Solar cell string and solar cell module

Abstract

The present disclosure relates to the technical field of photovoltaic module manufacturing. Provided are a solar cell string and a solar cell module. A busbar of the solar cell string in the embodiments of the present application comprises a plurality of welding portions and a non-welding portion for connecting two adjacent welding portions, wherein the welding portions are welded to at least one tabbing ribbon, thereby ensuring the effect of contact welding based on tin layer melting; a gap is provided between the non-welding portion and the at least one tabbing ribbon, such that stress generated by the thermal expansion of the busbar and the tabbing ribbon during busbar welding can be released, thereby preventing a welding strip on the back face of each cell from being pulled to shift due to the busbar contracting after being welded. Alternatively, the busbar of the solar cell string in the embodiments of the present application comprises several fixed sites arranged at intervals in the direction of length and a non-fixed section for connecting two adjacent fixed sites, wherein the fixed sites are fixedly connected to tabbing ribbons therebelow, and the non-fixed sections are in contact with at least some of the tabbing ribbons therebelow, thereby reducing the material consumption of a single cell and decreasing the phenomena of being pulled to shift.

Description

Solar cell string and solar cell module

[0001] This application claims priority to Chinese patent application No. 202322368917.4, filed with the Chinese Patent Office on August 31, 2023, and entitled “A Solar Cell String and Solar Cell Module”, and claims priority to Chinese patent application No. 202421593306.8, filed with the Chinese Patent Office on July 5, 2024, and entitled “A Solar Cell String and Solar Cell Module”. All of the above contents are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of photovoltaic module manufacturing, and in particular to a solar cell string and a solar cell module. Background Art

[0003] Currently, conventional shingled solar cell modules are designed for full parallel connection. The current of a single cell string is small, which is 1 / 5 to 1 / 6 of the current of the entire cell. At the same time, three bypass diodes are used in parallel in the circuit, and the electrical design of the bypass diodes is achieved by spot welding the busbars corresponding to the bypass diodes to the PADs on the back of the cell. Traditional half-cell modules, on the other hand, use a series-parallel connection of cells and three bypass diodes in parallel in the circuit. The electrical design of the bypass diodes is achieved by directly welding the busbars corresponding to the bypass diodes to the interconnection bars. The interconnection bars are designed to extend 5 to 10 mm beyond the cell and overlap with the busbars by 50% to 100%.

[0004] However, this method of spot welding the busbar to the back pad of the cell has the following problems: ① The process window is narrow. In order to ensure the welding effect, auxiliary welding materials such as solder paste or flux need to be added, which will increase the material consumption; ② Silver paste is used on the back pad of the cell to ensure the welding effect. The amount of silver on the back of the single cell needs to be increased by 10 to 20 mg, which will also reduce the battery efficiency; ③ Increasing the back composite reduces the battery efficiency by 0.03% to 0.08%; ④ Because the busbar is in direct contact with the cell for welding, as the cell thinner, the cell cracks and other defects are more likely to occur. An increase of 0.02% to 0.05%; the bypass diode design in the middle of the traditional half-cell module is achieved by directly welding the bus bar corresponding to the bypass diode to the interconnection bar. The interconnection bar design exceeds the battery cell by 5 to 10 mm and overlaps with the bus bar by 50% to 100%; a 10mm to 20mm bus bar and interconnection bar welding area is left in the middle of the module. At the same time, because the middle bus bar is welded to the interconnection bars on both sides, the head and tail battery strings of the module need to be staggered by about 0.5mm, and the welding of the interconnection bars on both sides interferes with each other, and the module efficiency drops by 0.1% to 0.2%.

[0005] In addition, as the film flows during the lamination process of photovoltaic modules, the battery strings are slightly displaced, causing the head and tail interconnecting bars and bus bars of the battery strings to be pulled and twisted, and the appearance of the modules is degraded.

[0006] Summary of the Invention

[0007] The present invention aims to provide a solar cell string and solar cell module in which busbars are directly welded to interconnecting bars via welding sections, ensuring effective contact welding due to melting of the tin layer. A gap is provided between the non-welded section and at least one interconnecting bar to relieve stress caused by thermal expansion and contraction of the busbars and interconnecting bars during welding, preventing post-weld busbar shrinkage that could cause the solder ribbons on the back of the cell to be pulled and offset, thereby improving the overall aesthetics of the module. This approach addresses the aforementioned cost, efficiency, and process shortcomings associated with direct welding of the busbars corresponding to the bypass diodes in current shingled solar cell modules to the pads on the back of the cell, as well as technical issues such as poor welding quality, module efficiency, and post-lamination appearance caused by the 10-20mm central welding area where the busbars connect to the interconnecting bars in half-cell modules.

[0008] The purpose of the embodiments of the present application is to provide another solar cell string and solar cell module, which does not require PAD points to be set on the surface, nor does it require the addition of auxiliary welding materials, which can reduce the material consumption of single-cell cells and improve battery efficiency; the fixed points of the bus bar are fixedly connected to the interconnecting bars, the connection effect of the bus bar is good, and the occurrence of adverse phenomena is reduced; the non-fixed section of the bus bar is in contact with the interconnecting bar but is not fixed, which can reduce the pulling and twisting phenomenon caused by slight displacement of the battery string, and improve the overall aesthetics of the module.

[0009] In a first aspect, an embodiment of the present application provides a solar cell string, comprising: a bus bar, an interconnect bar, and a cell;

[0010] The plurality of battery cells are arranged in sequence along a preset direction, and adjacent battery cells are connected via the interconnection strips;

[0011] The busbar is disposed on the battery cell and extends along the arrangement direction of the battery cell;

[0012] Along the extension direction of the busbar, the busbar includes a plurality of welding portions and a non-welding portion connecting two adjacent welding portions. The welding portion is welded to at least one interconnecting bar, and a gap is provided between the non-welding portion and at least one interconnecting bar.

[0013] As a further technical solution, the non-welded portion is arched relative to the two adjacent welded portions.

[0014] As a further technical solution, the arched shape of the non-welded portion is an arc, a triangle, a trapezoid or a square.

[0015] As a further technical solution, the connection between the welding portion and the non-welding portion is configured as a chamfer, a right angle or a rounded corner.

[0016] As a further technical solution, the arch height of the non-welded portion is h, and 0<h≤2mm.

[0017] As a further technical solution, the battery cell has a front side and a back side, the bus bar is located on the back side of the battery cell and is welded to the back side of the interconnection bar.

[0018] As a further technical solution, the busbar has a thickness of 0.05 mm to 0.15 mm.

[0019] As a further technical solution, the width of the busbar is 5 mm-15 mm.

[0020] As a further technical solution, the cell is formed by cutting a 182mm silicon wafer into two or three pieces;

[0021] Alternatively, the cell is formed by cutting a 210 mm silicon wafer into two or three pieces.

[0022] In a second aspect, an embodiment of the present application provides a solar cell assembly comprising three bypass diodes and six parallel-arranged solar cell strings.

[0023] The three solar cell strings on the left of the six solar cell strings are connected in parallel to form a first group, the three solar cell strings on the right are connected in parallel to form a second group, and the first group and the second group are connected in series;

[0024] The three bypass diodes are connected in parallel via the bus bar.

[0025] Compared with the existing technology, the solar cell string and solar cell module provided by this application have the following technical advantages:

[0026] The solar cell string provided in the present application includes: a bus bar, an interconnecting bar and a cell; a plurality of cell cells are arranged in sequence along a preset direction, and adjacent cell cells are connected by interconnecting bars; the bus bar is provided on the cell cells and extends along the arrangement direction of the cell cells; along the extension direction of the bus bar, the bus bar includes a plurality of welding portions and a non-welding portion connecting two adjacent welding portions, the welding portion is welded to at least one interconnecting bar, and the non-welding portion is spaced apart from at least one interconnecting bar.

[0027] The busbars are mounted on the cell and directly welded to the interconnecting bars via the welding section, ensuring contact welding with the melted tin layer. A gap is provided between the non-welded section and at least one interconnecting bar to relieve stress caused by thermal expansion and contraction of the busbars and interconnecting bars during welding, preventing post-weld busbar shrinkage that could cause the solder ribbon on the cell's backside to be pulled and offset. Compared to conventional shingled solar cell modules, where the busbars are directly welded to the cell's backside pads, this arrangement offers a lower fragmentation rate, a wider process window, and eliminates the need for additional auxiliary welding materials such as solder paste or flux. The amount of back silver is also significantly reduced, improving cell efficiency and minimizing hidden cracking even with thinner cells. Compared to conventional half-cell module welding, this arrangement eliminates the need for a 10mm to 20mm welding area between the busbars and interconnecting bars in the middle of the module. Furthermore, the head and tail cell strings of the module do not need to be misaligned during welding, and the interconnecting bars on both sides do not interfere with each other, improving module efficiency. It also relieves the pulling force on the cell strings caused by film flow during the lamination process, reducing the risk of hidden cracking and fragmentation, and improving overall aesthetics.

[0028] The solar cell assembly provided in the present application includes the above-mentioned solar cell string. Therefore, the technical advantages and effects achieved by it include the technical advantages and effects achieved by the above-mentioned solar cell string, which will not be elaborated here.

[0029] In a third aspect, an embodiment of the present application provides a solar cell string comprising at least two sequentially arranged solar cells, wherein two adjacent solar cells are connected by a plurality of interconnecting bars, and a bus bar is provided on all the interconnecting bars connected to at least one of the solar cells;

[0030] The busbar includes a plurality of fixed sites spaced apart along the length direction and a non-fixed segment connecting two adjacent fixed sites. The fixed sites are fixedly connected to the interconnection bar below them, and at least a portion of the non-fixed segments are laid on the interconnection bar. The non-fixed segments are not fixedly connected to the interconnection bar below them, and the non-fixed segments are in contact with at least a portion of the interconnection bars below them.

[0031] In the above implementation process, the battery cells are connected to the busbars through the interconnecting bars. There is no need to set PAD points on the surface of the battery cells, nor is there any need to add auxiliary welding materials such as solder paste or flux. Therefore, the process window is large, and the material consumption of the single battery cell can be reduced, and the battery efficiency is improved. The fixed points of the busbars are fixedly connected to the corresponding interconnecting bars, and the non-fixed sections of the busbars are in contact with the corresponding interconnecting bars. Not only do the busbars have many contact points and good connection effects, which can reduce heat problems, but the overall structure is relatively flat, and the stress on the battery cells is relatively small, which can reduce the occurrence of adverse phenomena. Even if the battery cells are thin, the overall fragmentation rate during lamination is low. In addition, the above-mentioned arrangement and connection method of the interconnecting bars and busbars can release the pulling force of the film flow on the battery string during the lamination process, reduce the pulling and twisting phenomenon of the interconnecting bars and busbars, and improve the overall aesthetics of the component.

[0032] In a possible implementation, the bus bar is located on the battery, and each of the fixing points is fixedly connected to a corresponding position of the battery cell via the interconnection bar thereunder.

[0033] In the above implementation process, the bus bar is located on the battery and is fixedly connected to the interconnection bar which is also located on the battery. The fixed connection effect between the bus bar and the interconnection bar is good.

[0034] In a possible implementation, each of the fixing sites is fixedly connected to one of the interconnection bars thereunder.

[0035] In the above implementation process, each fixed location is fixedly connected to an interconnection bar, which makes it easy to achieve a fixed connection between the bus bar and the interconnection bar.

[0036] In a possible implementation, the number of the interconnection bars arranged below the non-fixed segments on the interconnection bars is 1 to 3.

[0037] In the above implementation process, the number of fixing sites can be controlled to achieve a good fixing connection effect between the bus bar and all interconnection bars.

[0038] In a possible implementation, the non-fixed segment mounted on the interconnection bar contacts all the interconnection bars thereunder.

[0039] In the above implementation process, the connection effect between the non-fixed section of the bus bar and the interconnection bar is good, and the bus bar is not easily broken during lamination.

[0040] In a possible implementation, at least a portion of the non-fixed segments located between adjacent interconnecting bars are recessed toward the battery cell.

[0041] In the above implementation process, the recessed position of the non-fixed section of the busbar is equivalent to a reserved free section, which can release the stress generated by the thermal expansion and contraction of the busbar (for example, when the busbar is welded to the interconnecting bar), and prevent the pulling and displacement caused by the contraction of the busbar. Therefore, the busbar is not easy to break and does not affect the lamination process.

[0042] In a possible implementation, a portion of the non-fixed segment in contact with the interconnection bar has a folded portion, and the folded portion is not higher than a surface of the bus bar.

[0043] In the above implementation process, the folded portion of the non-fixed segment of the busbar is equivalent to a free segment, so that the entire busbar is not easily broken and does not affect the lamination process.

[0044] In a possible implementation, the busbar is made of tinned copper strip, has a thickness of 0.05 to 0.15 mm, and a width of 5 to 15 mm.

[0045] The interconnection bar is made of tinned copper strip, and the diameter of the interconnection bar is 0.15-0.3 mm.

[0046] In the above implementation process, the fixed position can be directly welded to the interconnection bar, which can ensure the melting of the tin layer and the contact welding effect, and can also improve the contact effect between the non-fixed segment and the bus bar.

[0047] In a fourth aspect, an embodiment of the present application provides a solar cell assembly, comprising a plurality of solar cell strings provided in the third aspect, wherein the bus bars of all the solar cell strings are connected in sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0049] FIG1 is a schematic diagram of welding a bus bar with chamfers and an interconnection bar provided by the first embodiment;

[0050] FIG2 is a schematic diagram of welding a bus bar with rounded corners and an interconnection bar provided by the first embodiment;

[0051] FIG3 is a schematic diagram of the structure of a solar cell string provided by the first embodiment;

[0052] FIG4 is a schematic diagram of a solar cell assembly circuit according to a second embodiment;

[0053] FIG5 is a schematic structural diagram of a solar cell string provided by a third embodiment;

[0054] FIG6 is a schematic diagram of the middle structure of FIG5;

[0055] FIG7 is a schematic structural diagram of the battery cell with bus bars in FIG6 ;

[0056] FIG8 is a schematic structural diagram of FIG7 from another perspective;

[0057] FIG9 is a schematic structural diagram of a solar cell string provided with bus bars according to a fourth embodiment;

[0058] FIG10 is a schematic structural diagram of a solar cell string provided with bus bars according to the fifth embodiment;

[0059] FIG11 is a schematic structural diagram of a solar cell assembly provided in the sixth embodiment.

[0060] Icons: 1-solar cell string; 2-bus bar; 3-interconnect bar; 4-cell; 5-welding part; 6-non-welding part; 7-chamfer; 8-rounded corner; 9-bypass diode;

[0061] 100 - battery string; 110 - battery cell; 120 - interconnection bar; 130 - bus bar; 131 - fixed site; 132 - first non-fixed segment; 133 - second non-fixed segment. DETAILED DESCRIPTION

[0062] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0064] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. All other embodiments derived by persons of ordinary skill in the art based on the embodiments in this application without creative effort are also within the scope of protection of this application.

[0065] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0066] In the description of this application, it should be noted that the terms "upper," "lower," "inner," and "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or the orientations or positional relationships in which the product of this application is typically placed when in use. These terms are intended solely to facilitate the description of this application and simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0067] It should also be noted that, in the description of this application, unless otherwise expressly specified or limited, the terms "disposed," "installed," and "connected" should be understood broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0068] First embodiment

[0069] Please refer to Figures 1 to 4. This embodiment provides a solar cell string 1, including: a bus bar 2, an interconnecting bar 3 and a cell 4; a plurality of cell slices 4 are arranged in sequence along a preset direction, and adjacent cell slices 4 are connected by the interconnecting bar 3; the bus bar 2 is provided on the cell slice 4 and extends along the arrangement direction of the cell slice 4; along the extension direction of the bus bar 2, the bus bar 2 includes a plurality of welding portions 5 and a non-welding portion 6 connecting two adjacent welding portions 5, the welding portion 5 is welded to at least one interconnecting bar 3, and the non-welding portion 6 is spaced apart from at least one interconnecting bar 3.

[0070] In this embodiment, the bus bar 2 is arranged on the battery cell 4 and is directly welded to the interconnection bar 3 through the welding portion 5, which can ensure the melting of the tin layer and the contact welding effect. The non-welding portion 6 is spaced apart from at least one interconnection bar 3 to release the stress generated by the thermal expansion and contraction of the bus bar 2 and the interconnection bar 3 during the welding process of the bus bar 2, and prevent the bus bar 2 from shrinking after welding and causing the welding strip on the back of the battery cell 4 to be pulled and offset. Compared with the existing traditional shingled solar cell module in which the bus bar 2 is directly contacted and welded with the pad point on the back of the battery cell 4, this arrangement has a lower fragmentation rate, a larger process window and does not require additional Auxiliary welding materials such as tin paste or flux are added, and the amount of back silver is significantly reduced, so the battery efficiency is improved. Even if the battery cell 4 is thin, the hidden cracks of the battery cell 4 are also low. Compared with the existing half-cell welding method, this setting method does not require a 10mm to 20mm bus bar 2 and interconnection bar 3 welding area in the middle of the component. During welding, the head and tail battery strings of the component do not need to be misaligned, and the welding of the interconnection bars 3 on both sides does not interfere with each other, which improves the efficiency of the component. At the same time, it can release the pulling force of the film flow on the battery string during the lamination process, reduce the risk of hidden cracks and fragments of the battery string, and improve the overall aesthetics.

[0071] In this embodiment, busbar 2 is directly welded to interconnecting bar 3 connecting cell 4, rather than directly contacting and welding busbar 2 to the back pad of cell 4 in conventional shingled solar cell modules. This can address process defects caused by welding the back pad of cell 4 to busbar 2 in conventional shingled solar cell modules, such as a 0.02% to 0.05% increase in fragmentation rate, a narrow process window, and the need for additional auxiliary welding materials such as solder paste or flux. It can also address the impact of the 10-20mm central welding area connecting busbar 2 and interconnecting bar 3 in existing half-cell modules on welding quality, module efficiency, and post-lamination appearance. It can also relieve the pulling force of the film flow on the cell string during the lamination process, reducing hidden cracks in the cell string.

[0072] In an optional technical solution of this embodiment, the non-welded portion 6 is arched relative to the two adjacent welded portions 5 .

[0073] In this embodiment, along the extension direction of the busbar 2, the welding portion 5 is planar and the non-welding portion 6 is arched, so that the welding portion 5 can be welded to the interconnection bar 3 and the non-welding portion 6 can cross the interconnection bar 3. The structure is simple and the production is convenient.

[0074] This embodiment is not limited to this. The welding portion 5 and the non-welding portion 6 may both be planar, and the thickness of the welding portion 5 is greater than the thickness of the non-welding portion 6, that is, the welding portion 5 can contact and weld with the interconnection bar 3, and there is a gap between the non-welding portion 6 and the interconnection bar 3.

[0075] In the optional technical solution of this embodiment, the arched shape of the non-welded portion 6 is an arc, a triangle, a trapezoid or a square. However, the non-welded portion 6 can also be any other shape that meets the requirements.

[0076] Preferably, the busbar 2 is an integrally formed structure, which is stable and easy to manufacture. The flat welding portion 5 ensures the tin layer melts and contacts the soldering process, while the arched non-welding portion 6 relieves the stress caused by thermal expansion and contraction between the busbar 2 and the interconnecting strip 3 during the welding process, preventing the shrinkage of the busbar 2 after welding, which may cause the solder strip on the back of the cell 4 to be pulled and offset.

[0077] In an optional technical solution of this embodiment, the connection between the welding portion 5 and the non-welding portion 6 is set to be a chamfer 7, a right angle or a rounded corner 8.

[0078] In this embodiment, the arching transition between the welding portion 5 and the non-welding portion 6 is a chamfer 7 , a right angle or a rounded corner 8 , so that the busbar 2 is arched as a whole to form the non-welding portion 6 with better effect.

[0079] In the optional technical solution of this embodiment, the height of the non-welded portion 6 is h, and 0<h≤2mm. The structure is simple and easy to manufacture, and does not occupy too much space.

[0080] Specifically, the number of arches, arch height and arch shape of the busbar 2 are optimally designed according to the number of main grids of different battery cells 4 and the different number of welding points (i.e., the welding points between the welding parts 5 and the interconnecting bars 3). The welding parts 5 between the busbar 2 and the interconnecting bars 3 on the back of the battery cell 4 are divided into contact designs, and the non-welding parts 6 are divided into arch designs. The preferred number of arches is 2 to 19, but the specific number depends on the needs.

[0081] In an optional technical solution of this embodiment, the battery cell 4 has a front side and a back side, and the bus bar 2 is located on the back side of the battery cell 4 and is welded to the back side of the interconnection bar 3. This does not affect the use of the front side.

[0082] In an optional technical solution of this embodiment, the thickness of the busbar 2 is 0.05 mm-0.15 mm.

[0083] In an optional technical solution of this embodiment, the width of the busbar 2 is 5 mm-15 mm.

[0084] In this embodiment, the busbar 2 is designed to be thinner and wider, which can solve the problem of hidden cracks in the welding of the battery cell 4 and improve the battery's carrying capacity.

[0085] In an optional technical solution of this embodiment, the battery cell 4 is formed by cutting a 182 mm silicon wafer into two or three pieces; or, the battery cell 4 is formed by cutting a 210 mm silicon wafer into two or three pieces.

[0086] In this embodiment, the battery cell 4 uses large-size silicon wafers such as 182 / 210, with a design of cutting in two or cutting in three, and a main grid line number of 10 to 20BB, which is compatible with Perc, N-type, HJT and other process batteries.

[0087] Second embodiment

[0088] Please refer to FIG4 . This embodiment provides a solar cell assembly including the solar cell string 1 . Therefore, the technical advantages and effects achieved by the solar cell assembly include the technical advantages and effects achieved by the solar cell string 1 , which will not be described in detail here.

[0089] Specifically, the solar cell assembly includes three bypass diodes 9 and six solar cell strings 1 arranged in parallel;

[0090] The three solar cell strings 1 on the left of the six solar cell strings 1 are connected in parallel to form a first group, the three solar cell strings 1 on the right are connected in parallel to form a second group, and the first group and the second group are connected in series;

[0091] Three bypass diodes 9 are connected in parallel via the bus bar 2 .

[0092] In this embodiment, the solar cell assembly is designed as a six-string assembly, and the circuit is designed as follows: three strings of solar cell strings 1 on the left are connected in parallel, three strings of solar cell strings 1 on the right are connected in parallel, and three strings of solar cell strings 1 on the left and right are connected in series. At the same time, by optimizing the interconnection strips 3 on the back of the battery cell 4 and connecting them with the corresponding bus bars 2 of the bypass diodes 9, the electrical connection design of the three bypass diodes 9 in parallel is realized, which has a simple structure and high conductive efficiency.

[0093] Third embodiment

[0094] Please refer to Figures 5, 6, 7 and 8. This embodiment provides a solar cell string 100, which includes at least two cells 110 arranged in sequence. The two adjacent cells 110 are connected by a plurality of interconnecting bars 120. A bus bar 130 is provided on all the interconnecting bars 120 connected to at least one cell 110. The bus bar 130 includes a plurality of fixed sites 131 spaced apart along the length direction and a non-fixed segment connecting two adjacent fixed sites 131. The fixed site 131 is fixedly connected to the interconnecting bar 120 below it, and at least a portion of the non-fixed segments are mounted on the interconnecting bar 120. The non-fixed segments are not fixedly connected to the interconnecting bar 120 below it, and the non-fixed segments are in contact with at least a portion of the interconnecting bars 120 below it.

[0095] In the embodiment of the present application, the busbar 130 in the solar cell string 100 is arranged on the interconnection bar 120 on a certain cell. Under normal circumstances, the solar cell string 100 is provided with one busbar 130. Of course, two or more busbars 130 can also be provided as needed. The cell 110 has a front and a back. The front and back refer to the two opposite surfaces of the cell 110. The front refers to the surface facing the sun during actual use, and the back refers to the surface facing away from the sun. As an embodiment, the connection between two adjacent cells 110 through the interconnection bar 120 means that the front (positive pole) of one cell 110 is connected to the back (negative pole) of the adjacent cell 110 through the interconnection bar 120. The connection method of the solar cell string 100 is that the front of the first cell 110 is connected to the back of the second cell 110 through the interconnection bar 120, and the front of the second cell 110 is connected to the back of the third cell 110 through the interconnection bar 120. As an embodiment, the bus bar 130 is located on the back side of the middle battery cell 110 and is welded to the back side of the interconnection bar 120 located on the back side. Figures 5, 6 and 7 show the connection status of the back side of the battery cell 110. The dots in Figure 5 represent battery cells not shown in the figure.

[0096] In the embodiment of the present application, the fixed position 131 of the bus bar 130 refers to the position fixed to the corresponding interconnection bar 120 in a fixed manner, and the fixed position 131 and the interconnection bar 120 will not be separated during the conventional process and use; the non-fixed sections of the bus bar 130 are divided into two types, one is the first non-fixed section 132, which has the interconnection bar 120 below it (laid on the interconnection bar 120), this non-fixed section is not fixed by any fixing method or is not welded, and the non-fixed section and the corresponding interconnection bar 120 can be separated; the other is the second non-fixed section, which has no interconnection bar 120 below it, and this non-fixed section will definitely not be connected or contacted with the interconnection bar 120.

[0097] Exemplarily, the fixing methods include welding and bonding. The welding method is to weld the bus bar 130 and the interconnection bar 120 together through mainstream welding methods such as infrared heating, electromagnetic heating or hot air welding; the bonding method is to use glue to bond, such as conductive glue, insulating glue, thermosetting glue and UV glue. Different glues have different curing conditions. Conductive glue, insulating glue and thermosetting glue need to be heated or cured during the lamination process, and UV glue needs to be cured by ultraviolet light or heating.

[0098] The non-fixed section may not be fixed, or a low-temperature bus bar 130 or a low-temperature interconnect bar 120 with a lower melting point (such as SnPbBi, SnBiAg and other alloys) may be used. The lamination process will cause melting and solidification, and after lamination, the bus bar 130 and the interconnect bar 120 will form a good physical contact.

[0099] In some embodiments of the present application, the battery cell 110 may be formed by cutting a 182 mm silicon wafer into two or three pieces; in some other embodiments of the present application, the battery cell 110 may also be formed by cutting a 210 mm silicon wafer into two or three pieces.

[0100] In some embodiments of the present application, the battery cells 110 are arranged side by side (without overlapping) along the arrangement direction, and the electrical connection between the battery cells 110 is achieved through the interconnection bars 120 .

[0101] In some embodiments of the present application, the material of the busbar 130 is tinned copper strip or other conductive materials, the thickness of the busbar 130 is 0.05 mm-0.15 mm, and the width of the busbar 130 is 5 mm-15 mm;

[0102] The interconnection bar 120 is made of tinned copper strip or other conductive materials, and the diameter of the interconnection bar 120 is 0.15-0.3 mm.

[0103] In some embodiments of the present application, busbars 130 are located on the battery cells. Each fixed location 131 is fixedly connected to the corresponding location on the battery cell 110 via the interconnecting bar 120 below it. The number of fixed locations 131 is typically 4 to 20, thereby ensuring the current carrying capacity and connection strength of the busbars 130 and the interconnecting bars 120. In some embodiments of the present application, the number of interconnecting bars 120 installed below the non-fixed segments of the interconnecting bar 120 is 1 to 3.

[0104] In this embodiment, each fixed point 131 is fixedly connected to an interconnecting bar 120 below it, specifically through welding. The interconnecting bars 120 corresponding to the fixed points 131 are discontinuous and lack a second non-fixed segment. Two interconnecting bars 120 are located below each non-fixed segment (first non-fixed segment 132) of the interconnecting bar 120. Each non-fixed segment (first non-fixed segment 132) of the interconnecting bar 120 is in contact with all interconnecting bars 120 below it. Overall, the busbar 130 is straight, with the fixed points 131 of the busbar 130 fixedly connected to the interconnecting bar 120, and the non-fixed segments in contact with the interconnecting bar 120. In other embodiments, the number of interconnecting bars 120 under each non-fixed segment (first non-fixed segment 132) is three or more; in other embodiments, each non-fixed segment (first non-fixed segment 132) contacts some interconnecting bars 120 under it, but does not contact other interconnecting bars 120, for example, it is at a distance from the interconnecting bars 120. In other embodiments, the bus bars 130 may be curved on the surface of the cell, which can also reduce stress on the bus bars 130.

[0105] Fourth embodiment

[0106] Referring to Figure 9 , this embodiment provides a solar cell string that differs from the third embodiment in that at least some of the non-fixed segments located between adjacent interconnecting bars 120 are recessed toward the cell 110, and the connection between these recessed segments and other segments is configured as a chamfer, right angle, or rounded corner. In this embodiment, the portion of each non-fixed segment (first non-fixed segment 132) located between adjacent interconnecting bars 120 is recessed toward the cell 110.

[0107] In other embodiments, the busbar 130 with excess length may be folded after lamination. Specifically, the portion of the non-fixed segment in contact with the interconnection bar 120 may also have a folded portion, which is no higher than the surface of the busbar 130 .

[0108] Fifth embodiment

[0109] Referring to FIG. 10 , this embodiment provides a solar cell string that differs from the third embodiment in that: some adjacent interconnecting bars 120 are connected to fixed locations 131, and some adjacent interconnecting bars 120 are provided with non-fixed segments that contact the interconnecting bars 120 below them. In this embodiment, a bus bar 130 is fixed to two consecutive interconnecting bars 120 to form two fixed locations 131. The non-fixed segment between the two fixed locations 131 is a second non-fixed segment 133, which is straight. The bus bar 130 is then provided on two consecutive interconnecting bars 120 to form a loop unit. Subsequent bus bars 130 are repeatedly provided in this loop unit. The non-fixed segment provided on the interconnecting bar 120 is a first non-fixed segment 132, which has two interconnecting bars 120 below it. The portion of this non-fixed segment located between adjacent interconnecting bars 120 is recessed toward the solar cell 110.

[0110] Sixth embodiment

[0111] Referring to Figure 11, this embodiment provides a solar cell assembly comprising several solar cell strings according to the third embodiment, arranged in parallel. The busbars 130 of the solar cell strings are sequentially connected. The non-fixed sections of the busbars 130 are areas not welded or secured. The dots in Figure 11 represent cells (not shown). In this embodiment, the same busbar 130 connects all solar cell strings. In other embodiments, busbars 130 may be provided independently for each solar cell string and then connected together.

[0112] In summary, the solar cell strings and solar cell modules of the embodiments of the present application do not require PAD points to be set on the surface, nor do they require the addition of auxiliary welding materials, which can reduce the material consumption of single-cell cells and improve battery efficiency; and the busbar connection effect is good, reducing the occurrence of adverse phenomena; it can also reduce the pulling and twisting caused by slight displacement of the cell string, thereby improving the overall aesthetics of the module.

[0113] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application. Industrial Applicability

[0114] The present disclosure provides a solar cell string and a solar cell module, wherein a bus bar is connected to an interconnection bar via a welding portion or a fixed position, and a non-welded portion of the bus bar is spaced from the interconnection bar, or a non-fixed section is in contact with the interconnection bar. This not only ensures the connection effect but also reduces pulling and twisting phenomena, thereby having industrial applicability.

Claims

1. A solar cell string, comprising: busbar ribbons, interconnectors, and solar cells;a plurality of solar cells are arranged sequentially along a preset direction, and the adjacent solar cells are connected through the interconnectors;the busbar ribbons are provided on the solar cells and extend along an arrangement direction of the solar cells; andalong the extension direction of the busbar ribbons, the busbar ribbons comprise a plurality of soldering parts and non-soldering parts connecting the two adjacent soldering parts, wherein the soldering parts are welded with at least one of the interconnectors, and the non-soldering parts are arranged with spacing from at least one of the interconnectors.

2. The solar cell string according to claim 1, wherein the non-soldering parts are arched relative to the two adjacent soldering parts.

3. The solar cell string according to claim 2, wherein an arched shape of the non-soldering parts is arc-shaped, triangular, trapezoidal, or rectangular.

4. The solar cell string according to claim 2 or 3, wherein a joint between the soldering parts and the non-soldering parts is arranged as chamfered, right-angled, or rounded.

5. The solar cell string according to any one of claims 2 to 4, wherein an arching height of the non-soldering parts is h, and 0 < h < 2mm.

6. The solar cell string according to any one of claims 1 to 5, wherein the solar cells have a front surface and a rear surface, and the busbar ribbons are located on the rear surface of the solar cells and welded with the rear surface of the interconnectors.

7. The solar cell string according to any one of claims 1 to 6, wherein a thickness of the busbar ribbons is 0.05mm-0.15mm.

8. The solar cell string according to any one of claims 1 to 7, wherein a width of the busbar ribbons is 5mm-15mm.

9. The solar cell string according to any one of claims 1 to 8, wherein the solar cells are formed by dividing a 182mm silicon wafer into two or three slices; orthe solar cells are formed by dividing a 210mm silicon wafer into two or three slices.

10. A photovoltaic cell module, comprising three bypass diodes and six solar cell strings according to any one of claims 1-9 arrayed parallelly;the six solar cell strings comprise three solar cell strings on a left side connected in parallel to form a first group, and three solar cell strings on a right side connected in parallel to form a second group, wherein the first group and the second group are connected in series; andthe three bypass diodes are connected in parallel through the busbar ribbons.

11. A solar cell string, comprising: at least two solar cells arranged sequentially, wherein two adjacent solar cells are respectively connected therebetween through a plurality of interconnectors, and one of the busbar ribbons is provided on all the interconnectors connected to at least one of the solar cells; andthe busbar ribbons comprise a plurality of fixed points arranged at intervals along a length direction and non-fixed sections connecting the two adjacent fixed points, wherein the fixed points are fixedly connected to the interconnectors thereunder; at least some of the non-fixed sections are laid on the interconnectors; the non-fixed sections are not fixedly connected to the interconnectors thereunder; and the non-fixed sections are in contact with at least some of the interconnectors thereunder.

12. The solar cell string according to claim 11, wherein the busbar ribbons are located on the cell, and each of the fixed points is fixedly connected to a corresponding position of the solar cells through the interconnectors thereunder.

13. The solar cell string according to claim 11 or 12, wherein each of the fixed point is fixedly connected to one of the interconnectors thereunder.

14. The solar cell string according to any one of claims 11 to 13, wherein a number of interconnectors below the non-fixed sections laid on the interconnectors is 1-3.

15. The solar cell string according to any one of claims 11 to 14, wherein the non-fixed sections laid on the interconnectors are in contact with all the interconnectors thereunder.

16. The solar cell string according to any one of claims 11 to 15, wherein at least some of the non-fixed sections, located between the adjacent interconnectors, are recessed toward the solar cells.

17. The solar cell string according to any one of claims 11 to 16, wherein a part of the nonfixed sections in contact with the interconnectors has folded sections, and the folded sections do not exceed a surface of the busbar ribbons.

18. The solar cell string according to any one of claims 11 to 17, wherein a material of the busbar ribbons is a tin-coated copper ribbon; a thickness of the busbar ribbons is 0.05~0.15mm; and a width of the busbar ribbons is 5~15mm.

19. The solar cell string according to any one of claims 11 to 18, wherein a material of the interconnectors is a tin-coated copper ribbon, and a diameter of the interconnectors is 0.15~0.3mm.

20. A photovoltaic cell module, comprising a plurality of solar cell strings according to any one of claims 11-19, wherein the busbar ribbons of all the solar cell strings are connected sequentially.

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