Hello, I am Paul Kane, the Americas leader for DuPont engineering plastics development activities in vehicle electrification systems.

Transcription

1 DuPont Automotive Performance Materials to Help Electrify Vehicles DuPont Automotive Webcast hosted by SAE International Oct. 21, 2009 Hitoshi Shioya DuPont Automotive Global Electrical & Electronic Applications Segment Leader Paul Kane DuPont Automotive Global Electrical & Electronic Senior Development Programs Manager Hello, I am Paul Kane, the Americas leader for DuPont engineering plastics development activities in vehicle electrification systems. And I am Hitoshi Shioya, the global segment leader for polymers used to make vehicle electrification possible and more efficient. While electrification affects all vehicle systems, Paul and I will concentrate on the opportunities for mass and cost reduction for advance propulsion systems. (slide 2) Let s start with a market forecast for hybrid and plug-in electric vehicles by HiEdge, a major data gathering and reporting organization. As we all know, Toyota has the lead in the production of hybrid electrics. But this chart indicates that virtually all major automakers will be launching electric vehicle programs. In just over 10 years, vehicle sales are projected to be well over 9 million units -- more than 10% of total new vehicle production. To make this a reality, the cost and weight of major electric propulsion systems must come down. (slide 3) Here are some of material requirements to reach the mass and cost targets for next generation electric vehicles. Overall, new materials and integrated component designs are required to reduce mass by 30% - 40% from the extra 200 kilograms or so that electric propulsion systems add to vehicle weight. Managing temperature is key to performance and safety. Electric traction motors can see temperatures as high as 170 C. The battery must not overheat and yet deliver power at outside temperatures as low as -40 C. Contact: Dial DuPont First

2 Higher voltages are required for better efficiency. So materials must offer better dielectric properties and greater volume resistivity. There is also research to develop hybrid metal-plastic material solutions that can offer EMI shielding for sensitive electronics. To keep all systems within their temperature operating range, materials in thermal management systems will need chemical resistance to coolants and automatic transmission fluid. New solutions will also be needed for components that can both insulate and be thermally conductive. (slide 4) Here are the systems we are addressing: Battery packs that are moving from nickel metal hydride to prismatic lithium-ion cells. Electric traction motors that are increasing in rpm and voltage. Power electronics that are generating more heat in already crowded engine compartments. Higher voltages, up to 650 Volts, that demand better polymers for connectors. Thermal management systems to cool and heat, as needed. (slide 5) Shown here are the three key existing systems used on the Toyota Prius. The inverter or power control unit, battery pack and electric traction motor. Toyota has already developed its third generation power control unit that has more integrated parts, offers a 650-volt power boost and simplifies the cooling system for lower weight, size and efficiency. The battery is perhaps the most expensive system as more auto makers move to lithium ion technology. Packaging the battery for less space, reducing weight and managing temperature to around 40 C with a cold temperature start-up capability are major challenges. The electric motor, connected to the drive shaft, or soon to be located at the wheels, must have better magnet wire insulating materials in the stator and improved magnet encapsulation in the rotor to avoid power losses. Let me turn it over to Paul Kane for a closer look at how better materials are already offering better solutions. Contact: Dial DuPont First

3 (slide 6) You will understand that we cannot talk about specific next generation electric vehicle parts in research and development stages. But we can talk about materials developments that have already commercialized along with some of our goals. The Power Control Unit or Inverter is the power management brain, using insulated bipolar gate transistors that act as switches to convert DC to AC and to step up voltage. Particular challenges for the IGBTs is electrical isolation and cooling. Today, high temperature PPA, in the form of our Zytel HTN, is used to handle 600-plus volts in the power cable connectors from the battery to the inverter to the electric motor. The cable itself is made from engineering thermoplastic vulcanizate called DuPont ETPV, and/or Hytrel thermoplastic polyester. Both materials offer great flexibility with high temperature and chemical resistance. In future Power Control Units, we envision integrated housings, inverter lead frame over-molding techniques and assembly methods such as laser welding for cooling channels using our new electrically friendly PPA materials that I will talk more about later. This will permit even more parts integration for greater space and cost savings. We also have special flame retardant V-zero UL rated PPAs for these applications. (slide 7) Future Li-ion battery systems will be either liquid cooled or air cooled. For liquid cooling and, I might add heating, polymers compatible with long life coolant, dimensional stability and low stress relaxation properties under stress are needed. Our Zytel HTN PPA can offer 1/3 lower moisture absorption rate versus glass reinforced nylon 66 and excellent long life coolant resistance and superior mechanical properties with coolant and humidity exposure. Other efforts in DuPont are aimed at improved cell separators using a high temperature, micro fiber nonwoven material that offers better barrier properties and lower ionic resistance. Still more R&D efforts are aimed at new chemistries for safer electrolytes and improved electrodes and binder systems. (slide 8) Often, automatic transmission fluid is used to cool the motors that can generate temperature peaks of 170 C. Power connectors in hydrolysis resistant, heat stabilized grades of our Zytel HTN are common for electric motors. Tests show that PPAs offer excellent resistance to long term ATF exposure at high temperatures along with the best combination of electrical properties. Contact: Dial DuPont First

4 Materials are being developed to optimize encapsulation of the ferrite or NeFeB motor magnets themselves for superior heat-aging performance and as a moisture permeation barrier. If the magnet wire insulation is compromised, motor efficiency will drop off rapidly. That s why DuPont offers inverter service, corona resistant enamels and varnishes or new, thin wrapping tapes in high temperature Kapton polyimide film. New versions of Nomex aramid paper insulation are underway. (slide 9) Here is a motor schematic we use to show where various DuPont materials can be used from resins such as Crastin hydrolysis resistant PBTs, to Teflon, to Zytel HTN. Coatings such as Voltron and Voltatex for magnet wires, Kapton and PEN films and Nomex aramid paper for slot liner insulation, Vespel precision parts for bearing surfaces and even Krytox fluorinated lubricant for motor shafts and bearings. Let me now turn it back to Hitoshi who will explain what we mean by electrically friendly resins. (slide 10) Electrically friendly PPA resins have been commercialized on the three-phase connector systems between the power control unit and the electric motors and generators. The development of these electrically friendly resins has been recent. Their development is due in part to our work on hybrid electric vehicle systems in Japan and elsewhere. We re now launching them for trial and commercial use. By saying, electrically friendly, we mean materials that combat the ionic corrosion of copper wires and terminal leads. They also offer excellent electrical isolation, very high comparative tracking resistance of over 600 volts along with a very good balance of mechanical properties for component integrity. (slide 11) Here are three 35% glass reinforced grades that we are launching. All are semi aromatic polyamides that are referred to generally as PPAs. The first, HTN 51G35 EF, offers excellent chemical resistance with the highest service temperature resistance. With a TG of 140 C, it retains its high tensile modulus in moist environments at temperature versus products such as nylon 66. The second, HTN 52G35 EF, offers higher flow for thin wall parts and can be molded using water controlled mold temperatures. Contact: Dial DuPont First

5 The third, HTN 54G35 EF, offers some added toughness for thermal cycle resistance and also can be molded at lower temperatures with water controlled molds. (slide 12) This spider chart shows how performance of the HTN 51G35EF resin compares with the other most commonly used material, PPS, At a glance, you can see how the red profile of the HTN compares to the dotted blue profile for PPS. In left side chart, our HTN EF had improved volume resistance from HTN standard grade. Also in right side chart, HTN EF provided CTI and mold ability advantage versus PPS. For more detail, Paul will quickly run through some results of our testing in the following few charts. (slide 13) You see three circled areas that point out some key performance advantages of the EF electric/electronic friendly - resins compared to PPS. Higher glass transition temperature indicating superior high-temperature stiffness, volume resistivity at 150 C indicating very good electrical insulation properties and a extremely high comparative tracking index that indicates the material will hold up to a 600-plus volt environment. (slide 14) Automotive OEMs are specifying a comparative tracking index of 600-plus volts for critical hybrid-electric components, such as connectors and over-molded lead frames. The CTI-test method is an accelerated test measuring the performance of insulating materials in wet or contaminated conditions. The failure mode is carbon paths or tracks that develop near electrodes. Eventually a series of tracks span the electrode gap and there is an arc that shorts-out one or both of the electrodes. (slide 15) Let me wind this up with some comments about the performance of these PPA materials in thermal management systems for electric vehicle systems. There is a big challenge to integrate existing HVAC and Powertrain cooling systems with electric vehicle power systems thermal management. If you looked at these systems separately, there could be five independent cooling circuits with added pumps, thermostats, surge tanks hose and tubing and electronic controls. The goal is to integrate as much as possible into perhaps one or two complex manifolds that can manage the systems together. That could be the subject of another webinar, but let me position our product offering against the basic needs. Contact: Dial DuPont First

6 (slide 16) In long term testing, PPAs retain their stiffness better than glass-reinforced nylon at temperature when exposed to aggressive long life coolant. You can see how the delta increases over time. Zytel HTN retains 95% of its stiffness at 500 hours and is better in coolant than PPS. (slide 17) Here is a stress at break comparison of PPA with PPS of up to 2000 hours at 130 C. (slide 18) And from a base glass-reinforced polymer standpoint, here is a comparison of strength, elongation, tensile modulus and specific gravity of PPA versus PPS. All these properties show a significant edge for our reinforced Zytel HTN products. (slide 19) Here is another look at how our 35% glass reinforced HTN retains its strength and stiffness at temperatures for power electronic parts exposed to high temperatures. PPA maintains its performance better out to 180 C. And remember, you will be able to obtain more detail on these subjects by visiting automotive.dupont.com. Now let me turn it back to Hitoshi to close out this segment (slide 20) We thank you for your time with us and we look forward to your questions and comments later on. In summary, we have established a good position, especially with our PPA materials in virtually all hybrid electric and electric vehicle systems. But as you heard, we are working hard to develop even better materials and we are conducting considerable R&D in and beyond our thermoplastic resin offering. We hope this session has given you ideas of how we may collaborate on your future programs and projects. (slide 21) Now, let s go to our last segment managing friction and wear using new technology for Vespel parts. Dave leads the global transportation for Vespel parts and shapes and will share insights into how to design out friction. # # # Because we cannot anticipate or control the many different conditions under which this information and/or products may be used, neither DuPont nor the authors guarantee the applicability or the accuracy of this information or the suitability of its products in any given situation. Users of DuPont products should make their own tests to determine the suitability of each product for their particular purposes. The data listed herein falls within the normal range of product properties but they should not be used to establish specification limits or used alone as the basis of design. Disclosure of this information is not a license to operate or recommendation to infringe a patent of DuPont or others. Contact: Dial DuPont First

7 Copyright 2009 E.I. du Pont de Nemours and Company. The DuPont Oval Logo, DuPont, The miracles of science, and all products mentioned in this document are registered trademarks or trademarks of E.I. du Pont de Nemours and Company or its affiliates. All rights reserved. Contact: Dial DuPont First