Method for manufacturing a photovoltaic cell and device therefor, photovoltaic cell, photovoltaic module

Abstract

The present disclosure relates to the field of photovoltaics, and provides a manufacturing method of a photovoltaic cell, a device thereof, a photovoltaic cell and a photovoltaic module. The manufacturing method comprises: providing an initial cell piece, the initial cell piece comprising: a cell substrate; a first conductive part on the cell substrate; a passivation layer on at least a part of the first conductive part or on a part of the first conductive part; and welding a second conductive part on the passivation layer away from the first conductive part by using an ultrasonic welding process. The ultrasonic welding process comprises at least a first stage and a second stage, the ultrasonic power in the first stage is greater than that in the second stage, and the first stage is at least beneficial to improving the conductive performance between the first conductive part and the second conductive part.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a method and apparatus for manufacturing a photovoltaic cell, a photovoltaic cell, and a photovoltaic module. Background Technology

[0002] With the gradual depletion of fossil fuels, photovoltaic cells are becoming increasingly widely used as a new energy alternative. A photovoltaic cell is a device that converts solar energy into electrical energy. It utilizes the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy.

[0003] Current photovoltaic (PV) cells mainly include BC cells (Back Contact cells), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated emitter and real cell) cells, and HIT / HJT (Heterojunction Technology) cells. By employing different film layer configurations and corresponding manufacturing methods, the electrical performance of PV cells can be improved while reducing optical losses.

[0004] However, the electrical performance of current photovoltaic cells still needs further improvement. Summary of the Invention

[0005] This disclosure provides a method and apparatus for manufacturing a photovoltaic cell, a photovoltaic cell, and a photovoltaic module, which at least helps to improve the conductivity between the first conductive part and the second conductive part.

[0006] This disclosure provides a method for manufacturing a photovoltaic cell, comprising: providing an initial cell, the initial cell comprising: a cell substrate; a first conductive portion located on the cell substrate; a passivation layer located on at least a portion of the first conductive portion or on a portion of the first conductive portion; and welding a second conductive portion by an ultrasonic welding process on the side of the passivation layer away from the first conductive portion; wherein the ultrasonic welding process comprises at least a first stage and a second stage, the ultrasonic power of the first stage being greater than the ultrasonic power of the second stage.

[0007] Optionally, at least a portion of the passivation layer is removed during the ultrasonic welding process; and / or, a portion of the second conductive portion is embedded in the first conductive portion.

[0008] Optionally, the second conductive portion includes a body portion and a protrusion portion. The passivation layer covered by the second conductive portion is completely removed during the ultrasonic welding process. The body portion is in contact with the first conductive portion, and the protrusion portion is embedded in the first conductive portion.

[0009] Optionally, the second conductive portion includes a body portion and a protrusion portion, a portion of the passivation layer is removed during the ultrasonic welding process, the remaining passivation layer is located between the body portion and the first conductive portion, and the protrusion portion is also embedded in the passivation layer.

[0010] Optionally, the ratio of the ultrasonic power in the second stage to the ultrasonic power in the first stage is greater than or equal to 0.2 and less than 1.

[0011] Optionally, the ultrasonic power of the first stage is 15W~20W; and / or, the ultrasonic power of the second stage is 10W~20W.

[0012] Optionally, the welding temperature of the ultrasonic welding process is 200℃~300℃.

[0013] Optionally, the surface of the battery substrate having the first conductive portion includes a central region and an edge region surrounding the central region, the first conductive portion including edge pads located in the edge region, and the passivation layer being located on at least a portion of the edge pads on the side away from the battery substrate.

[0014] Optionally, the initial battery cell further includes: a central pad located in the central region; with the battery substrate as a reference plane, the top surface of the central pad away from the battery substrate is higher than the top surface of the edge pad away from the battery substrate.

[0015] Optionally, the surface of the battery substrate having the first conductive portion includes a central region and an edge region surrounding the central region. The first conductive portion includes a grid line on the battery substrate, and the passivation layer is located at least on the side of the grid line located in the edge region away from the battery substrate.

[0016] Optionally, the step of providing the initial battery cell includes: providing a whole battery cell; cutting the whole battery cell to obtain at least two initial battery cells; wherein the aspect ratio of the initial battery cell is 1.6 to 3.49.

[0017] Optionally, the step of providing the initial battery cell includes: providing a whole battery cell; cutting the whole battery cell to obtain at least two initial battery cells; wherein the initial battery cell includes at least one cut surface, the edge region near the cut surface has a cut edge, the distance between the edge pad and the cut edge is a first distance, the distance between the passivation layer and the cut edge is a second distance, and the first distance is less than or equal to the second distance.

[0018] Optionally, the first spacing is 2mm to 4mm.

[0019] This disclosure also provides a photovoltaic cell manufacturing apparatus for implementing the photovoltaic cell manufacturing method as described in any of the preceding claims. The photovoltaic cell manufacturing apparatus includes: a conveying module for providing the initial cell; an ultrasonic welding module for welding a second conductive portion onto the initial cell; the ultrasonic welding module includes a control unit for setting process parameters of the ultrasonic welding module such that the ultrasonic welding process includes at least a first stage and a second stage, wherein the ultrasonic power of the first stage is greater than the ultrasonic power of the second stage.

[0020] This disclosure also provides a photovoltaic cell, comprising: an initial cell, the initial cell comprising: a cell substrate; a first conductive portion located on the cell substrate; a second conductive portion, at least a portion of the second conductive portion being located on the side of the first conductive portion away from the cell substrate, the second conductive portion comprising a body portion and a protrusion portion; wherein the body portion is in contact with the first conductive portion, and the protrusion portion is embedded in the first conductive portion; or, the photovoltaic cell further comprises a passivation layer located between the body portion and the first conductive portion, wherein the protrusion portion penetrates the passivation layer and is embedded in the first conductive portion along a first direction; the first direction is the thickness direction of the cell substrate.

[0021] Optionally, the thickness of the passivation layer along the first direction is 40nm~50nm.

[0022] Optionally, the thickness of the body portion along the first direction is 10μm to 15μm.

[0023] Optionally, along the first direction, the ratio of the embedding depth of the protrusion in the first conductive portion to the thickness of the first conductive portion is greater than or equal to 50% and less than 100%.

[0024] Optionally, the ratio of the projected area of ​​the protrusion on the battery substrate to the projected area of ​​the first conductive portion on the battery substrate is a first ratio, wherein the first ratio is greater than or equal to 50% and less than 100%.

[0025] This disclosure also provides a photovoltaic module, comprising: a battery string, which is formed by connecting a plurality of photovoltaic cells formed by the manufacturing method of photovoltaic cells as described in any of the above claims, or by connecting a plurality of photovoltaic cells formed by the manufacturing apparatus of photovoltaic cells as described in any of the above claims, or by connecting a plurality of photovoltaic cells as described in any of the above claims; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film opposite to the surface of the battery string.

[0026] The technical solution provided in this disclosure has at least the following advantages:

[0027] First, a first stage with higher ultrasonic power is used to break or remove at least part of the passivation layer through mechanical vibration or the generated shock wave, at least causing pores in the passivation layer or at least the removal of at least part of the passivation layer, thereby promoting direct contact and connection between the second conductive part and the first conductive part. Moreover, the higher ultrasonic power in the first stage can increase the area of ​​the first conductive part exposed by the passivation layer, thereby increasing the contact area between the second conductive part and the first conductive part. Subsequently, a second stage with lower ultrasonic power is used to further embed the second conductive part into the first conductive part, further increasing the contact area between the second conductive part and the first conductive part, and also increasing the connection strength between the second conductive part and the first conductive part. Thus, the conductivity between the second conductive part and the first conductive part can be improved from both the aspects of structural stability and contact area. Attached Figure Description

[0028] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A process flow diagram of a method for manufacturing a photovoltaic cell according to an embodiment of this disclosure;

[0030] Figure 2 This is a schematic diagram of a first partial top view of a photovoltaic cell manufacturing method provided in an embodiment of the present disclosure after the passivation layer has been formed;

[0031] Figure 3 for Figure 2 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1.

[0032] Figure 4 This is a third partial top view of the structure after welding the first conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure.

[0033] Figure 5 for Figure 4 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1.

[0034] Figure 6 for Figure 4 The diagram shows another partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1.

[0035] Figure 7 This is a second partial top view of the structure after the passivation layer is formed in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure.

[0036] Figure 8 for Figure 7 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the second cross-section direction BB1.

[0037] Figure 9 This is a second partial top view of the structure after welding the first conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure.

[0038] Figure 10 for Figure 9 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the second cross-section direction BB1.

[0039] Figure 11 for Figure 9 The diagram shows another partial cross-sectional structure of the photovoltaic cell along the two-section direction BB1.

[0040] Figure 12 This is a third partial top view of the structure after welding the second conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure.

[0041] Figure 13 for Figure 12 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the third section direction CC1.

[0042] Figure 14 This is a top view of a complete cell structure provided in a photovoltaic cell manufacturing method according to an embodiment of the present disclosure;

[0043] Figure 15 A schematic diagram of a functional module of a photovoltaic cell manufacturing apparatus provided in another embodiment of this disclosure;

[0044] Figure 16A partial three-dimensional structural diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure;

[0045] Figure 17 This is a partial cross-sectional structural diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0046] Explanation of reference numerals in the attached figures:

[0047] 10. Complete battery cell; 100. Initial battery cell; 110. Cut surface; 101. Battery substrate; 111. Central region; 121. Edge region; 1211. Cut edge; 102. First conductive part; 112. Edge pad; 122. Grid line; 103. Passivation layer; 113. Pore; 104. Second conductive part; 114. Body part; 124. Protrusion; 105. Central pad; 106. Conveying module; 107. Ultrasonic welding module; 117. Control unit; 40. Photovoltaic cell; 41. Encapsulating film; 42. Cover plate; 43. Welding strip. Detailed Implementation

[0048] As can be seen from the background technology, the electrical performance of photovoltaic cells needs to be further improved.

[0049] This disclosure provides a method and apparatus for manufacturing a photovoltaic cell, a photovoltaic cell, and a photovoltaic module. In the manufacturing method, a first stage with higher ultrasonic power is used to break or remove at least a portion of the passivation layer through mechanical vibration or generated shock waves. This results in at least pores appearing in the passivation layer or at least partial removal of the passivation layer, thereby promoting direct contact between the second conductive part and the first conductive part. Furthermore, the higher ultrasonic power in the first stage increases the area of ​​the first conductive part exposed by the passivation layer, thus increasing the contact area between the second and first conductive parts. Subsequently, a second stage with lower ultrasonic power further embeds the second conductive part into the first conductive part, further increasing the contact area and the connection strength between them. This improves the conductivity between the second and first conductive parts in terms of both structural stability and contact area.

[0050] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "multiple" means two or more (including two), unless otherwise explicitly defined. Similarly, "multiple sets" refers to two or more sets (including two sets), and "multiple pieces" refers to two or more pieces (including two pieces).

[0051] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0052] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0053] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of this disclosure and simplifying the description. They 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, and therefore should not be construed as a limitation on the embodiments of this disclosure. For example, if the device or element in the illustration is inverted, then the element described as "below," "under," "below," or "bottom" of other elements or features will be oriented "above" or "top" of said other elements or features. Therefore, the term "below" may, depending on the context in which the term is used, encompass both above and below orientations, which will be obvious to those skilled in the art. Materials may be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein may be interpreted accordingly.

[0054] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0055] In the description of the embodiments of this disclosure, electrical connection between one component and another means that both components are made of conductive materials, and the two components are in direct contact and connected or connected via other conductive materials. Therefore, when the photovoltaic module is generating electricity, current flows between the two components. Electrical contact between one component and another means that the two components are not only in contact, but also, because both components are made of conductive materials, current flows between the two components when the photovoltaic module is generating electricity.

[0056] In the description of embodiments of this disclosure, the terms "about," "approximately," "roughly," or "about" for a numerical value referring to a specific parameter include the numerical value, and those skilled in the art will understand that the deviation from the numerical value is within acceptable tolerances of the specific parameter. For example, "about" or "about" for a numerical value may include additional numerical values ​​that are in the range of 90.0% to 110.0% of the numerical value, such as in the range of 95.0% to 105.0%, 97.5% to 102.5%, 99.0% to 101.0%, 99.5% to 100.5%, or 99.9% to 100.1%.

[0057] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and / or area of ​​layers, films, panels, regions, etc., are enlarged for better understanding and ease of description. Throughout the specification, the same reference numerals denote the same elements. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a portion of the edge of the entire surface.

[0058] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. When a component (such as a layer, film, region, or substrate) is described as being on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be an intermediate component between the two components. Conversely, when a component is described as being on the surface of another component, or a component is "directly" on another component, or another component is formed or disposed on the surface of a component, it indicates that there is no intermediate component between the two components. For simplicity and clarity, various components may be drawn at any scale. In the drawings, some components may be omitted for simplicity.

[0059] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "the component" is also intended to include the plural form unless the context clearly indicates otherwise.

[0060] The “components” mentioned above can refer to layers, films, regions, parts, structures, etc.

[0061] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0062] This disclosure provides a method for manufacturing a photovoltaic cell according to an embodiment. The method for manufacturing a photovoltaic cell according to an embodiment of this disclosure will be described in detail below with reference to the accompanying drawings.

[0063] Reference Figures 1 to 6 or in conjunction with references Figure 1 and Figures 7 to 11 , Figure 1 This is a process flow diagram of a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure. The method for manufacturing a photovoltaic cell includes at least the following steps:

[0064] S1: Refer to Figure 2 and Figure 3 or in conjunction with references Figure 7 and Figure 8 An initial battery cell 100 is provided, the initial battery cell 100 including: a battery substrate 101; a first conductive portion 102 located on the battery substrate 101; and a passivation layer 103 located on at least a portion of the first conductive portion 102 or on a portion of the first conductive portion 102.

[0065] It should be noted that, depending on the different uses of the first conductive portion 102 in the initial battery cell 100, the positional relationship between the first conductive portion 102 and the battery substrate 101 will vary, thus affecting the positional relationship between the passivation layer 103 and the second conductive portion 104. The following will provide detailed explanations, in conjunction with embodiments, of "the passivation layer 103 is located on at least a portion of the first conductive portions 102" and "the passivation layer 103 is located on a portion of the first conductive portion 102." Figure 2 and Figure 3 The passivation layer 103 is shown to be located on at least a portion of the first conductive portion 102; Figure 7 and Figure 8The passivation layer 103 is shown to be located on a portion of the first conductive portion 102.

[0066] S2: Refer to Figure 4 Zhihe Figure 6 or in conjunction with references Figures 9 to 11 An ultrasonic welding process is used to weld the second conductive part 104 on the side of the passivation layer 103 away from the first conductive part 102; wherein the ultrasonic welding process includes at least a first stage and a second stage, and the ultrasonic power of the first stage is greater than the ultrasonic power of the second stage.

[0067] It is worth noting that ultrasonic welding primarily achieves the connection between two components through high-frequency mechanical vibration rather than simply high temperature. Furthermore, in traditional welding processes, excessively high welding temperatures can easily decompose and damage the formed film, leading to performance degradation. Traditional welding also requires the assistance of chemical flux to achieve the connection between the two components, and the residue of this chemical flux can also affect the connection performance. Therefore, ultrasonic welding offers lower and more controllable welding temperatures, which helps reduce thermal damage to the initial solar cell 100. Moreover, it eliminates the need for additional flux, thus preventing flux contamination of the initial solar cell 100 from the outset.

[0068] Based on the above, to improve the conductivity between the first conductive part 102 and the second conductive part 104, the ultrasonic welding process is designed to include at least a first stage and a second stage, with the ultrasonic power of the first stage being greater than that of the second stage. Thus, the first stage, with its higher ultrasonic power, uses higher-frequency mechanical vibration or generated shock waves to break through part of the passivation layer 103, or in other words, to shatter and remove part of the passivation layer 103, at least creating pores in the passivation layer 103 or removing at least part of it. This allows the second conductive part 104 to penetrate the passivation layer 103 and directly contact the first conductive part 102, ensuring the contact connection between the first conductive part 102 and the second conductive part 104. Furthermore, the higher ultrasonic power in the first stage increases the exposure of the passivation layer 103. The area of ​​the first conductive part 102 is increased, thereby increasing the contact area between the second conductive part 104 and the first conductive part 102. Subsequently, with the help of a second stage with lower ultrasonic power, the second conductive part 104 is further embedded in the first conductive part 102 to further increase the contact area between the second conductive part 104 and the first conductive part 102, and can also improve the connection strength between the second conductive part 104 and the first conductive part 102. Thus, the conductivity between the second conductive part 104 and the first conductive part 102 can be improved from both structural stability and contact area perspectives.

[0069] It should be noted that the direction of the interface between the first conductive part 102 and the passivation layer 103 is generally considered to be horizontal, and the direction of the first conductive part 102 pointing to the passivation layer 103 is generally considered to be vertical. In the first stage with higher ultrasonic power, more second conductive parts 104 can penetrate the passivation layer 103 to the first conductive part 102, thereby increasing the contact area between the second conductive part 104 and the first conductive part 102 in the horizontal direction. In the second stage with lower ultrasonic power, more second conductive parts 104 that have penetrated the passivation layer 103 can be embedded in the first conductive part 102, thereby increasing the contact area between the second conductive part 104 and the first conductive part 102 in the vertical direction.

[0070] In some embodiments, the low welding temperature of the ultrasonic welding process makes it advantageous to design the initial solar cell 100 as a perovskite solar cell with poor heat resistance, thereby making the photovoltaic cell manufacturing method provided in one embodiment of this disclosure applicable to more types of photovoltaic cells.

[0071] In some embodiments, photovoltaic cells include, but are not limited to, one or any combination of PERC cells, BC cells, TOPCON cells, HIT / HJT cells, thin-film solar cells, and tandem cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0072] Among them, BC batteries include, but are not limited to, IBC batteries (Interdigitated Back Contact), HBC batteries (Heterojunction Back Contact), TBC batteries (TOPCon Back Contact), HTBC batteries (Heterojunction TunnelOxide Passivated Back Contact), or HPBC batteries (Hybrid Passivated Back Contact).

[0073] In some embodiments, the photovoltaic cell can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-component compound solar cell. Specifically, the multi-component compound solar cell can be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell, or a perovskite solar cell.

[0074] in, Figure 2 This is a schematic diagram of a first partial top view of a photovoltaic cell manufacturing method provided in an embodiment of the present disclosure after the passivation layer has been formed; Figure 3 for Figure 2 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1. Figure 4 This is a third partial top view of the structure after welding the first conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure. Figure 5 for Figure 4 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1. Figure 6 for Figure 4 The diagram shows another partial cross-sectional structure of the photovoltaic cell along the first cross-section direction AA1. Figure 7 This is a second partial top view of the structure after the passivation layer is formed in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure. Figure 8 for Figure 7 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the second cross-section direction BB1. Figure 9 This is a second partial top view of the structure after welding the first conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure. Figure 10 for Figure 9 The diagram shows a partial cross-sectional structure of the photovoltaic cell along the second cross-section direction BB1. Figure 11 for Figure 9 The diagram shows another partial cross-sectional structure of the photovoltaic cell along the two-section direction BB1.

[0075] It should be noted that, Figure 2 , Figure 4 , Figure 7 and Figure 9 The passivation layer 103 is drawn using a perspective drawing method to show the positional relationship between the passivation layer 103 and other film layers.

[0076] The photovoltaic cell provided in one embodiment of this disclosure will be described in more detail below with reference to the accompanying drawings.

[0077] In some embodiments, reference Figure 5 , Figure 6 , Figure 10 or Figure 11 At least part of the passivation layer 103 is removed during the ultrasonic welding process.

[0078] In general, during ultrasonic welding, the second conductive part 104 is welded to the first conductive part 102 from the side of the passivation layer 103 away from the first conductive part 102 using a welding head. During this process, on the one hand, the molten second conductive part 104 is prone to generating voids or bubbles. When the second conductive part 104 comes into contact with the passivation layer 103, the shock wave generated by the implosion of the voids or bubbles can break the passivation layer 103, thus achieving contact connection between the first conductive part 102 and the second conductive part 104. On the other hand, when the second conductive part 104 comes into contact with the passivation layer 103, the welding head also exerts a squeezing effect on the passivation layer 103, causing the passivation layer 103 to break and be removed.

[0079] Based on this, for the portion of the passivation layer 103 that will subsequently come into contact with the second conductive portion 104, or for the portion of the passivation layer 103 covered by the second conductive portion 104 before the ultrasonic welding process, at least the following two situations exist during the ultrasonic welding process: In some cases, refer to Figure 5 or Figure 10 The passivation layer 103 has pores 113 in the portion covered by the second conductive portion 104. The second conductive portion 104 is located in the pores 113 and thus contacts and connects with the first conductive portion 102. In other words, a passivation layer 103 is also present between a portion of the second conductive portion 104 and the first conductive portion 102. In other cases, refer to Figure 6 or Figure 11 The portion of the passivation layer 103 covered by the second conductive portion 104 is removed, and the entire second conductive portion 104 and the first conductive portion 102 are in contact and connected. In other words, there is no passivation layer between the second conductive portion 104 and the first conductive portion 102.

[0080] In some embodiments, reference Figure 5 , Figure 6 , Figure 10 or Figure 11 A portion of the second conductive part 104 is embedded in the first conductive part 102. In this way, the second conductive part 104 not only contacts the surface of the first conductive part 102, but also penetrates deep into the first conductive part 102. This not only further increases the contact area between the second conductive part 104 and the first conductive part 102, but also enhances the connection strength between the second conductive part 104 and the first conductive part 102 through embedding.

[0081] It should be noted that, regardless of... Figure 5 or Figure 10 A passivation layer 103 is spaced between a portion of the second conductive portion 104 and the first conductive portion 102, as shown. Figure 6 or Figure 11There is no passivation layer between the second conductive part 104 and the first conductive part 102. Parts of the second conductive part 104 can be embedded in the first conductive part 102. The embedding of the second conductive part 104 will be described in detail below.

[0082] In some embodiments, reference Figure 6 or Figure 11 The second conductive part 104 may include a body part 114 and a protrusion 124. The passivation layer 103 covered by the second conductive part 104 is completely removed in the ultrasonic welding process. The body part 114 is in contact with the first conductive part 102, and the protrusion 124 is embedded in the first conductive part 102. That is, there is no passivation layer between the second conductive part 104 and the first conductive part 102.

[0083] It should be noted that, Figure 6 and Figure 11 The body portion 114 and the protrusion portion 124 are divided in the second conductive portion 104 by a dashed line.

[0084] In some cases, refer to Figure 2 or Figure 7 The passivation layer 103 is also located in the interval between adjacent first conductive parts 102. During the ultrasonic welding process, the second conductive part 104 will not be welded on the passivation layer 103 located in the interval between adjacent first conductive parts 102. Therefore, the passivation layer 103 located in the interval between adjacent first conductive parts 102 will be retained to passivate the battery substrate 101.

[0085] In other embodiments, reference is made to... Figure 5 or Figure 10 The second conductive portion 104 may include a body portion 114 and a protrusion 124. Part of the passivation layer 103 is removed during the ultrasonic welding process, and the remaining passivation layer 103 is located between the body portion 114 and the first conductive portion 102. The protrusion 124 is also embedded in the passivation layer 103. In other words, along the first direction X, the passivation layer 103 may include a portion to be welded, which has a pore 113 formed after part of the passivation layer 103 is removed during the ultrasonic welding process. Without considering the influence of the pore 113, the orthographic projection of the portion to be welded on the battery substrate 101 coincides with the orthographic projection of the second conductive portion 104 on the battery substrate 101. The protrusion 124 is located in the pore 113 and further embedded in the first conductive portion 102. The first direction X is the thickness direction of the battery substrate 101.

[0086] It should be noted that, Figure 5 and Figure 10 The body portion 114 and the protrusion portion 124 are divided in the second conductive portion 104 by a dashed line.

[0087] The relevant process parameters used in ultrasonic welding are explained in detail below.

[0088] In some embodiments, the ratio of the ultrasonic power of the second stage to the ultrasonic power of the first stage may be greater than or equal to 0.2 and less than 1. For example, the ratio of the ultrasonic power of the second stage to the ultrasonic power of the first stage may be greater than or equal to 0.2 and less than 0.5, or the ratio of the ultrasonic power of the second stage to the ultrasonic power of the first stage may be greater than or equal to 0.5 and less than 0.8, or the ratio of the ultrasonic power of the second stage to the ultrasonic power of the first stage may be greater than or equal to 0.8 and less than 1.

[0089] Optionally, the ratio of the ultrasonic power in the second stage to the ultrasonic power in the first stage can be 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, or 0.95, etc.

[0090] It is worth noting that, in conjunction with references Figures 4 to 6 or in conjunction with references Figures 9 to 11 During the ultrasonic welding process, the first stage is mainly used to make less area of ​​the first conductive part 102 covered by the passivation layer 103 so that the second conductive part 104 can contact and connect with more of the first conductive part 102; the second stage is mainly used to promote the second conductive part 104 to melt into the interior of the first conductive part 102, so that more area of ​​the second conductive part 104 is embedded in the first conductive part 102, and to avoid mechanical damage to the first conductive part 102, and to prevent the second conductive part 104 from penetrating the first conductive part 102 along the first direction X.

[0091] Based on this, if the ratio of the ultrasonic power in the second stage to the ultrasonic power in the first stage is less than 0.2, on the one hand, even if the first stage has a large impact force on the passivation layer 103 to remove part of the passivation layer 103, the smaller ultrasonic power in the second stage is not conducive to causing more of the second conductive parts 104 to melt into the interior of the first conductive part 102. On the other hand, if it is ensured that more of the second conductive parts 104 melt into the interior of the first conductive part 102 in the second stage, the excessive ultrasonic power in the first stage will cause the first conductive part 102 to be mechanically damaged in the first stage. If the ratio of the ultrasonic power in the second stage to the ultrasonic power in the first stage is greater than or equal to 1, while ensuring that the first stage has a large impact force on the passivation layer 103 to remove part of the passivation layer 103, it is not conducive to avoiding mechanical damage to the first conductive part 102 in the second stage, nor is it conducive to avoiding the second conductive part 104 penetrating the first conductive part 102 along the first direction X in the second stage.

[0092] Therefore, designing the ratio of the ultrasonic power of the second stage to that of the first stage to be greater than or equal to 0.2 and less than 1 is beneficial to ensure that the first and second stages can each perform their respective functions. This ensures that a smaller area of ​​the first conductive part 102 is covered by the passivation layer 103, so that the second conductive part 104 can make contact and connect with more of the first conductive part 102. It also ensures that a larger area of ​​the second conductive part 104 is embedded in the first conductive part 102, and avoids mechanical damage to the first conductive part 102, as well as prevents the second conductive part 104 from penetrating the first conductive part 102 along the first direction X.

[0093] In some embodiments, the ultrasonic power of the first stage can be 15W to 25W. For example, the ultrasonic power of the first stage can be 15W to 20W, or the ultrasonic power of the first stage can be 20W to 25W.

[0094] Optionally, the ultrasonic power of the first stage can be 15W, 16W, 17W, 18W, 19W, 20W, 21W, 22W, 23W, 24W or 25W, etc.

[0095] It is worth noting that, in conjunction with references Figures 4 to 6 or in conjunction with references Figures 9 to 11 In the ultrasonic welding process, the first stage is mainly used to remove at least part of the passivation layer 103, or to expose more of the first conductive part 102 in the remaining passivation layer 103, so that the second conductive part 104 can contact and connect with the first conductive part 102. When welding the second conductive part 104 using ultrasonic welding on the side of the passivation layer 103 away from the first conductive part 102, if the ultrasonic power is too low, it is difficult to form a gap 113 in the passivation layer 103 to expose the first conductive part 102, which may cause the second conductive part 104 to be completely blocked by the passivation layer 103 and unable to contact and connect with the first conductive part 102. If the ultrasonic power is too high, in addition to causing the passivation layer 103 to break, it may also cause mechanical damage to the first conductive part 102.

[0096] Based on this, the ultrasonic power of the first stage is designed to be 15W~25W. On the one hand, this is beneficial to maximize the ultrasonic power of the first stage to increase the impact force on the passivation layer 103, so that the passivation layer 103 can expose more of the first conductive part 102, thereby increasing the contact area between the first conductive part 102 and the second conductive part 104. On the other hand, while removing part of the passivation layer 103, mechanical damage to the first conductive part 102 is avoided, so as to ensure that the first conductive part 102 itself has good conductivity.

[0097] In some embodiments, the ultrasonic power of the second stage can be 5W to 20W. For example, the ultrasonic power of the second stage can be 5W to 10W, or the ultrasonic power of the second stage can be 10W to 20W.

[0098] Optionally, the ultrasonic power of the second stage can be 5W, 6W, 7W, 8W, 9W, 10W, 11W, 12W, 13W, 14W, 15W, 16W, 17W, 18W, 19W, or 20W, etc.

[0099] It is worth noting that, in conjunction with references Figure 4 Zhihe Figure 6 or in conjunction with references Figures 9 to 11 During the ultrasonic welding process, after the second conductive part 104 can penetrate the passivation layer 103 to contact the first conductive part 102, the second stage is mainly used to promote the melting of the second conductive part 104 into the interior of the first conductive part 102. This allows local areas of the second conductive part 104 and local areas of the first conductive part 102 to melt and recrystallize into a whole, thereby further reducing the contact resistance between the second conductive part 104 and the first conductive part 102 and improving their connection strength, reducing the risk of the second conductive part 104 detaching. Therefore, in the second stage, it is not necessary to provide a large impact force to the passivation layer 103; it is only necessary to promote the melting of the second conductive part 104 into the interior of the first conductive part 102, and the second conductive part 104 does not need to penetrate the entire thickness of the first conductive part 102.

[0100] Based on this, the ultrasonic power of the second stage is designed to be 5W~20W. On the one hand, this is beneficial to promote the melting of more of the second conductive part 104 into the interior of the first conductive part 102, thereby increasing the contact area between the second conductive part 104 and the first conductive part 102. On the other hand, it avoids the second conductive part 104 from penetrating the first conductive part 102 to make contact with the battery substrate 101 due to a large power density, so as to avoid bringing additional interface defects to the interface between the first conductive part 102 and the battery substrate 101 and reduce the risk of carrier recombination.

[0101] In some embodiments, the welding temperature of the ultrasonic welding process can be 200℃~300℃, for example, 200℃~250℃ or 250℃~300℃.

[0102] Optionally, the welding temperature of the ultrasonic welding process can be 200℃, 210℃, 220℃, 230℃, 240℃, 250℃, 260℃, 270℃, 280℃, 290℃ or 300℃, etc.

[0103] It is evident that, compared to traditional welding processes where the welding temperature is generally above 400℃, ultrasonic welding at 200℃~300℃ is beneficial in reducing the impact on the entire initial solar cell (reference 100). Figure 2 The thermal effects of ).

[0104] The following describes in detail the function of the first conductive part 102 in the initial battery cell 100.

[0105] In some embodiments, in conjunction with reference Figures 2 to 6 The surface of the battery substrate 101, which is provided with the first conductive portion 102, includes a central region 111 and an edge region 121 surrounding the central region 111. The first conductive portion 102 may include edge pads 112 located in the edge region 121. The passivation layer 103 is located on at least a portion of the edge pads 112 on the side away from the battery substrate 101.

[0106] It is worth noting that during the manufacturing process of photovoltaic cells, the edge pads 112 located in the edge region 121 are more susceptible to various manufacturing processes than the central region 111. In particular, the passivation layer 103 plated around the edge can easily cover the side of the edge pads 112 away from the cell substrate 101, which means that the edge pads 112 that originally needed to be electrically connected to the solder ribbon are isolated by the passivation layer 103, affecting the further collection of charge carriers collected by the solder ribbon on the edge pads 112.

[0107] Based on this, refer to Figures 4 to 6 An ultrasonic welding process is used to weld the second conductive part 104 on the side of the passivation layer 103 away from the edge pad 112. This process helps to remove the influence of the passivation layer 103 on the edge pad 112 by using the ultrasonic welding process and the cooperation of the second conductive part 104. The carrier transmission channel is opened through the contact connection between the second conductive part 104 and the edge pad 112. The subsequent electrical connection between the solder strip and the second conductive part 104 can further collect the carriers collected by the edge pad 112.

[0108] In some cases, continue to refer to Figure 2 The passivation layer 103 is located not only on a portion of the edge pads 112 away from the battery substrate 101, but also in the intervals between adjacent edge pads 112.

[0109] In some cases, refer to Figure 12 and Figure 13 The initial battery cell 100 may further include: a central pad 105 located in the central region 111; with the battery substrate 101 as the reference plane, the top surface of the central pad 105 away from the battery substrate 101 is higher than the top surface of the edge pad 112 away from the battery substrate 101.

[0110] in, Figure 12This is a third partial top view of the structure after welding the second conductive part in a method for manufacturing a photovoltaic cell according to an embodiment of the present disclosure. Figure 13 for Figure 12 The diagram shows a partial cross-sectional view of the photovoltaic cell along the third section direction CC1. It should be noted that... Figure 12 The passivation layer 103 is drawn using a perspective drawing method to show the positional relationship between the passivation layer 103 and other film layers; Figure 13 The body portion 114 and the protrusion portion 124 are divided in the second conductive portion 104 by a dashed line.

[0111] It is worth noting that on the edge region 121, at least a second conductive portion 104 is stacked on the first conductive portion 102 along the first direction X. Figure 5 In the example shown, a passivation layer 103 and a second conductive portion 104 are stacked on the first conductive portion 102 along the first direction X. Thus, when the solder ribbon is electrically connected to the second conductive portion 104, the edge region 121 is raised. Based on this, the top surface of the center pad 105 away from the battery substrate 101 is designed to be higher than the top surface of the edge pad 112 away from the battery substrate 101. This allows the solder ribbon to be raised in the center region 111 by utilizing the height difference between the center pad 105 and the edge pad 112. In other words, the height difference between the center pad 105 and the edge pad 112 compensates for the thickness of the second conductive portion 104 added to the edge pad 112, reducing the height difference between the portion of the solder ribbon in the center region and the portion in the edge region. This reduces the degree of bending of the solder ribbon, thereby avoiding excessive compression of the initial battery cell 100 by the solder ribbon and reducing the risk of breakage of the initial battery cell 100 in subsequent processes.

[0112] In some examples, reference Figure 13 With the battery substrate 101 as the reference plane, the height difference H between the top surface of the center pad 105 away from the battery substrate 101 and the top surface of the edge pad 112 away from the battery substrate 101 can be 10μm~15μm, for example, it can be 10μm~11μm, 11μm~12μm, 12μm~13μm, 13μm~14μm or 14μm~15μm, etc.

[0113] Optionally, the height difference H between the top surface of the center pad 105 away from the battery substrate 101 and the top surface of the edge pad 112 away from the battery substrate 101 can be 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm or 15μm, etc.

[0114] In some cases, in conjunction with references Figure 14 and Figure 2The step of providing an initial battery cell 100 may include: providing a whole battery cell 10; cutting the whole battery cell 10 to obtain at least two initial battery cells 100; wherein the initial battery cell 100 includes at least one cut surface 110, an edge region 121 near the cut surface 110 has a cut edge 1211, the distance between the edge pad 112 and the cut edge 1211 is a first distance D1, the distance between the passivation layer 103 and the cut edge 1211 is a second distance D2, and the first distance D1 is less than or equal to the second distance D2.

[0115] in, Figure 14 This is a top view schematic diagram of a complete photovoltaic cell provided in a method for manufacturing a photovoltaic cell according to an embodiment of this disclosure. Figure 14 The cutting lines in the entire battery 10 are divided by dashed lines, and Figure 14 Taking the example of a single whole cell 10 being cut into two initial cell pieces 100, in actual applications, there is no limit to the number of initial cell pieces cut from a single whole cell; for example, it can also be three, four, or five, etc.

[0116] It should be noted that, along the direction from the edge area 121 to the center area 111, the distance between the edge pad 112 and the cutting edge 1211, i.e., the first distance D1, refers to the distance between the edge pad 112 and the cutting edge 1211, which is the closest contour to the cutting edge 1211; the distance between the passivation layer 103 and the cutting edge 1211, i.e., the second distance D2, refers to the distance between the passivation layer 103 and the cutting edge 1211, which is the furthest contour from the cutting edge 1211.

[0117] It is worth noting that, in order to reduce cutting damage to the cut surface 110, a passivation layer 103 is usually formed on the cut surface 110. In the step of forming the passivation layer 103, the passivation layer 103 is plated around the edge pad 112. However, in conventional processes, in order to avoid the passivation layer being plated around the edge pad, the edge pad is set in a region closer to the center region of the edge area or directly set in the center region. This is not conducive to the collection of carriers generated in the part of the battery substrate located in the edge region; or, in order to avoid the passivation layer being plated around the edge pad, the width of the passivation layer plated around the edge region is limited to be too large. This limits the process window for forming the passivation layer.

[0118] However, in the photovoltaic cell manufacturing method provided in one embodiment of this disclosure, by utilizing the ultrasonic welding process and the cooperation of the second conductive part 104, not only can the poor electrical connection between the subsequent solder strip and the initial cell 100 caused by the passivation layer 103 covering the first conductive part 102 be avoided, but the edge pad 112 can also be located in the edge region 121 closer to the cutting edge 1211, which is beneficial to improving the collection efficiency of the edge pad 112 for the carriers generated in the portion of the cell substrate 101 located in the edge region 121. In addition, in the direction from the edge region 121 to the center region 111, there is no need to limit the width of the passivation layer 103 deposited around the edge region 121, which is beneficial to increase the process window for forming the passivation layer 103, and thus more conducive to forming a passivation layer 103 with high film quality.

[0119] In some examples, the first spacing D1 can be 2mm to 4mm, for example, 2mm to 3mm or 3mm to 4mm. Optionally, the first spacing D1 can be 2mm, 2.1mm, 2.2mm, 2.3mm, 2.4mm, 2.5mm, 2.6mm, 2.7mm, 2.8mm, 2.9mm, 3mm, 3.1mm, 3.2mm, 3.3mm, 3.4mm, 3.5mm, 3.6mm, 3.7mm, 3.8mm, 3.9mm or 4mm.

[0120] It is worth noting that in conventional processes, to avoid the passivation layer being plated around the edge pads, the width of the passivation layer plated around the edge area is generally limited to at least 3 mm in the direction from the edge area to the center area, or the edge pads are placed in an area at least 3 mm away from the cutting edge. However, in the photovoltaic cell manufacturing method provided in an embodiment of this disclosure, by means of ultrasonic welding process and the cooperation of the second conductive part 104, the "3 mm" limitation can be broken. That is, in the direction from the edge area 121 to the center area 111, it is not necessary to limit the width of the passivation layer 103 plated around the edge area 121, thus increasing the process window for forming the passivation layer 103. At the same time, the edge pads 112 can be placed in an area within 3 mm of the cutting edge 1211, thereby improving the collection efficiency of the edge pads 112 for the portion of the cell substrate 101 located in the edge area 121. Furthermore, on the one hand, designing the spacing between the edge pad 112 and the cutting edge 1211, i.e., the first spacing D1 being greater than or equal to 2mm, can prevent the edge pad 112 from being too close to the cutting edge 1211, thereby preventing the solder ribbon subsequently placed on the edge pad 112 from being too close to the cutting edge 1211, and thus preventing the solder ribbon from causing excessive pressure on the cutting edge 1211 and its vicinity, which could lead to cracking. On the other hand, designing the first spacing D1 to be less than or equal to 4mm is also beneficial in preventing the edge pad 112 from being too far from the cutting edge 1211, thereby ensuring that the edge pad 112 has good collection efficiency for the charge carriers generated in the portion of the battery substrate 101 located in the edge region 121.

[0121] In other cases, in the initial cell, along the direction from the edge region to the center region, the width of the passivation layer on the edge region that connects with the cut edge may be smaller than the width of the passivation layer on the edge region that connects with the cut edge in other processes for the side of the initial cell that has not undergone the cut process.

[0122] In other embodiments, in conjunction with reference to Figures 7 to 11 The surface of the battery substrate 101, on which the first conductive portion 102 is provided, includes a central region 111 and an edge region 121 surrounding the central region 111. The first conductive portion 102 may include a grid line 122 located on the battery substrate 101. A passivation layer 103 is located at least on the side of the grid line 122 located in the edge region 121 away from the battery substrate 101. The grid line 122 is located not only in the edge region 121 but also in the central region 111.

[0123] It is worth noting that during the manufacturing process of photovoltaic cells, the portion of the grid line 122 located in the edge region 121 is more susceptible to the effects of various manufacturing processes than the portion located in the central region 111. In particular, the passivation layer 103 plated around the edge tends to cover the side of the portion of the grid line 122 located in the edge region 121 that is away from the cell substrate 101. In the absence of solder pads, the passivation layer 103 will isolate the solder ribbon and the portion of the grid line 122 located in the edge region 121, making it impossible for the solder ribbon to be electrically connected to the portion of the grid line 122 located in the edge region 121.

[0124] Based on this, an ultrasonic welding process is used to weld the second conductive part 104 on the side of the passivation layer 103 away from the edge region 121 of the gate line 122. This is beneficial to remove the influence of the passivation layer 103 on the gate line 122 by using the ultrasonic welding process and the cooperation of the second conductive part 104. By contacting the second conductive part 104 and the part of the gate line 122 located in the edge region 121, the carrier transmission channel is opened. The subsequent electrical connection between the solder strip and the second conductive part 104 can further collect the carriers collected by the gate line 122.

[0125] In both of the above embodiments, in conjunction with the reference Figure 14 and Figure 2 The step of providing an initial battery cell 100 may include: providing a whole battery cell 10; cutting the whole battery cell 10 to obtain at least two initial battery cells 100; wherein the aspect ratio of the initial battery cell 100 may be 1.6 to 3.49, for example, it may be 1.6 to 2, 2 to 2.5, 2.5 to 3 or 3 to 3.49, etc. Optionally, the aspect ratio of the initial solar cell 100 can be 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, 2.55, 2.6, 2.65, 2.7, 2.75, 2.8, 2.85, 2.9, 2.95, 3, 3.05, 3.1, 3.15, 3.2, 3.25, 3.3, 3.35, 3.4, 3.45, or 3.49, etc.

[0126] In some cases, the length L of the entire battery 10 can be 210mm~218mm, for example, 210mm~214mm or 214mm~218mm; the width W of the entire battery 10 can be 182mm~183mm, for example, 182mm~182.5mm or 182.5mm~183mm; during the cutting process of the entire battery 10, the entire battery 10 is divided into M initial battery pieces 100 along the length direction of the entire battery 10, where M is a positive integer greater than 1. Then the length of the initial battery piece 100 is 182mm~183mm, and the width of the initial battery piece 100 is (210mm~218mm) / M.

[0127] In some examples, the length L of the entire battery 10 can be 210mm, 210.5mm, 211mm, 211.5mm, 212mm, 212.5mm, 213mm, 213.5mm, 214mm, 214.5mm, 215mm, 215.5mm, 216mm, 216.5mm, 217mm, 217.5mm, or 218mm, etc.

[0128] In some examples, the width W of the entire battery 10 can be 182mm, 182.1mm, 182.2mm, 182.3mm, 182.4mm, 182.5mm, 182.6mm, 182.7mm, 182.8mm, 182.9mm, or 183mm, etc.

[0129] In some embodiments, reference Figure 2 The material of the passivation layer 103 may include at least one of silicon nitride, silicon oxide, or aluminum oxide.

[0130] In some embodiments, reference Figure 2 Along the first direction X, the thickness of the passivation layer 103 can be 40nm~50nm. It is worth noting that during the ultrasonic welding process, the thickness of the passivation layer 103 affects the efficiency of removing at least part of the passivation layer 103; in other words, it affects the ease with which the second conductive part 104 penetrates the passivation layer 103 to make contact with the first conductive part 102.

[0131] Based on this, the thickness of the passivation layer 103 is designed to be 40nm~50nm, which can at least match the ultrasonic power of the first stage in the ultrasonic welding process, so as to ensure that the second conductive part 104 penetrates the passivation layer 103 to make contact with the first conductive part 102.

[0132] In some embodiments, reference Figure 4 The material of the second conductive part 104 may include at least one of tin, lead-tin alloy, silver-tin alloy, silver-copper-tin alloy or zinc-tin alloy.

[0133] In some embodiments, reference Figure 4 Additionally, a solder strip (not shown in the figure) can be formed on the side of the second conductive portion 104 away from the battery substrate 101, and the solder strip is electrically connected to the second conductive portion 104.

[0134] In some cases, solder ribbon can be either tin-coated or tin-free. Tin-coated solder ribbon refers to a ribbon with an outer layer of tin and an inner core that can be made of other conductive materials, such as copper.

[0135] In some cases, the initial cell 100 also includes grid lines 122 located on the cell substrate 101, the grid lines 122 extending along the second direction Y, and the solder strips extending along the third direction Z.

[0136] It should be noted that the first direction X, the second direction Y, and the third direction Z intersect each other pairwise. In one example, the first direction X, the second direction Y, and the third direction Z can be orthogonal to each other. In practical applications, the angle formed by any two of the first, second, and third directions can be either acute or obtuse.

[0137] The intersection of the first direction X and the second direction Y includes the following scenarios: the first direction X and the second direction Y are orthogonal; the included angle is obtuse; or the included angle is acute. In some examples, the included angle of the first direction X and the second direction Y can be between 10° and 90°, for example, 10°, 20°, 45°, 55°, 70°, 82°, or 90°. In some specific examples, the included angle of the first direction X and the second direction Y can also be between 45° and 90°. It should be noted that the intersection of the second direction Y and a third direction Z, and the intersection of the first direction X and a third direction Z, are similar to the cases of the intersection of the first direction X and the second direction Y described above, and will not be elaborated further here.

[0138] In summary, by utilizing a first stage with higher ultrasonic power, a portion of the passivation layer 103 is broken through by mechanical vibration or shock waves at a higher frequency, or in other words, the passivation layer 103 is shattered and removed. This results in at least pores appearing in the passivation layer 103 or at least a portion of the passivation layer 103 being removed. Consequently, the second conductive part 104 penetrates the passivation layer 103 and directly contacts and connects with the first conductive part 102, ensuring the contact connection between the first conductive part 102 and the second conductive part 104. Furthermore, the higher ultrasonic power in the first stage can enhance the exposure of the passivation layer 103. The area of ​​the first conductive part 102 is increased, thereby increasing the contact area between the second conductive part 104 and the first conductive part 102. Subsequently, with the help of a second stage with lower ultrasonic power, the second conductive part 104 is further embedded in the first conductive part 102 to further increase the contact area between the second conductive part 104 and the first conductive part 102, and can also improve the connection strength between the second conductive part 104 and the first conductive part 102. Thus, the conductivity between the second conductive part 104 and the first conductive part 102 can be improved from both structural stability and contact area perspectives.

[0139] Another embodiment of this disclosure provides a photovoltaic cell manufacturing apparatus for implementing the photovoltaic cell manufacturing method provided in the foregoing embodiments. The photovoltaic cell manufacturing apparatus provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0140] refer to Figure 15 , Figure 15 This is a functional module schematic diagram of a photovoltaic cell manufacturing apparatus according to another embodiment of the present disclosure. The photovoltaic cell manufacturing apparatus includes: a conveying module 106 for providing an initial cell 100; an ultrasonic welding module 107 for welding a second conductive part 104 onto the initial cell 100; the ultrasonic welding module 107 includes a control unit 117 for setting the process parameters of the ultrasonic welding module 107, such that the ultrasonic welding process includes at least a first stage and a second stage, wherein the ultrasonic power of the first stage is greater than the ultrasonic power of the second stage.

[0141] Thus, the ultrasonic welding process can be flexibly controlled by the control unit 117 in the ultrasonic welding module 107, allowing at least a portion of the passivation layer 103 covering the first conductive part 102 to be removed, exposing a portion of the first conductive part 102 away from the battery substrate 101, facilitating contact connection between the second conductive part 104 and the first conductive part 102. Furthermore, the control unit 117 can further regulate the process, causing a portion of the second conductive part 104 to embed into the first conductive part 102, thereby improving the conductivity between the second conductive part 104 and the first conductive part 102 in terms of both structural stability and contact area.

[0142] Another embodiment of this disclosure provides a photovoltaic cell, formed by the manufacturing method of the photovoltaic cell provided in the foregoing embodiments, or formed by the manufacturing apparatus of the photovoltaic cell provided in the foregoing embodiments. The photovoltaic cell provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0143] refer to Figure 6 or Figure 11 The photovoltaic cell includes: an initial cell 100, which may include: a cell substrate 101; a first conductive portion 102 located on the cell substrate 101; and a second conductive portion 104, at least a portion of which is located on the side of the first conductive portion 102 away from the cell substrate 101.

[0144] The first conductive part 102 is used to collect charge carriers in the battery substrate 101. At least part of the second conductive part 104 is in contact with the first conductive part 102. The charge carriers collected by the first conductive part 102 can be further collected by the second conductive part 104, so that the subsequent solder ribbon can directly collect the charge carriers in multiple initial battery cells 100 by means of the second conductive part 104.

[0145] The specific structures of the second conductive part 104 and the first conductive part 102 will be described in detail below.

[0146] In some embodiments, reference Figure 6 or Figure 11The second conductive portion 104 may include a body portion 114 and a protrusion 124. The body portion 114 is in contact with the first conductive portion 102, and the protrusion 124 is embedded in the first conductive portion 102. It is worth noting that a passivation layer 103 may not be sandwiched between the second conductive portion 104 and the first conductive portion 102. This helps to maximize the contact area between the first conductive portion 102 and the second conductive portion 104, thereby reducing the contact resistance between the first conductive portion 102 and the second conductive portion 104, and thus reducing carrier transport losses. Furthermore, the protrusion 124 can improve the connection strength between the second conductive portion 104 and the first conductive portion 102, thereby improving the structural stability of the photovoltaic cell.

[0147] In other embodiments, reference is made to... Figure 5 , Figure 10 or Figure 13 The second conductive portion 104 may include a body portion 114 and a protrusion 124. The photovoltaic cell may further include a passivation layer 103 located between the body portion 114 and the first conductive portion 102 along a first direction X. The protrusion 124 penetrates the passivation layer 103 and is embedded in the first conductive portion 102. The first direction X is the thickness direction of the cell substrate 101. In this way, the protrusion 124 can improve the connection strength between the second conductive portion 104 and the first conductive portion 102, thereby improving the structural stability of the photovoltaic cell.

[0148] The passivation layer 103 is located on at least a portion of the first conductive portions 102 or on a portion of the first conductive portions 102.

[0149] In some cases, the thickness of the passivation layer 103 along the first direction X can be 40nm to 50nm, for example, 40nm to 45nm or 45nm to 50nm. Preferably, the thickness of the passivation layer 103 can be 40nm, 41nm, 42nm, 43nm, 44nm, 45nm, 46nm, 47nm, 48nm, 49nm, 50nm, 51nm, 52nm, 53nm, 54nm, 55nm, 56nm, 57nm, 58nm, 59nm, or 60nm, etc.

[0150] In the two embodiments described above, along the first direction X, the ratio of the embedding depth of the protrusion 124 in the first conductive portion 102 to the thickness of the first conductive portion 102 can be greater than or equal to 50% and less than 100%, for example, it can be 50%~60%, 60%~70%, 70%~80%, 80%~90%, or 90%~100%. Preferably, the ratio of the embedding depth of the protrusion 124 in the first conductive portion 102 to the thickness of the first conductive portion 102 can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, or 95%, etc.

[0151] It is worth noting that the deeper the protrusion 124 is embedded in the first conductive portion 102, the better it is for improving the connection strength between the second conductive portion 104 and the first conductive portion 102. Thus, on the one hand, designing the ratio of the embedding depth of the protrusion 124 in the first conductive portion 102 to the thickness of the first conductive portion 102 to be greater than or equal to 50% helps ensure a high connection strength between the second conductive portion 104 and the first conductive portion 102; on the other hand, designing the ratio of the embedding depth of the protrusion 124 in the first conductive portion 102 to the thickness of the first conductive portion 102 to be less than 100% can prevent the second conductive portion 104 from penetrating the first conductive portion 102 to contact the battery substrate 101, thereby avoiding additional interface defects at the interface where the first conductive portion 102 and the battery substrate 101 contact, and reducing the risk of carrier recombination.

[0152] In the two embodiments described above, the ratio of the projected area of ​​the protrusion 124 on the battery substrate 101 to the projected area of ​​the first conductive part 102 on the battery substrate 101 is a first ratio, which can be greater than or equal to 50% and less than 100%.

[0153] It is worth noting that the projected area of ​​the protrusion 124 on the battery substrate 101 can characterize the contact area between the protrusion 124 and the first conductive portion 102 in the horizontal direction. Thus, the ratio of the projected area of ​​the protrusion 124 on the battery substrate 101 to the projected area of ​​the first conductive portion 102 on the battery substrate 101 is greater than or equal to 50%, which helps ensure that the protrusion 124 and the first conductive portion 102 also have a large contact area in the horizontal direction, further ensuring good conductivity between the second conductive portion 104 and the first conductive portion 102.

[0154] In some embodiments, reference Figure 5 , Figure 6 , Figure 10 or Figure 11 Along the first direction X, the body portion 114 and the first conductive portion 102 overlap or coincide.

[0155] In some cases, refer to Figure 5 or Figure 6 The orthographic projection of the body portion 114 on the battery substrate 101 may coincide with the orthographic projection of the first conductive portion 102 on the battery substrate 101. In other cases, the orthographic projection of the first conductive portion on the battery substrate may be located within the orthographic projection of the body portion on the battery substrate, or the orthographic projection of the body portion on the battery substrate may be located within the orthographic projection of the first conductive portion on the battery substrate, or the orthographic projection of the first conductive portion on the battery substrate and the orthographic projection of the body portion on the battery substrate may only partially overlap.

[0156] In some embodiments, reference Figure 5 or Figure 6 In the first direction X, the thickness of the body portion 114 can be 10μm to 15μm, for example, it can be 10μm to 11μm, 11μm to 12μm, 12μm to 13μm, 13μm to 14μm or 14μm to 15μm, etc.

[0157] Optionally, the thickness of the body portion 114 can be 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm or 15μm, etc.

[0158] Another embodiment of this disclosure provides a photovoltaic module, which includes multiple photovoltaic cells formed by the manufacturing method of photovoltaic cells as provided in the foregoing embodiments, or multiple photovoltaic cells formed by the manufacturing apparatus of photovoltaic cells as provided in the foregoing embodiments, or multiple photovoltaic cells as provided in the foregoing embodiments. The photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated below.

[0159] Reference Figure 16 and Figure 17 The photovoltaic module includes: a battery string, which is formed by connecting multiple photovoltaic cells 40 formed by the manufacturing method of photovoltaic cells provided in the foregoing embodiments, or by connecting multiple photovoltaic cells 40 formed by the manufacturing apparatus of photovoltaic cells provided in the foregoing embodiments, or by connecting multiple photovoltaic cells 40 provided in the foregoing embodiments; an encapsulating film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulating film 41 facing away from the battery string.

[0160] in, Figure 16 A partial three-dimensional structural diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure; Figure 17 This is a partial cross-sectional structural diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0161] In some cases, multiple photovoltaic cells 40 can be electrically connected via solder ribbons 43. It is worth noting that electrical connection actually means that both are made of conductive materials and are directly connected or connected via other conductive materials. Therefore, when the photovoltaic cells 40 are generating electricity, there is an electrical connection between them.

[0162] It should be noted that, Figure 16 and Figure 17This illustration only shows one positional relationship between photovoltaic cells 40, where each photovoltaic cell 40 has a first electrode and a second electrode on the same side, and the sides with the first and second electrodes are arranged facing the same direction, so that the solder ribbon 43 connects the same side of two adjacent photovoltaic cells 40 respectively. In other embodiments, the photovoltaic cells may also be arranged such that the sides with electrodes of two adjacent photovoltaic cells are located on different sides, in which case the solder ribbon connects the different sides of two adjacent photovoltaic cells.

[0163] In some embodiments, the photovoltaic cells 40 are electrically connected in the form of a single cell or multiple segments to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The photovoltaic cells 40 can be a single cell or a sliced ​​cell, where a sliced ​​cell refers to a cell formed by cutting a complete single cell.

[0164] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the photovoltaic cell 40, and the second encapsulating layer covers the other of the front or back sides of the photovoltaic cell 40. Specifically, at least one of the first encapsulating layer or the second encapsulating layer may be an organic encapsulating film such as polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), polyolefin thermoplastic elastomer (POE), or polyethylene glycol terephthalate (PET). Alternatively, at least one of the first encapsulating layer or the second encapsulating layer may also be an EP film, an EPE film, or a PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0165] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0166] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0167] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A method for manufacturing a photovoltaic cell, characterized in that, include: An initial battery cell is provided, the initial battery cell comprising: a battery substrate; a first conductive portion located on the battery substrate; and a passivation layer located on at least a portion of the first conductive portion or on a portion of the first conductive portion; The second conductive part is welded using an ultrasonic welding process on the side of the passivation layer away from the first conductive part. The ultrasonic welding process includes at least a first stage and a second stage, wherein the ultrasonic power in the first stage is greater than the ultrasonic power in the second stage; in the first stage, pores appear in the passivation layer or at least a portion of the passivation layer is removed; in the second stage, a portion of the second conductive part is embedded in the first conductive part.

2. The method for manufacturing a photovoltaic cell according to claim 1, characterized in that, The second conductive part includes a body part and a protrusion part. The passivation layer covered by the second conductive part is completely removed in the ultrasonic welding process. The body part is in contact with the first conductive part, and the protrusion part is embedded in the first conductive part.

3. The method for manufacturing a photovoltaic cell according to claim 2, characterized in that, The second conductive portion includes a body portion and a protrusion portion. Part of the passivation layer is removed during the ultrasonic welding process, and the remaining passivation layer is located between the body portion and the first conductive portion. The protrusion portion is also embedded in the passivation layer.

4. The method for manufacturing a photovoltaic cell according to claim 1, characterized in that, The ratio of the ultrasonic power in the second stage to the ultrasonic power in the first stage is greater than or equal to 0.2 and less than 1.

5. The method for manufacturing a photovoltaic cell according to claim 1 or 4, characterized in that, The ultrasonic power of the first stage is 15W~20W; and / or, the ultrasonic power of the second stage is 10W~20W.

6. The method for manufacturing a photovoltaic cell according to claim 1, characterized in that, The welding temperature of the ultrasonic welding process is 200℃~300℃.

7. The method for manufacturing a photovoltaic cell according to claim 1, characterized in that, The surface of the battery substrate having the first conductive portion includes a central region and an edge region surrounding the central region. The first conductive portion includes edge pads located in the edge region, and the passivation layer is located on at least a portion of the edge pads on the side away from the battery substrate.

8. The method for manufacturing a photovoltaic cell according to claim 7, characterized in that, The initial battery cell further includes: a central pad located in the central region; with the battery substrate as a reference plane, the top surface of the central pad away from the battery substrate is higher than the top surface of the edge pad away from the battery substrate.

9. The method for manufacturing a photovoltaic cell according to claim 1, characterized in that, The surface of the battery substrate having the first conductive portion includes a central region and an edge region surrounding the central region. The first conductive portion includes a grid line on the battery substrate, and the passivation layer is located at least on the side of the grid line located in the edge region away from the battery substrate.

10. A method for manufacturing a photovoltaic cell according to any one of claims 7 to 9, characterized in that, The step of providing the initial battery cell includes: providing a whole battery cell; cutting the whole battery cell to obtain at least two initial battery cells; wherein the aspect ratio of the initial battery cell is 1.6 to 3.

49.

11. The method for manufacturing a photovoltaic cell according to claim 7 or 8, characterized in that, The step of providing the initial battery cell includes: providing a whole battery cell; cutting the whole battery cell to obtain at least two initial battery cells; wherein the initial battery cell includes at least one cut surface, the edge region near the cut surface has a cut edge, the distance between the edge pad and the cut edge is a first distance, the distance between the passivation layer and the cut edge is a second distance, and the first distance is less than or equal to the second distance.

12. The method for manufacturing a photovoltaic cell according to claim 11, characterized in that, The first spacing is 2mm to 4mm.

13. A photovoltaic cell manufacturing apparatus for implementing the photovoltaic cell manufacturing method as described in any one of claims 1 to 12, characterized in that, include: A delivery module is used to provide the initial battery cells; An ultrasonic welding module is used to weld the second conductive part onto the initial battery cell; the ultrasonic welding module includes a control unit, which is used to set the process parameters of the ultrasonic welding module so that the ultrasonic welding process includes at least a first stage and a second stage, wherein the ultrasonic power of the first stage is greater than the ultrasonic power of the second stage.

14. A photovoltaic cell, characterized in that, include: An initial battery cell, the initial battery cell comprising: a battery substrate; and a first conductive portion located on the battery substrate; The second conductive portion, at least a portion of which is located on the side of the first conductive portion away from the battery substrate, includes a body portion and a protrusion portion, wherein the protrusion portion is embedded in the first conductive portion; The main body portion is in contact with the first conductive portion; or, the photovoltaic cell further includes a passivation layer, which is located between the main body portion and the first conductive portion, and the protrusion penetrates the passivation layer along a first direction. The first direction is the thickness direction of the battery substrate.

15. The photovoltaic cell according to claim 14, characterized in that, Along the first direction, the thickness of the passivation layer is 40nm~50nm.

16. The photovoltaic cell according to claim 14 or 15, characterized in that, Along the first direction, the thickness of the body portion is 10μm~15μm.

17. The photovoltaic cell according to claim 14, characterized in that, Along the first direction, the ratio of the embedding depth of the protrusion in the first conductive portion to the thickness of the first conductive portion is greater than or equal to 50% and less than 100%.

18. The photovoltaic cell according to claim 14, characterized in that, The ratio of the projected area of ​​the protrusion on the battery substrate to the projected area of ​​the first conductive part on the battery substrate is a first ratio, which is greater than or equal to 50% and less than 100%.

19. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple photovoltaic cells formed by the manufacturing method of photovoltaic cells as described in any one of claims 1 to 12, or by connecting multiple photovoltaic cells formed by the manufacturing apparatus of photovoltaic cells as described in claim 13, or by connecting multiple photovoltaic cells as described in any one of claims 14 to 18. An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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