UPDATE 1-Ford JV partner SK sees U.S. battery shortage persisting until 2025

(Adds financing plan in final paragraph)

SAN FRANCISCO, Oct 4 (Reuters) - Ford Motor Co's battery joint venture partner, Korea's SK Innovation, expects the U.S. vehicle industry to face a battery supply shortage until 2025 because of the long lead times to build production facilities, top SK executives told Reuters.

SK Innovation's battery unit, SK On, is also considering developing lithium iron phosphate batteries (LFP), which have an advantage in cost and thermal stability despite a lower driving range, Kim Jun, chief executive of SK Innovation and Jee Dong-seob, CEO of SK On, said.

Tight supplies of batteries - key to electric vehicles - pose a challenge to the Biden administration, which aims to boost EV production and reduce the country's reliance on imports for battery cells, components and materials.

"The current U.S. battery capacity is far short of meeting demand. Building a factory to meet demand requires a lead time of 30 months, and I see a battery shortage continuing at least until 2025," Kim said, referring to the time needed to supply battery cells domestically, including factory site selection, construction and product testing.

In contrast, China is expected to have a battery oversupply, and Europe's supply will be in line with demand, he said.

Ford and SK On plan to invest $4.45 billion each to build three new factories in the United States, with production slated to begin in 2025.

With the deal for the plants, which will be the biggest in the United States, SK said it has an industry-leading order backlog of 1,600 gigawatt hours, enough for 27 million vehicles.

SK Innovation spun off its battery business into its wholly-owned unit, SK On, as of Oct. 1.

Kim said Ford Motor CEO Jim Farley told him that Ford's electrification destiny is "in your hands."

He said there was only a slim chance that some automakers would succeed in efforts to build cells by themselves without partnering with cell makers who have experience of mass production.

"Cell manufacturing is not that simple. It has to go through a lot of trial and error," Kim said.

SK is considering developing LFP batteries for specific applications such as low-priced vehicles, the two executives said.

"There is an interest in LFP technology from automakers," SK On's Jee said.

Ford and Volkswagen are diversifying into LFP technology, which is the mainstay of Chinese battery makers, following Tesla's lead.

The lower-range, cheaper LFP battery is also gaining attention for its thermal stability, after a series of vehicle fires involving nickel-based batteries produced by LG and used in GM's Bolt cars.

SK, which does not have a record of fire accidents, plans to produce high-nickel, pouch-type batteries at its joint venture with Ford.

SK On is considering other joint ventures and financing options, but will not hurry to go public, Kim said. (Reporting by Hyunjoo Jin; editing by Richard Pullin)