Nissan Leaf

Nissan Leaf, also formatted "LEAF" as a backronym for Leading, Environmentally friendly, Affordable, Family car) is a five-door hatchback electric car manufactured by Nissan and introduced in Japan and the U.S. in December 2010. The U.S. Environmental Protection Agency official range is 117 kilometres (73 mi), with an energy consumption of 765 kJ/km (34 kWh per 100 miles) and rated the Leaf's combined fuel economy at 99 miles per gallon gasoline equivalent. The Leaf has a range of 175 km (109 mi) on the New European Driving Cycle.

Deliveries to individual customers began in the United States and Japan in December 2010, in Ireland in February 2011 and in the U.K. in March 2011. Deliveries to corporate customers began in Portugal in December 2010 and sales to individuals are expected to begin in early 2011. Sales to individuals are scheduled to begin in the Netherlands in June 2011, followed by Switzerland, Spain, and France, with global market availability planned for 2012. According to Nissan initial availability is limited in quantities and to select markets and only for customers who made online reservations. The availability will be increased by the second quarter of 2011 with U.S. production planned for 2012.

The Leaf's retail price in Japan starts at ¥3.76 million and US$32,780 in the United States. The price in the United Kingdom is GB£30,990 and around €35,000 in the other six European countries where it will be launched first. These prices include the price of the battery package. Most countries have applicable tax incentives or subsidies for eligible buyers that reduce the effective cost of purchase below the retail prices listed by Nissan.

As an all-electric car, the Nissan Leaf produces no tailpipe pollution or greenhouse gas emissions at the point of operation, and reduces dependence on petroleum. Among other awards and recognition, the Nissan Leaf won the 2010 Green Car Vision Award award, the 2011 European Car of the Year award, the 2011 World Car of the Year, and ranks as the most efficient EPA certified vehicle for all fuels ever.

Specifications

Design

The Leaf's frontal style is characterized by a sharp V-shape design with large, up slanting light-emitting diode (LED) headlights that create a distinctive blue internal reflective design. The headlights also split and redirect airflow away from the door mirrors, which reduces wind noise and drag. The headlights consume 50% less electricity than halogen lamps. Nissan sought to make the Leaf appealing to mainstream drivers by giving it a familiar sedan- and hatchback-like design. The bottom of the car has aerodynamic paneling to reduce drag and improve aerodynamics as much as possible.

Powertrain

Nissan says that the car has a top speed of over 150 km/h (93 mph). Its motor is rated at 80 kilowatts (110 hp) and 280 newton metres (210 lb·ft). Unofficially, 0 to 60 mph (0 to 97 km/h) performance has been tested at 9.9 seconds.

The Leaf uses a front-mounted electric motor driving the wheels, powered by a 86 megajoules (24 kW·h) lithium ion battery pack rated to deliver up to 90 kilowatts (120 hp) power. The pack contains air-cooled, stacked laminar battery cells with lithium manganate cathodes. The battery and control module together weigh 300 kilograms (660 lb) and the specific energy of the cells is 140 W·h/kg. Each battery pack costs Nissan an estimated US$18,000 (as of May 2010). Under its five-cycle testing, the United States Environmental Protection Agency found the Leaf's energy consumption to be 765 kJ/km (34 kWh/100 miles) and rated the Leaf combined fuel economy equivalent at 99 MPGe (2.4 L/100 km), with an equivalent 106 mpg-US (2.22 L/100 km; 127 mpg-imp) in city driving and 92 mpg-US (2.6 L/100 km; 110 mpg-imp) on highways.

Battery

The 24 kWh battery pack consists of 48 modules and each module contains four cells, a total of 192 cells, and is assembled by Automotive Energy Supply Corporation (AESC) – a joint venture between Nissan, NEC and NEC Energy Devices, at Zama, Japan. Since the battery is the heaviest part of any EV, Nissan housed the battery pack below the seats and rear foot space to keep the center of gravity as low as possible and also results in increased structural rigidity as compared to a conventional five-door hatchback.

The battery pack is expected to retain 70% to 80% of its capacity after 10 years but its actual lifespan depends on how often fast charging (440-volt) is used and also on environmental factors. Nissan stated the battery has a "lifespan of 5–10 years under normal use". The Leaf's battery is guaranteed by Nissan for eight years or 100,000 miles (160,000 km) (see Warranty sub-section below under United States for limitations).

In addition to the main battery, the Leaf also has an auxiliary 12-volt lead-acid battery that provides power to the car computer systems and accessories such as the audio system, supplemental restraint systems, headlights and windshield wipers. The small solar panel on the Leaf rear spoiler (in the United States, only comes with SL trim) helps to charge this accessory battery.

Nissan recommends owners the following preventive actions to help maximize the lithium-ion battery’s useful life and its ability to hold a charge:

Avoid exposing a vehicle to ambient temperatures above 120 °F (49 °C) for over 24 hours.

Avoid storing a vehicle in temperatures below −13 °F (−25 °C) for over 7 days.

Avoid exceeding 70 to 80% state of charge when using frequent (more than once per week) fast or quick charging.

Allow the battery charge to be below at least 80% before charging.

Avoid leaving the vehicle for over 14 days where the Li-ion battery available charge gauge reaches a zero or near zero (state of charge).

Range

According to Nissan, the Leaf's expected all-electric range is 160 kilometres (100 mi) on the EPA city driving cycle and remains the same as the EV-11 prototype. However, the United States Environmental Protection Agency official range is 117 kilometres (73 mi) based on the five-cycle tests using varying driving conditions and climate controls. The Federal Trade Commission, which is supposed to label all alternative-fuel vehicles, disagrees with the EPA rating, and considers that the correct range is between 96 to 110 miles (154 to 180 km). Although the FTC does not conduct its own tests as EPA does, it relies on a standard set by SAE International and the results reported by automakers. The Leaf has a range of 175 km (109 mi) on the New European Driving Cycle.

Based on third-party test drives carried out in the US, reviewers have found that the range available from a single charge can vary up to 40% in real-world situations; reports vary from about 100 kilometres (62 mi) to almost 222 kilometres (138 mi) depending on driving style, load, traffic conditions, weather (i.e. wind, atmospheric density), and accessory use. Nissan tested the Leaf under several scenarios to estimate real-world range figures, and obtained a worst case scenario of 76 kilometres (47 mi) and a best case scenario of 222 kilometres (138 mi). The following table summarizes the results under each scenario tested using EPA's L4 test cycle and presents EPA rating as a reference:

Summary of the Nissan's results using EPA L4 test cycle

operating the Leaf under different real-world scenarios

Driving

condition Speed Temperature Total Drive

Duration Range Air

conditioner

mph km/h °F °C mi km

Cruising (ideal condition) 38 61 68 20 3 hr 38 min 138 222 Off

City traffic 24 39 77 25 4 hr 23 min 105 169 Off

Highway 55 89 95 35 1 hr 16 min 70 110 In use

Winter, stop-and-go traffic 15 24 14 −10 4 hr 08 min 62 100 Heater on

Heavy stop-and-go traffic 6 10 86 30 7 hr 50 min 47 76 In use

EPA five-cycle tests n.a. 73 117 Varying

Consumer Reports tested a Leaf loaner under cold-weather driven as a daily commuter. The average range obtained was 105 kilometres (65 mi) per charge with temperatures varying from 20 to 30 °F (-7 to -1 °C). The magazine also reported one trip under a temperature of 10 °F (−12 °C) that began with the range panel indicator showing 32 kilometres (20 mi) remaining. After 13 kilometres (8 mi) the Leaf drastically lost power and dropped its speed and continued to run slower until the last stretch was completed almost at walking speed. Consumer Reports concluded that the Leaf works as designed under cold temperatures but a more accurate range indicator is desirable.

In June 2011 Nissan reported, based on data collected through the Leaf's advanced telematics system, that most Leaf owners in Japan and the U.S. drive fewer than 60 miles (97 km) per day. Nissan also found that on average owners charge their electric cars for two hours a night, and occasionally some owners drive two days on one charge.

Recharging

The Leaf has two charging receptacles: a standard SAE J1772-2009 connector for level 1 and 2 recharging (120/220 volts AC) and a JARI Level 3 DC connector designed by TEPCO for high-voltage, DC fast charging (480 volts DC 125 amps) that uses the CHAdeMO protocol.

Using the on-board 3.3-kilowatt (4.4 hp) charger the Leaf can be fully recharged from empty in 8 hours from a 220/240-volt 30 amp supply (5.2 kilowatts (7.0 hp) allowable draw) that can provide the on-board charger its full 3.3 kilowatts (4.4 hp) of usable power.

In North America and Japan using a standard household outlet (120-volt, 15 amp breaker, 12 amp maximum allowable draw, 1.4 kilowatts (1.9 hp)) and the 7.5-meter (25 ft) cable included by Nissan, the Leaf will regain approximately 5 miles of range per hour. This type of charging is intended for convenience use when making stops or for emergency charging if you are within a short range of the charging destination.

U.S. electrical regulations require a 240-volt charging station to be permanently wired to an AC outlet unless proper interlock mechanisms are available to ensure the charging current can be safely turned on and off.[68] Nissan selected AeroVironment to supply its charging dock and installation services in North America.

Using DC fast charging, the battery pack can be charged to 80% capacity in about 30 minutes. Nissan developed its own 500-volt DC fast charger that went on sale in Japan for ¥1,470,000 (around US$16,800) in May 2010 and plans to install 200 at dealers in Japan. Nissan warns that if fast charging is the primary way of recharging, then the normal and gradual battery capacity loss is about 10% more than regular 220-volt charging over a 10-year period. Other companies make compatible charging stations, and companies and local government have various initiatives to create networks of public charging stations 

Nissan plans to double the power of the on-board charger to 6.6-kilowatt (8.9 hp) by sometime in 2012 (2012 or 2013 model year). They are also studying the possibility of offering upgrades for the 2011 year model.

History of development

Nissan introduced its first battery electric vehicle, the Nissan Altra at the Los Angeles International Auto Show on 29 December 1997. The Altra EV was produced between 1998 and 2002, only about 200 vehicles were ever produced, and it was mainly used as a fleet vehicle for companies such as electric utilities.

Unveiled in 2009, the EV-11 prototype electric car was based on the Nissan Tiida (Versa in North America), but with the conventional gasoline engine replaced with an all-electric drivetrain, and included an 80 kW (110 hp)/280 N·m (210 lb·ft) electric motor, 24 kW·h lithium-ion battery pack rated to have a range of 175 kilometres (109 mi) on the United States Environmental Protection Agency's LA-4 or "city" driving cycle, navigation system, and remote control and monitoring via a cellphone connection through Nissan's secure data center to the car. The technology in the EV-11 was previously developed and tested in the EV-01 and EV-02 test cars, built with an all-electric powertrain that used the Nissan Cube (Z11) as a development mule. The EV-11 prototype was on display July 26, 2009. A week later, on August 2, 2009, Nissan unveiled its production version at its Yokohama headquarters and committed to begin retail sales in both the North American market and Japan at end of 2010.