As the global automotive industry accelerates toward electrification, lightweighting has emerged as the critical pathway to extending EV range and improving overall efficiency. PEEK film (polyetheretherketone film) stands at the forefront of this transformation, offering an unparalleled combination of properties that make it indispensable for modern automotive applications. With a density仅为 metals' fraction, tensile yield strength of 93 MPa, continuous operating temperature of 260°C, and exceptional dielectric performance, PEEK film delivers weight reduction without compromising mechanical integrity or thermal stability. This article explores the material properties, key automotive applications—including motor slot liners, battery insulation layers, and spacer components—and the growing market trajectory of PEEK film in the electric vehicle revolution.
The first quarter of this year saw domestic automotive sales decline by 5% year-over-year, yet new energy vehicle (NEV) penetration rates surpassed 60% for the first time. This milestone underscores an undeniable truth: the future of transportation is electric. However, range anxiety remains one of the most significant barriers to widespread EV adoption. The solution? Lightweighting—and PEEK film is emerging as the material that makes it possible.
Automotive lightweighting is the core pathway to extending range and reducing energy consumption. Every kilogram of weight saved translates directly to increased driving distance, improved battery efficiency, and enhanced vehicle performance. Among the advanced materials enabling this transformation, polyetheretherketone (PEEK) film stands apart as a high-performance engineering plastic that delivers exceptional strength-to-weight ratios, thermal stability, and electrical insulation properties.
PEEK film (polyetheretherketone film) is a semi-crystalline thermoplastic film derived from one of the highest-performing polymers in the world. PEEK is widely regarded as one of the highest performing thermoplastics globally, characterized by its linear, aromatic, semi-crystalline structure that delivers outstanding mechanical, thermal, and chemical resistance.
Lightweight Construction:
PEEK film boasts a density仅为金属的几分之一（仅为金属密度的几分之一）, delivering dramatic weight reduction benefits. Compared to metals, PEEK-based materials offer equivalent strength at up to 40% weight reduction, with specific strength and stiffness many times that of metals and alloys. This makes PEEK film an ideal replacement for stainless steel and other metals for weight reduction without sacrificing performance.
Superior Mechanical Strength:
With a tensile yield strength of 93 MPa, PEEK film meets the load requirements of high-frequency moving components. Advanced processing techniques can achieve even higher performance—biaxially stretched PEEK film can reach tensile strengths of 156.7 MPa, nearly 2.5 times that of unstretched film. Under optimized conditions, stretched PEEK film has demonstrated tensile strengths up to 333 MPa.
Exceptional Thermal Stability:
PEEK film maintains continuous operating temperatures up to 260°C, with a melting point of 343°C and glass transition temperature of 143°C. This makes PEEK film suitable for engine compartment and other high-temperature automotive environments where traditional materials would fail. The material also achieves a UL-recognized V-0 flammability rating.
Outstanding Electrical Insulation:
PEEK film delivers exceptional dielectric performance, with dielectric strength reaching up to 190 kV/mm. This makes PEEK film ideal for primary and secondary insulation concepts in 800+ volt electric machines.
Chemical Resistance and Durability:
PEEK film exhibits excellent resistance to automatic transmission fluids (ATF), chemicals, and hydrolysis. It maintains uniform properties over a wide frequency and temperature range while demonstrating low moisture absorption and permeability.
One of the most transformative applications of PEEK film is in electric motor slot liners. Ajedium™ PEEK film technology, developed by Syensqo, has been recognized with the prestigious 2025 Automotive News PACE Pilot Award for advancing EV performance and sustainability.
These spiral-wound slot liner tubes leverage the high-performance properties of PEEK films, providing superior insulation for electric motors. The unique product design enhances e-motor efficiency by up to 2%, enabling a more effective copper fill factor and improved heat dissipation.
PEEK film has been successfully tested with 800-volt systems, demonstrating superior copper fill and heat dissipation capabilities compared to traditional aramid paper alternatives. This enables manufacturers to downsize e-motor and battery designs while eliminating the need for conventional moisture management systems.
The lightweighting impact is substantial: Ajedium™ PEEK Film slot liners offer a potential mass reduction of 12 kg in the battery pack and 4 kg in the e-motor of EVs compared to traditional laminates. By achieving the same electrical resistance at only two-thirds of the typical laminate thickness, innovative PEEK slot liners increase available stator slot space for additional magnet wire and higher copper slot fill factors.
PEEK film serves as a critical insulation layer for electric vehicle batteries. The material's exceptional dielectric strength, thermal stability, and chemical resistance make it ideal for battery module insulation, where reliability and safety are paramount.
In battery applications, PEEK insulation film provides robust, repeatable insulation that maintains clearances stable without adding weight. The material's ability to withstand high temperatures and resist chemical degradation ensures long-term performance in demanding EV battery environments.
PEEK film is widely used in motors, drives, and battery modules for slot liners, phase insulation, and stiff spacers. The material's mechanical strength and dimensional stability make it ideal for applications where thin film needs extra backbone.
PEEK film provides high-performance insulation for wire, cable, and protective sheaths. The material's lightweight nature and extreme durability make it suitable for aerospace harnessing and industrial electronics.
With continuous operating temperatures up to 260°C, PEEK film is ideal for engine compartment components where traditional polymers would fail. Under-hood high-performance polymers like PEEK deliver strength and heat resistance where metals would add too much weight.
PEEK film offers metal-equivalent strength at a fraction of the weight. While metals add substantial mass to vehicles, PEEK film provides:
Traditional aramid paper alternatives cannot match the performance of PEEK film in modern EV applications:
The global PEEK film market is experiencing robust growth, driven by expanding adoption in weight-sensitive and performance-critical industries. According to QYResearch, the global polyetheretherketone (PEEK) film market reached approximately $179 million in 2025 and is projected to reach $271 million by 2032, growing at a compound annual growth rate (CAGR) of 6.2%.
Industry recognition underscores the transformative potential of PEEK film technology:
As Brian Baleno, Director of Global Business Development and Program Management at Syensqo, stated: "Our Ajedium™ PEEK has been successfully tested with 800 volt systems, demonstrating superior copper fill and heat dissipation capabilities compared to traditional aramid paper alternatives".
The automotive industry is undergoing a transformative shift toward battery electric vehicles, necessitating innovative materials that can handle higher voltages and perform better. PEEK film is uniquely positioned to meet these demands.
Key trends driving PEEK film adoption include:
As EV manufacturers move from 400-volt to 800-volt or higher systems, conventional paper laminate slot liners can no longer meet the challenges. PEEK film provides the thermal, electrical, and mechanical performance required for next-generation electric powertrains.
The material also contributes to sustainability through:
PEEK film (polyetheretherketone film) represents a paradigm shift in automotive materials engineering. With its exceptional lightweighting capabilities, high-temperature resistance up to 260°C, tensile strength of 93 MPa, and superior electrical insulation properties, PEEK film enables the next generation of electric vehicles to achieve greater range, higher efficiency, and enhanced performance.
From motor slot liners and battery insulation layers to spacers and phase insulation, PEEK film is the material of choice for engineers seeking to reduce weight without compromising reliability. As the global automotive industry continues its electrification journey, the demand for high-performance PEEK film will only accelerate.
Whether you are an automotive OEM, Tier 1 supplier, or component manufacturer, PEEK film offers the lightweight, durable, and thermally stable solution your electric vehicle designs require. The future of automotive lightweighting is here—and it's made of PEEK.
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