Materials are the key core driving the development of power batteries. In the era of high nickel, what kind of changes the material supply chain system is showing, how to balance safety, cost, and performance, and the progress of industrialization of new materials, are all topics that the lithium battery industry is paying close attention to.
In Power Battery Special Session 3 of “Li Yuanheng • 2019 Annual Lithium Battery & Electric Vehicles Annual Conference”, Liang Shishuo, senior general manager of Hongpeng New Energy Battery Research Institute, Chen Yudi, executive vice president of Norder, Xia Wenjin, general manager of Suzhou Lidun, Shenzhen Snow Chairman Bao Haiyou, Dr. Wang Shaohui, R & D Director of Onestone, Zhao Jun, President Assistant of Rongbai Technology and General Manager of Strategic Management Center, etc. participated in the round-table dialogue on “Responding to High Energy Density Material Innovation”.
As a wholly-owned subsidiary of Baoneng Group focusing on new energy power batteries, Liang Shishuo, senior chief of Hongpeng New Energy Battery Research Institute, said that Hongpeng power batteries are positioned in the high-end market, and the technical route includes soft packs and squares. The material selection is mainly based on high-nickel materials and silicon carbon. The company is also developing solid-state, solid-liquid mixed system batteries.
Liang Shishuo, Senior Chief Teacher of Hongpeng New Energy Battery Research Institute
"The company has multiple technical systems, high nickel 811 system, fast charge high power system and solid state system, etc. At present, the high nickel 811 system is advancing faster." Liang Shishuo added.
Among the new players who have entered the field of power batteries with huge amounts of capital, Hongpeng New Energy is a representative one. The company's choice of technical route and material system to the formation of the core competitiveness of the final product also determines to a certain extent whether it can stand out in the next fierce market competition.
From the perspective of development trends, high-energy-density systems have become an important set of power battery development, but only time and speed, fast and slow development. In terms of materials, how have materials companies made breakthroughs and efforts in technology, safety, performance, and quality control?
In terms of positive electrode materials, under the requirements of increasing energy density and reducing costs, the commercialization of NCM811 materials is accelerating, which in turn generates strong demand for high nickel materials.
Zhao Jun, President Assistant of Rongbai Technology and General Manager of Strategic Management Center
Zhao Jun, president assistant and general manager of strategic management center of Rongbai Technology, said that Rongbai Technology is half a position ahead in the field of high nickel materials. Judging from the industrialization process, cylinders such as BAK, Far East Foster and some high-end 3C battery companies are already using high nickel systems. Square is currently only used by one head battery company.
Rongbai Technology's NCM811 high-nickel cathode material is already a mature product, and this year's shipments rank first in the industry. In the next two to three years, Rongbai Technology will still adhere to the high-nickel product line and maintain a leading market share, making it the company's main source of performance.
In terms of anode materials, silicon-carbon anode materials are considered to be the key to the industrialization of the next generation of high specific energy power batteries, but in large-scale applications, there are still short boards with low first-effect, volume expansion, and fast decay cycles.
Bao Haiyou, Chairman of Shenzhen Snow
Bao Haiyou, the chairman of Shenzhen Snow, said that the main problems of silicon-based anode materials at present include volume expansion, pulverization of materials, failure of conductive networks, and repeated growth of SEI. The above problems will cause problems such as poor battery safety performance and poor rate performance. Now the silicon used in the industry is generally 8% -10%.
In response to the above problems, Shenzhen Snow uses a low-temperature chemical method in the preparation of nano-silicon, and its technical advantages are safety and environmental protection, low energy consumption, low cost, and large-scale. The first charge capacity of the nano-silicon material prepared by this method is 449 mAh / g, the first effect is 91.9%, and the capacity retention rate is greater than or equal to 95% after 100 weeks of cycling, and the prospect is promising.
With regard to separator coating materials, with the increasingly strict control of magnetic foreign bodies by power battery manufacturers, the requirements for battery performance and quality have continued to rise, and the application of ceramic powder materials for lithium battery separator coatings has become a general trend.
Dr. Wang Shaohui, R & D Director of Onestone
Dr. Wang Shaohui, director of research and development of Yishitong, pointed out that compared to alumina, boehmite has the advantage of low hardness, which can reduce the risk of equipment wear and foreign objects; the same weight is 25% more area; Internal resistance is small; low energy consumption, the production process is more environmentally friendly; and the water absorption of boehmite is only half that of alumina.
In terms of quality control of ceramic powders, Yishitong has achieved four aspects: one is the layered structure characteristics, which can control the preparation of flaky particles; the other is the random accumulation of flaky particles, which has a high degree of tortuosity in the channels and prevents lithium The thickness of the dendrite penetration growth is small; the third is the smaller the particle size, the smaller the thickness that prevents penetration of the dendrite; the fourth is the adjustment of the particle size to meet the requirements of different thicknesses.
As for the aluminum-plastic film, as the key material of the soft pack battery, the domestic power battery aluminum-plastic film is still monopolized by Japanese and Korean material companies.
Xia Wenjin, general manager of Suzhou Lidun
Xia Wenjin, general manager of Suzhou Lidun, said that in order to wear aluminum plastic film with "red" clothes, it is necessary to take a new technical route that is different from the traditional, and to fully realize the localization of materials in order to break the last barrier to the localization of power battery materials .
In response to this, Suzhou Lidun independently developed a third technical route different from the Japanese and South Korean dry and thermal methods-a microwave non-polar physical anchoring solution. Using the "nail nail" principle, the micro-anchors are driven into the interfaces of nylon, PP, and aluminum foil, respectively, and then the anchors at each interface are connected by microwave irradiation to form a chemical anchor net, which produces excellent deep-drawing, high Aluminum, plastic film products with barrier properties, insulation properties, flame retardancy and corrosion resistance.
In terms of copper foil, mainstream energy battery companies have completed the fast switching of thin and light copper foils under the requirements of increasing energy density. The market share of 6μm ultra-thin lithium battery copper foil has increased rapidly, and the thinner 4μm copper foil has also entered mass production .
Chen Yuchen, Executive Vice President of Nord
Chen Yukun, Executive Vice President of Norder Group, believes that the switch to thin copper foil for power battery companies is an important trend in the future. In 2019, 6μm copper foil has become the mainstream of the market. By 2020, it should be 4μm copper foil. However, the application of lithium battery copper foil is not as thin as possible, it is necessary to ensure the safety of the battery.
At present, 4.5μm ordinary tensile copper foil of NORD has begun to supply customers in small quantities; samples of high tensile products have been submitted, and customers are verifying the introduction. Copper foil with a tensile strength of 6μm ≥45KG has begun to supply to customers, and the elongation can be ≥8%. Perforated copper foil has achieved batch stable production, mainly used in solid-state batteries, which can help increase energy density by 20%.