The Role of Fiber Lasers in Electric Motors (E-Motors) Production

The world is embracing a fundamental shift from internal combustion engine (ICE) vehicles to electric vehicles of all shapes and sizes. Although electric vehicle technology has existed for some time, it will need to evolve to embrace the mass production volumes required by this emerging industry. One such area is in the mass production of electric motors; we go on to explore how fiber lasers are ideal for this task.

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SPI fiber lasers deliver ablation suitable for hairpin ablation in electric motor stators

The difference between electric motors and ICE engines

There is a clear difference between electric motors and ICE engines, this was summarised by Princeton University as:

  • A motor is a machine that converts other forms of energy into mechanical energy and so imparts motion.
  • An engine is a motor that converts thermal energy to mechanical work. So, an engine is a specific type of motor.

In industry, the two terms above are used interchangeably, but there is a clear difference between how electric motors, which convert electricity into motion whereas ICE engines convert fuel (e.g. petrol and diesel) into motion. Of course, there are also hybrid models available too, which actually use both electric and ICE technologies, using fuel as top-up/back-up where electric power is not available.

Electric motors improved reliability through simpler technology

Simply stated electric motors are simpler technology than internal combustion engines (ICE). The vastly fewer number of parts in an electric vehicle motor will improve reliability for drivers as the vehicle has much less chance of failure due to the fact fewer parts can fail. Conversely, the ICE has literally hundreds of moving parts, which dramatically make the engine at much higher risk of failure.

Fiber lasers have a valuable role to play in e-motors production

As in many areas of automotive manufacturing, fiber lasers have a valuable role to play, this is certainly the case in e-motors production – particularly in ablation and welding applications. For further information visit the “Hairpin ablation and welding for electric motors” section of our article –

Hairpin ablation (stripping) in electric motors

Electric motors are manufactured with solid copper hairpins within the stator. These create a magnetic field, which turns electrical energy into mechanical energy creating motion.

During the manufacturing process, the copper hairpins are coated with an organic layer coating (and possibly also glue), which gives them electrical isolation. Due to subsequent welding processes, the coating needs to be partially removed to ensure that strong welding joins are attained. The copper wires vary in shape (some might be round, others square, etc.) and size (which are most typically between 3mm and 6mm in width).

Historically the lacquer coating was removed through manual techniques such as wire brushing, which can leave a lot of dust and debris. Alternatively, CO2 lasers have been used but these can leave fine residues, which can cause problems if the hairpins are not fully cleaned.

Our redENERGY G4 pulsed fiber lasers are ideal for the hairpin ablation task, the coating layer can be removed through ablation back to the bare metal. This process will leave absolutely no residue behind and will set-up the hairpin ideally for the later welding processes. In particular the precision levels of a fiber laser will be extremely valuable. The precision ensures absolute alignment of the hairpins to the stator as well as elimination of all defect. These defects increase resistance and in doing so would reduce the efficiency overall of the electric motor.

Hairpin welding of electric motors

To create a strong and stable magnetic field, traditionally the stators in electric motors are created through the manual winding of copper wire. In a process, which has some similarities to knitting the stator is wrapped one slot (sometimes called groove) at a time with copper wire. This process is challenging, time-consuming and is prone to error.

A new process called “hairpin technology” has evolved specifically for electric motors which automates this process. Traditional approaches would not work for electric motors as the copper wires are too thick and the process would be too time-consuming to produce for the quantity of electric motors required. Fiber lasers are ideal for entirely automating this process, which is delivered with no contact and with minimal heat input and splatter.

The welding of hairpins in electric motors is efficiently delivered through fiber lasers

The welding of hairpins in electric motors is efficiently delivered through fiber lasers

The process involves the firing of rectangular copper wire (which is shaped just like a hairpin) onto each slot of the stator. The fiber laser only requires one shot and precisely fills the required space with copper. Precision welding is then applied to each slot ensuring the copper delivers maximum electrical conductivity of the motor is achieved in day to day use.

Any loose edges and protruding parts are welded to form a seamless surface by the laser in fractions of a second, this again ensures the efficiency of operation. This process can be repeated and integrated easily into an assembly line manufacturing process, significantly easing mass production requirements. The process is particularly ideal as it can be implemented in the required large manufacturing volumes, with absolute precision and delivered error-free.

Related articles from SPI Lasers

Here are some related articles from SPI Lasers on e-mobility and electric motor related topics:

Contact SPI Lasers for e-Motors and fiber lasers advice

We hope you have found this article informative and thought-provoking. We believe that fiber lasers will play a massive role in e-Motor production and wider e-mobility initiatives too. Why not contact us to discuss the SPI range of Pulsed and Continuous Wave fiber laser models, we can advise on which would work best for your requirements. If you would like to receive regular updates from SPI Lasers, click this link.


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