Metal Particle Foreign Matter as a Hidden Driver of Battery Aging: A Defect-Informed Modeling Study

Area of Science:

• Materials Science
• Electrochemistry
• Battery Engineering

Background:

• Metal particle foreign matter (MPFM) is a critical defect in lithium-ion battery manufacturing.
• MPFM compromises battery reliability and lifetime consistency.
• Degradation pathways caused by MPFM are not fully understood.

Purpose of the Study:

• To develop a model quantifying MPFM-induced aging in lithium-ion batteries.
• To investigate the impact of MPFM on solid-electrolyte interphase (SEI) formation and lithium plating.
• To analyze the influence of MPFM characteristics on battery degradation.

Main Methods:

• Developed a microstructure-resolved electrochemo-mechanical model.
• Explicitly accounted for SEI formation and lithium plating on graphite and metallic inclusions.
• Performed parametric analysis on MPFM type, distribution, location, and size.

Main Results:

• MPFM causes negligible cell-level voltage changes but significant internal electrochemical perturbations.
• The metal-electrolyte interface accelerates plating-dominated degradation.
• Degradation severity depends on MPFM type (Al > Ni > Fe > Cu) and location, with smaller particles worsening the effect.

Conclusions:

• MPFM significantly impacts internal battery electrochemistry and accelerates degradation.
• Contamination-aware manufacturing and reliability assessments are crucial.
• Model provides insights into defect-informed process control strategies.