Understanding Thermal Runaway and Lithium-Ion Battery Transport Risks

Lithium-ion batteries have revolutionized technology, powering everything from computers and smartphones to power tools and electric vehicles. However, if damaged or misused, these energy-dense cells can pose significant safety risks, particularly during transport. One of the biggest concerns is thermal runaway, a chain reaction that can lead to fires, explosions, and hazardous gas release.

To ensure safe transportation, especially via air, regulators and industry experts have been working to develop stringent safety measures. One of the most significant efforts is led by the SAE G27 Lithium Battery Packaging Performance Committee, which focuses on lithium-ion battery packaging standards to mitigate thermal runaway risks.

In this article, we’ll explore what thermal runaway is, why it’s a serious issue, and how the G27 Committee is working to improve transport safety.

What is Thermal Runaway?

Thermal runaway is a self-sustaining reaction that occurs when a lithium-ion battery overheats uncontrollably. It can be triggered by:

• • External heat exposure (such as fire or extreme temperatures).
• • Physical damage (crushing, puncturing, or dropping).
• • Internal short circuits (due to manufacturing defects or aging).
• • Overcharging or over-discharging, causing instability within the battery.

Once thermal runaway begins, the battery releases significant amounts of heat and gas, which can lead to ignition, explosions, and even chain reactions that affect nearby batteries. This is particularly dangerous when lithium-ion batteries are shipped in bulk.

Real-World Incidents That Raised Safety Concerns

Several high-profile incidents have highlighted the dangers of thermal runaway in lithium-ion batteries:

• • Cargo plane fires – Multiple aircraft incidents have been linked to lithium-ion battery shipments. In some cases, thermal runaway caused fires that overwhelmed the plane’s fire suppression systems.
• • Consumer product recalls – From smartphones to electric vehicles, defective lithium-ion batteries have been responsible for product recalls due to fire hazards.
• • Warehouse explosions – Storage facilities containing large quantities of lithium-ion batteries have experienced fires due to unchecked thermal events.

These incidents have prompted regulators, including the International Civil Aviation Organization (ICAO) and the Federal Aviation Administration (FAA), to implement stricter lithium-ion battery transport guidelines.

SAE G27 Lithium Battery Packaging Performance Committee’s Approach to Addressing Thermal Runaway

The SAE G27 Committee was established to develop a performance-based standard for lithium-ion battery packaging, including:

• • Testing packaging solutions to ensure they can contain a thermal runaway event.
• • Evaluating fire resistance of materials used in battery transport containers.
• • Standardizing test methodologies so that results are consistent across different laboratories.

The goal is to create packaging that prevents fire from spreading in case of a battery failure—protecting both cargo and passengers.

The Role of State of Charge in Reducing Risk

To further reduce risks, ICAO introduced a 30% state-of-charge rule, requiring that lithium-ion batteries be shipped at or below 30% of their maximum charge. The reason behind this rule is:

• • Lower energy levels reduce the likelihood of thermal runaway.
• • Lower heat generation means that even if failure occurs, the reaction will be less severe.
• • Increased safety margins for air transport, where battery containment is critical.

However, this rule alone is not enough to guarantee safety—hence the need for better packaging solutions.

Future Considerations for Battery Transport Safety

The industry is moving toward:

• • More advanced fire-resistant packaging.
• • New testing protocols for different types of lithium batteries (pouch, prismatic, and cylindrical cells).
• • Expanded regulations that include thermal resistance and flame resistance testing.

With continued research and collaboration, the G27 standard will play a vital role in ensuring lithium battery safety worldwide.

Final Thoughts

Thermal runaway risk remains one of the biggest challenges in lithium-ion battery transport. While regulatory measures like the 30% state-of-charge rule help, they do not eliminate the risk. That’s why the SAE G27 Lithium Battery Packaging Performance Committee is focused on creating reliable, tested, and standardized packaging that can contain thermal events.

As lithium-ion battery usage continues to grow, these advancements will be critical in preventing accidents and ensuring safe global transport.