Lithium ion battery charge and discharge protective circuit and lithium ion battery system

Abstract

The invention discloses a lithium ion battery charge and discharge protective circuit. The lithium ion battery charge and discharge protective circuit comprises an MOS (Metal Oxide Semiconductor) switch unit, a charge and discharge protective unit and a direct current contactor unit, wherein the charge and discharge protective unit and the direct current contactor unit are connected with the MOS switch unit; the charge and discharge protective unit carries out data real-time acquisition and data judgment and comparison on a lithium ion battery pack and outputs a control signal; when an abnormal situation such as over-charge or over-discharge and the like occurs in the lithium ion battery pack, the charge and discharge protective unit outputs the control signal of a charge abnormity or a discharge abnormity; the MOS switch unit controls the direct current contactor unit to switch off or switch on a charge and discharge circuit according to the control signal so as to achieve the effect of protecting the lithium ion battery pack. Meanwhile as a direct current contactor can enable high working currents to pass, the circuit is suitable for a lithium ion battery system for charge and discharge of high current more than hectoampere.

Description

technical field [0001] The invention relates to the technical field of battery charge and discharge protection, in particular to a lithium ion battery charge and discharge protection circuit and a lithium ion battery system. Background technique [0002] Lithium-ion battery is a secondary battery (rechargeable battery) that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During charging and discharging, Li+ intercalates and deintercalates back and forth between the two polar terminals. During charging, Li+ deintercalates from the positive electrode, intercalates into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge. Lithium-ion battery is an electric energy storage device widely used in the field of consumer electronics and power storage. There are protection circuits in actual use, and the protection circuits usually have functions...

AI Technical Summary

Problems solved by technology

[0004] In recent years, lithium-ion batteries have been widely used in the fields of automobile starting batteries, electric vehicles and energy storage. Unlike the consumer field, the current of lithium-ion batteries in these application fields may be as high as 100 amperes or higher. At this time A single MOS tube cannot meet the requirements for passing large currents

like figure 1 As shown, for lithium-ion batteries with low current (such as tens of amperes of electric bicycles), it is usually solved by connecting multiple MOS tubes in parallel, but for protection circuits with hundreds of amperes or larger currents, multiple MOS tubes are usually used to solve the problem. The tubes M1~Mn are connected in parallel, which is not only bulky and expensive, but also easily burns out some MOS tubes due to unbalanced current distribution when there is a short circuit or a large current flows.

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