From Emissions Tech to EV Electronics
Eberspaecher’s Electronics unit is enabling big growth in EV and AV business.
A recent visit to Eberspaecher’s North American engineering and manufacturing complex reveals how a global Tier-1 rooted in combustion-engine technology is profitably navigating the transition to the electrified future.
In the Brighton, Michigan, plant, which produces 40% of U.S. Class-8 diesel exhaust systems, catalyst bricks are being canned and prepared for shipment to OEMs. Meantime in the facility’s engineering offices, work is progressing on next-generation heating systems for passenger and commercial EVs, power electronics, automated-driving systems, and high-voltage switching solutions. Best known for 90 years as an exhaust-systems and climate-controls supplier, the Germany-based company is now a parallel force in electric power switching and distribution. Since establishing its Electronics business unit in the early 2000s, Eberspaecher has produced 30 million electronic control modules, more than 17 million high-performance switches and six million DC/DC converters, among other power-net components.
“We are in development with a customer right now on an SAE Level 5 fully-autonomous vehicle that will launch within a year,” reported Joe Vollmer, the veteran engineer who heads North American business for Eberspaecher’s Automotive Controls and Climate Controls divisions. For the past five years his team has been busy with multiple AV projects. “A particular Detroit-3 automaker needed to have its AV programs moved forward and urgently needed a supplier to step up to ‘move the electrons’ to the critical devices, under the ASIL-D regimen. And we were chosen,” Vollmer noted.
ASIL-D is among the most stringent Automotive Safety Integrity Levels, a risk classification system defined by the ISO 26262 standard for road vehicle functional safety. Vollmer’s team developed the customer’s first-generation AV power electronics and will soon deliver the second generation, he said.
EV, give me heat!
With its fuel-operated heaters popular in marine applications since the 1950s, Eberspaecher added electric heaters in 1999, beginning as a JV with TDK. The core technology is the PTC (positive temperature coefficient) thermistor. Vollmer and applications engineer Robert Tate see significant growth potential for new EV (and advanced ICE) heating technologies. Both recognize the industry’s need for more efficient HVAC without the range-robbing parasitics of current systems.
“I joined Eberspaecher in 2011 as we were launching on the Chevrolet Volt,” Tate said. “Our first-gen heaters were on most of the first wave of EVs. Many of the early electronic and electrical components used then weren’t automotive-qualified. The only thing then available in the voltage range the OEMs were moving to were 1,000-volt IGBTs made for fighter aircraft! Today’s MOSFETs are on the move and are better for reverse-polarity. We had to do a lot of R&D work in high-voltage switching to make it happen.”
Tate noted some OEMs’ interest in geothermic heat pumps as an EV cabin heat solution. “But [heat pumps] aren’t terribly efficient in cold temperatures,” he explained. “That’s where Eberspaecher fits; we specifically use PTC heating elements that perform best in cold temperatures. As the element gets hotter, it acts as a variable resistor letting less electricity through. In PTCs, the heating element will never raise above a certain temperature; that dramatically reduces any risk of fire.” Originally Eberspaecher purchased PTCs on the market, then invested in its supplier Rauschert and in 2016 took over its PTC development and production.
The challenge with EV cabin heat is “balancing heat when it’s needed with vehicle range, which is directly related to battery capacity and size. That’s the bottleneck in EV development,” Tate asserted. “You don’t want to consume more energy than is necessary but need to keep comfort and safety in mind. In California, for example, you might be able to get away with a 2kW-3kW heater. But automotive designs for the 100-percent use case, not 20 or 50 percent.” Roughly 10% of an EV battery is scaled for cabin heat and cooling.
Tate’s team sees various EV heater strategies emerging. Some OEMs are focusing on larger heaters they plan to run for shorter periods, with the goal of maintaining temperature in the coolant and in the cabin. Others are adopting a “localized approach” including electric seat heaters incorporating blowers that vector warm air on the occupant’s neck. “They’re called a ‘neck scarf’ and we’re involved with that technology,” he said. “It’s very popular in Europe on convertibles.” Another more costly strategy is decentralized heating that fits mini heaters in the vents, closer to the seats, to warm up the customers more efficiently.
Eberspaecher’s latest heater is designed to be located on the coolant loop. According to Tate, engineers debate whether a coolant loop heater is the right choice for an EV versus an air heater, the output of which feels more direct. “One thing that gets overlooked is these systems are putting out 5kW to 8kW of heat – that’s equivalent to house heating,” he noted. “That may be a bit overpowering, but it’s necessary to warm the occupants and clear the windshield.”
The company’s fourth-generation heater technology is entering production. Its design boasts a reduced number of heating elements. “We’re generating more heat performance with fewer components,” Tate explained. “In relation to the battery it’s not that impressive, but in terms of design cost and overall size, we’ve made year-over-year improvements.”
Latency and liquid cooling
Looking ahead in electronics technology to meet industry trends, Vollmer and Tate note the move to higher system voltage levels. “There’s a lot of talk about 800 volts, and we have definite development plans in that realm,” Vollmer said. He added that OEM development cycles “are wild right now — faster, with changing component requirements — because of all the improvements that are coming.” The automakers also are “learning quickly about high-voltage component requirements and how they need to interact with one another. This has led to communication-network changes, from CAN to LIN, for mixed-signal vehicles. We’ve had to be quick at adapting to the different vehicle networks,” he explained.
In the automated-driving space, in-vehicle data processing speed with decreasing latency is another challenge. “The AV world is going after 100-microsecond latency,” Vollmer said. “The first question the vehicle topology people ask us is, ‘How fast can we switch?’ That determines how to build up the hardware set. Does it need to be an ASIL-D microprocessor? All the components we select must be able to meet the specified switching times.” There are also discussions on cooling strategies. Liquid cooling is a current topic with Eberspaecher’s commercial vehicle customers, he noted.