Batman would never defeat Superman in direct combat, however that's what Batman is all about; he would probably do something extremely ridiculous like leading Superman to a room made of lead, so that all outside radiation of the sun would be blocked out, and he would lose his super-powers. But in a direct combat? No. Never.

Magic and kryptonite, those are the only ways Batman could kill him in direct conflict, and since Batman isn't to much of a magician, kryptonite is pretty much his only option. Considering how many people Superman has beaten while they were using kryptonite it still is very unlikely Bats could win a straight up fight. Also, it takes hours for Superman's powers to drain when not exposed to sunlight

Everyone forgot that Superman could just go prime and just erase Bruce Wayne form existence.
Also one of Supermans forgotten powers is complete hypnosis. So he could tell batman to put a bullet in his head.

Superman gave him kryptonite. And Batman has a plan to stop every hero there is, just in case they go crazy or something.

Batarang coated in kryptonite dust.

But he did remember to make sure to get the hottest DBZ chick (And probably the strongest female Z Fighter) in the series, Android 18

thats true. maybe he set that one up to happen before he became krillin. and oh my god now jesus has a littler sister and neither of them realize holy fuck!