Back contact cell string and photovoltaic module

Abstract

The utility model provides a back contact cell string and a photovoltaic assembly. The battery string comprises a plurality of battery pieces, wherein each battery piece is provided with a first edge and a second edge which are orthogonal to each other; the first electrodes extend in the direction parallel to the first edge and are arranged on the back face of the battery piece at equal intervals in the extending direction of the second edge, and each first electrode comprises a plurality of first electrode sections arranged at intervals; wherein the ratio of the length of the first electrode to the length of the first side is greater than 98%, and the ratio of the sum of the first gaps among the plurality of first electrode sections of each first electrode to the length of the first electrode is less than or equal to 6%. The photovoltaic module comprises a plurality of battery strings arranged at intervals.

Description

Technical Field

[0001] At least one embodiment of the utility model relates to the field of photovoltaic technology, and in particular to a battery string and a photovoltaic module. Background Art

[0002] In conventional solar cells, electrodes are usually arranged on the front and back of the cell. The front of the cell is the light-receiving surface, so the electrodes arranged on the front of the cell will inevitably shield part of the light-receiving area of ​​the cell, resulting in a decrease in the energy conversion efficiency of the cell.

[0003] The back contact battery has the characteristic that both the positive electrode and the negative electrode are arranged on the back side of the battery cell, so that the light-receiving surface of the battery cell is not shielded by the metal electrode, thereby effectively improving the energy conversion efficiency of the battery.

[0004] Since the positive electrode and negative electrode of the back contact battery are both arranged on the back of the battery cell, the first electrode needs to be intermittently arranged on different doping areas of the battery cell so that adjacent first electrodes have different polarities. If there are too many gaps formed by adjacent first electrode segments in the same first electrode, the effective collection length of the first electrode will be shorter. However, if the gap is too small, it is easy to cause a short circuit when welding the pad to the first electrode, which is not conducive to current collection. Therefore, how to design the first electrode so that the first electrode has a longer effective collection length and is not easy to short-circuit with the pad has become a technical problem that needs to be solved urgently. Utility Model Content

[0005] To solve at least one of the above and other technical problems in the prior art, the utility model provides a battery string and a photovoltaic module, which can make the first electrode have a longer effective collection length and each first electrode segment have a shorter collection path.

[0006] An embodiment of the utility model provides a back-contact battery, comprising: a plurality of battery cells, each of the battery cells having a first side and a second side that are orthogonal to each other; a plurality of first electrodes extending in a direction parallel to the first side and arranged at equal intervals on the back side of the battery cells along the extension direction of the second side, each of the first electrodes comprising a plurality of first electrode segments arranged at intervals; wherein a ratio of the length of the first electrode to the length of the first side is greater than 98%, and a ratio of the sum of the first gaps between the plurality of first electrode segments of each first electrode to the length of the first electrode is less than or equal to 6%.

[0007] According to an embodiment of the utility model, the back-contact cell string also includes a welding strip, which passes through a first gap formed by two adjacent first electrode segments of the first electrode and is connected to the first electrode segment of the first electrode of the other polarity; wherein the ratio of the width of the first gap through which the welding strip passes to the width of the welding strip is configured to be 1.2 to 2.

[0008] According to an embodiment of the present invention, the welding strips are configured in an even number, and the numbers of the first gaps provided between the adjacent first electrodes with different polarities on the same battery cell are the same.

[0009] According to an embodiment of the present invention, the welding strips are configured in odd numbers, and the numbers of the first gaps provided between the adjacent first electrodes with different polarities on the same battery cell are different.

[0010] According to an embodiment of the present invention, the difference in number of the first gaps provided by the first electrodes with different polarities includes 1.

[0011] According to an embodiment of the present invention, the number of the first gaps provided in the same first electrode is 6 to 11.

[0012] According to an embodiment of the present invention, the number of the welding strips is 11 to 23, corresponding to the number of the first gaps provided in the first electrode.

[0013] According to an embodiment of the present invention, the back-contact battery string further includes an insulating layer made of an insulating material, and the insulating layer covers both ends of the first electrode segment.

[0014] According to an embodiment of the present invention, at a position of one end of the first electrode segment close to the welding strip, the thickness of the insulating layer decreases along a direction toward the welding strip.

[0015] According to an embodiment of the utility model, the ratio of the width of the above-mentioned welding strip to the width of the first gap between the two adjacent first electrode segments through which it passes is configured to be greater than or equal to 0.5, and the ratio of the width of the above-mentioned welding strip to the width of the second gap between the two adjacent insulating layers through which it passes is configured to be less than or equal to 0.75.

[0016] According to an embodiment of the utility model, the back-contact battery string also includes a plurality of second electrodes, and the second electrodes extend in a direction parallel to the second edge; wherein the second electrodes pass through a first gap formed by two adjacent first electrode segments of the first electrodes of different polarities, and are connected to the first electrode segments of the first electrodes of the same polarity.

[0017] According to an embodiment of the utility model, the welding strip is welded to the welding pad provided on the second electrode, and the ratio of the width of the welding strip to the width of the second gap between two adjacent insulating layers through which the welding strip passes is configured to be 0.6 to 1.2.

[0018] According to an embodiment of the present invention, the ratio of the sum of the first gaps between the plurality of first electrode segments of the first electrodes of different polarities to the length of the first electrode is configured to be different.

[0019] According to an embodiment of the present invention, the ratio of the sum of the first gaps between the plurality of first electrode segments of the first electrode configured as the positive electrode to the length of the first electrode is greater than the ratio of the sum of the first gaps between the plurality of first electrode segments of the first electrode configured as the negative electrode to the length of the first electrode.

[0020] An embodiment of the utility model further provides a photovoltaic assembly, comprising: a plurality of battery strings, wherein the plurality of battery strings are arranged at intervals.

[0021] According to the back contact cell string and photovoltaic module provided by the utility model, the length of the first electrode is configured to be greater than 98% of the length of the first side, so that the first electrode has a longer effective collection length; the ratio of the sum of the first gaps between the multiple first electrode segments of each first electrode to the length of the first electrode is less than or equal to 6%, further making the first electrode have a longer effective collection length, and making it difficult for the welding of the first electrode and the welding strip to short-circuit, so as to more effectively prevent leakage. In this way, the overall setting of the length of the first electrode segment and the width of the first gap is conducive to collecting the current generated by the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic structural diagram of a back-contact battery string according to an exemplary embodiment of the utility model; and

[0023] Figure 2 yes Figure 1 A partial cross-sectional view of portion A of a back-contact cell string of the exemplary embodiment shown.

[0024] In the drawings, the meanings of the reference numerals are as follows:

[0025] 1. Battery cells;

[0026] 2. Welding strip;

[0027] 21. The first welding strip;

[0028] 22. Second welding strip;

[0029] 3. a first electrode;

[0030] 31. a first electrode A;

[0031] 32. a first electrode B;

[0032] 4. Insulation layer; and

[0033] 5. Solder. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0035] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "include", "comprises", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0036] All terms used herein, including technical and scientific terms, have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0037] When using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, and C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc. When using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted as the meaning of the expression generally understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include but not be limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.

[0038] Back-contact cells have the characteristic of arranging both the positive electrode and the negative electrode on the back of the cell, which can reduce the coverage area of ​​the metal electrode on the front of the cell and have a higher energy conversion efficiency.

[0039] For example, a cell with n-type silicon as the main body has p+ doping area and n+ doping area arranged in parallel and spaced on the back side. The polarity of the first electrode arranged on and connected to the p+ doping area (i.e., the secondary gate) is configured as positive; similarly, the polarity of the first electrode arranged on and connected to the n+ doping area is configured as negative.

[0040] The first electrodes (i.e., auxiliary grids) of different polarities (i.e., positive and negative electrodes) need to be connected to the second electrodes (i.e., main grids) of the same polarity and / or welding strips to collect the current collected by the first electrodes. In order to insulate the first electrode from the second electrodes and / or welding strips of different polarities, the first electrode needs to be configured as a plurality of first electrode segments spaced apart so that the first gap formed between two adjacent first electrode segments allows the welding strip and / or the second electrode to pass through. If there are too many first gaps formed by adjacent first electrode segments in the first electrode, the effective collection length of the first electrode will be short; if there are too few first gaps, the length of each first electrode segment will be too long. Therefore, setting too many or too few first gaps is not conducive to current collection.

[0041] To this end, based on the same inventive concept, how to provide a back-contact cell string and photovoltaic module, so that through the design of the first electrode, the first electrode has a longer effective collection length, and the welding between the first electrode and the welding strip is not prone to short circuit, so as to more effectively prevent leakage, has become a technical problem that needs to be solved urgently.

[0042] Figure 1 It is a schematic structural diagram of a back-contact battery string according to an illustrative embodiment of the utility model.

[0043] According to a back contact battery string provided by the utility model, Figure 1 As shown, it includes a plurality of battery cells 1 and a plurality of first electrodes 3. Each battery cell 1 has a first side and a second side that are orthogonal to each other. The plurality of first electrodes 3 extend in a direction parallel to the first side, and are arranged on the back of the battery cell 1 at equal intervals along the extension direction of the second side, and each first electrode 3 includes a plurality of first electrode segments arranged at intervals. The ratio of the length of the first electrode 3 to the first side is greater than 98%, and the ratio of the sum of the first gaps between the plurality of first electrode segments of each first electrode 3 to the length of the first electrode 3 is less than or equal to 6%.

[0044] In an illustrative embodiment, Figure 1 As shown, the length of the first electrode 3 is characterized by the length of the first electrode 3 at both ends (i.e. Figure 1 Specifically, it includes the sum of the lengths of each first electrode segment constituting one first electrode 3 and the first gap formed by each two adjacent first electrode segments.

[0045] In such an embodiment, the length of the first electrode 3 is configured to be greater than 98% of the length of the first side, so that the first electrode 3 has a longer effective collection length; the ratio of the sum of the first gaps between the multiple first electrode segments of each first electrode 3 to the length of the first electrode is less than or equal to 6%, further making the first electrode have a longer effective collection length, and making it difficult for the welding of the first electrode and the welding strip to short-circuit, so as to more effectively prevent leakage. In this way, the overall setting of the length of the first electrode segment and the width of the first gap is conducive to collecting the current generated by the battery cell.

[0046] According to the embodiments of the present utility model, Figure 1 As shown, the back contact battery string further includes a plurality of second electrodes extending in a direction parallel to the second side, wherein the second electrode passes through a first gap formed by two adjacent first electrode segments of the first electrode 3 of different polarities and is connected to a first electrode segment of the first electrode 3 of the same polarity.

[0047] In an illustrative embodiment, Figure 1 As shown, the battery cell 1 includes but is not limited to a structure configured as a substantially rectangular shape. In detail, the battery cell 1 includes Figure 1 The first side (i.e., long side) and the second side (i.e., short side) are shown. Further, the length of the first side (i.e., long side) of each battery cell 1 includes but is not limited to being configured as any value between 180 mm and 190 mm, and the length of the second side (i.e., wide side) includes but is not limited to being configured as any value between 91 mm and 95 mm. It should be understood that the embodiments of the utility model are not limited thereto.

[0048] For example, the length of the second side may also be configured to be any value between 102 mm and 110 mm.

[0049] In an illustrative embodiment, Figure 1 As shown, the first electrode 3 (i.e., the auxiliary grid) and the second electrode (i.e., the main grid, which is blocked by the welding strip 2 and is not shown in the figure) are arranged on the back side of the battery cell (i.e., Figure 1 In detail, the first electrode 3 is arranged along a direction parallel to the first side (such as Figure 1 The second electrode is arranged to extend in a direction parallel to the second side (such as Figure 1 Further, the corresponding first electrode 3 includes a first electrode A31 and a first electrode B32 with different polarities (i.e., the first electrode A is a positive sub-grid, and the first electrode B is a negative sub-grid; or the first electrode A is a negative sub-grid, and the first electrode B is a positive sub-grid), and the second electrode passes through the first electrode A31 with different polarities in a direction orthogonal to the first electrode 3, and is connected to the middle of the first electrode B32 with the same polarity.

[0050] In an exemplary embodiment, the second electrode is parallel to the second side (eg Figure 1 A plurality of pads (not shown in the figure) are evenly spaced apart. In detail, the first electrode 3 is suitable for connecting to the pad or to the second electrode between adjacent pads. Further, the pad includes but is not limited to being configured as a rectangle, a polygon, a circle, an ellipse, a racetrack or any other shape. Among them, the first electrode 3 and / or the second electrode (including the pad) include but are not limited to being printed on the battery cell 1 through a corresponding screen.

[0051] In such an embodiment, the second electrode (i.e., the main grid) configured on the battery cell 1 is suitable for collecting the current collected by the first electrode 3 (i.e., the auxiliary grid). In addition, the plurality of second electrodes spaced apart on the battery cell 1 can also effectively limit the warping of the battery cell 1. It should be understood that the embodiments of the present utility model are not limited thereto.

[0052] For example, the back contact cell can also be configured as a busbar-less cell structure.

[0053] In the embodiment of the battery structure configured without a main grid, the first electrode 3 is directly connected to the welding strip 2 (ie, Figure 1 The first electrode 3 is connected to the second welding strip 22 as shown, so that the current collected by the first electrode 3 is directly collected through the welding strip 2. Different battery cells 1 are connected in series (such as in series) through the welding strip 2. In this way, the slurry used for printing the second electrode (i.e., the main grid) can be omitted, the screen design used for printing is simplified, and the resistance loss caused by the wider part of the connection position between the first electrode 3 and the second electrode is reduced. Among them, the welding strip 2 includes but is not limited to the use of a flat welding strip.

[0054] According to an embodiment of the present invention, which is not shown in the figure, the number of first gaps provided in the same first electrode 3 is configured to be 6 to 11.

[0055] According to an embodiment of the present invention, which is not shown in the figure, the number of the welding strips 2 is 11 to 23, corresponding to the number of the first gaps provided in the first electrode 3 .

[0056] In an illustrative embodiment, the number of first gaps formed by each first electrode 3 includes, but is not limited to, 6, 7, 8, 9, 10, 11 or any other number. Further, in response to the number of first electrodes formed by the first electrodes 3, the soldering strips 2 may be configured to be any number from 11 to 23, wherein the soldering strips 2 may preferably be configured to be twice the number of first gaps of the first electrodes 3 (i.e., if the first electrodes form n first gaps, 2n soldering strips 2 are configured).

[0057] For example, if n=6, 12 welding strips (i.e. 12BB) can be configured;

[0058] For another example, if n=11, 22 welding strips (ie, 22BB) can be configured.

[0059] It should be understood that the embodiments of the present invention are not limited thereto. The number of solder strips 2 can also be configured to be twice the number of first gaps of the first electrode 3, and increased or decreased by 1 (ie, if the first electrode forms n first gaps, 2n±1 solder strips 2 are configured).

[0060] For example, if n=6, 11 or 13 welding strips (i.e., 11BB or 13BB) can be configured;

[0061] For another example, if n=11, 21 or 23 welding strips (ie, 21BB or 23BB) can be configured.

[0062] Preferably, the number of the first gaps of the first electrode 3 may be 8 or 9 (ie, n=8 or 9), and the number of the welding strips 2 may be 15 to 19 (ie, 15BB to 19BB).

[0063] According to the embodiments of the present utility model, Figure 1 As shown, the back contact cell string further includes a welding strip 2, which passes through a first gap formed by two adjacent first electrode segments of a first electrode 3 and is connected to a first electrode segment of a first electrode 3 of another polarity. The ratio of the width of the first gap through which the welding strip 2 passes to the width of the welding strip 2 is configured to be 1.2-2.

[0064] In a preferred embodiment, the number of first gaps of the first electrode 3 is configured as 9 (i.e., n=9), and the number of welding strips 2 is configured as 18 (i.e., 18BB). In detail, the width of the first gap provided by the first electrode 3 includes but is not limited to being configured as 0.8 mm to 1.2 mm (i.e., Figure 1 d1 = 0.8 mm to 1.2 mm); the width of the solder strip 2 includes but is not limited to being configured as 0.6 mm (i.e. Figure 1 w = 0.6 mm). Further, the ratio of the width of the first gap through which the soldering ribbon 2 passes to the width of the soldering ribbon 2 is configured to be 1.2 / 0.6 to 0.8 / 0.6 (i.e. d1 / w = 2 to 1.33). Further, the length of the first electrode 3 includes but is not limited to being configured to be 180.328 mm (correspondingly, the length of the first electrode 3 should be greater than 98% of the length of the first side and less than 100%).

[0065] In such an embodiment, based on the above design, the number of first gaps of the first electrode 3 is configured to be 9, and the width of each first gap is configured to be 1.2 mm, so that the ratio of the sum of the first gaps between the multiple first electrode segments of the first electrode 3 to the length of the first electrode 3 (i.e., L=180.328 mm) is less than or equal to 6% (i.e., n*d1 / L=5.9%).

[0066] According to the embodiments of the present utility model, Figure 1 As shown, the ratios of the sum of the first gaps between the plurality of first electrode segments of the first electrodes 3 of different polarities to the length of the first electrode 3 are configured to be different.

[0067] According to an embodiment of the present invention, Figure 1 As shown, the ratio of the sum of the first gaps between the multiple first electrode segments of the first electrode 3 configured as the positive pole to the length of the first electrode 3 is greater than the ratio of the sum of the first gaps between the multiple first electrode segments of the first electrode 3 configured as the negative pole to the length of the first electrode 3.

[0068] In an exemplary embodiment, the first electrode A31 and the first electrode B32 are configured as a positive sub-grid and a negative sub-grid, respectively. In detail, the number of first gaps provided in the positive sub-grid and the negative sub-grid can be configured to be the same. Furthermore, the lengths of the positive sub-grid and the negative sub-grid can be configured to be equal. Furthermore, the width of the first gap formed by the positive sub-grid can be greater than the width of the first gap formed by the negative sub-grid (i.e., n*d1 正 / L>n*d1 负 / L).

[0069] In such an embodiment, in response to the characteristic of a larger n+ doped region configured in the back contact battery, under the premise that the lengths of the first electrodes 3 of different polarities are roughly the same and the number of configured first gaps is the same, the width of the first gap can be reduced so that the negative electrode sub-grid has a larger effective collection length, so that the current will not be too concentrated when passing through the negative electrode sub-grid.

[0070] According to the embodiments of the present utility model, Figure 1 As shown, the solder strips 2 are configured in odd numbers, and the numbers of first gaps arranged between adjacent first electrodes 3 with different polarities on the same battery cell 1 are different.

[0071] In an illustrative embodiment, Figure 1 As shown, the number of welding strips 2 includes but is not limited to 5 (ie an odd number), then the number of first gaps set by the first electrodes A31 with different polarities is 4, and the number of first gaps set by the first electrodes B32 is 3.

[0072] According to the embodiments of the present utility model, Figure 1 As shown, the difference in the number of first gaps provided for the first electrodes 3 having different polarities includes 1.

[0073] According to an embodiment of the present utility model, which is not shown in the figure, the welding strips 2 are configured as an even number, and the number of first gaps provided between adjacent first electrodes 3 with different polarities on the same battery cell 1 is the same.

[0074] In another exemplary embodiment, not shown in the figure, the number of the welding strips 2 includes but is not limited to 4 (i.e. an even number), then the number of first gaps provided by the first electrodes A31 with different polarities is 2, and the number of first gaps provided by the first electrodes B32 is 2. It should be understood that the above embodiment is exemplary, and the number of first gaps provided by the welding strips 2 and the first electrodes 3 can be set to any number that meets the design requirements of the back contact battery.

[0075] In a back contact battery, the interconnection between the battery cells 1 is mostly connected in series with the welding strip 2 through the welding points of the battery cell electrodes, and during lamination, the first electrode 3 (i.e., the secondary grid) and / or the second electrode (i.e., the main grid) form a battery string. When welding the welding strip 2 and the welding point, sufficient solder (such as solder or other bonding materials) must be configured to maintain the reliability of the welding position, but more solder may flow out to the adjacent first electrode 3 of different polarity during welding, thereby generating a short circuit risk. For this reason, a corresponding insulating layer needs to be provided to insulate the first electrode 3 from the welding strip 2.

[0076] Figure 2 yes Figure 1 A partial cross-sectional view of portion A of a back-contact cell string of the exemplary embodiment shown.

[0077] According to the embodiments of the present utility model, Figure 2 As shown, the back contact battery string further includes an insulating layer 4 made of an insulating material, and the insulating layer 4 covers both ends of the first electrode segment.

[0078] According to the embodiments of the present utility model, Figure 2 As shown, at one end of the first electrode segment close to the soldering strip 2 , the thickness of the insulating layer 4 decreases along the direction toward the soldering strip 2 .

[0079] In an illustrative embodiment, Figure 2 As shown, the insulating layer 4 includes but is not limited to being made of insulating glue (such as green glue). Figure 2 The thickness of the right end of the insulating layer 4 on the left side and the left end of the insulating layer 4 on the right side is configured to be smaller than the thickness of the proximal end of the insulating layer 4 (such as Figure 2The thickness of the left end of the insulating layer 4 on the left side and the right end of the insulating layer 4 on the right side is shown. Further, the thickness of the insulating layer 4 is configured to gradually decrease from the proximal end to the distal end.

[0080] In such an embodiment, the soldering tape 2 is printed and the soldering tape 2 (i.e. Figure 2 The first welding strip 21 shown in FIG. Figure 2 When the first electrode B32 shown in the figure is welded by solder 5 (such as solder), due to the accuracy limitation of the equipment (such as a machine and / or a welding machine), it is inevitable that the welding strip 2 and / or the solder 5 will be offset (such as the center line of the welding strip 2 and the center line of the first gap formed by two adjacent first electrode segments coincide with each other) relative to the ideal position (including but not limited to the orthographic projection along the thickness direction of the battery cell 1). Figure 2 To this end, the solder 5 (such as solder) should cover as much of the first electrode 3 (i.e., Figure 2 The first electrode B32 shown in FIG. Figure 2 However, this also leads to an increase in the consumption of insulating materials used to prepare the insulating layer 4, thereby increasing the manufacturing cost of the battery string. For this reason, the thickness of the far end of the insulating layer 4 is set to be smaller than the thickness of the near end to compensate for the consumption of insulating materials used to prepare the insulating layer 4; and the thicker part of the insulating layer 4 can more effectively prevent the problem of tip breakdown.

[0081] According to the embodiments of the present utility model, Figure 2 As shown, the ratio of the width of the welding strip 2 to the width of the first gap between two adjacent first electrode segments passed through is configured to be greater than or equal to 0.5, and the ratio of the width of the welding strip 2 to the width of the second gap between two adjacent insulating layers 4 passed through is configured to be less than or equal to 0.75.

[0082] In an illustrative embodiment, Figure 2 As shown in FIG. 1 , the back contact cell is configured as a cell structure without a main grid. Figure 2 w) and the width of the second gap between two adjacent insulating layers 4 through which the soldering strip 2 passes (i.e., Figure 2 The ratio of the width of the soldering strip 2 (ie, as shown in FIG. 2 ) is configured to be less than or equal to 0.75 (ie, w / d2≤0.75). Figure 2 The ratio of w) shown in the figure to the width of the first gap through which the soldering ribbon 2 passes is configured to be greater than or equal to 0.5 (ie, w / d1≤0.5).

[0083] For example, the width of the welding strip 2 is configured to be 0.6 mm (ie, w=0.6 mm), and the width of the second gap can be configured to be 0.8 mm to 1.2 mm (ie, d2=0.8 mm to 1.2 mm).

[0084] According to an embodiment of the utility model, not shown in the figure, the welding strip 2 is welded to the welding pad provided with the second electrode, and the ratio of the width of the welding strip 2 to the width of the second gap between two adjacent insulating layers 4 passed through is configured to be 0.6-1.2.

[0085] In an illustrative embodiment, not shown in the figure, the back contact cell is configured as a main grid (i.e., second electrode) cell structure. In detail, the ratio of the width of the solder strip 2 (i.e., w) to the width of the second gap between two adjacent insulating layers 4 through which the solder strip 2 passes (i.e., d2) is configured to be less than or equal to 1.2 and greater than or equal to 0.6 (i.e., 0.6≤w / d2≤1.2).

[0086] For example, the width of the welding strip 2 is configured to be 0.6 mm (ie, w=0.6 mm), and the width of the second gap can be configured to be 0.55 mm to 1.2 mm (ie, d2=0.55 mm to 1.2 mm).

[0087] In such an embodiment, based on the design of the first gap, the second gap and the width of the solder strip, the arranged insulating layer 4 can compensate for the offset position of the solder strip 2 and / or the solder 5, so that the solder strip 2 and / or the solder 5 are overlapped on at least one side (such as Figure 2 On the insulating layer 4 on the left and right sides (as shown), the first electrode 3 is insulated from the welding strip 2, thereby avoiding the occurrence of a short circuit.

[0088] A photovoltaic assembly provided by the utility model, which is not shown in the figure, includes a plurality of battery strings, and the plurality of battery strings are arranged at intervals.

[0089] In an exemplary embodiment, a plurality of battery strings are arranged in rows or columns and connected in parallel to form a photovoltaic module. Further, a plurality of battery cells 1 in the same battery string are connected in series via welding ribbons 2 .

[0090] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "back", "left", "right", etc., are only for reference to the drawings and are not intended to limit the scope of protection of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted when they may cause confusion in the understanding of the present invention.

[0091] The embodiments of the present invention are described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present invention is defined by the attached claims and their equivalents. Without departing from the scope of the present invention, a person skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A back contact battery string, characterized in that: include: A plurality of battery cells, each of the battery cells having a first side and a second side that are orthogonal to each other; A plurality of first electrodes extending in a direction parallel to the first side and arranged on the back side of the battery cell at equal intervals along the extending direction of the second side, each of the first electrodes comprising a plurality of first electrode segments arranged at intervals; The ratio of the length of the first electrode to the first side is greater than 98%, and the ratio of the sum of the first gaps between the first electrode segments of each first electrode to the length of the first electrode is less than or equal to 6%.

2. The battery string according to claim 1, characterized in that: Also included is a welding strip, wherein the welding strip passes through a first gap formed by two adjacent first electrode segments of one first electrode and is connected to a first electrode segment of the first electrode of another polarity; Wherein, the ratio of the width of the first gap through which the welding strip passes to the width of the welding strip is configured to be 1.2-2.

3. The battery string according to claim 2, characterized in that: The welding strips are configured in an even number, and the numbers of the first gaps arranged between the adjacent first electrodes with different polarities on the same battery cell are the same.

4. The battery string according to claim 2, characterized in that: The welding strips are configured in an odd number, and the numbers of the first gaps arranged between the adjacent first electrodes with different polarities on the same battery cell are different.

5. The battery string according to claim 4, characterized in that: A difference in the number of the first gaps provided by the first electrodes having different polarities includes 1.

6. The battery string according to claim 2, characterized in that: The number of the first gaps provided in the same first electrode is configured to be 6 to 11.

7. The battery string according to claim 6, characterized in that: The number of the welding strips is 11 to 23, corresponding to the number of the first gaps provided in the first electrode.

8. The battery string according to any one of claims 2 to 7, characterized in that: It also includes an insulating layer made of insulating material, and the insulating layer covers both ends of the first electrode segment.

9. The battery string according to claim 8, characterized in that: At an end of the first electrode segment close to the welding strip, the thickness of the insulating layer decreases along a direction toward the welding strip.

10. The battery string according to claim 8, characterized in that: The ratio of the width of the welding strip to the width of the first gap between two adjacent first electrode segments through which the welding strip passes is configured to be greater than or equal to 0.5, and the ratio of the width of the welding strip to the width of the second gap between two adjacent insulating layers through which the welding strip passes is configured to be less than or equal to 0.

75.

11. The battery string according to claim 8, characterized in that: Also comprising a plurality of second electrodes, the second electrodes extending in a direction parallel to the second side; The second electrode passes through a first gap formed by two adjacent first electrode segments of the first electrode with different polarities, and is connected to the first electrode segment of the first electrode with the same polarity.

12. The battery string according to claim 11, characterized in that: The welding strip is welded to a welding pad provided with the second electrode, and a ratio of a width of the welding strip to a width of a second gap between two adjacent insulating layers through which the welding strip passes is configured to be 0.6 to 1.

2.

13. The battery string according to any one of claims 1 to 7, characterized in that: The ratios of the sum of the first gaps between the plurality of first electrode segments of the first electrodes of different polarities to the length of the first electrode are configured to be different.

14. The battery string according to claim 13, characterized in that: The ratio of the sum of the first gaps between the plurality of first electrode segments of the first electrode configured as the positive electrode to the length of the first electrode is greater than the ratio of the sum of the first gaps between the plurality of first electrode segments of the first electrode configured as the negative electrode to the length of the first electrode.

15. A photovoltaic module, characterized in that: include: A plurality of battery strings as claimed in any one of claims 1 to 14, wherein the plurality of battery strings are arranged at intervals.

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