Case Study: Custom Sealing Solution for Electric Vehicle Battery Pack
As electric vehicles continue to dominate the automotive market in 2025, battery pack sealing has become critical for safety, performance, and longevity. This case study demonstrates how we helped a major EV manufacturer solve a critical battery sealing challenge.
Client Background
| Industry | Electric Vehicle Manufacturing |
| Location | Southeast Asia |
| Product | Premium Electric SUV (80 kWh battery pack) |
| Production Volume | 50,000+ units annually |
| Challenge Area | Battery pack housing sealing |
The Challenge
Problems Identified:
1. Water Ingress Issues
- Battery packs failed IP67 waterproof testing
- Moisture detected inside battery housing after road testing
- Risk of short circuits and battery degradation
2. Thermal Management Problems
- Original gasket material degraded at high temperatures (80-90°C)
- Compression set exceeded 30% after 1,000 hours at 85°C
- Sealing effectiveness reduced during fast charging cycles
3. Installation Difficulties
- Existing gasket design required 45+ minutes to install
- Multiple pieces increased assembly complexity
- High rejection rate due to improper installation (8-12%)
4. Cost Pressures
- Previous supplier's gasket cost was too high
- Needed to reduce per-vehicle sealing cost by 20-30%
Our Solution
Phase 1: Technical Analysis (Week 1-2)
What we did:
- Reviewed battery pack design and sealing requirements
- Analyzed failure modes from customer's testing data
- Studied operating conditions: temperature range (-40°C to +95°C), IP67 requirement, coolant compatibility
- Examined installation process and production line constraints
Phase 2: Custom Design (Week 3-4)
Design improvements:
✅ Material Selection: Premium EPDM (Peroxide-Cured)
- Temperature range: -40°C to +150°C
- Excellent resistance to coolant (water-glycol mixture)
- Low compression set: <15% after 1,000 hrs @ 100°C
- Superior weather and ozone resistance for long-term durability
✅ Integrated Gasket Design
- Combined 3 separate gaskets into single one-piece design
- Molded corner sections eliminate leak paths
- Built-in positioning tabs for foolproof installation
- Reduced total gasket parts from 5 pieces to 1 piece
✅ Enhanced Sealing Features
- Double sealing lip design for IP67 protection
- Optimized compression ratio (22% vs. previous 18%)
- Corner reinforcement to prevent extrusion under pressure
✅ Installation Improvement
- Pressure-sensitive adhesive (PSA) backing on one side
- Color-coded alignment markers
- Installation guide and training provided
Phase 3: Prototyping & Testing (Week 5-8)
| Test | Requirement | Result |
|---|---|---|
| IP67 Water Ingress | 1m depth, 30 minutes | ✅ Pass (no water detected) |
| Thermal Cycling | -40°C to +95°C, 500 cycles | ✅ Pass (no leaks) |
| Compression Set | <20% @ 100°C, 1000 hrs | ✅ 14.5% (exceeds requirement) |
| Coolant Compatibility | 168 hrs immersion @ 100°C | ✅ Volume change <5% |
| Vibration Test | 10-2000 Hz, 8 hours | ✅ Pass (seal maintained) |
| Installation Time | Target: <20 minutes | ✅ 12 minutes average |
Phase 4: Production & Delivery (Week 9+)
- Compression molding process for consistent quality
- 100% dimensional inspection using CMM
- Clean room packaging to prevent contamination
- Just-in-time delivery to customer's assembly line
Results & Benefits
✅ Performance Improvements
|
🔒 Sealing Performance
|
🌡️ Thermal Management
|
✅ Operational Benefits
|
⏱️ Production Efficiency
|
💰 Cost Savings
|
Customer Testimonial
"The custom EPDM gasket solution from Best Seal completely solved our battery pack sealing challenges. The one-piece design not only improved sealing performance but also dramatically reduced our assembly time and costs. Their technical team's expertise in EV applications was impressive, and the fast turnaround on prototyping helped us stay on schedule for production launch."
- Engineering Manager, EV Battery Division
Major Automotive Manufacturer, Southeast Asia
Technical Specifications
| Parameter | Specification |
|---|---|
| Material | EPDM (Peroxide-Cured), 70 Shore A |
| Dimensions | Custom frame gasket: 1850mm × 1200mm × 8mm thickness |
| Temperature Range | -40°C to +150°C continuous operation |
| Compression Set | 14.5% (22 hrs @ 100°C per ASTM D395) |
| Sealing Rating | IP67 (1m water depth, 30 minutes) |
| Manufacturing Method | Compression molding with vulcanized corners |
| Features | Double sealing lip, PSA backing, positioning tabs |
| Certifications | RoHS, REACH compliant |
| Service Life | 8+ years under normal operating conditions |
Why This Solution Worked
1. Deep Industry Knowledge
Our team understands the unique challenges of EV battery pack sealing: thermal management, coolant compatibility, and IP67 requirements.
2. Advanced Material Selection
Peroxide-cured EPDM was specifically chosen for its superior heat aging resistance and low compression set-critical for battery pack applications.
3. Design for Manufacturing
The integrated one-piece design eliminated assembly complexity while improving sealing performance-a win-win solution.
4. Comprehensive Testing
Rigorous validation testing ensured the gasket would perform reliably under real-world operating conditions.
5. Partnership Approach
Close collaboration with the customer's engineering team throughout development ensured the solution met all requirements.
Learn More
Are you facing sealing challenges in your electric vehicle or battery system application? Our engineering team specializes in custom sealing solutions for the EV industry.
We can help with:
- Battery pack housing seals (IP67/IP68)
- Thermal management system gaskets
- Power electronics enclosure seals
- Motor and drivetrain sealing solutions
- Charging port and connector seals
Related Products:
Custom Rubber Gaskets👉 | O-Rings for EV Applications👉 | Molded Rubber Components👉
Contact US
Ready to discuss your EV sealing requirements?
Xiamen Best Seal Imp and Exp Co.,Ltd
Tel: +86-592-5782315
Mob: +8618950159396
Email: yunying2@bestsealhk.com
Add: Unit 522-525, Gaodian Road 6#, Huli District, Xiamen, China
Keywords: EV Battery Sealing, Electric Vehicle Gaskets, Battery Pack Gasket, IP67 Sealing, EPDM Gasket, Automotive Sealing Solution, Custom EV Gaskets
Date: December 2025
