Lithium battery’, is a class of lithium metal or lithium alloy for the anode material, the use of non-aqueous electrolyte solution of the battery. 1912 lithium metal batteries were first proposed by Gilbert N. Lewis and research. 1970s, M.S. Whittingham proposed and began to study the lithium-ion battery. Due to the chemical properties of lithium metal is very active, making the processing, preservation and use of lithium metal, the environmental requirements are very high. Therefore, lithium batteries have not been applied for a long time. With the development of science and technology, lithium batteries have now become mainstream.
Lithium batteries can be broadly divided into two categories: lithium metal batteries and lithium ion batteries. Lithium-ion batteries do not contain lithium in metallic form and are rechargeable. The fifth generation of rechargeable batteries, lithium metal batteries, was born in 1996, which is better than lithium ion batteries in terms of safety, specific capacity, self-discharge rate and performance-price ratio. Due to the limitation of its own high technical requirements, only a few companies in a few countries are now producing these lithium metal batteries.
Battery life
Lithium-ion batteries can only be charged and discharged 500 times?
I believe that the vast majority of consumers have heard that the life of lithium batteries is ‘500 times’, 500 times charging and discharging, more than this number of times, the battery ‘end of life’, many friends in order to prolong the life of the battery, each time in the battery is completely exhausted Charge only when the battery is completely depleted, so the life of the battery really have to extend the role? The answer is no. Lithium battery life is ‘500 times’, not the number of times of charging, but a cycle of charging and discharging.
A charge cycle means the process of using all of the battery's charge from full to empty and then from empty to full, which is not the same as charging it once. For example, a lithium-ion battery is only half-used on the first day, and then it is fully charged again. If it is still so on the second day, i.e., it is charged when half used, for a total of two charges down the line, this can only be counted as one charging cycle, not two. Therefore, it can often take several charges to complete a cycle. For each completed charging cycle, the battery capacity is reduced a little. However, this reduction in capacity is so small that high quality batteries will still retain 80% of their original capacity after many cycles of charging, and many lithium-powered products are still in use as usual after two or three years. Of course, lithium batteries still need to be replaced when they reach the end of their life.
And the so-called 500 times, means that the manufacturer in a constant depth of discharge (such as 80%) to achieve about 625 times the number of chargeable times, reaching 500 charging cycles.
(80% * 625 = 500) (ignoring factors such as the reduction of lithium battery capacity)
But due to the various influences of real life, especially the depth of discharge during charging is not constant, so ‘500 charging cycles’ can only be used as a reference battery life.
Correct statement: Lithium battery life is related to the number of completed charging cycles, and not directly related to the number of times of charging.
Simple understanding, for example, a lithium battery in the first day only used half of the charge, and then fully charged for it. If it does the same on the second day, i.e., it is charged when it is half-used, for a total of two charging down, this can only be counted as one charging cycle, not two. Therefore, it can often take several charges to complete a cycle. With each completed charging cycle, the charge level is reduced a little. However, the reduction is so small that a high quality battery will still retain 80% of its original charge after several cycles, and many lithium-powered products continue to work as usual after two or three years for this reason. Of course, lithium battery life to the eventual need to be replaced.
The life of lithium batteries is generally 300 to 500 charging cycles. Assuming that a complete discharge to provide power for Q, such as not considering the reduction of power after each charging cycle, the lithium-ion battery in its life can provide a total of 300Q-500Q of power or for its replenishment. From this we know that if it is charged every time it is used 1/2, it can be charged 600-1000 times; if it is charged every time it is used 1/3, it can be charged 900-1500 times. And so on, if you charge randomly, the number of times is variable. In short, no matter how to charge, the total replenishment of 300Q to 500Q of power is constant. Therefore, we can also understand this way: lithium battery life is related to the total charge power of the battery, and has nothing to do with the number of times of charging. The difference between deep discharge and shallow discharge is not significant for Li-ion battery life.
In fact, shallow charging is more beneficial to Li-ion, only when the power module of the product is calibrated for Li-ion, there is a need for deep charging. Therefore, the use of lithium-powered products do not have to stick to the process, everything to the convenience first, charge at any time, do not have to worry about the impact of life.
If lithium-ion batteries are used at temperatures higher than the specified operating temperature, i.e. above 35°C, the battery charge will continue to diminish, i.e. the battery will not be powered for as long as usual. If the device has to be charged at such temperatures, the damage to the battery will be even greater. Even storing batteries in a hotter environment will inevitably damage the quality of the battery accordingly. Therefore, trying to keep at a moderate operating temperature is a good way to extend the life of lithium batteries.
If the lithium-ion battery is used in a low-temperature environment, i.e., below 4°C, you will also find that the battery's usage time is reduced, and the original lithium-ion batteries of some mobile phones can't even be charged in a low-temperature environment. However, there is no need to worry too much, this is only a temporary situation, unlike the use of high-temperature environment, once the temperature rises, the molecules in the battery is heated, it will be immediately restored to the previous charge.
To get the most out of a lithium-ion battery, you need to use it often so that the electrons within the lithium battery are always in a state of flow. If you don't use lithium batteries often, please remember to complete a charging cycle for lithium batteries once a month to do a power calibration, i.e., deep discharge and deep charge once.
Formal call is ‘charge and discharge cycle’, not equal to the ‘number of charge’, the cycle refers to, the battery from fully charged to exhausted, which is a cycle, if your battery from the fully charged state, with one-tenth of the power, and then full, which is one-tenth of a cycle, so charging 10 times, and then full, this is a cycle. cycle, so charge it 10 times before it's basically a cycle. Similarly, if you go from full charge, use it half way and then full, then use it half way and then full again, that's a cycle, at which point you are charging it twice. So, the cycle just depends on ‘how much electricity is discharged from the battery’, and is not directly related to ‘how many times it is charged’.
And the nominal number of charge/discharge cycles is not to say that it can't be used after using it, but after doing so many cycles, the battery's ability to store power will be reduced to a degree, for example, a lithium battery's nominal charge/discharge cycle is ‘not less than 60% of the nominal capacity after 500 cycles’.
For example, a lithium battery, the nominal charge/discharge cycle is ‘not less than 60% of the nominal capacity after 500 cycles’.
That is, after 500 cycles, the battery can only store up to 60% of the time of the new battery so much electricity, is the performance declined to a certain extent, is the meaning of this
Lithium batteries do not have a fixed limit on the number of charges, regular manufacturers out of the battery can generally at least charge and discharge 500 times, and the capacity to remain in the initial capacity of more than 80%, a day a charge can be used for 2 years. Usually mobile phone battery charging 1000 times, it will cause the battery is seriously not durable.
Mobile phone battery maintenance methods:
1, each time completely fully charged to use, reduce the number of times to charge, improve battery life.
2, do not need to discharge the battery completely, usually less than 10% of the power needs to be charged.
3, use the original charger to charge, don't use universal charger to charge.
4, mobile phone charging process, do not use mobile phones.
5、Don't overcharge, stop continuing to charge after the battery is full.
Yes, according to experimental results, the life of lithium batteries is with the number of times with the increase in the number of charging and continuous attenuation, the general lithium battery charging times is 2000-3000 times
Cycle is to use, we are using the battery, concerned about the use of time, in order to measure the rechargeable battery in the end can be used for how long such a performance, the definition of the number of cycles. The actual user use varies greatly, because the conditions of different tests are not comparable, to have a comparison must be standardised cycle life definition.
National standard lithium battery cycle life test conditions and requirements: in the ambient temperature of 20 ℃ ± 5 ℃ conditions, 1C charging, when the battery terminal voltage reaches the charging limit voltage 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 to the termination voltage of 2.75V at a current of 1C, the end of discharge, set aside for 0.5h ~ 1h, then the next charge and discharge cycle, until two consecutive discharge time is less than 36min, it is considered that the life of the cycle is terminated. 0.5h~1h, and then carry out the next charging and discharging cycle until the time of two consecutive discharges is less than 36min, then the life is considered to be terminated, and the number of cycles must be more than 300 times.
Interpretation of the national standard regulations.
A. This definition specifies that the cycle life test is carried out by deep charging and deep discharging.
B. It stipulates that the cycle life of Li-ion battery is in accordance with this mode, and the capacity is still more than 60% after ≥300 cycles.
However, the cycle times obtained by different cycle systems are very different. For example, if the other conditions above remain unchanged, and the constant voltage of 4.2V is changed to 4.1V for the same type of battery to carry out the cycle life test, so that the battery is no longer deep-charged, and the cycle life times obtained from the final test can be increased by nearly 60%. Then if the cut-off voltage is increased to 3.9V for testing, the number of cycles should be increased several times.
This about the cycle of charging and discharging once less than the life of a statement, we have to pay attention to is the definition of lithium battery charging cycle: a charging cycle refers to all the lithium battery charge from full to empty, and then by the process of charging empty to full. And this is not the same as charging once. In addition we can't ignore the conditions of the cycle when talking about the number of cycles, it doesn't make any sense to talk about the number of cycles leaving aside the rules, because the number of cycles is a means of detecting the life of the battery, not an end in itself!