Lithium Ion Batteries are becoming more and more popular in spacecraft, due to their high power per mass ratio. There are several companies, such as Quallion, advertising their space rated batteries. What is the proper way to charge them to optimize battery life, and prevent fires such as occurred in the Boeing 787 Dreamliner?
For example, the ISS is planning on launching them in 2016, as are several other missions I am aware of.
Although this question belongs to physics or chemistry still following is the answer you are looking for.
The typical charging protocol for the Li-Ion cells with layered cathodes includes a constant current charge to a voltage of 3.9 V to 4.2 V (depending on the metal oxide cathode and manufacturer’s recommendations) and held at constant voltage until the current falls down to approximately C/50 or C/100 (this can vary according to the manufacturer). The term, “C” signifies the charge or discharge rate, in Amperes, expressed as a multiple of the rated capacity in Ampere-hours (Ah). Due to the unique charging characteristic of the Li-Ion cells and batteries, charging requires a dedicated charger that can keep the cells and batteries within their specified voltage limits. This charger may be a “smart” charger in some cases. The discharge of the cell depends on the load used, but the end voltage during discharge should not go below 2.5 V. Typical end of discharge voltages for the batteries in different equipment has been 3.0 V/cell. Internal resistance for the Li-Ion cells varies from 9 to 120 mΩ for small (1 to 3 Ah) cells to about 0.8 mΩ for large (190 Ah) cells
this the quote from the NASA document called Guidelines on Lithium-ion Battery Use in Space Applications
