Battery string and photovoltaic module

Abstract

According to the battery string and the photovoltaic module, on one hand, the first front bus bar is arranged on the back surface of the first battery piece, so that the front space is not occupied, the effective light receiving area of the photovoltaic module can be effectively improved, and the light efficiency is improved; on the other hand, the first insulating strip is positioned between the first front bus bar and the first back welding strip, so that a short-circuit fault caused by electric contact between the first front bus bar and the first back welding strip can be effectively prevented; furthermore, a low-temperature tin layer is arranged on at least one of the surface of the first lead-out part and the outer wall surface of the first front bus bar, and the hot melting temperature of the low-temperature tin layer is 130-200 DEG C, so that the welding temperature is controlled to be 130-200 DEG C, the first lead-out part and the first front bus bar can be welded and connected together, and alloy is formed at the contact part of the first lead-out part and the first front bus bar; the welding temperature is relatively low, and the first insulating strip cannot be damaged.

Description

Technical Field

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

[0002] The most important performance indicator for photovoltaic (PV) modules is conversion efficiency. Increasing the screen-to-body ratio of PV modules can effectively improve their conversion efficiency. PV modules mainly use a half-cell design. For half-cell PV modules, the busbars, whether located at the head, tail, or middle of the module, are all on the same plane as the solar cells, thus occupying a certain amount of the front-side light-receiving area of ​​the module. For example, in a 210-66 panel, the ratio of the busbar area to the front-side area of ​​the PV module is approximately 1.02%. Therefore, some have proposed placing the busbars on the back of the solar cells to convert the area occupied by the busbars into the effective light-receiving area of ​​the solar cells, thereby increasing the output power of the PV module by 1.02%. In related technologies, PV modules have back-side solder strips. When a busbar connected to the front solder strip (also called a front busbar) is installed on the back of the solar cells, the front busbar connected to the front solder strip will come into contact with the back solder strip, causing a short circuit fault, which makes the assembly of the PV module more difficult. Utility Model Content

[0003] Therefore, it is necessary to overcome the shortcomings of the existing technology and provide a battery string and photovoltaic module that can increase the output power by increasing the effective light-receiving area of ​​the battery cells, while avoiding short-circuit faults and facilitating assembly.

[0004] A battery string includes: at least two battery cells and at least two solder strips, wherein the at least two battery cells are connected in series by the at least two solder strips; the battery cell at the first end is designated as a first battery cell, and the battery cell at the last end is designated as a second battery cell; the solder strip on the front side of the first battery cell is designated as a first front solder strip, and the solder strip on the back side of the first battery cell is designated as a first back solder strip.

[0005] The battery string also includes:

[0006] A first insulating strip is disposed on the back of the first battery cell and located on one edge of the first battery cell opposite to the second battery cell; and

[0007] The first front busbar is disposed on the back of the first battery cell and located on the side edge of the first battery cell opposite to the second battery cell.

[0008] The first insulating strip is located between the first front busbar and the first back solder strip. The first front solder strip has a first lead-out portion, which is folded to the back of the first battery cell and soldered to the first front busbar. At least one of the surface of the first lead-out portion and the outer wall surface of the first front busbar is provided with a low-temperature tin layer, and the hot melt temperature of the low-temperature tin layer is 130°C to 200°C.

[0009] In one embodiment, the low-temperature tin layer is SnPbBi or SnBiAg.

[0010] In one embodiment, the battery string further includes a first back busbar, which is disposed on the back of the second battery cell and located on one side edge of the second battery cell away from the first battery cell. The solder strip on the back of the second battery cell is a second back solder strip, which has a second lead-out portion, and the second lead-out portion is welded to the first back busbar.

[0011] In one embodiment, at least one of the surface of the second lead-out portion and the outer wall surface of the first back busbar is provided with a low-temperature tin layer.

[0012] A photovoltaic module, the photovoltaic module comprising the aforementioned battery string.

[0013] In one embodiment, there are two battery strings, which are arranged sequentially along the extension direction of the solder strip, with the second battery cells of the two battery strings close to each other; the battery string also includes a second back busbar, which is disposed on the back of the second battery cell and located on one side edge of the second battery cell away from the first battery cell, the solder strip on the back of the second battery cell is designated as the second back solder strip, the second back solder strip has a second lead-out portion, and the second lead-out portion is welded to the second back busbar; the second back busbars of the two battery strings are connected as one unit.

[0014] A photovoltaic module includes two cell strings, each cell string including at least two solar cells and at least two solder strips, wherein the at least two solar cells are connected in series via the at least two solder strips; the two cell strings are arranged along the extension direction of the solder strips.

[0015] In each battery string, the battery cell at the first end is designated as the first battery cell, and the battery cell at the last end is designated as the second battery cell; the solder strip on the front side of the first battery cell is designated as the first front solder strip, and the solder strip on the back side of the first battery cell is designated as the first back solder strip, and the first front solder strip is provided with a first lead-out portion; the first battery cells of two battery strings are arranged close to each other, and the two first battery cells are provided with a gap.

[0016] The photovoltaic module also includes:

[0017] A second insulating strip is disposed on the back of the first battery cell and located on one edge of the first battery cell opposite to the second battery cell; and

[0018] The second front busbar is disposed on the back of the first battery cell and located on at least one of the first battery cells, away from one side edge of the second battery cell. The width of the second front busbar is greater than the distance between the two second battery cells.

[0019] The second insulating strip is located between the second front busbar and the first back solder strip. The first lead-out portion extends to the back of the first battery cell and is soldered to the second front busbar. At least one of the surface of the first lead-out portion and the outer wall surface of the second front busbar is provided with a low-temperature tin layer, and the hot melt temperature of the low-temperature tin layer is 130°C to 200°C.

[0020] In one embodiment, there are two second insulating strips, each arranged on the back of one of the two first battery cells; there is one second front busbar, located on the back edge of one of the two first battery cells that are close to each other; the first lead-out portion is folded to the back of its corresponding first battery cell and welded to the second front busbar, or the first lead-out portion extends to the back of another first battery cell adjacent to its corresponding first battery cell and is welded to the second front busbar.

[0021] In one embodiment, the second insulating strip is provided as one, and the second front busbar is provided as one. The second insulating strip and the second front busbar are both provided on the back edge of one of the first battery cells. The first lead-out portion of one of the first battery cells is folded to the second front busbar, and the first lead-out portion of the other first battery cell extends to the second front busbar.

[0022] In one embodiment, each of the first leads of the same first battery cell is located on the same side of the second front busbar.

[0023] The aforementioned battery string and photovoltaic module, on the one hand, by placing the first front busbar on the back of the first battery cell, does not occupy the front space, thus effectively increasing the effective light-receiving area of ​​the photovoltaic module and thereby improving light efficiency; on the other hand, the first insulating strip is located between the first front busbar and the first back solder strip, effectively preventing short-circuit faults caused by electrical contact between the first front busbar and the first back solder strip; in addition, since at least one of the surface of the first lead-out portion and the outer wall surface of the first front busbar is provided with a low-temperature tin layer, the hot melting temperature of the low-temperature tin layer is 130°C to 200°C, thus controlling the welding temperature at 130°C to 200°C, the first lead-out portion and the first front busbar can be welded together and an alloy can be formed at the contact point between the two, and the relatively low welding temperature will not cause damage to the first insulating strip. Attached Figure Description

[0024] Figure 1 This is a structural diagram of a battery string according to an embodiment of this application.

[0025] Figure 2 This is a structural diagram of a battery string according to another embodiment of this application.

[0026] Figure 3 This is a structural diagram of a photovoltaic module according to an embodiment of this application.

[0027] Figure 4 for Figure 3 Enlarged structural diagram at point A.

[0028] Figure 5 This is a structural diagram of a photovoltaic module according to an embodiment of this application.

[0029] Figure 6 for Figure 5 Enlarged structural diagram at point B.

[0030] Figure 7 This is a structural diagram of a photovoltaic module according to an embodiment of this application.

[0031] Figure 8 for Figure 7 Enlarged structural diagram at point C.

[0032] 10. Battery string; 11. First battery cell; 111. First lead-out portion; 112. First back solder strip; 12. Second battery cell; 121. Second back solder strip; 1211. Second lead-out portion; 13. First insulating strip; 14. First front busbar; 15. First back busbar; 16. Second back busbar; 20. Second insulating strip; 30. Second front busbar. Detailed Implementation

[0033] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0034] It should be noted that, for ease of description, distinction, and understanding of the solder strips and busbars in this application, in this embodiment, the solder strip located on the front side of the battery cell is called the front solder strip, the solder strip located on the back side of the battery cell is called the back solder strip, the busbar electrically connected to the front solder strip is called the front busbar, and the busbar connected to the back solder strip is called the back busbar. It should be noted that the term "front" in "front busbar" is only used to distinguish whether it is connected to the front solder strip or the back solder strip, and should not be construed as limiting its specific location on the front or back side of the battery cell; similarly, the term "back" in "back busbar" is only used to distinguish whether it is connected to the front solder strip or the back solder strip, and should not be construed as limiting its specific location on the front or back side of the battery cell.

[0035] As mentioned in the background art, in the prior art, when the front busbar is placed on the back of the battery cell, it will come into contact with the back solder strip, causing a short circuit. The inventors have discovered that the reason for this problem is that although an insulating strip is provided on the back of the battery cell and placed between the back solder strip and the front busbar to insulate and isolate the front busbar from the back solder strip, the high temperature generated during the process of the front solder strip being folded to the back of the battery cell and welded to the front busbar will cause the insulating strip to melt and fail, which will then cause the back solder strip to come into contact with the front busbar, resulting in a short circuit.

[0036] It should be noted that, in order to clearly demonstrate and understand the structural scheme of this application, the present application's... Figures 1 to 8 Each battery cell is shown with its back side facing out, that is... Figures 1 to 8 The side of each solar cell that can be observed is the back of the solar cell, and the side that cannot be observed is the front of the solar cell.

[0037] See Figure 1 , Figure 1This diagram illustrates the structure of a battery string 10 according to an embodiment of this application. The battery string 10 provided in this embodiment includes at least two battery cells and at least two solder strips, with the at least two battery cells connected in series via the at least two solder strips. The battery cell at the first end is designated as a first battery cell 11, and the battery cell at the last end is designated as a second battery cell 12. The solder strip on the front side of the first battery cell 11 is designated as a first front solder strip, and the solder strip on the back side of the first battery cell 11 is designated as a first back solder strip 112.

[0038] The battery string 10 also includes: a first insulating strip 13 and a first front busbar 14.

[0039] The first insulating strip 13 is disposed on the back of the first battery cell 11 and is located on the side edge of the first battery cell 11 away from the second battery cell 12.

[0040] The first front busbar 14 is located on the back of the first battery cell 11 and on one side edge of the first battery cell 11 away from the second battery cell 12.

[0041] The first insulating strip 13 is located between the first front busbar 14 and the first back solder strip 112. The first front solder strip has a first lead-out portion 111, which is folded to the back of the first battery cell 11 and soldered to the first front busbar 14. At least one of the surface of the first lead-out portion 111 and the outer wall surface of the first front busbar 14 is provided with a low-temperature tin layer, the hot melt temperature of which is 130°C to 200°C.

[0042] The aforementioned battery string 10, on the one hand, because the first front busbar 14 is located on the back of the first battery cell 11, it does not occupy the front space, thus effectively increasing the effective light-receiving area of ​​the photovoltaic module and thereby improving the light efficiency; on the other hand, the first insulating strip 13 is located between the first front busbar 14 and the first back solder strip 112, which can effectively prevent the first front busbar 14 and the first back solder strip 112 from making electrical contact and causing a short circuit fault; in addition, since at least one of the surface of the first lead-out portion 111 and the outer wall surface of the first front busbar 14 is provided with a low-temperature tin layer, the hot melting temperature of the low-temperature tin layer is 130°C to 200°C, so the welding temperature is controlled at 130°C to 200°C, the first lead-out portion 111 and the first front busbar 14 can be welded together and an alloy can be formed at the contact point between the two. The welding temperature is relatively low and will not cause damage to the first insulating strip 13.

[0043] Since the melting temperature of the low-temperature tin layer is between 130°C and 200°C, specifically, it can be 130°C, 140°C, 150°C, 170°C, 190°C, or 200°C, etc. This allows the first front busbar 14 to be welded to the first lead-out portion 111 to form an alloy during the lamination process of the photovoltaic module; furthermore, the welding temperature is not so low that it would be incompatible with the lamination process.

[0044] It should be noted that the first lead-out portion 111 refers to the part of the first front solder strip that protrudes from the side edge of the first battery cell 11 away from the second battery cell 12. It is mainly used to electrically connect with the first front busbar 14, so that each first front solder strip is connected in parallel to the first front busbar 14.

[0045] For example, the first front busbar 14 is placed on the first insulating strip 13. Each first lead-out portion 111, after being folded, is arranged, for example, on the side of the first front busbar 14 away from the first insulating strip 13. Of course, they can also be arranged, for example, between the first front busbar 14 and the first insulating strip 13. In this way, since each first lead-out portion 111 is located on the same side of the first front busbar 14, compared to the method of having first lead-out portions 111 on opposite sides of the first front busbar 14, it is beneficial to achieve a stable connection between each first lead-out portion 111 and the first insulating strip 13, and the assembly efficiency is higher.

[0046] It should be noted that the low-temperature tin layer can be disposed on the first lead-out portion 111, or on the first front bus bar 14, or both the first lead-out portion 111 and the first front bus bar 14 can be disposed on the low-temperature tin layer, as long as the first lead-out portion 111 and the first front bus bar 14 can be soldered and fixed.

[0047] For example, a low-temperature tin layer can be provided on the outer wall surface of the first front busbar 14, and there is no need to provide a low-temperature tin layer on the first lead-out portion 111. This can reduce the amount of material used for the low-temperature tin layer and thus reduce costs.

[0048] For example, a low-temperature tin layer is provided on each part of the outer wall of the first front busbar 14, so that a low-temperature tin layer is provided on the first lead-out portion 111; of course, it can also be a partial part of the first front busbar 14, that is, specifically on the first lead-out portion 111.

[0049] Optionally, the low-temperature tin layer in this embodiment can be various alloy materials containing tin and bismuth, such as SnPbBi and SnBiAg. Thus, since the low-temperature tin layer contains not only tin but also bismuth, the melting point can be effectively reduced by flexibly adjusting and controlling the bismuth content, making it suitable for low-temperature welding scenarios and exhibiting the characteristics of low melting point and good fluidity.

[0050] Please see Figure 1 or Figure 2In one embodiment, the battery string 10 further includes a first back busbar 15. The first back busbar 15 is disposed on the back of the second battery cell 12 and located on one edge of the second battery cell 12 opposite to the first battery cell 11. The solder strip on the back of the second battery cell 12 is designated as a second back solder strip 121. The second back solder strip 121 has a second lead-out portion 1211, which is soldered to the first back busbar 15. Thus, by disposing of the first back busbar 15 on the back of the second battery cell 12, it does not occupy front space, effectively increasing the effective light-receiving area of ​​the photovoltaic module and thereby improving light efficiency. Furthermore, after each second lead-out portion 1211 is connected to the first back busbar 15, each second back solder strip 121 is connected in parallel to the first back busbar 15.

[0051] It should be noted that the second lead-out portion 1211 refers to the end of the second back solder strip 121 that is away from the first battery cell 11. Since the first back busbar 15 is located on the back of the second battery cell 12, the second lead-out portion 1211 can be arranged on one side edge of the back of the second battery cell 12, or it can be a part protruding from the side edge of the second battery cell 12 away from the first battery cell 11. It is mainly used for electrical connection with the first back busbar 15, so that each second back solder strip 121 is connected in parallel to the first back busbar 15.

[0052] Please refer to Figure 1 When the second lead-out portion 1211 is arranged on one side edge of the back surface of the second battery cell 12, that is, when the second lead-out portion 1211 does not protrude beyond the outer edge of the second battery cell 12 away from the first battery cell 11, the first back busbar 15 can be stacked and placed on one side edge of the back surface of the second battery cell 12, and the first back busbar 15 can be welded to each of the second leads-out portions 1211. Figure 1 The second lead-out portion 1211 is blocked by the first rear busbar 15; please refer to Figure 2 When the second lead-out portion 1211 protrudes from the outside of the side edge of the second battery cell 12 away from the first battery cell 11, the first back busbar 15 can be stacked and placed on the back side edge of the second battery cell 12, and then the second lead-out portion 1211 can be folded over and placed on the first back busbar 15, and then the first back busbar 15 can be welded to each of the second leads-out portions 1211.

[0053] Optionally, a low-temperature tin layer is provided on at least one of the surface of the second lead-out portion 1211 and the outer wall surface of the first back busbar 15. In this way, the first back busbar 15 and the second lead-out portion 1211 can be welded to form an alloy during the lamination process of the photovoltaic module, thereby improving assembly efficiency; in addition, the welding temperature is not so low that it is incompatible with the lamination process.

[0054] The solder strip on the front side of the second battery cell 12 is designated as the second front solder strip, which is not shown in the figure.

[0055] Please see Figure 3 and Figure 4 In one embodiment, this application also provides a photovoltaic module, which includes the battery string 10 of any of the above embodiments.

[0056] The aforementioned photovoltaic module, on the one hand, by placing the first front busbar 14 on the back of the first cell 11, does not occupy the front space, thus effectively increasing the effective light-receiving area of ​​the photovoltaic module and thereby improving light efficiency; on the other hand, the first insulating strip 13 is located between the first front busbar 14 and the first back solder strip 112, effectively preventing short circuit faults caused by electrical contact between the first front busbar 14 and the first back solder strip 112; in addition, since at least one of the surface of the first lead-out portion 111 and the outer wall surface of the first front busbar 14 is provided with a low-temperature tin layer, the hot melting temperature of the low-temperature tin layer is 130°C to 200°C, thus controlling the welding temperature to 130°C to 200°C, the first lead-out portion 111 and the first front busbar 14 can be welded together and an alloy can be formed at the contact point between the two, and the relatively low welding temperature will not cause damage to the first insulating strip 13.

[0057] Please see Figure 3 and Figure 4 For example, there are two battery strings 10, arranged sequentially along the extension direction of the solder strips, with the second solar cells 12 of the two battery strings 10 close to each other. Each battery string 10 also includes a second back busbar 16, which is located on the back of the second solar cell 12 and on one edge of the second solar cell 12 away from the first solar cell 11. The solder strip on the back of the second solar cell 12 is designated as a second back solder strip 121, which has a second lead-out portion 1211. The second lead-out portion 1211 is welded to the second back busbar 16; the second back busbars 16 of the two battery strings 10 are integrated. Thus, by placing the second back busbar 16 on the back of the second solar cell 12, it does not occupy front-side space, effectively increasing the effective light-receiving area of ​​the photovoltaic module and thus improving light efficiency. Furthermore, after each second lead-out portion 1211 is connected to the second back busbar 16, each second back solder strip 121 is connected in parallel to the second back busbar 16. In addition, since the second rear busbar 16 of the two battery strings 10 are connected as one unit, the two battery strings 10 can be connected in parallel.

[0058] Based on the aforementioned embodiment, a gap is provided between the second cells 12 of the two battery strings 10, and the gap between the two second cells 12 is smaller than the width of the second back busbar 16. Thus, by placing the second back busbar 16 on the back of the second cells 12, the gap between the two battery strings 10 is minimized, which helps to increase the effective light-receiving area of ​​the cells, thereby increasing the output power of the photovoltaic module.

[0059] Based on the aforementioned embodiments, in order to improve assembly efficiency, at least one of the surface of the second lead-out portion 1211 and the outer wall surface of the second back busbar 16 is provided with a low-temperature tin layer.

[0060] Please see Figures 5 to 8 In another embodiment, this application also provides a photovoltaic module, which includes two cell strings 10. Each cell string 10 includes at least two solar cells and at least two solder strips, and the at least two solar cells are connected in series via the at least two solder strips. The two cell strings 10 are arranged along the extension direction of the solder strips.

[0061] In each battery string 10, the first battery cell is designated as a first battery cell 11, and the last battery cell is designated as a second battery cell 12. The solder strip on the front side of the first battery cell 11 is designated as a first front solder strip, and the solder strip on the back side of the first battery cell 11 is designated as a first back solder strip 112. The first front solder strip has a first lead-out portion 111. The first battery cells 11 of the two battery strings 10 are arranged close to each other, and the two first battery cells 11 are spaced apart.

[0062] In addition, the photovoltaic module also includes a second insulating strip 20 and a second front busbar 30.

[0063] The second insulating strip 20 is disposed on the back of the first battery cell 11 and is located on the first battery cell 11 at one side edge away from the second battery cell 12. The second front busbar 30 is disposed on the back of the first battery cell 11 and is located on at least one first battery cell 11 at one side edge away from the second battery cell 12, and the width of the second front busbar 30 is greater than the distance between the two second battery cells 12.

[0064] The second insulating strip 20 is located between the second front busbar 30 and the first back solder strip 112. The first lead-out portion 111 extends to the back of the first battery cell 11 and is soldered to the second front busbar 30. At least one of the surface of the first lead-out portion 111 and the outer wall surface of the second front busbar 30 is provided with a low-temperature tin layer, and the hot melting temperature of the low-temperature tin layer is 130°C to 200°C.

[0065] The aforementioned photovoltaic module, on the one hand, because the second front busbar 30 is located on the back of the first cell 11 and the width of the second front busbar 30 is greater than the distance between the two first cells 11, it does not occupy the front space and can effectively increase the effective light-receiving area of ​​the photovoltaic module, thereby improving the light efficiency; on the other hand, the second insulating strip 20 is located between the second front busbar 30 and the first back solder strip 112, which can effectively prevent the second front busbar 30 from making electrical contact with the first back solder strip 112 and causing a short circuit fault; in addition, since at least one of the surface of the first lead-out portion 111 and the outer wall surface of the second front busbar 30 is provided with a low-temperature tin layer, and the hot melting temperature of the low-temperature tin layer is 130°C to 200°C, the welding temperature is controlled at 130°C to 200°C, so that the first lead-out portion 111 and the second front busbar 30 can be welded together and an alloy can be formed at the contact point between the two. The welding temperature is relatively low and will not cause damage to the second insulating strip 20.

[0066] The second front busbar 30 is a busbar positioned between the two battery strings 10. When the two first battery cells 11 are arranged, due to space limitations, the second front busbar 30 cannot be manufactured by first welding it to each of the first leads 111 and then folding it to the back of the first battery cells 11. Therefore, in this application, the first leads 111 can be extended to the back of the first battery cells 11, for example, by folding them over, and then the second front busbar 30 located on the back of the first battery cells 11 can be welded to the first leads 111. This facilitates assembly and improves assembly efficiency.

[0067] During the assembly process, before extending the first lead-out portion 111 to the back of the first battery cell 11, a second insulating strip 20 is placed under the first front solder strip. The second insulating strip 20 can completely cover the first lead-out portion 111 and the second front busbar 30, so that the first lead-out portion 111 and the second front busbar 30 are insulated from the first front solder strip, preventing electrical contact and short circuit faults.

[0068] Please see Figure 5 and Figure 6For example, two second insulating strips 20 are provided, and the two second insulating strips 20 are respectively arranged on the back of the two first battery cells 11. One second front busbar 30 is provided, and the second front busbar 30 is located on the back edge of the two first battery cells 11 at the ends that are close to each other. That is, the width of the second front busbar 30 is relatively large. The second front busbar 30 has two areas that can respectively cover the back edge of the two first battery cells 11, thereby satisfying the welding connection with the first lead 111. For each first battery cell 11, the first lead 111 can be folded to the back of its corresponding first battery cell 11 and welded to the second front busbar 30. As shown in the figure, the first lead 111 of each first battery cell 11 is, for example, folded 180° and extended to the back of its corresponding first battery cell 11.

[0069] Of course, unlike the 180° folding method of each first lead-out portion 111 in the aforementioned embodiments, optionally, each first lead-out portion 111 may extend to the back of another first battery cell 11 adjacent to its corresponding first battery cell 11 and be welded to the second front busbar 30. In this case, the first front solder strip is, for example, arranged in a Z-shape.

[0070] Based on the aforementioned embodiment, in order to prevent the first leads 111 of the two first battery cells 11 from interfering with each other, the first leads 111 of the two first battery cells 11 are staggered relative to each other along the length direction of the second front busbar 30. In this way, all the first leads 111 can be arranged sequentially on one side of the second front busbar 30, thereby ensuring a good welding effect between each first lead 111 and the second front busbar 30, which helps to prevent cold solder joint defects.

[0071] Please see Figure 7 and Figure 8 In one embodiment, a second insulating strip 20 and a second front busbar 30 are provided. Both the second insulating strip 20 and the second front busbar 30 are disposed on the back edge of one of the first battery cells 11. The first lead-out portion 111 of one of the first battery cells 11 is folded to the second front busbar 30, and the first lead-out portion 111 of the other first battery cell 11 extends to the second front busbar 30. In this way, the width of the second insulating strip 20 and the second front busbar 30 is reduced, thereby reducing material usage and lowering costs.

[0072] Please see Figures 5 to 8Based on any of the aforementioned embodiments, each first lead-out portion 111 of the same first battery cell 11 is located on the same side of the second front busbar 30. In this way, when each first lead-out portion 111 and the second front busbar 30 are welded together by means of, for example, lamination, the forces on each part of the second front busbar 30 along its length are more even, which helps to ensure the welding effect and prevent the occurrence of incomplete welding defects.

[0073] More specifically, all the first outlets 111 are located on the same side of the second front busbar 30.

[0074] Based on any of the aforementioned embodiments, for each battery string 10, a first back busbar 15 may also be provided on the back edge of the second battery cell 12. The specific arrangement can be referred to the aforementioned embodiments, and will not be repeated here.

[0075] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0076] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0077] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0078] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0079] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0080] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0081] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery string (10), comprising: At least two battery cells and at least two solder strips, the at least two battery cells are connected in series by at least two solder strips; the battery cell at the first end is designated as the first battery cell (11), and the battery cell at the last end is designated as the second battery cell (12); the solder strip on the front side of the first battery cell (11) is designated as the first front solder strip, and the solder strip on the back side of the first battery cell (11) is designated as the first back solder strip (112); The battery string (10) is characterized in that it further includes: A first insulating strip (13) is disposed on the back of the first battery cell (11) and located on the side edge of the first battery cell (11) opposite to the second battery cell (12); and The first front busbar (14) is disposed on the back of the first battery cell (11) and located on the side edge of the first battery cell (11) opposite to the second battery cell (12); The first insulating strip (13) is located between the first front busbar (14) and the first back solder strip (112). The first front solder strip is provided with a first lead-out portion (111). The first lead-out portion (111) is folded to the back of the first battery cell (11) and soldered to the first front busbar (14). At least one of the surface of the first lead-out portion (111) and the outer wall surface of the first front busbar (14) is provided with a low-temperature tin layer. The hot melt temperature of the low-temperature tin layer is 130°C to 200°C.

2. The battery string (10) according to claim 1, characterized in that, The low-temperature tin layer is SnPbBi or SnBiAg.

3. The battery string (10) according to claim 1, characterized in that, The battery string (10) further includes a first back busbar (15), which is disposed on the back of the second battery cell (12) and located on the side edge of the second battery cell (12) away from the first battery cell (11). The solder strip on the back of the second battery cell (12) is a second back solder strip (121), which is provided with a second lead-out portion (1211) and is welded to the first back busbar (15).

4. The battery string (10) according to claim 3, characterized in that, At least one of the surface of the second lead-out portion (1211) and the outer wall surface of the first back busbar (15) is provided with a low-temperature tin layer.

5. A photovoltaic module, characterized in that, The photovoltaic module includes the battery string (10) as described in claim 1.

6. The photovoltaic module according to claim 5, characterized in that, There are two battery strings (10), and the two battery strings (10) are arranged sequentially along the extension direction of the welding strip. The second battery cells (12) of the two battery strings (10) are close to each other. The battery string (10) also includes a second back busbar (16). The second back busbar (16) is disposed on the back of the second battery cell (12) and located on the side edge of the second battery cell (12) away from the first battery cell (11). The welding strip on the back of the second battery cell (12) is a second back welding strip (121). The second back welding strip (121) is provided with a second lead-out portion (1211). The second lead-out portion (1211) is welded to the second back busbar (16). The second back busbars (16) of the two battery strings (10) are connected as one unit.

7. A photovoltaic module, characterized in that, The photovoltaic module includes two battery strings (10), each battery string (10) including at least two battery cells and at least two solder strips, wherein the at least two battery cells are connected in series by at least two solder strips; the two battery strings (10) are arranged along the extension direction of the solder strips; In each of the battery strings (10), the battery cell at the first end is designated as a first battery cell (11), and the battery cell at the last end is designated as a second battery cell (12); the solder strip on the front side of the first battery cell (11) is designated as a first front solder strip, and the solder strip on the back side of the first battery cell (11) is designated as a first back solder strip (112), and the first front solder strip is provided with a first lead-out portion (111); the first battery cells (11) of the two battery strings (10) are arranged close to each other, and the two first battery cells (11) are provided with a gap; The photovoltaic module also includes: A second insulating strip (20) is disposed on the back of the first battery cell (11) and located on the side edge of the first battery cell (11) opposite to the second battery cell (12); and The second front busbar (30) is disposed on the back of the first battery cell (11) and located on one side edge of at least one first battery cell (11) away from the second battery cell (12). The width of the second front busbar (30) is greater than the distance between the two second battery cells (12). The second insulating strip (20) is located between the second front busbar (30) and the first back solder strip (112). The first lead-out portion (111) extends to the back of the first battery cell (11) and is soldered to the second front busbar (30). At least one of the surface of the first lead-out portion (111) and the outer wall surface of the second front busbar (30) is provided with a low-temperature tin layer, and the hot melt temperature of the low-temperature tin layer is 130°C to 200°C.

8. The photovoltaic module according to claim 7, characterized in that, Two second insulating strips (20) are provided, and the two second insulating strips (20) are respectively arranged on the back of the two first battery cells (11); one second front busbar (30) is provided, and the second front busbar (30) is provided on the back edge of the two first battery cells (11) that are close to each other; the first lead-out portion (111) is folded to the back of the corresponding first battery cell (11) and welded to the second front busbar (30), or the first lead-out portion (111) extends to the back of another first battery cell (11) adjacent to its corresponding first battery cell (11) and is welded to the second front busbar (30).

9. The photovoltaic module according to claim 7, characterized in that, The second insulating strip (20) is provided as one, and the second front busbar (30) is provided as one. The second insulating strip (20) and the second front busbar (30) are both provided on the back edge of one of the first battery cells (11). The first lead-out portion (111) of one of the first battery cells (11) is folded to the second front busbar (30), and the first lead-out portion (111) of the other first battery cell (11) extends to the second front busbar (30).

10. The photovoltaic module according to any one of claims 7 to 9, characterized in that, Each of the first leads (111) of the same first battery cell (11) is located on the same side of the second front busbar (30).

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