photovoltaic modules

Abstract

This application relates to the photovoltaic field and provides a photovoltaic module, including: a back contact cell, a first main busbar and a second main busbar located on the back contact cell, a first through-connecting line connecting the first main busbar and a second through-connecting line connecting the second main busbar; a first solder strip connected to the first main busbar and having a first overlap region with the second through-connecting line; a second solder strip connected to the second main busbar and having a second overlap region with the first through-connecting line; a first insulating layer and a second insulating layer, the first insulating layer being located in the first overlap region and extending for a certain distance, and the width of the first insulating layer decreasing; the second insulating layer being located in the second overlap region and extending for a certain distance, and the width of the second insulating layer decreasing. The photovoltaic module provided by this application can at least improve the welding pull between the solder strip and the main busbar, thereby improving the welding quality.

Description

Technical Field

[0001] This application relates to the photovoltaic field, and in particular to a photovoltaic module. Background Technology

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

[0003] The main factors affecting the photoelectric conversion efficiency and yield of solar cells include two aspects: optical loss, which includes shading loss, carrier recombination loss of the substrate, carrier recombination loss of highly doped films, and refractive loss of films; and electrical loss, which includes the resistance loss of the material itself, contact loss of the electrodes, contact loss between the solder ribbon and the solar cell, and problems such as poor soldering between the solder ribbon and the solar cell.

[0004] Therefore, there is an urgent need in the field to provide a solar cell and photovoltaic module that can reduce electrical and optical losses, thereby improving the photoelectric conversion efficiency of the corresponding solar cell and the yield of the photovoltaic module. Summary of the Invention

[0005] This application provides a photovoltaic module that at least helps to improve the yield of photovoltaic modules.

[0006] According to some embodiments of this application, this application provides a photovoltaic module, including: a battery string, the battery string including: a plurality of back-contact cells, each back-contact cell including: a first main grid line and a second main grid line alternately arranged along a first direction, the first main grid line including a first connection area and a first spacing area, the second main grid line including a second connection area and a second spacing area; a first through-connecting line and a second through-connecting line, the first through-connecting line passing through the second spacing area and connecting to at least two of the first connection areas, the second through-connecting line passing through the first spacing area and connecting to at least two of the second connection areas; wherein, the plurality of back-contact cells include at least a first back-contact cell, a second back-contact cell, and a third back-contact cell arranged sequentially adjacent to each other; a first solder strip extending along a second direction, the first solder strip being used to electrically connect the first main grid line of the second back-contact cell and the second main grid line of the first back-contact cell; wherein, the first solder strip passes through... A first insulating layer is disposed in the first interval region and electrically connected to the first connection region; a first overlapping region exists between the first solder strip and the second through-connector; a second solder strip extends along a second direction, the second solder strip being used to electrically connect the second main busbar of the second back contact cell and the first main busbar of the third back contact cell; wherein the second solder strip passes through the second interval region and is electrically connected to the second connection region; a second overlapping region exists between the second solder strip and the first through-connector; a first insulating layer is located in the first overlapping region and extends a certain distance along the first direction; the width of the first insulating layer decreases along the second direction from the middle of the first insulating layer to the end of the first insulating layer; a second insulating layer is located in the second overlapping region and extends a certain distance along the first direction; the width of the second insulating layer decreases along the second direction from the middle of the second insulating layer to the end of the second insulating layer.

[0007] In some embodiments, the first through-connecting line and the second through-connecting line are disposed adjacent to each other; the first insulating layer is also located at the intersection of the first connection area and the first through-connecting line, and / or the second insulating layer is also located at the intersection of the second connection area and the second through-connecting line.

[0008] In some embodiments, the thickness of the first insulating layer decreases along the direction from the middle of the first insulating layer to the end of the first insulating layer; and / or, the thickness of the second insulating layer decreases along the direction from the middle of the second insulating layer to the end of the second insulating layer.

[0009] In some embodiments, the top surface of the first insulating layer away from the first through-connector is not higher than the top surface of the first connection area.

[0010] In some embodiments, the first insulating layer includes a stacked first film layer and a deformation film layer, the deformation film layer being used to reduce the stress during the curing of the first insulating layer; and / or, the deformation film layer being used to reduce the thermal stress of the back contact cell during the welding process.

[0011] In some embodiments, the top surface of the deformable film layer is an arc-shaped curved surface.

[0012] In some embodiments, the radian of the arcuate surface is 0.5 rad to 1.1 rad.

[0013] In some embodiments, the width of the first insulating layer along the first direction ranges from 0.15 mm to 0.8 mm.

[0014] In some embodiments, the back contact cell further includes: a battery substrate; a first sub-grid line and a second sub-grid line arranged alternately along a second direction, wherein the first main grid line is electrically connected to the first sub-grid line, and the second main grid line is electrically connected to the second sub-grid line.

[0015] In some embodiments, the end of the first sub-gate line and the second main gate line have a first insulation distance along the first direction; the end of the second sub-gate line and the first main gate line have a second insulation distance along the first direction.

[0016] In some embodiments, the battery string further includes a third insulating layer located at the ends of the first sub-grid lines and the ends of the second sub-grid lines.

[0017] The technical solution provided in this application has at least the following advantages:

[0018] In the technical solution provided in this application embodiment, the back contact cell includes a first through-connecting line and a second through-connecting line. The first through-connecting line passes through the second interval area and connects to at least two first connecting areas. The second through-connecting line passes through the first interval area and connects to at least two second connecting areas, thereby enabling interconnection between positive and negative main grids of the same polarity. This ensures more uniform electrical performance among main grids of the same polarity. The back contact cell becomes a unified whole with uniform electrical performance, thereby improving the blackening phenomenon of EL strips and blocks in IBC cells during EL testing of the battery module, effectively avoiding IBC battery module mismatch, and improving the power of the module.

[0019] Secondly, a first insulating layer and a second insulating layer are configured. The first insulating layer is located in the first overlapping area of ​​the first solder strip and the second through-connector line, and the second insulating layer is located in the second overlapping area of ​​the second solder strip and the first through-connector line. Along the axis of the first connecting area pointing towards the end of the first insulating layer, the width of the first insulating layer decreases in the second direction; similarly, along the axis of the second connecting area pointing towards the end of the second insulating layer, the width of the second insulating layer decreases in the second direction. This approach effectively eliminates the risk of incomplete coverage of the through-connector line due to deviations between the printed through-connector line and the insulating stencil constituting the first and second insulating layers. Secondly, widening the width of the insulating layers in the first and second overlapping areas increases the area between the insulating stencil and the solder strip, thereby distributing the pressure during solder strip lamination to the contact surface between the first insulating layer and the solar cell, thus reducing the force and lowering the risk of solar cell breakage. Thirdly, it ensures sufficient insulation and reduces the height of the insulating stencil, thereby guaranteeing the welding pull between the solder strip and the main grid and improving welding quality. Attached Figure Description

[0020] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the drawings in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this application or in the conventional art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a photovoltaic module provided in one embodiment of this application;

[0022] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0023] Figure 3 for Figure 2 A sectional view along section A1-A2;

[0024] Figure 4 for Figure 2 A sectional view along section B1-B2;

[0025] Figure 5 for Figure 2 A sectional view along section C1-C2;

[0026] Figure 6This application provides a schematic diagram of the structure of a back contact cell in a photovoltaic module according to an embodiment of the present application;

[0027] Figure 7 A cross-sectional view of a first insulating layer in a photovoltaic module provided in an embodiment of this application;

[0028] Figure 8 Another cross-sectional view of a first insulating layer in a photovoltaic module provided in an embodiment of this application;

[0029] Figure 9 This is a schematic diagram of another structure of a photovoltaic module provided in an embodiment of this application. Detailed Implementation

[0030] As can be seen from the background technology, the yield rate of current photovoltaic modules is not good.

[0031] This application provides a photovoltaic module in which the width of the first insulating layer on the first through-connecting line decreases, and the width of the second insulating layer on the second through-connecting line decreases, so as to increase the welding pull between the solder strip and the main grid line, thereby improving the yield of the photovoltaic module.

[0032] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0033] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. In addition, the character " / " in this document generally indicates that the related objects before and after it have an "or" relationship.

[0035] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0036] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0037] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0038] In the accompanying drawings corresponding to the embodiments of this application, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0039] In the description of the embodiments of this application, when a component "includes" another component, other components are not excluded unless otherwise stated, and other components may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or it can have another component present in between. Moreover, 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 indicates that no other components are located in between.

[0040] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description of the various embodiments and the appended claims, the term "part" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0041] The embodiments of this application will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in this application can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0042] Figure 1 This is a schematic diagram of a photovoltaic module provided in one embodiment of this application; Figure 2 for Figure 1 A magnified view of a section at point A in the middle; Figure 3 for Figure 2 A sectional view along section A1-A2; Figure 4 for Figure 2 A sectional view along section B1-B2; Figure 5 for Figure 2 A sectional view along section C1-C2.

[0043] refer to Figures 1-5According to some embodiments of this application, this application provides a photovoltaic module, including: a battery string, the battery string including: a plurality of back-contact cells, the back-contact cells including: a first main busbar 110 and a second main busbar 120 alternately arranged along a first direction X, the first main busbar 110 including a first connection area 111 and a first spacing area 112, the second main busbar 120 including a second connection area 121 and a second spacing area 122; a first through-connecting line 131 and a second through-connecting line 132, the first through-connecting line 131 passing through the second spacing area 122. Region 122 is connected to at least two first connection regions 111, and a second through connection line 132 passes through the first interval region 112 and is connected to at least two second connection regions 121; wherein, the plurality of back contact cells include at least a first back contact cell, a second back contact cell, and a third back contact cell arranged sequentially adjacent to each other; a first solder strip 151 extends along the second direction Y, and the first solder strip 151 is used to electrically connect the first main grid line 110 of the second back contact cell and the second main grid line 120 of the first back contact cell; wherein, the first solder strip 151 passes through A first solder strip 151 is disposed in the first interval region 112 and electrically connected to the first connection region 111; a first overlap region 105 exists between the first solder strip 151 and the second through-connecting line 132; a second solder strip 152 extends along the second direction and is used to electrically connect the second main grid line 120 of the second back contact cell and the first main grid line 110 of the third back contact cell; wherein, the second solder strip 152 passes through the second interval region 122 and is electrically connected to the second connection region 121; a second overlap region 105 exists between the second solder strip 152 and the first through-connecting line 131. 6; First insulating layer 141, the first insulating layer 141 is located in the first overlapping region 105 and extends a certain distance along the first direction X; along the direction from the middle of the first insulating layer 141 to the end of the first insulating layer 141, the width of the first insulating layer 141 decreases along the second direction Y; Second insulating layer 142, the second insulating layer 142 is located in the second overlapping region 106 and extends a certain distance along the first direction X; along the direction from the middle of the second insulating layer 142 to the end of the second insulating layer 142, the width of the second insulating layer 142 decreases along the second direction Y.

[0044] In the technical solution provided in this application embodiment, the back contact solar cell includes a first through-connecting line 131 and a second through-connecting line 132. The first through-connecting line 131 passes through the second interval region 122 and connects to at least two first connecting regions 111. The second through-connecting line 132 passes through the first interval region 112 and connects to at least two second connecting regions 121, so that the positive and negative main grids of the same polarity are interconnected, thereby ensuring that the electrical performance between the main grids of the same polarity is more uniform. The solar cell becomes a whole with uniform electrical performance, thereby improving the blackening phenomenon of EL strips and blocks in IBC cells during EL testing of the battery module, effectively avoiding IBC battery module mismatch, and improving the power of the module.

[0045] Secondly, a first insulating layer 141 and a second insulating layer 142 are provided. The first insulating layer 141 is located in the first overlapping area 105 of the first solder strip 151 and the second through-connector 132, and the second insulating layer 142 is located in the second overlapping area 106 of the second solder strip 152 and the first through-connector 131. Along the axis of the first connection area 111 pointing towards the end of the first insulating layer 141, the width of the first insulating layer 141 decreases in the second direction. Similarly, along the axis of the second connection area 121 pointing towards the end of the second insulating layer 142, the width of the second insulating layer 142 decreases in the second direction. This effectively eliminates the risk that the insulating adhesive may not completely cover the through-connector due to deviations between the printed through-connector and the insulating adhesive screen forming the first insulating layer 141 and the second insulating layer 142. Secondly, widening the insulation layer width of the first overlapping region 105 and the second overlapping region 106 increases the area between the insulating adhesive and the solder strip constituting the first insulating layer 141 and the second insulating layer 142. This allows the pressure during the solder strip lamination process to be distributed to the contact surface between the first insulating layer and the solar cell, thereby reducing the force and lowering the risk of solar cell breakage. Thirdly, sufficient insulation is ensured, and the height of the insulating adhesive can be reduced, thus ensuring the welding pull between the solder strip and the main grid and improving welding quality.

[0046] The photovoltaic modules provided in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0047] Back-contact solar cells refer to solar cells where electrodes of different polarities (positive and negative electrodes) are located on the back of the substrate. An example is an IBC cell (Interdigitated Back Contact).

[0048] Figure 6 This is a schematic diagram of a back contact cell in a photovoltaic module, provided as an embodiment of this application.

[0049] refer to Figure 6The back contact solar cell includes a solar cell substrate 100, which includes a base having a first surface and a second surface disposed opposite to each other. The first surface has a textured structure, which allows only internal reflection of incident light to be introduced, thereby reducing optical loss and improving the photoelectric conversion efficiency of the cell. The first surface has a front surface field (FSF), in which the conductivity type of the doped ions is the same as that of the doped ions of the base. The field passivation effect reduces the minority carrier concentration on the surface, thereby reducing the surface recombination rate and also reducing the series resistance, thus improving the electron transport capability. The first surface also has a first passivation layer and a first antireflection layer, with the first passivation layer located on the surface of the front surface field and the first antireflection layer located on the surface of the first passivation layer. Note that the solar cell substrate 100 does not necessarily include the front surface field, the first passivation layer, and the first antireflection layer.

[0050] The back contact cell includes a first sub-grid line 101 and a second sub-grid line 102 arranged alternately along the second direction Y, a first main grid line 110 electrically connected to the first sub-grid line 101, and a second main grid line 120 electrically connected to the second sub-grid line 102.

[0051] The second surface of the substrate has alternating regions I and II, where region I is either region P or region N, and region II is either region P or region N. There is a gap between region P and region N. The first sub-gate line 101 is located in region I, and the second sub-gate line 102 is located in region II.

[0052] In some embodiments, there is no gap between the P region and the N region, and an insulating film layer is provided between the P region and the N region to achieve insulation between the P region and the N region, thereby achieving insulation between the first sub-gate line 101 and the second sub-gate line 102.

[0053] In some embodiments, the gap region is flush with the P-region and the N-region, i.e., the substrate is not etched. The P-region and the N-region are insulated from each other by some insulating film layer, which can be a passivation layer or an intrinsic semiconductor layer.

[0054] In some embodiments, the gap region is lower than the P region and the gap region is lower than the N region. The gap region has a trench that extends from the second surface toward the first surface. The trench is used to achieve automatic isolation between regions of different conductivity types, which can eliminate leakage caused by the formation of PN junctions between heavily doped P and N regions in the IBC battery, thus affecting battery efficiency.

[0055] In some embodiments, the surface of the gap can be a polished surface or a velvety surface.

[0056] In some embodiments, the P-region and N-region may each have a tunneling silicon oxide layer and a doped polycrystalline silicon layer, respectively, wherein the P-region has a P-type doped polycrystalline silicon layer and the N-region has an N-type doped polycrystalline silicon layer. In other embodiments, the P-region and N-region may each have an intrinsic amorphous silicon layer, a doped amorphous silicon layer, and a transparent conductive layer, respectively, wherein the P-region has a P-type doped amorphous silicon layer and the N-region has an N-type doped amorphous silicon layer.

[0057] In some embodiments, a second passivation layer and a second anti-reflection layer are disposed on the P region, the N region and the spacer region, and the first sub-gate line 101 and the second sub-gate line 102 are located on the second anti-reflection layer.

[0058] In some embodiments, the battery substrate 100 has a first edge 1, a second edge 2 disposed opposite to the first edge 1, and two third edges (not shown) for connecting the first edge 1 and the second edge 2. Chamfers are formed at the junctions of the first edge 1 and the third edges, and at the junctions of the second edge 1 and the third edges. The reason for forming the chamfers is that, in conventional solar cells, due to the limitations of the monocrystalline silicon refining process used to prepare the substrate, monocrystalline silicon rods can currently only be made into round shapes. After the silicon rod is produced, it is sliced, which means cutting the cross-section of the silicon rod into the shape of a monocrystalline silicon wafer (the area is calculated so that within a unit, the illumination area can be maximized, silicon rod material can be saved to the maximum extent, and it is also convenient for the production of battery cells and modules). Chamfers are often set at the junctions of the various boundaries of the substrate to reduce the external stress of the silicon wafer and avoid micro-damage to the edges of the silicon wafer.

[0059] In some embodiments, the back contact cell includes a first edge main grid 103 near the first edge 1 and a second edge main grid 104 near the second edge 2, wherein no welding portion is provided on the first edge main grid 103 and the second edge main grid 104, which can avoid the problem of damage to the edge of the cell due to the stress of the solder strip.

[0060] In some embodiments, the conductivity type of the first edge main gate 103 is different from that of the adjacent main gates, for example... Figure 6 The conductivity type of the first edge main gate 103 is different from that of the adjacent second main gate line 120.

[0061] In some embodiments, if the sum of the first edge main gate 103, the second edge main gate 104, the first main gate line 110, and the second main gate line 120 is an even number, then the reference... Figure 6 The conductivity type of the second edge main gate 104 corresponding to the second edge 12 of the substrate is the same as that of the second main gate line 120.

[0062] In other embodiments, if the sum of the first edge main gate, the second edge main gate, the first main gate line, and the second main gate line is an odd number, then the conductivity type of the second edge main gate corresponding to the second edge of the substrate is the same as the conductivity type of the first main gate line.

[0063] In some embodiments, the first edge main gate is electrically connected to a pad (not shown) located between the first edge main gate and the second main gate line via a connecting line. In other embodiments, the first edge main gate line is electrically connected to a first main gate line via a connecting line, such as a first through-connector 131. Similarly, the second edge main gate can be electrically connected to an adjacent second main gate line 120 via a second through-connector 132, thereby collecting charge carriers at the edge while avoiding edge breakage of the cell.

[0064] In some embodiments, the first through-connector 131 is electrically connected to all the first main grid lines 110 and the edge main grid lines of the same conductivity type, and the second through-connector 132 is electrically connected to all the second main grid lines 120 and the edge main grid lines of the same conductivity type. The first through-connector 131 connects the first main grid lines 110, and the second through-connector 132 connects the second main grid lines 120, enabling interconnection between positive and negative main grids of the same polarity. This ensures more uniform electrical performance among main grids of the same polarity. The solar cell becomes a unified whole with uniform electrical performance, thereby improving the blackening phenomenon of EL strips and blocks in IBC cells during EL testing, effectively avoiding IBC cell module mismatch, and improving module power.

[0065] In some embodiments, the material of the first through-connecting line 131 is the same as that of the first sub-gate line 101. The first through-connecting line 131 is made of burn-through paste. The first through-connecting line 131 also penetrates the passivation layer and is electrically connected to the corresponding collection film layer. In this way, the first through-connecting line 131 can not only realize the current flow of the first main gate line 110, but also collect the current on the substrate surface itself, thereby increasing the collection path and improving the efficiency of current collection.

[0066] In some embodiments, the paste of the first through-connector 131 is the same as that of the main grid line, i.e., the first through-connector 131 is composed of a non-burn-through paste. The first through-connector 131 is located on the surface of the passivation layer. This eliminates the need for specific arrangement of regions I and II on the substrate surface below the first through-connector 131 to prevent electrical contact and short circuits between the first through-connector 131 and the doped region of the other polarity. Furthermore, the first through-connector 131 does not damage the passivation layer, thus ensuring the integrity of the passivation layer and improving its passivation effect on the substrate. This helps reduce optical losses in the solar cell and improves its photoelectric conversion efficiency. In addition, since the non-burn-through paste does not contain excessive glass powder that could damage the PN junction, it effectively reduces metal recombination, increases the open-circuit voltage of the solar cell, and improves its conversion efficiency.

[0067] Traditional slurries consist of a mixture of metal powder, glass powder, and an organic carrier. Non-burn-through slurries contain less glass powder than traditional slurries, resulting in weak burn-through capability during sintering; they do not require or cannot burn through the passivation layer. Burn-through slurries, on the other hand, exhibit strong burn-through capability during sintering, enabling them to burn through the passivation layer.

[0068] In some embodiments, the first through-connecting line 131 can be a film layer or a conductive line with a conductive material, and it is only necessary to achieve electrical connection of the first main gate lines 110 with the same polarity.

[0069] It is worth noting that the second through connecting line 132 can also have the same design as the first through connecting line 131, which will not be repeated here.

[0070] In some embodiments, the first through-connector 131 and the second through-connector 132 are disposed adjacent to each other; the first insulating layer 141 is also located at the intersection of the first connection area 111 and the first through-connector 131, and / or, the second insulating layer 142 is also located at the intersection of the second connection area 121 and the second through-connector 132. In this way, the first through-connector 131 and the second through-connector 132 can be designed in the same position, requiring less arrangement of their positions and reducing the difficulty of the manufacturing process.

[0071] In some embodiments, the width of the first through-connecting line 131 is greater than the width of the first sub-grid line 101, and the width of the second through-connecting line 132 is greater than the width of the second sub-grid line 102. In this case, having a wider first through-connecting line 131 and a wider second through-connecting line 132 can improve the collection area and collection efficiency.

[0072] In some embodiments, the width of the first through-connecting line 131 along the second direction Y ranges from 10 μm to 55 μm. The width W1 of the first through-connecting line 131 along the second direction Y can be 10 μm to 16 μm, 16 μm to 22 μm, 22 μm to 30 μm, 30 μm to 38 μm, 38 μm to 46 μm, or 46 μm to 55 μm.

[0073] In some embodiments, the width of the second through connecting line 132 along the second direction Y ranges from 10μm to 55μm. The width W2 of the second through connecting line 132 along the first direction can be 10μm to 16μm, 16μm to 22μm, 22μm to 30μm, 30μm to 38μm, 38μm to 46μm, or 46μm to 55μm.

[0074] In some embodiments, the end of the first sub-gate line 101 and the second main gate line 120 have a first insulation distance along the first direction X; the end of the second sub-gate line 102 and the first main gate line 110 have a second insulation distance along the first direction X. The first insulation distance and the second insulation distance are used to ensure electrical insulation between the first sub-gate line 101 and the second main gate line 120 of the opposite conductivity type, and electrical insulation between the second sub-gate line 102 and the first main gate line 110 of the opposite conductivity type, respectively.

[0075] In some embodiments, the first insulating layer 141 is used to achieve electrical insulation between the second through-connector 132 and the first solder strip 151; the second insulating layer 142 is used to achieve electrical insulation between the first through-connector 131 and the second solder strip 152, thereby avoiding the problem of short circuits between gate lines of different conductivity types.

[0076] In some embodiments, the material of the first insulating layer 141 may be an insulating adhesive, such as EVA adhesive, acrylic adhesive, PET adhesive or PVA adhesive.

[0077] In some embodiments, the material of the second insulating layer 142 may be an insulating adhesive, such as EVA adhesive, acrylic adhesive, PET adhesive, or PVA adhesive.

[0078] The first insulating layer 141 is located in the first overlapping region 105 and extends a certain distance along the first direction; the width of the first insulating layer 141 decreases along the second direction from the middle to the end of the first insulating layer 141; the second insulating layer 142 is located in the second overlapping region 106 and extends a certain distance along the first direction; the width of the second insulating layer 142 decreases along the second direction from the middle to the end of the second insulating layer 142, and the width of the second insulating layer 142 decreases along the second direction from the axis of the second connecting region 121 to the end of the second insulating layer 142. This effectively eliminates the risk that the insulating adhesive cannot completely cover the through connecting line due to the deviation between the printed through connecting line and the insulating adhesive screen that constitutes the first insulating layer 141 and the second insulating layer 142. Secondly, widening the width of the insulating layers in the first overlapping region 105 and the second overlapping region 106 increases the area between the insulating adhesive and the solder strip constituting the first insulating layer 141 and the second insulating layer 142. This allows the pressure during the solder strip lamination process to be distributed to the contact surface between the first insulating layer and the solar cell, thereby reducing the force and lowering the risk of solar cell breakage. Thirdly, sufficient insulation is ensured, and the height of the insulating adhesive can be reduced, thus ensuring the welding pull between the solder strip and the main grid and improving welding quality.

[0079] In some embodiments, the width of the first insulating layer 141 along the second direction Y ranges from 0.15 mm to 0.8 mm. The widest width ranges from 0.2 mm to 0.8 mm, and the thinnest width ranges from 0.15 mm to 0.5 mm.

[0080] refer to Figure 2 The first insulating layer 141 or the second insulating layer 142 respectively includes a first part and a second part. The first part includes a second overlapping region 106, wherein the width of the first part along the first direction is greater than the width of the second part along the first direction.

[0081] by Figure 2 The first and second portions of the second insulating layer 142 shown are examples. The length L of the first portion along the first direction X ranges from 0.8 mm to 4 mm, and the spacing d between the first portion and the adjacent second sub-gate line 102 ranges from 0.1 mm to 5 mm.

[0082] In some embodiments, the thickness of the first insulating layer 141 decreases in the direction from the middle of the first insulating layer 141 to its end. This reduces the amount of the first insulating layer 141 used, thereby lowering costs and avoiding stress shrinkage caused by excessive adhesive curing, thus reducing the risk of cell warping.

[0083] In some embodiments, the thickness of the second insulating layer 142 decreases along the direction from the middle of the second insulating layer 142 to the end of the second insulating layer 142, in order to reduce manufacturing costs and the risk of cell warping.

[0084] In some embodiments, the top surface of the first insulating layer 141 away from the first through-connection line 131 is not higher than the top surface of the first connection area 111. Thus, the height of the first insulating layer 141 will not exceed the height of the first connection area 111, preventing the solder ribbon from being lifted by the first insulating layer 141 and thus reducing the contact area between the first connection area 111 near the first insulating layer 141 and the solder ribbon. This increases the welding area of ​​the solar cell and improves the yield of the photovoltaic module.

[0085] Figure 7 A cross-sectional view of a first insulating layer in a photovoltaic module provided in an embodiment of this application; Figure 8 Another cross-sectional view of the first insulating layer in a photovoltaic module provided in an embodiment of this application.

[0086] In some embodiments, reference Figure 7 The first insulating layer 141 includes a first film layer 1411 and a deformation film layer 1412 stacked together. The deformation film layer 1412 is used to reduce the stress during the curing of the first insulating layer 141; and / or, the deformation film layer 1412 is also used to reduce the thermal stress of the solar cell during the welding process. The materials of the first sub-busbar 101, the second sub-busbar 102, the first main busbar 110, and the second main busbar 120, namely aluminum-silicon alloy, have a linear thermal expansion coefficient (TCE) of 23 × 10⁻⁶. -6 K -1 This is much higher than the coefficient of thermal expansion of silicon wafers (3.5 × 10⁻⁶). -6 K -1 Therefore, during the sintering and cooling stage, the shrinkage of the aluminum-silicon alloy is greater than that of the silicon wafer, which ultimately leads to the convex warping of the solar cell. In this embodiment, the first insulating layer 141 is configured as a first film layer 1411 and a deformation film layer 1412. The deformation film layer 1412 reduces the thermal stress of the solar cell during the welding process, thereby reducing the degree of warping of the solar cell and improving the yield of the photovoltaic module.

[0087] In some embodiments, the top surface of the deformation film layer 1412 is an arc-shaped surface. Due to the arc-shaped surface, the thickness of the adhesive in the middle is larger, and the adhesive tends to shrink towards the middle when it is cured, which can improve the warping of the battery cell.

[0088] In some embodiments, the radian of the curved surface is 0.5 rad to 1.1 rad. The radian of the curved surface can be 0.5 rad, 0.6 rad, 0.7 rad, 0.8 rad, 0.9 rad, 1.0 rad, or 1.1 rad.

[0089] In some embodiments, reference Figure 8 The deformation film layer 1412 has multiple grooves 1413, which can relieve the stress during the curing of the first insulating layer 141 and improve the warping problem of the battery cell.

[0090] Figure 9 This is a schematic diagram of another structure of a photovoltaic module provided in an embodiment of this application.

[0091] In some embodiments, reference Figure 9 The battery string also includes a third insulating layer 143, which is located at the end of the first sub-grid line 101 and the end of the second sub-grid line 102 to ensure insulation between the first sub-grid line 101 and the second main grid line 120, and between the second sub-grid line 102 and the first main grid line 110.

[0092] In some embodiments, the photovoltaic module further includes: an encapsulating film covering the battery string; and a cover plate located on the side of the encapsulating film away from the battery string.

[0093] In some embodiments, the encapsulating film includes a first encapsulating film and a second encapsulating film. The first encapsulating film covers one of the front or back sides of the solar cell, and the second encapsulating film covers the other of the front or back sides of the solar cell. Specifically, at least one of the first or second encapsulating film can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene elastomer (POE) film, or polyethylene terephthalate (PET) film.

[0094] It is worth noting that the first encapsulating film and the second encapsulating film still have a dividing line before the lamination process. After the lamination process, the photovoltaic module will no longer have the concept of the first encapsulating film and the second encapsulating film. That is, the first encapsulating film and the second encapsulating film have formed an integral encapsulating film.

[0095] In some embodiments, the cover plate can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface, thereby increasing the utilization rate of incident light. The cover plate includes a first cover plate and a second cover plate, wherein the first cover plate is opposite to the first encapsulating film, and the second cover plate is opposite to the second encapsulating film; or the first cover plate is opposite to one side of the solar cell, and the second cover plate is opposite to the other side of the solar cell.

[0096] In the technical solution provided in this application embodiment, the back contact solar cell includes a first through-connecting line 131 and a second through-connecting line 132. The first through-connecting line 131 passes through the second interval region 122 and connects to at least two first connecting regions 111. The second through-connecting line 132 passes through the first interval region 112 and connects to at least two second connecting regions 121, so that the positive and negative main grids of the same polarity are interconnected, thereby ensuring that the electrical performance between the main grids of the same polarity is more uniform. The solar cell becomes a whole with uniform electrical performance, thereby improving the blackening phenomenon of EL strips and blocks in IBC cells during EL testing of the battery module, effectively avoiding IBC battery module mismatch, and improving the power of the module.

[0097] Secondly, a first insulating layer 141 and a second insulating layer 142 are provided. The first insulating layer 141 is located in the first overlapping area 105 of the first solder strip 151 and the second through-connector 132, and the second insulating layer 142 is located in the second overlapping area 106 of the second solder strip 152 and the first through-connector 131. Along the axis of the first connection area 111 pointing towards the end of the first insulating layer 141, the width of the first insulating layer 141 decreases in the second direction. Similarly, along the axis of the second connection area 121 pointing towards the end of the second insulating layer 142, the width of the second insulating layer 142 decreases in the second direction. This effectively eliminates the risk that the insulating adhesive may not completely cover the through-connector due to deviations between the printed through-connector and the insulating adhesive screen forming the first insulating layer 141 and the second insulating layer 142. Secondly, increasing the thickness of the insulating layers in the first overlapping region 105 and the second overlapping region 106 increases the area between the insulating adhesive constituting the first insulating layer 141 and the second insulating layer 142 and the solder strip. Furthermore, the insulating adhesive generally has a certain degree of adhesion, which can further fix the solder strip and prevent it from shifting. Thirdly, sufficient insulation can be ensured, and the height of the insulating adhesive can be reduced, thereby ensuring the welding pull between the solder strip and the main grid and improving the welding quality.

[0098] Those skilled in the art will understand that the above embodiments are specific examples of implementing this application, and in practical applications, various changes in form and detail can be made without departing from the spirit and scope of this application. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this application; therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A photovoltaic module, characterized in that, include: A battery string, comprising: a plurality of back-contact battery cells, each back-contact battery cell comprising: a first main grid line and a second main grid line alternately arranged along a first direction, the first main grid line comprising a first connection area and a first interval area, the second main grid line comprising a second connection area and a second interval area; a first through-connecting line and a second through-connecting line, the first through-connecting line passing through the second interval area and connecting to at least two of the first connection areas, the second through-connecting line passing through the first interval area and connecting to at least two of the second connection areas; wherein the plurality of back-contact battery cells comprises at least a first back-contact battery cell, a second back-contact battery cell, and a third back-contact battery cell arranged sequentially adjacent to each other; A first solder strip extending along a second direction is used to electrically connect the first main busbar of the second back contact cell and the second main busbar of the first back contact cell; wherein the first solder strip passes through the first spacing region and is electrically connected to the first connection region; there is a first overlap region between the first solder strip and the second through connection line; A second solder strip extending along the second direction is used to electrically connect the second main busbar of the second back contact cell and the first main busbar of the third back contact cell; wherein the second solder strip passes through the second spacing region and is electrically connected to the second connection region; a second overlap region exists between the second solder strip and the first through connection line; A first insulating layer is located in the first overlapping region and extends a certain distance along the first direction; the width of the first insulating layer decreases along the second direction from the middle of the first insulating layer to the end of the first insulating layer. The second insulating layer is located in the second overlapping region and extends a certain distance along the first direction; the width of the second insulating layer decreases along the second direction from the middle of the second insulating layer to the end of the second insulating layer.

2. The photovoltaic module according to claim 1, characterized in that, The first through-connecting line and the second through-connecting line are disposed adjacent to each other; the first insulating layer is also located at the intersection of the first connecting area and the first through-connecting line, and / or the second insulating layer is also located at the intersection of the second connecting area and the second through-connecting line.

3. The photovoltaic module according to claim 1, characterized in that, The thickness of the first insulating layer decreases along the direction from the middle of the first insulating layer to the end of the first insulating layer; and / or, the thickness of the second insulating layer decreases along the direction from the middle of the second insulating layer to the end of the second insulating layer.

4. The photovoltaic module according to claim 1 or 3, characterized in that, The top surface of the first insulating layer away from the first through-connector is not higher than the top surface of the first connection area.

5. The photovoltaic module according to claim 1, characterized in that, The first insulating layer includes a stacked first film layer and a deformation film layer, wherein the deformation film layer is used to reduce the stress during the curing of the first insulating layer; and / or, the deformation film layer is also used to reduce the thermal stress of the back contact cell during the welding process.

6. The photovoltaic module according to claim 5, characterized in that, The top surface of the deformable membrane is an arc-shaped curved surface.

7. The photovoltaic module according to claim 6, characterized in that, The radian of the curved surface is 0.5 rad to 1.1 rad.

8. The photovoltaic module according to claim 1, characterized in that, The width of the first insulating layer along the first direction ranges from 0.15 mm to 0.8 mm.

9. The photovoltaic module according to claim 1, characterized in that, The back contact battery cell further includes: a battery substrate; a first sub-grid line and a second sub-grid line arranged alternately along the second direction, wherein the first main grid line is electrically connected to the first sub-grid line, and the second main grid line is electrically connected to the second sub-grid line; the end of the first sub-grid line and the second main grid line have a first insulation distance along the first direction; and the end of the second sub-grid line and the first main grid line have a second insulation distance along the first direction.

10. The photovoltaic module according to claim 9, characterized in that, The battery string further includes a third insulating layer located at the ends of the first sub-grid lines and the ends of the second sub-grid lines.

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