Back contact cells and photovoltaic modules

Abstract

The embodiments of the present disclosure relate to the photovoltaic field and provide a back-contact cell and a photovoltaic module, wherein the back-contact cell comprises: a cell substrate having first and second welding areas alternately arranged along a first direction; a first and second fine grids located on the cell substrate and alternately arranged along a second direction, the first fine grid having a first break on the first welding area, and the second fine grid having a second break on the second welding area; a first conduit located in the first welding area, filling the first break and covering a portion of the top surface of the first fine grid away from the cell substrate; a second conduit located in the second welding area, filling the second break and covering a portion of the top surface of the second fine grid away from the cell substrate; the direction of the cell substrate pointing to the first fine grid is a reference direction, and a plane perpendicular to the reference direction is a reference plane, and along the reference direction, the cross-sectional areas of the first break and the second break on the reference plane tend to gradually increase, which is at least beneficial to improving the flatness of both the first conduit and the second conduit.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaics, and in particular to a back-contact cell and a photovoltaic module. Background Art

[0002] With the gradual depletion of fossil fuels, photovoltaic cells are becoming increasingly popular as a new energy alternative. Photovoltaic cells are devices that convert sunlight into electricity. They utilize the principle of photovoltaics to generate charge carriers, which are then extracted using grid lines, thereby facilitating the efficient use of electrical energy. The grid lines of photovoltaic cells play a vital role in collecting and transmitting electrons. When assembling photovoltaic modules from multiple photovoltaic cells, soldering tape is often used to electrically connect the grid lines of adjacent photovoltaic cells.

[0003] In current back-contact photovoltaic cells, a bus structure for collecting current on fine grids is generally connected to fine grids with the same polarity as the fine grids, and is electrically insulated from fine grids with different polarity.

[0004] However, when the contact connection between the welding strip and the bus structure is subsequently achieved, the overlap design based on the bus structure and the fine grid can easily cause the welding strip to bend and uneven force to be applied to different areas, which can further easily affect the contact stability between the welding strip and the bus structure. Therefore, a more preferred bus structure needs to be sought. Summary of the Invention

[0005] The embodiments of the present disclosure provide a back-contact cell and a photovoltaic module, which are at least beneficial for improving the flatness of both the first busbar and the second busbar.

[0006] According to some embodiments of the present disclosure, on one hand, the embodiments of the present disclosure provide a back-contact battery, comprising: a battery substrate, the battery substrate having a first welding area and a second welding area alternately arranged along a first direction; a first fine grid and a second fine grid located on the battery substrate and alternately arranged along a second direction, the first fine grid having a first break on the first welding area, and the second fine grid having a second break on the second welding area; a first bus located in the first welding area, filling the first break and covering a portion of the first fine grid away from the top surface of the battery substrate, the first bus being electrically insulated from the second fine grid; a second bus located in the second welding area, filling the second break and covering a portion of the second fine grid away from the top surface of the battery substrate, the second bus being electrically insulated from the first fine grid; wherein the direction of the battery substrate pointing to the first fine grid is a reference direction, a plane perpendicular to the reference direction is a reference plane, and along the reference direction, the cross-sectional areas of the first break and the second break on the reference plane tend to gradually increase.

[0007] In some embodiments, the first fine grid further has a first isolation opening on the second welding area for achieving electrical insulation between the first fine grid and the second busbar; the second fine grid further has a second isolation opening on the first welding area for achieving electrical insulation between the second fine grid and the first busbar; the first fine grid includes a plurality of first fine grid branches spaced apart along the first direction, and two adjacent first fine grid branches are spaced apart along the first direction to form a first fracture or a first isolation opening, the first fine grid branch has a first end in contact with the first busbar, and with a plane perpendicular to the first direction as a reference section, the cross-sectional area of the first end gradually decreases along the direction of the first end approaching the first busbar; the second fine grid includes a plurality of second fine grid branches spaced apart along the first direction, and two adjacent second fine grid branches are spaced apart along the first direction to form a second fracture or a second isolation opening, the second fine grid branch has a second end in contact with the second busbar, and the cross-sectional area of the second end gradually decreases along the direction of the second end approaching the second busbar.

[0008] In some embodiments, the thickness of the first end portion in the reference direction gradually decreases along the direction of the first end portion approaching the first confluence portion; the thickness of the second end portion in the reference direction gradually decreases along the direction of the second end portion approaching the second confluence portion.

[0009] In some embodiments, the thickness of the first end portion in the reference direction decreases by 1 um for every 0.05 mm length along the direction of the first end portion close to the first confluence portion; and / or, the thickness of the second end portion in the reference direction decreases by 1 um for every 0.05 mm length along the direction of the second end portion close to the second confluence portion.

[0010] In some embodiments, along the first direction, the ratio of the width of the first fracture to the width of the first confluence is 1 / 3~3 / 4; and / or, along the first direction, the ratio of the width of the second fracture to the width of the second confluence is 1 / 3~3 / 4.

[0011] In some embodiments, the back-contact battery is a main-grid battery; the first busbar includes a first main grid, and a plurality of first pads that are in contact with and connected to the first main grid and arranged at intervals along the second direction; the second busbar includes a second main grid, and a plurality of second pads that are in contact with and connected to the second main grid and arranged at intervals along the second direction.

[0012] In some embodiments, along the first direction, the width of the first break filled by the first main gate is smaller than the width of the first break filled by the first pad; and / or, along the first direction, the width of the second break filled by the second main gate is smaller than the width of the second break filled by the second pad.

[0013] In some embodiments, the first fine grid further has a first isolation opening on the second welding area, and the second fine grid further has a second isolation opening on the first welding area; wherein, along the first direction, the ratio of the width of the first isolation opening for accommodating the second main grid to the width of the second pad is 0.9~1, and the ratio of the width of the first isolation opening for accommodating the second pad to the width of the second pad is 1.6~1.8; and / or, along the first direction, the ratio of the width of the second isolation opening for accommodating the first main grid to the width of the first pad is 0.9~1, and the ratio of the width of the second isolation opening for accommodating the first pad to the width of the first pad is 1.6~1.8.

[0014] In some embodiments, the back-contact battery is a main-grid-less battery; the first busbar is a first welding point, and each first fine grid and the first welding area intersect with a first welding point, and the same first welding point is in contact with at least one first fine grid; the second busbar is a second welding point, and each second fine grid and the second welding area intersect with a second welding point, and the same second welding point is in contact with at least one second fine grid.

[0015] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic module, including: a cell string, which is formed by connecting a plurality of back-contact cells as described in any one of the above items; a packaging film, which is used to cover the surface of the cell string; and a cover plate, which is used to cover the surface of the packaging film facing away from the cell string.

[0016] The technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0017] First, the first fine grid is designed to have a first break on the first welding region. This facilitates accommodating the first busbar through the first break, effectively reducing the height difference between the portion of the first busbar filling the first break and the rest of the first busbar along the second direction, thereby improving the overall flatness of the first busbar and reducing the amount of material required to manufacture the first fine grid. Furthermore, the first busbar is designed to cover a portion of the first fine grid away from the top surface of the battery substrate, ensuring sufficient contact between the first busbar and the first break, thereby enhancing the connection strength between the first busbar and the first fine grid. Furthermore, the cross-sectional area of the first break on the reference surface is designed to gradually increase along the reference direction, further increasing the volume of the first busbar accommodated within the first break. This further reduces the height difference between the portion of the first busbar filling the first break and the rest of the first busbar along the second direction, thereby further improving the overall flatness of the first busbar. While maintaining the contact area between the first fine grid and the battery substrate, this further reduces the amount of material required to manufacture the first fine grid.

[0018] Similarly, the second fine grid is designed to have a second break on the second welding area, which is beneficial for accommodating the second busbar through the second break, effectively reducing the height difference between the portion of the second busbar that fills the second break and the rest of the portion along the second direction, thereby improving the overall flatness of the second busbar and saving the amount of material required to prepare the second fine grid. In addition, the second busbar is designed to cover a portion of the second fine grid away from the top surface of the battery substrate, which is beneficial for ensuring sufficient contact between the second busbar and the second break, thereby improving the connection strength between the second busbar and the second fine grid. Furthermore, along the reference direction, the cross-sectional area of the second break on the reference surface is designed to gradually increase, which is beneficial for further reducing the height difference between the portion of the second busbar that fills the second break and the rest of the portion along the second direction, thereby further improving the overall flatness of the second busbar and further saving the amount of material required to prepare the second fine grid while ensuring that the contact area between the second fine grid and the battery substrate remains unchanged.

[0019] Secondly, whether the aforementioned coordinated design of the first fine grid and the first busbar, or the aforementioned coordinated design of the second fine grid and the second busbar, when subsequently achieving contact and connection between the soldering ribbon and the first busbar or the second busbar, on the one hand, can significantly reduce the extent to which the soldering ribbon located on the top surface of the first busbar or the second busbar is pushed out, thereby reducing the degree of bending of the soldering ribbon itself and increasing the service life of the soldering ribbon. On the other hand, insulating glue will be subsequently provided on portions of the top surfaces of both the first fine grid and the second fine grid. Based on this, the first break can be used to block the insulating glue provided on the first fine grid from further spreading, thereby preventing the insulating glue from being mixed into the junction between the first busbar and the soldering ribbon, for example, preventing the insulating glue from causing solder paste to flow away at the junction between the first busbar and the soldering ribbon. The second break can also be used to block the insulating glue provided on the second fine grid from further spreading, thereby preventing the insulating glue from being mixed into the junction between the second busbar and the soldering ribbon, for example, preventing the insulating glue from causing solder paste to flow away at the junction between the second busbar and the soldering ribbon. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 A first partial top view schematic diagram of a back-contact battery provided by an embodiment of the present disclosure;

[0022] Figure 2 A second partial top view schematic diagram of a back-contact battery provided by an embodiment of the present disclosure;

[0023] Figure 3 A third partial top view schematic diagram of a back-contact battery provided in one embodiment of the present disclosure;

[0024] Figure 4 A first partial cross-sectional schematic diagram of a back-contact battery provided by an embodiment of the present disclosure;

[0025] Figure 5 A second partial cross-sectional schematic diagram of a back-contact battery provided by an embodiment of the present disclosure;

[0026] Figure 6 A partial top view schematically showing a first fine grid and a first busbar in a back-contact battery provided in one embodiment of the present disclosure;

[0027] Figure 7 A partial top view schematically showing a second fine grid and a second busbar in a back-contact battery provided in an embodiment of the present disclosure;

[0028] Figure 8 A fourth partial top view schematic diagram of a back-contact battery provided by an embodiment of the present disclosure;

[0029] Figure 9 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure;

[0030] Figure 10 for Figure 9 A schematic partial cross-sectional view along the first cross-sectional direction AA1. DETAILED DESCRIPTION

[0031] As can be seen from the background art, the design of a bus structure for collecting current on fine grids needs further research.

[0032] After analysis, it was found that the fine grid is located on the battery substrate, and the bus structure used to collect the current on the fine grid is generally overlapped on the fine grid with the same polarity. In this way, compared with the part of the bus structure that is on the same layer as the fine grid, the part of the bus structure located on the fine grid will be more protruding, resulting in an uneven morphology of the bus structure as a whole. When the contact connection between the welding ribbon and the bus structure is subsequently achieved, the welding ribbon located on the bus structure can be regarded as being pushed out relative to the welding ribbon located on the battery substrate. In other words, based on the unevenness of the bus structure, it is easy to cause the height difference between the welding ribbon located on the bus structure and the battery substrate to be too large, resulting in a large degree of bending of the welding ribbon, causing local stress concentration on the battery substrate, prone to battery substrate fragmentation, and affecting the contact stability between the welding ribbon and the bus structure.

[0033] The present disclosure provides a back-contact cell and photovoltaic module. In the back-contact cell, first, a first fine grid is designed to have a first break on a first welding region, and along a reference direction, the cross-sectional area of the first break on the reference surface tends to gradually increase. This is beneficial for maximizing the volume of the first conduit contained within the first break, minimizing the height difference between the portion of the first conduit that fills the first break and the rest of the portion along the second direction, thereby maximizing the overall flatness of the first conduit. Furthermore, while ensuring that the contact area between the first fine grid and the cell substrate remains unchanged, the amount of material required to prepare the first fine grid is minimized. Furthermore, the first conduit is designed to cover a portion of the top surface of the first fine grid away from the cell substrate, which is beneficial for ensuring sufficient contact between the first conduit and the first break, thereby enhancing the connection strength between the first conduit and the first fine grid. Similarly, the second fine grid is designed to have a second fracture on the second welding area, and along the reference direction, the cross-sectional area of the second fracture on the reference surface tends to gradually increase, which is beneficial to minimizing the height difference between the portion of the second busbar that fills the second fracture and the other portions along the second direction, thereby maximizing the overall flatness of the second busbar, and further saving the amount of material required to prepare the second fine grid while ensuring that the contact area between the second fine grid and the battery substrate remains unchanged. In addition, the second busbar is designed to cover a portion of the top surface of the second fine grid away from the battery substrate, which is beneficial to ensure sufficient contact between the second busbar and the second fracture, thereby improving the connection strength between the second busbar and the second fine grid. Secondly, when the welding strip is subsequently connected to the first busbar or the second busbar, on the one hand, the degree to which the welding strip on the top surface of the first busbar or the second busbar is pushed out can be significantly reduced, thereby reducing the degree of bending of the welding strip itself and improving the service life of the welding strip. On the other hand, insulating glue will be set on part of the top surface of the first fine grid and the second fine grid in the future. Based on this, the first break can block the insulating glue set on the first fine grid from spreading further, so as to avoid the phenomenon of insulating glue being mixed into the junction between the first busbar and the welding strip; the second break can block the insulating glue set on the second fine grid from spreading further, so as to avoid the phenomenon of insulating glue being mixed into the junction between the second busbar and the welding strip.

[0034] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0035] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0037] In the description of the embodiments of the present disclosure, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0038] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0039] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and they can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0040] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of layers are exaggerated for better understanding and ease of description. 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 a third component may be present between the two components. Conversely, when a component is described as being on the surface of another component, or as being formed or disposed on the surface of one component, it indicates that there is no third component between the two components. Furthermore, when a component is described as being "substantially" formed on another component, this means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0041] In the description of the embodiments of the present disclosure, when a component is referred to as "including" another component, unless otherwise specified, this does not exclude other components, and other components may further be included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them) or another component may be present between them. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "directly on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, this means that no other components are located between them.

[0042] The terms used herein in the description of the various embodiments are intended only to describe the specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is intended to include the plural form unless the context clearly indicates otherwise. A component includes a layer, film, region, or plate.

[0043] The following describes various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, those skilled in the art will appreciate that many technical details are provided in the various embodiments of the present disclosure to help readers better understand the embodiments of the present disclosure. However, even without these technical details and the various variations and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0044] An embodiment of the present disclosure provides a back-contact battery, which will be described in detail below with reference to the accompanying drawings.

[0045] Combined with reference Figures 1 to 8The back contact battery comprises: a battery substrate 101 having a first welding area 111 and a second welding area 121 alternately arranged along a first direction X; a first fine grid 102 and a second fine grid 103 located on the battery substrate 101 and alternately arranged along a second direction Y, the first fine grid 102 having a first break 112 on the first welding area 111, and the second fine grid 103 having a second break 113 on the second welding area 121; a first conduit 104 located in the first welding area 111, filling the first break 112 and covering the first fine grid 102 away from the battery substrate 1 01, the first bus 104 is electrically insulated from the second fine grid 103; the second bus 105 located in the second welding area 121 fills the second fracture 113 and covers the partial area of the top surface of the second fine grid 103 away from the battery substrate 101, and the second bus 105 is electrically insulated from the first fine grid 102; wherein, the direction from the battery substrate 101 to the first fine grid 102 is the reference direction Z, and the plane perpendicular to the reference direction Z is the reference plane. Along the reference direction Z, the cross-sectional areas of the first fracture 112 and the second fracture 113 on the reference plane tend to gradually increase.

[0046] in, Figure 1 A first partial top view schematic diagram of a back-contact battery provided by an embodiment of the present disclosure; Figure 2 A second partial top view schematic diagram of a back-contact battery provided by an embodiment of the present disclosure; Figure 3 A third partial top view schematic diagram of a back-contact battery provided in one embodiment of the present disclosure; Figure 4 A first partial cross-sectional schematic diagram of a back-contact battery provided by an embodiment of the present disclosure; Figure 5 A second partial cross-sectional schematic diagram of a back-contact battery provided by an embodiment of the present disclosure; Figure 6 A partial top view schematically showing a first fine grid and a first busbar in a back-contact battery provided in one embodiment of the present disclosure; Figure 7 A partial top view schematically showing a second fine grid and a second busbar in a back-contact battery provided in an embodiment of the present disclosure; Figure 8 A fourth partial top view schematic diagram of a back-contact battery provided in one embodiment of the present disclosure.

[0047] In addition, firstly, to clearly illustrate the design of the first fine gate 102 and the second fine gate 103, Figure 1 The first confluence portion and the second confluence portion are not shown; secondly, Figure 1 、 Figure 2 and Figure 8 In the figure, the first fine grid 102 is indicated by a thicker solid line, and the second fine grid 103 is indicated by a thinner solid line. Figures 3 to 5 Different filling methods are used to draw the first fine grid 102 and the second fine grid 103; thirdly, the reference direction X can be regarded as a direction perpendicular to the battery substrate 101.

[0048] It should be noted that the first welding area 111 can be regarded as a placement position reserved on the battery substrate 101 for the first busbar 104 that is in contact with and connected to the multiple first fine grids 102; the second welding area 121 can be regarded as a placement position reserved on the battery substrate 101 for the second busbar 105 that is in contact with and connected to the multiple second fine grids 103.

[0049] Based on this, the first fine grid 102 is designed to have a first break 112 on the first welding area 111, so that the first conduit 104 fills the first break 112 to achieve contact connection between the first conduit 104 and the first fine grid 102, so as to collect currents on multiple first fine grids 102, which is beneficial to accommodate the first conduit 104 with the help of the first break 112, and avoid overlapping of the first conduit 104 with the first break 112 as much as possible, thereby effectively reducing the height difference between the part 134 of the first conduit 104 filling the first break 112 and the other parts 144 along the second direction Y in the first conduit 104, which is beneficial to improving the overall flatness of the first conduit 104, and is also beneficial to saving the amount of material required to prepare the first fine grid 102. In addition, the first busbar 104 is designed to cover a portion of the top surface of the first fine grid 102 away from the battery substrate 101, which is conducive to ensuring sufficient contact between the first busbar 104 and the first break 112. In other words, it is ensured that the first busbar 104 fills the first break 112 to ensure sufficient contact area between the first busbar 104 and the first fine grid 102, thereby improving the connection strength between the first busbar 104 and the first fine grid 102, effectively avoiding the problem of poor contact between the first busbar 104 and the first fine grid 102, and improving the fault tolerance rate when forming the first busbar 104. Furthermore, along the reference direction Z, the cross-sectional area of the first fracture 112 on the reference surface is designed to show a gradually increasing trend, which is beneficial to increasing the volume of the first fracture 112 by gradually increasing the opening degree of the first fracture 112, so as to further increase the volume of the first confluence 104 that can be accommodated in the first fracture 112, so as to further reduce the height difference between the part of the first confluence 104 filling the first fracture 112 and other parts along the second direction Y. In other words, more parts of the first confluence 104 are in the same layer as the first fine grid 102 along the second direction Y, thereby further improving the overall flatness of the first confluence 104, and further saving the amount of material required to prepare the first fine grid 102 while ensuring that the contact area between the first fine grid 102 and the battery substrate 101 remains unchanged.

[0050] In some cases, taking the top surface of the first fine grid 102 away from the battery substrate 101 as the reference plane, along the reference direction Z, compared with the height difference between the first busbar and the first fine grid when the two are overlapped, the height difference between the top surface of the first busbar 104 away from the battery substrate 101 and the reference plane can be reduced by about 1 / 4 to 3 / 7, for example, it can be reduced by about 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41 or 0.42, etc. In one example, along the reference direction Z, the height difference between the first busbar and the first fine grid when they are overlapped is approximately 7um~8um. In the first busbar 104 and the first fine grid 102 designed in an embodiment of the present disclosure, the height difference between the top surface of the first busbar 104 away from the battery substrate 101 and the reference plane can be reduced by approximately 2um~3um on the basis of 7um~8um.

[0051] Similarly, the second fine grid 103 is designed to have a second break 113 on the second welding area 121, so that the second conduit 105 fills the second break 113 to achieve contact connection between the second conduit 105 and the second fine grid 103, so as to collect currents on multiple second fine grids 103. This is beneficial for accommodating the second conduit 105 with the help of the second break 113, and avoiding the overlap of the second conduit 105 on the second break 113 as much as possible, thereby effectively reducing the height difference between the part 135 of the second conduit 105 filled with the second break 113 and the other parts 145 along the second direction Y in the second conduit 105, which is beneficial for improving the overall flatness of the second conduit 105, and is also beneficial for saving the amount of material required to prepare the second fine grid 103. In addition, the second busbar 105 is designed to cover a portion of the top surface of the second fine grid 103 away from the battery substrate 101, which is conducive to ensuring sufficient contact between the second busbar 105 and the second break 113. In other words, it is ensured that the second busbar 105 fills the second break 113 to ensure sufficient contact area between the second busbar 105 and the second fine grid 103, thereby improving the connection strength between the second busbar 105 and the second fine grid 103, effectively avoiding the problem of poor contact between the second busbar 105 and the second fine grid 103, and improving the fault tolerance when forming the second busbar 105. Furthermore, along the reference direction Z, the cross-sectional area of the second fracture 113 on the reference surface is designed to show a gradually increasing trend, which is beneficial to increasing the volume of the second fracture 113 by gradually increasing the opening degree of the second fracture 113, so as to further increase the volume of the second convergence part 105 that can be accommodated in the second fracture 113, so as to further reduce the height difference between the part of the second convergence part 105 filling the second fracture 113 and other parts along the second direction Y. In other words, more parts of the second convergence part 105 are in the same layer as the second fine grid 103 along the second direction Y, thereby further improving the overall flatness of the second convergence part 105, and further saving the material required for preparing the second fine grid 103 while ensuring that the contact area between the second fine grid 103 and the battery substrate 101 remains unchanged.

[0052] In some cases, taking the top surface of the second fine grid 103 away from the battery substrate 101 as the reference plane, along the reference direction Z, compared with the height difference between the second busbar and the second fine grid when the two are overlapped, the height difference between the top surface of the second busbar 105 away from the battery substrate 101 and the reference plane can be reduced by about 1 / 4 to 3 / 7, for example, it can be reduced by about 0.26, 0.27, 0.28, 0.29, 0.3, 0.31, 0.32, 0.33, 0.34, 0.35, 0.36, 0.37, 0.38, 0.39, 0.4, 0.41 or 0.42, etc. In one example, along the reference direction Z, the height difference between the second busbar and the second fine grid when they are overlapped is approximately 7um~8um. In the second busbar 105 and the second fine grid 103 designed in an embodiment of the present disclosure, the height difference between the top surface of the second busbar 105 away from the battery substrate 101 and the reference plane can be reduced by approximately 2um~3um on the basis of 7um~8um.

[0053] It is worth noting that, whether it is the matching design of the above-mentioned first fine grid 102 and the first convergence part 104, or the matching design of the above-mentioned second fine grid 103 and the second convergence part 105, when the contact connection between the welding strip and the first convergence part 104 or the second convergence part 105 is subsequently realized, on the one hand, based on the overall flatness of both the first convergence part 104 and the second convergence part 105 being improved, the degree to which the welding strip located on the top surface of the first convergence part 104 or the second convergence part 105 is pushed out can be significantly reduced, so as to reduce the bending degree of the welding strip itself, thereby reducing the stress caused by the welding strip to the battery substrate 101, so as to reduce the risk of the battery substrate 101 being fragmented. In addition, the reduction in the bending degree of the welding strip itself can also improve the service life of the welding strip to a certain extent. On the other hand, insulating glue will be set on part of the top surface of the first fine grid 102 and the second fine grid 103 in the future. Based on this, the first fine grid 102 is designed to have a first break 112, which can prevent the first fine grid 102 from penetrating along the first direction X at the first confluence 104, so as to prevent the insulating glue set on the first fine grid 102 from flowing to the center of the first confluence 104 with the help of the penetrating first fine grid 102. In other words, the insulating glue set on the first fine grid 102 is blocked from further spreading with the help of the first break 112, so as to avoid the phenomenon of insulating glue being mixed into the junction of the first confluence 104 and the solder strip, for example, to avoid the insulating glue from causing the solder paste to be diverted at the junction of the first confluence 104 and the solder strip, so as to prevent the insulating glue from causing the solder paste to be diverted at the junction of the first confluence 104 and the solder strip, so as to prevent the insulating glue from being diverted. Improve the electrical contact performance between the first busbar 104 and the soldering strip; the second fine grid 103 is designed to have a second break 113, which can prevent the second fine grid 103 from penetrating the second busbar 105 along the first direction X, so as to prevent the insulating glue arranged on the second fine grid 103 from flowing to the center of the second busbar 105 with the help of the penetrating second fine grid 103. In other words, the second break 113 is used to block the insulating glue arranged on the second fine grid 103 from further spreading, so as to avoid the phenomenon of insulating glue being mixed into the junction between the second busbar 105 and the soldering strip, for example, to avoid the insulating glue causing the solder paste to be diverted at the junction between the second busbar 105 and the soldering strip, so as to improve the electrical contact performance between the second busbar 105 and the soldering strip.

[0054] It should be noted that Figure 6The dashed line demarcates a portion 134 of the first confluence portion 104 filled with the first break 112 and another portion 144 along the second direction Y. In other words, the portion 134 of the first confluence portion 104 filled with the first break 112 can be considered as the portion of the first confluence portion 104 directly facing the first fine grid 102 along the first direction X, and the other portion 144 of the first confluence portion 104 can be considered as the portion of the first confluence portion 104 not directly facing the first fine grid 102 along the first direction X. Based on the design of the first break 112, the height difference between the portion 134 of the first confluence portion 104 filled with the first break 112 and the other portion 144 can be effectively reduced, and can even eliminate the height difference between the portion 134 of the first confluence portion 104 filled with the first break 112 and the other portion 144.

[0055] also, Figure 7 The dotted line demarcates a portion 135 of the second confluence portion 105 filled with the second break 113 and the other portion 145 along the second direction Y. In other words, the portion 135 of the second confluence portion 105 filled with the second break 113 can be considered as the portion of the second confluence portion 105 directly facing the second fine gate 103 along the first direction X, and the other portion 145 of the second confluence portion 105 can be considered as the portion of the second confluence portion 105 not directly facing the second fine gate 103 along the first direction X. Based on the design of the second break 113, the height difference between the portion 135 of the second confluence portion 105 filled with the second break 113 and the other portion 145 can be effectively reduced, and can even eliminate the height difference between the portion 135 of the second confluence portion 105 filled with the second break 113 and the other portion 145.

[0056] The back contact cell provided by one embodiment of the present disclosure is described in detail below.

[0057] In some embodiments, in conjunction with reference Figure 1 、 Figures 3 to 5 The first fine grid 102 also has a first isolation opening 122 on the second welding area 121, which is used to achieve electrical insulation between the first fine grid 102 and the second busbar 105; the second fine grid 103 also has a second isolation opening 123 on the first welding area 111, which is used to achieve electrical insulation between the second fine grid 103 and the first busbar 104.

[0058] It is worth noting that, for the first fine grid 102, it not only has a first break 112 located on the first welding area 111, but also has a first isolation opening 122 located on the second welding area 121. Based on the alternating arrangement of the first welding area 111 and the second welding area 121 along the first direction X, the first break 112 and the first isolation opening 122 on the same first fine grid 102 are also arranged alternately along the first direction X; for the second fine grid 103, it not only has a second isolation opening 123 located on the first welding area 111, but also has a second break 113 located on the second welding area 121. Based on the alternating arrangement of the first welding area 111 and the second welding area 121 along the first direction X, the second break 113 and the second isolation opening 123 on the same second fine grid 103 are also arranged alternately along the first direction X.

[0059] Based on this, continue to combine reference Figure 1 、 Figures 3 to 5 The first fine gate 102 may include a plurality of first fine gate branches 132 spaced apart along the first direction X, wherein two adjacent first fine gate branches 132 are spaced apart along the first direction X to form a first break 112 or a first isolation opening 122, and the first fine gate branch 132 has a first end portion 132a in contact with the first confluence portion 104. Taking a plane perpendicular to the first direction X as a reference cross-section, the cross-sectional area of the first end portion 132a on the reference cross-section gradually decreases in a direction along the first end portion 132a approaching the first confluence portion 104, which is conducive to ensuring that the cross-sectional area of the first break 112 on the reference plane tends to gradually increase along the reference direction Z.

[0060] It is worth noting that the first fine gate 102 can be considered to be sequentially divided into multiple segments by the first break 112 and the first isolation opening 122. Each segment can be considered a first fine gate branch 132. The end of the first fine gate branch 132 that forms the first break 112 is referred to as the first end 132a. Furthermore, for two adjacent first fine gate branches 132 along the first direction X, the first end 132a can approach the first confluence portion 104 in opposite directions.

[0061] It should be noted that, with the exception of the first fine grid branch 132 located at the edge of the cell substrate 101, the other first fine grid branches 132 have both a first end 132a for forming the first break 112 and an end (not labeled in the figure) for forming the first isolation opening 122. Furthermore, the cross-sectional area of the end of the first fine grid branch 132 for forming the first isolation opening 122, as measured on the reference cross section, can vary gradually, like the first end 132a, or remain constant. In other words, the cross-sectional area of the end of the first fine grid branch 132 for forming the first isolation opening 122, as measured on the reference cross section, can be flexibly designed based on actual needs.

[0062] In some examples, in conjunction with reference Figure 1 、 Figures 3 to 5 The first conduit portion 104 covers the top surface of the first end portion 132a away from the battery substrate 101, and the contact surface between the first conduit portion 104 and the first end portion 132a can be a whole curved surface, for example, a whole curved surface can be similar to a half bullet head curved surface.

[0063] In addition, continue to combine reference Figure 1 、 Figures 3 to 5 The second fine gate 103 may include a plurality of second fine gate branches 133 spaced apart along the first direction X, and a second break 113 or a second isolation opening 123 is formed between two adjacent second fine gate branches 133 along the first direction X. The second fine gate branch 133 has a second end portion 133a in contact with the second confluence portion 105. In the direction in which the second end portion 133a approaches the second confluence portion 105, the cross-sectional area of the second end portion 133a on the reference cross-section gradually decreases, which is conducive to ensuring that the cross-sectional area of the second break 113 on the reference surface tends to gradually increase along the reference direction Z.

[0064] It is worth noting that the second fine gate 103 can be considered to be sequentially divided into multiple segments by the second break 113 and the second isolation opening 123. Each segment can be considered a second fine gate branch 133. The end of the second fine gate branch 133 that forms the second break 113 is referred to as the second end 133a. Furthermore, for two adjacent second fine gate branches 133 along the first direction X, the second end 133a can approach the second confluence portion 105 in opposite directions.

[0065] It should be noted that, with the exception of the second fine gate branches 133 located at the edge of the cell substrate 101, the other second fine gate branches 133 have both second ends 133a for forming the second fractures 113 and ends (not labeled in the figure) for forming the second isolation openings 123. Furthermore, the cross-sectional area of the ends of the second fine gate branches 133 for forming the second isolation openings 123, as measured on the reference cross section, can vary gradually, like the second ends 133a, or remain constant. In other words, the cross-sectional area of the ends of the second fine gate branches 133 for forming the second isolation openings 123, as measured on the reference cross section, can be flexibly designed based on actual needs.

[0066] In some examples, in conjunction with reference Figure 1 、 Figures 3 to 5 The second conduit portion 105 covers the top surface of the second end portion 133a away from the battery substrate 101, and the contact surface between the second conduit portion 105 and the second end portion 133a can be a whole curved surface, for example, a whole curved surface can be similar to a half bullet head curved surface.

[0067] In some cases, reference Figure 4, along the direction of the first end portion 132a approaching the first confluence portion 104, the thickness of the first end portion 132a in the reference direction Z can be gradually reduced to form a first fracture 112 whose cross-sectional area on the reference surface tends to gradually increase along the reference direction Z; Figure 5 , along the direction of the second end 133a approaching the second confluence portion 105, the thickness of the second end 133a in the reference direction Z can gradually decrease to form a second fracture 113 whose cross-sectional area on the reference surface tends to gradually increase along the reference direction Z.

[0068] It should be noted that, in order to ensure that the cross-sectional area of the first fracture 112 on the reference surface tends to gradually increase along the reference direction Z, along the direction of the first end 132a approaching the first confluence 104, not only the thickness of the first end 132a in the reference direction Z can be designed to gradually decrease, but the width of the first end 132a in the second direction Y can also be designed to gradually decrease; in order to ensure that the cross-sectional area of the second fracture 113 on the reference surface tends to gradually increase along the reference direction Z, along the direction of the second end 133a approaching the second confluence 105, not only the thickness of the second end 133a in the reference direction Z can be designed to gradually decrease, but the width of the second end 133a in the second direction Y can also be designed to gradually decrease.

[0069] In some examples, reference Figure 4 , along the direction in which the first end portion 132 a approaches the first confluence portion 104 , the thickness of the first end portion 132 a in the reference direction Z may be reduced by 1 um for every 0.05 mm of length.

[0070] In some examples, reference Figure 5 , along the direction in which the second end portion 133 a approaches the second confluence portion 105 , the thickness of the second end portion 133 a in the reference direction Z may also be reduced by 1 um for every 0.05 mm of length.

[0071] It should be noted that the degree to which the thickness of the first end portion 132 a gradually decreases in the reference direction Z may be the same as or different from the degree to which the thickness of the second end portion 133 a gradually decreases in the reference direction Z.

[0072] In some embodiments, reference Figure 4Along the first direction X, the ratio of the width W1 of the first break 112 to the width W2 of the first conduit 104 can be 1 / 3 to 3 / 4, for example, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.53, 0.55, 0.6, 0.63, 0.65, 0.66, 0.7, or 0.72, etc. It should be noted that regardless of whether the back-contact cell is a back-contact cell with a busbar or a back-contact cell without a busbar, the ratio of the width W1 of the first break 112 to the width W2 of the first conduit 104 can be 1 / 3 to 3 / 4.

[0073] In some examples, the width W1 of the first fracture 112 can be 0.3mm~0.9mm, for example, it can be 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm or 0.85mm, etc.; the width W2 of the first confluence portion 104 can be 0.8mm~1.2mm, for example, it can be 0.85mm, 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm or 1.15mm, etc.

[0074] In some embodiments, reference Figure 5 Along the first direction X, the ratio of the width W3 of the second break 113 to the width W4 of the second converging portion 105 can be 1 / 3 to 3 / 4, for example, 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.53, 0.55, 0.6, 0.63, 0.65, 0.66, 0.7, or 0.72, etc. It should be noted that regardless of whether the back-contact cell is a back-contact cell with a busbar or a back-contact cell without a busbar, the ratio of the width W3 of the second break 113 to the width W4 of the second converging portion 105 can be 1 / 3 to 3 / 4.

[0075] In some examples, the width W3 of the second fracture 113 can be 0.3mm~0.9mm, for example, it can be 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm or 0.85mm, etc.; the width W4 of the second confluence 105 can be 0.8mm~1.2mm, for example, it can be 0.85mm, 0.9mm, 0.95mm, 1.0mm, 1.05mm, 1.1mm or 1.15mm, etc.

[0076] It should be noted that, along the first direction X, the ratio of the width W1 of the first break 112 to the width W2 of the first confluence portion 104 and the ratio of the width W3 of the second break 113 to the width W4 of the second confluence portion 105 may be the same or different.

[0077] The back-contact battery with a main grid and the back-contact battery without a main grid are described in detail below.

[0078] In some embodiments, reference Figure 2 The back-contact battery can be a main-grid battery; the first busbar 104 includes a first main grid 114, and a plurality of first solder pads 124 that are in contact with the first main grid 114 and arranged at intervals along the second direction Y; the second busbar 105 includes a second main grid 115, and a plurality of second solder pads 125 that are in contact with the second main grid 115 and arranged at intervals along the second direction Y.

[0079] It should be noted that, for any first main gate 114, the first main gate 114 and the multiple first pads 124 in contact with the first main gate 114 are regarded as a whole and are regarded as the first busbar 104, and the first welding area 111 can be regarded as the setting area of the first main gate 114 and the first pad 124; for any second main gate 115, the second main gate 115 and the multiple second pads 125 in contact with the second main gate 115 are regarded as a whole and are regarded as the second busbar 105, and the second welding area 121 can be regarded as the setting area of the second main gate 115 and the second pad 125.

[0080] In the first fine gate 102 designed in an embodiment of the present disclosure, not only is a first break 112 provided at the contact connection with the first main gate 114 to accommodate the first main gate 114 and avoid overlapping of the first main gate 114 and the first fine gate 102, thereby effectively reducing the height difference between the portion of the first main gate 114 filled with the first break 112 along the second direction Y and other portions, thereby improving the overall flatness of the first main gate 114; but also a first break 112 is provided at the contact connection with the first solder pad 124 to accommodate the first solder pad 124 and avoid overlapping of the first solder pad 124 and the first fine gate 102, thereby effectively reducing the height difference between the portion of the first solder pad 124 filled with the first break 112 along the second direction Y and other portions, thereby improving the overall flatness of the first solder pad 124.

[0081] Similarly, in the second fine gate 103 designed in an embodiment of the present disclosure, not only is a second break 113 provided at the contact connection with the second main gate 115 to accommodate the second main gate 115 and avoid overlapping of the second main gate 115 and the second fine gate 103, thereby effectively reducing the height difference between the portion of the second main gate 115 filled with the second break 113 and other portions along the second direction Y, thereby improving the overall flatness of the second main gate 115; but also a second break 113 is also provided at the contact connection with the second solder pad 125 to accommodate the second solder pad 125 and avoid overlapping of the second solder pad 125 and the second fine gate 103, thereby effectively reducing the height difference between the portion of the second solder pad 125 filled with the second break 113 and other portions along the second direction Y, thereby improving the overall flatness of the second solder pad 125.

[0082] In some cases, in conjunction with reference Figure 1 and Figure 2 , along the first direction X, the width of the first break 112 filled by the first busbar 114 is smaller than the width of the first break 112 filled by the first pad 124. In other words, along the first direction X, the widths of different first breaks 112 used to accommodate the same first busbar 104 may differ depending on whether they accommodate the first busbar 114 or the first pad 124. It is worth noting that to ensure alignment accuracy and sufficient contact area between the subsequent solder strip and the first busbar 104, along the first direction X, the width of the first busbar 114 is smaller than the width of the first pad 124. Based on this, the width of the first break 112 filled by the first main grid 114 is designed to be smaller than the width of the first break 112 filled by the first soldering pad 124. This is beneficial in ensuring that a sufficient portion of the first soldering pad 124 is accommodated by the first break 112 to improve the overall flatness of the first soldering pad 124. At the same time, by limiting the width of the first break 112 filled by the first main grid 114, the contact area between the first fine grid 102 and the battery substrate 101 is increased as much as possible, thereby improving the efficiency of the first fine grid 102 in collecting photogenerated carriers in the battery substrate 101.

[0083] In practical applications, along the first direction, the width of the first break filled by the first main grid may be equal to the width of the first break filled by the first pad, that is, the widths of different first breaks on the same first busbar may be the same.

[0084] In some cases, in conjunction with reference Figure 1 and Figure 2, along the first direction X, the width of the second break 113 filled by the second busbar 115 is smaller than the width of the second break 113 filled by the second pad 125. In other words, along the first direction X, the widths of different second breaks 113 for accommodating the same second busbar 105 may differ depending on whether they accommodate the second busbar 115 or the second pad 125. It is worth noting that to ensure alignment accuracy and sufficient contact area between the subsequent solder strip and the second busbar 105, along the first direction X, the width of the second busbar 115 is smaller than the width of the second pad 125. Based on this, the width of the second break 113 filled by the second main grid 115 is designed to be smaller than the width of the second break 113 filled by the second soldering pad 125. This is beneficial for ensuring that a sufficient portion of the second soldering pad 125 is accommodated by the second break 113 to improve the overall flatness of the second soldering pad 125. At the same time, by limiting the width of the second break 113 filled by the second main grid 115, the overall contact area between the second fine grid 103 and the battery substrate 101 is increased as much as possible, thereby improving the efficiency of the second fine grid 103 in collecting photogenerated carriers in the battery substrate 101.

[0085] In practical applications, along the first direction, the width of the second break filled by the second main grid may be equal to the width of the second break filled by the second pad, that is, the widths of different second breaks on the same second busbar may be the same.

[0086] In some cases, in conjunction with reference Figure 1 and Figure 2 The first fine grid 102 further has a first isolation opening 122 on the second welding area 121; wherein, along the first direction X, the ratio of the width of the first isolation opening 122 for accommodating the second main grid 115 to the width of the second pad 125 is 0.9~1, and the ratio of the width of the first isolation opening 122 for accommodating the second pad 125 to the width of the second pad 125 is 1.6~1.8.

[0087] It is noteworthy that the second current-collecting portion 105 located within the first isolation opening 122 needs to be electrically insulated from the first fine grid 102. Therefore, the width of the first isolation opening 122, which is used to accommodate the second solder pad 125, needs to be smaller than the width of the second solder pad 125. However, for the first isolation opening 122, which is used to accommodate the second busbar 115, the width of the first isolation opening 122 does not need to be larger than the width of the second solder pad 125 to achieve electrical insulation between the second busbar 115 and the first fine grid 102. Therefore, the ratio of the width of the first isolation opening 122, which is designed to accommodate the second busbar 115, to the width of the second solder pad 125 is 0.9-1. This helps to ensure electrical insulation between the second current-collecting portion 105 and the first fine grid 102 while further increasing the overall contact area between the first fine grid 102 and the cell substrate 101, thereby further improving the efficiency of the first fine grid 102 in collecting photogenerated carriers from the cell substrate 101. In addition, the ratio of the width of the first isolation opening 122 designed to accommodate the second pad 125 to the width of the second pad 125 is 1.6~1.8. When the subsequent solder strip contacts and connects with the second pad 125, it is helpful to prevent the insulating glue on the first fine grid 102 from overflowing onto the second pad 125, thereby ensuring good electrical contact between the solder strip and the second pad 125.

[0088] In some examples, along the first direction X, the ratio of the width of the first isolation opening 122 for accommodating the second busbar 115 to the width of the second pad 125 may be 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, or 0.99.

[0089] In some examples, along the first direction X, the ratio of the width of the first isolation opening 122 for accommodating the second pad 125 to the width of the second pad 125 can be 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.7, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78 or 1.79.

[0090] In some cases, in conjunction with reference Figure 1 and Figure 2 The second fine grid 103 also has a second isolation opening 123 on the first welding area 111; wherein, along the first direction X, the ratio of the width of the second isolation opening 123 for accommodating the first main grid 114 to the width of the first pad 124 is 0.9~1, and the ratio of the width of the second isolation opening 123 for accommodating the first pad 124 to the width of the first pad 124 is 1.6~1.8.

[0091] It is worth noting that the first current collector 104 located within the second isolation opening 123 needs to be electrically insulated from the second fine grid 103. Therefore, the width of the second isolation opening 123, which is used to accommodate the first solder pad 124, needs to be smaller than the width of the first solder pad 124. However, the second isolation opening 123, which is used to accommodate the first main grid 114, does not need to be wider than the width of the first solder pad 124 to achieve electrical insulation between the first main grid 114 and the second fine grid 103. Therefore, the ratio of the width of the second isolation opening 123, which is designed to accommodate the first main grid 114, to the width of the first solder pad 124 is 0.9-1. This helps to ensure electrical insulation between the first current collector 104 and the second fine grid 103 while further increasing the overall contact area between the second fine grid 103 and the cell substrate 101, thereby further improving the efficiency of the second fine grid 103 in collecting photogenerated carriers from the cell substrate 101. In addition, the ratio of the width of the second isolation opening 123 designed to accommodate the first solder pad 124 to the width of the first solder pad 124 is 1.6~1.8. When the solder strip is subsequently contacted and connected with the first solder pad 124, it is helpful to prevent the insulating glue located on the second fine grid 103 from overflowing onto the first solder pad 124, thereby ensuring good electrical contact between the solder strip and the first solder pad 124.

[0092] In some examples, along the first direction X, the ratio of the width of the second isolation opening 123 for accommodating the first main gate 114 to the width of the first pad 124 may be 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, or 0.99.

[0093] In some examples, along the first direction X, the ratio of the width of the second isolation opening 123 for accommodating the first pad 124 to the width of the first pad 124 can be 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.7, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78 or 1.79.

[0094] In other embodiments, reference Figure 8 The back contact battery can be a main grid-less battery; the first busbar 104 is a first welding point 154, and each first fine grid 102 is provided with a first welding point 154 at the intersection of the first welding area 111, and the same first welding point 154 is in contact with at least one first fine grid 102; the second busbar 105 is a second welding point 155, and each second fine grid 103 is provided with a second welding point 155 at the intersection of the second welding area 121, and the same second welding point 155 is in contact with at least one second fine grid 103.

[0095] It should be noted that the first welding area 111 can be regarded as the setting area of the first welding point 154, and the second welding area 121 can be regarded as the setting area of the second welding point 155. Figure 8 In the embodiment, a first welding point 154 is in contact with a first fine grid 102, that is, the first welding point 154 is in contact with the first break 112 (refer to Figure 3 ) One-to-one correspondence is only an example. In actual applications, a first welding point may also be contact-connected with at least two first fine grids spaced apart along the second direction. Figure 8 A second welding point 155 is in contact with a second fine grid 103, that is, the second welding point 155 is in contact with the second break 113 (refer to Figure 3 ) is taken as an example. In actual applications, a second welding point can also be contact-connected with at least two second fine grids spaced apart along the second direction.

[0096] To summarize, the first fine grid 102 is designed to have a first break 112 on the first welding region 111, and the cross-sectional area of the first break 112 on the reference plane is designed to gradually increase along the reference direction Z. This helps maximize the volume of the first conduit 104 accommodated within the first break 112, thereby minimizing the height difference between the portion of the first conduit 104 filling the first break 112 and the rest of the portion along the second direction Y. This maximizes the overall flatness of the first conduit 104 and further reduces the amount of material required to prepare the first fine grid 102 while maintaining the contact area between the first fine grid 102 and the battery substrate 101. Furthermore, the first conduit 104 is designed to cover a portion of the top surface of the first fine grid 102 away from the battery substrate 101, ensuring sufficient contact between the first conduit 104 and the first break 112, thereby enhancing the connection strength between the first conduit 104 and the first fine grid 102. Similarly, the second fine grid 103 is designed to have a second break 113 on the second welding region 121, and the cross-sectional area of the second break 113 on the reference surface is designed to gradually increase along the reference direction Z. This helps minimize the height difference between the portion of the second conduit 105 that fills the second break 113 and the rest of the second conduit 105 along the second direction Y, thereby maximizing the overall flatness of the second conduit 105. This also further reduces the amount of material required to fabricate the second fine grid 103 while maintaining the contact area between the second fine grid 103 and the battery substrate 101. Furthermore, the second conduit 105 is designed to cover a portion of the top surface of the second fine grid 103 that is away from the battery substrate 101, ensuring sufficient contact between the second conduit 105 and the second break 113, thereby enhancing the connection strength between the second conduit 105 and the second fine grid 103.

[0097] Secondly, when subsequently establishing contact and connection between the soldering ribbon and the first busbar 104 or the second busbar 105, on the one hand, the extent to which the soldering ribbon on the top surface of the first busbar 104 or the second busbar 105 is pushed out can be significantly reduced, thereby reducing the degree of bending of the soldering ribbon itself and increasing the service life of the soldering ribbon. On the other hand, insulating glue will be subsequently provided on portions of the top surfaces of both the first fine grid 102 and the second fine grid 103. Based on this, the first break 112 can block the insulating glue provided on the first fine grid 102 from further spreading, thereby preventing the insulating glue from being mixed into the junction between the first busbar 104 and the soldering ribbon. The second break 113 can also block the insulating glue provided on the second fine grid 103 from further spreading, thereby preventing the insulating glue from being mixed into the junction between the second busbar 105 and the soldering ribbon.

[0098] Another embodiment of the present disclosure provides a photovoltaic module, comprising a plurality of back-contact cells as provided in the aforementioned embodiment, configured to convert received light energy into electrical energy. It should be noted that for portions identical or corresponding to the aforementioned embodiments, reference may be made to the corresponding descriptions of the aforementioned embodiments and will not be repeated below.

[0099] Combined with reference Figures 1 to 8 ,as well as Figure 9 and Figure 10 The photovoltaic module includes: a cell string formed by connecting multiple back-contact cells 40 provided in the aforementioned embodiments; an encapsulating film 41 for covering the surface of the cell string; and a cover plate 42 for covering the surface of the encapsulating film 41 facing away from the cell string. The back-contact cells 40 are electrically connected in whole or multiple slices to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel. The back-contact cells 40 can be whole cells or sliced cells. A sliced cell refers to a cell formed by cutting a complete whole cell.

[0100] in, Figure 9 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure is shown. Figure 10 for Figure 9 A schematic partial cross-sectional view along the first cross-sectional direction AA1.

[0101] In some embodiments, reference Figure 9 and Figure 10 , multiple back contact cells 40 can be electrically connected through welding ribbons 43. Figure 9 and Figure 10 Only one positional relationship between back-contact cells 40 is illustrated. The grid lines of adjacent back-contact cells 40 may be located on the same side, and the soldering ribbon 43 connects the same side of two adjacent back-contact cells 40. In other embodiments, the grid lines of adjacent back-contact cells may be located on different sides, and the soldering ribbons may respectively connect different sides of two adjacent back-contact cells.

[0102] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, wherein the first encapsulation layer covers one of the front side and the back side of the back-contact cell 40, and the second encapsulation layer covers the other of the front side and the back side of the back-contact cell 40. Specifically, at least one of the first encapsulation layer and the second encapsulation layer can be an organic encapsulation film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulation layer and the second encapsulation layer can also be an EP film, an EPE film, or a PVP film. EP film refers to a coextruded film composed of stacked EVA film and POE film, EPE film refers to a coextruded film formed by stacking EVA film + POE film + EVA film, and PVP film refers to a coextruded film formed by stacking POE film + EVA film + POE film. Coextruded films can be produced by sequentially extruding one or more raw materials onto another pre-existing film during the film processing process, or by bonding different pre-existing films together.

[0103] In some cases, there is a boundary line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0104] In some embodiments, the cover plate 42 may be a light-transmitting cover plate such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may have a concave-convex surface or a velvet surface including multiple raised structures, thereby increasing the utilization of incident light. The cover plate 42 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0105] In some cases, when the back contact cell 40 is a busbar cell, the surface of the back contact cell 40 has a plurality of busbars arranged at intervals along the first direction X and a plurality of fine grids arranged at intervals along the second direction Y. Figure 2 , the main grid includes a first main grid 114 and a second main grid 115; Figure 2 and Figure 9 The fine grid 23 includes a first fine grid 102 and a second fine grid 103. In the process of constructing a cell string using back-contact cells 40, the welding ribbon 43 is electrically connected to at least one busbar on each of two adjacent back-contact cells 40.

[0106] In other cases, when the back contact cell 40 is a main grid-less cell, the surface of the back contact cell 40 has a plurality of sub-grids arranged at intervals along the fifth direction. In the process of constructing a cell string using the back contact cell 40, the welding strip 43 is electrically connected to the plurality of sub-grids on each back contact cell 40 of two adjacent back contact cells 40.

[0107] Those skilled in the art will appreciate that the above-described embodiments are specific examples for implementing the present disclosure, and in actual applications, various changes may be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the scope of protection of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A back contact battery, characterized in that: include: A battery substrate having first welding areas and second welding areas alternately arranged along a first direction; First fine grids and second fine grids are located on the battery substrate and alternately arranged along a second direction, wherein the first fine grids have a first break on the first welding area, and the second fine grids have a second break on the second welding area; a first busbar located in the first welding region, filling the first fracture and covering a portion of the first fine grid away from the top surface of the battery substrate, wherein the first busbar is electrically insulated from the second fine grid; a second busbar located in the second welding region, filling the second fracture and covering a portion of the second fine grid away from the top surface of the battery substrate, wherein the second busbar is electrically insulated from the first fine grid; The direction of the battery substrate pointing toward the first fine grid is a reference direction, and a plane perpendicular to the reference direction is a reference plane. Along the reference direction, the cross-sectional areas of the first fracture and the second fracture on the reference plane tend to gradually increase. The first fine grid includes a plurality of first fine grid branches spaced apart along the first direction, the first fine grid branches having first ends in contact with the first confluence portion, and a thickness of the first ends in the reference direction gradually decreasing in a direction from the first ends to the first confluence portion; The second fine gate includes a plurality of second fine gate branches arranged at intervals along the first direction, the second fine gate branches have a second end portion in contact with the second bus portion, and the thickness of the second end portion in the reference direction gradually decreases along the direction in which the second end portion approaches the second bus portion.

2. The back contact battery according to claim 1, characterized in that The first fine grid further has a first isolation opening on the second welding region for achieving electrical insulation between the first fine grid and the second busbar; the second fine grid further has a second isolation opening on the first welding region for achieving electrical insulation between the second fine grid and the first busbar; A first break or a first isolation opening is formed between two adjacent first fine gate branches along the first direction, and a cross-sectional area of the first end portion on a plane perpendicular to the first direction is gradually reduced along a direction in which the first end portion approaches the first confluence portion. Two adjacent second fine gate branches are spaced apart along the first direction to form a second break or a second isolation opening, and along the direction of the second end portion approaching the second confluence portion, the cross-sectional area of the second end portion on the reference cross section gradually decreases.

3. The back contact battery according to claim 1, characterized in that Along the direction of the first end close to the first confluence, the thickness of the first end in the reference direction decreases by 1um for every 0.05mm length of the first end; and / or, along the direction of the second end close to the second confluence, the thickness of the second end in the reference direction decreases by 1um for every 0.05mm length of the second end.

4. The back contact battery according to claim 1, characterized in that Along the first direction, the ratio of the width of the first fracture to the width of the first confluence is 1 / 3~3 / 4; and / or, along the first direction, the ratio of the width of the second fracture to the width of the second confluence is 1 / 3~3 / 4.

5. The back contact cell according to any one of claims 1 to 4, characterized in that The back contact cell is a main grid cell; The first busbar includes a first main grid, and a plurality of first pads connected to the first main grid and arranged at intervals along the second direction; The second busbar includes a second main grid and a plurality of second pads connected to the second main grid and arranged at intervals along the second direction.

6. The back contact battery according to claim 5, characterized in that Along the first direction, a width of the first break filled by the first main gate is smaller than a width of the first break filled by the first pad; And / or, along the first direction, a width of the second break filled by the second main gate is smaller than a width of the second break filled by the second pad.

7. The back contact battery according to claim 5, characterized in that The first fine grid further has a first isolation opening on the second welding area, and the second fine grid further has a second isolation opening on the first welding area; Among them, along the first direction, the ratio of the width of the first isolation opening for accommodating the second main grid to the width of the second pad is 0.9~1, and the ratio of the width of the first isolation opening for accommodating the second pad to the width of the second pad is 1.6~1.8; and / or, along the first direction, the ratio of the width of the second isolation opening for accommodating the first main grid to the width of the first pad is 0.9~1, and the ratio of the width of the second isolation opening for accommodating the first pad to the width of the first pad is 1.6~1.

8.

8. The back contact cell according to any one of claims 1 to 4, characterized in that The back contact cell is a busbar-less cell; The first confluence portion is a first welding point, and each first fine grid is provided with a first welding point at the intersection with the first welding area, and the same first welding point is in contact with at least one first fine grid; The second confluence portion is a second welding point. A second welding point is provided at the intersection of each second fine grid and the second welding area, and the same second welding point is in contact with and connected to at least one second fine grid.

9. A photovoltaic module, characterized in that: include: A battery string formed by connecting a plurality of back-contact batteries according to any one of claims 1 to 8; A packaging film, used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film facing away from the battery string.

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