What makes Batman special isn't just that he's pushed his body to the limit, but also his mind. That being said, he acknowledges that he doesn't know everything, and thus respects those who match him in intellect in fields he doesn't fully know. One such person is Ray Palmer, aka The Atom.
Palmer is a master of microbiology, to such a degree in fact that he created a suit that would allow him to shrink himself to the size of a literal Atom. This comes in great handy when needing to slip into somewhere undetected, or just in battle to get around enemies as he fights them.
Ray has been seen with Batman in many shows, including Justice League Unlimited and Batman: Brave and the Bold. Both times he acknowledges Ray's gifted intelligence.