|AC Propulsion Drive System for MINI E. Click to enlarge.|
AC Propulsion is supplying both the electric propulsion and the battery technology for the MINI E electric vehicle introduced at the 2008 Los Angeles Auto Show by BMW Group. (Earlier post.) AC Propulsion has already delivered more than 500 drive systems to the BMW Group factory in Munich for MINI E production.
The MINI E features a 150 kW (204 hp) electric motor powered by a 35 kWh lithium-ion battery pack (approximately 28 kWh usable), with a single-stage helical gearbox transferring power to the front wheels. The electric drive train produces a peak torque of 220 Nm (162 lb-ft), with 0 to 100 kph acceleration in 8.5 seconds. Top speed is electronically limited to 152 kph (95 mph).
|MINI E on the road. Click to enlarge.|
BMW puts consumption for the MINI E at 190 Wh/mile (120 Wh/km) under the US Federal Test Procedure (FTP), also referred to as UDDS (Urban Dynamometer Driving Schedule). The battery pack will support an approximate range of more than 240 km (150 miles).
The MINI E uses a specially-developed version of AC Propulsion’s proprietary tzero technology to provide high performance, high efficiency, and fast charging. AC Propulsion’s air-cooled copper-rotor induction motor produces maximum torque from zero to 5,000 rpm and spins all the way up to 13,000 rpm. The IGBT inverter drives the motor to produce its peak power of 150 kW. Continuous power is 50 kW.
AC Propulsion also supplies the battery pack for the MINI E. The 35 kWh, 380V pack comprises 48 Li-ion modules, each assembled from 106 small Li-ion cells (5,088 cells in total) using proprietary assembly techniques and battery management technology. Each module sends voltage and temperature information to the management system which controls for optimal battery operation under driving and charging conditions. Battery data are logged to provide information for analysis and evaluation.
The 48 modules are packaged into three battery elements that are compactly arranged inside the MINI E. The 260 kg (573 lb) battery pack extends rearward from the heel plate and replaces the rear seat bench. A temperature-controlled fan ensures a constant operating temperature. A shared high-voltage connection supplies the electric motor with energy from the three battery units.
|View of the battery pack from the rear. Click to enlarge.||Lower front of the battery pack. Click to enlarge.|
AC Propulsion’s patented battery charger is an integral part of the AC Propulsion drive system used in the MINI E. When the wallbox outlet is connected to the charge port on the MINI E, charging proceeds automatically.
The tzero technology includes patented control and construction techniques that allow the power electronics and motor windings to be re-configured as a high-rate Reductive battery charger. By using existing componentry, the Reductive Charger reduces vehicle cost and weight. By allowing safe charging from existing 110V to 240V outlets at rates from 200 W up to 20 kW (with a 240V line), the Reductive Charger reduces infrastructure installation requirements and costs, and a bi-directional power capability allows self contained vehicle battery diagnostics and standby power generation.
Estimated charge times are 23.6 hours at 110V/12A (1.3 kW); 4.4 hours at 240V/32A (7.0 kW); and 2.9 hours at 240V/48A (10.6 kW). The bi-directional charger can serve as a regulated power source with many possible applications including, battery pack self-diagnosis, back-up power, car-to-car charging, and, perhaps most importantly in the future, providing ancillary services to the power grid (vehicle-to-grid, V2G).
AC Propulsion is working with V2G research and development programs throughout the US to supply V2G-capable vehicles, evaluate V2G functionality, and develop the communications and control systems that will necessary to enable electric vehicles to support the power grid.
AC Propulsion was founded in 1992 by Alan Cocconi. It has headquarters, engineering, manufacturing, and test facilities in San Dimas, CA (Los Angeles County), and operates a wholly-owned manufacturing plant in Shanghai PRC. Total employment is over 100 persons and production capacity is more than 2,000 drive systems per year.
AC Propulsion is the owner of 6 issued patents on EV technology, which have been licensed to other companies, including Tesla Motors. Some of this technology was originally developed by AC Propulsion for its tzero electric sports car which achieved 0-60 mph acceleration in 3.6 seconds and 300 mile range while driving 60 mph.