High costs of lithium-ion battery cells have been one of the main hindrances to large-scale electric-car adoption, as they typically lead to higher purchase prices for electric cars than comparable internal-combustion models.
But electric-car battery prices are falling fast, according to one recent study.
Global Trends in Renewable Energy, calls the price drop in batteries for electric cars "spectacular."
Citing improved chemistry, manufacturing processes and economies of scale, authors of the study (pdf) at the Frankfurt School of Finance & Management see a bright future ahead for electric cars.
According to the study, average electric-car battery costs declined every year between 2010 and 2015.
Between 2014 and 2015, average costs decreased by 35 percent.
In addition to cost reductions achieved through changes to cell chemistry and manufacturing processes, the study also notes cost decreases due to "aggressive pricing" by large battery manufacturers looking to defend their market share.
Tesla's opening of a massive "Gigafactory" in Nevada to provide greater economies of scale is also cited as a contributor.
The company began producing lithium-ion cells at the Gigafactory this month, using them for its Powerwall 2 and Powerpack 2 energy-storage battery packs.
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Tesla hopes to begin cell production for the Model 3 electric car in the second quarter of this year, and expects to be making 35 gigawatt hours of cells per year at the Gigafactory by 2018.
Global electric-car sales reached 462,000 units in 2015, up from 290,000 in 2014, according to the study.
While sales have steadily grown since modern electric cars first went on sale in large numbers about six years ago, predictions about future growth differ widely.
2017 Nissan Leaf
2017 Nissan Leaf
But Bloomberg New Energy Finance estimates that 7.4 million electric cars will be on the road by that time, with 2 million sold in 2020 alone.
Bloomberg also expects electric cars to make up 35 percent of light-duty vehicle sales by 2040.
It's unclear which prediction will prove closer to reality, but lower battery costs can only help the cause of electric-car adoption.