A method for estimating state of charge of lithium battery with temperature compensation function

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 present invention belongs to the field of lithium battery charge and discharge technology, and in particular to a lithium battery charge state estimation method having a temperature compensation function. Background technique [0002] With the gradual depletion of coal and oil and other fossil energy and people's environmental protection issues, electric vehicles supplied with power batteries as main energy supply, the advantages of high energy saving efficiency are increasingly valued. The rating of the monomer lithium battery product is 3.2V and 4.2V. If the voltage and capacity required to meet the power battery, a large number of unit batteries need to be used in parallel into groups. The power battery is one of the most important components of the electric vehicle, requiring its operating state to perform real-time precise detection. The charge state SOC (State of Charge) is one of the most critical technical parameters of the lithium battery, and ...

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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