What is continuous wave winding in an electric motor?

Continuous wave winding forms flat copper wire into its final shape in one bending sequence. It reduces the bend-and-weld steps used in segmented windings, which helps production consistency and drive efficiency. NIO's 925V electric drive uses it, and the project won First Prize at the 2026 China-SAE Science and Technology Award.

Why is continuous wave winding hard to make for a high-power drive motor?

The technique had mostly appeared in small motors with short conductors, so high-power drives had no industry precedent for high-yield production. NIO's team first tried a 180-degree flip-bending method, but repeated rotation stretched the copper and put the insulation at risk. A planar forming design solved the problem.

Is NIO's continuous wave winding in mass production?

Yes. NIO's continuous wave winding technology entered series production in December 2024, and the award project reports production at million-unit scale. NIO's second electric drive plant in Hefei runs a 925V flat-wire stator line that uses three-dimensional integrated wave winding.

How was the NIO 925V drive tested?

The team tested for high-temperature endurance, electrical stress, mechanical vibration and temperature cycling. Results include 1,300 hours of high-temperature running without fault and more than 500 hours of simulated altitude testing at 5,500 metres.

What is boost charging on NIO's 925V drive?

Project data puts peak boost charging power at 202.78 kW. NIO's conference materials describe boost charging as a product of the drive's electronic and software design, giving higher-power charging across a wider voltage range.

What process parameters did NIO report for continuous wave winding?

The process takes 12 flat copper wires, each five metres long, through 24 bends in one pass. It holds the insulation layer to 0.14 mm and motor assembly tolerance to 0.02 mm. NIO reports that its Hefei 925V flat-wire stator line reaches about 94% production efficiency and a qualification rate of roughly 99.6%.

What validation data supports the 925V insulation system?

NIO developed a new insulation material with an international chemical materials company. Validation included 1,300 hours of high-temperature running, more than 500 hours at a simulated 5,500 metres with switching up to 15,000 times per second, random vibration up to 5.5g from three directions, and more than two months between minus 40 and 85 degrees Celsius.

What supply chain and intellectual property detail does the project disclose?

The project names Tongji University, Harbin University of Science and Technology and Baoshan Iron & Steel as partners, alongside an international chemical materials company for insulation. It records 146 authorised patents, participation in drafting six national standards and series production at million-unit scale.

NIO’s continuous wave winding is now in series production

Q: Who won the China-SAE award for this electric drive?

A NIO-led project won First Prize at the 2026 China-SAE Science and Technology Award. Tongji University, Harbin University of Science and Technology and Baoshan Iron & Steel also took part. The project covers a 925V electric drive system built on continuous wave winding.

Q: How well does the 925V continuous wave winding drive perform?

Project data reports a motor power density of 19.06 kW/kg, a controller power density of 226.92 kW/L and a peak boost charging power of 202.78 kW. The motor and controller figures describe separate components.

Category: Automotive, Insulation, Motors, News, Power Electronics, Testing & Validation

Continuous wave winding forms 12 five-metre copper wires into 24 bends in one pass, holding insulation to 0.14 mm

(Image courtesy of NIO)

A NIO-led electric drive project built on continuous wave winding has won First Prize at the 2026 China-SAE Science and Technology Award, and the project data shows how the winding process reached series production. The 925V system reports a motor power density of 19.06 kW/kg, a controller power density of 226.92 kW/L and a peak boost charging power of 202.78 kW, with Tongji University, Harbin University of Science and Technology and Baoshan Iron & Steel among the partners.

Continuous wave winding moves into high-power drives

Continuous wave winding forms flat copper wire into its final shape in one bending sequence, which reduces the bend-and-weld steps of segmented windings and helps improve production consistency and drive efficiency. The approach had mostly appeared in small motors with short conductors, and the industry had no precedent for using it in a high-power drive motor at high yield.

Production readiness came through the forming process, where an initial 180-degree flip-bending method stretched the copper under repeated rotation and put the insulation at risk. A planar forming design avoided that problem, and the final process takes 12 flat copper wires, each five metres long, through 24 bends in one pass while holding the insulation layer to 0.14 mm and motor assembly tolerance to 0.02 mm. Series production began in December 2024, and NIO’s second electric drive plant in Hefei runs a 925V flat-wire stator line that uses three-dimensional integrated wave winding and automated insertion, with the company reporting about 94% production efficiency and a qualification rate of roughly 99.6%.

Insulation and validation behind the continuous wave winding drive

The 925V platform raises the demands on insulation control, so the team worked with an international chemical materials company to develop a new insulation material from scratch. Validation then covered high-temperature endurance, electrical stress, mechanical vibration and temperature cycling.

In high-temperature running, the system completed 1,300 hours without fault. A separate programme simulated an altitude of 5,500 metres and combined sustained high voltage, switching at up to 15,000 times per second and sudden rises in motor speed, accumulating more than 500 hours. The team applied random vibration of up to 5.5g from three directions, and the system also ran between minus 40°C and 85°C for more than two months.

Boost charging and production scale

Project data puts peak boost charging power at 202.78 kW. NIO’s conference materials describe the function as a product of the drive’s electronic and software design, giving higher-power charging across a wider voltage range.

Behind the drive sit 146 authorised patents and participation in drafting six national standards, with series production running at million-unit scale.

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