Nikkei Electronics Asia -- October 2009
Features
Nissan to Produce Major Parts for Electric Vehicle In-House

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Oct 7, 2009 00:00 Naoshige Shimizu

Nissan Motor Co Ltd of Japan held an advanced technology press conference in late July 2009, offering a glimpse at the technology that will be used in the electric vehicle (EV) slated for release in Japan, the US and Europe from the second half of 2010 (Fig 1). On August 2, 2009, the company also announced the vehicle will be called "Leaf," and released exterior shots.

Carlos Ghosn, president and CEO of Nissan Motor, said he expects the Leaf to be priced at "... about the same level as a gasoline-fueled vehicle of the same size" - that is, about Yen2 million.

Designed for US Market

In May 2009, Nissan Motor announced its EV plan and revealed its ambitions for "50,000 units annual production from the fall of 2010" and "200,000 units annually worldwide in 2012." 

In keeping with its enthusiasm for the project, Nissan Motor is also pushing a range of technologies for the Leaf.

Motors, inverters and other key parts will be manufactured in-house, with motors at the firm's Yokohama Factory and inverters at the Zama Factory. These will be mounted on dedicated chassis at the Oihama Factory. As previously announced, the Li-ion rechargeable batteries will be manufactured at the Zama Factory by Automotive Energy Supply Corp (AESC), a joint venture between Nissan Motor, NEC Corp and NEC TOKIN Corp, all of Japan.

The vehicle's size seems to be designed for the US market: a relatively large EV holding four or five people as a small- or mid-size car. Max motor output is 80kW, and torque 280Nm, both fairly high. According to a source at Nissan Motor, it will "Cruise comfortably on American highways." Max speed will be at least 140km/h. This should put the gross vehicle weight at 1.6t to 1.7t, which is 20% to 30% heavier than the compact-based i-MiEV electric vehicle announced by Mitsubishi Motors Corp of Japan in July 2009.

To achieve a reasonable cruising range in spite of the heavier build, the capacity of the Li-ion rechargeable batteries is also boosted to 24kWh, or 8kW larger than those of the i-MiEV. The number of storage cells has been upped to 192 to gain the larger capacity, with modules of two series-linked cells connected in parallel to prevent the voltage from rising.

Modules weigh 3.5kg, and with 48 modules that comes to 168kg, plus with cases, cabling, etc, the weight is likely to end up at about the same 230kg as the i-MiEV.

Average voltage for the entire battery system has been announced as 345V, which means each cell is about 3.6V. The mass energy density is estimated at about 140Wh/kg.