Lithium battery usage and precautions

Now the mobile phone is using lithium-ion batteries, so there is no memory effect problem, also do not need to activate, the first charge does not need to be like the nickel as the impact of more than 12 hours, only need to charge about 4 hours, the life of the ion battery is only related to the number of charges, lithium-ion batteries can be charged about 1000 times. Standby time is related to usage. However, the sale of mobile phone said the first three charging time to reach 12 hours. What's going on?

1. How to charge new batteries
In the use of lithium batteries, attention should be paid to the battery after a period of time into a dormant state, at this time the capacity is lower than the normal value, the use of time is also shortened. But lithium batteries are easy to activate, as long as after 3-5 normal charge-discharge cycle can activate the battery, restore normal capacity. Because of the characteristics of lithium battery, it has almost no memory effect. Therefore, there is no need for special methods and devices to activate the new lithium battery in the mobile phone. Not only in theory, but in my own practice, the "naturally activated" way of charging from the start is the best. As for the "activation" of lithium batteries, many arguments are: charge time must be more than 12 hours, repeated three times in order to activate the battery. The term "the first three charges should last more than 12 hours" is obviously a continuation of nickel batteries such as nickel cadmium and nickel hydrogen. So this argument can be said to be misleading at the very beginning. The charge-discharge characteristics of lithium and nickel batteries are very different, and it is very clear that all the serious formal technical data I have reviewed emphasize that overcharge and overdischarge can cause great damage to lithium batteries, especially liquid lithium-ion batteries. Therefore, it is better to charge according to the standard time and standard method, especially do not charge for more than 12 hours. Usually, the charging method introduced in the instruction manual is suitable for the standard charging method of the mobile phone. In addition, the mobile phone or charger of lithium batteries will automatically stop charging after the battery is full, there is no nickel charger so-called "trickle current" charge lasting more than 10 hours. That is to say, if your lithium battery is full, it will also be charged on the charger. None of us can guarantee that the characteristics and quality of the battery's charge-discharge protection circuit will never change, so your battery will be in danger for a long time. This is another reason why we are opposed to long charging. In addition to some mobile phones, after charging for more than a certain period of time, if you do not remove the charger, this time the system not only does not stop charging, but also will start discharging-charging cycle. Maybe the manufacturers of this approach have their own purposes, but obviously it is not good for the life of batteries and cell phones / chargers. At the same time, long-term charging takes a long time, often need to be carried out at night, and in China's power grid situation, many places at night the voltage is relatively high, and volatile. As has been said before, lithium batteries are very delicate, and they are much less resistant to fluctuations in charge and discharge than nickel batteries, thus creating additional hazards. In addition, another aspect that can not be ignored is that lithium batteries are also not suitable for overdischarge, overdischarge is also unfavorable to lithium batteries. This leads to the following questions.

2. When should the normal use of the battery start charging in our forum, we can often see this statement, because the number of charges and discharges is limited, so the battery should be charged as much as possible with light. But I found an experimental table about the charge-discharge cycle of lithium-ion batteries. The data about the cycle life are listed below.
Cycle life (10%DOD): >1000 times.
Cycle life (100%DOD): >200 times.
DOD is the abbreviation for depth of discharge. As can be seen from the table, the number of charges is related to the discharge depth, and the cycle life of 10% DOD is much longer than that of 100% DOD. Of course, if the relative total capacity of the actual charge is 10%*1000=100, 100%*200=200, the latter's full charge and discharge is still better, but the former netizen's statement needs to be revised: under normal circumstances, you should reserve the charge according to the principle of recharging the remaining battery, but if you The battery should start charging in time when you don't expect it to last through the day on the second day, regardless of whether you're willing to carry the charger to the office. And when you need to recharge in anticipation of an important event that will lead to heavy traffic, even if the battery has a lot of spare power, you just charge ahead, because you don't really lose the "1" charge cycle life, or "0.x" charge cycle life, and often this x will be very small. The principle of battery recharge is not to go to extremes. As popular as long-term charging is the phrase "try to use up the battery of your cell phone, and it's best to use the automatic shutdown". It's actually just a nickel battery approach, designed to avoid memory effects, which unfortunately have been circulating on lithium-ion batteries. There have been instances of people continuing to use their phones until they shut down automatically without recharging after warnings of low battery power. As a result, the phone in this case did not respond to subsequent charges or boots and had to be sent to customer service for repair. This is actually due to the battery due to excessive discharge and lead to low voltage, so that do not have the normal charging and startup conditions.

3, the right way to lithium cell phone.
To sum up, the most important hints for charging and discharging of lithium battery phone in use are:
1, charging according to the standard time and procedure, even if it is the first three times.
2, when mobile phone power is too low, it should be charged as soon as possible.
3. Activation of lithium batteries does not require special methods. Lithium batteries will activate naturally during normal use of mobile phones. If you insist on using the popular "first three 12-hour long charge activation" method, it won't actually work. Therefore, all the pursuit of 12-hour ultra-long charging and the use of lithium-ion battery handsets to shut down the practice of automatic, are wrong. If you used to do it according to the wrong statement, please correct it in time. It may not be too late. Of course, the protection of lithium batteries is guaranteed under the condition of good quality of the protection and control circuit of the mobile phone and battery charger. Therefore, the understanding of charging rules is the key point, and in some cases, we can make some concessions. For example, if you find that your cell phone must be recharged before you go to bed at night, you can also start charging before going to bed. The point is, you should know what the right thing to do, and don't deliberately follow the wrong words.