Photovoltaic module and conductive backsheet

Abstract

The application provides a photovoltaic module and a conductive backboard, and relates to the technical field of photovoltaic technology. The photovoltaic module comprises a cell string array, an insulating layer, a conductive layer and a backboard which are sequentially stacked; the conductive layer is in a finger-shaped structure distribution, and adjacent finger-shaped structures are isolated by waste silk grooves; the insulating layer is provided with a plurality of conductive through holes penetrating through the insulating layer at least at some positions opposite to the finger-shaped structures; the conductive through holes are filled with conductive bodies; the finger-shaped structures are electrically connected with the current collecting grid lines through the conductive bodies; the insulating layer is provided with a plurality of light reflecting through holes at a first position; the light reflecting through holes are used for exposing at least part of the conductive layer, and the first position comprises at least one inter-sheet gap and / or at least one inter-string gap. The position of the light reflecting through hole is not the position electrically connected with the current collecting grid line, so as to not cause a short circuit risk; the conductive layer at the position of the light reflecting through hole reflects the light entering from the light-receiving side of the photovoltaic module to the back contact cell sheet to be utilized by the back contact cell sheet, so as to improve the light utilization rate.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a photovoltaic module and a conductive backsheet. Background Technology

[0002] Back-contact solar cells, due to their structure without grid lines on the light-facing side, can make full use of sunlight, resulting in higher efficiency.

[0003] However, individual back-contact solar cells have poor mechanical strength, are easily affected by the environment, and have very low output voltage, current, and power. Therefore, multiple back-contact solar cells are usually encapsulated into photovoltaic modules for use.

[0004] However, existing photovoltaic modules have low light utilization rates, which reduces their performance. Utility Model Content

[0005] This application provides a photovoltaic module and a conductive backsheet, which aims to solve the problem of low light utilization in existing photovoltaic modules.

[0006] A first aspect of this application provides a conductive backplate, comprising: an insulating layer, a conductive layer, and a backplate stacked sequentially; The conductive layer is distributed in a finger-like structure, and adjacent finger-like structures are isolated by waste wire grooves; At least a portion of the insulating layer opposite to the finger structure is provided with a plurality of conductive vias penetrating the insulating layer; at least a portion of the insulating layer offset from the conductive vias is provided with a plurality of reflective vias penetrating the insulating layer, the reflective vias being used to expose at least a portion of the conductive layer.

[0007] In the conductive backsheet of this application, at least a portion of the positions where the insulating layer and the finger-like structures of the conductive layer are opposite each other are provided with a plurality of conductive through-holes penetrating the insulating layer. The finger-like structures protrude from these conductive through-holes and are electrically connected to the current collector grid lines of the back contact solar cell. At least a portion of the insulating layer offset from the conductive through-holes is a position where it does not need to be electrically connected to the current collector grid lines of the back contact solar cell. At this position, a plurality of reflective through-holes penetrating the insulating layer are provided. Since the positions of these reflective through-holes are not electrically connected to the current collector grid lines of the back contact solar cell, they will not cause a short circuit risk. The reflective through-holes expose at least a portion of the conductive layer. During the use of this conductive backsheet, at least at the position corresponding to the reflective through-holes on the first surface of the conductive layer near the insulating layer, light that has passed through the front encapsulation film from the light-facing side of the photovoltaic module and has not irradiated the back contact solar cell can be reflected onto the back contact solar cell for utilization, thereby improving the light utilization rate of the photovoltaic module and improving the performance of the photovoltaic module.

[0008] In some possible embodiments, the reflectivity is greater than or equal to 60%.

[0009] In some possible embodiments, the conductive layer is made of a copper-aluminum alloy.

[0010] In some possible embodiments, the reflective aperture does not overlap with the finger structure.

[0011] In some possible embodiments, adjacent reflective apertures are spaced apart.

[0012] A second aspect of this application provides a photovoltaic module, comprising: a battery string array, an insulating layer, a conductive layer, and a backsheet stacked sequentially; the battery string array comprising: a plurality of battery strings arranged in an array; and a plurality of adjacent back-contact cells in the battery strings being electrically connected through the conductive layer. The conductive layer is distributed in a finger-like structure, and adjacent finger-like structures are isolated by waste wire grooves; The back contact battery cell includes: a battery body, and a plurality of current collector grid lines located on the backlight side of the battery body. At least a portion of the insulating layer corresponding to the finger structure is provided with conductive through holes penetrating the insulating layer, and the conductive through holes are filled with a conductor. The finger structure is electrically connected to the current collector grid lines through the conductor. The insulating layer has a plurality of reflective through holes at a first position, the reflective through holes being used to expose at least a portion of the conductive layer; the first position includes: at least one gap between adjacent back contact cells in the battery string, and / or, at least one gap between adjacent battery strings in the battery string array.

[0013] In this application, no back-contact cells or current collector grids are provided at the cell gap and string gap positions. Therefore, the reflective vias at the cell gap and string gap positions will not cause a short circuit risk. Reflective vias are provided in the insulating layer at positions corresponding to the cell gap and string gap to expose at least a portion of the conductive layer. During the operation of this photovoltaic module, the conductive layer near the first surface of the insulating layer, at least at positions corresponding to the reflective vias, can reflect light that has passed through the front encapsulation film from the light-facing side of the photovoltaic module and has not yet reached the back-contact cells back to the back-contact cells for utilization, thereby improving the light utilization rate of the photovoltaic module and enhancing its performance.

[0014] In some possible embodiments, a reflective coating is provided on the first surface of the conductive layer near the insulating layer, at least at the position corresponding to the reflective through-hole.

[0015] In some possible embodiments, for two intersecting and adjacent reflective apertures extending along a first direction and a second direction, the distance between the two closest aperture endpoints located in the two reflective apertures is greater than or equal to 0.5 mm; the first direction is different from the second direction. In some possible embodiments, the shape of the reflective aperture includes at least one of the following: rectangular or T-shaped.

[0016] In some possible embodiments, the width of the first reflective aperture located at the gap between the cells is smaller than the first distance between the rear edge conductive aperture of the preceding back contact cell and the front edge conductive aperture of the following back contact cell in the battery string. And / or, The width of the second reflective through hole located at the gap between the strings is smaller than the second distance between the rear edge conductive through hole of the back contact cell of the rear edge of the preceding battery string and the front edge conductive through hole of the back contact cell of the front edge of the following battery string.

[0017] In some possible embodiments, the back contact cell further includes: a plurality of interconnections disposed on the side of the current collector grid line away from the battery body, wherein the finger structure is electrically connected to the current collector grid line through a conductor and the interconnections; The width of the first reflective aperture located at the gap between the cells is smaller than the third distance between the rear edge interconnection portion of the previous back contact cell and the front edge interconnection portion of the next back contact cell in the battery string. And / or, The width of the second reflective aperture located at the gap between the strings is smaller than the fourth distance between the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front edge interconnection portion of the back contact cell of the front edge of the following battery string.

[0018] In some possible embodiments, the back contact cell further includes: a plurality of interconnections disposed on the side of the current collector grid line away from the battery body, wherein the finger structure is electrically connected to the current collector grid line through a conductor and the interconnections; The width of the first reflective through hole located at the gap between the cells is smaller than the smaller of the first distance and the third distance; the first distance is the distance between the rear edge conductive through hole of the preceding back contact cell and the front edge conductive through hole of the following back contact cell in two adjacent back contact cells in the battery string; the third distance is the distance between the rear edge interconnection portion of the preceding back contact cell and the front edge interconnection portion of the following back contact cell in two adjacent back contact cells in the battery string. And / or, The width of the second reflective aperture located at the gap between the strings is less than the smaller of the second distance and the fourth distance; the second distance is the distance between the rear edge conductive aperture of the back contact cell of the rear edge of the preceding battery string and the front edge conductive aperture of the back contact cell of the front edge of the following battery string in two adjacent battery strings; the fourth distance is the distance between the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front edge interconnection portion of the back contact cell of the front edge of the following battery string in two adjacent battery strings.

[0019] In some possible embodiments, the number of insulating layers is greater than or equal to 1, and at least one insulating layer corresponds to at least two adjacent back contact cells in the battery string, the first position including at least one gap between adjacent back contact cells in the battery string.

[0020] The photovoltaic modules and conductive backsheets mentioned above have the same or similar beneficial effects, and will not be repeated here to avoid repetition. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 A partial structural schematic diagram of a photovoltaic module according to an embodiment of this application is shown; Figure 2 A schematic diagram of the structure of a photovoltaic module according to an embodiment of this application is shown; Figure 3 A schematic diagram of the structure of an insulating layer in an embodiment of this application is shown; Figure 4 This illustration shows a perspective view of the structure of a back contact battery cell, an insulating layer, and a conductive layer combined in an embodiment of this application.

[0023] Explanation of the attached drawing numbers: 1-Conductive backplate, 11-Insulating layer, 111-Conductive through hole, 112-Reflective through hole, 1121-First reflective through hole, 1122-Second reflective through hole, 12-Conductive layer, 121-Waste wire groove, 122-Finger structure, 13-Film layer, 14-Backplate, 2-Back contact cell, 3-Front encapsulation film, 4-Glass, 5-Conductor, 6-Insulating component. Detailed Implementation

[0024] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0025] This application provides a conductive backplate, as shown in the reference. Figure 1 and Figure 2 The conductive backplate 1 includes an insulating layer 11, a conductive layer 12, and a backplate 14 stacked sequentially. The conductive layer 12 is formed of a conductive material, such as an electroplated metal conductive film (gold, silver, copper, aluminum, etc.) or metal foil, etc., without specific limitations. The backplate 14 provides support for the other layers of the conductive backplate 1, and its specific material is not limited; for example, it can be glass. It should be noted that, referring to… Figure 1 and Figure 2 The insulating layer 11 here can be approximately the same size as the conductive layer 12 and the backplate 14, or the insulating layer 11 can be smaller. The insulating layer 11 is approximately the same size as at least two back contact cells 2, with at least two back contact cells 2 corresponding to one insulating layer 11. The backplate 14 corresponds to two or more insulating layers 11, all of which are within the protection scope of this application. The size of the insulating layer with through holes can refer to the size of the insulating layer including the through holes, and the size of the conductive layer with waste wire grooves can refer to the size of the conductive layer including the waste wire grooves.

[0026] Reference Figure 4 The conductive layer is distributed in a finger-like structure 122, and adjacent finger-like structures 122 are isolated by waste wire grooves 121 to avoid short circuits. Except for the waste wire grooves, the conductive layer can be considered to consist entirely of finger-like structures.

[0027] Reference Figures 2 to 4At least a portion of the insulating layer 11 opposite to the finger structure 122 is provided with a plurality of conductive vias 111 penetrating the insulating layer 11; at least a portion of the insulating layer 11 is staggered from the conductive vias 111 and is provided with a plurality of reflective vias 112 penetrating the insulating layer 11, the reflective vias 112 being used to expose at least a portion of the conductive layer. In this application, "staggered" means that the conductive vias 111 and the reflective vias 112 are separate and cannot intersect. In a photovoltaic module, the back contact cell 2 includes: a cell body, and a plurality of collector grid lines located on the backlight side of the cell body, the cell body containing a PN junction. The collector grid lines are used to collect and conduct current or charge carriers. The conductive vias 111 of the insulating layer 11 are filled with a conductor 5. The conductor 5 has good conductivity, and the conductor 5 can be solder paste, solder glue, conductive adhesive, etc. The composition of the conductor 5 can be selected from metal parts such as silver, copper, lead, bismuth, zinc, and nickel; the specific material of the conductor 5 is not limited. The portion of the collector grid line located at the through-hole is electrically connected to the conductive layer 12 via the conductor 5 to conduct current. When the conductive through-hole 111 is small, exposing only a collector grid line of one polarity, the insulating layer 11 can provide insulation, and an insulating component is unnecessary; see reference... Figure 2 When the conductive via 111 is relatively large, exposing two polarities of collector grid lines, one polarity of the collector grid line at the conductive via 111 is electrically connected to the conductive layer 12 through the conductor 5 to conduct current. The other polarity of the collector grid line at the conductive via 111 is insulated by an insulating element 6, which insulates it from the conductive layer 12. This means that the other polarity of the collector grid line at the conductive via 111 is shielded by the insulating element 6, avoiding the risk of short circuits. Other areas of the back-contact cell 2 are in contact with the insulating layer 11 to prevent short circuits and power loss. The two polarities of the collector grid lines here refer to: P-type collector grid lines electrically connected to the P-type doped layer, and N-type collector grid lines electrically connected to the N-type doped layer. The insulating element 6 here has good insulation properties and can be insulating adhesive, etc., with no limitation on its specific composition. The conductor 5 here can directly contact the collector grid lines to achieve electrical connection.

[0028] Reference Figure 3 and Figure 4The conductive layer 12, near the first surface of the insulating layer 11, at least at the position corresponding to the reflective aperture 112, has a strong reflective ability for light incident upon it. The position of the conductive layer 12 near the first surface of the insulating layer 11, at least corresponding to the reflective aperture, can mean that light parallel to the stacking direction of the insulating layer 11, conductive layer 12, and backsheet 14, or the thickness direction of the conductive backsheet, or the thickness direction of the photovoltaic module, irradiates the stacked insulating layer 11 and conductive layer 12. This light passes through the reflective aperture 112 on the insulating layer 11 and irradiates the area of ​​the conductive layer 12 near the first surface of the insulating layer 11. Therefore, in the conductive backsheet of this application, the finger structure 122 protrudes from the conductive through-hole 111 and is electrically connected to the current collector grid lines of the back contact cell. At least a portion of the insulating layer 11 offset from the conductive through-hole 111 is a position where it does not need to be electrically connected to the current collector grid lines of the back contact cell. Several reflective through-holes 112 penetrating the insulating layer are provided at these positions. Since the locations of these reflective through-holes 112 are not electrically connected to the current collector grid lines of the back contact cell, they do not pose a short-circuit risk. During the use of this conductive backsheet, the conductive layer 12, near the first surface of the insulating layer 11, at least at the position corresponding to the reflective through-holes 112, can reflect light that has passed through the front encapsulation film from the light-facing side of the photovoltaic module and has not irradiated the back contact cell back onto the back contact cell for utilization, thereby improving the light utilization rate of the photovoltaic module and enhancing its performance.

[0029] For details, please refer to [reference needed]. Figure 2 The photovoltaic module may further include a front encapsulating film 3 and glass 4 sequentially stacked on the light-facing side of the back-contact cells. The light-facing side of the photovoltaic module can refer to the side of the photovoltaic module closest to the glass 4. The location of the reflective through-hole 112 can be at least one of two locations: the gap between adjacent back-contact cells in the cell string or the gap between adjacent cell strings.

[0030] In one possible embodiment, the reflectivity of the conductive layer 12 near the first surface of the insulating layer 11, at least at the location corresponding to the reflective via 112, is greater than or equal to 60%. The higher the reflectivity at this location, the stronger the ability of light passing through the front encapsulation film from the light-facing side of the photovoltaic module and not illuminating the back contact cell to be reflected onto the back contact cell for utilization, further improving the light utilization rate of the photovoltaic module and its performance. Furthermore, a reflectivity of greater than or equal to 80% at this location represents an even higher reflectivity, further enhancing the light utilization rate of the photovoltaic module.

[0031] For example, the reflectivity of the first surface of the conductive layer 12 near the insulating layer 11, at least at the position corresponding to the reflective through hole 112, can be 60%, 63%, 65%, 70%, 75%, 80%, 83%, 85%, 88%, 90%, 94%, or 95%.

[0032] It should be noted that the reflectivity of the first surface of the conductive layer 12 near the insulating layer 11, at least at the position corresponding to the reflective through-hole 112, refers to the ratio of the light flux reflected at that position to the light flux incident on that position, expressed as a percentage. The reflectivity of this position of the conductive layer 12 in the conductive backsheet can be directly measured using a spectrophotometer, reflectivity tester, etc. A region of a predetermined area can be arbitrarily selected at this position, and the reflectivity of that region can be measured as the reflectivity of that position. Alternatively, the reflectivity of two, three, four, etc., predetermined areas can be measured, and the arithmetic mean can be taken as the reflectivity of that position. The size of the predetermined area is not limited. In photovoltaic modules, since glass and a pre-encapsulating film are also provided on the light-facing side at this position, the glass and pre-encapsulating film can be removed to expose the position, and then the reflectivity of that position can be measured using a method similar to the aforementioned method. Alternatively, the glass and pre-encapsulating film can be left in place, and the reflectivity of that position can be measured directly using a method similar to the aforementioned method. In this application, the methods for measuring the reflectivity of this position include, but are not limited to, the methods exemplified above.

[0033] In one possible embodiment, the conductive layer is made of a copper-aluminum alloy, which is an alloy material with copper (Cu) and aluminum (Al) as its main components. This alloy combines the conductivity and corrosion resistance of copper with the lightweight properties of aluminum, exhibiting not only good conductivity but also high surface reflectivity, good mechanical properties, and ease of processing into the aforementioned finger-like structure. Furthermore, the copper-aluminum alloy has good thermal conductivity, which can reduce the probability of hot spots in the photovoltaic module. In this case, the first surface of the conductive layer 12 near the insulating layer 11, at least at the position corresponding to the reflective through-hole 112, has a high reflectivity, eliminating the need for an additional reflective coating process. This simplifies the process, improves production efficiency, and reduces equipment costs by eliminating the need for additional equipment for applying reflective coatings. For example, the reflectivity of the surface of the conductive layer containing the copper-aluminum alloy is greater than or equal to 60%, or even greater than or equal to 80%. It should be noted that the mass ratio of copper and aluminum in the conductive layer is not specifically limited.

[0034] In one possible embodiment, the conductive layer can be produced by electroplating, PVD (Physical Vapor Deposition), calendering, etc., forming a dense metal film with a surface reflectivity greater than or equal to 80%. Specific limitations are not imposed on its density, surface roughness, reflectivity, etc. For example, the aforementioned conductive layer containing copper-aluminum alloy can be prepared using the aforementioned related preparation methods.

[0035] In one possible embodiment, the conductive layer 12, near the first surface of the insulating layer 11, has a reflective coating at least at the position corresponding to the reflective through-hole 112. In this case, the reflectivity of the positions in the conductive layer 12 not corresponding to the reflective through-hole 112 does not need to be considered; only conductivity needs to be considered, which can appropriately reduce the cost of the conductive layer. This reflective coating has a high reflectivity; for example, the reflectivity of the surface of the reflective coating is greater than or equal to 60%, or even greater than or equal to 80%.

[0036] The reflective coating here can be reflective tape, highly reflective metallic film, such as copper or aluminum alloy. There are no specific limitations on the material of the reflective coating.

[0037] In one possible embodiment, refer to Figure 4 The reflective via 112 and the finger structure 122 do not overlap. This non-overlap means that when light parallel to the stacking direction of the insulating layer 11, conductive layer 12, and backplate 14 is shone onto the stacked insulating layer 11 and conductive layer 12, the projection of the reflective via 112 onto the first surface of the conductive layer 12 is separate from the finger structure 122. Typically, the size of the conductive via 111 is smaller than the size of the finger structure 122. To ensure good current collection, the current collector grid lines of the back contact cell are usually located within the conductive via 111. Therefore, only the portion of the finger structure 122 located within the conductive via 111 that is aligned with the current collector grid lines of the back contact cell can be electrically connected. The portion of the finger structure 122 located outside the conductive via 111 is not aligned with the current collector grid lines of the back contact cell and cannot be electrically connected. Therefore, the reflective via 112 and the finger structure 122 do not overlap, further reducing the risk of short circuits caused by the reflective via 112.

[0038] In one possible embodiment, refer to Figure 4 The adjacent reflective through holes 112 are spaced apart, and the size of the reflective through holes 112 is not too large and they are not connected into one piece. On the one hand, this can reduce the risk of short circuit, and on the other hand, it avoids the problem of cracking or damage caused by excessive reduction in mechanical properties due to large-area openings in the insulation layer 11.

[0039] It should be noted that in this application, at least some positions of the insulating layer staggered from the conductive through-holes 111 are provided with a number of reflective through-holes 112 penetrating the insulating layer 11. This indicates that the conductive through-holes 111 and the reflective through-holes 112 are also spaced apart and will not be connected into one piece. On the one hand, this can reduce the risk of short circuits, and on the other hand, it avoids the problem of cracking or damage caused by excessive degradation of mechanical properties due to large-area openings in the insulating layer 11.

[0040] In one possible embodiment, refer to Figure 4For two adjacent reflective via holes 112 extending along a first direction L1 and a second direction L2 respectively and intersecting with each other, the distance C1 between the two closest via hole endpoints respectively located in the two reflective via holes 112 is greater than or equal to 0.5 mm. Two adjacent reflective via holes extending along a first direction L1 and a second direction L2 and intersecting with each other refer to: two reflective via holes that are spaced apart in both the first direction L1 and the second direction L2, intersect after extension, and are adjacent to each other in both the first direction L1 and the second direction L2, that is, the two reflective via holes are located at the intersection of the first direction L1 and the second direction L2. Specifically, the portion of the insulating layer 11 located at the intersection of the first direction L1 and the second direction L2 is more prone to cracking or damage. When the distance C1 between the two closest via hole endpoints respectively located in the two reflective via holes at this position is relatively large, the problem of cracking or damage caused by excessive decrease in mechanical properties due to insufficient size of the remaining film layer of the insulating layer 11 at this position is reduced. The first direction L1 and the second direction L2 mentioned herein are different, intersect with each other, and the included angle therebetween is not limited. For example, the included angle may be about 90°. The via hole endpoint mentioned in the present application refers to the end or endpoint of a reflective via hole.

[0041] For example, for two adjacent reflective via holes extending along the first direction L1 and the second direction L2 respectively and intersecting with each other, the distance C1 between the two closest via hole endpoints respectively located in the two reflective via holes can be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.5 mm, 1.8 mm, 2 mm, 2.2 mm or 2.5 mm.

[0042] In a possible embodiment, the shape of the reflective via hole 112 comprises at least one of a rectangle and a Chinese character '丰' shape. The shape of the reflective via hole 112 herein refers to the shape of the projection of the reflective via hole 112 on the first surface of the conductive layer 12 when the stacked insulating layer 11 and conductive layer 12 are irradiated with light parallel to the stacking direction of the insulating layer 11, the conductive layer 12 and the back plate 14. The shape of the reflective via hole is relatively regular and is relatively similar to the shape of the conductive via hole, so the reflective via hole can be processed and formed in the same process as the conductive via hole, which has simple process and high production efficiency. For example, Figure 4 in this case, the shape of the reflective via hole 112 is rectangular.

[0043] The present application also provides a photovoltaic module, with reference to Figure 2The photovoltaic module includes: a cell string array, an insulating layer 11, a conductive layer 12, and a backsheet 14 stacked sequentially. Whether the insulating layer 11, conductive layer 12, and backsheet 14 form a conductive backsheet is not limited. The cell string array includes several cell strings arranged in an array; the number of cell strings in the photovoltaic module is not limited. Several adjacent back-contact cells in the cell strings are electrically connected through the conductive layer 12; specifically, the current collector grid lines of several adjacent back-contact cells in the cell strings are electrically connected through the conductive layer 12. The number of back-contact cells in the cell strings is not limited. An insulating layer 11 is located between the back contact cell 2 and the conductive layer 12; the conductive layer 12 is distributed in the form of finger-like structures 122, and adjacent finger-like structures 122 are isolated by waste wire grooves 121; the back contact cell 2 includes: a battery body, and a plurality of current collector grid lines located on the back side of the battery body; at least a portion of the positions corresponding to the insulating layer 11 and the finger-like structures 122 are provided with conductive through holes 111 penetrating the insulating layer 11, and the conductive through holes 111 are filled with conductors 5; the finger-like structures 122 are electrically connected to the current collector grid lines through the conductors 5 to form a battery string.

[0044] A plurality of reflective vias are provided at a first position of the insulating layer 11, which can expose at least a portion of the conductive layer. These first positions include: at least one gap between adjacent back-contact cells 2 within a cell string, and / or at least one gap between adjacent cell strings in a cell string array. No back-contact cells or current collector grids are located at the gaps between cells or the gaps between strings; therefore, the reflective vias 112 at these locations do not pose a short-circuit risk. During the operation of the photovoltaic module, the conductive layer 12, near the first surface of the insulating layer 11, at least at the position corresponding to the reflective via 112, can reflect light that has passed through the front encapsulation film from the light-facing side of the photovoltaic module and has not yet struck the back-contact cells back onto the back-contact cells for utilization, thereby improving the light utilization rate of the photovoltaic module and enhancing its performance.

[0045] It should be noted that the first position here may be approximately the same as at least part of the position of the conductive through-hole offset from the insulating layer in the aforementioned conductive backsheet, or the two may be slightly different, as long as the position corresponding to the reflective through-hole 112 does not cause a short circuit risk, both are within the protection scope of this application. Regarding the reflective through-hole, reflective coating, back contact cell, insulating layer, conductive layer, backsheet, and the shape of the reflective through-hole, the distance between the two closest through-hole endpoints located in the two reflective through-holes, etc., in this photovoltaic module, please refer to the aforementioned relevant descriptions, and will not be repeated here to avoid repetition.

[0046] In some embodiments, reflective vias 112 may be provided only at positions corresponding to the inter-cell gaps in the insulating layer 11. Specifically, the size of the inter-cell gap may typically be larger than the size of the inter-cell gap. Therefore, providing reflective vias only at positions corresponding to the inter-cell gaps already significantly improves light utilization and saves the process of providing reflective vias at positions corresponding to the inter-cell gaps, achieving a balanced optimization of light utilization and process efficiency. It should be noted that in this case, at least a portion of the positions of the conductive vias offset from the insulating layer in the aforementioned conductive backsheet may correspond to the inter-cell gap positions here. In a photovoltaic module, the number of inter-cell gaps is relatively large, and reflective vias may be provided at positions corresponding to 1 inter-cell gap, 2 inter-cell gaps, 3 inter-cell gaps, etc., all of which are within the scope of protection of this application.

[0047] In some embodiments, reflective vias 112 may be provided at positions corresponding to both the inter-cell gaps and inter-string gaps in the insulating layer 11 to further improve light utilization. It should be noted that in this case, at least a portion of the positions of the conductive vias offset from the insulating layer in the aforementioned conductive backsheet may correspond to the inter-cell gap and inter-string gap positions. In a photovoltaic module, the number of inter-string gaps is relatively large; reflective vias may be provided at positions corresponding to 1, 2, 3, etc., all within the scope of protection of this application. For example, Figure 4 In the middle, the insulating layer 11 is provided with a first reflective through hole 1121 at the position corresponding to each gap between the sheets, and a second reflective through hole 1122 is provided at the position corresponding to each gap between the strings.

[0048] In some embodiments, refer to Figure 4 In the direction of extension of the battery string (which can be) Figure 4 (In the direction shown by L1): The width W1 of the first reflective through-hole 1121 located at the gap between the cells is smaller than the first distance C2 between the rear edge conductive through-hole of the preceding back contact cell and the front edge conductive through-hole of the following back contact cell in the battery string. Specifically, the current collector grid of the back contact cell is usually located at the position corresponding to the conductive through-hole 111, and there is usually no current collector grid of the back contact cell outside the position of the conductive through-hole 111. Therefore, W1 < C2, which can largely avoid short circuits. The first distance here is the distance between the rear end of the rear edge conductive through-hole of the preceding back contact cell and the front end of the front edge conductive through-hole of the following back contact cell in the battery string.

[0049] It should be noted that in a battery string, if the first distance between the rear edge conductive via of the preceding back contact cell and the front edge conductive via of the following back contact cell at different positions is not equal, then C2 can be the minimum first distance in the photovoltaic module, any first distance, or the average of two or more first distances. The difference between C2 and W1 is not limited. Whether W1 is greater than the cell gap in the extending direction of the battery string is not limited. For example, in the extending direction of the battery string, W1 can be greater than or equal to the cell gap to fully utilize the space of the cell gap and maximize reflectivity. Alternatively, in the extending direction of the battery string, W1 can be less than the cell gap.

[0050] It should be noted that, specifically, the conductive via at the rear edge of the preceding back contact cell in two adjacent back contact cells in the battery string mentioned in this application can refer to: within the insulating layer, the conductive via corresponding to the edge position of one back contact cell near the other back contact cell, near the end of the other back contact cell; similarly, the conductive via at the front edge of the following back contact cell in two adjacent back contact cells in the battery string mentioned in this application can refer to: within the insulating layer, the conductive via corresponding to the edge position of another back contact cell near the first back contact cell, near the end of the first back contact cell. The preceding and following positions mentioned elsewhere in this application are similar and will not be repeated here to avoid repetition.

[0051] In one possible embodiment, refer to Figure 4 In the direction perpendicular to the extension direction of the battery string (which could be...) Figure 4 (In the direction shown by L2): The width W2 of the second reflective through-hole 1122 located at the string gap position is smaller than the second distance C3 between the rear edge conductive through-hole of the back contact cell at the rear edge of the preceding battery string and the front edge conductive through-hole of the back contact cell at the front edge of the following battery string. Specifically, in two adjacent battery strings, there is no current collector grid line of the back contact cell between the rear edge conductive through-hole of the back contact cell at the rear edge of the preceding battery string and the front edge conductive through-hole of the back contact cell at the front edge of the following battery string, so W2 < C3, which can largely avoid short circuits. The second distance here is the distance between the rear end of the rear edge conductive through-hole of the back contact cell at the rear edge of the preceding battery string and the front end of the front edge conductive through-hole of the back contact cell at the front edge of the following battery string in a direction perpendicular to the extension direction of the battery string.

[0052] It should be noted that in photovoltaic modules, when the second distance between the rear edge conductive via of the back contact cell of the preceding cell string and the front edge conductive via of the back contact cell of the following cell string are not equal in two adjacent cell strings at different locations, C3 can be the minimum corresponding second distance in the photovoltaic module, any second distance, or the average of two or more second distances. The magnitude of the difference between C3 and W2 is not limited. Whether W2 is greater than the string gap in the direction perpendicular to the extension direction of the cell string is not limited. For example, in the direction perpendicular to the extension direction of the cell string, W2 can be greater than or equal to the string gap to fully utilize the space of the string gap and maximize reflectivity. Alternatively, in the direction perpendicular to the extension direction of the cell string, W2 can be less than the string gap.

[0053] In some embodiments, the back contact cell further includes: a plurality of interconnections disposed on the side of the current collector grid line away from the battery body; the finger structure 122 is electrically connected to the current collector grid line via a conductor 5 and the interconnections; the conductor 5 may be disposed on the surface of the interconnection 23 away from the battery body. The interconnection may be a separate component or a thickened section of the current collector grid line. When the interconnection is a thickened section of the current collector grid line, the thickened section of the current collector grid line is thicker than the rest of the current collector grid line. The interconnection may be an electrode disk, etc.

[0054] In some embodiments, in the direction of extension of the battery string (which may be...) Figure 4 (In the direction shown by L1): The width W1 of the first reflective through-hole 1121 located at the gap between the cells is smaller than the third distance between the rear edge interconnection portion of the preceding back contact cell and the front edge interconnection portion of the following back contact cell in the battery string. Specifically, there is essentially no conductive layer electrical connection between the rear edge interconnection portion of the preceding back contact cell and the front edge interconnection portion of the following back contact cell in the battery string. Therefore, W1 < the third distance, which can largely avoid short circuits. The third distance here can be the distance between the rear end of the rear edge interconnection portion of the preceding back contact cell and the front end of the front edge interconnection portion of the following back contact cell in the battery string.

[0055] It should be noted that, in a battery string, if the third distance between the rear edge interconnection portion of the preceding back contact cell and the front edge interconnection portion of the following back contact cell are not equal at different positions, this third distance can be the minimum third distance in the photovoltaic module, any third distance, or the average of two or more third distances. The magnitude of the difference between the third distance and W1 is not limited.

[0056] In one possible embodiment, in a direction perpendicular to the extension direction of the battery string (which could be...) Figure 4 (In the direction shown by L2): The width W2 of the second reflective through-hole 1122 located at the string gap position is smaller than the fourth distance between the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front edge interconnection portion of the back contact cell of the front edge of the following battery string. Similarly, since W2 < the fourth distance, short circuits can be largely avoided. This fourth distance can be the distance between the rear end of the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front end of the front edge interconnection portion of the back contact cell of the front edge of the following battery string, in a direction perpendicular to the extension direction of the battery string.

[0057] It should be noted that when the fourth distance at different locations within a photovoltaic module is not equal, this fourth distance can be the smallest corresponding fourth distance within the photovoltaic module, any fourth distance, or the average of two or more fourth distances. The magnitude of the difference between the fourth distance and W2 is not limited.

[0058] In one possible embodiment, the aforementioned W1 is smaller than the smaller of the aforementioned first distance C1 and the aforementioned third distance, and the width W1 of the first reflective aperture 1121 is smaller, which can further avoid short circuits.

[0059] In one possible embodiment, the aforementioned W2 is smaller than the smaller of the aforementioned second distance C2 and the aforementioned fourth distance, and the width W2 of the second reflective aperture 1122 is smaller, which can further avoid short circuits.

[0060] In one possible embodiment, as mentioned in the aforementioned conductive backsheet, for two adjacent reflective vias extending along the first direction L1 and the second direction L2, the distance C1 between the two closest via endpoints is greater than or equal to 0.5 mm. This corresponds to, in a photovoltaic module, for a first reflective via 1121 and a second reflective via 1122 extending along the first direction L1 and the second direction L2, the distance C1 between the two closest via endpoints is greater than or equal to 0.5 mm. This also reduces the problem of cracking or damage caused by excessive mechanical performance degradation due to insufficient remaining film size of the insulating layer 11 at this location. The relevant content here can be referred to in the aforementioned descriptions, and will not be repeated here to avoid repetition.

[0061] In one possible embodiment, the number of insulating layers in the photovoltaic module is greater than or equal to one, and at least one insulating layer corresponds to the position of at least two adjacent back contact cells in the cell string. The first position includes at least one gap between adjacent back contact cells in the cell string. The insulating layer here can be pre-combined with at least two back contact cells, so the conductive backsheet may not have an insulating layer. In this case, the insulating layer in the photovoltaic module can cover at least one gap. The aforementioned first position includes at least one gap between adjacent back contact cells in the cell string. Typically, the size corresponding to the gap may be larger than the size of the string gap, thus ensuring that a reflective aperture is provided at the position corresponding to the gap, improving light utilization. It should be noted that when the insulating layer is pre-combined with at least two back contact cells, the number of insulating layers in the photovoltaic module can be greater than or equal to two. Alternatively, the insulating layer here is the same as the insulating layer in the aforementioned conductive backsheet.

[0062] In some embodiments, the insulating layer, conductive layer and backsheet in the aforementioned photovoltaic module form any of the aforementioned conductive backsheets. The relevant features in the aforementioned conductive backsheets are also applicable in the photovoltaic module, and will not be repeated here to avoid repetition.

[0063] It should be noted that, unless there is any contradiction, the contents of any of the aforementioned conductive backsheets and the relevant contents of photovoltaic modules can be referenced to each other and have the same or similar beneficial effects. To avoid repetition, they will not be repeated.

[0064] It should be noted that the various embodiments in this application can be used individually or in any combination under different contradictory circumstances. Whether used individually or in any combination, they are all within the protection scope of this application.

[0065] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0066] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A photovoltaic module, characterized in that, include: A battery string array, an insulating layer, a conductive layer, and a backplate are stacked in sequence. The battery string array includes: a plurality of battery strings arranged in an array; a plurality of adjacent back-contact battery cells in the battery strings are electrically connected through the conductive layer. The conductive layer is distributed in a finger-like structure, and adjacent finger-like structures are isolated by waste wire grooves; The back contact battery cell includes: a battery body, and a plurality of current collector grid lines located on the backlight side of the battery body. At least a portion of the insulating layer corresponding to the finger structure is provided with conductive through holes penetrating the insulating layer, and the conductive through holes are filled with a conductor. The finger structure is electrically connected to the current collector grid lines through the conductor. The insulating layer has a plurality of reflective through holes at a first position, the reflective through holes being used to expose at least a portion of the conductive layer; the first position includes: at least one gap between adjacent back contact cells in the battery string, and / or, at least one gap between adjacent battery strings in the battery string array.

2. The photovoltaic module according to claim 1, characterized in that, The conductive layer near the first surface of the insulating layer has a reflective coating at least at the position corresponding to the reflective through hole.

3. The photovoltaic module according to claim 1, characterized in that, For two reflective through holes that intersect and are adjacent along the first and second directions, the distance between the two closest endpoints of the two reflective through holes is greater than or equal to 0.5 mm; the first direction is different from the second direction.

4. The photovoltaic module according to claim 1, characterized in that, The shape of the reflective aperture includes at least one of the following: rectangular and T-shaped.

5. The photovoltaic module according to claim 1, characterized in that, The width of the first reflective through hole located at the gap between the cells is smaller than the first distance between the rear edge conductive through hole of the previous back contact cell and the front edge conductive through hole of the next back contact cell in the battery string. And / or, The width of the second reflective through hole located at the gap between the strings is smaller than the second distance between the rear edge conductive through hole of the back contact cell of the rear edge of the preceding battery string and the front edge conductive through hole of the back contact cell of the front edge of the following battery string.

6. The photovoltaic module according to claim 1, characterized in that, The back contact battery cell further includes: a plurality of interconnecting portions disposed on the side of the current collector grid line away from the battery body, and the finger structure is electrically connected to the current collector grid line through a conductor and the interconnecting portions; The width of the first reflective aperture located at the gap between the cells is smaller than the third distance between the rear edge interconnection portion of the previous back contact cell and the front edge interconnection portion of the next back contact cell in the battery string. And / or, The width of the second reflective aperture located at the gap between the strings is smaller than the fourth distance between the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front edge interconnection portion of the back contact cell of the front edge of the following battery string.

7. The photovoltaic module according to claim 1, characterized in that, The back contact battery cell further includes: a plurality of interconnecting portions disposed on the side of the current collector grid line away from the battery body, and the finger structure is electrically connected to the current collector grid line through a conductor and the interconnecting portions; The width of the first reflective through hole located at the gap between the cells is smaller than the smaller of the first distance and the third distance; the first distance is the distance between the rear edge conductive through hole of the preceding back contact cell and the front edge conductive through hole of the following back contact cell in two adjacent back contact cells in the battery string; the third distance is the distance between the rear edge interconnection portion of the preceding back contact cell and the front edge interconnection portion of the following back contact cell in two adjacent back contact cells in the battery string. And / or, The width of the second reflective aperture located at the gap between the strings is less than the smaller of the second distance and the fourth distance; the second distance is the distance between the rear edge conductive aperture of the back contact cell of the rear edge of the preceding battery string and the front edge conductive aperture of the back contact cell of the front edge of the following battery string in two adjacent battery strings; the fourth distance is the distance between the rear edge interconnection portion of the back contact cell of the rear edge of the preceding battery string and the front edge interconnection portion of the back contact cell of the front edge of the following battery string in two adjacent battery strings.

8. The photovoltaic module according to any one of claims 1 to 7, characterized in that, The number of insulating layers is greater than or equal to 1, and at least one insulating layer corresponds to the position of at least two adjacent back contact cells in the battery string. The first position includes at least one gap between adjacent back contact cells in the battery string.

9. A conductive backplate, characterized in that, include: The insulating layer, conductive layer, and backing plate are stacked in sequence. The conductive layer is distributed in a finger-like structure, and adjacent finger-like structures are isolated by waste wire grooves; The insulating layer has at least a plurality of conductive vias penetrating the insulating layer at a portion of the position opposite to the finger structure. The insulating layer is provided with a plurality of reflective through holes at at least a portion of the position offset from the conductive through hole, the reflective through holes being used to expose at least a portion of the conductive layer.

10. The conductive backplate according to claim 9, characterized in that, The reflective aperture does not overlap with the finger-like structure.

11. The conductive backplate according to claim 9 or 10, characterized in that, Adjacent reflective apertures are spaced apart.

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