1. The nominal voltage of lithium-ion batteries is 3.7V (3.6V), and the charging cutoff voltage is 4.2V (4.1V, depending on the brand of the battery cell). (The specification for lithium-ion battery cells states: lithium-ion secondary batteries)

　　2. Requirements for charging lithium-ion batteries (GB/T18287 2000 specification): Firstly, constant current charging, which means the current is constant, and the battery voltage gradually increases with the charging process. When the battery terminal voltage reaches (), constant current charging is changed to constant voltage charging, which means the voltage is constant. The current gradually decreases as the charging process continues based on the saturation level of the battery cell. When it decreases, it is considered that the charging is terminated. (C is a representation method that compares the nominal capacity of the battery to the current. For example, if the battery has a capacity of 1000mAh, 1C is the charging current of 1000mA. Note that it is mA instead of mAh, which is 10mA.) Of course, the standard representation is simplified here.

　　3. Why is it considered to be the end of charging? This is stipulated in the national standard GB/T18287-2000 and was also discussed. Previously, it was common to end with 20mA, and the industry standard YD/T998-1999 of the Ministry of Posts and Telecommunications also stipulated that regardless of the battery capacity, the stopping current is always 20mA. According to the national standard, it helps to charge more fully, which is beneficial for the manufacturer to pass the appraisal. In addition, the national standard stipulates that the charging time should not exceed 8 hours, which means that even if it has not been reached yet, the charging is considered to have ended after 8 hours. (Batteries with good quality should be delivered within 8 hours, while batteries with poor quality are meaningless to wait for.)

　　4. How to distinguish whether a battery is good or bad: Consumers cannot distinguish, this depends on the product specifications of the battery cell manufacturer. Some brands of battery cells are compatible with general use, such as A&TB (Toshiba), which is mostly produced by domestic manufacturers. However, there are exceptions, such as Tianjin Lishen (which is currently also used).

　　5. What would happen if the battery cells were charged to a higher capacity? It would increase the battery capacity, make it feel very useful, increase standby time, but shorten the battery's lifespan. For example, the original 500 times were reduced to 300 times. Similarly, overcharging the battery cells can also shorten their lifespan. Lithium ion batteries are very delicate.

　　6. Since there is a protective plate inside the battery, can we rest assured? No, because the cutoff parameter of the protective plate is (which is still good, but it's really bad). The protective plate is just in case. If it is overcharged every time, the battery will quickly decay.

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