II. What role does aerogel play in EV battery safety protection, and how does it work?
1. Thermal Insulation – Blocks heat transfer during thermal runaway, preventing cascade failure.
2. Fire Resistance – Inorganic and non-combustible, forms a stable skeleton barrier against flames.
3. Lightweight – Much lighter than mica or ceramic fiber, minimizing pack weight.
4. Design Flexibility – Available as blankets, pads, coatings, or composites, adaptable to multiple pack locations.
5. Operational Stability – Buffers daily thermal stress, keeping cells in the safe range and extending cycle life.
6. Full Lifecycle Protection – Under compression, aerogels exhibit lower thermal conductivity and good resilience, ensuring long-term protection even in the late stages of battery life.
Working Principles
1. Nanoporous Thermal InsulationPorosity up to 80–99%, pore sizes (2–50 nm) smaller than the mean free path of air molecules.
· Strongly suppresses:
o Gas conduction
o Solid conduction
· Convection
Result: Thermal conductivity (0.013–0.020 W/m·K) lower than still air.
2. Delay of Thermal Runaway Propagation
o Aerogel pads localize heat within the failed cell.
o Delays propagation for several minutes, allowing BMS and safety systems to respond.
3. Inorganic Fire-Resistant Barrier
o Silica aerogels do not burn; at high temperature, they form a stable silica skeleton.
o Acts as a "firewall", blocking flame and heat spread.
4. Compression-Enhanced Insulation
o Unlike conventional materials, aerogels become even better insulators under compression.
o Maintains or improves insulation despite cell swelling or long-term mechanical stress.
