Airing on the Side of Innovation

Lucid Motors’ home-grown technologies are setting the pace in electrification. Top engineers tell how and why they’re building a benchmark.

Even as pricing for raw materials rise, Lucid aims to use its home-grown technologies to drive down EV cost. (Lucid Motors)

Is there a proven formula for creating a top-notch engineering organization and benchmark product from scratch? Lucid Motors CEO Peter Rawlinson shared his approach at the company’s Newark, Calif, headquarters. “We have a very small team of brilliant engineers that we’ve managed to attract to the company with a vision: to do the best electric vehicle ever,” he explained. “It will be outstanding for your career; it will be stimulating,” he told them. “And they came.”

Small and mighty: Lucid’s traction motor showing planetary gearset. The differential resides inside the stator center. (Lucid Motors)

Rawlinson, who previously led Model S development at Tesla and was top engineer at Jaguar and Lotus before that, used a similar talent pitch at Tesla. The then-obscure startup had just six engineers when Rawlinson joined in 2009. “Peter is the amalgamating leader at Lucid,” noted Eric Bach, the senior VP of product and chief engineer who left Volkswagen to join the Lucid crusade. He said Rawlinson looks for “raw intellect times hours,” meaning drive and desire. “With raw intellect, it doesn’t matter if the other people on the team are from automotive, aerospace, or elsewhere,” Bach explained. “Because it’s all about engineering fundamentals.”

No question that Lucid’s leadership, including senior engineering director Dr. James Hawkins (ex-Aston Martin), design chief Derek Jenkins (Audi, VW, Mazda), and their colleagues squarely nailed the fundamentals for their first production vehicle, the remarkable 2022 Air. The luxury electric sedan, built at Lucid’s Casa Grande, Arizona, plant, is impressing customers with its industry-leading range (516 miles/830 km per charge), its blend of speed, agility, and mile-eating comfort, and its innovative technologies.

Beyond establishing the Air as an EV pace setter, the team’s mission is “to advance the state of the art in electric cars; to show what’s possible – and to use our technology to drive the price down,” Rawlinson asserted. But like a similar recent announcement from competitor Rivian, Lucid announced on May 5 that it was raising base prices on the Air sedan as much as 13% starting June 1, 2022, to combat rising raw materials costs, stating it would honor all current reservations at their original pricing.

Efficiency as king

Total vehicle efficiency is the team’s mantra, exemplified by the Air Grand Touring model. The GT’s 926-volt, 112-kWh battery pack consists of 6,600, cylindrical 21700-type cells arranged in 22 modules, 300 cells per module. The LG Energy Solution cells nestle in a simple and robust Lucid-designed single-shot, injection molded structure, incorporating a cold plate on its back side. “It’s super cheap to make,” Rawlinson said. “The design can be mass produced by the millions.” Most importantly, the Air delivers a maximum 516 miles/830 km range on the EPA drive cycle, which equates to 4.6 miles per kilowatt-hour.

“There was no single enabler for this efficiency achievement,” Hawkins told SAE Media. “It comes from attention to systems engineering and gaining a percent here and a percent there. They add up.” The next Air model, called the Pure, launches later this year with a smaller, lighter 88-kWh, 18-module pack and 400 miles/644 km range, at a significantly lower price point (currently reserving at $77,400, then $87,400 after June 1) than the limited edition $179,000 launch model.

The team is leveraging a mass-compounding factor by optimizing total systems efficiency, with focus on the powertrain, Hawkins said. Less battery weight means less structure to carry it around, less cost and greater simplicity; every 15 kg (33 lb.) of vehicle mass saved yields about one extra mile of range. But as he and Rawlinson admonish, there is too much emphasis on the battery in many EV discussions. “It’s [the battery] just the gas tank of the EV,” Rawlinson quipped. “The motor and inverter are more important to how we get the range and efficiency – we’ve got a more efficient motor than anyone else. We’ve got a more aerodynamic car.”

Using Rawlinson’s “space concept” vision, the Air was designed from the inside out, creating a car that’s smaller on the outside than a Tesla S but featuring a roomy interior with more rear seat legroom than a long-wheelbase Mercedes S-Class. It’s also agile and, with 1,080 hp (805 kW) available through all four wheels, fun to drive.

The team didn’t aim for king-of-the-hill 0-60 mph acceleration in its target setting. Instead, it aimed for range, efficiency and “mid-range punch.” Deft aerodynamic work by Jenkins’ designers and Lucid aerodynamicist Jean-Charles Monnet, hired from the Red Bull Formula One team, resulted in an aircraft-inspired exterior form boasting a .20 Cd(A). Rawlinson noted Air is slipperier than a Mercedes EQS. Even the underside of the Air’s battery pack is slightly radiused for lower drag, “to achieve better airflow attachment toward the back of the car,” Monnet said. An underbody diffuser is mounted from the B-pillar rearward. But the key to optimizing total vehicle efficiency was minimizing the electric powertrain.

In-house engineering focus

Rawlinson said the Air program’s biggest achievement, and biggest risk, was undertaking the ‘space concept’ without the powertrain technology (at the time) to make it work. “If it [powertrain] couldn’t be miniaturized, the concept wouldn’t fly,” he explained. The first Air prototype was only two-wheel drive because the new, ultra-compact drive module being developed in parallel, in house, wasn’t ready. “I don’t think any other company would be crazy enough to do that,” he said.

The Lucid team are stalwarts of in-house development for bar-raising technologies including exterior lighting, bi-directional charging and the drive module. The latter integrates the power electronics, e- motor and transmission into a beautifully compact, 74-kg (160 lb.) package. Rated at 670 hp (500 kW), the drive module looks tiny compared with the similar hardware from Tesla (Model 3) and GM (Bolt) on display during SAE’s visit.

“You cannot buy the technology that we’ve got,” Rawlinson opined. “If all I wanted to do was another car, I would have done that with suppliers. A whole bunch of [EV] startups and established OEs are just buying stuff. But where is the value of a company that just buys-in its motors, for example? For some items, of course, we’re not going to reinvent the wheel; Bosch does a great i-boost [braking] system. Akebono does great foundation brakes. Pirelli and Michelin do great tires for us.” The company also designs all of its printed circuit assemblies (PCA).

Lucid’s objective to advance the state of the art in EVs “sounds like bullshit, but it’s true,” Rawlinson said. “It’s what is necessary to achieve accelerated widespread adoption.” He noted electrification is a technology race, with the first milestone (500-mile range) achieved. The next milestone is significant cost reduction “so that the man in the street can afford an electric car.” Added Hawkins: “We need to understand the entire system, and every bottleneck within it. If we had somebody else design an inverter for us, there is always some part that we can’t control. And if we can’t control it, we can’t optimize the entire system. With our own technologies we have command over our destiny.”

Unique drive module

The ‘wonderbox’ 19.2-kW bi-directional charger located midship in the Air. Developed in-house by Lucid, the unit enables vehicle charging up to 924V and includes a DC-DC converter for a 400V intermediate bus to power vehicle systems. With DC fast charging, the system can charge the Air at a rate of 300 to 350 kW delivering roughly 20 miles of range for each minute charging. (Lindsay Brooke)

Among the Air’s tech stars, the drive module may shine brightest. It’s a triumph of systems engineering and thorough analysis of electromagnetics, motor topology, power flow and cooling. According to Bach, the geometry and physics that went into the design are what give Lucid’s motor its formidable power density. The drive unit can be used front, rear, or on both axles in the vehicle; only the motor mounts are different. In the Air, the rear drive unit is rotated 90 degrees to make it “flatter” in profile and thus provide more luggage compartment volume.

The electric machine is an oil-cooled permanent magnet design, optimized to reduce internal resistance to free spinning, Bach said. Uniquely, the differential is located inside the rotor, “our secret sauce,” he calls it. Rawlinson describes the arrangement as “a single rotational inertia system” that avoids the tolerance-related losses inherent with many motor-gearbox pairings. The design engineering is most remarkable when viewed in a cutaway display motor at Lucid HQ. Unfortunately, photos were forbidden during our visit. The engineers said they looked forward to teardown specialists Munro & Assoc. fully dissecting an Air and reporting their findings.

While brainstorming the motor concept in the context of power density and miniaturization, the team discussed how to utilize the space within the center of the rotor. “We realized that it was the most logical space for the differential,” Bach recalled, “because the center of the rotor doesn’t generate torque; it’s typically dead mass within the lamination stack.” They decided to sequester that space and engineer a small, lightweight, high-speed/low-torque differential to reside there. With the diff inside, two planetary gearsets (one each for left and right differential speed) were engineered into the transmission design.

Lucid lighting experts engineered the Air’s LED-based headlamp modules that use a microlens array optical system featuring switchable light channels and a solid-state high beam linked to the car’s steering. Each microlens has a direction and a focal length. Miniaturization of the modules enabled designers to give Air the industry’s slimmest lighting apertures. (Lucid Motors)

The planetaries and their tooth profiles were also designed in house, to meet the team’s stringent spec for “perfect gear meshing under high and low load conditions,” Bach explained. Again, every percent of efficiency gained is important. The gearing is oil lubricated via a small pump that delivers oil from a small sump, through an annulus to cool the stator and end windings. It also lubricates the differential.

“It’s all optimized for efficiency. You can’t achieve the efficiency we wanted in this system by going to an outside supplier,” he said. The heat exchanger mounts directly on the electric machine; pressurized coolant flows in to cool the inverter in situ, transferring the heat into the oil which then cools the drive unit. A look inside the cutaway property reveals the resolver, also an in-house development. Integrated with the rotor shaft, the resolver determines the clocking angle of the rotor. “A motor supplier would not have come up with the idea of integrating the resolver and rotor shaft,” Bach asserted.

Aero chief Jean-Charles Monnet explains how the Air was designed to generate undercar vortices that improve efficiency. (Lindsay Brooke)
Drive module with integrated inverter at top, installed in the Air sedan. (Lindsay Brooke)

Thermal management is another detail noted by the engineers. “We found space for the cooling channels right next to the copper, where the motor heat is created,” Bach explained. “Nobody else has done motor cooling this way because they feel it would weaken the electromagnetic flux,” he said. “But we cultivated an electromagnetic ‘dead zone’ as we call it that doesn’t contribute to torque generation. We cool faster than anybody else. This comes from simulating everything in house.”

Another Lucid technology asset at play on the manufacturing side: The company owns unique, continuous-wave winding equipment to do its motor windings in a dedicated Arizona powertrain factory. Bach describes the machinery as “fully automated, highly scalable, and engineered for high volume manufacturing.” How is Lucid approaching reduction of rare earth metals? The current motor design includes neodymium magnets and “low amounts” of dysprosium, according to Bach. “Our roadmap includes new materials to get rid of rare-earth metals as much as is humanly possible,” he shared.

Like the Lucid motor, transmission unit and battery pack, the power electronics hardware and software are extensively patented. The inverter is a 500-kW design that uses silicon-carbide MOSFET semiconductor technology. It features a proprietary connection system that’s positive and virtually error proof: It connects to the motor when it’s bolted down during assembly. The unit’s close proximity to the motor (about two inches), helps unlock more efficiency in transporting electrons from the inverter, at three phase, into the motor. The inverter-to-motor distance on Tesla S, admittedly a much older vehicle, is about two feet, Hawkins observed: “Another vital fraction of a percent,” he said.

Scaling up

Scale is critical to reducing cost, and the Lucid engineers said their designs will scale according to volume demand without issue. “We realize the ability to manufacture economically is a guarantor of success and for being competitive,” Hawkins stated.

As the company scales up beyond its first product, the team realizes the need for greater rigor in design freeze, further DFMA (design for manufacturability and assembly) advances, and meeting SOP timing. To that end, another VW veteran, Ralph Jakobs, was hired for the new role of VP of program management. “He leads our cycle planning,” Rawlinson said. “It shows how we’re maturing.” Added Bach: “All of our critical thinking has been focused on the Air, but now we are parallelizing the work and creating functional units per the classic matrix organization. But we aim to keep that nimble edge.”