Solar cell, cell assembly, and photovoltaic system

Abstract

The present disclosure is applicable to the technical field of solar cells, and provides a solar cell, a cell assembly, and a photovoltaic system. The solar cell comprises a cell substrate, first main busbars, second main busbars, first fingers, and second fingers. The first main busbars and the second main busbars are located on the cell substrate and extend in a first direction and are alternately distributed in a second direction. The first and second main busbars comprise a first region segment and a second region segment in the first direction, and the first region segment is wider than the second region segment in the second direction. An extending length of the first fingers is less than that of the second fingers. This allows the second fingers to extend further, resulting in high current-collection efficiency. Because the width of the first region segment is greater than that of the second region segment, the first region segment can reduce electrical energy loss, and the second region segment can reduce material usage and lower manufacturing costs.

Description

A solar cell, a cell assembly and a photovoltaic system

[0001] The present disclosure claims priority to and the benefit of the filing date of Chinese Patent Application No. CN202421804205.0, filed on July 26, 2024, with the China National Intellectual Property Office, and incorporates herein by reference in its entirety. TECHNICAL FIELD

[0002] The present disclosure belongs to the technical field of solar cells, and in particular relates to a solar cell, a cell assembly and a photovoltaic system. BACKGROUND

[0003] Solar energy is a sustainable clean energy source, and solar cells can convert solar energy into electrical energy using the photovoltaic effect of a p-n junction. Currently, a solar cell is a semiconductor device that directly converts the energy of sunlight into electrical energy. The solar cell uses the photovoltaic effect to excite electrons by absorbing photons and guide these electrons out to generate current through the built-in electric field. At this time, the grid line can collect and transmit the current, thereby realizing the conversion of light energy into electrical energy. However, in the related art, the cross section of the main grid cannot be too small, otherwise it will result in a large resistance, and increasing the cross-sectional area of the main grid will increase the consumption of the material for preparing the main grid, and at the same time will result in that the fine grid often cannot fully cover the silicon substrate, thereby increasing the manufacturing cost of the solar cell and reducing the conversion efficiency of the electrical energy.

[0004] UTILITARIAN CONTENT

[0005] The present disclosure provides a solar cell, a cell assembly and a photovoltaic system, aiming to solve the problem of conversion efficiency and production cost of photovoltaic cells.

[0006] In the solar cell of the present disclosure, the solar cell includes a cell piece base body, a first main grid line, a second main grid line, a first fine grid line and a second fine grid line, the first main grid line and the second main grid line are located on the cell piece base body, the first main grid line and the second main grid line extend along a first direction and are alternately distributed along a second direction, the first main grid line and the second main grid line include a first region segment and a second region segment along the first direction, the width of the first region segment is greater than the width of the second region segment in the second direction, and the first region segment and the second region segment are non-welding region segments; the first fine grid line and the second fine grid line are electrically connected with the first main grid line respectively, the first fine grid line is located in the first region segment, and the second fine grid line is located in the second region segment; the length of the first fine grid line extending to the second main grid line is less than the length of the second fine grid line extending to the second main grid line.

[0007] Furthermore, in the second direction, the distance between the end of the first fine grid line and the end of the second fine grid line to the second main grid line is 0.35mm-0.45mm.

[0008] Further, the first main busbar and the second main busbar have a width in the second direction of 10-300 μm.

[0009] Further, the first region section has a width in the second direction of 100-300 μm, and the second region section has a width in the second direction of 10-100 μm.

[0010] Further, the solar cell further comprises a busbar structure, the busbar structure being located on the first main busbar and the second main busbar.

[0011] Further, the first main busbar further comprises a third region section connecting the first region section and the second region section in the first direction, the third region section having a width in the second direction gradually changing in the first direction.

[0012] Further, in the first region section, at least one of the first main busbar and the second main busbar has a constant width.

[0013] Further, in the first region section, at least one of the first main busbar and the second main busbar has a gradually changing width.

[0014] Further, in the second region section, at least one of the first main busbar and the second main busbar has a constant width, or in the second region section, at least one of the first main busbar and the second main busbar has a gradually changing width.

[0015] Further, at least one of the first fine busbar and the second fine busbar has a width in the first direction gradually decreasing from a side close to the first main busbar in the second direction.

[0016] The embodiments of the present disclosure further provide a battery assembly, the battery assembly comprising a battery string, the battery string comprising the solar cell of any one of the above.

[0017] The embodiments of the present disclosure further provide a photovoltaic system, the photovoltaic system comprising the battery assembly of the above embodiments.

[0018] In the solar cell and the photovoltaic module according to the embodiments of the present disclosure, the solar cell comprises a cell substrate, a first main grid line, a second main grid line, a first fine grid line and a second fine grid line. The first main grid line and the second main grid line are located on the cell substrate. The first main grid line and the second main grid line extend along a first direction and are alternately distributed along a second direction. The first main grid line and the second main grid line comprise a first region segment and a second region segment along the first direction. The width of the first region segment is greater than the width of the second region segment along the second direction. The first region segment and the second region segment are non-welding region segments. The first fine grid line and the second fine grid line are electrically connected to the first main grid line respectively. The first fine grid line is located on the first region segment, and the second fine grid line is located on the second region segment. The length of the first fine grid line extending to the second main grid line is less than the length of the second fine grid line extending to the second main grid line. In this way, the second fine grid line extends on the surface of the cell substrate as much as possible, and can effectively collect current and has high efficiency. The width of the first region segment is greater than the width of the second region segment. The first region segment can reduce power loss and improve stability, and the second region segment can save materials to reduce the manufacturing cost of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0019] FIG. 1 is a schematic diagram of a partial structure of a solar cell according to an embodiment of the present disclosure;

[0020] FIG. 2 is another schematic diagram of a partial structure of a solar cell according to an embodiment of the present disclosure;

[0021] FIG. 3 is still another schematic diagram of a partial structure of a solar cell according to an embodiment of the present disclosure;

[0022] FIG. 4 is yet another schematic diagram of a partial structure of a solar cell according to an embodiment of the present disclosure;

[0023] FIG. 5 is a schematic diagram of a structure of a cell string according to an embodiment of the present disclosure;

[0024] FIG. 6 is a schematic diagram of a structure of a cell module according to an embodiment of the present disclosure;

[0025] FIG. 7 is a schematic diagram of a structure of a photovoltaic system according to an embodiment of the present disclosure.

[0026] Main element symbol explanation: 100, solar cell; 10, cell substrate; 20, first main grid line; 30, second main grid line; 41, first region segment; 42, second region segment; 43, third region segment; 50, first fine grid line; 60, second fine grid line; 70, bus structure; 200, cell string; 300, cell module; 400, photovoltaic system. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the present disclosure will be further described in detail below with reference to the drawings and embodiments. Examples of the embodiments are shown in the drawings, in which the same or similar notations denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are merely used to explain the present disclosure, and should not be understood as limiting the present disclosure. In addition, it should be understood that the specific embodiments described herein are merely used to explain the present disclosure, and should not be used to limit the present disclosure.

[0028] In the description of the present disclosure, it should be understood that the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are merely used to facilitate the description of the present disclosure and simplify the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present disclosure.

[0029] In addition, the terms "first", "second" are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more features. In the description of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0030] In the description of the present disclosure, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection, or integrally connected; it can be mechanical connection, or electrical connection or can communicate with each other; it can be directly connected, or indirectly connected through an intermediate medium, or the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present disclosure can be understood according to the specific circumstances.

[0031] In the present disclosure, unless otherwise explicitly specified and limited, "on" or "under" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, "on", "above" and "above" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. "Below", "below" and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0032] The disclosure below provides many different embodiments or examples for implementing different structures of the disclosure. For the sake of simplicity, the description below of a particular embodiment or example is provided in terms of specific components and arrangements. Of course, they are merely examples and are not intended to limit the disclosure. Further, the disclosure can repeat reference numerals and / or letters in various examples and / or throughout the specification. This repetition of reference numerals and / or letters is for the purpose of simplicity and clarity and is not intended to carry or imply a relationship or common purpose between the various embodiments and / or uses disclosed. In addition, the disclosure provides various examples of specific processes and materials, but one of ordinary skill in the art will appreciate that other processes and / or materials can be used.

[0033] In the related art, the solar cell utilizes the photovoltaic effect to excite electrons by absorbing photons and guide these electrons out to generate current by the built-in electric field. At this time, the grid line can collect and transmit the current, thereby realizing the conversion of light energy into electric energy. However, in order to meet the highest efficiency of energy conversion, the cross section of the main grid cannot be too small, otherwise it will cause a large resistance, and increasing the cross-sectional area of the main grid will increase the consumption of the material for preparing the main grid, and at the same time will cause the fine grid to often fail to fully cover the silicon substrate, thereby increasing the manufacturing cost of the solar cell and reducing the conversion efficiency of electric energy. In the embodiment, the second fine grid line extends as much as possible on the surface of the cell substrate, which can effectively collect the current and has high efficiency. The width of the first region section is greater than the width of the second region section, the first region section can reduce the loss and improve the stability, and the second region section can save materials to reduce the manufacturing cost of the solar cell.

[0034] Embodiment one

[0035] Please refer to FIG. 1 and FIG. 2, the solar cell 100 in the embodiment of the disclosure includes a cell substrate 10, a first main grid line 20, a second main grid line 30, a first fine grid line 50 and a second fine grid line 60, the first main grid line 20 and the second main grid line 30 are located on the cell substrate 10, the first main grid line 20 and the second main grid line 30 extend along the first direction and are alternately distributed along the second direction, the first main grid line 20 and the second main grid line 30 include a first region section 41 and a second region section 42 along the first direction, the width of the first region section 41 is greater than the width of the second region section 42 in the second direction, and the first region section 41 and the second region section 42 are non-welding region sections; the first fine grid line 50 and the second fine grid line 60 are electrically connected with the first main grid line 20 respectively, the first fine grid line 50 is located in the first region section 41, and the second fine grid line 60 is located in the second region section 42; the length of the first fine grid line 50 extending to the second main grid line 30 is less than the length of the second fine grid line 60 extending to the second main grid line 30.

[0036] In the solar cell 100 of this embodiment, the solar cell 100 includes a cell substrate 10, a first main grid line 20, a second main grid line 30, a first fine grid line 50, and a second fine grid line 60. The first main grid line 20 and the second main grid line 30 are located on the cell substrate 10. The first main grid line 20 and the second main grid line 30 extend along a first direction and are alternately distributed along a second direction. The first main grid line 20 and the second main grid line 30 include a first region segment 41 and a second region segment 42 along the first direction. In the second direction, the width of the first region segment 41 is greater than the width of the second region segment 42. The first region segment 41 and the second region segment 42 are non-welded region segments. The first fine grid line 50 and the second fine grid line 60 are electrically connected to the first main grid line 20. The first fine grid line 50 is located in the first region segment 41, and the second fine grid line 60 is located in the second region segment 42. The length of the first fine grid line 50 extending toward the second main grid line 30 is less than the length of the second fine grid line 60 extending toward the second main grid line 30. Thus, the second fine grid line 60 extends as far as possible on the surface of the cell substrate 10, which can effectively collect current and achieve high efficiency. The width of the first region segment 41 is greater than the width of the second region segment 42. The first region segment 41 can reduce losses and improve stability, while the second region segment 42 can save materials to reduce the manufacturing cost of the solar cell 100.

[0037] Specifically, the first main grid line 20 and the second main grid line 30 located on the solar cell substrate 10 extend along a first direction, and are alternately distributed along a second direction. That is, a large number of main grid lines with opposite polarities are alternately distributed along the second direction of the solar cell substrate 10. These main grid lines are distributed alternately along the second direction of the solar cell substrate 10 according to a positive-negative-positive-negative pattern. In this embodiment, the polarity of the first main grid line 20 and the second main grid line 30 is not limited; "first" and "second" are only used to distinguish between two types of main grid lines. Thus, the alternating distribution of many sets of main grid lines with opposite polarities along the second direction avoids excessively long fine grid lines that reduce transmission efficiency, and the provision of multiple main grid lines shortens the current transmission path in the fine grid lines, thereby improving photoelectric conversion efficiency.

[0038] Furthermore, the first main grid line 20 includes a first region segment 41 and a second region segment 42, which are distributed along a first direction. Similarly, the second main grid line 30 also includes a first region segment 41 and a second region segment 42, which are also distributed along the first direction. Meanwhile, the first region segment 41 and the second region segment 42 have different widths in the second direction. The width of the first region segment 41 is greater than that of the second region segment 42, which increases the overall cross-sectional area of ​​the main grid line, thereby reducing resistance and improving the energy conversion efficiency. The width of the second region segment 42 is smaller than that of the first region segment 41, so that the material consumption for fabricating the main grid line does not increase significantly, reducing fabrication costs. At the same time, the smaller width of the second region segment 42 provides sufficient space for the fine grid lines to cover the cell substrate 10, further improving the energy conversion efficiency.

[0039] Furthermore, the first region segments 41 and 42 of the first main grid line 20 and the second main grid line 30 can be correspondingly configured such that the upper ends and lower ends of the two first region segments 41 can form a rectangle when connected by fine grid lines in the first direction, and the corresponding ends of the two second region segments 42 can also form a rectangle when connected. Moreover, the first region segments 41 and 42 are non-welded region segments.

[0040] Furthermore, the first fine grid line 50 and the second fine grid line 60 are both connected to the first main grid line 20 and have the same polarity. The first main grid line 20 can correspond to multiple sets of fine grid lines, each set of which can have one first fine grid line 50 and one second fine grid line 60, so that multiple sets of fine grid lines can cover the surface of the cell substrate 10. The multiple sets of fine grid lines collect the photocurrent generated on the cell substrate 10 and transmit it to the first main grid line 20.

[0041] Furthermore, the first fine grid line 50 and the second fine grid line 60 extend towards the second main grid line 30 along the second direction. Because the first main grid line 20 and the second main grid line 30 are alternately distributed along the second direction of the cell substrate 10, the second main grid line 30 is distributed on both sides of the first main grid line 20, and the first fine grid line 50 and the second fine grid line 60 extend towards the two second main grid lines 30 on both sides of the first main grid line 20. Simultaneously, the first fine grid line 50 is located in the first region segment 41. Since the two first region segments 41 of the first main grid line 20 and the second main grid line 30 are correspondingly arranged and both have a relatively large width, they occupy more space, thus reducing the area that the first fine grid line 50 can cover in the first region segment 41, thereby reducing the length of the first fine grid line 50. The second fine gate line 60 is located in the second region segment 42. Since the two second region segments 42 of the first main gate line 20 and the second main gate line 30 are correspondingly arranged and both have small widths, they occupy less area, allowing the second fine gate line 60 to cover a larger area. Therefore, the length of the second fine gate line 60 can be larger. In this way, the length of the first fine gate line 50 is smaller than that of the second fine gate line 60. Thus, the larger width of the first region segment 41 of the first main gate line 20 can reduce resistance and manufacturing costs, while the longer length of the second fine gate line 60 can ensure photoelectric conversion efficiency.

[0042] Furthermore, in this embodiment, the term "non-welding section" for the first region segment 41 and the second region segment 42 means that neither the first region segment 41 nor the second region segment 42 is directly connected to the solder strip. In other words, the first region segment 41 and the second region segment 42 are not used for soldering the solder strip; the solder strip can be soldered to other locations on the first main grid line 20 and the second main grid line 30. For example, pads or similar structures can be provided on the main grid line, and then the solder strip is soldered onto the pads.

[0043] Example 2

[0044] Referring to Figures 1 and 2, in some optional embodiments, in the second direction, the distance between the end of the first fine gate line 50 and the end of the second fine gate line 60 to the second main gate line 30 is 0.35mm-0.45mm. For example, in the second direction, the distance between the end of the first fine gate line 50 and the end of the second fine gate line 60 to the second main gate line 30 can be set to 0.35mm, 0.36mm, 0.37mm, 0.38mm, 0.39mm, 0.40mm, 0.41mm, 0.42mm, 0.43mm, 0.44mm, or 0.45mm.

[0045] In this embodiment, the first fine grid line 50 and the second fine grid line 60 extend from the first main grid line 20 along a second direction toward the second main grid line 30. Since the first main grid line 20 and the second main grid line 30 have opposite polarities, they cannot be connected together to avoid short circuits in the cell substrate 10. Therefore, the ends of the first fine grid line 50 and the second fine grid line 60 connected to the first main grid line 20 should maintain a certain distance from the second main grid line 30. For example, the distance between the ends of the first fine grid line 50 and the second fine grid line 60 and the second main grid line 30 can be 0.35mm, 0.37mm, 0.39mm, 0.41mm, 0.43mm, or 0.45mm. This avoids direct connection between the first main grid line 20 and the second main grid line 30 while maximizing the coverage length of the first fine grid line 50 and the second fine grid line 60, thereby improving the photoelectric conversion efficiency while ensuring the safety and reliability of the solar cell 100.

[0046] Of course, in other embodiments, an insulating layer may be provided between the ends of the first fine grid line 50 and the second fine grid line 60 and the second main grid line 30, the insulating layer can prevent the fine grid line and the second main grid line 30 from contacting each other.

[0047] Example 3

[0048] Please refer to Figures 1 and 2. In some optional embodiments, the width of the first main gate line 20 and the second main gate line 30 in the second direction is 10μm-300μm.

[0049] Specifically, if the width of the main grid line is too small, the resistance of the solar cell 100 will increase; if the width of the main grid line is too large, it will block more light and occupy the coverage area of ​​the fine grid lines, reducing the photoelectric conversion efficiency and increasing production costs. Therefore, to ensure low resistance and high energy conversion efficiency of the solar cell 100 and to control production costs, the width of the first main grid line 20 and the second main grid line 30 in the second direction should be limited. For example, the width of the first main grid line 20 and the second main grid line 30 in the second direction can be 10μm, 30μm, 50μm, 70μm, 90μm, 110μm, 130μm, 150μm, 170μm, 190μm, 210μm, 230μm, 250μm, 270μm, 290μm, or 300μm.

[0050] Furthermore, the widths of the first main gate line 20 and the second main gate line 30 in the second direction can be the same or different; no specific limitation is imposed here to meet different requirements. In one example, the widths of both the first main gate line 20 and the second main gate line 30 in the second direction are 100 μm.

[0051] Example 4

[0052] Please refer to Figures 1 and 2. In some optional embodiments, the width of the first region segment 41 in the second direction is 100μm-300μm, and the width of the second region segment 42 in the second direction is 10μm-100μm.

[0053] In this embodiment, the widths of the first region segment 41 and the second region segment 42 in the second direction are different; the first region segment 41 is wider than the second region segment 42, therefore their width ranges are different. For example, the width of the first region segment 41 can be: 100μm, 125μm, 150μm, 175μm, 200μm, 225μm, 250μm, 275μm, or 300μm; the width of the second region segment 42 can be: 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, or 100μm. Thus, the width of the first region segment 41 will be greater than that of the second region segment 42.

[0054] Specifically, both the first main grid line 20 and the second main grid line 30 include a first region segment 41 and a second region segment 42. The first region segment 41 and the second region segment 42 are located at different positions in the first direction. The first region segment 41 has a larger width and can carry a larger current, while the second region segment 42 has a smaller width, which allows the fine grid line to be extended as much as possible to increase the efficiency of current collection.

[0055] Example 5

[0056] Referring to Figures 1 and 2, in some alternative embodiments, the solar cell 100 further includes a busbar structure 70 located on the first main grid line 20 and the second main grid line 30. Exemplarily, the busbar structure 70 can be a solder joint (or a pad point). As one possible implementation, the busbar structure 70 can be connected to the first region segment 41.

[0057] Specifically, the polarities of the first main grid line 20 and the second main grid line 30 are opposite. There should be at least two bus structures 70 (positive bus structure and negative bus structure) connected to the positive main grid line and the negative main grid line respectively. In this way, the bus structures 70 of the positive and negative terminals of the solar cell 100 can be connected to an external circuit, and the electrical energy generated by the solar cell 100 can be stored or transmitted using the external circuit.

[0058] For example, the first section 41 of the first main gate line 20 and the second main gate line 30 has a larger width, connecting the bus structure 70 to the wider first section 41. This wider main gate line has lower resistance and can carry a larger current, thereby reducing energy loss when current in the main gate line converges to the bus structure 70 and improving current transmission efficiency.

[0059] It is understood that, in this embodiment of the disclosure, the bus structure 70 may be located at the end of the first region segment 41 that is away from the second region segment 42.

[0060] As one possible approach, in this embodiment of the disclosure, the first region segment 41 is located at both ends of two adjacent bus structures 70 of the main grid line, and the second region segment 42 is located in the middle of two adjacent bus structures 70 to ensure stable connection.

[0061] Example 6

[0062] Please refer to Figures 1 and 2. In some optional embodiments, the first main grid line 30 further includes a third region segment 43 along the first direction. The third region segment 43 connects the first region segment 41 and the second region segment 42 respectively. In the first direction, the width of the third region segment 43 gradually changes in the second direction.

[0063] Specifically, a third region segment 43 is provided between the first region segment 41 and the second region segment 42. That is, the first region segment 41 and the second region segment 42 are not directly connected, but are connected through the third region segment 43. Furthermore, since the first region segment 41 is wider than the second region segment 42, the third region segment 43 should be set with a gradually changing width when connecting the first region segment 41 and the second region segment 42 to match the two regions with different widths. For example, the third region segment 43 can be set with a gradually changing width from wide to narrow. The wider end of the third region segment 43 connects to the first region segment 41 and is set to the same width as one end of the first region segment 41, while the narrower end of the third region segment 43 connects to the second region segment 42 and is set to the same width as one end of the second region segment 42. This makes the width transition of the entire main grid line smoother, and also makes the resistance change inside the main grid line more gradual, increasing the reliability of the main grid line and reducing the differences caused by the width change of the main grid line.

[0064] Example 7

[0065] Referring to Figures 2 and 3, in some alternative embodiments, at least one of the first main gate line 20 and the second main gate line 30 has a constant width in the first region segment 41.

[0066] For example, the width of the first region segment 41 of the first main gate line 20 may be fixed, and the width of the first region segment 41 of the second main gate line 30 may also be fixed; or the width of the first region segment 41 of the first main gate line 20 may be fixed, and the width of the first region segment 41 of the second main gate line 30 may be variable; or the width of the first region segment 41 of the first main gate line 20 may be variable, and the width of the first region segment 41 of the second main gate line 30 may be fixed; or the width of the first region segment 41 of the first main gate line 20 may be variable, and the width of the first region segment 41 of the second main gate line 30 may also be variable.

[0067] In this way, a wider main grid line can be set in the location of higher current and a narrower main grid line can be set in the location of lower current. The width of the first section 41 of the main grid line can be set according to the actual application requirements or manufacturing capabilities.

[0068] Example 8

[0069] Referring to Figures 3 and 4, in some alternative embodiments, at least one of the first main gate line 20 and the second main gate line 30 has a width gradient in the first region segment 41.

[0070] For example, the width of the first region segment 41 of the first main gate line 20 may be gradual, and the width of the first region segment 41 of the second main gate line 30 may also be gradual; or the width of the first region segment 41 of the first main gate line 20 may be gradual, and the width of the first region segment 41 of the second main gate line 30 may be fixed; or the width of the first region segment 41 of the first main gate line 20 may be fixed, and the width of the first region segment 41 of the second main gate line 30 may be gradual.

[0071] Thus, since the first section 41 of the main grid line is connected to the bus structure 70, the current collected by the fine grid lines from the main grid line converges into the bus structure 70 through the first section. This results in a larger current in the first section 41 closer to the bus structure 70, and a smaller current in the section further away from the bus structure 70. Therefore, the width of the first section 41 does not need to be fixed; it can be varied according to the current magnitude. This allows the section 41 closer to the bus structure 70 to be wider, and the section further away to be narrower, creating a gradually changing width based on distance from the bus structure 70. This gradual width ensures low resistance in the first section 41 while saving materials and reducing production costs.

[0072] Of course, the width of the first segment 41 on the main grid line of different polarities can be set to vary or the degree and direction of width change according to specific needs, in order to meet various requirements.

[0073] In some embodiments, the first region segment 41 and the third region segment 43 can gradually change at a certain slope, making the main grid lines overall coordinated and stable, and they can be fabricated together during the fabrication process. In some embodiments, the first region segment 41, the third region segment 43, and the second region segment 42 can gradually change at a certain slope, making the main grid lines overall coordinated and stable. In this case, the main grid lines become narrower closer to the middle, thereby saving material and reducing the manufacturing cost of the solar cell.

[0074] Example 9

[0075] Referring to Figures 1 and 2, in some alternative embodiments, the first main gate line 20 and the second main gate line 30 are arranged at equal intervals along a second direction, and the first fine gate line 50 and the second fine gate line 60 are arranged along a first direction.

[0076] For example, the first main gate line 20 and the second main gate line 30 are equally spaced along the second direction, and the first fine gate line 50 and the second fine gate line 60 are equally spaced along the first direction; or the first main gate line 20 and the second main gate line 30 are equally spaced along the second direction, and the first fine gate line 50 and the second fine gate line 60 are not equally spaced along the first direction; or the first main gate line 20 and the second main gate line 30 are not equally spaced along the second direction, and the first fine gate line 50 and the second fine gate line 60 are equally spaced along the first direction; or the first main gate line 20 and the second main gate line 30 are not equally spaced along the second direction, and the first fine gate line 50 and the second fine gate line 60 are not equally spaced along the first direction.

[0077] For example, to allow the current from the fine grid lines to converge onto the main grid line, the equal spacing of the first fine grid line 50 and the second fine grid line 60 ensures that the distance between adjacent connection points formed by each fine grid line and the main grid line is equal. This allows the current converging from the fine grid lines to the main grid line to accumulate sequentially with the increase of connection points. Since the equal spacing of the first fine grid line 50 and the second fine grid line 60 ensures that the distance between adjacent connection points formed by each fine grid line and the main grid line is equal, the current in the main grid line that increases or decreases sequentially with the number of connection points will be approximately the same. This allows for the calculation of the current magnitude in different sections of the main grid line, facilitating the setting of the width of the main grid line or the degree of width gradient. This ensures low resistance of the main grid line and allows it to carry a corresponding current while also maintaining low production costs.

[0078] For example, the current in the main grid line is to be converged into the bus structure 70. The first main grid line 20 and the second main grid line 30 are arranged at equal intervals along the second direction. At the same time, the first fine grid line 50 and the second fine grid line 60 are also arranged at equal intervals. In this way, the number of fine grid lines in the area corresponding to each bus structure 70 is approximately the same, or in other words, the area of ​​the current collected by the bus structure 70 is approximately the same.

[0079] Understandably, as another approach, the area of ​​the bus structure 70 (or the size of the bus structure 70#A) can vary with the area of ​​the region where the current is collected. For example, the area of ​​the region corresponding to the bus structure 70#A is area #A, and the area of ​​the region corresponding to the bus structure 70#B is area #B. If area #A is larger than area #B, then the area of ​​the bus structure 70#A is larger than the area of ​​the bus structure 70#B. Furthermore, the first main gate line 20 and the second main gate line 30 can be arranged with non-equidistant spacing along the second direction, or the first fine gate line 50 and the second fine gate line 60 can be arranged with non-equidistant spacing along the first direction. This embodiment does not limit the spacing between the fine gate lines and the main gate lines to meet various needs. Of course, in this embodiment, when the main gate lines and fine gate lines are not equidistant, the size of the bus structure 70 can also be adjusted accordingly. For example, when the bus structure 70 has a large number of fine grid lines, the area of ​​the bus structure 70 itself increases; when the bus structure 70 has a small number of fine grid lines, the area of ​​the bus structure 70 itself decreases.

[0080] Referring to Figures 1 and 2, in some alternative embodiments, at least one of the first fine gate line 50 and the second fine gate line 60 has a width that gradually decreases in the second direction from the side closest to the first main gate line 20 in the first direction.

[0081] This makes the conduction current of the first fine grid line 50 and the second fine grid line 60 more stable, which can reduce the use of fine grid paste and reduce costs while enhancing connection stability.

[0082] Example 10

[0083] Please refer to Figure 5. This disclosure also provides a battery string 200, which includes the solar cell 100 of any of the above embodiments.

[0084] In this embodiment, the battery string 200 can be a series connection of multiple sheet-like solar cells 100 connected by solder ribbons and busbars. It is understood that the battery string 200 can include two, three, or more solar cells connected in series, depending on the specific application. Furthermore, in this embodiment, the size and type of the solar cells 100 are not limited; adjacent solar cells can have the same or different specifications and dimensions to meet different needs.

[0085] In this disclosure, the specific connection method of adjacent solar cells is not limited to meet different needs. In one embodiment, the edges of two adjacent solar cells are at least partially stacked together; in another embodiment, two adjacent solar cells can be spaced apart. A suitable spacing between two adjacent solar cells avoids both insufficient spacing leading to limited operating space and difficult welding, and excessive spacing leading to wasted component space and increased costs.

[0086] Example 11

[0087] Please refer to Figure 6. This disclosure also provides a battery assembly 300, which includes the battery string 200 of the above embodiments.

[0088] It is understood that in such an embodiment, the battery module 300 may further include a frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back of the solar cell 100, as well as between the photovoltaic glass and adjacent cells. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0089] Photovoltaic glass can be applied to the encapsulating film on the front side of the solar cell 100. This photovoltaic glass can be ultra-clear glass, possessing high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%, protecting the solar cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the solar cell 100 together, providing sealing, insulation, and waterproofing / moisture protection for the solar cell 100.

[0090] The backsheet can be attached to the adhesive film on the back of the solar cell 100. The backsheet provides protection and support for the solar cell 100, and has reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, solar cell 100, adhesive film, and photovoltaic glass can be integrated into a frame. The frame serves as the main external support structure for the entire battery module 300, providing stable support and installation for the battery module 300. For example, the battery module 300 can be installed at the desired location via the frame.

[0091] Example 12

[0092] Please refer to Figure 7. This disclosure also provides a photovoltaic system 400, which includes the battery module 300 of the above embodiments.

[0093] In this embodiment, the photovoltaic system 400 can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system 400 are not limited to these; that is, the photovoltaic system 400 can be applied in all fields that require solar energy for power generation. Taking a photovoltaic power generation system grid as an example, the photovoltaic system 400 may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules 300. For example, multiple battery modules 300 can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0094] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0095] Furthermore, the above are merely preferred embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A solar cell, wherein, include: Solar cell substrate; The first main busbar and the second main busbar are located on the cell substrate. The first main busbar and the second main busbar extend along a first direction and are alternately distributed along a second direction. The first main busbar and the second main busbar include a first region segment and a second region segment along the first direction. In the second direction, the width of the first region segment is greater than the width of the second region segment. The first region segment and the second region segment are non-welded region segments. A first fine gate line and a second fine gate line are electrically connected to the first main gate line respectively, wherein the first fine gate line is located in the first region segment and the second fine gate line is located in the second region segment; The length by which the first fine gate line extends toward the second main gate line is less than the length by which the second fine gate line extends toward the second main gate line.

2. The solar cell according to claim 1, wherein, In the second direction, the distance between the end of the first fine grid line and the end of the second fine grid line and the second main grid line is 0.35mm-0.45mm.

3. The solar cell according to claim 1, wherein, The width of the first main gate line and the second main gate line in the second direction is 10μm-300μm.

4. The solar cell according to claim 3, wherein, The width of the first region segment in the second direction is 100μm-300μm, and the width of the second region segment in the second direction is 10μm-100μm.

5. The solar cell according to claim 4, wherein, The solar cell also includes a busbar structure located on the first main grid line and the second main grid line.

6. The solar cell according to claim 1, wherein, The first main grid line further includes a third region segment along the first direction. The third region segment connects the first region segment and the second region segment respectively. In the first direction, the width of the third region segment gradually changes in the second direction.

7. The solar cell according to claim 1, wherein, In the first region segment, at least one of the first main gate line and the second main gate line has a constant width.

8. The solar cell according to claim 1, wherein, In the first region segment, at least one of the first main gate line and the second main gate line has a width gradient.

9. The solar cell according to claim 1, wherein in the second region segment, at least one of the first main grid line and the second main grid line has a constant width, or in the second region segment, at least one of the first main grid line and the second main grid line has a gradually changing width.

10. The solar cell according to claim 1, wherein, The width of at least one of the first fine gate line and the second fine gate line gradually decreases in the first direction from the side closest to the first main gate line along the second direction.

11. A battery assembly, wherein, It includes a battery string, the battery string comprising a solar cell as described in any one of claims 1-10.

12. A photovoltaic system, wherein, Includes the battery assembly as described in claim 11.

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