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CN-113345970-B - P-type back contact crystalline silicon solar cell, preparation method and cell assembly

CN113345970BCN 113345970 BCN113345970 BCN 113345970BCN-113345970-B

Abstract

The invention is applicable to the technical field of solar cell processing, and provides a P-type back contact type crystalline silicon solar cell, a preparation method and a cell assembly, wherein the P-type back contact type crystalline silicon solar cell comprises a P-type silicon wafer, and a passivation anti-reflection layer is arranged on the front surface of the P-type silicon wafer; the back of the silicon wafer substrate is provided with a P+ doped region, an N+ doped region, a back passivation layer, a positive electrode and a negative electrode, the P+ doped region and the N+ doped region are alternately distributed at intervals, the N+ doped region comprises a tunneling oxide layer arranged on the back of the P-type silicon wafer and N+ doped polysilicon arranged on the tunneling oxide layer, a textured structure is arranged at the position, corresponding to the negative electrode, of the back of the P-type silicon wafer, and a rough texture structure which forms ohmic contact with the N+ doped polysilicon is arranged at the position, corresponding to the textured structure, of the negative electrode. The P-type back contact type crystalline silicon solar cell provided by the invention can effectively improve ohmic contact between a negative electrode and N+ doped polycrystalline silicon, improves the cell efficiency, and is simple in implementation mode and low in implementation cost.

Inventors

  • SHAO JIAJUN
  • CHEN GANG

Assignees

  • 浙江爱旭太阳能科技有限公司
  • 珠海富山爱旭太阳能科技有限公司
  • 广东爱旭科技有限公司
  • 天津爱旭太阳能科技有限公司

Dates

Publication Date
20260505
Application Date
20210604

Claims (12)

  1. 1. The P-type back contact type crystalline silicon solar cell is characterized by comprising a P-type silicon wafer, wherein the front surface of the P-type silicon wafer is provided with a passivation anti-reflection layer; The back of the P-type silicon wafer is provided with a P+ doped region, an N+ doped region, a back passivation layer, a positive electrode and a negative electrode, wherein the P+ doped region and the N+ doped region are alternately distributed at intervals, and the back passivation layer covers the P+ doped region and the N+ doped region; The N+ doped region comprises a tunneling oxide layer arranged on the back surface of the P-type silicon wafer and N+ doped polysilicon arranged on the tunneling oxide layer, wherein the positive electrode and the P+ doped region form ohmic contact, the negative electrode and the N+ doped polysilicon form ohmic contact, a textured structure is arranged at the position, corresponding to the negative electrode, of the back surface of the P-type silicon wafer, a rough texture structure which forms ohmic contact with the N+ doped polysilicon is arranged at the position, corresponding to the textured structure, of the negative electrode, the width of the textured structure is 80-200um, and the square resistance of the N+ doped polysilicon is 50-200 ohm/sqr; the back of the P-type silicon wafer is provided with grooves corresponding to the P+ doped regions in number, each P+ doped region is correspondingly arranged at the bottom of one groove, the bottom of the groove is provided with a suede, the positive electrode is arranged on the suede, and the passivation layer on the back covers the suede.
  2. 2. The P-type back contact type crystalline silicon solar cell according to claim 1, wherein the width of the groove is 300-600um, the depth of the groove is 0.3-10um, and the distance between two adjacent grooves is 20-500um.
  3. 3. The P-type back contact crystalline silicon solar cell of claim 1, wherein the tunnel oxide layer has a thickness of 1-5nm.
  4. 4. The P-type back contact crystalline silicon solar cell of claim 1, wherein the passivation anti-reflection layer and the back passivation layer are each one or more combinations of aluminum oxide film, silicon nitride film, silicon oxynitride film.
  5. 5. The preparation method of the P-type back contact type crystalline silicon solar cell is characterized by comprising the following steps of: polishing, namely selecting a P-type silicon wafer and polishing the P-type silicon wafer; The first texturing is carried out, namely, the texturing is carried out on the back surface of the P-type silicon wafer at the position corresponding to the position where the negative electrode is prepared to form a textured structure, and the width of the textured structure is 80-200um; preparing a tunneling oxide layer, namely preparing the tunneling oxide layer on the back surface of the P-type silicon wafer; preparing N+ doped polysilicon, namely preparing N+ doped polysilicon on the back surface of the P-type silicon wafer, wherein the sheet resistance of the N+ doped polysilicon is 50-200 omega/sqr; the second texturing is carried out, wherein the front surface of the P-type silicon wafer is textured to form a textured surface, and the back surface of the P-type silicon wafer is textured to form a textured surface at the position corresponding to the positive electrode preparation position; preparing a passivation antireflection layer and a back passivation layer, namely preparing the passivation antireflection layer on the front side of the P-type silicon wafer and preparing the back passivation layer on the back side of the P-type silicon wafer; laser grooving, namely performing laser grooving on the back surface of the P-type silicon wafer at a position corresponding to the positive electrode preparation position so as to expose the P-type silicon wafer; Printing and sintering positive and negative electrodes, namely printing a negative electrode at a first texturing position of the back surface of the P-type silicon wafer by using silver paste, printing a positive electrode at a laser grooving position of the back surface of the P-type silicon wafer by using aluminum paste, and sintering and drying to form a P+ doped region between the positive electrode and the P-type silicon wafer, wherein the negative electrode forms a rough texture structure in ohmic contact with the N+ doped polysilicon.
  6. 6. The method for manufacturing a P-type back contact type crystalline silicon solar cell according to claim 5, wherein the polishing of the P-type silicon wafer comprises: and polishing the P-type silicon wafer by using an alkali solution with the concentration of 1.5-15%, wherein the reflectivity of the polished P-type silicon wafer is controlled to be 38-45%.
  7. 7. The method for manufacturing a P-type back contact crystalline silicon solar cell according to claim 5, wherein the step of first texturing comprises: Preparing a mask on the back of the P-type silicon wafer; performing laser ablation etching mask at the position of the back of the P-type silicon wafer corresponding to the preparation of the negative electrode so as to expose the P-type silicon wafer; And texturing in a laser ablation area on the back surface of the P-type silicon wafer to form a textured structure, and removing a mask of a non-laser ablation area through pickling.
  8. 8. The method for manufacturing a P-type back contact crystalline silicon solar cell according to claim 5, wherein the thickness of the tunneling oxide layer is controlled to be 1-5nm.
  9. 9. The method for manufacturing a P-type back contact type crystalline silicon solar cell according to claim 5, wherein the thickness of the n+ doped polysilicon is controlled to be 50-350nm.
  10. 10. The method for manufacturing a P-type back contact crystalline silicon solar cell according to claim 5, wherein the step of second texturing specifically comprises: Preparing a mask on the back of the P-type silicon wafer; Performing laser local ablation etching mask on the position, corresponding to the positive electrode preparation, of the back surface of the P-type silicon wafer so as to expose the P-type silicon wafer; and texturing is carried out on the laser ablation areas on the front surface of the P-type silicon wafer and the back surface of the P-type silicon wafer to form a textured surface, and a mask of the non-laser ablation area is removed through pickling.
  11. 11. The method for preparing a P-type back contact type crystalline silicon solar cell according to claim 5, wherein the step of preparing n+ doped polysilicon comprises: Depositing N+ doped amorphous silicon on the back of the P-type silicon wafer, and crystallizing the N+ doped amorphous silicon into N+ doped polysilicon at high temperature, or, Depositing intrinsic amorphous silicon on the back of the P-type silicon wafer, performing phosphorus diffusion on the intrinsic amorphous silicon to obtain N+ doped amorphous silicon, and crystallizing the N+ doped amorphous silicon into N+ doped polycrystalline silicon at high temperature.
  12. 12. A solar cell module comprising a P-type back contact crystalline silicon solar cell as claimed in any one of claims 1 to 4.

Description

P-type back contact crystalline silicon solar cell, preparation method and cell assembly Technical Field The invention relates to the technical field of solar cell processing, in particular to a P-type back contact crystalline silicon solar cell, a preparation method and a cell assembly. Background Currently, with the gradual depletion of fossil energy, solar cells are increasingly used as new energy alternatives. A solar cell is a device that converts solar light energy into electrical energy. The solar cell generates carriers by utilizing the photovoltaic principle, and then the carriers are led out by using the electrodes, so that the electric energy can be effectively utilized. The P-type back contact type crystalline silicon solar cell generally comprises a P-type silicon wafer, wherein a passivation anti-reflection layer is arranged on the front surface of the P-type silicon wafer, a tunneling oxide layer, N+ doped polycrystalline silicon arranged on the tunneling oxide layer, P+ doped regions which are arranged on the back surface of the P-type silicon wafer and are alternately distributed with the N+ doped polycrystalline silicon, and a back passivation layer covering the N+ doped polycrystalline silicon, the N+ doped polycrystalline silicon is provided with a negative electrode, and the P+ doped region is provided with a positive electrode. In the prior art, since the P-type back contact type crystalline silicon solar cell needs polishing treatment before the preparation of the tunneling oxide layer, the position of the back surface of the P-type silicon wafer corresponding to the negative electrode is contacted with the tunneling oxide layer through the polishing surface, so that the N+ doped polysilicon prepared on the tunneling oxide layer and the back passivation layer prepared on the N+ doped polysilicon are both planar structures, ohmic contact is realized between the printed and sintered negative electrode and the N+ doped polysilicon through planar contact, and the ohmic contact effect between the negative electrode and the N+ doped polysilicon is poor, thereby influencing the cell efficiency. Disclosure of Invention The invention provides a P-type back contact type crystalline silicon solar cell, and aims to solve the problem that in the prior art, ohmic contact effect between a negative electrode of the P-type back contact type crystalline silicon solar cell and N+ doped polycrystalline silicon is poor, so that cell efficiency is affected. The invention is realized in such a way, and provides a P-type back contact type crystalline silicon solar cell, which comprises a P-type silicon wafer, wherein the front surface of the P-type silicon wafer is provided with a passivation anti-reflection layer; The back of the P-type silicon wafer is provided with a P+ doped region, an N+ doped region, a back passivation layer, a positive electrode and a negative electrode, wherein the P+ doped region and the N+ doped region are alternately distributed at intervals, and the back passivation layer covers the P+ doped region and the N+ doped region; The N+ doped region comprises a tunneling oxide layer arranged on the back surface of the P-type silicon wafer and N+ doped polysilicon arranged on the tunneling oxide layer, the positive electrode and the P+ doped region form ohmic contact, the negative electrode and the N+ doped polysilicon form ohmic contact, a textured structure is arranged at the position, corresponding to the negative electrode, of the back surface of the P-type silicon wafer, and a rough texture structure which forms ohmic contact with the N+ doped polysilicon is arranged at the position, corresponding to the textured structure, of the negative electrode. Preferably, the width of the suede structure is 80-200um. Preferably, the sheet resistance of the N+ doped polysilicon is 50-200 ohm/sqr. Preferably, grooves corresponding to the number of the p+ doped regions are formed in the back surface of the P-type silicon wafer, and each p+ doped region is correspondingly arranged at the bottom of one groove. Preferably, a suede is arranged at the bottom of the groove, the positive electrode is arranged on the suede, and the back passivation layer covers the suede. Preferably, the width of the groove is 300-600um, the depth of the groove is 0.3-10um, and the distance between two adjacent grooves is 20-500um. Preferably, the thickness of the tunneling oxide layer is 1-5nm. Preferably, the passivation anti-reflection layer and the back passivation layer are respectively one or more of an aluminum oxide film, a silicon nitride film and a silicon oxynitride film. The invention also provides a preparation method of the P-type back contact crystalline silicon solar cell, which comprises the following steps: polishing, namely selecting a P-type silicon wafer and polishing the P-type silicon wafer; The first texturing is carried out, namely, texturing is carried out on the back surface of the P-type sili