Interdigital PN-junction battery structure of IBC battery and fabrication method of interdigital PN-junction battery structure

Abstract

The invention discloses an interdigital PN-junction battery structure of an IBC battery and a fabrication method of the interdigital PN-junction battery structure. The battery structure sequentially comprises a silicon nitride anti-reflection film layer, a first silicon nitride thin film layer, an N-type single-crystal wafer substrate, an interdigital P region and N region layer, a second siliconnitride thin film layer and a Al2O3 thin film layer. The fabrication method comprises the steps of doping a back surface of the N-type single-crystal wafer substrate by a mode of printing and picoseconds laser doping, and performing phosphorus doping on a region which is not printed; growing a silicon nitride thin film by a mode of oxidization; depositing an intrinsic amorphous silicon layer; depositing the silicon nitride anti-reflection thin film; depositing the Al2O3 thin film; and opening a hole, and printing aluminum paste on the back surface to form a metal electrode. By the battery structure and the preparation method, the manufacturing process is reduced, and the manufacturing cost of the IBC battery is reduced; and moreover, the fabrication of high-quality PN on the back surface of the IBC battery can be achieved, and great output of an internal current of the IBC battery is achieved.

Description

technical field [0001] The invention relates to a battery structure of an interdigitated PN junction of an IBC battery and a preparation method thereof, belonging to the technical field of solar batteries. Background technique [0002] In recent years, driven by the national photovoltaic policy, the installed capacity of photovoltaic power generation has grown rapidly, and photovoltaic technology has developed rapidly. More and more photovoltaic enterprises have increased investment in research and development of IBC battery technology. They are all vigorously developing technology, and IBC has become one of the focuses of high-efficiency battery technology development due to its excellent battery technology. It can be seen that the advantages of N-type battery technology in the global photovoltaic market are becoming more and more obvious, especially the urgent need for photovoltaic power grid parity. Continuous technological innovation to minimize the cost of photovoltaic ...

AI Technical Summary

Problems solved by technology

[0003] At present, the preparation process flow of IBC batteries is relatively large, the equipment is expensive, and the battery manufacturing cost is high

Since the front of the IBC battery is not covered by grid lines, the short-circuit current of the battery is about 7% higher than that of the conventional battery. Under the condition of AM1.5G, the short-circuit current density generally exceeds 41mA / cm 2 , and the emitter and back surface fields of the battery are on the back, the front surface can be designed more flexibly to minimize optical loss and surface recombination, and improve the open circuit voltage and fill factor of the battery; at the same time, the open circuit voltage of the battery exceeds 680mV, and the short circuit current 41.5mA / cm 2 , the battery temperature coefficient is low, no LID, PID attenuation is less than 1%, no hot spot phenomenon, excellent reliability; IBC shows good electrical performance and reliability performance, but in industrial production, it still faces high production cost, which is different from the existing Conventional PERC production lines have poor compatibility and high equipment investment costs. At the same time, the quality of the PN junction on the back of the IBC battery is also the key to IBC battery technology

At present, when the tubular boron is diffused to form the P region, high temperature is required, and the uniformity of the square resistance is relatively poor, which is not conducive to the effective collection of current.

The traditional technical route is liquid boron diffusion and photolithography technology, but high temperature process is required, and the uniformity is poor; in addition, the P region and N region with good uniformity and precise controllable junction depth can be obtained by using ion implantation technology, which has great advantages. Good development prospects, but the cost is relatively high, and it has not yet been industrialized

[0004] Nowadays, tubular high-temperature boron diffusion and phosphorus diffusion are commonly used to prepare the P and N regions on the back of the IBC battery. In this process, multiple masks and photolithography techniques are required. The process is relatively complicated and the square resistance uniformity is relatively poor. , the quality of the PN junction is average; in addition, some companies use ion implantation technology to perform selective ion implantation through masks to achieve patterned phosphorus doping and boron doping respectively. However, the current ion implantation boron technology is difficult and mass production is stable Poor, and expensive ion implantation equipment, gas B required for boron doping 2 h 6 Toxic, the cost of IBC batteries is high

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