How Thermal Interface Materials Boost EV Battery Life
Maximizing the energy density of EV battery packs is a top priority for engineers developing next-generation electric mobility. Energy density refers to the amount of energy a battery can store relative to its weight or volume—enabling longer driving ranges without increasing battery size or mass.
However, higher energy density introduces new engineering challenges, particularly in thermal management. As fast charging, high-performance EVs, and stricter safety regulations become the norm, battery longevity and thermal stability are under increasing scrutiny. In this article, we explore how advanced thermal interface materials (TIMs) are helping address these challenges and extend the performance and lifespan of EV batteries.
Within the battery pack, heat is generated not only during the operation of the battery. By attempting to maximize charging speed in fast-charging applications, the high voltage and current used also produces heat inside the battery pack. With growing energy density and the race for even shorter fast-charging times, heat and even overheating can become a serious challenge in designing battery packs. In addition, batteries operate more efficiently and retain their capacity longer if their environment is maintained within a narrow range of temperature.
Therefore, heat dissipation and thermal management are growing in importance and energy transfer between battery components and cooling devices is getting in the focus. Thermal interface materials (TIMs) are used to dissipate heat away from cells and modules to spread heat between the array of cells and the cooling plate, thereby conducting heat and providing a thermal path for heat to flow away from the battery.
To lower temperatures and maintain ideal operating conditions, thermally conductive material(s) with high dielectric strength are used as gap fillers (also commonly referred to as thermal pads), conforming to rough, curved, uneven or dynamic surfaces. This provides a thermally conductive pathway to exhaust excess heat and keep components within operating specifications, even if the component surfaces present challenges. The thermal pad is intended to maintain maximum surface area contact between the battery and the heat sink, minimizing potential thermal impedance and providing the shortest pathway to conduct the heat away.
Thermal interface materials are widely characterized by their product specifications, like thermal conductivity, impedance, and electrical resistance. Thermal conductivity measures how efficiently heat flows through the material, while thermal impedance reflects the total resistance to heat transfer across the interface, including surface contact resistance. Electrical resistance is also critical in applications where insulation is needed to prevent electrical shorts between components.
Besides those, there are additional features like conformability, surface characteristics like tack level and the ability to re-work during the assembly process that need to be considered.
Battery-electric vehicles are the fastest growing segment in mobility these days. With many countries—including the EU, UK, China, and several U.S. states—planning to ban new fossil-fuel vehicle sales by 2035 or earlier, the shift to electric mobility is accelerating globally.
This leads to innovation, development and need in other areas, too. As mentioned earlier, fast charging is growing rapidly as higher heat loads require TIMs with faster thermal response and higher conductivity.
New battery designs are being developed, including Cell-to-Pack (CTP) and Cell-to-Chassis (CTC) Designs where less room for cooling systems increases reliance on TIMs.
New materials like the push for non-silicone, recyclable, or low-VOC TIMs or advanced technologies like Smart Thermal Management where sensors or phase-change materials are integrated are currently under development and underline the importance of innovative TIM materials for many EV battery designs.
We have seen that heat management in EV batteries with high energy density is crucial with current battery technology. Let’s have a closer look at the benefits innovative TIM materials provide for OEMs, engineers and the end user.
OEMs mainly benefit from improved battery safety, longer lifespan, and better warranty performance by using TIM materials that help to maintain ideal operating conditions of the battery even under extreme situations.
For Engineers, new TIM materials offer greater design flexibility, easier assembly, and rework, opening new opportunities to further increase energy density or develop new battery technologies.
End users benefit from more consistent range, safer operation, and longer battery life if high-performance TIM are used in the battery design.
TIM materials are already used in most EV battery designs, and we have seen that they are essential components in the design of next-generation battery systems. By selecting the right TIMs early in the design process, OEMs and engineers can unlock greater efficiency, reliability, and flexibility, while meeting the demands of a rapidly electrifying mobility landscape. In this context, talk to your tape experts and find out why TIMs are not just materials—but are enablers of innovation.