Nissan’s Leaf is planning to bring pure electric driving to consumers sometime in late 2010 or early 2011. However, work is almost complete on development of more advanced batteries, ones that can double the amount of energy storage capacity of current batteries. More work is still ahead to bring them to market – manufacturing processes need to be worked out – but the goal is to have them power vehicles in 2015.
The estimated battery capacity would be around 250Wh/kg. This is about double of the current batteries (100-140Wh/kg), and assuming a commensurate increase in Wh/L, the batteries would get lighter and smaller for the same energy storage capacity. If we were to drop this battery in a hypothetical generation two LEAF, we could increase range to 130 miles city, 100 miles highway, and still reduce batter weight (and probably volume) by 25-30%. This would cut a 100-150lbs off the weight of the car (roughly 3-4% of curb weight), and would in turn extend the range of the battery another 3-4%.
The batteries are estimated to get 1000 cycles, presumably at 100% depth of discharge (DoD), which would provide 1500 cycles at an 80% maximum DoD, likely for pure EV applications like the LEAF. This would be suitable to deliver at least 150,000 miles of driving on the battery pack before it degraded to 80%, likely far more due to the relationship between average DoD, cycle life and maximum storage capacity – that is, the lower the average DoD, the more full cycles the battery can withstand before equivalent degradation.
Finally, this advancement pushes ahead the development curve of Lithium Ion batteries. For years, the average increase in capacity was 5-8%, but as more companies throw their hat into the ring of battery research and development, we’re starting to see batteries advance faster. We’ll likely never see batteries advancing as fast as microchips, but it is satisfying to see the rate of innovation ramp up. The electric car future might be here a little bit sooner than expected.
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