# Non-invasive Current Density Imaging of Lithium-Ion Batteries

**Authors:** Mark G. Bason, Thomas Coussens, Matthew Withers, Christopher Abel, Gary Kendall, Peter Kruger  
**arXiv:** [2103.03358](https://arxiv.org/abs/2103.03358)  
**Date:** 2021-01-29  
**Summary page:** https://www.summarizepaper.com/en/paper/2103.03358v1/

## Key points

- Transition to electric vehicles relies on high-performing batteries
- Need for diagnostic tools for optimal battery use and innovative designs
- Introduction of sensitive magnetometry for monitoring internal battery processes
- Ability to map current flow within battery cells with high accuracy using magnetometry
- Importance of non-invasive measurement techniques for monitoring battery health and state of charge
- Multi-scale characterization techniques are crucial for understanding lithium-ion batteries and driving innovation towards safer and more efficient energy storage solutions

## Summary

The rapid transition from fossil fuel-powered vehicles to electric vehicles hinges on the development of high-performing, energy-dense batteries. This requires a wide array of diagnostic and monitoring tools for optimal use of current battery cells and the creation of innovative battery chemistries and designs. While imaging techniques can provide structural and chemical information, non-invasive methods for monitoring internal battery processes are limited. In this study, researchers introduce sensitive magnetometry as a tool to detect a battery cell's internal current distribution from outside the cell. By using an array of sensors to image the magnetic field during cycling of a pouch cell between charge states, they were able to accurately map the current flow within the cell with enough resolution to detect deviations around areas of high current density at a percent-level accuracy. This breakthrough paves the way for rapid and reliable assessment throughout all stages of a battery's life cycle. Additionally, various non-invasive measurement techniques such as electrochemical acoustic methods, magnetic susceptibility analysis, and magnetic tomography have been successfully used in other studies to monitor changes in state of charge (SoC) and state of health (SoH) in batteries. These advancements highlight the importance of multi-scale characterization techniques in understanding electrochemical devices like lithium-ion batteries. Ultimately, this drives innovation in the field towards safer and more efficient energy storage solutions.