Security Protection Circuit Research On Smart Lithium-ion Battery System

Now the new energy still do not have the ability to solve the immediate energyproblems, the research and application of energy storage system are particularlyimportant. Lithium ion battery is one of the most widely used energy storage system atpresent, it has many good qualities, such as high working voltage, low self-discharge,long cycle life, that let it under the spotlight. However, according to the work principleof lithium ion battery, it is known that it work in a state which has very strictrequirement of the voltage and current. In fact, when the lithium ion battery has higherlotus electricity state, the positive oxidizing and negative oxidizing reducing is stronger,its reaction activity with electrolyte is stronger, performance for a serious flatulence ofthe battery. Thus, the lithium battery protection circuit design and use is very important.The lithium ion battery demand in domestic increase, and thus many domesticcompany rolled out their respective power protection IC. And then use extensivelybattery protection IC’s function is relatively single, scalability and portability is poorer,can’t meet the demand for the development of intelligent equipment. This paper basedon this issues, proposed a protection circuit design based on microprocessor STM32andlithium ion battery protection chip X3100. The main features of Lithium ion batteryprotection circuit include: detection of battery charging, discharge, over current andtemperature protection, etc.The work principle of the circuit, the selection principle of other components in thecircuit, and the realization of the function of circuit protection is introduced in this paper.One of the most important protection circuit is control circuit of lithium ion battery’scharging and discharging, two control FETs respectively control the battery chargingand discharge circuit, when the batteries in any abnormal situation, disconnect thecorresponding control FET (sometimes must disconnect two of all) to achieve thepurpose of protecting the battery. Protect chip and micro controller communicate by SPIcommunication, micro controller chip send instructions to protect chip, and protect chiptransfer data to microprocessor chip. On this basis, loadμ C/OS-II real-time operatingsystem to the microprocessor, making the system operation intelligent, strengtheningconnectivity with PC and user.Through the combination of RealViewMDK and Proteus simulation, circuit canfinished protection of the lithium ion battery pack, which consist of4single lithium ionbattery, over voltage protection, owe voltage protection, over current protection, voltageequilibrium and temperature protection etc.