Liquid Silicone Waterproof Ring for New Energy Vehicle Batteries

# Liquid Silicone Waterproof Ring for New Energy Vehicle Batteries

Product Overview

The Liquid Silicone (LSR) Waterproof Ring for New Energy Vehicle (NEV) Batteries is a high-performance sealing component engineered to address the strict environmental protection requirements of power battery systems, the core component of electric and hybrid electric vehicles. Manufactured via precision injection molding of medical/food-grade liquid silicone rubber, this product delivers long-lasting, reliable sealing against water, dust, coolant, and atmospheric contaminants, directly supporting the IP67/IP6K9K ingress protection ratings mandated for NEV power packs.

Unlike traditional EPDM or nitrile rubber sealing rings, this LSR waterproof ring maintains dimensional stability and sealing performance across the extreme temperature, vibration, and chemical exposure conditions common in NEV operation. It is designed for seamless integration into prismatic, cylindrical, and pouch battery pack housings, battery management system (BMS) enclosures, high-voltage connector interfaces, and cooling system ports. Core selling points include a 15+ year service life matching the expected lifespan of NEV power batteries, zero permanent deformation under long-term compression, and compatibility with automated high-volume assembly lines.

Technical Specifications

Material Properties

All LSR waterproof rings are formulated with high-purity platinum-cured liquid silicone rubber, free of plasticizers, halogenated flame retardants, and heavy metals to meet global RoHS 2.0 and REACH compliance requirements.

Physical Performance

The product’s physical properties are optimized for the dynamic operating conditions of NEV battery packs:

Process Parameters

All rings are produced with precision injection molding to ensure ±0.02mm dimensional tolerance for high-volume assembly compatibility:

Product Advantages

1. Extreme Temperature Stability for Harsh Operating Environments

Unlike EPDM seals that become brittle below -40°C or lose elasticity above 120°C, this LSR waterproof ring retains full sealing performance across -60°C to 220°C, eliminating failure risks during cold-start operations in high-latitude regions or prolonged high-load battery operation during fast charging and high-speed driving. Its low compression set also prevents leakage caused by thermal expansion and contraction cycles during daily charge/discharge cycles.

1. 15+ Year Service Life Matching Battery Lifespan

The platinum-cured LSR formulation offers exceptional resistance to hydrolysis, UV radiation, road salt, battery coolant, and trace electrolyte exposure, with accelerated aging tests confirming less than 10% hardness change and less than 3% dimensional drift after 15 years of simulated NEV operation. This eliminates the need for mid-life seal replacement, reducing total cost of ownership for NEV manufacturers and end users.

1. High Electrical Insulation for Battery System Safety

With a dielectric strength of ≥20 kV/mm, the waterproof ring provides an additional layer of insulation between battery pack housing components and high-voltage internal circuits, reducing the risk of short circuits caused by coolant leakage or water ingress. Its non-conductive properties also minimize electromagnetic interference (EMI) with BMS and high-voltage connector signals, supporting stable battery system operation.

1. Automated Assembly Compatibility

The precision ±0.02mm dimensional tolerance and low surface roughness ensure consistent fit in automated pick-and-place assembly lines, with a 99.98% assembly pass rate in high-volume production environments. The LSR material is also compatible with common adhesive and ultrasonic welding assembly processes, eliminating bonding failure issues common with low-quality silicone seals.

Applications

This LSR waterproof ring is designed for all high-sealing-demand components in NEV power battery systems:

• Battery Pack Housing Seals: Installed between the upper and lower housings of prismatic, cylindrical, and pouch battery packs to meet IP67 ingress protection (1m water immersion for 30 minutes) and IP6K9K high-pressure steam cleaning resistance, preventing water and dust ingress during wading and vehicle washing.
• High-Voltage Connector Seals: Used at the interface between battery pack output connectors and vehicle high-voltage wiring harnesses, sealing against moisture and dust to prevent arcing and short circuit risks.
• **BMS Enclosure Seals: Seals the housing of the battery management system, protecting sensitive electronic components from condensation, road salt, and coolant exposure to ensure accurate battery state of charge (SOC) and state of health (SOH) monitoring.
• Cooling System Port Seals: Installed at the inlet and outlet of liquid cooling plates, resisting long-term immersion in ethylene glycol-based battery coolants to prevent leakage that could cause thermal runaway.
• Module End Plate Seals: Used between individual battery modules and pack housing frames to absorb vibration and isolate modules from external contaminants, suitable for both cell-to-pack (CTP) and cell-to-chassis (CTC) battery architectures.

Selection Guide

Hardness Selection

• 30–40 Shore A: Recommended for irregular sealing surfaces, low compression force assembly requirements, and applications requiring high vibration absorption, such as pouch battery module seals and BMS enclosure seals. The lower hardness provides superior conformability to uneven surfaces with minimal assembly stress.
• 45–55 Shore A: The standard grade for most battery pack housing and cooling port seal applications, balancing sealing performance, compression resistance, and assembly ease. It is suitable for 90% of mainstream NEV battery pack designs.
• 60–70 Shore A: Recommended for high-pressure sealing applications (≥5 bar) and applications requiring high dimensional stability, such as high-voltage connector seals and cooling system ports for 800V fast-charging battery packs.

Size Specifications

Standard sizes are available for common battery pack configurations, with custom molding available for non-standard designs:

• For 100kWh prismatic battery pack housings: Standard outer diameter 1200mm × 800mm, cross-section diameter 2.0mm/3.0mm
• For cylindrical 4680 battery pack module seals: Standard outer diameter 180mm, cross-section diameter 1.5mm
• For high-voltage DC connector seals: Standard inner diameter 10mm/16mm/24mm, cross-section diameter 1.0mm/1.2mm

Custom sizes are available with a 7–10 day lead time for prototype samples, and 15–20 days for mass production tooling.

Material Grade

• Standard Automotive Grade: Meets RoHS 2.0 and REACH compliance, suitable for most mass-produced passenger NEV applications.
• Low-VOC Grade: Post-cured at 200°C for 2h to reduce volatile organic compound (VOC) emissions to ≤10μg/g, recommended for luxury NEVs and cabin-adjacent battery pack designs to meet interior air quality standards.
• High-Flame-Retardant Grade: Formulated with non-halogenated flame retardants to achieve UL94 V-0 rating at 0.8mm thickness, required for commercial electric vehicles and energy storage battery systems with stricter fire safety requirements.

Quality Assurance

All LSR waterproof rings are manufactured in IATF 16949 certified production facilities, with a multi-stage quality control process to ensure zero defect delivery:

1. Incoming Material Inspection: Each batch of LSR raw material is tested for molecular weight, curing performance, and impurity content before production, with traceability codes for all raw material batches.
2. In-Process Quality Control: 100% dimensional inspection via high-precision vision systems for every production batch, with random sampling for compression set, tensile strength, and sealing performance testing every 2 hours during production.
3. Final Performance Validation: Each batch undergoes simulated environmental testing, including 1000h temperature cycling (-40°C to 150°C), IP67 ingress testing, and coolant immersion testing, before shipment.
4. Certifications: All products are certified to IATF 16949 automotive quality standards, RoHS 2.0, REACH (SVHC 210 items), UL94 V-0, and CE, with full test reports provided with every shipment.
5. Warranty: We offer a 5-year quality warranty for all standard products, and a 10-year warranty for products qualified via customer-specific durability testing, covering all manufacturing defects and performance degradation outside of specified parameters.