Production technology of all-back electrode solar battery

Abstract

The invention discloses a production technology of an all-back electrode solar battery. The production technology comprises the steps of: (1) forming a back n+ diffusion layer area and a back p+ diffusion layer area, which are arranged in a finger-crossed manner, on the back surface of a n type silicon substrate, and forming a front surface n+ diffusion layer on the front surface of the n type silicon substrate; (2) carrying out annealing oxidation treatment on the n type silicon substrate to form an oxide layer; (3) deposing passivation layers on the front surface and the back surface of the n type silicon substrate, and deposing a reflection increasing film on the passivation layer on the front surface; and (4) printing conductive slurry on the back passivation layer, after sintering, forming contact electrodes respectively on the back p+ diffusion layer area and the back n+ diffusion layer area, and finishing the preparation of the all-back electrode solar battery. According to the invention, the single conductive slurry is printed on the passivation layers of the back p+ diffusion layer and the back n+ diffusion layer at the same time, the finger-crossed conductive electrodes low in contact resistance are formed on the p+ diffusion layer and the n+ diffusion layer after the sintering, the production technology of the IBC battery is simplified, and the production cost of the IBC battery is lowered.

Description

technical field [0001] The invention belongs to the field of solar cells, and in particular relates to a production process of an all-back-electrode solar cell. Background technique [0002] At present, the core of the third industrial revolution is the new energy revolution. Improving the efficiency of solar cells is the key to improving the utilization rate of solar energy. It represents the direction of advanced technology development and has an important impact on the structural adjustment and sustainable development of my country's photovoltaic industry. It is one of the major technologies that should be developed at present. [0003] Current crystalline silicon solar cells are fabricated from n-type or p-type silicon. As far as p-type crystalline silicon solar cells are concerned, due to the application of burn-through front-side silver paste and back-field aluminum paste, the process of silicon wafer cells is simple and the cost is low, so p-type crystalline silicon s...

AI Technical Summary

Problems solved by technology

However, in the preparation process of this solar cell, different conductive pastes need to be printed to form positive and negative electrodes, and the preparation process is relatively complicated.

[0005] Current crystalline silicon solar cells generally use fire-through silver paste technology, which can only form electrical contact on the p+ diffusion layer or n+ diffusion layer respectively, and it is difficult to form electrical contact on the p+ diffusion layer and n+ diffusion layer at the same time

The electrical contact on the p+ silicon diffusion layer uses burn-through conductive silver paste. At present, only DuPont and Helix have this kind of product in the world. It is generally called silver-aluminum paste, and aluminum powder needs to be added to the silver paste to reduce Contact resistance, but the addition of aluminum will increase the resistivity of the silver electrode after sintering, thereby increasing the series resistance of the solar cell, which is one of the technical bottlenecks to improve the efficiency of the cell

In addition, when silver-aluminum paste (conductive paste) can form electrical contact on p-type silicon, it is generally necessary to add more aluminum powder to the silver paste to reduce contact resistance, such as US patents US2013 / 0061919 and US2012 / 0031484, all describe the content ratio of aluminum powder in the silver paste in detail. The content of aluminum is at least greater than 1%. Due to the addition of more aluminum powder, the rapid diffusion of aluminum will damage the PN junction of the battery under high temperature sintering conditions. Especially the aluminum "spiking" produced by aluminum powder can reduce the open circuit voltage and parallel resistance of the solar cell, thereby reducing the conversion efficiency of the cell

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