The period a battery can be stored (typically at ~15°C) without significant loss of performance or safety.
Self discharge of cells is dependent on the chemistry, temperature and age of the cell. These reactions occur in any electrochemical systems and are very difficult to avoid completely. This is because some self discharge reactions involve chemical reactions which will always take place at a rate proportional to temperature.
Needs review: This page is a stub. It could be expanded to cover recommended storage state-of-charge ranges, standard storage-life test requirements (e.g. UN 38.3, IEC 62660 series), and how storage temperature quantitatively trades off against shelf life — left for a proper pass with sourced figures rather than invented numbers.