Generally there are three most popular charging ways as below:
1-CC charging(Constant current)
The charging current keeps the same at a certain amount during the whole charging process, Most rechargeable batteries charge this way.
2-CV charging(Constant voltage)
The voltage for both ends of the power supply keeps at a certain value, while the charging current goes down with the rise of battery voltage.
3-CC CV(Constant current and Constant voltage)
The battery charge with CC constant current mode at first, when the battery voltage rises up to a certain level, the voltage keeps the same, and the charging current lowers down slowly and ends up with 0.
The first and second ways, are mostly used for NiMH and NiCd batteries, the third way is always used for lithium ion battery, lithium polymer battery and LiFePO4 battery, the CC CV charging mode is designed to protect the battery from over charging as a reliable charging way.