::This is wrong. The burning reaction of a lithium-ion battery does produce oxygen, but this oxygen is minimum. Just think about it. How much oxygen do you think there is in a battery that weighs 50 grammes, the typical weight of a cylindrical cell? Once the cell is ruptured, the internal layers and electrolyte are completely exposed to the ambient air, which provides the oxygen for combustion. 
 ::I can verify by laboratory experiments, and also by reports such as the Exponent report, that water is basically the best fire extinguisher for this kind of batteries, due to the additional cooling effect on the cell. There seems to be a confusion with lithium-metal batteries. Pure lithium is the most reactive metal, and therefore it reacts violently with most compounds. It is lithium metal the one that spontaneously combusts when in contact with oxygen or water, and therefore it is not recommended to extinguish lithium-metal fires with water or even CO2, with which it also reacts. The only recommended extinguisher is a class D, which consists of copper particles to smother the flames. But lithium-ion cells are a different story. They don't have metallic lithium, only lithium compounds, and the fire is closer to a class A fire, meaning burning of general combustible material like the electrolyte and the plastic separator.