The correct usage method of 18650 lithium battery.
Many people have a sense of fear towards lithium batteries, but they are also helpless. Helpless because mobile phones, laptops, tablets, and other devices all require it, fearful because one day lithium batteries may suddenly carry out terrorist attacks in front of oneself: either burning or exploding. In such incidents, it is naturally related to the electrical characteristics and quality of the lithium battery itself, but it cannot be ruled out that whether the lithium battery was used correctly is also one of the causes of lithium battery accidents.
The correct usage method of lithium batteries: Lithium battery accidents:
The method is based on the characteristics of lithium batteries themselves. Therefore, we first analyze from an electrical perspective why lithium batteries explode or burn. Burning or explosion usually occurs when heat accumulates and cannot spread out, accumulates to the ignition point, or when heat accumulates to a certain extent in a certain space. As a battery, the above situation usually occurs for the following four reasons.
1. Internal short circuit (mostly in the form of a single soft package): Structural or process defects that result in the insertion of the terminal ear, insufficient clearance of the diaphragm, burrs, and folded diaphragm. Insertion of polar ears often occurs in thick batteries and structures with internal parallel connections. The insulation of the polar ear position is not in place, which can easily lead to internal acute short circuits and combustion or explosion in subsequent products or during use (internal short circuits: I personally have a deep understanding of this, and more than 2K of this type of battery were scrapped at that time, which is actually a design defect - the essence of the abnormality is: internal acute short circuits). However, this situation is almost rare now, unless there are external factors.
2. External short circuit: Explosions caused by external short circuits of batteries below 1AH are not common, usually resulting in bulging or simply burning off the terminals. Personally, I have analyzed that combustion is caused by external short circuits of power batteries or large capacity mobile phone batteries. This involves improper use by the customer - when installing the metal outer box, the ear insulation was not considered, resulting in abnormal battery smoke and combustion at the installation site; Insufficient structural fixation measures are also common in power batteries (due to inadequate consideration), which can cause damage to the external insulation protective film or connection wire skin of the battery due to shaking of the battery pack during user use, ultimately leading to short circuit combustion.
3. Overcharging explosion: This is the most dangerous and feared by businesses, but it still occasionally occurs. From what we have learned, there are two points: a、 Users do not use the matching charger as required, which damages the protective circuit, and users often charge without time limit, which is difficult to avoid; b、 If the battery combination is unreasonable and the protective board fails, it will also explode in a mess The same applies to a single battery.
4. The material of the battery itself is not up to standard. If the material is not up to standard, it may overheat under the calibrated voltage and current, resulting in accidents.
Based on the above analysis, if lithium batteries can be used correctly and the above situations can be avoided as much as possible, some methods can be summarized:
1. Frequent deep charging and discharging: Lithium batteries have almost no memory, and many friends like to use up all their battery power (protected by a protective board) before charging when using lithium electric cars or lithium digital products. In the eyes of many people, this is also a way to activate the battery. In the use of lithium batteries, the situation of recharging after running out of power is called deep charging and discharging.
In fact, deep charging and discharging is a major misconception for many people when using lithium batteries. Scientists have concluded through experiments that the number of deep charging and discharging cycles is directly proportional to the battery life under constant environmental conditions, and multiple charging and discharging cycles can lead to premature termination of battery life. Lithium batteries that have reached the end of their long lifespan are prone to swelling and other issues, which can lead to explosions.
2. Overcharging and discharging, as well as excessive charging and discharging current: This situation often occurs when the protection board is not designed properly and charging is not done properly. We often like to charge the device for a while after it is fully charged, so that our device can withstand it for a longer time. However, what many people do not know is that long-term overcharging and overdischarging can seriously damage and destroy the performance of lithium batteries, and in severe cases, it can lead to extreme situations such as explosions. Therefore, it is better for the battery to be fully charged. If it is always plugged into the charger, it will eventually lead to tragedy.
3. During charging and discharging, the current of the charger and the general current load of the electrical appliance should also be within the specified range. Excessive current load can easily cause internal short circuits in the battery, thereby damaging lithium ions and causing safety hazards in the circuit. Similarly, the same principle applies to the voltage of rechargeable chargers. So we should also pay attention to whether the charger is qualified when using it.
4. Work environment. Lithium batteries are extremely sensitive to temperature, and if used below freezing point for a long time, it may have a significant impact and harm on battery life. However, long-term exposure to an overheated environment can significantly reduce the lifespan of the battery, and in severe cases, it can cause an explosion due to increased internal pressure. Even if there is no explosion, the battery will quickly be scrapped in high heat. It seems that in some cases, unfortunate deaths due to pool explosions are mostly caused by the high temperature of its working environment.
After experiencing multiple accidents, manufacturers have finally taken action by adding protective devices, especially double or multiple protections, to most electronic and digital products, in order to avoid such situations as much as possible. However, the strengthening of users' self-awareness is still very important.
The correct usage method of lithium batteries: mobile phone lithium batteries
Although lithium batteries are widely used in cars, electric vehicles, mobile phones, tablets, laptops, and other devices, there may be more devices that will use them in the near future. However, currently, devices such as mobile phones and tablets are still the closest lithium battery powered devices to us. Therefore, it is necessary to provide special instructions for the use of mobile phone lithium batteries.
How to Charge 1
When using lithium batteries, it should be noted that the battery enters a sleep state after being left for a period of time, at which point the capacity is lower than normal and the usage time is shortened accordingly. But lithium batteries are easy to activate, as long as they undergo 3-5 normal charge and discharge cycles to activate the battery and restore normal capacity. Due to the inherent characteristics of lithium batteries, they have almost no memory effect. Therefore, the new lithium battery in the user's mobile phone does not require any special methods or equipment during the activation process. Not only in theory, but also in my own practice, using standard charging methods from the beginning as a 'natural activation' approach is the best. For the issue of "activation" of lithium batteries, many opinions suggest that the charging time must exceed 12 hours and be repeated three times in order to activate the battery. The statement that 'the first three charges should be charged for more than 12 hours' is clearly a continuation of nickel batteries such as nickel cadmium and nickel hydrogen. So this statement can be said to have been a misconception from the beginning. There is a significant difference in the charging and discharging characteristics between lithium batteries and nickel batteries, and it can be clearly stated that all the serious formal technical materials I have reviewed emphasize that overcharging and overdischarging can cause huge damage to lithium batteries, especially liquid lithium-ion batteries. Therefore, it is best to charge according to standard time and methods, especially not for over 12 hours of ultra long charging. Usually, the charging method described in the phone manual is the standard charging method suitable for the phone.
In addition, lithium battery phones or chargers will automatically stop charging after the battery is fully charged, and there is no so-called "trickle" charging that lasts for more than 10 hours with nickel chargers. That is to say, if your lithium battery is fully charged and placed on a charger, it will still be charged for nothing. And none of us can guarantee that the characteristics of the battery's charge and discharge protection circuit will never change and the quality will be foolproof, so your battery will be hovering on the edge of danger for a long time. This is also another reason why we oppose long charging. In addition, on some mobile phones, if the charger is not removed after a certain period of charging time, the system will not only not stop charging, but also start a discharge charge cycle. Perhaps the manufacturers of this approach have their own purposes, but it is clearly detrimental to the lifespan of batteries and mobile phones/chargers. At the same time, long charging requires a long time and often needs to be carried out at night. Based on the situation of China's power grid, the voltage at night is relatively high and fluctuates greatly in many places. As mentioned earlier, lithium batteries are very delicate, and their ability to withstand fluctuations in charging and discharging is much worse than nickel batteries, which brings additional dangers. In addition, another aspect that cannot be ignored is that lithium batteries are also not suitable for over discharge, which is also detrimental to lithium batteries. This leads to the following question.
When should charging start during normal use
On our forum, we often see this statement, because the number of charging and discharging times is limited, so the phone battery should be used up as much as possible before recharging. But I found an experimental table about the charging and discharging cycles of lithium-ion batteries, and the data about the cycle life is listed as follows:
Cycle life (10% DOD):> 1000 times
Cycle life (100% DOD):> 200 times
DOD stands for Depth of Discharge. From the table, it can be seen that the number of rechargeable cycles is related to the depth of discharge, and the cycle life at 10% DOD is much longer than that at 100% DOD. Of course, if converted to the actual total charging capacity: 10% * 1000=100, 100% * 200=200, the latter's complete charging and discharging is still better. However, the statement made by the previous netizen needs to be corrected: under normal circumstances, you should charge the battery according to the principle of using up the remaining battery before charging. But if your battery cannot last the entire day on the second day, you should start charging in a timely manner. Of course, if you are willing to carry the charger to the office, that's another matter. And when you need to charge to cope with important events that are expected to cause busy communication, even when the battery still has a lot of remaining power, you just need to charge in advance because you haven't really lost "1" charging cycle life, which is "0. x" times, and often this x is very small. The principle of recharging after the remaining battery power is not to go to extremes. A widely circulated saying, like long charging, is "try to use up the battery of your phone as much as possible, preferably with automatic shutdown". This approach is actually only used on nickel batteries to avoid memory effects, unfortunately it has also been passed down in lithium batteries today. There was an example of someone who continued to use their phone without charging it even after receiving a warning of low battery level and continued to use it until it automatically shut down. As a result, the phone in this example did not respond during subsequent charging and startup, and had to be sent to customer service for repair. This is actually due to the low voltage caused by excessive discharge of the battery, resulting in the inability to have normal charging and startup conditions.
3 Important Tips for Proper Use of Lithium Battery Mobile Phones
In summary, my most important tip on the charging and discharging issues of lithium battery smartphones during use is:
1. Charge according to standard time and procedures, even for the first three times;
2. When there is a low battery prompt on the phone, it is advisable to start charging as soon as possible;
3. The activation of lithium batteries does not require any special method, as they will naturally activate during normal use of the phone. If you insist on using the widely circulated "first three 12 hour long charging activation" method, it will not actually be effective. Therefore, all the practices of pursuing 12 hour ultra long charging and using lithium battery phones for automatic shutdown are wrong. If you have previously followed incorrect statements, please correct them in a timely manner, perhaps it is not too late. Of course, with good self-protection and control circuit quality of mobile phones and chargers, there is still a considerable guarantee for the protection of lithium batteries. So understanding the charging rules is the key, and in some cases, some concessions can also be made. For example, if you find that your phone needs to be charged before you go to bed at night, you can also start charging it before bedtime. The key to the problem is that you should know what the correct approach is and not deliberately follow the wrong statements.
The correct usage of lithium batteries and battery maintenance:
In fact, there are not many usage considerations for batteries, in other words, they are not very useful. The difference in how many times a battery can be used is more due to individual differences in the manufacturing of the battery itself, rather than the method of use. Besides the quality of the battery itself, the lifespan of the battery itself is limited. Once the battery is taken off the production line, its lifespan begins to run out. Whether you use it or not, the lifespan of lithium batteries is only two to three years. One of the important reasons for the decrease in battery capacity is the increase in internal resistance caused by oxidation. Eventually, the resistance of the electrolytic cell will reach a certain point, and although the battery is fully charged at this time, it cannot release the stored electricity. Many friends believe that when using a lithium battery for the first time, it should be charged for more than 16 hours to fully activate the battery. However, there is no basis for this. This is just the popular charging method for nickel hydrogen or nickel cadmium batteries at that time, which is not suitable for lithium-ion batteries. Because this type of battery with lithium polymer as its core theoretically does not have a memory effect, even if it does, it can be completely ignored. So it only takes about 3 hours to fully charge. If it shows that the charging is completed and no external power supply is needed temporarily, then you can unplug the power supply without waiting for such a long time.
In fact, battery maintenance has always been a hot topic among laptop users, and in the battery section of major laptop forums, this topic has long formed a consensus. But in fact, there are many misunderstandings here, which ultimately come from two aspects. One is that "thinking has not kept up with the transition from nickel hydrogen batteries to lithium batteries". The other, even funnier, comes from mobile phones, because mobile phones are actually the first devices that most users come into contact with using repeatedly charged batteries, so they will naturally extend some habits of mobile phones to PSP. I don't have the ability to train most PSP users into experts, and there's no need for that either. There is no absolute truth in the world, and I will not, like some friends who prioritize theory over theory, confidently claim that my theory must be correct and convince everyone. I will only share with everyone the viewpoints that are widely recognized on major notebook forums and among senior engineers in the electrical industry. Ultimately, PSP is a consumable product, and no matter how hard you try, the battery life is only 2-3 years. If you feel that the so-called maintenance methods that bring minimal to almost no effect to PSP batteries willingly interrupt the game and wait for charging to complete the charging and discharging time, then you don't need to continue reading.
Below, I will clarify some of the most common misconceptions and provide what I believe are the correct perspectives and approaches.
Misconception 1: PSP requires repeated charging and discharging three times to activate the battery. Unless you have purchased a PSP that has been in stock for over a year, there is no need to do so because the battery cells are already activated when they leave the factory, and when they are packaged into PSP batteries, they undergo another equivalent activation test. Therefore, the battery you receive is already activated, and performing three more charging and discharging processes will only unnecessarily increase battery loss.
Misconception 2: The first charge must be fully charged for 12 hours. This is applicable to early nickel hydrogen battery devices without battery control circuits, but it is a joke for PSP with intelligent charge and discharge control modules today. When the PSP battery is fully charged, the charging current will be automatically cut off and displayed as "external power supply" in the system. Even if you continue charging for 120 hours, the status will not change at all. Generally speaking, it is fully charged in 3 hours, and the remaining "charging" is just a waste of your time. On the contrary, when you receive a new machine, you should first discharge the battery before charging it.
Misconception 3: Batteries need to be thoroughly charged and discharged once a month. For nickel hydrogen batteries with strong memory effects, this is a necessary task, but for lithium batteries, this cycle is too frequent. Lithium batteries theoretically eliminate memory effects, and even if they do, they have greatly reduced the negligible level. If you use batteries frequently, you should discharge the battery to a relatively low level (about 10-15%) before charging. However, if the discharge is so low that even the machine cannot be turned on (0-1%), it is a deep discharge that causes significant damage to the lithium battery. Generally, this operation should be done every two months. If you rarely use batteries, then just perform this operation once every 3 months.
Misconception 4: Working while charging or continuing to use an external power source after charging can damage the host and battery. This is the most ridiculous argument. How many reactions can be obtained in practice from theoretical arguments on mechanisms such as hole electrons and secondary charges? The academic community in the battery industry has inconsistent views on this issue. There are still differences in theory, how can it be used to guide consumers in practical use? The loss of batteries can be divided into normal loss and harmful loss. The degree of loss caused by external power supply use and charging while using is completely within the normal loss range of batteries. That is to say, no matter how systematic and theoretical maintenance measures are taken, batteries will age. This is just like how miraculous cosmetics and maintenance cannot prevent beautiful women from becoming old women, at most they can only delay. However, the true effectiveness of surface decoration cannot be explained by theory - respecting practical experience is the correct and scientific understanding. Perhaps some people say that the only way to avoid battery aging is not to use it (so many people choose to remove the battery), but this makes PSP portability meaningless. Secondly, even when the battery is in a sealed state, it naturally ages over time. Batteries are actually semi consumables, and as long as they bring you enough convenience and happiness, I think their sacrifice is valuable.
There are misconceptions, naturally due to the corresponding widely recognized views on battery maintenance and usage methods:
1. Avoid complete discharge (use until black screen power failure)
2. Regularly charging and discharging lithium batteries, charging them before they are fully discharged, using external power sources while charging, or continuing to use external connections after charging will not cause additional damage to the battery.
When not in use for a long time, the lithium battery should be removed and placed in a cool and dry place. Do not freeze to avoid moisture erosion. Avoid using in cars with high temperatures. If stored for a long time, charge the battery to 40% and place it
As a laptop user, if you spend most of your time using a fixed power source, you can remove the battery and place it in a cool place, but this is only for the purpose of improving environmental factors such as temperature and humidity. As a PSP, using an external power source with a battery installed will not cause additional damage to the battery. And based on the concept of portability and protection of battery covers and metal contacts, it is recommended not to frequently disassemble the battery due to the use of external power sources.
5. Avoid purchasing spare lithium batteries for storage, as even if the battery is not in use, its lifespan will naturally deteriorate. Therefore, maximizing the use of the battery within its limited lifespan is the embodiment of its value, rather than torturing oneself and the PSP used for entertainment with unrealistic theories.
