A state-backed fund wants a venture owned by Nissan Motor Co Ltd and NEC Corp to merge with Sony Corp's lithium ion battery operations to prevent rivals in China and Taiwan from capturing key technologies, the Yomiuri newspaper said on Friday.

Sony, which is hurrying to offload noncore operations, makes lithium ion power packs for tablets, PCs and mobile phones. Sony values the unit - which has three factories in Japan and two overseas assembly plants - at 52 billion yen ($580 million).

The Yomiuri said Japan's Innovation Network Corp of Japan is encouraging the Nissan-NEC venture, Automotive Energy Supply Corporation, to buy a majority stake in Sony's battery unit.

The state-backed fund has also offered to invest in the merged firm but is also looking for other domestic buyers in case talks fall through, the paper said, citing sources familiar with the matter.

($1 = 90.0000 Japanese yen)