Charging and discharging protector for multi-cell lithium ion battery

Abstract

The invention designs a charging and discharging protector for a multi-cell lithium ion battery. The device comprises a battery pack, an equalization module, a discharging detection module, a charging control module, a discharging control module, a charging detection unit and a discharging driving resistor; the battery pack is formed by connecting n battery cells in series, n is greater than or equal to 2, and each battery cell is respectively connected with n equalization units in the equalization module and n discharge detection units in the discharge detection module in parallel. Compared with the prior art, each single lithium ion battery cell is provided with the independent charging and discharging detection unit and the balancing unit, the structure is very simple, the price is very low, and the multi-cell lithium ion battery protection control circuit is suitable for protection control of a multi-cell lithium ion battery; voltage detection and protection control of the lithium ion battery are integrated; charging protection, discharging protection and battery cell balancing are independently carried out, so that the reliability is improved; the charging cut-off voltage, the discharging cut-off voltage and the equalization voltage can be adjusted through resistance values.

Description

technical field [0001] The invention relates to a battery management system of a lithium ion battery, in particular to a charging and discharging protection device for a lithium ion battery with multiple batteries. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, good safety performance, and long cycle life, and are widely used in the new energy automobile industry, starting power supply, energy storage market, and military fields. However, if the lithium-ion battery is overcharged, the electrolyte and other materials will decompose and produce gas, which will cause the battery shell or pressure valve to bulge and rupture, and then explode; if the battery voltage is too low, some materials inside the battery will begin to be destroyed, and Because the battery will self-discharge, the longer it is placed, the lower the voltage will be; in addition, when the charging current is too high, lithium ions will not have time to enter th...

AI Technical Summary

Problems solved by technology

[0003] Chinese patent CN112234689B discloses a charge-discharge protection circuit and a lithium-ion battery protection system. Two comparators are used to collect the lithium-ion battery voltage, and a charge-discharge control circuit is formed by a plurality of digital integrated circuits. The structure is relatively complicated. Since only one The MOSFET is used as a power switch, which can only control the charging. If the discharge is to be controlled, the invention also needs to design a MOSFET as a discharge power switch.

[0004] Patent No. CN104682355B discloses a lithium-ion battery protection circuit, which requires a special multi-way switch and a voltage comparison circuit, and also requires a plurality of digital integrated chips to form a logic circuit. In order to realize charge and discharge control, four field effect transistors are used, and the control logic very complicated

[0005] In addition, the current charge and discharge protection of lithium-ion batteries mostly uses integrated voltage acquisition and control circuits, which are costly and need to configure control parameters through the host computer. The use process is relatively complicated, which is not conducive to multi-cell lithium-ion batteries, or different Types of Li-ion Batteries for Applications

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