Audi tells us that with the e-tron, it is making electric mobility a reality for long-distance driving – thanks in part to charging power that is claimed to be unique among the competition. Audi says that the e-tron is not only the first mass-produced car that can be charged with up to 150 kW of electricity at a fast charging terminal (this is not a practical option in the UK at the moment), but the high charging power over a large portion of the charging procedure sets a benchmark and shortens downtime.
Convincing: the charging curve
The 150 kW charging curve of the Audi e-tron is characterized by continuity at a high level. Under ideal conditions, the car charges from 5 percent to 70 percent at the threshold of the maximum power before intelligent battery management lowers the current levels in order to protect the lithium-ion cells and guarantee the life cycle. A major difference from other concepts, which normally only reach their full power for a short time (peak) and lower their power considerably before reaching the 70 percent threshold. This is because the Audi e-tron continues charging at over 100 kW when it reaches 80 percent.
On a day-to-day basis, Audi says that this means an elementary benefit: For a range of around 100 kilometers, the customer ideally spends less than 10 minutes at the charging terminal. The Audi e-tron reaches the 80 percent mark after just under 30 minutes. Even though it takes much longer for technical reasons, to fill the remaining 20 percent of a lithium-ion battery, fully charging the Audi e-tron at a HPC terminal apparently takes less than 50 minutes.
Clever: the thermal management
The core of the cooling system is made up of extruded profiles – visually comparable with a slatted frame – which have been affixed to the battery system from below. A newly developed, thermally conductive adhesive joins the cooling unit to the battery housing. The gap filler forms the contact between the housing and the cell modules placed in it. This filler is a thermally conductive gel that fills the space to the housing beneath every cell module. In what is described as a particularly efficient solution, the gel evenly transfers the waste heat produced by the cells to the coolant via the battery housing. The spatial separation of elements and battery cells carrying cooling water also increases the overall system’s safety.