Properly utilizing spent lithium-ion battery packs is crucial to preventing environmental pollution. With the large-scale deployment of lithium-ion batteries in new energy vehicles and energy storage markets, many lithium-ion battery packs are entering their retirement phase this year. Improper recycling and disposal can lead to environmental pollution. The environmental problems caused by spent lithium-ion batteries have attracted widespread attention worldwide. While lithium-ion batteries are considered a relatively environmentally friendly energy storage method, the question remains: do discarded lithium-ion batteries actually cause environmental pollution?
There is very little recycling of lithium-ion battery packs on the market. Firstly, lithium-ion battery packs themselves produce relatively little pollution, so people don't pay enough attention to this; secondly, the returns from lithium battery recycling are low. As a result, lithium-ion batteries do not have the large-scale recycling applications that lead-acid batteries do.
1. Current Status of Waste Lithium-ion Battery Packs
In reality, very few companies actually recycle and reuse waste lithium-ion battery packs. This is because most companies are small-scale operations with outdated production equipment and technology. Therefore, their existence is largely exploratory, without actual production capacity, and they don't actually handle waste battery disposal. Currently, the most common method for disposing of waste lithium-ion batteries in my country is to mix them with other solid waste and then incinerate them, causing severe environmental pollution. With the continuous development of the lithium-ion battery industry, some domestic experts have proposed new methods for disposing of waste lithium-ion battery packs.
Some have proposed using machinery to shred waste lithium-ion batteries, then using vibration and sorting methods to classify the waste lithium-ion batteries. After classification, positive and negative electrode materials, electrode active materials, graphite, and other electrode active materials are selected. The electrode materials are then placed in a muffle furnace at 500 degrees Celsius for heat treatment, and then the lithium and cobalt oxides are separated and recycled using flotation methods.
Chen Liang et al. used H₂SO₄ + H₂O acid to leach the electrode material, and also used N₂O₂ to extract copper. They precipitated aluminum with NaOH solution, followed by further leaching to completely precipitate it, forming nickel-cobalt-manganese carbonate. Experiments showed that the leaching rates of nickel, cobalt, and manganese were 98%, 97%, and 96%, respectively. In summary, the recoveries of nickel, cobalt, and manganese were all above 5%, indicating high recovery value and effectiveness.
Xu Yuan et al. used an extraction method to effectively separate spent lithium cobalt oxide batteries. In this process, firstly, acid leaching was used to separate metal ions from the cathode material. Then, impurities were removed using P2O4 extraction to remove Fe3+, Al3+, Ca2+, Cu2+, and Mg2+ ions. However, Li2+ and Co2+ ions remained in the water. Next, P0 was used to remove these two ions. Simultaneously, HCl solution was used for back-extraction of CoCl2 from the organic cobalt-rich material. This two-stage back-extraction method achieved complete ion separation, leaving lithium ions in the water. Li2CO3 was then obtained by precipitating lithium ions using Na2CO3.
In summary, my country produces a large quantity of lithium-ion battery packs and consumes a significant amount of lithium-ion batteries. While there is considerable public attention to the recycling of lithium-ion battery packs, insufficient emphasis has been placed on the recycling and reuse of lithium-ion batteries themselves and resource regeneration. Currently, lithium-ion batteries are typically disposed of with other general waste. Furthermore, a lack of understanding of proper recycling methods prevents the effective utilization of recycled lithium-ion batteries.
2. Discharge treatment and manual disassembly of used lithium-ion battery packs
Discarded lithium-ion batteries usually still contain residual charge. If the residual charge is not discharged during the processing of lithium-ion batteries, fires and explosions can easily occur during battery disassembly. Therefore, before testing discarded lithium-ion batteries, they must be discharged first.
There are generally two methods for disposing of waste lithium-ion batteries: physical and chemical. Physical discharge primarily relies on an external load to discharge the battery. This involves connecting the battery to an external resistor, allowing the remaining charge to dissipate through heat release. However, this method is suitable for discharging small numbers of batteries. Pretreatment with sodium chloride solution is easy to operate, convenient, simple, and relatively economical. It also avoids secondary pollutants and is therefore widely used for discharging waste lithium-ion batteries.
During the experiment, the waste lithium-ion batteries were first placed in saturated salt water and discharged for 10 minutes. Short-circuiting the positive and negative electrodes completely released the charge in the batteries. After discharge, the batteries were placed in a drying oven at a temperature below 60°C for 10 hours. The outer casing of the lithium-ion batteries was then manually disassembled to obtain the battery core. The plastic film of the lithium-ion battery pack and the positive and negative electrodes were then manually sorted to obtain the positive electrode material.
3. What kind of pollution do used lithium-ion battery packs cause to the environment?
Substances from discarded lithium-ion batteries can still cause pollution from heavy metals such as nickel and cobalt (including arsenic), fluorine, organic matter, dust, and acids and alkalis when they enter the environment. The electrolytes and their conversion products from discarded lithium-ion batteries, such as LiPF6, LiAsF6, LiCF3SO3, HF, and P2O1, as well as the solvents and their decomposition and hydrolysis products, such as DME, methanol, and formic acid, are all toxic and hazardous substances. Therefore, discarded lithium-ion batteries should be sent to qualified facilities for proper disposal and should not be disposed of indiscriminately.
4. How to effectively recycle and reuse spent lithium-ion batteries?
Early research and accumulation for industrialization are crucial. Currently, in the recycling of power lithium batteries, "cascade utilization" is considered by the government and industry insiders to be a greener and more environmentally friendly approach, which can not only maximize the value of the product but also maximize the benefits of the circular economy.
At the national level, relevant support policies, industry norms, and standards for the cascade utilization of power lithium-ion batteries are being actively formulated.
A full lifecycle monitoring system for lithium-ion batteries should be established to assess their health status in real time. Battery evaluation and monitoring should be integrated throughout their entire lifespan, rather than waiting until they are no longer usable before testing and screening.
In conclusion, with increasing environmental awareness, the environmental pollution and proper disposal of used lithium-ion battery packs have garnered widespread attention. Therefore, the potential environmental pollution from used lithium-ion batteries is becoming increasingly serious, highlighting the growing necessity for strengthening waste battery management. Proper disposal and management of waste batteries is both essential and urgent. Companies should adopt appropriate recycling technologies to prevent resource waste and achieve sustainable development goals.
