well i can tell you, those batterys if they short out will cause explosions and the cells will pop and gas that comes out of them can kill you almost instantly if inhaled.
i would not try to fix one, its very dangerous to go poking around a lithium battery.
either way, apple has individual cell control on the batteries, i believe if a cell dies thats it anyway, you cannot make the battery think its working again even if it(the cell) was replaced.