What the Tech: How does the charging tech­nology of e-cars work?

Alter­nating current charging columns are mainly found at private wall­boxes and are connected to the low-voltage grid. These operate with outputs of approx. 3.7 to 22 kW, whereby the charging output of 11 kW has estab­lished itself as the unspoken stan­dard. Depending on the power and battery size of the e-cars, charging times vary between about 16 and two and a half hours.

If you’re on the road with the e-car, of course, it has to be faster. Direct current charging stations are fast-charging stations that operate with powers from 50 kW up to 350 kW. As a result, the average charging power of e-cars is also shorter. On the other hand, the public charging stations are connected to the medium- or high-voltage grid, for which new power lines have to be laid. This costs time and, above all, money. When elec­tricity is stored and used, heat is gener­ated at all parts, which of course has to be dissi­pated effi­ciently.

Usually, the inte­rior of the fast charging station, the power elec­tronics and the cooling circuits are cooled with air. Partic­u­larly powerful charging cables are cooled by pump-driven cooling circuits. Outdoor suit­ability is partic­u­larly impor­tant for this. Even under harsh envi­ron­mental condi­tions, the reli­able func­tioning of the fans and venti­la­tors in the fast charging stations must be guar­an­teed.

This is why they are tested in shock, vibra­tion and corro­sion tests, as well as in Highly Accel­er­ated Life Tests, the Temper­a­ture Change Control Test and in tests for elec­tro­mag­netic compat­i­bility. In addi­tion, all the fans and venti­la­tors of the fast charging station have elec­trical over­voltage protec­tion.