I bought a long life battery for my HP on Ebay a few years ago. I asked the seller specificaly if it was made in Japan. They assured me it was.
When I got the battery, the package said: Made in China. I tried it and it didn't work. It just wouldn't hold a charge. When I complained to the seller, they said "the cells" were made in Japan, but the battery was assembled in China. I was able to return it for a refund, but I lost shipping charges both ways.
I ended up buying an HP 8 hour battery at CompUSA for about $50 more than I paid for the Chinese one.
Bottom line: Don't buy batteries on Ebay. Of course, YMMV.

Matt