Application Of AH Computation On SOC Evaluation Of The Lithium-ion Battery In The Environment Of MATLAB

The flourishing development of the car industry accelerates the rapid development of the world economy, which bring the convenience together with the energy sources and environment problems to us. At present, the dynamical batteries used to electrical cars have been developed, such as lead-acid battery, nickel-cadmium battery, nickel-hydrogen battery and lithium-ion battery, which can release or solve the energy sources and environment problems. In order to optimize the using status of the battery and prolong the life of the battery, a kind of equipment is cried for, which can real timely reflect the remaining quantity of electricity, quickly find out the error of the battery and improve the life of the whole battery, namely the battery-manage system.Nowadays, the battery-manage system is especially important to the evaluation of the remaining quantity of electricity. At present, the methods of the evaluation of the remaining quantity of electricity includes discharge-experiments method, Ah computation method, open potential methods (which are often used before), Nerve network method, linear-blurred arithmetic and kalman method (which are used often nowadays). Compared to the foregoing methods, the later three methods have a lot of improvement in definition. But many problems are come down to. Except for high cost, more parameters together with more influence factors make the estimation methods more and more complicated. Moreover, the different parameters are adopted to conduct soc estimation due to the different reaction mechanism and character of different batteries. In this paper, the A-H measurement method is adopted to estimate the soc of the lithium-ion battery. In order to make the estimation more accuracy, the parameters of the discharge qualifications and the temperature are adopted aimed to the characteristic of the lithium-ion battery. Compared to kalman method, the calculation of this method is simpler. The simulating results are more accuracy by the correction of the parameters.Firstly, the battery-manage system and the basic knowledge of the soc estimation are introduced; Secondly, based on the acknowledging the mechanism of the lithium-ion battery reaction and the working characteristic, according to the parameters, the curves are investigated, which illustrated the relationship between the battery capability and the temperature or the discharge qualification. The parameters are analyzed by matlab. After the construction of the math model and correcting parameters, the A-H measurement method is adopted to conduct soc estimation. Moreover, the simulating results are discussed. The advantage and the disadvantage of the A-H measurement method are analyzed. The effects of the new parameters are also discussed. At last the realized version of the program and the discussion results are given.