Battery piece, photovoltaic module and glue printing screen printing plate

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a battery piece, a photovoltaic module and a glue printing screen printing plate, the battery piece comprises a substrate, the substrate comprises two edge areas arranged along a first direction and a central area located in the middle of the edge areas; the multiple rows of glue point structures are arranged in the first direction, each row of glue point structures comprises a plurality of glue points arranged at intervals in the second direction, and the glue points in each row of glue point structures are used for being in fixed contact with the same welding strip; wherein the total area of orthographic projections of all the glue points in each row of edge glue point structures on the surface of the substrate is larger than the total area of orthographic projections of all the glue points in each row of center glue point structures on the surface of the substrate, and in the first direction, the length of the glue points in the edge glue point structures is larger than or equal to the length of the glue points in the center glue point structures, and / or the length of the glue points in the center glue point structures is larger than or equal to the length of the glue points in the center glue point structures. In the second direction, the width of the glue points in the edge glue point structures is larger than or equal to the width of the glue points in the center glue point structure, and the reliability of the battery piece can be improved.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a battery cell, a photovoltaic module and a printing screen. Background Art

[0002] Photovoltaic modules are components that use the photovoltaic effect to generate electricity. They are usually composed of cells, films, glass, and cover plates. Cells are an important component of the main components. The welding performance of cells at the component end directly affects the power generation performance and power of the component.

[0003] 0BB (no main grid) technology eliminates the main grid line at the battery end, leaving only thin grid lines, connecting the solder strip to the battery cell by gluing, and then fusing by lamination. Therefore, 0BB technology can reduce the consumption of silver paste while increasing the light-receiving area of ​​the battery, reducing optical loss, and effectively increasing the power of the module. In addition, the design of the battery without pad points and main grid makes the battery surface color more uniform and beautiful, which is one of the solutions that the industry is constantly seeking for technological breakthroughs.

[0004] Currently, it is necessary to provide a battery cell to increase the reliability of the connection between the battery cell and the welding ribbon. Summary of the invention

[0005] The embodiments of the present disclosure provide a battery cell, a photovoltaic module, and an offset printing screen, which can at least improve the reliability of the connection between the battery cell and the welding ribbon.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a battery cell, comprising: a substrate, the substrate comprising two edge areas arranged along a first direction and a central area located in the middle of the edge areas; multiple rows of glue dot structures arranged along the first direction, each row of the glue dot structures comprising multiple glue dots arranged at intervals along a second direction, and the glue dots in each row of the glue dot structures being used for fixed contact with the same welding strip; wherein the multiple rows of glue dot structures include at least one row of edge glue dot structures located in each of the edge areas, and also include at least one row of central glue dot structures located in the central area, the total area of ​​the orthographic projection of all the glue dots in each row of the edge glue dot structures on the substrate surface is greater than the total area of ​​the orthographic projection of all the glue dots in each row of the central glue dot structures on the substrate surface, and in the first direction, the length of the glue dots in the edge glue dot structures is greater than or equal to the length of the glue dots in the central glue dot structures, and / or, in the second direction, the width of the glue dots in the edge glue dot structures is greater than or equal to the width of the glue dots in the central glue dot structures.

[0007] In some embodiments, the edge glue dot structure is in multiple rows, and in the direction from the edge area to the center area, the areas of the positive projections of all the glue dots in the edge glue dot structure on the substrate surface tend to increase.

[0008] In some embodiments, the number of the glue dots in the edge glue dot structure is greater than the number of the glue dots in the center glue dot structure.

[0009] In some embodiments, the edge glue dot structures are in multiple rows, the center glue dot structures are in multiple rows, and the spacing between adjacent edge glue dot structures is smaller than the spacing between adjacent center glue dot structures.

[0010] In some embodiments, the substrate includes a first side and a second side arranged along the second direction, and in the same row of the glue dot structures, the length of the glue dot close to the second side is greater than the length of the glue dot close to the first side.

[0011] In some embodiments, the substrate includes a first side and a second side arranged along the second direction, and an arrangement density of the glue dots near the second side is greater than an arrangement density of the glue dots near the first side.

[0012] In some embodiments, along the second direction, the width of the glue point structure located in the edge area away from the central area is greater than the width of the glue point structure located in the edge area close to the central area.

[0013] In some embodiments, the base includes a first side and a second side arranged along the second direction, a portion of the glue dots located in the center area close to the first side are aligned along the first direction, a portion of the glue dots located in the center area close to the second side are aligned along the first direction, and the remaining glue dots that are in the same column along the first direction and located in the center area are staggered with each other.

[0014] According to some embodiments of the present disclosure, on the other hand, a photovoltaic module is provided, including: a battery string, which is formed by connecting a plurality of battery cells as described above; a packaging film, which is used to cover the surface of the battery string; and a cover plate, which is used to cover the surface of the packaging film away from the battery string.

[0015] According to some embodiments of the present disclosure, the embodiments of the present disclosure further provide a printing glue screen for dispensing glue on solar cells, comprising: a main body, the main body comprising two first areas arranged along a first direction and a second area located in the middle of the first areas; a plurality of rows of dispensing glue mesh structures arranged along the first direction, each row of the dispensing glue mesh structures comprising a plurality of through holes arranged at intervals along a second direction, and glue is printed on the surface of the solar cell through the through holes; wherein the plurality of rows of dispensing glue mesh structures comprise at least one row of edge mesh structures located in each of the first areas, and also comprise at least one row of center mesh structures located in the second area, the total area of ​​the orthographic projection of all the through holes in each row of the edge mesh structures on the main body surface is greater than the total area of ​​the orthographic projection of all the through holes in each row of the center mesh structures on the main body surface, and in the first direction, the length of the through holes in the edge mesh structure is greater than or equal to the length of the through holes in the center mesh structure, and / or, in the second direction, the width of the through holes in the edge mesh structure is greater than or equal to the width of the through holes in the center mesh structure.

[0016] The technical solution provided by the embodiment of the present disclosure has at least the following advantages: for the edge area of ​​the battery cell, the edge area is more prone to the situation where the solder strip and the battery cell fall off. Therefore, the embodiment of the present disclosure sets the total area of ​​all glue points in each row of the edge glue point structure to be larger than the sum of the total areas of all glue points in each row of the central glue point structure, so that the contact area between the edge glue point structure and the solder strip can be increased, thereby improving the connection reliability between the solder strip in the edge area and the battery cell. Moreover, the present disclosure also sets the through hole length of the edge mesh structure to be not less than the through hole length in the central mesh structure, and / or the width of the edge mesh structure to be not less than the width of the through hole in the central mesh structure, so that in the first direction and / or the second direction, the contact length and / or contact width between the solder strip and each glue point will not be reduced, thereby avoiding affecting the connection reliability between the solder strip and each glue point. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] Figure 1 A top view of a battery cell is provided for one embodiment of the present disclosure;

[0019] Figure 2 Another top view of a battery cell provided in one embodiment of the present disclosure;

[0020] Figure 3 A schematic diagram of the structure of a photovoltaic module provided by an embodiment of the present disclosure;

[0021] Figure 4 A cross-sectional view of a photovoltaic module provided in one embodiment of the present disclosure;

[0022] Figure 5 A schematic structural diagram of an offset printing screen provided in one embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] From the background technology, it can be seen that the use of main grid connection lines and welding pads is eliminated in 0BB technology, resulting in reduced welding reliability between the welding ribbon and the battery cell, especially in the edge area of ​​the battery cell. When printing glue dots in the edge area of ​​the battery cell, printing omissions may occur, resulting in the edge area of ​​the battery cell being the main area where the connection between the welding ribbon and the battery cell fails.

[0024] The present disclosure provides a battery cell, a photovoltaic module and a printing glue screen. In the battery cell, the edge area of ​​the battery cell is more likely to cause the soldering tape to fall off from the battery cell. Therefore, in the embodiment of the present disclosure, the total area of ​​all the glue points in each row of the edge glue point structure is larger than the sum of the total areas of all the glue points in each row of the center glue point structure, so that the contact area between the edge glue point structure and the soldering tape can be increased, thereby improving the connection reliability between the soldering tape in the edge area and the battery cell. Moreover, the present disclosure also sets the through hole length of the edge mesh structure to be not less than the through hole length in the center mesh structure, and / or the width of the edge mesh structure to be not less than the width of the through hole in the center mesh structure, so that in the first direction and / or the second direction, the contact length and / or contact width between the soldering tape and each glue point will not be reduced, thereby avoiding affecting the connection reliability between the soldering tape and each glue point.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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).

[0029] 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.

[0030] 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.

[0031] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a 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 be present 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.

[0032] 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, a film, a region, or a 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, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0033] 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.

[0034] 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 present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can be implemented.

[0035] refer to Figure 1 , Figure 1 A top view of a battery cell is provided for one embodiment of the present disclosure.

[0036] In some embodiments, the battery cell may include: a substrate 100 , wherein the substrate 100 includes two edge regions 110 arranged along a first direction X and a central region 120 located between the edge regions 110 .

[0037] The battery cell may further include: a plurality of rows of glue point structures 101 arranged along the first direction X, each row of glue point structures 101 including a plurality of glue points 111 arranged at intervals along the second direction Y, and the glue points 111 in each row of glue point structures 101 are used to be fixedly contacted with the same soldering ribbon 102 .

[0038] Among them, the multi-row glue dot structure 101 includes at least one row of edge glue dot structures 121 located in each edge area 110, and also includes at least one row of central glue dot structures 131 located in the central area 120, the total area of ​​the orthographic projection of all glue dots 111 in each row of edge glue dot structures 121 on the surface of the substrate 100 is greater than the total area of ​​the orthographic projection of all glue dots 111 in each row of central glue dot structures 131 on the surface of the substrate 100, and in the first direction X, the length of the glue dots 111 in the edge glue dot structure 121 is greater than or equal to the length of the glue dots 111 in the central glue dot structure 131, and / or, in the second direction Y, the width of the glue dots 111 in the edge glue dot structure 121 is greater than or equal to the width of the glue dots 111 in the central glue dot structure 131.

[0039] In the battery cell, for the edge area 110 of the battery cell, the edge area 110 is more likely to cause the welding tape 102 to fall off from the battery cell. Therefore, in the embodiment of the present disclosure, the total area of ​​all glue points 111 in each row of edge glue point structure 121 is set to be greater than the sum of the total areas of all glue points 111 in each row of central glue point structure 131, so that the contact area between the edge glue point structure 121 and the welding tape 102 can be increased, thereby improving the connection reliability between the welding tape 102 in the edge area 110 and the battery cell. In addition, the present disclosure also sets the length of the through hole 211 of the edge mesh structure 221 to be not less than the length of the through hole 211 in the central mesh structure 231, and / or the width of the edge mesh structure 221 is not less than the width of the through hole 211 in the central mesh structure 231, so that in the first direction X and / or the second direction Y, the contact length and / or contact width between the welding tape 102 and each glue point 111 will not be reduced, thereby avoiding affecting the connection reliability between the welding tape 102 and each glue point 111.

[0040] In some embodiments, the cell includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter Rear Cell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology heterojunction cells), solar thin-film cells, and stacked cells. Among them, solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. Stacked cells include, but are not limited to, perovskite cells superimposed on crystalline silicon cells, perovskite cells superimposed on perovskite cells, and perovskite cells superimposed on thin-film cells.

[0041] Depending on the type of battery cell, the substrate 100 may have a corresponding structure. Taking the TOPCon battery as an example, the substrate 100 of the battery cell may be a substrate 100 that has formed a front emitter, a front passivation layer, a front electrode, a back oxide layer, a back doped conductive layer, a back passivation layer and a back electrode.

[0042] For the edge area 110 and the center area 120, the edge area 110 may be a region where 1 / 5 of the edge of the substrate 100 is located along the first direction X, and the center area 120 may be a region where 3 / 5 of the center of the substrate 100 is located along the first direction X. In other embodiments, the edge area 110 and the center area 120 may also be other proportions, and the area of ​​the substrate 100 included in the edge area 110 and the center area 120 may be set according to requirements.

[0043] For the glue dot structure 101, the glue dot structure 101 can be a printed conductive glue or an insulating glue. When the glue dot structure 101 is a conductive glue, the total area of ​​the true projection of the edge glue dot structure 121 on the surface of the substrate 100 is set to be larger, so that the contact resistance between the soldering strip 102 in the edge area 110 of the substrate 100 and the glue dot structure 101 can be reduced, thereby reducing the transmission loss of carriers in the edge area 110; when the glue dot structure 101 is an insulating glue, the total area of ​​the true projection of the edge glue dot structure 121 on the surface of the substrate 100 is set to be larger, so that the reliability of the connection between the soldering strip 102 in the edge area 110 of the substrate 100 and the glue dot structure 101 can be increased, thereby avoiding abnormalities such as the offset of the soldering strip 102 or the falling off of the soldering strip 102, thereby increasing the reliability of connecting the battery cells in series into a battery string.

[0044] In some embodiments, the glue dot structure 101 is a conductive glue, and the morphology of the edge glue dot structure 121 can be: along the first direction X, the two sides are small and the middle is large, similar to an olive shape. For the soldering strip 102, the soldering strip 102 is usually connected to the middle part of the conductive glue. Therefore, setting the edge glue dot structure 121 to be olive-shaped can increase the contact area between the edge glue dot structure 121 and the soldering strip 102, thereby increasing the connection reliability between the edge glue dot structure 121 and the soldering strip 102 while reducing the contact resistance, thereby improving the performance of the battery cell.

[0045] In some embodiments, the glue point structure 101 is an insulating glue, and the shape of the edge glue point structure 121 can be: along the first direction X, the two sides are large and the middle is small, similar to an hourglass shape. For the welding strip 102, in the edge area 110, the welding strip 102 is prone to displacement. In order to avoid electrical connection between the welding strip 102 and other structures that should not be electrically connected after displacement, the edge glue point structure 121 is set to an hourglass shape, so that even if the welding strip 102 is displaced, it is still isolated by the insulating glue, thereby further improving the reliability of the battery cell.

[0046] In some embodiments, along the second direction Y, the width of the glue point structure 101 located in the edge area 110 on the side away from the central area 120 is greater than the width on the side close to the central area 120. The closer to the edge area 110, the higher the possibility of connection failure between the glue point structure 101 and the solder strip 102. Therefore, the width of the glue point structure 101 located in the edge area 110 on the side away from the central area 120 is set to be greater than the width on the side close to the central area 120, thereby increasing the possibility of connection between the glue point structure 101 and the solder strip 102. Moreover, for the process of forming the glue point structure 101, it is necessary to form the width of the glue point structure 101 located in the edge area 110 on the side away from the central area 120 to be greater than the width on the side close to the central area 120. Then, the corresponding process of printing glue will increase the amount of glue on the side away from the central area 120. At this time, even if glue is missed, the projection area of ​​the glue point structure 101 on the surface of the substrate 100 will still increase, thereby increasing the reliability of the connection between the glue point structure 101 and the solder strip 102.

[0047] In some embodiments, the edge glue point structure 121 is a plurality of rows, and the area of ​​the positive projection of all the glue points 111 in the edge glue point structure 121 on the surface of the substrate 100 tends to increase in the direction from the edge area 110 to the center area 120. In other words, the closer the glue point 111 is to the edge area 110, the smaller the area of ​​the positive projection on the surface of the substrate 100. On the one hand, the process difficulty can be reduced. For the edge area 110 of the battery cell, the closer it is to the edge of the battery cell, the more difficult it is to print the glue point structure 101. The process difficulty can be reduced by reducing the area of ​​the glue point 111 near the edge part. On the other hand, under the premise that the total area of ​​the positive projection of any edge glue point structure 121 on the surface of the substrate 100 is greater than the total area of ​​the true projection of any center glue point structure 131 on the surface of the substrate 100, controlling the area of ​​the positive projection of the glue point 111 in the edge glue point structure 121 on the surface of the substrate 100 to increase can further increase the reliability of the connection between the edge area 110 welding strip 102 and the battery cell, thereby improving the reliability of the subsequent battery cells connected in series to form a battery string.

[0048] It should be noted that the increasing trend here can refer to the direction from the edge area 110 to the center area 120. The closer the glue dots 111 are to the edge area 110, the larger the area of ​​their direct projection on the surface of the substrate 100. It can also be an overall increasing trend, in which the area of ​​the direct projection of some glue dots 111 on the surface of the substrate 100 remains unchanged or slightly decreases. As long as the overall trend is increasing, it can be regarded as an increasing trend.

[0049] In some embodiments, the number of glue dots 111 in the edge glue dot structure 121 is greater than the number of glue dots 111 in the center glue dot structure 131. By setting the number of glue dots 111 in the edge glue dot structure 121 to be larger, the total area of ​​the positive projection of all glue dots 111 in the edge glue dot structure 121 on the surface of the substrate 100 can also be increased. Moreover, under the premise that the length of the glue dots 111 in the edge glue dot structure 121 is not less than the length of the glue dots 111 in the center glue dot structure 131, and / or the width of the glue dots 111 in the edge glue dot structure 121 is not less than the width of the glue dots 111 in the center glue dot structure 131, the added glue dots 111 also have a certain contact area with the solder strip 102, so that the reliability of the connection between the solder strip 102 and the battery cell is increased while ensuring that each glue dot 111 has a certain contact area with the solder strip 102 and the connection reliability.

[0050] In some embodiments, the edge glue point structures 121 are in multiple rows, the center glue point structures 131 are in multiple rows, and the spacing between adjacent edge glue point structures 121 is smaller than the spacing between adjacent center glue point structures 131. In other words, the arrangement of the glue point structures 101 in the edge area 110 is denser, and by controlling the arrangement of the glue point structures 101 in the edge area 110 to be denser, the tightness of the connection between the welding strip 102 in the edge area 110 and the substrate 100 can be improved, thereby further improving the reliability of the battery cell.

[0051] In some embodiments, under the premise that the length of the glue dot 111 in the edge glue dot structure 121 is greater than or equal to the length of the glue dot 111 in the central glue dot structure 131, and / or, in the second direction Y, the width of the glue dot 111 in the edge glue dot structure 121 is greater than or equal to the width of the glue dot 111 in the central glue dot structure 131, the spacing between adjacent edge glue dot structures 121 is smaller than the spacing between adjacent central glue dot structures 131, which will further increase the proportion of the coverage area of ​​the glue dot structure 101 on the surface of the substrate 100 in the edge region 110, thereby increasing the contact area of ​​the intersection structure between the welding strip 102 and the edge region 110, thereby improving the reliability of the battery cell.

[0052] In some embodiments, the substrate 100 includes a first side 130 and a second side 140 arranged along the second direction Y. In the same row of glue point structures 101, the length of the glue point 111 close to the second side 140 is greater than the length of the glue point 111 close to the first side 130. Close to the second side 140 is actually close to the edge of the battery cell and the adjacent battery cell in series. In the process of connecting the battery cells in series into a battery string, it is inevitable that the welding ribbon 102 will bend and change, and the welding ribbon 102 will move in the first direction X during the bending process. Therefore, the length of the glue point 111 close to the second side 140 is set to be greater than the length of the glue point 111 close to the first side 130, so that even if the welding ribbon 102 is offset in the first direction X, the welding ribbon 102 will still be in contact with the glue point 111, thereby increasing the reliability of the battery cells in the subsequent welding into a string.

[0053] In some embodiments, the substrate 100 includes a relative front side and back side. In the same row of glue dot structures 101 located on the front side, the length of the glue dot 111 close to the second side 140 is greater than the length of the glue dot 111 close to the first side 130. In the same row of glue dot structures 101 located on the back side, the length of the glue dot 111 close to the first side 130 is greater than the length of the glue dot 111 close to the second side 140. It can be understood that for the front side of the substrate 100, the side of the front side close to the second side 140 is the connection side for connecting in series with the adjacent battery cells, but for the back side of the substrate 100, the side of the back side close to the first side 130 is the connection side for connecting in series with the adjacent battery cells. Therefore, setting the length of the glue dot 111 close to the second side 140 on the front side to be larger and the length of the glue dot 111 close to the first side 130 on the back side to be larger can adapt to different connection conditions on the front and back sides.

[0054] In some embodiments, the width of the glue points 111 close to the first side 130 and the second side 140 may be greater than the width between the first side 130 and the second side 140. For the glue points 111 close to the first side 130 and the second side 140, these glue points 111 also belong to the glue points 111 at the edge of the battery cell. Therefore, setting the width of the glue points 111 close to the first side 130 and the second side 140 to be larger can also increase the reliability of the battery cell.

[0055] In some embodiments, the substrate 100 includes a first side 130 and a second side 140 arranged along the second direction Y, and the arrangement density of the glue points 111 near the second side 140 is greater than the arrangement density of the glue points 111 near the first side 130. Similarly, for the glue point structure 101 near the second side 140, these glue points 111 are close to the edge of the battery cell and the adjacent battery cell in series. In the process of connecting the battery cells in series into a battery string, the welding strip 102 will be bent or displaced by force. Therefore, by increasing the arrangement density of the glue points 111, the tightness of the connection between the glue points 111 and the welding strip 102 is improved, the stress resistance between the glue points 111 and the welding strip 102 is improved, and the disconnection between the welding strip 102 and the glue points 111 is reduced, thereby improving the reliability of the battery cell.

[0056] In some embodiments, the substrate 100 includes a first side 130 and a second side 140 arranged along the second direction Y, and some of the glue dots 111 located in the center area 120 close to the first side 130 are aligned along the first direction X, and some of the glue dots 111 located in the center area 120 close to the second side 140 are aligned along the first direction X, and the remaining glue dots 111 located in the same column along the first direction X and located in the center area 120 are mutually offset. In other words, the glue dots 111 located in the middle part of the center area 120 and in the same column are mutually offset along the first direction X, so that all the glue dots 111 will not be printed in the wrong position at the same time. For example, the center area 120 includes 5 rows of center glue dot structures, and these 5 rows of center glue dot structures are named as the first row center glue dot structure, the second row center glue dot structure to the fifth row center glue dot structure, wherein the printing position of the first row center glue dot structure is deviated, and the position of the second row center glue dot structure that is offset therefrom will not be printed deviated, so that the printing accuracy of the glue dots 111 can be improved.

[0057] In some embodiments, in the first direction X, the length of the glue dots 111 in the edge glue dot structure 121 is 1.3 mm to 2 mm, for example, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or 1.9 mm, etc., and the length of the glue dots 111 in the center glue dot structure 131 is 0.8 mm to 1.8 mm, for example, 1 mm, 1.1 mm, 1.3 mm, 1.6 mm or 1.7 mm, etc. For the edge glue point structure 121, the longer the length of the edge glue point structure 121 is, the higher the reliability of the connection between the battery cell and the solder strip 102 can be. The longer the length of the edge glue point structure 121 will lead to a reduction in the spacing between the edge glue point structures 121 of adjacent rows. If the edge glue point structure 121 is a conductive structure, the reduction in spacing may cause the edge glue point structures 121 of adjacent rows to short-circuit. Therefore, setting the length of the glue point 111 in the edge glue point structure 121 to 1.3mm~2mm can improve the reliability of the connection between the edge glue point structure 121 and the solder strip 102 while avoiding abnormalities in the battery cell; for the center glue point structure 131, the center glue point structure 131 does not need to improve the reliability of the connection too much. On the contrary, maintaining the spacing distance is more beneficial to the structure of the center area 120. Therefore, setting the length of the glue point 111 in the center glue point structure 131 to 0.8mm~1.8mm can be more adapted to the structure of the battery cell.

[0058] In some embodiments, in the first direction X, the difference between the length of the glue point 111 in the edge glue point structure 121 and the length of the glue point 111 in the central glue point structure 131 is 0.1 mm to 0.3 mm, for example, 0.15, 0.2 mm or 0.25 mm, etc. By controlling the difference between the length of the glue point 111 in the edge glue point structure 121 and the length of the glue point 111 in the central glue point structure 131, it is possible to avoid an excessive increase in the edge glue point structure 121, thereby improving the reliability of the battery cell forming a battery string while avoiding the waste of the glue point 111.

[0059] refer to Figure 2 , Figure 2 Another top view of a battery cell provided in accordance with an embodiment of the present disclosure.

[0060] In some embodiments, the extension direction of the glue point 111 in the edge glue point structure 121 may form an angle with the first direction X. In other words, the extension direction of the glue point 111 is an inclined direction. Thus, compared with the structure in which the extension direction of the glue point 111 in the edge glue point structure 121 is parallel to the first direction X, the glue point 111 whose extension direction is an inclined direction may be closer to the central area 120. For example, the distance between the glue point 111 whose extension direction is parallel to the first direction X and the edge of the battery cell is 5 mm everywhere. Then, the distance between the glue point 111 whose extension direction is an inclined direction and the edge of the battery cell is 5 mm at only one point, and the distance between the rest of the glue point 111 and the edge of the battery cell is less than 5 mm, so that the edge glue point structure 121 is as close to the central area 120 as possible. Thus, on the one hand, in the process of forming the glue point 111, the situation of missing printing of the edge glue point structure 121 can be reduced. On the other hand, the contact area between the glue point 111 and the soldering ribbon 102 will not be reduced.

[0061] It should be noted that the 5 mm mentioned above is only an example for ease of understanding, and does not limit the distance between the glue point and the edge of the battery cell to 5 mm. It can also be other distances and can be adjusted according to actual conditions.

[0062] In the embodiment of the present disclosure, for the edge area 110 of the battery cell, the edge area 110 is more likely to cause the welding tape 102 to fall off from the battery cell. Therefore, in the embodiment of the present disclosure, the total area of ​​all glue points 111 in each row of edge glue point structure 121 is set to be greater than the sum of the total areas of all glue points 111 in each row of central glue point structure 131, so that the contact area between the edge glue point structure 121 and the welding tape 102 can be increased, thereby improving the connection reliability between the welding tape 102 in the edge area 110 and the battery cell. In addition, the present disclosure also sets the length of the through hole 211 of the edge mesh structure 221 to be not less than the length of the through hole 211 in the central mesh structure 231, and / or the width of the edge mesh structure 221 is not less than the width of the through hole 211 in the central mesh structure 231, so that in the first direction X and / or the second direction Y, the contact length and / or contact width between the welding tape 102 and each glue point 111 will not be reduced, thereby avoiding affecting the connection reliability between the welding tape 102 and each glue point 111.

[0063] Another embodiment of the present disclosure further provides a photovoltaic module, which may include the battery cells in some or all of the above-mentioned embodiments. A photovoltaic module provided by an embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the parts that are the same or similar to the above-mentioned embodiments can refer to the above-mentioned embodiments and will not be repeated below.

[0064] refer to Figure 3 and Figure 4 , Figure 3 A schematic diagram of the structure of a photovoltaic module provided by an embodiment of the present disclosure is shown in FIG. Figure 4 For along Figure 3 Cross-section along the MM1 direction.

[0065] The photovoltaic module includes: a battery string, which is formed by connecting a plurality of battery cells 40 as described in all or part of the above embodiments; a packaging film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the packaging film 41 away from the battery string.

[0066] It is worth noting that the battery cells 40 are electrically connected to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel. The battery cells 40 may include sliced ​​battery cells, and the sliced ​​battery cells are formed by dividing the whole solar cell, so that the power loss of the photovoltaic module can be improved by the current drop of the sliced ​​battery cells, so as to improve the photoelectric conversion efficiency of the photovoltaic module.

[0067] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the battery cell, and the second encapsulation layer covers the other of the front side or the back side of the battery cell. Specifically, at least one of the first encapsulation layer or 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.

[0068] 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.

[0069] 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, 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.

[0070] Another embodiment of the present disclosure further provides a printing glue screen, which can be used to form the glue dot structure 101 in the above-mentioned battery cell embodiment. The following will describe a printing glue screen provided in the embodiment of the present disclosure in conjunction with the accompanying drawings. It should be noted that the parts that are the same or similar to the above-mentioned embodiments can refer to the above-mentioned embodiments and will not be repeated below.

[0071] refer to Figure 5 , Figure 5 A schematic structural diagram of an offset printing screen provided in one embodiment of the present disclosure.

[0072] In some embodiments, the offset printing screen may include: a main body 200 including two first areas 210 arranged along a first direction X and a second area 220 located between the first areas 210 .

[0073] The glue printing screen may further include: a plurality of rows of glue dispensing mesh structures 201 arranged along the first direction X, each row of glue dispensing mesh structures 201 including a plurality of through holes 211 arranged at intervals along the second direction Y, and the glue is printed on the surface of the solar cell through the through holes 211 .

[0074] Among them, the multi-row glue dispensing mesh structure 201 includes at least one row of edge mesh structures 221 located in each first area 210, and also includes at least one row of central mesh structures 231 located in the second area 220, the total area of ​​the orthographic projection of all through holes 211 in each row of edge mesh structures 221 on the surface of the main body 200 is greater than the total area of ​​the orthographic projection of all through holes 211 in each row of central mesh structures 231 on the surface of the main body 200, and in the first direction X, the length of the through hole 211 in the edge mesh structure 221 is greater than or equal to the length of the through hole 211 in the central mesh structure 231, and / or, in the second direction Y, the width of the through hole 211 in the edge mesh structure 221 is greater than or equal to the width of the through hole 211 in the central mesh structure 231.

[0075] By setting the total area of ​​the orthographic projection of all the through holes 211 in each row of the edge mesh structure 221 on the surface of the main body 200 to be larger than the total area of ​​the orthographic projection of all the through holes 211 in each row of the central mesh structure 231 on the surface of the main body 200, it is possible to ensure that even if the edge mesh structure 221 is missing, a glue dot structure with a certain surface area can still be formed on the surface of the solar cell, thereby ensuring the reliability of the glue dot structure formed on the surface of the solar cell by the printing glue screen. In addition, by setting the length of the through hole 211 in the edge mesh structure 221 to be greater than or equal to the length of the through hole 211 in the central mesh structure 231, and / or the width of the through hole 211 in the edge mesh structure 221 to be greater than or equal to the width of the through hole 211 in the central mesh structure 231, it is possible to ensure the contact area between the solder strip and the glue dot formed by the printing screen, thereby avoiding affecting the reliability of the connection between the solder strip and each glue dot.

[0076] In some embodiments, the main body 200 includes two opposite sides arranged along the second direction Y, wherein the arrangement density of the through holes 211 on one side is greater than the arrangement density of the through holes 211 on the other side. It can be understood that the two opposite sides of the main body 200 arranged along the second direction Y correspond to the surface of the solar cell, that is, the two sides of the solar cell used to connect with the adjacent cells, and in the process of connecting the cells in series into a cell string, the welding strip will be bent or displaced by force, therefore, setting the arrangement density of the through holes 211 on one side to be greater than the arrangement density of the through holes 211 on the other side can make the arrangement density of the glue point formed on the surface of the cell higher, thereby improving the connection reliability between the welding strip and the glue point on one side of the cell.

[0077] In some embodiments, the main body 200 includes two opposite sides arranged along the second direction Y, and some through holes 211 near the two sides are aligned along the first direction X, and the remaining through holes in the same column along the first direction X and located in the second area 220 are staggered. For example, there are 5 rows of central mesh structures 231, namely the first row of central mesh structures, the second row of central mesh structures to the fifth row of central mesh structures, wherein the first row of central mesh structures and the second row of central mesh structures are staggered with each other, then, when the glue point printing of the first row of central mesh structures deviates, the second row of central mesh structures can be used for printing, and similarly, when the glue point printed by the second row of central mesh structures deviates, the first row of central mesh structures can be used for printing, thereby improving the accuracy of the glue point printed by the printing screen.

[0078] In some embodiments, the structure of the through hole 211 may correspond to the structure of the glue point in the above-mentioned battery cell embodiment. For example, in the direction from the first area 210 to the second area 220, the area of ​​the through hole 211 in the edge mesh structure 221 projected on the surface of the main body 200 tends to increase, etc. The same or corresponding content can refer to the description of the glue point structure in the above-mentioned embodiment, which will not be repeated here.

[0079] In some embodiments, in the first direction X, the length of the through hole 211 in the edge mesh structure 221 is 1.3 mm to 2 mm, for example, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm or 1.9 mm, etc., and the length of the through hole 211 in the central mesh structure 231 is 0.8 mm to 1.8 mm, for example, 1 mm, 1.1 mm, 1.3 mm, 1.6 mm or 1.7 mm, etc. In this way, glue dots of corresponding sizes can be formed on the surface of the battery cell, thereby improving the connection reliability between the glue dots 111 at the edge of the battery cell and the soldering ribbon 102.

[0080] The difference between the length of the through hole 211 in the edge mesh structure 221 and the length of the through hole 211 in the central mesh structure 231 can be 0.1mm to 0.3mm, for example 0.15, 0.2mm or 0.25mm, etc., thereby avoiding waste of glue when printing glue dots 111 on the surface of the battery cell while ensuring increased reliability.

[0081] In some embodiments, the extension direction of the through hole 211 in the edge mesh structure 221 may also be at an angle to the first direction X, so that the extension direction of the glue point formed on the surface of the battery cell is at an angle to the first direction X. The same or corresponding description can refer to the description in the above-mentioned battery cell, which will not be repeated here.

[0082] 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 battery cell, characterized in that: include: A substrate, the substrate comprising two edge regions arranged along a first direction and a central region located between the edge regions; A plurality of rows of glue dot structures arranged along the first direction, each row of the glue dot structures comprising a plurality of glue dots arranged at intervals along the second direction, the glue dots in each row of the glue dot structures being used for fixed contact with the same welding strip; Among them, the multiple rows of glue dot structures include at least one row of edge glue dot structures located in each of the edge areas, and also include at least one row of central glue dot structures located in the central area, the total area of ​​the orthographic projections of all the glue dots in each row of the edge glue dot structures on the substrate surface is larger than the total area of ​​the orthographic projections of all the glue dots in each row of the central glue dot structures on the substrate surface, and in the first direction, the length of the glue dots in the edge glue dot structure is greater than or equal to the length of the glue dots in the central glue dot structure, and / or, in the second direction, the width of the glue dots in the edge glue dot structure is greater than or equal to the width of the glue dots in the central glue dot structure.

2. The battery cell according to claim 1, characterized in that: The edge glue dot structure is in multiple rows, and in the direction from the edge area to the center area, the areas of the positive projections of all the glue dots in the edge glue dot structure on the substrate surface tend to increase.

3. The battery cell according to claim 1, characterized in that: The number of the glue dots in the edge glue dot structure is greater than the number of the glue dots in the center glue dot structure.

4. The battery cell according to claim 1, characterized in that: The edge glue dot structures are in multiple rows, the center glue dot structures are in multiple rows, and the spacing between adjacent edge glue dot structures is smaller than the spacing between adjacent center glue dot structures.

5. The battery cell according to claim 1, characterized in that: The base includes a first side and a second side arranged along the second direction. In the same row of the glue dot structures, the length of the glue dot close to the second side is greater than the length of the glue dot close to the first side.

6. The battery cell according to claim 1 or 5, characterized in that: The base includes a first side and a second side arranged along the second direction, and an arrangement density of the glue dots close to the second side is greater than an arrangement density of the glue dots close to the first side.

7. The battery cell according to claim 1, characterized in that: Along the second direction, the width of the glue point structure located in the edge area at a side away from the central area is greater than the width at a side close to the central area.

8. The battery cell according to claim 1, characterized in that: The base includes a first side and a second side arranged along the second direction, part of the glue dots located in the center area close to the first side are aligned along the first direction, part of the glue dots located in the center area close to the second side are aligned along the first direction, and the remaining glue dots that are in the same column along the first direction and located in the center area are staggered with each other.

9. A photovoltaic module, characterized in that: include: A battery string, formed by connecting a plurality of battery cells as claimed in any one of claims 1 to 8; 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 facing away from the battery string.

10. A printing glue screen for dispensing glue on solar cells, characterized in that: include: A main body, the main body comprising two first areas arranged along a first direction and a second area located in the middle of the first areas; a plurality of rows of glue-dispensing mesh structures arranged along the first direction, each row of the glue-dispensing mesh structures comprising a plurality of through holes arranged at intervals along a second direction, and glue is printed on the surface of the solar cell sheet through the through holes; Among them, the multiple rows of glue-dotting mesh structures include at least one row of edge mesh structures located in each of the first areas, and also include at least one row of center mesh structures located in the second area, the total area of ​​the orthographic projection of all the through holes in each row of the edge mesh structures on the main body surface is larger than the total area of ​​the orthographic projection of all the through holes in each row of the center mesh structures on the main body surface, and in the first direction, the length of the through holes in the edge mesh structure is greater than or equal to the length of the through holes in the center mesh structure, and / or, in the second direction, the width of the through holes in the edge mesh structure is greater than or equal to the width of the through holes in the center mesh structure.

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