It is clear that in the past few decades, lithium-ion batteries have improved in terms of various metrics – energy density, specific energy, power density, etc. while costs have also reduced significantly. 

This publication by Micah Ziegler and Jessika Trancik from MIT explores the correlation of the decline in price with improved technology (Moore’s Law), cumulative production (Wright’s Law), annual production (Goddard’s Law) and R&D activity as measured via patent filings.