6 operational misconceptions about battery charging and discharging.
Activation of new batteries
Misconception: New batteries should be activated through cyclic charging and discharging to improve their performance.
The truth is: to be precise, the above statement is not a rumor. There is a time difference between the production of lithium batteries and the hands of users, ranging from as short as one month to as long as six months. For batteries with long time differences, their electrode materials will become passivated. Therefore, manufacturers recommend that first-time use batteries undergo 3-5 complete charge and discharge processes to eliminate electrode material passivation and achieve maximum capacity. But usually manufacturers do not pay attention to reminding consumers that the full charge and discharge referred to here should not be deep discharge, but should be controlled within 5% to 8%. Otherwise, a new battery is likely to be scrapped.
The first three charges
Misunderstanding: After buying a new battery, it is best to perform three cycles of charging and discharging, with a charging time of more than 12 hours, in order to activate the battery's maximum efficiency.
The truth is: in order to achieve the most perfect saturation state, nickel hydrogen batteries need to go through a "replenishment" and "trickle down" process, which usually takes about 5 hours. At present, the "constant current" and "constant voltage" charging characteristics of lithium-ion batteries control their deep charging time within 4 hours. Once fully charged, the protective circuit inside the battery will automatically stop charging, so this approach is neither scientific nor practical.
Someone has conducted experiments using a mobile phone before. After fully charging the battery with a travel charger, switch to a seat charger to confirm the saturation level of the battery. When he found that the seat 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 base charger is not the only criterion for detecting true saturation. The reference voltage of the base charger may not be equal to the reference voltage of the phone. Therefore, when the phone believes that the battery has reached saturation, the base charger may not think so and still charge, but whether it has been charged or not is only known by itself.
best condition
Misconception: As long as the rechargeable battery is used properly, it will reach its optimal state and maximum capacity within a certain cycle range.
For example, early nickel hydrogen and nickel cadmium batteries, if used properly and maintained regularly, would reach their maximum capacity in 10-200 cycle points (a nickel hydrogen battery with a factory capacity of 1000mAh may reach 1100mAh after 100 cycles).
The truth is that this statement is quite common in Japanese battery products, and can usually be seen in the cycle characteristic diagram in their technical specifications. However, for current mainstream lithium-ion batteries, this cyclic peak phenomenon does not exist. Because the capacity of lithium-ion batteries is reduced by one cycle from factory to disposal, there has never been a phenomenon of capacity recovery. Perhaps some friends may ask that some ThinkPad laptop users can restore battery capacity through deep discharge. In fact, it was just an error detection of the testing software, and the actual capacity of the battery did not increase at all.
Is there an optimal state for lithium-ion batteries? The answer is yes, it is related to the changes in environmental temperature it experiences. In general, lithium-ion batteries exhibit excellent performance in environments ranging from 25 ℃ to 40 ℃. At low or high temperatures, its performance will be greatly reduced. For example, if you use a laptop in direct sunlight outdoors, you won't spend as much time indoors.
capacity
Misconception: For two batteries with the same nominal capacity (e.g. 800mAh), if one actually measures 860mAh and the other 805mAh, then 860mAH is definitely better than 805mAh.
The truth is: generally speaking, the higher the capacity of lithium-ion batteries of different models (different volumes), the longer their usage time. If we set aside factors such as volume and weight, of course, the higher the capacity, the better. But it may not be the case for two batteries with the same nominal capacity (as in the example above). Because the battery with high actual capacity is likely to have added substances to the electrode material to increase the initial capacity and reduce the substances used to stabilize the electrode. The result is manifested in the rapid decay of the high-capacity block after dozens of cycles, while the high-capacity block remains firm. Many domestic manufacturers often use this method to produce high-capacity batteries in order to reduce costs and expand sales. After using it for six months, users will find that their working hours have been greatly reduced. In short, the cost of increasing capacity is sacrificing cycle life. Manufacturers cannot truly increase battery capacity without focusing on the materials used in the battery.
Storage of batteries
Misconception: If a rechargeable battery is not in use, it should be discharged before storage.
The truth is: not only are there rumors mentioned above, but whether lithium-ion batteries should be fully charged for storage or fully discharged for storage will definitely confuse many people? The answer to this question starts with its congenital defect, which is the "aging effect". After being stored for a period of time, even if not recycled, some of the capacity of lithium-ion batteries will be permanently lost, because the positive and negative electrode materials of lithium-ion batteries begin their depletion process from the factory. The magnitude of aging varies at different temperatures and saturation levels, as shown in the table.
From this, it can be seen that the higher the storage temperature and the more fully charged the battery, the greater the range of capacity. Therefore, for long-term storage of lithium-ion batteries, users should control their battery capacity at 40% and store them at temperatures of 15 ℃ or even lower. As for those nickel hydrogen and nickel cadmium batteries, there is no such "aging effect", and after long-term storage, they only need to be fully charged and discharged a few times to restore their original capacity.
Fully charged and subsequent charging
Misconception: When charging the battery, charging it fully and then continuing for 12 hours is beneficial for enhancing the saturation of the battery.
The truth is: in general, a qualified charger will automatically turn off the charging circuit after charging is complete, with no current, even if the battery is left for another 10 hours, it will be useless. Currently, the vast majority of mobile phone chargers adopt this design. Therefore, when the green indicator light is on, simply remove the battery and use it.
