There will be too many companies making too many batteries for electric vehicles by the middle of the decade, according to a study quoted by the Wall Street Journal.

"There's clearly going to be overcapacity around 2014 and 2015, if you just take the number of vehicles that will be produced and do the calculation of how many batteries will be needed,"  Oliver Hazimeh, partner and head of the global e-mobility practice at PricewaterhouseCoopers, told the WSJ.

The consultancy expects the overall global electric-vehicle industry to reach US$300bn by 2020, including a possible $50bn for battery manufacturers. 

Although today's installed capacity is still well short of what will be needed by 2020, the announced capacity investments will far exceed the projected demand from automakers as production kicks in.

This will lead to consolidation with some companies being bought and others "vanishing because they don't get enough business", said Hazimeh.

Udo Rugheimer, a spokesman for SB LiMotive, a joint venture between Germany's Robert Bosch and South Korea's Samsung, agrees. "We'll come down to a single-digit number between 2015 and 2020," he said. There are around 20 EV battery makers currently. SB LiMotive is due to start manufacturing electric vehicle batteries in 2013. 

Overcapacity is expected to become most acute toward the middle of this decade as factories financed by the recent investment wave come on stream. And given that the technology is still evolving, "people are becoming more cautious right now in terms of not flooding the market too early with first-generation products," Hazimeh said.

Renault recently decided to postpone the start up of a battery manufacturing facility near Paris to 2014, a decision possibly reflecting a more cautious approach among vehicle manufacturers, although the company has said it was delayed because Renault and Nissan have decided to restructure the project and go it alone without state sector partners.