The Mitsubishi i-MiEV (MiEV is an acronym for Mitsubishi innovative Electric Vehicle) is a five-door electric city car produced in the 2010s by Mitsubishi Motors, and is the electric version of the Mitsubishi i. Rebadged variants of the i-MiEV are also sold by PSA as the Peugeot iOn and Citroën C-Zero, mainly in Europe. The i-MiEV was the world's first modern highway-capable mass production electric car.
The i-MiEV was launched for fleet customers in Japan in July 2009, and on April 1, 2010, for the wider public. International sales to Asia, Australia and Europe started in 2010, with further markers in 2011 including Central and South America. Fleet and retail customer deliveries in the U.S. and Canada began in December 2011. The American-only version is larger than the Japanese version and has several additional features.
According to the manufacturer, the i-MiEV all-electric range is on the Japanese test cycle. The range for the 2012 model year American version is on the United States Environmental Protection Agency's (US EPA) cycle. In November 2011 the Mitsubishi i ranked first in EPA's 2012 Annual Fuel Economy Guide, and became the most fuel efficient EPA certified vehicle in the U.S. for all fuels ever, until it was surpassed by the Honda Fit EV in June 2012 and the BMW i3, Chevrolet Spark EV, Volkswagen e-Golf, and Fiat 500e in succeeding years.
, Japan ranked as the leading market with over 10,000 i-MiEVs sold, followed by Norway with more than 4,900 units, France with over 4,700 units, Germany with more than 2,400 units, all three European countries accounting for the three variants of the i-MiEV family sold in Europe; and the United States with over 1,800 i-MiEVs sold through August 2014. As of early March 2015, and accounting for all variants of the i-MiEV, including the two minicab MiEV versions sold in Japan, global sales totaled over 50,000 units since 2009.
History Mitsubishi i-MiEV, based on the Mitsubishi i kei car, was first exhibited at the 22nd International Battery, Hybrid and Fuel Cell Electric Vehicle Symposium & Exposition in Yokohama. Mitsubishi eschews the in-wheel motors (MIEV) in favour of a more conventional array of batteries, motor and inverter to replace the "rear midship" engine and fuel tank of the conventional car. Mitsubishi Motors provided three power companies with vehicles in 2006 and 2007 in order to conduct joint research to evaluate how fast-charge infrastructure may be developed for EVs. Fleet testing by five power companies was conducted in 2007. The car had a range of for the 16 kW⋅h lithium-ion battery pack and for the 20 kW⋅h pack. Top speed was .
Plans were announced in 2008 to sell the i-MiEV in European markets as the Peugeot iOn and Citroën C-Zero. Mitsubishi began supplying the electric cars to PSA Peugeot Citroën (PSA) since 2010, and PSA has a contractual commitment to buy 100,000 i-MiEVs over a period that remained confidential.
Specifications
Powertrain The production version of the 2009 i-MiEV has a single permanent magnet synchronous motor mounted on the rear axle with a rated peak power output of (between 2500 and 8000 RPM) and torque output of (between 0 and 2000 RPM). The continuous power rating is . The North American model had a rated stall torque output of (between 0 and 300 RPM).
The motor is water cooled, there is a conventional automobile radiator in the front of the car with an electric fan. The coolant (with antifreeze) level is monitored via a tank under the rear load platform on the left hand side of the vehicle.
The vehicle uses a single-speed reduction gear transmission driving the rear wheels and has a 16 kWh lithium-ion battery pack. The car's top speed is .
Under its five-cycle testing, the US EPA rated the American 2012 model year Mitsubishi i with a combined fuel economy equivalent of 112 MPGe (2.1 L/100 km), with an equivalent in city driving and on highways. This rating allowed the 2012 Mitsubishi i to get a higher MPG-e rating than the 2011 Nissan Leaf, which was rated at 99 MPGe (2.4 L/100 km) combined, but the Leaf rated a better range due to the Mitsubishi i's smaller battery pack. Consumption was rated at under the NEDC, with a maximum range of under that cycle.
Battery
The lithium-ion battery pack consists of 88 cells placed under the base floor. The pack has 12 cell modules connected in series at a nominal voltage of 330 V. There are two 4-cell modules placed vertically at the center of the pack and ten 8-cell modules placed horizontally. The cells are designated LEV50, developed by Mitsubishi and GS Yuasa for both high specific energy and high rate discharge and manufactured by Lithium Energy Japan, a joint venture of GS Yuasa Corporation, Mitsubishi Corporation and Mitsubishi Motors Corporation.
The entire pack has a specific energy of 80 Wh/kg. Each cell has a nominal voltage of 3.7 V and capacity of 50 A-hr (185 W-hr), measuring (H×W×L) and weighing . A four-cell module connected in series with 14.8 V and the same 50 A-hr (740 W-hr) capacity, designated LEV50-4, measures (H×W×L) and weighs . The battery has a forced air cooling system to prevent overheating during high charge and discharge rates and consequent damage; an optional heater is available for charging during cold weather. There is an integral fan in the battery pack. For rapid charging, the battery pack is additionally cooled with refrigerated air from the car's air conditioning system.
N-variant cells From the 2013 model year onwards, the cells used in the battery were switched from the LEV50 to the LEV50N. At this time, the Peugeot iOn and Citroën C-Zero batteries were reduced to 80 cells, while the i-MiEV continued with 88 cells; because the individual LEV50N cells each had the same capacity as the LEV50 cells, the overall battery pack was reduced to 14.5 kW-hr for the iOn and C-Zero, but improvements in the regenerative braking efficiency meant the range was unchanged. The "N" variant featured improved life under high discharge current and ambient temperatures due to an electrolyte additive which reduced internal resistance.
SCiB-variant cells In June 2011 Mitsubishi announced it would adopt Toshiba's Super Charge Ion Battery (SCiB) technology for its two new models of electric vehicles, the i-MiEV and Minicab MiEV. The SCiB technology uses lithium titanate oxide chemistry; Toshiba stated that its SCiB batteries can withstand 2.5 times more charge/discharge cycles than a typical lithium-ion battery. In addition, recharging via CHAdeMO takes much less time than charging at the AC Level 2 rate used by most electric vehicle supply equipment (EVSE), allowing the SCiB battery to reach 80% capacity in 15 minutes, 50% in 10 minutes and 25% in 5 minutes. Total capacity with the SCiB technology was 10.5 kW-hr.
The SCiB battery offers a higher effective capacity than a typical lithium-ion battery, which combined with more efficient regenerative charging during braking or coasting downhill, allows the SCiB battery to deliver 1.7 times the driving range per charge of a typical lithium-ion battery of the same size. Alternatively, the carmaker could install a smaller battery with less weight and keep the same range to contribute to lower the vehicle price as compared to lithium-ion batteries. Recharging is estimated to take 14 hours from a 110-volt power supply, 7 hours from a 220-volt power supply and as little as 30 minutes from a quick charging station.
The SCiB battery was only available in the Japanese model. Other markets retained the LEV50 or LEV50N lithium ion cells.
Charging (types and modes)
It includes two types of charging inlet connectors:
CHAdeMO: On the left hand side of the car, towards the rear, is the “rapid” DC charging point. It is beneath a cover (released from inside the car), there is a dust cover beneath to keep out insects etc. There are two large pins (for the charging current) and eight small ones for control circuitry. The cable used for this purpose is captive to the roadside charging point. When the car is on fast (DC) charge, the air conditioning system is automatically started and refrigerated air is blown through the battery pack for cooling purposes. There is a diverter flap in the ventilation system for this. From depletion, the battery may be charged to 80% full in 30 minutes using this socket. Yazaki: On the right hand side of the car is the “fast” and “slow” AC charging point, accessed in a similar way to the DC charge point. This is a five pin IEC62196 Type 1 point. Three large pins are the line, neutral and earth/ground. The two small pins are a control circuit. This circuit enables the charge current to be cut off when charging is complete, cuts off power if the plug is removed from the vehicle (the plug and socket are both unshuttered), prevents both rapid and fast charging being done simultaneously and also prevents the vehicle from being driven while the plug is inserted. For “fast charging”, the control box (mounted at the roadside) is limited to 16 amps enabling a charge time (from depletion) of five hours. For “slow charging”, a non-captive lead/cord is provided with the car. It is intended for use in the home or other domestic places. This has a local plug at one end and a Yazaki connector at the other. There is an in-line control box in the middle of this lead/cord that functions similarly to the fast charger but limits current to 10 Amps, enabling an eight-hour charge time (from complete depletion on 230 volts).
Emergency power supply and V2G
In the aftermath of the 2011 Tōhoku earthquake and tsunami, Mitsubishi introduced one year ahead of schedule a device called MiEV Power Box that enables the i-MiEV to supply power to home electric appliances in the event of a power outage or natural disasters. The device provides 100-volt outlets, converting the i-MiEV's direct current (DC) battery power into 100 volts alternating current (AC) to power up to 1,500 watts of small electrical equipment. Mitsubishi estimates that the i-MiEV total battery capacity is enough to provide power for between 5 and 6 hours, equivalent to one day of power consumed by an average Japanese home. The device was scheduled to be available by the end of April 2012, at a cost of () but as of November 2013 it is not clear if this is widely available.
On the other hand, Mitsubishi HEMS (Home Energy Management System), is the V2G system.
Regenerative braking control
The manufacturers have made every effort to make the very different technology of this car appear similar to conventional cars. The lever between the front seats appears to be an automatic transmission control but is not so, though it works in a similar fashion. It is in fact a switch which reverses the electric motor and also controls the strength of the regenerative braking through a driving mode selector. Correct use of the regeneration control can influence the range of the car.
As well as "park" "neutral" and "reverse" there are three driving mode positions that affect the strength of regeneration, intended for city driving (D), hilly terrain (B), and flat terrain (C) respectively; the North American model is labeled (E)co instead of (C). Used correctly, on most journeys, a large percentage of kinetic energy and potential energy can be returned to the battery. Lifting off the accelerator/"gas" pedal also induces regeneration as does light pressure on the foot brake. The only other mechanical losses are frictional. The main loss is aerodynamic drag which is proportional to the square of speed, hence high speeds are inefficient and reduce range.
Regeneration and power consumption can be monitored by the driver with an analogue instrument surrounding the digital speedometer on the dashboard/control panel which shows both instantaneous power consumed (needle moving to the right of its resting neutral position) and regeneration (needle moving to the left).
Electrical equipment