Back contact battery and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a back contact battery and a photovoltaic module, and the back contact battery comprises a battery substrate which is provided with a first welding region and a second welding region which are alternately arranged along a first direction; the first fine grid and the second fine grid are located on the battery substrate and are alternately arranged in the second direction, the first fine grid is provided with a first fracture in the first welding area, and the second fine grid is provided with a second fracture in the second welding area; the first confluence part is positioned in the first welding area, fills the first fracture and covers the partial top surface, far away from the battery substrate, of the first fine grid; the second confluence part is positioned in the second welding area, fills the second fracture and covers the partial top surface, far away from the battery substrate, of the second fine grid; the direction, pointing to the first fine grid, of the cell substrate is a reference direction, a plane perpendicular to the reference direction is a reference plane, and the sectional areas of the first fracture and the second fracture on the reference plane are gradually increased in the reference direction, so that the flatness of the first confluence part and the second confluence part is at least improved.

Description

Technical Field

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

[0002] As fossil energy is gradually depleted, photovoltaic cells are increasingly used as a new energy alternative. Photovoltaic cells are devices that convert sunlight into electrical energy. Photovoltaic cells use the principle of photovoltaics to generate carriers, and then use grid lines to lead the carriers out, thereby facilitating the effective use of electrical energy. The grid lines of photovoltaic cells play an important role in collecting and transmitting electrons. When multiple photovoltaic cells are assembled to obtain a photovoltaic module, welding strips are often used to electrically connect the grid lines of adjacent photovoltaic cells.

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

[0004] However, when the contact connection between the soldering ribbon and the bus structure is subsequently achieved, the overlap design based on the bus structure and the fine grid can easily cause the soldering ribbon to bend and different areas to be subjected to uneven force, which can further easily affect the contact stability between the soldering ribbon 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, an embodiment of the present disclosure provides 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 bus; 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 bus; the first fine grid includes a plurality of first fine grid branches arranged at intervals along the first direction, two adjacent first fine grid branches are spaced apart by a first break or a first isolation opening along the first direction, the first fine grid branch has a first end in contact with the first bus, and taking a plane perpendicular to the first direction as a reference section, along the direction of the first end approaching the first bus, the cross-sectional area of ​​the first end on the reference section gradually decreases; the second fine grid includes a plurality of second fine grid branches arranged at intervals along the first direction, two adjacent second fine grid branches are spaced apart by a second break or a second isolation opening along the first direction, the second fine grid branch has a second end in contact with the second bus, and along the direction of the second end approaching the second bus, the cross-sectional area of ​​the second end on the reference section gradually decreases.

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

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

[0010] In some embodiments, along the first direction, the ratio of the width of the first break 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 break 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 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.

[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 are intersected by 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 are intersected by 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, a photovoltaic module is provided, comprising: a battery string, formed by connecting a plurality of back-contact batteries as described in any one of the above items; a packaging film, used to cover the surface of the battery string; and a cover plate, used to cover the surface of the packaging film facing away from the battery string.

[0016] The technical solution provided by the embodiments of the present disclosure has at least the following advantages: First, the first fine grid is designed to have a first break on the first welding area, which is conducive to accommodating the first conduit with the help of the first break, effectively reducing the height difference between the part of the first conduit that fills the first break along the second direction and other parts, thereby facilitating the improvement of the overall flatness of the first conduit, and also facilitating the saving of the amount of material required for preparing the first fine grid. In addition, the first conduit is also designed to cover a portion of the top surface of the first fine grid away from the battery substrate, which is conducive to ensuring that the first conduit is fully in contact with the first break, thereby improving the connection strength between the first conduit and the first fine grid. Further, along the reference direction, the cross-sectional area of ​​the first break on the reference surface is designed to gradually increase, which is conducive to further increasing the volume of the first conduit accommodated in the first break, so as to further reduce the height difference between the part of the first conduit that fills the first break along the second direction and other parts, thereby further improving the overall flatness of the first conduit, and further saving the amount of material required for preparing the first fine grid while ensuring that the contact area between the first fine grid and the battery substrate remains unchanged.

[0017] Similarly, the second fine grid is designed to have a second break on the second welding area, which is conducive to accommodating the second conduit with the help of the second break, effectively reducing the height difference between the part of the second conduit that fills the second break along the second direction and other parts, thereby helping to improve the overall flatness of the second conduit, and also helping to save the amount of material required for preparing the second fine grid. In addition, the second conduit is also designed to cover a portion of the top surface of the second fine grid away from the battery substrate, which is conducive to ensuring that the second conduit is fully in contact with the second break, thereby improving the connection strength between the second conduit and the second fine grid. Further, along the reference direction, the cross-sectional area of ​​the second break on the reference surface is designed to show a trend of gradually increasing, which is conducive to further reducing the height difference between the part of the second conduit that fills the second break along the second direction and other parts, thereby further improving the overall flatness of the second conduit, and while ensuring that the contact area between the second fine grid and the battery substrate remains unchanged, further saving the amount of material required for preparing the second fine grid.

[0018] Secondly, whether it is the matching design of the first fine grid and the first conduit, or the matching design of the second fine grid and the second conduit, when the contact connection between the solder strip and the first conduit or the second conduit is realized later, on the one hand, the degree of the solder strip on the top surface of the first conduit or the second conduit being pushed out can be significantly reduced, so as to reduce the bending degree of the solder strip itself and improve the service life of the solder strip. On the other hand, insulating glue will be set on part of the top surfaces of the first fine grid and the second fine grid later. Based on this, the insulating glue set on the first fine grid can be blocked from spreading further by means of the first break, so as to avoid the phenomenon of the insulating glue being mixed into the junction of the first conduit and the solder strip, for example, to avoid the phenomenon of the solder paste shunting at the junction of the first conduit and the solder strip caused by the insulating glue; the insulating glue set on the second fine grid can be blocked from spreading further by means of the second break, so as to avoid the phenomenon of the insulating glue being mixed into the junction of the second conduit and the solder strip, for example, to avoid the phenomenon of the solder paste shunting at the junction of the second conduit and the solder strip caused by the insulating glue. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, 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 are 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 creative work.

[0020] 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 in one 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 in one embodiment of the present disclosure; Figure 6 A partial top view schematic diagram of a first fine grid and a first busbar in a back contact battery provided by an embodiment of the present disclosure; Figure 7 A partial top view schematic diagram of 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 an embodiment of the present disclosure; Fig. 9 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure; Fig.10 for Fig. 9 A schematic partial cross-sectional view along a first cross-sectional direction AA1. DETAILED DESCRIPTION

[0021] As can be seen from the background art, the design of the bus structure for collecting the current on the fine grid needs further research.

[0022] 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 strip and the bus structure is subsequently achieved, the welding strip located on the bus structure can be regarded as being pushed out relative to the welding strip 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 strip located on the bus structure and the battery substrate to be too large, resulting in a large degree of bending of the welding strip, causing local stress concentration on the battery substrate, prone to battery substrate fragmentation, and affecting the contact stability between the welding strip and the bus structure.

[0023] The present disclosure provides a back-contact cell and photovoltaic module. In the back-contact cell, first, the first fine grid is designed to have a first break on the first welding area, and along the reference direction, the cross-sectional area of ​​the first break on the reference surface tends to gradually increase, which is conducive to increasing the volume of the first conduit contained in the first break as much as possible, so as to reduce the height difference between the part of the first conduit that fills the first break along the second direction and other parts as much as possible, thereby increasing the overall flatness of the first conduit as much as possible, and saving the amount of material required for preparing the first fine grid as much as possible while ensuring that the contact area between the first fine grid and the battery substrate remains unchanged. In addition, the first conduit is also designed to cover a portion of the top surface of the first fine grid away from the battery substrate, which is conducive to ensuring that the first conduit is fully in contact with the first break, thereby improving the connection strength between the first conduit and the first fine grid. Similarly, the second fine grid is designed to have a second break on the second welding area, and along the reference direction, the cross-sectional area of ​​the second break on the reference surface tends to gradually increase, which is conducive to reducing the height difference between the part of the second confluence portion that fills the second break along the second direction and other parts as much as possible, thereby improving the overall flatness of the second confluence portion as much as possible, and further saving the amount of material required for preparing 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 confluence portion is also designed to cover a portion of the top surface of the second fine grid away from the battery substrate, which is conducive to ensuring sufficient contact between the second confluence portion and the second break, thereby improving the connection strength between the second confluence portion and the second fine grid. Secondly, when the contact connection between the welding strip and the first confluence portion or the second confluence portion is subsequently achieved, on the one hand, the degree to which the welding strip located on the top surface of the first confluence portion or the second confluence portion is ejected can be significantly reduced, so as to reduce the bending degree of the welding strip itself and improve the service life of the welding strip. On the other hand, insulating glue will be subsequently set on part of the top surface of the first fine grid and the second fine grid. Based on this, the first break can be used to block the insulating glue set on the first fine grid from further spreading, 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 be used to block the insulating glue set on the second fine grid from further spreading, so as to avoid the phenomenon of insulating glue being mixed into the junction between the second busbar and the welding strip.

[0024] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0025] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0026] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0027] 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).

[0028] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0029] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0030] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component 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 exist between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0031] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as being "on / located 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 exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

[0032] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0033] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the embodiments of the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present disclosure can be implemented.

[0034] An embodiment of the present disclosure provides a back-contact battery, which will be described in detail below with reference to the accompanying drawings.

[0035] Combined with reference Figures 1 to 8, a back contact battery, comprising: a battery substrate 101, the 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 break 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, and along the reference direction Z, the cross-sectional areas of the first break 112 and the second break 113 on the reference plane tend to gradually increase.

[0036] 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 in one 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 in one embodiment of the present disclosure; Figure 6 A partial top view schematic diagram of a first fine grid and a first busbar in a back contact battery provided by an embodiment of the present disclosure; Figure 7 A partial top view schematic diagram of 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.

[0037] In addition, firstly, in order 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 thick solid line, and the second fine grid 103 is indicated by a thin 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.

[0038] 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.

[0039] 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 confluence 104 fills the first break 112 to achieve contact connection between the first confluence 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 confluence 104 with the help of the first break 112, and avoid overlapping of the first confluence 104 with the first break 112 as much as possible, thereby effectively reducing the height difference between the part 134 and the other part 144 of the first confluence 104 along the second direction Y that fills the first break 112, which is beneficial to improve the overall flatness of the first confluence 104, and also beneficial to saving the amount of material required to prepare the first fine grid 102. In addition, the first convergence portion 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 convergence portion 104 and the first break 112. In other words, it is ensured that the first convergence portion 104 fills the first break 112 to ensure sufficient contact area between the first convergence portion 104 and the first fine grid 102, thereby improving the connection strength between the first convergence portion 104 and the first fine grid 102, and effectively avoiding the problem of poor contact between the first convergence portion 104 and the first fine grid 102, and improving the fault tolerance rate when forming the first convergence portion 104. Furthermore, along the reference direction Z, the cross-sectional area of ​​the first break 112 on the reference plane is designed to show a gradually increasing trend, which is beneficial to increasing the volume of the first break 112 by gradually increasing the opening degree of the first break 112, so as to further increase the volume of the first confluence 104 that can be accommodated in the first break 112, so as to further reduce the height difference between the part of the first confluence 104 that fills the first break 112 and other parts along the second direction Y. In other words, more parts of the first confluence 104 are in the same layer with 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.

[0040] In some cases, taking the top surface of the first fine grid 102 away from the battery substrate 101 as a reference plane, along the reference direction Z, compared with the height difference between the first conduit and the first fine grid when the two are overlapped, the height difference between the top surface of the first conduit 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 convergence portion and the first fine grid when they are overlapped is about 7um~8um. In the first convergence portion 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 convergence portion 104 away from the battery substrate 101 and the reference plane can be reduced by about 2um~3um on the basis of 7um~8um.

[0041] Similarly, the second fine gate 103 is designed to have a second break 113 on the second welding area 121, so that the second convergence part 105 fills the second break 113 to achieve contact connection between the second convergence part 105 and the second fine gate 103, so as to collect currents on multiple second fine gates 103, which is beneficial to accommodate the second convergence part 105 with the help of the second break 113 and avoid overlapping of the second convergence part 105 with the second break 113 as much as possible, thereby effectively reducing the height difference between the part 135 and the other part 145 of the second convergence part 105 along the second direction Y that fills the second break 113, which is beneficial to improve the overall flatness of the second convergence part 105 and save the amount of material required to prepare the second fine gate 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, and 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 break 113 on the reference plane is designed to show a gradually increasing trend, which is beneficial to increasing the volume of the second break 113 by gradually increasing the opening degree of the second break 113, so as to further increase the volume of the second confluence 105 that can be accommodated in the second break 113, so as to further reduce the height difference between the part of the second confluence 105 that fills the second break 113 and other parts along the second direction Y. In other words, more parts of the second confluence 105 are in the same layer with the second fine grid 103 along the second direction Y, thereby further improving the overall flatness of the second confluence 105, and further saving the amount of 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.

[0042] In some cases, taking the top surface of the second fine grid 103 away from the battery substrate 101 as a reference plane, along the reference direction Z, compared with the height difference between the second busbar and the second fine grid when they 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 about 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 about 2um~3um on the basis of 7um~8um.

[0043] It is worth noting that, regardless of 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 fact that the overall flatness of both the first convergence part 104 and the second convergence part 105 is 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 broken. 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 the partial top surfaces of the first fine grid 102 and the second fine grid 103 later. 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 penetrated first fine grid 102. In other words, the first break 112 is used to block the insulating glue set on the first fine grid 102 from further spreading, so as to avoid the phenomenon of the 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 shunted 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 shunted at the junction of the first confluence 104 and the solder strip, so as to prevent the insulating glue from shunting the solder paste at the junction of the first confluence 104 and the solder strip. 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 that the insulating glue is mixed into the junction between the second busbar 105 and the soldering strip, for example, to avoid the insulating glue from causing the solder paste to be shunted 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.

[0044] It should be noted that Figure 6The dotted line in the figure demarcates the portion 134 and other portions 144 of the first confluence portion 104 filled with the first break 112 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 regarded as the portion of the first confluence portion 104 directly facing the first fine grid 102 along the first direction X, and the other portions 144 of the first confluence portion 104 can be regarded 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 and other portions 144 of the first confluence portion 104 filled with the first break 112 can be effectively reduced, and even there can be no height difference between the portion 134 and other portions 144 of the first confluence portion 104 filled with the first break 112.

[0045] also, Figure 7 The dotted line in the figure demarcates a portion 135 of the second confluence portion 105 filled with the second break 113 and other portions 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 regarded as a portion of the second confluence portion 105 directly facing the second fine grid 103 along the first direction X, and other portions 145 of the second confluence portion 105 can be regarded as a portion of the second confluence portion 105 not directly facing the second fine grid 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 other portions 145 can be effectively reduced, and even there can be no height difference between the portion 135 of the second confluence portion 105 filled with the second break 113 and other portions 145.

[0046] The back contact battery provided by one embodiment of the present disclosure is described in detail below.

[0047] 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 for achieving electrical insulation between the first fine grid 102 and the second bus 105 ; the second fine grid 103 also has a second isolation opening 123 on the first welding area 111 for achieving electrical insulation between the second fine grid 103 and the first bus 104 .

[0048] 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 fact that the first welding area 111 and the second welding area 121 are alternately arranged along the first direction X, the first break 112 and the first isolation opening 122 on the same first fine grid 102 are also alternately arranged 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 fact that the first welding area 111 and the second welding area 121 are alternately arranged along the first direction X, the second break 113 and the second isolation opening 123 on the same second fine grid 103 are also alternately arranged along the first direction X.

[0049] 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, and 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 132a in contact with the first confluence portion 104. Taking the plane perpendicular to the first direction X as the reference section, along the direction of the first end 132a approaching the first confluence portion 104, the cross-sectional area of ​​the first end 132a on the reference section gradually decreases, which is beneficial to ensure that the cross-sectional area of ​​the first break 112 on the reference plane tends to gradually increase along the reference direction Z.

[0050] It is worth noting that the first fine gate 102 can be regarded as being sequentially divided into multiple sections by the first break 112 and the first isolation opening 122, each section can be regarded as a first fine gate branch 132, and the end of the first fine gate branch 132 used to form the first break 112 is the first end 132a. Moreover, for two adjacent first fine gate branches 132 along the first direction X, the directions of the first end 132a approaching the first confluence portion 104 can be opposite.

[0051] It should be noted that, except for the first fine grid branch 132 located on the edge of the battery substrate 101, the other first fine grid branches 132 have both the first end 132a for forming the first break 112 and the end (not marked in the figure) for forming the first isolation opening 122. In addition, the cross-sectional area of ​​the end of the first fine grid branch 132 for forming the first isolation opening 122 on the reference cross section can change gradually like the first end 132a, or can remain unchanged. In other words, the cross-sectional area of ​​the end of the first fine grid branch 132 for forming the first isolation opening 122 on the reference cross section can be flexibly designed according to actual needs.

[0052] In some examples, in conjunction with reference Figure 1 , Figures 3 to 5 The first conduit 104 covers the top surface of the first end 132a away from the battery substrate 101, and the contact surface between the first conduit 104 and the first end 132a can be a whole curved surface, for example, the whole curved surface can be similar to the curved surface of half a bullet head.

[0053] 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, two adjacent second fine gate branches 133 being spaced apart along the first direction X to form a second break 113 or a second isolation opening 123, the second fine gate branch 133 having a second end 133a in contact with the second confluence portion 105, and a cross-sectional area of ​​the second end 133a on the reference cross-section gradually decreases in a direction where the second end 133a approaches the second confluence portion 105, which is beneficial to ensure that the cross-sectional area of ​​the second break 113 on the reference plane tends to gradually increase along the reference direction Z.

[0054] It is worth noting that the second fine gate 103 can be regarded as being sequentially divided into multiple sections by the second break 113 and the second isolation opening 123, each section can be regarded as a second fine gate branch 133, and the end of the second fine gate branch 133 used to form the second break 113 is the second end 133a. Moreover, for two second fine gate branches 133 adjacent to each other in the first direction X, the directions in which the second end 133a approaches the second confluence portion 105 can be opposite.

[0055] It should be noted that, except for the second fine grid branch 133 located on the edge of the battery substrate 101, the other second fine grid branches 133 have both the second end 133a for forming the second break 113 and the end (not marked in the figure) for forming the second isolation opening 123. In addition, the cross-sectional area of ​​the end of the second fine grid branch 133 for forming the second isolation opening 123 on the reference cross section can change gradually like the second end 133a, or can remain unchanged. In other words, the cross-sectional area of ​​the end of the second fine grid branch 133 for forming the second isolation opening 123 on the reference cross section can be flexibly designed according to actual needs.

[0056] In some examples, in conjunction with reference Figure 1 , Figures 3 to 5 The second conduit 105 covers the top surface of the second end 133a away from the battery substrate 101, and the contact surface between the second conduit 105 and the second end 133a can be a whole curved surface, for example, a whole curved surface can be similar to a half bullet head curved surface.

[0057] 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 may gradually decrease to form a first fracture 112 whose cross-sectional area on the reference surface gradually increases 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 be gradually reduced to form a second fracture 113 whose cross-sectional area on the reference plane tends to gradually increase along the reference direction Z.

[0058] It should be noted that, in order to ensure that the cross-sectional area of ​​the first fracture 112 on the reference plane tends to gradually increase along the reference direction Z, along the direction of the first end 132a close to 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 also the width of the first end 132a in the second direction Y can be designed to gradually decrease; in order to ensure that the cross-sectional area of ​​the second fracture 113 on the reference plane tends to gradually increase along the reference direction Z, along the direction of the second end 133a close to 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 also the width of the second end 133a in the second direction Y can be designed to gradually decrease.

[0059] In some examples, reference Figure 4 , along the direction in which the first end portion 132 a approaches the first conduit 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.

[0060] In some examples, reference Figure 5 , along the direction of the second end portion 133 a approaching the second conduit 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.

[0061] 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.

[0062] In some embodiments, reference Figure 4, along 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, can be 0.35, 0.38, 0.4, 0.42, 0.45, 0.48, 0.5, 0.53, 0.55, 0.6, 063, 0.65, 0.66, 0.7 or 0.72, etc. It should be noted that, whether the back contact cell is a back contact cell with a main grid or a back contact cell without a main grid, 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.

[0063] In some examples, the width W1 of the first break 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.

[0064] 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 confluence portion 105 can be 1 / 3 to 3 / 4, for example, can be 0.35, 0.38, 04, 042, 0.45, 0.48, 0.5, 0.53, 0.55, 0.6, 063, 0.65, 0.66, 0.7 or 0.72, etc. It should be noted that, whether the back contact cell is a back contact cell with a main grid or a back contact cell without a main grid, the ratio of the width W3 of the second break 113 to the width W4 of the second confluence portion 105 can be 1 / 3 to 3 / 4.

[0065] In some examples, the width W3 of the second break 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.

[0066] 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.

[0067] The back contact cell with a main grid and the back contact cell without a main grid are described in detail below.

[0068] 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 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 pads 125 that are in contact with the second main grid 115 and arranged at intervals along the second direction Y.

[0069] 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 convergence part 104, and the first welding area 111 can be regarded as the setting area of ​​the first main gate 114 and the first pads 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 convergence part 105, and the second welding area 121 can be regarded as the setting area of ​​the second main gate 115 and the second pads 125.

[0070] In the first fine grid 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 grid 114 to accommodate the first main grid 114 and avoid overlapping of the first main grid 114 and the first fine grid 102, thereby effectively reducing the height difference between the portion of the first main grid 114 filled with the first break 112 along the second direction Y and other portions, so as to improve the overall flatness of the first main grid 114; but also a first break 112 is also 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 grid 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, so as to improve the overall flatness of the first solder pad 124.

[0071] 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, so as to improve 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 soldering pad 125 to accommodate the second soldering pad 125 and avoid overlapping of the second soldering pad 125 and the second fine gate 103, thereby effectively reducing the height difference between the portion of the second soldering pad 125 filled with the second break 113 and other portions along the second direction Y, so as to improve the overall flatness of the second soldering pad 125.

[0072] 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 main grid 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 for accommodating the same first confluence portion 104 may be different based on whether the first main grid 114 or the first pad 124 is accommodated. It is worth noting that in order to ensure the alignment accuracy and sufficient contact area between the subsequent solder strip and the first confluence portion 104, along the first direction X, the width of the first main grid 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 can be increased as much as possible, thereby improving the first fine grid 102 The efficiency of collecting photogenerated carriers in the battery substrate 101.

[0073] 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.

[0074] 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 main grid 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 be different based on whether the second main grid 115 or the second pad 125 is accommodated. It is worth noting that in order to ensure the 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 main grid 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 in 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 second fine grid 103 The efficiency of collecting photogenerated carriers in the battery substrate 101 is improved.

[0075] 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.

[0076] In some cases, in conjunction with reference Figure 1 and Figure 2 The first fine grid 102 also 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.

[0077] It is worth noting that, for the second busbar 105, the second busbar 105 located in the first isolation opening 122 needs to be electrically insulated from the first fine grid 102, and thus the width of the first isolation opening 122 for accommodating the second pad 125 needs to be smaller than the width of the second pad 125. However, for the first isolation opening 122 for accommodating the second main grid 115, it is not necessary to design the width of the first isolation opening 122 for accommodating the second main grid 115 to be larger than the width of the second pad 125, so that the electrical insulation between the second main grid 115 and the first fine grid 102 can be achieved. Based on this, the ratio of the width of the first isolation opening 122 designed to accommodate the second main grid 115 to the width of the second pad 125 is 0.9-1, which is conducive to further increasing the contact area between the first fine grid 102 and the battery substrate 101 while ensuring the electrical insulation between the second busbar 105 and the first fine grid 102, so as to further improve the efficiency of the first fine grid 102 in collecting photogenerated carriers in the battery 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 is in contact with the second pad 125, it is helpful to prevent the insulating glue located 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.

[0078] In some examples, along the first direction X, the ratio of the width of the first isolation opening 122 for accommodating the second main gate 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, etc.

[0079] 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.

[0080] 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.

[0081] It is worth noting that, for the first current confluence portion 104, the first current confluence portion 104 located in the second isolation opening 123 needs to be electrically insulated from the second fine grid 103, and thus the width of the second isolation opening 123 for accommodating the first pad 124 needs to be smaller than the width of the first pad 124. However, for the second isolation opening 123 for accommodating the first main grid 114, it is not necessary to design the width of the second isolation opening 123 for accommodating the first main grid 114 to be larger than the width of the first pad 124, so that the electrical insulation between the first main grid 114 and the second fine grid 103 can be achieved. Based on this, the ratio of the width of the second isolation opening 123 designed to accommodate the first main grid 114 to the width of the first pad 124 is 0.9 to 1, which is conducive to further increasing the contact area between the second fine grid 103 and the battery substrate 101 while ensuring the electrical insulation between the first current confluence portion 104 and the second fine grid 103, so as to further improve the efficiency of the second fine grid 103 in collecting photogenerated carriers in the battery 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, which is helpful to prevent the insulating glue located on the second fine grid 103 from overflowing onto the first solder pad 124 when the solder strip is subsequently contacted and connected with the first solder pad 124, thereby ensuring good electrical contact between the solder strip and the first solder pad 124.

[0082] 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.

[0083] 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.

[0084] 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 with 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 with the second welding area 121, and the same second welding point 155 is in contact with at least one second fine grid 103.

[0085] 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. In addition, 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 ) is an example of one-to-one correspondence. In practical 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 of one-to-one correspondence. In actual applications, a second welding point can also be contact-connected with at least two second fine grids arranged at intervals along the second direction.

[0086] In summary, firstly, the first fine grid 102 is designed to have a first break 112 on the first welding area 111, and along the reference direction Z, the cross-sectional area of ​​the first break 112 on the reference surface is designed to gradually increase, which is conducive to increasing the volume of the first conduit 104 contained in the first break 112 as much as possible, so as to reduce the height difference between the part of the first conduit 104 filled with the first break 112 and other parts along the second direction Y as much as possible, thereby increasing the overall flatness of the first conduit 104 as much as possible, and further saving the amount of material required for preparing the first fine grid 102 while ensuring that the contact area between the first fine grid 102 and the battery substrate 101 remains unchanged. In addition, the first conduit 104 is also designed to cover a part of the top surface of the first fine grid 102 away from the battery substrate 101, which is conducive to ensuring that the first conduit 104 is fully in contact with the first break 112, thereby improving 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 area 121, and along the reference direction Z, the cross-sectional area of ​​the second break 113 on the reference surface is designed to gradually increase, which is conducive to reducing the height difference between the part of the second confluence 105 filled with the second break 113 and other parts along the second direction Y as much as possible, thereby improving the overall flatness of the second confluence 105 as much as possible, and further saving the amount of 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. In addition, the second confluence 105 is also 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 that the second confluence 105 is fully in contact with the second break 113, thereby improving the connection strength between the second confluence 105 and the second fine grid 103.

[0087] Secondly, when the contact connection between the welding strip and the first busbar 104 or the second busbar 105 is realized later, on the one hand, the degree of the welding strip on the top surface of the first busbar 104 or the second busbar 105 being pushed out can be significantly reduced, so as to reduce the bending degree of the welding strip itself and improve the service life of the welding strip. On the other hand, insulating glue will be set on the top surfaces of the first fine grid 102 and the second fine grid 103 later. Based on this, the insulating glue set on the first fine grid 102 can be blocked from spreading further with the help of the first break 112, so as to avoid the phenomenon of the insulating glue being mixed into the junction between the first busbar 104 and the welding strip; the insulating glue set on the second fine grid 103 can be blocked from spreading further with the help of the second break 113, so as to avoid the phenomenon of the insulating glue being mixed into the junction between the second busbar 105 and the welding strip.

[0088] Another embodiment of the present disclosure further provides a photovoltaic module, which includes a plurality of back-contact cells as provided in the above embodiment, and the photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same or corresponding to the above embodiment can refer to the corresponding description of the above embodiment, and will not be repeated below.

[0089] Combined with reference Figures 1 to 8 ,as well as Fig. 9 and Fig.10 The photovoltaic module includes: a battery string, which is formed by connecting multiple back-contact batteries 40 provided in the above embodiments; a packaging film 41, which is used to cover the surface of the battery string; and a cover plate 42, which is used to cover the surface of the packaging film 41 away from the battery string. The back-contact battery 40 is electrically connected in the form of a whole piece or multiple pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel. The back-contact battery 40 can be a whole cell or a sliced ​​cell. A sliced ​​cell refers to a cell formed by a complete whole cell through a cutting process.

[0090] in, Fig. 9 A partial three-dimensional schematic diagram of a photovoltaic assembly provided by another embodiment of the present disclosure, Fig.10 for Fig. 9 A schematic partial cross-sectional view along a first cross-sectional direction AA1.

[0091] In some embodiments, reference Fig. 9 and Fig.10 , multiple back contact cells 40 can be electrically connected via solder strips 43 . Fig. 9 and Fig.10 Only one positional relationship between the back contact cells 40 is illustrated, and the grid lines of the adjacent multiple back contact cells 40 may be located on the same side, so that the welding strip 43 connects the same side of two adjacent back contact cells 40. In other embodiments, the grid lines of the adjacent multiple back contact cells may also be located on different sides, so that the welding strips respectively connect different sides of two adjacent back contact cells.

[0092] 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 or the back side of the back contact battery 40, and the second encapsulation layer covers the other of the front side or the back side of the back contact battery 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer may be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer may also be an EP film, an EPE film, or a PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. The co-extruded film can be prepared by sequentially extruding one or more raw materials onto another already made film during the film processing process, or bonding different types of already made films together.

[0093] In some cases, there is a boundary 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.

[0094] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface or a velvet surface including a plurality of convex structures, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0095] In some cases, when the back contact cell 40 is a main grid cell, the surface of the back contact cell 40 has a plurality of main grids 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; combined with reference Figure 2 and Fig. 9 The fine grid 23 includes a first fine grid 102 and a second fine grid 103. In the process of constructing a battery string using back-contact batteries 40, the welding ribbon 43 is electrically connected to at least one main grid on each back-contact battery 40 of two adjacent back-contact batteries 40.

[0096] In other cases, when the back contact cell 40 is a main grid-free 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.

[0097] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can 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 can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope 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, wherein the battery substrate has first welding areas and second welding areas alternately arranged along a first direction; A first fine grid and a second fine grid located on the battery substrate and arranged alternately 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 busbar located in the first welding area fills the first break and covers a portion of the first fine grid away from the top surface of the battery substrate, the first busbar being electrically insulated from the second fine grid; A second busbar located in the second welding area fills the second break and covers a portion of the second fine grid away from the top surface of the battery substrate, and the second busbar is electrically insulated from the first fine grid; The direction from the battery substrate 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 fracture and the second fracture on the reference plane tend to increase gradually.

2. The back contact cell according to claim 1, characterized in that: 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 comprises a plurality of first fine grid branches arranged at intervals along the first direction, two adjacent first fine grid branches are spaced apart along the first direction to form a first break or a first isolation opening, the first fine grid branch has a first end portion in contact with and connected to the first confluence portion, and a plane perpendicular to the first direction is taken as a reference cross section, and along a direction in which the first end portion approaches the first confluence portion, a cross-sectional area of ​​the first end portion on the reference cross section gradually decreases; The second fine gate includes a plurality of second fine gate branches arranged at intervals along the first direction, and two adjacent second fine gate branches are separated by a second break or a second isolation opening along the first direction, and the second fine gate branch has a second end portion in contact with and connected to the second conduit, and along the direction in which the second end portion approaches the second conduit, the cross-sectional area of ​​the second end portion on the reference section gradually decreases.

3. The back contact battery according to claim 2, characterized in that: Along the direction in which the first end portion approaches the first confluence portion, the thickness of the first end portion in the reference direction gradually decreases; Along a direction in which the second end portion approaches the second confluence portion, a thickness of the second end portion in the reference direction gradually decreases.

4. The back contact cell according to claim 3, 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; 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.

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

6. The back contact cell according to any one of claims 1 to 5, 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 that are in contact with the first main grid and are 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 the second main grid and are arranged at intervals along the second direction.

7. The back contact cell according to claim 6, characterized in that: 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, 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.

8. The back contact cell according to claim 6, 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.

9. The back contact cell according to any one of claims 1 to 5, characterized in that The back contact cell is a busbar-free cell; The first confluence portion is a first welding point, and each intersection of the first fine grid and the first welding area is provided with a first welding point, and the same first welding point is in contact and connected with at least one first fine grid; The second confluence portion is a second welding point. A second welding point is disposed at the intersection of each of the second fine grids and the second welding area, and the same second welding point is in contact with and connected to at least one of the second fine grids.

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

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