Is it true that battery energy density improves 5-8% per year? Does this represent an average or is it a consistent trend each year?
Leigh Christie, Electric Vehicle Engineer
Updated Sep 3, 2013
Originally Answered: Battery Technology: Is it true that battery energy density improves 5-8% per year?
As we all know, 5-8% growth is exponential growth. While this is much “slower” than Moores law, it’s still the kind of growth that predicts fantastic things for our future given enough time. For example, if we wait 48 years, 8% compounded annually would give a battery that has a gravimetric energy density that exceeds that of gasoline!
But when we actually look at the curves for battery chemistries they are almost always linear. So why, then, do they say that “battery energy densities improve at 8% per year”? The answer lies in this graph: