Typically if a CEL turns on and off it means the problem is no longer present however pulling the battery leads means you cleared all memory in your ECU. Batteries do not smoke instead they create hydrogen gas (very flammable) from what it sounds like either you battery has an internal short sapping all the voltage produced by your alternator or inversely your alternator is producing too much voltage causing your battery to boil over. Is it a completely sealed battery? You could try to pull the caps on each cell and check the electrolyte and recharge or better yet start by replacing the battery and see if the problem persists. Also if you have a multimeter check what voltage your alternator is putting out by putting the leads to the terminals on the battery while the car is running. Too much or too little voltage will cause some very funky issues youll be looking at about 13v on the low end and about 14.3-14.7 on the high end of the spectrum. If youre running at 15+ or below 13 volts i would suspect theres an issue with the voltage regulator. Alternators almost never lose their ability to create a charge but instead an issue occurs with the voltage regulator unsure if your vehicle has an internal regulator or an ECU controlled regulator. Hope that helps and you figure out your issue bud!