In modern electric vehicle battery packs, to maximize energy density, battery cells are closely arranged, with the spacing between cells typically less than 1 millimeter. During normal operation, the voltage difference between these battery cells can exceed 400V, and thermal events can cause temperatures to rise above 150°C - in such cases, even minor insulation failures can lead to catastrophic short circuits.
The fundamental challenge lies in maintaining reliable electrical isolation between the batteries while minimizing the space dedicated to insulation materials and maintaining thermal management capabilities. This article presents 7 major application solutions, including composite shell materials for preventing delamination and burn-through, component insulation materials with mechanical and electrical protection, and anisotropic or directional heat transfer capabilities. These methods and others focus on balancing safety requirements and energy density targets in practical applications in mass-produced vehicles.

1. Aerogel multilayer insulation plates and composite barriers for preventing thermal runaway in electric vehicle (EV) battery systems
Thermal runaway in EV battery systems is one of the most significant safety challenges faced by manufacturers and designers. Traditional insulation materials such as silicone foam and mica plates may meet basic requirements, but they have significant limitations in mechanical toughness, cost-effectiveness, and structural integrity under extreme conditions.
A major advancement in addressing these limitations is the use of multilayer aerogel composite insulation plates with a sandwich structure. These insulation plates feature an aerogel core encapsulated between two protective layers, significantly enhancing compressive and flexural strength while maintaining excellent insulation performance. This encapsulation design serves two purposes: preventing the fragile aerogel core from generating dust and slowing material aging, thereby providing a more durable and easily integrated solution for EV battery packs. This method is detailed in the design of multilayer aerogel composite insulation plates, representing a significant improvement over traditional brittle insulation materials.
For applications requiring extreme temperature adaptability, a composite shell structure combines ceramic slurry-based insulation layers with silica aerogel insulation layers. The insulation layers feature a dual structure of ceramic slurry and silicon carbide fiber cloth, with excellent ablation resistance. The insulation layer is composed of nano-silica aerogel composite felts, offering superior insulation performance. This integrated design can withstand direct exposure to a 1300°C flame for 30 minutes without delamination or structural failure. Notably, its bending strength after ablation remains above 100 MPa, far exceeding that of traditional materials such as mica or ceramic fiber boards.
To address the dual challenges of insulation and lateral heat dissipation, aerogel flame-retardant sheets integrate two layers of aerogel-based insulation layers and ingeniously arrange copper foil or graphene conductive layers. The geometric arrangement of the conductive elements facilitates downward flow, effectively preventing vertical heat diffusion while maintaining lateral battery isolation. This structure combines fire resistance, directional heat management, and mechanical flexibility, and is lightweight and compact, suitable for high-density EV battery systems.

2. Aerogel + pre-oxidized silicon carbide felt insulation layer for preventing delamination and burn-through
As EV manufacturers continue to pursue higher energy density, effective thermal management becomes increasingly important. Phase change materials (PCM) represent an advanced passive thermal management method that surpasses traditional insulation materials.
The laminated ceramic composite material shell addresses these limitations through a heat-resistant layer made of silicon carbide fiber-reinforced ceramic slurry and an insulation layer composed of nano-silica aerogel and pre-oxidized silicon carbide felt. This dual-layer system maintains structural integrity and insulation properties even under 1300°C flame ablation for up to 30 minutes, minimizing material degradation.
The main advantage of the composite material shell lies in its light weight, scalability, and combination of high-temperature resistance and mechanical strength. Optimized ceramic slurry composition forms a cross-linked network, enhancing bending strength while preventing delamination and burn-through. Nano aerogel materials further reduce thermal conductivity, minimizing heat transfer to the internal battery modules. This structure also supports safe pressure relief during thermal accidents, thereby reducing the risk of chain failures while maintaining compatibility with existing manufacturing technologies.

3. Aerogel + Double-Layer Ceramicized Slurry System for Battery Pack Shell
The development of advanced insulation materials capable of maintaining thermal and mechanical integrity under extreme conditions has been driven by the risks of thermal runaway and short circuit propagation in high-capacity lithium-ion batteries.
For battery pack shells that need to balance thermal protection and structural strength, a multi-layer composite material shell structure can provide comprehensive protection. This design employs a double-layer ceramic slurry system composed of silicone resin and ceramic particles, coated on carbonized silicon fiber fabric to form a thermal insulation layer. The thermal insulation components made of nano-silica aerogel composite materials are placed beneath this protective layer. Together, these components form a barrier that can withstand direct exposure to flames of up to 1300°C for 30 minutes, with minimal material loss and structural performance maintained at the lowest level.
The composite material shell integrates ablative and mechanical reinforcement functions, enabling the battery pack to maintain bending strength even under extreme high-temperature conditions. Traditional materials would degrade or fail under such stress, while this solution can maintain mechanical strength over 100 MPa after ablation. The optimized slurry formulation reduces reliance on expensive silicon carbide fibers and improves process efficiency through solvent-stabilized dispersion, enabling the manufacture of lightweight, high-performance battery shells.

4. Aerogel Composite Materials for Mechanical and Electrical Isolation
The insulation materials in the battery pack must withstand extreme temperature changes while maintaining structural integrity. Generally, pads and gaskets between battery cells play this role, providing both mechanical stability and electrical isolation. Traditional pads typically fail to provide immediate insulation when physically damaged, leading to short circuits. Silica aerogel ceramic fiber composite materials solve the problems of traditional materials' susceptibility to ablation, fire, or uneven structures.
This composite material combines ceramic fiber fabric with silica aerogel matrix and is encapsulated with flame-retardant films or coatings. Strict dimensional tolerances and uniform density eliminate heat absorption voids, while the ultra-low thermal conductivity of the aerogel ensures minimal heat transfer between battery cells. This structure prevents heat diffusion while maintaining integrity under thermal stress.

5. Aerogel Insulation Layer/Plate for Battery Cell Top and Sides
In thermal management, the thermal insulation aluminum plate structure delays the spread of thermal runaway between battery cells by filling honeycomb layers (encased in aluminum plates) with silica aerogel powder. The low thermal conductivity of silica aerogel combined with the honeycomb geometry effectively inhibits heat transfer between battery cells, providing critical exhaust time and minimizing the possibility of full-module fire. This design supports scalability and offers options such as single-panel configurations, thereby reducing material usage and simplifying production.
At the individual battery level, the insulation layer applied to the top and sides of the battery cell uses a material with a thermal conductivity of less than 0.2 W/m·K to target the most vulnerable areas to heat and flame penetration. By blocking the heat flow from overheated batteries, this insulation layer limits the risk of heat propagation to adjacent batteries without significantly affecting energy density or mechanical structure.

6. Aerogel-Based Insulation System for Battery Modules or Battery Packs
Battery pack thermal management requires a thermal insulation system that provides thermal protection under dynamic conditions while maintaining mechanical integrity. The aerogel-based insulation system has excellent thermal performance, but it must be firmly integrated to function effectively.
The integration of aerogel battens employs mechanical locking technology, using hangers and hooks to securely fix the insulation material to the side plates of the battery pack. This ensures uniform contact between the insulation material and the battery surface, eliminating air gaps that affect performance. Ultimately, a solid insulation layer is formed, which is not prone to detachment under vibration and enhances insulation and shock absorption.

7. Anisotropic or Directional Heat Transfer Aerogel Insulation Materials
The thermal management of high-energy density battery packs requires complex heat flow control methods. Anisotropic insulation materials have the ability to transfer heat directionally, significantly improving the safety and performance of batteries. The laminated insulation material composed of two anisotropic outer layers and a compressible inner layer represents a significant advancement in this field. The compressible inner core uses aerogel and other low thermal conductivity materials, providing insulation while also absorbing mechanical stress generated by battery expansion during charging and discharging cycles. This directional heat transfer mechanism does not require expensive graphene-based composite materials, but can enhance insulation performance and safety, providing a lightweight, scalable, and cost-effective solution for the integration of square or pouch batteries. The multi-layer aerogel flame-retardant sheet materials for battery packs of new energy vehicles adopt a unique directional thermal management method. This structure includes two aerogel-based insulation layers and an interlaced heat-conducting layer made of copper foil and/or graphene composite materials. The insulation layer provides lateral thermal isolation between battery cells, while the heat-conducting layer bends downward to carry heat away from the core of the battery module, preventing heat from spreading across battery cells. This controlled vertical heat dissipation design complies with national flame retardant standards and enhances mechanical buffering and structural flexibility. This design replaces traditional plastic separators and aerogel-based insulation materials with a lightweight, efficient insulation material, achieving a balance between fire resistance and thermal management.