Photovoltaic module and cell

Abstract

The application provides a photovoltaic module and a cell. The photovoltaic module comprises at least two cell strings, at least one bus bar, the cell string comprises at least two cell pieces and an interconnecting piece, the adjacent cell pieces are electrically connected through the interconnecting piece, the bus bar is electrically connected with the at least two cell strings, the first surface of the cell piece is provided with an electrode, the electrode comprises a current collecting electrode and a bus electrode, for the first cell piece adjacent to the bus bar, the distance between the first bus electrode adjacent to the first side edge and the first current collecting electrode in the first cell piece is greater than or equal to 230 mu m-d, d is the thickness of the first cell piece, and the first side edge is the side edge of the first cell piece close to the bus bar; the first current collecting electrode is the current collecting electrode adjacent to the first bus electrode and having the same polarity as the first bus electrode. The application reduces the probability of hidden cracks of the first cell piece at the position close to the bus bar in the process of the overlay welding and the subsequent laminating, thereby improving the cell quality.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic cells, and in particular to a photovoltaic module and a cell. Background Art

[0002] The output power and voltage of a single solar cell are typically low. To achieve the output power required for practical applications, multiple cells are combined in series and parallel to form a solar photovoltaic module. The electrical structure design of a solar module is based on the principles of "series" and "parallel" to optimize the overall voltage, current, and power output.

[0003] A battery string generally refers to a plurality of solar cells connected in series to form an electrical connection, in which the positive electrode of each solar cell is electrically connected to the negative electrode of the next cell through an interconnect.

[0004] In the production of photovoltaic modules, welding is a key process step. However, this process inevitably involves high-temperature heating. Due to the difference in thermal expansion coefficients between the interconnects and the solar cell silicon wafer material itself, the soldering process will be significantly affected by the "thermal expansion and contraction" effect. Specifically, this manifests as a stress difference between the interconnects and the cells, which in turn causes significant warping of the solar cells. Warped cells are subjected to compressive stress during automated paving or stacking, increasing the chance of breakage. Under the high temperature and high pressure of the lamination process, stress is further concentrated, which may cause hidden cracks in the cells, thereby weakening the power generation performance of the module. Summary of the Invention

[0005] The present invention provides a photovoltaic module and a solar cell to solve the problem of hidden cracks in the solar cell in the prior art.

[0006] In order to solve the above problems, the present invention is achieved as follows:

[0007] In a first aspect, an embodiment of the present invention provides a photovoltaic module, including:

[0008] at least two battery strings and at least one bus bar;

[0009] The battery string includes: at least two battery cells and an interconnector; adjacent battery cells are electrically connected via the interconnector; the busbar is electrically connected to at least two battery strings; the battery cell includes a first surface and a second surface, electrodes are provided on the first surface, and the electrodes include: a collector electrode and a bus electrode;

[0010] A first battery cell adjacent to the bus bar, a distance s between a first bus electrode adjacent to a first side in the first battery cell and a first collecting electrode is ≥ 230 μm-d, where d is a thickness of the first battery cell, and the first side is an edge of the first battery cell close to the bus bar; the first collecting electrode is a collecting electrode adjacent to the first bus electrode and having the same polarity as the first bus electrode.

[0011] Optionally, the distance s≤430 μm-d.

[0012] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0013] Optionally, the ratio of the width of the first collecting electrode in the first direction to the width of the first bus electrode in the first direction is 0.008-0.064;

[0014] The first direction is perpendicular to the extending direction of the collecting electrode.

[0015] Optionally, for the second collecting electrode overlapping with the first bus electrode, along the first direction, the width of the first bus electrode is w, and the distance between the second collecting electrode and the side of the first bus electrode is L;

[0016] 0.08×w≤L≤0.5×w;

[0017] The first direction is perpendicular to the extending direction of the collecting electrode, and the second collecting electrode and the first bus electrode have the same polarity.

[0018] Optionally, a difference between the thickness of the first bus electrode and the thickness of the second collecting electrode is 3-6 μm.

[0019] Optionally, the segments of the first collecting electrode corresponding to the first bus electrode are coated with an insulating adhesive layer; the first collecting electrode collects the current to the first bus electrode through a connecting wire;

[0020] The length of the insulating rubber layer is greater than or equal to the length of the first bus electrode in the second direction;

[0021] The width of the insulating adhesive layer is ≥ the width of the first collecting electrode + 50 μm;

[0022] The second direction is parallel to the extending direction of the collecting electrode.

[0023] Optionally, for a third current collecting electrode adjacent to the first busbar electrode, a segment of the third current collecting electrode corresponding to the first busbar electrode is truncated; the length of the truncation is greater than or equal to the length of the first busbar electrode in the second direction; and the polarity of the third current collecting electrode is different from the polarity of the first busbar electrode.

[0024] Optionally, the busbar is arranged at a middle position and / or an end position of the photovoltaic module.

[0025] In a second aspect, an embodiment of the present application provides a battery piece, comprising a first surface and a second surface, the first surface being provided with an electrode, the electrode comprising: a current collecting electrode and a busbar electrode.

[0026] The busbar electrode and the first current collecting electrode are spaced apart by a distance s; the distance s is greater than or equal to 230μm-d, d being the thickness of the first battery piece, and the first current collecting electrode being adjacent to the busbar electrode and having the same polarity as the busbar electrode.

[0027] Optionally, the distance s is less than or equal to 430μm-d.

[0028] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0029] Optionally, the ratio of the width of the first current collecting electrode in a first direction to the width of the busbar electrode in the first direction is 0.008-0.064.

[0030] The first direction is perpendicular to the extension direction of the current collecting electrode.

[0031] Optionally, for a second current collecting electrode overlapping the busbar electrode, the width of the busbar electrode in a first direction is w, and the distance between the second current collecting electrode and the side edge of the busbar electrode is L.

[0032] 0.08×w≤L≤0.5×w.

[0033] The first direction is perpendicular to the extension direction of the current collecting electrode, and the second current collecting electrode has the same polarity as the busbar electrode.

[0034] The embodiment of the present invention can set the distance s between the first bus electrode and the first collecting electrode. By setting the distance s, a suitable buffer interval can be provided between the first collecting electrode and the first bus electrode. Therefore, the stress generated on the first collecting electrode has a weakened effect on the first bus electrode. Moreover, since the first bus electrode is located at the end position where the bus bar is arranged in the battery cell, the stress concentration at the position close to the bus bar in the first battery at the head and tail of the battery string is reduced, thereby reducing the probability of hidden cracks in the first battery cell near the bus bar during the lap welding and subsequent lamination processes, thereby improving the battery quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0036] Figure 1 This is a schematic diagram of the layout structure of a photovoltaic module according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the appearance structure of a battery cell according to an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of a partial structure of a battery cell according to an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of the partial structure of another battery cell according to an embodiment of the present invention;

[0040] Figure 5 A schematic diagram of the partial structure of another battery cell according to an embodiment of the present invention;

[0041] Figure 6 This is an enlarged schematic diagram of a local structure of a battery cell according to an embodiment of the present invention;

[0042] Figure 7 A schematic diagram of the division of measurement points of a battery cell according to an embodiment of the present invention;

[0043] Figure 8 This is a schematic structural diagram of a bus electrode and a collector electrode according to an embodiment of the present invention;

[0044] Figure 9 This is a schematic structural diagram of another bus electrode and collector electrode according to an embodiment of the present invention.

[0045] Reference numerals:

[0046] 10-battery string; 11-battery cell; 111-first battery cell; 20-bus bar; 30-electrode; 31-collecting electrode; 311-first polarity collecting electrode; 312-second polarity collecting electrode; 311a-first collecting electrode; 311b-second collecting electrode; 311c-third collecting electrode; 32-bus electrode; 321-first bus electrode; 322-second polarity bus electrode; 321a-fourth bus electrode; 40-insulating adhesive layer; 41-connecting wire; 50-interconnection; A-first region; B-first surface; C1-segment; A1-first side; C-battery string group; X-first direction; Y-second direction; D-second region. DETAILED DESCRIPTION

[0047] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention may be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0048] like Figure 1 As shown, the present invention provides a photovoltaic module, comprising: at least two battery strings 10, at least one bus bar 20; the battery string 10 comprises: at least two battery cells 11 and an interconnector 50; adjacent battery cells 11 are electrically connected via the interconnector 50; the bus bar 20 is electrically connected to the at least two battery strings 10; further referring to Figure 2 and Figure 3 The cell 11 includes a first surface B and a second surface. The first surface B is provided with an electrode 30. The electrode 30 includes: a collector electrode 31 and a bus electrode 32. For the first cell 111 adjacent to the bus bar 20 (i.e., the cell in the first area A), further reference is made to Figure 4 The distance s between the first bus electrode 321 and the first collecting electrode 311a adjacent to the first side A1 in the first battery cell 111 is ≥ 230 μm-d, where d is the thickness of the first battery cell; the first side A1 is the side of the first battery cell 111 close to the bus bar 20; the first collecting electrode 311a is a collecting electrode 31 adjacent to the first bus electrode 321 and having the same polarity as the first bus electrode 321.

[0049] In the embodiment of the present invention, a photovoltaic module is formed by electrically connecting a plurality of solar cells. Figure 1 , the battery string 10 is a battery cell 11 ( Figure 1The battery string 10 shown includes 10 battery cells 11 connected in series to form a series structure. The battery strings 10 are interconnected by bus bars 20 to form battery string groups C. Figure 1 The battery structure shown includes 6 battery strings, and 12 battery strings 10 are connected in parallel to form the battery structure of the photovoltaic module. In addition, during the preparation of the photovoltaic module, welding and lamination of the interconnection member 50 and the busbar electrode 32 are required. Among them, the busbar 20 is usually set at both ends and / or in the middle of the photovoltaic module, such as Figure 1 After multiple battery strings C are connected in parallel, the busbar 20 is usually arranged on the same side of the multiple battery strings C arranged side by side, and / or is arranged at a position close to the same side of the multiple battery strings C arranged side by side. The interconnection member 50 can be in the form of a welding ribbon, including a tin-containing welding ribbon, an alloy welding ribbon, a tin-free welding ribbon, etc.

[0050] For some examples, refer to Figure 1 Each battery string group C can be connected in reverse parallel with a bypass diode. This can ensure that when the battery cells in the battery string group C are blocked, the bypass diode will at least not affect the battery cells outside the blocked battery string group C, thereby effectively preventing the hot spot effect.

[0051] For some examples, refer to Figure 4 The first collecting electrode 311 a adjacent to the first bus electrode 321 may be located above the first bus electrode 321 .

[0052] In other examples, refer to Figure 5 The first collecting electrode 311 a adjacent to the first bus electrode 321 may be located below the first bus electrode 321 .

[0053] In other examples, refer to Figure 6 The first collecting electrode 311 a adjacent to the first bus electrode 321 may include the first collecting electrode 311 a above the first bus electrode 321 and the first collecting electrode 311 a below the first bus electrode 321 .

[0054] The cell in the photovoltaic module of the embodiment of the present invention may be a back contact cell, referring to Figure 2 and Figure 3 The electrode 30 is provided on the first surface B (backlight side) of the cell 11. The electrode 30 includes a collector electrode 31 and a bus electrode 32. The collector electrode 31 is generally used to collect and transmit current, and the bus electrode 32 is generally used to collect and output current. The bus electrode 32 can extend along a first direction X, and the collector electrode can extend along a second direction Y. The first direction X is perpendicular to the second direction Y.

[0055] The collector electrode 31 can generally be a thin grid line. In one embodiment, the busbar electrode 32 can include pads and a busbar extending in the first direction X. In another embodiment, the busbar electrode 32 can include only pads extending in the first direction X (without a busbar structure). In both embodiments, the pads can include a first busbar electrode 321 positioned near the busbar 20 in the cell 11, and a plurality of fourth busbar electrodes 321a positioned near the center of the cell 11. The dimensions of the first busbar electrode 321 can be greater than, equal to, or smaller than those of the fourth busbar electrodes 321a. Dimensions can include length, width, area, etc.

[0056] Taking the example that the size of the first bus electrode 321 is larger than the size of the fourth bus electrode 321a, the width of the first bus electrode 321 may be larger than the width of the fourth bus electrode 321a, the length of the first bus electrode 321 may be larger than the length of the fourth bus electrode 321a, or both the length and width of the first bus electrode 321 may be larger than the length and width of the fourth bus electrode 321a.

[0057] The pads can also include large pads located near the busbar 20 of the cell 11, and multiple welding areas located near the middle of the cell 11. The collector electrode can be provided with a thickened section (partial or entire areas of the thickened section can be thicker than the collector electrode, and the thickened section is in the shape of a straight line or an I-shaped section), or only with a thin grid, and the welding strip is welded to the thin grid. The pad (i.e., the busbar electrode 32) contains tin and silver, and is used to weld to the interconnection component. Figure 2 、 Figure 3 The cell is shown to be a busbar-less cell, so no busbar structure is provided in the second region D. That is, the cell 11 collects and outputs current through a plurality of bus electrodes 32 (ie, pads) arranged along the first direction X.

[0058] In addition, the battery cell 11 may have two different polarities, a first polarity and a second polarity, such as the first polarity is positive and the second polarity is negative, or the first polarity is negative and the second polarity is positive. According to polarity classification, the collector electrode 31 may include a first polarity collector electrode 311 ( Figure 3 thick solid line) and the second polarity collecting electrode 312 ( Figure 3 (thin dashed line in the middle), along the first direction X, the first polarity collecting electrode 311 and the second polarity collecting electrode 312 are arranged alternately; the bus electrode 32 may include a first polarity bus electrode and a second polarity bus electrode 322; along the second direction Y, the first polarity bus electrode and the second polarity bus electrode 322 are arranged alternately. The first polarity bus electrode is used to conduct with the first polarity collecting electrode 311, and the second polarity bus electrode 322 is used to conduct with the second polarity collecting electrode 312. Figure 3In the figure, the left side is a row of first polarity bus electrodes, the middle is a row of second polarity bus electrodes 322, and the right side is a row of first polarity bus electrodes; starting from the first side A1 of the battery cell 11 along the first direction X, the first row is the second polarity collecting electrodes 312, the second row is the first polarity collecting electrodes 311, the third row is the second polarity collecting electrodes 312, and so on.

[0059] Further, refer to Figure 3 For a column of bus electrodes with the same polarity, the size of a first bus electrode 321 close to the first side A1 is larger, while the sizes of multiple fourth bus electrodes 321a away from the first side A1 are smaller.

[0060] During the high-temperature heating process of welding, the back-contact cell will be warped due to the different expansion coefficients of the interconnect and the silicon wafer. In addition, since the positive and negative electrodes of the back-contact cell are on the back of the cell, the warping is 3-5mm higher than that of the double-sided interconnected cell. The double-sided interconnected cell is such as the tunnel oxide passivated contact cell (TOPCon). The front of the TOPCon cell has the same structure as a conventional N-type solar cell. The main difference is that an ultra-thin silicon oxide layer is prepared on the back of the cell, and then a thin layer of doped silicon is deposited. The two together form a passivated contact structure, which effectively reduces surface recombination and metal contact recombination.

[0061] For back-contact cells, cells at the head and tail of a string experience greater warpage than cells in the middle, as there's no force acting on them from other cells. During the stack welding and subsequent lamination processes, this increased warpage at the head and tail leads to a higher proportion of hidden crack fragments, accounting for 70%-80% of all hidden crack fragments.

[0062] Furthermore, 90% of the hidden cracks in the head and tail cells are concentrated on the busbars near the end edges of the cells. Therefore, the present invention requires analyzing the topography of the busbars near the end edges of the cells to address the hidden cracks there.

[0063] In the related art, to collect current, the collector electrode near the busbar passes through or is adjacent to the busbar electrode. The distance between the two is random, and the related art does not specify a specific range for this distance. Consequently, during the soldering process of the cell interconnects, the tin on the solder ribbon does not wet the non-electrode-covered surfaces of the cell. Because the busbar electrode material has a high silver content (typically 60%-80%), and the collector electrode has an even higher silver content (typically above 90%), tin from the lower-silver-content device migrates toward the higher-silver-content device. Therefore, when the first busbar electrode and the first collector electrode are very close, or when the first collector electrode passes through the first busbar electrode, tin on the first busbar electrode (large pad) and / or tin on the interconnect can flow and accumulate on the first collector grid, increasing stress at the first collector electrode. This results in a high probability of cell cracking during the stitching and subsequent lamination processes. Such cracked cells can significantly reduce the photoelectric conversion efficiency, thus affecting battery quality.

[0064] To solve this problem, refer to Figures 1-4 , the embodiment of the present invention can be directed to the first battery cell 111 ( Figure 1 The battery cells in area A in the middle of the battery string 10 are processed, with specific improvements focused on the first busbar 321 of the first battery cell 111 adjacent to the first side A1. The first battery cells 111 are located at the head and tail of the battery string 10. These battery cells have a greater warpage than battery cells in other locations and are more prone to hidden cracks. Furthermore, the first busbar 321 of the first battery cell 111 adjacent to the first side A1 is a high-risk location for hidden cracks.

[0065] In an embodiment of the present invention, a distance s can be set between the first bus electrode 321 and the first collecting electrode 311a, wherein the first collecting electrode 311a is a collecting electrode adjacent to the first bus electrode 321 and having the same polarity as the first bus electrode 321. By setting the distance s between the first bus electrode 321 and the first collecting electrode 311a, a suitable buffer gap can be provided between the first collecting electrode 311a and the first bus electrode 321, thereby avoiding the above-mentioned adverse effects. By setting the distance s, the present invention can provide a suitable buffer gap between the first collecting electrode and the first bus electrode, thereby reducing the influence of the stress generated on the first collecting electrode on the first bus electrode. Moreover, since the first bus electrode is located at the end position where the bus bar is arranged in the battery cell, the stress concentration near the bus bar in the first battery cell at the head and tail of the battery string is reduced, thereby reducing the probability of hidden cracks in the first battery cell near the bus bar during the stitch welding and subsequent lamination processes, thereby improving the battery quality.

[0066] It should be noted that, referring toFigure 4 The distance s refers to the vertical distance between the side of the first collecting electrode 311a close to the first bus electrode 321 and the target side of the first bus electrode 321. The target side is the side of the first bus electrode 321 closest to the first collecting electrode 311a.

[0067] In summary, the embodiment of the present invention can set the distance s between the first bus electrode and the first collecting electrode. By setting the distance s, a suitable buffer interval can be provided between the first collecting electrode and the first bus electrode. Therefore, the stress generated on the first collecting electrode has a weakened effect on the first bus electrode. Moreover, since the first bus electrode is located at the end position where the bus bar is arranged in the battery cell, the stress concentration at the position close to the bus bar in the first battery at the head and tail of the battery string is reduced, thereby reducing the probability of hidden cracks in the first battery cell near the bus bar during the lap welding and subsequent lamination processes, thereby improving the battery quality.

[0068] In the embodiment of the present invention, the thickness of the battery cell can be measured in the following manner:

[0069] Preparation: The measurement personnel should wear anti-static clothing and nitrile gloves.

[0070] Equipment used: A height gauge that has passed calibration and is within the calibration validity period. The measurement accuracy of the height gauge must be no less than 1um.

[0071] Measurement steps:

[0072] 1. Check the sampling quantity according to the sampling characterization and the sampling table, randomly select the corresponding number of battery cells for testing, and handle the battery cells with care to avoid damage.

[0073] 2. Clear the height gauge on the platform, take the battery cells in order (with the adhesive side facing up), and follow Figure 7 According to the measurement point requirements, avoid the glue position and measure the thickness of measurement points 1, 2, 3, 4, and 5 in turn, and record the measurement data.

[0074] 3. Repeat step 2 to complete the thickness measurement of other sampled cells.

[0075] 4. Calculate the average of the thickness values ​​recorded at measurement points 1, 2, 3, 4, and 5 as the value of d.

[0076] Optionally, the distance s≥230 μm-d, with the unit being micrometer.

[0077] Optionally, the distance s≤430μm-d, and the unit is micrometer.

[0078] Combined with the above definition, 230μm-d≤distance s≤430μm-d. In the embodiment of the present invention, the distance s can solve the problem of cell fragmentation near the busbar in the photovoltaic module. However, the distance s cannot be too large. If the distance s is too large (exceeding the upper limit of its range), the arrangement of the collector electrodes will be too sparse, the distance between the collector electrodes of the same polarity will be too large, the carrier transmission distance will be too long, and the carriers will easily recombine during the transmission process, which is not conducive to the current collection of the cell and affects the battery efficiency. In addition, by reducing the width w of the first bus electrode in the first direction X, the distance s can be increased. However, if the width w of the first bus electrode in the first direction X is too small, the area of ​​the first bus electrode will be reduced, thereby making the welding pull-out force of the first bus electrode insufficient, affecting the overall reliability, so the distance s cannot be too large.

[0079] For example, if the thickness d of the first battery cell is 100 μm, then 130 μm≤distance s≤330 μm.

[0080] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0081] In an embodiment of the present invention, the thickness d of the first battery cell is set in a range of 60 μm-150 μm; the distance s can be set in a range of 100 μm-300 μm; based on the analysis of the upper and lower limits of the range, the relationship between the distance s and the thickness d is obtained: 2d / 3≤s≤5d.

[0082] In an embodiment of the present invention, the cell used in the photovoltaic module can be selected first, and then the distance s can be determined based on the thickness of the cell. The thinner the first cell, the lower the cost. However, the thickness of the first cell cannot be too small. If the thickness is too small, it will affect the light absorption effect of the first cell and make the first cell fragile, thereby affecting the optical and mechanical properties of the first cell. The thicker the first cell, the better the mechanical strength of the first cell, and the smaller the required distance s; the smaller the thickness of the first cell, the weaker the mechanical strength of the first cell, and the larger the required distance s. The mechanical strength of the first cell can be reflected in its bending resistance and compressive strength. The thicker the first cell, the better the bending resistance and compressive strength of the first cell.

[0083] Optional, see Figure 4 The ratio of the width of the first collecting electrode 311a in the first direction X to the width of the first bus electrode 321 in the first direction X is 0.008-0.064, and the first direction X is perpendicular to the extending direction Y of the collecting electrode.

[0084] In the embodiment of the present invention, the ratio of the width of the first collecting electrode 311 a in the first direction X to the width w of the first bus electrode 321 in the first direction X is 0.008-0.064, for example, the ratio may be 0.048.

[0085] The width of the first collecting electrode in the first direction X ranges from 0.01 mm to 0.08 mm. This width range allows the first collecting electrode to be narrower, thereby reducing the shading interference to the cell during illumination, thereby improving the optical performance of the cell.

[0086] The width of the first bus electrode in the first direction X is 1.25 mm. The width of the first bus electrode in the first direction X is wider, so that the contact area between the first bus electrode and the welding strip is larger, thereby improving the connection performance. In addition, the width of the first bus electrode in the first direction X is larger, so that the area of ​​the first bus electrode can be larger. When the area of ​​the first bus electrode is larger, the thickness of the first bus electrode can be smaller, thereby saving material costs.

[0087] The calculation process of the upper and lower boundary values ​​of the range of this ratio is: the ratio of the minimum width of the first collecting electrode in the first direction, 0.01mm, to the width of the first bus electrode in the first direction, 1.25mm, is the lower boundary value of the range of this ratio, 0.008mm; the ratio of the maximum width of the first collecting electrode in the first direction, 0.08mm, to the width of the first bus electrode in the first direction, 1.25mm, is the upper boundary value of the range of this ratio, 0.064mm.

[0088] If this ratio is too large, more tin will accumulate on the first collecting electrode, causing more severe stress concentration at the first collecting electrode, and increasing the probability of subsequent cell cracking. Therefore, this ratio should be as small as possible. However, this ratio cannot be too small, as it will cause the first collecting electrode to be too thin, thereby affecting current transmission efficiency. Therefore, in this embodiment of the present invention, the ratio of the width of the first collecting electrode 311a in the first direction X to the width of the first bus electrode 321 in the first direction X is set within the range of 0.008-0.064. This ensures that the current transmission efficiency of the first collecting electrode meets the requirements while reducing stress concentration at the first collecting electrode, thereby reducing the probability of subsequent cell cracking.

[0089] Optional, see Figure 4 For the second collecting electrode 311 b overlapping the first bus electrode 321 , along the first direction X, the width of the first bus electrode is w, and the distance between the second collecting electrode 311 b and the side of the first bus electrode 321 is L.

[0090] 0.08×w≤L≤0.5×w;

[0091] The first direction X is perpendicular to the extending direction Y of the collecting electrode. The second collecting electrode 311 b has the same polarity as the first bus electrode 321 .

[0092] In the embodiment of the present invention, for the second collecting electrode 311b of the same polarity overlapping the first bus electrode 321, the distance L between the second collecting electrode 311b and the side of the first bus electrode 321 has the following relationship with the width w of the first bus electrode:

[0093] 0.08×w≤L≤0.5×w; in this way, a certain safety distance can be spaced between the second collecting electrode 311b and the side of the first bus electrode 321 as a buffer, so that when the interconnection parts are subsequently welded, the aggregation phenomenon of tin on the interconnection parts to the silver on the second collecting electrode is weakened, thereby reducing the stress concentration on the second collecting electrode, thereby reducing the probability of hidden cracks in the battery cell during the lap welding and subsequent lamination processes, and improving the battery quality.

[0094] Optionally, the difference between the thickness of the first busbar electrode and the thickness of the second collector electrode is 3-6 μm. In the thickness direction of the cell, the first busbar electrode is higher and the thickness of the second collector electrode is lower.

[0095] For example, the difference between the thickness of the first bus electrode and the thickness of the second collector electrode may be any value among 3 μm, 4 μm, 5 μm, and 6 μm.

[0096] The second collector electrode is thicker than the first busbar electrode. A thickness difference of 3-6 μm between the first and second collector electrodes allows the second collector electrode to be thicker and narrower, reducing the shading effect of the second collector electrode on the cell during illumination and ensuring better conductivity. Furthermore, making the first busbar electrode as thin as possible saves material costs.

[0097] Optional, see Figure 8 The segments of the first collecting electrode 311 a corresponding to the first bus electrode 321 are coated with an insulating adhesive layer 40 ; the first collecting electrode 311 a collects the current to the first bus electrode 321 through the connecting wire 41 .

[0098] The length L1 of the insulating rubber layer is greater than or equal to the length h of the first bus electrode in the second direction Y;

[0099] The width w1 of the insulating adhesive layer is ≥ the width of the first collecting electrode + 50 μm;

[0100] The second direction Y is parallel to the extending direction of the collecting electrodes.

[0101] In an embodiment of the present invention, by coating the segments of the first collecting electrode 311a corresponding to the first bus electrode 321 with an insulating adhesive layer 40 of appropriate length and width, the insulating adhesive layer 40 can reduce the aggregation of tin on the interconnects toward the silver on the first collecting electrode during subsequent soldering of the interconnects, thereby reducing stress concentration on the first collecting electrode. This, in turn, reduces the probability of hidden cracks in the cell during the stitching and subsequent lamination processes, thereby improving battery quality. Although the segments of the first collecting electrode 311a corresponding to the first bus electrode 321 are coated with an insulating adhesive layer 40, the first collecting electrode 311a collects current to the first bus electrode 321 via the connecting wire 41. Therefore, this design does not affect the first collecting electrode's function of collecting and transmitting current.

[0102] Optional, see Figure 9 For the third collecting electrode 311c adjacent to the first bus electrode 321, the segment C1 of the third collecting electrode 311c corresponding to the first bus electrode 321 is cut off; the cut length L2 is ≥ the length h of the first bus electrode 321 in the second direction Y; the polarity of the third collecting electrode 311c is different from the polarity of the first bus electrode 321.

[0103] In an embodiment of the present invention, in one implementation, the third collecting electrode 311 c of different polarity adjacent to the first bus electrode 321 can be cut off at the segment C1 corresponding to the first bus electrode 321, thereby avoiding the adjacent third collecting electrode 311 c of different polarity being connected to the first bus electrode 321 and causing a short circuit.

[0104] Optional, see Figure 1 The busbar 20 is arranged at the middle position and / or at both ends of the photovoltaic module.

[0105] The busbars 20 are usually arranged at both ends and / or in the middle of the photovoltaic module. Figure 1 That is, after the multiple battery strings are connected in parallel, the bus bar 20 is usually arranged on the same side of the multiple battery strings arranged side by side, and / or is arranged at a position close to the same side of the multiple battery strings arranged side by side.

[0106] In summary, the embodiment of the present invention can set the distance s between the first bus electrode and the first collecting electrode. By setting the distance s, a suitable buffer interval can be provided between the first collecting electrode and the first bus electrode. Therefore, the stress generated on the first collecting electrode has a weakened effect on the first bus electrode. Moreover, since the first bus electrode is located at the end position where the bus bar is arranged in the battery cell, the stress concentration at the position close to the bus bar in the first battery at the head and tail of the battery string is reduced, thereby reducing the probability of hidden cracks in the first battery cell near the bus bar during the lap welding and subsequent lamination processes, thereby improving the battery quality.

[0107] Reference Figures 2-4 An embodiment of the present invention provides a battery cell, wherein the battery cell 11 includes a first surface and a second surface. An electrode 30 is provided on the first surface, and the electrode 30 includes: a collecting electrode 31 and a bus electrode 32; a distance s between the bus electrode 32 and the first collecting electrode 311a is ≥ 230 μm-d, where d is the thickness of the first battery cell; and the first collecting electrode 311a is a collecting electrode adjacent to the bus electrode 32 and has the same polarity as the bus electrode 32.

[0108] The cell 11 may be any cell in a photovoltaic module, and the bus electrode 32 may be any bus electrode among all the bus electrodes 32 included in the cell 11 .

[0109] In an embodiment of the present invention, a distance s can be set between the bus electrode 32 and its corresponding first collecting electrode 311a, wherein the first collecting electrode 311a is a collecting electrode adjacent to the bus electrode 32 and has the same polarity as the bus electrode 32. By setting the distance s between the bus electrode 32 and the corresponding first collecting electrode 311a, a suitable buffer interval can be provided between the first collecting electrode and the corresponding bus electrode. Therefore, the influence of the stress generated on the first collecting electrode on the bus electrode is weakened, thereby reducing the probability of hidden cracks in the battery cell during the lap welding and subsequent lamination processes, and improving the battery quality.

[0110] Optional, s≤430μm-d.

[0111] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0112] Optionally, the ratio of the width of the first collecting electrode in the first direction to the width of the bus electrode in the first direction is 0.008-0.064;

[0113] The first direction is perpendicular to the extending direction of the collecting electrode.

[0114] Optionally, for the second collecting electrode overlapping the bus electrode, along the first direction, the width of the bus electrode is w, and the distance between the second collecting electrode and the side of the bus electrode is L;

[0115] 0.08×w≤L≤0.5×w;

[0116] The first direction is perpendicular to the extending direction of the collecting electrode, and the second collecting electrode has the same polarity as the bus electrode.

[0117] Optionally, a difference between the thickness of the bus electrode and the thickness of the second collecting electrode is 3-6 μm.

[0118] Optionally, the segments of the first collecting electrode corresponding to the bus electrode are coated with an insulating adhesive layer;

[0119] The length of the insulating rubber layer is greater than or equal to the length of the bus electrode in the second direction;

[0120] The width of the insulating adhesive layer is ≥ the width of the first collecting electrode + 50 μm;

[0121] The second direction is parallel to the extending direction of the collecting electrode.

[0122] Optionally, for a third collecting electrode adjacent to the bus electrode, a segment of the third collecting electrode corresponding to the bus electrode is truncated; the truncation length is greater than or equal to the length of the bus electrode in the second direction;

[0123] Alternatively, the segment of the third collecting electrode corresponding to the bus electrode is coated with an insulating rubber layer; the length of the insulating rubber layer is ≥ the length of the bus electrode in the second direction; the second direction is parallel to the extension direction of the collecting electrode, and the polarity of the third collecting electrode is different from the polarity of the first bus electrode.

[0124] Optionally, the busbar is arranged in the middle and / or at both ends of the photovoltaic module.

[0125] The above content can refer to the relevant description in the above photovoltaic component embodiment, which will not be repeated here.

[0126] In summary, the embodiment of the present invention sets the distance between the bus electrode and the corresponding first collecting electrode so that when the interconnection parts are subsequently welded, there is a suitable buffer gap between the first collecting electrode and the corresponding bus electrode. Therefore, the stress generated on the first collecting electrode has a weakened effect on the bus electrode, thereby reducing the probability of hidden cracks in the battery cell during the lap welding and subsequent lamination processes, and improving the battery quality.

[0127] The terms "first," "second," and the like in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, such that embodiments of the present invention can be implemented in orders other than those illustrated or described herein. Furthermore, the objects distinguished by "first," "second," and the like generally refer to a class of objects and do not limit the number of objects. For example, the first object may be one or more.

[0128] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the scope of protection of the present invention.

Claims

1. A photovoltaic module, characterized in that: The photovoltaic module comprises: at least two battery strings and at least one bus bar; The battery string includes: at least two battery cells and an interconnector; adjacent battery cells are electrically connected via the interconnector; the bus bar is electrically connected to at least two battery strings; the battery cell includes a first surface and a second surface, electrodes are provided on the first surface, and the electrodes include: a collector electrode and a bus electrode; A first battery cell adjacent to the bus bar, a distance s between a first bus electrode adjacent to a first side in the first battery cell and a first collecting electrode is ≥ 230 μm-d, where d is a thickness of the first battery cell, and the first side is an edge of the first battery cell close to the bus bar; the first collecting electrode is a collecting electrode adjacent to the first bus electrode and having the same polarity as the first bus electrode.

2. The photovoltaic module according to claim 1, wherein The distance s is ≤ 430 μm-d.

3. The photovoltaic module according to claim 1, wherein: 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

4. The photovoltaic module according to claim 1, wherein: A ratio of a width of the first collecting electrode in the first direction to a width of the first bus electrode in the first direction is 0.008-0.064; The first direction is perpendicular to the extending direction of the collecting electrode.

5. The photovoltaic module according to claim 1, wherein: For the second collecting electrode overlapping with the first bus electrode, along the first direction, the width of the first bus electrode is w, and the distance between the second collecting electrode and the side of the first bus electrode is L; 0.08×w≤L≤0.5×w; The first direction is perpendicular to the extending direction of the collecting electrode, and the second collecting electrode has the same polarity as the first bus electrode.

6. The photovoltaic module according to claim 5, wherein: The difference between the thickness of the first bus electrode and the thickness of the second collecting electrode is 3-6 μm.

7. The photovoltaic module according to any one of claims 1 to 6, characterized in that: The segments of the first collecting electrode corresponding to the first bus electrode are coated with an insulating rubber layer; the first collecting electrode collects current to the first bus electrode through a connecting wire; The length of the insulating rubber layer is greater than or equal to the length of the first bus electrode in the second direction; The width of the insulating adhesive layer is ≥ the width of the first collecting electrode + 50 μm; The second direction is parallel to the extending direction of the collecting electrode.

8. The photovoltaic module according to any one of claims 1 to 6, characterized in that: For the third collecting electrode adjacent to the first bus electrode, the segment of the third collecting electrode corresponding to the first bus electrode is truncated; the length of the truncation is ≥ the length of the first bus electrode in the second direction; the polarity of the third collecting electrode is different from the polarity of the first bus electrode, and the second direction is parallel to the extension direction of the collecting electrode.

9. The photovoltaic module according to any one of claims 1 to 6, characterized in that: The busbars are arranged at the middle position and / or at both ends of the photovoltaic assembly.

10. A battery cell, characterized in that: The battery cell comprises a first surface and a second surface, wherein electrodes are provided on the first surface, and the electrodes comprise: a collecting electrode and a bus electrode; The busbar electrode and the first collecting electrode are spaced apart by a distance s; the distance s is ≥ 230 μm-d, where d is the thickness of the battery cell. The first collecting electrode is adjacent to the busbar electrode and has the same polarity as the busbar electrode.

11. The battery cell according to claim 10, wherein: The distance s is ≤ 430 μm-d.

12. The battery cell according to claim 10, wherein: 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

13. The battery cell according to claim 10, wherein: A ratio of a width of the first collecting electrode in the first direction to a width of the bus electrode in the first direction is 0.008-0.064; The first direction is perpendicular to the extending direction of the collecting electrode.

14. The battery cell according to claim 10, wherein: For the second collecting electrode overlapping with the bus electrode, along the first direction, the width of the bus electrode is w, and the distance between the second collecting electrode and the side of the bus electrode is L; 0.08×w≤L≤0.5×w; The first direction is perpendicular to the extending direction of the collecting electrode, and the second collecting electrode has the same polarity as the bus electrode.

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