With its promising specifications, the BMW i4 is shaping up to be a serious threat to the Tesla Model 3. However, the i4 is just part of BMW's upcoming EV onslaught. So far, BMW has confirmed the iNext and iX3 electric SUVs will be joining the lineup.

But thanks to these new spy shots, we now know that BMW is also preparing a fully electric version of the 7 Series to fight the Mercedes EQS, which will essentially be an electric S-Class. What we don't know, however, is whether the production version will use the same body as the prototype seen here for the first time or if this a test mule being used to develop the technology.

How do we know this is a fully electric BMW 7 Series? The "electric test vehicle" sticker on the side is an obvious giveaway. At first glance, the prototype looks like a regular 7 Series, but the headlights and rear lights are covered with camouflage. This suggests the graphics could change to differentiate the i7 from the regular 7 Series. The i7 is expected to form part of the next-generation BMW 7 Series lineup, which will also include a regular combustion model and a plug-in hybrid.

According to reports, the entry-level i7 will be offered with an 80 kWh battery pack to match the i4, while the range-topping version could have a capacity higher than 120 kWh.

With its largest battery pack, the electric 7 Series could potentially travel 435 miles on a single charge. Rumors also suggest there will be two variants: an i7 and i7S, with the range-topping model rumored to produce over 650 horsepower. This would make it one of the most powerful BMW models yet. The next-generation BMW 7 Series is expected to arrive in late 2021 or early 2022, so the i7 isn't likely to debut until 2022 at the earliest.