC circuit cannot meet this requirement

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