Thermal Gap Pads vs Thermal Conductive Paste

Thermal Interface Materials (TIM) help move heat between components. Up to 90% of the gap in contact areas is filled by TIM. This makes it critical.So to know the difference between Thermal Gap Pads and Thermal Conductive Paste.

One main job of TIM is to move heat away from components. This helps protect them from heat damage. By using TIM, heat is spread out better, keeping devices cool and working well.

For TIM to work well, it needs two important qualities. Thermal impedance shows how good it is at moving heat. Thermal conductivity shows how well it can conduct heat itself. These qualities affect how fast and well heat is moved.

By improving these qualities, TIM helps electronic devices cool down. This keeps devices stable, lasts longer, and works better. It’s key for keeping devices running smoothly.

thermal paste vs thermal pad: Key Differences

It’s important to know the differences between thermal pads and thermal pastes for good thermal management in EVs and ESS. The right choice depends on several factors like their makeup, physical traits, and how well they perform.

Composition and Physical Properties

Thermal pads are made from a silicone-based material that’s easy to apply. They come in different thicknesses and are known for their simplicity and reliability. On the other hand, thermal pastes are applied as a paste and then dried to form a solid interface. The type of thermal paste can affect its thermal conductivity.

Thermal Conductivity and Performance Metrics

The thermal conductivity of a TIM is key, showing how well it can move heat. Thermal pads usually have a conductivity of 1 to 6.5 W/mK. On the other hand, top-notch thermal pastes can reach up to 8.5 W/mK, perfect for EV power electronics.

It’s also vital to remember that thinner TIMs are better at cooling. This is because they can spread heat more efficiently.

Our studies show that thermal pads offer steady performance, but thermal pastes can do better when applied thinly. Thermal impedance is a better metric than conductivity for picking between pads and pastes for EV/ESS needs.

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Thermal Gap Pads

Thermal conductive pad is a solid material, which is a thermally conductive material that provides a consistent thickness. They are often pre-cut to provide a consistent thickness for different applications. This ensures consistent pressure distribution between components. Although it cannot fill every small gap like thermal paste, it is easier to install. In addition, this material is extremely resistant to high temperatures as well as moisture retention. It is often used in applications where ease of use and electrical insulation are critical.

Find more information at What are Thermal Pads

Advantages of Pads

Ease of Application: Thermally conductive pads are easier to apply than solder pastes that require specialised application equipment. They simply need to be placed on the application with relative pressure.

Ease of Manufacturing: Thermally conductive pads are used in heating elements to avoid pad bonding, making the manufacturer’s job easier. In contrast, thermally conductive pads are less likely to move out of their initial position than thermally conductive pastes.

Standardised heat dissipation capability: Compared to liquid thermal paste, thermal pads have a more standardised heat dissipation capability on the pad surface, making standardisation easier to achieve. Thermal pads respond to the temperature of the heating component by softening after application, thus filling the interface gap on the application surface.

Gap Filling Capabilities: Pads are great at filling tiny gaps. This improves contact and boosts system performance.

Vibration Dampening Properties: Pads also dampen vibrations, important in electric vehicles. This helps extend the life of sensitive parts.

Disadvantages of Pads

Adhesion Issues: When a thermally conductive pad adheres to a heat sink, it is usually moulded to one of the heat-generating surfaces it is in contact with. This means that if the heat sink or other nearby components move, the pad must be replaced.

Single Use: Thermal pads cannot be used multiple times and once removed, each component needs to be handled very carefully, especially if the pad adheres to other components of the application. This can add cost and complexity to the manufacturing process.

Lower Thermal Conductivity: It is less thermally conductive compared to thermal paste.

thermal conductive paste

Thermal conductive paste, also known as thermally conductive grease or thermal compound, is a common thermal interface material. It is an adhesive material that effectively fills small defects at the interface. For example, it can be used to fill air gaps between heating elements and heat sinks to provide better interfacial heat transfer. It has better thermal conductivity than other interface materials. It is also cheaper than thermal pads. He also has different types to choose from depending on the needs.

Advantages

Multiple application methods: Compared to thermal pads, thermal paste offers a similar solution, but as a liquid, it can be used in a variety of ways. Through dispensers (syringes, tubes, etc.), the paste can be applied directly to the central processing unit (CPU) or heat sink, filling even the smallest interfacial air gaps to ensure effective heat transfer and preservation.

Stability: Thermally conductive pastes do not flow and remain stable under strong vibrations. They are able to maintain stability over time.

EFFICIENCY: Since the heat transfer capacity is inversely proportional to the amount of thermal interface material used, very little thermally conductive paste is required, e.g., THERM-A-GAP GEL30 or GEL8010. this allows for a low thermal impedance at both thin gaps and thick gaps, using common heat sinks.

Low Outgassing: When products are applied near cameras or optics, it is critical to select a thermal paste that meets NASA outgassing standards. Low outgassing ensures that outgassed silicone will not condense on cameras or other optical devices.

Conformability to Irregular Surfaces: Paste can fit to odd shapes better than pads. This is really helpful in EV/ESS where parts can be tricky to fit.

Cost-Effectiveness at Scale: Thermal paste is cheaper than pads for big production runs. It saves money because you use less of it, and machines can apply it faster.

Disadvantages

Application Technical Requirements: When using a thermally conductive paste, it is important to ensure that the entire surface area is covered as needed and that an adequate amount is used. Whilst less is usually better, using too little will not adequately fill any air gaps that may exist.

Liquid state can lead to mess: The liquid nature of thermally conductive pastes can lead to mess and wasted material during application. Therefore, care and precision are key to ensure that the right amount of thermal paste is applied accurately to avoid wastage.

Difficult to maintain: Thermal paste dries out over time due to its poor moisturizing properties. Therefore it needs to be applied regularly to maintain the thermal performance of the component.

Performance Comparison: Real-World Testing

Testing in real-world settings is key to see how thermal materials work in EV/ESS. It shows how they handle different conditions.

Temperature Management Under Load: Thermal paste does better in high-load situations because of its good heat transfer. But, pads are easier to handle and perform consistently.

Long-Term Reliability in EV/ESS Environments: Good thermal management can make EV/ESS parts last longer. It keeps the temperature steady, which is good for parts’ lifespan.

Impact on Component Lifespan: Choosing between paste and pads affects how long EV/ESS parts last. It helps avoid damage to important parts like IGBTs and MOSFETs.

Which is better:thermal pad vs thermal paste

Can I use thermal paste instead of thermal pads?

Thermal paste or gel can be a reasonable alternative to thermal pads. Compared to thermal pads, thermal paste offers automation capabilities, lower impedance (in the case of some materials), and the ability to be more consistent on irregular surfaces. The use of thermal paste may need to be considered in the following situations:

Higher Production Demand: If your production demand exceeds 5,000 parts/year, a thermally conductive paste may be a more appropriate choice.

Complex Pattern Designs: If the part design involves complex patterns, thermal paste may be more convenient for automated applications.

Part fragility: If the part is fragile because the solder paste produces low mechanical stress, a thermally conductive paste may be more suitable.

Suppose the intent is to replace a thermal pad with a thermally conductive paste. In that case, some recommended products include Chomerics Therm-a-Gap Gel 75 (high thermal conductivity), Gel 30, or 8010 (used in automotive applications with ultra-low compression).

Are thermal pads better than thermal paste?

The choice between thermal pads and thermal paste is not a clear-cut “better” choice, but rather depends on the specific needs of the application. Thermal pads have historically been used for a wide range of applications and are particularly good at vibration suppression and space filling. Their hand-applied nature makes them potentially more challenging in terms of surface consistency.

In contrast, thermal paste offers automation capabilities, lower impedance, and the ability to provide higher consistency on irregular surfaces. As a result, thermal paste may be more appropriate where production needs are greater, part design is more complex, or part fragility is higher.

Overall, the choice depends on the requirements of the particular application, and the advantages of both thermal pads and thermal paste need to be considered together and the choice made accordingly.

Conclusion

Choosing the right thermal management for EV/ESS is important. There’s no one-size-fits-all solution. You need to think about your system’s thermal needs and pick the best material.

At trumonytechs, we know how hard it is to pick the right thermal material. Many EV/ESS designs use a mix of thermal paste and pads. Paste is for high heat, and pads are for easier assembly or filling gaps.

We suggest looking at your thermal management system as a whole. Whether you pick paste for its conductivity or pads for ease, trumonytechs has top solutions. Our team can work with you to improve your EV/ESS systems. Contact us to see how our materials can help your electric vehicle and energy storage systems.

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