Photovoltaic module

Abstract

The present disclosure relates to the field of photovoltaics, and provides a photovoltaic module which can at least improve the connection reliability of the welding portion and the grid line, and improve the connection reliability of the welding portion and the solder strip. The photovoltaic module comprises a cell string, the cell string comprising a plurality of cell pieces arranged along a first direction and a solder strip electrically connecting adjacent cell pieces. The cell piece comprises a substrate, a grid line and a welding portion. The grid line is located on the substrate; the welding portion is located on the substrate and is used to electrically connect the solder strip and the grid line; the welding portion comprises a main body portion and a branch structure connected to each other, the main body portion extends along a second direction, the branch structure comprises a plurality of branches arranged at intervals along the second direction, both sides of the main body portion are provided with branches, the branches extend along a third direction, the third direction intersects the second direction, and the distance between two adjacent branches along the second direction is less than the width of the solder strip.

Description

Technical Field

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

[0002] As fossil fuels are gradually depleted, solar energy is 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 use of electrical energy.

[0003] Photovoltaic modules are crucial devices for converting solar energy into electrical energy. A photovoltaic module consists of a cell string, which comprises multiple solar cells and solder strips electrically connecting adjacent cells. Each solar cell has grid lines and solder joints, which electrically connect the grid lines to the solder strips. However, current designs of these solder joints have certain issues, leading to a need to improve the reliability of the connection between the solder joints and the solder strips. Summary of the Invention

[0004] This disclosure provides a photovoltaic module that at least improves the connection reliability between the welded part and the grid line, and improves the connection reliability between the welded part and the solder strip.

[0005] According to some embodiments of this disclosure, a photovoltaic module is provided. The photovoltaic module includes: a battery string, the battery string including a plurality of battery cells arranged along a first direction and solder strips electrically connecting adjacent battery cells. Each battery cell includes: a substrate; grid lines located on the substrate; and a welding portion located on the substrate and used to electrically connect the solder strips and the grid lines. The welding portion includes a main body and a branch structure connected to each other. The main body extends along a second direction, and the branch structure includes a plurality of branches arranged at intervals along the second direction. The branches are provided on both sides of the main body, and the branches extend along a third direction, which intersects the second direction. In the second direction, the distance between two adjacent branches is less than the width of the solder strips.

[0006] In some embodiments, at least a portion of the branches located on one side of the main body are collinear with at least a portion of the branches located on the other side of the main body.

[0007] In some embodiments, the branch located on one side of the main body and the branch located on the other side of the main body are both arranged collinearly.

[0008] In some embodiments, the plurality of branches include first branches located at both ends of the main body and second branches located between adjacent first branches; wherein, each end of the main body is connected to two collinearly arranged first branches, and the second branch located on one side of the main body is staggered with the second branch located on the other side of the main body.

[0009] In some embodiments, the plurality of branches include a first branch located at both ends of the main body and a second branch located between the two first branches, wherein the length of the second branch is greater than the length of the first branch in the direction of the third.

[0010] In some embodiments, the grid lines include first and second fine grids arranged alternately along the first direction, and in the second direction, there is a first spacing region between adjacent first fine grids and a second spacing region between adjacent second fine grids, and the second branch is located within the first spacing region and / or the second spacing region.

[0011] In some embodiments, along the third direction, the length of the first branch is 0.05mm to 0.1mm, and the length of the second branch is 0.1mm to 0.3mm.

[0012] In some embodiments, the plurality of branches include a first branch located at both ends of the main body and a second branch located between adjacent first branches, wherein the width of the second branch is greater than the width of the first branch along a fourth direction.

[0013] In some embodiments, along the fourth direction, the width of the first branch is 0.01 mm to 0.1 mm, and the width of the second branch is 0.1 mm to 0.15 mm.

[0014] In some embodiments, the width of the main body along the first direction is greater than or equal to the width of the branch along the fourth direction.

[0015] The technical solutions provided in this disclosure have at least the following advantages:

[0016] In the photovoltaic module technical solution provided in this disclosure, the welding part includes a main body and a branch structure. The main body extends along a second direction, and the branch structure includes multiple branches extending along a third direction, which intersects with the second direction. This allows the branch structure to still make electrical connection with the grid lines even if the main body is misprinted and cannot effectively contact them when the welding part is printed on the substrate, thereby improving the connection reliability between the welding part and the grid lines. Furthermore, in the second direction, the distance between two adjacent branches is less than the width of the solder strip, ensuring that the solder strip contacts at least one branch. This increases the contact area between the solder strip and the welding part, further improving the connection reliability between the solder strip and the welding part. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures 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 disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a conductive strip and a battery substrate in a related technology.

[0019] Figure 2 This is a schematic diagram of a welded component in related technologies;

[0020] Figure 3 This is a schematic diagram of the structure of the solder ribbon and the solar cell in a photovoltaic module provided in an embodiment of the present disclosure;

[0021] Figure 4 This is a schematic diagram of a welding part in a photovoltaic module provided in an embodiment of the present disclosure;

[0022] Figure 5 This is another structural schematic diagram of the welding part in the photovoltaic module provided in the embodiments of this disclosure;

[0023] Figure 6 This is another structural schematic diagram of the welding part in a photovoltaic module provided in an embodiment of the present disclosure;

[0024] Figure 7 This is another structural schematic diagram of the welding part in the photovoltaic module provided in the embodiments of this disclosure;

[0025] Figure 8 This is a schematic diagram of another structure of the solder ribbon and the solar cell in a photovoltaic module provided in this embodiment of the present disclosure;

[0026] Figure 9 This is a partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure.

[0027] Explanation of reference numerals in the attached figures:

[0028] 10. Battery substrate; 11. Conductive strip; 101. Substrate; 102. Electrode; 103. Welded part; 113. Main body; 123. Branch; 20. Battery cell; 21. Welding strip; 201. Substrate; 202. Grid line; 212. First grid; 222. Second grid; 203. Welded part; 213. Main body; 223. Branch; 233. First branch; 243. Second branch; 22. Encapsulating film; 23. Cover plate. Detailed Implementation

[0029] Figure 1 This is a schematic diagram of a conductive strip and a battery substrate in related technologies. Figure 2 This is a schematic diagram of a welded component in related technologies. Figure 1 Only a partial structure of the conductive strip is shown.

[0030] refer to Figure 1 and Figure 2 The photovoltaic module includes a cell string, which includes a plurality of cell substrates 10 arranged along a first direction X and conductive strips 11 electrically connecting adjacent cell substrates 10. Each cell substrate 10 includes a substrate 101, an electrode 102, and a solder joint 103. The electrode 102 is located on the substrate 101; the solder joint 103 is located on the substrate 101 and is used to electrically connect the conductive strip 11 to the electrode 102.

[0031] In related technologies, to ensure electrical connection between the weldment 103 and the electrode 102, the weldment 103 is typically configured as an H-shape. Specifically, the weldment 103 includes a main body 113 and two branches 123 respectively connected to both ends of the main body 113. The main body 113 extends along a second direction Y, and the branches 123 extend along a first direction X. Thus, during the printing of the weldment 103, even if the main body 113 is offset during printing, causing a gap between the main body 113 and the electrode 102, the branches 123 still have the opportunity to connect electrically with the electrode 102, thereby ensuring electrical connection between the weldment 103 and the electrode 102.

[0032] In addition, in order to ensure that the main body 113 is in contact with the conductive strip 11, the related technology usually makes the length of the main body 113 along the second direction Y greater than the width of the conductive strip 11 along the second direction Y. This makes the distance between the two branches 123 along the second direction Y larger, making it difficult to ensure that the conductive strip 11 is in contact with the branch 123. The contact area between the conductive strip 11 and the welded part 103 is small, resulting in low reliability of the connection between the conductive strip 11 and the welded part 103.

[0033] In summary, the connection reliability between the welded component 103 and the conductive strip 11 in the related technology is low.

[0034] In this embodiment, the welding portion includes a main body and branch structures. The main body extends along a second direction, and the branch structures include multiple branches extending along a third direction, which intersects with the second direction. This allows the branch structures to electrically connect with the gate lines even if the main body is misaligned during printing on the substrate, thus improving the connection reliability between the welding portion and the gate lines. Furthermore, in the second direction, the distance between two adjacent branches is less than the width of the solder strip, ensuring that the solder strip contacts at least one branch. This increases the contact area between the solder strip and the welding portion, further enhancing the connection reliability between the solder strip and the welding portion.

[0035] In the description of the embodiments of this disclosure, 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 or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0036] 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 disclosure. 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.

[0037] In the description of the embodiments of this disclosure, 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. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0038] In the description of embodiments of this disclosure, 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).

[0039] In the description of the embodiments of this disclosure, 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 disclosure 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 disclosure.

[0040] In the description of the embodiments of this disclosure, 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. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0041] In the description of the embodiments disclosed herein, an electrical connection between one component and another means that both components are made of conductive materials and are directly connected or connected via other conductive materials, so that current flows between the two components when the photovoltaic module is generating electricity. An electrical contact between one component and another means that the two components are not only in contact, but also, because both components are made of conductive materials, current flows between them when the photovoltaic module is generating electricity.

[0042] In the accompanying drawings corresponding to the embodiments of this disclosure, 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.

[0043] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and 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 another component may be present therein. Additionally, 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 therein.

[0044] The embodiments of this disclosure 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 disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0045] Figure 3 This is a schematic diagram of a structure of the solder ribbon and the solar cell in a photovoltaic module provided in an embodiment of this disclosure. Figure 4 This is a schematic diagram of a welding section in a photovoltaic module provided in an embodiment of this disclosure. Figure 3 To better showcase the structure of the welded section, the weld strip was rendered with a transparent lens; additionally... Figure 3 Only a partial structure of the solder strip is shown; the part of the solder strip extending out of the cell is actually electrically connected to another cell.

[0046] refer to Figure 3 and Figure 4 The photovoltaic module includes a cell string, which includes multiple cells 20 arranged along a first direction X and solder strips 21 electrically connecting adjacent cells 20. Each cell 20 includes a substrate 201, grid lines 202, and solder joints 203. The grid lines 202 are located on the substrate 201; the solder joints 203 are located on the substrate 201 and are used to electrically connect the solder strips 21 and the grid lines 202; the solder joints 203 include a connected main body 213 and branch structures. The main body 213 extends along a second direction Y, and the branch structures include multiple branches 223 spaced apart along the second direction Y. Branches 223 are provided on both sides of the main body 213. The branches 223 extend along a third direction P, which intersects the second direction Y. Along the second direction Y, the distance between two adjacent branches 223 is less than the width of the solder strips 21.

[0047] Photovoltaic modules are used to convert solar energy into electrical energy.

[0048] The solar cell 20 can be one or any combination of TOPCON (Tunnel Oxide Passivated Contact), HIT / HJT (Heterojunction Technology), PERC (Passivated Emitter Rear Cell), thin-film solar cells, and tandem solar cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem solar cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells. Figure 2 Using cell 20 as an example, we have a TOPCON battery.

[0049] The battery cell 20 can be a whole cell or a sliced ​​cell. A sliced ​​cell refers to a cell formed by cutting a complete cell. Sliced ​​cells can be two-piece sliced ​​cells, three-piece sliced ​​cells, or four-piece sliced ​​cells, etc.

[0050] The substrate 201 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 201 may be a semiconductor substrate.

[0051] In some embodiments, the material of the substrate 201 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0052] In some embodiments, the substrate 201 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

[0053] The substrate 201 can also be a sapphire substrate, a silicon substrate on an insulator, or a germanium substrate on an insulator.

[0054] The substrate 201 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type dopant element, which can be at least one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0055] The substrate 201 has a first side (not identified) and a second side (not identified) opposite each other. In some embodiments, the battery cell 20 is a single-sided battery, in which case the first side can serve as a light-receiving surface for receiving incident light, and the second side serves as a backlight surface. In some embodiments, the battery cell 20 is a double-sided battery, in which case both the first and second sides can serve as light-receiving surfaces and can both be used to receive incident light. It is understood that the backlight surface referred to in the embodiments of this disclosure can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a backlight surface.

[0056] In some embodiments, a texturing process can be performed on at least one of the first and second surfaces to form a textured surface on at least one of the first and second surfaces. This can enhance the absorption and utilization rate of incident light on both the first and second surfaces of the substrate 201. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, pyramid textured surface not only reduces the reflectivity of the substrate 201 surface but also forms light traps, enhancing the absorption effect of the substrate 201 on incident light and improving the photoelectric conversion efficiency of the solar cell 20.

[0057] Specifically, if the solar cell 20 is a single-sided cell, a textured surface, such as a pyramidal textured surface, can be formed on the light-receiving surface of the substrate 201, while the back-lighting surface of the substrate 201 can be a polished surface, meaning the back-lighting surface of the substrate 201 is flatter than the light-receiving surface. It should be noted that for single-sided cells, a textured surface can also be formed on both the light-receiving and back-lighting surfaces of the substrate 201.

[0058] If the cell 20 is a bifacial cell, a textured surface can be formed on both the light-receiving surface and the back-lighting surface of the substrate 201.

[0059] The grid line 202 is used to collect the current generated by the cell 20 and transmit the current to the solder ribbon 21.

[0060] The solar cell can be a grid-connected cell, with the grid lines including main grids extending along a first direction and fine grids extending along a second direction. The welding portion further facilitates the electrical connection between the fine grids and the main grids. The solar cell 20 can also be a gridless cell, with the grid lines 202 being fine grids extending along the second direction. Figure 2 Taking cell 20 as an example, which is a gridless cell.

[0061] The first direction X can be perpendicular to the second direction Y.

[0062] The welding part 203 is used to electrically connect the grid wire 202 and the welding strip 21.

[0063] The material of the weld 203 can be conductive materials such as copper, silver, nickel or aluminum.

[0064] In some embodiments, the material of the welding portion 203 can be the same as the material of the grid line 202, and the welding portion 203 can be integrally formed with the grid line 202. In this way, the welding portion 203 can be formed simultaneously when the grid line 202 is fabricated. This is beneficial for improving the fabrication efficiency of the solar cell 20.

[0065] The welding section 203 includes a main body 213 and a branch structure. The extension direction of the main body 213 can be the same as the extension direction of the grid line 202, for electrical connection with the grid line 202 and the welding strip 21. The extension direction of the branch 223 in the branch structure intersects with the extension direction of the main body 213, so that the branch 223 can be electrically connected to the grid lines 202 on both sides of the main body 213, which can increase the contact area between the welding section 203 and the grid line 202, thereby improving the connection reliability between the welding section 203 and the grid line 202.

[0066] The main body 213 has branches 223 on both sides along the first direction X. This allows the main body 213 to achieve electrical connection with the adjacent gate line 202 if the printing offset occurs in the first direction X when the soldering part 203 is printed. This also helps to improve the connection reliability between the soldering part 203 and the gate line 202.

[0067] The intersection of the third direction P and the second direction Y includes the following scenarios: the third direction P is perpendicular to the second direction Y; the angle formed by the third direction P and the second direction Y is obtuse; or the angle formed by the third direction P and the second direction Y is acute. In some examples, the angle between the third direction P and the second direction Y can be 10° to 90°, for example, it can be 10°, 20°, 45°, 55°, 70°, 82°, or 90°, etc. When the third direction P is perpendicular to the second direction Y, the third direction P is parallel to the first direction X.

[0068] Figure 5 This is another structural schematic diagram of the welding part in the photovoltaic module provided in the embodiments of this disclosure.

[0069] refer to Figure 3 to Figure 5In some embodiments, at least some branches 223 located on one side of the main body 213 are collinearly arranged with at least some branches 223 located on the other side of the main body 213. Collinear arrangement of two branches 223 means that the two branches 223 are located on the same straight line. With this arrangement, when the solder ribbon 21 contacts one branch 223, and that branch 223 has collinearly arranged branches 223 on the other side of the main body 213, the solder ribbon 21 will also contact the other collinearly arranged branch 223. This helps to increase the contact area between the solder ribbon 21 and the branches 223, thereby improving the connection reliability between the welding portion 203 and the solder ribbon 21.

[0070] refer to Figure 3 and Figure 4 In some embodiments, the branch 223 located on one side of the main body 213 and the branch 223 located on the other side of the main body 213 are both arranged collinearly. With this arrangement, the solder strip 21 comes into contact with at least two collinearly arranged branches 223, thereby improving the connection reliability between the welding part 203 and the solder strip 21.

[0071] refer to Figure 3 and Figure 5 In some embodiments, the plurality of branches 223 include first branches 233 located at both ends of the main body 213 and second branches 243 located between adjacent first branches 233; wherein, each end of the main body 213 is connected to two collinearly arranged first branches 233, and the second branches 243 located on one side of the main body 213 are staggered with the second branches 243 located on the other side of the main body 213. The first branches 233 are branches 223 connected to the ends of the main body 213. The second branches 243 are branches 223 located between the two first branches 233. The two collinear first branches 233 are provided at the ends of the main body 213 so that if the main body 213 is offset in the first direction X during the printing of the soldering part 203, the first branches 233 can help the main body 213 achieve electrical connection with the gate line 202. Under the premise that the distance between adjacent branches 223 in the second direction Y is less than the width of the weld strip 21, the second branches 243 are staggered on both sides of the main body 213, which helps to reduce the number of second branches 243 and thus save the manufacturing cost of the welded part 203.

[0072] Figure 6 This is another structural schematic diagram of the welding part in a photovoltaic module provided in an embodiment of the present disclosure.

[0073] refer to Figure 6In some embodiments, the branches 223 on one side of the main body 213 and the branches 223 on the other side of the main body 213 are staggered. While ensuring that the distance between adjacent branches 223 in the second direction Y is less than the width of the weld strip 21, staggering the branches 223 on both sides of the main body 213 helps reduce the number of branches 223, thereby saving the manufacturing cost of the welded portion 203.

[0074] Figure 7 This is another structural schematic diagram of the welding part in the photovoltaic module provided in the embodiments of this disclosure.

[0075] refer to Figure 3 and Figure 7 In some embodiments, the plurality of branches 223 include first branches 233 located at both ends of the main body 213 and second branches 243 located between the two first branches 233. Along a third direction P, the length L2 of the second branch 243 is greater than the length L1 of the first branch 233. The first branch 233 is a branch 223 connected to the end of the main body 213. The second branch 243 is a branch 223 connected to the middle portion between the two ends of the main body 213. When the solder strip 21 is welded to the welding part 203, the contact probability between the solder strip 21 and the middle portion between the two ends of the main body 213 is greater, i.e., the contact probability between the solder strip 21 and the second branch 243 is greater. Setting the length L2 of the second branch 243 to be greater than the length L1 of the first branch 233 is beneficial to increasing the contact area between the welding part 203 and the solder strip 21, thereby improving the connection reliability between the welding part 203 and the solder strip 21.

[0076] Figure 8 This is another structural schematic diagram of the solder ribbon and solar cells in a photovoltaic module provided in this embodiment of the present disclosure. To clearly illustrate the structure of the welding section 203, the solder ribbon 21 is shown in perspective. Figure 8 The diagram illustrates a partial structure of the solder strip 21. Figure 8 Taking cell 20 as an example, it is a back-contact cell without a main grid.

[0077] refer to Figure 3 , Figure 7 and Figure 8 In some embodiments, the grid line 202 includes a first fine grid 212 and a second fine grid 222 arranged alternately along a first direction X. In the second direction Y, there is a first interval between adjacent first fine grids 212 and a second interval between adjacent second fine grids 222. The second branch 243 is located within the first interval and / or the second interval.

[0078] The battery cell 20 can be a back-contact battery. One of the first fine grid 212 and the second fine grid 222 is used to collect holes, and the other is used to collect electrons. A first gap between adjacent first fine grids 212 is used to leave a blank area so that the solder ribbon 21 can be electrically connected to the second fine grid 222. A second gap between adjacent second fine grids 222 is used to leave a blank area so that the solder ribbon 21 can be electrically connected to the first fine grid 212.

[0079] By placing the longer second branch 243 in the first spacing region, a short circuit can be avoided when the welding part 203 makes electrical connection between the longer second branch 243 and the adjacent first fine gate 212. Similarly, placing the longer second branch 243 in the second spacing region also prevents a short circuit when the welding part 203 makes electrical connection between the longer second branch 243 and the adjacent second fine gate 222. Furthermore, keeping the length of the first branch 233 connected to the end of the main body 213 relatively short helps to prevent a short circuit when the first branch 233 makes contact with adjacent non-standard fine gates.

[0080] In some embodiments, the length L1 of the first branch 233 along the third direction P is 0.05 mm to 0.1 mm, for example, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm, 0.09 mm, or 0.1 mm. The shorter length L1 of the first branch 233 within the above range helps to prevent short circuits caused by the first branch 233 contacting the irregular fine grid in the back contact battery; it also helps to reduce the manufacturing cost of the first branch 233.

[0081] The length L2 of the second branch 243 is 0.1mm to 0.3mm, for example, 0.1mm, 0.15mm, 0.2mm, 0.25mm or 0.3mm. The length L2 of the second branch 243 is within the above range. A larger length L2 of the second branch 243 is beneficial to increase the contact area between the second branch 243 and the welding strip 21, thereby improving the connection reliability between the welding part 203 and the welding strip 21.

[0082] In some embodiments, the substrate 201 includes two first sides disposed opposite each other along a first direction X, and no welding portion 203 is provided on the substrate 201 near the first side. In this way, microcracks in the battery cell 20 can be avoided due to welding stress when the solder strip 21 is welded to the welding portion 203 near the first side.

[0083] refer to Figure 7 and Figure 8In some embodiments, the plurality of branches 223 include first branches 233 located at both ends of the main body 213 and second branches 243 located between adjacent first branches 233. Along the fourth direction Q, the width of the second branch 243 is greater than the width of the first branch 233. The first branch 233 is a branch 223 connected to the end of the main body 213. The second branch 243 is a branch 223 connected to the middle portion between the two ends of the main body 213. When the solder strip 21 is welded to the welding part 203, the contact probability between the solder strip 21 and the middle portion between the two ends of the main body 213 is greater, i.e., the contact probability between the solder strip 21 and the second branch 243 is greater. Setting the width of the second branch 243 to be greater than the width of the first branch 233 is beneficial for increasing the contact area between the welding part 203 and the solder strip 21, thereby improving the connection reliability between the welding part 203 and the solder strip 21.

[0084] The fourth direction Q is perpendicular to the third direction P.

[0085] In some embodiments, along the fourth direction Q, the width of the first branch 233 is 0.01mm to 0.1mm, for example, 0.01mm, 0.03mm, 0.05mm, 0.07mm, or 0.1mm. The width of the second branch 243 is 0.1mm to 0.15mm, for example, 0.1mm, 0.11mm, 0.12mm, 0.13mm, or 0.15mm. The width of the second branch 243 is within the above range; a larger width is preferable, thereby increasing the contact area between the welded part 203 and the welding strip 21, and thus improving the connection reliability between the welded part 203 and the welding strip 21.

[0086] In some embodiments, the width of the main body 213 along the first direction X is greater than or equal to the width of the branch 223 along the fourth direction Q. The main body 213 is always in contact with the welding strip 21. Setting the width of the main body 213 to be larger is beneficial to increasing the contact area between the main body 213 and the welding strip 21, thereby improving the connection reliability between the welding part 203 and the welding strip 21.

[0087] In some embodiments, the width of the main body 213 along the first direction X is 0.05mm to 0.15mm, for example 0.05mm, 0.08mm, 0.1mm, 0.13mm or 0.15mm; the width of the branch 223 along the fourth direction Q is 0.01mm to 0.15mm, for example 0.01mm, 0.03mm, 0.05mm, 0.08mm, 0.1mm, 0.13mm or 0.15mm.

[0088] In some embodiments, the length of the main body portion 213 along the second direction Y is 0.3mm to 0.6mm, for example, 0.3mm, 0.4mm, 0.5mm, or 0.6mm. The length of the main body portion 213 is within the above range, and its relatively large length allows the welding strip 21 to still contact the main body portion 213 even if there is a slight offset in the second direction Y, thereby improving the connection reliability between the welding portion 203 and the welding strip 21.

[0089] The solder strip 21 extends along the first direction X for electrically connecting adjacent battery cells.

[0090] Understandable, Figure 3 This illustration shows a solar cell 20 electrically connected to three solder strips 21. Figure 8 The illustration shows a solar cell 20 electrically connected to six solder strips 21. In practice, the number of solder strips electrically connected to the solar cell can also be other values, such as 1, 2, 4, or 5. This disclosure does not limit the number of solar cells electrically connected to solder strips.

[0091] In some embodiments, the width of the solder strip 21 along the second direction Y is 0.15mm to 0.25mm, for example 0.15mm, 0.18mm, 0.2mm, 0.23mm or 0.25mm.

[0092] Figure 9 This is a partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure. Figure 9 Using TOPCON batteries as an example.

[0093] refer to Figure 9 In some embodiments, the photovoltaic module further includes an encapsulating film 22 and a cover plate 23, wherein the encapsulating film 22 is used to cover the surface of the battery string; and the cover plate 23 is used to cover the surface of the encapsulating film 22 facing away from the battery string.

[0094] In some embodiments, the encapsulating film 22 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the first and second surfaces of the battery cell 20, and the second encapsulating layer covers the other of the first and second surfaces of the battery cell 20. Specifically, at least one of the first and second encapsulating layers 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. Alternatively, at least one of the first and second encapsulating layers can also be an EP film, an EPE film, or a PVP film. Here, EP film refers to a co-extruded film composed of stacked EVA and POE films; EPE film refers to a co-extruded film formed by sequentially stacking EVA, POE, and EVA films; and PVP film refers to a co-extruded film formed by stacking POE, EVA, and POE films. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0095] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After the photovoltaic module is formed by lamination, there is no longer a 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 22.

[0096] In some embodiments, the cover plate 23 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 23 facing the encapsulating film 22 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 23 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0097] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A photovoltaic module, characterized in that, include: A battery string, the battery string comprising a plurality of battery cells arranged along a first direction and solder strips electrically connecting adjacent battery cells, the battery cells comprising: Base; A grid line, the grid line being located on the substrate; A welding section is located on the substrate and is used to electrically connect the welding strip and the grid line; the welding section includes a main body and a branch structure connected to each other, the main body extends along a second direction, the branch structure includes a plurality of branches spaced apart along the second direction, the branches are provided on both sides of the main body, the branches extend along a third direction, the third direction intersects with the second direction, and along the second direction, the distance between two adjacent branches is less than the width of the welding strip.

2. The photovoltaic module according to claim 1, characterized in that, At least a portion of the branches located on one side of the main body are collinear with at least a portion of the branches located on the other side of the main body.

3. The photovoltaic module according to claim 2, characterized in that, The branch located on one side of the main body and the branch located on the other side of the main body are both arranged collinearly.

4. The photovoltaic module according to claim 2, characterized in that, The plurality of branches include first branches located at both ends of the main body and second branches located between adjacent first branches; wherein, each end of the main body is connected to two collinear first branches, and the second branch located on one side of the main body is staggered with the second branch located on the other side of the main body.

5. The photovoltaic module according to any one of claims 1 to 4, characterized in that, The plurality of branches include a first branch located at both ends of the main body and a second branch located between the two first branches, wherein the length of the second branch is greater than the length of the first branch in the direction of the third.

6. The photovoltaic module according to claim 5, characterized in that, The grid line includes a first fine grid and a second fine grid arranged alternately along the first direction. In the second direction, there is a first interval region between adjacent first fine grids and a second interval region between adjacent second fine grids. The second branch is located within the first interval region and / or the second interval region.

7. The photovoltaic module according to claim 5, characterized in that, Along the third direction, the length of the first branch is 0.05mm to 0.1mm, and the length of the second branch is 0.1mm to 0.3mm.

8. The photovoltaic module according to any one of claims 1 to 4, characterized in that, The plurality of branches include a first branch located at both ends of the main body and a second branch located between adjacent first branches. Along a fourth direction, the width of the second branch is greater than the width of the first branch, and the fourth direction is perpendicular to the third direction.

9. The photovoltaic module according to claim 8, characterized in that, Along the fourth direction, the width of the first branch is 0.01mm to 0.1mm, and the width of the second branch is 0.1mm to 0.15mm.

10. The photovoltaic module according to claim 1, characterized in that, The width of the main body along the first direction is greater than or equal to the width of the branch along the fourth direction, which is perpendicular to the third direction.

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