When looking at batteries they can be split into two main categories:

Primary batteries: These are batteries that are not intended to be recharged and are to be used only once. They are supplied fully charged, and will discharged once the battery has delivered all of its electrical energy.

Secondary Batteries: These are batteries that are intended to be re-charged and re-used a number of times.

Within these categories there are many different types of battery which are generally distinguished by the chemicals used in them. In this section, battery construction is discussed along with a comprehensive list of the different types of battery available and their general applications.

Battery Shapes and Sizes

Batteries come in all shapes and sizes; the reason for this is because of the wide range of applications batteries are used for. Here is a list of the basic types of battery construction.

Cylindrical Cell

The Cylindrical Cell is the most common seen on the consumer market with the likes of AA, AAA batteries being of this type of construction. There are two types of cylindrical cell design, Bobbin, and Spirally Wound.

Bobbin Design

Most commonly used in the construction of cylindrical alkaline cells. It has an internal cylindrical terminal (electrode) usually in the form of a rod which is immersed in the electrolyte which is contained in an external electrode in the form of a cylindrical cup arranged as a sleeve inside the cell container. A separator sheath prevents contact between the electrodes.

The advantage of this design is that a large amount of electrolyte can be stored giving a high capacity and long life.

The disadvantage is that the electrolyte surfaces are very small which limits the current it can deliver and so is limited to use in low current drain devices.

Spirally Wound Design

In this design, the electrodes and the separator are made from long strips of foil, rolled into a spiral shape.

The advantage of this design is that it increases the surface area of the electrodes and hence increases the current carrying capacity of the cells.

The disadvantage is that it extra space taken up by the electrodes means that there is less space for the electrolyte and therefore the potential energy stored capacity of the cell is reduced.

This construction is used mainly for secondary (rechargeable) cells such as NiCd, NiMH and is used for high rate discharge applications.

Button Cell

This type of construction uses circular disks for its electrodes with a separator sheet in between them to prevent contact. This is then places into a nickel-plated cup and electrolyte is added with and a cap is crimped on with a gasket separating the two.

They are used when small size is required; they have a relatively high capacity but deliver low power, and are used in low current drain devices.

Coin Cell

Coin Cells are similar to Button Cells in their construction; however they are thinner and flatter than button cells. They use circular discs for the electrodes with a separator between them. This is again placed into a nickel-plated cup, with the cap crimped on; however in this case, a grommet is used to separate them making the top surface of the call much smoother than the button cell.

They have a longer shelf life than button cell batteries and have a slightly higher capacity. However they are still used in low current drain devices such as watches, calculators and memory retention equipment.

Battery Pack

Battery packs are custom made packs constructed from a number of individual cells. Most commonly they are made up of a number of cylindrical cells connected together in certain configurations to provide the appropriate characteristics. For more information, see our Custom Battery Pack section.

Battery Technology Characteristics

NOTE: The values quoted in this table are approximate values; these types of battery manufactured by different people will have slightly different characteristics. If you need the exact values, it is advisable to check the datasheets for the battery you would like to use. Also, most batteries perform better at lower temperatures, again check with your supplier.