RegGuheert
Well-known member
So, how are BEVs doing in terms of specific capacity of batteries?RegGuheert said:Carlos Ghosn has been quoted as saying that is the rate of capacity improvement they are seeing, but I cannot find the reference.donald said:What's your source for this data?RegGuheert said:Capacity of Li-ion batteries has been improving at a historical rate of 8%/year.
Here is another report which shows 7%/year: Comments on the History of Li-ion BatteriesSee Figure 3 about 18650 cell capacity. 1991: 1 Ah, 2001: 2 Ah
2009: Panasonic Develops New Higher-Capacity 18650 Li-Ion Cells; Application of Silicon-based Alloy in Anode: 4 Ah
I guess that last data point is a bit over 8%/year from 2001.
2011 Nissan LEAF: 24 kWh battery weighing 650 lbs. (295 kg) = 81 Wh/kg
2017 Chevy Bolt: 60 kWh battery weighing 960 lbs. (435 kg) = 138 Wh/kg
That's a 70% improvement in specific capacity in 6 years. That is a battery capacity growth rate of 9.3%/year, which exceeds both Ghosn's prediction and the historical rate of Li-ion capacity improvement seen in cylindrical cells.
More importantly, the range of BEVs has improved by 200 miles/84 miles = 2.4 times over the same period, which is a 15.6%/year rate of range improvement.
It seems that the range of BEVs is increasing more rapidly than the range of the 737, though I doubt this rate of improvement will continue into the future. Only time will tell.