Rechargeable lithium-ion battery is the most widely used battery in modern digital products (such as mobile phones and laptops), but it is more "exquisite" and should not be overcharged or overcharged during use. Therefore, the protection component or protection circuit on the battery can prevent expensive battery damage.
Lithium ion battery charging has high requirements. In order to ensure the accuracy of termination voltage within ± 1%, major semiconductor device manufacturers have developed various lithium-ion battery charging ICs to ensure safety Reliable and fast charging.
Mobile phones basically use lithium-ion batteries. According to the requirements of different electronic products, it can be made into flat rectangular, cylindrical, rectangular and button types, and the battery pack is composed of several batteries connected in series and parallel.
Lithium ion batteries with lithium cobalt oxide as cathode are not suitable for high current discharge. When the discharge is excessive, the discharge time will be reduced (higher internal temperature will be generated and energy will be lost), and there may be danger; The positive material lithium battery can be charged and discharged at a high current of 20c or higher (C is the battery capacity, for example, C = 800MAH, 1C, and the charging rate is 800mA), which is especially suitable for electric vehicles.
Lithium battery manufacturers believe that lithium battery charging is divided into two stages: first, constant current charging, and then constant voltage charging when it is close to the termination voltage. For example, the termination charging voltage of an 800MAH battery is 4.2V. The battery is charged at a constant current of 800mA (charge rate of 1c). At the beginning, the battery voltage will rise with a large slope. When the battery voltage approaches 4.2V, it will change to 4.2V constant voltage charging. The current decreases gradually and the voltage changes little. When the charging current drops to 1 / 10-50c (the factory settings are different and do not affect the use), it is considered that the charging is nearly full, and the charging can be terminated (some chargers start the timer 10C after 1 / 10 and end the charging after a certain time).
