A bc solar cell string and bc photovoltaic module
By printing multiple sub-solder pastes on the pads of the BC solar cell string, the problem of cold solder joints caused by solder ribbon slippage was solved, the soldering quality and production yield were improved, and the amount of solder paste used was reduced, thus achieving cost control.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TONGWEI SOLAR ENERGY (CHENGDU) CO LID
- Filing Date
- 2025-06-03
- Publication Date
- 2026-06-02
Smart Images
Figure CN224319812U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of solar cell technology, and in particular to a BC solar cell string and a BC photovoltaic module. Background Technology
[0002] In the process of manufacturing BC (Back Contact) solar cell strings, solder ribbons are currently soldered onto the pads on the BC solar cell string. Typically, solder paste is printed on the pads in the BC solar cell string, dried, and then the solder ribbons are placed on the dried solder paste before being soldered onto the pads.
[0003] However, the solder paste on the pads is usually in an arc shape, that is, the surface of the solder paste is an arched arc. When the solder ribbon is placed on the solder paste, it is easy for the solder ribbon to slip off the solder paste, causing the solder ribbon to shift relative to the pad, which can easily lead to cold solder joints between the solder ribbon and the pad. Utility Model Content
[0004] This application discloses a BC solar cell string and a BC photovoltaic module, which can prevent the solder strip from slipping off the dried solder paste during soldering, effectively avoiding solder strip misalignment and causing cold solder joints, and improving the soldering quality of the solder strip.
[0005] To achieve the above objectives, in a first aspect, this application discloses a solder paste stencil, which is used to print solder paste on the pads of a BC solar cell string, the solder paste being used for soldering ribbons to the pads, the solder paste stencil comprising:
[0006] ontology;
[0007] Multiple mesh holes are arranged on the body, each mesh hole corresponds to one pad, and at least one partition is provided in the mesh hole. The mesh hole is divided into multiple sub-mesh holes by the at least one partition. The multiple sub-mesh holes are arranged along a first direction. When the solder strip is soldered to the pad, the first direction is the width direction of the solder strip.
[0008] In one possible implementation, the mesh includes two opposing aperture walls extending along a first direction, and a partition extending along a second direction connecting the two aperture walls, the second direction being the length direction of the solder strip when it is soldered to the pad.
[0009] In one possible implementation, the plurality of said sub-mesh holes are arranged at equal intervals along the first direction.
[0010] In one possible implementation, the sub-mesh can be any one of a rectangular structure, a parallelogram structure, a trapezoidal structure, or a circular structure.
[0011] In one possible implementation, the number of sub-mesh openings is 2 to 4, and the number of partitions is 1 to 3.
[0012] In one possible implementation, along the second direction, the width of the sub-mesh is greater than the width of the pad.
[0013] In one possible implementation, along the first direction, the length of the sub-mesh is greater than the length of the separator.
[0014] In one possible implementation, the ratio of the sum of the areas of the plurality of sub-mesh openings to the sum of the areas of the at least one partition in one mesh opening ranges from 1.5 to 3.5.
[0015] In one possible implementation, along the first direction, the size of the mesh is 600mm to 850mm, the size of the sub-mesh is 150mm to 250mm, and the size of the partition is 50mm to 150mm.
[0016] Secondly, this application also discloses a BC solar cell string, comprising:
[0017] Multiple BC solar cell bodies, wherein the BC solar cell bodies are provided with solder pads;
[0018] Solder paste, which is disposed on the pads and used for soldering ribbons to the pads, includes a plurality of sub-solder pastes arranged along a first direction, wherein the first direction is the width direction of the solder ribbons when the solder ribbons are soldered to the pads.
[0019] In one possible implementation, the solder paste includes two opposing sides extending along a first direction, with a gap between adjacent sub-solder pastes extending along a second direction, which is the length direction of the solder strip when it is soldered to the pad.
[0020] In one possible implementation, the plurality of said sub-solder pastes are arranged at equal intervals along the first direction.
[0021] In one possible implementation, along the first direction, the length of the sub-solder paste is greater than the interval between two adjacent sub-solder pastes.
[0022] In one possible implementation, the ratio of the sum of the areas of the plurality of sub-solder pastes projected onto the BC solar cell body to the sum of the areas of the intervals in the solder paste ranges from 1.5 to 3.5.
[0023] In one possible implementation, the sub-solder paste is any one of a rectangular structure, a parallelogram structure, a trapezoidal structure, or a circular structure.
[0024] In one possible implementation, the number of sub-solder pastes is 2 to 4.
[0025] In one possible implementation, the width of the sub-solder paste is greater than the width of the pad along a second direction, the second direction being the length direction of the solder strip when the solder strip is soldered onto the pad.
[0026] In one possible implementation, along the first direction, the solder paste has a size of 600 mm to 850 mm, and the sub-solder paste has a size of 150 mm to 250 mm.
[0027] Thirdly, this application also discloses a BC photovoltaic module, comprising: the BC solar cell string described in any one of the second aspects.
[0028] Compared with the prior art, the beneficial effects of this application are as follows:
[0029] In this application, solder paste is applied to the pads, and the solder paste includes multiple sub-solder pastes, allowing multiple sub-solder pastes to be printed on the pads. Each sub-solder paste has an arched surface after drying. The multiple sub-solder pastes are arranged along a first direction, and the solder ribbon is soldered to the pads through these sub-solder pastes. That is, after the solder ribbon is placed on the dried solder paste, along the width of the solder ribbon, it can abut against the multiple sub-solder pastes located on the pads, allowing multiple areas of the solder ribbon to abut against the solder paste. This provides multiple support points for the solder ribbon, effectively preventing the solder ribbon from slipping off the solder paste, thus avoiding cold solder joints caused by solder ribbon slippage, which is beneficial to improving the performance of BC solar cell strings and effectively reducing rework due to cold solder joints, thereby improving the production yield of BC solar cell strings. Furthermore, it effectively reduces the amount of solder paste used, thus effectively reducing costs. Attached Figure Description
[0030] To more clearly illustrate the technical solutions in the embodiments of this application, 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.
[0031] Figure 1 This is a schematic diagram of the structure of a traditional solder paste stencil.
[0032] Figure 2(a) is a schematic diagram of the structure of solder paste obtained by traditional solder paste stencil printing after drying, and (b) is a schematic diagram of the structure of solder ribbon placed on the dried solder paste;
[0033] Figure 3 This is a schematic diagram of the structure of a solder paste stencil provided in an embodiment of this application;
[0034] Figure 4 This is a schematic diagram of a mesh structure provided in an embodiment of this application;
[0035] Figure 5 This is a schematic diagram of the pattern of solder paste obtained by solder paste screen printing according to an embodiment of this application;
[0036] Figure 6 This is a schematic diagram of the structure of solder paste after drying, provided in an embodiment of this application;
[0037] Figure 7 This is a schematic diagram of a structure provided in this application embodiment, showing a solder ribbon placed on dried solder paste;
[0038] Figure 8 This is a schematic diagram of a structure when the pattern of solder paste obtained by solder paste stencil printing is offset, as provided in an embodiment of this application;
[0039] Figure 9 This is a schematic diagram of the structure of a dried solder paste that has shifted direction, provided in an embodiment of this application;
[0040] Figure 10 This is a schematic diagram of a structure in which solder ribbon is placed on dried solder paste that has shifted after drying, according to an embodiment of this application;
[0041] Figure 11 This is a schematic diagram of the structure of a BC solar cell string provided in an embodiment of this application;
[0042] Figure 12 This is a schematic diagram of the structure of the second type of mesh provided in the embodiments of this application;
[0043] Figure 13 This is a schematic diagram of the structure of the third type of mesh provided in the embodiments of this application;
[0044] Figure 14 This is a schematic diagram of the structure of the fourth type of mesh provided in the embodiments of this application;
[0045] Figure 15 This is a schematic diagram of the pattern of the solder paste obtained by the second type of printing provided in the embodiments of this application;
[0046] Figure 16This is a schematic diagram of the pattern of the solder paste obtained by the third type of printing provided in the embodiments of this application;
[0047] Figure 17 This is a schematic diagram of the pattern of the fourth type of solder paste obtained by printing according to the embodiments of this application.
[0048] Explanation of reference numerals in the attached figures:
[0049] 01-Mesh; 02-Solder paste; 03-Pad; 04-Solder ribbon;
[0050] 1-Body; 2-Mesh opening; 21-Sub-mesh opening; 22-Separator; 23-Opening wall;
[0051] 3-Solder paste; 31-Sub-solder paste; 32-Side; 33-Spacer; 4-Solder ribbon; 5-Pad; 6-BC solar cell body;
[0052] 10- Solder paste mesh version;
[0053] 20-BC solar cell string. Detailed Implementation
[0054] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0055] In this application, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; 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, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.
[0056] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.
[0057] Currently, laser soldering of BC solar cell strings typically involves printing solder paste onto the pads in the BC solar cell string, drying the solder paste, placing the solder ribbon on the dried solder paste, applying pressure to the solder ribbon using a tooling device to ensure close contact between the solder ribbon and the solder paste, and then soldering the solder ribbon and solder paste together. Finally, the laser adhesive film is removed after soldering. In this process, when ensuring close contact between the solder ribbon and the solder paste using the tooling, a laser adhesive film can be applied to the solder ribbon. Then, a vacuum is created between the laser adhesive film and the BC solar cell string to press the solder ribbon into the solder paste, achieving the desired tight contact.
[0058] In related technologies, solder paste can be printed onto BC solar cell strings using a solder paste stencil, such as... Figure 1 As shown, the mesh 01 of the solder paste stencil is usually rectangular, while the solder paste 02 printed on the pads 03 of the BC solar cell string has a rectangular structure. After drying, as shown... Figure 2 As shown, the surface of solder paste 02 is arched, resulting in an arc-shaped structure. This leads to a small contact area between solder ribbon 04 and solder paste 02. Furthermore, the surface of solder paste 02 is relatively smooth. When solder ribbon 04 is placed on the dried solder paste 02 or when it is subjected to pressure, it is easy for solder ribbon 04 to slip off the solder paste 02, causing it to shift and resulting in poor soldering. This, in turn, affects the performance of the BC solar cell string.
[0059] Taking a back-contact solar cell as an example, solder ribbons can be welded to the BC solar cell string using laser welding. The welding process may include: laying glass and front-side adhesive film on a table; arranging the BC solar cell string on the front-side adhesive film with the back of the BC solar cell string facing upwards, i.e., the side of the BC solar cell string with the solder pads facing upwards; printing solder paste on the solder pads and drying the solder paste; placing the solder ribbons on the solder paste on the BC solar cell string as required; covering with laser adhesive film and evacuating the vacuum to make the distance between the solder ribbons and the solder pads as close as possible to ensure welding effect; using laser line scanning welding to weld the solder ribbons to the solder pads; and removing the laser adhesive film after welding.
[0060] Since the positive and negative electrodes of a back-contact battery are both on the back, and the positive and negative electrode grid lines are arranged in an interdigital pattern, insulating adhesive needs to be printed on the grid lines to avoid short circuits. The height of the insulating adhesive is generally 25μm-40μm. To ensure metallization during soldering, solder paste is printed on the pads between the insulating adhesive. Under normal circumstances, the height of the solder paste after drying is about 80μm, which is 40μm-50μm higher than the height of the insulating adhesive. Figure 2 As shown, the solder paste 02 shrinks towards the center during the drying process, causing the dried solder paste 02 to arch and have an arc-shaped surface. The surface of the dried solder paste 02 is smooth, and the solder ribbons 04 arranged on it are easy to slip off, causing the solder ribbons 04 to shift.
[0061] In view of this, this application discloses a BC solar cell string and a BC photovoltaic module, which can prevent the solder strip from slipping off the dried solder paste during soldering, effectively avoid solder strip misalignment and resulting in cold solder joints, and improve the soldering quality of the solder strip.
[0062] The technical solution of this application will be further described below with reference to specific embodiments and accompanying drawings.
[0063] Figure 3 The diagram shown is a schematic representation of a solder paste stencil provided in an embodiment of this application, wherein one, Figure 3 A dashed frame in the diagram represents the area of a pad corresponding to a mesh opening. Figure 4 The diagram shown is a schematic representation of a mesh structure provided in an embodiment of this application. Figure 5 The diagram shown is a structural schematic of a solder paste pattern obtained by solder paste stencil printing according to an embodiment of this application. Figure 6 The diagram shown is a schematic representation of the structure of solder paste after drying, according to an embodiment of this application. Figure 7 The diagram shown is a schematic representation of a structure provided in this application, in which solder ribbon is placed on dried solder paste. Figure 8 The diagram shown is a structural schematic of a solder paste pattern obtained by solder paste stencil printing according to an embodiment of this application, when the pattern is offset relative to the pads. Figure 9 The diagram shown is a schematic representation of a dried solder paste that has shifted direction, provided in an embodiment of this application. Figure 10 The diagram shown is a schematic representation of a structure in this application where solder ribbon is placed on dried solder paste that has shifted. Figure 11 The diagram shown is a structural schematic of a BC solar cell string without solder strips according to an embodiment of this application. Please refer to it. Figures 3-11 As shown.
[0064] This embodiment provides a solder paste stencil 10 for printing solder paste 3 on the pads 5 of a BC solar cell string 20. The solder paste 3 is used to solder the solder ribbon 4 to the pads 5. The solder paste stencil 10 includes a body 1 and a plurality of mesh openings 2. The plurality of mesh openings 2 are arrayed on the body 1, and each mesh opening 2 corresponds to a pad 5. At least one partition 22 is provided in the mesh opening 2, and the mesh opening 2 is divided by the at least one partition 22 to form a plurality of sub-mesh openings 21. The plurality of sub-mesh openings 21 are arranged along a first direction (e.g., ...). Figure 4 The direction (as shown in x) is arranged such that when the solder strip 4 is soldered to the pad 5 of the BC solar cell string 20, the first direction is the width direction of the solder strip 4.
[0065] In this embodiment, by providing at least one dividing portion 22 within the mesh 2 of the solder paste stencil 10, the mesh 2 is divided into multiple sub-mesh 21. When solder paste 3 is printed from the solder paste stencil 10, the solder paste 3 can be printed onto a corresponding pad 5 through the multiple sub-mesh 21. The solder paste 3 is formed by combining multiple small sub-solder pastes 31, each of which has an arched surface after drying. Furthermore, the multiple sub-mesh 21 are arranged along a first direction, i.e., when the solder ribbon 4 is soldered to the pad 5 of the BC solar cell string 20, the multiple sub-mesh 21 are arranged along the width direction of the solder ribbon 4. This allows the solder ribbon 4 to contact the multiple sub-solder pastes 31 located on the pad 5 along the width direction of the solder ribbon 4 after it is placed on the dried solder paste 3. This ensures that multiple areas of the solder ribbon 4 can contact the solder paste 3, i.e., along the width direction of the solder ribbon 4, the solder paste 3 can be used for soldering. The strip 4 provides multiple support points, which effectively prevents the solder strip 4 from slipping off the solder paste 3, or from slipping off the solder paste 3 under pressure, thereby avoiding cold solder joints caused by the solder strip 4 slipping off the solder paste 3. This effectively improves the soldering quality of the solder strip 4 and is beneficial to the performance improvement of the BC solar cell string 20. Furthermore, by effectively preventing cold solder joints caused by the solder strip 4 slipping off the solder paste 3, the rework caused by cold solder joints of the solder strip 4 is effectively reduced, thus effectively improving the production yield of the BC solar cell string 20. On the other hand, compared with the method where the mesh 2 does not have a separator 22, that is, the solder paste 3 printed on the corresponding pad 5 of the mesh 2 is a solder paste pattern, the solder paste pattern printed through the mesh 2 of this application can effectively reduce the amount of solder paste used, thereby effectively reducing costs, while keeping the shape and size of the mesh 2 unchanged.
[0066] Furthermore, when misalignment occurs during the printing of solder paste 3 onto pad 5 via solder paste stencil 10, a larger portion of solder paste 3 is printed onto the blue film of the BC solar cell string 20. Since the wettability of solder paste 3 on the blue film is less than that on pad 5, the solder paste 3 shrinks more towards the center during the drying process. This results in a more pronounced arching of the dried solder paste 3 surface, leading to a higher height of solder paste 3. Figure 9 and Figure 10 As shown. Because the solder ribbon 4 can abut against multiple sub-solder pastes 31 located on the pad 5 along the width direction of the solder ribbon 4, and the solder paste 3 can provide multiple support points for the solder ribbon 4, it can still effectively prevent the solder ribbon 4 from slipping off the solder paste 3, or prevent the solder ribbon 4 from slipping off the solder paste 3 when under pressure, thereby avoiding the situation of cold solder joints caused by the solder ribbon 4 slipping off the solder paste 3, effectively improving the soldering quality of the solder ribbon 4, and benefiting the improvement of the performance of the BC solar cell string 20.
[0067] It should be understood that each mesh 2 is used to correspond to a solder pad 5, that is, a solder paste pattern can be printed on a corresponding solder pad 5 through a mesh 2. The solder paste pattern is formed by combining sub-solder paste 31 patterns printed through multiple sub-mesh 21 within the mesh 2.
[0068] The number of the aforementioned partitions 22 can be one, two, or more, and is not limited here.
[0069] Furthermore, the partition 22 can be integrally formed with the main body 1, making the production of the solder paste stencil 10 simpler and easier to achieve.
[0070] Please refer to Figure 4 As shown, optionally, the mesh 2 includes two opposing mesh walls 23, the mesh walls 23 extending along a first direction, and the partition portion 22 extending along a second direction (e.g., Figure 4 The second direction is the length direction of the solder strip 4 when the solder strip 4 is soldered to the pad 5 of the BC solar cell string 20. The second direction is the direction of the length of the solder strip 4 when the solder strip 4 is soldered to the pad 5 of the BC solar cell string 20.
[0071] Therefore, the structure of the mesh 2 and the separator 22 is relatively simple and easy to implement, which reduces the production cost of the solder paste stencil 10. Furthermore, along the length of the solder ribbon 4, the multiple sub-solder pastes 31 formed by printing through multiple sub-mesh 21 can be aligned with each other, making it easy to control the amount of solder paste used by setting the size of the sub-mesh 21, which is beneficial for cost control.
[0072] Please refer to Figure 4 As shown, multiple sub-mesh holes 21 are arranged at equal intervals along the first direction.
[0073] Therefore, the fabrication of multiple sub-mesh holes 21 can be made relatively simple and easy to implement.
[0074] Of course, in other embodiments, the spacing between any two adjacent sub-mesh holes 21 along the first direction may not be the same, or the spacing between some adjacent sub-mesh holes 21 along the first direction may be the same, while the spacing between other adjacent sub-mesh holes 21 may be different. This is not limited here, and can be set according to the actual situation.
[0075] Figure 12 The diagram shown is a schematic representation of the structure of the second type of mesh provided in an embodiment of this application. Figure 12 The diagram shown is a structural schematic of the third type of mesh provided in an embodiment of this application. Figure 13 The diagram shown is a structural schematic of the fourth type of mesh provided in the embodiments of this application. Please refer to it. Figure 4 and Figures 12-14 As shown.
[0076] Optionally, the sub-mesh 21 can be any one of a rectangular structure, a parallelogram structure, a trapezoidal structure, or a circular structure.
[0077] This allows the sub-mesh 21 to have a more regular shape, making the structure of the solder paste stencil 10 simpler and easier to manufacture, further reducing the manufacturing cost of the solder paste stencil 10, and enabling the solder paste stencil 10 to have better applicability.
[0078] In one mesh 2, the shapes of multiple sub-mesh 21 can be the same, so that the production of the screen can be simpler and easier to achieve; or they can be different, so that the shape of the sub-mesh 21 can be flexibly set as needed, and no limitation is made here.
[0079] Of course, the sub-mesh 21 can also be other shapes, such as elliptical structures, triangular structures, and structures combining rectangles and semicircles, etc., and is not limited here.
[0080] The shape of the partition 22 can also be any of the following: rectangular structure, parallelogram structure, trapezoidal structure, circular structure, etc., and is not limited here.
[0081] Furthermore, when there are two or more partitions 22, the shapes of the two or more partitions 22 can be the same, so that the production of the screen can be simpler and easier to achieve; they can also be different, which is not limited here.
[0082] In some embodiments, the number of sub-mesh 21 may be three, and the number of partitions 22 may be two.
[0083] Therefore, the number of printed sub-solder paste 31 is three, so that the three different areas of the solder ribbon 4 along its own width direction can respectively abut against the three sub-solder paste 31. This makes the solder ribbon 4 less likely to slip off the solder paste 3, and also ensures that the soldering between the solder ribbon 4 and the solder pad 5 has sufficient solder paste 3, thereby improving the soldering quality between the solder ribbon 4 and the solder pad 5.
[0084] Of course, the number of sub-mesh 21 can also be two, four or other numbers, and the number of corresponding dividers 22 can also be one, three or other numbers, which is not limited here.
[0085] In other embodiments, along the second direction, the width of the sub-mesh 21 is greater than the width of the pad 5.
[0086] This allows the printed solder paste 3 to have a larger contact area with the pad 5, thereby enabling better soldering quality between the solder ribbon 4 and the pad 5 and further reducing the chance of cold solder joints on the solder ribbon 4.
[0087] The difference between the width of the sub-mesh 21 and the width of the pad 5 can be 15mm to 25mm, so that when the solder paste stencil 10 is printed with solder paste 3, even if the solder paste stencil 10 is offset along the second direction, the printed solder paste 3 and the pad 5 can still have a large contact area. At the same time, it is not easy to use too much solder paste, which is beneficial to cost control.
[0088] For example, the difference between the width of the sub-mesh 21 and the width of the pad 5 can be 15mm, 20mm, 25mm, etc., and is not limited here.
[0089] In some embodiments, along the first direction, the length of the sub-mesh 21 is greater than the length of the separator 22.
[0090] Therefore, along the first direction, the sub-solder paste 31 printed through the sub-mesh 21 can still have a certain size after drying, so that when the solder ribbon 4 is soldered, there can be sufficient solder paste 3 to ensure the soldering quality between the solder ribbon 4 and the solder pad 5.
[0091] In addition, in a mesh 2, the ratio of the sum of the areas of multiple sub-mesh 21 to the sum of the areas of at least one partition 22 ranges from 1.5 to 3.5.
[0092] Therefore, the solder paste 3 printed can meet the soldering requirements between the solder ribbon 4 and the solder pad 5, resulting in high-quality soldering while also preventing the amount of solder paste printed from being too large, which is beneficial for cost control.
[0093] The ratio of the sum of the areas of the multiple sub-mesh 21 to the sum of the areas of at least one partition 22 can be 1.5, 2, 3.5, etc., and is not limited here.
[0094] For example, in a mesh 2, the sum of the areas of multiple sub-mesh 21 can be 120000 mm². 2 The sum of the areas of at least one partition 22 can be 40000 mm². 2 The ratio between the two is 3.
[0095] When the ratio of the sum of the areas of multiple sub-mesh 21 to the sum of the areas of at least one partition 22 in a mesh 2 is less than 1.5, although the consumption of solder paste can be effectively reduced, it is easy to result in too little solder paste obtained from printing, which may cause poor soldering between the solder ribbon 4 and the solder pad 5, which is not conducive to improving the soldering quality of the solder ribbon 4.
[0096] When the ratio of the sum of the areas of multiple sub-mesh 21 to the sum of the areas of at least one partition 22 in a mesh 2 is greater than 3.5, although the amount of solder paste 3 obtained by printing is sufficient to ensure that the solder ribbon 4 and the solder pad 5 have good conductivity and soldering reliability, it is easy to cause a large consumption of solder paste, which is not conducive to cost control.
[0097] In some embodiments, along the first direction, the size of the mesh 2 is 600mm to 850mm, the size of the sub-mesh 21 is 150mm to 250mm, and the size of the partition 22 is 50mm to 150mm.
[0098] Therefore, the size of the solder paste 3 obtained by printing through the mesh 2 can be better matched with the size of the corresponding pad 5; at the same time, the amount of solder paste 3 obtained by printing can be sufficient, so that the soldering quality between the solder ribbon 4 and the pad 5 can be better; and the size of the separator 22 can be kept from being too small, so that the separator 22 can have high structural strength, so that the separator 22 is not easily damaged due to stress during the printing process, effectively improving the printing quality and effectively reducing the loss of solder paste stencil 10, thereby further reducing the production cost of BC solar cell string 20.
[0099] Along the first direction, the size of the mesh 2 can be 600mm, 800mm, 850mm, etc., and is not limited here.
[0100] Along the first direction, the size of the sub-mesh 21 can be 150mm, 200mm, 250mm, etc., and is not limited here.
[0101] Along the first direction, the size of the partition 22 can be 50mm, 100mm, 150mm, etc., and is not limited here.
[0102] For example, when the mesh 2 is a rectangular structure, the number of sub-mesh 21 is three, the number of partitions 22 is two, and the three sub-mesh 21 and the two partitions 22 are all rectangular structures. When the three sub-mesh 21 are all the same size and the two partitions 22 are all the same size, the size of the mesh 2 along the first direction can be 800mm, the size of the sub-mesh 21 is 200mm, and the size of the partition 22 is 100mm.
[0103] This application also discloses a BC solar cell string; please refer to [reference needed]. Figures 5 to 11As shown, the BC solar cell string 20 includes multiple BC solar cell bodies 6 and solder paste 3. The BC solar cell body 6 has pads 5; the solder paste 3 is disposed on the pads 5 and is used for soldering the solder ribbon 4 to the pads 5. The solder paste 3 includes multiple sub-solder pastes 31, which are arranged along a first direction. When the solder ribbon 4 is soldered to the pads 5, the first direction is the width direction of the solder ribbon 4.
[0104] In this embodiment, solder paste 3 is applied to pad 5. Solder paste 3 includes multiple sub-solder pastes 31, allowing multiple sub-solder pastes 31 to be printed on pad 5. Each sub-solder paste 31 has an arched surface after drying. The solder ribbon 4 is soldered to pad 5 via multiple sub-solder pastes 31 arranged along a first direction. The first direction is the width direction of the solder ribbon 4 when it is soldered to pad 5. That is, when the solder ribbon 4 is soldered to the BC solar cell string 20, after placing the solder ribbon 4 on the dried solder paste 3, along the width direction of the solder ribbon 4, the solder ribbon 4 can abut against the multiple sub-solder pastes 31 located on pad 5, so that multiple areas of the solder ribbon 4 can abut against the solder paste 3. In other words, along the width direction of the solder ribbon 4, the solder paste 3 can provide multiple support points for the solder ribbon 4. This effectively prevents the solder ribbon 4 from slipping off the solder paste 3, or from slipping off the solder ribbon 4 under pressure, thus avoiding cold solder joints caused by the solder ribbon 4 slipping off the solder paste 3. This effectively improves the soldering quality of the solder ribbon 4, which is beneficial to the performance of the BC solar cell string 20. Furthermore, by effectively preventing cold solder joints caused by the solder ribbon 4 slipping off the solder paste 3, the probability of cold solder joints of the solder ribbon 4 is greatly reduced, thereby effectively reducing the need for rework due to cold solder joints of the solder ribbon 4 and effectively improving the production yield of the BC solar cell string 20. On the other hand, compared with the method of printing a solder paste pattern on the solder pad 5, the solder paste pattern printed by this application can effectively reduce the amount of solder paste 3 used while keeping the shape and size of the solder paste 3 unchanged, thereby effectively reducing costs.
[0105] Additionally, when solder paste 3 is misaligned during printing on pad 5, a larger portion of solder paste 3 is printed onto the blue film of the BC solar cell string 20. Since the wettability of solder paste 3 on the blue film is less than that on pad 5, the solder paste 3 shrinks more towards the center during drying, resulting in a more pronounced arching of the dried solder paste 3 surface and a higher height. Figure 9 and Figure 10As shown. Because the solder ribbon 4 can abut against multiple sub-solder pastes 31 located on the pad 5 along the width direction of the solder ribbon 4, and the solder paste 3 can provide multiple support points for the solder ribbon 4, it can still effectively prevent the solder ribbon 4 from slipping off the solder paste 3, or prevent the solder ribbon 4 from slipping off the solder paste 3 when under pressure, thereby avoiding the situation of cold solder joints caused by the solder ribbon 4 slipping off the solder paste 3, effectively improving the soldering quality of the solder ribbon 4, and benefiting the improvement of the performance of the BC solar cell string 20.
[0106] The number of pads 5 on the BC solar cell string 20 can be multiple, such as two, three or more. The number of solder paste 3 corresponds to the number of pads 5, and each solder paste 3 includes multiple sub-solder pastes 31, that is, a pad 5 can be printed with multiple sub-solder pastes 31.
[0107] It is understood that the solder paste 3 on the pad 5 can be obtained by printing the solder paste stencil 10 described in the above embodiments.
[0108] Please refer to Figure 5 As shown, optionally, the solder paste 3 includes two opposing sides 32 extending along a first direction, and there is a gap 33 between two adjacent sub-solder pastes 31 extending along a second direction, which is the length direction of the solder strip 4 when the solder strip 4 is soldered to the pad 5.
[0109] Therefore, along the length of the solder strip 4, multiple sub-solder pastes 31 can be aligned with each other, making it easy to control the amount of solder paste 3 used by controlling the size of the multiple sub-solder pastes 31, which is beneficial for cost control, and also makes the structure of the sub-solder pastes 31 simpler and easier to print.
[0110] It should be understood that the two sides 32 of the solder paste 3 are formed by combining the sides 32 of a plurality of sub-solder pastes 31 extending along the first direction, and the sides 32 of the plurality of sub-solder pastes 31 extending along the first direction are approximately flush with the length of the solder strip 4.
[0111] Optionally, a plurality of sub-solder pastes 31 are arranged at equal intervals along a first direction.
[0112] Therefore, the printing of multiple sub-solder pastes 31 can be relatively simple and easy to implement.
[0113] Of course, in other embodiments, the spacing between any two adjacent sub-solder pastes 31 along the first direction may also be different, or the spacing between some adjacent sub-solder pastes 31 along the first direction may be the same, while the spacing between other adjacent sub-solder pastes 31 may be different. This is not limited here, and can be set according to the actual situation.
[0114] In addition, along the first direction, the length of the sub-solder paste 31 is greater than the interval 33 between two adjacent sub-solder pastes 31.
[0115] Therefore, along the first direction, the printed solder paste 31 can still have a certain size after drying, so that when the solder ribbon 4 is soldered, there can be sufficient solder paste 3 to ensure the soldering quality between the solder ribbon 4 and the solder pad 5.
[0116] Optionally, the ratio of the sum of the projected areas of the plurality of sub-solder pastes 31 on the BC solar cell body 6 to the sum of the areas of the spacings 33 in the solder paste 3 is in the range of 1.5 to 3.5.
[0117] Therefore, the solder paste 3 printed can meet the soldering requirements between the solder ribbon 4 and the solder pad 5, resulting in high-quality soldering while also preventing the amount of solder paste 3 printed from being too large, which is beneficial for cost control.
[0118] It should be understood that the sum of the projected areas of multiple sub-solder pastes 31 on the BC solar cell body 6 refers to the sum of the areas of the orthographic projections of multiple sub-solder pastes 31 on the BC solar cell body 6, that is, the sum of the areas occupied by multiple sub-solder pastes 31 on the BC solar cell body 6.
[0119] It should also be understood that the sum of the areas of the intervals 33 in the solder paste 3 refers to the sum of the areas of the intervals 33 between any two adjacent sub-solder pastes 31 in the solder paste 3. For example, when there are three sub-solder pastes 31, there can be two intervals 33, and the sum of the areas of these two intervals 33 is the sum of the areas of the intervals 33 in the solder paste 3.
[0120] The ratio of the sum of the projected areas of the multiple sub-solder pastes 31 on the BC solar cell body 6 to the sum of the areas of the spacing 33 in the solder paste 3 can be 1.5, 2, 3.5, etc., and is not limited here.
[0121] For example, in a solder paste 3, the sum of the areas of multiple sub-solder pastes 31 can be 120000 mm². 2 The sum of the areas of at least one interval of 33 can be 40000 mm². 2 The ratio between the two is 3.
[0122] When the ratio of the sum of the projected areas of multiple sub-solder pastes 31 on the BC solar cell body 6 to the sum of the areas of the spacing 33 in the solder paste 3 is less than 1.5, although the consumption of solder paste 3 can be effectively reduced, it is easy to result in too little solder paste 3 obtained from printing, which makes it easy for the solder ribbon 4 and the pad 5 to have a cold solder joint, which is not conducive to improving the soldering quality of the solder ribbon 4.
[0123] When the ratio of the sum of the projected areas of multiple sub-solder pastes 31 on the BC solar cell body 6 to the sum of the areas of the spacing 33 in the solder paste 3 is greater than 3.5, although the amount of solder paste 3 obtained by printing is sufficient so that the solder ribbon 4 and the solder pad 5 can have good conductivity and soldering reliability, it is easy to cause a large consumption of solder paste 3, which is not conducive to cost control.
[0124] Figure 15 The diagram shown is a structural schematic of the solder paste pattern obtained by the second type of printing according to an embodiment of this application. Figure 16 The diagram shown is a structural schematic of the solder paste pattern obtained by the third type of printing according to an embodiment of this application. Figure 17 The diagram shown is a structural schematic of the solder paste pattern obtained by the fourth type of printing according to an embodiment of this application. Please refer to it. Figure 5 and Figures 15-17 As shown.
[0125] In some embodiments, the sub-solder paste 31 is any one of a rectangular structure, a parallelogram structure, a trapezoidal structure, or a circular structure.
[0126] Therefore, the shape of the solder paste 31 can be more regular, the structure of the solder paste 3 can be simpler and easier to manufacture, further reducing the printing cost of the solder paste 3, and the structure of the solder paste stencil 10 for printing the solder paste 3 can be simpler, making the solder paste stencil 10 more applicable.
[0127] In one solder paste 3, the shapes of multiple sub-solder pastes 31 can be the same, so that the printing of sub-solder pastes 31 can be simpler and easier to achieve; or they can be different, so that the shape of sub-solder pastes 31 can be flexibly set as needed, and no limitation is made here.
[0128] Of course, the solder paste 31 can also be in other shapes, such as an elliptical structure, a triangular structure, or a combination of a rectangle and a semicircle, etc., and is not limited here.
[0129] In other embodiments, the number of sub-solder paste 31 is 2 to 4.
[0130] This allows the solder ribbon 4 to come into contact with 2 to 4 sub-solder pastes 31 in three different areas along its width direction. This ensures that the solder ribbon 4 does not easily slip off the solder paste 3, and that there is a sufficient amount of solder paste 3 between the solder ribbon 4 and the pad 5, thereby improving the soldering quality between the solder ribbon 4 and the pad 5.
[0131] The number of solder paste 31 can be two, three or four, and the number of corresponding intervals 33 can also be one, two or three, which is not limited here.
[0132] In some embodiments, along the second direction, the width of the sub-solder paste 31 is greater than the width of the pad 5, and the second direction is the length direction of the solder strip 4.
[0133] This allows the printed solder paste 3 to have a larger contact area with the pad 5, thereby enabling better soldering quality between the solder ribbon 4 and the pad 5 and further reducing the chance of cold solder joints on the solder ribbon 4.
[0134] The difference between the width of the sub-solder paste 31 and the width of the pad 5 can be 15mm to 25mm. This ensures that even if multiple sub-solder pastes 31 are offset along the second direction when the solder paste 3 is printed by the solder paste stencil 10, the printed solder paste 3 and the pad 5 can still have a large contact area. At the same time, it is not easy to print too much solder paste 3, which is beneficial for cost control.
[0135] For example, the difference between the width of the sub-solder paste 31 and the width of the pad 5 can be 15mm, 20mm, 25mm, etc., and is not limited here.
[0136] In other embodiments, along the first direction, the solder paste 3 has a size of 600 mm to 850 mm, and the sub-solder paste 31 has a size of 150 mm to 250 mm.
[0137] This allows the size of the printed solder paste 3 to be more compatible with the size of the corresponding pad 5; at the same time, it also ensures that the amount of solder paste 3 is sufficient, so that the soldering quality between the solder ribbon 4 and the pad 5 can be better.
[0138] In the first direction, the size of solder paste 3 can be 600mm, 800mm, 850mm, etc., and is not limited here.
[0139] Along the first direction, the size of the sub-solder paste 31 can be 150mm, 200mm, 250mm, etc., and is not limited here.
[0140] For example, when the solder paste 3 is a rectangular structure, the number of sub-solder pastes 31 is three, and all three sub-solder pastes 31 are rectangular structures. When the dimensions of the three sub-solder pastes 31 are the same, along the first direction, the size of the solder paste 3 can be 800mm, and the size of the sub-solder paste 31 can be 200mm.
[0141] This application also discloses a BC photovoltaic module, comprising the BC solar cell string 20 described in any of the above embodiments.
[0142] In this embodiment, the BC solar cell string 20 in the BC photovoltaic module is any of the BC solar cell string 20 in the above embodiments. Therefore, when the solder ribbon 4 is placed on the dried solder paste 3 and pressure is applied to the solder ribbon 4, the solder ribbon 4 is not easy to slip off the dried solder paste 3, which effectively avoids the situation of cold solder joints caused by the solder ribbon 4 slipping off the solder paste 3. This effectively improves the welding quality between the solder ribbon 4 and the pad 5, which is conducive to improving the performance of the BC photovoltaic module. It can also effectively reduce the rework caused by the cold solder joint of the solder ribbon 4, improve production efficiency, and reduce costs.
[0143] Furthermore, since the BC solar cell string 20 in the BC photovoltaic module in this embodiment is any of the BC solar cell string 20 in the above embodiments, the BC solar cell string 20 in this embodiment has the technical effects of the BC solar cell string 20 in the above embodiments. Since the technical effects of the BC solar cell string 20 have been fully explained in the above embodiments, they will not be repeated here.
[0144] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A string of BC solar cells, characterized in that, include: Multiple BC solar cell bodies, wherein the BC solar cell bodies are provided with solder pads; Solder paste, which is disposed on the pads and used for soldering ribbons to the pads, includes a plurality of sub-solder pastes arranged along a first direction, wherein the first direction is the width direction of the solder ribbons when the solder ribbons are soldered to the pads.
2. The BC solar cell string of claim 1, wherein, The solder paste includes two opposing sides extending along a first direction, and there is a gap between two adjacent sub-solder pastes extending along a second direction, which is the length direction of the solder strip when it is soldered to the pad.
3. The BC solar cell string of claim 2, wherein, The plurality of said sub-solder pastes are arranged at equal intervals along the first direction.
4. The BC solar cell string according to claim 2, characterized in that, Along the first direction, the length of the sub-solder paste is greater than the interval between two adjacent sub-solder pastes.
5. The BC solar cell string according to claim 2, characterized in that, The ratio of the sum of the areas of the projections of the plurality of sub-solder pastes onto the BC solar cell body to the sum of the areas of the intervals in the solder paste ranges from 1.5 to 3.
5.
6. The BC solar cell string according to any one of claims 1-5, characterized in that, The solder paste can be any one of the following structures: rectangular, parallelogram, trapezoidal, or circular.
7. The BC solar cell string according to any one of claims 1-5, characterized in that, The number of sub-solder pastes is 2 to 4.
8. The BC solar cell string according to any one of claims 1-5, characterized in that, Along the second direction, the width of the sub-solder paste is greater than the width of the pad, and the second direction is the length direction of the solder strip when the solder strip is soldered to the pad.
9. The BC solar cell string according to any one of claims 1-5, characterized in that, Along the first direction, the size of the solder paste is 600mm to 850mm, and the size of the sub-solder paste is 150mm to 250mm.
10. A BC photovoltaic module, characterized in that, include: The BC solar cell string according to any one of claims 1-9.