TOKYO, Sept 7 (Reuters) - Japan's Nissan Motor Co said on Wednesday it had agreed to acquire all the common shares in Vehicle Energy Japan Inc held by the lithium-ion battery maker's biggest shareholder.

Nissan added that after the acquisition of the shares held by the Innovation Network Corporation of Japan (INCJ), a state-backed fund, Vehicle Energy Japan will become its consolidated subsidiary, in which it will hold shares alongside existing shareholders Maxell Ltd and Hitachi Astemo Ltd.

Nissan did not provide any financial details of the deal.

Vehicle Energy Japan develops, manufactures and sells lithium-ion batteries for hybrid vehicles.

"The investment will allow Nissan to secure a stable battery supplier and contribute to the development of next-generation batteries with a competitive edge in terms of both performance and cost," Nissan said in a statement.

Stable supply of battery materials is among the many challenges being faced by automakers worldwide as stricter environmental regulations accelerate production and sales of cleaner, electrified cars.

Nissan's rival Honda Motor Co recently said that it had formed a partnership with trading company Hanwa Co to secure stable supply of essential metals used in batteries for electrified vehicles. (Reporting by Satoshi Sugiyama; Editing by Muralikumar Anantharaman and Himani Sarkar)