He's human, frail and fragile. He only appeared to have won in their battles in the comics because Superman has no intention of beating him to death. You can arm Batman with a Kryptonite arrow, a Kryptonite gun and even a Red Sun generator, but it won't matter to a person who could move at superluminal speeds and kill…

Stan Lee is right. Superman is all powerful while Batman relies on gadgets and weapons that may or may not have an effect on Superman, but if it does, would likely have a minimal effect and would not result to him dying.