The phenomenal growth of new-energy cars in China, thanks to vigorous governmental promotion, has spawned a problem: how to dispose of used car power batteries whose amount is expected to skyrocket.
China's new-energy car market began to take off in 2012, with the annual output having exceeded 500,000 mark in 2016, which is estimated to top 700,000 in 2017. Given five to eight years of life for car batteries, amount of used power batteries is expected to hit 248,000 tons in 2020. Disposal of the huge amount of used batteries has emerged as a major problem, as only less than 10,000 tons of such batteries were dismantled and recycled in 2016. The phenomenon also represents serious waste of resources, as market potential for recycling of used car batteries, mainly from the retrieval of such metals as cobalt, nickel, manganese, lithium, iron, and aluminum, is estimated at over 5.3 billion yuan in 2018, which will top 10 billion yuan in 2020 and 25 billion yuan in 2023.
Recycling of used car batteries is an imperative for China, given the enormous polluting threat of positive electrode and electrolyte contained in batteries and serious dearth of cobalt and other precious metals, for which China relies on import heavily. Fortunately, the National Engineering Center of Advanced Energy Storage Materials has made major inroads into the problem, as it has successfully conducted several tests for retrieving precious metals from used batteries via hydrometallurgy and pyrometallurgy and proved feasibility for the commercialization of the two technologies.
With approval of the National Development and Reform Commission, the National Engineering Center of Advanced Energy Storage Materials has been established by a number of units jointly, including Corun New Energy, Central South University, Jinchuan Group of International Resources, and Hunan Reshing New Material Co., Ltd. Headed by Dr. Zhong Faping, the R&D team consists of two members of the Chinese Academy of Sciences, three members of the Chinese Academy of Engineering, two distinguished Yangtse River scholars, and near 20 experts with national-level outstanding contributions. It is the only national-level engineering center for advanced energy storage technology and key energy-storage materials.
Hydrometallurgy features dismantling and immersion of used batteries before retrieval of precious metals. The National Engineering Center has developed high-performance and safe fully automated battery dismantling equipment, for which it has applied for four patents.
The dismantling equipment dismantles round batteries into five kinds of materials, namely steel cases, iron, powdered active materials, nickel, and diaphragm, while square batteries are also dismantled into five kinds of materials, namely iron, powdered active materials, nickel, diaphragm, and plastic cases. Among them, iron cases and iron can be sold directly, while powdered active substances and nickel are materials for immersion and retrieval process. With capacity of 300 kg/h, the equipment can retrieve over 99.7% of nickel, cobalt, and rare earth, minimizing recycling cost.
The National Engineering Center has set up an experimental immersion-retrieval production line and has applied for six patents for hydrometallurgy. The production line is capable of retrieving and recycling nickel, cobalt, and rare earth from dismantled battery-cell materials, including nickel, powdered active substances, and rare earth.
Recycling quality is trustworthy, as experimental processing of multiple batches of 50 Kg used batteries show that nickel sulfate and cobalt chloride recycled by hydrometallurgy meet national quality standards, while recycled rare-earth salt can be sold directly, as it meets industrial standard.
Pyrometallurgy supplements hydrometallurgy
Via exploration of various conditions, including pretreatment method, melting temperature, and temperature-preservation time, the National Engineering Center has settled on pyrometallurgy, capable of recycling more than 97% of nickel and cobalt from used batteries, for which it has applied for six patents. Nickel sulfate and cobalt chloride retrieved with pyrometallurgy can be processed into nickel and cobalt products via hydrometallurgy.
The National Engineering Center aims to transform the car-battery crisis into a precious business opportunity and will continue to seek technological breakthrough to perfect the power-battery recycling system.