Lets take this as objectively as possible, using Batman's appearance in his movies and the Avengers in their movies.
Iron Man: Has tech that is at least as good as Batman's, and at most alone makes the match up unwinnable. Tony's made so many suit upgrades he probably would have had a better shot at beating Superman than Batman himself. While that last bit might be a bit much, Tony's definitely got better toys at his disposal than Bruce.
The Hulk: There is literally -nothing- Batman can do to the Hulk in a fight. The only reason this isn't a 0-100 is because there's a chance one of Batman's toys might be able to knock Bruce out before he goes Hulk, but it's still basically such because in this continuity, Bruce has eaten fucking bullets and had the Hulk spit them back out. So have fun with that.
Black Widow: SHIELD's best, but still defeat-able in stealth and in melee combat, where both fighters excel.
War Machine: Iron Man with slightly less spacey tech, more shoot-y tech. A little more in Batman's favor, but still a loss, even if slightly less likely.
Thor: Hey, it's -literally- Superman. Except the bulk of his super strength (even though his hand to hand is pretty good) is inside an unstoppable unblock-able hammer. And no Kryptonite.
Hawkeye: Better at the long range than Black Widow, but probably not as good at the close range. Another one where Batman actually has fair odds. Probably easier to win than Black Widow, actually.
Captain America: Now, Cap could take Bats in a fist fight pretty solidly. Super Soldier drugs and all. But he doesn't have the same ways to get around stealth that the other characters who would need to worry about it do. So this is one Bats could win if he can Sneak Attack, rather than make an outright fight.
The Winter Soldier: A slightly stronger Cap with an arguably worse weapon, but with better use of Stealth and Secrecy. I wouldn't call this harder than Cap overall, though.
The Falcon: The wings are awesome for mobility and defense, but otherwise Sam's just a well trained human. The hardest of the 50-50 match ups, but still doable. Probably the easiest of them if Bats can get him into melee grounded territory, and it wouldn't be as hard as it would be against Iron Man or War Machine.
Scarlet Witch: That barely-trained human-female physique ain't doing her no favors in this match up. If Bats can get the drop on her, she's done. Granted, the fact that she can block bullets, psychic grab him, and drop him into the center of the earth's core if she wanted to means if he screws up his surprise round he's done.
Vision: Hey, it's -literally- Superman 2! Except no Kryptonite! And you can't even punch him! This one's outright unwinnable.
Ant Man: Yeah, have fun getting carried around by the bullet with the punching power of a Tank-Doing-A-Wheelie.
Black Panther: Were it not for the fact that his suit, which would protect him from about 90% of Batman's weapons and makes him even harder to fight than the Winter Soldier, is vulnerable to electricity, I'd put this one with the "Batman Loses". But given that Batman -does- carry weapons that would be useful against him, this one's possible, though not easy. Though Black Panther only got taken down because Black Widow took him entirely unaware, and not in a "I didn't know you were there" sense. Bats has one shot at that sort of tech before Panther knows to dodge it.
Spider Man: This one, on the other hand, had 30 minutes of screen-time and is already heavily stacked against Batman.
So, the Match-Ups.
Hard Counters
vs Vision: 0-100
vs The Hulk: 5-95
vs Thor: 10-90
vs Ant Man: 15-85
vs Spider Man: 20-80
vs Iron Man: 25-75
vs War Machine: 30-70
Possible with Stage Control or Strategy
vs Scarlet Witch: 35-65
vs Black Panther: 35-65
vs The Winter Soldier: 40-60
vs Captain America: 40-60
Neutral as is.
vs The Falcon: 45-55
vs Black Widow: 50-50
vs Hawkeye: 50-50
So, of the Avengers, he's got a hell of disadvantage against Vision, Hulk, Thor, Spider Man, or Antman; Iron Man and War Machine would be hard as hell; Scarlet Witch and Black Panther would be possible but still difficult and if he messes up his one advantage in each regard the fight becomes anywhere from harder to unwinnable; Winter Soldier and Captain America would be hard but doable; and Falcon, Black Widow, and Hawkeye are all relatively fair match ups.
I don't subscribe to the "Batman can beat up anyone if he has time to prepare for them" mentality, despite being a -MASSIVE- fan of the Justice League and Justice League Unlimited series. Consider in this scenario if he has time to look up any of these heroes, then either SHIELD, the Avengers People, or Stark Tech would have no less time to look up on Batman and pretty much even out any advantage gained. Nor am I counting any random bullcrap from the comics on either side. Just going off of the latest canon set of movie portrayals, giving Batman the Dark Knight series to give him a bit more ammo, since otherwise it'd be -just- BvS to draw from (and given that the entire movie was spoiled in the trailers and I've been warned/made aware the massive problems with Tone still haven't been addressed, I can't use BvS' info because I've no intention of wasting my money on it), and just using what was demonstrated in the Avengers Movies so far (with a nod at the slightly extended but still MCU canon for the existence of people to be able to check up on Batman and provide the Avengers info on him if he wanted to come knocking).