What Materials Are Used in EV Battery Thermal Interface?

The thermal interface materials in EV batteries work hard. They must conduct heat efficiently while insulating electrically. If they fail, batteries overheat or short-circuit.

Common EV battery thermal interface materials include thermal pads, gap fillers, phase change materials, thermal tapes, and adhesives. These materials transfer heat from battery cells to cooling systems while providing electrical insulation and mechanical protection.

Battery thermal management is critical. Poor heat dissipation reduces battery life and performance. In worst cases, it causes thermal runaway. The right thermal interface material makes all the difference.

Why Do EV Batteries Need Thermal Interface Materials?

EV batteries generate heat during charging and discharging. Without proper management, this heat builds up dangerously.

Thermal interface materials maintain optimal battery temperatures by filling gaps between components. They conduct heat away from cells while preventing electrical shorts and mechanical damage from vibration.

Let's examine the key functions:

Three Main Roles of Thermal Interface Materials

The materials must perform under tough conditions. They face temperature swings from -40°C to 120°C. They endure constant vibration during vehicle operation. Their performance degrades over years of use.

What Are the Most Common Thermal Interface Materials?

Manufacturers use different materials based on cost, performance needs and application methods.

The five primary thermal interface materials for EV batteries are silicone thermal pads, gap filler materials, phase change materials, thermal conductive tapes, and thermally conductive adhesives. Each has distinct advantages for different battery designs.

Let's examine each type:

1. Silicone Thermal Pads

Silicone pads are pre-formed sheets. They come in standard thicknesses from 0.5mm to 5mm. Workers place them between battery cells and cooling plates.

Benefits:

• Easy to install (pre-cut shapes available)

• Good balance of thermal conductivity and electrical insulation

• Compressible to fill small gaps

Typical specifications:

• Thermal conductivity: 1-5 W/mK

• Operating temperature: -50°C to 200°C

• Compression set: <20% after long use

2. Gap Filler Materials

These are paste-like compounds. Technicians dispense them between components then compress during assembly.

Advantages:

• Fills larger, uneven gaps (up to 10mm)

• Higher thermal conductivity than pads (up to 8 W/mK)

• Bonds components together slightly

Common formulations use silicone with ceramic or metal particle fillers. The fillers boost thermal performance.

3. Phase Change Materials (PCMs)

PCMs melt slightly at operating temperature. The phase change improves contact with surfaces.

Key features:

• Low pressure needed for good contact

• Self-healing properties

• Maintain performance through thermal cycles

They typically use paraffin or polymer bases with thermal additives. The melting point matches the battery's normal operating range.

4. Thermal Conductive Tapes

These adhesive tapes combine thermal transfer with bonding.

Main uses:

• Attaching small components like sensors

• Temporary fixing during assembly

• Low to medium thermal needs

Acrylic or silicone adhesives carry ceramic or metal particles. The bond strength varies by product.

5. Thermally Conductive Adhesives

These materials bond and transfer heat simultaneously.

Applications:

• Permanent structural bonds

• High reliability connections

• Where mechanical fasteners can't be used

They cure to form rigid or flexible bonds. Thermal performance depends on the filler content.

How Does Fuqiang Group Support EV Battery Manufacturers?

Fuqiang Group specializes in producing high-performance thermal interface materials for EV batteries. With 19 years of experience, we provide customized solutions that combine superior thermal management with automotive-grade reliability.

Five Factory Advantages for Customers:

1. Material Customization: We engineer custom formulations of silicone pads, gap fillers and other materials to match exact thermal and mechanical requirements.

2. Precision Manufacturing: Our ±0.1mm tolerance die-cutting ensures perfect fit for battery module components every time.

3. Mass Production Capacity: 12 automated production lines support monthly deliveries of over 1 million pieces without compromising quality.

4. Full Compliance: All materials meet IATF 16949 standards and pass UL94 V-0 flame tests critical for battery safety.

5. Global Supply Network: Multiple China factories plus international bases enable fast responses to customer needs worldwide.

How Do Manufacturers Choose the Right Material?

Material selection involves balancing multiple factors. Cost competes with performance and manufacturability.

Engineers evaluate thermal needs, assembly process, reliability requirements and cost constraints. The best choice depends on battery design, operating conditions and production volume.

Key decision factors include:

Thermal Performance Parameters

Manufacturing Considerations

• Assembly method (manual vs automated)

• Cure time (for adhesives and gap fillers)

• Shelf life and storage conditions

• Cleanliness requirements

Reliability Testing

Materials must pass:

• Thermal cycling tests (-40°C to 85°C, 1000+ cycles)

• Vibration resistance (automotive grade)

• Long-term aging (10+ year lifespan)

• Flame retardancy (UL94 V-0 typically)

Cost Factors

• Material cost per battery pack

• Application equipment investment

• Scrap and rework rates

• Assembly time impact

Large manufacturers often develop custom formulations. These match their specific battery architecture and production processes.

Conclusion

EV battery thermal interface materials quietly do vital work. They keep batteries cool, safe and reliable through years of demanding use. At Fuqiang Group, we combine material expertise with precision manufacturing to deliver thermal solutions that enhance battery performance while meeting rigorous automotive standards. Our vertically integrated production ensures consistent quality from material formulation to final die-cut components - helping EV manufacturers achieve better thermal management with fewer compromises.