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Electromobility is more than just a trend; it is on its way directly to the mass market. Companies such as the laser specialist TRUMPF see it as a great opportunity for both themselves and German industry because automobile manufacturers need innovative technologies for mass production. They require robust processes that can be quickly scaled from today’s low production volumes to mass production. This calls for expertise in two areas: laser technology and digitization. Laser technology can efficiently and affordably manufacture the key components of electromobility, such as electric drives, power electronics, and batteries. Digitization is necessary to meet the production requirements of the automotive industry – maximum utilization of capacity and maximum flexibility.

Electric mobility is on the rise worldwide. In 2017, more than one million electric cars were registered for the first time over the course of one year. This amounts to 57 percent more than in the previous year. China is the front runner with around 60 percent of all new registrations, followed by Europe and the USA. Delivery services and logistics service providers all over the world are also converting their fleets to emission-free electric vehicles, such as Deutsche Post with its StreetScooter. Impending driving bans in major cities suggest that the number of e-cars will continue to increase.

The growing demand for electric mobility is also becoming apparent at TRUMPF: Every tenth euro of the Ditzingen-based high-tech company’s sales in the automotive sector can be attributed to battery production – and the trend is rising. “We have the right manufacturing processes in place to economically manufacture the central components required for mobility in the future: Only lasers can produce electric drives, high-performance electronics, and batteries in series so flexibly and at such a top level of performance,” says Christian Schmitz, chief executive officer of laser technology at TRUMPF.

New Hairpin Technology Reduces Cost of E-Motor

Automotive manufacturers are increasingly relying on so-called hairpin technology for electric motors. To generate a stable magnetic field, the stators (i.e., the immovable parts of an electric motor) are typically wound with copper wire. Each individual groove of the carrier unit is wrapped – the way a knitting needle is used. Due to the thick copper wires, this is too complex and time-consuming for strong electric motors designed to drive a car. In the hairpin process, a compressed-air pistol shoots preformed “hairpins” made of rectangular copper wire into grooves at the edge of the motor. The wires are then wound together and welded. The highest precision is required to maintain the electrical conductivity of the copper. Such clean and precise welds can only be achieved with lasers. “With our welding process for the hairpins, we ensure that electric motors can be manufactured quickly, safely, and cost effectively. The costly and time-consuming winding of coils with thick copper wires for strong electric motors is no longer necessary. This makes mass production considerably easier,” says Schmitz.

“Green Technology” for High-Performance Electronics

The designers relied on copper not only for the engine. While a 24-volt battery sufficiently powers the complete electronics of a combustion engine, voltages of around 800 volts are quickly generated in an electric car. To withstand this load, the designers use the excellent heat and power conduction properties of copper. However, the same capabilities of this metal also pose challenges: Laser welding normally uses infrared radiation. But it is precisely in the wavelength range of around 1000 nm that copper exhibits highly-reflective properties. Depending on the surface condition, uniform weld seams can therefore only be guaranteed to a certain extent – and is oftentimes not high enough for industrial purposes. Deep penetration welding can also produce spatter that damages the component and, in a worst-case scenario, leads to short circuits on the boards.

TRUMPF has therefore developed a solution using a green laser. The green wavelength is absorbed much better by copper. Because the material reaches its melting temperature faster, the welding process starts more quickly and requires less laser power. While the infrared laser operates at 2.6 kilowatts of peak pulse power, the green laser uses 1.4 kilowatts for the same weld seam. This process is more energy efficient and produces significantly less spatter. This means that copper welds are always produced with consistent quality on every type of surface.

“In addition to factors such as the correct wavelength, laser optics also make a critical contribution to the precision of laser welding processes,” explains Barbara Herdt, product engineer at LASER COMPONENTS. “They bundle the laser beam with all its energy onto a small spot. Due to the high energy of industrial lasers, a high laser damage threshold is a crucial factor. For special requirements, DOEs can be used to implement a wide variety of beam shapes.”

With these and other laser processes for electronic components, all 200 or so welds of an electric motor can be performed in just over a minute. The charger plug, current transformer, and rectifier are examples of the range of new power electronics being introduced into the car.

Digitization for Secure Battery Production

In addition to the production of motors and electronics, laser technology also plays a crucial role in the production of batteries. In this area alone, TRUMPF has already sold more than 500 lasers. The batteries consist of several layers of wafer-thin copper and aluminum foils, which are cut with the laser. The battery is then filled with liquid electrolyte and welded shut with a lid. These welds must be tightly sealed: if the battery breaks down during operation, there is a risk of fire and injury. From the battery cell via the battery module to the battery pack, the laser takes over all welding processes. The laser systems have sensor systems and are connected to a cloud solution via software. The sensors provide values for quality assurance and documentation but also control the welding process.

Battery production requires not only know-how in laser technology but also in digitization. This is because process monitoring is an important basis for stable production, especially in battery production for electric cars. “Battery manufacturers are faced with the problem that they can only test the functionality of the battery at the end of the production process. They need continuous monitoring of this process to ensure that the battery functions properly at the end of the process,” says Schmitz. In addition, digitization can generate data that is of interest to the end customer, including performance data, speed data, and sensor data that lists both the welding result and the seam width.

With this data, the manufacturer can document the quality of production, detect deviations from the standard, and intervene at an early stage. In addition, manufacturers are increasingly relying on maximum flexibility in their systems. They produce different types of engines – both internal combustion engines and electric cars – on one and the same production line. This flexibility can only be achieved if systems are digitized and intelligently networked.

Not Only Cars Drive Electric

The market potential of electric mobility is only just beginning to fully unfold because mobility via electric traction drive means more than just electric cars. Fully electric trucks with overhead lines are currently undergoing practical testing in Sweden and Germany; in Norway, the first strictly battery-powered passenger and car ferries are already in operation; in many parts of the world, municipalities are relying on electric street cleaning and gritting vehicles; the first fully electric tractors are already quietly plowing furrows through fields; bicycles supported by an electric motor have enjoyed growing popularity for years; and electric scooters are a market with millions sold per year, especially in East and Southeast Asia. All these e-vehicles require batteries, power electronics, and electric motors.

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It is all about Optics

In many areas, laser material processing has become part of everyday production. The quality of industrial lasers in any application mainly depends on the shape, guidance and other beam parameters, and therefore on the optical components used in the machine.

At LASER COMPONENTS, we help you to find a solution that matches the power, wavelength and intended application of your industrial laser. In our optics manufacturing facilities, we use various coating methods to ensure that your optics always meet the highest quality standards – be it for single products or an entire series.

Datasheet:

Further product information:
Coated Laser Optics

Manufacturer:
LASER COMPONENTS Germany / Laser Optics

Contact:

Contact Person:	Fredrik Wikfeldt
Company:	Laser Components Nordic AB
Address:	Skars led 3
ZIP / City:	41263 Göteborg - Sweden
Phone:	+46 (0)73 848 77 22
Fax:	+46 (0)31 703 71 01
Email:	f.wikfeldt@lasercomponents.se