The Design Of Li~+ion-Battery Protection Circuit System

With the gradual application of lithium ion batteries in different fields,in order to correctly analyze the faults occurred in the practical use of multi-series large capacity lithium ion batteries and continuously improve product function and quality,so need to track the status parameters of the battery pack actually used,these state parameters are read through dedicated user software to provide raw data support for failure analysis.However,the protection circuit which is widely used in battery packs is a hardware protection circuit with only basic protection function,unable to record battery status parameters.Therefore,the protection circuit should be designed as a combination of hardware and software to protect the circuit system.The system not only implements overvoltage,undervoltage,overcurrent and other basic protection functions,and also estimate the remaining capacity of the battery,to achieve data,voltage,current,temperature and remaining capacity data recording,communication and display functions.In order to save the battery power,in addition to requiring protection circuitry,the system can reliably implement the various functions described above,the power consumption of the system must be small enough.On such a premise,this topic develops a more practical protection circuit system according to the actual requirements of the project.This paper introduces the design of hardware and software of the protection circuit system.it mainly includes the whole scheme of the circuit system,the protection module circuit,the capacity estimation module circuit,the MCU module circuit and the power supply module design and test.The whole design of the circuit system includes the constitution of the protective circuit,the function and the selection of the key devices;the protection module circuit design includes hardware circuit design,can protection,communication,sleep and wake-up mechanism;capacity estimation module circuit design,including hardware circuit design,can realize remaining capacity estimation and onlin display,communication,sleep and wake mechanism;MCU module circuit design,including hardware and software design,can achieve data recording,communication between upper and lower computer,sleep and wake up function;the design of power supply module includes hardware circuit design,DC power supply,sleep and wake-up function.This paper mainly uses the Altium Designer 6 electronic design tool to design the circuit schematic diagram and the printed circuit board,using Keil software compiler tools to write code,the lithium ion battery,protective circuit,integrated test equipment,programmable power supply,electronic load and oscilloscope are used to test the function and performance,the test results meet the design requirements.