The Limited Life of a Battery

Even when not used in a device, primary batteries lose charge over time in a process known as self discharging. This rate of loss typically increases with increasing temperatures. As a result, refrigeration can be used to extend battery life, though cells must be returned to typical ambient temperatures to maximise performance. Secondary batteries suffer the same self-discharging fate even more rapidly than primary batteries, with modern lithium batteries being the best rechargeable battery at holding charge.