Button cell

A button cell usually a single cell, lithium or silver-oxide based battery. The larger lithum-based cells are also known as "coin cells" as they are similar in size.

Scope of application

• LCD wrist watch quartz watches
• calculators
• small pda devices
• some remote controls
• tiny toys (tamagotchi)
• backup of personal computer configuration data.
• Low-end quartz watch (most likely powered by a silver-oxide cell).
• Laser pointers
• LED lamps are commonly powered by three button (sliver-oxide) cells in series.

Lithium based

typical lithium button cell

This type (Lithium battery) provides 3 volts.
Modern quartz watches, calculators and small pda devices are commonly powered by this type.

rechargeable

This type is not widespread, sometimes three (larger) button cells are connected in series.
Rechargeable Button cells do not have good capacity performance.
Suitable chargers are not commonly available.

other chemical composition

• Mercury cells are now banned from sale in many countries.
• Alkali cells are sometimes found in low-end markets, but do only provide a fraction of capacity.
• Silver-oxide cells are not toxic, and have replaced mercury based cells.
• Zinc-oxide cells are utilizing air (it is required to remove a plastic foil layer before usage).

other types

9 volt batteries commonly contain "tablets" in button cell style, or an array of six tiny button cells.
For this reason the alkali versions are remarkable expensive.
Some special 12 volts batteries (remote controls) are also composed of tiny button cells.