Photovoltaic module and battery piece

Abstract

The invention provides a photovoltaic module and a battery piece. The photovoltaic module comprises at least two battery strings and at least one bus bar, the battery string comprises at least two battery pieces and an interconnection piece; the adjacent battery pieces are electrically connected through an interconnection piece; the bus bar is electrically connected with the at least two battery strings; the first surface of the battery piece is provided with electrodes, and the electrodes comprise a current collection electrode and a bus electrode; for the first battery piece adjacent to the bus bar, the distance between a first bus electrode adjacent to the first side edge in the first battery piece and a first current collection electrode is greater than or equal to 230 [mu] m-d, d is the thickness of the first battery piece, and the first side edge is the side edge, close to the bus bar, in the first battery piece; the first collector electrode is adjacent to the first bus electrode and has the same polarity as the first bus electrode. According to the invention, the probability of hidden cracks of the first battery piece at the position close to the bus bar in stitch welding and subsequent lamination processes is reduced, so that the battery quality is improved.

Description

Technical Field

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

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

[0003] A cell string usually refers to connecting multiple solar cells in series to form an electrical connection. In a series connection, the positive electrode of each solar cell is electrically connected to the negative electrode of the next cell through an interconnect.

[0004] During the preparation process of a photovoltaic module, the welding operation is a key process step. However, this process inevitably involves high-temperature heat treatment. Due to the difference in the coefficient of thermal expansion between the interconnect and the silicon wafer material of the solar cell, it will be significantly affected by the "thermal expansion and contraction" effect after welding. Specifically, stress differences are generated between the interconnect and the cell, which in turn causes obvious warping of the solar cell. The warped cells will be subjected to extrusion stress during automatic sheet laying or lamination, increasing the breakage rate of the solar cells. Under the action of high temperature and high pressure in the lamination process, the stress is further concentrated, which may cause the cells to have hidden cracks, thereby weakening the power generation performance of the module. Summary of the Invention

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

[0006] To solve the above problems, the present invention is implemented as follows: In a first aspect, an embodiment of the present invention provides a photovoltaic module, including: At least two cell strings and at least one bus bar; The cell string includes: at least two cells and an interconnect; adjacent cells are electrically connected through the interconnect; the bus bar is electrically connected to at least two of the cell strings; the cell includes a first surface and a second surface, and an electrode is provided on the first surface, and the electrode includes: a current collecting electrode and a bus bar 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.

[0007] Optionally, the distance s≤430 μm-d.

[0008] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0009] 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; The first direction is perpendicular to the extending direction of the collecting electrode.

[0010] 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; 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 and the first bus electrode have the same polarity.

[0011] Optionally, a difference between the thickness of the first bus electrode and the thickness of the second collecting electrode is 3-6 μm.

[0012] 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; 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.

[0013] Optionally, 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.

[0014] Optionally, the bus bar is disposed at the middle position and / or both end positions of the photovoltaic module.

[0015] In a second aspect, an embodiment of the present invention provides a cell, which includes a first surface and a second surface, and an electrode is disposed on the first surface, and the electrode includes: a current collecting electrode and a bus bar electrode; There is a distance s between the bus bar electrode and the first current collecting electrode; the distance s ≥ 230 μm - d, where d is the thickness of the first cell, and the first current collecting electrode is the current collecting electrode adjacent to the bus bar electrode and having the same polarity as the bus bar electrode.

[0016] Optionally, the distance s ≤ 430 μm - d.

[0017] Optionally, 100 μm ≤ s ≤ 300 μm; 60 μm ≤ d ≤ 150 μm; 2d / 3 ≤ s ≤ 5d.

[0018] Optionally, the ratio of the width of the first current collecting electrode in the first direction to the width of the bus bar electrode in the first direction is 0.008 - 0.064; The first direction is perpendicular to the extending direction of the current collecting electrode.

[0019] Optionally, for a second current collecting electrode overlapping with the bus bar electrode, along the first direction, the width of the bus bar electrode is w, and the distance between the second current collecting electrode and the side of the bus bar electrode is L; 0.08×w ≤ L ≤ 0.5×w; The first direction is perpendicular to the extending direction of the current collecting electrode, and the second current collecting electrode has the same polarity as the bus bar electrode.

[0020] An embodiment of the present invention can set the distance s between the first bus bar electrode and the first current collecting electrode. By setting the distance s, a suitable buffer interval can be provided between the first current collecting electrode and the first bus bar electrode. Therefore, the influence of the stress generated on the first current collecting electrode on the first bus bar electrode is weakened. Also, since the first bus bar electrode is at the end position of the cell where the bus bar is arranged, that is, the stress concentration at the position close to the bus bar in the first cell at the head and tail of the cell string is reduced, thereby reducing the probability of hidden cracks occurring at the position close to the bus bar in the first cell during the overlapping soldering and subsequent lamination processes, and improving the cell quality. Description of the Drawings

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0022] Figure 1 Schematic diagram of the layout structure of a photovoltaic module according to an embodiment of the present invention; Figure 2 Schematic diagram of the appearance structure of a solar cell according to an embodiment of the present invention; Figure 3 Schematic diagram of the partial structure of a solar cell according to an embodiment of the present invention; Figure 4 Schematic diagram of the partial structure of another solar cell according to an embodiment of the present invention; Figure 5 Schematic diagram of the partial structure of another solar cell according to an embodiment of the present invention; Figure 6 Schematic diagram of the enlarged partial structure of a solar cell according to an embodiment of the present invention; Figure 7 Schematic diagram of the division of measurement points of a solar cell according to an embodiment of the present invention; Figure 8 Schematic diagram of the structure of a busbar electrode and a current collector electrode according to an embodiment of the present invention; Figure 9 Schematic diagram of the structure of another busbar electrode and current collector electrode according to an embodiment of the present invention.

[0023] Reference numerals: 10 - battery string; 11 - solar cell; 111 - first solar cell; 20 - busbar; 30 - electrode; 31 - current collector electrode; 311 - first-polarity current collector electrode; 312 - second-polarity current collector electrode; 311a - first current collector electrode; 311b - second current collector electrode; 311c - third current collector electrode; 32 - busbar electrode; 321 - first busbar electrode; 322 - second-polarity busbar electrode; 321a - fourth busbar electrode; 40 - insulating adhesive layer; 41 - connecting wire; 50 - interconnector; 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 implementation manners

[0024] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be fully conveyed to those skilled in the art.

[0025] As Figure 1 shown, the present invention provides a photovoltaic module, comprising: at least two cell strings 10, and at least one bus bar 20; the cell string 10 comprises: at least two cells 11 and an interconnecting member 50; adjacent cells 11 are electrically connected by the interconnecting member 50; the bus bar 20 is electrically connected to at least two cell strings 10; further referring to Figure 2 and Figure 3 , the cell 11 comprises a first surface B and a second surface, and an electrode 30 is disposed on the first surface B, and the electrode 30 comprises: a current collecting electrode 31 and a bus bar electrode 32; for the first cell 111 adjacent to the bus bar 20 (i.e., the cell in the first region A), further referring to Figure 4 , the distance s between the first bus bar electrode 321 adjacent to the first side A1 in the first cell 111 and the first current collecting electrode 311a is s≥230μm - d, where d is the thickness of the first cell; the first side A1 is the side of the first cell 111 close to the bus bar 20; the first current collecting electrode 311a is the current collecting electrode 31 adjacent to the first bus bar electrode 321 and having the same polarity as the first bus bar electrode 321.

[0026] In the embodiments of the present invention, the photovoltaic module is a module formed by electrically connecting a plurality of solar cells. First, referring to Figure 1 , the cell string 10 is a series-connected structure formed by sequentially connecting a plurality of cells 11 ( Figure 1 shows that one cell string 10 includes 10 cells 11), and adjacent cell strings 10 are interconnected by the bus bar 20 to form a cell string group C, and two cell string groups C ( Figure 1 shows that the battery structure includes 6 cell string groups and 12 cell strings 10) are further connected in parallel to form the battery structure of the photovoltaic module. In addition, during the preparation of the photovoltaic module, operations such as welding and lamination of the interconnecting member 50 and the bus bar electrode 32 are also required. Among them, the bus bar 20 is usually disposed at both ends and / or in the middle of the photovoltaic module. For example, Figure 1 , after a plurality of cell string groups C are connected in parallel, the bus bar 20 is usually disposed on the same side of a plurality of juxtaposed cell string groups C, and / or disposed at a position close to the same side of a plurality of juxtaposed cell string groups C. Among them, the interconnecting member 50 can be in the form of a welding tape, including a welding tape with a tin-containing layer, an alloy welding tape, a welding tape without a tin layer, etc.

[0027] In some examples, referring to Figure 1 , a bypass diode can be reversely connected in parallel to each battery string group C, which can ensure that when the solar cells in the battery string group C are shaded, through the action of the bypass diode, it can at least not affect the solar cells outside the shaded battery string group C, thereby effectively preventing the hot spot effect.

[0028] In some examples, referring to Figure 4 , the first current collecting electrode 311a adjacent to the first bus electrode 321 can be located above the first bus electrode 321.

[0029] In other examples, referring to Figure 5 , the first current collecting electrode 311a adjacent to the first bus electrode 321 can be located below the first bus electrode 321.

[0030] In other examples, referring to Figure 6 , the first current collecting electrode 311a adjacent to the first bus electrode 321 can include a first current collecting electrode 311a located above the first bus electrode 321 and a first current collecting electrode 311a located below the first bus electrode 321.

[0031] The solar cells in the photovoltaic module according to the embodiment of the present invention can be back contact solar cells. Referring to Figure 2 and Figure 3 , the electrode 30 is disposed on the first surface B (backlight surface) of the solar cell 11. The electrode 30 includes a current collecting electrode 31 and a bus electrode 32. The current collecting 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 the first direction X, and the current collecting electrode can extend along the second direction Y. The first direction X is perpendicular to the second direction Y.

[0032] Among them, the current collecting electrode 31 can generally be a fine grid line. In one case, the bus electrode 32 can include pads and main grids arranged and extending along the first direction X; in another case, the bus electrode 32 can only include pads arranged and extending along the first direction X (without a main grid structure). For these two cases, the pads can include a first bus electrode 321 disposed at a position close to the bus bar 20 in the solar cell 11, and a plurality of fourth bus electrodes 321a disposed at a position close to the middle of the solar cell 11. The size of the first bus electrode 321 can be greater than or equal to or less than the size of the fourth bus electrode 321a. Among them, the size can be length, width, area, etc.

[0033] Taking the example that the size of the first current collecting electrode 321 is larger than that of the fourth current collecting electrode 321a, it can be that the width of the first current collecting electrode 321 is larger than that of the fourth current collecting electrode 321a, or the length of the first current collecting electrode 321 is larger than that of the fourth current collecting electrode 321a, or both the length and width of the first current collecting electrode 321 are larger than the length and width of the fourth current collecting electrode 321a.

[0034] The pad can also include a large-sized pad disposed at a position of the cell 11 close to the bus bar 20, and a plurality of welding areas disposed at a position of the cell 11 close to the middle position. A thickening section can be arranged on the current collecting electrode (a partial area or all areas in the thickening section can be thicker than the current collecting electrode, and the shape of the thickening section is a straight shape or an I-shaped), or there is only a fine grid, and the solder tape is welded on the fine grid. The pad (i.e., the current collecting electrode 32) contains tin and silver, and the pad is used for welding with the interconnecting member. Since Figure 2 、 Figure 3 It is shown that the cell is a main-gridless cell, so there is no main-grid structure in the second region D, that is, the cell 11 plays a role of collecting and outputting current through a plurality of current collecting electrodes 32 (i.e., pads) arranged along the first direction X.

[0035] In addition, the cell 11 can have two different polarities, namely a first polarity and a second polarity. For example, the first polarity is the positive electrode and the second polarity is the negative electrode, or the first polarity is the negative electrode and the second polarity is the positive electrode. According to the polarity division, the current collecting electrode 31 can include a first-polarity current collecting electrode 311 ( Figure 3 thick solid line in the figure) and a second-polarity current collecting electrode 312 ( Figure 3 thin dotted line in the figure). Along the first direction X, the first-polarity current collecting electrode 311 and the second-polarity current collecting electrode 312 are arranged alternately; the current collecting electrode 32 can include a first-polarity current collecting electrode and a second-polarity current collecting electrode 322; along the second direction Y, the first-polarity current collecting electrode and the second-polarity current collecting electrode 322 are arranged alternately. The first-polarity current collecting electrode is used to conduct with the first-polarity current collecting electrode 311, and the second-polarity current collecting electrode 322 is used to conduct with the second-polarity current collecting electrode 312. As shown in Figure 3 the figure, on the left is a column of first-polarity current collecting electrodes, in the middle is a column of second-polarity current collecting electrodes 322, and on the right is a column of first-polarity current collecting electrodes; starting from the first side A1 of the cell 11 along the first direction X, the first row is the second-polarity current collecting electrode 312, the second row is the first-polarity current collecting electrode 311, the third row is the second-polarity current collecting electrode 312... Furthermore, referring to Figure 3 , for a column of current collecting electrodes of the same polarity, among them, a first current collecting electrode 321 close to the first side A1 has a larger size, while a plurality of fourth current collecting electrodes 321a far from the first side A1 have a smaller size.

[0036] During the high-temperature heating process of soldering back-contact solar cells, due to the different coefficients of thermal expansion between the interconnecting components and the silicon wafers, after soldering, the cells are subject to thermal expansion and contraction, which will cause the cells to warp. And since the positive and negative electrodes of the back-contact solar cells are both on the back of the cells, the warpage degree is 3-5 mm higher than that of double-sided interconnected solar cells. Double-sided interconnected solar cells such as tunnel oxide passivated contact (TOPCon) cells. The front side of TOPCon cells has the same structure as that of conventional N-type solar cells. The main difference is that a thin layer of silicon oxide is prepared on the back of the cell, and then a doped silicon thin layer is deposited. The two together form a passivated contact structure, effectively reducing surface recombination and metal contact recombination.

[0037] For back-contact solar cells, the cells at the head and tail of the cell string have no force from other cells at one end, which will make the warpage degree of the cells at the head and tail larger than that of the cells in the middle. In the processes of string soldering and subsequent lamination, due to the increased warpage degree of the cells at the head and tail, the proportion of hidden cracks and broken pieces at this position is relatively high, accounting for 70%-80% of the total hidden cracks and broken pieces.

[0038] In addition, when decomposing the positions of the hidden cracks in the cells at the head and tail, 90% of them are concentrated at the busbar electrode positions near the end edges of the cells at the head and tail. Therefore, the embodiments of the present invention need to analyze the morphology of the busbar electrode positions near the end edges of the cells at the head and tail to solve the hidden crack problem here.

[0039] In the related art, in order to collect current, the current collector electrode near the busbar electrode passes through or is adjacent to the busbar electrode, and the adjacent distance between the two is random. The related art does not stipulate the specific range of this distance. Thus, during the process of interconnecting the cells through the interconnecting components, the tin on the solder tape is not wetted to the surface of the cell not covered by the electrodes. Since the silver content in the material of the busbar electrode is relatively high (generally 60%-80%), and the silver content of the current collector electrode is even higher (generally above 90%), the tin on the device with a low silver content will migrate towards the device with a high silver content. Therefore, when the distance between the first busbar electrode and the first current collector electrode is very close, or the first current collector electrode passes through the first busbar electrode, the tin on the first busbar electrode (large-size pad) and / or the tin on the interconnecting component will flow and accumulate on the first current collector grid line, increasing the stress at the first current collector electrode. This results in a relatively high probability of hidden cracks in the cells during string soldering and subsequent lamination processes. After the cells are cracked and broken, the photoelectric conversion efficiency of the cells drops severely, thus affecting the cell quality.

[0040] To solve this problem, referring to Figure 1-4 In the embodiments of the present invention, for the first cell 111 adjacent to the busbar 20 ( Figure 1The solar cells in area A are processed, and the improvement is specifically focused on the position of the first bus electrode 321 adjacent to the first side A1 in the first solar cell 111. Among them, the first solar cell 111 is located at the head and tail of the solar cell string 10. The warpage of these solar cells is greater than that of the solar cells at other positions, and it is more likely to generate hidden cracks. Further, the position of the first bus electrode 321 adjacent to the first side A1 in the first solar cell 111 is the high-incidence position of the hidden crack phenomenon.

[0041] In the embodiment of the present invention, a distance s can be set between the first bus electrode 321 and the first current collecting electrode 311a. Among them, the first current collecting electrode 311a is a current 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 current collecting electrode 311a, a suitable buffer interval can be provided between the first current collecting electrode 311a and the first bus electrode 321, and the above-mentioned adverse effects can be avoided. Through the setting of the distance s, a suitable buffer interval can be provided between the first current collecting electrode and the first bus electrode. Therefore, the stress generated on the first current collecting electrode has a weakened impact on the first bus electrode. Also, since the first bus electrode is located at the end position of the bus bar in the solar cell, that is, the stress concentration at the position close to the bus bar in the first solar cell at the head and tail of the solar cell string is reduced, thereby reducing the probability of hidden cracks occurring at the position close to the bus bar in the first solar cell during the stacking welding and subsequent lamination processes, and improving the battery quality.

[0042] It should be noted that referring to Figure 4 , the distance s refers to the vertical distance between the side of the first current 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 current collecting electrode 311a.

[0043] In summary, in the embodiment of the present invention, the distance s between the first bus electrode and the first current collecting electrode can be set. Through the setting of the distance s, a suitable buffer interval can be provided between the first current collecting electrode and the first bus electrode. Therefore, the stress generated on the first current collecting electrode has a weakened impact on the first bus electrode. Also, since the first bus electrode is located at the end position of the bus bar in the solar cell, that is, the stress concentration at the position close to the bus bar in the first solar cell at the head and tail of the solar cell string is reduced, thereby reducing the probability of hidden cracks occurring at the position close to the bus bar in the first solar cell during the stacking welding and subsequent lamination processes, and improving the battery quality.

[0044] In the embodiment of the present invention, for the measurement of the thickness of the solar cell, the following method can be adopted: Preparation: The surveyors shall wear anti-static clothes and nitrile gloves.

[0045] Equipment to be used: A height gauge that is calibrated and within the calibration validity period, and the measurement accuracy of the height gauge is not less than 1um.

[0046] Measurement steps: 1. Query the sampling quantity according to the sampling characterization against the sampling table, randomly select the corresponding number of solar cells to be measured, and handle the solar cells gently to avoid damage when picking and placing them.

[0047] 2. Zero the height gauge at the platform position, pick up the solar cells in sequence (with the adhesive side of the solar cell facing up), and measure the thicknesses of the measurement points 1, 2, 3, 4, and 5 in sequence according to the measurement point requirements in Figure 7 while avoiding the adhesive position, and record the measurement data.

[0048] 3. Repeat step 2 to complete the thickness measurement of other sampled solar cells.

[0049] 4. Calculate the average value of the thickness values of the measurement points 1, 2, 3, 4, and 5 recorded as the value of d.

[0050] Optionally, the distance s≥230μm - d, with the unit being micrometers for all.

[0051] Optionally, the distance s≤430μm - d, with the unit being micrometers for all.

[0052] Combined with the above limitations, 230μm - d≤distance s≤430μm - d. In the embodiments of the present invention, the distance s can solve the problem of fragmentation of the solar cells near the bus bar in the photovoltaic module. However, the distance s cannot be too large. If the distance s is too large (exceeding the upper limit value of its range), it will cause the arrangement of the current collecting electrodes to be too sparse, the distance between the same-polarity current collecting electrodes to be too large, the carrier transmission distance to be too long, and the carriers to be easily recombined during transmission, which is not conducive to the current collection of the solar cells 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 become smaller, resulting in insufficient welding drawing force of the first bus electrode and affecting the overall reliability. Therefore, the distance s cannot be too large.

[0053] For example, if the thickness d of the first solar cell is 100μm, then 130μm≤distance s≤330μm.

[0054] Optionally, 100μm≤s≤300μm; 60μm≤d≤150μm; 2d / 3≤s≤5d.

[0055] In the embodiment of the present invention, the set range for the thickness d of the first battery cell is 60 μm - 150 μm; the set range for the distance s can be 100 μm - 300 μm; by analyzing based on the upper and lower limits of the range, the relationship between the distance s and the thickness d can be obtained: 2d / 3 ≤ s ≤ 5d.

[0056] In the embodiment of the present invention, the battery cells used in the photovoltaic module can be selected first, and then the distance s can be determined according to the thickness of the battery cells. Among them, the thinner the first battery cell, the lower the cost, but the thickness of the first battery cell cannot be too small, because too small a thickness will affect the light absorption effect of the first battery cell and make the first battery cell fragile, thus affecting the optical and mechanical properties of the first battery cell. When the thickness of the first battery cell is larger, the mechanical strength of the first battery cell is better, and the required distance s is smaller; when the thickness of the first battery cell is smaller, the mechanical strength of the first battery cell is weaker, and the required distance s is larger. Among them, the mechanical strength of the first battery cell can be reflected in its bending resistance and compressive resistance. The larger the thickness of the first battery cell, the better its bending resistance and compressive resistance performance.

[0057] Optionally, referring to Figure 4 , the ratio of the width of the first current collecting electrode 311a in the first direction X to the width of the first busbar 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 current collecting electrode.

[0058] In the embodiment of the present invention, the ratio of the width of the first current collecting electrode 311a in the first direction X to the width w of the first busbar electrode 321 in the first direction X is 0.008 - 0.064, and this ratio can be 0.048 for example.

[0059] Among them, the width range of the first current collecting electrode in the first direction X is 0.01 mm - 0.08 mm. This width range can make the first current collecting electrode relatively narrow, thus reducing the shading interference to the battery cell during illumination, and thus improving the optical performance of the battery cell.

[0060] The width of the first busbar electrode in the first direction X is 1.25 mm. The relatively wide width of the first busbar electrode in the first direction X enables the first busbar electrode to have a larger contact area with the solder tape, improving the connection performance. In addition, the relatively large width of the first busbar electrode in the first direction X makes the area of the first busbar electrode relatively large. When the area of the first busbar electrode is relatively large, the thickness of the first busbar electrode can be relatively small, thus saving material costs.

[0061] The calculation process of the upper and lower boundary values of the range where the ratio is located is as follows: The ratio of the minimum width of the first collector electrode in the first direction, which is 0.01 mm, to the width of the first busbar electrode in the first direction, which is 1.25 mm, is the lower boundary value of the range where the ratio is located, which is 0.008 mm; The ratio of the maximum width of the first collector electrode in the first direction, which is 0.08 mm, to the width of the first busbar electrode in the first direction, which is 1.25 mm, is the upper boundary value of the range where the ratio is located, which is 0.064 mm.

[0062] Among them, if the ratio is too large, more tin will accumulate on the first collector electrode, and the stress concentration at the first collector electrode will be more serious, resulting in a greater probability of subsequent cell cracking. Therefore, the ratio should be as small as possible. However, the ratio cannot be too small either. If the ratio is too small, the first collector electrode will be too thin, thus affecting the current transmission efficiency. Therefore, in the embodiment of the present invention, the ratio of the width of the first collector electrode 311a in the first direction X to the width of the first busbar electrode 321 in the first direction X is set to be in the range of 0.008 - 0.064, so as to not only ensure that the current transmission efficiency of the first collector electrode meets the requirements, but also reduce the stress concentration at the first collector electrode and reduce the probability of subsequent cell cracking.

[0063] Optionally, referring to Figure 4 , for the second collector electrode 311b overlapping with the first busbar electrode 321, along the first direction X, the width of the first busbar electrode is w, and the distance between the second collector electrode 311b and the side of the first busbar electrode 321 is L.

[0064] 0.08×w ≤ L ≤ 0.5×w; The first direction X is perpendicular to the extending direction Y of the collector electrode, and the second collector electrode 311b has the same polarity as the first busbar electrode 321.

[0065] In the embodiment of the present invention, for the second collector electrode 311b with the same polarity overlapping with the first busbar electrode 321, the distance L between the second collector electrode 311b and the side of the first busbar electrode 321 has the following relationship with the width w of the first busbar electrode: 0.08×w ≤ L ≤ 0.5×w; This can make a certain safety distance as a buffer between the second collector electrode 311b and the side of the first busbar electrode 321, so that when welding the interconnector later, the phenomenon of tin on the interconnector aggregating towards the silver on the second collector electrode is weakened, thereby reducing the stress concentration on the second collector electrode, and further reducing the probability of cell cracking in the stacking welding and subsequent lamination processes, and improving the cell quality.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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 .

[0070] 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; The width w1 of the insulating adhesive layer is ≥ the width of the first collecting electrode + 50 μm; The second direction Y is parallel to the extending direction of the collecting electrodes.

[0071] 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.

[0072] Optional, see Figure 9, for the third current collector electrode 311c adjacent to the first bus electrode 321, a truncation process is performed on the segment C1 of the third current collector electrode 311c corresponding to the first bus electrode 321; the truncated length L2 ≥ the length h of the first bus electrode 321 in the second direction Y; the polarity of the third current collector electrode 311c is different from that of the first bus electrode 321.

[0073] In an embodiment of the present invention, in one implementation, the third current collector electrode 311c with a different polarity adjacent to the first bus electrode 321 can be truncated at the segment C1 corresponding to the first bus electrode 321, thereby avoiding short - circuit caused by the connection of the adjacent third current collector electrodes 311c with different polarities to the first bus electrode 321.

[0074] Optionally, referring to Figure 1 , the bus bar 20 is disposed at the middle position and / or both ends of the photovoltaic module.

[0075] The bus bar 20 is usually disposed at both ends and / or the middle position of the photovoltaic module. For example, Figure 1 , that is, after multiple battery string groups are connected in parallel, the bus bar 20 is usually disposed on the same side of multiple side - by - side arranged battery string groups, and / or disposed at a position close to the same side of multiple side - by - side arranged battery string groups.

[0076] In summary, in the embodiment of the present invention, the distance s between the first bus electrode and the first current collector electrode can be set. By setting the distance s, a suitable buffer interval can be provided between the first current collector electrode and the first bus electrode. Therefore, the influence of the stress generated on the first current collector electrode on the first bus electrode is weakened. Also, since the first bus electrode is at the end position of the battery cell where the bus bar is arranged, that is, 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 appearing at the position close to the bus bar in the first battery cell during the stacking welding and subsequent lamination processes, and improving the battery quality.

[0077] Referring to Figures 2-4 , an embodiment of the present invention provides a battery cell. The battery cell 11 includes a first surface and a second surface. Electrodes 30 are disposed on the first surface. The electrodes 30 include: a current collector electrode 31 and a bus electrode 32; the distance s between the bus electrode 32 and the first current collector electrode 311a ≥ 230μm - d, where d is the thickness of the first battery cell, and the first current collector electrode 311a is a current collector electrode adjacent to the bus electrode 32 and having the same polarity as the bus electrode 32.

[0078] Among them, the battery cell 11 can be any battery cell in the photovoltaic module, and the bus electrode 32 can be any bus electrode among all the bus electrodes 32 included in the battery cell 11.

[0079] In an embodiment of the present invention, a distance s can be set between the bus electrode 32 and its corresponding first current collecting electrode 311a. Here, the first current collecting electrode 311a is a current collecting electrode adjacent to the bus electrode 32 and having the same polarity as the bus electrode 32. By setting the distance s between the bus electrode 32 and the corresponding first current collecting electrode 311a, a suitable buffer interval can be provided between the first current collecting electrode and the corresponding bus electrode. Therefore, the influence of the stress generated on the first current collecting electrode on the bus electrode is weakened, thereby reducing the probability of the cell sheet cracking in the stacking welding and subsequent lamination processes and improving the cell quality.

[0080] Optionally, s ≤ 430μm - d.

[0081] Optionally, 100μm ≤ s ≤ 300μm; 60μm ≤ d ≤ 150μm; 2d / 3 ≤ s ≤ 5d.

[0082] Optionally, the ratio of the width of the first current collecting electrode in the first direction to the 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 current collecting electrode.

[0083] Optionally, for a second current 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 current 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 current collecting electrode, and the second current collecting electrode has the same polarity as the bus electrode.

[0084] Optionally, the difference between the thickness of the bus electrode and the thickness of the second current collecting electrode is 3 - 6μm.

[0085] Optionally, an insulating adhesive layer is segmentally coated on the first current collecting electrode corresponding to the bus electrode; The length of the insulating adhesive layer ≥ the length of the bus electrode in the second direction; The width of the insulating adhesive layer ≥ the width of the first current collecting electrode + 50μm; The second direction is parallel to the extending direction of the current collecting electrode.

[0086] Optionally, for a third current collecting electrode adjacent to the bus electrode, the segment of the third current collecting electrode corresponding to the bus electrode is truncated; the truncated length ≥ the length of the bus electrode in the second direction; Alternatively, an insulating adhesive layer is segmentally coated on the third current collecting electrode corresponding to the busbar electrode; the length of the insulating adhesive layer is ≥ the length of the busbar electrode in the second direction; the second direction is parallel to the extending direction of the current collecting electrode, and the polarity of the third current collecting electrode is different from that of the first busbar electrode.

[0087] Optionally, the busbar is disposed at the middle position and / or both end positions of the photovoltaic module.

[0088] The above content may refer to the relevant descriptions in the embodiments of the above photovoltaic module, and will not be elaborated here.

[0089] In summary, in the embodiment of the present invention, by setting the distance between the busbar electrode and the corresponding first current collecting electrode, when the interconnector is welded subsequently, a suitable buffer interval is provided between the first current collecting electrode and the corresponding busbar electrode. Therefore, the influence of the stress generated on the first current collecting electrode on the busbar electrode is weakened, thereby reducing the probability of the cell sheet cracking during the stack welding and subsequent lamination processes, and improving the cell quality.

[0090] The terms "first", "second", etc. in the description and claims of the present invention are used to distinguish similar objects, rather than to describe a specific order or sequence. It should be understood that such data may be interchanged under appropriate circumstances, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are usually of the same category, and the number of objects is not limited. For example, the first object may be one or more.

[0091] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "mounted", "connected", "coupled" shall be construed broadly. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal communication of two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0092] The above are only the preferred embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A photovoltaic module, characterized in that, The photovoltaic module includes: At least two cell strings and at least one bus bar; The cell string includes: at least two cells and interconnecting members; adjacent cells are electrically connected through the interconnecting members; the bus bar is electrically connected to at least two of the cell strings; the cell has a first surface and a second surface, and an electrode is provided on the first surface, and the electrode includes: a current collecting electrode and a bus electrode; For the first cell adjacent to the bus bar, the distance s between the first bus electrode and the first current collecting electrode adjacent to the first side edge in the first cell is s≥230μm - d, where d is the thickness of the first cell, and the first side edge is the side edge of the first cell close to the bus bar; the first current collecting electrode is a current 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≤430μm - d.

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

4. The photovoltaic module according to claim 1, wherein, The ratio of the width of the first current collecting electrode in the first direction to the 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 current collecting electrode.

5. The photovoltaic module according to claim 1, characterized in that, For the second current 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 current collecting electrode and the side edge 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 current collecting electrode, and the second current collecting electrode has the same polarity as the first bus electrode.

6. The photovoltaic module according to claim 5, characterized in that The difference in thickness between the first bus electrode and the second current collecting electrode is 3 - 6μm.

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

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

9. The photovoltaic module according to any one of claims 1 to 6, characterized in that The bus bar is arranged at the middle position and / or both end positions of the photovoltaic module.

10. A solar cell, characterized in that, The cell has a first surface and a second surface, and an electrode is provided on the first surface, and the electrode includes: a current collecting electrode and a bus electrode; There is a spacing distance s between the bus electrode and the first current collecting electrode; the distance s≥230μm - d, where d is the thickness of the cell, and the first current collecting electrode is a current collecting electrode adjacent to the bus electrode and having the same polarity as the bus electrode.

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

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

13. The solar cell according to claim 10, wherein The ratio of the width of the first current collecting electrode in the first direction to the width of the busbar electrode in the first direction is 0.008 - 0.064; The first direction is perpendicular to the extending direction of the current collecting electrode.

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

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