Webasto joins hands with Tongkuai to lead the new trend of electric vehicle technology

In the process of selecting electric vehicles, the effectiveness of the heating system is often overlooked. However, this system is crucial for providing a warm and comfortable driving environment and removing frost and fog from winter windows. More importantly, it can also improve battery efficiency, as the battery performs best within a specific temperature range.

Unlike internal combustion engines that generate waste heat, electric motors require an independent auxiliary heating system that obtains electricity from the battery and uses heating media such as coolant or battery oil to generate heat. In the design concept of electric vehicles, the lightweight and miniaturization of heating units are key. As a leader in automotive heating technology, Webasto has achieved significant success in this area.

Webasto's latest high-pressure heater is not only suitable for various electric vehicle system voltages, but also has continuous adjustable power, further stabilizing the on-board electrical system. This innovative achievement benefits from three advanced laser application technologies provided by Trumpf.

01 Webasto achieves efficient airtight welding of electric vehicle heaters
At the Webasto factory in New Brandenburg, Germany, J? Rn Schmalenberg serves as the head of production engineering and leads the manufacturing of electric vehicle heaters. The heater components produced by this factory account for 95% of the total amount manufactured by the company for internal combustion engines and electric vehicles. Millions of products are manufactured using reliable high-performance new energy vehicle laser processing technology and sold worldwide. He pointed out, "The working principle of electric vehicle heaters is the same as other heaters: the liquid is heated through a heat exchanger and then transported through pipelines. The liquid is incompatible with high voltage, so ensuring the sealing of the shell is crucial."

For this reason, Webasto adopts a lightweight die cast aluminum casing. Although traditional high vacuum electron beam welding is a method for achieving airtight welding of this material, it is costly and inefficient. Therefore, a fast TruDisk disc laser that can operate at atmospheric pressure without the need for protective gas was adopted. In an ideal situation, this type of laser needs to work as quickly and strongly as possible, with the aim of producing a non porous weld seam. If the laser works slowly at low power, pores may form when the material melts, resulting in the inability of the casing to maintain airtightness. Schmalenberg explained, "Using a 16kW TruDisk disc laser, we adopted the 'sledgehammer' effect, so there was no time for bubbles to form from the beginning."

It is crucial for the laser to generate the largest possible keyhole. "High laser power produces stable keyholes. The more you use, the better the effect," Schmalenberg explained. Webasto is very satisfied with the current results, but is also considering combining this application with new multifocal optical technology. This technology divides the laser beam into four independent light spots arranged in a square shape, so that their effective radii overlap, forming a very large keyhole. The laser power is evenly distributed throughout the entire working area, keeping the keyhole open without collapsing and without pores.

Figure 1: Webasto uses TruDisk, which can be operated without the need for protective gas, with the goal of manufacturing seamless welds

02 Green laser assists Webasto in achieving high-precision copper welding
In Webasto's precision manufacturing process, the sealing welding of the casing is only the beginning, followed by the connection of heating elements, which is the key to technological breakthroughs. Copper, with its excellent electrical conductivity, plays a core role in this process. Schmalenberg pointed out that "the high reflectivity of copper and its mating components greatly increases the difficulty of laser welding." More importantly, the weld depth of the heating unit must be strictly controlled to avoid damaging the sensitive layers below. "Accurate control of laser welding depth is crucial, and traditional near-infrared new energy vehicle laser processing technology is inadequate in this regard."

Green laser solves this problem with its high absorption rate wavelength for copper. Through precise pulse control, a consistent and extremely accurate welding effect is achieved without worrying about splashing and eliminating the use of protective gas. The TruDisk Pulse laser, with a power of 4kW and a pulse width of milliseconds, easily meets challenges. Schmalenberg proudly said, "There are no defects in millions of components, which makes our work more relaxed. Nowadays, our copper welding work relies entirely on green light pulse lasers, and near-infrared laser processing technology has become history."

Figure 2: The wavelength of the green laser is well absorbed by copper

03 Webasto uses ultra precision laser technology to create extremely flat heating elements
After Webasto was satisfied with the quality of copper welding, the next step was to turn to the manufacturing of heating elements. At this time, the company's unique thin film technology shone brightly. Webasto does not simply attach independent conductors, but directly etches the conductors into a thin metal layer to keep the heater as flat as possible. Schmalenberg stated, "When etching materials, extremely high precision is required to prevent laser penetration from penetrating too deep and damaging the underlying layers." Therefore, Webasto chose the TruMicro series ultra short pulse laser to achieve "clean etching and precise edges. Avoiding any melting phenomenon is crucial as it may cause defects. Ultra short pulse lasers can directly transform materials from solid to gas, without which we cannot achieve such flat product designs."

The ultra flat heating unit design means it can be installed very close to components carrying coolant. "This close proximity layout ensures extremely fast response when heating the coolant," proudly said. "In addition, the special design also means that the heating power can be almost continuously adjusted at 400V and 800V. We are the first company to provide this feature." During peak voltage periods, the heater also acts as a small capacitor to help stabilize the in car electrical system. ". Production in high wage countries like Germany requires a high degree of automation and innovation.

Figure 3: Webasto adopts a fast ultra short pulse laser to achieve a flattened design

The ultra flat design of the heater unit means it can be installed very close to the components carrying coolant. "This proximity ensures an extremely fast response time when heating the coolant. More importantly, its special design allows for almost continuous adjustment of heating power between 400 and 800 volts - we were the first company to provide this feature," Schmalenberg proudly said. During the peak voltage period, the heater also acts as a small capacitor, helping to stabilize the onboard electrical system.

For companies like Webasto, this means they must adopt advanced new energy vehicle laser processing technology. As explained, this makes Webasto the world's preferred partner: "It can be said with certainty that many electric vehicles produced around the world are equipped with top-notch electrical components from European manufacturers like us on assembly lines."

Source: Trumpf