Li-Ion (lithium-ion battery) is a separate battery installed in many phones, laptops, tablets, and other equipment. Take the laptop battery as an example. It may look like a plastic block. In fact, inside the so-called block, there are several batteries of size 18650. Outwardly, they look like regular AA batteries.
The rated voltage of the lithium-ion cells is 3.7 volts. However, you can find a value of 11.1 volts on larger batteries. This indicates that such a battery consists of three identical cells. In addition to the cells in the plastic case, there may be a controller. It regulates the temperature level and prevents the battery from overcharging.
All Li-Ion batteries are charged with a constant current with a smooth increase in voltage. The charger switches to constant voltage mode when the voltage reaches its maximum value (for example, take a laptop battery at 11.1 volts). At the same time, the amperage gradually begins to decrease until the battery is fully charged. Lithium-ion batteries must be charged carefully without subjecting them to sudden temperature changes.
