Fighting Thermal Runaway: How High-Performance Thermal Pads Become the Lifeline of New Energy Battery Packs

As the new energy industry accelerates, battery safety remains the cornerstone of progress. Whether in electric vehicle (EV) battery packs or large-scale energy storage systems (ESS), thermal runaway poses the most dangerous threat. A single cell failure is manageable—but a chain reaction can trigger an entire module or system to ignite within seconds. In this race against time, the high-performance thermal insulation pad has become more than just a support material; it is the last and most critical lifeline that stands between stability and disaster.

The Deadly Chain Reaction of Thermal Runaway—and the “Firewall” Role of Thermal Pads

The essence of thermal runaway lies in the imbalance between heat generation and dissipation. When internal short-circuiting causes rapid temperature rise—often exceeding 800°C—electrolytes combust and active materials decompose, triggering chain exothermic reactions. Without intervention, heat spreads through conduction and radiation, rapidly igniting neighboring cells and engulfing the entire pack.

At this critical moment, the battery thermal insulation pad serves as a firewall: delaying heat transfer between cells, allowing the Battery Management System (BMS) to issue alarms, activate cooling systems, and, in EVs, provide a crucial five-minute escape window for passengers—or, in energy storage units, enough time for fire suppression systems to engage.

Why Ordinary Materials Fail: Extreme Requirements of Battery Thermal Pads

Under such extreme thermal conditions, conventional insulation materials fall short. A dedicated thermal barrier pad must meet multiple demanding criteria:

• Ultra-low thermal conductivity: The foundation of insulation performance. Even under high temperatures, the pad must block heat transfer effectively. Aerogel thermal pads are the top-tier choice, offering conductivity as low as 0.015–0.025 W/m·K at room temperature while maintaining stability under heat.
• Superior heat resistance and flame retardancy: Materials must withstand 800–1000°C exposure without melting, burning, or sustaining flames, forming a carbonized layer that strengthens insulation under fire.
• Integrated cushioning and insulation: Beyond thermal protection, pads must absorb mechanical stress from cell expansion and maintain tight adhesion throughout the battery’s life cycle. Silicone foam pads are widely used for their compression resilience and long-term stability.
• Lightweight and stable: To support EV range and durability, materials must balance strength and weight, while resisting chemical corrosion and degradation from electrolytes.

Strategic Application: How Thermal Pads Protect Battery Modules

Within EV battery pack design, thermal pads are strategically placed at key locations:

• Between battery cells: The most crucial position. By isolating each cylindrical, prismatic, or pouch cell, the pad prevents direct heat transfer—like firewalls between explosive chambers.
• Between battery modules: Preventing runaway propagation from one module to another within the pack.
• Between the upper cover and cells: Protecting the battery lid and pressure relief valves from direct flame impact during runaway events.
• Inside energy storage cabinets: In large-scale systems, multi-layered insulation boards and fireproof cotton create a tiered protection system that contains damage within minimal zones.

Material Evolution: From Basic Insulation to Integrated Safety Systems

Earlier solutions relied on fiberglass or ceramic fiber sheets. Today, material innovation drives performance to a new level:

• Aerogel composite insulation: The star of modern thermal runaway protection, offering unmatched performance in limited space—ideal for high-energy-density battery packs.
• Expandable thermal materials: These intelligent materials expand and carbonize upon high-temperature exposure, forming porous protective layers that drastically reduce thermal conductivity in real time.

Conclusion

As battery energy density and system scale continue to grow, preventing thermal runaway is no longer optional—it’s an uncompromising baseline for safety. Choosing the right thermal insulation pad isn’t just a material decision; it’s a commitment to system integrity and user safety.

From aerogel insulation pads to silicone foam thermal barriers, these silent protectors stand guard between every cell—absorbing stress, isolating heat, and, in crisis, becoming the most reliable firewall in the race against time.