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From efficiency to resilience: Exploring the benefits of TAU's PEEK coated wire



Electric mobility is playing a crucial role in the current automotive market. The need for an ecological solution and high-performance material led to the development of the DryCycle® process as a possible solution for the next generation of stator manufacturing. This article explains the advantages of PEEK-coated wires produced with DryCycle® technology and their main properties: strong polymer adhesion to copper surface, good elongation and flexibility, the main electrical characteristic in term of BDV and PDIV, as well as the stability of these parameters during thermal aging and bending.

PEEK coating

Wire Insulation

Electric motor



PEEK Magnet Wire - Tre Tau Engineering - June 08 2023
Download PDF • 1.25MB

Polyetheretherketone (PEEK) belongs to one of the most technologically advanced classes of thermoplastic polymers - polyaryletherketones (PAEK) [1]. PAEK, and especially PEEK, belong to the class of high temperature polymers.

PEEK is formed using a stiff aromatic polymer base, contributing to its high temperature and wear resistance compared to other polymers. Thanks to its chemical structure, this polymer combines many advantages.

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HIGH TEMPERATURE RESISTANCE PEEK has exceptional thermal stability, allowing it to withstand high temperatures up to 240-260°C for long periods of time, and short-term heat up to 310°C. This makes it suitable for applications where other polymers would collapse or melt.

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GOOD PROCESSABILITY PEEK can be theoretically processed using various methods: extrusion, vacuum forming, pressure molding, etc.

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FLAME RETARDANT PEEK is inherently flame retardant and meets most fire safety standards. It has low flammability and can self-extinguish, making it a safer option for insulating wires in potentially hazardous environments.

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CHEMICAL RESISTANCE PEEK is resistant to a wide range of chemicals, including acids and bases, as well as oil and boiling water. This allows the polymer to maintain its integrity and insulation properties even in aggressive environments. It's compatible with oil cooling technologies.

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DIELECTRIC PROPERTIES PEEK has excellent electrical insulation properties, its dielectric constant is 3.2, its dielectric strength is 20-24 kV/mm, which makes it an ideal material for wire insulation manufacturing.

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MECHANICAL PROPERTIES High tensile strength, excellent dimensional stability and ability to withstand mechanical stress, including abrasion and impact, without significant degradation, and flexibility. PEEK is used to create heavy-duty parts, turbines and compressors, as well as implants and bone prostheses.

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LOW WATER ABSORPTION PEEK has a very low water absorption, which reduces the risk of moisture related problems such as wire degradation, corrosion or changes in electrical conductivity. This property makes it suitable for use in wet or humid environments.

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The unfilled polymer has a relatively low density of about 1.4 g/cm3. This property is particularly useful in applications where weight reduction is required, such as in the aerospace or automotive industries.

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ECO FRIENDLY Since the polymer is a thermoplastic material, it can be recycled and reused.

Like most high performance materials, its main disadvantage is its high cost compared to other polymers such as PPS or PAI. As a result, its use is limited to areas where all the high-tech properties are required.

Chart that shows the industries and areas were PEEK can be used in
PEEK applications

The main characteristics of the three most popular high temperature engineering polymers, PEEK, PAI and PPS, and their comparison are shown in table [3]. It shows that PEEK has better thermal stability and can be used in higher temperature applications.

Table that shows the characteristics of the three most popular high temperature polymers: PPS, PAI and PEEK
High temperature polymers characteristics

table that shows the benefits of peek
Benefits of PEEK wire

The data presented previously refer to the polymer materials themselves. But after they are applied to the wire, their thermal classes of wires are as follows. Based on these values the benefits of PEEK wire are even clearer.

To produce a high-quality electric motor, it is essential to use strong, stable stator winding insulation. In fact, the failure rate data for electric motors shows that stator winding damage is the second most common cause of stator failure. According to statistics [4] up to 40% of electric motor failures are due to stator failure. The most common cause of failure is defects in its winding, which consists of polymer-coated copper wire. Therefore, by ensuring reliable wire insulation, it is possible to guarantee the proper functioning of the stator - the heart of the electric car.

PEEK Magnet Wire Tau Group
From efficiency to resilience: PEEK Magnet Wire

Another special and important property of PEEK is the peculiarity of its structure. Since PEEK is a semi-crystalline polymer, it is possible to modify its properties by changing its degree of crystallinity. It can be adjusted directly during the coating process, according to technological requirements.

The DryCycle® technology (patent EP3518255B1), which allows excellent control of the dynamics of the coating process, can exploit this feature of PEEK to obtain products with the desired properties. In addition, this technology avoids the use of the toxic solvents that are used in the conventional method of enamelling. This makes the process of creating magnetic wires safer and more environmentally friendly. This article presents test data from Tre Tau Engineering's DryCycle® wire made with commercially available PEEK with no fillers.

PEEK Magnet Wire - Tre Tau Engineering - June 08 2023
Download PDF • 1.25MB

About Tau

Tau is a technology company at the core of energy transition, decarbonization of energy and electrification of transport. Its patented technologies reconcile the necessity of sustainable, resource-minimizing manufacturing with the power, reliability and performance that electrification requires to enable smaller, greener, longer-lasting and more powerful motors, transformers and generators. Tau focuses on carbon-conscious protective coatings for high-performance and standard copper, aluminium and steel wires.

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