If Batman ever punched Wolverine in the face, then not only would Batman have the padding of gloves, and the protection of the metal that lines them, but his tender gentle hands would also be padded by the inch or so of flesh between wolverine's face and his skull.
Futhermore, since Batman typically hits pretty hard, Wolverine's head would be pushed, to some degree, backwards, resulting in further less pressure on Batman's hand from the blow. Now if Wolverine were an adamantium wall, then the glove padding wouldn't be worth much, but as is, Wolverine is a movable person, and thus, hitting him is a lot less painful than hitting a brick wall simply because he moves when you hit him. Wolverine is not invulnerable... just unkillable.
Aside from the fact that I have not mentioned Batman gassing Wolverine or any such madness, Wolverine fights Elektra, Captain America and other master martial artists pretty evenly. Batman, being on par with these skill wise would also fight Wolverine to a standstill, his claws being no more an advantage than Batman's boomerangs, both of which are fully capable of cutting up lots and lots of flesh.
While the chances of Batman and Wolverine meeting up in a free for all brawl between the X-Men and JLA are SUPER Slim, if they WERE to meet up, the fight would likely continue until one of their teammates came to help decide the battle... unless of course they were the last two standing, in which case, Wolverine would win... after four days of straight fighting of course...