Lithium battery model considering nonlinear capacity effect

Abstract

The invention discloses a lithium battery model considering a nonlinear capacity effect, which comprises a state of charge part and a V-I characteristic part, the state of charge part comprises a resistor Rdischarge, a resistor R2, a capacitor C1 and a capacitor C2, the V-I characteristic part comprises a resistor Rohmic, a resistor RSEI, a resistor RCT, a resistor RZw, a capacitor CSEI and a capacitor CDL, one end of the resistor Rdischarge is connected with the resistor R2, the capacitor C1 and a current side of an SOC module, and the other end of resistor R2 is connected to capacitor C2. According to the invention, a hybrid equivalent circuit model is established for the lithium ion battery, the model is divided into a state-of-charge part and the V-I characteristic part, and the function relationship between the open-circuit voltage of the battery and the SOC is used as a connection bridge. The two parts in the model can reflect the characteristics of the lithium ion battery in all aspects, and the model is a comprehensive equivalent circuit model.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a lithium battery model considering nonlinear capacity effects. Background technique [0002] Energy storage technology is widely used in power systems, electric vehicles and other fields, and has become a research hotspot today. Among many energy storage carriers, lithium-ion batteries have received a lot of attention due to their advantages such as large specific energy, long cycle life, small self-discharge, no memory effect, and environmental friendliness. To effectively simulate a real Li-ion battery, a proper battery model is essential. The model needs to be able to reflect the state of charge of the battery, to simulate the output voltage and current curve of the battery, and some other inherent characteristics of the battery. At the same time, the model must be low in complexity and high in accuracy. [0003] For this reason, experts and scholars have done a lot of re...

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Problems solved by technology

[0005] The KiBaM model is an intuitive battery model that can describe the nonlinear capacity effect of the battery, which is helpful for the estimation of the battery SOC and the prediction of the running time. However, it cannot describe the dynamic V-I characteristics of the battery, nor can it be integrated with other circuits or systems. co-simulation

Proctor's equation can make up for the deficiency of the KiBaM model and help to quantitatively describe the nonlinear capacity effect of the battery. However, the equation is not very accurate in fitting the lithium-ion battery curve

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