Research And Design Of High-accuracy Strategy Of Li-ion Battery Fuel Guage And Data Acquisition Circuit

Li-ion battery is widely used in notebook computers and a variety of handheld devices due to its high energy-to-weight ratio and non-polluting. With the improvement of people’s environment protection consciousness and deepening of the energy crisis, Li-ion battery has spread into other fields such as electric vehicle and space aircraft. The development of Li-ion battery also propose harsher technological standard of battery fuel gauge. People hope to portable devices like notebook computer can display the remaining run-time.So high-accuracy strategy of Li-ion battery fuel gauge and hardware circuit have great application value.This thesis firstly introduces the research status and gives the advantages and disadvanges of different strategy of Li-ion battery fuel gauge.Then it describes Li-ion battery working principle and influence factors of the internal impedance.Based on the traditional strategy of battery fuel gauge,the high-accuracy method can accurately determine the remaining run-time of a device powered by the battery through organically combining with open circuit voltage method and coulomb counter method.Meanwhile,the proposed strategy can update the database of the internal impedance and initial capacity and the discharge curve in real time.In order to improve the accuracy in determining the remaining run-time,the adaptive algorithm effectively compensates the influence of the self-discharge rate, temperature and the battery age by dynamic model-building approach.The paper mainly analyses the high-performance data acquisition circuit of the temperature and voltage of Li-ion battery. It mainly includes the following sub-modules in this circuit: chopper amplifier, switched capacitor bandgap reference, auxiliary circuit. After the analysis, the sub-modules and the overall circuit are simulated by SMIC 0.13 um technology library and HSPICE. The simulation results reach expected purpose.Comparing with other method of Li-ion battery fuel gauge, the proposed high-accuracy strategy of Li-ion battery fuel gauge can monitor the self-discharge, temperature and the battery age of Li-ion battery.So the proposed strategy can prolong the remaining run-time of PDA, electric tools and healthcare facilities etc. Moreover, the proposed high-performance data acquisition circuit of the temperature and voltage of Li-ion battery have the advantages of high veracity and high sensitivity, so it can be applied to battery management system.