Lithium ion battery can only charge and discharge 500 times?
"Lithium battery" is a kind of battery with lithium metal or lithium alloy as anode material and non-aqueous electrolyte solution. In 1912, lithium metal batteries were first developed by GilbertN.Lewis Put forward and study. In the 1970s, M.S. Whittingham proposed and began to study lithium-ion batteries. Because the chemical properties of lithium metal are very active, the processing, storage and use of lithium metal have very high environmental requirements. Therefore, lithium batteries have not been used for a long time. With the development of science and technology, lithium batteries have become the mainstream.
Lithium batteries can be roughly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium ion batteries do not contain metallic lithium and are rechargeable. Lithium metal battery, the fifth generation product of rechargeable battery, was born in 1996. Its safety, specific capacity, self discharge rate and performance price ratio are better than lithium ion battery. Due to its own high-tech requirements, only a few countries are producing this kind of lithium metal battery.
Lithium ion battery can only charge and discharge 500 times?
I believe the vast majority of consumers have heard that the life of lithium batteries is "500 times". After 500 times of charging and discharging, the battery will "die". In order to prolong the life of the battery, many friends charge the battery when the battery is completely exhausted. Does this really prolong the life of the battery? The answer is No. The life of lithium battery is "500 times", which refers to a cycle of charge and discharge rather than the number of charges.
A charging cycle means that all the power of the battery is from full to empty, and then from empty to full, which is not the same as charging once. For example, a lithium battery only uses half of its capacity on the first day, and then it is fully charged. If this is still the case the next day, that is, charging half of the battery and charging twice in total, it can only be counted as one charging cycle, not two. Therefore, it may take several times to complete a cycle. The battery capacity will be reduced a little after each charging cycle. However, this power reduction is very small. High quality batteries will still retain 80% of their original capacity after charging for many cycles. Many lithium battery power supply products will still be used as usual after two or three years. Of course, the lithium battery still needs to be replaced when it reaches the end of its life.
The so-called 500 times means that the manufacturer has achieved about 625 chargeable times at a constant discharge depth (such as 80%), reaching 500 charging cycles.
(80% * 625 = 500)
However, due to various influences of real life, especially the discharge depth during charging is not constant, so "500 charging cycles" can only be used as a reference for battery life.
Correct statement: lithium battery life is related to the completion times of charging cycle, but not directly related to the charging times.
A simple understanding, for example, is that a piece of lithium battery only uses half of its capacity on the first day, and then it is fully charged. If this is still the case the next day, that is, charging half of the battery and charging twice in total, it can only be counted as one charging cycle, not two. Therefore, it may take several times to complete a cycle. Every charging cycle is completed, the power will be reduced a little. However, the reduction is very small. High quality batteries will still retain 80% of the original power after charging for many cycles. This is why many lithium battery power supply products are still in normal use after two or three years. Of course, lithium battery life to the end or need to be replaced.
The life of lithium battery is generally 300-500 charging cycles. Assuming that the amount of electricity provided by a complete discharge is Q, if the decrease of the amount of electricity after each charging cycle is not considered, the lithium battery can provide or supplement 300q-500q of electricity in its lifetime. From this, we know that if you charge with 1 / 2 each time, you can charge 600-1000 times; if you charge with 1 / 3 each time, you can charge 900-1500 times. And so on, if the charge is random, the number of times is variable. In a word, no matter how to charge, a total of 300q ~ 500q power will be added, which is constant. Therefore, we can also understand this way: the life of lithium battery is related to the total charge of the battery, and has nothing to do with the charging times. There is little difference between deep discharge and deep charge and shallow discharge and shallow charge on the life of lithium battery.
In fact, shallow discharge and shallow charging are more beneficial to lithium battery. Only when the power module of the product is calibrated for lithium battery, it is necessary to conduct deep discharge and deep charging. Therefore, the use of lithium power supply products do not have to adhere to the process, all convenience first, charging at any time, do not have to worry about the impact of life.
If the lithium battery is used in an environment higher than the specified operating temperature, that is, 35 ° C or above, the battery power will continue to decrease, that is, the battery power supply time will not be as long as usual. If you charge the device at this temperature, the damage to the battery will be greater. Even if the battery is stored in a hot environment, it will inevitably cause corresponding damage to the quality of the battery. Therefore, it is a good way to prolong the life of lithium battery to keep the operating temperature as suitable as possible.
If lithium batteries are used in low temperature environment, i.e. below 4 ° C, the service time of batteries will also be reduced. Some original lithium batteries of mobile phones can't even be charged in low temperature environment. But don't worry too much. This is just a temporary situation. Unlike the use in high temperature environment, once the temperature rises, the molecules in the battery will be heated, and the power will immediately return to the previous level.
In order to maximize the efficiency of lithium-ion battery, it is necessary to use it frequently, so that the electrons in the lithium-ion battery are always in a flowing state. If you don't use lithium battery frequently, please remember to complete a charging cycle for lithium battery every month, and do a power calibration, that is, deep discharge and deep charge.
The normal name is "charge discharge cycle", which is not equal to "charging times". Cycle refers to the cycle from full charge to full use of the battery. If your battery is from full charge, it uses one tenth of the amount of electricity, and then it is full again, which is one tenth of a cycle. This kind of charging 10 times is basically a cycle. Similarly, from full charge, half charge and then full charge, and then half charge and then full charge, this is also a cycle. At this time, you charge twice. Therefore, the cycle only depends on "how much electricity is discharged from the battery", and has no direct relationship with "charging times".
Moreover, the nominal number of charging and discharging cycles does not mean that the battery can not be used up, but after so many cycles, the battery's ability to store electricity will be reduced to a certain extent,
For example, the nominal charge discharge cycle of a lithium battery is "no less than 60% of the nominal capacity after 500 cycles"
That is to say, after 500 cycles, the battery can only store 60% of the power of the new battery at most, which means that the performance has dropped to a certain extent
There is no fixed limit for charging times of lithium batteries. The batteries from regular manufacturers can charge and discharge at least 500 times, and the capacity is maintained at more than 80% of the initial capacity. One charge a day can last for two years. Usually, if the mobile phone battery is charged 1000 times, it will cause the battery to be seriously not durable.
Mobile phone battery maintenance method:
1. Every time fully charged use, reduce charging times, improve battery life.
2. You don't need to discharge the battery completely. You usually need to charge when the charge is less than 10%.
3. Use the original charger, do not use universal charger.
4. Do not use the mobile phone during charging.
5. Don't overcharge. Stop charging after the battery is full.
Yes, according to the experimental results, the life of lithium battery is declining with the increase of charging times. Generally, the charging times of lithium battery is 2000-3000 times
Cycling is use. We are using the battery. What we care about is the time of use. In order to measure the performance of how long the rechargeable battery can be used, we define the number of cycles. The actual use of the user is ever-changing, because there is no comparability between different conditions of the test, to have a comparison, we must standardize the definition of cycle life.
The cycle life test conditions and requirements of lithium battery stipulated in the national standard: charge at 1C under the ambient temperature of 20 ℃± 5 ℃. When the terminal voltage of the battery reaches the charging limit voltage of 4.2V, change to constant voltage charging until the charging current is less than or equal to 1 / 20c, stop charging, set aside for 0.5h ~ 1H, and then discharge at 1C until the terminal voltage is 2.75V. After the discharge, set aside for 0.5h ~ 1H, and then conduct the test In the next charge discharge cycle, until the time of two consecutive discharges is less than 36 min, the life is considered to be terminated, and the number of cycles must be more than 300.
Interpretation of national standard provisions:
A. This definition stipulates that the cycle life test is conducted by deep charging and deep discharging
B. The cycle life of lithium battery is defined. According to this mode, after more than 300 cycles, the capacity is still more than 60%
However, the number of cycles obtained by different cycle systems is quite different. For example, if the above other conditions remain unchanged, only the constant voltage of 4.2V is changed to the constant voltage of 4.1V to test the cycle life of the same type of battery. In this way, the battery is no longer the deep charging mode. Finally, the cycle life of the battery can be increased by nearly 60%. If the cut-off voltage is increased to 3.9v, the number of cycles should be increased several times.
As for the statement that one cycle of charge and discharge will lead to one less lifetime, we should pay attention to the definition of the charging cycle of lithium battery: a charging cycle refers to the process of all the charge of lithium battery from full to empty, and then from empty to full. And that's not the same as charging once. In addition, when we talk about the number of cycles, we can't ignore the conditions of the cycle. It's meaningless to talk about the number of cycles without putting aside the rules, because the number of cycles is a means of testing battery life, not an end!