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From cylinders to coils: the revolution of electric motor

27.9.2018
From cylinders to coils: the revolution of electric motor

From combustion engines to electric motors: how is the Volkswagen Group managing this revolution in production? The new era has already begun at the Audi plant in Győr.

In July, at the Group’s plant in Győr, series production began on the motor which will provide the traction for the Audi e-tron, the brand’s new zero-emission SUV.

An important moment, marking what could be considered a genuine revolution. In short, you could say that we’ve moved from cylinders and engine blocks to coils of copper wire!

Electric motors have been around for nearly 200 years, and are used in a huge variety of day-to-day objects, in various shapes and sizes. But designing an electric motor for a car is a far more complex undertaking, even though its structure seems simple compared to that of an internal combustion engine. It consists of fewer parts: no fuel and no exhaust system, no transmission, no clutch and no turbochargers, just to name a few.

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The challenges to overcome

In spite of its apparent simplicity, Audi faced a plethora of challenges in developing the e-tron motor. The biggest? Delivering the kind of capacity required to power such a vehicle and provide the desired high range. After complex calculations and simulations, Audi opted for what is known as an asynchronous electric motor – the simplest solution, given that it does not require any expensive magnets, and with the key advantages of its reliable and robust construction. One challenge, however, is that it requires large dimensions and a lot of weight to produce enough power. The designers were faced with a conundrum: generating enough power with the smallest possible dimensions and weight.

The second big challenge was for this power to be reliably assured throughout the entire lifetime of the vehicle – ideally without maintenance. The development of electric motors at Audi is split between two teams, based at Ingolstadt and Győr, where they racked up over 1,000 hours of testing on three specific test benches, simulating the vehicle’s entire life cycle in just under two months. The motors also had to demonstrate their quality in climate chambers as well, simulating temperatures from -40 to 105° C: particularly challenging conditions especially for electric motors, because they can self-destruct if they overheat.

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New expertise, new processes

The process was a long one: the first motors were produced in 2014, while a year later, in 2015, the series production processes were put in place. The Győr plant is also unique in terms of its employees: the number has grown steadily since its inception. Hiring new personnel was not an easy matter, however, as employees with very special skills were needed to work in a highly secret field. The biggest challenge was to find specialists in the field of coils, who are quite rare to begin with! There are currently 23 specialist technicians, supported by four engineers, working at the e-production technology centre.

The production line is divided into two parts: a production line for the stator – the key component – and an assembly line for the entire motor. Another special feature of the assembly process is that the production does not take place on a line. The various phases are performed in separate islands, an operating principle known as modular assembly. The components are taken from one station to the next by automated guided vehicles (AGVs), guided by a dynamic system, with their routes determined by smart algorithms. The AGVs communicate with the stations as well, asking whether they are ready for the components, in order to take workpieces to the stations that are actually ready for them.

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The current production capacity is around 400 electric motors per day, which will be ramped up gradually. There are currently around 100 employees involved in the production process, and by the end of the year that number will rise to over 130.

The electric revolution is officially in progress.

Source: TOGETHER.net – Volkswagen AG

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