Lithium battery charge state estimation method for battery capacity decoupling

Abstract

The invention discloses a lithium battery charge state estimation method for battery capacity decoupling. The estimation method comprises the steps of battery model parameter online identification, convex optimization cost function design and Newton method cost function solving. The method comprises the following steps: firstly, obtaining a discretization recursion formula by using a battery model, and carrying out online identification on parameters of a battery by using a least square method with a forgetting factor to obtain the parameters of the battery; and then, on the premise that the battery capacity is not used, a cost function is constructed by using an SOC filter and a discrete recursion formula, so that the cost function is always a convex function during state estimation. And finally, solving the cost function by using a Newton method to obtain a recursive formula of the state of charge of the battery. The lithium battery state-of-charge estimation method for battery capacity decoupling provided by the invention does not depend on battery capacity parameters, realizes accurate state-of-charge estimation, and can also quickly track the true value of the state-of-charge of the battery when the initial point is inaccurate.

Description

technical field [0001] The invention relates to the technical field of lithium battery state of charge estimation, in particular to a lithium battery state of charge estimation method with battery capacity decoupling. Background technique [0002] With the development of new energy technologies and electric vehicles, lithium-ion batteries are widely used due to their high energy density, light weight and long life. However, the safety and reliability of lithium batteries are still the main challenges in commercial use. The state of charge of a lithium-ion battery is one of the important parameters of battery operation, and accurate estimation of the state of charge is an important guarantee for the safe and stable operation of the battery. [0003] The state of charge cannot be directly obtained by measurement. The traditional method of estimating the state of charge generally uses the ampere-hour integration method and the Kalman filter method. These two methods are easy ...

AI Technical Summary

Problems solved by technology

However, battery capacity is highly correlated with battery life, which leads to inaccurate lithium battery state of charge estimation in the case of inaccurate battery capacity.

Images