Voltage balancing method and voltage balancing circuit of lithium-ion energy storage battery

Abstract

The invention discloses a voltage balancing method and a voltage balancing circuit of a lithium-ion energy storage battery. The voltage balancing circuit comprises a battery pack, a voltage sampling circuit, a DSP (digital signal processor) circuit and a two-way DC / DC (direct current / direct current) converter circuit, wherein the battery pack is provided with at least one first single battery and a second single battery, which are connected in series; the voltage sampling circuit is electrically connected with the single batteries; the DSP circuit is capable of controlling the voltage sampling circuit and receiving the feedback data of the voltage sampling circuit; the two-way DC / DC converter circuit is controlled by the DSP circuit; aiming at N sections of single batteries, the two-way DC / DC converter circuit comprises N-1 balance units; each balance unit comprises a first single battery, a second single battery, a first N-MOS field-effect tube, a second N-MOS field-effect tube, a first diode, a second diode, a first inductor, a second inductor and a capacitor. The circuit disclosed by the invention is simple in structure and easy to achieve; the converter circuit works at a relatively high frequency; the size of the inductor can be greatly reduced; the elements are all patch elements; the circuit is small in size, and easy to integrate in a PCB (printed circuit board) circuit; two-way energy flow control can be achieved; balance of the batteries can be rapidly achieved during charge or discharge of a lithium-ion battery pack.

Description

technical field [0001] The invention relates to the technical field of lithium-ion energy storage batteries, in particular to a voltage equalization method for lithium-ion energy storage batteries and a circuit thereof. Background technique [0002] The working voltage of lithium-ion cells is 3.7V or 3.2V, and the cell voltage is relatively low. In order to meet the voltage and capacity requirements of the energy storage system, battery cells are generally connected in series. However, due to individual differences in the internal resistance, self-discharge rate, state of charge, terminal voltage, etc. of lithium-ion monomers, long-term operation will cause differences in the capacity of the monomers, which will seriously affect the efficiency of the battery pack. The capacity balance of the body is the key technology to ensure the long-term efficient operation of the battery pack. [0003] In the prior art, lithium ion capacity equalization methods mainly include resistanc...

AI Technical Summary

Problems solved by technology

The specific implementation method is that in the switching cycle, when the switch is turned on, the battery 1 charges the inductor, and the inductor stores energy. When the switch is turned off, the energy of the inductor discharges to the battery 2 through the diode. This circuit only relies on the inductor for energy transfer, and only The current is output to the load when the switch is off, so the circuit efficiency is not high

Images