Back contact crystal silicon solar battery and manufacture process of back contact crystal silicon solar battery

Abstract

The invention discloses a back contact silicon solar battery, which comprises an N type monocrystalline silicon piece subjected to surface texturing, wherein a first N type heavy doping layer is arranged at the front side of the N type monocrystalline silicon piece, a silicon dioxide (SiO2) passivation layer and a reflection reduction film layer are sequentially arranged at the outer side of the first N type heavy doping layer, a second N type heavy doping layer and a P type heavy doping layer are arranged at the back side of the N type monocrystalline silicon piece in a mutual separating way, second SiO2 passivation layers are arranged at the outer side of the second N type heavy doping layer and the P type heavy doping layer, a heavy doping AZO film layer and silver slurry are sequentially arranged outside the second SiO2 passivation layer arranged at the second N type heavy doping layer part, and a heavy doping CuAlO2 film layer and silver aluminum slurry are sequentially arranged outside the second SiO2 passivation layer arranged at the P type heavy doping layer part. The invention also discloses a manufacture process of the back contact silicon solar battery. The back contact silicon solar battery and the manufacture method solve the problems that in the prior art, the conversion rate of the solar battery is low, and the back contact battery generally adopts laser punching, so the manufacture cost is high. Through the technical improvement, heavy doping is realized on the contact surface, the heavy-doping low-resistance transparent conductive oxide (TCO) materials are attached to the contact surface so as to form tunnel current, and in addition, a low-temperature slurry sintering method is adopted, the manufacture cost is reduced on the premise that the battery efficiency is ensured.

Description

technical field [0001] The invention relates to a back-contact crystalline silicon solar cell and a manufacturing process thereof, and belongs to the technical field of new solar cells. Background technique [0002] When sunlight hits a solar cell, the incident energy can be converted directly into electricity without mechanical rotation or polluting by-products. Solar cells are no longer the only treasures in the laboratory, and have been used for more than 50 years. What started out as providing power in space has now taken an increasing share of power generation on the ground. In recent years, the manufacturing technology of such batteries has been further improved. The production cost of solar cells will approach the level of thermal power generation, making a huge contribution to the world's energy demand. [0003] Among solar cells with various morphological structures, the back-contact crystalline silicon solar cell greatly reduces or even completely eliminates the...

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Problems solved by technology

[0004] In the design of back-contact cells, EWT (emitter warp through) and MWT (metal warp through) are the main design prototypes. The completely grid-free design on the front side can maximize the use of the light-receiving surface, and at the same time, all the positive and negative electrodes are moved to the back side. However, the back side has PN-type regional characteristics at the same time, and due to the existence of parasitic capacitance effects, conventional aluminum back field passivation or high-density positive charge passivation media cannot passivate both types at the same time. If thermal silicon oxide layer passivation design is adopted, In addition, due to the insulating properties of the oxide layer, it seriously affects the transport of carriers, greatly increases the series resistance and thus affects the efficiency of the battery. If the electrode is drawn out by laser dotting, it will undoubtedly increase the cost and the success rate cannot be guaranteed. , so the adoption rate of front completely gridless design is relatively low

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