“Audi Hungaria begins series production of electric motors.” The title of the press release in late July had a coolly professional, clinical, decidedly unspectacular ring to it. In reality, it heralded nothing short of a production revolution in the Volkswagen Group. For the first time, the group is building an electric motor from the ground up in Győr. And what a motor it is: the new motor is being produced for the Audi e-tron, which will be manufactured in Brussels. This first fully electric SUV from Audi will debut on September 17. One thing is already clear: It will deliver an unprecedented range.
But let’s back up a bit: Electric motors are not exactly a revolutionary novelty in themselves. Humanity has been using them for 200 years. The first electric motor was built in 1825 and – in an interesting historical twist in light of the current production in Győr – has since been closely associated with the name of the Hungarian scientist Anyos Jedlik. One encounters electric motors frequently in everyday life. Garden tools and household appliances are driven by them. But implementing an electric motor in a car is a far more complex undertaking. It requires a complex, more powerful and more reliable system than a lawn mower or a vacuum cleaner.
Electric energy is environmentally friendly. No hazardous substances are emitted during its use. This means that it helps keep the air in cities cleaner and mitigates the greenhouse effect. The prerequisite for zero-emission mobility is therefore already in place. So when the energy is produced in an environmentally friendly manner (i.e. by “green” energy sources such as wind turbines), the environmental impact is zero.
Simpler in Structure – More Challenging in the Details
At first glance, the structure of an electric motor seems simple compared to that of a combustion engine, consisting as it does of fewer parts: no fuel system (though it does have a battery), no complex transmission system (electric motors make do with a single gear), no combustion engine, no clutch, no turbochargers, no spark plugs, no engine and transmission oil, no cardan shaft.
In spite of its simplicity, Audi faced a plethora of challenges in developing the electric motor. The biggest: To date, none of the electric motors familiar to us in everyday life has been called upon to deliver the kind of capacity required to power a vehicle like the Audi e-tron and provide the desired high range.
After complex calculations and simulations, Audi opted for what is known as an asynchronous electric motor – the electric motor with the simplest construction. It does not require any expensive magnets. Beyond its simplicity, the motor’s greatest advantage lies in its reliable and robust construction. One challenge, however, is that it requires large dimensions and a lot of weight to produce a lot of power, which is a drawback when it comes to the question of economical operation. Developers were faced with a conundrum: generating enough power with the smallest possible dimensions and weight. The second big expectation was that this power would be reliably assured throughout the entire lifetime of the vehicle – ideally without maintenance.
The development of electric motors at Audi takes place in a division of labor between Ingolstadt and Győr. The German colleagues are responsible for the development of the design and active components. This includes all parts in which electricity flows. The team in Győr is responsible for the passive components, such as cast parts.
Premium Quality from the Word Go
The new electric motors from Audi have to display premium quality from the outset. So they are carefully examined on three internal test benches in Győr, where they run in preconfigured programs. The motors must also demonstrate their quality in climate chambers as well. Such chambers simulate temperatures from minus 40 to 105 (!) degrees Celsius. For electric motors in particular, it is crucial to determine how they work at high temperatures, because electric motors can self-destruct if they overheat. An electric motor has to put in over 1000 hours on test benches, which corresponds to an entire vehicle lifetime. On test benches, it all takes place in less than two months.
“In testing, we conduct fatigue tests under changing mechanical and temperature conditions in accordance with the lifetime of the products,” says Alexander Dudas, the coordinator of the testing team. “To do that, we have three back-to-back test benches with climate chambers at our disposal.” This, too, is unique within the group.
The e-production technology center was formed in 2013. “Our principal task was to acquire the requisite know-how for electric motor production. This meant familiarizing ourselves with and testing various production technologies. In practice, this meant creating prototypes,” says technician Sándor Dombi of the early days of the center. The first motors were produced in 2014. These trial motors ultimately aided the process of final motor development. A year later, in 2015, the series production processes were put in place. And they soon had to prove their mettle in practice.
Employees with Special Knowledge In-Demand
The number of employees in the workshop, which is unique within the Audi Group, has grown steadily since its inception. Hiring new personnel was not an easy matter, however; the task, ultimately, was to find employees with very special skills to work in a highly secret field. “The biggest challenge was to find specialists in the field of coils,” says Dombi. There are currently 23 technicians, supported by four engineers, working at the e-production technology center.
The manufacture of the completely new electric motors was a huge challenge for everyone in Győr. Robert Kovacs, director of the production planning project team, sums it up as follows: “We have a lot of experience in the construction of cylinder heads and engine blocks. But now we had to figure out the whole business of coiling copper wires.” The production line is comprised of two parts: a stator production line and an assembly line. The most exciting part of the stator line is the winding and inserting center, where the copper wires are wound and pulled into the grooves of the casing. These are the critical moments in electric motor production. “That’s why we worked together with the machine supplier to develop a special solution. In other places, these steps are executed with two different machines. By contrast, we have found an integrated solution for both,” explains Kovacs. At four meters tall the biggest facility in the hall, the station is all but impossible to overlook.
The stator (also: stand, from the Latin root “stare“= stand) is the fixed, stationary part of a device, particularly where there is also a rotor. A stator may be found, for example, in an electric motor or a pump. The stator is the counterpart to the moving part, the rotor. The stator is frequently also the housing and in the case of electric motors and generators is, with rare exceptions, made of “electrical steel”. Here it also functions as the shared core for the induction coils.
Inserting As Much Copper Wire As Possible
The usual processes are scarcely to be found at the other stations of the production line either. “The next production steps are contacting and wrapping. In the contacting step, the copper wires are welded into the terminal, and in the wrapping step the coils are wrapped. The last important step is the impregnation, in which the finished stator is dipped in resin and thus fixed,” says expert Kovacs, explaining the details of electric motor production.
The electric motor from Győr features numerous innovations. With the stator – one of the core components of the motor – the aim is to insert as much of the thin enameled copper wire as possible into the casing. The tighter the winding, the more efficient the power delivery. A new winding and inserting center at Audi Hungaria makes it possible to wind the optimal amount of enameled copper wire extremely compactly and then insert it into the casing.
Electric Motors Have Unions Too
The familiar union process takes place in electric motor manufacturing as well. The term comes from conventional automobile manufacturing. It describes the moment when the engine and the transmission are united. With an electric motor, the gear wheels must be very precisely coupled and coordinated with each other – the electric union, as it were. For this production step, the colleagues in Győr set up an automatic station. Designing it called for a great deal of creativity, as there was no existing solution on the market.
Another special feature of the assembly process is that the production does not take place on a line, but in production islands. This operating principle is known as modular assembly. The function of the line, i.e. passing on the workpieces, is handled in Győr by driverless transport vehicles (AGVs). These vehicles are already in use in multiple locations in Audi Hungaria. Nowhere, however, are they used for such complex tasks as that of electric motor production. The AGVs are guided by a dynamic system, with their routes determined by smart algorithms. The vehicles communicate with the stations as well, asking whether they are free or currently working and bring workpieces to the stations that are currently free based on the replies they receive.
One-Shift Motor Production, Soon to Be Three
Audi Hungaria has broken new ground in multiple areas. The production of electric motors has brought everyone involved in the project a wealth of new skills and posed many new challenges as well. With the experts sprinting down the homestretch, the herculean efforts of the departments over the past five years will soon bear fruit: Series production of the electric motors is set to begin shortly.
The current production capacity is around 400 electric motors daily. This will be ramped up gradually. There are currently around 100 employees involved in the completely new production process, and by the end of the year that number will rise to over 130. Production is currently a one-shift operation. Soon, however, electric motor production in Győr will move to a three-shift structure.