Safe charging with direct current

Safe charging with direct current

The largest charging station for electric vehicles is currently being built in Zusmarshausen near Augsburg (Germany). A visionary project that could solve the challenges posed by the mobility of the future. LAPP has developed a special DC cable for the innovative project, which can also be used to provide greater output in the short term.

 

 

The Sortimo Innovationspark Zusmarshausen is located directly by the A 8 motorway between Munich and Stuttgart. The innovation park has over 144 charging points, of which 24 are earmarked as "fast-chargers" with a power output of up to 420 kilowatts (kW). The site is planned as a DC energy hub that is intended to provide current and power to electric vehicles as quickly and efficiently as possible – and use current and power that is primarily generated locally to do so. There are currently no vehicles that use the amount of power that the fast-chargers provide – that's still a way off. For all other electric vehicles already on our roads, there are 120 additional DC fast-chargers. With 140 kW in the first stage of development, they already exceed the common market standards for battery charging: it takes about 45 minutes.

"Germans need to be much braver when it comes to investing in new technologies. With the increased support of electric vehicles in Germany, I hope that electric mobility will finally be encouraged and sped up as an important part of the energy revolution," says Frank Steinbacher, Managing Director and shareholder of eLoaded GmbH and Steinbacher-Consult. He is a source of ideas for and planner of the Sortimo Innovationspark Zusmarshausen. Sortimo Innovationspark Zusmarshausen GmbH in Zusmarshausen is the building developer and investor; it is the market leader for vehicle equipment and mobile transport solutions.

"Up to 4,000 cars can be charged at our site every day," expects Steinbacher: "This corresponds to an annual mileage of over 400 million kilometres." However, this is only the first step: thanks to its modular design and power supply concept, this system can be upgraded to 280 kW without having to make any further changes to the infrastructure. New technical solutions allow the design for a 140-kW charging point to be shrunk to the size of a current slow-charger with an output of 22 kW. Sortimo Innovationspark Zusmarshausen is due to be put into operation at the end of 2020. But that's not all: in addition to the restaurant, café, small shops and offices in the first phase of construction, there is still room for businesses interested in the field of electricity and centres for research and innovation. Everyone should be able to make the best possible use of their time during charging; you can even take a short walk in the rewilded area of meadows surrounding the river Roth. "All or nothing" is the motto of the Sortimo Managing Director Klaus Emler. In the first step, the company is investing tens of millions of euros into the project. Further development of the area also depends on developments in the field of electric mobility in the future.

For Sortimo, the investment could soon pay off. It will use the charging park for its own fleet and its customers' fleet, including public transport. This year, the first express e-bus route between Zusmarshausen and the city of Augsburg will be launched. Charging of the vehicles during deployment is dynamically adapted depending on up-to-date information on renewable energy being generated in the region. Operators therefore do not need a depot and can do away with costly charging during the night. The charging park is also available for private transport.

It goes without saying that, at Sortimo, renewable electricity is used for charging – primarily from a photovoltaic unit in the region. Additional electricity is sourced from hydropower if required. The special feature at the site is that energy distribution is carried out via a DC supply network. Frank Steinbacher brought LAPP on board when it came to direct current. The global market leader in integrated connection systems is a pioneer in direct current. LAPP has developed a special DC cable for the innovative project, which can also be used to provide greater output in the short term and which enables heat development in the cable to be controlled at the same time. LAPP has developed the complete DC bus for connecting charging stations for this, including hybrid DC cables for control and online monitoring. The cable design is very sophisticated: the cable (which was specially designed for the charging park) consists of an aluminium conductor with a 30-mm2 cross-section. The core insulation is cross-linked and consists of polyethylene. Shielding is achieved using copper wires applied over the core in spirals. The special feature of this product is that the design is supplemented by two stainless steel tubes, each with six fibre optic cables. These are used for measuring the temperature and trigger an alarm if the temperature at the charging points becomes too high. The bus is then used to control where, alternatively, free charging capacity is available. The outer sheath is made of PVC according to IEC 60502. "LAPP is not only a partner with a regional presence – it is also big enough to provide everything we need. Thanks to its global positioning and the desire to always be a leader in innovation, we can definitely continue to grow with LAPP," explains Steinbacher. The use of direct current plays a central role in Frank Steinbacher's projects. "We no longer want to think about things in terms of AC, but rather in terms of DC. With this switchover, we can achieve savings of 20–25 per cent in terms of energy efficiency," says Steinbacher. The reason for this is that photovoltaic systems and wind turbines only generate DC. With direct current, the losses that occur during the conversion between alternating current (AC) and direct current (DC) and vice versa are eliminated. An energy grid systematically configured to direct current would achieve an overall efficiency of 90 per cent – compared to 56 per cent today.

In the Sortimo Innovationspark Zusmarshausen, the energy distribution is precisely tailored to the charging operation. However, the sophisticated energy management system doesn't just bear in mind the charging processes, but also the production directly connected to this – this is the only way to achieve cost-efficient operation that reconciles the amount of electricity and output. Frank Steinbacher focusses on reducing operating costs and multifunctional use of the infrastructure. Steinbacher is convinced that "whoever can use energy and the associated infrastructure with the greatest possible versatility and flexibility will achieve significant financial benefits compared to standalone solutions. If the full capacity of the Sortimo Innovationspark Zusmarshausen is used, this saves around 30 million litres of fuel and 60,000 tons of carbon dioxide (CO2) per year solely by replacing modes of transport that use fossil fuels. In terms of direct current, LAPP is active in the development of cables and already has a range of cables for an extremely wide variety of applications. These include the Ölflex DC 100 with new colour coding of the cores according to the standard DIN EN 60445 (VDE 0197):2018-02 for DC cables: red, white and green-yellow, updated in 2018. Other cables are the Ölflex DC Servo 700 for stationary applications and the Ölflex DC Chain 800 made from TPE for mobile applications. Or the first DC robot cable Ölflex DC Robot 900 with core insulation made from TPE and a sheath made from PUR. This makes LAPP a pioneer in the development of cables for low-voltage DC networks for industrial applications. At the same time, LAPP is a sponsored partner of the DC-Industrie2 research project and researches the long-term stability of insulation materials for cables. This is because LAPP and TU Ilmenau discovered in tests that insulation materials in the field of direct current age differently than in the field of alternating voltage. "We see great economic opportunities in direct current, and not just for the automotive and process industries. Many consumers are already direct current consumers. Reducing conversion losses increases efficiency and due to the elimination of converters, we need fewer components and therefore less space. Renewable and decentralised energy sources can be integrated more easily. Kinetic energy is also fed back via DC. The electric motor becomes a generator," Guido Ege, Head of Product Management and Product Development at U.I. LAPP GmbH, lists the advantages