How Lucid Surpasses Tesla With Smaller Motors

Lucid Motors calls its engine design miniaturized, and it’s long boasted that the lightweight and “incredibly compact” engine in its Air electric sedan is lean enough to fit in an airplane carry-on.

Lean and small is only one aspect, however. Lucid’s motors weigh just 67 pounds each and are capable of generating 670 hp – yes, that’s 10 hp per pound.

2022 Lucid Air

Additionally, Lucid’s silicon carbide reverse gear, reduction gear, and differential, packaged together, weigh approximately 163 pounds.

It is very, very power dense. And in a tech talk released by the company on Tuesday, Lucid CEO and CTO Peter Rawlinson and VP of Powertrain Emad Dlala went over the priorities around which the engines were designed, and how power and efficiency, through low resistance and thermal management, were part of the plan from the start, along with ease of manufacture.

You’ll want to watch the whole presentation – over an hour long – for the physics lesson inside, and you’ll learn a lot about not just this unit, but motors in general. But these four slides, comparing Lucid’s engine to Tesla’s and Porsche’s engines, cut to the chase.

Lucid weight of stator and rotor compared

Lucid weight of stator and rotor compared

Lucid Engine Weight Compared

Lucid Engine Weight Compared

Lucid Power Density Compared

Lucid Power Density Compared

Lucid power and engine weight compared

Lucid power and engine weight compared

Rawlinson notes that the project included a return to physics and examining the entire powertrain as one holistic inertial system.

The two spend a lot of time discussing the design of the stator, the static outer part of the motor which, together with the current shaped by the inverter, creates the magnetic field that spins the rotor in the middle.

For example, Lucid’s six-pole permanent magnet synchronous motor stator doesn’t use copper wire windings like many of these motors, nor does it use hairpins. Instead, for lower power losses and ease of assembly, Lucid turns to a continuous-wound assembly that wraps into the stator with a limited number of welds. It is made with a CNC machine and a process that resembles weaving. Then a CNC-controlled mandrel helps align and insert the woven mesh.

Carbon Wrap on Tesla Model S Engine Poster

Carbon Wrap on Tesla Model S Engine Poster

The pair even poke fun at the workaround Tesla resorted to in its engines for the Plaid – a carbon fiber shell that Rawlinson says is the same type of technology used in hydrogen storage for fuel cells, to maintain enormous pressure. scale that high volume is going to be very expensive, speculates Dlala.

Lucid also cools its motor differently than Tesla, Porsche, or any other design we know of. Lucid’s strategy extracts all the heat it can super close to the slots rather than waiting for the heat to reach the outside. A central channel in the stator functions as a collector, passing ATF (automatic transmission fluid) through narrow channels, helping to extract heat through this mesh.

The busbars connecting the motor to the inverter are also as short as possible, to reduce resistance (and therefore heat). This is an advantage of the motor because it was designed as a single unit with the inverter.

Lucid's Rawlinson and Dlala introducing the training unit

Lucid’s Rawlinson and Dlala introducing the training unit

Conclusion: Lucid emphasizes that its drive units are lightweight, compact, efficient, power-dense, and scalable.

While Lucid doesn’t actually present an analysis of how efficient the motor unit is compared to the unit of the Taycan and Model S Plaid, it does imply, based on the entire presentation, that its motors contribute also greatly to efficiency.

At this point, Rawlinson dares that the motor itself weighs so little – only 11% of the total battery mass – that if they can achieve this efficiency gain through the design of the unit, it will essentially acts as a “zero-mass drive unit”.

Maybe that’s the point to help give Lucid an edge in the future, as it produces electric vehicles that go further with smaller batteries and, perhaps, a scaled-down version of this unit .

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