Storage advice: Do not expose lithium cells to sub-zero temperatures

11/6/18, 5:00 PM -

While charging, the cells must not be exposed to temperatures below freezing point. If they are charged after all, dendrites could increase. Three or four charges during frost can already initiate such processes. 

Find a shady place to mount the battery modules.

The battery may also be located in the attic, but only if there is certainty that the ambient temperature never rises above 25 degrees Celsius. Also, any safety system that only covers parts of the battery, falls dangerously short.

Uncontrollable short circuits

All short circuits that occur before the fuse are uncontrollable. This includes flashovers between cells. Constant monitoring of the cells as to their thermal and electrical operating data shows excessive temperatures of the electrolyte in a timely manner.

Otherwise, there is the danger of the dreaded thermal runaway effect. This is when the battery ignites due to overheating, similar to the meltdown in a nuclear reactor. This can be a gradual process. One can be right next to it and do nothing to prevent it. Because once this process has started, it cannot be stopped.

So the battery needs to shut off the affected cells – and itself – in time. In case of a house fire, the battery needs to be cooled sufficiently. Otherwise, the thermal runaway effect can start once the fire brigade has already left again. (HS)

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