Autonomous equalization circuit of battery pack

Abstract

The invention relates to an autonomous equalization circuit of a battery pack. The autonomous equalization circuit comprises a battery voltage detection circuit, a bidirectional energy storage charging circuit and a controller, wherein the battery voltage detection circuit comprises n voltage detection units which are connected with the single batteries in a one-to-one correspondence manner; the voltage detection unit comprises a voltage detection NMOS transistor; the bidirectional energy storage charging circuit comprises an energy storage transformer, an energy transfer NMOS transistor and ncharging and discharging units connected with the single batteries in a one-to-one correspondence manner; the energy storage transformer comprises a primary coil and n secondary coils in one-to-one correspondence with the single batteries; the charging and discharging unit comprises a charging and discharging PMOS transistor; and the controller is connected with each voltage detection NMOS transistor, each energy transfer NMOS transistor and each charging and discharging PMOS transistor. According to the invention, energy lossless transfer can be realized, so that the purpose of battery equalization is achieved, the structure is simple, and the efficiency is high.

Description

technical field [0001] The invention belongs to the field of battery management (BMS), and in particular relates to an autonomous equalization circuit of a battery pack. Background technique [0002] Lithium battery (battery pack) is an important part of lithium battery products such as electric vehicles, electric tools, and rechargeable vacuum cleaners. How to prolong its service life has been a problem that has plagued developers of lithium battery products. The root cause of this problem is multiple series connections. Under the battery is not balanced. Aiming at the problem of unbalanced batteries, a corresponding solution is needed. [0003] In the current battery pack lithium battery equalization design, most of them adopt passive equalization management method. Generally, the battery with higher voltage is discharged through resistance discharge, and the power is released in the form of heat. In this way, the power of the whole system is limited by the battery with t...

AI Technical Summary

Problems solved by technology

When a certain battery is too high, first connect the capacitor to the battery with high voltage in parallel, and then switch the capacitor to the adjacent battery after the capacitor voltage is consistent with the battery voltage, and the capacitor charges the battery to realize capacity transfer, while Capacitors do not consume energy and can achieve energy-free transfer. However, this method is more complicated to control and requires a huge switch array. It is difficult to develop, the efficiency is relatively low, and the cost of supercapacitors is relatively high.

[0004] It can be seen that the problems of the existing battery pack equalization scheme are: 1. Energy waste; 2. Complex structure; 3. Low efficiency

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