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 modules. The photovoltaic module comprises a battery string, an adhesive film and an isolation part, wherein the battery string comprises a plurality of battery pieces and a plurality of welding strips for connecting the battery pieces in series; and the isolation part covers the end part of the welding strip, so that the end part of the welding strip is isolated from the adhesive film. According to the embodiment, the isolation part covering the end part of the welding strip is arranged between the adhesive film and the battery piece, so that direct contact between the end part of the welding strip and the adhesive film is effectively isolated, and the phenomenon that the adhesive film of the photovoltaic module becomes yellow due to the reaction between the welding strip and components in the adhesive film is avoided.

Description

Technical Field

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

[0002] The soldering tape connecting the cells in the photovoltaic module is mainly used to collect the current generated by the cells, and the adhesive film is mainly used to protect the photovoltaic module and reduce the impact of environmental factors. When the soldering tape with flux comes into contact with the adhesive film containing benzene ring substances, the benzene ring reacts with hydroxyl and peroxide in a hot oxygen environment to generate benzoquinone substances, causing the adhesive film to turn yellow. Especially for UV cut-off adhesive films, due to the presence of UV absorbers, more chemical substances participate in the reaction, making the yellowing phenomenon of the adhesive film more obvious.

[0003] Since the new cross-section of the solder ribbon does not have a protective layer, the solder at the end of the solder ribbon is directly exposed and in contact with the adhesive film. The metal in the solder catalyzes the above reaction, causing the corresponding adhesive film around the end of the solder ribbon to turn yellow more obviously. The yellowing of the adhesive film not only affects the aesthetics of the photovoltaic module, but may also reduce the light transmittance of the adhesive film, further reducing the photovoltaic module's photoelectric conversion efficiency. Therefore, the yellowing of the adhesive film of photovoltaic modules has become a problem that needs to be solved urgently. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a photovoltaic module and a preparation method thereof, which can effectively isolate the end of the welding strip from direct contact with the adhesive film, and avoid the reaction between the welding strip and the components in the adhesive film, resulting in yellowing of the adhesive film in the photovoltaic module.

[0005] To achieve the above object, according to one aspect of an embodiment of the present invention, a photovoltaic assembly is provided, comprising:

[0006] Battery strings, films and separators;

[0007] The battery string comprises a plurality of battery cells and a plurality of welding strips connecting the battery cells in series;

[0008] The isolation portion covers the end of the welding strip so as to isolate the end of the welding strip from the adhesive film.

[0009] Optionally, the isolation portion comprises: isolation films arranged corresponding to the two ends of each of the welding strips; the content of the auxiliary agent in the isolation films is 0.9wt% to 1.1wt%.

[0010] Optionally, the auxiliary agent includes benzophenone;

[0011] and / or,

[0012] The material of the isolation film includes polyolefin elastomer and / or ethylene-vinyl acetate copolymer.

[0013] Optionally, the isolation portion includes an isolation tape; the light transmittance of the isolation tape is greater than or equal to 90%.

[0014] Optionally, the thickness of the isolation tape is 10 μm to 50 μm.

[0015] Optionally, the ends of all the welding strips on the same main surface of the same battery cell cover the same isolation portion, wherein the length direction of the isolation portion is perpendicular to the extension direction of the welding strip;

[0016] or,

[0017] The isolation portion extends along the extension direction of the welding strip, covering one or more welding strips on one main surface of a battery cell;

[0018] or,

[0019] The isolation portion extends along the extension direction of the welding strip, covering one or more welding strips on the same straight line on the main surfaces of the plurality of battery cells facing the same direction;

[0020] or,

[0021] The isolation portion includes an isolation area independently arranged corresponding to each end of each of the welding strips, and each two adjacent isolation areas are arranged at an interval.

[0022] Optionally, in the case where the ends of all the welding strips on the same main surface of the same battery cell cover the same isolation portion, when the isolation portion includes the isolation film, the width of the isolation film is greater than or equal to 10 mm;

[0023] or,

[0024] In view of the case where the above-mentioned isolation portion includes an isolation area independently arranged corresponding to each end of each of the above-mentioned welding strips, when the above-mentioned isolation portion includes the above-mentioned isolation tape, the length of each of the above-mentioned isolation tapes is 1mm to 5mm, wherein the length direction of the above-mentioned isolation tape is perpendicular to the extension direction of the above-mentioned welding strip.

[0025] Optionally, the isolation portion includes an isolation glue point disposed at the end of the welding strip; the light transmittance of the isolation glue point is greater than or equal to 90%.

[0026] Optionally, the height of the isolation glue dots is less than 150 μm;

[0027] and / or,

[0028] The area of ​​the above isolation glue point is less than 1mm 2 ;

[0029] and / or,

[0030] The curing temperature of the above-mentioned isolation glue points is 80°C to 120°C.

[0031] To achieve the above object, according to another aspect of an embodiment of the present invention, a method for preparing a photovoltaic module is provided, which is used to prepare any of the photovoltaic modules described above, comprising:

[0032] Laying welding strips on the surfaces of several battery cells and welding the welding strips to form a battery string; after the battery string is formed, laying an isolation portion at the end of the welded welding strip; or, during the process of forming the battery string, laying welding strips on the surfaces of several battery cells, laying an isolation portion at the end of the welding strip, and welding the welding strip to form a battery string;

[0033] The cell string with the spacer laid out is stacked and laminated with the adhesive film, cover glass, and back glass.

[0034] One embodiment of the above invention has the following advantages or beneficial effects: by providing an isolation portion covering the end of the welding strip between the adhesive film and the battery cell, the direct contact between the end of the welding strip and the adhesive film is effectively isolated, thereby avoiding the reaction between the welding strip and the components in the adhesive film to cause the adhesive film of the photovoltaic module to turn yellow, thereby improving the appearance of the photovoltaic module and solving the problem of reduced photoelectric conversion efficiency of the photovoltaic module due to yellowing of the adhesive film.

[0035] The further effects of the above-mentioned non-conventional optional manner will be described below in conjunction with the specific implementation manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings are used to better understand the present invention and do not constitute an improper limitation of the present invention.

[0037] Figure 1 is a schematic diagram of a yellowing region of a photovoltaic module in the prior art according to an embodiment of the present invention;

[0038] Figure 2 is a schematic longitudinal cross-sectional view of a photovoltaic assembly in the prior art according to an embodiment of the present invention;

[0039] Figure 3 is an exploded schematic diagram of a photovoltaic assembly according to an embodiment of the present invention;

[0040] Figure 4 is a schematic diagram of the structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the first manner;

[0041] Figure 5 is a schematic longitudinal cross-sectional view of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the first manner;

[0042] Figure 6is a schematic diagram of a first structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the second manner;

[0043] Figure 7 is a schematic diagram of a second structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in a second manner;

[0044] Figure 8 is a schematic longitudinal cross-sectional view of a first structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the second manner;

[0045] Fig. 9 is a schematic longitudinal cross-sectional view of a second structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in a second manner;

[0046] Fig.10 is a schematic diagram of a first structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the third manner;

[0047] Fig.11 is a schematic diagram of a second structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in a third manner;

[0048] Fig.12 is a schematic diagram of the structure of a photovoltaic assembly when the isolation portion according to an embodiment of the present invention is arranged in the fourth manner;

[0049] Fig.13 is a schematic diagram of the structure of a photovoltaic module including an isolation part including isolation glue dots according to an embodiment of the present invention;

[0050] Fig.14 is a schematic longitudinal cross-sectional view of a photovoltaic assembly according to an embodiment of the present invention, wherein the isolation portion includes isolation glue dots;

[0051] FIG. 15( a ) is a schematic diagram of an initial state of a semi-finished photovoltaic module B according to an embodiment of the present invention;

[0052] FIG. 15( b ) is a schematic diagram of the state of a semi-finished photovoltaic module B′ after being baked for 192 hours according to an embodiment of the present invention;

[0053] FIG. 15( c ) is a schematic diagram of the state of a semi-finished photovoltaic module C′ after being baked for 192 hours according to an embodiment of the present invention.

[0054] Reference numerals:

[0055] 10-yellowing area; 20-cell string; 21-cell; 22-solder ribbon; 30-adhesive film; 31-upper adhesive film; 32-lower adhesive film; 40-isolating part; 41-isolating adhesive point; 50-photovoltaic glass; 51-cover glass; 52-back glass. DETAILED DESCRIPTION

[0056] like Figure 1 and Figure 2 As shown, when the adhesive film 30 is laid on the cell 21 provided with the soldering ribbon 22, since the newly formed cross section at the end lacks a protective layer, the solder exposed at the end of the soldering ribbon 22 directly contacts the adhesive film 30, which will cause the adhesive film 30 corresponding to the end of the soldering ribbon 22 to turn yellow, resulting in a yellowed area 10. The yellowing of the adhesive film 30 not only affects the appearance of the photovoltaic module, but also affects the photoelectric conversion efficiency of the photovoltaic module.

[0057] The following is a description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for clarity and conciseness, the description of well-known functions and structures is omitted in the following description.

[0058] It should be pointed out that the embodiments of the present invention and the technical features therein may be combined with each other without conflict.

[0059] It should be noted that the upper surface of the cell 21 in the embodiment of the present invention refers to the side of the solar cell facing the sunlight when the solar cell is working, and correspondingly, the lower surface of the cell 21 refers to the side of the solar cell facing away from the sunlight when the solar cell is working.

[0060] Figure 3 FIG. 1 is an exploded schematic diagram of a photovoltaic module according to an embodiment of the present invention. Figure 3 As shown, the photovoltaic module of the embodiment of the present invention mainly includes: a battery string 20, an adhesive film 30 and an isolation part 40. In addition, the photovoltaic module of the embodiment of the present invention may also include a photovoltaic glass 50.

[0061] The adhesive film 30 includes an upper adhesive film 31 and a lower adhesive film 32, which are respectively located on the upper and lower sides of the battery string 20. The photovoltaic glass 50 includes a cover glass 51 and a back glass 52, wherein the cover glass 51 is located on the side of the upper adhesive film 31 away from the battery string 20, and the back glass 52 is located on the side of the lower adhesive film 32 away from the battery string 20.

[0062] It can be understood that when the photovoltaic module is working, the cover glass 51 faces the sunlight and the back glass 52 faces away from the sunlight.

[0063] The battery string 20 includes a plurality of battery cells 21 and a plurality of welding strips 22 connecting the battery cells 21 in series.

[0064] The isolation portion 40 covers the end of the soldering ribbon 22 to isolate the end of the soldering ribbon 22 from the adhesive film 30 , thereby preventing the end of the soldering ribbon 22 from directly contacting the adhesive film 30 and causing the adhesive film 30 to turn yellow.

[0065] It should be noted that, for ease of understanding, Figure 3 Only one battery string 20 is shown for example, and the battery string 20 shown includes two serially connected solar cells 21. In fact, a photovoltaic module may include several battery strings 20, and each battery string 20 may have several solar cells 21. The number of battery strings 20 in the photovoltaic module and the number of cells 21 in each battery string 20 may be determined according to specific circumstances. Similarly, the number of welding strips 22 on the surface of the cell 21 is also determined according to specific circumstances.

[0066] In addition, depending on the type of solar cell, the soldering ribbon 22 may be located on the upper surface and the lower surface of the solar cell 21 , or may be located only on the upper surface or the lower surface of the solar cell 21 .

[0067] In an optional embodiment, the isolation portion 40 includes: isolation films arranged corresponding to the two ends of each of the above-mentioned welding strips 22. The isolation films cover the ends of each welding strip 22 on the battery cell 21, thereby isolating the ends of the welding strips 22 from the adhesive film 30.

[0068] The light transmittance of the isolation film should be greater than or equal to 90% to prevent the isolation film from blocking sunlight during the operation of the photovoltaic module, resulting in a decrease in the photoelectric conversion efficiency of the photovoltaic module. As an example, the light transmittance of the isolation film can be 90%, 92%, 95% or 97%, etc.

[0069] The thickness of the isolation film should be 0.3 mm to 0.5 mm. As an example, the thickness of the isolation film can be 0.3 mm, 0.35 mm, 0.4 mm or 0.5 mm. By controlling the thickness of the isolation film, it is avoided that the protective ability of the adhesive film 30 on the photovoltaic module is reduced due to a large gap between the welding strip 22 and the adhesive film 30.

[0070] The material of the isolation film includes polyolefin elastomer (POE) and / or ethylene vinyl acetate copolymer (EVA), but is not limited thereto.

[0071] The content of the auxiliary agent in the isolation film is 0.9wt% to 1.1wt%. The auxiliary agent may include a plasticizer, an anti-aging agent, a stabilizer, a cross-linking agent, a coupling agent, etc. As an example, the content of the auxiliary agent in the isolation film may be 0.9wt%, 1.0wt%, 1.05wt% or 1.1wt%, etc.

[0072] Furthermore, the auxiliary agent includes benzophenone. Benzophenone can be used as both an anti-aging agent and an ultraviolet absorber, and its content has a certain influence on the yellowing phenomenon of the adhesive film 30. When the benzophenone content in the isolation film is within the range of 0.9wt% to 1.1wt%, the isolation film has a certain anti-ultraviolet effect and does not cause the adhesive film 30 to turn yellow.

[0073] It is understandable that the material of the isolation film and the additives added therein should have the characteristic of not reacting with the substances in the soldering ribbon 22 and the adhesive film 30 .

[0074] By using an isolation film with additives added to cover the end of the welding strip 22, the direct contact between the adhesive film 30 and the end of the welding strip 22 can be effectively isolated, thereby preventing the adhesive film 30 from turning yellow. At the same time, due to the addition of a certain amount of additives, it has excellent heat resistance, pressure resistance, corrosion resistance, UV resistance and other properties, and plays a good protective role in the preparation and operation of photovoltaic modules.

[0075] In an optional embodiment, the isolation portion 40 includes an isolation tape.

[0076] The light transmittance of the above-mentioned isolation tape should be greater than or equal to 90% to prevent the isolation film from blocking sunlight during the operation of the photovoltaic module, thereby reducing the photoelectric conversion efficiency of the photovoltaic module. As an example, the light transmittance of the isolation film can be 90%, 92%, 95% or 97%, etc.

[0077] The thickness of the isolation tape can be 10μm to 50μm. It is understandable that if the thickness of the isolation tape used to isolate the end of the welding tape 22 and the adhesive film 30 is large, a certain gap may be generated between the welding tape 22 and the adhesive film 30, affecting the fit between the adhesive film 30 and the battery cell 21, reducing the protective ability of the adhesive film 30 to the photovoltaic module, thereby affecting the photoelectric conversion efficiency and life of the photovoltaic module. As an example, the thickness of the isolation tape can be 10μm, 20μm, 25μm, 35μm or 50μm, etc.

[0078] By using an isolation tape with a certain thickness to cover the end of the soldering ribbon 22 , the adhesive film 30 can be effectively isolated from direct contact with the end of the soldering ribbon 22 , reducing the interaction between the adhesive film 30 and the soldering ribbon 22 , and preventing the adhesive film 30 from yellowing.

[0079] like Figure 4-Figure 12 As shown, when the isolation portion 40 includes an isolation film or an isolation tape, the isolation portion 40 in the embodiment of the present invention can be arranged in a variety of ways.

[0080] The first setting method is as follows Figure 4 and Figure 5As shown, the ends of all the welding strips 22 on the same main surface of the same battery cell 21 can be covered with the same isolation portion 40. At this time, the isolation portion 40 on each main surface of the battery cell 21 should cover the ends of all the welding strips 22 on the main surface, and completely cover the end of each welding strip 22, so as to effectively isolate the ends of the welding strips 22 from the adhesive film 30, and also ensure that the isolation portion 40 has good sealing performance on the ends of the welding strips 22, so as to prevent moisture, air, etc. from contacting the ends of the welding strips 22.

[0081] The length direction of the isolation portion 40 is perpendicular to the extension direction of the solder strip 22. The length of the isolation portion 40 may be consistent with the width of the battery cell 21, which may be 183 mm to 199 mm, wherein the width direction of the battery cell 21 refers to the direction perpendicular to the extension direction of the solder strip 22. As an example, the length of the isolation portion 40 may be 183 mm, 189 mm, 195 mm, or 199 mm.

[0082] When the isolating portion 40 is an isolation film, the width of the isolation film should be greater than or equal to 10 mm. As an example, the width of the isolation film can be 10 mm, 15 mm, 19 mm, or 25 mm.

[0083] When the isolation portion 40 is an isolation tape, the width of the isolation tape should be 1-5 mm. As an example, the width of the isolation tape can be 1 mm, 1.7 mm, 2.5 mm, 4 mm or 5 mm.

[0084] The second setting method is as follows Figure 6-Figure 9 As shown, the isolation portion 40 extends along the extension direction of the welding strip 22 to cover one or more welding strips 22 on one main surface of a battery cell 21 .

[0085] Specifically, Figure 6 and Figure 8 As shown, the isolation portion 40 may cover a welding strip 22 on one main surface of a battery cell 21, and the number of isolation portions 40 provided on each battery cell 21 may be the same as the number of welding strips 22. Figure 7 and Fig. 9 As shown, the isolation part 40 can cover multiple welding strips 22 on one main surface of a battery cell 21. There should be no bulges or bubbles between the isolation part 40 and the welding point or battery cell 21, further ensuring the sealing of the isolation part 40 to the welding strip 22.

[0086] The length direction of the isolation portion 40 is the extension direction of the soldering ribbon 22, and the width direction of the isolation portion 40 is perpendicular to the extension direction of the soldering ribbon 22. In addition, the length direction of the battery cell 21 is the extension direction of the soldering ribbon 22, and the width direction of the battery cell 21 is perpendicular to the extension direction of the soldering ribbon 22.

[0087] When the separator 40 is a separator, the width of the separator should be greater than or equal to 10 mm and less than or equal to the width of the battery cell 21. As an example, the width of the separator may be 10 mm, 15 mm, 19 mm or 25 mm.

[0088] The length of the isolation film should be sufficient to completely cover the end of the welding strip 22 and be less than the length of the battery cell 21. Furthermore, the length of the isolation tape can be greater than the length of the welding strip 22 and less than the length of the battery cell 21. Here, the length of the welding strip 22 refers to the length of the welding strip 22 located on one main surface of one battery cell 21.

[0089] When the isolation portion 40 is an isolation tape, the width of the isolation tape should be greater than or equal to 1 mm and less than or equal to the width of the battery cell 21. As an example, the width of the isolation tape can be 1 mm, 1.7 mm, 2.5 mm, 4 mm or 5 mm.

[0090] The length of the isolation tape should be sufficient to completely cover the end of the welding tape 22 and be less than the length of the battery cell 21. Furthermore, the length of the isolation tape can be greater than the length of the welding tape 22 and less than the length of the battery cell 21. Here, the length of the welding tape 22 refers to the length of the welding tape 22 located on one main surface of one battery cell 21.

[0091] The third setting method is as follows Fig.10 and Fig.11 As shown, the isolation portion 40 extends along the extension direction of the welding strip 22 to cover one or more welding strips 22 on the same main surface of the plurality of battery cells 21 facing the same direction and located on the same straight line.

[0092] Specifically, when the same welding strip 22 laid on adjacent battery cells 21 in the battery string 20 is located on the same main surface, each welding strip 22 extends toward the same main surface on the adjacent multiple battery cells 21, and one welding strip 22 is located on a straight line, and the straight lines where the adjacent welding strips 22 are located are parallel to each other, such as Fig.10 As shown, the isolation portion 40 may cover a strip 22, or, as shown in FIG. Fig.11 As shown, the isolation part 40 can cover a plurality of welding strips 22. There should be no bulges or bubbles between the isolation part 40 and the welding points and the battery cells 21, so as to further ensure the sealing of the isolation part 40 to the welding strips 22.

[0093] As an example, when the same welding strip 22 laid on adjacent battery cells 21Ⅰ and battery cells 21Ⅱ in the battery string 20 has one end located on the upper surface of the battery cell 21Ⅰ and the other end located on the upper surface of the battery cell 21Ⅱ, the isolation portion 40 can extend from one end of the welding strip 22 to the other end, covering the entire welding strip 22 located on the battery cells 21Ⅰ and the battery cells 21Ⅱ.

[0094] When the separator 40 is a separator, the width of the separator should be greater than or equal to 10 mm and less than or equal to the width of the battery cell 21. As an example, the width of the separator may be 10 mm, 15 mm, 19 mm or 25 mm.

[0095] The length of the isolation film should be sufficient to completely cover the end of the welding strip 22 and be less than the length of the battery cell 21. Furthermore, the length of the isolation tape can be greater than the length of the welding strip 22 and less than the length of the battery cell 21. Here, the length of the welding strip 22 refers to the length of the entire welding strip 22 located in the same straight line on the same main surface of adjacent battery cells 21.

[0096] When the isolation portion 40 is an isolation tape, the width of the isolation tape should be greater than or equal to 1 mm and less than or equal to the width of the battery cell 21. As an example, the width of the isolation tape can be 1 mm, 1.7 mm, 2.5 mm, 4 mm or 5 mm.

[0097] The length of the isolation tape should be sufficient to completely cover the end of the welding tape 22 and be less than the length of the battery cell 21. Furthermore, the length of the isolation tape can be greater than the length of the welding tape 22 and less than the length of the battery cell 21. Here, the length of the welding tape 22 refers to the length of the entire welding tape 22 located in the same straight line on the same main surface of adjacent battery cells 21.

[0098] The length direction of the isolation portion 40 is the extension direction of the soldering strip 22 , and the width direction of the isolation portion 40 is perpendicular to the extension direction of the soldering strip 22 .

[0099] The fourth setting method is as follows Fig.12 As shown, the isolation part 40 includes an isolation area independently arranged corresponding to each end of each of the above-mentioned welding strips 22, and each two adjacent isolation areas are arranged at intervals. Each isolation area covers an end of a welding strip 22, and the number of isolation areas existing on a main surface of the same battery cell 21 is the same as the number of ends of the welding strip 22 on the surface, thereby saving the material cost of the isolation part 40.

[0100] When the isolation area is an isolation film, the width of each isolation film should be greater than or equal to 10 mm and less than or equal to 50 mm. As an example, the width of each isolation film can be 10 mm, 20 mm, 30 mm, 42 mm or 50 mm.

[0101] The length of each isolation film should be 1 mm to 5 mm. As an example, the length of each isolation film can be 1 mm, 2 mm, 3 mm, 4 mm or 5 mm.

[0102] When the isolation area is an isolation tape, the width of each isolation tape should be 1-5 mm. As an example, the width of each isolation tape can be 1 mm, 1.7 mm, 2.5 mm, 4 mm or 5 mm.

[0103] The length of each of the above-mentioned isolation tapes is 1 mm to 5 mm. As an example, the length of each isolation tape can be 1 mm, 1.7 mm, 2.5 mm, 4 mm or 5 mm.

[0104] The length direction of the isolation portion 40 is the extension direction of the soldering strip 22 , and the width direction of the isolation portion 40 is perpendicular to the extension direction of the soldering strip 22 .

[0105] It should be noted that Figure 4-Figure 14 Only part of the structure of the photovoltaic module is shown. Figure 5 , Figure 8 and Fig. 9 Only the partial structure of the photovoltaic module is shown, including the cell 21 and a plurality of welding strips 22 disposed on one main surface of the cell 21, and the isolation portion 40 and the adhesive film 30 covered on the above welding strips 22 on one main surface of the cell 21. When the other main surface of the cell 21 is provided with welding strips 22, the structure of the isolation portion 40 and the adhesive film 30 covered on the other main surface may be the same as or different from the structure shown. As an example, Figure 5 As shown, the isolation portion 40 in one main surface of the battery cell 21 can be arranged in the first manner. When a welding strip 22 is also arranged in the other main surface of the battery cell 21, the isolation portion 40 in the other main surface can be arranged in the first manner, the second manner or the fourth manner.

[0106] It is understandable that, in addition to the above four configurations, the isolation portion 40 may also have other configurations, which are not limited here. Regardless of which configuration is adopted, the isolation portion 40 must at least completely cover the end of the solder strip 22 to prevent the end of the solder strip 22 from directly contacting the adhesive film 30.

[0107] In an optional embodiment, if Fig.13 and Fig.14 As shown, the isolation portion 40 includes an isolation glue dot 41 disposed at the end of the welding strip 22. The light transmittance of the isolation glue dot 41 should be greater than or equal to 90% to prevent the isolation glue dot 41 from blocking sunlight during the operation of the photovoltaic module, resulting in a decrease in the photoelectric conversion efficiency of the photovoltaic module. As an example, the light transmittance of the isolation glue dot 41 can be 90%, 92%, 95% or 97%, etc. The curing temperature of the isolation glue dot 41 should be 80°C to 120°C. As an example, the isolation glue dot 41 can be 80°C, 90°C, 100°C or 120°C, etc.

[0108] The isolation glue dots 41 may be made of an acrylic adhesive, but are not limited thereto. The isolation glue dots 41 should be made of an adhesive that does not react with the solder ribbon 22 , the adhesive film 30 and the battery cell 21 .

[0109] The height H of the isolation glue dot 41 should be less than 150 μm. Fig.14 As shown, the height H of the isolation glue point 41 refers to the height of the glue between the edge of the soldering strip 22 close to the glue film 30 and the glue film 30. The area of ​​the isolation glue point 41 should be less than 1mm 2 As an example, the height of the isolation glue dot 41 may be 100 μm, 120 μm, or 150 μm, etc., and the area of ​​the isolation glue dot 41 may be 0.5 mm 2 , 0.7mm 2 or 1mm 2 When the isolation portion 40 includes the isolation glue dot 41 , the size of the isolation glue dot 41 must at least be sufficient to completely cover the end of the soldering ribbon 22 to prevent the end of the soldering ribbon 22 from directly contacting the adhesive film 30 .

[0110] Furthermore, the insulating glue dots 41 can be applied by printing or dispensing, and the position and amount of the insulating glue dots 41 can be accurately controlled during the printing or dispensing process, so that the insulating glue dots 41 fully wrap the ends of the welding strips 22 without obvious overflow, and the amount of glue is moderate, so as to form a uniform layer of insulating glue dots 41 at the ends of the welding strips 22, and while effectively isolating the ends of the welding strips 22 from direct contact with the adhesive film 30, the insulating glue dots 41 will not cause other effects on the welding strips 22 or the battery cells 21. After the insulating glue dots 41 are completely cured, the subsequent preparation of the photovoltaic module can be continued.

[0111] According to the photovoltaic module of the embodiment of the present invention, an isolation portion 40 covering the end of the welding ribbon 22 is provided between the adhesive film 30 and the battery cell 21, so as to effectively isolate the end of the welding ribbon 22 from direct contact with the adhesive film 30, thereby avoiding the phenomenon that the adhesive film 30 of the photovoltaic module turns yellow due to the reaction between the welding ribbon 22 and the components in the adhesive film 30, thereby improving the appearance of the photovoltaic module and solving the problem that the photoelectric conversion efficiency of the photovoltaic module decreases due to the yellowing of the adhesive film 30.

[0112] The following further describes the content of the auxiliary agent in the isolation film of the present invention being 0.9 wt % to 1.1 wt % in conjunction with the examples.

[0113] In the case where the auxiliary agent is benzophenone, an isolating film a with a benzophenone content of 0.8wt%, an isolating film b with a benzophenone content of 1.0wt%, and an isolating film c with a benzophenone content of 1.3wt% are respectively selected to cover the end of the welding strip 22 in the battery cell 21, and then a glue film 30 is laid on the welding strip 22 covered with the isolating film to obtain a photovoltaic module semi-finished product A, a photovoltaic module semi-finished product B, and a photovoltaic module semi-finished product C. Among them, the photovoltaic module semi-finished product A is provided with an isolating film a for isolating the end of the welding strip 22 from the glue film 30, the photovoltaic module semi-finished product B is provided with an isolating film b for isolating the end of the welding strip 22 from the glue film 30, and the photovoltaic module semi-finished product C is provided with an isolating film c for isolating the end of the welding strip 22 from the glue film 30. The state of the photovoltaic module semi-finished product B is shown in FIG. 15(a), and the states of the photovoltaic module semi-finished product A and the photovoltaic module semi-finished product C are similar to the state of the photovoltaic module semi-finished product B.

[0114] At a temperature of 120°C and other conditions being the same, the photovoltaic module semi-finished product A, the photovoltaic module semi-finished product B and the photovoltaic module semi-finished product C were baked for 192 hours respectively, and the photovoltaic module semi-finished product A', the photovoltaic module semi-finished product B' and the photovoltaic module semi-finished product C' were obtained. Among them, the state of the photovoltaic module semi-finished product B' is shown in Figure 15(b), the state of the photovoltaic module semi-finished product A' is similar to the state of the photovoltaic module semi-finished product B', and neither of them has yellowing phenomenon. The state of the photovoltaic module semi-finished product C' is shown in Figure 15(c), and yellowing phenomenon has occurred. It can be seen that the content of benzophenone in the isolation film has a certain influence on the yellowing of the film 30. The higher the benzophenone content, the more obvious the yellowing phenomenon. Considering that benzophenone has anti-aging and ultraviolet absorption effects, when the benzophenone content in the isolation film is low, the anti-aging and ultraviolet absorption performance is insufficient. Therefore, the embodiment of the present invention sets the content of the auxiliary agent in the isolation film to 0.9wt%~1.1wt%. On the basis of ensuring that the isolation film has sufficient anti-aging performance and ultraviolet absorption performance, the isolation film itself and the adhesive film 30 can be prevented from yellowing, and the contact between the end of the welding strip 22 and the adhesive film 30 can be effectively isolated.

[0115] The embodiment of the present invention further provides a method for preparing a photovoltaic module, which is used to prepare any of the photovoltaic modules described above, and comprises the following steps M1 to M2:

[0116] Step M1, laying welding strips 22 on the surfaces of a plurality of battery cells 21, and welding the welding strips 22 to form a battery string 20, and laying an isolating portion 40 at the end of the welded welding strips 22; or, in the process of forming the battery string 20, laying welding strips 22 on the surfaces of a plurality of battery cells 21, laying an isolating portion 40 at the end of the welding strips 22, and welding the welding strips 22 to form a battery string 20;

[0117] Step M2 , stacking and laminating the battery string 20 with the isolation portion 40 laid thereon, the adhesive film 30 , the cover plate, and the back plate.

[0118] When the material of the isolation part 40 cannot withstand welding conditions, the isolation part 40 can be laid at the end of the welding strip 22 after the battery string 20 is formed, and then the subsequent processes such as laying the adhesive film 30 are continued to form a photovoltaic module with the isolation part 40.

[0119] In the case where the material of the isolation part 40 is resistant to high temperatures and can withstand welding conditions, the isolation part 40 can be laid at the end of the welding tape 22 after laying the welding tape 22 and before welding. After laying the isolation part 40, the welding tape 22 is welded, and subsequent processes such as laying the adhesive film 30 are continued to form a photovoltaic module with an isolation part 40.

[0120] According to the preparation method of the photovoltaic module of the embodiment of the present invention, the isolating portion 40 can be laid at the end of the welding strip 22 before the battery string 20 is formed, or the isolating portion 40 can be laid at the end of the welding strip 22 after the battery string 20 is formed, and then the photovoltaic module with the isolating portion 40 is formed through processes such as laying the adhesive film 30. The isolating portion 40 is laid at the end of the welding strip 22 through simple steps, which can effectively isolate the end of the welding strip 22 from the direct contact with the adhesive film 30, avoid the reaction between the welding strip 22 and the components in the adhesive film 30 to cause the adhesive film 30 to turn yellow in the photovoltaic module, improve the appearance of the photovoltaic module, and at the same time, solve the problem of reduced photoelectric conversion efficiency of the photovoltaic module due to yellowing of the adhesive film 30.

[0121] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions may occur depending on design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photovoltaic module, characterized in that: include: A battery string (20), an adhesive film (30) and an isolation portion (40); The battery string (20) comprises a plurality of battery cells (21) and a plurality of welding strips (22) connecting the battery cells (21) in series; The isolation portion (40) covers the end of the welding strip (22) so that the end of the welding strip (22) is isolated from the adhesive film (30).

2. The photovoltaic module according to claim 1, characterized in that: The isolation part (40) comprises: isolation films arranged corresponding to the two ends of each welding strip 22; The content of the auxiliary agent in the isolation film is 0.9wt% to 1.1wt%.

3. The photovoltaic module according to claim 2, characterized in that: The auxiliary agent includes benzophenone; and / or, The material of the isolation film includes polyolefin elastomer and / or ethylene-vinyl acetate copolymer.

4. The photovoltaic module according to claim 1, characterized in that: The isolation portion (40) comprises an isolation tape; The light transmittance of the isolation tape is greater than or equal to 90%.

5. The photovoltaic module according to claim 4, characterized in that: The thickness of the isolation tape is 10 μm to 50 μm.

6. The photovoltaic module according to claim 2 or 4, characterized in that: The ends of all welding strips (22) on the same main surface of the same battery cell (21) cover the same isolation portion (40), wherein the length direction of the isolation portion (40) is perpendicular to the extension direction of the welding strip (22); or, The isolation portion (40) extends along the extension direction of the welding strip (22) to cover one or more welding strips (22) on a main surface of a battery cell (21); or, The isolation portion (40) extends along the extension direction of the welding strip (22), covering one or more welding strips (22) located on the same straight line on the main surfaces of the plurality of battery cells (21) facing the same direction; or, The isolation portion (40) comprises an isolation area independently arranged corresponding to each end of each welding strip (22), and each two adjacent isolation areas are arranged at an interval.

7. The photovoltaic module according to claim 6, characterized in that: In the case where the ends of all welding strips (22) on the same main surface of the same battery cell (21) cover the same isolation portion (40), when the isolation portion (40) includes the isolation film, the width of the isolation film is greater than or equal to 10 mm; or, In view of the situation where the isolation portion (40) includes an isolation area independently arranged corresponding to each end of each welding strip (22), when the isolation portion (40) includes the isolation tape, the length of each isolation tape is 1 mm to 5 mm, wherein the length direction of the isolation tape is perpendicular to the extension direction of the welding strip (22).

8. The photovoltaic module according to claim 1, characterized in that: The isolation portion (40) comprises an isolation glue point (41) arranged at the end of the welding strip (22); The light transmittance of the isolation glue dots (41) is greater than or equal to 90%.

9. The photovoltaic module according to claim 8, characterized in that: The height of the isolation glue dots (41) is less than 150 μm; and / or, The area of ​​the isolation glue point (41) is less than 1 mm 2 ; and / or, The curing temperature of the isolation glue dots (41) is 80°C to 120°C.

10. A method for preparing a photovoltaic module, characterized in that: Used to prepare the photovoltaic module according to any one of claims 1 to 9, comprising: Laying welding strips (22) on the surfaces of a plurality of battery cells (21), welding the welding strips (22) to form a battery string (20), and laying an isolating portion (40) at the end of the welded welding strips (22); or, during the process of forming the battery string (20), laying welding strips (22) on the surfaces of a plurality of battery cells (21), laying an isolating portion (40) at the end of the welding strips (22), and welding the welding strips (22) to form a battery string (20); The battery string (20) with the spacer (40) laid thereon is stacked and laminated with the adhesive film (30), the cover glass (51) and the back glass (52).

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