BMW i4

The BMW i4 (model code G26) is a battery electric compact executive car produced by BMW since 2021. It has a five-door liftback body style and is marketed as a four-door coupé. The initial concept version, named BMW i Vision Dynamics, debuted at the 2017 Frankfurt Motor Show. It is the fifth BMW i sub-brand model, and is sold in several variants at different performance levels, including the first battery-electric variant by BMW's motorsport division. The production version was revealed in March 2021 and went on sale in November of the same year as a 2022 model.

An investment of about €200 million in the Munich plant was made in preparation for the 2021 series production as the G26 BMW i4 is built on the same assembly line as cars with combustion engines and plug-in hybrids. While 90% of the existing production equipment in the body shop were incorporated into the production process of the i4, several new systems were required mainly for the floor assembly and rear structure as the electric drive and high-voltage battery are different from conventional architectures. The plant was closed for six weeks in the summer of 2020 to convert more than 1000 robots in the body shop and assembly area to prepare it for the assembly of the i4. The electric motor is assembled in Dingolfing. The i4 was revealed fully production-ready in March 2021, three months ahead of schedule, and went on sale in November 2021.

Over an ownership period of 200,000 km (125,000 mi), BMW stated at launch that the eDrive40 has a 45 percent lower global warming potential than that of a comparable diesel G20 3 Series or G22 4 Series model. Furthermore, BMW enhanced the sustainability of its supply chain and increased its use of recycled materials for the i4, cutting the production emissions by 18 percent.

The production model is based on the modular CLAR platform to keep costs low and volume-production attainable. Although it is described as a battery-powered G20 3 Series, the model uses the bodyshell design of the G26 4 Series Gran Coupé. The i4 has a MacPherson strut front suspension and multi-link rear suspension with rear air suspension as standard (the M50 adds adaptive M dampers). It has a damping system designed to reduce “dipping movements of the body” under acceleration or braking, with an “actuator-related wheel slip limitation” system to better boost traction and stability.

The i4 has an almost completely flat underbody, resulting in a low drag coefficient of 0.24 for the eDrive40 and 0.25 for the M50. Compared to the G20 3 Series, it has 26 mm (1.0 in) wider front tracks and 13 mm (0.5 in) wider rear tracks. Due to the low floor location of the battery pack for better agility, the M50's center of gravity is 34 mm (1.3 in) lower than the G20 3 Series and 53 mm (2.1 in) lower in the eDrive40. An active air flap control at the bottom of the grille can be adjusted in ten stages, allowing cooling air to be supplied to the drive system, battery, brakes, and air conditioning system in precise quantities. The eDrive40 has a 45:55 weight distribution, while it is 48:52 for the M50.

The electric drive component of the i4, its charging unit and high-voltage battery are all developed in-house by the BMW Group, forming the fifth-generation eDrive system. A notable technical feature of the i4's powertrain concerns its packaging. The electric motor, transmission and power electronics are all contained in a single component, which allows for a higher efficiency of energy conversion. BMW also focused on reducing the number of rare earth materials in the battery and electric motor system. None are used to construct the motor (efficiency factor of 93 percent), while the battery uses two thirds less cobalt than before. The motors themselves are positioned in the axles, and the axles also house the one-speed transmissions.

The M50 can recuperate braking energy at a max rate of 195 kW and 116 kW for the eDrive40. The three adjustable regenerative braking levels includes a robust setting for one-pedal driving, while the fourth adaptive mode uses GPS data and driver-assistance systems to adjust the amount of regenerative braking. The eDrive40 is a rear-wheel drive model, where power comes from a single 250 kW (340 PS; 335 hp) electrically excited synchronous motor that is fitted to the rear axle. The M50 runs predominantly in rear-wheel drive mode, conserving energy and thus increasing range. The larger 230 kW (313 PS; 308 hp) electric motor resides at the rear, while the smaller 190 kW (258 PS; 255 hp) only kicks in when the front tires require power. Using a pre-warmed battery, consumption can be 20 kWh/100 km driving in winter mountains.

The 108 mm (4.3 in) tall battery in the i4 is made up of four modules with 72 cells each and three 12-cell modules, all are located in the floorpan in a process that's claimed to add rigidity to the overall structure. The battery enclosure is directly connected to the front axle subframe, while the battery pack is bolted to the floor assembly with 22 bolts. There is also an additional section of the battery housed within the center tunnel, usually occupied by a driveshaft. The battery voltage is between 400 volt (empty) and 477 volt (full), with a nominal voltage of 430 volt. The i4's battery has 40 percent more energy density than the 120 Ah version of the BMW i3.