Properly utilizing spent lithium battery packs is crucial to avoiding environmental pollution. With the large-scale deployment of lithium batteries in new energy vehicles and energy storage markets, many lithium 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 batteries have attracted widespread attention worldwide. While lithium batteries are considered a relatively environmentally friendly energy storage method, the question remains: do discarded lithium batteries actually cause environmental pollution?
There is very little recycling of lithium battery packs on the market. Firstly, lithium 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. This has resulted in lithium batteries not having the large-scale recycling applications of lead-acid batteries.
1. Current Status of Waste Lithium Battery Packs
In reality, very few companies recycle and reuse waste lithium battery packs. This is because most companies are small-scale operations with outdated equipment and technology. Therefore, these businesses are mostly in the exploratory stage and haven't actually entered production, meaning they don't handle waste battery disposal. Currently, the most common method for disposing of waste lithium 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 battery industry, some domestic experts have proposed new methods for disposing of waste lithium battery packs.
Some have proposed using machinery to shred waste lithium batteries, then using vibration and sorting methods to classify the waste lithium 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.
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 is used to separate metal ions from the cathode material. Then, impurities are removed using P2O4 extraction to remove Fe3+, Al3+, Ca2+, Cu2+, and Mg2+ ions. However, Li2+ and Co2+ ions remain in the water. Next, P0 is used to remove these two ions. Simultaneously, HCl solution is used for back-extraction of CoCl2 from the organic cobalt-rich material. This two-stage back-extraction method achieves complete ion separation, leaving lithium ions in the water. Li2CO3 is obtained by precipitating lithium ions using Na2CO3.
In summary, my country produces a large quantity of lithium battery packs and consumes a significant amount of lithium batteries. While there is considerable public attention to the recycling of lithium battery packs, insufficient emphasis has been placed on the recycling and reuse of lithium batteries themselves and resource regeneration. Currently, lithium batteries are typically disposed of with other general waste. Furthermore, a lack of understanding of proper lithium battery recycling methods prevents the effective utilization of recycled lithium batteries.
2. Discharge treatment and manual disassembly of used lithium battery packs
Discarded lithium batteries usually still contain residual charge. If this residual charge is not discharged during the processing of lithium batteries, it can easily cause fires and explosions during the disassembly process. Therefore, it is necessary to discharge discarded lithium batteries before conducting any tests on them.
There are generally two methods for disposing of waste lithium 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 does not produce secondary pollutants and is therefore widely used for discharging waste lithium batteries.
During the experiment, the waste lithium 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 lithium battery casing was then manually disassembled to obtain the battery core. The plastic film of the lithium battery pack and the positive and negative electrodes were then manually sorted to obtain the positive electrode material.
3. What kinds of pollution do used lithium 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 batteries should be sent to qualified facilities for proper disposal and should not be disposed of indiscriminately.
4. How to effectively recycle and reuse lithium batteries?
Early research and accumulation for industrialization are crucial. Currently, in the recycling of power batteries, "cascade utilization" is considered by the government and industry professionals 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 batteries are being actively formulated.
A full lifecycle monitoring system for lithium batteries needs to be established to assess the battery's health status in real time. Battery evaluation and monitoring should be integrated throughout the entire battery's lifespan, rather than waiting until the battery is phased out before testing and screening.
In conclusion, with increasing environmental awareness, the environmental pollution and proper disposal of used lithium battery packs have attracted widespread attention. Therefore, the potential environmental pollution from used lithium batteries is becoming increasingly serious, highlighting the growing necessity for strengthening waste battery management. Proper disposal and management of waste batteries is both necessary and urgent. Enterprises should adopt reasonable recycling technologies to avoid resource waste and achieve sustainable development goals.
