6 major operating misunderstandings about battery charging and discharging

Activation of new battery
Misconception: New batteries should activate battery performance by cycling charge and discharge.
The truth is: to be precise, the above statement is not a rumor. There is a time lag between lithium batteries leaving the factory and reaching users, which can be as short as one month or as long as half a year. For batteries with a long time difference, the electrode material will be passivated. Therefore, the manufacturer recommends that the first-time battery be fully charged and discharged 3 to 5 times in order to eliminate the passivation of the electrode material and reach the maximum capacity. But usually manufacturers fail to remind consumers that the full charge and discharge mentioned here should not be deep discharge, but should be controlled at 5% to 8%. Otherwise, a new battery is likely to become useless.

"First three" charging
Misconception: After buying a new battery, it is best to perform three cycles of charge and discharge. The charging time should be more than 12 hours in order to activate the maximum performance of the battery.
The truth is: in order to reach the most perfect saturation state, nickel-metal hydride batteries need to go through a "replenishment" and "trickle" process. This time is usually about 5 hours. The current "constant current" and "constant voltage" charging characteristics of lithium-ion batteries control their deep charging time to within 4 hours. Once fully charged, the battery's internal protection circuit will automatically stop charging, so this approach is unscientific and has no practical significance.
Someone once did an experiment with a mobile phone. After using the travel charger to fully charge the battery, use the dock charger to confirm the saturation level of the battery. When he noticed that the cradle charger was still charging the battery, he assumed that the battery had not yet reached saturation. In fact, this testing method lacks rigor. The reason is that the indicator light of the cradle charger is not the only criterion for detecting true saturation. The base voltage of the cradle charger is not necessarily equal to the base voltage of the mobile phone. Therefore, when the mobile phone thinks that the battery has reached saturation, the cradle charger Maybe it doesn't think so, and it still charges, but only it knows whether it is charged in or not.

Best state
Misconception: As long as the rechargeable battery is used properly, it will appear in its best state and reach its maximum capacity within a certain cycle range.
For example, early nickel-metal hydride and nickel-cadmium batteries, if used properly and maintained regularly, will reach their maximum capacity in 10 to 200 cycle points (the capacity of a nickel-metal hydride battery with a factory capacity of 1000mAh may increase after 100 cycles). up to 1100mAh).
The truth is: This statement is relatively common in Japanese product batteries, and can usually be seen in the cycle characteristic diagrams in their technical specifications. However, for current mainstream lithium-ion batteries, this cycle peak phenomenon does not exist. Because the capacity of lithium-ion batteries from the time they leave the factory to the time they are scrapped is one cycle less, and there has never been a capacity recovery. Some friends may ask, some ThinkPad notebook users can restore battery capacity through deep discharge. In fact, it was just an error detection by the test software, and the actual capacity of the battery was not increased at all.
Are lithium-ion batteries ever in optimal condition? The answer is yes, it is related to the changes in ambient temperature. Generally, lithium-ion batteries will show excellent performance in an environment of 25℃~40℃. At low or high temperatures, its performance will be greatly compromised. For example, if you use your laptop outdoors in direct sunlight, it won't last as long as it does indoors.

Capacity
Misconception: For two batteries with the same nominal capacity (for example, 800mAh), if one actually has a measured capacity of 860mAh and the other is 805mAh, then the 860mAH one must be better than the 805mAh one.
The truth is: Generally speaking, the higher the capacity of lithium-ion batteries of different models (different sizes), the longer they can be used. If factors such as volume and weight are put aside, of course the higher the capacity, the better. But this may not be the case for two batteries with the same nominal capacity (such as the example above). Because the actual capacity of the battery is high, it is likely that substances used to increase the initial capacity are added to the electrode material and substances used to stabilize the electrode are reduced. The result is that after dozens of cycles, the piece with high capacity decays rapidly, while the piece with low capacity remains strong. In order to reduce costs and expand sales, many domestic manufacturers often use this method to produce high-capacity batteries. Users will find that their working time is greatly shortened after half a year of use. In short, the cost of increasing capacity is sacrificing cycle life. It is impossible for manufacturers to truly increase battery capacity without considering the materials of the battery.

Battery preservation
Misconception: If rechargeable batteries are not used, they should be discharged before being stored.
The truth is: In fact, not only the rumors mentioned above, whether the lithium-ion battery should be stored full or discharged will definitely confuse many people? The answer to this question starts with its congenital defect, which is the "aging effect." After a lithium-ion battery is stored for a period of time, even if it is not recycled, part of its capacity will be permanently lost. This is because the positive and negative electrode materials of the lithium-ion battery have begun their depletion process since they left the factory. The aging amplitude is also different under different temperatures and saturation levels. The specific amplitude can be seen in the table.
It can be seen that the higher the storage temperature and the more fully charged the battery, the greater the capacity range. Therefore, for long-term storage of lithium-ion batteries, users should control their power to 40% and store them at a temperature of 15°C or even lower. As for those nickel metal hydride and nickel cadmium batteries, this "aging effect" does not exist. After long-term storage, only a few full charges and discharges can restore their original capacity.

Recharge after full charge
Misconception: When charging the battery, recharge it for 12 hours after it is fully charged. This will help enhance the saturation of the battery.