A method for estimating parameters of a lithium-ion battery variable time-scale model

Abstract

The invention relates to a parameter estimation method for variable time scale models of lithium ion batteries. The method is used for carrying out parameter estimation on quadratic equivalent circuit mathematic models of lithium ion batteries so as to respectively obtain time constants of large and small time scale links. The method comprises the following steps of: 1) determining time scale ranges of time constants corresponding to a small time scale link and a large time scale link in a quadratic equivalent circuit mathematic model of a lithium ion battery; 2) respectively estimating a time constant of the large time scale link and a time constant of the small time scale link; and 3) verifying the time constant of the large time scale link and the time constant of the small time scale link by adopting the time scale ranges so as to obtain final time constants. Compared with the prior art, the method provided by the invention has the advantages of being correct and reliable in calculation, carrying out sub-step identification and reducing the operand.

Description

technical field [0001] The invention relates to a parameter estimation method, in particular to a parameter estimation method of a variable time scale model of a lithium ion battery. Background technique [0002] As a key component, the power battery system has been used more and more in the fields of electric vehicles and electric energy storage. In the application process, a battery management system (Battery Management System, BMS) is required to estimate and monitor the parameters and state of the battery, and further use it for power estimation or life state estimation of the battery. In the existing research and application, the battery model is mostly based on the equivalent circuit model, and the parameters in the model are mostly obtained by offline calibration or online estimation. The off-line calibration method requires a large number of battery tests in advance, which takes a long time and a lot of work, and the parameters of the calibration are difficult to ad...

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Problems solved by technology

It can be known from the electrochemical theory that the internal reaction process of the battery mainly includes the charge transfer process with a small time constant and the diffusion process with a large time constant when the battery is in use. The two resistance-capacitance links in the equivalent circuit model represent these two processes respectively. The existing parameter estimation algorithms are not designed for different time scales of the process, which makes it difficult to guarantee the parameter estimation of the large time constant link, which limits the further application of the parameter information based on the battery model

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