Classification and market potential analysis of anode materials for lithium battery packs
The anode material mainly affects the first-time efficiency and cycle performance of lithium battery packs. The growing popularity of the new energy vehicle field has attracted a large number of domestic and foreign companies to go to the 'battlefield' one after another, and the market share of the negative electrode industry of lithium battery packs continues to increase. 1. The working principle of lithium ion battery The negative electrode of lithium ion battery is made by mixing negative active material carbon material or non-carbon material, binder and additives to make paste glue evenly applied on both sides of copper foil, and then dried and rolled into a paste. to make. The negative electrode material is the main body of lithium-ion batteries to store lithium, allowing lithium ions to be inserted and extracted during charging and discharging. When a lithium battery is charged, the lithium atoms in the positive electrode are ionized into lithium ions and electrons, and the lithium ions move to the negative electrode to synthesize lithium atoms with the electrons. During discharge, lithium atoms are ionized from the surface of the negative electrode in the graphite crystal into lithium ions and electrons, and lithium atoms are synthesized at the positive electrode. 2. Classification of anode materials for lithium battery packs The current domestic anode material products are mainly carbon materials and non-carbon materials. Among them, carbon materials can be divided into graphite-based carbon materials and amorphous carbon materials. The most common application of graphite-based carbon materials is natural stone. Ink and artificial graphite; non-carbon materials mainly include tin-based materials, silicon-based materials, nitrides, and titanium-based materials, of which silicon-based materials and titanium-based materials have a small number of applications in the market. The current negative electrode materials for lithium battery packs have developed from a single artificial graphite to natural graphite, mesophase carbon microspheres, artificial graphite, soft carbon/hard carbon, amorphous carbon, lithium titanate, silicon carbon alloy and other negative electrodes. The coexistence of materials. 3. Market situation of anode materials for lithium battery packs From a technical point of view, the future of anode materials for lithium battery packs will show diversified characteristics. At this stage, graphite materials are the mainstream of anode materials, and graphene, lithium titanate, and silicon-carbon composite materials have good development prospects in the future. In 2016, China's output of anode materials was 122,500 tons, an increase of 68.27% year-on-year. The current growth rate is mainly due to: 1) The domestic power battery output increased by more than 200% year-on-year, which drove the demand for negative electrode materials; 2) Although the growth rate of China's digital market slowed down, it still increased slightly. 4. Advantages and disadvantages of silicon-carbon materials. Graphite anodes are the main anode materials and have been widely used. However, the capacity of graphite anode materials has reached 360mAh/g, which is close to the theoretical gram capacity of 372mAh/g, and I want to increase its space. It has been difficult to achieve. The chemical properties of silicon and carbon are similar. Silicon can be alloyed with lithium at room temperature to form Li15Si4 phase. The theoretical specific capacity is as high as 3572mA·h/g, which is much higher than the theoretical specific capacity of commercial graphite. It has very rich reserves of elements in the crust. Because of its low cost and environmental friendliness, silicon anode materials have always attracted the attention of researchers and are one of the most potential next-generation anode materials for lithium battery packs. However, since silicon is prone to volume expansion (~300%) during charging and discharging, this limits the commercial application of silicon anodes, and the price and cost are relatively high. The volume expansion of silicon will result in pulverization of particles, poor cycle performance, and poor contact between the active material and the conductive agent binder. 5. Market potential of silicon-carbon materials. The excellent electrochemical performance of silicon-carbon anodes has attracted many anode material manufacturers to invest in the development and production of silicon-carbon materials, including Guoxuan Hi-Tech, CATL, BAK Battery, BYD, Tianjin Li God and others have already begun to deploy related products. Silicon carbon anode has a very broad market space. The anode material technology is relatively mature, and its concentration is relatively high, and the transfer of production capacity from Japan to China is relatively obvious. At present, the anode material is mainly carbon material, which accounts for a relatively low cost of lithium battery packs, and has basically achieved full industrialization in China. From a regional perspective, China and Japan are the world's major production and sales countries, and power battery companies purchase negative electrodes mainly from Japanese companies. Silicon-carbon anode materials are the most promising anode materials for lithium battery packs in the future. It can be seen how large the market capacity of silicon-carbon anode materials is. 6. The silicon carbon material market will not explode on a large scale in the short term. On the supply side, because the price of silicon carbon anode is very high and the requirements for the production environment are also very high, it is difficult to release production capacity in the short term. On the application side, the electrolyte and cathode material system matching the silicon carbon anode is not mature yet, and the large-scale application of silicon carbon anode is also difficult. So far, only a small number of 18650 products of cylindrical manufacturers have been mass-produced and applied. It is expected that after 2020, as the domestic square lithium battery packs gradually begin to use silicon carbon anodes, the market demand for silicon carbon anodes will grow rapidly. Summary: Technological innovation is gratifying, but looking for new lithium battery pack raw materials with higher cost-effectiveness, larger reserves, and more pricing power is the root cause of improving the ability of industry terminals to reduce costs and increase efficiency.