Battery and battery are two different concepts
For most ordinary lithium batteries, such as mobile phone batteries, laptop batteries and camera batteries, This is a battery + protective plate and case. Or the outer skin, this is a complete lithium battery. Needless to say, the function of the battery core is to store electricity. The main function of the protection plate is to protect the battery from overcharging (overcharge), exhaustion (over-discharge) or death. (short circuit)" to extend the life and safety of the battery
Disassemble the battery. In addition to the protection board (circuit), there is the battery. The battery of a cell phone battery is usually These are lithium-ion batteries in an aluminum casing, and there are also lithium polymer batteries that useUsually use 18650 lithium-ion batteries, and a few use other batteries as well; Ordinary card camera batteries are similar to cell phones. These are also flat square lithium batteries. Large cameras such as SLRs use different types of cylindrical lithium batteries.
Regarding the battery cell structure, this was answered by user 92734923. Whether we ordinary people know it or not doesn't mean much