Conductive backsheet, manufacturing method for conductive backsheet, and photovoltaic module

Abstract

The present application relates to the technical field of photovoltaics, and discloses a conductive backsheet, a manufacturing method for a conductive backsheet, and a photovoltaic module, which are used to achieve the purposes of high conversion efficiency, low unit manufacturing costs, high unit production efficiency, and high module reliability corresponding to synergistic photovoltaic cells. The conductive backsheet comprises a carrier plate and a patterned conductive layer. The conductive layer is a metal layer disposed on the carrier plate, and a functional surface of the conductive layer used to be in electrical contact with a solar cell has a roughness Ra of 0.02 μm to 0.3 μm.

Description

A conductive backsheet, a method for manufacturing the conductive backsheet, and a photovoltaic module.

[0001] This application claims priority to Chinese Patent Application No. 202411703954.9, filed on November 26, 2024, entitled "A Conductive Backsheet, a Method for Manufacturing a Conductive Backsheet and a Photovoltaic Module", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of photovoltaic technology, and in particular to a conductive backsheet, a method for manufacturing the conductive backsheet, and a photovoltaic module. Background Technology

[0003] Currently, photovoltaic (PV) module manufacturing typically employs either solder strip connection technology or conductive backsheet connection technology. PV modules manufactured using conductive backsheet technology offer advantages such as aesthetic appeal, high power output, and high conversion efficiency.

[0004] Photovoltaic modules using conductive backsheet technology exhibit significant power degradation after prolonged reliability testing in high-heat and high-humidity environments, with power loss approaching 5%, severely impacting their outdoor performance. Therefore, developing a photovoltaic product or component that combines high conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability with compatible photovoltaic cells is crucial in the photovoltaic product manufacturing field.

[0005] Application content

[0006] The purpose of this application is to provide a conductive backsheet, a method for manufacturing the conductive backsheet, and a photovoltaic module, so as to achieve the goals of high conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability in conjunction with photovoltaic cells.

[0007] In a first aspect, this application provides a conductive backplane, including a carrier plate and a patterned conductive layer;

[0008] The conductive layer can be a metal layer disposed on the carrier plate, and the surface roughness Ra of the functional surface of the conductive layer for electrical contact with the battery cell is 0.02μm to 0.3μm.

[0009] With the above technical solution, the roughness of the functional surface of the conductive layer that contacts the solar cell differs from conventional requirements. The roughness Ra is reduced to 0.02μm–0.3μm to improve the reflectivity of the conductive backsheet, resulting in better light absorption by the solar cell under illumination and improved photoelectric conversion efficiency. Furthermore, since the photovoltaic module manufacturing process requires conductive adhesive to connect the conductive layer and the solar cell, the design of the surface roughness of the conductive layer is related to the efficient introduction and function of the conductive adhesive in subsequent processes. The surface roughness of the conductive layer designed in this application promotes the flow of the conductive adhesive in its molten state and increases the bonding area between the two sides of the molten conductive adhesive (the conductive layer and the solar cell, respectively), improving the efficiency and reliability of the conductive adhesive process. It also reduces the stress between the conductive adhesive and the solar cell and conductive layer, preventing microcracks in the solar cell due to excessive stress.

[0010] In some alternative implementations, the conductive layer may include a first metal layer and a second metal layer stacked together, with the first metal layer disposed on a carrier plate and the second metal layer disposed on the first metal layer; the surface roughness Ra1 of the functional surface of the first metal layer is 0.3 μm to 0.5 μm; and the surface roughness Ra2 of the functional surface of the second metal layer is 0.02 μm to 0.3 μm.

[0011] In the above technical solution, the conductive backsheet uses a first metal layer and a second metal layer stacked together. The functional surface of the first metal layer that contacts the carrier has a higher roughness Ra1, which is 0.3μm to 0.5μm. The high roughness of the functional surface of the first metal layer can have a greater bonding strength with the carrier, thereby improving the reliability of the photovoltaic module. The roughness Ra2 of the functional surface of the second metal layer that contacts the solar cell is different from the conventional requirement. The roughness is reduced to 0.02μm to 0.3μm to improve the reflectivity of the conductive backsheet. Under illumination, this allows the solar cell to have a better light absorption effect and improve the photoelectric conversion efficiency. Furthermore, given the photovoltaic module manufacturing process requiring the use of conductive adhesive to connect the conductive layer and the solar cell, the design of the surface roughness of the second metal layer is crucial for the efficient introduction and effective function of the conductive adhesive in subsequent processes. The surface roughness of the second metal layer designed in this application promotes the flow of the conductive adhesive in its molten state and increases the bonding area between the two sides of the molten conductive adhesive (the second metal layer and the solar cell, respectively), improving the efficiency and reliability of the conductive adhesive process. It also reduces the stress between the conductive adhesive and the solar cell and the second metal layer, preventing microcracks in the solar cell due to excessive stress. In addition, since the conductive layer uses at least the first and second metal layers, the range of conductive layer materials is expanded, allowing for rational selection based on conductivity and material cost, resulting in a conductive layer with good conductivity while reducing cost. The conductive backsheet of this application, as a holistic design, achieves synergistic effects of high photovoltaic cell conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability. In some alternative implementations, based on the convenience, efficiency, and effectiveness of the subsequent stripping of invalid regions (waste regions) of the conductive layer, this application also roughens specific edge regions of each effective region (or effective unit, effective region unit, or similar functional name) of the functional surface of the conductive layer. Furthermore, based on the electrical isolation requirements between adjacent effective region units of the conductive backsheet, this application roughens the side surface (or side surface, i.e., the third region, hereinafter the same) of each effective region of the conductive layer to improve or ensure the electrical isolation performance between two adjacent effective regions, further enhancing the reliability of the conductive backsheet product and the reliability of the module using the conductive backsheet. In some implementations of this application, based on the high safety requirements of photovoltaic module products, this application also discloses methods to process the edge regions and side surface regions of the effective regions of the conductive layer to improve the volume resistivity of these regions, and to further effectively improve the electrical isolation performance of adjacent effective regions of the conductive layer by processing these surface regions with an inwardly concave corrugated structure, thereby improving the electrical safety requirements of the conductive backsheet product and enhancing the safety of photovoltaic modules using the conductive backsheet.

[0012] Secondly, this application also provides a method for manufacturing a conductive backplane, comprising:

[0013] Provide a carrier board;

[0014] Provides a patterned conductive layer;

[0015] The carrier plate and the conductive layer are combined, and the surface roughness Ra of the functional surface of the conductive layer for electrical contact with the battery cell is 0.02 μm to 0.3 μm.

[0016] The method for manufacturing the conductive backplate can produce the conductive backplate of the first aspect, and therefore has the same beneficial effects as the first aspect, which will not be described in detail here.

[0017] In some possible implementations, the patterned conductive layer includes:

[0018] A conductive layer is provided, which is composed of at least a first metal layer and a second metal layer stacked together; wherein the first metal layer is disposed on a carrier plate, the second metal layer is disposed on the first metal layer, the roughness Ra1 of the functional surface of the first metal layer is 0.3 μm to 0.5 μm, and the roughness Ra2 of the functional surface of the second metal layer is 0.02 μm to 0.3 μm;

[0019] Composite substrate and conductive layer.

[0020] In some possible implementations, providing a conductive layer composed of at least a first metal layer and a second metal layer stacked together further includes patterning the conductive layer according to a pre-fabricated circuit pattern, enabling the conductive layer to be matched with the cell electrodes or pad points in subsequent processes to achieve effective conductive connection. This patterning process can be completed in advance and then the patterned conductive layer is laminated to the carrier substrate. Alternatively, in some implementations, the stacked conductive layer can be laminated to the carrier substrate first, and then the conductive layer carried on the carrier substrate can be patterned.

[0021] In some possible implementations, the roughness treatment process and scheme disclosed in this application are used to process specific edge regions (first regions) of the first effective area of ​​the functional surface of the first metal layer or specific edge regions (second regions) of the second effective area of ​​the functional surface of the second metal layer, so that the roughness Ra3 of the corresponding first region is 0.3μm to 100μm and the roughness Ra4 of the second region is 0.02μm to 80μm. This technical solution facilitates the subsequent process of stripping the ineffective areas (waste areas) of the conductive layer, providing stripping efficiency and effectiveness. In some implementations of this application, based on the high safety requirements of photovoltaic module products, the laser processing process, doping process, and spraying of insulating materials disclosed in this application can be used to process the edge regions and side surface regions of the effective area of ​​the conductive layer to improve the volume resistivity of these regions. Furthermore, the laser engraving process or chemical engraving process disclosed in this application can be used to process these regions with an inwardly concave corrugated structure to further effectively improve the electrical isolation performance of adjacent effective areas of the conductive layer, thereby improving the electrical safety requirements of the conductive backsheet and enhancing the safety of photovoltaic modules using conductive backsheets. In the production process of conductive backplanes where production rhythm and process design are coordinated, the patterning process, roughness treatment process, volume resistivity treatment process, and process of setting concave corrugated body structure disclosed in this application can be reasonably adjusted in operation sequence, merged, and the aforementioned conductive layer treatment process or technology can be completed in the same process using the same or similar technical means, thereby reducing the production cost per unit time, improving production efficiency, and also improving the reliability of the backplane and the products using the backplane.

[0022] Thirdly, this application also provides a photovoltaic module, including a conductive backsheet as described in any of the preceding claims. This photovoltaic module has the same beneficial effects as the conductive backsheets described in the first aspect and any of the preceding claims, and will not be repeated here.

[0023] The conductive backsheet, manufacturing method, and photovoltaic module using the conductive backsheet disclosed in this application are comprehensive technical solutions that synergistically improve product reliability, photoelectric conversion efficiency, reduce production costs, and increase production efficiency. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 is a schematic diagram of a structure combining a conductive backplate and a battery cell according to an embodiment of this application;

[0026] Figure 2 is a schematic diagram comparing the reflectance of the low-roughness copper foil in the embodiment of this application with that of conventional roughness copper foil;

[0027] Figure 3 is a top view of a portion of a conductive backplate according to an embodiment of this application.

[0028] Figure 4-1 is a schematic diagram of a pre-patterned or patterned conductive layer of a conductive backplate according to an embodiment of this application (view from the second metal layer).

[0029] Figure 4-2 is a schematic diagram of the pre-patterned or patterned conductive layer of the conductive backplate in another embodiment of this application (view from the first metal layer).

[0030] Figure 5 is a partial three-dimensional cross-sectional view of the conductive layer in the conductive backplate of Figure 4-1 along the AA direction.

[0031] Figure 6 is a schematic diagram of the concave wave structure provided on the effective area of ​​the conductive layer in an embodiment of this application.

[0032] Figure 7 is a schematic flowchart of a method for manufacturing a conductive backplane provided in this application.

[0033] Reference numerals in the attached figures: 1 is the carrier plate, 2 is the conductive layer, 21 is the first metal layer, 211 is the first effective area, 2111 is the first area, 22 is the second metal layer, 221 is the second effective area, 2211 is the second area, 23 is the third area, 24 is the ineffective area, 3 is the adhesive film, 31 is the opening, and 4 is the battery cell. Specific Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0035] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0036] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0037] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0038] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0039] In the description of this application, the terms "layer," "plate," and "film" can be used interchangeably in a broad sense. The carrier plate in this application can be a polymer-based plate with or without an adhesive film, or a glass plate with flow properties under specific processes. The carrier plate can be selected as transparent, translucent, or opaque depending on the application requirements, and the carrier plate must at least have insulating properties under certain conditions.

[0040] The conductive layer in this application can be a metal conductive layer such as copper foil, aluminum foil, or zinc foil, or it can be a doped metal foil such as copper foil or aluminum foil containing doping elements such as nickel.

[0041] In the description of this application, unless otherwise specified, the terms "mapping area," "corresponding area," or "projection area" used in this application have the same or similar meaning, namely, the orthographic projection of a component, material, or location onto another area. The terms "pre-set," "reserved," "prefabricated," or "pre-designed" used in this application do not require explicit marking on the conductive backplate or conductive layer during the manufacturing process of the conductive backplate or the processing of the conductive layer disclosed in this application.

[0042] In the description of this application, as shown in Figure 3, the conductive layer can be patterned (or graphicized) according to a pre-designed pattern using various processes or techniques, such as laser die-cutting, mechanical die-cutting, chemical etching, milling, etc. The conductive layer can be divided into effective and ineffective regions according to the pre-designed pattern (or a pre-defined circuit pattern, prefabricated circuit pattern, pre-designed pattern, etc., which have the same or equivalent meaning) or patterning. Both effective and ineffective regions can be composed of multiple small regions (i.e., small units) with the same or similar patterns. In this application, the effective region can also be referred to as a conductive region, effective unit, effective region unit, bus conductive layer, or other names that have the same, equivalent, or similar function as the effective region of this application; the ineffective region can be referred to as a pre-removal region, removal region, removal area, removal channel, ineffective region unit, or other names that have the same, equivalent, or similar function as the ineffective region of this application.

[0043] In the description of this application, unless otherwise specified, the numerical range disclosed in this application includes the stated number, and when the roughness, volume resistivity, etc. are tested or calculated based on a surface or volume, such data are average data.

[0044] This application discloses a conductive backsheet, including a carrier plate and a patterned conductive layer. The conductive layer can be a metal layer disposed on the carrier plate, and the surface roughness Ra of the functional surface of the conductive layer for electrical contact with the solar cell is 0.02 μm to 0.3 μm. In this technical solution, the surface roughness of the functional surface of the conductive layer for contact with the solar cell differs from conventional requirements. By reducing the roughness Ra to 0.02 μm to 0.3 μm, the reflectivity of the conductive backsheet is improved, resulting in better light absorption by the solar cell under illumination and enhanced photoelectric conversion efficiency. Furthermore, since the manufacturing process of photovoltaic modules requires the use of conductive adhesive to connect the conductive layer and the solar cell, the design of the surface roughness of the conductive layer is closely related to the efficient introduction and effective function of the conductive adhesive in subsequent processes. The surface roughness of the conductive layer designed in this application can promote the flow of the conductive adhesive in the molten state and increase the bonding area of ​​the two sides of the molten conductive adhesive (the conductive layer and the solar cell, respectively), thereby improving the efficiency and reliability of the conductive adhesive process. It also reduces the stress between the conductive adhesive and the solar cell and the conductive layer, thus preventing the solar cell from developing microcracks due to high stress.

[0045] In specific embodiments, the surface roughness Ra of the functional surface of the conductive layer used for electrical contact with the solar cell can be 0.02μm, 0.03μm, 0.04μm, 0.06μm, 0.08μm, 0.1μm, 0.12μm, 0.14μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.26μm, 0.28μm, 0.3μm, etc. The specific roughness parameters can be selectively adjusted or designed based on the fluidity and other properties of the conductive molten adhesive and adhesive film selected in subsequent processes. Considering both the promotion of light absorption in the photovoltaic module or component and the effects of subsequent conductive molten adhesive and adhesive film (based on the current and foreseeable performance of the conductive molten adhesive and insulating adhesive film), in some embodiments, Ra can be 0.05μm to 0.3μm; further, Ra can be 0.1μm to 0.3μm, with a preferred value of 0.15μm.

[0046] Based on the foregoing embodiments, as shown in Figures 1 and 3, this application provides a conductive backplane, including a carrier plate 1 and a patterned conductive layer 2; wherein, the conductive layer 2 includes at least a first metal layer 21 and a second metal layer 22 stacked together, the first metal layer 21 is disposed on the carrier plate 1, and the second metal layer 22 is disposed on the first metal layer 21. The first metal layer 21 and the second metal layer 22 can be joined together by mechanical pressing, or the second metal layer 22 can be plated on the first metal layer 21 by electroplating. When there are other metal layers, they can also be joined together in the same way. The surface roughness Ra1 of the functional surface of the first metal layer 21 is 0.3 μm to 0.5 μm (specifically, it can be 0.3 μm, 0.31 μm, 0.32 μm, 0.33 μm, 0.34 μm, 0.35 μm, 0.36 μm, 0.37 μm, 0.38 μm, 0.39 μm, 0.4 μm, 0.41 μm, 0.42 μm, 0.43 μm, 0.44 μm, 0.45 μm, 0.46 μm, 0.47 μm, 0.48 μm, 0.49 μm, 0.5 μm, etc.). It should be noted that the functional surface of the first metal layer 21 is the side that contacts the carrier plate 1, and the roughness of the other surfaces of the first metal layer 21 may be the same as or different from that of the functional surface; the roughness Ra2 of the functional surface of the second metal layer 22 is 0.02μm to 0.3μm, and the functional surface of the second metal layer 22 is the side away from the carrier plate 1, that is, the side used to make electrical contact with the battery cell 4 (corresponding to the functional surface of the conductive layer in the aforementioned embodiment used to make electrical contact with the battery cell), and the roughness of the other surfaces of the second metal layer 22 may be the same as or different from that of the functional surface. In the conductive backsheet product, the roughness Ra2 in this embodiment is 0.02μm to 0.3μm (it can be 0.02μm, 0.03μm, 0.04μm, 0.06μm, 0.08μm, 0.1μm, 0.12μm, 0.14μm, 0.16μm, 0.18μm, 0.2μm, 0.22μm, 0.24μm, 0.26μm, 0.28μm, 0.3μm, etc.). In practical embodiments, as mentioned above, it can be adjusted or designed in conjunction with the light absorption of photovoltaic products and the effect of subsequent colloidal films. In some preferred embodiments, Ra2 can be 0.05μm to 0.3μm; further, the preferred value of Ra2 can be 0.15μm.From the perspective of parameter measurement of conductive backsheet products and photovoltaic products including them, the measurement of the functional surface Ra2 of the second metal layer 22 can be achieved by measuring the substantial area of ​​the second effective region 221 of the second metal layer 22. This substantial area can be the region in the conductive layer 2 that is not in direct conductive contact with the solar cell 4, such as the effective region in contact with the adhesive film 3, excluding the region connected by a specific conductive adhesive. In conductive backsheet products, this substantial area can also be the majority or large area after removing the specially treated region (which can be the region with attached conductive adhesive, or the second region treated with roughness, volume resistivity, and concave structure in the following embodiments). Similarly, in conductive backsheet products, the roughness of the functional surface of the first metal layer 21 in this embodiment is 0.3μm to 0.5μm, which can be achieved by measuring the substantial area of ​​the first effective region 211 of the first metal layer 21. This substantial area can also be the majority or large effective region after removing the first region mentioned in the following embodiments. The surface (or region) roughness value range disclosed in this application refers to the average roughness value range of that surface or region. An exemplary testing method is as follows: Take a point on the surface as the center point, and radiate outwards with a radius of a certain distance (e.g., 0.5 cm) around that center point to determine the high and low points of the radiated area. Then, use a certain algorithm to take the average value to determine the average roughness value of the radiated area. It should be noted that the roughness testing method disclosed in this application is only one example; currently, there are various roughness testing instruments and methods that can be applied to the roughness control and testing in the embodiments of this application.

[0047] In the above technical solution, the conductive backsheet uses a first metal layer 21 and a second metal layer 22 stacked together. The functional surface of the first metal layer 21, which contacts the carrier plate 1, has a high roughness Ra1, ranging from 0.3 μm to 0.5 μm. This high roughness allows for stronger adhesion between the functional surface of the first metal layer 21 and the carrier plate 1, thereby improving the reliability of the photovoltaic module. After the photovoltaic module completes reliability testing under high temperature and humidity conditions, it is less likely to experience localized damage due to insufficient adhesion. The roughness Ra2 of the functional surface of the second metal layer 22, which is used for electrical contact with the solar cell 4, differs from the conventional high roughness requirement aimed at achieving high adhesion. Instead, it is reduced to 0.02 μm to 0.3 μm to improve the reflectivity of the conductive backsheet, resulting in better light absorption by the solar cell under illumination and improved photoelectric conversion efficiency. Furthermore, in the manufacturing process of photovoltaic modules using conductive backsheets, a step is required to connect the conductive layer and the solar cell using conductive adhesive. The design of the surface roughness of the second metal layer 22 is closely related to the effective introduction and efficient function of the conductive adhesive in subsequent processes. In this application, the surface roughness of the second metal layer 22 can both promote the flow of the conductive adhesive in its molten state and increase the bonding area of ​​the two sides of the adhesive after the molten conductive adhesive has solidified (the functional surface of the second metal layer 22 and the solar cell 4, respectively). This improves the flow introduction efficiency of the molten conductive adhesive between the solar cell 4 and the second metal layer 22 and the reliability of the conductive adhesive. It can also reduce the stress between the conductive adhesive and the solar cell 4 and the second metal layer 22, avoiding microcracks in the solar cell 4 due to high stress. In addition, since the conductive layer 2 uses at least the first metal layer 21 and the second metal layer 22, the selection range of materials for the conductive layer 2 is expanded. Materials can be rationally selected based on their conductivity and cost, resulting in the conductive layer 2 having good conductivity while reducing costs. The conductive backsheet of this application, as an integrated design, achieves the effects of high photovoltaic cell conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability.

[0048] Figure 3 is a top view of a conductive backsheet according to an embodiment of this application (viewed from the second metal layer 22). Viewed downwards from the direction of the second metal layer 22, the second metal layer 22 may be covered with an adhesive film 3. The conductive layer 2 is patterned according to a pre-designed circuit pattern. During or after patterning, the conductive layer 2 is divided into effective areas and de-waste areas (ineffective areas 24), with the de-waste areas isolating adjacent effective area units. Patterning can be performed by die-cutting from the functional surface of the first metal layer 21, peeling off the de-waste areas from the functional surface of the first metal layer 21 to complete the patterning process; patterning can also be performed by die-cutting from the functional surface of the second metal layer 22, peeling off the de-waste areas from the functional surface of the second metal layer 22 to complete the patterning process. In some embodiments, openings 31 can be pre-formed in the adhesive film of the conductive backsheet according to the electrode pattern of the battery cell to be matched later. During subsequent component manufacturing, conductive adhesive can be introduced into the openings 31 to electrically connect the conductive layer 2 to the battery cell. Based on the above embodiments, in some embodiments, a specific area of ​​the functional surface of the conductive layer 2 (first metal layer 21 or second metal layer 22) (the functional surface of the conductive layer 2 includes the functional surface of the first metal layer 21 and the functional surface of the second metal layer 22) can be roughened. The aforementioned specific area can be an area that spreads into the effective area from the intersection line of the effective area and the adjacent ineffective area 24 (this intersection line can also be called the boundary of the effective area; unless otherwise specified, the expression in other places in this application has the same meaning as the expression here). Generally, it should not spread to the position of the conductive adhesive application point reserved in the effective area of ​​the conductive layer 2 (corresponding to the opening 31 area of ​​the adhesive film 3). In this application, for the sake of clarity in explaining the technical solution, the application point or attachment area of ​​the conductive adhesive introduced in the subsequent component manufacturing process on the conductive layer 2 is referred to as the reserved point of the conductive backsheet. However, it should be noted that in the manufacturing process of the conductive backsheet disclosed in this application, especially during the various processing steps of the conductive layer, it is not required to mark the reserved point on the conductive layer 2. Depending on the front and back orientations of the patterned conductive layer intervention or the front and back orientations of the intervention in the ineffective peeling region 24, different treatments can be applied to specific areas of the aforementioned conductive layer 2, namely:

[0049] (1) In some embodiments, when the conductive layer 2 is patterned according to the pre-designed circuit pattern from the functional surface of the first metal layer 21, or when the invalid region 24 of the conductive layer 2 is peeled off from the functional surface of the first metal layer 21, as shown in FIG4-2, the roughness Ra3 of the first region 2111 of the functional surface of the first metal layer 21 (in this embodiment, the first region 2111 is the aforementioned specific region of the conductive layer 2) is processed to 0.3μm~10. 0μm (can be 0.3μm, 0.31μm, 0.4μm, 0.45μm, 0.5μm, 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.). As shown in Figure 4-2, the first region 2111 is a specific edge region of each first effective region 211, and depending on the design number of first effective regions 211, there can be multiple first regions 2111. In this embodiment, the first region 2111 is the area where the intersection line between each first effective region 211 of the conductive layer 2 and the adjacent ineffective region 24 begins to extend towards the first effective region 211. Generally, the first region 2111 should not extend to the reserved point of the conductive backplate in the mapping area of ​​the first metal layer 21. Considering the current size of the battery cell and the design parameters such as the electrodes, in some preferred embodiments, the extension distance of the first region 2111 is 10μm-100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.). The specific value selection or design can be adapted to the size of the battery cell, electrode and other parameters.

[0050] The roughness treatment of the first region 2111 allows the stripping device to enhance the contact force with the conductive layer 2 during the conductive layer patterning process, so as to efficiently strip the ineffective region 24 between two adjacent effective regions, which facilitates the completion of the waste removal process. The stripping device can be an adsorption stripping device, a mechanical tearing stripping device, or other stripping devices that require the use of roughness to enhance contact. In some embodiments, depending on the currently or anticipated stripping device used, the roughness Ra3 of the first region 2111 can be processed to be 0.45μm to 100μm, specifically 0.45μm, 0.5μm, 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc. The specific value selection or design can be synergistically designed according to the device used in the conductive layer patterning process (e.g., laser engraving device, stripping device, etc.) and the propagation distance of the first region 2111. In a preferred embodiment, the roughness Ra3 of the first region 2111 can gradually decrease in the direction of propagation from the boundary of the invalid region to the effective region (that is, the propagation direction of the first region 2111 in the aforementioned embodiment). For example, in the range of 0.45μm-100μm, the roughness of the first region in the direction from the boundary of the invalid region to the effective region gradually decreases from 100μm to 0.45μm.

[0051] (2) In some embodiments, when the conductive layer 2 is patterned according to a pre-designed pattern at the functional surface of the second metal layer 22, or when the invalid region 24 of the conductive layer 2 is peeled off at the functional surface of the second metal layer 22, as shown in Figures 3 and 4-1, the roughness Ra4 of the second region 2211 of the functional surface of the second metal layer 22 is 0.02 μm to 80 μm (it can be 0.02 μm, 0.03 μm, 0.04 μm, 0.5 μm, 1 μm, 5 μm, 1... The sizes of the second metal layer 22 functional surface are 0μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 77μm, 79μm, 80μm, etc. In this embodiment, the second region 2211 of the second metal layer 22 functional surface is the specific edge region of each of the aforementioned second effective regions 221. Depending on the design number of second effective regions 221, there can be multiple second regions 2211. In this embodiment, the second region 2211 of the second metal layer 22 functional surface is the region where the intersection line between each second effective region 221 of the conductive layer 2 and the adjacent ineffective region 24 begins to extend towards the second effective region 221. Generally, the extension distance of the second region 2211 does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer 22. Based on the current dimensions of the solar cell and electrode design parameters, in the preferred embodiment, the distance between the spread region and the intersection line of the second effective region 221 and the adjacent ineffective region 24 is 10μm-100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.). The specific value selection or design can be adapted to the dimensions of the solar cell, electrode parameters, etc.

[0052] As described in (1) above, the treatment of the roughness Ra4 of the second region 2211 can enhance the contact force between the stripping device and the conductive layer 2 during the patterning process of the conductive layer so as to efficiently strip the ineffective region 24 between two adjacent effective regions, which facilitates the completion of the waste removal process. The stripping device can be an adsorption stripping device, a mechanical tearing stripping device, or other stripping devices that require the use of roughness to enhance contact. In some embodiments, depending on the currently or anticipated stripping device used, the roughness Ra4 of the second region 2211 can be processed to be 0.15μm-80μm, specifically 0.15μm, 0.3μm, 0.5μm, 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 77μm, 79μm, 80μm, etc. The specific value selection or design can be coordinated with the device used in the conductive layer patterning process (e.g., laser engraving device, stripping device, etc.) and the propagation distance of the second region 2211. In a preferred embodiment, the roughness Ra4 of the second region 2211 can gradually decrease in the direction of propagation from the boundary of the invalid region to the effective region (that is, the propagation direction of the second region 2211 in the aforementioned embodiment). For example, in the range of 0.15μm-80μm, the roughness of the second region in the direction from the boundary of the invalid region to the effective region gradually decreases from 80μm to 0.15μm.

[0053] The roughness design and processing of the first region 2111 of the first metal layer 21 or the second region 2211 of the second metal layer 22 in the embodiments of (1) and (2) above facilitates effective contact between the stripping device and the conductive layer 2 during the conductive layer patterning process and enables efficient stripping of the ineffective region 24 between two adjacent effective regions, thus facilitating the completion of the waste removal process. The stripping device can be an adsorption stripping device, a mechanical tearing stripping device, or other stripping device that requires roughness to enhance contact. It should be noted that in some conductive backplate manufacturing processes with reasonable production cycles and process designs, the roughness processing of the first region 2111 and the patterning process of the conductive layer 2, or the roughness processing of the second region 2211 and the patterning process of the conductive layer 2, can be completed in the same process and / or using the same or identical process.

[0054] Based on the independent embodiments within the scope of this application or one or more of the foregoing embodiments, as shown in FIG5, the roughness of the third region 23 of the conductive layer 2 can be processed to be 0.1μm to 80μm (which can be 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 77μm, 78μm, 79μm, 80μm, etc.). The third region... 23 is a side region (i.e., the side surface region of the effective region of the conductive layer 2) formed between each effective region of the patterned or patterned conductive layer 2 and the adjacent ineffective region 24. This side region is located between the functional surfaces of the first metal layer 21 and the second metal layer 22. Since the conductive layer 2 is composed of at least the first metal layer 21 and the second metal layer 22 stacked together, the third region 23 includes two stacked parts, namely the side region of the first metal layer 21 and the side region of the second metal layer 22. The roughness of the side region of the first metal layer 21 and the roughness of the side region of the second metal layer 22 can be the same or different. The electrical isolation performance between adjacent effective region units of the conductive layer 2 of the conductive backsheet determines the safety of the conductive backsheet and the module using the conductive backsheet. Incomplete waste removal, bubbles, and other reasons can easily cause adjacent effective region units to connect, resulting in a short circuit in the photovoltaic module, thereby affecting the reliability of the photovoltaic module. The roughness treatment of the third region 23 of the conductive layer 2 in this embodiment of the application enables the adhesive fluid to flow to the ineffective region 24 (or ineffective channel) of the conductive layer 2 in the subsequent bonding process of the conductive layer 2 and the carrier plate 1 (or the bonding process of the carrier plate 1, the conductive layer 2 and the adhesive film 3), that is, when it flows to the adjacent effective region units, so that the third region 23 can better coat the adhesive fluid, or provide the adhesive force between the adhesive film and the third region 23, so that the adhesive fluid can effectively and completely fill the waste area in the conductive backsheet bonding process, thereby effectively isolating the adjacent effective region units of the conductive layer 2, improving the reliability of the conductive backsheet and the photovoltaic module using the conductive backsheet.In some embodiments, the roughness of the third region 23 can be between 0.1 μm and 80 μm, preferably between 3 μm and 80 μm (which can be 3 μm, 4 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 77 μm, 78 μm, 79 μm, 80 μm, etc.); in some preferred embodiments, depending on the apparatus used in the current and foreseeable patterning process and the performance of the subsequent adhesive film, the roughness of the third region 23 can be between 3 μm and 40 μm (which can be 3 μm, 4 μm, 5 μm, 8 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 38 μm, 39 μm, 40 μm, etc.). It should be noted that the roughness of the third region 23 can be designed according to the variations in the melting temperature, curing temperature, flow properties, and basis weight of the adhesive film 3 disposed on the carrier plate 1 (or the carrier plate 1) and / or the second metal layer 22 (especially for adhesive films with new materials or new properties in the future). It should also be noted that in some preferred embodiments, the roughness treatment of the third region 23 and the patterning process of the conductive layer 2 can be completed in the same step and / or using the same or identical process.

[0055] The design of the functional surface roughness of the conductive layer, the design of the edge roughness of the effective area of ​​the conductive layer, and the design of the roughness of the first, second, and third areas of the conductive metal layer disclosed in the foregoing embodiments not only consider the reliability of the conductive backsheet and photovoltaic module, but also the photoelectric conversion efficiency of the photovoltaic module, the unit time cost, and take into account the composite of the conductive backsheet, the cycle time of the photovoltaic module production process, and the overall production efficiency. It provides an overall design scheme that achieves the effect of high photovoltaic cell conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability.

[0056] Based on the independent embodiments within the scope of this application or one or more of the foregoing embodiments, and while simultaneously improving the photoelectric conversion efficiency of photovoltaic modules, reducing the cost of conductive backsheets, and increasing production efficiency, to enhance the electrical safety of the conductive backsheet, as shown in Figures 3 and 5, some embodiments of this application provide a conductive backsheet whose conductive layer 2 includes an effective region, an ineffective region 24, and a side surface (third region 23) of the effective region of the conductive layer. The second effective region 2211 and the third region 23 of the second metal layer 22 are subjected to volume resistivity treatment, such that the volume resistivity of the second region 2211 is greater than that of the remaining regions of the second effective region 221, and the volume resistivity of the third region 23 is greater than that of the remaining regions of the conductive layer 2. It should be noted that the first region 2111, the second region 2211, and the third region 23 mentioned in this application have a certain thickness and a measurable volume resistivity. In this embodiment, the second region 2211 is the region that extends from the boundary of the second effective region 221 (i.e., the intersection line of the second effective region 221 and the adjacent ineffective region 24, the description in other places in this application is the same as the explanation here) to the aforementioned same second effective region 221. Generally, the extension distance of the second region 2211 does not exceed the mapping or projection area of ​​the reserved points of the conductive backplate on the second effective region 221. Based on this embodiment, the technical solution of this embodiment is now described as follows according to the layer structure of the conductive layer 2:

[0057] As shown in Figure 1, the conductive layer 2 includes a first metal layer 21 and a second metal layer 22. As shown in Figure 4-1, the effective region is the second effective region 221 of the second metal layer 22. The second effective region 221 includes the second region 2211 of the functional surface of the second metal layer 22 and the remaining region of the second metal layer 22. That is, the effective region on the second metal layer 22 includes not only the second region 2211 of the functional surface of the second metal layer 22, but also the remaining region of the second metal layer 22 (excluding the invalid region 24). The second region 2211 is the region that extends from the boundary of the second effective region 221 of the second metal layer 22 to the second effective region 221. Generally, the extension distance of the second region 2211 does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer 22. As shown in Figure 4-2, the effective region is the first effective region 211 of the first metal layer 21. The first effective region 211 includes the first region 2111 of the functional surface of the first metal layer 21 and the remaining regions of the first metal layer 21. That is, the effective region on the first metal layer 21 includes not only the first region of the functional surface of the first metal layer 21, but also the remaining regions of the first metal layer 21 (excluding the invalid region 24). The first region 2111 is the region that extends from the boundary of the first effective region 211 of the first metal layer 21 to the first effective region 211. Generally, the extension distance of the first region 2111 does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer 21. In a preferred embodiment, the distance by which the first region 2111 and the second region 2211 extend from the effective region boundary of their respective metal layers toward the effective region is 0.1 μm-20 mm (specifically, it can be 0.1 μm, 0.5 μm, 1 μm, 3 μm, 5 μm, 7 μm, 9 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc.). As mentioned in the previous embodiments, the preferred extension distance can be 10 mm. μm-100μm (can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.), and the specific value selection or design can be adapted to the size of the battery cell, electrode parameters, etc. In this embodiment, the bulk resistivity of the third region 23 can also be processed so that the bulk resistivity of the third region 23 is greater than the bulk resistivity of the other regions of the conductive layer 2.Based on the aforementioned improvement of the volume resistivity of the third region 23, at least one region of the first region 2111 of the first metal layer 21 and the second region 2211 of the second metal layer 22 can be further processed to increase the volume resistivity of that region to be correspondingly greater than that of the remaining regions of the first metal layer 21 (i.e., regions other than the first region 2111 and the third region 23) and the remaining regions of the second metal layer 22 (i.e., regions other than the second region 2211 and the third region 23). The technical solution of this embodiment improves the volume resistivity of the side surfaces and edge regions of the effective regions of the conductive layer by processing specific regions on the sides and upper and lower surfaces, thereby improving the electrical isolation performance of adjacent effective regions of the conductive layer and enhancing the safety and reliability of the photovoltaic conductive backsheet and the components using the conductive backsheet. It should be noted that there are various methods for treating the volume resistivity of these regions. For example, CVD (Chemical Vapor Deposition) or PECVD (Plasma Enhanced Chemical Vapor Deposition) can be used to dope specific regions at the edge of the effective area of ​​the conductive layer 2 with group V or group VI elements, and corrosion-resistant insulating materials can be sprayed onto these regions. This application discloses several exemplary treatment methods:

[0058] (1) Insulating materials such as alumina ceramics and ceramic polymers can be sprayed onto these specific areas; in a preferred embodiment, when using a laser to pattern the conductive layer, a spraying device can be set at the laser head position to achieve simultaneous spraying of alumina ceramic materials during the laser patterning process. The spraying area is controlled to extend from the effective area boundary of the conductive layer to the effective area by 0.1μm-20mm, preferably with a spraying range of 5mm; in embodiments using advanced spraying devices, in particular, the spray nozzle can achieve For micron-level control, the preferred spraying range is 10μm-100μm (specifically, it can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, etc.). The specific value selection or design can be adapted to parameters such as the size of the solar cell, the electrodes, and the control performance of the spraying device.

[0059] (2) Alternatively, a patterned conductive layer made of copper foil can be placed on a prefabricated grid plate, exposing specific regions at the edge of the effective area of ​​the conductive layer (e.g., including the first region 2111, the second region 2211, and the third region 23) to the grid, while other regions of the effective area are shielded by the plate structure of the grid plate. Then, the grid plate carrying the conductive layer is placed in a reaction vessel, and sulfides and phosphides (e.g., phosphorus hypochlorite POCl3, etc.) are deposited on the specific area using CVD chemical vapor deposition to form a compound film containing sulfur and copper, phosphorus and copper, or phosphorus, sulfur, and copper on the specific area.

[0060] (3) In a preferred embodiment, the patterning of the conductive layer and the volume resistivity treatment of a specific area at the edge of the effective region of the conductive layer can be completed in the same process. This application exemplarily discloses a technical solution that combines the patterning and volume resistivity treatment processes using a laser processing technique: when the conductive layer 2 is composed of two metal layers stacked together, the first metal layer 21 is aluminum foil and the second metal layer 22 is copper foil, and the thickness of the conductive layer 2 ranges from 40μm to 60μm, the laser parameters can be selected based on the pre-made circuit pattern, the thickness and material of the conductive layer 2, and the range of the first region 2111 and the second region 2211 of the effective region of the conductive layer 2. For the conductive backplate disclosed in the above embodiment of this application where the range of the first region 2111 and / or the second region 2211 is 10μm-100μm, a frequency range of 50-500Hz can be selected. The diameter of the circular laser spot is 10μm-100μm (it can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.), preferably 50μm. The laser operates at a speed range of 1000-20000mm / s and a power range of 100%. The conductive layer 2 is laser-engraved and sintered in an environment with a temperature of 5-55 degrees Celsius, a pressure of 0.5-2 atmospheres, and an oxygen content of 10%-30% of the total gas.

[0061] Based on the above embodiments, in some embodiments, the conductive layer 2 of the conductive backplane disclosed in this application uses a resistivity of 1.65 × 10⁻⁶. -8 Ωm-5×10 -8 The bulk resistivity of the metal layer in the Ωm range, specifically the side surface region of the effective conductive layer (corresponding to the third region 23 in Figure 5) and / or the edge-specific region (corresponding to the second region 2211 in Figure 4-1 and / or the first region 2111 in Figure 4-2), is 3.15 × 10⁻⁶. -8 Ωm-5×10 -8Ωm. The volume resistivity of the side surface region and edge-specific region of the effective conductive layer of the conductive backplane disclosed in this application is at least greater than or equal to that of the remaining regions of the effective region (excluding the side surface region and edge-specific region), thereby improving the electrical isolation performance between adjacent effective regions and enhancing the safety and reliability of the conductive backplane.

[0062] Based on independent embodiments within the scope of this application or one or more of the foregoing embodiments, this application also discloses a conductive backplane, including a carrier plate and a patterned conductive layer; the conductive layer includes active units and inactive units, and the edge-specific regions of the active units include an upper surface, a side surface, and a lower surface; the edge-specific regions are areas that extend from the boundary of the active units into the active units, and the extended region does not exceed the mapping area of ​​the reserved points of the conductive backplane on the conductive layer; at least one of the upper surface, lower surface, and side surface has a wave structure that is concave with the side surface as a reference plane; the wave crests of the wave structure (the wave crests are structures that are far from the side surface or closer to the active region) respectively do not exceed the mapping area of ​​the reserved points of the conductive backplane closest to the inactive units on the conductive layer. Considering the requirements of current and anticipated devices and the electrical isolation performance of the conductive backplane, the height range of the aforementioned wave crests can be designed to be greater than 0 and less than or equal to 2 μm. In the case of this embodiment, the conductive layer includes effective units and ineffective units. The edge of the effective unit includes an upper surface, a side surface, and a lower surface. Applying a concave corrugated structure to at least one of these surfaces effectively improves the electrical isolation performance of adjacent effective units of the conductive layer, thereby improving the electrical safety requirements of the conductive backsheet product and enhancing the safety of photovoltaic modules using the conductive backsheet.

[0063] In conjunction with the aforementioned embodiment of the conductive layer including two metal layers, one embodiment of this application can further process at least one of the first region 2111, the second region 2211, and the third region 23 of the conductive layer 2 in the aforementioned embodiment, so that at least one region has a wave structure that is concave with the third region as the reference plane, and the wave crest of the wave structure does not exceed the mapping area of ​​the reserved point of the invalid region 24 closest to the conductive layer in the conductive backing plate on the conductive layer 2 (that is, the conductive adhesive application point on the effective region closest to the waste removal channel in the conductive backing plate, which can be referred to as the position of the opening 31 of the adhesive film 3 closest to the invalid region 24 shown in FIG3). In a preferred embodiment, the side surfaces of the effective areas of the conductive layer (corresponding to the third region 23 in Figure 5) and the edge-specific regions (corresponding to the second region 2211 in Figure 4-1 and / or the first region 2111 in Figure 4-2) can be structurally processed to give the aforementioned effective area side surfaces and edge-specific regions (which can be the first region 2111 and / or the second region 2211) a concave wave structure, and the peaks of the wave structure do not exceed the mapping area of ​​the reserved point of the invalid region 24 closest to the conductive layer 2 on the conductive backplate. In a further preferred embodiment, as shown in Figure 6, staggered concave wave structures can be provided on the two opposite side surfaces (i.e., the third region 23) of adjacent second effective regions 221. It should be noted that the "wave structure" here is only a generalization of the shape of the concave structure. The concave structure can also be a pyramid or similar shape. The concave wave structure can be continuous or dispersed, and can be regular or irregular. The technical solution of this embodiment can increase the electrical isolation distance of adjacent second effective regions 221 by setting a concave structure in a specific area on the side surface and / or edge of the second effective region 221, based on the determined width of the invalid region 24 (i.e., the interval distance between adjacent second effective regions 221, which can also be called the electrical isolation distance) or without changing the design width of the invalid region 24, thereby improving the safety of the conductive backplate.

[0064] Based on the above embodiments or in some independent embodiments within the scope of this application, the roughness Ra1 of the functional surface of the first metal layer 21 is not equal to the roughness Ra2 of the functional surface of the second metal layer 22. And / or, the material of the first metal layer 21 is different from the material of the second metal layer 22. Since the materials of the first metal layer 21 and the second metal layer 22 are different, the second metal layer 22, which is used for electrical contact with the battery cell 4, can be made of a material with better conductivity, while the first metal layer 21, which is in contact with the carrier plate 1, can be made of a material with lower cost, thereby satisfying both the good conductivity of the conductive layer 2 and reducing the unit material cost. Based on the synergistic effect of improving the bonding reliability between the conductive layer 2 and the carrier plate 1 and improving the reflectivity of the second metal layer 22, thereby improving the photoelectric conversion efficiency, and improving the efficiency and reliability of the conductive adhesive process, Ra1 and Ra2 are chosen to be unequal. In some embodiments of this application, the conductive layer can be a metal conductive layer such as copper foil, aluminum foil, or zinc foil, or a doped metal foil such as copper foil or aluminum foil containing doped elements such as nickel. For example, the first metal layer 21 can be aluminum foil (including doped aluminum foil), and the roughness Ra1 of the functional surface of the aluminum foil is 0.3μm to 0.5μm, specifically 0.3μm, 0.35μm, 0.4μm, 0.45μm, 0.5μm, etc. The second metal layer 22 can be copper foil (including doped copper foil), and the roughness Ra2 of the functional surface of the copper foil is 0.05μm to 0.2μm, specifically 0.05μm, 0.1μm, 0.15μm, 0.2μm, etc. The copper foil can be rolled onto the aluminum foil, or copper can be electroplated onto the aluminum foil. Using aluminum foil for the first metal layer 21 that contacts the carrier plate 1 reduces the cost of the conductive layer 2. Using copper foil for the second metal layer 22 that makes electrical contact with the solar cell 4 improves the conductivity with the solar cell 4. The surface roughness Ra1 of the aluminum foil is 0.3μm to 0.5μm, which improves the adhesion between the aluminum foil and the carrier plate 1 and enhances the reliability of the photovoltaic module. Meanwhile, the surface roughness Ra2 of the copper foil is 0.05μm to 0.2μm. The low roughness of the copper foil improves reflectivity, which is beneficial for the solar cell to absorb light and improve the photoelectric conversion efficiency. In addition, considering the subsequent conductive adhesive process, the roughness of the surface roughness of the copper foil in contact with the solar cell 4 promotes the fluidity of the adhesive film, increases the bonding area of ​​the two sides of the subsequently molten conductive adhesive, thereby improving the flow introduction efficiency and reliability of the conductive adhesive in the conductive adhesive process, and reducing the stress between the conductive adhesive, the solar cell 4, and the copper foil, thus preventing microcracks in the solar cell 4 due to excessive stress.

[0065] The following comparison of reflectivity and power is made using the second metal layer 22 disclosed in this application, which is a copper foil metal layer with a functional surface roughness of 0.15 μm, as an example, and a copper foil with a functional surface roughness of ≥0.3 μm in the conductive layer of a conventional conductive backplane. The results are shown in Table 1 and Figure 2.

[0066] Table 1. Comparison of power data for 72-panel photovoltaic modules using copper foil with the roughness disclosed in this application and conventional conductive backsheet copper foil.

[0067] As shown in Figure 2, the average surface reflectance of the copper foil in the second metal layer of this application, with a conductive layer roughness of 0.15 μm, is 83.5, while the average surface reflectance of the conductive layer of a conventional conductive backplane with a copper foil roughness equal to or greater than 0.3 μm is 74.0. Clearly, the low-roughness copper foil in this application significantly improves the reflectance. Table 1 shows that by processing the functional surface roughness of the second metal layer copper foil to 0.15 μm, the average power of the same 72-panel photovoltaic module is increased by approximately 2.43 W.

[0068] In some embodiments, the thickness of the conductive layer 2 is 30 μm to 100 μm, specifically 30 μm, 40 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, etc. For example, when the first metal layer 21 is aluminum foil and the second metal layer 22 is copper foil, the thickness of the aluminum foil can be 27 μm to 97 μm, accounting for 80% to 90% of the total thickness of the conductive layer 2; the thickness of the copper foil can be 3 μm to 20 μm, accounting for 10% to 20% of the total thickness of the conductive layer 2. This reduces the unit material cost of the conductive layer 2 while ensuring good conductivity.

[0069] In some embodiments, the tensile strength of the conductive layer 2 is greater than or equal to 200 MPa, and / or the resistivity of the conductive layer 2 is less than or equal to 5 × 10⁻⁶ MPa. -8 Ωm. This conductive layer 2 can simultaneously satisfy sufficient mechanical strength and good electrical conductivity.

[0070] Of course, the conductive layer 2 can also be made of copper-aluminum, aluminum foil, copper foil plated with aluminum, copper foil plated with nickel, copper foil plated with tin, aluminum foil plated with copper, aluminum foil plated with tin, aluminum foil plated with nickel, etc. The first metal layer 21 and the second metal layer 22 can be made of the same or different materials. The appropriate materials can be selected based on conductivity and material cost, thus expanding the range of material choices.

[0071] In some independent embodiments within the scope of this application or based on the embodiments described above, as shown in FIG1, in some embodiments, the conductive backsheet further includes an adhesive film 3 disposed on the second metal layer 22. The second metal layer 22 is connected to the battery cell 4 through the adhesive film 3. The conductive layer 2 and the battery cell 4 are electrically connected by introducing conductive adhesive into the openings 31 provided on the adhesive film 3. That is, the introduction of the adhesive film 3 not only enables the conductive connection between the second effective area 221 on the second metal layer 22 and the corresponding conductive area (which can be a PAD point on the battery cell) on the battery cell 4, but also effectively achieves insulation between different conductive areas of the battery cell 4 in conjunction with the ineffective area 24 (i.e., the waste area) of the conductive layer 2. In addition, the low-roughness second metal layer 22 improves the efficiency of the conductive adhesive process and the reliability of the conductive adhesive, reduces the stress between the conductive adhesive and the battery cell 4 and the second metal layer 22, and avoids microcracks in the battery cell 4 due to high stress.

[0072] As shown in Figure 7, based on the conductive backplane of this application concept or the conductive backplane described in any of the above embodiments, this application embodiment also provides a method for manufacturing a conductive backplane, including the following steps:

[0073] Step S100, as shown in Figure 1, provides a carrier plate 1; the carrier plate 1 can be a thermoplastic material or a glass material with an adhesive layer, etc. The carrier plate 1 can be a multi-layer composite material or a single-layer material, as long as it can be bonded to the conductive layer 2 and has the characteristics of bearing, sealing, corrosion resistance, high temperature resistance, etc., no specific limitation is made here.

[0074] Step S200: Provide a patterned conductive layer; the patterned conductive layer can be referred to the aforementioned relevant description.

[0075] In some embodiments, step S200 may include: providing a conductive layer 2 composed of at least a first metal layer 21 and a second metal layer 22 stacked together; wherein the first metal layer 21 is disposed on a carrier plate 1, the second metal layer 22 is disposed on the first metal layer 21, the surface roughness Ra1 of the functional surface of the first metal layer 21 is 0.3 μm to 0.5 μm, and the surface roughness Ra2 of the functional surface of the second metal layer 22 is 0.02 μm to 0.3 μm. The first metal layer 21 and the second metal layer 22 may be stacked together by mechanical pressing, or the second metal layer 22 may be electroplated onto the first metal layer 21. For a description of the functional surfaces, please refer to the description in the above conductive backplane embodiment, which will not be repeated here. In a preferred embodiment, the roughness of the functional surface of the first metal layer 21 is 0.45 μm, and the roughness of the functional surface of the second metal layer 22 is 0.15 μm. Compared with the prior art, the roughness of the functional surface of the conductive layer is generally greater than or equal to 0.3 μm. This application adopts a comprehensive design scheme that increases the roughness of the functional surface in contact with the carrier plate 1 and reduces the roughness of the functional surface near the battery cell 4. Its technical effect is the same as that described in the above-mentioned conductive backplate embodiment, and will not be repeated here.

[0076] Step S300: Composite carrier 1 and conductive layer 2, wherein the surface roughness Ra of the conductive layer for electrical contact with the battery cell is 0.02μm to 0.3μm; the carrier 1 and conductive layer 2 can be composited by hot pressing or room temperature pressurization, etc., and the contact layer between the carrier 1 and the first metal layer 21 has fluidity for at least a period of time during the composite process.

[0077] The conductive backplate described in the above embodiments can be manufactured using this method, and therefore has the same beneficial effects as the conductive backplate embodiments described above, which will not be repeated here.

[0078] In some embodiments, step S200, which provides a conductive layer 2 composed of at least a first metal layer 21 and a second metal layer 22 stacked together, further includes the step of patterning the conductive layer 2. The patterning process includes die-cutting the conductive layer 2 according to a pre-made circuit pattern (i.e., a pre-designed pattern). Besides laser die-cutting, the patterning process of the conductive layer 2 can also be performed using mechanical die-cutting, chemical etching, milling, etc. In some embodiments, the patterning die-cutting process can be performed by irradiating one side of the first metal layer 21 with a laser of selected frequency, spot size, and speed, or by irradiating one side of the second metal layer 22 with a laser. Thus, by bonding the patterned conductive layer 2 onto the carrier plate 1, damage to the carrier plate 1 by the laser can be avoided, and the laser irradiation direction can be unrestricted from either side of the conductive layer 2. It should be noted that the conductive layer 2 can be patterned first to remove invalid conductive layers before bonding the conductive layer 2 to the carrier plate 1. Alternatively, the unpatterned conductive layer 2 can be bonded to the carrier plate 1 first, and then the conductive layer 2 can be patterned. In this case, in industrial production, it is recommended to pattern the conductive layer 2 from the surface of the second metal layer 22. For example, the patterning of the stacked conductive layer 2 can be completed by irradiating one side of the second metal layer 22 with a laser, or by mechanical cutting according to the pre-made pattern, cutting from the second metal layer 22 to the first metal layer 21 in a direction perpendicular to the surface of the second metal layer 22 or at a certain angle to the surface of the second metal layer 22.

[0079] In some independent embodiments within the scope of this application or based on the above embodiments, step S200 of providing a conductive layer 2 composed of at least a first metal layer 21 and a second metal layer 22 further includes the steps of: roughening a first region 2111 of the functional surface of the first metal layer 21 such that the roughness Ra3 of the first region 2111 is 0.3 μm to 100 μm; or roughening a second region 2211 of the functional surface of the second metal layer 22 such that the roughness Ra4 of the second region 2211 is 0.02 μm to 80 μm. In the method provided in this application embodiment, the conductive layer 2, which is composed of a first metal layer 21 and a second metal layer 22 stacked together, forms an effective region, an ineffective region 24, and a third region 23 during the patterning process; as shown in Figures 4-1 and 4-2, the effective region further includes: a first effective region 211 of the first metal layer 21 and a second effective region 221 of the second metal layer 22; the first effective region 211 of the first metal layer 21 includes the first region 2111 of the functional surface of the first metal layer 21 and the remaining regions of the first metal layer 21 (i.e., the remaining effective regions of the first metal layer 21 excluding the first region 2111), and the second effective region 221 of the second metal layer 22 includes the second region 2211 of the functional surface of the second metal layer 22 and the remaining regions of the second metal layer 22 (i.e., the remaining effective regions of the second metal layer 22 excluding the first region 2211). The roughness treatment of the first region 2111 and the second region 2211 will now be described exemplarily in conjunction with the above description of the regions:

[0080] (1) As shown in Figure 4-2, when the conductive layer 2 is patterned from the surface of the first metal layer 21 according to the pre-designed pattern, or when the invalid region 24 of the conductive layer 2 is peeled off from the surface of the first metal layer 21, the first region 2111 of the functional surface of the first metal layer 21 can be roughened so that the roughness Ra3 of the first region 2111 is 0.3μm to 100μm. Various roughness treatment methods can be used, such as mechanical methods and chemical methods. This application discloses a method that combines patterning of the conductive layer 2 with a thickness range of 40μm to 60μm and specific region roughness treatment using laser engraving when the first region 2111 ranges from 10μm to 100μm. This method can be: selecting a frequency range of 50-500Hz and a spot diameter range of 10μm. A laser with a diameter of 100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.), preferably 50μm, and an operating speed range of 1000-20000mm / s, preferably 6700mm / s, is used to engrave and sinter the conductive layer 2 according to a preset circuit pattern or a preset patterned screen.

[0081] (2) As shown in Figures 3 and 4-1, when the conductive layer 2 is patterned from the surface of the second metal layer 22 according to the pre-designed pattern, or when the invalid region 24 of the conductive layer 2 is peeled off from the surface of the second metal layer 22, the roughness Ra4 of the second region 2211 of the functional surface of the second metal layer 22 is 0.02μm to 80μm. The processing method can refer to the above-described processing of the roughness of the first region 2111 of the first metal layer 21.

[0082] It should be noted that the effective area, invalid area 24, first area 2111, second area 2211 and third area 23 involved in the method disclosed in the embodiments of this application have the same or corresponding descriptions or indications as the areas in the aforementioned embodiments of the conductive backplate, and are corresponding in terms of definition, scope and other limiting factors. Therefore, they will not be repeated in this method description.

[0083] The roughness treatment of the first region 2111 of the first metal layer 21 or the second region 2211 of the second metal layer 22 in the above embodiments facilitates effective contact between the stripping device and the conductive layer 2 during the patterning process and enables efficient stripping of the invalid region 24 located on this region, thus facilitating the completion of the waste removal process. The stripping device can be an adsorption stripping device, a mechanical tearing stripping device, or other stripping device that utilizes roughness to enhance contact. It should be noted that in some preferred embodiments, the roughness treatment of the first region 2111 and the patterning process of the conductive layer 2, or the roughness treatment of the second region 2211 and the patterning process of the conductive layer 2, can be completed in the same process and / or using the same or identical technology.

[0084] In some independent embodiments within the scope of this application or based on the above embodiments, step S200, providing the conductive layer 2 composed of at least a first metal layer 21 and a second metal layer 22, further includes the step of:

[0085] The third region 23 of the conductive layer 2 is roughened to a roughness of 0.1 μm to 80 μm. As shown in Figure 5, the third region 23 is a side region formed between each effective region and adjacent ineffective region 24 of the patterned conductive layer 2. This side region is located between the functional surfaces of the first metal layer 21 and the second metal layer 22. Since the conductive layer 2 is composed of at least the first metal layer 21 and the second metal layer 22 stacked together, the third region 23 includes two stacked parts, namely the side region of the first metal layer 21 and the side region of the second metal layer 22. The roughness of the side region of the first metal layer 21 and the side region of the second metal layer 22 can be the same or different. In some embodiments, the roughness of the third region 23 can be between 0.1 μm and 80 μm, preferably between 3 μm and 80 μm; in some embodiments, the roughness of the third region 23 can be between 3 μm and 40 μm. It should be noted that, in some preferred embodiments, the roughness treatment of the third region 23 and the patterning process of the conductive layer 2 can be completed in the same step and / or using the same or identical process.

[0086] In the above embodiments, the roughness treatment of the functional surfaces of the first metal layer, the second metal layer, specific areas of the effective region, and the side surfaces of the effective region of the conductive layer can be carried out in various ways, including at least one of laser treatment, mechanical treatment, and chemical treatment. For example, mechanical treatment can increase the surface roughness of the first metal layer by means of friction, cutting, and grinding. For instance, using sandpaper or a grinding wheel to process the surface of the first metal layer can increase the roughness of the functional surfaces. Chemical methods, also known as etching, use chemicals such as acids and alkalis to treat the functional surfaces of the first metal layer, which can remove part of the metal surface, forming a rougher surface and thus increasing its surface roughness. In particular, the nitrous oxide method, through a certain nitrogen and oxygen concentration and reaction time, can increase the roughness of the metal surface. Of course, the above roughness treatment methods can also reduce the roughness of the second metal layer, such as mechanical polishing, electrochemical polishing, and chemical mechanical polishing. Mechanical polishing can use mechanical methods such as grinding and abrasive polishing to treat the surface of the second metal layer. By adjusting the polishing agent and polishing machine parameters, its surface roughness can be reduced. Electrochemical polishing involves applying voltage and current to the surface of the second metal layer, triggering a chemical reaction in an ionic solution. This causes ions to detach from the metal surface, achieving a polishing effect. Compared to mechanical polishing, electrochemical polishing can more effectively reduce surface roughness and provides a more uniform surface treatment, avoiding damage or scratches. Chemical mechanical polishing (CMP) is a processing method combining electrochemical and mechanical polishing. It fully utilizes the advantages of electrochemical reactions and mechanical actions, controlling parameters such as polishing agent, polishing pressure, and polishing time to effectively reduce metal surface roughness. It should be noted that in some preferred embodiments, the process of laser-treating the roughness of the first, second, and third regions of the conductive layer can be combined with the laser-patterning process of the conductive layer in the same processing step to simplify the process. Of course, the first, second, and third regions can also be roughened separately, and the roughness treatment methods can include mechanical and chemical methods.

[0087] The design of the functional surface roughness of the conductive metal layer, the design of the roughness of specific areas of the conductive layer, and the design of the roughness of the first, second, and third areas of the conductive metal layer disclosed in the foregoing embodiments not only consider the reliability of the conductive backsheet and photovoltaic module, but also the photoelectric conversion efficiency, unit time cost, and take into account the composite of the conductive backsheet, the cycle time of photovoltaic module production process, and the overall production efficiency. It provides an overall design scheme that achieves the effect of high photovoltaic cell conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability.

[0088] In some independent embodiments of the manufacturing method concept disclosed in this application, or based on the foregoing embodiments, before the composite conductive layer 2 and the carrier plate 1, the manufacturing method further includes the step of: treating the bulk resistivity of the side surface and edge-specific regions (including the edge-specific regions of the upper surface and / or lower surface of the effective region of the conductive layer 2) to make the bulk resistivity of these regions greater than the bulk resistivity of the remaining regions of the effective region. Various methods can be used to treat the bulk resistivity, such as doping these regions with group V or group VI elements, spraying insulating materials such as alumina ceramic onto these regions, or other chemical or physical methods to treat the bulk resistivity of these regions. This application discloses a method for manufacturing the conductive backplate, which is at least composed of a first metal layer and a second metal layer, as disclosed in the foregoing embodiments, using the scheme of this embodiment, as follows:

[0089] The bulk resistivity of the first region 2111 and the third region 23 is greater than that of the remaining regions of the first metal layer 21 (i.e., the regions of the first metal layer 21 excluding the first region 2111 and the third region 23) when treated by laser ablation or chemical reaction; or the bulk resistivity of the second region 2211 and the third region 23 is greater than that of the remaining regions of the second metal layer 22 (i.e., the regions of the second metal layer 22 excluding the second region 2211 and the third region 23) when treated by laser ablation or chemical reaction; or the bulk resistivity of the first region 2111, the second region 2211, and the third region 23 is greater than that of the remaining regions of the conductive layer 2 (i.e., the effective regions of the conductive layer 2 excluding the first region 2111, the second region 2211, and the third region 23) when treated by laser ablation or chemical reaction. The laser can be selected from 50-500Hz, with a circular spot diameter of 10μm-100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.), preferably a laser with a spot diameter of 50μm, to sinter the first region 2111 and / or the second region 2211, and the ineffective region 24. The chemical process can be the CVD, PECVD, or other methods disclosed in the above conductive backplane embodiments to form a sulfur-, phosphorus-, or sulfur-phosphorus compound-containing deposition film in these regions; alternatively, insulating materials such as alumina ceramics can be sprayed onto these regions.

[0090] In some independent embodiments of the manufacturing method concept disclosed in this application, or based on the foregoing embodiments, the preparation method further includes the following steps before the composite carrier 1 and the conductive layer 2:

[0091] At least one of the three regions, namely the first region 2111, the second region 2211, and the third region 23, is processed by laser etching or chemical etching to create a concave wave structure with the third region as the reference plane. The peak of the wave structure does not exceed the mapping area on the conductive layer 2 of the reserved point of the invalid region 24 closest to the conductive layer 2 in the conductive backplane. The laser parameters for etching can be a frequency of 50-500Hz, and the laser spot can be set according to the vertical distance from the conductive adhesive application point closest to the invalid region 24 on the effective region to the boundary line of the effective region (generally, this vertical distance should not be exceeded). Chemical etching can be performed using chemical etchants such as hydrochloric acid or ferric chloride. During the process, the concentration, temperature, and etching time of the chemical etchant are controlled according to the desired size of the concave structure. This can be understood by those skilled in the art through limited experiments based on the set target, selected etchant, reaction time, and environment.

[0092] Based on the concept of this application or the foregoing embodiments, a method for manufacturing the conductive backplate disclosed in the foregoing embodiments, which consists of a first metal layer aluminum foil and a second metal layer copper foil, using the manufacturing method of this application, is disclosed as follows:

[0093] Step 1: Provide a conductive layer 2 composed of aluminum foil and copper foil; this conductive layer 2 can be pre-pressed by mechanical lamination or electroplating to bond the copper foil and aluminum foil together. The surface roughness of the aluminum foil is treated to be 0.45 μm, and the surface roughness of the copper foil is treated to be 0.15 μm. The overall thickness of the copper-aluminum foil conductive layer can be 40 μm-60 μm, preferably 55 μm, and the average volume resistivity of the conductive layer 2 is 3.15 × 10⁻⁶. -8 Ωm.

[0094] Step 2-1: Process the conductive layer 2. The processing procedure is as follows: Based on the conductive layer properties provided in Step 1, select a frequency of 177Hz (or other preferred values ​​within the range of 50Hz-500Hz based on the conductive layer properties), and a circular cursor diameter of 10μm-100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.). Preferably, a 50μm laser is used with a power of 1... At a speed of 1000-20000 nm / s (preferably 6700 nm / s) and a temperature of 5-55 degrees Celsius (preferably 15-40 degrees Celsius), a pressure of 0.5-2 atmospheres (preferably 1 atmosphere), and an oxygen content of 10%-30% of the total gas, the conductive layer 2 is engraved and sintered from the functional surface of the copper foil according to the pre-fabricated circuit pattern. This results in a second region with a roughness of 0.02 μm-80 μm for the effective area of ​​the copper foil, and a side surface roughness of 0.1 μm-80 μm for the effective area of ​​the conductive layer. The uniform volume resistivity of the second region 2211 and the third region 23 is 3.2 × 10⁻⁶. -8 Ωm.

[0095] Step 2-2: This step is an alternative to or a preferred embodiment of Step 2-1. The conductive layer 2 is processed using a laser with a frequency of 177Hz and a circular cursor diameter of 10μm-100μm (which can be 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 97μm, 99μm, 100μm, etc.), preferably 50μm, at 100% power and a speed of 1000-20000nm / s (preferably 6700nm / s) from the copper foil. The functional surface intervention involves engraving and sintering the conductive layer 2 according to a preset circuit pattern. During this process, a spraying device located at the laser head position is activated to simultaneously spray alumina ceramic material onto the boundary area of ​​the effective region. The spraying area is controlled to extend 0.1μm-20mm (preferably 5mm) from the boundary of the effective region. This results in a roughness of 0.02μm-80μm in the 10μm-100μm region inward from the boundary of the functional surface of the conductive layer copper foil, and a surface roughness of 0.1μm-80μm on the side surface of the effective region of the conductive layer. The volume resistivity of these regions is 5.1×10⁻⁶. -8 Ωm.

[0096] Step 3: Perform laser engraving on the side surface and specific edge areas of the effective conductive layer (which can be the first area 2111 of the first metal layer aluminum foil and / or the second area 2211 of the second metal layer copper foil). The laser parameters selected are 50-500Hz, and the spot pattern can be circular, rectangular, etc. The spot diameter needs to be limited by the vertical distance from the effective area boundary line to the area of ​​the conductive adhesive introduced in the subsequent process on the functional surface of the conductive copper foil. This ensures that the formed concave structure does not exceed the point of action of the conductive adhesive closest to the ineffective area of ​​the conductive layer on the copper foil, thus forming a concave wavy structure on the side surface and specific edge areas. In a further preferred embodiment, a staggered concave wavy structure can be formed on two opposite side surfaces of adjacent effective areas.

[0097] Step 4: Provide an insulating substrate, and press the substrate 1 with the conductive layer 2 processed in the above steps to obtain the pressed product.

[0098] Step 5: Provide adhesive film 3 and laminate adhesive film 3 with the pressed product obtained in step 4.

[0099] It should be noted that steps 1-5 above are merely an example and do not constitute any limitation on the process, procedures and steps of the manufacturing method disclosed in this application.

[0100] In some independent embodiments within the scope of this application or based on the above embodiments, the manufacturing method disclosed in this application further includes the following steps:

[0101] Provide adhesive film 3 and place it on the second metal layer 22;

[0102] Composite substrate 1, conductive layer 2, and adhesive film 3.

[0103] In one example, the adhesive film 3 can be applied to the second metal layer 22 before the composite carrier 1 and conductive layer 2 in step S300. Accordingly, the conductive backplate is obtained by composite carrier 1, conductive layer 2 and adhesive film 3 in one step in step S300. This operation can simplify the composite process and improve manufacturing efficiency.

[0104] In another example, the composite carrier plate 1 and conductive layer 2 in step S300 can be completed first to form a semi-finished product. Then, the adhesive film 3 is placed on the second metal layer 22, and the adhesive film 3 is compounded with the semi-finished product to obtain a conductive backplate.

[0105] When the above technical solution is adopted, the carrier plate 1, the conductive layer 2 and the adhesive film 3 are combined into a whole. The second metal layer 22 is connected to the battery cell 4 through the adhesive film 3. The conductive layer 2 and the battery cell 4 are electrically connected by introducing conductive adhesive into the opening 31 provided on the adhesive film 3. That is, the introduction of the adhesive film 3 can not only realize the conductive connection between the second effective area on the second metal layer 22 and the corresponding conductive area on the battery cell 4 (which can be the PAD point on the battery cell), but also work together with the ineffective area 24 (i.e. the waste removal passage) of the conductive layer 2 to effectively realize the insulation between different conductive areas of the battery cell.

[0106] It should be noted that in the production process of conductive backsheets where production rhythm and process design are coordinated, those skilled in the art can reasonably adjust the operation sequence of some or all of the other production processes disclosed in this application, such as patterning process, roughness treatment process, volume resistivity treatment process, and setting concave corrugated body structure process, according to the reasonable design of production rhythm and process, merge processes, and use the same or similar technical means to complete the aforementioned conductive layer treatment process or process in the same process to reduce the unit time production cost and improve production efficiency. However, all of these are within the scope of protection of this application and do not exceed the inventive concept of this application.

[0107] The conductive backsheet and manufacturing method disclosed in this application, as a whole design, achieve synergistic effects in photovoltaic cell conversion efficiency, low unit manufacturing cost, high unit production efficiency, and high module reliability. In some optional implementations, based on the convenience, efficiency, and effectiveness of the subsequent stripping of ineffective areas (waste areas) of the conductive layer, this application also roughens specific edge regions of each effective area (or effective unit, effective area unit, or similar functional name) of the functional surface of the conductive metal layer. Furthermore, based on the electrical isolation requirements between adjacent conductive effective area units of the conductive backsheet layer, this application roughens the side surface (i.e., the third region) of each effective area of ​​the conductive layer to improve or ensure the electrical isolation performance between two adjacent effective areas, further enhancing the reliability of the conductive backsheet product and the reliability of modules using this conductive backsheet. In some implementations of this application, based on the high safety requirements of photovoltaic module products, this application also discloses methods to improve the volume resistivity of the effective area of ​​the conductive layer by processing the edge area and side surface area of ​​the conductive layer, and to further improve the electrical isolation performance of adjacent effective areas of the conductive layer by processing the surface of these areas with an inward corrugated body structure, thereby improving the electrical safety requirements of the conductive backsheet and improving the safety of photovoltaic modules using conductive backsheets.

[0108] Based on the conductive backsheet described in any of the above embodiments, this application also provides a photovoltaic module, mainly including a module frame, an encapsulation cover, solar cells, an encapsulation film, and the conductive backsheet described in any of the above embodiments, as well as a junction box. In some embodiments, the encapsulation cover is a transparent cover for light transmission. In this embodiment, the encapsulation cover, encapsulation film, solar cells, and conductive backsheet are stacked sequentially before the frame and junction box are added. This photovoltaic module has the same beneficial effects as the conductive backsheet in any of the above embodiments, and will not be described again here.

[0109] Photovoltaic modules with this conductive backsheet can be used for heterojunction photovoltaic modules, back-contact photovoltaic modules, and gridless photovoltaic modules.

[0110] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0111] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A conductive backplane, comprising a carrier plate and a patterned conductive layer, wherein, The conductive layer is a metal layer disposed on the carrier plate, and the surface roughness Ra of the functional surface of the conductive layer for electrical contact with the battery cell is 0.02μm to 0.3μm.

2. The conductive backplate according to claim 1, wherein, The conductive layer includes at least a first metal layer and a second metal layer stacked together, wherein the first metal layer is disposed on the carrier plate and the second metal layer is disposed on the first metal layer; The surface roughness Ra1 of the functional surface of the first metal layer is 0.3 μm to 0.5 μm; The surface roughness Ra2 of the functional surface of the second metal layer is 0.02μm to 0.3μm.

3. The conductive backplate according to claim 1, wherein, The patterned conductive layer includes an effective region and an ineffective region; the effective region includes a first effective region of a first metal layer and a second effective region of a second metal layer; the first effective region includes a first region of a functional surface of the first metal layer, and the second effective region includes a second region of a functional surface of the second metal layer. The roughness Ra3 of the first region is 0.3μm to 100μm; wherein the first region is a region that spreads from the boundary of the first effective region into the first effective region, and the spread distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive back plate on the functional surface of the first metal layer; Alternatively, the roughness Ra4 of the second region is 0.02μm to 80μm; wherein the second region is a region that spreads from the boundary of the second effective region into the second effective region, and the spread distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer.

4. The conductive backplate according to claim 3, wherein, The spread distance of the first region is 10μm to 100μm; Alternatively, the spread distance of the second region is 10μm to 100μm.

5. The conductive backplate according to any one of claims 2-4, wherein, The conductive layer includes a third region, the roughness of which is 0.1 μm to 80 μm.

6. The conductive backplate according to claim 2 or 3, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; The effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, and the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer. The first region is the region that extends from the boundary of the first effective region to the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is the region that extends from the boundary of the second effective region to the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; The volume resistivity of the first region and the third region is greater than the volume resistivity of the remaining regions of the first metal layer; Alternatively, the volume resistivity of the second region and the third region is greater than the volume resistivity of the remaining regions of the second metal layer; Alternatively, the volume resistivity of the first region, the second region, and the third region is greater than the volume resistivity of the remaining regions of the conductive layer.

7. The conductive backplate according to claim 6, wherein, The spread distance of the first region is 10μm to 100μm; or, the spread distance of the second region is 10μm to 100μm.

8. The conductive backplate according to claim 6, wherein, The volume resistivity of the first region and / or the second region, and the third region, is 3.15 × 10⁻⁶. -8 Ωm~5×10 -8 Ωm.

9. The conductive backplate according to claim 1, wherein, The conductive layer includes active units and inactive units. The edge-specific region of the active unit includes an upper surface, a side surface, and a lower surface. The edge-specific region is the area that extends from the boundary of the active unit into the active unit, and the extended area does not exceed the mapping area of ​​the reserved points of the conductive backplate on the conductive layer. At least one of the upper surface, the lower surface, and the side surface has a wave structure that is concave with the side surface as a reference plane; the wave crest of the wave structure does not exceed the mapping area of ​​the reserved point closest to the invalid unit on the conductive back plate on the conductive layer.

10. The conductive backplate according to claim 2 or 3, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; The effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, and the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer. The first region is the region that extends from the boundary of the first effective region to the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is the region that extends from the boundary of the second effective region to the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; At least one of the first region, the second region, and the third region has a wave structure that is concave with the third region as a reference plane; the wave crest of the wave structure does not exceed the mapping area of ​​the reserved point of the invalid region closest to the conductive layer on the conductive backplate.

11. The conductive backplate according to claim 10, wherein, The wave structure on the third region of the two adjacent effective regions is staggered.

12. The conductive backplate according to claim 4, 7, or 11, wherein, Ra1 and Ra2 are not equal; And / or, the material of the first metal layer is different from the material of the second metal layer.

13. The conductive backplate according to claim 12, wherein, The first metal layer is aluminum foil; the second metal layer is copper foil, and Ra2 is 0.05μm to 0.2μm.

14. The conductive backplate according to claim 4, 7, or 11, wherein, The thickness of the conductive layer is 30μm to 100μm; And / or, the tensile strength of the conductive layer is greater than or equal to 200 MPa; And / or, the resistivity of the conductive layer is less than or equal to 5 × 10⁻⁶. -8 Ωm.

15. The conductive backplate according to claim 14, wherein, The conductive backplate also includes an adhesive film disposed on the second metal layer.

16. A method for manufacturing a conductive backplane, wherein, include: Provide a carrier board; Provides a patterned conductive layer; The carrier plate and the conductive layer are combined, and the surface roughness Ra of the functional surface of the conductive layer for electrical contact with the battery cell is 0.02 μm to 0.3 μm.

17. The manufacturing method according to claim 16, wherein, The patterned conductive layer includes: A conductive layer is provided, which is composed of at least a first metal layer and a second metal layer stacked together; wherein the first metal layer is disposed on the carrier plate, the second metal layer is disposed on the first metal layer, the roughness Ra1 of the functional surface of the first metal layer is 0.3 μm to 0.5 μm, and the roughness Ra2 of the functional surface of the second metal layer is 0.02 μm to 0.3 μm.

18. The manufacturing method according to claim 17, wherein, The provision of a conductive layer consisting of at least a first metal layer and a second metal layer further includes patterning the conductive layer. The patterning process of the conductive layer includes: die-cutting the conductive layer according to a pre-made circuit pattern.

19. The manufacturing method according to claim 18, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; the effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer, the first region is a region that extends from the boundary of the first effective region toward the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is a region that extends from the boundary of the second effective region toward the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; The conductive layer comprising at least a first metal layer and a second metal layer further includes: The first region is roughened so that the roughness Ra3 of the first region is 0.3μm to 100μm; Alternatively, the second region can be roughened to a roughness Ra4 of 0.02 μm to 80 μm.

20. The manufacturing method according to any one of claims 17-19, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; the effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer, the first region is a region that extends from the boundary of the first effective region toward the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is a region that extends from the boundary of the second effective region toward the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; The conductive layer comprising at least a first metal layer and a second metal layer further includes: The third region is roughened to a roughness of 0.1 μm to 80 μm.

21. The manufacturing method according to any one of claims 17-19, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; the effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer, the first region is a region that extends from the boundary of the first effective region toward the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is a region that extends from the boundary of the second effective region toward the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; Before bonding the carrier plate and the conductive layer, the manufacturing method further includes: The volume resistivity of the first region and the third region is greater than the volume resistivity of the remaining regions of the first metal layer; Alternatively, the volume resistivity of the second and third regions is greater than the volume resistivity of the remaining regions of the second metal layer; Alternatively, the volume resistivity of the first region, the second region, and the third region may be greater than the volume resistivity of the remaining regions of the conductive layer.

22. The manufacturing method according to claim 21, wherein, Methods for treating volume resistivity include: The first region and / or the second region, and the third region are doped with group 5 or group 6 elements; wherein the domain spread distance of the first region is 10-100 μm; or, the domain spread distance of the second region is 10-100 μm; Alternatively, a laser with a frequency of 50-500Hz and a circular spot diameter of 10-100μm can be used to sinter the first region and / or the second region, and the invalid region.

23. The manufacturing method according to any one of claims 17-19, wherein, The conductive layer includes an effective region, an ineffective region, and a third region; the effective region includes a first effective region of the first metal layer and a second effective region of the second metal layer; the first effective region includes a first region of the functional surface of the first metal layer and the remaining region of the first metal layer, the second effective region includes a second region of the functional surface of the second metal layer and the remaining region of the second metal layer, the first region is a region that extends from the boundary of the first effective region toward the first effective region, and the extension distance of the first region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the first metal layer; the second region is a region that extends from the boundary of the second effective region toward the second effective region, and the extension distance of the second region does not exceed the mapping area of ​​the reserved point of the conductive backplate on the functional surface of the second metal layer. The third region is the side surface of the effective region of the conductive layer; Before bonding the carrier plate and the conductive layer, the manufacturing method further includes: At least one of the first region, the second region, and the third region is processed such that the at least one region has a concave wave structure with the third region as the reference plane, and the wave crest of the wave structure does not exceed the mapping area of ​​the reserved point closest to the invalid region on the conductive backplate on the conductive layer.

24. The manufacturing method according to any one of claims 17-19, wherein, Also includes: A film is provided and disposed on the second metal layer; The carrier plate, the conductive layer, and the adhesive film are combined.

25. The manufacturing method according to claim 20, wherein, The roughness treatment method includes at least one of laser treatment, mechanical treatment, and chemical treatment.

26. A photovoltaic module, wherein, The conductive backplate includes the conductive backplate as described in any one of claims 1-15, or the conductive backplate manufactured by the method of manufacturing the conductive backplate as described in any one of claims 16-25.

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