Powering Electric Motors with Insulation Tapes
As battery-electric vehicles reshape the future of mobility, innovation is accelerating across every component—from batteries to motors. While much attention has focused on battery technology, electric motors have quietly undergone a transformation of their own.
As of today, hairpin winding technology is increasingly being adopted in EV motors, particularly in high-performance and premium electric vehicles. However, conventional round-wire motors still dominate the broader EV market, especially in entry-level and mid-range models due to their lower manufacturing complexity and cost. As conventional round-wire motors still power most cost-sensitive and general-purpose EV applications, let us take a deeper look at how innovative tape solutions can help improve safety and performance of these electric motors.
EV traction motors are subject to stringent spatial, mechanical, and chemical constraints. They must deliver high torque and power density within a minimized envelope, necessitating compact architectures without compromising thermal or electrical performance. Unlike industrial motors, EV motors demand advanced insulation systems tailored to high-frequency switching, elevated temperatures, and aggressive chemical environments. Selecting insulation tapes requires careful evaluation of dielectric strength, thermal endurance, mechanical integrity, and chemical compatibility to ensure long-term reliability under dynamic load conditions.
Mechanical integrity is critical from the moment tapes are applied, as installation tension and long-term exposure to thermal cycling and vibration can lead to failure. Any tear or degradation — during assembly or service — can result in costly and unsafe electrical shorts. Additionally, proximity to transmission components exposes tapes to oils and greases, which can compromise structural integrity. Selecting the right combination of backing and adhesive is essential to ensure resistance to these contaminants and maintain performance.
Motors used in electric vehicles experience more starts and stops compared to industrial motors which typically run more continuously. Different tape designs help to improve the mechanical integrity of the tape to account for this increased activity. For instance, while taken individually, the mechanical strengths of PET (Polyethylene Terepthalate), PI (Polyimide) or PEN (Polyethylene naphthalate) may not be sufficient for the specific application, but in combining these substrates with glass filaments, glass cloth or other filmic materials, exceptional tensile strength can be achieved in this composite structure. Saint-Gobain® h-old® PS.25 is an example of how a PET tape reinforced with glass filaments can reach outstanding mechanical properties.
When choosing an electrically insulating tape for electric motors, it is critical to understand the chemicals that the tape will encounter. While the transmission in an EV is quite different from an ICE vehicle, the necessity for chemical compatibility is still important. For scenarios where the drive shaft from an electric motor is directly linked to the gear box, the tape used will meet the lubricating material; having a solution with proven chemical compatibility will contribute to the longevity of the electric motor performance.
An example of a product where the backing material improves chemical resistance is Saint-Gobain CHR® K.30, which combines silicone adhesive with a PEN film, resulting in an exceptional material when compared to other films like PET or PI.
The significant voltage fluctuations and spikes in an electric motor during acceleration and deceleration may require a range of breakdown voltage capabilities and corona resistance. Rather than over- or under-engineering, optimal performance can be expected when the tape material is chosen to meet the motor design and requirements in a good, better, best scenario where glass cloth is good, Aramid Paper / PET is better, and PI / PEN is best.
CHR PX.50 and 6601 are examples where different backings are combined to create high-performing products resulting in great flexibility and conformability with outstanding dielectrical and mechanical properties.
Advantages innovative tapes provide in electric motors
We have seen that special adhesive tapes can help to improve mechanical, chemical and electrical resistance of components and the entire electric motor. This can provide significant advantages for manufacturers and end-users alike.
Automakers can benefit from:
- improved reliability and durability, leading to reduced failure rates and warranty claims.
- greater design flexibility as high-performance tapes enable more compact motor designs by allowing tighter tolerances and higher slot fill factors.
- streamlined manufacturing, efficiency and cost optimization by preventing in-service failures (e.g., shorts due to insulation breakdown) which avoids costly recalls and repairs.
EV users on the other hand can benefit from:
- longer motor lifespan due to better insulation and therefore less degradation over time.
- improved safety because of reduced risks of electrical shorts or thermal runaway.
- consistent performance and maintained efficiency and output over time, contributing to better driving experience and range.
- reduced maintenance costs as high-end tapes minimize the need for motor servicing or replacements.
While you can’t fix a motor with tape, you can design a better one with it. Advanced insulation tapes are key to unlocking safer, more efficient EV motors. Customized solutions where the tape is optimized for specific application needs can be the cherry on the cake. If you are looking for solutions to design next-level EVs with conventional round-wire electric motors, talk to your tape expert and find out which solution will bring you on the right track.