Home » Automotive Assembly: Electric Components Open New Doors for Suppliers
Automakers and suppliers are scrambling to produce key electromechanical components, such as axles, controllers, steering sytems and climate-control systems.
To meet growing demand for EVs, engineers are developing a new generation of products. There’s a big need for smaller, lighter, more robust and less expensive components that can meet the demanding high-temperature requirement of in-vehicle applications.
“The objective is to reduce the weight and installation space of these components and increase their efficiency . . . to achieve as great a range as possible on the basis of the battery capacity available,” says Matthias Kusell, who heads up engineering projects for EV and hybrid systems at Bosch. With some creative packaging, Bosch engineers recently created a power electronic module that is 33 percent smaller than previous units. It will be used in 2011 Porsche and Volkswagen hybrids.
With its new generation of power electronics, Continental has reduced the size of its electric motors by 30 percent. “This has been achieved by making components smaller, using new manufacturing and production processes, and by an overall improvement in efficiency,” claims Grotendorst.
In addition to motors and drivetrains, EVs also require a wide variety of on-board charging systems and external charging systems. Several Tier 1 suppliers, such as Delphi and Lear, have jumped at the opportunity to manufacture these systems. More than 50 percent of the patents that Lear, a traditional manufacturer of seats and interior components, filed in 2009 were for EV-related technology.
Cooling systems are another important component that engineers must rethink. Thermal control is a key factor in extending the range of EVs, because batteries, motors, DC-DC converters and other components need stable temperatures to work efficiently.
For example, the Tesla Roadster uses a heat transfer system developed by Dana, a traditional supplier of driveshafts. It cools the vehicle’s battery by transferring heat generated within the battery to the vehicle’s climate-control system. A temperature sensor mount provides continuous feedback to the climate-control system. Dana engineers constructed the heat exchanger using a patented aluminum brazing process.
“The interface helps maintain the battery’s ideal temperature during operation,” says Ted Zielinski, director of engineering at Dana Thermal Products Group. “The use of high-strength aluminum provides greater material strength and contributes to weight savings. Additionally, the chiller’s compact design provides significant space savings-critical for helping engineers accommodate the Roadster’s 6,800-cell battery pack.”
But, the best battery in the world is useless if it can’t communicate to motors, brakes, steering and other critical vehicle systems. “The power electronics devices that sit between the batteries and drive motors are the most vital component of an EV or hybrid vehicle,” claims Carl Bonfiglio, senior segment marketing manager at Infineon Technologies North America. “These components typically include a power module, gate drivers and a microcontroller.
The inverter, which takes DC battery energy and converts it to AC to drive an electric motor (and the reverse in regenerative systems) is the principal system for EV power electronics. Bonfiglio says automakers aim for the highest possible efficiency in the inverter stage. “Up to half of the value of a typical inverter is attributed to the power module,” he points out.
“The power module comprises IGBTs (insulated gate bipolar transistors), diodes, connectors and packaging technology that protects the electronics and provides for cooling,” adds Bonfiglio. “Packaging is critical, as operating temperatures readily surpass 125 C. Higher performing modules now in development will operate at temperatures up to 200 C.
“Reaching the next level of operating temperature will require copper wire bonds between the IGBTs and the module package,” warns Bonfiglio. “To bond to copper, the IGBT itself requires a copper bond pad surface.”
Earlier this year, Infineon unveiled new interconnection technology that’s suitable for high-volume production. It involves bond wiring on the chip front side, soldering on the chip back side and direct copper bond to base plate soldering. A
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