TIMs

*Updated version of the 2023 article.

Definition

TIMs (thermal interface materials) conduct heat while providing electrical insulation. They consist of an insulating polymer matrix as a carrier material, interspersed with solid thermally conductive particles such as metal oxides or metal hydroxides. TIMs can be used as adhesives, sealants and foams, but also as adhesive tapes, films, synthetic resins and mats. The goal is to develop electrically insulating functional materials with thermal conductivity that is 15 to 30 times higher than that of conventional plastics. 

Current applications and opportunities

Thermally conductive electrical insulators are used in batteries, electronic controls and transmissions in the automotive, electrical and electronic industries, as well as in medical technology. They conduct heat generated by electronic components to a cooling element, insulate the adjacent components in an assembly and fill performance-reducing air pockets as gap fillers. So TIMs are central to thermal management and also prevent electrical malfunctions such as short circuits.  

A growing market segment for TIMs is electromobility, where demand for batteries is high. Another future market is storage batteries in the likes of the building sector. Due to their thermal management, these materials have a direct influence on battery performance and lifespan, not to mention the charging time. Additionally, TIMs protect against overheating and thus have a safety aspect that should not be overlooked.  

Innovative TIMs enable lighter and more efficient batteries. They can be thermally conductive adhesives, film-based TIMs or standalone seals made from rubber compounds. They are lightweight and flexible, and their composition can be adapted to specific requirements and environments, which also enables the integration of additional material properties such as electromagnetic interference shielding. As components of battery storage systems, they speed up the energy transition from fossil fuels to renewable energy sources, which is impossible without expanded storage capacities. So TIMs contribute considerably to achieving sustainability goals. 

Challenges

Competitive and cost pressure in automotive manufacturing is forcing manufacturers to develop increasingly powerful and smaller batteries. This has consequences on battery box design. The development trend is shifting from conventional modular design (cell-to-module) to a cell design (cell-to-pack) or even to integrating individual battery cells directly into the body (cell-to-chassis). This allows both material and weight savings in battery boxes while achieving higher power density. However, this requires components to be bonded, which also changes the demands placed on TIMs. Compositions that have better adhesion and higher strength and that are sufficiently elastic to compensate for differences in components’ thermal expansion are being sought. 

However, the new design presents a major challenge for battery reusability and recycling. This is because trend towards direct installation of battery cells in the battery box or even directly on the chassis instead of in modules makes end-of-life material separations more difficult, because TIMs also connect the components in structural terms.  

Focus on industry

In the value chain, TIMs play a key role in end product manufacturing. Although Switzerland is not one of the leading countries in the automotive and battery industries due to its size and significance, it is an attractive location for the automotive supply industry. In this respect, materials for battery manufacturing are a rapidly growing market segment. Innovations in this area can therefore not only increase a company’s own value creation, but also consolidate its market position. 

Employees involved in TIM development and research must have in-depth knowledge of chemistry and materials science, with additional expertise in TIMs. However, a multidisciplinary mindset and knowledge of electronic components’ entire value chain are also required. In production, outstanding capabilities in plant and application technology are necessary, as the specific properties of TIMs place high demands on the production process. To counteract a looming shortage of skilled workers, leading producers are focusing on internal training and further education. 

International perspective

China is leading the development of new designs for car batteries. Europe, on the other hand, is struggling to keep pace with the rapid design cycles of Chinese industry. Companies based in Switzerland and other European countries that develop innovative battery designs and work on TIMs are technological leaders. However, high development costs and the low prices of Chinese production have a negative impact on their competitiveness on the mass market. In the automotive supply industry, however, there are certainly niches for high-quality products that can be filled.  

Future applications

Development is progressing primarily within existing fields of application. Increasing miniaturisation and the associated increase in energy densities in electronic components also leads to new demands being placed on thermally conductive insulating materials. This trend particularly affects electromobility, as weight and volume savings are less relevant for battery storage systems in buildings or housing estates, for example. A major challenge is developing TIMs that can be easily dismantled and recycled at the end of battery lifecycles to enable complete battery circularity. 

Thermally conductive electrical insulators are particularly important for the automotive, electrical and electronics industries and play a key role in electromobility. TIMs improve battery performance and lifespan and contribute to safety. In Switzerland, development of this technology is driven primarily by industrial research. Innovative TIMs can speed up the energy transition and contribute to achieving sustainability goals.