A battery pack equalization circuit and its equalization method

Abstract

The invention discloses a battery pack equalizing circuit and method. The circuit comprises a battery pack, a voltage collecting module used for collecting the voltage of single batteries in the battery pack, a switch switching module, a control module and at least one bidirectional DC-DC module, and the bidirectional DC-DC module is connected with the battery pack. The control module is used for judging whether the single batteries need to be equalized or not according to the collected voltage of the single batteries; when the judgment result is that the single batteries need to be equalized, the switch switching module is controlled to enable the single batteries needing to be equalized to be connected with the bidirectional DC-DC module, and then the bidirectional DC-DC module is controlled to enable energy to flow among the battery pack and the single batteries needing to be equalized. The battery pack equalizing circuit and method have the advantages that the radiating aim is achieved, the equalizing current is large, the equalizing speed is high, and the energy utilization rate is high. The battery pack equalizing circuit and method can be widely applied to the field of battery management.

Description

technical field [0001] The present invention relates to a battery management system, in particular to an equalization circuit and an equalization method for controlling the battery cells used in series during the charging and discharging process of the battery pack so as to balance the power of all the battery cells. Background technique [0002] In the actual use of the battery, the voltage and capacity of the single battery often cannot meet the needs of the load, so it is often necessary to connect multiple single batteries in series or parallel to form a group 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 ...

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

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; Transmission, so the energy loss is large, and the energy utilization rate is still relatively low

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