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2022-08-03
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Analysis of automotive power batteries: which is better, silicon or graphite?

the hot pre-sale of Tesla Model 3 has once again focused people's attention on new energy vehicles. The significance for the lithium battery industry lies in the new power battery materials it uses. It is reported that the model 3 battery technology adopts silicon carbon negative electrode, the energy density will reach 300wh/kg, and the endurance mileage will be about 346 km. The increase in endurance mileage is due to the fact that the specific capacity of silicon material is much greater than that of graphite material, and the value of specific capacity directly reflects the fact that the power of battery per unit weight obtains mineral resources by holding shares

the theoretical gram capacity of graphite anode materials currently used in the market is 372mah/g, and the theoretical gram capacity of silicon carbon composites is about 4200mah/g, more than 10 times higher than that of graphite anode. The high capacity of silicon carbon anode material can fully meet the energy requirements of pure electric vehicle power battery, but the charging and discharging process of silicon-based lithium-ion battery produces huge material volume expansion effect, which makes it difficult to industrialization. The application of silicon carbon anode in model 3 battery technology is an important breakthrough in the industrialization of silicon carbon anode materials. It is reported that 10% silicon is added to the negative electrode material, and the energy density reaches 300wh/kg. With the advancement of technology, the silicon carbon negative electrode material is expected to further improve the capacity of lithium batteries. Inorganic silicon materials (silicon or silicon oxide is used as the negative electrode) have made significant contributions to the capacity of lithium batteries. Can another important member of silicon materials, silicone materials with excellent performance, also help the endurance of new energy vehicles

the main chain structure of organosilicon is Si-O bond, and the side chain is connected with other organic groups through silicon atoms. The bond energy of Si-O bond in organic silicon is much greater than that of C-C bond, so the thermal stability of organic silicon products is high, and the chemical bonds of molecules do not break or decompose under high temperature (or radiation). It can withstand high and low temperatures and can be used in a wide temperature range. At the same time, the main chain has enhanced its ability to deal with trade protectionism. There is no double bond and it is not easy to be decomposed by ultraviolet light and ozone. Due to its special composition and molecular structure, organosilicon integrates the functions of organic and inorganic substances, and has excellent high and low temperature resistance, weather resistance, electrical insulation, biocompatibility and so on. Organosilicon materials have been widely used in civil fields such as architecture, electronics, electricity, chemical industry, and even in aviation, cutting-edge technology, military technology and other fields. For example, it can be used in outer space with extreme conditions or Siberia or Sahara with dirt in extremely cold and hot oil tanks

temperature control

the carbonate in the electrolyte of lithium battery has a high melting point. Generally, when the temperature is lower than -20 ℃, the battery cannot work normally; When the temperature is too high, the battery diaphragm will melt, resulting in short circuit and battery fire. Only by maintaining the appropriate temperature can the battery achieve its best performance. The organosilicon materials customized by Dow Corning can effectively dissipate heat for the battery pack and cell, and improve the working temperature of the battery. At the same time, the dispensing liquid silicone can form a heat shield around the battery cell in the battery pack. When the environment is too cold or overheated, the battery can still operate efficiently

durability

during the daily use of new energy vehicles, moisture will cause the decomposition of lithium hexafluorophosphate in the battery to produce HF, and vibration may cause breakage of the pole ear and short circuit of the battery. These most common factors may affect the battery life. In this regard, Dow Corning has provided the silicone solution of "exclusive customization of battery pack" to protect the durability of the battery

insulation

another challenge faced by electric vehicle batteries lies in short circuit and overcurrent, and the insulation of silicone materials appropriately addresses this problem. The application of organic silicon in the battery can well protect the internal key electronic devices, cells and buses, so as to avoid the risk of power surge and battery fire and realize the weight reduction of the vehicle

as the power source of new energy vehicles, in addition to the positive material, negative material, diaphragm, electrolyte and other battery raw materials affecting its performance, the temperature change, vibration and moisture during the driving process of new energy vehicles will also change the battery performance, thereby affecting its endurance. Scientists have made a lot of exploration on the application of silicone in new energy vehicles. Dow Corning, as a leader in the silicone industry, has put forward a material solution to make new energy vehicles run further

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