The new energy automobile industry has not only maintained the characteristics of the long chain of the traditional automobile industry, but also added some important industrial links, such as battery, motor and electric control. The change of external environment is promoting the new round of industrial transformation of the automotive industry. New energy vehicle is an important direction of upgrading and transformation of the automotive industry. The resources, production mode, matching relationship and industrial layout of the new energy vehicle are constantly changing.

Upstream raw material

Mineral resources represented by lithium, cobalt, nickel, graphite and rare earth have important applications in the field of new energy vehicles, especially battery grade lithium carbonate is one of the key raw materials of power battery. Magnesium aluminum and its alloys are important materials for automobile lightening.
Automotive parts, automotive materials
Power battery

cathode material

Cathode materials determine the main properties of lithium ion batteries, such as energy density, cycle stability, safety, and so on. Cathode materials include lithium cobalt, lithium manganate, lithium iron phosphate and three yuan materials. At present, lithium battery positive pole follows the development trend from two yuan material to three yuan material. The positive material of Panasonic NRC18650B is three yuan material of nickel, cobalt and aluminum, commonly known as NCA. By introducing Ni content, the capacity of the material can be increased, while Panasonic NRC18650B increases the Ni content (mole fraction 80%), so that the battery increases from original 2.9Ah to 3.3Ah, and the energy density is greatly improved. At the same time, it has benefited from the synergistic effect of three yuan. The NCA positive material combines the advantages of LiNiO2 and LiCoO2, which is superior to the use of a single material. Moreover, the material has less cobalt and low cost.

The change trend of lithium anode: silicon anode

The biggest thing about the Si based negative material is the high theoretical energy density (4200mAh/g), far higher than the graphite. This is also in line with the demand for batteries for new energy vehicles. From the present trend, the future direction of the negative electrode is first to silicon and graphite, and the graphite of low energy density will be completely replaced by pure silicon / lithium metal.
The biggest shortcoming of silicon based anode materials is the expansion problem. After charging, it is easy to expand and fragment, and cannot recover, resulting in the final powdering of materials, which greatly reduces the battery life. In the charge and discharge process, there will be 300% expansion, while under the same conditions, graphite is only 7%. At present, the silicon content of the carbon silicon composite material developed by Matsushita has reached 10%. It can be seen that with the improvement of technology level, there is still much room for development.

Anode material

Cathode of lithium ion battery is composed of anode active material of carbon material or non carbon material, binder and additive mixture made of paste glue evenly on both sides of the copper foil, dried, rolled into. The negative materials are mainly divided into carbon materials (Shi Molei), metal oxide materials and alloy materials. Since the outbreak of power battery market, compared with other materials, the price of anode materials is relatively stable, and the technology route is mainly graphite. At present, the main negative materials are natural graphite and artificial graphite, and their performance has their own advantages and disadvantages, and the application field is different.

The diaphragm

The main function of the diaphragm is to ensure the free circulation of lithium ion in the case of the separation of positive and negative poles. It is one of the most important parts of the security of the battery. The diaphragm can be infiltrated in the electrolyte, and there is a large number of micropores allowed to pass through the lithium ion on the surface. Micropore density, material selection, thickness and so on will affect the speed of lithium ion through the diaphragm and affect the performance of the battery. It is estimated that the consumption of the diaphragm in the lithium battery is approximately 20m2/kWh.
The future of the diaphragm is more promising: coating diaphragm
Coated diaphragm is the coating of PVDF and other adhesive or ceramic alumina on the base film. The function of coating the diaphragm is: 1, improve the heat shrinkability of the diaphragm, prevent the contraction of the diaphragm from causing large area short circuit; 2, the low thermal conductivity of the coating material prevents the expansion of some thermal runaway points in the battery to form the overall control.

electrolyte

Electrolyte, as a carrier of lithium ion flow in lithium ion batteries, plays an important role in the operation and safety of lithium batteries. According to the calculation, in the cost composition of the electrolyte, the solvent is about 30%, the additive is about 10%, the most important component of the solute is about 60%. The solute in the market is mainly six fluoro lithium phosphate (LiPF6), while the Panasonic NCR18650 battery also uses six fluoro lithium phosphate as solute, and every kWh lithium battery needs six 0.15kg lithium phosphate.  Lithium six fluoro phosphate can also be prepared by lithium carbonate.
The future direction of the electrolyte is in the future: high voltage electrolyte
Improving battery energy density is one of the trends of lithium battery. There are mainly two ways to increase energy density. One is to increase the charging cut-off voltage of traditional cathode materials, such as raising the charging voltage of lithium cobalt oxide to 4.35V and 4.4V. But the way to raise the charging cut-off voltage is limited. Further increasing the voltage will lead to the collapse of lithium cobalt oxide and the instability of the properties. The other way is to develop new cathode materials with higher charge and discharge platform, such as lithium rich manganese base, nickel cobalt lithium and so on. After raising the voltage of cathode material, the matching of high voltage electrolyte and additives plays a key role in the high voltage performance of electrolyte, which has become the focus of research and development in recent years.

copper foil

According to the production process, the copper foil is divided into copper foil and electrolytic copper foil, and the calendering copper foil is generally used as a building decoration material. Due to the good conductivity of Po, soft texture, good ductility deformation, it is the preferred material for making lithium battery cathode collector. The function of a lithium ion battery collector is to assemble the current produced by the active substance of the battery so as to form a larger current output, so the collection of fluids should be due.