A series of photographs released by BMW to its global media website reveal a lightly disguised prototype of its upcoming i4 electric sedan undergoing cold weather testing alongside the German car maker’s new iX3 and iNext SUVs.

BMW says the testing, taking place at its cold weather testing facility near Arjeplog in northern Sweden, aims to determine the durability of the lithium-ion batteries, electric motors and suspension systems used by its three new electric-powered i-brand models prior to their launch in the early part of next decade.

The iX3, based on the latest X3, will be the first to arrive of the new BMW models to arrive in 2020, followed a year later by the standalone iNext and the 4-series-based i4 - the latter of which was originally previewed by the i Vision Dynamics at the 2017 Frankfurt motor show.

The Tesla Model 3-rivalling four-door i4 is claimed to boast a range of over 600km, a 0-100km/h time of 4.0sec and a top speed of more than 200km/h, according to figures quoted by BMW.

Although it wears disguise, a clear visual link between the i4 prototype and the latest 3-series is evident. The i4 will share much of its design with the upcoming second-generation 4-series, including elements of its CLAR platform structure.

However, a side-on view reveals that the new car appears higher off the ground (both in terms of roof height and ground clearance) than today's 4-series, suggesting a raised floor to accommodate a sizeable long-range battery. Other tell-tale signs that this is the i4 include a blanked-off front grille, fake 'exhausts' in the disguise and legally mandated 'electric test vehicle' stickers.

The i4 is scheduled to be built on the same line as standard 3-series models at BMW's factory in Munich, Germany. To ensure a smooth production process with existing petrol, diesel and hybrid models, the manufacturer is already running assembly tests with pre-production versions.

The iX3 and iNext are set to be produced at BMW’s Chinese joint venture partner Brilliance in Shenyang, China and at BMW’s own Dingolfing factory in Germany respectively.

The expansion of the BMW i divison sub-brand follows a ruling by the EU to enforce a fleet average CO2 emission reduction of 35% by 2030. The ruling effectively spells an end to the combustion engine as a sole source of propulsion for high-volume cars sold in Europe by the end of the next decade.

This was expected by BMW’s top management, who initiated an acceleration in the development of both long-range plug-in hybrids and pure electric models in a board meeting held earlier this year.

Speaking at last year’s Paris motor show, BMW chairman Harald Krüger confirmed the altered i division plan, which aims to enable BMW to offer more electric cars than any rival premium brand in the short term.

It calls for the introduction of up to five dedicated i models by the end of 2021, with tentative steps to expand to 12 electric models within the whole BMW Group, including Mini and Rolls-Royce, by 2025.

Krüger has also given the green light for 25 new plug-in hybrid models to be introduced by 2025 in order to meet the strict 2030 CO2 target.

Among the models at the centre of BMW’s electrification strategy are a further developed version of the continuously evolving i3, the Mini SE, the iX3 and the i4. BMW will follow that with a more advanced range of premium electric cars employing solid-state batteries and autonomous driving features, previewed on the iNext concept car.

Talking about the i4, Krüger said: “The leading factors that will set it apart are fantastic design, which is very different to anything else on the road, and the fact that it is lighter and therefore more dynamic than anything we see on the market today, thanks to the materials we will use. Couple that with the connectivity technology we are constantly developing and we are confident it will lead the market.”

BMW says the i4 will receive a fifth-generation e-Drive technology. It claims the electric motor’s “spontaneous power development” provides it with a “dynamic driving” traits.