Views: 0 Author: Site Editor Publish Time: 2025-06-17 Origin: Site
Flame retardant (FR) fabrics play a critical role in enhancing safety in electric vehicle (EV) battery systems by mitigating fire risks associated with thermal runaway.
As the Chinese biggest fiber glass fabric supplier for mica tape industry, Changzhou Xingao Insulation Materials Co.,Ltd. is professional on FR FABRIC & EV battery production. www.czxingao.com. www.rightcomposite.com. We are experts in handling very thin fiberglass fabrics (＜36 um).
Here’s how they are strategically integrated:
1. Primary Functions:
Containment: Isolating failing cells/modules to prevent cascading thermal runaway.
Heat Insulation: Blocking radiant/convective heat from spreading.
Fire Suppression: Smothering flames or delaying ignition.
Toxic Fume Management: Filtering hazardous gases during failure.
2. Key Applications in EV Batteries:
A. Cell/Pack Wrapping & Sleeving
FR Sleeves: High-temperature fabrics (e.g., silica, aramid, fiberglass) wrap individual cells/modules to contain flames and ejecta.
Mica-Laminated Fabrics: Used as heat shields around high-risk zones, leveraging mica’s >1000°C stability.
B. Intercell/Intermodule Barriers
Flexible FR Mats: Placed between cells/modules to:
Absorb thermal energy.
Prevent direct flame contact.
Block hot gases.
Materials: Needle-punched ceramic fiber fabrics or basalt FR fabrics with high compression resistance.
C. Battery Enclosure Liners
Multi-Layer Blankets: FR fabrics line the battery tray/cover as:
Thermal Barriers: Silica or vermiculite-coated fabrics reflect heat.
Fireproof Seals: Expandable graphite-infused fabrics seal gaps during fire.
D. Venting Systems
Flame-Arresting Vents: FR mesh fabrics (e.g., stainless steel + ceramic fibers) cover pressure relief valves:
Allow gas escape.
Trap flames/particles.
E. High-Voltage Cable Protection
FR Conduits: Braided aramid or fiberglass sleeves protect wiring from arc faults or external fires.
3. Material Requirements:
Temperature Resistance: Must withstand >800°C (thermal runaway peaks at 600–1000°C).
Low Thermal Conductivity: Delay heat transfer to adjacent cells.
Chemical Resistance: Withstand exposure to electrolytes/solvents.
Lightweight & Flexible: Avoid adding excess weight or restricting pack design.
Compression Stability: Maintain integrity under mechanical stress.
4. Common FR Fabrics Used:
Material | Key Properties | Use Case |
Silica Fabric | >1000°C stability, low thermal conductivity | Fire blankets, enclosure liners |
Aramid (e.g., Nomex®) | Self-extinguishing, high strength | Cable sleeves, intercell barriers |
Basalt Fiber | Inorganic, UV/chemical-resistant | Pack wraps, thermal mats |
Fiberglass + FR Coating | Cost-effective, dielectric | Lower-risk insulation |
Ceramic Fiber | Ultra-high temperature (>1260°C) | Critical hot-zone protection |
As the Chinese biggest fiber glass fabric supplier for mica tape industry, Changzhou Xingao Insulation Materials Co.,Ltd. is professional on FR FABRIC & EV battery production. www.czxingao.com. www.rightcomposite.com. We are experts in handling very thin fiberglass fabrics (＜36 um).
Here's a technical breakdown of thin mica composites with fiberglass substrates for EV battery protection – a cutting-edge solution balancing extreme thermal protection with space/weight constraints:
1. Structure & Composition
Layer | Function | Thickness Range |
Fiberglass Substrate | Mechanical backbone (flexibility + strength) | 0.05–0.15 mm |
Mica Core | Primary thermal/electric barrier | 0.02–0.08 mm |
Reinforcing Scrim | Prevents delamination (glass/aramid mesh) | 0.01–0.03 mm |
Functional Coating | Enhances ablation/chemical resistance | 0.005–0.02 mm |
Total Thickness | 0.08–0.25 mm |
2. Critical Performance Advantages
Property | Performance Data | EV Battery Benefit |
Thermal Stability | Withstands 1200°C for 2+ hours | Contains cell-to-cell thermal runaway propagation |
Thermal Conductivity | 0.05–0.08 W/m·K (in-plane) | Slows heat transfer 5x faster than ceramic fiber |
Dielectric Strength | >30 kV/mm @ 500°C | Prevents arcing in 800V+ architectures |
Areal Density | 80–200 g/m² (vs. 300–600 g/m² for pure mica) | Reduces pack weight penalty by 40% |
Gas Impermeability | 0% open porosity | Blocks explosive vent gases from igniting adjacent cells |
3. Key Applications in EV Batteries
A. Intercell/Intermodule Barriers
0.1mm composite sheets between prismatic/pouch cells
Function: Absorbs 1.2–1.8 kJ/g during thermal runaway
B. Firewall Blankets
Laminated wraps around battery modules
Structure: Fiberglass (outer) + Mica (core) + Silica coating (inner)
Survives: Direct flame impingement >15 mins (UN ECE R100)
C. Busbar/Cable Armor
Adhesive-backed tapes (0.08mm) on high-voltage connections
Withstands: 2000°C arc flashes (UL 746C)
D. Top Cover Insulation
Perforated composites under pack covers
Allows gas venting while trapping flames
4. Manufacturing Innovations
Precision Lamination: Roll-to-roll nano-adhesive bonding (<5μm glue lines)
Mica Paper Tech: Exfoliated phlogopite flakes → 98% crystallinity for uniform insulation
Edge Sealing: Laser-fused silica borders prevent fraying
Hybrid Coatings:
Ceramic nanoparticles (Al₂O₃) for thermal buffering
Intumescent additives expand at 180°C to seal gaps
5. Performance Comparison
Parameter | Mica/FG Composite | Pure Mica Tape | Silica Fabric |
Min. Thickness | 0.08 mm | 0.25 mm | 0.15 mm |
Flex Cycles | 50,000+ (ASTM D2176) | <500 | 20,000 |
Cost (per m²) | $18–35 | $45–90 | $25–50 |
Thermal Runaway Containment | 8–12 cells | 12–15 cells | 5–8 cells |
6. Real-World Implementations
Tesla Structural Packs:
0.15mm mica/fiberglass between 4680 cells → survives 3+ consecutive runaway events
BYD Blade Battery:
Mica-composite busbar wraps in LFP packs (reduced arc faults by 92%)
GM Ultium:
0.1mm laser-cut barriers for pouch cell isolation
7. Limitations & Solutions
Challenge | Engineering Fix |
Vibration Fatigue | Aramid stitch reinforcement at stress points |
Moisture Absorption | Hydrophobic fluoropolymer coatings (0.3% max. uptake) |
Adhesion Failure | Plasma-treated fiberglass + silane primers |
Edge Delamination | Micro-crimped borders with ceramic adhesive |
8. Future Directions
Self-Monitoring Composites:
Embedded graphene sensors mapping thermal gradients
Phase-Change Integration:
Paraffin microcapsules in mica layers absorb 250 J/g during runaway
Sustainable Versions:
Recycled fiberglass + bio-silicone binders (45% lower CO₂)
Conclusion
Thin mica-fiberglass composites solve EV battery protection’s core dilemma: stopping fire propagation in <0.2mm spaces while surviving hellish thermal/electrical stresses. By leveraging:
✅ Mica’s imperviousness to heat/flame
✅ Fiberglass’s structural resilience
✅ Nano-coatings’ multifunctional enhancement
They outperform monolithic materials in containment efficiency, weight savings, and design flexibility. As energy densities push beyond 400 Wh/kg, this hybrid approach becomes essential for meeting UN R100, GB 38031, and IEC 62660-2 safety mandates.
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