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CN-122028545-A - Back contact battery, battery assembly and photovoltaic system

CN122028545ACN 122028545 ACN122028545 ACN 122028545ACN-122028545-A

Abstract

The application relates to the technical field of solar cells and provides a back contact cell, a cell assembly and a photovoltaic system, wherein in the back contact cell, the doping concentration of doping elements at the middle position of a separation part is 1E13/cm 3 -5E16/cm 3 , the height of a first surface of the separation part is H1, the height of a second surface of a p-type doping part is H2, the height of a third surface of an n-type doping part is H3, H1 is H2, H2 is H3, the thickness of the separation part is D1, the thickness of the p-type doping part is D2, and the thickness of the n-type doping part is D3, D1 is D2, and D2 is D3. Therefore, through the optimal design of the doping concentration of the isolation part, the heights of the first surface of the isolation part, the second surface of the p-type doping part and the third surface of the n-type doping part and the optimal design of the thicknesses of the isolation part, the p-type doping part and the n-type doping part, the composite loss can be reduced, the field passivation effect can be improved, the series resistance loss can be reduced, and the conversion efficiency of the back contact battery can be improved.

Inventors

  • ZHANG SHENGLI
  • JIANG SHENG
  • LI ZHONGYU
  • ZOU CAN
  • LIU RUIMIN
  • WANG YONGQIAN

Assignees

  • 浙江爱旭太阳能科技有限公司

Dates

Publication Date
20260512
Application Date
20260416

Claims (18)

  1. 1. A back contact battery, comprising: a silicon substrate having opposite front and back sides; a first dielectric layer laminated on the back surface, and The doped layer is stacked on the first dielectric layer and comprises p-type doped parts and n-type doped parts which are arranged at intervals, and isolation parts which are positioned between the p-type doped parts and the n-type doped parts, wherein two sides of the isolation parts are respectively contacted with the p-type doped parts and the n-type doped parts; The p-type doped part is doped with a third main group element, the n-type doped part is doped with a fifth main group element, the isolation part is doped with at least one of the third main group element and the fifth main group element, and the doping concentration of the doped element at the middle position of the isolation part is 1E13/cm 3 -5E16/cm 3 ; The isolation part comprises a first surface facing away from the silicon substrate, the p-type doped part comprises a second surface facing away from the silicon substrate, the n-type doped part comprises a third surface facing away from the silicon substrate, the height of the first surface is H1, the height of the second surface is H2, and the height of the third surface is H3, H1> H2, and H2> H3; The thickness of the isolation part is D1, the thickness of the p-type doped part is D2, and the thickness of the n-type doped part is D3, D1> D2, and D2> D3.
  2. 2. The back contact cell of claim 1, wherein in the back contact cell 10nm +.h1-H2, 20nm +.h2-H3.
  3. 3. The back contact cell of claim 2, wherein in the back contact cell 10nm +.h1-h2 +.80 nm,20nm +.h2-h3 +.120 nm.
  4. 4. The back contact cell of claim 1, wherein 20nm +.h1-H3 in the back contact cell.
  5. 5. The back contact cell of claim 4, wherein in the back contact cell 20nm +.h1-h3 +.160 nm.
  6. 6. The back contact battery of claim 1, wherein in the back contact battery, H1-H2< H2-H3.
  7. 7. The back contact cell of claim 1, wherein in the back contact cell, 100nm +.d1 +.500nm, 80nm +.d2 +.450nm, 30nm +.d3 +.420 nm.
  8. 8. The back contact battery of claim 1, wherein in the back contact battery, 0.75 +.d2/d1 +. 0.96,0.3 +.d3/d1 +.0.8.
  9. 9. The back contact battery of claim 1, wherein 0.2 +.d3/d2 +.0.85 in the back contact battery.
  10. 10. The back contact cell of claim 1, wherein in the back contact cell 10nm +.d1-d2 +.80 nm.
  11. 11. The back contact cell of claim 1, wherein 20nm +.d2-d3 +.120 nm in the back contact cell.
  12. 12. The back contact cell of claim 1, wherein 20nm +.d1-d3 +.160 nm in the back contact cell.
  13. 13. The back contact battery of claim 1, wherein the doping concentration of the third main group element in the p-type doping is 1E19/cm 3 -1.6E20/cm 3 and the doping concentration of the fifth main group element in the n-type doping is 6E19/cm 3 -1.2E21/cm 3 .
  14. 14. The back contact battery of claim 1, wherein the sheet resistance of the p-type doped portion is greater than the sheet resistance of the n-type doped portion.
  15. 15. The back contact battery of claim 11, wherein the sheet resistance of the p-type doped portion is 1.2-3 times the sheet resistance of the n-type doped portion.
  16. 16. The back contact battery according to claim 1, wherein in the back contact battery, a ratio between a doping concentration of a fifth main group element in the n-type doped portion and a doping concentration of a third main group element in the p-type doped portion is S; wherein, S satisfies the following relation, S=K (D2-D3)/20 , and the value range of K is 1.04-2.24.
  17. 17. A battery assembly comprising a plurality of back contact cells according to any one of claims 1-16.
  18. 18. A photovoltaic system comprising the cell assembly of claim 17.

Description

Back contact battery, battery assembly and photovoltaic system Technical Field The application relates to the technical field of solar cells, in particular to a back contact cell, a cell assembly and a photovoltaic system. Background The back contact solar cell enables the light receiving surface to completely avoid shielding of the metal electrode by integrating the emitter electrode and the base electrode contact electrode on the back of the cell, thereby remarkably improving light capturing capacity and short circuit current output. In the back contact battery of the related art, in order to realize electrical isolation between the p-type region and the n-type region, a process scheme of etching a deep trench on a silicon substrate is generally adopted, in such a case, during the process of forming the deep trench, the side surface of the p-type region and the side surface of the n-type region are directly exposed at the trench, and the exposure can lead to the formation of a large number of surface defect states at the junctions (i.e., the side surfaces of the p-type region and the n-type region) between the p-type region and the n-type region and the deep trench, thereby causing larger recombination loss, reducing the collection efficiency of carriers and severely restricting the improvement of the photoelectric conversion efficiency of the back contact battery. Disclosure of Invention The application provides a back contact battery, a battery assembly and a photovoltaic system. The application is realized in such a way that the back contact battery of the embodiment of the application comprises: a silicon substrate having opposite front and back sides; a first dielectric layer laminated on the back surface, and The doped layer is stacked on the first dielectric layer and comprises p-type doped parts and n-type doped parts which are arranged at intervals, and isolation parts which are positioned between the p-type doped parts and the n-type doped parts, wherein two sides of the isolation parts are respectively contacted with the p-type doped parts and the n-type doped parts; The p-type doped part is doped with a third main group element, the n-type doped part is doped with a fifth main group element, the isolation part is doped with at least one of the third main group element and the fifth main group element, and the doping concentration of the doped element at the middle position of the isolation part is 1E13/cm 3-5E16/cm3; The isolation part comprises a first surface facing away from the silicon substrate, the p-type doped part comprises a second surface facing away from the silicon substrate, the n-type doped part comprises a third surface facing away from the silicon substrate, the height of the first surface is H1, the height of the second surface is H2, and the height of the third surface is H3, H1> H2, and H2> H3; The thickness of the isolation part is D1, the thickness of the p-type doped part is D2, and the thickness of the n-type doped part is D3, D1> D2, and D2> D3. In some embodiments, in the back contact cell, 10 nm≤H2-H2, 20 nm≤H2-H3. In some embodiments, in the back contact cell, 10 nm≤H2-H2≤80 nm,20 nm≤H2-H2 3≤120 nm. In some embodiments, 20 nm≤H2-H3 in the back contact cell. In some embodiments, 20 nm≤H2-H2 3≤160 nm in the back contact cell. In some embodiments, in the back contact cell, H1-H2< H2-H3. In some embodiments, in the back contact cell, 100 nm≤D1≤500 nm,80 nm≤D2≤450 nm,30 nm≤D3≤420 nm. In some embodiments, in the back contact cell, D2/D1 is more than or equal to 0.75 and less than or equal to 0.96,0.3, D3/D1 is more than or equal to 0.8. In some embodiments, 0.2≤D3/D2≤0.85 in the back contact cell. In some embodiments, in the back contact cell, 10 nm≤D1-D2≤80 nm. In some embodiments, 20 nm≤D2-D3≤120 nm in the back contact cell. In some embodiments, 20 nm≤D1-D3≤160 nm in the back contact cell. In some embodiments, the doping concentration of the third main group element in the p-type doping is 1E19/cm 3-1.6E20/cm3 and the doping concentration of the fifth main group element in the n-type doping is 6E19/cm 3-1.2E21/cm3. In some embodiments, the sheet resistance of the p-type doping is greater than the sheet resistance of the n-type doping. In some embodiments, the sheet resistance of the p-type doping is 1.2-3 times the sheet resistance of the n-type doping. In some embodiments, in the back contact cell, a ratio between a doping concentration of a fifth main group element in the n-type doping portion and a doping concentration of a third main group element in the p-type doping portion is S; wherein, S satisfies the following relation, S=K (D2-D3)/20, and the value range of K is 1.04-2.24. The application also provides a battery assembly comprising a plurality of back contact batteries as described in any one of the above. The application also provides a photovoltaic system, which comprises the battery assembly. In the back contact battery, the battery component and the photov