Tuesday, 6 November 2012

The Life, Death, and Resurrection of a Battery

In 2010, Canadians purchased 22,843 tonnes of batteries. Less than a third of those were rechargeable, and many ended up in landfills. We all use rechargeable batteries in our cell phones and laptops, in our calculators and our cars, but many of us still buy single-use batteries for portable devices like flash lights,  remote controls, and toys. About 88% of the total mercury and 50% of the cadmium found in municipal waste comes from batteries.

Recycling your batteries can help reduce mining of materials for battery production, as can buying rechargeable batteries. Furthermore, buying rechargeable batteries can also save you a lot of money. A pair of rechargeable AA batteries costs about four times as much as a two single-use AA batteries, but you can use your rechargeable batteries hundreds of times!

What is a battery?
Simply put, a battery is a portable source of energy that produces electricity by chemical reaction. The amount of electricity a battery produces varies widely depending on the type and amount of materials used to construct the battery.

How does it work?

A battery is made up of one or more “cells” which comprise two different metals (electrodes) connected by wire on one end, and in contact with an electrolyte solution on the other. One electrode has an excess of electrons (a negative charge) and one has a deficit of electrons (a positive charge). The chemical reaction between the metals and the solution causes electrons to travel from the negative terminal to the positive terminal, producing electricity.
Common Batteries

A battery will either be wet-cell, where the electrolyte solution is liquid (as in a car battery), or dry-cell, where the electrolyte solution is a paste. Batteries fall into several sub-groups, based on chemical composition.  The performance and life of the battery will vary by manufacturer, but batteries with the same basic chemical composition share many characteristics.

Lead-acid batteries are your traditional car batteries. They are also used in other applications where weight and size are relatively unimportant, like emergency lighting systems and wheelchairs. Lead-acid batteries actually have a liquid electrolyte solution, so are heavy and must be treated carefully.

Alkaline batteries are most commonly found in the traditional sizes of AA, AAA, C, D, etc. These batteries come in both disposable and rechargeable forms, the disposable kind being the cheapest. The rechargeable version tends to have a low-discharge rate (producing less power at a time) so is best used in low-energy devices like clocks.

Nickel-metal hydride (NiMH) batteries are also available is traditional sizes (AA, C, D). They are rechargeable and have a high-discharge rate, so are good for use in electronic devices like digital cameras. They are now used in hybrid cars instead of lead-acid batteries because of their lighter weight and smaller size.

Lithium-ion batteries are mostly used in cell phones, laptop, and notebook computers. They are lightweight and rechargeable, but can also be fragile. Lithium-ion polymer (LiPo) batteries are pretty much the same, but can be packaged in a wider variety of sizes and shapes.

Nickel-cadmium (NiCad) batteries have a long shelf life and a high discharge rate, but low energy density. They are often used in 2-way radios, power tools, and professional cameras. These batteries are, however, quite toxic and must be disposed of properly. NiMH batteries are largely replacing NiCad batteries in consumer products.

Button batteries are small, disposable batteries most commonly made using zinc or lithium. You’ll find them in wristwatches, calculators, and other small electronic devices.


Recharging reverses the chemical reaction in the battery, allowing the electricity-producing reaction to happen over and over again. The battery can keep producing electricity until it eventually wears out.

A rechargeable battery has a limited number of charge cycles. It is not an exact number, but the following table can give you a rough guideline of what to expect from different types of batteries:

*These are average numbers and may vary depending on manufacturers, as well as the use the battery will undergo.

From the purchase of a battery to its eventual expiration, the life of the battery and amount of use you get can vary widely depending on the type of battery, storage, and usage. How you use your batteries can either extend or diminish the life of the battery.

To get the most out of your batteries, follow a few easy steps:

  • Use the right type of battery for the device.
  • Turn off devices when they aren’t being used.
  • For items that are used infrequently, remove batteries between uses.
  • For rechargeable batteries, don’t leave them on the charger once they’ve been fully charged; they lose a percentage of their capacity if left on the charger too long.
  • Store unused batteries at or below room temperature.


Depending on the composition of the battery, the recycling process varies. Other batteries are too small and delicate for such recycling, so batteries like Lithium-ion are shredded and turned into other products, like industrial lubricants. Other batteries are not as valuable to reclaim, but still have components that are worth salvaging, and remaking either into new batteries, or into other products.

The Recycling Process

First, the batteries are sorted by chemistry. Each type of battery requires a different process to separate and reconstitute the individual components.

In the case of lead-acid batteries acid solution, the plastic, lead and other components are all separated. The lead is melted, purified, and remolded for use in new batteries. The acid solution is neutralized, filtered, and reconstituted to use in new battery cells. The plastic is also refurbished and made into new battery casings.

Lead-acid batteries have been consistently recycled for decades, thanks to the organization of the auto industry in reclaiming used batteries. Between 98% and 99% of lead-acid car batteries are recycled and remade into new batteries.

For other battery types, the components are also separated, and in some cases remade into new batteries, but can also be made into other products. Lithium batteries, for example, are frozen with nitrogen to neutralize the lithium, before the batteries are crushed and shredded. The lithium is then separated and rendered non-reactive before being sold to produce lubricating greases. The cobalt in the battery is also separated and sold for reuse.

Where can I recycle my batteries?

Many retailers will accept batteries for recycling that have been purchased in-house, and more and more retailers and depots now take batteries for recycling.

To find out how and where to recycle your batteries, check out:

In Canada, the annual recycling rate of batteries (other than car batteries) was less than 20% as of 2009. The good news is that Canada has the infrastructure to process and recycle all of the batteries that Canadians use each year.