The recycling and disposal of used batteries has always been a major concern. Currently, there are three main recycling methods used, which we will briefly introduce below.
Metallurgical methods are commonly used technologies for recycling waste batteries, mainly divided into pyrometallurgical methods and hydrometallurgical methods. Among them, pyrometallurgical methods mainly use high temperatures to break down the outer shell, thereby recovering the metal compounds in the battery. Relatively speaking, it is a relatively simple method in terms of technology and construction process for lithium-ion battery recycling. However, it also has certain defects and limitations. Although it can effectively recycle lithium-ion batteries, the resulting air pollution problem has become a major challenge in subsequent treatment. Strict filtration treatment is required for the waste generated during the recycling process, which increases the technical difficulty of the work.
Secondly, there is hydrometallurgy. Unlike pyrometallurgy, hydrometallurgy uses mechanical methods to break down the outer shell, thereby recovering metal compounds. When recovering metal compounds from waste batteries, in addition to the commonly used precipitation method, ion exchange and adsorption methods are also used. This can effectively improve the purity of the metal. Therefore, hydrometallurgy has a wide range of applications, especially for lithium-ion batteries with high metal recovery requirements, where hydrometallurgy is currently the best choice.
Besides hydrometallurgical and pyrometallurgical methods, there is another method called bioleaching. Bioleaching uses bacteria to effectively recycle lithium-ion batteries and is a relatively new technology for waste battery recycling. It boasts high recycling efficiency and low cost, thus attracting considerable attention. However, compared to the cultivation of bacteria, bioleaching requires a long cultivation time, making it unsuitable for the current state of waste lithium-ion battery recycling. Nevertheless, in the long run, bioleaching will inevitably replace hydrometallurgical methods and become the mainstream technology for waste lithium-ion battery recycling.
There are generally three common methods for disposing of used batteries internationally: solidification and deep burial, storage in abandoned mines, and recycling.
1. Solidify and bury deeply, store in abandoned mine shafts
For example, a French factory extracts nickel and cadmium from it, using the nickel in steelmaking and the cadmium in battery production. Other types...
Used batteries are typically transported to specialized landfills for toxic and hazardous waste, but this practice is not only too expensive but also wasteful.
Because it still contains many useful substances that can be used as raw materials.
2. Recycling
(1) Heat treatment
Switzerland has two factories specializing in processing and utilizing used batteries. Battläck's method involves grinding up the batteries and heating them in a furnace. This process extracts the volatilized mercury, and at higher temperatures, zinc also evaporates; zinc is another valuable metal. Iron and manganese fuse to form ferromanganese alloy, needed for steelmaking. This factory can process 2,000 tons of waste batteries annually, yielding 780 tons of ferromanganese alloy, 400 tons of zinc alloy, and 3 tons of mercury. The other factory directly extracts iron from the batteries and sells the mixture of manganese oxide, zinc oxide, copper oxide, and nickel oxide as scrap metal. However, the heat treatment method is expensive, and Switzerland also mandates a small processing fee for each battery buyer.
(2) Wet treatment
A wet processing plant is under construction near Magdeburg. Here, all types of batteries, except lead-acid batteries, are dissolved in sulfuric acid. Various metals are then extracted from the solution using ion-exchange resins. The raw materials obtained in this way are purer than those obtained through thermal treatment, thus commanding a higher market price. Furthermore, 95% of the various substances contained in the batteries can be extracted. Wet processing eliminates the sorting step (which is manual and increases costs). This Magdeburg plant has an annual processing capacity of 7,500 tons. While its cost is slightly higher than landfill methods, valuable raw materials are not wasted, and there is no environmental pollution.
Discarded "large batteries"
—How should the power batteries be disposed of?
Secondary use: This refers to the process of restoring the functionality of a product that has reached its original design lifespan through other methods, allowing it to be used in its entirety or partially restored. The principle is similar to the Nanfu battery commercials we saw as children: if a remote control battery couldn't be used on a car, it could still be used on the remote control.
Specifically, in the context of power batteries, cascade utilization refers to the reuse of retired batteries with a capacity of 40%-70% in areas such as backup power supplies and communication base stations after sorting, evaluation, and equalization technologies, thereby maximizing their value.
However, there are still some obstacles to the widespread promotion of tiered utilization:
(1) Battery quality issues
Not all retired batteries can be reused. Most of the retired power batteries on the market today are from the first batch of new energy vehicle power batteries put into the market. They have a short lifespan and a very low degree of standardization (battery size, model, production records and coding are not uniform). The batteries have poor consistency, and it is difficult to guarantee battery life and stability, which poses safety hazards.
(2) Cost issues
Retired batteries require several steps for reuse, including testing, dismantling, reassembly, and maintenance. However, China's battery recycling system is currently underdeveloped, and the technology for secondary use is still immature, all of which increase costs. According to data from the National Energy Information Platform, assuming the purchase cost of retired power batteries is $20/kWh and the utilization rate is 60%, the cost of battery recycling, dismantling, and reassembly is $71.7/kWh. If reusing a battery is less expensive than buying a new one, then there is even less market for secondary use.
(3) Policy access issues
Furthermore, policies regarding the cascade utilization of batteries are also evolving. The draft for public comment on the "Management Specifications for New Energy Storage Projects" stated that "before key breakthroughs are achieved in battery consistency management technology and a sound power battery performance monitoring and evaluation system is established, large-scale power battery cascade utilization energy storage projects should, in principle, not be newly constructed." Subsequent official documents relaxed these restrictions: "New power battery cascade utilization energy storage projects must adhere to the full life-cycle concept, establish a battery consistency management and traceability system, and all cascade utilization batteries must obtain safety assessment reports issued by qualified institutions."
