Photovoltaic module and photovoltaic module preparation method

Abstract

The invention discloses a photovoltaic module and a photovoltaic module preparation method, the photovoltaic module comprises a battery piece, a welding strip, a bus bar and an insulating block, and the back surface of the battery piece is provided with a fine gate electrode and a first insulating layer; the first welding strip is electrically connected with the fine gate electrode with the first polarity, and the second welding strip is electrically connected with the fine gate electrode with the second polarity; the insulating blocks are located on the back face of the battery piece, the insulating blocks and the first insulating layers are alternately arranged in the extending direction of the fine gate electrodes, and the insulating blocks cover part of the fine gate electrodes of the second polarity and part of the second welding strip; the first insulating layer covers part of the fine gate electrode with the second polarity; the bus bar is located in the area, corresponding to the first insulating layer and the insulating block, of the back face of the battery piece, the bus bar extends in the length direction of the fine grid electrode, the bus bar is electrically connected with the first welding strip, and the bus bar is electrically isolated from the second welding strip through the insulating block; and the bus bar is electrically isolated from the fine gate electrode with the second polarity through the insulating blocks and the first insulating layers which are alternately arranged.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a photovoltaic module and a method for preparing the photovoltaic module. Background Art

[0002] A photovoltaic module is composed of multiple cell strings, each of which is composed of multiple cells welded in series by welding ribbons. The welding ribbons on each cell string and between adjacent cell strings are usually conductively connected through bus bars.

[0003] In order to reduce the ineffective area occupied by the busbar in the photovoltaic module, the busbar is placed on the back of the battery cell. In this way, the busbar needs to be insulated from the electrodes on the battery cell and the welding strip with conductive properties opposite to the busbar. At present, the insulation structure of the busbar on the photovoltaic module is relatively complex, and the insulation stability needs to be further improved. Summary of the invention

[0004] The object of the present invention is to provide a photovoltaic module to simplify the insulation structure and improve the insulation stability.

[0005] In a first aspect, the present invention provides a photovoltaic module, comprising a cell, a welding strip, a bus bar and an insulating block, wherein the back of the cell has a fine grid electrode and a first insulating layer;

[0006] The first welding strip is electrically connected to the fine grid electrode of the first polarity, and the second welding strip is electrically connected to the fine grid electrode of the second polarity;

[0007] The insulating block is located on the back of the battery cell, the insulating block and the first insulating layer are alternately arranged along the extension direction of the fine gate electrode, the insulating block covers part of the fine gate electrode of the second polarity and part of the second welding strip; the first insulating layer covers part of the fine gate electrode of the second polarity;

[0008] The bus bar is located at the back of the battery cell in the area corresponding to the first insulating layer and the insulating block, and the bus bar extends along the length direction of the fine grid electrode;

[0009] The bus bar is electrically connected to the first welding strip, and the bus bar is electrically isolated from the second welding strip by an insulating block; the bus bar is electrically isolated from the fine grid electrode of the second polarity by the alternately arranged insulating blocks and the first insulating layer.

[0010] When the above technical solution is adopted, in the case of setting a bus bar on the back side of the battery cell, a first insulating layer and an insulating block are alternately arranged at the position corresponding to the bus bar on the back side of the battery cell along the extension direction of the fine gate electrode, the insulating block covers a portion of the fine gate electrode of the second polarity and a portion of the second welding strip, and the first insulating layer covers a portion of the fine gate electrode of the second polarity; the bus bar is electrically connected to the first welding strip, and the bus bar and the second welding strip are electrically isolated by the insulating block; the bus bar and the fine gate electrode of the second polarity are electrically isolated by the alternately arranged insulating blocks and the first insulating layer.

[0011] First, the present application can set the bus bar at any position on the back of the battery cell, extending along the length direction of the fine grid electrode. The location of the bus bar can be selected flexibly and diversely. It is only necessary to print the first insulating layer at the position corresponding to the bus bar and lay the insulating block to achieve electrical isolation from the fine grid electrode of the second polarity and the welding strip. The insulating block is set on the second welding strip, at the position where the bus bar is connected to the first welding strip, and the bus bar is insulated from the fine grid of the second polarity near the first welding strip by the first insulating layer, so that there is no barrier or pad between the bus bar and the first welding strip, and effective welding can be achieved relatively easily, reducing the problems of cold welding and difficulty in welding when there is an insulating block near the first welding strip.

[0012] In addition, based on the arrangement structure of the bus bars, welding strips, insulating blocks, etc. of the photovoltaic module on the back of the battery cell, a simpler layout and welding process can be selected. That is, after all the battery cells are laid on the front packaging cover, the welding strips, bus bars and insulating blocks are uniformly laid on the back of the battery cells and fixed together. Compared with the original method of first making the battery string, then arranging the battery string and welding the bus bars, it can simplify the process, reduce the process difficulty, improve the production efficiency of photovoltaic modules, and improve the module yield.

[0013] In some possible implementations, the projections of the insulating block and the first insulating layer on the battery cell are alternately connected, or the projections of the insulating block and the first insulating layer on the battery cell have an overlapping area at the connection. In this way, when the busbar is arranged in the area corresponding to the insulating block and the first insulating layer, the insulating block is connected or overlapped with the first insulating layer to avoid the formation of a gap between the insulating block and the first insulating layer in the length direction of the fine gate electrode, and the fine gate electrode of the second polarity is avoided from being exposed in the gap, which can better avoid the conductive contact between the busbar and the fine gate electrode of the second polarity below, prevent short circuit, and improve insulation performance.

[0014] In some possible implementations, along the length direction of the fine gate electrode, the length of the overlapping area between the insulating block and the projection of the first insulating layer on the cell sheet is greater than 0.5 mm. Since the edge of the insulating block is uneven and the thickness is relatively thin at some locations, the edge of the first insulating layer may be shorter or less thick. The insulating block overlaps the first insulating layer, and the length of the overlapping area is greater than 0.5 mm, which can avoid the degradation of the insulation performance of the edge of the first insulating layer and the insulating block.

[0015] In some possible implementations, the back of the battery cell also has a second insulating layer, the first insulating layer and the second insulating layer are arranged alternately along the length direction of the busbar, and the second insulating layer covers the fine grid electrode of the first polarity; the insulating block is stacked correspondingly on the second insulating layer. By setting the second insulating layer to cover the fine grid electrode of the first polarity, it is possible to avoid the second welding strip here from contacting the fine grid electrode of the first polarity below, thereby improving the insulation performance. At the same time, the second insulating layer only needs to be printed longer on the basis of the original insulating glue printed near the two sides of the second welding strip, without adding additional process steps. The superimposed insulating block can realize the placement of the busbar, and the busbar is electrically isolated from the second welding strip by the insulating block. The alternating arrangement of the first insulating layer and the second insulating layer improves the versatility of the battery cell, facilitates the use of busbars of different polarities, eliminates the need to select battery cells, and improves the preparation efficiency.

[0016] In some possible implementations, along the length direction of the busbar, the difference between the length of the first insulating layer and the length of the second insulating layer is less than or equal to 2 mm; and / or, along the width direction of the busbar, the difference between the width of the first insulating layer and the width of the second insulating layer is less than or equal to 2 mm. In this way, the length and / or width of the first insulating layer and the second insulating layer are similar, which improves the versatility of the battery cell, facilitates the use of busbars of different polarities, eliminates the need to select battery cells, and improves manufacturing efficiency.

[0017] And / or, along the width direction of the busbar, the first insulating layer and the second insulating layer are crossed; that is, the first insulating layer and the second insulating layer are alternately connected in the length direction of the busbar as a whole, and the printing patterns of the first insulating layer and the second insulating layer are simplified through repetitive arrangement, thereby improving the versatility of the first insulating layer and the second insulating layer, and facilitating the use of busbars of different polarities without the need to select battery cells, thereby improving preparation efficiency.

[0018] And / or, the first insulating layer and the second insulating layer are made of the same material and have the same thickness, and are printed on the battery cell simultaneously. In this way, the first insulating layer and the second insulating layer can be printed on the battery cell simultaneously in the same printing process, simplifying the preparation process and improving the preparation efficiency.

[0019] And / or, the first insulating layer and the second insulating layer are transparent adhesive layers. The first insulating layer and the second insulating layer are transparent adhesive layers, which can improve the light utilization rate of the battery cell.

[0020] In some possible implementations, the insulating block is a rectangular insulating block; in this way, the insulating block can be prevented from intruding between the bus bar and the first welding strip, reducing the risk of poor soldering between the bus bar and the first welding strip, while reducing the height difference caused by the insulating block and reducing the risk of hidden cracks.

[0021] Along the width direction of the bus bar, the width of the insulating block is 1 mm to 5 mm wider than the width of the bus bar.

[0022] Along the length direction of the bus bar, the length of the insulating block is 0.5 mm to 4 mm longer than the length of the second insulating layer stacked with the insulating block.

[0023] When adopting the above technical solution, the width of the insulating block can ensure the insulation effect between the bus bar and the second welding strip. The length of the insulating block is longer than the length of the second insulating layer stacked with it, so that there is an overlapping area between the edge of the insulating block and the adjacent first insulating layer, so as to avoid the appearance of a gap between the insulating block and the first insulating layer in the length direction of the fine gate electrode, and avoid the fine gate electrode of the second polarity from being exposed in the gap, which can better avoid the conductive contact between the bus bar and the fine gate electrode of the second polarity below, prevent short circuit, and improve insulation performance. In addition, the length and width of the insulating block will not be too large, thereby reducing shading and saving materials.

[0024] In some possible implementations, the pattern of the second insulating layer on all cells in the photovoltaic module is the same, and the pattern of the first insulating layer on all cells in the photovoltaic module is the same. In this way, during the production process, there is no need to distinguish between cells used to connect bus bars and cells not connected to bus bars, so that the versatility of all cells is improved, and there is no need to select cells with specific pattern insulating layers separately, which can greatly save processes and improve production efficiency.

[0025] In some possible implementations, in the length direction of the busbar, the end of the insulating region composed of the first insulating layer and the insulating block exceeds the end of the busbar by a distance of 1 mm to 5 mm;

[0026] In the width direction of the busbar, the side edge of the insulating area composed of the first insulating layer and the insulating block exceeds the side edge of the busbar by 1 mm to 5 mm;

[0027] Furthermore, in the thickness direction of the battery cell, the insulation distance between the bus bar and the second welding strip and the fine grid electrode of the second polarity is greater than or equal to 10 μm.

[0028] When the above technical solution is adopted, the size relationship between the insulating area and the busbar can not only meet the insulation requirements, but also save the material of the insulating area, and prevent the first insulating layer from being too large relative to the busbar and warping. The busbar is located in the insulating area to achieve a more reliable insulation effect between the busbar and the fine grid electrode of the second polarity and the second welding strip. The insulation distance between the busbar and the second welding strip and the fine grid electrode of the second polarity is greater than or equal to 10μm, which ensures reliable insulation between the busbar and the second welding strip and the fine grid electrode of the second polarity.

[0029] In some possible implementations, the insulating block is a tape, and the tape is pasted on the battery cell. By pasting it on the battery cell, compared with placing it directly on the battery cell, the insulating block and the battery cell can be pre-fixed, preventing the insulating block from shifting during the movement and lamination of the components, ensuring insulation reliability, and the tape is made of a flexible material, which can reduce the risk of fracturing the battery cell.

[0030] In some possible implementations, the busbar is located at a non-edge position of the battery cell; or, the busbar is located at the edge of the battery cell. In this case, when setting the busbar, it is not necessary to consider the positions of both battery cells at the same time in terms of the width of the busbar, and covering only one battery cell can avoid unbalanced load bearing due to the height difference between the two battery cells in the thickness direction, which can easily cause hidden cracks in the battery cell.

[0031] A bus bar covers part of the previous battery cell and part of the next battery cell; the bus bar covers a width of 1 mm to 5 mm on the previous battery cell, and a width of 1 mm to 5 mm on the next battery cell, and the spacing between the previous battery cell and the next battery cell is 0 to 2 mm.

[0032] When the above technical solution is adopted, the busbar can be located at the edge position or non-edge position of the back of the battery cell or cover parts of two adjacent battery cells at the same time, which expands the selection range of the busbar setting position on the back of the battery cell, facilitates the setting of the busbar, and can be set at a suitable position on the back of the battery cell according to the layout position of the battery cell in the photovoltaic module and the current transmission needs. The structure in this application can ensure reliable insulation between the busbar and the fine grid electrode of the second polarity and the second welding strip on the battery cell. When the busbar covers parts of two adjacent battery cells at the same time, it can be designed to be thin and wide to ensure the current transmission efficiency while avoiding hidden cracks in the battery cell caused by excessive thickness. At this time, the busbar can avoid the risk of hidden cracks or short circuits caused by excessive stress caused by being set on a certain battery cell, and can then play a role in dispersing the stress of busbar stacking and improve the yield of the component.

[0033] In some possible implementations, along the width direction of the busbar, the connection length between the busbar and a first welding strip is greater than or equal to 20% of the width of the busbar. In this way, the welding interconnection area between the first welding strip and the busbar is sufficient to meet the conductive transmission performance and welding reliability, and can reduce current loss.

[0034] In some possible implementations, the welding strips fixed on the busbars are aligned or connected on the busbars along the width direction of the busbars. Aligning the welding strips on the busbars can reduce the creepage distance difference of the components in the length direction of the busbars, reduce the side length of the photovoltaic components, and reduce the blank area of ​​the photovoltaic components. Connecting the welding strips on the busbars can reduce current losses.

[0035] In some possible implementations, the photovoltaic module further includes a buffer film located between the bus bar and the back packaging film of the photovoltaic module. The buffer film covers the bus bar, so that when the bus bar is under pressure, the buffer film buffers the location of the bus bar, thereby reducing the risk of hidden cracks in the battery cell.

[0036] In some possible implementations, the thickness of the buffer film is 200μm to 1000μm, and / or the width of the buffer film is 0 to 100mm wider than the width of the busbar, and / or the length of the buffer film is 0 to 5mm longer than the length of the busbar, and / or the material of the buffer film is POE, EPE or EVA. At this time, the selection of materials can ensure a good buffering effect on the busbar; the design of the thickness of the buffer film can take into account both the buffering effect and the stacking thickness, avoiding the problem of lamination bubbles caused by excessive thickness; the design of the width and length of the buffer film can ensure that the buffer film covers the entire busbar, reducing the problem of uneven local force.

[0037] In some possible implementations, the bus bar is located on the side of the first welding strip and the second welding strip away from the battery cell, and the height difference between the position of the bus bar corresponding to the first welding strip and the position of the bus bar corresponding to the second welding strip is less than or equal to 100 mm; and the cross-section of the welding strip is rectangular. The bus bars are all located above the welding strips, which can avoid bending of the welding strips when the bus bars are located below, reducing the risk of hidden cracks. The height difference between the positions of the corresponding two polarity welding strips will not be too large, which can avoid the battery cell from being hidden cracked due to uneven force on the battery cell due to excessive height difference. The welding strip is a flat welding strip, which can increase the contact area with the battery cell and reduce the pressure. When the welding strip is under pressure, the risk of hidden cracks on the battery cell can be reduced.

[0038] In some possible implementations, the distance between the cover plate and the back plate of the photovoltaic module is A, the sum of the thickness of the battery cell, the fine grid electrode and the welding strip is B, and B is less than 79% of A. The sum of the thickness of the battery cell, the fine grid electrode and the welding strip is less than 79% of the distance between the cover plate and the back plate, which can provide sufficient thickness space for the adhesive film layer with buffering and fixing effects, improve the buffering and fixing effects, and reduce the risk of hidden cracks in the battery cell.

[0039] In some possible implementations, the photovoltaic module includes m rows of cells, and a row of cells includes more than two cell strings; the spacing between adjacent cells in a row of cells is 0 to 2 mm, or the multiple cells in the cell string are arranged in a shingled pattern, and the width of the overlapping area of ​​adjacent cells in each cell string is 0.3 mm to 2 mm. The spacing between cells and strings of this type of photovoltaic module is reduced, which can increase the unit power of the photovoltaic module.

[0040] In some possible implementations, the difference in the minimum distance between the battery group composed of each battery cell in the photovoltaic module and each edge of the cover of the photovoltaic module is less than 0.5 mm. In this way, the difference in the distance between the battery group and the corresponding edge of the cover is small, which can reduce the side length of the photovoltaic module and increase the unit power of the photovoltaic module.

[0041] In some possible implementations, the thickness of the packaging film of the photovoltaic module at the position corresponding to the bus bar is less than the thickness of the packaging film at other positions. In this way, the force on the battery cell can be uniform, reducing the risk of hidden cracks in the battery cell. And / or, in the thickness direction of the battery cell, there is a portion of back packaging material between the bus bar and the first insulating layer. The portion of the back packaging material between the bus bar and the first insulating layer can play the role of buffering contact between the bus bar and the battery cell, reducing the risk of hidden cracks in the battery cell.

[0042] In some possible implementations, in the length direction of the busbar, at least one end of the busbar is connected to the outermost first welding strip, and the end of the busbar exceeds the outermost first welding strip by more than 1 mm or covers at least 80% of the width of the outermost first welding strip. In this way, it can be fully welded with the outermost first welding strip, or a sufficient welding process window is reserved, and the excess length is convenient for connection with other leads of the photovoltaic module.

[0043] In a second aspect, the present invention further provides a method for preparing a photovoltaic module, comprising:

[0044] Printing insulating glue at the position corresponding to the bus bar on the back side of the battery cell to form a first insulating layer arranged at intervals along the extension direction of the fine gate electrode of the battery cell, the first insulating layer covering a portion of the fine gate electrode of the second polarity;

[0045] Printing conductive glue on the back pad of the battery cell;

[0046] Layout and welding: Lay the front cover plate and the front packaging film in sequence, and lay all the cells of the photovoltaic module on the front packaging film, with the front of the cell facing downward; lay and fix the welding strips, insulating blocks and bus bars on the back of the cell; wherein the first welding strip is electrically connected to the fine grid electrode of the first polarity, and the second welding strip is electrically connected to the fine grid electrode of the second polarity; the insulating blocks and the first insulating layer are alternately arranged along the extension direction of the fine grid electrode, and the insulating blocks cover part of the fine grid electrode of the second polarity and part of the second welding strip; the bus bar corresponds to the area of ​​the first insulating layer and the insulating block, and the bus bar extends along the length direction of the fine grid electrode; the bus bar is electrically connected to the first welding strip, and the bus bar and the second welding strip are electrically isolated by the insulating block; the bus bar and the fine grid electrode of the second polarity are electrically isolated by the alternately arranged insulating blocks and the first insulating layer;

[0047] The back side packaging film and back sheet are laid on the back side of the battery cell and laminated.

[0048] When the above technical solution is adopted, a photovoltaic module with the same structure as the first aspect can be obtained. The beneficial effects can be found in the above description of the photovoltaic module and will not be repeated here. In addition, after all the battery cells are laid on the front packaging cover plate, the welding strips, bus bars and insulating blocks are uniformly laid on the back of the battery cells and fixed together. Compared with the original method of first making the battery string, then arranging the battery string and welding the bus bars, it can simplify the layout and welding process, reduce the process difficulty, improve the production efficiency of photovoltaic modules, and improve the module yield.

[0049] In some possible implementations, laying and fixing the welding ribbon, insulating block and bus bar on the back of the battery cell includes:

[0050] First, lay the welding strip on the back of the battery cell; then lay the insulating block on the back of the battery cell, and the insulating block covers part of the second welding strip; finally, lay the bus bar on the back of the battery cell. This method can facilitate the welding of the welding strip to the battery cell, and the welding of the bus bar to the first welding strip, and improve the welding strength. Since the stacking structure of the welding strip, the insulating block, and the bus bar is simple, the welding point between the welding strip and the bus bar does not need to be bent, so that the first welding strip can contact the battery cell smoothly, which can reduce the risk of hidden cracks on the battery cell caused by the pressure on the first welding strip.

[0051] Alternatively, a bus bar is first laid on the back of the cell, and then an insulating block is laid on the back of the cell; finally, a welding strip is laid on the back of the cell, and the bus bar and the second welding strip are electrically isolated by the insulating block. At this time, the welding strip is located at the top, and the welding effect of the bus bar can be easily and quickly determined by naked eyes.

[0052] In some possible implementations, laying and fixing the soldering tape on the back of the cell includes: first pre-fixing the soldering tape using a fixed glue point on the cell, and then fixing the soldering tape using infrared, laser or lamination. Pre-fixing the soldering tape using a fixed glue point ensures that the soldering tape is not easily displaced during the cell transfer and welding process, thereby improving the soldering accuracy of the soldering tape. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0054] Figure 1 A schematic structural diagram of an insulating region in a photovoltaic module provided by an embodiment of the present invention;

[0055] Figure 2 A schematic diagram of the arrangement structure of a bus bar in a photovoltaic module provided by an embodiment of the present invention;

[0056] Figure 3 for Figure 2 Schematic cross-sectional view of section AA;

[0057] Figure 4 A schematic diagram of the arrangement structure of bus bars in another photovoltaic module provided by an embodiment of the present invention;

[0058] Figure 5 for Figure 4 Schematic diagram of the cross-section of the middle BB section;

[0059] Figure 6 A schematic diagram of the arrangement structure of a bus bar in another photovoltaic module provided by an embodiment of the present invention;

[0060] Figure 7 for Figure 6 Schematic cross-sectional view of the CC section;

[0061] Figure 8 A schematic diagram of the arrangement structure of a bus bar in another photovoltaic module provided by an embodiment of the present invention;

[0062] Fig. 9 A schematic diagram of the structure of another insulating region provided by an embodiment of the present invention;

[0063] Fig.10 A schematic diagram of the structure of another insulating region provided by an embodiment of the present invention;

[0064] Fig.11 A schematic structural diagram of another insulating region provided in an embodiment of the present invention.

[0065] Figure numerals: 1 is a battery cell, 2 is an insulating area, 21 is a first insulating layer, 22 is a second insulating layer, 23 is a first insulating rubber strip, 24 is an insulating rubber layer, 25 is a second insulating rubber strip, 3 is a welding strip insulating member, 4 is a welding strip, 41 is a first welding strip, 42 is a second welding strip, 5 is a bus bar, and 6 is an insulating block. DETAILED DESCRIPTION

[0066] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0067] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0068] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The meaning of "several" is one or more, unless otherwise clearly and specifically defined.

[0069] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0070] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0071] like Figure 1-Figure 11As shown, an embodiment of the present invention provides a photovoltaic module, including a cell 1, a welding strip 4, a bus bar 5 and an insulating block 6, and the back of the cell 1 has a fine grid electrode and a first insulating layer 21. For a back-contact cell, the positive and negative electrodes of the electrode are both located on the back of the cell 1, and accordingly, the fine grid electrode includes a positive fine grid electrode and a negative fine grid electrode, and the positive fine grid electrode and the negative fine grid electrode are each connected to a different welding strip 4 through an electrical connection portion (such as a welding pad, a thickened section of the fine grid, or an electrical connection point connected to the fine grid, etc.), and the different welding strips 4 are connected to the corresponding bus bar 5. The first insulating layer 21 is obtained by printing insulating glue on the area on the back of the cell where the bus bar 5 is to be set, and the first insulating layer 21 covers part of the fine grid electrode of the second polarity. The first welding strip 41 is electrically connected to the fine grid electrode of the first polarity, and at the same time, the first welding strip 41 is insulated from the fine grid electrode of the second polarity; the second welding strip 42 is electrically connected to the fine grid electrode of the second polarity, and at the same time, the second welding strip 42 is insulated from the fine grid electrode of the first polarity; the insulating block 6 is located on the back side of the battery cell 1, and the insulating block 6 and the first insulating layer 21 are alternately arranged along the extension direction of the fine grid electrode; on the projection of the battery cell 1, the insulating block 6 covers part of the fine grid electrode of the second polarity, and on the projection of the battery cell 1 or the back plate of the photovoltaic module, the insulating block 6 covers part of the second welding strip 42; the bus bar 5 is located on the back side of the battery cell 1 in the area corresponding to the first insulating layer 21 and the insulating block 6, and the bus bar 5 extends along the length direction of the fine grid electrode; the bus bar 5 is electrically connected to the first welding strip 41, and the bus bar 5 and the second welding strip 42 are electrically isolated by the insulating block 6; the bus bar 5 and the fine grid electrode of the second polarity are electrically isolated by the alternately arranged insulating blocks 6 and the first insulating layer 21.

[0072] For example, taking a battery string that uses a plurality of half-cell batteries connected in series as an example, the bus bar 5 extends in a direction parallel to the long side of the half-cell battery. Figure 2-Figure 8 As shown, a bus bar 5 is conductively connected to the first welding strip 41, and is electrically isolated from the second welding strip 42 by an insulating block 6. The first welding strip 41 is conductively connected to one of the positive fine grid electrode and the negative fine grid electrode, and the second welding strip 42 is conductively connected to the other of the positive fine grid electrode and the negative fine grid electrode. The welding strip 4 in the present application is not limited to a metal wire for welding, as long as the battery cell 1 and the welding strip 4 are fixed and conductively connected.

[0073] In the case of adopting the above technical solution, in order to reduce the ineffective area occupied by the busbar in the photovoltaic module, the busbar 5 is arranged on the back of the battery cell 1. In this case, the first insulating layer 21 and the insulating block 6 are alternately arranged along the extension direction of the fine grid electrode at the position corresponding to the busbar 5 on the back of the battery cell 1. The insulating block 6 covers part of the fine grid electrode of the second polarity and part of the second welding strip 42, and the first insulating layer 21 covers part of the fine grid electrode of the second polarity; the busbar 5 is electrically connected to the first welding strip 41, and the busbar 5 and the second welding strip 42 are electrically isolated by the insulating block 6; the busbar 5 and the fine grid electrode of the second polarity are electrically isolated by the alternately arranged insulating blocks 6 and the first insulating layer 21. First of all, the present application can set the busbar 5 at any position on the back of the battery cell 1, extending along the length direction of the fine grid electrode. The position selection of the busbar 5 is relatively flexible and diverse. It only needs to print the first insulating layer 21 and lay the insulating block 6 at the position corresponding to the busbar 5 to achieve electrical isolation from the fine grid electrode of the second polarity and the welding strip 4. The insulating block 6 is arranged on the second welding strip 42, at the position where the bus bar 5 is connected to the first welding strip 41, and the bus bar 5 and the fine grid of the second polarity near the first welding strip 41 are insulated by the first insulating layer 21, so that there is no obstruction or pad between the bus bar 5 and the first welding strip 41, and effective welding can be achieved more easily, reducing the problems of cold welding and difficulty in welding when the insulating block 6 is present near the first welding strip 41.

[0074] In addition, based on the arrangement structure of the bus bar 5, welding ribbon 4, insulating block 6, etc. of the photovoltaic module on the back of the battery cell 1, a simpler layout and welding process can be selected, that is, after all the battery cells 1 are laid on the front packaging cover, the welding ribbon 4, bus bar 5 and insulating block 6 can be uniformly laid on the back of the battery cell 1 and fixed together. Compared with the original method of first making the battery string, then arranging the battery string and welding the bus bar, it can simplify the process, reduce the process difficulty, improve the production efficiency of photovoltaic modules, and improve the module yield.

[0075] like Figure 1 and 8As shown, in some embodiments, the projections of the insulating block 6 and the first insulating layer 21 on the battery cell 1 are alternately connected, or the projections of the insulating block 6 and the first insulating layer 21 on the battery cell 1 have an overlapping area at the connection. For example, the insulating block 6 can directly contact the back of the battery cell 1 and directly connect or overlap with the first insulating layer 21; or, the insulating block 6 does not contact the back of the battery cell 1 (related to the stacking sequence of the insulating block 6, the welding ribbon 4 and the bus bar 5, and the specific stacking structure will be described below), and there is a gap between the battery cell 1 and the battery cell 1 in the thickness direction of the battery cell 1, so the projections of the insulating block 6 and the first insulating layer 21 on the battery cell 1 have an overlapping area at the connection. In this way, when the busbar 5 is arranged in the region corresponding to the insulating block 6 and the first insulating layer 21, the insulating block 6 is connected or overlapped with the first insulating layer 21, so as to avoid the appearance of a gap between the insulating block 6 and the first insulating layer 21 in the length direction of the fine gate electrode, and avoid the fine gate electrode of the second polarity from being exposed in the gap, so as to better avoid the conductive contact between the busbar 5 and the fine gate electrode of the second polarity below, prevent short circuit, and improve insulation performance. Of course, in the thickness direction of the battery cell 1, if the insulation distance between the busbar 5 and the fine gate electrode of the second polarity is large enough, the insulating block 6 and the first insulating layer 21 may not be connected or overlapped.

[0076] In some embodiments, along the length direction of the fine gate electrode, the length of the overlapping area between the insulating block 6 and the projection of the first insulating layer 21 on the battery cell 1 is greater than 0.5 mm. Specifically, the length of the overlapping area can be greater than 0.5 mm, 0.7 mm, 1 mm, 1.2 mm, 1.5 mm, 2 mm, 3 mm, etc. Since the edge of the insulating block 6 is uneven and the thickness is relatively thin at some positions, the edge position of the first insulating layer 21 may be shorter or less thick. The insulating block 6 overlaps with the first insulating layer 21, and the length of the overlapping area is greater than 0.5 mm, which can avoid the insulation performance of the first insulating layer 21 and the edge position of the insulating block 6 from being reduced.

[0077] like Figure 1 and Figure 8As shown, in some possible implementations, the back of the battery cell 1 also has a second insulating layer 22, and the first insulating layer 21 and the second insulating layer 22 are arranged alternately along the length direction of the bus bar 5. The second insulating layer 22 can also be obtained by printing insulating glue on the back of the battery cell 1. The second insulating layer 22 can cover the fine grid electrode of the first polarity; the insulating block 6 is stacked above the second insulating layer 22. By setting the second insulating layer 22 to cover the fine grid electrode of the first polarity, it is possible to avoid the second welding strip 42 here from contacting the fine grid electrode of the first polarity below when the position is offset, thereby improving the insulation performance. In addition, the second insulating layer 22 only needs to be printed longer on the basis of the welding strip insulating member 3 originally printed below the second welding strip 42 on the back of the battery cell 1, without adding additional process steps. The superimposed insulating block 6 can realize the placement of the bus bar 5, and the bus bar 5 is electrically isolated from the second welding strip 42 by the insulating block 6. It should be understood that the first and second insulating layers are made synchronously and with the same material as the welding strip insulating member on the battery cell. The first insulating layer 21, the second insulating layer 22 and the insulating block 6 constitute the insulating region 2. The first insulating layer 21 and the second insulating layer 22 are arranged alternately, which improves the versatility of the battery cell 1 and facilitates the use of bus bars 5 of different polarities. That is, the first insulating layer and the second insulating layer can be interchanged without selecting the battery cell, thereby improving the preparation efficiency.

[0078] like Figure 1 As shown, in some possible implementations, along the length direction of the bus bar 5, the difference between the length of the first insulating layer 21 and the length of the second insulating layer 22 is less than or equal to 2 mm, specifically, the length difference may be 0 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, etc. Along the width direction of the bus bar 5, the difference between the width of the first insulating layer 21 and the width of the second insulating layer 22 is less than or equal to 2 mm, specifically, the width difference may be 0 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2 mm, etc. The length of the first insulating layer 21 may be longer, shorter, or equal to the length of the second insulating layer 22, and the width of the first insulating layer 21 may be wider, shorter, or equal to the width of the second insulating layer 22. In this way, the length and / or width of the first insulating layer 21 and the second insulating layer 22 are similar. When the welding strip connected to the bus bar 5 is replaced, the insulating block 6 is replaced from above the second insulating layer 22 to above the first insulating layer 21, and the second insulating layer 22 can still provide sufficient insulation performance for the bus bar 5 and the fine grid below. The battery cell has strong versatility, and there is no need to perform multiple designs, multiple processes and screening of battery cells during production.

[0079] like Figure 1As shown, in some embodiments, along the width direction of the busbar 5, the first insulating layer 21 and the second insulating layer 22 are crossed; that is, the first insulating layer 21 and the second insulating layer 22 are alternately connected in the length direction of the busbar 5 as a whole (for example, an end fork finger design), and the printing patterns of the first insulating layer 21 and the second insulating layer 22 are simplified through repetitive arrangement, thereby improving the versatility of the first insulating layer 21 and the second insulating layer 22, and facilitating the use of busbars 5 of different polarities without the need to select the battery cell 1, thereby improving the preparation efficiency.

[0080] In some embodiments, the first insulating layer 21 and the second insulating layer 22 are made of the same material and have the same thickness, and are printed on the battery cell 1 simultaneously. In this way, the first insulating layer 21 and the second insulating layer 22 can be printed on the battery cell 1 simultaneously in the same printing process, which simplifies the preparation process and improves the preparation efficiency. It should be understood that the same thickness can allow a certain process error. Of course, the materials and thicknesses of the first insulating layer 21 and the second insulating layer 22 can also be different, and different materials and thicknesses can be selected as needed.

[0081] In some embodiments, the first insulating layer 21 and the second insulating layer 22 are transparent adhesive layers. The first insulating layer 21 and the second insulating layer 22 are transparent adhesive layers, which can improve the light utilization rate of the battery cell 1.

[0082] like Figure 8 As shown, in some possible implementations, along the width direction of the busbar 5, the width of the insulating block 6 is 1mm to 5mm wider than the width of the busbar 5, and can be specifically 1mm, 2mm, 3mm, 4mm, 5mm, etc.; along the length direction of the busbar 5, the length of the insulating block 6 is 0.5mm to 4mm longer than the length of the second insulating layer 22 stacked with the insulating block 6, and can be specifically 0.5mm, 1mm, 2mm, 3mm, 4mm, etc.

[0083] When the above technical solution is adopted, the width of the insulating block 6 can ensure the insulation effect between the bus bar 5 and the second welding strip 42. The length of the insulating block 6 is longer than the length of the second insulating layer 22 stacked therewith, so that there is an overlapping area between the edge of the insulating block 6 and the adjacent first insulating layer 21, so as to avoid the appearance of a gap between the insulating block 6 and the first insulating layer 21 in the length direction of the fine gate electrode, and avoid the fine gate electrode of the second polarity from being exposed in the gap, which can better avoid the conductive contact between the bus bar 5 and the fine gate electrode of the second polarity below, prevent short circuit, and improve insulation performance. In addition, the length and width of the insulating block 6 are not too large, which reduces shading and saves materials.

[0084] like Figure 2 , Figure 4 and Figure 6As shown, in some embodiments, in the length direction of the busbar 5, the end of the insulating region 2 composed of the first insulating layer 21 and the insulating block 6 exceeds the end of the busbar 5 by a distance of 1mm to 5mm, specifically 1mm, 2mm, 3mm, 4mm, 5mm, etc. In the width direction of the busbar 5, the side edge of the insulating region 2 composed of the first insulating layer 21 and the insulating block 6 exceeds the side edge of the busbar 5 by a distance of 1mm to 5mm, specifically 1mm, 2mm, 3mm, 4mm, 5mm, etc. In addition, in the thickness direction of the battery cell 1, the insulation distance between the busbar 5 and the second welding strip 42 and the fine grid electrode of the second polarity is greater than or equal to 10μm.

[0085] When the above technical solution is adopted, the size relationship between the insulating area 2 and the busbar 5 can not only meet the insulation requirements, but also save the material of the insulating area 2, and prevent the first insulating layer 21 from being too large relative to the busbar and warping. The busbar 5 is located in the insulating area 2, which can achieve a more reliable insulation effect between the busbar 5 and the fine grid electrode of the second polarity and the second welding strip 42. The insulation distance between the busbar 5 and the second welding strip 42 and the fine grid electrode of the second polarity is greater than or equal to 10μm, which ensures reliable insulation between the busbar 5 and the second welding strip 42 and the fine grid electrode of the second polarity. Even if there is a situation where there is no complete shielding between the busbar 5 and the fine grid electrode of the second polarity, and between the busbar and the second welding strip 42, reliable insulation can be met through sufficient insulation distance. The insulation distance between the busbar 5 and the fine grid electrode of the second polarity can be reflected by the thickness of the second insulating layer, or by the sum of the thickness of the second insulating layer and the insulating block, and the insulation distance between the busbar 5 and the second welding strip 42 can be reflected by the thickness of the insulating block.

[0086] For example, the thickness of the first insulating layer 21 and the second insulating layer 22 may be 10 μm to 1000 μm.

[0087] In some embodiments, the insulating block 6 is a tape, and the tape is pasted on the battery cell 1. By pasting it on the battery cell 1, compared with directly placing it on the battery cell 1, the insulating block 6 can be pre-fixed with the battery cell 1 to prevent the insulating block 6 from shifting during the movement and lamination of the components, thereby ensuring the insulation reliability. The tape is made of a flexible material, which can reduce the risk of fracturing the battery cell 1. The insulating block can be a multi-layer composite film, etc., and the color can be white, black or other colors. The thickness of the insulating block is 50μm to 300um.

[0088] In some embodiments, the insulating block 6 is a rectangular insulating block 6. In this way, the insulating block 6 can be prevented from intruding between the bus bar 5 and the first welding strip 41, reducing the risk of poor welding between the bus bar 5 and the first welding strip 41, while reducing the height difference caused by the insulating block 6 and reducing the risk of hidden cracks.

[0089] like Figure 6 and Figure 8 As shown, in some embodiments, the bus bar 5 is located at a non-edge position of the battery cell 1. In the direction in which the battery cells 1 are connected in series, the battery cell 1 has two edge positions and a non-edge position located between the edge positions. Correspondingly, the first insulating layer 21, the second insulating layer 22 and the insulating block 6 are arranged at the non-edge position of the battery cell 1. The edge bus bar and the middle bus bar of the photovoltaic module can both be located at the non-edge position of the battery cell 1 where they are respectively set. Among them, the edge bus bar refers to the bus bar arranged on the battery cell of the photovoltaic module near the edge of the module, and the middle bus bar refers to the bus bar arranged on the battery cell of the photovoltaic module near the middle position of the module. The space in the middle of the battery cell 1 is large, and the requirements for the placement accuracy of the bus bar 5 are low, which can reduce the process difficulty.

[0090] like Figure 2 and Figure 4 As shown, in other embodiments, the busbar 5 is located at the edge of the cell 1, and correspondingly, the first insulating layer 21, the second insulating layer 22 and the insulating block 6 are arranged at at least one edge of the cell 1. The edge busbars and the middle busbars of the photovoltaic module can be located at the edges of the respective cells 1. The busbar 5 can exert a certain pressure on the cell 1 with warped edges, thereby reducing the degree of warping and reducing the risk of hidden cracks and splits of the cell 1.

[0091] In some other embodiments, a busbar 5 covers part of the previous battery cell 1 and part of the next battery cell 1; the covering width of the busbar 5 on the previous battery cell 1 is 1mm~5mm, specifically 1mm, 2mm, 3mm, 4mm, 5mm, etc.; the covering width of the busbar 5 on the next battery cell 1 is 1mm~5mm, specifically 1mm, 2mm, 3mm, 4mm, 5mm, etc.; the width of the busbar 5 covering the previous battery cell 1 and the width covering the next battery cell 1 may be the same or different; the spacing between the previous battery cell 1 and the next battery cell 1 is 0~2mm, that is, the spacing between the battery cells 1 covered by the busbar is 0~2mm, specifically 0mm, 1mm, 2mm, etc. That is, a bus bar 5 crosses and connects the previous cell 1 and the next cell 1, and correspondingly, the first insulating layer 21 and the second insulating layer 22 are provided on the two adjacent edges of the previous cell 1 and the next cell 1, and the insulating block 6 crosses and covers the edges of the previous cell 1 and the next cell 1. The edge bus bar and the middle bus bar of the photovoltaic module can be arranged to cross the previous cell 1 and the next cell 1.

[0092] In the case of the above-mentioned busbar arrangement forms, the busbar 5 can be located at the edge position or non-edge position of the back of the battery cell 1 or cover the parts of two adjacent battery cells 1 at the same time, which expands the selection range of the location of the busbar 5 on the back of the battery cell 1, facilitates the setting of the busbar 5, and can be selected according to the layout position of the battery cell in the photovoltaic module and the current transmission needs to be set at a suitable position on the back of the battery cell 1, and the structure in the present application can ensure the reliable insulation of the busbar 5 and the fine grid electrode of the second polarity on the battery cell 1 and the second welding strip 42. When the busbar 5 covers the parts of two adjacent battery cells 1 at the same time, the busbar 5 can be designed to be thin and wide to ensure the current transmission efficiency while avoiding the hidden cracks of the battery cell 1 caused by excessive thickness. At this time, the busbar 5 can avoid the risk of hidden cracks or short circuits caused by excessive stress caused by being set on a certain battery cell 1, and then can play a role in dispersing the stacking stress of the busbar 5 and improve the yield of the component.

[0093] In some embodiments, in the width direction of the busbar 5, a busbar 5 of the photovoltaic module only covers one cell 1. A busbar 5 of the photovoltaic module only covers one cell 1, which can facilitate the positioning and fixing of the busbar 5, and there is no need to consider the positions of two cells 1 at the same time. Covering only one cell 1 can avoid the unbalanced load bearing due to the height difference between the two cells 1 in the thickness direction, which is easy to cause hidden cracks in the cell 1.

[0094] In some embodiments, the patterns of the first insulating layer 21 on all cells 1 in the photovoltaic module are the same. If the cell 1 has a second insulating layer 22, the patterns of the second insulating layer 22 on all cells 1 are also the same. For example, the patterns of the first and second insulating layers of each cell 1 are as follows: Figure 1 With such arrangement, during the production process, there is no need to distinguish between the battery cells 1 for connecting the busbar 5 and the battery cells 1 not connected to the busbar, so that the versatility of all battery cells 1 is improved, and there is no need to select battery cells 1 with a specific pattern insulation layer separately, thereby improving the production efficiency.

[0095] like Fig. 9As shown, this embodiment provides a specific form of the first insulating layer 21 and / or the second insulating layer 22, that is, the first insulating layer 21 and / or the second insulating layer 22 is composed of a plurality of first insulating rubber strips 23 that are parallel to each other and arranged at intervals. The first insulating rubber strips 23 extend continuously along the length direction of the bus bar 5. Take the first insulating layer 21 using the first insulating rubber strips 23 as an example for explanation. The first insulating rubber strips 23 cover the fine gate electrodes of the second polarity of the battery cell 1. There are multiple fine gate electrodes parallel to the length direction of the bus bar 5, and the multiple fine gate electrodes are arranged at intervals along the width direction of the bus bar 5. The fine gate electrodes include alternating positive fine gate electrodes and negative fine gate electrodes. The fine gate electrodes with the same electrical property (such as one of the positive fine gate electrode and the negative fine gate electrode) are connected by the welding strip 4. The welding strip 4 is electrically isolated from the fine gate electrodes with conductive anisotropy (such as the other of the positive fine gate electrode and the negative fine gate electrode) by the welding strip insulating member 3. The welding strip insulating member 3 can be printed on the battery cell 1 together with the first insulating layer 21. The welding strip insulating member 3 is used to cover the fine gate electrodes with conductive anisotropy near the welding strip 4, so that the welding strip 4 is electrically isolated from the fine gate electrodes with conductive anisotropy below. The total area width between the two outermost first insulating strips 23 in the first insulating layer 21 is greater than the width of the bus bar 5. The multiple first insulating strips 23 can support the bus bar 5, so that a gap is formed between the bus bar 5 and the fine gate electrode of the second polarity of the battery cell 1, and the first insulating strips 23 cover the fine gate electrode of the second polarity, which can achieve electrical isolation between the bus bar 5 and the fine gate electrode of the second polarity. At the same time, the multiple first insulating strips 23 do not completely cover the edge of the battery cell 1, so it is possible to save the material of the insulating layer and reduce the warping of the battery cell caused by the provision of the insulating strips. The first insulating strip 23 can specifically be an insulating glue (such as green, black, transparent, etc.) printed on the back of the battery cell 1. The first insulating strip 23 is prepared by a printing process, which can simplify the process, improve the preparation efficiency, and has a good fit with the back of the battery cell and high insulation stability.

[0096] It should be noted that when the second insulating layer 22 adopts the first insulating rubber strip 23, the first insulating rubber strip 23 can cover the fine gate electrode of the first polarity. When the first insulating layer 21 and the second insulating layer 22 both adopt the first insulating rubber strip 23, since the first insulating layer 21 and the second insulating layer 22 are alternately arranged along the length direction of the bus bar 5, the following can be obtained: Figure 1 In the insulating region structure shown, the lengths of the first insulating rubber strip 23 of the first insulating layer 21 and the first insulating rubber strip 23 of the second insulating layer 22 can be the same, which is equal to the spacing between the first welding strip 41 and the second welding strip 42. The first insulating rubber strip 23 of the first insulating layer 21 and the first insulating rubber strip 23 of the second insulating layer 22 are alternated in the width direction of the busbar 5.

[0097] Or, if Fig. 9As shown, the insulating region 2 composed of the first insulating layer 21 is composed of multiple continuous first insulating rubber strips 23, that is, the first insulating layer 21 is a continuous and uninterrupted structure, covering the fine gate electrode of the second polarity, and the insulating block 6 covers the position corresponding to the second welding strip 42.

[0098] Further, the length of the first insulating rubber strip 23 is 0.5 mm to 1 mm smaller than the edge length of the battery cell 1, and can be 0.5 mm, 0.7 mm, 0.8 mm, 1 mm, etc. The width of the first insulating rubber strip 23 can be 0.2 mm to 1 mm, and can be 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, etc. The thickness of the first insulating rubber strip 23 can be 10 μm to 100 μm, and can be 10 μm, 30 μm, 50 μm, 70 μm, 90 μm, 100 μm, etc. The size of the first insulating rubber strip 23 can meet the insulation requirements and save the material of the insulating rubber strip.

[0099] like Fig.10 As shown, this embodiment provides a second form of the first insulating layer 21 and / or the second insulating layer 22, that is, the first insulating layer 21 and the second insulating layer 22 are insulating adhesive layers 24 that are integrally covered on the area of ​​the bus bar 5 corresponding to the battery cell 1. The width of the insulating adhesive layer 24 is greater than the width of the bus bar 5, and the thickness of the insulating adhesive layer 24 can be 10μm to 100μm, specifically 10μm, 30μm, 50μm, 70μm, 90μm, 100μm, etc. The insulating adhesive layer 24 can be an insulating adhesive printed on the battery cell. The insulating adhesive layer 24 can support the entire surface of the bus bar 5, and realizes the electrical isolation of the bus bar 5 from the fine grid electrode of the second polarity on the battery cell 1. At this time, not only the insulation effect of the bus bar 5 is relatively good, but also it can play a better role in protecting the fine grid electrode on the battery cell 1, reducing the adverse effect of the welding heat of the fine grid silver bus bar on the fine grid. The first insulating layer 21 and the second insulating layer 22 may be segmented insulating rubber layers 24 or may be a continuous insulating rubber layer 24. Fig.10 The bus bar 5 is insulated from the second welding strip 42 by the insulating block 6 ( Fig.10 not shown).

[0100] like Fig.11As shown, this embodiment provides a third form of the first insulating layer 21 and the second insulating layer 22, that is, the first insulating layer 21 and / or the second insulating layer 22 are a plurality of rows and columns of second insulating rubber strips 25 arranged in parallel and at intervals. Regardless of the first insulating layer 21 or the second insulating layer 22, part of the second insulating rubber strips 25 cover the fine gate electrode of the second polarity, and / or, part of the second insulating rubber strips 25 cover the fine gate electrode of the first polarity, and / or, part of the second insulating rubber strips 25 are located between the fine gate electrode of the first polarity and the fine gate electrode of the second polarity. The third insulating layer does not require the second insulating rubber strips 25 to cover the fine gate electrode of the second polarity. The insulating layer can partially support the bus bar 5 and can electrically isolate the bus bar 5 from the fine gate electrode of the second polarity on the battery cell 1 through a spatial interval. The insulating layer can save the material of the insulating layer, and can disperse the second insulating rubber strips 25 to a large extent, shorten the length of the second insulating rubber strips 25, further reduce the warping of the battery cell caused by the second insulating rubber strips 25, and reduce the hidden cracks of the battery cell. The second insulating adhesive strip 25 may be an insulating adhesive printed on the battery cell. Fig.11 When the battery cell 1 is connected, the bus bar 5 is electrically connected to the first welding ribbon 41 , insulated from the second welding ribbon 42 by the insulating block 6 , and isolated from the electrode on the battery cell 1 by the second insulating tape 25 .

[0101] Furthermore, the width of the second insulating rubber strip 25 is 0.2 mm to 1 mm, the length of the second insulating rubber strip 25 can be 0.5 mm to 10 mm, and the thickness of the second insulating rubber strip 25 is 10 μm to 100 μm. This size can meet the electrical isolation requirements of the bus bar 5 and the fine grid electrode of the second polarity on the battery cell 1, and can save the material of the insulating layer.

[0102] The above three forms of insulating layers can be used as the first insulating layer 21 and / or the second insulating layer 22 of the edge bus bar of the corresponding photovoltaic module, and can also be used as the first insulating layer 21 and / or the second insulating layer 22 of the corresponding middle bus bar. All of them are applicable and can be correspondingly provided with insulating blocks 6. Fig. 9 , Fig.10 , Fig.11 When the battery cell 1 shown is connected to the bus bar 5, the bus bar 5 and the second welding strip 42 are isolated by the insulating block 6, which has good insulation protection. At this time, the length of the welding strip at the end of the battery cell 1 has a large safety length.

[0103] In some embodiments, along the width direction of the busbar 5, the connection length between the busbar 5 and a first welding strip 41 is greater than or equal to 20% of the width of the busbar 5, and can be specifically 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, etc. In this way, the welding interconnection area between the first welding strip 41 and the busbar 5 is sufficient to meet the conductive transmission performance and welding reliability, and can reduce current loss. There are multiple connection points between the busbar 5 and the first welding strip 41, and at least 2 connection points partially overlap. The connection point can be rectangular, elliptical, or circular. Specifically, a laser welding process can be used to connect the busbar 5 to the first welding strip 41 and form a connection point.

[0104] like Figure 2 , Figure 4 , Figure 6 and Figure 8 As shown, in some embodiments, along the width direction of the bus bar 5, the welding strips 4 fixed on the bus bar 5 are aligned or connected on the bus bar 5. For example, Figure 2 As shown, taking the connection between the first welding ribbon 41 and the bus bar 5 as an example, the previous battery cell 1 ( Figure 2 The first welding strip 41 on the left battery cell 1) and the next battery cell 1 ( Figure 2 The first welding strip 41 on the right battery cell 1) is aligned or connected on the bus bar 5. The welding strip 4 on the previous battery cell 1 and the welding strip 4 on the next battery cell 1 are aligned on the bus bar 5 to reduce the difference in creepage distance between the upper and lower parts of the module, shorten the side length of the photovoltaic module, and reduce the blank area of ​​the photovoltaic module. The first welding strip 41 on the previous battery cell 1 and the first welding strip 41 on the next battery cell 1 are connected on the bus bar 5 to reduce current loss. It should be understood that on the bus bar 5, the first welding strip 41 of the previous battery cell 1 and the first welding strip 41 of the next battery cell 1 can also be designed to be staggered.

[0105] In some embodiments, the photovoltaic module further includes a buffer film between the bus bar 5 and the back packaging film of the photovoltaic module. The buffer film covers the bus bar 5, so that when the bus bar 5 is under pressure, the buffer film buffers the position of the bus bar 5, thereby reducing the risk of hidden cracks in the battery cell 1.

[0106] Exemplarily, the thickness of the buffer film is 200 μm to 1000 μm, specifically 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, etc. And / or, the width of the buffer film is 0 to 100 mm wider than the width of the bus bar 5, specifically 0 mm, 10 mm, 20 mm, 40 mm, 50 mm, 70 mm, 90 mm, 100 mm, etc.; and / or, the length of the buffer film is 0 to 5 mm longer than the length of the bus bar 5, specifically 0 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, etc.; and / or, the material of the buffer film is a material with elasticity and durability such as POE (polyolefin elastomer), EPE (expandable polyethylene) or EVA (ethylene-vinyl acetate copolymer). At this time, the selection of materials can ensure that the busbar 5 has a good buffering effect; the design of the thickness of the buffer film can take into account both the buffering effect and the stacking thickness, avoiding the problem of lamination bubbles caused by excessive thickness; the design of the width and length of the buffer film can ensure that the buffer film covers the entire busbar 5, reducing the problem of local uneven force.

[0107] like Figure 2 , Figure 3 , Figure 6 and Figure 7 As shown, in some embodiments, the bus bar 5 is located on the side of the first welding strip 41 and the second welding strip 42 away from the battery cell 1, and the height difference between the position of the bus bar 5 corresponding to the first welding strip 41 and the position corresponding to the second welding strip 42 is less than or equal to 100 mm; and the cross section of the welding strip 4 is rectangular. Figure 3 As shown, the bus bar 5 is located above the welding strip 4. At the position corresponding to the second welding strip 42, the battery cell 1, the second insulating layer 22, the second welding strip 42, the insulating block 6 and the bus bar 5 are stacked in sequence. At the position corresponding to the first welding strip 41, the battery cell 1, the first insulating layer 21, the first welding strip 41 and the bus bar 5 are stacked in sequence. This structure can facilitate the welding of the bus bar 5 and the welding strip 4, improve the welding strength and welding efficiency. Since the stacking structure of the welding strip 4 and the bus bar 5 is simple, the welding point of the welding strip 4 and the bus bar 5 does not need to be bent, so that the welding strip 4 can be in flat contact with the battery cell 1, which can reduce the risk of hidden cracks on the battery cell 1 caused by the pressure on the welding strip 4. The height difference between the positions of the bus bar 5 corresponding to the two welding strips 4 is less than or equal to 100 mm, which can avoid the battery cell 1 from being hidden cracked due to the uneven force on the battery cell 1 due to the large height difference. The welding ribbon 4 is a flat welding ribbon, which can increase the contact area with the battery cell 1 and reduce the pressure. When the welding ribbon 4 is under pressure, the risk of hidden cracks on the battery cell 1 can be reduced.

[0108] Of course, if Figure 4 and Figure 5As shown, the welding strip 4 can also be located above the bus bar 5, and the battery cell 1, the second insulating layer 22, the bus bar 5, the insulating block 6 and the second welding strip 42 are stacked in sequence at the position corresponding to the second welding strip 42. The battery cell 1, the first insulating layer 21, the bus bar 5 and the first welding strip 41 are stacked in sequence at the position corresponding to the first welding strip 41. At this time, the welding strip 4 is located at the top, and the welding effect of the bus bar 5 can be conveniently and quickly determined by naked eyes.

[0109] In some possible implementations, the distance between the cover plate and the back plate of the photovoltaic module is A, and the sum of the thickness of the battery cell 1, the fine grid electrode and the welding strip 4 is B, and B accounts for less than 79% of A. Since between the cover plate and the back plate, in addition to the battery cell 1, the fine grid electrode, the welding strip 4 and the bus bar 5, some adhesive film layers need to be stacked to fix and buffer the battery cell 1, the welding strip 4 and the bus bar 5, therefore, in order to improve the fixing and buffering effect of the adhesive film layer and reduce the hidden cracks or dislocations caused to the battery cell 1 during the component lamination process, it is necessary to provide sufficient thickness space for the adhesive film layer. Therefore, the sum of the thickness of the battery cell 1, the fine grid electrode and the welding strip 4 accounts for less than 79% of the distance between the cover plate and the back plate, and the remaining distance is left for the adhesive film layer. That is, the thickness of the adhesive film layer between the cover plate and the back plate can account for more than 31%.

[0110] In some embodiments, the photovoltaic module includes a battery group composed of all the cells 1, the battery group includes m columns of cells, m is an integer greater than or equal to 2, and one column of cells includes more than 2 battery strings; the difference in the minimum distance between the battery group and each edge of the cover of the photovoltaic module is less than 0.5mm, and can be specifically 0mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm and 0.5mm, etc. In this way, the difference in the distance between the battery group and the corresponding edge of the cover is small, which can reduce the side length of the photovoltaic module and improve the unit power of the photovoltaic module.

[0111] In some embodiments, for photovoltaic modules with inter-sheet gaps, the spacing between adjacent cells in a row of cells is 0 to 2 mm, specifically 0 mm, 0.5 mm, 1 mm, 2 mm, etc. For another type of photovoltaic module, multiple cells in a cell string are arranged in a shingled pattern, and the width of the overlapping area of ​​adjacent cells in each cell string is 0.3 mm to 2 mm, specifically 0.3 mm, 0.5 mm, 1 mm, 1.3 mm, 1.6 mm, 2 mm, etc. The inter-sheet spacing and string spacing of this type of photovoltaic module are both reduced, which can increase the unit power of the photovoltaic module.

[0112] In some possible implementations, the thickness of the packaging film of the photovoltaic module at the position corresponding to the bus bar 5 is smaller than the thickness of the packaging film at other positions. In this way, the force on the battery cell 1 can be evenly distributed, reducing the risk of hidden cracks in the battery cell 1.

[0113] In some possible implementations, in the thickness direction of the battery cell 1, there is a portion of back-side encapsulation material between the bus bar 5 and the first insulating layer 21. The portion of back-side encapsulation material between the bus bar 5 and the first insulating layer 21 can play a role in buffering contact between the bus bar 5 and the battery cell 1, reducing the risk of hidden cracks in the battery cell 1. If there is a second insulating layer 22 on the battery cell, there may also be a portion of back-side encapsulation material between the bus bar and the second insulating layer 22, with the same beneficial effect.

[0114] In some possible implementations, in the length direction of the busbar 5, at least one end of the busbar 5 is connected to the outermost first welding strip 41, and the end of the busbar 5 exceeds the outermost first welding strip 41 by more than 1 mm or covers at least 80% of the width of the outermost first welding strip 41. Specifically, it can exceed 1mm, 2mm, 3mm, 4mm, 5mm, etc., or cover 80%, 85%, 90%, 95%, 100%, etc. For example, Figure 2 , 4 As shown in , 6, the length direction of the bus bar 5 is perpendicular to the length direction of the first welding strip 41, and multiple first welding strips 41 are arranged at intervals along the length direction of the bus bar 5. The bus bar 5 is connected to one end or both ends of the multiple first welding strips 41. In the length direction of the bus bar 5, the end of the bus bar 5 exceeds the distance of the first welding strip 41 located at the outermost side by more than 1mm. In this way, it can be fully welded with the first welding strip 41 located at the outermost side, or a sufficient welding process window is reserved, and the excess length is convenient for connecting with other leads of the photovoltaic module.

[0115] Based on the photovoltaic module described in any of the above embodiments, an embodiment of the present invention further provides a method for preparing a photovoltaic module, comprising the following steps:

[0116] Step S100, printing insulating glue on the back side of the battery cell 1 at the position corresponding to the bus bar 5 to form a first insulating layer 21 arranged at intervals along the extension direction of the fine gate electrode of the battery cell 1. The first insulating layer 21 covers part of the length of the fine gate electrode of the second polarity to prevent conductive short circuits and protect the pad position to prevent overheating and short circuits caused by string welding. By optimizing the printing layout, the deviation and slippage of the welding strip to cause short circuits. It should be noted that in the case where the battery cell 1 has a second insulating layer 22, insulating glue is also printed in step S100 to form the second insulating layer 22. The printing patterns of the first insulating layer 21 and the second insulating layer 22 can refer to Figure 1 , Figure 9-11 The pattern can be printed at will.

[0117] Step S200, printing conductive glue on the back pad of the battery cell 1 to meet the welding requirements of the pad and the welding strip 4 and improve the welding performance and the conductive performance.

[0118] Step S300, layout and welding: lay the front cover plate and the front packaging film in sequence, and lay all the cells 1 of the photovoltaic module on the front packaging film, with the front of the cell 1 facing downward; lay and fix the welding strip 4, the insulating block 6 and the bus bar 5 on the back of the cell 1.

[0119] Among them, the first welding strip 41 is electrically connected to the fine gate electrode of the first polarity, and the second welding strip 42 is electrically connected to the fine gate electrode of the second polarity; the insulating blocks 6 and the first insulating layer 21 are alternately arranged along the extension direction of the fine gate electrode, and the insulating blocks 6 cover part of the fine gate electrode of the second polarity and part of the second welding strip 42; the bus bar 5 corresponds to the area of ​​the first insulating layer 21 and the insulating block 6, and the bus bar 5 extends along the length direction of the fine gate electrode; the bus bar 5 is electrically connected to the first welding strip 41, and the bus bar 5 and the second welding strip 42 are electrically isolated by the insulating block 6; the bus bar 5 and the fine gate electrode of the second polarity are electrically isolated by the alternately arranged insulating blocks 6 and the first insulating layer 21.

[0120] Step S400: laying a back packaging film and a back plate on the back of the battery cell 1 and laminating them to obtain a laminate.

[0121] When the above technical solution is adopted, a photovoltaic module with the same structure as any of the above embodiments can be obtained. The beneficial effects can be found in the above description of the photovoltaic module and will not be repeated here. In addition, after all the battery cells are laid on the front packaging cover plate, the preparation method uniformly lays welding strips, bus bars and insulating blocks on the back of the battery cells and fixes them together. Compared with the original method of first making a battery string, then arranging the battery string and welding the bus bars, it can simplify the layout and welding process, reduce the process difficulty, improve the production efficiency of photovoltaic modules, and improve the module yield.

[0122] Exemplarily, laying and fixing the welding ribbon 4, the insulating block 6 and the bus bar 5 on the back side of the battery cell 1 in step S300 specifically includes the following steps:

[0123] Step S311, first lay the welding tape 4 on the back of the battery cell 1. For example, the first welding tape 41 and the second welding tape 42 are laid on the back of the battery cell 1 respectively, the first welding tape 41 connects the positive electrode on the back of the previous battery cell 1 with the negative electrode on the back of the next battery cell 1, and the second welding tape 42 connects the negative electrode on the back of the previous battery cell 1 with the positive electrode on the back of the next battery cell 1, forming a series circuit. For another example, before laying the welding tape 4, a glue point for fixing the welding tape 4 can be set on the first battery cell 1, and then the welding tape is laid, and then the glue point is cured to fix the welding tape 4. It is also possible to first lay the welding tape on the battery cell 1, and then apply the glue point and cure it to fix the welding tape 4.

[0124] In this step, laser or infrared heating can be used to weld the welding ribbon 4 to the electrode on the battery cell 1. The welding ribbon 4 to the battery cell 1 and the welding ribbon 4 to the bus bar 5 can also be welded after laying the bus bar 5 in step S313.

[0125] Step S312: Lay an insulating block 6 on the back of the battery cell 1, and the insulating block 6 covers part of the second welding strip 42. For example, when the insulating block 6 is an insulating tape, the insulating tape is attached to the back of the battery cell 1 and is located above the second welding strip 42.

[0126] Step S313 : finally, a bus bar 5 is laid on the back of the battery cell 1 . The bus bar 5 is located above the insulating block 6 , and the bus bar 5 is welded to the first welding strip 41 .

[0127] The method of fixing the welding strip 4, the insulating block 6 and the bus bar 5 can facilitate the welding of the welding strip 4 and the battery cell 1, as well as the welding of the bus bar 5 and the first welding strip 41, thereby improving the welding strength. Since the stacking structure of the welding strip 4, the insulating block 6 and the bus bar 5 is simple, the welding point between the welding strip 4 and the bus bar 5 does not need to be bent, so that the first welding strip 41 can be in smooth contact with the battery cell 1, thereby reducing the risk of hidden cracks in the battery cell 1 caused by pressure on the first welding strip 41.

[0128] Exemplarily, another specific method of laying and fixing the welding ribbon 4, the insulating block 6 and the bus bar 5 on the back side of the battery cell 1 in step S300 includes the following steps:

[0129] Step S321 , firstly lay the bus bar 5 on the back side of the battery cell 1 .

[0130] Step S322 , laying an insulating block 6 on the back of the battery cell 1 . For example, when the insulating block 6 is an insulating tape, the insulating tape is attached to the back of the battery cell 1 and is located above the bus bar 5 .

[0131] Step S323, finally, the welding ribbon 4 is laid on the back of the battery cell 1, and the bus bar 5 and the second welding ribbon 42 are electrically isolated by the insulating block 6. For example, the first welding ribbon 41 is located above the bus bar 5 and welded to the bus bar 5, and the second welding ribbon 42 is located above the insulating block 6. At this time, the welding ribbon 4 is located at the top, and the welding effect of the bus bar 5 can be conveniently and quickly determined by naked eyes.

[0132] Furthermore, laying and fixing the soldering ribbon 4 on the back side of the battery cell 1 in step S300 also includes the steps of: firstly pre-fixing the soldering ribbon 4 using the fixing glue points on the battery cell 1, and then fixing the soldering ribbon 4 using infrared, laser or lamination.

[0133] For example, UV glue is applied to the outside of each large pad of all battery cells 1. The large pad refers to the pad with a larger area close to the edge of the battery cell 1, which is used to improve the welding strength with the welding strip 4. The diameter of the UV glue is 1mm to 3mm, and the edge of the UV glue is 0.5mm to 2mm away from the edge of the large pad. Then all the welding strips 4 are placed on the back of the battery cell 1, and the end of the welding strip 4 protrudes 0mm-2mm from the UV glue, and then a UV lamp is used to cure the welding strip 4 to pre-fix it. Finally, the welding strip 4 is fixed by infrared irradiation, laser welding or lamination temperature. The welding strip 4 is pre-fixed by fixing the glue point to ensure that the welding strip 4 is not easily displaced during the transfer and welding of the battery cell, thereby improving the welding accuracy of the welding strip 4.

[0134] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0135] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A photovoltaic module, characterized in that: It comprises a battery cell, a welding strip, a bus bar and an insulating block, wherein the back side of the battery cell has a fine grid electrode and a first insulating layer; The first welding strip is electrically connected to the fine grid electrode of the first polarity, and the second welding strip is electrically connected to the fine grid electrode of the second polarity; The insulating block is located on the back side of the battery cell, the insulating block and the first insulating layer are alternately arranged along the extension direction of the fine gate electrode, the insulating block covers part of the fine gate electrode of the second polarity and part of the second welding strip; the first insulating layer covers part of the fine gate electrode of the second polarity; The bus bar is located at a region on the back side of the battery cell corresponding to the first insulating layer and the insulating block, and the bus bar extends along the length direction of the fine gate electrode. The bus bar is electrically connected to the first welding strip, and the bus bar is electrically isolated from the second welding strip by the insulating block; the bus bar is electrically isolated from the fine gate electrode of the second polarity by the alternately arranged insulating blocks and the first insulating layer.

2. The photovoltaic module according to claim 1, characterized in that: The projections of the insulating blocks and the first insulating layer on the battery cells are alternately connected, or the projections of the insulating blocks and the first insulating layer on the battery cells have an overlapping area at the connection.

3. The photovoltaic module according to claim 2, characterized in that: Along the length direction of the fine gate electrode, the length of the overlapping area between the projection of the insulating block and the first insulating layer on the battery cell is greater than 0.5 mm.

4. The photovoltaic module according to claim 1, characterized in that: The back side of the battery cell also has a second insulating layer, the first insulating layer and the second insulating layer are alternately arranged along the length direction of the bus bar, and the second insulating layer covers the fine gate electrode of the first polarity; the insulating block is correspondingly stacked above the second insulating layer.

5. The photovoltaic module according to claim 4, characterized in that: Along the length direction of the busbar, the difference between the length of the first insulating layer and the length of the second insulating layer is less than or equal to 2 mm; and / or, along the width direction of the busbar, a difference between a width of the first insulating layer and a width of the second insulating layer is less than or equal to 2 mm; and / or, along the width direction of the busbar, the first insulating layer and the second insulating layer intersect; And / or, the first insulating layer and the second insulating layer are made of the same material and have the same thickness, and are printed on the battery cell simultaneously; And / or, the first insulating layer and the second insulating layer are transparent adhesive layers; and / or, along the length direction of the busbar, the length of the insulating block is 0.5 mm to 4 mm longer than the length of the second insulating layer stacked with the insulating block; And / or, the pattern of the second insulating layer on all the cells in the photovoltaic module is the same and the pattern of the first insulating layer on all the cells in the photovoltaic module is the same.

6. The photovoltaic module according to claim 1, characterized in that: In the length direction of the busbar, the end of the insulating region composed of the first insulating layer and the insulating block exceeds the end of the busbar by a distance of 1 mm to 5 mm; In the width direction of the busbar, the distance that the side edge of the insulating region composed of the first insulating layer and the insulating block exceeds the side edge of the busbar is 1 mm to 5 mm; Furthermore, in the thickness direction of the battery cell, the insulation distance between the bus bar and the second welding strip and the fine grid electrode of the second polarity is greater than or equal to 10 μm.

7. The photovoltaic module according to claim 1, characterized in that: The insulating block is a tape, and the tape is pasted on the battery cell; And / or, the insulating block is a rectangular insulating block.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The bus bar is located at a non-edge position of the battery cell; or, The bus bar is located at an edge of the battery cell; or, The busbar covers part of the previous battery cell and part of the next battery cell; the covering width of the busbar on the previous battery cell is 1mm to 5mm, the covering width of the busbar on the next battery cell is 1mm to 5mm, and the spacing between the previous battery cell and the next battery cell is 0 to 2mm.

9. The photovoltaic module according to any one of claims 1 to 7, characterized in that: Along the width direction of the bus bar, the connection length between the bus bar and a first welding strip is greater than or equal to 20% of the width of the bus bar.

10. The photovoltaic module according to any one of claims 1 to 7, characterized in that: Along the width direction of the busbar, the welding strips fixed on the busbar are aligned or connected on the busbar.

11. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The photovoltaic module further comprises a buffer film located between the bus bar and the back packaging film of the photovoltaic module.

12. The photovoltaic module according to claim 11, characterized in that: The thickness of the buffer film is 200 μm to 1000 μm, and / or the width of the buffer film is 0 to 100 mm wider than the width of the busbar, and / or the length of the buffer film is 0 to 5 mm longer than the length of the busbar, and / or the material of the buffer film is POE, EPE or EVA.

13. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The bus bar is located on the side of the first welding strip and the second welding strip away from the battery cell, and the height difference between the position of the bus bar corresponding to the first welding strip and the position corresponding to the second welding strip is less than or equal to 100mm; and the cross-section of the welding strips is rectangular.

14. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The distance between the cover plate and the back plate of the photovoltaic module is A, the sum of the thicknesses of the battery cell, the fine grid electrode and the welding strip is B, and B accounts for less than 79% of A.

15. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The battery cell comprises m columns, wherein one column comprises two or more battery strings; the spacing between adjacent battery cells in one column is 0 to 2 mm, or the plurality of battery cells in the battery string are arranged in a shingled pattern, and the width of the overlapping region of adjacent battery cells in each battery string is 0.3 mm to 2 mm; And / or, the difference in the minimum distance between the battery group composed of the battery cells in the photovoltaic module and the edges of the cover plate of the photovoltaic module is less than 0.5 mm.

16. The photovoltaic module according to any one of claims 1 to 7, characterized in that: The thickness of the packaging film of the photovoltaic module at the position corresponding to the bus bar is smaller than the thickness of the packaging film at other positions; and / or, In the thickness direction of the battery cell, there is a portion of back side packaging material between the bus bar and the first insulating layer.

17. The photovoltaic module according to any one of claims 1 to 7, characterized in that: In the length direction of the busbar, at least one end of the busbar is connected to the outermost first welding strip, and the end of the busbar exceeds the outermost first welding strip by more than 1 mm or covers at least 80% of the width of the outermost first welding strip.

18. A method for preparing a photovoltaic module, characterized in that: include: Printing insulating glue at a position corresponding to the bus bar on the back side of the battery cell to form a first insulating layer arranged at intervals along the extension direction of the fine gate electrode of the battery cell, wherein the first insulating layer covers a portion of the fine gate electrode of the second polarity; Printing conductive glue on the back pad of the battery cell; Layout and welding: Lay the front cover plate and the front packaging film in sequence, and lay all the cells of the photovoltaic module on the front packaging film, with the front of the cell facing downward; lay and fix the welding strip, the insulating block and the bus bar on the back of the cell; wherein the first welding strip is electrically connected to the fine grid electrode of the first polarity, and the second welding strip is electrically connected to the fine grid electrode of the second polarity; the insulating block and the first insulating layer are alternately arranged along the extension direction of the fine grid electrode, and the insulating block covers part of the fine grid electrode of the second polarity and part of the second welding strip; the bus bar corresponds to the area of ​​the first insulating layer and the insulating block, and the bus bar extends along the length direction of the fine grid electrode; the bus bar is electrically connected to the first welding strip, and the bus bar is electrically isolated from the second welding strip by the insulating block; the bus bar is electrically isolated from the fine grid electrode of the second polarity by the alternately arranged insulating blocks and the first insulating layer; A back side packaging adhesive film and a back plate are laid on the back side of the battery cell and laminated.

19. The method for preparing a photovoltaic module according to claim 18, characterized in that: Laying and fixing the welding strip, the insulating block and the bus bar on the back of the battery cell includes: First, the welding strip is laid on the back of the battery cell; then, the insulating block is laid on the back of the battery cell, and the insulating block covers part of the second welding strip; finally, the bus bar is laid on the back of the battery cell; Alternatively, the bus bar is first laid on the back of the battery cell, and then the insulating block is laid on the back of the battery cell; finally, the welding strip is laid on the back of the battery cell, and the bus bar and the second welding strip are electrically isolated by the insulating block.

20. The method for preparing a photovoltaic module according to claim 19, characterized in that: Laying and fixing the soldering tape on the back of the battery cell comprises: firstly pre-fixing the soldering tape by using the fixing glue points on the battery cell, and then fixing the soldering tape by using infrared, laser or lamination.

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