Homogenized modeling methodology for 18650 lithium-ion battery module under large deformation.

Liang Tang,Pengle Cheng,Jinjie Zhang,Xiaosong Hu

doi:10.1371/journal.pone.0181882

Abstract

Effective lithium-ion battery module modeling has become a bottleneck for full-size electric vehicle crash safety numerical simulation. Modeling every single cell in detail would be costly. However, computational accuracy could be lost if the module is modeled by using a simple bulk material or rigid body. To solve this critical engineering problem, a general method to establish a computational homogenized model for the cylindrical battery module is proposed. A single battery cell model is developed and validated through radial compression and bending experiments. To analyze the homogenized mechanical properties of the module, a representative unit cell (RUC) is extracted with the periodic boundary condition applied on it. An elastic–plastic constitutive model is established to describe the computational homogenized model for the module. Two typical packing modes, i.e., cubic dense packing and hexagonal packing for the homogenized equivalent battery module (EBM) model, are targeted for validation compression tests, as well as the models with detailed single cell description. Further, the homogenized EBM model is confirmed to agree reasonably well with the detailed battery module (DBM) model for different packing modes with a length scale of up to 15 × 15 cells and 12% deformation where the short circuit takes place. The suggested homogenized model for battery module makes way for battery module and pack safety evaluation for full-size electric vehicle crashworthiness analysis.

Highlights

With the strong support from the government [1] and major technology breakthrough for lithium-ion batteries (LIBs) [2, 3], electric vehicles (EVs) have been witnessed to boom over the past recent years [4,5,6]
The dynamic behavior [27] and SOC effect [28] of the battery have been studied and the results suggested that higher SOC leads to higher structure stiffness
Experiments, homogenized equivalent battery module (EBM) model and corresponding detailed battery module (DBM) model were conducted on the case for the cubic dense packing mode, i.e. θ = π

Summary

Introduction

With the strong support from the government [1] and major technology breakthrough for lithium-ion batteries (LIBs) [2, 3], electric vehicles (EVs) have been witnessed to boom over the past recent years [4,5,6]. The major reason for LIBs to become the primary choice for EVs is due to the combination advantage of high energy/power density, lightweight, and safety [6, 7]. The battery management system plays an important role in maintaining battery lifetime without unduly sacrificing its performance. Some key technologies of battery management system that monitor the unmeasurable internal states of the battery have been extensively studied [11,12,13,14].

Methods

Results

Conclusion