Revolutionizing battery safety: magnetic fields unlock foolproof ID for electric vehicles' power packs

Research Background

As the world races toward carbon neutrality—think Japan's 2050 goal and global bans on gas-guzzling cars by 2035-2040—electric vehicles (EVs) are surging ahead, slashing emissions and transforming transportation. But this boom in lithium-ion batteries (LIBs), the high-energy hearts of EVs, smartphones, and more, brings a hidden danger: counterfeit or low-quality non-OEM batteries slipping into the mix. Reports highlight fires and explosions from these shady substitutes, especially in e-bikes and cameras, where overcharging or degradation turns them into ticking time bombs. Traditional safeguards like barcodes or IC chips? Easily faked or swapped. Enter a game-changing idea: harnessing the invisible magnetic fields generated by the batteries themselves during charge-discharge cycles. Building on prior nondestructive tech for spotting battery faults, this research pioneers magnetic analysis to authenticate LIBs right onboard vehicles, ensuring safety without invasive checks and paving the way for trustworthy EV adoption worldwide.

Results and Benefits

The study put prismatic LIBs—common in hybrid electric vehicles (HEVs)—under the magnetic microscope, measuring fields around cells with varying internal structures using sensitive sensors. Key findings? Distinct magnetic signatures emerged on the short sides of the cells, tied directly to differences in current collector shapes. For instance, simulations and real measurements showed clear variations in field distributions, reproducible even when scaling up to modules with two cells in series, where adjacent fields either amplified or canceled out predictably. Remarkably, identification boiled down to just two strategic sensor points per cell, with low variability and a linear relationship between current and magnetic field—meaning instant, proportional detection without complex setups.

Socially, these breakthroughs spell massive wins: fewer battery-related fires mean safer roads and homes, potentially saving lives and cutting insurance costs. For automakers and consumers, it guarantees genuine parts, boosting EV reliability and longevity—LIBs already outlast nickel-cadmium rivals with higher energy density. Environmentally, by curbing faulty battery waste, it supports sustainable tech cycles. Experimental data backs this: magnetic resonance imaging (MRI)-inspired methods detected defects noninvasively, while algorithms mapped 2D current distributions, proving the tech's precision for real-world applications like EVs and battery-powered gadgets.

Future Application Prospects

Imagine EVs that self-verify their batteries at startup, flashing a warning if a counterfeit sneaks in—stopping disasters before they start. This magnetic ID system could integrate into battery management systems (BMS), enhancing state-of-health (SOH) tracking alongside voltage and temperature monitoring. Scaling up, it applies to cylindrical cells in full EVs or even larger packs, with simulations adapting to varying cell distances or counts. Further research might blend machine learning for predictive field mapping or gas emission cross-checks for hybrid diagnostics. Practically, it could standardize safety protocols for global fleets, enabling traceability from factory to road and fostering innovations like vehicle-to-grid energy sharing, where authenticated batteries ensure grid stability. Ultimately, this refines EV ecosystems, making them smarter, safer, and more efficient for a greener future.

Conclusion

This innovative magnetic field approach shatters the limits of battery authentication, turning invisible forces into a robust shield against counterfeits and failures. By enabling onboard, nondestructive ID of LIBs, it not only fortifies EV safety but propels the electric revolution forward, ensuring a reliable, emission-free tomorrow for all.

Reference

Author: Aira Eto ^a, Yutaro Akimoto ^a, Keiichi Okajima ^a, Jun Okano ^b, Yukiko Onoue ^b

Title of original paper: Evaluation of lithium-ion batteries with different structures using magnetic field measurement for onboard battery identification

Article link: https://www.sciencedirect.com/science/article/pii/S2773153725000076

Journal: Green Energy and Intelligent Transportation

DOI: 10.1016/j.geits.2025.100257

Affiliations:

^a University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan

^b Honda R&D Co., Ltd, 4630 Ohjishimotakanezawa, Haga, Tochigi, Japan