by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

The Role of Polymer Bearings in Electrified Equipment and EV Platforms

With the steady demand for electrified equipment and EV (Electric Vehicle) platforms, engineers are being forced to rethink their bearing designs. More specifically, traditional metal bearings involve serious challenges in high-voltage environments, including vulnerability to electrical erosion, heavy weight, and the need for constant lubrication. However, engineered-grade polymer bearings have emerged as a viable replacement, offering unique physical and chemical properties that address challenges posed by battery-powered mobility and high-voltage architectures.

Solutions Addressed by Polymer Bearings in Electrified Equipment

There are four challenges posed by electrified systems that polymer bearings can solve. The first is electrical insulation. Metal bearings carry electricity, while unfilled polymers are non-conductive. This eliminates issues with electrical pitting, fluting, and spark erosion. This eliminates the most common types of damage caused by electrical flow.

Another obvious benefit of polymer bearings is the weight savings. Polymers can be up to 80% lighter than traditional steel and bronze bearings. And in applications such as EV, every bit of weight savings adds up to benefits like improved overall efficiency and extended battery range.

Polymer bearings are going to run more quietly as they absorb shock and dampen vibrations. For EV, this means an NVH (Noise, Vibration, and Harshness) reduction that leads to a quieter, more pleasant ride.

In addition, there are types of polymers that are self-lubricating and allow for dry running. This not only reduces maintenance requirements but also eliminates parasitic drag from lubricant shear and the need for greases that can attract contamination. but enhances bearing reliability.

Polymer bearings are not going to rust, which means they are extremely reliable for situations like exterior chassis components exposed to weather. They also work well for thermal management systems that involve glycol-based coolants and water.

Types of Polymers, Features, and Applications

High-Performance Polymers

There are several top-tier plastics that are used inside or adjacent to electrical drive units. These include PI, PEEK, PPS, and PAI.

Polyimide (PI / Vespel) provides excellent dielectric strength and can withstand massive bearing loads even at extreme temperatures without experiencing creep. PI works best in high-voltage applications that demand maximum insulation. PI bearings work very well for insulating bearing sleeves inside EV traction motors.

PEEK (Polyetheretherketone) is known for its outstanding chemical resistance and high-temperature performance (up to 480°F continuous). PEEK bearings work very well in systems that are continuously exposed to aggressive coolants, fuels, and synthetic fluids, such as thermal management coolant pumps, high-speed actuators, and components submerged in e-axle or automatic transmission fluids.

PPS (Polyphenylene Sulfide) stands out because of its excellent chemical compatibility, low rigidity, low moisture absorption, and excellent thermal stability up to 400°F, as well as being a more cost-effective alternative to PEEK. The best areas for PPS bearings are applications requiring table electrical and mechanical performance under heat and chemical exposure. PPS bearings are often found with under-hood actuators, valves, and plastic over-moldings for deep groove ball bearings in eAxles.

PAI (Polyamide-Imide) is the highest-strength thermoplastic available for bearings. PAI bearings exhibit exceptional thermal resistance (up to 500°F) and extreme compressive strength (up to 1,000 psi). These bearings do their best work in extreme load-bearing environments where mechanical strength cannot be compromised. They are often found in high-temperature turbine environments, compressors, and heavy-duty robotic joints.

Engineering Polyamides

Engineers in search of a balance of cost-effectiveness, toughness, and reduced weight, an engineering Polyamide might be the best option.

PA46 and PA66 (Nylon) are able to resist deformation even at extreme speeds and are usually able to reduce the rotating mass of bearing assemblies. In addition, PA46 and PA66 are ideal for high-speed internal moving parts. In fact, an excellent example of usage would be bearing cages that hold steel or ceramic ball bearings inside EV traction motors spinning up to 30,000 RPM.

Fiber-Reinforced Nylon is another option when it comes to engineering polyamides. Filled solutions involve reinforcement with glass or carbon fibers in order to significantly increase mechanical and structural strength. Fiber-reinforced bearings are excellent for applications that require heavy-duty, load-bearing structural joints. Examples include replacements for the heavier metal bearings found in EV chassis, steering columns, and suspension components.

Low-Friction & Solid Lubricant Polymers

There are a couple of engineering polymers that provide exceptionally low friction and are self-lubricating.

PTFE (Polytetrafluoroethylene / Teflon): PTFE is the lowest-friction engineering material available with near-universal chemical resistance and electrical isolation properties. Because it has poor mechanical strength on its own, PTFE is often compounded with glass, carbon, or bronze fillers to handle loads. PTFE bearings are an excellent choice for low-load, low-to-moderate-speed applications or other operating environments requiring entirely dry operation. This includes Planetary gearsets, cooling pumps, and robotic automation gearboxes.

POM (Polyacetal / Acetal): POM is a valid option for cabins and interior systems where NVH control (eliminating squeaks/rattles) and avoiding messy liquid greases is paramount. It offers high rigidity and very low moisture absorption, and when combined with PTFE, it provides an ultra-smooth, silent glide. POM bearings can be found in EV pedal boxes, seat tracks, hinges, and steering columns.

UHMW-PE (Ultra-High Molecular Weight Polyethylene) offers extreme abrasion resistance and excellent durability, which is ideal for sliding applications that involve high wear. UHMW-PE bearings are commonly used in automated robotic manufacturing equipment for assembling EV battery packs.

MaterialElectrical insulationTemp. resistanceLoad capacityChemical resistanceSelf-lubricatingWeight savings
High-performance polymers
PI (Vespel)★★★★★★★★★☆★★★★☆★★★★☆★☆☆☆☆★★★☆☆
PEEK★★★★★★★★★☆★★★☆☆★★★★★★☆☆☆☆★★★☆☆
PPS★★★★☆★★★★☆★★★☆☆★★★★☆★☆☆☆☆★★★☆☆
PAI★★★★☆★★★★★★★★★★★★★★☆★☆☆☆☆★★★☆☆
Engineering polyamides
PA46/PA66 (Nylon)★★★☆☆★★★☆☆★★★☆☆★★☆☆☆★★☆☆☆★★★★☆
Fiber-reinforced nylon★★★☆☆★★★☆☆★★★★☆★★☆☆☆★★☆☆☆★★★☆☆
Low-friction & self-lubricating
PTFE (Teflon)★★★★★★★★☆☆★★☆☆☆★★★★★★★★★★★★★☆☆
POM (Acetal)★★★☆☆★★☆☆☆★★★☆☆★★★☆☆★★★☆☆★★★☆☆
UHMW-PE★★☆☆☆★★☆☆☆★★☆☆☆★★★☆☆★★★☆☆★★★★☆

Conclusion

Polymer bearings have been proven to be much more than just a lightweight substitute for metal. Polymer bearings in electrified equipment and EV platforms are an active efficiency enabler. And by minimizing friction, managing heat, preventing parasitic electrical erosion, and eliminating liquid lubrication, polymer bearings can significantly extend the lifespan and reliability of electric drivetrains.

As the EV industry rapidly transitions from 400V to 800V architectures, the challenges of electrical discharge and thermal management will double. Highly engineered polymer bearings, especially insulating composites and over-molded solutions, will be critical in maintaining the efficiency, safety, and operational longevity of the next generation of electrified equipment.

If you are looking for a polymer bearing solution for electricfied equipment, the experts at Advanced EMC are waiting to assist in every step from material selection to the final design and after. Contact us today!

by Sara McCaslin, PhD Sara McCaslin, PhD No Comments

Polymer Seals for Electrified Systems: Managing Heat, Voltage, and Friction

Designing Polymer Seals for Electrified Systems: Managing Heat, Voltage, and Friction

The ability do design polymer seals for electrified systems is vital in modern engineering. The current shift toward electrified systems, whether in EV drivetrains, aerospace actuators, or high-voltage power converters, means that engineers must transform how they think about sealing. Traditional seal design focused on pressure and fluid compatibility. Electrified systems however, add three new variables: electrical conductivity, insulation integrity, and heat dissipation.

The wrong choice of polymer can lead to arcing, insulation breakdown, or premature wear, while the right one can enhance reliability and extend component life. This blog post is going to explore how seal designers can manage heat, voltage, and friction for electrified systems.

Polymer Seals for Electrified Systems

Electrified systems subject seals to hybrid stresses: electrical, thermal, and mechanical. Thermal gradients develop near conductive components, especially in high-current zones or power-dense assemblies. Electrostatic fields and stray currents can compromise material integrity, accelerating degradation. Mechanical wear and vibration persist just as they do in traditional systems—but the allowable frictional losses are often much lower.

Different applications bring unique sealing demands. In electric traction motors, for example, shaft seals must prevent the ingress of coolant while also blocking stray currents. DC/DC converters, meanwhile, are in need of seals that double as dielectric barriers.

Balancing Dielectric and Thermal Properties for Polymer Seals for Electrified Systems

Polymers in electrified systems must play a dual role: insulate against high voltage while managing heat generated in compact assemblies. They key properties involved in designing polymer seals for electrified systems include dielectric strength, thermal conductivity, and wear rate, all of which determine seal performance and longevity.

Common polymer choices include:

  • PTFE is chemically inert, possess excellent dielectric strength, and exhibits ultra-low friction, making it ideal for high-speed, low-load applications.
  • PEEK has high mechanical strength and temperature capabilities, meaning it can tolerate heavier loads but at the cost of slightly higher friction.
  • PPS and UHMW-PE are cost-effective options that combine good dielectric resistance with moderate wear performance.
  • Filled compounds (carbon, graphite, glass) are used to enhance wear and sometimes conductivity, though they may reduce dielectric performance.

Creep resistance, thermal aging, and the ability to maintain integrity across temperature extremes all influence selection. In many cases, designers use blended materials or layered seal architectures to balance insulation with heat dissipation.

Managing Heat

Electrified systems are going to generate localized hotspots located near bearings, windings, and current-carrying seals. Without appropriate heat management, polymers can easily soften, creep, or degrade. Effective seal deisgn for electrified system design requires careful consideration of factors such as thermal pathways, geometry, and material stability.

Thin cross-sections, for example, help to minimize thermal buildup ,but must still resist extrusion issues. Conductive fillers or metal housings can help spread heat away from the seal interface. Engineers must also account for the glass transition temperature of materials, their continuous-use temperature, and their oxidation resistance.

Heat cycling has a major influence on seal preload and spring energizers. In EV cooling pumps, for example, repeated swings from –40°C to 150°C demand highly resilient fluoropolymers and careful thermal expansion matching between the seal and shaft.

Managing Voltage

Seals can be damaged by electrical stress over time. Potential issues include dielectric breakdown, corona discharge, and surface tracking can —  all of which lead to performance loss or catastrophic failure.

Engineers can mitigate these issues through material and design strategies such as:

  • Choosing polymers with a high dielectric strength (PTFE, PEEK, PPS)
  • Using conductive fillers to safely dissipate charge buildup.
  • Designing surface contours and creep distances that reduce the risk of arcing 
  • Grounding components to divert stray currents away from sealing interfaces

Managing Friction

Friction directly affects energy efficiency, thermal load, and component life. In electrified systems, even a small amount of frictional increase can have a significant impact on range of performance. 

Designers must strike a careful balance between low friction and effective sealing contact. Surface finish, lubrication strategy, and seal geometry all play a part, and spring-energized PTFE seals are often chosen for their low-leak, low-drag characteristics.

Because many electrified systems operate in dry or low-lubrication conditions, polymers with intrinsic lubricity or dry-film coatings are critical. Comparing dry-film lubricants, filled PTFE blends, and hybrid polymer systems helps determine which approach provides the best combination of sealing and efficiency.

System-Level Integration—The Interplay of Heat, Voltage, and Friction

Heat, voltage, and friction are not independent. Heat increases friction and reduces dielectric strength. High voltage accelerates wear through localized arcing. Frictional heating compounds both mechanical and electrical stress.

System-level analysis is, therefore, essential for engineers designing a successful polymer seal for electrified systems. Finite element analysis (FEA) can be used to model thermal and mechanical stresses, while electrical field modeling predicts voltage gradients across seal interfaces. 

By co-designing seals with their housings and integrating thermal barriers or conductive paths, engineers can significantly improve both the electrical safety and mechanical durability of seals for electrified systems.

Conclusion: Engineering Reliability in the Electrified Era

Electrification means that no longer is seal design just about blocking fluids or retaining pressure. These seals must manage a delicate balance between heat, voltage, and friction.

When properly designed, polymer seals do not just survive these stresses. They enable higher efficiency, longer service life, better range, and greater system reliability. In the electrified era, seal design is an exercise in electrical and mechanical synergy.

At Advanced EMC, our team of experts can help you find the right solution when designing polymer seals for electrified system. Contact us today to learn more.