It’s in the powertrain!

The Lucid Air is lauded for efficiency

BY Gordon Hrodda, Member of Denver Electric Vehicle Council

Lucid Air power train

(An earlier rendition of this article appeared at EV4Corners.org)

Here’s why the Lucid is getting rave reviews: the complete power train for the most basic Air weighs only 163 lbs and fits in an airline carry-on bag (including motor, transmission, and inverter). It has triple the power density of the best Tesla equivalent and represents a staggering improvement over an internal combustion engine vehicle.

Lucid is a new entry in the electric vehicle (EV) market, but the company—founded in 2007—has some of the leading engineers on power train efficiency. The current CEO, Peter Rawlinson, headed up development of powertrains for the Tesla S before he left Tesla to best his former employer elsewhere. 

Why is efficiency a big deal? 

Efficiency can be expressed in miles per kilowatt-hour or kwh (common in US; higher is better), or kwh per mile (often done in Europe; lower is better). What most people care about in an EV is range, and the brute force approach taken by many legacy manufacturers is to extend range by including a bigger battery. But batteries are heavy, so larger batteries reduce both range and acceleration, and are unnecessary for the usual short-range trips. With a monster battery, efficiency can drop from 5 miles per kwh to around 3. 

Instead, Lucid reduced the weight of the car, producing a vehicle that is extremely efficient (nearly 5 miles per kwh despite a 118 kwh battery), has unsurpassed range (520 miles), AND accelerates faster than a standard Tesla S.

Furthermore, now that the world knows how to increase efficiency in this way, the technology will eventually become available at lower price points. There is nothing intrinsically expensive about a 163 lb. powertrain other than the development costs.

A future in solid state

The next big efficiency breakthrough will likely be an increase in the power density of the batteries themselves. Preliminary tests of solid state lithium ion batteries, scheduled to be introduced by VW next year, suggest their weight can be decreased by at least 30% due to the elimination of electrolyte.

Additionally, solid state batteries are less prone to fires because the “separator” between the sides of each cell can be made from puncture-resistant ceramic rather than the semi-permeable plastic membrane. This is advantageous because the plastic membrane is subject to puncturing by “dendrite” crystals growing through the separator, shorting the cell.

Dendrites grow during rapid charging, but Lucid engineering has made progress here, too, by enabling charging at the extraordinary 350 kw level. This gains the Air 300 miles of range in a mere 20 minutes, less than it takes to grab a sandwich and a bathroom break while your car charges in the Walmart parking lot. Note that most extant fast chargers do not support such a rapid charge, but newer versions do, and vast numbers of new fast chargers will be appearing in the next few years.

Aerodynamics matter

The Lucid Air’s efficiency and lower weight is attributable in part to a highly aerodynamic shell. In contrast, legacy manufacturers seem to believe that buyers prefer traditional over aerodynamic shapes. The Ford F-150 Lightning, for example, retains the extended hood of the F-150 gas engine truck, even though it is no longer necessary and it blocks the driver’s view. Ditto for the GM Hummer. The cost of this inefficiency comes into play at highway speeds because air resistance increases at a higher mathematical power than velocity.

Lucid points out that at 70 mph, the Air retains a range of greater than 500 miles, whereas the next best range (among vehicles tested at that speed) is the Tesla 3, with a range of 310 miles. An untested model, the Mercedes Benz EQS ($97K – $135K), is also very aerodynamic and likely has a range of approximately 340 miles at 70 mph.

Of course, all of this can and will change. Tesla is now promising to produce a car with a 600 mile range, so competition may be heating up soon!