Depth study of the heterojunction photovoltaic industry battery project report

HIT the battery is based on crystalline silicon solar cell substrate, amorphous silicon thin film for passivation layer cell structure. 打( Heterojunction cell, Heterojunction with Intrinsic Thin layer) Is a p-type hydrogenated amorphous silicon and n-type hydrogenated amorphous silicon between n-type silicon substrate and add a layer of the doped ( Intrinsic) The cell structure of hydrogenated amorphous silicon thin film. Standard crystalline silicon solar cell is a kind of homogenous cells, namely the p-n junction is formed on the same kinds of semiconductor materials, and adopt different semiconductor heterojunction cell of PN junction material composition. Japanese sanyo invented in 1990 HIT the battery and apply for a registered trademark, so the heterojunction cell is also known as HJT ( 异质结技术) Or SHJ ( 硅异质结) 。

　　（ 1) High conversion efficiency: HIT the battery amorphous silicon layer are adopted to decrease the surface dangling bond density and heterojunction interface state density, high conversion efficiency. HIT the open circuit voltage of battery can reach more than 740 mv, the main reason is: 1) Crystal structure on the surface of the wafer has discontinuity, solar portal, dangling bond density lead to defect density is big, the amorphous silicon layer by reducing the surface density of hanging keys to achieve excellent interface passivation; 2) HIT the battery between monocrystalline silicon substrate and doped amorphous silicon thin film by inserting a thin layer of intrinsic amorphous silicon thin film, makes the heterogeneous barrier of the interface state density greatly reduced, so the open circuit voltage of battery is higher than conventional batteries, to achieve high conversion efficiency. At present, HIT the battery's lab efficiency over 26%, the average production efficiency of existing facilities in more than 23%, efficiency advantage is obvious.

　　（ 2) High rate of double: HIT the battery positive and negative for symmetric structure, and no metal back a block on the back into the light, so its natural have double capacity, and double rate more than 95%, in the extended range ( Sand, snow, water, etc. ) At the same time further enhance capacity.

　　（ 3) Matt: due to HIT the battery on the surface as the TCO, not on the surface of the battery, charge the polarization phenomenon TCO, so HIT the battery without PID, LePID phenomenon. Panasonic HIT components after 25 years output fell by 8%.

　　（ 4) Low temperature coefficient, solar energy, the high temperature environment capacity high: HIT the temperature of the battery good stability, and single crystal silicon cell - 0. Compared to 42% / ℃ temperature coefficient, solar portal, HIT the battery temperature coefficient can reach 0. 25% / ℃, making the battery even if under the condition of light up there is still a good output. In the noon of the day, HIT the battery power than the average 8-10% higher than that of crystal silicon solar cell, double bo HIT component of more than 20% capacity, and have a higher user added value.

　　（ 5) Weak light high response: theory study, the greater the resistance in parallel, the stronger the weak light response of the photovoltaic modules. Thin-film batteries because of parallel resistance is generally relatively large, so the weak light response is generally better. HIT belongs to thin-film batteries battery, so the weak light response performance better.

　　（ 6) Less process steps: HIT the battery production process only four steps, production has the advantage. At present, the mainstream of the PERC battery production need eight Ten working procedure, TOPCon need 11 - 12 working procedure, and HIT the battery process just 4. Theoretically, HIT less process steps, can greatly reduce the defective rate of the battery, and artificial, operations and other costs of production.

　　（ 7) Structure symmetry, wafer potential: HIT the battery perfect symmetry structure and low temperature process makes it very suitable for wafer. At present the PERC mainstream batteries used silicon thickness is 170 - 180μ M, solar equipment, HIT the battery used silicon layer has dropped to 160 & mu; M here, solar portal, and has a larger slice of the space.

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this paper statistics the September to today issued a total of 2. 85 gw pv power plant EPC and 1. 9 gw component bid opening information. Among them, the EPC project owner units is given priority to with soe/state, this also reflected from the side, in project bidding and parity, the state-owned enterprises have become the absolute main force. Specifically, CGNPC in development of 410 mw, 603 mw, guangzhou energy saving 220 mw, 345 mw, jin can group the people vote for 200 mw, 190 mw hubei energy group, huaneng power 180 mw