Hi
Are there many Electric cars in Korea? - do you guys have "scrap yards"? - vehicle dismantlers?
You will probably need to do a LOT of phoning around
The Americans have
http://www.car-part.com/
I'm in NZ - but I found a local "Hot Rod Import" company that shipped me a Volt battery from the USA (California) - using car-part.com
Most import companies seem to be scared of batteries - but the hot rodders weren't!
I hope some Koreans will join the discussion and tell you what they know