The negative pole is on the top and the positive pole on the slightly wider bottom. The plus side often shows the brand and type number; this side is almost always on top when inserting the battery.
There are various types of rechargeable batteries. They are usually built into the various devices. They are rarely available in shops, partly due to the low demand.
The maximum permissible temperatures for a battery are -55° and +125° Celsius. However, the best working environment for most cells is one where temperatures are between +10° and +35° Celsius. Procell is an example of a brand that offers button cell batteries.
Lithium batteries last a very long – up to ten years – even when they are hardly used at all. The self-discharge per year is only 1% of the capacity. Procell is an example of a brand that offers button batteries.