Solar cell, module, cell, and method of manufacturing the same

Abstract

This application relates to the field of solar cell technology, providing a solar cell, module, cell, and method for fabricating the same. The solar cell includes: a substrate; a first front working area located on the front side of the substrate; a second front working area located on the front side of the substrate; a front isolation area located on the front side of the substrate, between the first and second front working areas; a first back working area located on the back side of the substrate; a second back working area located on the back side of the substrate; and a back isolation area located on the back side of the substrate, between the first and second back working areas. The solar cell provided by the embodiments of this application can improve power output.

Description

Technical Field

[0001] This application belongs to the field of solar cell technology, and more specifically, relates to a solar cell, module, cell and method of preparation thereof. Background Technology

[0002] Through continuous technological advancements, solar cell conversion efficiency has surpassed the 25% threshold. In particular, TOPCon (Tunnel Oxide Passivated Contact) solar cells, a type of tunnel oxide passivated contact solar cell technology based on the selective carrier principle, significantly reduce carrier recombination losses due to their highly efficient passivation of an ultra-thin tunnel oxide layer and a doped polycrystalline silicon layer on the back side, achieving high open-circuit voltage and high conversion efficiency. To reduce series resistance and obtain higher current at the module end, non-destructive slicing methods are typically used to cut the entire solar cell into half-cells or multiple cells, ultimately forming a cell module based on sliced ​​cells. However, currently, sliced ​​solar cells suffer from leakage current, which reduces output power. Summary of the Invention

[0003] Embodiments of this application provide a solar cell, module, cell, and method for fabricating the same, which can improve power output.

[0004] In a first aspect, embodiments of this application provide a solar cell, comprising:

[0005] Matrix; The first working area is located on the front side of the substrate; The second working area is located on the front side of the substrate; The front isolation area is located on the front side of the substrate and between the first front working area and the second front working area; The first working area on the back side is located on the back side of the substrate; The second working area on the back side is located on the back side of the substrate; The back isolation area is located on the back side of the substrate and between the back first working area and the back second working area.

[0006] In some possible embodiments of the first aspect, the solar cell further includes: The first edge isolation area on the front is located on the side of the first working area on the front that is away from the second working area on the front. The front second edge isolation area is located on the side of the front second working area that is away from the front first working area; The first edge isolation area on the back side is located on the side of the first working area on the back side that is away from the second working area on the back side. The second edge isolation area on the back is located on the side of the second working area on the back away from the first working area on the back.

[0007] In some possible implementations of the first aspect, the portion of the substrate located in the first working area on the front side has a velvety texture; The portion of the substrate located in the second working area on the front side has a velvety texture.

[0008] In some possible implementations of the first aspect, the frontal isolation area includes: The first sub-isolation area on the front is located on the front of the substrate and on the side of the first working area on the front that is close to the second working area on the front. The second sub-isolation area on the front is located on the front of the substrate and on the side of the second working area on the front that is close to the first working area on the front. The third sub-isolation area on the front is located between the first sub-isolation area on the front and the second sub-isolation area on the front. The third sub-isolation area on the front has a velvet surface structure.

[0009] In some possible implementations of the first aspect, the back-side isolation region includes: The first sub-isolation area on the back is located on the back of the substrate and on the side of the first working area on the back that is close to the second working area on the back. The second sub-isolation area on the back is located on the back of the substrate and on the side of the second working area on the back that is close to the first working area on the back. The third sub-isolation region on the back is located between the first sub-isolation region on the back and the second sub-isolation region on the back.

[0010] Secondly, embodiments of this application provide a solar cell, comprising: Matrix; The front working area is located on the front side of the substrate; The front isolation area is located on the front side of the substrate and on one side of the front working area; The back working area is located on the back side of the substrate; The back isolation area is located on the back of the substrate and on one side of the back working area.

[0011] In some possible embodiments of the second aspect, the solar cell further includes: A front edge isolation area is located on the side of the front working area away from the front isolation area; The back edge isolation area is located on the side of the back working area away from the back isolation area.

[0012] Thirdly, embodiments of this application provide a solar module including the solar cell described in any of the above claims.

[0013] Fourthly, embodiments of this application provide a method for preparing a solar cell, the method comprising: A working area is prepared on the front side of the substrate, and a working area is prepared on the back side of the substrate; A portion of the working area on the front side of the substrate is removed to form a front isolation area; A portion of the working area on the back side of the substrate is removed to form a back isolation area; The front isolation area, the back isolation area, and the remaining working area are surface treated to complete the fabrication of the solar cell; The solar cell is cut open within the front isolation area to divide it into at least two solar cell wafers.

[0014] In some possible embodiments of the fourth aspect, prior to surface treatment of the front isolation region, the back isolation region, and the remaining working region to complete the fabrication of the solar cell, the following steps are also included: Remove a portion of the working area on both sides of the front side of the substrate to form a first edge isolation area and a second edge isolation area on the front side. A portion of the working area on both sides of the back side of the substrate is removed to form a first edge isolation area and a second edge isolation area on the back side.

[0015] The beneficial effects of the embodiments of this application are: By isolating the entire solar cell (or solar cell) through front and back isolation areas, double-sided isolation of the solar cell (or solar cell) can be achieved, which can reduce junction leakage and improve power. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 A cross-sectional view of a solar cell provided in an embodiment of this application; Figure 2A cross-sectional view of a solar cell provided in another embodiment of this application; Figure 3 A cross-sectional view of a solar cell provided in an embodiment of this application; Figure 4 A schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application; Figure 5 A schematic flowchart illustrating a method for fabricating a solar cell according to another embodiment of this application; Figure 6 This is a cross-sectional view of the solar cell of Experimental Example 1 of this application; Figure 7 This is a topographic image of the textured surface structure on the front side of the solar cell of Experimental Example 1 of this application; Figure 8 This is a cross-sectional view of the textured surface structure on the front side of the solar cell of Experimental Example 1 of this application; Figure 9 This is a cross-sectional view of the front isolation region of the solar cell in Experimental Example 1 of this application; Figure 10 This is a cross-sectional view of the solar cell of Experimental Example 2 of this application; Figure 11 This is a topographic view of the front isolation region of the solar cell in Experimental Example 2 of this application; Figure 12 This is a topographic view of the back isolation region of the solar cell in Experimental Example 2 of this application; Figure 13 This is a cross-sectional view of a comparative solar cell. Detailed Implementation

[0018] To make the technical problem to be solved, the technical solution and the beneficial effects of this application clearer, the following is in conjunction with the appendix. Figures 1 to 13 The present application will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

[0019] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0020] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0021] It should be understood that the term "and / or" as used in this application specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0023] Embodiments of this application provide a solar cell, a solar module, a solar cell wafer, and a method for preparing a solar cell.

[0024] Figure 1 This is a cross-sectional view of a solar cell provided according to an embodiment of this application. (See reference) Figure 1 The solar cell provided in the embodiments of this application includes a substrate 10, a front first working area 11, a front second working area 12, a front isolation area 2, a back first working area 31, a back second working area 32, and a back isolation area 4.

[0025] The substrate 10 is the main structure of the solar cell. The substrate 10 can be a silicon substrate, a silicon carbide substrate, or a gallium nitride substrate.

[0026] The aforementioned silicon substrate can specifically be an N-type silicon substrate; the N-type silicon substrate can specifically be a phosphorus-doped monocrystalline silicon wafer, an arsenic-doped monocrystalline silicon wafer, or an antimony-doped monocrystalline silicon wafer. The resistivity of the silicon substrate can be 0.1 Ω·cm to 100 Ω·cm. Silicon substrates within this resistivity range can help improve the migration speed of charge carriers, thereby improving the performance of solar cells.

[0027] The thickness of the silicon substrate can be 100μm-500μm. A silicon substrate that is too thin will reduce the light utilization efficiency, while a silicon substrate that is too thick will increase the resistance loss. By selecting the appropriate silicon substrate thickness, the light absorption efficiency and the current collection efficiency can be balanced.

[0028] The solar cell has a front side and a back side; the front side is the side used to receive sunlight, and the back side is the side that faces away from sunlight. The substrate 10 also has a front side and a back side. The front side of the substrate 10 is on the same side as the front side of the solar cell, and the back side of the substrate 10 is on the same side as the back side of the solar cell.

[0029] The first working area 11 on the front is used to receive sunlight for power generation. The first working area 11 on the front is located on the front of the substrate 10.

[0030] The front-side first working area 11 may include a front-side first emitter 111 (e.g., a P-type emitter or an N-type emitter), a front-side first passivation layer 112, and a front-side first electrode 113, which are sequentially disposed on the front side of the substrate 10 from the inside out. The doping concentration of the P-type emitter can be 1 × 10⁻⁶. 18 atoms / cm 3 Up to 1 × 10 19 atoms / cm 3 A suitable doping concentration in the P-type emitter can improve electrical performance and form a good PN junction, while avoiding excessive doping that can lead to boron-rich layers and carrier recombination losses.

[0031] The junction depth of the P-type emitter can be from 0.1 μm to 2 μm. This junction depth can optimize carrier collection efficiency, reduce junction recombination losses, and improve the open-circuit voltage and overall performance of the solar cell.

[0032] The second working area 12 on the front is used to receive sunlight for power generation. The second working area 12 on the front is located on the front of the substrate 10.

[0033] The structure of the second working area 12 on the front side is the same as that of the first working area 11 on the front side. The second working area 12 on the front side may include a second emitter 121 (such as a P-type emitter or an N-type emitter), a second passivation layer 122 on the front side, and a second electrode 123 on the front side. The second emitter 121, the second passivation layer 122, and the second electrode 123 are arranged sequentially from the inside to the outside on the front side of the substrate 10.

[0034] The first working area 11 and the second working area 12 on the front side can be collectively referred to as the front working area of ​​the solar cell.

[0035] The front isolation area 2 is located on the front of the substrate 10 and between the front first working area 11 and the front second working area 12.

[0036] The front isolation area 2 can be a velvety or polished structure.

[0037] refer to Figure 1 The first working region 31 on the back side is located on the back side of the substrate 10. The first working region 31 on the back side may include a first tunneling oxide layer 311 on the back side, a first doped layer 312 on the back side (such as an N-type doped polysilicon layer or a P-type doped polysilicon layer), a first passivation layer 313 on the back side, and a first electrode 314 on the back side. The first tunneling oxide layer 311, the first doped layer 312, the first passivation layer 313, and the first electrode 314 on the back side are disposed sequentially from the inside to the outside on the back side of the substrate 10.

[0038] The first working area 31 on the back side and the first working area 11 on the front side form a PN junction.

[0039] The second working region 32 on the back side is located on the back side of the substrate 10. The structure of the second working region 32 on the back side is the same as that of the first working region 31 on the back side. The second working region 32 on the back side may include a second tunneling oxide layer 321 on the back side, a second doped layer 322 on the back side (such as an N-type doped polysilicon layer or a P-type doped polysilicon layer), a second passivation layer 323 on the back side, and a second electrode 324 on the back side. The second tunneling oxide layer 321, the second doped layer 322, the second passivation layer 323, and the second electrode 324 on the back side are disposed sequentially from the inside to the outside on the back side of the substrate 10.

[0040] The tunneling oxide layer comprises one or more of silicon oxide, silicon nitride, and aluminum oxide. The thickness of the tunneling oxide layer can range from 0.1 nm to 3.0 nm. The combination of materials and thickness of the tunneling oxide layer can adjust its conductivity and dielectric properties, thereby improving the photoelectric conversion efficiency and stability of the solar cell.

[0041] The thickness of the doped layer can range from 50 nm to 300 nm. Controlling the thickness of the doped layer within this range can improve passivation and dielectric properties, and reduce the contact resistance of the metal electrode.

[0042] The passivation layer described above may include at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride. The passivation layer helps reduce surface defects and recombination, avoids current recombination losses, and improves battery stability and conversion efficiency.

[0043] The aforementioned electrodes can be at least one of silver, silver alloy, copper, copper alloy, or nickel-copper-silver multilayer electrodes. These metallic materials ensure good conductivity, stability, and corrosion resistance during long-term use, thereby optimizing the current conduction performance and efficiency of the solar cell. The double-sided passivation layers on the front and back of the solar cell suppress surface carrier recombination, optimize light absorption and selective carrier transport, and maximize open-circuit voltage, short-circuit current, and photoelectric conversion efficiency.

[0044] The second working area 32 on the back side and the second working area 12 on the front side form a PN junction.

[0045] The back isolation region 4 is located on the back of the substrate 10, and is located between the back first working region 31 and the back second working region 32.

[0046] The back isolation area 4 can be a velvet or polished surface.

[0047] The back isolation region 4 includes a passivation layer disposed on the back side of the substrate 10.

[0048] In the height direction H of the solar cell, the front isolation region 2 is located directly above the back isolation region 4.

[0049] To improve power generation efficiency, solar cells need to be divided into two solar cells. (Reference) Figure 2 Specifically, the solar cell is cut in half into two solar cells within the front isolation region 2. Since the front isolation region 2 and the back isolation region 4 are directly opposite each other in the height direction H, the solar cell is also cut in half into two solar cells within the back isolation region 4. Each solar cell has half of the front isolation region 2 and half of the back isolation region 4.

[0050] refer to Figure 1 A solar cell is cut in half to form two solar cell sheets. One solar cell sheet has a front first working area 11, a half of the substrate 10, a back first working area 31, a half of the front isolation area 2, and a half of the back isolation area 4. The half of the front isolation area 2 and the half of the back isolation area 4 isolate the solar cell sheet, achieving double-sided isolation. The other solar cell sheet has a front second working area 12, another half of the substrate 10, a back second working area 32, another half of the front isolation area 2, and another half of the back isolation area 4. The other half of the front isolation area 2 and the other half of the back isolation area 4 together isolate the solar cell sheet, achieving double-sided isolation.

[0051] As can be seen from the above, by isolating the entire solar cell (or solar cell) through the front isolation area 2 and the back isolation area 4, double-sided isolation of the solar cell (or solar cell) can be achieved, which can reduce junction leakage and improve power.

[0052] refer to Figure 1 The aforementioned solar cell may further include a first edge isolation region 51 on the front side and a second edge isolation region 52 on the front side.

[0053] The first edge isolation region 51 is located on the side of the first working area 11 away from the second working area. Thus, the first working area 11 is located between the first edge isolation region 51 and the front isolation region 2, and the first edge isolation region 51 and the front isolation region 2 together isolate the first working area 11.

[0054] The shape of the first edge isolation area 51 on the front can be linear, strip-shaped, or rectangular.

[0055] The front second edge isolation region 52 is located on the side of the front second working region 12 that is away from the front first working region 11. Thus, the front second working region 12 is located between the front isolation region 2 and the front second edge isolation region 52, and the front isolation region 2 and the front second edge isolation region 52 jointly isolate the front second working region 12.

[0056] The shape of the second edge isolation area 52 on the front can be linear, strip-shaped, or rectangular.

[0057] The first edge isolation region 51 and the second edge isolation region 52 on the front can have a velvety texture.

[0058] The height difference D1 between the substrate of the velvet structure in the front working area and the substrate of the velvet structure in the front isolation area 2 or the front edge isolation area can be 0 μm to 10 μm.

[0059] refer to Figure 1 The solar cell may further include a first edge isolation region 61 on the back and a second edge isolation region 62 on the back.

[0060] The first edge isolation region 61 on the back is located on the side of the first working area 31 on the back away from the second working area 32 on the back. Thus, the first working area 31 on the back is located between the first edge isolation region 61 on the back and the back isolation region 4, and the first edge isolation region 61 on the back and the back isolation region 4 together isolate the first working area 31 on the back.

[0061] The shape of the first edge isolation area 61 on the back can be linear, strip-shaped, or rectangular.

[0062] The first edge isolation region 61 on the back side includes a passivation layer disposed on the back side of the substrate 10.

[0063] The second edge isolation region 62 on the back is located on the side of the second working area 32 on the back away from the first working area 31 on the back. Thus, the second working area 32 on the back is located between the back isolation region 4 and the second edge isolation region 62 on the back, and the back isolation region 4 and the second edge isolation region 62 on the back together isolate the second working area 32 on the back.

[0064] The shape of the second edge isolation area 62 on the back can be linear, strip-shaped, or rectangular.

[0065] The second edge isolation region 62 on the back side includes a passivation layer disposed on the back side of the substrate 10.

[0066] The combination of the front isolation region and the front edge isolation region, as well as the combination of the back isolation region and the back edge isolation region, can prevent the exposed substrate surface of the cut section from forming dangling bonds and defect states due to damage, which would become strong recombination centers for charge carriers. As the perimeter-area ratio of the battery increases, edge recombination becomes more and more serious, leading to a significant loss of battery efficiency after slicing, thus improving power output.

[0067] The minimum processing width of the front isolation region 2 can be from 0 μm to 150 μm, the minimum processing width of the front first edge isolation region 51 and the front second edge isolation region 52 can be from 0 μm to 150 μm, the minimum processing width of the back isolation region 4 can be from 0 μm to 150 μm, and the minimum processing width of the back first edge isolation region 61 and the back second edge isolation region 62 can be from 0 μm to 150 μm. This range of isolation region sizes balances the isolation effect, passivation effect, and light utilization of the edge isolation regions. It also allows for a larger working window for halving (e.g., laser cutting) of solar cells, which helps improve the alignment of subsequent slicing, resulting in better module efficiency and simultaneously meeting the requirements of different application scenarios for withstand voltage, appearance, and quality reliability.

[0068] refer to Figure 1 The portion of the substrate 10 located in the first working area 11 on the front side has a textured surface 110. The textured surface 110 is a pyramid-shaped structure. Specifically, the entire portion of the substrate 10 located in the first working area 11 on the front side has a textured surface, or only a portion of the portion of the substrate 10 located in the first working area 11 on the front side has a textured surface.

[0069] refer to Figure 1 The portion of the substrate 10 located in the second working area 12 on the front side has a felt structure 120. The felt structure 120 is a pyramid-shaped structure. Specifically, the entire portion of the substrate 10 located in the second working area 12 on the front side has a felt structure, or only a portion of the portion of the substrate 10 located in the second working area 12 on the front side has a felt structure.

[0070] The textured surface of the front working area (such as the first front working area 11 and the second front working area 12) can reduce light reflection loss, thereby enhancing light utilization efficiency and improving the photoelectric conversion performance of the solar cell.

[0071] refer to Figure 1The aforementioned frontal isolation area 2 may include a frontal first sub-isolation area 21, a frontal second sub-isolation area 22, and a frontal third sub-isolation area 23.

[0072] The first sub-isolation region 21 is located on the front side of the substrate 10, and is located on the side of the first working region 11 on the front side close to the second working region 12 on the front side. Thus, the first working region 11 on the front side is located between the first edge isolation region 51 on the front side and the first sub-isolation region 21 on the front side.

[0073] The shape of the first sub-isolation area 21 on the front can be rectangular.

[0074] The second sub-isolation region 22 is located on the front side of the substrate 10, and is located on the side of the second working region 12 on the front side close to the first working region 11 on the front side. Thus, the second working region 12 on the front side is located between the second sub-isolation region 22 on the front side and the second edge isolation region 52 on the front side.

[0075] The shape of the second sub-isolation area 22 on the front can be rectangular.

[0076] The third sub-isolation area 23 on the front is located between the first sub-isolation area 21 on the front and the second sub-isolation area 22 on the front.

[0077] The first sub-isolation area 21 and the second sub-isolation area 22 on the front can have a velvety texture. Alternatively, Figure 2 A cross-sectional view of a solar cell provided in another embodiment of this application, with reference to... Figure 2 The first sub-isolation area 21 and the second sub-isolation area 22 on the front side are polished structures.

[0078] The third sub-isolation area 23 on the front can be a velvet-textured structure.

[0079] The solar cell is cut in half into two solar cell sheets in the front third sub-isolation region 23. One solar cell sheet has a front first sub-isolation region 21 and half of the front third sub-isolation region 23, and the other solar cell sheet has a front second sub-isolation region 22 and the other half of the front third sub-isolation region 23.

[0080] refer to Figure 1 The aforementioned back isolation area may include a first back sub-isolation area 41, a second back sub-isolation area 42, and a third back sub-isolation area 43.

[0081] The first sub-isolation region 41 on the back side is located on the back side of the substrate 10, and is located on the side of the first working region 31 on the back side near the second working region 32 on the back side. Thus, the first working region 31 on the back side is located between the first edge isolation region 61 on the back side and the first sub-isolation region 41 on the back side.

[0082] The shape of the first sub-isolation area 41 on the back can be rectangular.

[0083] The second sub-isolation region 42 on the back side is located on the back side of the substrate 10, and is located on the side of the second working region 32 on the back side near the first working region 31 on the back side. Thus, the second working region 32 on the back side is located between the second sub-isolation region 42 on the back side and the second edge isolation region 62 on the back side.

[0084] The shape of the second sub-isolation region 42 on the back side can be rectangular. Regular isolation patterns can be quickly and accurately controlled by laser patterning, which can ensure the isolation of the PN junction, facilitate matching with the vertical arrangement of the gate electrodes, and quickly adapt to the needs of multi-segmentation.

[0085] The third sub-isolation region 43 on the back is located between the first sub-isolation region 41 on the back and the second sub-isolation region 42 on the back.

[0086] The height difference D2 between the structural substrate of the back working area and the structural substrate of the back isolation area can be 0 to 4 μm.

[0087] As can be seen from the above, the double-line isolation of the front side of the solar cell is achieved by the first sub-isolation region 21 and the second sub-isolation region 22 on the front side, and the double-line isolation of the back side of the solar cell is achieved by the first sub-isolation region 41 and the second sub-isolation region 42 on the back side. This can reduce the area of ​​grooving (such as laser grooving) and reduce the damage caused by grooving (such as laser grooving). At the same time, the third sub-isolation region 23 on the front side has a textured surface structure, which can ensure that the cutting position when the solar cell is cut in half is still textured, which can reduce the dicing power and reduce thermal damage.

[0088] The solar cell provided in the embodiments of this application is obtained by cutting the solar cell provided in the embodiments of this application in half.

[0089] Figure 3 This is a cross-sectional view of a solar cell provided in one embodiment of this application. (Reference) Figure 3 The solar cell provided in the embodiments of this application includes a substrate 10, a front working area 1A, a front isolation area 2A, a back working area 3A, and a back isolation area 4A.

[0090] The substrate 10 is the main structure of the solar cell. The substrate 10 can be a silicon substrate, a silicon carbide substrate, or a gallium nitride substrate.

[0091] The front working area 1A is located on the front side of the substrate 10. Specifically, the front working area 1A can be either the front first working area 11 or the front second working area 12.

[0092] The front isolation region 2A is located on the front side of the substrate 10 and is located on one side of the front working region 1A. Specifically, the front isolation region 2A can be half of the front isolation region 2.

[0093] The back working area 3A is located on the back side of the substrate 10. Specifically, the back working area 3A can be either the back first working area 31 or the back second working area 32.

[0094] The back isolation region 4A is located on the back side of the substrate 10 and is located on one side of the back working region 3A. Specifically, the back isolation region 4A can be half of the back isolation region 4.

[0095] The front isolation region 2A and the back isolation region 4A work together to isolate the solar cell, achieving double-sided isolation.

[0096] As can be seen from the above, by isolating the entire solar cell through the front isolation region 2A and the back isolation region 4A, double-sided isolation of the solar cell can be achieved, which can reduce junction leakage and improve power.

[0097] refer to Figure 3 The aforementioned solar cell may also include a front edge isolation region 5A and a back edge isolation region 6A.

[0098] The front edge isolation area 5A is located on the side of the front working area 1A that is away from the front isolation area 2A. Thus, the front working area 1A is located between the front edge isolation area 5A and the front isolation area 2A, and the front edge isolation area 5A and the front isolation area 2A together isolate the front working area 1A.

[0099] The front edge isolation area 5A can specifically be the front first edge isolation area 51 or the front second edge isolation area 52.

[0100] The back edge isolation region 6A is located on the side of the back working region 3A away from the back isolation region 4A. Thus, the back working region 3A is located between the back edge isolation region 6A and the back isolation region 4A, and the back edge isolation region 6A and the back isolation region 4A together isolate the back working region 3A.

[0101] The rear edge isolation area 6A can specifically be the rear first edge isolation area 61 or the rear second edge isolation area 62.

[0102] An embodiment of this application provides a solar module comprising the solar cell provided in any of the above embodiments.

[0103] The solar module provided in the embodiments of this application may specifically be a solar panel comprising multiple solar cells.

[0104] The method for preparing the solar cell provided in the embodiments of this application is used to prepare the solar cell provided in the embodiments of this application. Specifically, the solar cell provided in the embodiments of this application is prepared first, and then the solar cell provided in the embodiments of this application is prepared.

[0105] Figure 4 This is a schematic flowchart illustrating a method for fabricating a solar cell according to an embodiment of this application. (Reference) Figure 4 The method for preparing a solar cell provided in the embodiments of this application includes steps A1 to A5.

[0106] Step A1: Prepare the working area on the front side of the substrate and prepare the working area on the back side of the substrate.

[0107] The working area on the front side of the substrate 10 is the front working area. The working area on the back side of the substrate 10 is the back working area.

[0108] The front working area may include an emitter (such as a P-type emitter or an N-type emitter), a passivation layer, and an electrode. Specifically, step A1 involves fabricating an emitter (such as a P-type emitter or an N-type emitter), a passivation layer, and an electrode on the front side of the substrate 10.

[0109] The back working area may include a tunneling oxide layer, a doped polysilicon layer (such as an N-type doped polysilicon layer or a P-type doped polysilicon layer), a passivation layer, and an electrode. Specifically, step A1 is to prepare a tunneling oxide layer, a doped polysilicon layer (such as an N-type doped polysilicon layer or a P-type doped polysilicon layer), a passivation layer, and an electrode on the back side of the substrate 10.

[0110] Step A1 of the above-mentioned method for preparing a solar cell (i.e., preparing a working area on the front side of the substrate and preparing a working area on the back side of the substrate) may include: texturing the front side of the substrate 10 to form a textured structure on the front side of the substrate 10; preparing an emitter (e.g., a P-type emitter) on the front side of the texturized substrate; and preparing a tunneling oxide layer and a doped layer (e.g., an N-type doped polycrystalline silicon layer) on the back side of the substrate.

[0111] Step A2: Remove a portion of the working area on the front side of the substrate to form a front isolation area.

[0112] The front side of the substrate 10 has an emitter and a passivation layer. In order to form a front isolation region, the emitter and passivation layer are removed at a predetermined position on the front side of the substrate 10, for example, by removing the emitter and passivation layer with a laser.

[0113] Step A3: Remove a portion of the working area on the back side of the substrate to form a back isolation area.

[0114] The back side of the substrate 10 has a tunneling oxide layer, a doped polysilicon layer, and a passivation layer. In order to form a back-side isolation region, the back junction is removed at a predetermined location on the back side of the substrate 10, for example, by removing the tunneling oxide layer, the doped polysilicon layer, and the passivation layer using a laser.

[0115] Step A4: Perform surface treatment on the front isolation area, the back isolation area, and the remaining working area to complete the fabrication of the solar cell.

[0116] After removing the working area of ​​the substrate, surface treatments such as cleaning and passivation are required for solar cell fabrication to obtain the solar cell. As an example, the front and back isolation areas are cleaned with acid and alkali solutions; an Al2O3 film is deposited on the front side of the substrate using atomic layer deposition; and SiN plating is performed on both the front and back sides using plasma-enhanced chemical vapor deposition. x Thin film deposition to achieve passivation on both the front and back sides.

[0117] Step A4 of the above-mentioned method for preparing solar cells (i.e., surface treatment of the front isolation area, the back isolation area, and the remaining working area to complete the preparation of the solar cell) may include: cleaning the surface of the substrate, such as removing the wound phosphosilicate glass and wound borosilicate phosphosilicate glass on the front side to ensure the cleanliness of the substrate surface; passivating the entire front side and the entire back side to form a passivation layer on the front side and the back side; and setting electrodes on the front side and the back side to complete the preparation of the solar cell.

[0118] Step A5: Cut the solar cell in the front isolation area to divide the solar cell into at least two solar cell panels.

[0119] To cut solar cells into solar panels for manufacturing solar modules, the solar cells need to be diced. This can be done non-destructively using a laser, with cuts made in the front and back insulation areas. The resulting solar panels are then used in the string bonding process to complete the fabrication of the subsequent solar modules.

[0120] As can be seen from the above, by setting a front isolation area on the front side of the substrate and a back isolation area on the back side of the substrate, and cutting the solar cell in the front isolation area to divide the solar cell into at least two solar cells, the entire solar cell can be isolated by the front isolation area and the back isolation area, which can achieve double-sided isolation of the solar cell, reduce junction leakage, and improve power.

[0121] In addition, by cleaning the surface of the substrate to remove the winding phosphosilicate glass and winding borosilicate phosphosilicate glass, and then performing passivation, the high-temperature annealing process and half-wafer testing can be avoided, which can reduce costs.

[0122] Figure 5 This is a schematic flowchart illustrating a method for fabricating a solar cell according to another embodiment of this application. (Reference) Figure 5 The above-mentioned method for preparing solar cells may include steps B1 and B2 before step A4 (i.e., surface treatment of the front isolation area, the back isolation area, and the remaining working area to complete the preparation of the solar cell).

[0123] Step B1: Remove a portion of the working area on both sides of the front of the substrate to form the first edge isolation area and the second edge isolation area on the front.

[0124] In order to form an edge isolation area on the front side of the substrate, a portion of the working area is removed on both sides of the front side of the substrate, which can be done by laser removal.

[0125] Step B2: Remove a portion of the working area on both sides of the back side of the substrate to form the first edge isolation area and the second edge isolation area on the back side.

[0126] In order to form an edge isolation area on the back side of the substrate, a portion of the working area is removed on both sides of the back side of the substrate, which can be done by laser removal.

[0127] The laser used can have a wavelength range of 343nm to 1080nm, and can be either pulsed or continuous laser. The pulse width can be nanosecond, picosecond, or femtosecond, the laser power can be 0W to 500W, the laser repetition frequency can be 0 kHz to 4000 kHz, the laser processing spot type can be Gaussian or flat-top, and the laser processing spot shape can be at least one or more of the following: circular, linear, rectangular, square, and annular. The laser spot overlap rate can be 0% to 100%. These adjustable parameters allow for better and more controllable removal of the PN junction in the working area, and effectively eliminate thermal damage and mechanical stress.

[0128] The method for fabricating solar cells provided in this application, by adjusting the appropriate laser pulse width, frequency, spot size, and processing rate, can thoroughly remove the P-type emitter and N-type back junction in the isolation region. Simultaneously, the acid-alkali treatment in step A4 not only removes the plating but also further etches away the heat-damaged areas and molten material caused by the laser, maintaining a good passivation effect. Texturing the isolation region increases the etching depth and creates a textured surface, increasing the light absorption rate and effectively improving the short-circuit current. The synergistic effect of laser removal of the working area and acid-alkali treatment achieves effective PN junction isolation, reduces carrier recombination while controlling damage, broadens the processing window for better mass production, and increases the power output of the solar module.

[0129] The embodiments of this application are illustrated below through experimental examples and comparative examples.

[0130] Experimental Examples 1 and 2 show solar cells prepared according to the method provided in this application. The comparative example shows solar cells prepared using a commonly used method.

[0131] Experimental Example 1 Figure 6 This is a cross-sectional view of the solar cell of Experimental Example 1 of this application. (Reference) Figure 6 The prepared N-type silicon substrate is texturized to form a textured surface structure on the front side of the N-type silicon substrate.

[0132] High-temperature boron is diffused onto the surface of an N-type silicon substrate to form a P-type emitter and borosilicate glass (BSG) as the front and back working areas.

[0133] For the pre-defined isolation area on the front (i.e., the laser non-destructive cutting position), the P-type emitter is removed by laser etching to form the front isolation area. The front isolation area is a single rectangle with a width of 400μm. The parameters of the laser used are: wavelength of 532nm, pulse width of 15ps, power of 35W, frequency of 500kHz, spot overlap rate of 50%, flat-top light, and spot size of 150um.

[0134] The borosilicate glass on the back side is removed by single-sided HF acid etching, then the back side is alkali polished with KOH, and a tunneling oxide layer is generated by thermal oxidation and an intrinsic polycrystalline silicon layer is produced by low-pressure chemical vapor deposition. Subsequently, an N-type doped polycrystalline silicon layer and phosphosilicate glass (i.e., PSG) are formed on the surface after high-temperature phosphorus diffusion, and phosphosilicate glass and borosilicate glass (i.e., PBSG) are formed on the front side.

[0135] The phosphosilicate glass (PSG) and borosilicate glass (PBSG) coated on the front side are removed by HF pickling.

[0136] The borosilicate glass on the front and the phosphosilicate glass on the back are removed by HF pickling.

[0137] Al2O3 film was deposited on the front side of an N-type silicon substrate using atomic layer deposition, and SiN2O3 film was then applied to both the front and back sides using plasma-enhanced chemical vapor deposition. x Thin film deposition.

[0138] Silver paste was screen-printed onto the P-type emitter on the front side and the N-type doped polycrystalline silicon layer on the back side, respectively, followed by high-temperature sintering to achieve metallization. Finally, after light injection, an N-type TOPCon solar cell was obtained. The morphology of the textured surface structure on the front side of the cell, as captured by scanning electron microscopy, is shown below. Figure 7 As shown; a cross-sectional view of the textured surface of the battery's front side, obtained using a scanning electron microscope. Figure 8 As shown; a cross-sectional view of the front isolation area of ​​the battery obtained by photography is shown below. Figure 9 As shown.

[0139] Using a non-destructive laser scribing device, the solar cell is cut in half in the front isolation area to obtain two solar cell sheets, which can then be made into solar modules.

[0140] Experimental Example 2 Figure 10 This is a cross-sectional view of the solar cell in Experimental Example 2 of this application. (Reference) Figure 10 The prepared N-type silicon substrate is texturized to form a textured surface structure on the front side of the N-type silicon substrate.

[0141] High-temperature boron is diffused onto the surface of an N-type silicon substrate to form a P-type emitter and borosilicate glass (BSG) as the front and back working areas.

[0142] For the pre-defined isolation area on the front (i.e., the laser non-destructive cutting position), the P-type emitter is removed by laser etching to form the front isolation area; the front isolation area includes a first front sub-isolation area 21, a second front sub-isolation area 22, and a third front sub-isolation area 23. The first front sub-isolation area 21 and the second front sub-isolation area 22 are linear isolation areas, forming a double-line isolation area; the line width of the first front sub-isolation area 21 and the second front sub-isolation area 22 is 150um, the line spacing is 290um, and the width of the front isolation area is 590μm; the parameters of the laser used are: wavelength 532nm, pulse width 15ps, set power 35W, frequency 500kHz, spot overlap rate 50%, the spot is a flat-top light, and the spot size is 150um.

[0143] The borosilicate glass on the back side is removed by single-sided HF acid etching, then the back side is alkali polished with KOH, and a tunneling oxide layer is generated by thermal oxidation and an intrinsic polycrystalline silicon layer is produced by low-pressure chemical vapor deposition. Subsequently, an N-type doped polycrystalline silicon layer and phosphosilicate glass (i.e., PSG) are formed on the surface after high-temperature phosphorus diffusion, and phosphosilicate glass and borosilicate glass (i.e., PBSG) are formed on the front side.

[0144] The N-type back junction is removed by laser etching in the pre-defined isolation area on the back (i.e., the laser non-destructive cutting position) to form the back isolation area. The back isolation area includes a first back sub-isolation area 41, a second back sub-isolation area 42, and a third back sub-isolation area 43. The first back sub-isolation area 41 and the second back sub-isolation area 42 are linear isolation areas, forming a double-line isolation area. The line width of the first back sub-isolation area 41 and the second back sub-isolation area 42 is 150 μm, the line spacing is 290 μm, and the width of the back isolation area is 590 μm. The parameters of the laser used are: wavelength 532 nm, pulse width 15 ps, power setting 35 W, frequency 500 kHz, spot overlap rate 50%, and the spot is a flat-top light.

[0145] The phosphosilicate glass (PSG) and borosilicate glass (PBSG) coated on the front side are removed by HF pickling.

[0146] The borosilicate glass on the front and the phosphosilicate glass on the back are removed by HF pickling.

[0147] Al2O3 film was deposited on the front side of an N-type silicon substrate using atomic layer deposition, and SiN2O3 film was then applied to both the front and back sides using plasma-enhanced chemical vapor deposition. x Thin film deposition.

[0148] Silver paste was screen-printed onto the P-type emitter on the front side and the N-type doped polycrystalline silicon layer on the back side, respectively, followed by high-temperature sintering to achieve metallization. Finally, after light injection, an N-type TOPCon solar cell was obtained. A microscopic image of the front isolation region of the cell is shown below. Figure 11 As shown; the morphological image of the back isolation region of the battery obtained by microscopy is shown below. Figure 12 As shown.

[0149] Using a non-destructive laser scribing device, the solar cell is cut in half in the front isolation area to obtain two solar cell sheets, which can then be made into solar modules.

[0150] The process of laser etching the front and back sides to form isolation areas can be performed in the same step, that is, the grooving process on the front and back sides can be achieved simultaneously, while the other steps remain unchanged.

[0151] Comparative Example Figure 13 This is a cross-sectional view of a comparative solar cell. (Reference) Figure 13 The prepared N-type silicon substrate is texturized to form a textured surface structure on the front side of the N-type silicon substrate.

[0152] High-temperature boron is diffused onto the surface of an N-type silicon substrate to form a P-type emitter and borosilicate glass (BSG) as the front and back working areas.

[0153] The borosilicate glass on the back side was removed by single-sided HF acid etching, and then the back side was alkali polished with KOH.

[0154] A tunneling oxide layer is generated by thermal oxidation and an intrinsic polycrystalline silicon layer is produced by low-pressure chemical vapor deposition. Subsequently, an N-type doped polycrystalline silicon layer and phosphosilicate glass (PSG) are formed on the surface after high-temperature phosphorus diffusion, and phosphosilicate glass and borosilicate glass (PBSG) are formed on the front side.

[0155] The phosphosilicate glass (PSG) and borosilicate glass (PBSG) coated on the front side are removed by HF pickling.

[0156] The borosilicate glass on the front and the phosphosilicate glass on the back are removed by HF pickling.

[0157] Al2O3 film was deposited on the front side of an N-type silicon substrate using atomic layer deposition, and SiN2O3 film was then applied to both the front and back sides using plasma-enhanced chemical vapor deposition. x Thin film deposition.

[0158] Silver paste was printed on the P-type emitter on the front side and the N-type doped polycrystalline silicon layer on the back side using screen printing. Metallization was completed by high-temperature sintering. Finally, after light injection treatment, N-type TOPCon solar cells were obtained.

[0159] Using a non-destructive laser scribing device, the solar cells are cut in half at a set position to obtain two solar cell sheets, which can then be used to make solar modules.

[0160] The P values ​​of solar modules made from half-cells of TOPCon cells obtained in Experiment 1, Experiment 2, and the comparative example were measured. max V oc I sc The FF parameters are recorded in Table 1.

[0161] Table 1 shows the parameters of the solar modules corresponding to Experiment 1, Experiment 2, and the comparative example.

[0162] As shown in Table 1, the embodiments of this application can effectively improve the performance of solar cells, significantly reduce the cell efficiency loss caused by the slicing process, and increase the power of solar modules.

[0163] The solar cells, modules, cells, and their fabrication methods provided in the embodiments of this application can reduce testing steps, thereby reducing costs, while also enabling a more stable increase in power output.

[0164] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A solar cell, characterized in that, include: Matrix; The first working area is located on the front side of the substrate; The second working area is located on the front side of the substrate; The front isolation area is located on the front side of the substrate and between the first front working area and the second front working area; The first working area on the back side is located on the back side of the substrate; The second working area on the back side is located on the back side of the substrate; The back isolation area is located on the back side of the substrate and between the back first working area and the back second working area.

2. The solar cell as described in claim 1, characterized in that, Also includes: The first edge isolation area on the front is located on the side of the first working area on the front that is away from the second working area on the front. The front second edge isolation area is located on the side of the front second working area that is away from the front first working area; The first edge isolation area on the back side is located on the side of the first working area on the back side that is away from the second working area on the back side. The second edge isolation area on the back is located on the side of the second working area on the back away from the first working area on the back.

3. The solar cell as described in claim 1, characterized in that, The portion of the substrate located in the first working area on the front side has a velvety structure; The portion of the substrate located in the second working area on the front side has a velvety texture.

4. The solar cell as described in claim 1, characterized in that, The frontal isolation area includes: The first sub-isolation area on the front is located on the front of the substrate and on the side of the first working area on the front that is close to the second working area on the front. The second sub-isolation area on the front is located on the front of the substrate and on the side of the second working area on the front that is close to the first working area on the front. The third sub-isolation area on the front is located between the first sub-isolation area on the front and the second sub-isolation area on the front. The third sub-isolation area on the front has a velvet surface structure.

5. The solar cell according to any one of claims 1 to 4, characterized in that, The rear isolation area includes: The first sub-isolation area on the back is located on the back of the substrate and on the side of the first working area on the back that is close to the second working area on the back. The second sub-isolation area on the back is located on the back of the substrate and on the side of the second working area on the back that is close to the first working area on the back. The third sub-isolation region on the back is located between the first sub-isolation region on the back and the second sub-isolation region on the back.

6. A solar cell, characterized in that, include: Matrix; The front working area is located on the front side of the substrate; The front isolation area is located on the front side of the substrate and on one side of the front working area; The back working area is located on the back side of the substrate; The back isolation area is located on the back of the substrate and on one side of the back working area.

7. The solar cell as described in claim 6, characterized in that, Also includes: A front edge isolation area is located on the side of the front working area away from the front isolation area; The back edge isolation area is located on the side of the back working area away from the back isolation area.

8. A solar energy module, characterized in that, Includes the solar cell as described in claim 6 or 7.

9. A method for preparing a solar cell, characterized in that, The preparation method includes: A working area is prepared on the front side of the substrate, and a working area is prepared on the back side of the substrate; A portion of the working area on the front side of the substrate is removed to form a front isolation area; A portion of the working area on the back side of the substrate is removed to form a back isolation area; The front isolation area, the back isolation area, and the remaining working area are surface treated to complete the fabrication of the solar cell; The solar cell is cut open within the front isolation area to divide it into at least two solar cell wafers.

10. The preparation method according to claim 9, characterized in that, Before performing surface treatment on the front isolation area, the back isolation area, and the remaining working area to complete the fabrication of the solar cell, the following steps are also included: Remove a portion of the working area on both sides of the front side of the substrate to form a first edge isolation area and a second edge isolation area on the front side. A portion of the working area on both sides of the back side of the substrate is removed to form a first edge isolation area and a second edge isolation area on the back side.

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