The Nissan Leaf runs on a 24 kWh lithium ion battery, with 48 modules of 4 cells each. The batteries are built by a joint venture between Nissan and NEC.
The batteries weigh about 600 pounds, but are mounted in the low center of the car, under the front seats and rear footwell. This mounting location results in both a lower center of gravity as well as increased frame rigidity.
How Long Will the Battery Last?
The Leaf battery is guaranteed for 100,000 miles or eight years, whichever comes first. Nissan estimates they'll retain 70% - 80% of charging capacity for ten years, depending on the type of charging system used to recharge the battery.
For instance, frequent Level 3 charging (the 440v used for rapid charging) with an industrial source of power will reduce the capacity over time. So, if you regularly charge your Leaf from that type of source, as opposed to the 220v charger you'd install at your home, you might reduce the charge capacity to 70% or less in ten years.
To increase battery life and extend capacity, Nissan recommends the following:
Try not to use the vehicle when the temperature is above 120 degrees fahrenheit for over 24 hours.
Avoid using the car when the temperature is below -13 degrees fahrenheit for over 7 days.
If you use fast charging (Level 3), try to avoid charging to more than 70% - 80%.
Try to drain the battery to below 80% for recharging.
Don't leave the car for more than 14 days where the battery will reach a zero or near zero state of charge.
Driving the Leaf in "Eco" mode will increase the use of regenerative braking, which means using the electric motor as a generator to charge the battery at the same time it increases load aids in deceleration.
The Nissan Leaf also includes an auxiliary lead-acid battery, which powers the car's computer and accessories such as the stereo, restraint systems, headlights and wipers. The more expensive SL model includes a solar panel integrated into the rear spoiler which charges the auxiliary battery.
Nissan expects these batteries to easily serve for 10 years. After that period, they can be used for storage applications such as solar power installations.
Nissan also expects an 8 to 10 percent increase in capacity every year, which can be used to either increase or reduce cost.
And, as a bonus for U.S. jobs, ground was recently broken on a Nissan plant in Smyrna, Tennessee which will manufacture the lithium ion batteries.
The plant is expected to build 200,000 batteries a year, which is 50,000 more than the nearby Nissan Leaf plant will produce. So, it looks as if Nissan expects good things for the EV market, and expects to sell the surplus batteries for other cars or applications.
It remains to be seen if the range estimates and charge capacity decline estimates from Nissan are accurate. Certainly, the temperature extreme warnings suggest that various environmental factors can effect battery charge and life.
The true test of the Nissan Leaf's battery will be real-world use by actual owners. Although all the evidence so far suggests the Leaf is a well manufactured and good driving vehicle, more mundane issues such as range, battery life, charging availability and general practicality as a consumer level vehicle will have to wait - probably for several years.