^ While that may be true, I think it is more the exception than the norm.
All my replacement batteries for laptops (an OLD compaq, 2 toshibias) have been "OEM" supplied batteries. Acer, dell, HP ect - don't believe any of them manuf batteries they just contract out to an OEM that then slaps an appropriate label on the Battery. They may specify in the contract some specifications as to quality, but generally go with loest bider.