Photovoltaic module and preparation method thereof

Abstract

The invention discloses a photovoltaic module and a preparation method thereof, and relates to the technical field of photovoltaic module manufacturing, and the method specifically comprises the steps: a backboard, a rear adhesive film, a battery array, a front adhesive film and a cover plate are stacked from bottom to top; wherein the battery array comprises a plurality of groups of battery strings arranged in parallel and bonding parts arranged on at least one side of each battery string; wherein each battery string comprises a plurality of battery pieces which are connected in series and a plurality of welding strips which are connected with two adjacent battery pieces; in the battery string, the bonding parts are in lap joint with two adjacent edges of two adjacent battery pieces; and the bonding parts and the plurality of welding strips on the battery piece are arranged at intervals. According to the embodiment of the invention, the two adjacent battery pieces in the battery string are fixed by arranging the bonding parts in lap joint with the bonding parts on the two adjacent edges of the two adjacent battery pieces, so that the situation that the adjacent battery pieces move in opposite directions due to gaps between the battery pieces is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of photovoltaic module manufacturing, and in particular to a photovoltaic module and a preparation method thereof. Background Art

[0002] In existing photovoltaic modules, a battery string is usually obtained by connecting multiple battery cells in series through welding with a welding ribbon, that is, the welding ribbon is the only connecting component between adjacent battery cells. Specifically, after the two ends of the welding ribbon are respectively welded to two adjacent battery cells, there will still be a partial gap between the two battery cells, so that during the subsequent lamination process, the welding ribbon located in the gap is in an active state, causing the two adjacent battery cells to move towards each other, resulting in hidden cracks on the edges of the battery cells, thereby affecting the reliability of the photovoltaic module. Summary of the invention

[0003] In view of this, an embodiment of the present invention provides a photovoltaic module and a method for preparing the same, by providing an adhesive portion on at least one side of the battery string, and allowing the adhesive portion to overlap two adjacent edges of two adjacent battery cells, and further using the adhesive portion to fix two adjacent battery cells in the battery string, thereby avoiding the situation where the adjacent battery cells move toward each other due to the gap between the battery cells. At the same time, setting the adhesive portion and the welding strip at a distance will not affect the welding strip, and the reliability of the photovoltaic module is further improved on the basis of welding the welding strip.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] In a first aspect, the present invention provides a photovoltaic module, comprising: a back plate, a rear adhesive film, a battery array, a front adhesive film and a cover plate stacked from bottom to top; wherein the battery array comprises: a plurality of battery strings arranged in parallel and an adhesive portion arranged on at least one side of each of the battery strings; wherein each of the battery strings comprises a plurality of battery cells connected in series, and a plurality of welding strips connecting two adjacent battery cells; in the battery string, the adhesive portion overlaps two adjacent edges of two adjacent battery cells; the adhesive portion is spaced apart from the plurality of welding strips on the battery cells.

[0006] Optionally, the thickness of the adhesive portion is greater than the thickness of the battery cell; and / or the material of the adhesive portion is at least one of hot melt adhesive, soft acrylic glue, silicone-based glue, and epoxy glue.

[0007] Optionally, when the material of the bonding portion is hot melt adhesive, the melting point of the hot melt adhesive is not less than 140°C.

[0008] Optionally, the interval between two adjacent battery cells is -0.8 mm to +0.8 mm; and / or the interval between two adjacent battery strings is 0.5 mm to 1.0 mm.

[0009] Optionally, the width of the bonding portion is 1 mm to 5 mm; and / or the thickness of the bonding portion is 0.10 mm to 0.30 mm.

[0010] Optionally, the multiple battery cells in each of the battery strings are arranged in a straight line.

[0011] Optionally, the bonding portion is provided on both sides of the battery string in the thickness direction; in the case where the battery string is a shingled or welded structure, the bonding portion on each side abuts against the main surface of one of the battery cells and the side surface of another adjacent battery cell.

[0012] In a second aspect, the present invention provides a method for preparing a photovoltaic module, comprising: step 1, connecting a plurality of battery cells in series into a group of battery strings using welding tapes; step 2, for each group of the battery strings: applying an adhesive coating on the battery cells; wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells, and the adhesive coating and the plurality of welding tapes on the battery string are applied at intervals; step 3, curing the adhesive coating to obtain a battery string with an adhesive portion; step 4, stacking a backplane, a rear adhesive film, a plurality of groups of battery strings with an adhesive portion, a front adhesive film, and a cover plate from bottom to top, and preparing the photovoltaic module through a lamination process.

[0013] The technical solution of the first aspect of the above invention has the following advantages or beneficial effects: by providing an adhesive portion on at least one side of the battery string and allowing the adhesive portion to overlap two adjacent edges of two adjacent battery cells, the two adjacent battery cells in the battery string are further fixed by the adhesive portion, thereby avoiding the situation where the adjacent battery cells move toward each other due to the gap between the battery cells. At the same time, setting the adhesive portion and the welding strip at a distance will not affect the welding strip, and the reliability of the photovoltaic module is further improved on the basis of welding the welding strip. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0015] Figure 1 is a schematic structural diagram of a battery string in a photovoltaic module according to an embodiment of the present invention;

[0016] Figure 2 This is a structural diagram of a stacked-welded battery string without a bonding portion in the prior art;

[0017] Figure 3 It is a diagram showing the arrangement relationship of multiple battery cells in a battery string from a top-down perspective in the prior art;

[0018] Figure 4is a structural diagram of a battery string in which an adhesive portion is provided on the front side of the battery string according to an embodiment of the present invention;

[0019] Figure 5 is a structural diagram of a battery string in which an adhesive portion is provided on the front side of the battery string according to an embodiment of the present invention;

[0020] Figure 6 is the stress condition of the bonding portion located on the front side of the battery cell according to an embodiment of the present invention;

[0021] Figure 7 is the stress condition of the bonding portion located on the back side of the battery cell according to an embodiment of the present invention;

[0022] Figure 8 is the stress condition of the bonding parts located on both sides of the battery cell according to an embodiment of the present invention;

[0023] Fig. 9 is a setting position of the bonding portion according to an embodiment of the present invention;

[0024] Fig.10 It is a schematic flow chart of a method for preparing a photovoltaic module according to an embodiment of the present invention.

[0025] The reference numerals are as follows:

[0026] 1-battery string; 11-battery cell; 12-solder strip; 2-bonding part. DETAILED DESCRIPTION

[0027] A solar cell is a photoelectric semiconductor sheet that uses sunlight to generate electricity directly. It is also called a "solar chip" or "photovoltaic cell". As long as it is illuminated by light that meets certain illumination conditions, it can instantly output voltage and generate current in the presence of a circuit. In physics, it is called solar photovoltaic (PV), or photovoltaic for short. In order to conveniently and clearly describe the method for preparing a solar cell and the solar cell of the present invention, the following exemplary embodiments of the present invention are described in conjunction with the accompanying drawings, which include various details of the embodiments of the present invention to facilitate understanding, and they should be considered as merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0028] In one embodiment of the present invention, this embodiment provides a photovoltaic module, such as Figure 1As shown, the photovoltaic module includes: a back plate, a rear adhesive film, a battery array, a front adhesive film and a cover plate stacked from bottom to top; wherein, the battery array includes: a plurality of battery strings 1 arranged in parallel and an adhesive portion 2 arranged on at least one side of each battery string 1; wherein, each battery string 1 includes a plurality of battery cells 11 connected in series, and a plurality of welding strips 12 connecting two adjacent battery cells 11; in the battery string 1, the adhesive portion 2 overlaps two adjacent edges of two adjacent battery cells 11; the adhesive portion 2 is spaced apart from the plurality of welding strips 12 on the battery cells 11.

[0029] Since the present invention is mainly aimed at improving the battery string, Figure 1 The back plate, rear film, front film and cover plate are not shown in the figure, and the positional relationship between the battery string 1, the battery cell 11, the welding strip 12 and the bonding part 2 is mainly described. Specifically, Figure 1 A preferred embodiment of the present invention is shown, that is, a plurality of adhesive portions 2 are provided on both sides of the battery string 1, that is, the plurality of battery cells 11 on the battery string 1 are fixed together by the plurality of adhesive portions 2.

[0030] Below Figures 2 to 5 The photovoltaic module provided by the present invention is specifically described, wherein: Figure 2 The structure diagram of the stacked-welded battery string without the bonding part 2 in the prior art is shown. Figure 3 The diagram shows the arrangement relationship of multiple battery cells 11 in the battery string 1 from a top view; Figure 4 The structure diagram of a battery string in which a bonding portion 2 is provided on the front side of a battery string 1 according to an embodiment of the present invention is shown. Figure 5 The structure diagram of a battery string in which an adhesive portion 2 is provided on the back side of a battery string 1 according to an embodiment of the present invention is shown.

[0031] from Figure 2 and Figure 3It can be seen that when the adhesive portion 2 is not provided, multiple adjacent battery cells 11 are electrically connected only through the welding strip 12, that is, for one welding strip 12: the left end of the welding strip 12 is connected to the back of a battery cell 11, and the right end of the welding strip 12 is connected to the front of another battery cell 11. In this case, the spacing between adjacent battery cells 11 usually needs to be greater than 0.8 mm to avoid hidden cracks on the edges of the battery cells 11 after the adjacent battery cells 11 move toward each other during the lamination process. At the same time, in the string welding direction, since the welding strips 12 at the connection between each battery cell 11 are actually in an active state, it is difficult for multiple battery cells 11 to be aligned in a straight line, and only a concave and convex battery string 1 can be formed. The problem caused by this is that when preparing a battery array, multiple parallel battery strings 1 cannot be too close, and usually need to be greater than 1.5 mm, because if the string spacing is too small, the battery cells 11 on adjacent battery strings 1 will come into contact, which will cause a short circuit problem. It can be seen that in the photovoltaic modules of the prior art, both the spacing between adjacent cells 11 in the same cell string 1 and the string spacing between multiple parallel arranged cell strings 1 have certain limitations, which greatly affects the high-density performance of high-density modules.

[0032] from Figure 4 and Figure 5 It can be seen that the bonding portion 2 arranged on one side of the battery cell 11 in the embodiment of the present invention is always arranged facing the adjacent battery cell 11, so that the purpose of overlapping the adjacent edges of two adjacent battery cells 11 can be achieved. In a further optional embodiment, bonding portions 2 are arranged on both sides of the battery string 1 in the thickness direction; in the case where the battery string is a shingled or welded structure, the bonding portion 2 on each side abuts against the main surface of a battery cell 11 and the side surface of another adjacent battery cell 11. Figure 4 Taking the three battery cells 11 connected in series in the example, since the three battery cells 11 are a stacked welding structure, that is, the right end of the battery cell on the left is arranged above the left end of the battery cell on the right, the bonding part 2 arranged on the front side of the battery string 1 is arranged on the left end of the battery cell 11 on the right, and the bottom surface of the bonding part 2 abuts against the upper surface of the battery cell 11 on the right, and the side surface of the bonding part 2 abuts against the right surface of the battery cell 11 on the left. Similarly, for Figure 5 In the three battery cells 11 , the adhesive portion 2 disposed on the back side of the battery string 1 is disposed at the right end portion of the left battery cell 11 .

[0033] It is understandable that the bonding portion 2 is provided to ensure that there is no relative movement between adjacent cells 11, so the cell spacing between multiple cells 11 in the cell string 1 can be set smaller to further meet the high density requirements of the photovoltaic module. In an optional embodiment, the cell spacing between two adjacent cells 11 is -0.8mm to +0.8mm, such as -0.8mm, -0.4mm, 0mm, +0.4mm, +0.8mm, etc. Among them, when there is overlap between adjacent cells 11, the cell spacing is a negative value.

[0034] At the same time, under the fixing effect of the adhesive portion 2, the battery cell 11 is also prevented from longitudinal displacement, so it is preferred that the multiple battery cells 11 in each battery string 1 are arranged in a straight line. Through the above arrangement, the string spacing between multiple parallel battery strings 1 in the battery array can be further shortened. In an optional embodiment, the string spacing between two adjacent battery strings 1 is 0.5 mm ~ 1.0 mm, such as 0.5 nm, 0.6 nm, 0.7 nm, 0.8 nm, 0.9 nm, 1.0 nm, etc.

[0035] In an optional embodiment, the material of the bonding part 2 is at least one of hot melt adhesive, soft acrylic adhesive, silicone-based adhesive, and epoxy adhesive. Considering that the bonded battery string 1 needs to undergo a lamination process to prepare a complete photovoltaic module, the material of the bonding part 2 should be selected to be a material that does not react with the front adhesive film and / or the rear adhesive film during the lamination process to avoid affecting the lamination process.

[0036] In a further optional embodiment, since the lamination process usually needs to be heated to 145° C., when the material of the bonding portion 2 is hot melt adhesive, the melting point of the hot melt adhesive is not less than 140° C. That is, the melting point of the hot melt adhesive is slightly lower than the lamination temperature, so that the hot melt adhesive may be partially deformed during the lamination process, but will not be completely melted, and will not be mixed with the front adhesive film and / or the rear adhesive film. At the same time, it can also provide partial support for the battery cell 11 to avoid hidden cracks in the battery cell 11 during the lamination process.

[0037] It is understandable that during the lamination process, the laminator will provide longitudinal pressure to squeeze the stacked backplane, rear film, battery array, front film and cover plate into one. Therefore, during the lamination process, the battery array will be subjected to pressure from above and below. Since the welding strips 12 are provided at some positions between the battery cells 11, compared with the areas without the welding strips 12, under the same pressure, the welding strips 12 are more likely to crush the battery cells 11, thereby causing hidden cracks in the battery cells 11. Therefore, in the embodiment of the present invention, another function of providing the adhesive portion 2 is to provide a buffer for the battery cells 11 during the lamination process, which can be specifically as follows: Figures 6 to 8 As shown. Among them, Figure 6 The figure shows the stress of the bonding portion 2 located on the front side of the battery cell 11. Figure 7 The figure shows the stress of the bonding portion 2 on the back side of the battery cell 11. Figure 8 The figure shows the stress of the adhesive part 2 located on both sides of the battery cell 11. It should be noted that, in order to achieve this effect, in an optional embodiment, the thickness of the adhesive part 2 is greater than the thickness of the battery cell 11.

[0038] from Figure 6 and Figure 8 It can be seen that when the adhesive portion 2 is located on the front side of the battery cell 11, the laminator will apply pressure from top to bottom to the battery cell 11. If there is no adhesive portion 2, there will be downward pressure between the right end of the battery cell 11 on the left and the left end of the battery cell 11 on the right. When the pressure is large enough, due to the presence of the welding strip 12, the right end of the left battery cell 11 and the left end of the right battery cell 11 will cause hidden cracks. When the adhesive portion 2 is set, the pressure from top to bottom will be applied to the thicker adhesive portion 2 in advance, causing the adhesive portion 2 to partially deform and transfer part of the downward force to the battery cell 11 on the right, increasing the gap between adjacent battery cells 11, which reserves enough lamination space for the welding strip 12 to avoid hidden cracks in the hungry battery cell 11. Figure 7 and Figure 6 The principle is the same as that of the laminator. When the adhesive portion 2 is located on the back side of the battery cell 11, the laminator applies a force from bottom to top to the battery cell 11, so that the adhesive portion 2 partially deforms and transmits part of the upward force to the battery cell 11 on the left side, thereby increasing the gap between adjacent battery cells 11. It can be understood that when Figure 8 As shown, when the adhesive portions 2 are provided on both sides of the battery cell 11 , maximum protection of the battery cell 11 is achieved.

[0039] In a further optional embodiment, the thickness of the adhesive portion 2 can be set to 0.10mm~0.30mm, for example 0.10mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, etc., to ensure that the thickness of the adhesive portion 2 is slightly higher than the thickness of the battery cell 11. The thickness does not need to be too large, which will cause unnecessary waste of resources and affect the overall performance of the photovoltaic module.

[0040] It is understandable that when the adhesive portion 2 is not needed to fix the multiple battery cells 11 in the battery string 1, and only the hidden crack problem of the battery cells needs to be solved, the side of the adhesive portion 2 may not abut against the side of the adjacent battery cell 11. In an optional embodiment, the adhesive portion 2 is set on the main surface of the battery cell 11 at a distance of 1 mm to 15 mm from the adjacent battery cell, such as 1 mm, 5 mm, 8 mm, 10 mm, 12 mm, 15 mm, etc.

[0041] In addition, in order to ensure the bonding performance of the bonding portion 2, in an optional embodiment, the width of the bonding portion 2 is 1 mm to 15 mm, such as 1 mm, 3 mm, 8 mm, 10 mm, 12 mm, 15 mm, etc. It can be understood that the larger the contact area between the bonding portion 2 and the battery cell 11, the better the bonding performance, so the thickness and width of the bonding portion 2 should not be too small, which will easily affect the bonding performance.

[0042] The setting position of the bonding part 2 can be as follows: Fig. 9 As shown, the arrangement direction of the soldering tape 12 is the width direction of the bonding portion 2. Fig. 9 It can be seen that by arranging the adhesive portion 2 and the soldering tape 12 at intervals, the adhesive effect can be ensured as much as possible without affecting the soldering tape 12 , and the positions of adjacent battery cells 11 are aligned after bonding.

[0043] In summary, the photovoltaic module provided by the embodiment of the present invention, by providing an adhesive portion on at least one side of the battery string, and allowing the adhesive portion to overlap two adjacent edges of two adjacent battery cells, further uses the adhesive portion to fix two adjacent battery cells in the battery string, thereby avoiding the situation where the adjacent battery cells move toward each other due to the gap between the battery cells. At the same time, setting the adhesive portion and the welding strip at a distance will not affect the welding strip, and the reliability of the photovoltaic module is further improved on the basis of welding the welding strip.

[0044] In one embodiment of the present invention, Fig.10 As shown, this embodiment provides a method for preparing a photovoltaic module, and the preparation method may include the following steps:

[0045] Step S1001, multiple battery cells 11 are connected in series into a battery string 1 using a welding ribbon 12;

[0046] Step S1002, for each battery string 1: applying adhesive coating on the battery cells 11; wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells 11, and the adhesive coating is applied alternately with the plurality of welding strips 12 on the battery string 1;

[0047] Step S1003, curing the adhesive coating to obtain a battery string 1 having an adhesive portion 2;

[0048] Step S1004 , stacking the back sheet, the rear adhesive film, a plurality of groups of battery strings 1 with adhesive portions 2 , the front adhesive film, and the cover sheet from bottom to top, and preparing a photovoltaic module through a lamination process.

[0049] Among them, step S1001 is a conventional welding process of the welding strip 12. The present invention does not elaborate on the specific process parameters of the welding. The embodiment of the present invention performs steps S1002 and S1003 on the battery string 1 welded with the welding strip 12, thereby realizing the preparation process of the bonding part 2.

[0050] In an optional embodiment, the adhesive coating is at least one of hot melt adhesive, soft acrylic adhesive, silicone-based adhesive, and epoxy adhesive. There are some differences in the curing process for adhesive coatings of different materials. For example, when the adhesive coating is hot melt adhesive, the adhesive coating can be quickly cured by cooling.

[0051] For the lamination process in step S1004, in an optional embodiment, the lamination temperature of the lamination process is 140°C to 150°C, such as 140°C, 145°C, 150°C, etc. It is understandable that in the lamination process, it is necessary to avoid chemical reaction or mixing of the adhesive coating with the front adhesive film and / or the rear adhesive film as much as possible, so the lamination temperature in the lamination process should correspond to the melting point of the adhesive coating, and preferably not greater than the melting point of the adhesive coating.

[0052] In addition, after the adhesive coating is cured, the volume may partially change, such as shrinking, etc. Therefore, for the coating width and coating thickness of the adhesive coating, in an optional embodiment, the coating width of the adhesive coating is 1mm~15mm; for example, 1mm, 3mm, 8mm, 10mm, 12mm, 15mm, etc.; the coating thickness of the adhesive coating is 0.10mm~0.30mm, such as 0.10mm, 0.15mm, 0.20mm, 0.25mm, 0.30mm, etc.

[0053] In summary, the method for preparing a photovoltaic module provided by an embodiment of the present invention applies an adhesive coating on a battery string 1 welded with a welding strip 12 and solidifies it, so that the formed adhesive portion 2 overlaps the two adjacent edges of two adjacent battery cells, and the two adjacent battery cells in the battery string are fixed by the adhesive portion, thereby avoiding the situation where the adjacent battery cells move toward each other due to the gap between the battery cells. At the same time, setting the adhesive portion and the welding strip at intervals will not affect the welding strip, and the reliability of the photovoltaic module is further improved on the basis of welding the welding strip.

[0054] Example 1

[0055] A method for preparing a photovoltaic module

[0056] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0057] Step b, for each battery string: applying an adhesive coating on one side of the front of the battery; wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells, and the adhesive coating is applied alternately with multiple welding strips on the battery string; wherein the coating width is 8 mm, the coating thickness is 0.20 mm, and the coating material is hot melt adhesive;

[0058] Step c, arranging the plurality of battery cells on the battery string in a straight line, and curing the adhesive coating to obtain a battery string with an adhesive portion;

[0059] Step d: stacking the back sheet, the rear adhesive film, a plurality of battery strings with adhesive portions, the front adhesive film, and the cover sheet from bottom to top to prepare a photovoltaic module through a lamination process.

[0060] Example 2

[0061] A method for preparing a photovoltaic module

[0062] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0063] Step b, for each battery string: applying an adhesive coating on one side of the back of the battery; wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells, and the adhesive coating is applied alternately with multiple welding strips on the battery string; wherein the coating width is 8 mm, the coating thickness is 0.20 mm, and the coating material is hot melt adhesive;

[0064] Step c, arranging the plurality of battery cells on the battery string in a straight line, and curing the adhesive coating to obtain a battery string with an adhesive portion;

[0065] Step d: stacking the back sheet, the rear adhesive film, a plurality of battery strings with adhesive portions, the front adhesive film, and the cover sheet from bottom to top to prepare a photovoltaic module through a lamination process.

[0066] Example 3

[0067] A method for preparing a photovoltaic module

[0068] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0069] Step b, for each battery string: applying adhesive coating on the front side and the back side of the battery; wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells, and the adhesive coating is applied alternately with multiple welding strips on the battery string; wherein the coating width is 8 mm, the coating thickness is 0.20 mm, and the coating material is hot melt adhesive;

[0070] Step c, arranging the plurality of battery cells on the battery string in a straight line, and curing the adhesive coating to obtain a battery string with an adhesive portion;

[0071] Step d: stacking the back sheet, the rear adhesive film, a plurality of battery strings with adhesive portions, the front adhesive film, and the cover sheet from bottom to top to prepare a photovoltaic module through a lamination process.

[0072] Example 4

[0073] A method for preparing a photovoltaic module

[0074] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0075] Step b, for each battery string: applying an adhesive coating on the front side of the battery; wherein the adhesive coating does not overlap with adjacent battery cells, and the adhesive coating is applied alternately with multiple welding strips on the battery string; wherein the coating width is 8 mm, the coating thickness is 0.20 mm, and the coating material is hot melt adhesive;

[0076] Step c, arranging the plurality of battery cells on the battery string in a straight line, and curing the adhesive coating to obtain a battery string with an adhesive portion;

[0077] Step d: stacking the back sheet, the rear adhesive film, a plurality of battery strings with adhesive portions, the front adhesive film, and the cover sheet from bottom to top to prepare a photovoltaic module through a lamination process.

[0078] Example 5

[0079] A method for preparing a photovoltaic module

[0080] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0081] Step b, for each battery string: applying adhesive coating on the front side and the back side of the battery; wherein the adhesive coating does not overlap with adjacent battery cells, and the adhesive coating is applied alternately with multiple welding strips on the battery string; wherein the coating width is 8 mm, the coating thickness is 0.20 mm, and the coating material is hot melt adhesive;

[0082] Step c, arranging the plurality of battery cells on the battery string in a straight line, and curing the adhesive coating to obtain a battery string with an adhesive portion;

[0083] Step d: stacking the back sheet, the rear adhesive film, a plurality of battery strings with adhesive portions, the front adhesive film, and the cover sheet from bottom to top to prepare a photovoltaic module through a lamination process.

[0084] Comparative Example

[0085] A method for preparing a photovoltaic module

[0086] Step a, connecting a plurality of battery cells in series into a battery string using a welding ribbon;

[0087] Step b: stacking the back sheet, the rear adhesive film, multiple groups of battery strings, the front adhesive film, and the cover sheet from bottom to top to obtain a photovoltaic module through a lamination process.

[0088] By testing the crack points of the photovoltaic modules prepared in the above-mentioned embodiments and comparative examples, the test results are as follows:

[0089]

[0090] It can be seen from the above test results that the photovoltaic module prepared by the preparation method provided by the embodiment of the present invention can effectively reduce the number of hidden crack points on the battery cell. Among them, when the bonding part is not set, the number of hidden crack points is 7. When the bonding part is set on one side of the battery cell, it can be seen from the comparison between Example 1 and Example 4, and Example 3 and Example 5 that regardless of whether the bonding part overlaps with the side of the adjacent battery cell, the purpose of reducing hidden cracks can be achieved, that is, the number of hidden crack points is reduced to 1-2, and the effect is very obvious. Furthermore, when the bonding part is set on both sides of the battery cell, the hidden crack points are effectively eliminated, indicating that the situation of hidden cracks in the battery cell is basically avoided.

[0091] The introduction provided in the above steps is only used to help understand the structure, method and core idea of ​​the present invention. For ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also belong to the scope of protection of the claims of the present invention.

Claims

1. A photovoltaic module, characterized in that: include: A back plate, a rear film, a battery array, a front film and a cover plate are stacked from bottom to top; The battery array comprises: a plurality of battery strings (1) arranged in parallel, and a bonding portion (2) arranged on at least one side of each of the battery strings (1); Each of the battery strings (1) comprises a plurality of battery cells (11) connected in series, and a plurality of welding strips (12) connecting two adjacent battery cells (11); In the battery string (1), the bonding portion (2) overlaps two adjacent edges of two adjacent battery sheets (11); The bonding portion (2) is arranged at intervals from the plurality of welding strips (12) on the battery cell (11).

2. The photovoltaic module according to claim 1, characterized in that: The thickness of the bonding portion (2) is greater than the thickness of the battery cell (11); and / or, The material of the bonding portion (2) is at least one of hot melt glue, soft acrylic glue, silicone-based glue, and epoxy glue.

3. The photovoltaic module according to claim 2, characterized in that: When the material of the bonding portion (2) is hot melt adhesive, the melting point of the hot melt adhesive is not less than 140°C.

4. The photovoltaic module according to claim 1, characterized in that: The distance between two adjacent battery cells (11) is -0.8 mm to +0.8 mm; and / or, The string spacing between two adjacent battery strings (1) is 0.5 mm to 1.0 mm.

5. The photovoltaic module according to claim 1, characterized in that: The width of the bonding portion (2) is 1 mm to 15 mm; and / or, The thickness of the bonding portion (2) is 0.10 mm to 0.30 mm.

6. The photovoltaic module according to claim 1, characterized in that: The multiple battery cells (11) in each battery string (1) are arranged in a straight line.

7. The photovoltaic module according to claim 1, characterized in that: The bonding parts (2) are arranged on both sides of the battery string (1) in the thickness direction; In case the battery string is a shingled or welded structure, The bonding portion (2) located on each side abuts against the main surface of one of the battery cells (11) and abuts against the side surface of another adjacent battery cell (11).

8. A method for preparing a photovoltaic module, characterized in that: include: Step 1, connecting a plurality of battery cells (11) in series into a battery string (1) using a welding ribbon (12); Step 2, for each group of the battery strings (1): applying an adhesive coating on the battery cells (11); wherein the adhesive coating overlaps two adjacent edges of two adjacent battery cells (11), and the adhesive coating is applied alternately to the plurality of welding strips (12) on the battery string (1); Step 3, curing the adhesive coating to obtain a battery string (1) having an adhesive portion (2); Step 4, stacking the back sheet, the rear adhesive film, a plurality of groups of battery strings (1) having adhesive portions (2), the front adhesive film, and the cover sheet from bottom to top, and preparing the photovoltaic module through a lamination process.

9. The preparation method according to claim 8, characterized in that: The lamination temperature of the lamination process is 140°C to 150°C; and / or, The adhesive coating is at least one of hot melt adhesive, soft acrylic adhesive, silicone-based adhesive, and epoxy adhesive.

10. The preparation method according to claim 8, characterized in that: The coating width of the adhesive coating is 1 mm to 15 mm; and / or, The coating thickness of the adhesive coating is 0.10 mm to 0.30 mm.

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