Mass-Spring-Damping Theory Based Equivalent Mechanical Model for Cylindrical Lithium-ion Batteries under Mechanical Abuse

Abstract

An equivalent mechanical model with the equivalent physical meaning of mass-spring-damping is proposed for cylindrical lithium-ion batteries through experiments and theory. The equivalent mechanical model of a cylindrical lithium-ion battery consists of a spring-damping parallel unit. Therefore, a spring-damping parallel unit connecting a damping unit in series is selected to construct the constitutive characteristics of the battery under mechanical abuse. Comparison results show that the equivalent mechanical model can more effectively describe the mechanical properties of the batteries than most cubic fitting models, of which the average relative error of the equivalent mechanical model under different states-of-charge is less than 6.75%. Combined with the proposed equivalent mechanical model, the failure process of the batteries was simulated and analyzed using LS-Dyna and HyperWorks. Under rigid rod tests, failure occurred at the core and bottom of the batteries; under hemispherical punch tests, failure occurred at the core and top, consistent with the experimental results. The average prediction error for the failure displacement under different abuse conditions is less than 4% in the simulations. The equivalent mechanical model requires only a few parameters and can be recognized easily. In the future, the model can be used in safety warning devices based on mechanical penetration.

A Comparative Study of Fractional Order Models on State of Charge Estimation for Lithium Ion Batteries

“…As a time-variant electrochemical power source, management of lithium ion batteries has drawn much attention. In particular, the accurate estimation of state of charge (SOC), which directly decides the driving distance and power performance, is one of the most indispensable tasks of battery management systems (BMSs) [1,2].…”

A comparative study of fractional order models on state of charge estimation for lithium ion batteries

“…As a time-variant electrochemical power source, management of lithium ion batteries has drawn much attention. In particular, the accurate estimation of state of charge (SOC), which directly decides the driving distance and power performance, is one of the most indispensable tasks of battery management systems (BMSs) [1,2]. SOC is generally defined as the ratio between the available capacity and maximum capacity [3].…”

“…Five fractional order models reported in the literature.The voltage Uc across a R//CPE branch and Uw across a Warburg element are governed by(2) …”