How long is the life cycle of lithium ternary battery?
- Dec 06, 2018 -
As the range of new energy vehicles is limited, how to improve the range affects the whole market. In the battery industry, ternary lithium battery with many advantages quickly occupied 3C, automobile and other markets, and gradually replaced the traditional lead-acid battery. For traditional batteries, ternary lithium battery has the advantages of long life, energy saving, environmental protection, pollution free, low maintenance cost, complete charge and discharge, light weight and so on. In some publicity materials, some people think that ternary lithium battery life is long, is it really so? How many cycles does it go through? Let's uncover the truth.
In nature, lithium is the lightest metal with the smallest atomic mass. Due to its active chemical properties, lithium is easy to lose electrons and be oxidized to Li+. The standard electrode potential is -3.045v and the electrochemical equivalent is 0.26g/Ah. The ternary lithium battery refers to the lithium secondary battery which USES nickel-cobalt-manganese three transition metal oxides as positive electrode materials. It fully integrated the nickel cobalt acid lithium good cycle performance, high capacity of acid lithium and lithium manganese acid of high security and low cost etc., using molecular hybrid, doping, coating and surface modification methods such as synthesis of nickel cobalt manganese compound lithium oxide, multielement synergy is currently widely research and application of a lithium ion rechargeable battery.Ternary lithium battery life is in use to a certain extent, the ratio of capacity attenuation degree calculated, directly to the capacity life is zero to terminate.Industry algorithms are generally three lithium battery charge after discharge once, this is called cycle life.In the process of use, irreversible chemical reactions inside the lithium battery will cause the battery capacity to decline, such as improper use, or very high temperature or very low temperature when used.For example, the decomposition of electrolyte, the inactivation of active material, and the collapse of positive and negative pole structure lead to the reduction of the number of lithium ions embedded and unembedded, etc.Experiments show that higher discharge rate will lead to faster capacity attenuation, if the discharge current is low, the battery voltage will be close to the balance voltage, can release more energy.
Theory of ternary lithium battery life expectancy of 1200 fully charge and discharge, which is completely cycle life, according to the use frequency, once three days fully charge and discharge, fully charge and discharge of 120 times a year, the ternary lithium battery service life to 10 years, even if in use process loss or the number of days to charge and discharge reduction, also can achieve eight years, note that said here is that the capacity of life, after eight years of ternary lithium battery capacity will be more than sixty percent, that is standard.
The theoretical life of ternary lithium battery is medium in commercial rechargeable lithium battery.Lithium iron phosphate is about 2,000 cycles, while lithium titanate is said to have 10,000 cycles.At present, mainstream battery manufacturers promise more than 500 times in the ternary cell specification (charging and discharging under standard conditions). However, after the battery is assembled and made into a battery pack, due to the consistency problem, the voltage and internal resistance cannot be exactly the same, and the cycle life is about 400 times.The manufacturer recommends that the SOC operating window is 10%~90%, and it is not recommended to conduct deep charging and discharging, otherwise it will cause irreversible damage to the positive and negative pole structure of the battery. If the calculation is based on shallow charging and discharging, the cycle life will be at least 1000 times.In addition, lithium battery life can be significantly reduced to less than 200 times if it is often discharged at high magnification and high temperature.