Ensuring LISB reliability and safety
Overcharge and overdischarge protection is ensured by an electronic device, which is absolutely reliable in management.
Internal short circuit is prevented structurally by separator wrapping (packaging) around the electrodes and by using between the electrodes a three-ply separator, which loses its porosity (melts) upon reaching a critical temperature, and stops the electrochemical process.
Failed or anomalously degraded cells are excluded from the circuit by means of bypass switches.
The basic requirements that apply to a bypass switch for the Li-Ion storage batteries for spacecraft are the following: reliability, minimal energy loss, minimal mass, maintenance of LISB circuit continuity at switching, and mechanical and irradiation stability.
Scheme of bypass switch connection and time diagram of bypass switch operation ensure circuit continuity maintenance, when switching the cells’ circuit in the storage battery.
Thus, the failure of any cell does not lead to LISB failure. LISB reliability is also ensured by comprehensive qualification (including life tests) and strict control during manufacturing.