Accumulators and batteries store a lot of energy - that is, after all, their purpose. If this energy is released in a short period of time, fire and even explosions might occur. The main problem for fire protection is posed by the various oxides used in lithium-ion batteries. The oxides can decompose at high temperatures, releasing oxygen, which then burns with other materials, generating even more heat. This self-reinforcing process is called "thermal runaway".