At IDTechEx we are convinced that lithium-ion batteries will dominate the automotive scene over the coming ten years and possibly the coming fifteen years. During that time we shall see peak lead acid battery the biggest nail in its coffin being when electric vehicles more widely abandon them and even those conventional vehicles modified to stay legal under impending carbon dioxide laws abandon them, relying totally on lithium-ion units.
However, that is not to say that there are no other contenders. We have closely assessed the research and see lithium-sulfur as in the lead but with considerable challenges to overcome before it hits prime time such as life and volumetric energy density – being too big though lighter. See the IDTechEx reports, “Advanced and Post Lithium-ion Batteries 2016-2026: Technologies, Markets, Forecasts” and “Lithium-ion Batteries 2016-2026”. Also visit IDTechEx Show! in Santa Clara California 16-17 November 2016 with its extensive coverage of solid state batteries and others plus their future applications. 
Wild card
One wild card is the flow battery. Most people rightly see these as very large units suitable for grid applications such as peak shaving but one or two organisations are thinking the unthinkable about putting them in cars because they are headed for $100 per kWh and size and weight might just fit the bill in due course. Toyota’s advanced research people told us recently that they would not dismiss the possibility.
Nanoflowcell has been exhibiting sports cars it says will use their flow batteries in pure electric form at 48V and achieve 1000 miles pure electric range. Even that voltage is counter to received understanding on design of car powertrains. Pure electric cars are generally headed up towards 800V for light weight and performance. Yes there is a huge move to keeping conventional cars legal under impending pollution laws by making them 48V at least in part but not pure electric vehicles where 48V is typically only seen in very weak duty cycles such as golf cars and postal delivery vehicles. See the IDTechEx report, “Mild Hybrid 48V Vehicles 2016-2031”.
Nanoflowcell pure electric car with 1000 miles range said to be launching in 2016