Rechargeable Batteries

46 (2008)

Rechargeable batteries are electrochemical cells in which the electrochemical reaction that releases energy is readily reversible.  Some commonly used chemistries include nickel-cadmium (NiCd), nickel metal hydride (NiMH), lithium-ion (Li-ion) and lithium-polymer (LiPo).

Rechargeable batteries are used in many modern devices including mobile telephones, laptop computers, digital cameras, portable games consoles, scooters, electric wheelchairs & cycles, and scientific and other equipment.

One area for concern with the use of rechargeable batteries is the possibility for them to be overcharged.

Chargers for rechargeable batteries should utilise a continuous-current/constant-voltage (CC/CV) charging regime, and have an auto cut-off function.  Where a charger does not have an auto cut-off function, it must be manually switched off to prevent overcharging of the battery.  Please consult your manufacturer’s documentation to determine the type of battery, charging system and the maximum time it should remain on charging.

If a rechargeable battery is overcharged, it has a risk of overheating, smouldering, fire and explosion.  In the event of overcharging, the charger should be immediately isolated from its power supply.  A carbon dioxide extinguisher is the best extinguisher to use on a rechargeable battery pack that is smouldering or on-fire.  Water or wet agents should not be used as an extinguishing agent, as the battery may react with water or there is a risk of electrocution.

Inhalation of smoke generated in fires of this nature should be avoided, as it could be detrimental to health.

Material safety data sheets (MSDS) for rechargeable batteries are available through Chemwatch Gold (http://chemgold.anu.edu.au/) or by contacting the manufacturer.