Multi-cell serially-connected lithium battery pack equalization and protection system

Abstract

The invention discloses a multi-cell serially-connected lithium battery pack equalization and protection system. The system comprises a lithium battery charge and discharge component, a control module, a charge and discharge switching device, a discharge end abnormality protection circuit and a system abnormality protection circuit, wherein the lithium battery charge and discharge component is used for connecting an external charging power supply into a lithium battery pack for charging and supplying power to a load, the control module is used for IIC (inter-integrated circuit) communication with the lithium battery charge and discharge component so as to control the same to be fully charged, the charge and discharge switching device is used for closing or opening a charge hoop or a power supply loop of the lithium battery charge and discharge component, the discharge end abnormality protection circuit is used for detecting discharge overcurrent of a discharge end and sending an overcurrent protection signal when detecting the discharge overcurrent of the discharge end, and the system abnormality protection circuit is used for detecting IIC communication states and discharge end discharge states and sending a system abnormality protection signal when detecting IIC communication abnormalities and / or discharge overcurrent of the discharge end. Besides, the charge and discharge switching device opens the discharge loop or the power supply loop according to the system abnormality protection signal.

Description

technical field [0001] The invention relates to the field of power supplies, in particular to a balance and protection system for a multi-series lithium battery pack. Background technique [0002] In recent years, because lithium batteries have many advantages such as stable discharge voltage, low self-discharge rate, long life, no memory effect, small size, and no pollution, they are widely used in testing instruments, digital products, power tools, etc. figure 1 It shows a structural block diagram of a multi-series lithium battery pack system provided by the prior art, including lithium battery charging and discharging components, a control module and a charging and discharging switch device. The control module controls the charging and discharging switch device to connect or disconnect the charging loop or the power supply loop according to the charging or discharging status of the multi-series lithium battery pack system. At present, the following problems still exist i...

AI Technical Summary

Problems solved by technology

[0003] 1. When the IIC communication between the lithium battery charging and discharging components and the control module is abnormal, it may lead to abnormal or invalid charging and discharging protection, which will make the use of lithium battery packs out of control and even cause accidents;

[0004] 2. The output capacity of the lithium battery pack is too low. When an overcurrent or even a short circuit occurs at the discharge end, it is not enough to provide a large enough current to trigger the discharge overcurrent and short circuit protection, resulting in safety out of control;

[0005] 3. When an overcurrent or even a short circuit occurs at the discharge end of the multi-series lithium battery pack system, it may cause safety issues in the charging and discharging of the lithium battery pack;

[0006] 4. Due to the voltage, internal resistance, and capacity differences between the individual lithium batteries of the lithium battery pack, the consistency error of the full charge voltage is caused. For the same load, the greater the voltage difference of the lithium battery, the shorter the charging and discharging time of the lithium battery pack. The lower the continuous discharge capacity of the battery pack

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