US-12622087-B2 - Photovoltaic cell and manufacturing method for photovoltaic cell

US12622087B2US 12622087 B2US12622087 B2US 12622087B2US-12622087-B2

Abstract

The present disclosure relates to a photovoltaic cell and a method for manufacturing a photovoltaic cell. The photovoltaic cell includes a substrate including an emitter and a passivation layer stacked in sequence on one side of the substrate. The emitter includes a first plane and a second plane laminated along a thickness direction of the emitter, and part of the emitter between the second plane and the first plane is a first doped layer. Within a unit volume, a rate of change ΔC 1 between doping concentration of the second plane and doping concentration of the first plane satisfies: ΔC 1 ≤15%.

Inventors

Kun Yu
Changming Liu
Xinyu Zhang
Pengsong ZHAO
Dong Wang
Chao Zhou

Assignees

ZHEJIANG JINKO SOLAR CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20230725
Priority Date: 20220725

Claims (17)

1 . A photovoltaic cell, comprising: a substrate ( 1 ) comprising an emitter disposed in the substrate, and a passivation layer ( 11 ) stacked on a side of the emitter away from the substrate; wherein the emitter comprises a first plane ( 12 ) and a second plane ( 13 ) laminated along a thickness direction of the emitter, and part of the emitter between the second plane ( 13 ) and the first plane ( 12 ) is a first doped layer ( 15 ); and within a unit volume, a rate of change ΔC 1 between doping concentration of the second plane ( 13 ) and doping concentration of the first plane ( 12 ) satisfies: ΔC 1 ≤15%; wherein a third plane ( 14 ) is provided on a side of the second plane ( 13 ) away from the first plane ( 12 ), and part of the emitter between the third plane ( 14 ) and the second plane ( 13 ) is a second doped layer ( 16 ); and a rate of change ΔC 2 between doping concentration of the third plane ( 14 ) and the doping concentration of the second plane ( 13 ) satisfies: ΔC 2 ≤30%; wherein the rate of change ΔC 1 between doping concentration of the second plane ( 13 ) and doping concentration of the first plane ( 12 ) and the rate of change ΔC 2 between doping concentration of the third plane ( 14 ) and the doping concentration of the second plane ( 13 ) within a unit volume satisfy: ΔC 1 <ΔC 2 ; wherein a distance H1 between the second plane ( 13 ) and the first plane ( 12 ) satisfies: 0.3 μm≤H1≤0.35 μm; and a distance H2 between the third plane ( 14 ) and the first plane ( 12 ) satisfies: 0.5 μm≤H2≤0.7 μm.
2 . The photovoltaic cell according to claim 1 , wherein the substrate ( 1 ) is made of a silicon substrate material, and the silicon substrate material includes one or more of monocrystalline silicon, polycrystalline silicon, amorphous silicon, and microcrystalline silicon.
3 . The photovoltaic cell according to claim 1 , wherein a target element in the first doped layer ( 15 ) and the second doped layer ( 16 ) includes, but is not limited to, nitrogen, phosphorus, arsenic, boron, aluminum, gallium, indium, thallium.
4 . The photovoltaic cell according to claim 1 , wherein, within a unit volume, a rate of change ΔC 3 between doping concentration at a first position of the second plane ( 13 ).
5 . The photovoltaic cell according to claim 1 , wherein, doping concentration at a second position of the second plane ( 13 ) satisfies: ΔC 3 ≤25%.
6 . A method for manufacturing the photovoltaic cell according to claim 1 , comprising: doping a target element into the substrate ( 1 ) to form the emitter; and manufacturing the passivation layer on the first plane ( 12 ) of the emitter.
7 . The method according to claim 6 , wherein a manner of doping the target element includes, but not limited to, high-temperature doping, post-oxidation doping, laser doping, and the like, Laser doping is adopted in the present disclosure, so as to control a doping depth.
8 . The method according to claim 6 , wherein a third plane ( 14 ) is provided on a side of the second plane ( 13 ) away from the first plane ( 12 ), and said doping a target element into the substrate ( 1 ) comprises: coating the first plane ( 12 ) with a doping reagent ( 2 ) containing the target element; directing a first laser ( 3 ) through the doping reagent ( 2 ) into the second plane ( 13 ) to diffuse the target element to the first doped layer ( 15 ) and the second doped layer ( 16 ); and directing a second laser ( 4 ) through the doping reagent ( 2 ) into the third plane ( 14 ) to diffuse the target element of the second doped layer ( 16 ) to the first doped layer ( 15 ).
9 . The method according to claim 8 , wherein said directing a first laser ( 3 ) through the doping reagent ( 2 ) into the second plane ( 13 ) to diffuse the target element to the first doped layer ( 15 ) and the second doped layer ( 16 ) comprises: directing the first laser ( 3 ) through the doping reagent ( 2 ) and the first plane ( 12 ) into the second plane ( 13 ), and generating a high temperature; and driving the target element into the first doped layer ( 15 ) by the first laser ( 3 ) and further driving the target element to be diffused to the second doped layer ( 16 ) by the high temperature generated by the first laser ( 3 ).
10 . The method according to claim 8 , wherein the first laser ( 3 ) and the second laser ( 4 ) are emitted by different laser emitters, and one of the laser emitters emits more than three laser of different wavelengths.
11 . The method according to claim 8 , wherein said directing a second laser ( 4 ) through the doping reagent ( 2 ) into the third plane ( 14 ) to diffuse the target element of the second doped layer ( 16 ) to the first doped layer ( 15 ) comprises: directing the second laser ( 4 ) through the doping reagent ( 2 ), the first plane ( 12 ), and the second plane ( 13 ) into the third plane ( 14 ), and generating a high temperature; and driving the target element to be diffused to the first doped layer ( 15 ) by the high temperature generated by the second laser ( 4 ).
12 . The method according to claim 8 , wherein a wavelength L1 of the first laser ( 3 ) satisfies: 300 nm≤L1≤400 nm.
13 . The method according to claim 12 , wherein a wavelength L1 of the first laser ( 3 ) satisfies: 350 nm≤L1≤390 nm.
14 . The method according to claim 8 , wherein a wavelength L2 of the second laser ( 4 ) satisfies: 400 nm≤L2≤550 nm, and L1<L2.
15 . The method according to claim 8 , wherein energy density W1 of the first laser ( 3 ) satisfies: 0.4 J/cm 2 ≤W1≤1.5 J/cm 2 .
16 . The method according to claim 8 , wherein energy density W2 of the second laser ( 4 ) satisfies: 0.6 J/cm 2 ≤W2≤1.8 J/cm 2 .
17 . The method according to claim 8 , wherein, after said doping the target element, the method further comprises: removing the doping reagent ( 2 ) remaining on the first plane ( 12 ).

Description

TECHNICAL FIELD The present disclosure relates to the technical field of photovoltaic cells, and in particular, to a photovoltaic cell and a method for manufacturing a photovoltaic cell. BACKGROUND A photovoltaic cell is provided with a selective emitter to improve operation efficiency of the photovoltaic cell. During manufacturing of the selective emitter, a target element is driven into a first doped layer of a semiconductor substrate, and at the same time, the target element is diffused into a deeper second doped layer inside the substrate to realize doping of the semiconductor substrate. In the related art, the substrate is doped with a laser of a single wavelength, or doped by a post-oxidation process, leading to a rapid decrease in doping concentration of the first doped layer along a thickness direction, and making local concentration of the first doped layer lower, thereby reducing electrical properties of the substrate. SUMMARY The present disclosure provides a photovoltaic cell, which can reduce a rate of change of doping concentration of a first doped layer. According to a first aspect of the present disclosure, a photovoltaic cell is provided, including: a substrate including an emitter disposed in the substrate and a passivation layer stacked on a side of the emitter away from the substrate; the emitter including a first plane and a second plane laminated along a thickness direction of the emitter, and part of the emitter between the second plane and the first plane being a first doped layer; and within a unit volume, a rate of change ΔC1 between doping concentration of the second plane and doping concentration of the first plane satisfying: ΔC1≤15%. In the present disclosure, ΔC1≤15%, which reduces a risk of a rapid decrease in doping concentration of the first doped layer along the thickness direction, thereby improving consistency of the doping concentration of the first doped layer, reduces a risk of higher contact resistivity between the emitter and a metal electrode caused by lower local doping concentration of the first doped layer, and facilitates electrical connection between the emitter and the metal electrode, thereby improving conversion efficiency of the photovoltaic cell and improving operation stability of the photovoltaic cell. In an embodiment, a third plane is provided on a side of the second plane away from the first plane, and part of the emitter between the third plane and the second plane is a second doped layer; and a rate of change ΔC2 between doping concentration of the third plane and the doping concentration of the second plane satisfies: ΔC2≤30%. In an embodiment, a distance H1 between the second plane and the first plane satisfies: 0.3 μm≤H1≤0.35 μm; and a distance H2 between the third plane and the first plane satisfies: 0.5 μm≤H2≤0.7 μm. In an embodiment, within a unit volume, a rate of change ΔC3 between doping concentration at a first position of the second plane and doping concentration at a second position of the second plane satisfies: ΔC3≤25%. According to a second aspect of the present disclosure, a method for manufacturing the photovoltaic cell described above is provided, the method including: doping a target element into the substrate to form the emitter; and manufacturing the passivation layer on the first plane of the emitter. In an embodiment, a third plane is provided on a side of the second plane away from the first plane, and the doping a target element into the substrate includes: coating the first plane with a doping reagent containing the target element; directing a first laser through the doping reagent into the second plane to diffuse the target element to the first doped layer and the second doped layer; and directing a second laser through the doping reagent into the third plane to diffuse the target element of the second doped layer to the first doped layer. In an embodiment, the directing a first laser through the doping reagent into the second plane to diffuse the target element to the first doped layer and the second doped layer includes: directing the first laser through the doping reagent and the first plane into the second plane, and generating a high temperature; and driving the target element into the first doped layer by the first laser and further driving the target element to diffuse to the second doped layer by the high temperature generated by the first lase. In an embodiment, the directing a second laser through the doping reagent into the third plane to diffuse the target element of the second doped layer to the first doped layer includes: directing the second laser through the doping reagent, the first plane, and the second plane into the third plane, and generating a high temperature; and driving the target element to diffuse to the first doped layer by the high temperature generated by the second laser. In an embodiment, a wavelength L1 of the first laser satisfies: 300 nm≤L1≤400 nm, a wavelength L2 of the second laser sat