BESS Thermal Runaway Protection Pad — Microporous Fire Barrier for Energy Storage Systems
 
DARQ BESS thermal runaway protection pads are ultra-thin microporous fire barriers engineered for Battery Energy Storage Systems (BESS) and grid-scale energy storage systems (ESS). Placed between cells, modules, or racks, these thermal barrier pads delay the propagation of a thermal runaway event — buying critical minutes for containment, venting, and suppression systems to respond. Rated to 1000°C, classified UL94 V0, and available from just 0.6 mm thickness, they are made to order in India for energy storage OEMs, system integrators, and EPC contractors.
 
Why BESS and ESS Systems Need a Dedicated Thermal Barrier
In a battery energy storage system, a single cell entering thermal runaway releases intense heat that can cascade to adjacent cells and modules — a chain reaction that can escalate to a full-system fire within minutes. In containerised and rack-mounted BESS installations, this cell-to-cell and module-to-module propagation is the primary risk that standards like UL 9540A and NFPA 855 are designed to address. A thin microporous thermal runaway barrier placed at these interfaces interrupts the heat transfer, slowing propagation and giving suppression and shutdown systems the time they need to prevent a localised failure from becoming catastrophic.
 
Technical Specifications
DARQ BESS thermal runaway pads use an opacified pyrogenic silica microporous core with filament reinforcement — proven passive fire protection technology adapted for lithium-ion battery safety.
Classification temperature: 1000°C
Fire rating: UL94 V0
Nominal density: 350 ±10% kg/m³
Cold compressive strength (10% deformation): ≥0.3 MPa
Thermal conductivity: ≤0.023 W/m·K at 200°C, ≤0.03 at 400°C, ≤0.04 at 800°C (ASTM C177)
Dielectric strength: ≥5 kV/mm
Insulation resistance: ≥6 GΩ
Thickness range: 0.6–8 mm (made to order)
Encapsulation: Mica / PET / Fibre Cloth
Tolerances: ±2 mm (length × width), ±0.2 mm (thickness)
 
Sealed-Edge Encapsulation for Clean BESS Integration
For energy storage applications, DARQ offers precision edge-sealed encapsulation — the microporous core is fully enclosed in a Mica, PET, or fibre-cloth covering with a clean, heat-sealed perimeter. This finish matters at BESS scale: it eliminates fibre shedding inside sealed battery enclosures, allows clean handling and accurate placement of large-format pads in racks and modules, supports the pad's ≥5 kV/mm dielectric isolation between modules, and holds tight dimensional tolerances for repeatable high-volume production. This sealed-edge finish was developed for and supplied to energy storage clients who need a thermal barrier that installs cleanly at rack and module scale without the fibre-release problems of open-edge insulation.
 
BESS and ESS Applications
Cell-to-cell barriers: Ultra-thin pads (from 0.6 mm) between prismatic or pouch cells to delay propagation while acting as a compression pad that absorbs cell swelling over the system's life. EV battery thermal runaway pads made with microporous insulation
Module-to-module barriers: Thicker sections between modules within a rack to contain a module-level failure and prevent escalation to neighbouring modules.
Rack and enclosure fire barriers: Large-format pads for compartment separation within containerised BESS, supporting compliance goals under UL 9540A and NFPA 855.
Compression pads: Because the material maintains fire performance even when compressed, it doubles as a mechanical compression layer, maintaining correct stack pressure across charge and discharge cycles and cell ageing.
 
Why Choose DARQ for BESS Thermal Protection
DARQ is an ISO 9001:2015 certified advanced thermal insulation manufacturer in India, supplying 1000°C-rated microporous thermal runaway barriers with ultra-thin profiles from 0.6 mm that maximise energy density. All pads are made to order in custom sizes, thicknesses, and encapsulation, with PAN-India supply and export to GCC, UAE, and Southeast Asia, backed by direct engineering support to help you specify the right barrier for your energy storage system.