A solar battery is one that receives its energy from the sun or from some other light source through the use of photovoltaics. In most cases, a solar-powered battery is implanted in an electronic device and not capable of being removed. A solar battery is usually capable of fully charging after just an hour or two of exposure to sunlight.
The surest evidence of a solar battery is an array of solar cells, usually in a line or perhaps in a block, somewhere on the device. These cells collect the light and cause electrons in semiconductors to begin to move along that semiconductor and to metal contacts. Once at these metal contacts, the energy generated can then be stored in a solar battery, or it may be put to direct use.
If that energy is stored, the solar battery will discharge it at the appropriate time. For example, that time may be when it is turned on by a person, or it may come on automatically, as with some lighting applications. The power is then drawn from the solar battery much like it would be any other battery.