Life cycles of Lithium-ion Battery

How many life cycles does the lithium-ion battery have?

When customer buy lithium-ion battery, the first question is what it the life cycles of the battery.It is similar with smart phone,the usage time is getting shorter when we use it one year. In the battery industry, Li(NiCoMn)O2, having many advantages of the rapid occupation of the market. It will gradually replace the conventional lead-acid batteries,especially in traffic,laptop,Solar energy storage field

Compare to the conventional battery, Li(NiCoMn)O2 have a long life, in addition to energy efficiency, eco-friendliness, low maintenance costs, full charging and discharging, light weight and numbers of other benefits. Briefly speaking, how many lifecycles a does a Li(NiCoMn)O2 battery have?

 What is Li(NiCoMn)O2?

Naturally, li ion is a light metal with a small atomic mass*, together with the atomic weight of 6.94 g/mol, ρ = 0.53 g/cm3. Li ion is chemically active as well as convenient to lose electrons to be oxidized to Li+. Accordingly, the standard electrode potential is *negative, -3.045V, and the electro chemical equivalent * is small, 0.26g/Ah. These characteristics of lithium figure it out that it is a kind of quite a high-energy material. The ternary lithium battery refers to a lithium secondary battery that makes use of three types of transition metal oxides of nickel, cobalt and manganese as a positive electrode material. It fully integrates the good cycle performance of lithium cobaltate, in addition to the high specific capacity of lithium nickelate, and the high safety and low cost of lithium manganate. It synthesizes nickel with the help of the molecular level mixing, doping, coating and surface modification. A multi-element synergistic composite lithium intercalation oxide, for instance, cobalt manganese, is a lithium ion rechargeable battery having been extensively investigated and applied.

Li(NiCoMn)O2 battery capacity and cycle life

The li(NiCoMn)O2 lifecycle implies that, following the use of the battery for a period of time, the capacity is attenuated to 70% of the nominal capacity (room temperature 25 ° C, standard atmospheric pressure, and battery capacity discharged at 0.2 C); besides that, the end of life can be considered as well. In the industry, the lifecycle is generally calculated by the number of cycles in which the lithium battery is fully charged and discharged. All through the mechanism of use, irreversible electrochemical reactions take place inside the lithium battery, which result into a decline in the capacity, for instance, decomposition of the electrolyte, deactivation of the active material, collapse of the positive and negative structures, and reduction in the number of lithium ion insertion and deintercalation. Moreover, experiments have shed light on the fact that higher rate of discharges lead to faster attenuation of the capacity. If the discharge current is lower, the battery voltage is expected to reach the equilibrium voltage, together with releasing more energy.

The theoretical life of a Li(NiCoMn)O2 is approximately 800-1000 cycles, which is medium in the commercial rechargeable lithium batteries. Lithium iron phosphate is approximately 2000 times, and lithium titanate is suggested reaching 10,000 cycles. Currently, the cell manufacturers promise more than 500 times in the Li(NiCoMn)O2 specifications produced by them (charge and discharge under standard conditions). Nevertheless, following the assembly of the batteries into the battery packs, owing to the consistency issues, voltage and internal resistance primarily cannot be exactly same, and its cycle life is approximately 400 times. The battery pack manufacturer recommends the SOC as 10%~90%. It is not recommended to carry out deep charge and discharge. Or else, it is expected to cause irreversible damage to the positive and negative structures of the battery. In case of its calculation by shallow charge and shallow release, the lifecycle is at least 1000 times. Together with that, if the lithium battery is usually discharged at a high rate and high temperature environment, the battery life will be greatly lowered to less than 200 times.

Life cycles of lithium battery are based on both the battery quality and material.

  1. The number of Li(NiCoMn)O2 is approximately 800 cycles.
  2. The number of cycles of lithium iron phosphate battery is approximately 2,500 times.
  3. The number of genuine battery and defective battery cycle is different; the original battery is designed and produced in accordance with the number of cycles on the battery manufacturer’s specification book, and the number of defective battery cycles are not likely to be 50 times.

Li(NiCoMn)O2 performance

1,The material with comparatively more balanced capacity and safety manifests better cycle performance in comparison with the normal lithium cobaltate. Its nominal voltage is merely 3.5-3.6V in the early stage owing to technical reasons. Nevertheless, there are restrictions on the scope of use, but until now, with the formulation with the continuous improvement as well as perfect structure, the nominal voltage of the battery has reached 3.7V, and the capacity has reached or exceeded the level of lithium cobalt oxide battery.

2, high energy density

3, high tap density

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