Half-cell solar cell and its preparation process, photovoltaic module

Abstract

The present disclosure discloses a half-cell solar cell and its preparation process, and a photovoltaic module. The preparation process includes a first laser operation, a coating operation, and a second laser operation performed in sequence; wherein the first laser operation forms grooves at both ends of the non-gridline area of ​​the solar cell; the coating operation forms a passivation film on the groove surface of the groove; and the second laser operation splits the solar cell into two parts along the area between the two grooves. The solar cell of the present disclosure forms grooves at both ends of the non-gridline area, and a passivation film is set on the groove surface of the groove. After slicing, the split surface is not completely exposed. Compared with the prior art, the area of ​​the split surface where carriers are easily recombined is reduced, and the power generation loss of the battery is reduced to a certain extent. The grooves of the cell of the present disclosure can be formed in the battery manufacturing process. When the passivation film / anti-reflection film is deposited on the front and back of the cell, the passivation film is deposited in the grooves at the same time, and only laser slotting equipment needs to be added to the existing production line.

Description

Technical Field

[0001] The invention relates to the field of solar cell manufacturing, and in particular to a half-cell solar cell and a preparation process thereof, and a photovoltaic module. Background Art

[0002] With the gradual popularization of cell slicing, shingling, and tiling technologies, laser cutting technology has become the mainstream trend in the solar cell industry. In the component packaging process, solar cells need to be sliced ​​in advance. After the solar cell is sliced, the cut surface will become the center of carrier recombination, causing damage to the solar cell power generation. Summary of the invention

[0003] The half-cell solar cell and its preparation process, as well as the photovoltaic module provided by the present disclosure are intended to solve at least one technical problem mentioned in the prior art.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] The preparation process of a half-cell solar cell comprises at least the following steps:

[0006] sequentially performing a first laser operation, a coating operation, and a second laser operation;

[0007] Wherein, the first laser operation forms grooves at both ends of the non-gridline area of ​​the solar cell respectively;

[0008] The coating operation forms a passivation film on the groove surface of the groove;

[0009] The second laser operation splits the solar cell into two parts along the area between the two grooves.

[0010] In certain embodiments, the second laser operation comprises the following steps:

[0011] Forming a linear heating zone in the region of the solar cell between the two grooves;

[0012] The linear heating zone is cooled to split the solar cell into two parts.

[0013] In some embodiments, a cleaning operation is further included, wherein the cleaning operation is performed to clean the groove surface of the groove.

[0014] In certain embodiments, the passivation film includes one or more stacked layers of an aluminum oxide layer, a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or an aluminum nitride layer.

[0015] In some embodiments, the passivation film includes an aluminum oxide layer and a silicon nitride layer stacked in sequence; or, the passivation film includes an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer stacked in sequence.

[0016] In some embodiments, the front and back sides of the solar cell have both a first gridline region and a second gridline region, or only the back side has a first gridline region, the non-gridline region is located between the first gridline region and the second gridline region, and the non-gridline region extends from one side of the solar cell to the other along a first direction.

[0017] In some embodiments, the groove extends from an edge of the solar cell along a first direction and ends inside the solar cell.

[0018] In some embodiments, the extension length of the groove in the first direction is 1 mm to 10 mm, and the groove penetrates the solar cell in the thickness direction of the solar cell or has a depth less than the thickness of the solar cell.

[0019] The present disclosure also relates to a half-cell solar cell, which is manufactured by the above-mentioned manufacturing process of a half-cell solar cell, wherein the half-cell solar cell comprises a split section, wherein the split section comprises a first region and second regions located at both ends of the first region;

[0020] The morphology of the first region is different from the morphology of the second region;

[0021] The surface of the second region is covered with a passivation film.

[0022] In certain embodiments, the first region does not have the passivation film.

[0023] In certain embodiments, the passivation film includes one or more stacked layers of an aluminum oxide layer, a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer, or an aluminum nitride layer.

[0024] In some embodiments, the passivation film includes an aluminum oxide layer and a silicon nitride layer stacked in sequence; or, the passivation film includes an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer stacked in sequence.

[0025] In some embodiments, the width of the second region along the thickness direction of the half solar cell is equal to or less than the thickness of the half solar cell; the second region extends from the end of the dividing section along the length direction of the dividing section, and the length of the second region is 1 mm to 10 mm.

[0026] In certain embodiments, the second region has a laser ablated morphology and the first region has a mechanically fractured morphology.

[0027] The present disclosure also relates to a photovoltaic assembly, comprising a plurality of the above-mentioned half-cell solar cells, wherein the plurality of the half-cell solar cells are connected in series to form a cell string.

[0028] Due to the application of the above technical solution, the beneficial effects of the present disclosure compared with the prior art are:

[0029] (1) The solar cell disclosed in the present invention forms grooves at both ends of the non-gridline area, and a passivation film is provided on the groove surface. After slicing, the dividing surface is not completely exposed. Compared with the prior art, the area of ​​the dividing surface where carriers are easily recombined is reduced, thereby reducing the power generation loss of the battery to a certain extent.

[0030] (2) Depositing a passivation film / anti-reflection film on the front and back sides of the battery cell is a necessary process for manufacturing the battery cell. The grooves of the battery cell disclosed in the present invention can be formed in the battery manufacturing process. In the process of depositing a passivation film / anti-reflection film on the front and back sides of the battery cell, the passivation film is also deposited in the grooves. Except for adding laser groove cutting equipment on the basis of the existing production line, there is no need to make larger-scale modifications to the production line. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a schematic diagram of the process of preparing a half-cell solar cell in Example 1 of the present invention;

[0033] Figure 2 Schematic diagram of the cross-sectional structure of the passivation film in Example 1 of the present invention;

[0034] Figure 3 is a schematic structural diagram of a solar cell in Example 1 of the present invention;

[0035] Figure 4 is a schematic structural diagram of a solar cell in Example 2 of the present invention;

[0036] Figure 5 is a schematic structural diagram of a solar cell in Example 3 of the present invention;

[0037] Figure 6 is a schematic structural diagram of a solar cell in Example 4 of the present invention;

[0038] Figure 7Schematic diagram of the process of preparing a half-cell solar cell in Example 5 of the present invention;

[0039] Figure 8 This is a schematic structural diagram of a segmentation section in Example 6 of the present invention;

[0040] Fig. 9 This is a schematic structural diagram of another segmentation section in Embodiment 6 of the present invention;

[0041] Fig.10 This is a structural schematic diagram of another segmentation section in Embodiment 6 of the present invention;

[0042] Fig.11 This is a structural schematic diagram of another segmentation section in Embodiment 6 of the present invention;

[0043] Description of reference numerals:

[0044] 1-solar cell; 2-grooving; 3-passivation film; 31-aluminum oxide layer; 32-silicon oxide layer; 33-silicon nitride layer; 34-silicon oxynitride layer; 4-first region; 5-second region. DETAILED DESCRIPTION

[0045] In order to enable those skilled in the art to better understand the scheme of the present disclosure, the technical scheme in the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present disclosure.

[0046] It should be noted that the terms "first", "second", etc. in the specification and claims of the present disclosure and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so as to describe the embodiments of the present disclosure described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0047] In the present disclosure, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present disclosure and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0048] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this disclosure can be understood according to specific circumstances.

[0049] In addition, the terms "installed", "set", "provided with", "connected", "connected", and "socketed" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this disclosure can be understood according to specific circumstances.

[0050] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure may be combined with each other. The present disclosure will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0051] Example 1

[0052] See also Figures 1 to 3 This embodiment provides a preparation process for a half-cell solar cell, the preparation process at least comprising: sequentially performing a first laser operation, a coating operation, and a second laser operation. The first laser operation forms grooves 2 at both ends of the non-gridline region of the solar cell 1. The coating operation forms a passivation film 3 on the groove surface of the groove 2. The second laser operation splits the solar cell 1 into two parts along the region between the two grooves 2.

[0053] By dividing the grooving 2 and the splitting into two steps and inserting a coating operation between the two steps, the groove surface of the groove 2 is covered with a passivation film 3, thereby protecting the cutting morphology formed after the groove 2, reducing edge defects directly exposed to the air, reducing the number of dangling bonds, thereby reducing the formation of carrier recombination centers and improving the overall performance of the battery.

[0054] At the same time, since the solar cell 1 after the groove 2 is cut still maintains the whole structure, it is compatible with the existing preparation process and processing tooling of the whole solar cell 1, thereby avoiding the modification of the existing preparation process and processing tooling and reducing costs.

[0055] In addition, during the coating operation, the groove surface of the groove 2 can form a passivation film 3 synchronously with the front and / or back of the solar cell 1, so no coating layer that affects the appearance and performance is generated. This not only simplifies the production process, but also reduces the equipment investment cost, making the overall production more efficient and economical.

[0056] In detail, the second laser operation includes: forming a linear heating zone in the region of the solar cell 1 between the two grooves 2, and cooling the linear heating zone to split the solar cell 1 into two parts.

[0057] In this embodiment, a cleaning operation is also included, and the cleaning operation is performed to clean the groove surface of the groove 2. That is, the cleaning operation is arranged between the first laser operation and the coating operation to etch the groove surface of the groove 2, reduce the damage of the cutting surface, and help to enhance the adhesion of the subsequent passivation film 3, thereby improving the overall performance and stability of the film layer. Of course, in other embodiments, the cleaning operation can also be arranged before the first laser operation.

[0058] In some optional embodiments, the cleaning operation includes a PSG removal step.

[0059] In some alternative embodiments, the cleaning operation includes an RCA cleaning process.

[0060] In some further optional embodiments, the cleaning operation includes a PSG removal process and an RCA cleaning process performed sequentially.

[0061] In some embodiments, a protective layer plating operation may be further included to form a protective layer (not shown) on the surface of the passivation film 3 at least on the groove surface of the groove 2. The protective layer plating operation may be arranged between the film plating operation and the second laser operation, or may be arranged after the second laser operation, so as to avoid the influence of moisture, corrosive substances and external pollutants on the passivation film 3, maintain the functionality of the passivation film 3 and extend its service life. In detail, the protective layer is a layer or a plurality of layers selected from long-chain fatty alcohol, polyvinyl alcohol, polyacrylate, fluorinated polymer, silicon oxide, titanium oxide and zinc oxide.

[0062] It should be noted that the coating operation of the solar cell 1 includes at least one coating process of ALD deposition, positive film coating, and back film coating. The first laser operation is arranged before the coating operation, so that the passivation film 3 is formed under the action of one or more processes of ALD deposition, positive film coating, and back film coating.

[0063] In detail, the passivation film 3 includes one or more stacked layers of an aluminum oxide layer 31 , a silicon oxide layer 32 , a silicon nitride layer 33 , a silicon oxynitride layer 34 or an aluminum nitride layer.

[0064] Please combine Figure 2 In this embodiment, the passivation film 3 includes an aluminum oxide layer 31, a silicon oxide layer 32, a silicon nitride layer 33 and a silicon oxynitride layer 34 stacked in sequence from the groove surface of the groove 2. The present disclosure does not specifically limit the type of the passivation film 3. It is determined by the type and sequence of the process in the coating operation of the solar cell 1.

[0065] The front and back sides of the solar cell 1 have a first gridline region and a second gridline region, such as a TOPcon cell, or only the back side has a first gridline region and a second gridline region, such as a back contact cell. The present disclosure does not specifically limit the type of solar cell 1. The non-gridline region is located between the first gridline region and the second gridline region and extends from one side of the solar cell 1 to the other side along a first direction. The non-gridline region can have one, and one non-gridline region can divide the solar cell 1 into two half-pieces. The non-gridline region can also have multiple, and multiple non-gridline regions can divide the solar cell 1 into multiple sub-pieces.

[0066] The groove 2 extends from the edge of the solar cell 1 along the first direction and ends in the solar cell 1. The extension length of the groove 2 in the first direction is 1 mm to 10 mm. Specifically, the extension length of the groove 2 in the first direction can be 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, which is not specifically limited in the present disclosure.

[0067] Please combine Figure 3 In this embodiment, the groove 2 penetrates the solar cell 1 in the thickness direction of the solar cell 1 .

[0068] Example 2

[0069] This embodiment provides a process for preparing a half-cell solar cell, which is similar to the process for preparing a half-cell solar cell in Embodiment 1: the depth of the groove 2 is less than the thickness of the solar cell 1 .

[0070] Detailed, such as Figure 4 As shown, the groove 2 is formed by being recessed inward from the front side of the solar cell 1. The passivation film 3 is formed by one or more processes of ALD deposition, positive film coating, and protective film coating.

[0071] Example 3

[0072] This embodiment provides a process for preparing a half-cell solar cell, which is similar to the process for preparing a half-cell solar cell in Embodiment 1: the depth of the groove 2 is less than the thickness of the solar cell 1 .

[0073] Detailed, such as Figure 5 As shown, the groove 2 is formed by being recessed inward from the back side of the solar cell 1. The passivation film 3 is formed by one or more processes of ALD deposition, back film coating, and protective film coating.

[0074] Example 4

[0075] This embodiment provides a process for preparing a half-cell solar cell, which is similar to the process for preparing a half-cell solar cell in Embodiment 1: the depth of the groove 2 is less than the thickness of the solar cell 1 .

[0076] Detailed, such as Figure 6 As shown, the groove 2 is formed by being recessed inward from the front and back of the solar cell 1. The passivation film 3 on the groove surface of the groove 2 located on the front of the solar cell 1 is formed by one or more processes of ALD deposition, positive film coating, and protective film coating. The passivation film 3 on the groove surface of the groove 2 located on the back of the solar cell 1 is formed by one or more processes of ALD deposition, back film coating, and protective film coating.

[0077] Example 5

[0078] This embodiment provides a preparation process for a half-cell solar cell, where the half-cell solar cell is a half-cell TOPcon cell. Of course, in other embodiments, the half-cell solar cell may also be a half-cell back contact cell. The preparation process for one half-cell TOPcon cell is used as an example for description.

[0079] Please combine Figure 7 The preparation process in this embodiment is different from the preparation process in Example 1 in that it comprises the following steps:

[0080] Texturing: forming a velvet surface on the front side of the silicon wafer;

[0081] Boron diffusion: a boron-doped layer is formed on the front side of the silicon wafer, forming the emitter of the PN junction of the cell;

[0082] Oxidation: Push the junction again on the surface of the boron diffusion surface, and grow a BSG layer on the surface;

[0083] BSG removal: remove the BSG layer grown on the surface;

[0084] Alkali polishing: Alkali polishing is performed on the back side of the silicon wafer;

[0085] Phosphorus diffusion: forming a phosphorus-doped layer on the back side of the silicon wafer;

[0086] PSG removal: remove the PSG layer grown on the surface;

[0087] The first laser operation: forming grooves at both ends of the non-gridline area of ​​the solar cell;

[0088] RCA cleaning: remove the poly silicon plated on the front side of the silicon wafer and clean the grooves;

[0089] Coating operation: forming a passivation film on the front, back and groove surface of the silicon wafer;

[0090] Screen printing: metallization printing is performed on the front and back sides of the silicon wafer to form positive and negative electrodes;

[0091] LECO: Laser treatment of solar cells with external bias;

[0092] Test and sorting: test and sort the performance, EL and appearance of the battery cells;

[0093] The second laser operation: splits the solar cell into two parts along the area between the two grooves;

[0094] Packaging and assembly: Packaging half of the solar cell to achieve connection with the external circuit.

[0095] It should be noted that the structures of the grooves and the passivation film in this embodiment may also be the same as the structures of the grooves and the passivation film in Embodiment 2, Embodiment 3 or Embodiment 4.

[0096] Example 6

[0097] This embodiment provides a half-cell solar cell, which is manufactured by any one of the manufacturing processes of the half-cell solar cell in Embodiments 1 to 5.

[0098] In detail, a half-cell solar cell comprises a split section, and the split section comprises a first region 4 and second regions 5 located at both ends of the first region 4. The morphology of the first region 4 is different from that of the second region 5, and the surface of the second region 5 is covered with a passivation film (not shown), and the first region 4 does not have a passivation film.

[0099] The second region 5 is the groove surface of the groove. The passivation film on the surface of the second region 5 has the same structure as any one of the passivation films in Embodiments 1 to 4. For details, please refer to the above embodiments, which will not be described here.

[0100] like Figures 8 to 11As shown, the characteristics of the split cross-sections of the half-sheet solar cell formed after the splitting of the four solar cell sheets with different groove structures in Examples 1 to 4 are respectively shown. Among them, the width of the second region 5 along the thickness direction of the half-sheet solar cell is equal to or less than the thickness of the half-sheet solar cell. The second region 5 extends from the end of the split cross-section along the length direction of the split cross-section, and the length of the second region 5 is 1 mm to 10 mm.

[0101] It should be noted that the split section refers to the surface feature formed on each half of the solar cell after the solar cell is split into two half solar cells along the area between the two grooves. In this embodiment, the first area 4 is formed by a linear heating area in the area between the two grooves of the solar cell by the second laser operation, and then the linear heating area is cooled to achieve fracture, and the second area 5 is grooved on the solar cell by the first laser operation, so that the second area 5 has a laser ablation morphology, and the first area 4 has a mechanical fracture morphology.

[0102] As described above, since the second region 5 is formed by direct grooving through the first laser operation, and the first region 4 is formed by laser heating, cooling and splitting, the height of the second region 5 is lower than the height of the first region 4 in the direction perpendicular to the split section. In order to avoid the step seam caused by the height difference from generating a large number of dangling bonds and defect states, thereby forming a carrier recombination center to affect the photoelectric conversion efficiency of the solar cell. In this embodiment, the thickness of the passivation film is not less than the height difference between the second region 5 and the first region 4, so as to ensure that the passivation film can effectively cover the step seam.

[0103] Example 7

[0104] This embodiment provides a photovoltaic assembly including a plurality of half-cell solar cells, wherein the plurality of half-cell solar cells are connected in series to form a cell string, and the half-cell solar cell has the same structure as the half-cell solar cell in Embodiment 6.

[0105] Finally, it should be noted that the above are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A process for preparing a half-cell solar cell, characterized in that: At least the following steps are included: sequentially performing a first laser operation, a coating operation, and a second laser operation; Wherein, the first laser operation forms grooves at both ends of the non-gridline area of ​​the solar cell respectively; The coating operation forms a passivation film on the groove surface of the groove; The second laser operation splits the solar cell into two parts along the area between the two grooves.

2. The process for preparing a half-cell solar cell according to claim 1, characterized in that: The second laser operation comprises the following steps: Forming a linear heating zone in the region of the solar cell between the two grooves; The linear heating zone is cooled to split the solar cell into two parts.

3. The process for preparing a half-cell solar cell according to claim 1, characterized in that: The method also includes a cleaning operation, which is performed to clean the groove surface of the groove.

4. The process for preparing a half-cell solar cell according to any one of claims 1 to 3, characterized in that: The passivation film includes one or more stacked layers of an aluminum oxide layer, a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer or an aluminum nitride layer.

5. The process for preparing a half-cell solar cell according to any one of claims 1 to 3, characterized in that: The passivation film includes an aluminum oxide layer and a silicon nitride layer stacked in sequence; or, the passivation film includes an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer stacked in sequence.

6. The process for preparing a half-cell solar cell according to claim 1, characterized in that: The front and back sides of the solar cell have a first gridline region and a second gridline region at the same time or only the back side has a first gridline region, the non-gridline region is located between the first gridline region and the second gridline region, and the non-gridline region extends from one side of the solar cell to the other side along a first direction.

7. The process for preparing a half-cell solar cell according to claim 6, characterized in that: The groove extends from the edge of the solar cell along a first direction and ends inside the solar cell.

8. The process for preparing a half-cell solar cell according to claim 7, characterized in that: The extending length of the groove in the first direction is 1 mm to 10 mm, and the groove penetrates the solar cell in the thickness direction of the solar cell or has a depth less than the thickness of the solar cell.

9. A half-cell solar cell, characterized in that: The solar cell is manufactured by the manufacturing process of a half-cell solar cell according to any one of claims 1 to 8, wherein the half-cell solar cell comprises a split section, wherein the split section comprises a first region and second regions located at both ends of the first region; The morphology of the first region is different from the morphology of the second region; The surface of the second region is covered with a passivation film.

10. The half-cell solar cell according to claim 9, characterized in that: The first region does not have the passivation film.

11. The half-cell solar cell according to claim 9, characterized in that: The passivation film includes one or more stacked layers of an aluminum oxide layer, a silicon oxide layer, a silicon nitride layer, a silicon oxynitride layer or an aluminum nitride layer.

12. The half-cell solar cell according to claim 9, characterized in that: The passivation film includes an aluminum oxide layer and a silicon nitride layer stacked in sequence; or, the passivation film includes an aluminum oxide layer, a silicon nitride layer, a silicon oxynitride layer, and a silicon oxide layer stacked in sequence.

13. The half-cell solar cell according to claim 9, characterized in that: The width of the second region along the thickness direction of the half solar cell is equal to or less than the thickness of the half solar cell; the second region extends from the end of the dividing section along the length direction of the dividing section, and the length of the second region is 1mm to 10mm.

14. The half-cell solar cell according to claim 8, characterized in that: The second region has a laser ablated morphology and the first region has a mechanically fractured morphology.

15. A photovoltaic module, characterized in that The invention comprises a plurality of half-cell solar cells according to any one of claims 9 to 14, wherein the plurality of half-cell solar cells are connected in series to form a cell string.

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