Hairpin Welding in Electric Motors


The boom in e-mobility is generating an increasing demand for electric motors which are manufactured with solid copper hairpins (wires) in the stator which generate a magnetic field that creates the motion. These copper wires need to be ablated and welded before being ready to use, we discuss these processes below.

Copper hairpin wires are typically lacquered or coated with an organic layer to give them electrical isolation. This layer needs to be removed from the welding zone prior to joining – this can be done by one of our ns pulsed fiber lasers. These wires can take many forms, from small round wire < 3mm to square sections that can be up to 6mm in width. This is a standard ablation task, which is just one of the many applications for which our range of fiber lasers can be used.

Fiber laser welding of hairpins – a solution from SPI Lasers

The challenge when welding hairpins is to produce a high-quality bond with minimized heat input and with minimal spatter. Excessive heating can lead to unwanted burning of the electrically isolating coating and spatter can cause unwanted deposits on the stator with the risk of electrical shorts in the assembly.

Our redPOWER 2kW QUBE single mode fiber lasers are ideally suited to this task and are able to effectively join the copper wires with low heat input and minimal spatter. Using a scanner based optical delivery system the small spot size generated by the high beam quality is moved rapidly in a spiral motion using very high linear speeds. This technique helps to control the weld pool and its stability giving rise to deep penetration, low heat input welds with minimal spatter. The spiralling technique gives a lot of flexibility in tailoring the joint for the shape and size of the wires to be joined.

The surge in the popularity of electric vehicles means that manufacturers face the challenge of needing to deliver high-quality electric motors in volume. SPI fiber lasers are ideal to meet this challenge, as they can be integrated into manufacturing processes seamlessly, enabling the delivery of high-quality batteries in volume.

Welding and ablation solutions and much more from SPI Lasers

Hairpins are just one type of welding, which are made available for users of our fiber lasers. If you are interested in ablation or welding or wider e-mobility and automotive applications then contact SPI Lasers today. Our Continuous Wave and Pulsed fiber lasers can be configured to deliver a variety of applications and solutions, which our experts can discuss with you today.

To download this Applications Postcard as a PDF click here!

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