An overly strong spring is the root cause of a rather scary issue, with the startup now looking at 637 potentially affected EVs.
Sudden loss of power can be a terrifying experience behind the wheel, especially if you're cruising at speed on the highway. Certain examples of 2022 and 2023 Lucid Air EVs are susceptible to this issue, spawning a major recall by the startup automaker. Abe Mccb
According to the NHTSA report, the issue concerns the vehicle's primary contactor. This is an electronically activated switch that is responsible for connecting the main traction battery to the rest of the vehicle. When the EV is started, power from the 12v battery energizes an electromagnet in the contactor, which closes a switch connecting the high-voltage traction battery to the motor controller and other vehicle systems. When the vehicle is switched off, the contactor's electromagnet is de-energized and a spring returns it to an open position. The problem is that if the contactor switches off unexpectedly while driving, the vehicle's motors will lose power.
The matter first came to Lucid's attention after a vehicle was presented to its service center in May 2022 with a loss of power condition. The Lucid Air uses contactors manufactured by Sensata Technologies in vehicles from the 2022 and 2023 model years. Investigation revealed that the contactors were manufactured with a spring that was too strong for the contactor's magnetic field. Thus, under certain conditions, the contactor would snap back to its open position unexpectedly, cutting power from the battery to the motors.
Lucid has used an over-the-air update to investigate the prevalence of the problem in its vehicles. The company determined that affected contactors would exhibit a "double-dip" in current flow when they were first energized, as the magnetic field fought to close the switch against the excessively-strong spring. Ideally, the contactor should make a clean connection in a single movement, and exhibit a single dip in current flow on connection. Vehicles that exhibit this behavior more than 5% of the time are considered at high risk of sudden contactor cut-out and will be recalled.
Thus far, the company has identified 273 vehicles fitted with at-risk contactors. A further 336 vehicles built by Lucid haven't had the OTA update required to diagnose the issue. In this case, Lucid expects that approximately 20 more vehicles may be fitted with contactors in need of replacement. Overall, the company considers that a full 637 vehicles could be affected, but estimates just 6% of that population will actually be defective.
The fix involves replacing the defective contactors with a new part. The replacement parts have been redesigned with a stronger magnetic field to counteract the strength of the spring. They have also been tested by Lucid to exhibit the appropriate single-dip current signature on closing.
Going forward, Lucid is reaching out to owners of the 237 affected vehicles by mail to arrange a no-cost repair. For owners of vehicles that have yet to be updated to analyze their status, they will be notified to arrange a software update. From there, their vehicles will be assessed as to their need for a contactor replacement.
A sudden loss of drive is at best, concerning, and at worst, a dire hazard on the road. Lucid's recall should fix the issue in short order. In the meantime, owners should seek the latest software updates available and verify with their dealer that their car is not subject to this issue.
Got a tip? Let the author know: lewin@thedrive.com
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