Audi just released more details on the upcoming 95 kilowatt-hour Audi e-tron battery and its looking remarkably similar to the design of the Jaguar I-PACE pack. Aside from the capitalization of the vehicle names, what’s different and what’s similar?
Both packs contain 36 aluminum “shoebox” modules containing 12 “pouch” cells each for a total of 432 cells. Although Audi didn’t specifically say so, there is little doubt that both cars use 4 cells in parallel in a group for a total of 108 cell groups. Most previous electric cars tended use around 96 cell groups.
These 108 cell groups are strung together in series which effectively adds up their voltage into a full nominal pack voltage of around 390V since each cell group has a nominal voltage of about 3.6 volts. Battery voltages slump down when near empty and rise up when near full. A fully charged pack with 108 cell groups is likely going to be around 450 volts (Jaguar’s tops up at just under 450V).
The individual cells appear to be physically similar. Audi says their cells hold 60 Ah (a measure of energy holding capacity) vs the Jaguar’s 58 Ah which accounts for the overall capacity difference of “95” kWh vs “90 kWh” between the cars. The energy capacity of cells can be measured in different ways so its hard to know exactly what 60 Ah or 95 kWh means unless you know under what conditions it has been measured. Neither Audi or Jaguar has not released that level of detail.
Using that energy, the e-tron has a WLTP estimate of 249 miles. WLTP is the new European test cycle that replaces the less realistic NEDC which Audi previous used to estimate an e-tron range of about 310 miles. Jaguar says the I-PACE has a WLTP of 298 miles but has only an estimated EPA range of near 240 miles. The Chevrolet Bolt EV has a WLTP range of 236 miles and an EPA range of 238. Jaguar’s 298 mile WLTP estimate seems oddly high.
We know that Korean conglomerate LG is making the I-PACE cells (as well as for the Chevrolet Bolt EV). Recent rumors have said that Audi is using either LG or Samsung SDI cells.
One difference that stands out is charging speed. Audi claims to charge noticeably faster from 0 to 80 percent in 30 minutes vs 0-80 percent in 40 to 45 minutes in the I-PACE. Audi seems to be saying that the e-tron can actually charge at a peak rate of about 150 kW. This is plausible due to the higher than usual battery pack voltage levels and because some “150 kW” chargers like the ABB Terra HP can output up to 375A. The I-PACE has a peak charging rate of close to 100 kW during the first 15 minutes of charging.
Audi’s VW group peer, Porsche, has claimed their Mission E car being brought to production in late 2019 will charge from 0 to 80 percent in 15 to 20 minutes. Porsche says their battery can charge so fast that they need to double the charging voltage up to around 800-volts. This implies that the Audi cells may be different from the ones being used by Jaguar.
See also: How does 800V charging work?
Another similarity between the packs is the thermal management. Both designs use a water-based liquid coolant (essentially identical to what is used in an internal combustion engine) and circulate it under the aluminum housing tray that holds the battery modules.
Although not shown in the illustration above, there is likely a thermal transfer pad between the modules and the housing tray like there is in the I-PACE.
After Elon Musk publicly announced that Tesla was open to allowing access to its Supercharger network under the right deal there were various rumors about whether this or that traditional auto maker was negotiating a deal with them. That speculation included Jaguar.
Although there may be business reasons to forego a deal with Tesla there is also a technical conflict. Both the I-PACE and e-tron packs reach about 450 volts when full but at least some of the Tesla Superchargers can only output up to 410 volts because that’s all Tesla’s packs have needed so far.
See also: Jaguar and Chevy have LG in common