Inside Audi e-tron’s Battery

(Image: Audi)

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.