UW-Madison Study Debunks ‘Absolute Safety’ Myth of Solid-State Batteries, Highlights Persistent Fire Risk

August 2, 2026

Unknown USA

Overview

Engineers at the University of Wisconsin-Madison reveal that while all-solid-state batteries offer significant safety advantages over conventional lithium-ion cells, they are not immune to ignition and combustion in severe accident scenarios. Despite eliminating flammable liquid electrolytes, the research indicates thermal runaway remains a possibility, driven by factors like high energy density and lithium metal anodes. This finding underscores the critical need for rigorous safety design and evaluation as next-generation battery technologies approach commercialization.

In Depth

Background

As the adoption of electric vehicles (EVs) accelerates globally, battery safety has emerged as a paramount concern for both consumers and regulatory bodies. Frequent fire incidents involving existing lithium-ion batteries often escalate into significant public safety issues, intensifying the drive for next-generation battery technologies. All-solid-state batteries (ASSBs) have long been hailed as the ‘ultimate solution’ to these safety concerns, promising a radical reduction in fire risk by replacing flammable liquid electrolytes with non-flammable solid counterparts. However, new research from the University of Wisconsin-Madison offers a realistic perspective, challenging overly optimistic expectations. Assistant Professor Eric Kazak, who led the research, stated, “Our research shows that as next-generation batteries start to become commercial products, they need to be seriously considered to be as safe as possible,” emphasizing the necessity for rigorous safety evaluation and design from the earliest stages of technological development.

Key Findings

Research conducted by engineers at the University of Wisconsin-Madison has revealed that while all-solid-state batteries offer potential safety improvements compared to existing liquid-electrolyte lithium-ion batteries, they cannot completely eliminate the risk of ignition and combustion under harsh conditions or in worst-case accident scenarios. This discovery challenges conventional assumptions about the absolute safety of all-solid-state batteries and emphasizes the need for even more stringent safety measures as they approach commercialization.

Technical Insights

All-solid-state batteries are widely anticipated to significantly reduce the risk of thermal runaway and fire by replacing flammable organic liquid electrolytes with non-flammable solid electrolytes. However, this study demonstrated that even lithium metal batteries utilizing solid electrolytes can experience thermal runaway under specific conditions, potentially leading to fire. The researchers point out that the lower heat capacity of solids compared to liquids, combined with the high energy density of all-solid-state batteries and the inherent presence of lithium metal anodes, contributes to intrinsic hazards. This suggests that merely removing liquid electrolytes does not guarantee ‘absolute’ safety; mechanisms for thermal runaway can still exist if internal short circuits within the solid electrolyte, external physical damage, or overcharging interact in a complex manner. This analysis highlights that further optimization of material selection, cell structure, and battery management systems (BMS) is essential for the safety design of all-solid-state batteries.

Strategic Implications & Outlook

This study presents new considerations for safety design to all-solid-state battery developers. Moving forward, the selection of materials (e.g., more thermally stable solid electrolytes), cell structural design (enhancing internal short-circuit prevention mechanisms), and the development of advanced battery management systems (capable of detecting thermal runaway precursors and preventing them proactively) will become even more critical. While all-solid-state batteries remain a promising technology, ensuring their true safety and reliability requires collaboration between academia and industry to establish comprehensive risk assessment and robust safety design standards. This collaborative effort is expected to lead to the realization of truly safe, next-generation batteries that consumers can trust and utilize with confidence.

Source: https://pubs.rsc.org/ta/article/doi/10.1039/d6ta03047e/1283229/Fire-safety-profiles-of-lithium-metal-batteries?searchresult=1

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