Aug 14, 2020 Pageview：70
Lithium ion battery is a rechargeable secondary battery, which can recover power and continuously release electric energy by charging. Compared with other rechargeable batteries, lithium-ion batteries have faster charging rate and longer cycle life. However, after long-term use, the capacity of lithium-ion batteries will gradually lose, and the time required for full charging will become. Eventually, the lithium-ion battery will completely lose its charging capacity and become a dead battery.
Why does lithium ion battery die
It has been proved by experiments that there are many reasons leading to the death of lithium-ion battery, which will lead to the loss of lithium-ion battery capacity. The main reasons for the capacitance loss of lithium-ion batteries are as follows:
The negative electrode surface of lithium ion battery is plated with lithium. During the charging process, lithium ion from the positive electrode of the battery may be adsorbed on the graphite of the negative electrode and form a solid electrolyte interface film on the surface of the negative electrode. This kind of film is called SEI film, which is mainly composed of lithium oxide and lithium carbonate. The chemical reaction is mainly active when the battery is charged at a low voltage (less than3.92V) or at a high C rate (more than 1C). As the battery continues to charge and discharge cycles, the SEI film will become thicker and thicker, which will eventually hinder the normal charge and discharge of the battery.
Electrolyte oxidation of positive electrode of lithium ion battery: The main reason for this phenomenon is that the temperature is too high or the voltage is too high (more than 4.1V). This reaction will make the battery rapidly degenerate and move towards the end of service life faster.
In order to measure the life expectancy of lithium-ion batteries, experts invented coulomb efficiency (CE). Generally speaking, the higher the CE value of the battery, the longer its cycle life. The perfect battery CE value is 1.0, and the battery with 0.9999 CE value is already very good. At present, lithium titanate battery with the best CE value can provide about 10000 cycle life, but its cost and energy ratio are not satisfactory.
However, in addition to the above two reasons, the mechanical degradation of the electrode or the loss of stack pressure in the bag battery are also the reasons for the loss of battery capacitance. This problem is usually solved by improving the design of the battery or adding electrolyte additives.
Are you killing your lithium ion battery
Unreasonable use of lithium-ion batteries will aggravate the death of batteries.The price of lithium-ion battery is generally expensive. In order to maximize the role of the battery and improve the cost performance of the battery, battery users should learn how to extend the cycle life of the battery.
First of all, you need to solve the problem of battery heating, because high temperature will aggravate the parasitic reaction of electrolyte inside lithium-ion battery, which will cause irreversible loss of battery capacity. When storing lithium-ion batteries, the batteries should be stored in a cool and dry place (5 ℃ to 25 ℃). When using lithium-ion batteries, avoid exposing the batteries to high temperatures above 60 ℃. In addition to the influence of ambient temperature, the battery itself will also release a lot of heat during charging and discharging, especially in the case of fast charging and high power output. To avoid this as much as possible, you can try charging at a lower rate (less than 1c), which can effectively extend the cycle life of the battery. Don't use so-called fast chargers, which usually claim to fully charge a lithium-ion battery within an hour. Although the fast charger does make the lithium-ion battery charge faster, using this charger will undoubtedly kill your lithium-ion battery.
Another thing you need to solve is the charge level of lithium-ion batteries. Many people are used to charging the battery to 100%, which can maximize the capacity of lithium-ion battery, but it is harmful to the cycle life of the battery. The degradation efficiency of the battery at high voltage level will be accelerated (more than 4.1V), if the battery charging capacity is controlled below 80%, the parasitic reaction of the battery will be effectively suppressed, and the battery life will be longer. If you want to idle your lithium-ion battery for a long time, controlling its power level between 30% and 60% can also protect the battery's cycle life.
Will lithium ion battery life expectancy change
Yes, of course, the cycle life of lithium-ion batteries is greatly affected by the way they are used and the environment in which they are used. The capacitance of lithium-ion battery is easy to be damaged after deep charge and discharge cycles with high intensity. If the lithium-ion battery is exposed to high temperature or overheated, its degradation effect will be very obvious.
Through reasonable use and storage methods, we can make lithium-ion batteries live as long as possible. When using the battery, it is not necessary to fully charge the battery to 100%. In this way, the battery voltage will not be too high and the parasitic reaction will be reduced. In the same way, we should pay attention to the temperature of the working environment of the battery when using and storing the battery, and choose the battery with lower C rate. These methods can reduce the heating of the battery as much as possible. In addition, when storing the battery, it is necessary to reserve some power for the battery to maintain its voltage not too low. In the long-term storage, it is necessary to charge part of the lithium-ion battery for at least three months to prevent the loss of electricity.
Everyone hopes that the life expectancy of their lithium-ion batteries will be longer. After all, the price of lithium-ion batteries is relatively high, and no one is willing to replace them with new lithium-ion batteries frequently because of battery degradation. Therefore, it is necessary for users to understand how lithium batteries degrade and how to minimize the impact of degradation effects. Hope you can find this article helpful.
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