# Liquid Silicone Automotive High Voltage Waterproof Parts for New Energy Vehicles
(98 Hardness Grade)
Product Overview
Liquid Silicone Rubber (LSR) high-voltage waterproof parts for new energy vehicles (NEVs) are mission-critical sealing and insulating components engineered to protect high-voltage electrical systems from environmental intrusion, electrical breakdown, and mechanical failure. This 98 hardness grade formulation is purpose-built for the extreme demands of NEV high-voltage architectures, where reliable sealing of 400V/800V powertrain circuits, battery management systems, and charging interfaces is non-negotiable for passenger safety and vehicle operational stability.
Unlike conventional rubber sealing components, these LSR parts are injection-molded under cleanroom conditions to deliver micron-level dimensional precision, zero porosity, and consistent performance across a -60°C to 220°C operating temperature range. Core functional features include IP68/IP6K9K ingress protection rating, 15kV/mm dielectric strength, and resistance to automotive fluids, UV radiation, and long-term thermal cycling. The 98 Shore A hardness strikes a unique balance between rigid structural support for high-voltage connector retention and sufficient compression set resistance to maintain a hermetic seal over 15+ years of vehicle service life, eliminating the risk of water intrusion, current leakage, or arcing that could lead to battery fires or powertrain shutdowns.
Technical Specifications
Material Properties
ParameterTest StandardValueNotes
Base Material-Medical/food-grade liquid silicone rubber (two-component, platinum-cured)Free of DOP, phthalates, heavy metals, and RoHS-restricted substances
HardnessASTM D224098 ± 2 Shore AUltra-high hardness grade for structural sealing applications
DensityASTM D7921.18 ± 0.03 g/cm³Low specific gravity reduces overall vehicle weight vs. fluororubber alternatives
Tensile StrengthASTM D412≥ 8.5 MPaResists tearing during assembly and long-term vibration stress
Elongation at BreakASTM D412≥ 120%Accommodates minor dimensional shifts from thermal expansion and connector mating tolerance
Compression SetASTM D395 Method B (22h @ 150°C, 25% compression)≤ 8%Maintains consistent sealing pressure over the full vehicle service life
Dielectric StrengthIEC 60243-1≥ 15 kV/mmPrevents electrical breakdown in 800V high-voltage NEV architectures
Volume ResistivityIEC 60093≥ 10¹⁶ Ω·cmEnsures stable electrical insulation in high-humidity environments
Flammability RatingUL 94V-0Self-extinguishing to minimize fire risk in the event of electrical failure
Physical Performance
ParameterTest ConditionValue
Operating Temperature RangeContinuous exposure-60°C to 220°C
Short-Term Temperature Resistance1-hour exposure260°C
Ingress Protection RatingIEC 60529IP68 (2m depth, 72h immersion, no leakage) / IP6K9K (high-pressure hot water jetting, 80°C, 100bar pressure, no water ingress)
Fluid Compatibility1000h immersion at 80°CNo swelling > 2% in engine coolant, gear oil, brake fluid, lithium-ion battery electrolyte; no degradation in 5% NaCl salt spray
Vibration ResistanceIEC 60068-2-6 (10-2000Hz, 10g acceleration, 100h)No cracking, seal leakage, or connector dislodgement
Thermal Cycling Resistance1000 cycles (-40°C to 125°C, 30min dwell per cycle)< 3% change in hardness, < 5% change in sealing compression force
UV ResistanceASTM G154 (1000h, 340nm UV, 0.89W/m² irradiance)No discoloration, cracking, or surface degradation
Process Parameters
Molding ParameterRecommended RangeNotes
A/B Component Mixing Ratio1:1Pre-mixed under vacuum to eliminate air bubbles
Injection Temperature15°C to 25°CCold runner system to prevent premature curing
Mold Temperature170°C to 190°CUniform heating across mold cavity to ensure consistent crosslinking
Curing Time30s to 90sAdjusted based on part wall thickness (1mm wall thickness requires ~30s cure)
Injection Pressure80bar to 120barLow shear injection to avoid material degradation
Post-Curing2h @ 200°COptional, for applications requiring maximum compression set resistance and low volatile organic compound (VOC) emissions
Dimensional ToleranceISO 3302-1 Class M1±0.02mm for features < 10mm, ±0.05mm for features 10-50mm, ±0.1mm for features > 50mm
Product Advantages
1. Industry-Leading High-Voltage Insulation and Safety Performance
The 98 hardness LSR formulation delivers 15kV/mm dielectric strength, exceeding the 10kV/mm minimum requirement for 800V NEV high-voltage systems, with a UL 94 V-0 flammability rating that prevents flame spread in the event of electrical arcing. Unlike EPDM or fluororubber alternatives, which can suffer dielectric breakdown after prolonged exposure to high temperatures and moisture, this LSR material maintains > 95% of its insulation performance after 1000h of 85°C/85% RH damp heat testing, eliminating the risk of current leakage that could cause electric shock or battery thermal runaway.
2. Exceptional Long-Term Sealing Reliability
With a compression set of ≤ 8% at 150°C, these parts maintain consistent sealing pressure over 15+ years of service, even after repeated thermal cycling and mechanical vibration. The 98 Shore A hardness provides sufficient rigidity to resist extrusion under high mating forces, while 120% elongation at break accommodates dimensional shifts from thermal expansion of metal connector housings. The IP68/IP6K9K ingress protection rating ensures no water or dust intrusion even during deep water fording, high-pressure car washes, or prolonged exposure to heavy rain and road spray.
3. Superior Material Stability in Automotive Environments
This LSR formulation is inherently resistant to all common automotive fluids, including battery electrolyte, engine coolant, gear oil, and road salt, with < 2% volume swelling after 1000h of immersion. Unlike rubber materials that degrade and crack after 3-5 years of UV exposure and thermal aging, the LSR parts show no surface degradation or performance loss after 1000h of accelerated UV testing, making them suitable for under-hood and external charging port applications.
4. Precision Manufacturing for High-Volume NEV Production
Injection-molded in Class 100,000 cleanrooms with automated material feeding and quality inspection systems, these parts deliver consistent micron-level dimensional accuracy, with a < 0.1% defect rate in mass production. The fast curing cycle of LSR enables high-volume production output of up to 100,000 parts per day per mold, supporting the rapid scaling of NEV manufacturing lines. The material is also free of RoHS and REACH restricted substances, with low VOC emissions that meet automotive interior air quality standards.
Applications
These 98 hardness LSR high-voltage waterproof parts are optimized for the following NEV high-voltage system applications:
- Battery Pack Seals: High-voltage feedthrough grommets, module-to-module connector seals, and battery enclosure peripheral gaskets, preventing electrolyte leakage and water intrusion into 400V/800V battery packs.
- Power Distribution Unit (PDU) Components: Insulating spacers, busbar seals, and connector interface gaskets for high-voltage power distribution units, ensuring stable insulation between live components.
- E-Motor and Inverter Seals: High-voltage connector seals for traction motors and motor controllers, resisting continuous high operating temperatures up to 180°C and vibration from powertrain operation.
- Charging System Components: DC fast charging port sealing rings, charging cable connector grommets, and on-board charger (OBC) interface seals, providing IP6K9K protection against high-pressure car washes and outdoor environmental exposure.
- **High-Voltage Wiring Harness Components: Grommets, seals, and strain reliefs for high-voltage cables running between the battery, PDU, motor, and charging port, sealing against body panel cutouts and preventing water ingress into the passenger compartment and under-hood systems.
Selection Guide
Hardness Selection
- 98 Shore A (this product): Recommended for structural sealing applications requiring high connector retention force, resistance to extrusion under high pressure, and stable performance in high-vibration environments, such as battery pack feedthroughs, charging port seals, and heavy-duty high-voltage connector gaskets.
- For applications requiring greater flexibility (e.g., wiring harness grommets with complex bending requirements), we offer 50-70 Shore A LSR formulations. For medium-stiffness sealing applications, 70-90 Shore A grades are available.
Size Specifications
Standard parts are available for all common NEV high-voltage connector sizes, including:
- HV connector seals for 16mm², 35mm², 50mm², 70mm², and 95mm² cable diameters
- Charging port seals compatible with GB/T, CCS1, CCS2, and CHAdeMO charging standards
- Battery pack feedthrough grommets for 2-12 core high-voltage connectors
Custom tooling is available for non-standard sizes or application-specific geometries, with a 2-4 week lead time for mold development and sample production.
Material Grade
- Standard Automotive Grade: Meets RoHS, REACH, and GB/T 30512 automotive material requirements, suitable for most under-hood and external applications.
- Low VOC Grade: Post-cured to reduce volatile organic compound emissions, meeting VDA 278 and ISO 12219-1 interior air quality standards for high-voltage components installed in the passenger compartment.
- Flame-Retardant Enhanced Grade: Formulated with additional flame retardants to meet UL 94 V-0 rating at 0.8mm thickness, recommended for high-power density battery pack applications.
Quality Assurance
All LSR high-voltage waterproof parts are manufactured under IATF 16949 automotive quality management system standards, with end-to-end quality control processes:
- Incoming Material Inspection: Every batch of LSR raw material is tested for hardness, tensile strength, and dielectric strength before entering production, with material traceability records maintained for 15 years per automotive requirements.
- In-Process Quality Control: Automated vision inspection systems check 100% of parts for dimensional accuracy, surface defects, and flash, with real-time SPC monitoring of molding parameters to ensure consistent quality.
- Finished Product Testing: Each production lot undergoes type testing, including compression set testing, ingress protection testing, dielectric strength testing, and thermal cycling testing, with test reports provided with every shipment.
- Certifications: All parts are certified to IEC 60664-1 insulation coordination standards for low-voltage electrical systems, RoHS 2.0, REACH SVHC, and UL 94 V-0 flammability rating. Third-party test reports from CNAS/A2LA accredited laboratories are available upon request.
- Warranty: We offer a 5-year warranty on all parts against material defects and performance degradation under normal use conditions, with full technical support for material selection, design optimization, and assembly process guidance.
