How many years can lithium batteries generally last? What is the lifespan of lithium batteries?
Lithium batteries "are a type of battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. The lithium metal battery was first proposed and studied by Gilbert N. Lewis in 1912. In the 1970s, M.S. Whittingham proposed and began researching lithium-ion batteries. Due to the highly reactive chemical properties of lithium metal, its processing, storage, and use require very high environmental standards. So, 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 roughly divided into two categories: lithium metal batteries and lithium-ion batteries. Lithium ion batteries do not contain metallic lithium and are rechargeable. The fifth generation product of rechargeable batteries, lithium metal batteries, was born in 1996. Its safety, specific capacity, self discharge rate, and cost-effectiveness are all superior to lithium-ion batteries. Due to its own high-tech requirements, only a few companies from countries are currently producing this type of lithium metal battery.
BATTERY LIFE
Can lithium-ion batteries only be charged and discharged 500 times?
I believe the vast majority of consumers have heard that the lifespan of lithium batteries is "500 times". After 500 charge and discharge cycles, the battery will "end its life". Many friends, in order to extend the lifespan of the battery, only charge it when the battery is completely depleted. Does this really have an effect on extending the lifespan of the battery? The answer is negative. The lifespan of a lithium battery is "500 times", which refers not to the number of times it is charged, but to one cycle of charging and discharging.
A charging cycle means the process of the battery's entire charge from full to empty, and then from empty to full, which is not equivalent to charging once. For example, a lithium battery only uses half of its capacity on the first day and then fully charges it. If it continues like this the next day, charging half of it and charging twice in total, this can only be considered as one charging cycle, not two. Therefore, it may usually take several charges to complete a cycle. After completing each charging cycle, the battery capacity will decrease slightly. However, the decrease in battery capacity is very small. High quality batteries can still retain 80% of their original capacity after multiple cycles of charging, and many lithium powered products can still be used as usual after two to three years. Of course, lithium batteries still need to be replaced at the end of their lifespan.
And the so-called 500 times refers to the manufacturer achieving about 625 rechargeable times at a constant discharge depth (such as 80%), reaching 500 charging cycles.
(80% * 625=500) (Ignoring factors such as reduced lithium battery capacity)
However, due to various influences in real life, especially the non constant discharge depth during charging, the "500 charging cycles" can only be used as a reference for battery life.
The correct statement is that the lifespan of lithium batteries is related to the number of charging cycles completed, not directly related to the number of charging cycles.
Simply put, for example, a lithium battery only uses half of its capacity on the first day and then fully charges it. If it continues like this the next day, charging half of it and charging twice in total, this can only be considered as one charging cycle, not two. Therefore, it may usually take several charges to complete a cycle. After completing each charging cycle, the battery level will decrease slightly. However, the reduction is very small. High quality batteries can still retain 80% of their original charge after multiple cycles of charging. Many lithium powered products continue to be used as usual after two to three years, which is why. Of course, lithium batteries still need to be replaced at the end of their lifespan.
The lifespan of lithium batteries is generally 300-500 charging cycles. Assuming that the amount of electricity provided by a complete discharge is Q, without considering the decrease in electricity after each charging cycle, lithium batteries can provide or supplement a total of 300Q-500Q of electricity during their lifespan. From this, we know that if we charge with 1/2 each time, we can charge 600-1000 times; If it is charged every 1/3, it can be charged 900 to 1500 times. Similarly, if charged randomly, the number of times is not fixed. In short, no matter how it is charged, the total amount of electricity replenished is between 300Q and 500Q, which is constant. So, we can also understand it this way: the lifespan of lithium batteries is related to the total charging capacity of the battery, and not to the number of charging times. The impact of deep discharge and shallow charge on the lifespan of lithium batteries is not significantly different.
In fact, shallow discharge and shallow charge are more beneficial for lithium batteries, and deep discharge and deep charge are only necessary when the power module of the product is calibrated for lithium batteries. So, products powered by lithium batteries do not have to be limited by the process, everything is convenient first, can be charged at any time, and there is no need to worry about affecting their lifespan.
If lithium batteries are used in environments above the specified operating temperature of 35 ° C, the battery's charge will continuously decrease, meaning that the battery's power supply time will not be as long as usual. If the device needs to be charged at such a temperature, the damage to the battery will be even greater. Even storing batteries in hot environments will inevitably cause corresponding damage to the quality of the batteries. So, maintaining a suitable operating temperature as much as possible is a good way to extend the lifespan of lithium batteries.
If lithium batteries are used in low temperature environments, i.e. below 4 ° C, it will also be found that the battery life is reduced, and some phones' original lithium batteries cannot even be charged in low temperature environments. But don't worry too much, this is just a temporary situation. Unlike use in high-temperature environments, once the temperature rises, the molecules in the battery are heated and immediately restore their previous charge.
To maximize the efficiency of lithium-ion batteries, it is necessary to use them frequently to keep the electrons inside the battery in a flowing state. If you don't use lithium batteries frequently, please remember to complete a charging cycle and perform a power calibration once a month, that is, deep discharge and deep charge once.
The formal term is "charge discharge cycle", which does not equal "number of charges". A cycle refers to the process of a battery running from full charge to depletion, which is one cycle. If your battery uses one tenth of its capacity from full charge and then fully charges again, it is one tenth of a cycle. Charging it 10 times in this way is basically considered one cycle. Similarly, starting from fully charged, using half and then fully charged, and then using half and then fully charged again, this is also a cycle, at which point you have charged twice. So, the cycle only depends on how much electricity is accumulated from the battery, and is not directly related to the number of charging times.
