Analyze the basic knowledge of mobile phone lithium batteries

Analyze the basic concept of mobile phone lithium battery The current mobile phones are basically equipped with lithium batteries, so the following is the knowledge about lithium battery charging. Ni-MH batteries are different. 1. The nominal voltage of the lithium battery is 3.7v (3.6v), and the charging cut-off voltage is 4.2v (4.1v, according to the different design of the battery brand). (Lithium battery specification is: lithium ion secondary battery) 2.Lithium battery requirements (GB/T182872000 specification): First, constant current charging, that is, the necessary current, and the battery voltage charging process are gradually added, when the battery voltage is 4.2V (4.1V), constant voltage charging, not constant current charging voltage must be current according to the saturation of the battery, the charging process continues to gradually decrease, when it is reduced to 0.01 degrees Celsius, it is considered that the charge is terminated. (C is a way to express the ratio of the nominal capacity of the battery to the current. For example, if the battery capacity is 1000mAh, then 1C is the charging current 1000mA. Note that it is mA instead of mAh. Of course, the specification is 0.01c5a, I Simplified here. 3.0.01℃ is regarded as the reason for the end of charging: this is stipulated in the national standard GB/t18287-2000 and discussed. In the past, it usually ends at 20mA. The industry standard of the Ministry of Posts and Telecommunications YD/ t998-1999 also stipulates that regardless of the battery capacity, the stop current is 20mA. The national standard of 0.01C is conducive to more adequate charging, and passing the assessment is conducive to manufacturers. In addition, the national standard stipulates that the charging time should not exceed 8 hours, that is, even if If the battery does not reach 0.01c, it is regarded as the end of charging. (If the battery quality is good, it should reach 0.01c within 8 hours. If the battery quality is poor, waiting is meaningless. 4. How to distinguish whether the battery is 4.1v or 4.2v: consumption It depends on the battery manufacturer’s product specifications. Some brands of batteries are 4.1v and 4.2v in general, such as Au0026TB (Toshiba), while domestic manufacturers are basically 4.2v, but there are exceptions. For example, Tianjin Electric Power God is 4.1v v (but also 4.2v). 5. What happens when you charge a 4.1v battery to 4.2v: the battery capacity will increase, it is very convenient to use, the standby time will increase, but the battery life will be shortened. Assume from 500 To 300. Similarly, if the 4.2v battery is overcharged, the service life will be shortened. The lithium battery is very fragile. 6, because of the battery protection board, can we rest assured: No, because the cut-off parameter protection board is 4.35v (this is still It's good, poor 4.4 to 4.5v), if the protective plate is processed, the battery will decay quickly every time it is charged. 7. Appropriate charging current: In theory, the less the charge, the better the battery. But You can’t wait for three days to charge a battery. The national standard requires a low charge rate of 0.2c (arbitration charging system), and a battery with a capacity of more than 1000mAh is 200mA, so we can expect that the battery can be fully charged in more than 5 hours (Capacity mAhu003dcurrent mA×time h) The national technical supervision department has determined the lithium battery capacity, charging is 1C high, discharging is 0.2c, and the capacity value is calculated according to time. The number of tests is 5 times, and the capacity reaches the end of the test once. (That is, there are 5 opportunities. If the first test is qualified, the next 4 will not be done.) A pre-cycle is allowed before the test, that is, with 1c constant current charging, 4.2v and stop, but There is no follow-up process of constant voltage to 0.01c, 14 hours less. 8. How much charging current can the lithium battery withstand: The manufacturer's test can be very high, but the national standard multiplier is specified as 1C. The battery can withstand such a large charging current Is it? Regarding the current lithium battery, this is only a small number. There is currently no national charger standard, but the industry standard of the Ministry of Post and Telecommunications is YD/T9981999/2. The current of the charger should not be greater than 1C. 9. What is the life expectancy: Simply put, the capacity of the battery drops to 70% after N times of 1C charging and 1C discharge. At this time, N is the lifespan. It's not that you can use it 300 times, nor that you can't use it 301 times. National standards stipulate that the service life shall not be less than 300 times. The conditions we usually use are not as harsh as they are, and we live longer. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Why do electric vehicles use lithium batteries as energy sources?