Thermal Conductive Gap Fillers for Electronics and Battery Assemblies
Haktak supplies thermal conductive gap fillers for assemblies that need to bridge uneven gaps, reduce thermal resistance and maintain reliable contact between heat sources and cooling structures.
What Are Thermal Conductive Gap Fillers?
Thermal conductive gap fillers are soft thermal interface materials designed to fill air gaps and conduct heat between components, boards, modules, housings, heat sinks or cooling plates. They can be supplied as liquid gap fillers, dispensable gels, pre-formed pads, sheets or custom die-cut parts.
Bridge uneven gaps
Fill tolerance stack-up between components, heat spreaders, enclosures and cooling plates.
Improve heat transfer
Replace trapped air with a thermally conductive path that lowers thermal resistance.
Support production
Use dispensable, sheet, roll or die-cut formats to match manual or automated assembly.
Where Thermal Conductive Gap Fillers Are Used
Gap fillers are used in assemblies where air gaps, height variation or low contact pressure make direct contact unreliable. Haktak can recommend materials for electronic, battery, power and industrial designs.
EV Battery Packs
Between cells, modules, cooling plates, trays and BMS electronics where gap tolerance and thermal contact matter.
Power Electronics
For MOSFETs, IGBTs, converters, chargers and power supplies transferring heat to housings or heat sinks.
LED and Displays
For LED boards, backlights, displays and aluminum housings needing clean placement and stable heat flow.
Industrial Modules
For controllers, sensors, telecom units and rugged electronics with variable surface gaps.
How to Choose a Thermal Conductive Gap Filler
A thermal gap filler should be selected around the final compressed or cured state, not only the advertised W/mK. The real result depends on bond line thickness, pressure, contact area, dispensing volume, material hardness and reliability behavior.
Types of Thermal Conductive Gap Fillers
Thermal conductive gap fillers are not one single material. The best option depends on whether the assembly needs dispensing, pre-formed placement, reworkability, low stress, high dielectric strength or a custom production format.
Liquid Gap Fillers
Dispensable materials used for complex surfaces, variable gaps and automated production lines. They are useful when pad inventory or die-cut variation becomes difficult to manage.
Thermal Gap Filler Pads
Soft pre-formed pads supplied in sheets, rolls or die-cut shapes. They provide controlled thickness, clean handling and repeatable placement.
Thermal Gels
Soft gel-like materials that conform under light pressure and can help reduce stress on components while maintaining thermal contact.
Custom Hybrid Formats
Application-specific materials supplied as pads, strips, gaskets, dispensed beads or placement-ready parts for battery and electronics assembly.
Liquid Gap Filler vs Thermal Gap Filler Pad
Both formats fill gaps and move heat, but they fit different production and design needs. Liquid gap fillers handle complex geometry and automated dispensing, while gap filler pads provide defined thickness and clean placement.
| Format | Best Use | Strengths | Watch Points |
|---|---|---|---|
| Liquid gap filler | Variable gaps, complex surfaces, automated dispensing and large area interfaces. | Excellent conformance, inventory flexibility and low assembly stress. | Requires dispensing control, cure or set management and process validation. |
| Thermal gap filler pad | Defined gaps, clean placement, die-cut shapes and repeatable manual assembly. | Controlled thickness, easy handling and no liquid process. | Thickness and hardness must match tolerance and pressure limits. |
| Thermal grease | Very thin flat interfaces with strong clamping pressure. | Low bond line and strong wetting at thin gaps. | Can migrate, pump out or require careful application volume. |
| Thermal adhesive | Interfaces needing bonding plus heat transfer. | Mechanical attachment and thermal path in one material. | Reworkability, cure, stress and bond strength must be validated. |
Key Properties That Affect Gap Filler Performance
A gap filler data sheet should be read as a system guide, not a simple ranking list. The material that performs best in the assembly is the one that balances thermal conductivity, thickness, pressure, contact quality and long-term reliability.
Thermal Gap Filler Design and Validation Process
A gap filler should be validated in the real mechanical and thermal stack-up. Testing only a data sheet value can miss compression, contact, dispensing and long-term stability issues.
Measure the gap
Record min, nominal and max gap across components, boards, housings and cooling structures.
Select format
Choose liquid, gel, sheet, die-cut pad or custom material based on assembly process.
Test thermal result
Validate temperature drop or impedance at actual thickness, pressure and contact area.
Check reliability
Run aging, thermal cycling, vibration, compression and material compatibility tests.
Thermal Gap Filler Selection by Application
Different electronics programs care about different risks. EV battery packs may prioritize compression and reliability, while power electronics may focus on dielectric strength, thermal impedance and high-temperature aging.
| Application | Typical Gap Filler Role | Important Requirements | Engineering Notes |
|---|---|---|---|
| EV battery packs | Fill gaps between cells, modules, trays, cooling plates and pack electronics. | Low stress, stable compression, dielectric safety and thermal cycling resistance. | Validate contact after vibration, aging and repeated temperature cycling. |
| Power electronics | Move heat from MOSFETs, IGBTs, converters and power modules to heat sinks or housings. | Thermal impedance, dielectric strength, high-temperature stability and pump-out resistance. | Test at real clamping force and operating temperature. |
| LED lighting | Improve heat transfer from LED boards and drivers to aluminum housings. | Clean placement, stable thickness, long operating life and low assembly variation. | Confirm pad or liquid format based on volume and placement process. |
| Telecom equipment | Bridge gaps in routers, modules, RF equipment and outdoor electronics. | Thermal cycling, moisture exposure, dielectric behavior and long service life. | Consider liquid materials for complex internal geometries. |
| Industrial controls | Support sensors, controllers, drives, inverters and ruggedized modules. | Vibration resistance, temperature stability and material compatibility. | Prototype with the real housing and fastener design. |
Information Needed for a Custom Thermal Gap Filler
For faster recommendation, share the full assembly context rather than only W/mK. Haktak can help select or customize a material around the real thermal, mechanical and production requirements.
- Heat source, cooling surface and contact area.
- Minimum, nominal and maximum gap after assembly.
- Target W/mK, thermal impedance or temperature drop.
- Compression pressure, stress limit or clamping method.
- Dispensing, sheet, roll, cartridge or die-cut format.
- Operating temperature, aging, vibration and cycling profile.
Common Thermal Gap Filler Selection Mistakes
Many thermal problems come from choosing a material around a single number instead of the real assembly. Avoiding these mistakes can reduce prototype rounds and improve production reliability.
Choosing only by W/mK
Higher W/mK does not always reduce temperature if the bond line is too thick, the pressure is too low or contact is poor.
Ignoring minimum gap
A material selected for the maximum gap may create too much stress at the minimum gap if compression is not checked.
Skipping process validation
Dispensing volume, bead stability, liner removal, die-cut handling and placement tolerance affect real production results.
Testing flat coupons only
Flat coupon tests do not always show how the material behaves on uneven housings, curved surfaces or real PCB layouts.
Missing dielectric margin
Power devices and battery systems may require insulation performance after compression, aging and contamination exposure.
Forgetting long-term movement
Pump-out, oil bleed, compression set and thermal cycling can reduce contact and change thermal performance over time.
How to Test Thermal Conductive Gap Fillers
Testing should represent the real assembly as closely as possible. Haktak can support material selection with data from gap range, contact pressure, operating temperature and reliability profile.
Thermal test
Measure component temperature or thermal impedance at final bond line thickness and pressure.
Mechanical test
Check compression force, stress on components, material recovery and tolerance coverage.
Process test
Validate dispensing, placement, liner release, cure or set behavior, rework and assembly time.
Aging test
Run heat aging, humidity, thermal cycling, vibration and storage tests to confirm long-term stability.
Custom Thermal Conductive Gap Fillers for Production
Haktak supports thermal conductive gap filler selection and customization for standard products, engineering samples and production assembly. Material options can be matched to gap size, hardness, thermal conductivity, tack, dielectric strength and application format.
Material property matching
Match thermal conductivity, softness, viscosity or thickness, dielectric behavior and reliability requirements.
Process-ready formats
Support cartridges, pails, sheets, rolls, die-cut parts, liners or custom packaging for assembly flow.
Engineering sample support
Use drawings, thermal targets and process details to prepare samples for validation before production.
How to Request Thermal Gap Filler Samples from Haktak
A good sample request should include the information needed to recommend both material chemistry and supply format. This helps avoid receiving a material that looks good on a data sheet but does not fit the assembly.
Need a Thermal Conductive Gap Filler for Your Assembly?
Send your application, gap range, thermal target, process method and reliability requirements. Haktak can recommend a liquid gap filler, gap filler pad or custom thermal material format.
Thermal Conductive Gap Fillers FAQ
What is a thermal conductive gap filler?
It is a soft thermal interface material that fills air gaps and transfers heat between components and cooling surfaces.
When should I use a liquid gap filler?
Use liquid gap filler for variable gaps, complex surfaces, automated dispensing or large interfaces where a fixed pad may not conform well.
When should I use a thermal gap filler pad?
Use a pad when the gap is defined, clean placement is important and production benefits from die-cut or sheet formats.
Is higher W/mK always better?
No. Final thickness, pressure, contact area, hardness and reliability can matter as much as bulk thermal conductivity.
Can Haktak customize thermal gap fillers?
Yes. Customization can include thermal conductivity, hardness, viscosity, thickness, tack, liner, shape and supply format.