Artificial graphite | Graphite in the photovoltaic industry

As an industrial production raw material, man-made has many unique advantages, so graphite materials in industrial production has a wide range of applications, with the continuous development of the solar photovoltaic industry, the raw and auxiliary materials in the production process of solar photovoltaic materials are also increasing sharply, has been more widely used. The application of multiple processes in the entire photovoltaic industry, from silicon ore smelting to polysilicon production, to polysilicon ingots and straight-pull single crystals, is inseparable from the use of artificial graphite.

Special properties of artificial graphite

Six basic properties is illustrated one by one.

(1) Thermal shock resistance: artificial graphite can withstand violent changes in temperature without damage when used at room temperature, and when the temperature is abrupt, the volume changes little and will not produce fission.

(2) Chemical stability: It has good chemical stability at room temperature, and can resist acid, alkali and organic solvent corrosion.

(3) Lubricity: Its lubricating performance depends on the size of the artificial graphite scale, the larger the scale, the better the friction lubrication performance.

(4) Plasticity: graphite has good toughness and can be crushed into thin sheets by mechanical process.

(5) Excellent electrical and thermal conductivity: The electrical conductivity of artificial graphite is a hundred times higher than that of ordinary non-metals, and the thermal conductivity exceeds that of steel, iron, lead and other metal materials.

(6) High temperature resistance: even if artificial graphite is burned by ultra-high temperature arc, the weight loss is very small, and the coefficient of thermal expansion is also very small.

Application of artificial graphite in photovoltaics

Artificial graphite is different from most other materials, its tensile, flexural and compressive strength will increase with the increase of temperature. It is usually applied to photovoltaics. as follows:

(1) Smelting silicon: solar photovoltaic cell production starts from silicon metal smelting, and a key equipment used in silicon metal smelting is a silicon metal smelting furnace; In the silicon metal smelting furnace, the electrode is the heart, which is an important part of the conductive system, and the current is entered into the furnace through the electrode to generate an arc, which is an important link in chemical silicon smelting. The electrode made of artificial graphite has low ash content, good electrical conductivity, heat resistance and corrosion resistance, and is the best choice for chemical silicon smelting.

(2) Production of polysilicon: more than 85% of solar-grade polysilicon products on the market are produced by relying on improved brand technology, and artificial graphite is widely used in multiple processes with its excellent characteristics in the production process of improved technology; For example, a large number of graphite consumables are used in the reduction furnace of polysilicon vapor deposition, and artificial graphite materials are also used in the thermal hydrogenation process of treating the by-product silicon tetrachloride.

The development of artificial graphite in the photovoltaic industry

(1) The graphite materials required by the solar photovoltaic industry are ultra-fine, high-purity and other characteristics, and stripping purification is conducive to protecting the large scales of graphite, but the loss of corrosion-resistant grinding medium directly affects the effect of acid purification. The crushing and purification process should be used as the whole process design, and high-purity ultrafine graphite powder should be artificially produced.

(2) At present, graphite materials in the photovoltaic industry can withstand high temperature, but the service life is not long enough, so that there are more consumables in production; Therefore, it is necessary to further develop new artificial graphite materials to maintain the characteristics of high temperature resistance and oxidation resistance, and can also enhance mechanical strength and extend service life. This can reduce the amount of graphite consumables in solar photovoltaic production and greatly reduce the cost of solar photovoltaic production.

With the rapid development of the photovoltaic industry, the amount of high-purity carbon graphite, an important raw and auxiliary material in production, has risen significantly, and many raw and auxiliary materials in the photovoltaic industry need to use artificial graphite with stable performance and less interference factors as processing raw materials. Franli’s factory is also gradually upgrading its technology to produce artificial graphite to produce better quality graphite materials. It is convenient to develop photovoltaic technology and technology, which can greatly improve the overall country’s trade and economic level.