Batteries contain a variety of harmful substances, and improper disposal will have a huge impact on the environment.
A large number of retired batteries pose a potential threat to the environment, especially the heavy metals, electrolytes, solvents and various organic additives in power lithium-ion batteries. If they are not disposed of properly, they will cause great harm to soil and water, and the remediation process is time-consuming and costly. Therefore, there is an urgent need for recycling.
The following table lists the substances typically found in lithium-ion batteries. According to the 2011 U.S. Hazardous Substances List, Ni, Co, and phosphides, with scores exceeding 1000, are considered high-risk substances. If discarded lithium-ion batteries are disposed of using conventional waste treatment methods (including landfill, incineration, composting, etc.), the cobalt, nickel, lithium, manganese, and other metals, as well as inorganic and organic compounds, will inevitably cause serious pollution to the atmosphere, water, and soil, posing a significant hazard.
If substances from spent lithium-ion batteries enter the ecosystem, they can cause pollution from heavy metals such as nickel and cobalt (including arsenic), fluorine, organic matter, dust, and acids and alkalis. The electrolytes and their conversion products from spent lithium-ion batteries, such as LiPF6, LiAsF6, LiCF3SO3, HF, and P2O5, as well as the solvents and their analytical and hydrolysis products, such as DME, methanol, and formic acid, are all toxic and harmful substances that can cause personal injury or even death.
The key to the economic value of battery material recycling lies in the further exploration of the material's regeneration value and energy value.
This includes three aspects:
1. After lithium-ion batteries are retired from high-end electrical appliances, they can still meet the needs of some low-end electrical appliances, such as electric toys and energy storage facilities. The secondary use after recycling can give lithium-ion batteries more value, especially retired power lithium-ion batteries;
2. Even if the electrical properties cannot meet the requirements for more advanced applications, the relatively rare metals it contains, such as Li, Co, and Cu, still have recycling value;
3. Due to the significant difference between the energy required for the reduction of some metals and the energy required for metal regeneration, such as Al, Ni, and Fe, metal recycling has economic value in terms of energy consumption.
Different types of lithium-ion batteries contain different kinds of metals and their proportions. One ton of traditional consumer-grade lithium cobalt oxide batteries contains approximately 170 kilograms of cobalt metal, while the contents of copper, aluminum, and lithium are mostly similar. Therefore, overall, the recycling value of lithium cobalt oxide batteries is greater than that of other types, such as lithium iron phosphate batteries and ternary lithium-ion batteries.
Battery cells account for 36% of the cost of power lithium-ion batteries, and as much as 49% if gross profit is excluded; the cost of battery cells is even higher in consumer batteries. Within battery cells, the cost of cathode materials rich in metals such as nickel, cobalt, and manganese accounts for 45%.
Currently, the resource recycling process includes two stages: pre-treatment and post-treatment.
The preliminary solution involves discharging the used lithium-ion batteries in salt water, removing the outer packaging, and removing the metal casing to obtain the battery cells inside.
The battery cell consists of a negative electrode, a positive electrode, a separator, and an electrolyte. The negative electrode is attached to the surface of a copper foil, the positive electrode is attached to the surface of an aluminum foil, and the separator is an organic polymer. The electrolyte is attached to the surfaces of the positive and negative electrodes and is an organic carbonate solution of LiPF6.
The subsequent solution involves recycling high-value components from the various waste materials after dismantling, and carrying out battery material remanufacturing or repair. The technical methods can be divided into three categories: dry recycling technology, wet recycling technology, and biological recycling technology.
Dry recycling technology refers to the technology and methods for recovering various battery materials or valuable metals directly without the use of solutions or other media. It mainly includes mechanical sorting and high-temperature pyrolysis.
Dry thermal repair technology can perform high-temperature thermal repair on the crude products obtained from dry recycling, but the positive and negative electrode materials produced contain certain impurities and their performance cannot meet the requirements of new energy vehicle power lithium-ion batteries. It is mostly used in energy storage or small power lithium-ion batteries and is suitable for lithium iron phosphate batteries.
Pyrometallurgy, also known as incineration or dry metallurgy, removes organic binders from electrode materials through high-temperature combustion. Simultaneously, it causes oxidation-reduction reactions in the metals and their compounds, recovering low-boiling-point metals and compounds through condensation. Metals in the slag are recovered using methods such as screening, pyrolysis, magnetic separation, or chemical processes. Pyrometallurgy has relatively low requirements for the composition of raw materials, making it suitable for large-scale processing of complex batteries. However, combustion inevitably produces some waste gas that pollutes the environment, and the high-temperature processing places high demands on equipment, requiring additional purification and recovery equipment, resulting in high costs.
Wet recovery technology uses various acidic and alkaline solutions as transfer media to transfer metal ions from electrode materials to leachate. Then, through ion exchange, precipitation, adsorption and other means, the metal ions are extracted from the solution in the form of salts, oxides and other substances. It mainly includes three methods: hydrometallurgy, chemical extraction and ion exchange.
Wet recycling technology is relatively complex, but it has a high recovery rate for valuable metals such as lithium, cobalt, and nickel. The resulting metal salts and oxides have high purity, meeting the quality requirements for processing power lithium-ion battery materials. It is suitable for ternary batteries and is an important recycling method adopted by leading recycling companies at home and abroad.
Biological recycling technology primarily utilizes microbial leaching to convert the system's valuable components into soluble compounds and selectively dissolve them, thereby separating the target components from impurities and ultimately recovering valuable metals such as lithium, cobalt, and nickel. Currently, biological recycling technology is not yet mature, and key issues such as the cultivation of highly efficient microbial strains, excessively long cultivation cycles, and the control of leaching conditions still need to be addressed.
Currently, the more efficient and relatively mature wet recycling process is gradually becoming the mainstream technical route for specialized solutions. Leading domestic companies such as GEM and BEP Group, as well as leading international companies such as AEA and IME, have mostly adopted the wet technology route as a key technology for the recycling of valuable metal resources such as lithium, cobalt, and nickel.
The cathode material obtained by recycling valuable metals using wet processing technology has a higher specific capacity than the cathode material obtained by dry processing technology.
Compared to lithium iron phosphate batteries, ternary lithium batteries have a shorter lifespan. The cycle life of ternary lithium batteries is only 800-2000 times, and there are certain safety risks. They are not suitable for cascade utilization in complex environments such as energy storage power stations and backup power supplies for communication base stations.
However, since ternary lithium-ion batteries contain rare metals such as nickel, cobalt, and manganese, it is theoretically possible to achieve an economic benefit of approximately 42,900 yuan per ton by disassembling and extracting materials such as lithium, cobalt, nickel, manganese, copper, aluminum, graphite, and separators, which is economically feasible.
Taking ternary 523 batteries as an example, each ton of ternary batteries contains approximately 96, 48, 32, and 19 kilograms of nickel, cobalt, manganese, and lithium, respectively. Currently, the average recovery rate of nickel, cobalt, and manganese in the market can reach over 95%, while the recovery rate of lithium is around 70%. The market prices of metallic lithium, cobalt, electrolytic nickel, and electrolytic manganese are 900,000 yuan/ton, 600,000 yuan/ton, 100,000 yuan/ton, and 12,000 yuan/ton, respectively.
The metal salts such as nickel sulfate, cobalt sulfate, and manganese sulfate obtained from the recycling and processing of power lithium-ion batteries can be continuously processed into ternary precursors, which have significant added value potential.
Taking nickel sulfate processing as an example, the cost of recycling each ton of nickel through the recycling of waste lithium-ion batteries is less than 40,000 yuan, while the cost of processing directly from nickel ore is more than 60,000 yuan. The cost of obtaining metal raw materials through resource recycling is lower than the cost of directly mining, making the resource recycling of ternary batteries significant for cost reduction.
Considering that ternary lithium battery recycling companies resell the precious metals to downstream companies in the form of sulfates, the selling price should be lower than the market price of pure metals. Therefore, assuming a discount of 70% to the market price, the dismantling revenue of ternary lithium batteries would be 34,000 yuan/ton. Thus, the market size of ternary lithium battery dismantling alone is expected to reach 5.41 billion yuan by 2023.
In terms of costs, the cost of recycling ternary lithium batteries mainly consists of processing costs, various fees, and taxes.
The main components of processing costs include:
Material costs (waste batteries, liquid nitrogen, water, acid and alkali reagents, extractants, precipitants, etc.) are 20,000 yuan/ton;
Fuel and power costs (electricity, natural gas, gasoline consumption, etc.) are 650 yuan/ton;
Environmental remediation costs (waste gas and wastewater purification, as well as waste residue and ash disposal) are 550 yuan/ton;
Equipment cost (equipment maintenance fee, depreciation fee): 500 yuan/ton;
Labor costs (wages for operators, technicians, and transportation personnel, etc.) are 400 yuan per ton.
The allocated management expenses, including salaries of management personnel, and sales expenses, including sales personnel and packaging, are approximately RMB 400 per ton; value-added tax and income tax are RMB 4,000 per ton.
The total dismantling cost of ternary lithium batteries is 26,500 yuan/ton. Based on the above-mentioned revenue of 34,000 yuan/ton, the dismantling profit is 7,500 yuan/ton, and the corresponding net profit margin in 2023 is expected to exceed 1 billion yuan.
Through raw material recycling, metal elements such as nickel, cobalt, and manganese can achieve a recovery rate of over 95%, resulting in significant economic benefits. Resource recycling can produce nickel, cobalt, manganese, and lithium salts, and even further generate ternary cathode materials and precursors, which can be directly used in lithium-ion battery cell manufacturing, holding great significance for building a closed-loop industrial chain.
Lithium iron phosphate batteries: A huge market potential worth tens of billions of yuan for secondary use.
Regarding lithium iron phosphate batteries, the most widely used wet recycling method currently costs around 8,500 yuan per ton, while the revenue from precious metal recycling materials is only around 8,100 yuan. Therefore, the dismantling and recycling process results in a loss of approximately 400 yuan per ton.
Therefore, the key to recycling lithium iron phosphate batteries is not dismantling but secondary utilization. Secondary utilization can fully realize their residual value, maximize the circular economy, and reduce the construction cost of energy storage systems.
A circular system for tiered utilization
Secondary utilization refers to the reuse of retired power lithium-ion batteries after processes such as detection, screening, and recombination, in applications such as low-speed electric vehicles, backup power supplies, and energy storage where the operating conditions are relatively good and the requirements for battery performance are relatively low.
Currently, the key areas for cascade utilization are still energy storage and peak shaving.
The first step in the cascade utilization process is to screen retired power lithium-ion batteries. It is conservatively estimated that the cascade utilization rate of power lithium-ion batteries put into operation after 2014 can reach 60%-70%.
Then there is the string configuration, which uses a set of power lithium-ion battery packs removed from each electric vehicle as a separate unit, paired with a small to medium power energy storage inverter to form a basic energy storage unit. Multiple basic energy storage units are then integrated together to form a medium to large energy storage power system.
Thirdly, there is the management of charging and discharging. Taking my country Tower as an example, the current "peak shaving and valley filling" projects require about 8,800 kWh of reserve power for tower backup and peak shaving and valley filling stations (currently mainly using lead-acid batteries with short service life, low energy density, and low price). However, with the requirements of environmental protection and efficiency, the replacement of lead-acid batteries will open up a huge demand gap for the cascade utilization of power lithium-ion batteries.
Currently, the mainstream choice is the cascade utilization technology based on PACK (battery pack, i.e., a module composed of multi-level series and parallel batteries) + bMS (battery management system).
The PACK process is divided into three main parts: production, assembly, and packaging. Its core is to connect multiple individual cells in series and parallel through mechanical structures to form a battery pack.
The detailed operation process involves a high barrier to entry because it requires consideration of the mechanical strength and system matching of the entire battery pack. It involves the collaboration of a large number of mature technologies such as thermal management, current control and testing, module assembly design and computer virtual development.
The key function of a battery management system (bMS) is to intelligently manage and maintain each battery cell, prevent overcharging and over-discharging, and monitor the battery status in real time, thereby protecting the battery's lifespan.
A battery management system (bMS) is a collection of management, control, display, communication, and information acquisition modules. It serves as a link between the vehicle, the battery, and the entire battery system. For battery manufacturers, the bMS reflects their core technological competitiveness. For the secondary use of power lithium-ion batteries, the bMS determines the applicable scope, lifespan, and overall value of the reused batteries.
In a narrow sense, secondary use refers only to the reorganization and reuse of batteries. However, a secondary use and recycling system for lithium iron phosphate batteries has been established, encompassing a full-cycle, multi-level utilization of available resources: when a vehicle reaches the end of its service life (generally, the lifespan of a vehicle is longer than that of its battery), it will undergo the following processes:
(1) High-performance battery screening: Car manufacturers, car dismantling plants and some recycling companies will screen out batteries with high consistency and relatively good performance from the scrapped batteries through testing and other methods, and then group them or entrust other companies to group them into battery packs, and then sell them to downstream companies such as my country Tower for cascade utilization.
(2) Dismantling: Most batteries in poor condition and without direct use value will be collected by third-party recycling companies. The recycling companies will dismantle and reuse them using physical or wet methods, extracting raw materials such as copper, aluminum, and separators and selling them directly. The positive electrode material powder and negative electrode material powder of lithium iron phosphate batteries will enter the repair stage.
(3) Repair: The purpose of repair is to further purify the lithium iron phosphate material powder to obtain a higher selling price. At the same time, the batteries retired after cascade utilization will also undergo dismantling/repair processes to achieve multi-dimensional and multi-layered utilization.
In the entire recycling process, a typical recycling company has three profit points, namely...
(1) Selling batteries that are in good initial condition and can be used in a straight, tiered manner;
(2) Sell the dismantled raw materials;
(3) Sell repaired positive/negative electrode materials.
However, the secondary use of lithium-ion batteries currently faces challenges in both technology and commercialization. From a technical perspective, due to the poor consistency and varying lifespan of power lithium-ion batteries, the data from the bMS system will deviate from the actual condition of the batteries, thus posing challenges to safety and product quality during the secondary use process.
From a commercial perspective, on the one hand, the standardization of products currently used in cascade applications is relatively low; on the other hand, because battery models vary, the number of batteries required for assembly will be very large, resulting in relatively high costs for screening, assembly, and production. Only a few companies with mature technologies can obtain economic benefits.
Nevertheless, several industry leaders have already reached strategic cooperation agreements with downstream companies such as my country Tower for research and application. With the continuous introduction and implementation of various standards for power lithium-ion batteries, the consistency of batteries will be greatly improved, and the close cooperation will solve the problem of tiered utilization in the future.
From an economic perspective, the potential for the secondary use of lithium iron phosphate batteries is calculated.
Assuming that PACK+bMS technology is used for tiered utilization, the cost of PACK is approximately 0.3 yuan/Wh, the cost of bMS is approximately 0.1 yuan/Wh, the cost of recycling used lithium iron phosphate batteries is approximately 0.05 yuan/Wh, the total cost of tiered utilization of lithium iron phosphate batteries is approximately 0.45 yuan/Wh, and the revenue from tiered utilization is 0.6 yuan/Wh.
Assuming the energy density of lithium iron phosphate batteries is 110Wh/kg, and the energy of recycled batteries decays to 70%, the potential revenue from secondary utilization is expected to exceed 5 billion yuan in 2023.
Whether it's tiered utilization or dismantling, we can see a new blue ocean that will gradually open up in the next few years. Those who seize this opportunity will surely reap considerable rewards.
