The one on the right is one of the original 'Sony/Taiyo Corp' 970 batteries. These date back many years and from memory were available up to 2008. I have a couple of them, still working amazingly, dating back to the Sony PD-150 days. Sony and Taiyo Yuden formed a division back in 1987 for the manufacture of DVD blank stock. Still the best DVD blanks. They also produced audio equipment as well as batteries under the Sony/Taiyo brand. The one on the left is a 'Sony Corp' battery and I believe that is the newer battery as that Sony/Taiyo association is well over. Taiyo Yuden and JVC formed a DVD association in 2008 called Victor Advanced Media after Sony/Taiyo broke up.
As an aside. When I want the best DVD blanks plus BD archive discs that's what I use now. The JVC/Taiyo blanks.