Application of Nickel in New Energy Battery Technology

At present, the electric vehicle market is expected to become the largest and most important market for lithium-ion batteries. Although all participants in the value chain strongly hope to increase the sales of electric vehicles, the rapid popularization of electric vehicles has been hindered due to high purchase costs and mileage anxiety, lack of charging stations and hidden fire safety hazards. In order to reduce energy consumption and reduce greenhouse gas emissions, major countries in the world are promoting electric vehicles (EV). "Nickel" can significantly increase the energy density of lithium-ion batteries, making high-nickel lithium-ion batteries the current preferred technology for electric vehicles.

Battery recycling in the automotive industry

The lithium battery industry is making large-scale investments in research and development and new production facilities, which are directly related to the development of electric vehicles (EV), which has led to changes in the main chemical composition of batteries. Hybrid electric vehicles (HEV) generally use NiMH batteries, while plug-in hybrid electric vehicles (PHEV) and pure electric vehicles (BEV) use lithium-ion batteries because of their high energy density and other excellent properties. .

Once PHEV and EV enter the mass market, they will have a huge impact on the battery recycling industry. Battery recycling companies are investing in larger-scale recycling facilities to process the lithium-ion batteries recovered from these vehicles in preparation for future demand. When the battery performance drops below the allowable use level of the vehicle, the battery may still be suitable for secondary use in the field of power storage. Finally, when the battery performance is insufficient, it needs to be disposed of. On the one hand, batteries are recycled to protect the environment, and on the other hand, because they contain valuable recyclable materials. The economic incentive for battery recycling is the value of the lithium metal oxide used in the battery cathode: cobalt, nickel, manganese, and combinations thereof, as well as phosphorus and iron. Copper, aluminum and steel are also components of the unit cell structure. The properties of the battery vary with the cathode material, and many different chemical compositions are used.

The important cathode materials in lithium-ion batteries are nickel manganese cobalt (NMC) and nickel cobalt aluminum (NCA), and the content of nickel chemical substances is 33% to 80%. NMC is used in various devices and electric vehicles. NCA is used in the 18650 Panasonic cell batteries of Tesla Motors, and is mixed with lithium manganese oxide (LMO) in other electric vehicles. Other main cathode materials are LiCoO2, LiMn2O4 and LiMPO4.

However, the value of recycled unit cell materials varies with cathode composition and recycling process. Most lithium-ion batteries today use cobalt oxide-based cathodes, and the recovery of elemental cobalt promotes process economic research. The current method of recycling batteries with low cobalt content (such as many types of batteries developed for vehicles) is not attractive, but a new recycling process is being developed to recover cathode active materials (including the lithium contained therein), which can It is reused in batteries, and the value is much higher than its constituent elements, but the quality of recycled materials must be guaranteed.

Along with technological progress, the regulatory environment in the battery industry is constantly changing and tightening. The EU Battery Directive is currently under review, which stipulates that batteries must be recycled. China's regulations stipulate that the responsibility for recycling car batteries is borne by car manufacturers. Currently, the United States does not have uniform regulations on battery recycling, and current regulations are formulated at the state level. It is expected that countries around the world will formulate more relevant regulations.

Due to the difficulties faced by the collection system, it is estimated that only about 10% of old lithium-ion batteries enter the collection system and are eventually recycled, and most of these batteries come from various portable electronic products.

Other batteries currently collected and recycled are mainly NiMH batteries, including batteries from HEV, which contain 23% nickel, 4% cobalt, 7% rare earth metals, 36% steel, 18% plastic, 9% electrolyte, 2% other metals and 1% polytetrafluoroethylene (PTFE). Toyota Prius is the world's leading HEV in sales. Toyota is also committed to adopting NiMH batteries because it is regarded as a mature and reliable battery technology. Considering that the annual sales of HEVs in the past five years were 1.5 to 1.8 million units and the battery life was 10 years, the number of NiMH car batteries that need to be recycled is still increasing.

Global PHEV sales reached 250,000 units, of which China took the lead (with a share of 29%) due to the promulgated strong incentive policies. Incentive policies have also made China a leading market for electric vehicles. In 2016, the global sales of electric vehicles were approximately 500,000, of which China accounted for 55% of the global market share. The industry predicts that sales will continue to climb in the next five years, which means that battery recycling companies will dispose of more and more lithium-ion batteries in the next few decades.

Synergistic benefits of nickel and steel in batteries

Nickel plays an important role in many battery systems on the market today, providing convenience to our lives and freeing us from worrying about finding power outlets.

Regardless of the chemical composition of the battery, nickel still plays a little-known but very important role in battery production-combined with steel in the cylindrical battery case and protective cover. This nickel-plated steel structure ensures that battery power can be efficiently transferred to the device when needed.

The cylindrical battery case strongly guarantees the integrity of the battery. The strength of steel can adapt to volume expansion and contraction during charging (discharging), while cylindrical nickel-plated steel battery cases are widely used in disposable and rechargeable battery systems.

Electroplating a few microns of nickel on the top and bottom of the steel strip can form a lower contact resistance. Tata Steel Electroplating Company has perfected this technology with the most advanced nickel plating production line. The coil is heat treated after plating. This treatment reduces the contact resistance and enhances the adhesion of the subsequent high-speed shell making process. In addition to electrical characteristics, nickel can also provide good corrosion protection to the corrosive lye inside the battery, thereby inhibiting the gas evolution phenomenon that allows the structure to withstand huge pressure during its life.

When producing battery cases, manufacturers use high-speed precision stamping machines to change the shape of the steel strip through multiple stretching processes. Then, the finished battery case is shipped to battery manufacturers around the world.

In addition to its excellent properties in deep drawing and battery performance, nickel also plays an important role in battery assembly because it exhibits excellent welding characteristics.

"Although people are accustomed to batteries, no matter how much emphasis is placed on the role of nickel and nickel-plated steel in the performance and reliability of various battery systems, it cannot be overstated." said Dr. Marcel Onink, Director of Commercial Innovation at Tata Steel Electroplating Company. , The number of alkaline batteries is the largest. However, with the strong growth of electric vehicles in the future, this successful combination is expected to continue to glow. No matter what the final chemical composition of the battery, its packaging is most likely to be nickel-plated steel This proven concept."