As 2012 comes to an end, BMW is celebrating 40 years of electric vehicle development.
It all began at the 1972 Olympic Games in Munich, where BMW presented two test-vehicles: a pair of electrically-powered BMW 1602 models.
These two converted BMW 1602 models served as a means of transport for the members of the organizing committee and were also deployed either as support or as camera cars in various long-distance events.
The pair of 1602s were equipped with lead batteries weighing 350 kilograms and had a range of around 60 kilometers (37 miles). Certainly not ready for production car status!
BMW kept researching the technology. Starting in late 1975, an experimental vehicle built on the platform of the BMW LS and fitted with new batteries and a new electric motor started to deliver the first findings for BMW researchers.
Then, in the 1980s, a research project was launched entitled “Electric car with high-energy battery”, which provided experience in the use of sodium-sulfur energy storage devices.
In the midst of this project, BMW constructed a special test rig for electric drives with a built-in output calculator.
Besides the batteries, testing here focused primarily on the drive system and drive control. To trial the concept, eight vehicles based on the ‘80s BMW 325iX were converted and subsequently proved their merit in inner-city use, as delivery vehicles for the German postal service for example.
These 325iX converted to front-wheel-drive served as experimental vehicles for a brand-new, maintenance-free sodium-sulphur (NaS) battery, which had been purpose-developed by Asea Brown Boveri (ABB) for use in an electric vehicle.
These new batteries represented a great leap forward as they had an energy density three times greater than that of conventional lead-acid batteries.
Combined to the electric motor’s peak output of 22kw, these batteries gave the test vehicles a range of 150 km (93 miles).
It is the results of this series of tests that prompted BMW to start working on a pure electric vehicle, not merely adapting an existing design.
BMW quickly realized that the limited range of electric cars made them of interest for city use first and foremost. The first purpose-built solution was unveiled at the 1991 Frankfurt Motor Show: the BMW E1.
The E1 was an electrically propelled “citymobile” for use in cities. Even back then, this prototype stood out for its low weight and high safety levels thanks to its lightweight design and high-strength body shell.
It was also a first step towards a sustainable electric car, with an output of 32 kw, a peak torque of 111 pound-feet and a range of around 160 kilometers (100 miles).
In addition to the five E1 prototype vehicles, the project also featured 25 converted production models based on the BMW 3 Series.
Between 1992 and 1996, eight BMW 325 models were in service on the island of Rügen, off Germany’s Baltic coast, to test out various motors, transmissions and batteries in everyday conditions.
This field trial produced large quantities of detailed data, which provided valuable knowledge still used today for the development of BMW’s electric vehicles.
The next big step was taken in 2008 when a fleet of around 600 all-electric MINI E models designed for private, everyday use took to the roads, followed by over 1,000 units of the BMW Concept ActiveE in early 2010.
Together, and with the knowledge of electric vehicle research one over the last 40 years, the MINI E and Active E helped develop the electric drive system that will be found in the BMW i3, due to roll off the assembly line in Leipzig in late 2013.