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

Area of Science:

• Computational mechanics
• Materials science
• Automotive engineering

Background:

• Accurate lithium-ion battery module modeling is crucial for electric vehicle (EV) crash safety simulations.
• Detailed cell-by-cell modeling is computationally expensive, while simplified models lack accuracy.
• A need exists for efficient and accurate homogenized models for battery modules.

Purpose of the Study:

• To propose a general method for establishing a computational homogenized model for cylindrical lithium-ion battery modules.
• To develop a validated single battery cell model for use in homogenization.
• To enable accurate and efficient crashworthiness analysis of EV battery packs.

Main Methods:

• A single battery cell model was developed and validated via radial compression and bending experiments.
• A representative unit cell (RUC) with periodic boundary conditions was used to determine homogenized mechanical properties.
• An elastic-plastic constitutive model was established for the homogenized equivalent battery module (EBM) model.
• The EBM model was validated against detailed battery module (DBM) models for different packing configurations.

Main Results:

• The validated single cell model accurately represented cell behavior.
• The homogenized EBM model showed good agreement with DBM models up to a scale of 15x15 cells.
• The model accurately predicted behavior during 12% deformation, a critical point for short circuits.

Conclusions:

• The proposed computational homogenized model offers an efficient and accurate approach for battery module simulation.
• This method significantly reduces computational cost for EV crash safety analysis.
• The validated model facilitates improved battery module and pack safety evaluations in automotive design.