A rechargeable battery, also called a storage battery or a secondary cell, is a battery that can be recharged (refilled) over and over again with electricity. A battery that is not rechargeable is called a primary cell or disposable battery (A battery that is thrown in the garbage when it can not be used anymore). Rechargeable batteries can be recycled.
Rechargeable batteries are sometimes better than disposable batteries. They can be reused many times before being thrown away. They make less pollution because of this. Reusing them can cost less money since they can be used over and over.