Temperature-compensation-function-contained method for estimating charge state of lithium battery

Abstract

Provided in the invention is a temperature-compensation-function-contained method for estimating the charge state of a lithium battery. On the basis of the second-order RC network equivalent circuit model of all single batteries, a temperature model of all single batteries of a lithium battery group is established by combining the thermodynamic first rule, the Fourier's law and Newton's law of cooling, wherein the temperature model includes internal heat generated by all single batteries, convection and heat exchange between all single batteries and an ambient environment, convection and heatexchange among all single batteries, and conduction and heat transfer between all single batteries. Because of establishment of the temperature model, the estimation precision of internal parameters,including the open circuit voltage, internal resistance, polarization internal resistance, and polarization voltage, of the equivalent circuit model of all single batteries is improved; and on the basis of the unscented Kalman filter algorithm, the SOC of each single battery is estimated and the estimation precision of the SOC of each single battery is improved by combining the UKF of the temperature model. Therefore, the technical means and support basis having the certain reference value can be provided for the estimation method research of the SOCs of all single batteries in the lithium battery group.

Description

technical field [0001] The invention belongs to the technical field of charging and discharging of lithium batteries, and in particular relates to a method for estimating the state of charge of a lithium battery with a temperature compensation function. Background technique [0002] With the gradual depletion of fossil energy such as coal and petroleum and people's continuous attention to environmental protection issues, electric vehicles that use power batteries as the main energy supply have attracted more and more attention due to their advantages of zero pollution and high energy saving efficiency. The rated voltage of single lithium battery products is 3.2V and 4.2V. If you want to meet the voltage and capacity required by the power battery, you need to connect a large number of single batteries in series and parallel to form a group. As one of the core components of electric vehicles, power batteries require real-time and accurate detection of their operating status. ...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the current lithium battery state of charge estimation algorithm's dependence on the initial value, the estimation results are easy to diverge, and the influence of temperature on the accuracy of lithium battery state of charge estimation is not considered, a lithium battery charge with temperature compensation function is proposed. state estimation method

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