Hybrid and electric vehicles have high-performance motors. What kind of electrical insulation challenges will design engineers encounter?

Hybrid and electric vehicles depend on high-performance motors, inverters, and batteries that bring a new set of challenges to design engineers. What electrical insulation, thermal management, and EMC/EMI shielding materials are required?

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  • Craig McClenachan

    Craig McClenachan

    Vice President Fabrication and Assembly Business Unit FABRICO To read Craig's opening, click here
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    1. Hybrid and electric vehicles are going through a tremendous growth spurt. Their appeal is understandable: better gas mileage, greener operation, and less dependence on fossil fuels. The motors in HEVs and EVs are different from gas-powered engines. They use high voltage batteries to drive powerful, high operating temperature motors that are more compact and include more electronics. Static voltages can be 36V to 330V with operational voltages to 660V. Selecting the right electrical insulation materials that meet the application, whether Class F or Class H, is key. In addition, the operating temperatures of these motors might be as high as 180 degrees C. Selecting thermal management materials is also a critical task. An experienced materials supplier and converter can help you to investigate and test materials before sourcing to ensure they will meet requirements.

  • Roger Wicks

    Roger Wicks

    Global Technical Marketing Manager Electrical Insulation Solutions DuPont To read Roger's opening, click here
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    1. There are a number of electrical and thermal challenges facing HEV and EV design engineers. Solving them requires working with a partner, like DuPont, who has not only a broad range of materials, but also a good understanding of polymer science and extensive materials testing capabilities. It will be important to work with materials like Nomex® brand insulating papers, Kapton® polyimide films, and Voltatex® liquid dielectrics to develop the complete system of materials that these motors require to handle electrical insulation and thermal performance. As voltage increases and temperature rises, complete testing of materials is required to be certain that will not breakdown during operation. Existing and new materials are being developed to handle the increased needs of HEV and EV motors, inverters, and batteries.

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10 Responses Below

  1. Can you offer some examples of how a Nomex and a PPS lamination, or Nomex and PET or PEN lamination might be used for electrical insulation in an EV or HEV?

    by DSeyler on December 15, 2011 at: 8:58 am
    • Designers must face decisions regarding the thermal, mechanical, and electrical requirements of an insulation material or system in many areas of an EV/HEV design. In many cases, a single material may not be the solution, but a combination. This could be a fabricated part where multiple materials are combined, or a flexible laminate. Flexible laminates have been used that combine Nomex paper with a wide range of films, typically based on either the thermal or chemical requirements of the end use application. DuPont can help engineers understand the options in the decision process.

      by Roger Wicks on December 15, 2011 at: 9:03 am
  2. In addition to vibration, what other kinds of stresses should you test for in motor applications?

    by Sam on December 15, 2011 at: 8:45 am
    • Motors for EV and HEV applications are subjected to different stresses than motors used for industrial applications. Vibrational levels are higher, the chemical threats are different, and the inverters can cause issues with the insulation system. DuPont has worked with motor manufacturers to develop test programs to evaluate motor insulation systems in ways different from standard tests so that the system test more closely models the stresses the motor will see in an EV or HEV application.

      by Roger Wicks on December 15, 2011 at: 8:49 am
  3. Is it important to test for chemical compatibility related to ATF fluids?

    by GBuser on December 15, 2011 at: 8:38 am
    • Yes. ATF fluid is used as an internal coolant in some HEV motor designs, and yet the primary means of testing chemical compatibility, sealed tube testing, yields very poor results. DuPont has developed a new dual-temperature test to allow a correct thermal evaluation of materials being cooled by ATF fluids.

      by Roger Wicks on December 15, 2011 at: 8:42 am
  4. What types of thermal management materials are used in battery applications?

    by A. Sehic on December 2, 2011 at: 9:42 am
    • We see a lot of different materials used for thermal management in battery applications including phase change materials, insulating pads, and gap filers. In one specific HEV application we have used a silicone sponge material to increase the contact area for heat dissipation between a battery cell and a cooling bar.

      by Craig McClenachan on December 2, 2011 at: 9:44 am
  5. Why are corona resistant materials used in HEV and EV motors?

    by Steve on December 2, 2011 at: 8:36 am
    • The higher voltages and frequencies seen in the motors for EVs and HEVs can contribute to initiation of partial discharge in the motors. Corona resistant materials are typically the answer to these problems. DuPont can uniquely provide corona resistant solutions no matter the design of the motors. Smaller, random wound motors use enamel coated wires, and larger form wound motors use film wrapped wires, so a variety of corona resistant solutions are required. DuPont has additionally developed unique testing capabilities to test the actual wires used in the motor process.

      by Roger Wicks on December 2, 2011 at: 8:40 am