Vitesco Brings Advanced EV Motor Design and Manufacturing to Kia

Technology in the EV industry advances incrementally, with carmakers and suppliers whittling away at challenges one obstacle at a time. Supplying the electric motor for the Kia EV9, Vitesco Technologies has innovated by incorporating six connectors for the 3-phase electric motor, letting it switch between a Wye configuration and a Delta configuration depending on driving conditions.

But it was other details of the motor that impressed Munro Live lead electric machine engineer Paul Turnbull when that company conducted a tear-down analysis of the EV9.

Vitesco Technologies was created in September 2021, when Continental spun off its EV technology division into a standalone company. Since that time, Vitesco has announced a technical partnership with German semiconductor giant Infineon and has merged with motion control specialist Schaeffler AG.

The company’s expertise in designing and manufacturing sophisticated EV motors is evident in the details of the EV9’s motor, Turnbull said in his Munro Live YouTube video analysis. “Not every electric machine developer is able to do these bar-wound, interior-magnet machines with this kind of quality,” he observed. “I want to point out the uniform spacing between the conductors and how every single conductor has the same exact bend in it.”

Related:Vitesco Reveals Lower-Cost EV Power Module

That uniformity is crucial for durability. “When the conductors get too close, or bent in a non-uniform way, then you can end up getting shorts after a durability test,” Turnbull explained. He also cited the high quality of the welds on connections in the motor. “Getting the welds right on an electric machine is the big part of the quality of the machine.”

The EV9’s motor is in many ways an example of how increasing understanding of how to optimize EV motor design is producing a convergence, much in the same way that combustion engines have converged on very similar designs using 500 cc cylinders for optimum thermal efficiency.

“It is an 8-pole, 48-slot machine,” Turnbull observed. “This one has ten conductors per slot. It is the kind of design that just about all of the EV makers that here at Munro, when we tear them apart we look for similarities, just about everybody is converging towards this interior-magnet, bar-wound type of machine across the board.”

The earlier design's laminations (left) were prone to getting bent during handling, while the new design stakes the top layer down with "stitches" to prevent that from happening. MUNRO LIVE

One feature of Vitesco’s EV9 motor caught Turnbull’s eye because it showed that the company is attending to the finest details of quality control. Motor housings are built up from countless layers of thin laminations of metal that stack up to create the complete housing.

Related:Deep Dive Into Kia’s Innovative Dual-Wye-and-Delta EV Motor Configurations

“On the older design, you can see that the lamination around the mounting points can sometimes bend up,” he pointed out. This would never matter to a customer because this can’t happen to a motor that hasn’t been removed from the car, Turnbull admitted.

“This of course happened during our handling, but it can happen in process and that can cause some trouble,” he said. So while this could never happen to a motor that is already installed, there was the potential it could get bent during handling before or during installation. Vitesco recognized this possibility and took action to prevent it.

“What they’ve done here is they’ve added four little, what we call ‘stitches,’ where they indent the material to make one lamination lock into the next to make sure that the laminations stay put even out here at the mounting feet,” he pointed out. “Little details like that are the sign of a supplier that knows what they are doing.”

“Props to Vitesco for making a high-quality machine,” Turnbull concluded.