Understanding the Reality of DC Charging Peak Power for Electric Vehicles

150 kW, 200 kW, 250 kW – the competition for peak power in DC charging continues to escalate. However, is the significance of a vehicle's maximum charging power overstated? In reality, DC charging represents a small fraction of an electric car's overall charging sessions. For instance, 95% of European drivers travel less than 50 km daily. Consequently, how critical is the rapid restoration of a minimal charge?

The rise of DC charging's profile stems from manufacturers showcasing advancements in battery technology. Many consumers still compare the "charging power" and refill times of electric vehicles (EVs) to those of internal combustion engine (ICE) vehicles.

While DC charging is undoubtedly important for long road trips, do vehicles capable of 200 kW, 250 kW, or even 300 kW truly deliver on their promises? Let’s investigate further.

Peak Charging Power

Peak charging power is one critical factor to consider. Recent innovations in 800V architecture have introduced models such as the Lucid Air (300 kW) and the Porsche Taycan and Audi e-tron GT (both 270 kW).

In the 400V landscape, Tesla leads with a peak charging power of 250 kW via its V3 superchargers. Conversely, vehicles with lower charging rates include those with air-cooled batteries, like the Nissan Leaf (50 kW) and the Skoda Citigo and VW e-up! (40 kW).

The table below summarizes the peak charging rates and estimated range achieved per minute of charging at peak power, calculated using expected electricity consumption at 130 km/h on the highway, a scenario in which DC charging is often imperative.

The Charging Curve

While peak DC charging power is indeed significant and reflects the technological capabilities of an electric vehicle, the average driver tends to value the mean DC charging power from 10% to 80% state of charge more.

Ideally, peak DC charging power would align with charging durations, but this is not the case in practice. High-voltage batteries can only sustain peak power for limited periods, usually at specific charge levels.

Charging curves vary by model, primarily dependent on battery specifications and the management of charging by the Battery Management System (BMS). Reductions in charging power serve as safety measures to prevent excessive heating, while higher charge levels necessitate cell balancing, which caps charging power.

In the following table, we present real-world data reflecting mean charging power from 10% to 80% and the corresponding range per minute of charging. Interestingly, the top-performing models demonstrate average DC charging power peaking around 175-180 kW, despite significantly higher peak DC charging power ratings. This data is derived from charging curves shared by Fastned.

Conclusions

Ultimately, regardless of the maximum charging power a car can initially accommodate, most models appear to plateau at a mean charging power of approximately 180 kW during typical DC charging sessions up to 80%. This conclusion aligns well with current technology.

Presently, the majority of electric vehicles utilize Li-Ion NMC chemistry batteries, leading to minimal variation among them. This 180 kW mean charging power threshold seems to be independent of voltage (400 or 800V), suggesting it may represent the technological limit for existing chemistries. Future advancements, possibly involving Li-Air or solid-state batteries, may one day enhance this limit. Only time will tell.