An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy.

There are two types of battery: Primary batteries (disposable) which are designed to be used once and then discarded; and Secondary batteries (rechargeable) which are designed to be recharged and used multiple times.  Miniature batteries are used to power hearing aids and wristwatches, - much larger batteries can provide  back up power for telephone exchanges or computer data centres.

Secondary batteries are not infinitely rechargeable, due to the dissipation of the active materials, loss of electrolyte and internal corrosion.

Battery life can be extended by storing the batteries at a low temperature ( as in a fridge), which slows the chemical reaction in the battery. To reach their maximum voltage, batteries must be returned to room temperature before using.

Recycling batteries in New Zealand

Your local garage may also accept batteries for recycling.

Mobile phone batteries

Recycle your old mobile phone with Vodafone  or Telecom. These phones contain nickel and cadmium, both of which can be extracted for recycling, although the only factory that currently does so is in France. Starship Hospital has recovery boxes in many district and city council offices.

Dry Cell and disc or button batteries

Dry cell and disc or button batteries contain heavy metals such as silver, nickel, cadmium, lead, mercury, lithium, manganese and zinc, all of which can accumulate and concentrate in water, wildlife and humans. If not recyclable, put in your rubbish bin.


Explosions are generally caused by the misuse or malfunction of a battery – like attempting to charge a non-rechargeable battery.

When a battery is rapidly recharged, like jump starting a car, an explosive gas mixture of hydrogen and oxygen may be produced faster than it can escape from within the walls of the battery, leading to pressure build-up and the possibility of the battery case bursting.

Many battery chemicals are corrosive, poisonous, or both. If leakage occurs, either spontaneously or by accident, the chemicals released may be dangerous.

Environmental benefits of recycling

Approximately 85% of a vehicle battery can be recycled. These batteries contain plastic, lead and sulphuric acid. Around 500,000 vehicle batteries are sold in New Zealand each year, with less than 400,000 returned for recycling.

Environmental effects

Batteries, when dumped in the environment, can cause significant damage when the contents leak. The widespread use of batteries has created many environmental concerns, like toxic metals pollution. Battery manufacturing consumes resources and often involves hazardous chemicals. Elements such as lead, mercury and cadmium are likely to be present.

Batteries may be harmful or fatal if swallowed, and young children are particularly at risk from button or disc batteries.