The correct charging and usage of
18650 lithium batteries is something that every user needs to pay attention to. Lithium batteries are everywhere in daily life, such as mobile phones, small appliances, desk lamps, etc. Today, we will share with you the correct charging and usage methods of lithium batteries from manufacturers of polymer physics batteries and 18650 batteries.
1、 Charging of lithium batteries
The currently considered correct lithium battery charging algorithm is "measuring battery voltage - above 3V (if it is below 3V, charge with a small current to 3V) - normal charging - charging to 4.2V (with an allowable error of 5%) or charging current below 0.01C - cut-off. A truly intelligent charger mainly measures whether the current is automatically adjusted according to the battery voltage at the beginning and whether it is cut-off after being fully charged. More complete chargers also add temperature monitoring, time monitoring, current monitoring, etc. when judging whether it is fully charged. Samsung charging is very good in this regard, and those who like it can tinker with it, but there is no perfect solution to the problem of the four hour limit.
Common charging methods
High voltage charging: This charging method does not have a dedicated control circuit, and directly uses a 5V power supply head (or a diode in series to reduce voltage) to charge the battery with a protective board, relying entirely on the high voltage limit of the protective board. The characteristic is that the current is high at the beginning, then gradually decreases, and float charging is available at any time; Most of the things that will explode are this, commonly seen in low-end card insertion MP3 players, high-end ones that cannot be afford, I don't know - I dare not say "such an expensive machine should have a charging circuit" - there are many things that should be done, but there are more things that should be done but not done
Constant voltage charging: This method is similar to the previous one. Constant voltage is actually "voltage limiting", setting a relatively precise maximum voltage, and then charging to that voltage without stopping until it reaches 4.2V, which is called "stupid charging" by the public. If the cut-off voltage of this charger is made very accurate, it is safe if it is too low. If it is too high, it still needs to rely on the protection board. As for bare batteries, they should seek more blessings on their own. Commonly seen in today's mobile phone universal charging and flashlight direct charging, this type of charger costs less than one yuan and is made up of inferior parts. Its retail price on Taobao ranges from 2.00 to 15.00 yuan. How long it can be used depends on your character. If you often help the elderly cross the street, it may take longer to use, and if you can't stick it up, it may smoke when plugged in.
Constant current charging: This method is still derived from the previous and previous circuits, but with a limit on the maximum charging current. Constant current and constant voltage are actually "current and voltage limiting", which can be considered as the son of silly charging - silly is inherited - so he is still a fool. This type of circuit is quite popular, such as Nanfu and Xinyu. After being fully charged, it is not completely cut off and instead uses trickle float charging - now it is believed that long-term low current charging is one of the reasons for battery bloating
Intelligent charging: This is currently considered an ideal charging management method, following the charging algorithm mentioned at the beginning of this section, integrated into a small chip IC, with simple peripheral circuits, stable and reliable, such as TP4054/4055/4056/4057, TP4002/5000, MAX1879, and so on. The main feature of this chip is that it monitors both voltage and current when determining whether it is fully charged. It stops charging at 4.2V or when the charging current is less than 0.01C (usually around 50mA); Completely cut off after being fully charged, without trickle or float charging, but monitor the voltage at any time. If the battery voltage drops to a certain value, start charging again
The correct method for
lithium batteries
In summary, my most important tip on the charging and discharging issues of lithium batteries during use is:
1. Charge according to standard time and procedures, even for the first three times;
2. When the battery level is too low, it is advisable to start charging as soon as possible;
3. The activation of lithium batteries does not require special methods, and they will naturally activate during normal use. If you insist on using the widely circulated "first three 12 hour long charging activation" method, it will not actually be effective.
