Inside Audi e-tron’s Battery
For electric vehicles, quick charging time is an essential characteristic. According to Audi, one thing that has to be taken into account is that a high charging speed (i.e., kWh/minute) isn’t something that should be considered in the context of something that occurs during a limited period of the high power charging (HPC) cycle, but for a longer duration. The lithium-ion battery in the e-tron has a gross capacity of 95 kWh (net: 86.5 kWh). When it is plugged in to an HPC terminal with 150 kW output, it is capable of taking on charge at a higher level for a longer period of time (it can reach 80% of charge in approximately 30 minutes) because of the thermal management system.
The e-tron battery has liquid cooling so that the battery temperature stays within an optimum range of 77° to 95°F. During direct current charging the battery heats as a result of electrical resistance that builds in the battery. So the thermal management system needs to deal with it.
There are 5.8 gallons of coolant that circulate within 131 feet of cooling lines that are organized into four coolant circuits. There is a series of extruded profiles that are attached to the bottom of the battery housing with a thermally conductive adhesive. It is worth noting that the coolant system is separate from the battery itself so if there is any coolant leakage, it doesn’t go into the battery. There is also a thermally conductive gel between the housing and the battery cell.
Lithium-ion batteries have become the technology of choice for EVs, and falling costs and rising energy levels could keep them on top for nearly two decades.
A young(ish) guy that I’ve known for a number of years, a man who spent the better part of his career writing for auto buff books and who is a car racer on the side, mentioned to me that his wife has a used Lexus ES Hybrid.
Generally, when OEMs produce aluminum engine blocks (aluminum rather than cast iron because cast iron weighs like cast iron), they insert sleeves into the piston bores—cast iron sleeves.