Method for estimating open-circuit voltage of lithium-ion battery based on temperature input, and system

Abstract

The invention provides a method for estimating the open-circuit voltage of a lithium-ion battery based on temperature input, and a system. The method comprises the steps that step one, a to-be-determined open-circuit voltage estimating equation based on temperature input is deduced according to a gas-liquid dynamics model; step two, estimating equation parameters are identified according to experimental data and substituted into the to-be-determined open-circuit voltage estimating equation in the step one to obtain a complete open-circuit voltage estimating equation; and step three, the open-circuit voltage estimating method based on temperature input is designed according to the complete open-circuit voltage estimating equation. According to the method, a state equation of the gas-liquiddynamics model contains the influence of the temperature on the battery open-circuit voltage, and a temperature compensation coefficient and an empirical formula do not need to be introduced; experimental data required for parameter recognition are few, and model parameters are easy to identify; the sampling temperature at the previous time and the sampling temperature at the current time are input into the model, and more temperature information is reflected in the process of estimating the open-circuit voltage of the battery; and as for the equation for estimating the open-circuit voltage, the sampling error can be eliminated through iteration of the equation, an initial value is not needed, and the estimation accuracy is high.

Description

technical field [0001] The invention belongs to the field of battery management systems, in particular to a method and system for estimating the open-circuit voltage of a lithium-ion battery with temperature input. Background technique [0002] According to the latest estimate of the American Petroleum Industry Association, the unexploited crude oil reserves on the earth are less than 2 trillion barrels, which can be exploited by human beings for no more than 95 years. Automobiles account for more than one-third of total oil consumption. Countries around the world have made great efforts to realize the energy transformation of automobiles. Among them, making fuel vehicles electrified is one of the important choices. However, the on-board lithium battery has a large charging and discharging window, and the charging and discharging process of the battery shows extremely complex nonlinear characteristics, and the available capacity of the battery is greatly affected by the chan...

AI Technical Summary

Problems solved by technology

However, the intelligent algorithm needs to do a lot of calculations, and the final equivalent circuit model still needs to be coupled with the temperature. It is also difficult to realize real-time estimation on the vehicle MCU.

[0004] In summary, only relying on the existing battery model is far from meeting the needs of practical applications. There is an urgent need for a model that can more accurately reflect the relationship between temperature and battery performance, and more accurately describe the nonlinear characteristics and structure of the battery charge and discharge process. Simple, less computationally intensive analytical model and method for estimating open-circuit voltage

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