Double-sided passivation contact P-type high-efficiency battery and preparation method thereof

Abstract

The invention discloses a preparation method of a double-sided passivation contact P-type high-efficiency battery. The preparation method comprises the following steps: S1, cleaning and texturing; S2,preparing frontal polysilicon; S3, preparing a mask; S4, etching; S5, diffusion; S6, cleaning; S7, annealing; S8, preparing a back polysilicon layer; S9, preparing a front SiNx antireflection layer;and S10. Printing. The invention also discloses the double-sided passivation contact P-type high-efficiency battery comprising P-type monocrystalline silicon. An N-type emitter is provided with a front ultra-thin silicon oxide layer far from the P-type monocrystalline silicon. A back ultra-thin silicon oxide layer is arranged on the back surface of the P-type monocrystalline silicon. The contact structure is passivated by using the tunnel oxide layer on the front and back surfaces of the battery so as to have great surface passivation effect. The silicon surface is passivated exactly under thefront metal gate line and the back aluminum back field so as to avoid direct contact between the metal and the silicon base, reduce the surface recombination and improve the conversion efficiency ofthe battery.

Description

technical field [0001] The invention relates to the technical field of battery passivation, in particular to a P-type high-efficiency battery with double-sided passivation contact and a preparation method thereof. Background technique [0002] The efficiency of crystalline silicon solar cells has risen rapidly in recent years, and the market's demand and expectations for high-efficiency cells have become higher and higher. Various new technologies and new structures have been adopted in the recent production of high-efficiency cells, such as heterojunction structures (HIT ) and tunnel oxide passivation contact (TOPCon) structures, etc. [0003] Among the various losses of solar cells, the loss of surface recombination accounts for a considerable proportion, and the recombination loss at the contact position between the metal and the silicon base is also difficult to ignore. [0004] In traditional PERC cells, the contact between the front gate line and the emitter is inevit...

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Problems solved by technology

[0004] In traditional PERC cells, the contact between the front gate line and the emitter is inevitable. Although the selective emitter (SE) technology can be used to reduce the surface recombination, the disadvantage is that the contact between the metal and the semiconductor still brings a lot of recombination, making the open circuit The voltage Voc and the short circuit current Isc are lost

[0005] Although the aluminum oxide coating on the back plays the role of passivating the surface, it is insulative in itself. It needs to be grooved by laser to make the aluminum back field on the back contact with silicon to collect carriers. The laser aperture ratio will affect the The degree of surface recombination, but the disadvantage is: it will lead to a low fill factor FF of the battery, which has certain limitations and limits the further improvement of PERC battery efficiency

[0006] The above methods of using selective emitter (SE) and laser slotting to reduce surface recombination are not good enough, and the defects are more obvious. Therefore, a new type of double-sided passivated contact battery is needed to reduce surface recombination.

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