E-motor potting, utilizing thermally conductive materials, offers an efficient solution for protecting and dissipating heat in EV drive systems. This method not only safeguards electronic parts from environmental stressors but also improves overall heat transfer, ensuring your EVs run smoother and last longer. This blog will provide valuable insights into optimizing EV motor performance. We will dive into why thermal management is essential for EV motors, the advantages of using thermally conductive potting materials and explore leading products in the market and future trends in thermal management for EVs.
Why Thermal Management is essential in EVs Motor?
Motor designers have long faced the challenge of managing heat in motor designs. Without proper thermal management, thermal losses can drastically reduce power efficiency, degrade motor performance, and lead to premature component failure. Excess heat not only hampers overall performance but can also cause insulation breakdown, demagnetization, and damage to sensitive electronics, significantly shortening the motor’s lifespan.
As electrification drives the need for motors with higher voltages and power densities, effective thermal management becomes crucial. Proper thermal management minimizes power losses (I²R losses), enhances performance, and ensures reliability and efficiency.
Related article: Why thermal management is necessary?
Benefits of Using Thermally Conductive E-motor Potting
Historically, varnishing rotor and stator windings was a common practice for basic insulation. However, these solvent-based varnishes, which contained high levels of Volatile Organic Compounds (VOCs), have been restricted due to environmental concerns. Additionally, they do not meet the higher demands of modern high-voltage e-motors, which require greater power density, reliability, and endurance.
This has led to a shift towards thermally conductive potting materials, offering several key advantages:
- All-Round Protection: Potting materials create a robust barrier against environmental factors such as moisture, dust, and chemicals, ensuring motor components remain functional and reliable in harsh conditions.
- Electrical Insulation: Potting fills internal voids within the motor, preventing air pockets that could lead to partial discharges, and ensuring optimal electrical insulation critical for safe high-voltage operation.
- Thermal Dissipation: High thermal conductivity potting materials efficiently transfer heat away from critical components, preventing overheating and maintaining motor performance while extending its lifespan.
- Noise, Vibration, and Harshness (NVH) Reduction: Potting materials help dampen vibrations and reduce noise levels, contributing to a quieter and smoother operation of EV motors, which enhances the overall driving experience.
The Prevalence and Benefits of Epoxy Resin in E-motor potting
Epoxy resin is the preferred potting material for high-voltage EV motors, especially where high performance and high glass transition temperature (Tg) are crucial. Epoxy resin could offer:
- High Glass Transition Temperature: Epoxy resins maintain stability under elevated temperatures, essential for the demanding conditions of EV motors.
- Mechanical Strength: These resins offer excellent mechanical properties, protecting motor components from stress, vibration, and thermal cycling.
- Chemical Resistance: Epoxy resins resist chemicals found in electric and hybrid vehicles, including cooling fluids and oils, ensuring long-term reliability.
These properties make epoxy resins ideal for high-voltage electric motors, balancing performance, protection, and durability. Common product for e-motor potting can be considered:
ARALDITE® CW 30386 /ARADUR® HW 30387 for Rotor coil potting
- Tg of 200°C well above Tmax_operation, TC= 0.6W/mK
- High strength and modulus supporting the rotor structure during operation within the entire operation range of -40°C to +180°C
- Low density reducing weight and inertia of the rotor
- Excellent flow and high reactivity help to reduce cycle times
- Low CTE matching surrounding metals and like this reducing thermally induced stress
CW30334/HW30335 for stator potting
- High thermal conductivity 1.2 W/mK
- Excellent thermal shock crack resistance
- High thermal endurance index
Elan Cast E88 Resin/ C89 Hardener
- Working temperature up to 1800C
- High thermal conductivity 0.95 W/mK
- UL94 V-0 listed
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Beside the materials used in potting, for more information on the potting system, you can refer to the articles:
- Automated Potting and Encapsulating System
- Essential guide to Potting and Encapsulating Materials and Equipments
Future developing trend of requirements for EVs
As the demand for EVs grows, so do expectations for improved range, faster charging times, and expanded charging infrastructure. New designs often feature smaller components with higher power outputs, leading to increased heat generation. This trend drives the need for advanced resins with superior thermal performance to meet evolving demands.
At Prostech, we are dedicated to supporting customers with expert product selection to ensure the best fit for their high-voltage electric motor applications. Our focus is on providing solutions that enhance thermal management and motor performance. As the e-mobility market continues to evolve, effective heat management remains crucial. Our team is ready to assist design engineers in choosing the optimal encapsulation resin for their specific needs, ensuring reliable and efficient performance in next-generation EV motors. Please contact us by leaving your contact information below:
