This is a very unusual strategy.
The BMW iX is not the German automaker's first fully electric SUV: that would be the iX3. But whereas the iX3 is based on the combustion-powered X3 SUV and will not be sold in the US, the new iX flagship is a global model built on a new bespoke platform designed from the ground up, just like the i3. It's a stark contrast to other BMW models, which are built on either the FAAR or CLAR platforms. These platforms are fully scalable, meaning they can accommodate electric and combustion powertrains.
Whereas the i3 uses a carbon fiber monocoque, the BMW iX's structural platform features an aluminum space frame and a "carbon cage" to reduce weight. As well as reducing weight, the bespoke platform offers other advantages. The iX is around the same length as the X5, but has a 0.9-inch longer wheelbase and more interior space.
Carbon fiber also features extensively, so it's stiffer than other BMW chassis and offers better stability. As this is a bespoke EV platform that doesn't need to be adapted for a combustion engine, there's room for a larger battery pack: the iX packs a 100-kWh battery providing an electric driving range of over 370 miles on the WLTP cycle, which will be around 300 miles rated by the EPA. For comparison, the iX3 utilizes an 80-kWh battery pack offering a WLTP range of up to 285 miles.
Unusually, however, Germany's Sport Auto reports that the BMW iX will be the only model that will use this new sophisticated architecture.
BMW has clearly made substantial investments to develop the platform, and yet no other model will utilize it in the future. Some components such as the electric drivetrain will be shared, however, but they're not unique to the iX. This suggests BMW was originally planning to build bespoke platforms for its EVs, but all future models will now be built on one of two scalable platforms designed to accommodate electric and combustion powertrains. It's a risky strategy, so we can only hope the BMW iX is a monumental sales success to make up for the steep development costs.