Calculation of Lithium Battery Charging Time and Charging Analysis

1. The nominal voltage of the lithium battery is 3.7V (3.6V), and the battery charging cut-off voltage is 4.2V (4.1V, according to the brand of the lithium battery cell has a different design). 2. Lithium battery charging method: First, constant current charging, that is, the charging current must be, and the voltage of the lithium battery gradually increases with the charging process. When the battery terminal voltage reaches 4.2V (4.1V), change the constant current charging to constant voltage charging. That is to say, the voltage must be determined, and the current will gradually decrease as the charging process continues according to the fullness of the battery cell. When it decreases to 0.01C, the charging is considered to be stopped. (C is a method of claiming the nominal capacity of the battery against 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. 0.01C is 10mA.) Of course, the standard statement method is 0.01 C5A, I simplified it here. 3. Why do you think that 0.01C is the completion of charging: This is the rule of the national standard GB/T18287-2000, and it is also a comment. In the past, we used 20mA as the end. The industry standard YD/T998-1999 of the Ministry of Posts and Telecommunications is also the rule, that is, no matter how large the battery capacity is, the stop current is 20mA. The 0.01C of the national standard will help the charging to be fuller, which is beneficial to the manufacturer's judgment. In addition, the national standard stipulates that the charging time should not exceed 8 hours, that is to say, even if it has not reached 0.01C, 8 hours will be considered to be fully charged. (Batteries with no quality problems should reach 0.01C within 8 hours, and batteries with poor quality will not make sense to wait.) 4. How much charging current is appropriate: in theory, the smaller the battery, the more advantageous it will be. But you can't wait 3 days to charge a battery. The low-rate charging specified by the national standard is 0.2C (ruled charging system). Taking the above 1000mAh battery as an example, it is 200mA. Then we can predict that this battery can be fully charged in more than 5 hours. The fault statement about lithium battery charging: Because the number of charging and discharging is limited, the battery of the mobile phone should be used up as much as possible to recharge. Under normal circumstances, you should reserve and charge the lithium battery according to the principle of recharging when the remaining power of the lithium battery is used up (but certainly not when shutting down and recharging). It is assumed that your battery will not last the entire day on the second day of your estimation. You should start charging in time when you want to charge! And when you want to charge to deal with the important things that will lead to busy communication, even when the battery has a lot of remaining power, then you just need to charge early, because you are not really real. Lost a charge cycle life! The criterion for recharging when the remaining battery is used up is not to make you go to the extreme. It is widely believed that the charging time of a lithium battery is the same as a long charge, which is to use up the battery of the mobile phone as much as possible, and it is best to use the automatic shutdown. This approach is actually only done on nickel-cadmium batteries, and the intention is to guard against the occurrence of the memory effect. Unfortunately, it has also spread on lithium batteries to this day. In the past, some people did not charge after the warning that the battery of the mobile phone was too low, and continued to use the automatic shutdown, such as the one that has always been used. As a result, the mobile phone in this example showed no response during subsequent charging and booting, and had to be sent for inspection. In fact, this is because the battery voltage is too low due to over-discharge, so that it does not have normal charging and starting conditions. The relevant experience of the test has proved that the scrap rate of lithium batteries with a discharge depth of 100% is 50% (years of facts have proved that the lithium battery repair power supply with a discharge depth of more than 99% can be activated only in half, and the other half is scrapped!) Know that the lithium battery is charged Time, in terms of difficulty, operation is not a big problem. Knowing the origin of lithium battery charging time is more helpful to make it more scientific in theory and practice. Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: Lithium battery pack protection board balanced charging and principle analysis