The urgency of power battery recycling and current mature technology

In 2018, China's new energy vehicle production will exceed 1 million, and in 2020 it will exceed 2 million, with a stock of more than 5 million. 2015 is the first year of China's promotion and application of new energy. In 2018, the large-scale retiring of power batteries will start soon, and it will enter an outbreak in 2019.

This article introduces three aspects of knowledge: first, the seriousness of the power battery to environmental pollution; second, the economics of power battery recycling; third, the main technology of power battery recycling, and recommendations for the recycling of power batteries.

First, the seriousness of the power battery to environmental pollution

After large-scale decommissioning of lithium-ion power batteries, as a waste, it must have adverse effects on the environment and bring about certain environmental pollution. Although lithium-ion power batteries do not contain heavy metals such as mercury, cadmium, lead, etc., and are relatively environmentally friendly compared to lead-acid batteries, metal ions of lithium-ion power batteries, carbon dust of negative electrodes, Strong alkalis and heavy metal ions in the electrolyte can cause heavy environmental pollution, including increasing the pH of the soil. Metals and electrolytes in lithium-lithium sub-cells, such as cobalt, may cause symptoms such as intestinal disorders, deafness, and myocardial ischemia. At present, China's battery recycling capacity is limited, and most of the used batteries are not effectively disposed. At present, the main disposal methods of used batteries are solidification and deep burial, and storage in waste mines. If the scale is too large, it will give the natural environment. And potential threats to human health.

In a word, if lithium-ion power batteries are retired on a large scale, people must pay great attention to them and must take them seriously and handle them safely.

Second, the energy consumption of non-ferrous metal recovery and primary metal refining process is much smaller

According to the data, the average content of lithium in the ternary battery is 1.9%, nickel 12.1%, cobalt 2.3%; in addition, copper, aluminum and other proportions also reached 13.3% and 12.7%. Cobalt has good ductility and ferromagnetism, high temperature resistance, corrosion resistance and magnetic properties. It is widely used inspecial, machinery manufacturing, electrical and electronic, chemical, ceramic and other industrial fields. In 2015, the world produced 123,800 tons of cobalt ore, and Congo (gold) produced 63,000 tons of cobalt ore, accounting for more than 50%. China only produced 7,700 tons, accounting for 6.2%. For China, cobalt is a scarce resource. Therefore, it is more and more economical to recycle and reuse cobalt from used batteries; lithium is the main element in power lithium batteries, and lithium resources are widely distributed in nature. However, the lithium resource extraction process industry has higher barriers.

As the demand for new energy vehicle drives is expanding, more and more companies are paying attention to lithium battery recycling, and recycling batteries through batteries to produce batteries with energy savings ranging from 70% to 90%. Recycling raw materials through batteries, producing batteries, has an absolute advantage in energy saving and emission reduction, and its macro level of economics is self-evident.

Third, power battery recycling channel analysis

After the power battery is decommissioned from the car, the charging and discharging performance cannot meet the power demand of the vehicle, but the chemical composition inside the battery has not changed, and can be applied to a place lower than the electric energy requirement of the car, using energy storage or related power supply. Base stations and street lights, low-speed electric body, etc., and then finally enter the recycling system after being eliminated. In summary, it is divided into two loop processes:

1 ladder use:

The battery capacity is reduced, so that the battery cannot make the electric vehicle operate normally, and it can still be used in other ways, for example, for power storage. (Note: the battery itself has not been scrapped)

2 dismantling and recycling:

The battery cannot be used anymore because the battery capacity is seriously depleted. Only the battery is recycled, and the renewable resources with valuable value are recovered.

The Chinese government has explicitly adopted a system of extension of producer responsibility. However, the implementation of this system has not yet been grasped. The recycling channel has not yet been established, which is a key issue that is urgently needed to be solved.

There are currently channels:

1 recycling small workshop

The location is wide and the recycling cost is low. However, these small workshops do not have technical safeguards and are prone to security risks.

2 Professional recycling Company

With advanced technology and equipment, standardized technology and comprehensive strength, it is a backbone enterprise for power battery recycling. But how do you ensure that these businesses are profitable? The market has not yet grown up, how to implement government policies, etc., but further research.

3 Waste Materials Recycling Association

The Waste Materials Reuse Association has a large number of member units, a wide range of contacts, and a relatively complete recycling network. However, at present, such organizations have not carried out the power battery recycling business. How to rationally layout the power battery recycling market? How to regulate it in a standardized way? There is still a lot of work to be done.

Fourth, the recycling of waste lithium ion battery technology

According to different extraction process classification, the recycling technology of lithium ion batteries can be divided into three categories:

(1) Dry recovery technology

It mainly includes mechanical sorting method and high temperature pyrolysis method (or high temperature metallurgy method), see Table (1). The dry recovery process is short, and the recovery is not targeted, which is the initial stage of metal separation and recovery. Mainly refers to the method of directly recovering materials or valuable metals without passing through a medium such as a solution, mainly by physically sorting and high-temperature pyrolysis, crushing the battery and classifying the coarse mesh, or pyrolyzing to remove the organic matter for further use. The elements are recycled.

(2) Wet recycling technology

The wet recycling technology is more complicated, as shown in Table (2), but the recovery rate of each valuable metal is relatively high. It is currently the main technology for disposing of used nickel-hydrogen batteries and lithium-ion batteries. The wet recovery technology uses various acid-alkaline solutions as a transfer medium to transfer metal ions from the electrode material to the leaching solution, and then ion-exchange, precipitation, adsorption, etc., to remove metal ions from the solution in the form of salts, oxides, and the like.

(3) Bio-recycling technology:

At present, the research on bio-recycling technology has just started, and it is the ideal direction for the development of lithium ion battery recycling technology in the future. Bio-recycling technology is characterized by low cost, low pollution, and reusability. It mainly utilizes microbial leaching to convert a useful part of the system into a soluble compound and selectively dissolve it to obtain a solution containing an effective metal, thereby separating the target portion from the impurity portion, and finally recovering a valuable metal such as lithium.

The entire recycling process is generally divided into four parts: (1) pretreatment part; (2) electrode material repair; (3) valuable metal leaching; (4) chemical purification.

The first step: the pretreatment process, the purpose of which is to initially separate and recover the valuable part of the old lithium ion battery, and efficiently and selectively collect the high value added parts of the electrode material, so as to facilitate the subsequent recovery process. The pretreatment process generally combines crushing, grinding, screening, and physical separation.

The second step: material separation. The mixed electrode material of the positive electrode and the negative electrode is obtained by enrichment in the pretreatment stage. In order to separate and recover valuable metals such as Co and Li, selective extraction of the mixed electrode material is required. The process of material separation can also be carried out according to dry recovery, wet recovery and biological recovery.

The third step: chemical purification. The purpose is to separate and purify and recover various high value-added metals in the solution obtained by the leaching process.

Summary

1 Lithium-ion batteries are more environmentally friendly than lead-acid batteries, but they are also polluting the environment. In the face of large-scale power battery decommissioning, the basic ways of utilization are: first, the use of ladders; second, the recycling of used lithium-ion batteries.

2 The recycling technology of waste lithium-ion batteries is mature, so don't worry too much.

3 Development of new energy vehicles, first, the Chinese government's response to the increasing dependence of steam (chai) oil on the externalities; second, lithium-ion batteries are more environmentally friendly than lead-acid batteries; third, as the lithium ion battery produces the environmental protection question, we have mature technology to be possible to deal with.

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