A research team from Nanjing Tech University has developed a breakthrough silica aerogel-based insulation sheet designed to prevent “thermal runaway” in lithium-ion batteries. Capable of withstanding temperatures up to 1300°C, this new material represents a significant leap in electric vehicle (EV) safety technology.
Solving the Thermal Runaway Problem
In high-density battery packs, a single cell failure can trigger a chain reaction known as thermal runaway. During this event, temperatures spike violently and rapidly, causing heat to transfer to neighboring cells and leading to catastrophic battery fires.
Existing aerogel solutions have historically struggled to contain these spikes, typically functioning only up to 300°C or 650°C. Because actual cell combustion can reach temperatures between 650°C and 1000°C, previous materials often failed when they were needed most.
The new silica aerogel sheet addresses this gap:
– Extreme Heat Resistance: It can withstand temperatures up to 1300°C.
– Proven Isolation: In tests, a mere 2.3 mm sheet kept the opposite side below 100°C even after being exposed to 1000°C for five minutes.
– Extended Protection: The material can maintain thermal isolation for up to two hours, providing a critical window for safety systems to engage or for passengers to exit a vehicle.
Engineering for Durability and Scale
Creating a material that is both highly insulating and physically resilient is a difficult engineering feat. The researchers focused on two primary technical hurdles:
1. Structural Integrity and Elasticity
Aerogels are nanoporous structures that are approximately 99% air, which makes them excellent insulators but notoriously brittle. To make the material practical for EVs—where battery cells constantly expand and contract during use—the team engineered the sheet to achieve over 90% elastic compression without losing its structural stability.
2. Industrial Scalability
To move from a laboratory concept to mass production, the team optimized the supercritical CO₂ drying process. By implementing a solvent recovery system that reuses over 99.5% of ethanol, they have successfully reduced raw material costs by more than half, making large-scale manufacturing economically viable.
Market Adoption and Strategic Context
The technology is already seeing rapid integration into the supply chains of major industry players, including CATL, BYD, Sungrow, and Xiaomi. While its primary immediate use is in the EV sector, its high-temperature tolerance also opens doors for applications in aerospace and heavy industrial environments.
This development is part of a broader trend in the Chinese energy sector, driven by the strategic goals of the nation’s “15th Five-Year Plan,” which prioritizes advanced materials and new energy technologies. As the industry moves toward larger battery capacities—such as Svolt’s recent 80 kWh PHEV battery—the demand for sophisticated safety components like this aerogel “firewall” will only increase.
This breakthrough shifts aerogel insulation from a niche, high-end luxury component toward a standard safety requirement for the next generation of mass-market electric vehicles.
Conclusion
By bridging the gap between current insulation capabilities and the extreme temperatures of battery combustion, this new material provides a critical layer of defense against vehicle fires. Its combination of high heat resistance, elasticity, and low production cost positions it to become a cornerstone of safer, more reliable EV battery architecture.
