Button cells maybe also be known as coin cells or watch batteries.
The insulated top cap of a button cell is the negative terminal, the base is the positive terminal.
The internal resistance of a coin cell battery starts of at a rather large 10Ω. This then rapidly increases as the batteries energy is consumed. Where high pulse currents are needed, coin cell batteries can be used in conjunction with high-valued capacitors.
A rule of thumb for coin cell batteries is that 10mA is the maximum current draw.
Silver cells have a very stable output voltage over the lifespan of the battery.