Solving Thermal Management Through Material Selection

With the rise of e-mobility and electrification across manufacturing industries, successful thermal management is more critical than ever.

Thermal management is regulating heat within electrified systems so that devices and components operate without exceeding temperature limits. This helps to reduce system failure and operational inefficiency.

While thermal management presents many challenges, smart material selection can often solve them. Saunders, a division of R.S. Hughes and a leading provider of conversion services, commonly uses this process. It involves selecting flexible, non-metallic materials designed to mitigate and dissipate heat for specific devices or components.

Here, we will review the challenges of achieving effective thermal management and discuss how material selection can provide solutions.

Challenges in Thermal Management

There are five key challenges in thermal management:

1. Overheating: Risks to product performance and safety.
2. Performance Degradation: How improper thermal regulation impacts longevity and efficiency.
3. Uneven Temperature Distribution: Maintaining consistent temperature across components is challenging.
4. Cold Weather Performance: Impact of low temperatures on energy efficiency.
5. Thermal Runaway: Addressing hazards related to uncontrolled temperature increases.

Solutions through Flexible, Non-Metallic Materials

Manufacturers can solve unique thermal demands by utilizing flexible, non-metallic materials to improve product longevity and safety. Here are seven common solutions found through material selection:

1. Advanced Cooling Systems: Use of liquid cooling or advanced air-cooling systems to maintain optimal battery temperatures.
2. Thermal Insulation: Incorporating materials that provide better thermal insulation to protect cells from external temperature variations.
3. Battery Management Systems (BMS): Sophisticated BMS can monitor and regulate temperatures, ensuring even heat distribution across cells.
4. Phase Change Materials (PCMs): These materials absorb and release thermal energy, helping to stabilize battery temperatures.
5. Optimized Battery Design: Designing batteries with improved thermal pathways to enhance heat dissipation.
6. Preconditioning: Preheating or precooling the battery before use, especially in extreme weather conditions.
7. Use of Heat Pumps: Leveraging heat pumps to manage battery temperature more efficiently, especially in cold climates.

Types of Materials for Thermal Management

There are four materials commonly used for thermal management solutions, each with its own advantages and properties:

1. Thermal Interface Materials (TIMs):

• Silicone-Based Pads: Offer high thermal conductivity while remaining compressible and flexible.
• Graphite Sheets: Offer high thermal conductivity, flexibility, and thin profiles.
• Acrylic-Based Pads: Contains no intentionally added silicone which means no siloxane VOC or oil bleeding.

2. Polymer Composites:

• Thermally Conductive Polymers: Filled with conductive additives like ceramic particles to improve heat transfer.
• Polyimides: Offers high-temperature resistance and electrical insulation.

3. PCMs: 

• Encapsulated PCMs: Materials that can change from a solid to a liquid state at low temperatures, absorbing or releasing large amounts of energy in the process.

4. Silicone Foams:

• Utilizes flexibility for thermal insulation and vibration damping.

Factors to Consider for Material Selection

Effective thermal management relies heavily on selecting materials that align with the application’s specific demands. Key factors such as thermal conductivity, expansion properties, mechanical durability, and cost must be carefully evaluated to ensure optimal performance and reliability.

1. Thermal Conductivity

Thermal conductivity is a fundamental property to consider when it comes to thermal management. High thermal conductivity is crucial for applications involving heat dissipation, such as heat sinks, cooling systems, and TIMs.

For applications requiring low thermal conductivity and increased insulation, thermal barriers are commonly created using composites and polymers designed with thermal properties.

2. Thermal Expansion

The degree to which materials expand when heated is measured by the coefficient of thermal expansion (CTE). If materials don’t have compatible CTE values within a system, cracking, mechanical stress, or failing components can occur in high-temperature conditions.

3. Environmental and Mechanical Properties

It’s often essential to use materials that can withstand mechanical stress and environmental impacts such as corrosion, humidity, pressure changes, intense vibrations, and high temperatures. For example, certain metals may provide strong durability but may be susceptible to corrosive environments.

Polymers designed to withstand high temperatures are a common solution to harsh environments. Polyimides or thermoset composites offer a strong thermal stability and flexibility balance.

4. Cost and Availability

High-performance materials like advanced composites and graphene are commonly sought after for thermal management. However, they may not always be the most cost-effective for larger operations. A balance must be struck between budget parameters and efficiency.

To achieve this balance, manufacturers use hybrid materials designed with polymers and thermally conductive fillers, such as ceramic particles. These provide an effective and efficient solution, costing less than more advanced composites.

Applications for Across Industries

Thermal management is becoming an increasingly big concern across multiple industries. The electronic, automotive, and aerospace industries are utilizing flexible, non-metallic materials to create new, innovative solutions for enhanced performance and efficiency:

1. Electronics

Electronic equipment and devices are particularly susceptible to overheating, which can lead to degraded performance and component failure. Solutions like TIMs and printed circuit board (PCB) substrates can help dissipate heat and increase the longevity of electronic devices.

2. Automotive

With the rise of electric vehicles (EVs), the automotive industry is facing more thermal management challenges than ever. Combustion and electronic components within vehicles create excessive heat and require cooling and insulation to maintain operational safety and efficiency.

3. Aerospace

Within the aerospace industry, materials must be able to maintain structure while being exposed to extreme temperatures and harsh environments. Machinery and equipment like spacecraft and satellites create high thermal loads, requiring a high level of thermal management.

Thermal management is integral to each of these industries. By aligning materials to specific applications, manufacturers are finding innovative ways to achieve thermal management through material selection.