A Step-by-Step Guide to Adding Insulation Materials to Automotive Systems

Automotive drive systems are becoming more compact, powerful, and electrically demanding, especially when electric vehicles continue to develop. These changes place greater pressure on materials that protect windings, conductors, magnets, and other components from heat, electrical stress, mechanical movement, and chemical exposure. We at Sui On Insulating approach automotive insulation as part of the complete drive-system design, helping engineers match materials to specific operating conditions and reliability requirements.

Step 1: Define the Insulation Requirements

The first step is to understand exactly what the insulation must protect and which stresses it will experience. Automotive drive systems can encounter high temperatures, vibration, electrical voltage, mechanical abrasion, moisture, and exposure to automotive fluids. EV systems can also introduce higher voltage and faster switching conditions.

We recommend identifying the voltage level, temperature range, mechanical loads, available installation space, and expected service life before selecting a material. This prevents engineers from choosing insulation based only on one characteristic, such as dielectric strength, without considering the complete operating environment.

For high-voltage EV systems, partial discharge resistance can also become an important consideration. A material that performs well under conventional electrical conditions may require additional evaluation when used in advanced high-voltage motor architectures.

Step 2: Identify the Components That Need Protection

Once requirements are established, we map the insulation requirements to individual drive-system components. Electric motors commonly require insulation around windings and conductors, while other components may need protection from heat, mechanical movement, or electrical contact.

Different locations may require different material constructions. Thin films can be useful where space is limited, while stronger papers or composite materials may be preferable where mechanical protection is required. This component-by-component approach allows us to avoid using a single insulation material throughout a system when different areas actually face different stresses.

For automotive manufacturers, this can also support more efficient material utilization. The objective is not simply to maximize insulation thickness, but to provide sufficient protection while respecting the dimensional and manufacturing constraints of the motor.

Step 3: Select Materials According to Operating Conditions

Material selection is the core of automotive insulation design. Arclin (formerly DuPont) Nomex® aramid paper, for example, can provide thermal and mechanical protection in demanding electrical applications. Polyimide films offer another option where engineers require a thin insulation material with strong thermal and electrical performance.

We at Sui On Insulating also provide SOFLEX® NSN composite paper for applications requiring a combination of insulation and mechanical characteristics. For newer high-voltage architectures, PEEK materials can be considered where partial discharge resistance and compatibility with automatic transmission fluid (ATF) are important requirements.

Our broad product range allows us to approach insulation selection according to the actual application rather than forcing every automotive drive system into the same material solution.

Step 4: Consider High-Voltage Requirements

The transition toward higher-voltage EV platforms makes electrical insulation increasingly important. Moving from lower-voltage architectures toward systems such as 800V can help manufacturers pursue higher power and charging performance, but it also creates additional electrical insulation challenges.

High-voltage insulation needs to maintain its protective function under the electrical stresses generated during operation. Partial discharge is particularly relevant because repeated localized electrical activity can contribute to insulation degradation over time.

We therefore consider partial discharge resistance when developing insulation solutions for 800V automotive drive systems. Our PEEK materials are positioned for applications requiring 800V high-voltage partial discharge resistance, providing an option for engineers working on next-generation EV motor technologies.

Step 5: Evaluate Heat and Mechanical Stress Together

Temperature is rarely the only concern inside an automotive motor. Insulation may simultaneously experience thermal cycling, vibration, movement, friction, and pressure from surrounding components. Selecting a material solely according to its temperature rating may therefore overlook important mechanical requirements.

We evaluate materials according to the combination of stresses they may encounter. Nomex® aramid paper and polyimide films can provide thermal and mechanical protection, while composite constructions can address applications requiring a different balance of properties.

This combined approach is especially useful for compact motors, where components are positioned close together and available space is limited. Insulation must protect the electrical system without unnecessarily increasing the size or complexity of the assembly.

Step 6: Check Chemical Compatibility

Chemical exposure is another requirement that automotive engineers should establish early in the design process. Insulation inside a drive system may come into contact with lubricants, coolants, or other fluids depending on the motor architecture and application.

Compatibility should therefore be evaluated under realistic operating conditions rather than assumed from general material descriptions. We pay particular attention to applications where insulation may be exposed to automatic transmission fluid.

Our PEEK materials are designed to address applications requiring ATF chemical compatibility, making them relevant when engineers are developing insulation systems for modern automotive drive systems with demanding fluid environments.

Step 7: Validate the Complete Insulation System

Selecting individual materials is only part of the process. Engineers should validate the complete insulation system under representative electrical, thermal, mechanical, and chemical conditions. Manufacturing processes should also be considered because cutting, forming, winding, bonding, and assembly can influence final performance.

We work with automotive customers to connect material selection with practical application requirements. This helps us identify potential gaps early and develop new solutions when existing materials do not fully satisfy a particular motor design.

Moving Automotive Insulation from Material Selection to System Reliability

Effective insulation for automotive drive systems requires a structured process: define operating conditions, identify protection points, select suitable materials, evaluate high-voltage behavior, assess thermal and mechanical stresses, check chemical compatibility, and validate the finished system.

We at Sui On Insulating support this process with a complete range of automotive insulation solutions, including Nomex® aramid paper, polyimide films, SOFLEX® NSN composite paper, and PEEK materials. By combining broad product coverage with rapid new-solution development, we help automotive manufacturers address changing EV motor requirements and integrate insulation more effectively into next-generation drive systems.