NiMH & NiCd -- constant current
lead acid & Li Ion -- constant voltage
Especially for LiIon, but also for very fast charging of the other types you need to use an inteligent charger, that controls voltage, temperature, current and time of charging. Otherwise the battery may explode from overcharging.
All batteries can be 'Constant Current' charged. See link on my website below.
**broken link removed**
What that means is that a battery is charged constantly with the same current. Using Ohm's law you can figure out the parameters. For example, a 12V battery at 6ah can be charge at the standard 1/10 th rate, meaning 1/10th of 6A is 600mA, charged at 12V.
There are also 'pulsed' chargers wich provide a charge pulse in reference the negative polarity.
Then there are 'temperature' chargers who charge a battery by monitoring the temperature. An example is the battery pack for a modern deWalt or Ryoby drill or circular saw and many others. Hope this helps.