Details on Nissan Leaf battery pack, including how recharging speed affects battery life

Interesting....
Nissan broke ground on a new battery plant in Smyrna, Tennessee yesterday (figuratively, anyway, the actual bulldozing doesn't start for a few weeks). For now, we will call this the U.S. Leaf battery plant, but it's really part of Nissan's strategy to electrify more and more of its vehicles. As we mentioned yesterday, once it is up and running at the end of 2012, the plant will have the capacity to make 200,000 battery packs a year. The nearby vehicle assembly facility where the U.S.-built Leafs will come to life will have a maximum capacity to make 150,000 Leafs a year alongside other Nissan vehicles like the Altima and Pathfinder. The extra capacity, if used, could be sold to other automakers or go into non-Leaf Nissan products.

In Smyrna yesterday, Nissan's director of product planning, Mark Perry, gave AutoblogGreen some more information on the Leaf battery pack. As we know, Nissan says the 24 kWh pack gives the Leaf a 100-mile range on the gentle LA4 cycle (meaning it probably isn't a totally reliable guide to estimate real-world driving). Still, this means the test packs have been charged and discharged a lot, because Perry said Nissan has done "hundreds of thousands" of miles of reliability testing on the battery packs, including dunking them in a pool and freezing them. Not that we'd expect him to say anything different, but Perry is confident that the battery pack is totally safe.

What's in the pack? 48 modules, each with four cells (so, 192 cells total) arranged in a big square. The part that sits under the real seat is a little taller than the rest, as the modules are stacked vertically while the other modules lay horizontal under the front seats and floor. The entire pack weighs around 600 pounds and contains around 9 pounds of lithium. How will people use the Leaf? Find out Nissan's expectations after the jump.

Once out in the real world, Nissan expects most Leaf charging to be done using Level 2 (240V) units, because that's what most people will get at home and what will be used in public chargers. Level 2 chargers can get the pack from zero to 100 percent in about eight hours. Level 3/direct quick charging could happen, but it's not widely available yet. Meanwhile, Level 1, aka recharging from a standard 110V outlet, will be "more for emergencies," Perry said. It'll also take ages (think 20+ hours).

How you recharge the pack will affect its life. Nissan has said it expects to Leaf drivers to have around 70 to 80 percent capacity left in the pack after ten years. What will get drivers to the upper or lower end of that range? The amount of fast charging one does. With regular Level 2 charging, drivers should expect 80 percent live left in the battery. With a lot of Level 3 charging – two or three times a day – the pack will only be at the 70 percent level. Level 3 charging is appealing because it can get the battery from zero to 80 percent full in under 30 minutes, but there is a very clear drawback if it becomes a habit. Perry said that most people will be happy with 240V home charging:

The people who drive EVs today, they talk about charging like this: "Charging to me is five seconds. I plug it in, I walk away and forget about it." To them, it's really pretty simple.

What might be coming down the road? Perry said there is no Moore's law in battery production, but did say Nissan is seeing about an eight percent improvement in things like cost reduction, range and efficiency, year over year. Whether this results in cheaper packs or lighter/smaller/better ones will depend on what the early adopters do with their Leafs and what they tell Nissan they want. What's your preference?

PRESS RELEASE
Type: Laminated lithium-ion battery
Total capacity (kWh): 24
Power output (kW): Over 90
Number of modules: 48
Battery pack contents:
-Positive electrodes
– Lithium manganate-Negative electrodes
– Carbon-Cells-Modules-Assembly parts
Charging times:
-Quick charger DC50kW (0 to 80%): apx. 30 min
-Home-use AC240V charging dock (0-100%): less than 8 hrs
Battery layout: Under seat & floor
Battery life: After 10 years, the battery is expected to have 70-80 percent of its original storage capacity.

Source;
http://green.autoblog.com/2010/05/27/details-on-nissan-leaf-battery-pack-including-how-recharging-sp/