Fast charging: This is how turbochargers for electric cars work
Fast charging is an important decision criterion for e-car buyers. The reason is clear: If you don’t just drive around town, but also go on the road, you don’t want to spend long breaks charging.
The goal: 80 percent charge in less than 20 minutes
Fast charging starts at 50 kilowatts (kW) and now reaches up to 350 kW. From 150 kW one speaks of High Power Charging (HPC) or ultra fast charging. With a quick power tap, it only takes a few minutes to fill up the battery for a range of 100 kilometers. The target time is a full charge from 10 to 80 percent (state of charge/SOC) in less than 20 minutes.
What current flows during e-car fast charging?
In contrast to normal charging, only direct current (DC = Direct Current) flows during fast charging. DC charging stations convert the alternating current (AC = Alternating Current) from the power grid itself into direct current (DC). This bypasses the mains converter in the car, the DC juice goes directly to the car battery. CCS or CHAdeMo (or Tesla Supercharger) are required as plug types.
In addition to the performance of the charging stations, weather conditions and charging capacity, i.e. the battery management of electric vehicles, are also extremely important. For example, if the traction battery is not at its comfortable temperature in the cold winter, the current will flow more slowly than in the summer, even with fast charging.
In this context, an outside temperature of 20 to 30 degrees Celsius is considered optimal. With some vehicles it is possible to automatically preheat the battery when a fast charging station is selected as the destination in the navigation system.
Can fast charging harm electric cars?
The charging speed is not the same during the entire charging process, but decreases as the level increases in order to protect the battery – because fast charging also places a special strain on the material due to the high charging current.
After a while, very high temperatures develop in the battery, which can lead to accumulation of metallic lithium on the anode. This shortens the life of the battery. In general, it is advisable to charge an e-car that can be charged quickly, if possible, slowly and thus more gently.
Fast charging parks mostly on motorways
Tesla Supercharger with a special role
Tesla has a special role to play here. With its superchargers, the US manufacturer is a pioneer in the creation of innovative and fast charging options. However, these are mainly reserved for Model S, Model X, Model 3 and Model Y. Electric cars from other brands can only use superchargers at 16 locations.
Apps help with navigation and payment
For example, the web-based app “Schnellladepark” helps when looking for express charging stations. Almost 800 charging parks with at least three filling points are listed there.
Free apps like “Plugsurfing”, “Next Plug”, “NextCharge” or “Chargemap” also help. You navigate to the next fast charger and show prices and payment options. The cost per kilowatt hour is between 40 and 80 cents. The turbo columns are usually started and paid for using charging cards or smartphones.