Aerogel Intumescent Fire Protection Coating: Addressing Battery Safety Challenges in the New Energy Industry

With the rapid expansion of electric vehicles and energy storage systems, battery safety has become a critical concern for the new energy industry. Fires caused by lithium-ion battery thermal runaway are increasingly recognized as one of the most serious risks in modern battery systems.

Conventional flame-retardant materials can only achieve self-extinguishing behavior once the external flame source is removed, but they are often unable to effectively block heat transfer during extreme thermal events. At the same time, thick insulation solutions can negatively affect system weight, energy density, and manufacturing efficiency. As a result, there is growing demand for advanced fire protection materials capable of providing efficient thermal barriers without compromising design flexibility.

Aerogel intumescent fire protection coatings are emerging as an effective solution to address these challenges.

Key Safety Challenges in Battery Systems

One of the most critical risks in lithium-ion battery systems is thermal runaway propagation. When a single battery cell fails, it can release extremely high temperatures exceeding 1000 °C. Without effective thermal barriers, this heat can quickly spread to neighboring cells, triggering a cascading failure throughout the battery pack. In densely deployed energy storage systems, such chain reactions may escalate into large-scale fire incidents affecting entire installations.

Traditional fire protection materials also present several limitations. Many conventional solutions are either bulky or offer limited thermal insulation performance. Some polymer-based flame-retardant materials rely on organic additives that may release toxic smoke when exposed to fire. Although these materials may meet basic certification requirements, they often struggle to provide reliable protection under severe thermal conditions.

Engineering integration is another challenge. Battery packs and energy storage enclosures typically feature complex structures with reinforced ribs and irregular geometries. Rigid fireproof boards are difficult to integrate into these designs, while ordinary coatings may crack or detach under vibration, thermal expansion, or battery swelling. At the same time, materials used in battery systems must meet strict requirements for electrical insulation and environmental compliance.

Aerogel Intumescent Coating Technology

The AG-CF03 aerogel intumescent fire protection coatings integrate the ultra-low thermal conductivity of nano-structured SiO₂ aerogel with an advanced intumescent flame-retardant system.

Using aerogel as the core filler combined with expansion agents and inorganic flame retardants, the coating forms a multifunctional protective layer capable of delivering three key benefits: ultra-thin thermal insulation, active fire-resistant expansion, and excellent structural adaptability.

Key Performance Advantages

One of the most significant advantages of this coating is its high efficiency at minimal thickness. A coating layer of only 0.5–2 mm, with 1 mm recommended, can provide substantial fire resistance. Tests show that a 1 mm coating can withstand high-temperature flame exposure for up to one hour. After 30 minutes of direct flame exposure, a 0.5 mm coating maintains a backside temperature below 265 °C, while a 1.16 mm coating can achieve a fire resistance duration of over 65 minutes. This performance helps effectively slow heat transfer and reduce the risk of thermal runaway propagation.

The coating also incorporates an intumescent fire protection mechanism. When exposed to fire, the material expands and forms a porous yet dense carbonized insulation layer. This expanded structure acts as a thermal barrier that blocks flame penetration and significantly reduces heat conduction. Unlike materials that only achieve UL94 V-0 self-extinguishing performance, the coating maintains structural integrity during prolonged high-temperature exposure, providing valuable time for evacuation and fire suppression.

Another important advantage is its ease of application. The coating can be applied by brushing, spraying, or rolling, allowing it to adapt easily to complex battery pack or energy storage cabinet structures, including reinforced ribs and curved surfaces. It dries to the touch within 2–4 hours and provides strong adhesion with bonding strength exceeding 1.5 MPa and cross-cut adhesion rated at Grade 1. The coating also demonstrates strong resistance to vibration and structural expansion, ensuring long-term reliability without cracking or peeling. In addition, the surface finish is smooth and uniform, with customizable color options available.

From a safety perspective, the coating meets multiple technical requirements for battery systems. It provides excellent electrical insulation performance, with resistance exceeding 500 MΩ at 1000 VDC and leakage current below 2 mA at 3000 VDC. The formulation primarily uses inorganic flame retardants and does not release toxic smoke during fire exposure. It also complies with environmental standards such as RoHS and REACH and is designed to support product lifecycles of 8–10 years.

Testing data:

Typical Application Scenarios

In electric vehicle battery packs, the coating can be applied to the battery enclosure, top cover, or bottom protection plate. Internally, it helps slow the spread of thermal runaway between cells, providing additional time for passenger evacuation. Externally, it can also protect battery systems from mechanical impact, road debris, or external fire sources.

For stationary energy storage systems, the coating can be applied to the metal shell of energy storage cabinets or containerized systems. By delaying structural failure of the enclosure and limiting flame propagation between adjacent cabinets, the coating helps prevent single-cabinet failures from escalating into large-scale incidents. This provides critical time for firefighting operations and system isolation, reducing potential economic losses.