Fast charging: A question of data

400 more kilometres of range in 15 minutes. Ultra-fast charging stations are designed to significantly improve the everyday practicality of using electric cars. To safely achieve high-voltage charging using direct current requires not only energy but also the streaming of a large amount of information and data.

Is the battery half empty or half full? The answer depends on your attitude. What is certain, however, is that "range anxiety" has so far been one of the most important reasons why new registrations of electric cars are still in the low single numbers. The decisive factor for range, in addition to battery size, is the time required for sufficient recharging. Whether this is 20 minutes, 40 minutes or several hours for longer journeys depends on battery capacity, the car's on-board charger (for alternating current), as well as the available infrastructure. The options for electric refuelling start with a normal household socket with an output of 3.6 kilowatts. An installed wallbox generates 11 kilowatts, double this is available at the supermarket carpark's charging station, and quick charging stations reach 150 kilowatts. Against this background, the planned ultra-fast charging stations with 350 kilowatts and more power, which are to be built in Germany and Europe by the end of 2019, are particularly impressive. For comparison: The power of three ultra-fast charging stations corresponds to the power of a medium sized production plant. An initial test installation has recently been put into operation on the A61. High-voltage charging should make it possible to recharge in just 15 minutes enough electricity for 400 more kilometres. Electromobility is thus becoming significantly more attractive. But this requires energy transfer that is safe, efficient and fast.

Therefore, not only does the power need to be increased, i.e. the amount of electrons transferred, but also the amount of data exchanged between charging station, cable and vehicle battery. Lots of varying information needs to be transmitted bi-directionally, checked, monitored and permanently evaluated in very short times during a single charging procedure. The success of fast loading depends in particular on these data streams being managed securely and accurately. For example, the power electronics at each individual charging point must ensure that the right charging algorithm is applied that is optimal for the charge curve of the installed battery. Only then can energy be refuelled safely, quickly and, above all, without damaging the battery. And those with experience of quick charging already knows that at the end of the charging process, the output is reduced so that the speed of charging noticeably decreases. This is because batteries are unable to absorb as fast the final electrons. Damage to the battery would otherwise occur with significant and adverse impacts on battery service life and overall performance. Another factor concerns temperatures in the components involved in the process, especially in the charging cable. When direct current is transferred from the charging station via the cable to the vehicle battery, heat is generated in all electrical components and so overheating needs to be avoided.

The charging cables with integrated cooling developed by LEONI on the basis of LEONiQ's new key technology withstand the high loads of high-voltage charging thereby remaining user-friendly and low-risk. Thanks to LEONIQ's innovative key technology, sensor and electronic elements can be used digitally to ensure that vital information is continuously recorded during the charging process and evaluated almost in real time. Vehicle batteries can therefore be charged faster and more efficiently because potential faults,such as overheating of the charging cable and, in future, damage to the battery system, can be detected at an early stage. LEONIQ uses in part IoT solutions developed by Microsoft, such as MS Azure Sphere. These enable data to be pre-sorted in the intelligent cable and then securely transferred to the cloud. LEONiQ then makes this data directly accessible to customers on a dashboard, instantly and regardless of location. The generated data enables the system to become better and better because future designs can be optimised using actual field data.  High-voltage charging cycles can then be monitored and improved. The integrated cloud solution enables initial preliminary analyses to be carried out within the connected system. These are then sent to operators and users and interpreted further by algorithms specially developed by LEONI, and then converted into correspondingly practical information. Thanks to LEONiQ, interaction between all components of the digital ecosystem makes every high-voltage charging process safer and more transparent, with the aim of protecting the vehicle's battery system from short or long-term impairment or damage caused by the charging process, and ensuring that electric mobility continues to be successful.

Visitors to computex in Taiwan were able to get a lasting impression at a joint trade fair stand with Microsoft, where LEONiQ exhibited in conjunction with MS Azure Cloud.