When long storage is required, reserve batteries are often used, since the active chemicals of the cell are segregated until needed, thus reducing self-discharge.
Reserve batteries are mostly used in missiles projection, bomb fuzes and various other weapon systems.
These batteries are used in radiosondes, missiles, projectile and bomb fuzes, and various weapon systems.
Reserve batteries remain uncommon in civilian applications because of their higher cost and relatively short life after activation.
In ordnance, the batteries are activated by acceleration during gun firing, or by spinning the projectile in flight.