Battery Recycling: How to hold a perfect "funeral" of lithium battery?
Why should we recycle power lithium batteries?
Two main factors promote the development of the power battery recycling industry: the need for environmental protection and the economics of precious metal recycling.
As we all know, used batteries are a highly polluting waste. Especially for the massive size of power batteries, they contain a lot of heavy metals, electrolytes, solvents, and all kinds of organic excipients, which combine a variety of highly toxic pollutants.
Therefore, simple landfills or incineration are not suitable for the treatment of retired power batteries - and this is also a waste of resources.
First of all, "retired" power batteries do not mean they are on the verge of death. When the capacity of Li-power batteries decays to about 80% ~ 70% of their rated capacity, they are no longer suitable for electric vehicles; however, they can still meet the needs of many devices in the 80% ~ 20% range power battery performance. Only when the capacity drops to 20% is it mandatory to dispose of the battery, also known as the energy value of the battery re-mining.
The power lithium batteries also have material regeneration values besides energy values. The cobalt metal used in ternary lithium batteries is a scarce metal element distributed in the backward productivity of Africa has a high price. So many car companies choose to use 811 NCM ternary batteries (Nickel, cobalt, and manganese have a ratio of 8:1:1), cobalt-free batteries (such as Tesla), or just lithium iron phosphate batteries.
With more and more car companies announcing the complete abandonment of traditional internal combustion engine vehicles in favor of electric vehicles, as well as meeting carbon emission targets by 2050 or banning conventional internal combustion engine vehicles, this has also led to otherwise non-rare metals such as lithium or nickel metal maintaining a high price level.
Two reuse routes
The two more common words to describe the direction of power battery reuse are "disassembly and recycling" and "secondary use." Although the two are far apart, they are typically complementary rather than mutually exclusive for the power battery recycling industry.
In February 2017, "new energy vehicle power battery recycling management interim Measures" mentioned in the encouragement of battery production enterprises and comprehensive utilization enterprises, under the premise of ensuring safety and control, the waste power battery multi-level, multi-purpose rational utilization, and follow the principle of first use after recycling.
Therefore, the most ideal power battery recycling industry is to find other application scenarios for the retired power battery to continue service and then dismantle and recover the valuable metal elements after it is entirely unusable.
However, due to various influences, the current dismantling and recycling route is far more mature than the gradual utilization route, and the reality is that retired batteries are often directly scrapped without any reuse.
Dismantling and recycling
At this stage, there are two mainstream treatment processes for dismantling and recycling: pyro-recycling and wet recycling.
Pyro-recovery, also known as incineration or dry metallurgy, is to remove the organic binder in the electrode material by high-temperature incineration while causing the metal and its compounds in it to undergo redox reaction and recover the low boiling point metal and its compounds in the form of condensation and adopt sieving, pyrolysis, magnetic separation or chemical methods to recover the metal in the slag.
The advantages of this process are the wide range of raw materials that can be processed, the large processing capacity, the simplicity of the process, and the fact that the cells do not require pretreatment. However, pyro-recovery is ultimately a relatively rudimentary recovery process, with problems such as high energy consumption, low metal recovery rate, high equipment requirements, the need for further refining of recovered metals, and the generation of toxic and harmful gases. In particular, because lithium and aluminum remain in the smelting slag during the fire recovery process, further extraction and recovery is not economical, which leads to the fire route often can not recover lithium, resulting in a waste of resources, such defects become particularly prominent in today's lithium prices are at a high level.
Stepped utilization
Used battery ladder utilization refers to the process of power batteries reaching their design life and enabling them to continue to be used in a suitable working position through methods such as repair, modification, or remanufacturing. We can successively use the retired power batteries in low-power electric vehicles, power grid energy storage, and home energy storage after relevant detection and determination of their performance. When the battery performance deteriorates further, it is below the minimum utilization standard and then recycled.
If we move our eyes to the two most mainstream technology routes of power lithium batteries, we can also find differences in their respective suitable recycling routes. In short, ternary lithium batteries are ideal for disassembly and recycling, while lithium iron phosphate batteries are ideal for echelon utilization. Because from the economic point of view, the ternary materials in the metal (nickel lithium cobalt) recovery value is high, while lithium iron phosphate due to some problems with the recovery of lithium elements, the economy is relatively poor. It makes ternary batteries have a significant advantage in the selling price of recycled products, bringing a sufficient profit margin to enterprises.
LiFePO4 battery is suitable for secondary use, in addition to its poor economics of recycling materials at this stage, but also because its cycle life does have advantages. In terms of the most common energy storage for secondary use, the importance of battery performance is not high, but rather more critical cost performance.
Although the acquisition price of retired ternary batteries is higher than lithium iron phosphate, but this is mainly because of the value of metal recycling, the difference between the two cycle life, energy density is not enough to cover the additional expenditure, and the safety of ternary batteries is not as safe as lithium iron phosphate, the gradient utilization of which has additional requirements. Under multiple factors, it is decided that lithium iron phosphate is more suitable for secondary use rather than direct disassembly.
