CN116207172A - Photovoltaic module and preparation method thereof - Google Patents

Abstract

The embodiment of the present application relates to the field of photovoltaic technology, and provides a photovoltaic module and its preparation method. The photovoltaic module includes: a plurality of battery sheets, each of which has a plurality of grid lines on the surface of the battery sheet; a connecting part, the connecting part It is located on the surface of the battery sheet, and the connection parts are respectively connected to the adjacent battery sheets, and the part of the connection part located on the grid line is in contact with the adjacent part of the grid line; the encapsulation layer, the The encapsulation layer covers the surface of the battery sheet and the surface of the connecting part, and the encapsulation layer at least includes a first encapsulation layer, a second encapsulation layer and a third encapsulation layer arranged in sequence along a direction away from the battery sheet , wherein the fluidity of the third encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the first encapsulation layer decrease in sequence. The embodiments of the present application are at least beneficial to improving the efficiency and yield of photovoltaic modules.

Description

Photovoltaic module and its preparation method

technical field

The embodiments of the present application relate to the field of photovoltaic technologies, and in particular to a photovoltaic module and a manufacturing method thereof.

Background technique

With the development of photovoltaic technology, in the manufacture of photovoltaic cells or photovoltaic modules, it has become a major concern to improve the efficiency of photovoltaic cells and improve the yield of photovoltaic cells while saving manufacturing costs.

As an important part of solar cells, grid wires are used to collect and export electrons generated by the photovoltaic effect. Ribbons are used to connect cells in photovoltaic modules. The quality of welding, the selection of ribbon material and grid wire material, the welding method of ribbon and grid wire, and the adhesive film above the ribbon all have a great impact on the photoelectric conversion efficiency of the cell, the efficiency of the photovoltaic module, the yield of the photovoltaic module, and the photovoltaic The life of the module has a certain impact. At present, the arrangement of grid lines, soldering strips and adhesive films in photovoltaic modules needs to be improved.

Contents of the invention

Embodiments of the present application provide a photovoltaic module and a manufacturing method thereof, which are at least beneficial to improving the efficiency and yield of the photovoltaic module.

According to some embodiments of the present application, the embodiments of the present application provide a photovoltaic module on the one hand, including: a plurality of battery sheets, each of which has a plurality of grid lines on the surface of the battery sheet; a connecting part, the connecting part is located on the surface of the battery sheet, and The connection parts are respectively connected to the adjacent cells, and the part of the connection part on the grid line is in contact with the adjacent part of the grid line; the packaging layer, the packaging layer covers the surface of the battery chip and the surface of the connection part, and the packaging layer at least includes The first encapsulation layer, the second encapsulation layer and the third encapsulation layer are sequentially arranged in the direction away from the battery sheet, wherein the fluidity of the third encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the first encapsulation layer decrease in turn. Small.

In some embodiments, the ratio of the ML value of the first encapsulation layer to the ML value of the second encapsulation layer is 1.1˜3.

In some embodiments, the ratio of the ML value of the second encapsulation layer to the ML value of the third encapsulation layer is 1.1˜4.

In some embodiments, the ML value of the first encapsulation layer is 0.4 dN·m˜0.85 dN·m, and/or the ML value of the second encapsulation layer is 0.3 dN·m˜0.4 dN·m.

In some embodiments, the ML value of the third encapsulation layer is 0.1 dN·m˜0.3 dN·m.

In some embodiments, it further includes: glue points, the glue points are located between some of the battery sheets and the connection components, and the glue points are located on the surface of the battery sheets other than the grid lines.

In some embodiments, the first encapsulation layer, the second encapsulation layer and the third encapsulation layer are integrally formed.

In some embodiments, the ratio of the thickness of the first encapsulation layer to the maximum thickness of the connection part is 0.4˜1 along the direction from the cell sheet to the encapsulation layer.

In some embodiments, the ratio of the thickness of the first encapsulation layer to the thickness of the second encapsulation layer is 1-4 along the direction from the cell sheet to the encapsulation layer.

In some embodiments, the ratio of the thickness of the second encapsulation layer to the thickness of the third encapsulation layer is 0.2-0.7 along the direction of the battery sheet pointing to the encapsulation layer.

In some embodiments, the material of the first encapsulation layer, the material of the second encapsulation layer and the material of the third encapsulation layer are the same.

According to some embodiments of the present application, on the other hand, the embodiment of the present application also provides a method for preparing a photovoltaic module, including: providing a plurality of battery sheets, each of which has a plurality of grid lines on the surface of the battery sheet; The connection part is arranged; the encapsulation layer is arranged on the surface of the cell sheet, and the encapsulation layer is located on the side of the connection part away from the cell sheet, and the encapsulation layer includes a first encapsulation layer, a second encapsulation layer and a third Encapsulation layer: Laminate the cells, connecting parts and encapsulation layer at a preset temperature, so that the part of the connection part located above the grid lines is in contact with the adjacent part of the grid lines, and the cells and the encapsulation layer are in contact with each other. fixed; wherein, the fluidity of the third encapsulation layer at a preset temperature, the fluidity of the second encapsulation layer at a preset temperature, and the fluidity of the first encapsulation layer at a preset temperature decrease in sequence.

In some embodiments, arranging the connection part further includes: forming a glue point, the glue point is located between a part of the battery sheet and the connection part, and the glue point is located on the surface of the battery sheet other than the grid lines.

The technical solution provided by the embodiment of the present application has at least the following advantages: the grid line can be a fine grid on the surface of the battery sheet, and the connecting part can be a solder strip arranged on the surface of the battery sheet instead of the main grid and used to connect adjacent battery sheets. Parts replace the main grid, on the one hand, it avoids setting a thicker main grid, which is beneficial to reduce the cost of photovoltaic modules; on the other hand, it avoids the excessive shielding of the surface of the cell by the main grid, which is conducive to improving the photoelectric conversion of the cell Efficiency, which in turn helps to improve the efficiency of photovoltaic modules. The encapsulation layer is used to cover the surface of the battery sheet and the connecting parts, and is used to protect the battery sheet. The encapsulation layer at least includes a first encapsulation layer, a second encapsulation layer and a third encapsulation layer arranged in sequence along a direction away from the battery sheet, and The fluidity of the third encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the first encapsulation layer decrease sequentially, wherein the fluidity of the first encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the third encapsulation layer The fluidity is the fluidity at the lamination temperature, that is, the photovoltaic module is the photovoltaic module in the lamination process. The lamination process refers to the process of laying the connecting parts on the surface of the battery sheet, covering the connecting parts and the surface of the battery sheet exposed by the connecting parts with the encapsulation layer, and then laminating the battery sheet, the connecting parts and the encapsulating layer. The process has a certain lamination temperature, and at the lamination temperature, the connection part and the grid wire located below the connection part form an alloy, thereby forming a contact connection. Normally, when the encapsulation layer is in the scorch stage at the lamination temperature, the encapsulation layer is in a fluid state. In order to prevent the encapsulation layer in the scorch stage from flowing into the connection part and the grid line before the connection part and the grid line are alloyed between the connecting parts and the grid lines, and the first encapsulation layer adjacent to the connecting parts and the battery sheet is set to a state of less fluidity, which can prevent the first encapsulating layer from flowing between the connecting parts and the grid lines , thereby avoiding poor contact between the connecting part and the grid line, which is conducive to improving the efficiency and yield of the photovoltaic module. In addition, using the first encapsulation layer to isolate the second encapsulation layer and the third encapsulation layer with relatively high fluidity, and using the second encapsulation layer as a bridge between the first encapsulation layer and the third encapsulation layer is beneficial to increase the The adhesive strength between the first encapsulation layer and the third encapsulation layer, the third encapsulation layer with the highest fluidity is beneficial to ensure that the encapsulation layer and the cover plate have strong adhesive strength, which in turn is beneficial to improve the life of the photovoltaic module.

Description of drawings

One or more embodiments are exemplified by the figures in the accompanying drawings, these exemplifications are not construed as limiting the embodiments, unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limitation; for To more clearly illustrate the technical solutions in the embodiment of the present application or the conventional technology, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application , for those skilled in the art, other drawings can also be obtained according to these drawings on the premise of not paying creative work.

Fig. 1 is a schematic cross-sectional structure diagram of a photovoltaic module provided by an embodiment of the present application;

Fig. 2 is a structural schematic diagram of grid lines and connecting parts on the surface of a cell provided by an embodiment of the present application;

Fig. 3 is a schematic diagram of a vulcanization curve provided by an embodiment of the present application;

Fig. 4 is a partial cross-sectional structural schematic diagram of a photovoltaic module before lamination provided by an embodiment of the present application;

Fig. 5 is a schematic structural diagram corresponding to the step of providing cells in a method for preparing a photovoltaic module provided by an embodiment of the present application;

Fig. 6 is a structural schematic diagram corresponding to the step of forming glue points in a method for preparing a photovoltaic module provided by an embodiment of the present application;

Fig. 7 is a structural schematic diagram corresponding to the step of fixing the connecting parts with glue points in a method for preparing a photovoltaic module provided by an embodiment of the present application;

Fig. 8 is a structural schematic diagram corresponding to the step of setting an encapsulation layer in a method for preparing a photovoltaic module provided by an embodiment of the present application;

FIG. 9 is a schematic structural diagram of a photovoltaic module after lamination in a method for manufacturing a photovoltaic module according to an embodiment of the present application.

Detailed ways

It can be seen from the background art that the arrangement of grid lines, solder strips and adhesive films in photovoltaic modules needs to be improved.

The analysis found that when sunlight enters the battery from the surface of the cell, the grid lines on the surface of the cell will block the cell, and the light energy irradiated on the metal electrode will not be converted into electrical energy. Therefore, from the perspective of blocking the light , it is generally desired that the grid lines be made as thin as possible; while the grid lines are used to conduct current, from the perspective of resistivity, the thinner the grid lines, the smaller the conductive cross-sectional area and the greater the resistance loss. Therefore, the core of grid line design is to strike a balance between shading and conductivity. Usually, the main component of the paste for making the grid lines is the expensive precious metal silver, and in the process of connecting the cells into modules, it is necessary to connect the main grid of one cell to the main grid of the adjacent cell through the welding ribbon. Gate welding, therefore, generally needs to form a thicker main grid to ensure the connection between the ribbon and the main grid. To sum up, the material cost is high and the thicker busbar results in higher component manufacturing cost. Therefore, if the main grid is replaced by a ribbon with a lower material cost, and more and thinner ribbons are directly connected to the fine grid of the battery, it will not only help reduce the preparation cost of grid lines and ribbons, but also help improve solar energy. The photoelectric conversion efficiency of the battery.

However, the connection between the conventional ribbon and the grid wire needs to be welded to alloy the ribbon and the grid wire. Usually, the conventional solder ribbon includes a solder layer, and the melting point of the solder layer in the solder ribbon is 183°C. In the actual soldering process, the soldering temperature is 20°C higher than the melting point of the solder. Therefore, a higher soldering temperature is required to alloy the ribbon and the grid line, and the higher soldering temperature will cause the cell to warp during the soldering process. The deformation is large, which in turn leads to a high risk of hidden cracks and a high rate of fragmentation after welding, resulting in an increase in the repair rate of components and a decrease in yield. Therefore, in order to reduce welding damage, low temperature soldering tape can be used. Low temperature ribbons are usually used to form the connections to the gatelines during the lamination process. However, during the lamination process, due to the increase in temperature, the adhesive film on the top of the ribbon will change into a fluid state, and the fluid adhesive film will easily flow to the ribbon and grid before the alloy is formed between the ribbon and the grid line. Between the wires, resulting in poor contact between the ribbon and the grid wires, which in turn affects the efficiency and yield of photovoltaic modules.

In order to solve the above problems, the present application provides a photovoltaic module and its preparation method. In the photovoltaic module, the grid line can be a fine grid on the surface of the battery sheet, and the connecting part can be arranged on the surface of the battery sheet instead of the main grid and used to connect phases. The connecting parts are used to replace the main grid for the soldering strips adjacent to the cells. On the one hand, it avoids setting a thicker main grid, which is beneficial to reduce the cost of photovoltaic modules; , which is conducive to improving the photoelectric conversion efficiency of the battery sheet, which in turn is beneficial to improving the efficiency of the photovoltaic module. The encapsulation layer is used to cover the surface of the battery sheet and the connecting parts, and is used to protect the battery sheet. The encapsulation layer at least includes a first encapsulation layer, a second encapsulation layer and a third encapsulation layer arranged in sequence along a direction away from the battery sheet, and The fluidity of the third encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the first encapsulation layer decrease sequentially, wherein the fluidity of the first encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the third encapsulation layer The fluidity is the fluidity at the lamination temperature, that is, the photovoltaic module is the photovoltaic module in the lamination process. Setting the first encapsulation layer adjacent to the connection part and the battery sheet to a state of low fluidity can prevent the first encapsulation layer from flowing between the connection part and the grid line, thereby avoiding poor contact between the connection part and the grid line, which is beneficial to Improve the efficiency and yield of photovoltaic modules. In addition, using the first encapsulation layer to isolate the second encapsulation layer and the third encapsulation layer with relatively high fluidity, and using the second encapsulation layer as a bridge between the first encapsulation layer and the third encapsulation layer is beneficial to increase The bonding strength between the first encapsulation layer and the third encapsulation layer is large, and the third encapsulation layer with the highest fluidity is conducive to ensuring a strong bonding strength between the encapsulation layer and the cover plate, thereby improving the life of the photovoltaic module.

Various embodiments of the present application will be described in detail below in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in each embodiment of the application, many technical details are provided for readers to better understand the application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in this application can also be realized.

Fig. 1 is a schematic cross-sectional structure diagram of a photovoltaic module provided by an embodiment of the present application; Fig. 2 is a schematic structural diagram of grid lines and connecting parts on the surface of a battery sheet provided by an embodiment of the present application.

Referring to Fig. 1 and Fig. 2, the photovoltaic module includes: a plurality of battery slices 100, each of which has a plurality of grid lines 110 on the surface of the battery slice 100; connecting parts 120, the connecting parts 120 are located on the surface of the battery slices 100, and the connecting parts 120 are respectively To connect adjacent battery sheets 100 , part of the connection member 120 located on the grid line 110 is in contact with the adjacent part of the grid line 110 .

The battery sheet 100 is used to absorb photons in the incident light and generate electron-hole pairs. The electron-hole pairs are separated by the built-in electric field in the battery sheet 100 to generate a potential at both ends of the PN junction, thereby converting light energy into electrical energy. In some embodiments, one surface of the cell sheet 100 serves as a light-receiving surface for absorbing incident light. In other embodiments, both surfaces of the cell sheet 100 are used as light-receiving surfaces for absorbing incident light. In some embodiments, the solar cell 100 may be a crystalline silicon solar cell, for example, a monocrystalline silicon solar cell or a polycrystalline silicon solar cell. It can be understood that, in some embodiments, the number of battery slices 100 in a photovoltaic module can be one or more, and when the number of battery slices 100 is multiple, it can be divided into whole or multiple pieces (for example, 1/ 2 equal slices, 1/3 equal slices, 1/4 equal slices and other multiple slices) are electrically connected to form multiple battery strings, and the multiple battery strings are electrically connected in series and/or in parallel.

The battery sheet 100 may include but not limited to PERC battery (Passivated Emitter and Rear Cell, passivated emitter and back battery), PERT battery (Passivated Emitter and Rear Totally-diffused cell, passivated emitter back surface fully diffused cell), TOPCon battery (Tunnel Oxide PassivatedContact, tunnel oxide passivated contact battery), HIT/HJT battery (Heterojunction Technology, heterojunction battery).

The cell sheet 100 may include a substrate, and the substrate may be a silicon substrate. In some embodiments, the battery sheet 100 has a front side 101 and a back side 102 opposite to each other. Both the front side 101 and the back side 102 may be printed with metal paste to form grid lines 110 with specific patterns.

In some embodiments, a plurality of battery sheets 100 in the photovoltaic module are arranged at intervals, and the plurality of battery sheets 100 are arranged in parallel, and the connecting member 120 connects the two opposite surfaces of the adjacent two battery sheets 100 respectively. An electrical connection between the two battery sheets 100 is formed.

In some embodiments, the connecting part 120 may be a welding strip, and the cross-sectional shape of the connecting part 120 may be any one of a circle, a rectangle, a trapezoid or a triangle along a direction perpendicular to the extending direction of the connecting part 120 .

In some embodiments, the grid lines 110 may be thin grids on the surface of the battery sheet 100, and the thin grids are used to collect and export electrons generated by the photovoltaic effect. The connection part 120 may be a ribbon arranged on the surface of the battery sheet 100 instead of the main grid and used to connect the adjacent battery sheet 100. Using the connection part 120 instead of the main grid avoids setting a thicker main grid, which is beneficial to reduce the photovoltaic power consumption. On the other hand, it avoids too much shielding of the surface of the battery sheet 100 by the busbar, which is beneficial to improve the photoelectric conversion efficiency of the battery sheet 100, and further helps to improve the efficiency of the photovoltaic module.

In some embodiments, referring to FIG. 2, the grid line 110 may be a fine grid on the surface of the battery sheet 100, and the connecting member 120 may be a soldering strip arranged on the surface of the battery sheet 100 instead of the main grid and used to connect adjacent battery sheets 100, A plurality of grid lines 110 extend along the first direction X on the surface of the battery sheet and are arranged at intervals along the second direction Y, and a plurality of connecting members 120 extend along the second direction Y on the surface of the battery sheet and are arranged at intervals along the first direction X cloth, wherein the first direction X intersects the second direction Y.

In some embodiments, the grid lines 110 may also be main grids and fine grids. The thin grid is used to guide the current, and the main grid is used to collect the current on the thin grid for confluence. The connection part 120 is a solder strip connected to the main grid.

It should be noted that the connecting part 120 in the embodiment of the present application is a low-temperature soldering tape, which forms a connection with the grid line 110 during the lamination process, avoiding the excessively high soldering temperature caused by the use of a high-temperature soldering tape, and further This avoids damage to the cell sheet 100 caused by excessive welding temperature, which is beneficial to reducing the repair rate of the photovoltaic module and improving the yield of the photovoltaic module.

In some embodiments, the connecting part 120 is a tin-coated metal solder strip, and the melting temperature of the tin layer is not higher than 150° C., generally 130° C.-150° C., which is beneficial to adapt to the lamination temperature of the photovoltaic module.

Referring to FIG. 1 , the photovoltaic module further includes an encapsulation layer 130, the encapsulation layer 130 covers the surface of the battery sheet 100 and the surface of the connecting member 120, and the encapsulation layer 130 includes at least the first encapsulation layer 131, The second encapsulation layer 132 and the third encapsulation layer 133 , wherein the fluidity of the third encapsulation layer 133 , the fluidity of the second encapsulation layer 132 and the fluidity of the first encapsulation layer 131 decrease in sequence. The encapsulation layer 130 is used for encapsulation and protection of the battery sheet, and the encapsulation layer may be an adhesive film.

It should be noted that the fluidity of the first encapsulation layer 131, the fluidity of the second encapsulation layer 132, and the fluidity of the third encapsulation layer 133 are all fluidity at the lamination temperature, that is, the photovoltaic module is in the lamination process. The photovoltaic module, the lamination process refers to laying the connection part 120 on the surface of the battery sheet 100, and covering the encapsulation layer 130 on the connection part 120 and the surface of the battery sheet 100 exposed by the connection part 120, the battery sheet 100, the connection part 120 As well as the lamination process of the encapsulation layer 130 , the lamination process has a certain lamination temperature, and at the lamination temperature, the connection part 120 forms an alloy with the gate line 110 located below the connection part 120 , and then forms a contact connection. At the lamination temperature, when the encapsulation layer is in the scorch stage, the encapsulation layer is in a state of fluidity, and the first encapsulation layer 131 adjacent to the connecting member 120 and the battery sheet 100 is set to a state of less fluidity, which avoids the first The encapsulation layer 131 flows between the connection part 120 and the grid line 110 , resulting in poor contact between the connection part 120 and the grid line 110 , which is beneficial to improve the efficiency and yield of the photovoltaic module. In addition, the first encapsulation layer 131 is used to isolate the second encapsulation layer 132 and the third encapsulation layer 133 with relatively high fluidity, and the second encapsulation layer 132 is used as a barrier between the first encapsulation layer 131 and the third encapsulation layer 133 The bridge is conducive to increasing the adhesive strength between the first encapsulation layer 131 and the third encapsulation layer 133, and the third encapsulation layer 133 with the highest fluidity is conducive to ensuring that the encapsulation layer 130 and the cover plate have a strong adhesive strength, thereby having It is beneficial to improve the life of photovoltaic modules.

The fluidity of the first encapsulation layer 131 can be expressed by the ML value of the first encapsulation layer 131, the fluidity of the second encapsulation layer 132 can be expressed by the ML value of the second encapsulation layer 132, and the fluidity of the third encapsulation layer 133 It can be represented by the ML value of the third encapsulation layer 133, the ML value is the lowest torque in the vulcanization curve of the adhesive film, the lower the ML value, the greater the fluidity of the adhesive film before the crosslinking reaction occurs during the lamination process; the ML value The higher the value, the less fluid the film will be before the crosslinking reaction occurs during lamination.

The vulcanization curve is used to characterize the vulcanization performance of the film. The vulcanization performance is the performance of the vulcanization process of the film. During the vulcanization process, the film will undergo a vulcanization reaction. The vulcanization reaction (cross-linking reaction) refers to: the molecular chain of the film is chemically or Under the action of physical factors, chemical cross-linking occurs and becomes a spatial network structure. The linear macromolecules of the unvulcanized rubber film are curled and in a state of free movement. When an external force is applied, the linear macromolecules are prone to displacement, that is, there is a large plastic flow. In the vulcanized rubber film, the soft linear macromolecules Type macromolecules become a spatial network structure through cross-linking, so the relative motion of linear macromolecules is limited to a certain extent. Under the action of external force, large displacements are not easy to occur, resulting in higher stress and strength, physical mechanical properties and chemical properties. Improved by vulcanization.

Usually, the vulcanization tester can be used to measure the change of the vulcanization performance of the film during the vulcanization process. Under constant, small amplitude and low frequency sinusoidal shear deformation, the shear stress is measured by the load cell of the vulcanization tester, and the shear stress is expressed in units of torque, and the recorded shear stress-time curve is vulcanization curve.

FIG. 3 is a schematic diagram of a vulcanization curve provided by an embodiment of the present application. Referring to Figure 3, the vulcanization process of the film can be divided into four stages: scorching stage, heat vulcanization stage, flat vulcanization stage and overvulcanization stage. The scorch stage is equivalent to the induction period in the vulcanization reaction. During this period, the crosslinking has not yet started, the film has fluidity, and the film sample produces crosslinkable free radicals. The thermal vulcanization stage is the vulcanization reaction (crosslinking reaction) stage, the film molecules gradually form a network structure, and the elasticity and strength of the film rise sharply. During the flat vulcanization stage, the film has reached an appropriate degree of crosslinking. During this period, the physical and mechanical properties of the film have reached or approached the optimum point, or achieved the best comprehensive balance. In the oversulfurization stage, the cross-linking bonds in the film are rearranged, and the cross-linking bonds and molecular chains in the film undergo thermal cracking reactions, and the performance of the film decreases.

Referring to FIG. 3 , the minimum torque ML represents the minimum shear stress value before the cross-linking reaction of the rubber film starts, that is, the maximum value of the fluidity of the rubber film before the cross-linking reaction starts during the vulcanization process.

In some embodiments, the encapsulation layer may also include sequentially arranging the first encapsulation layer, the second encapsulation layer, the third encapsulation layer and the fourth encapsulation layer along the direction away from the battery sheet, wherein the fluidity of the fourth encapsulation layer, The fluidity of the third encapsulation layer, the fluidity of the second encapsulation layer and the fluidity of the first encapsulation layer decrease sequentially. The embodiment of the present application does not specifically limit the number of stacked layers with different fluidities in the encapsulation layer, as long as the fluidity of multiple stacked layers on the surface of the cell sheet increases sequentially along the direction away from the cell sheet.

In some embodiments, the encapsulation layer 130 is disposed on the front side 101 and the back side 102 of the battery sheet 100, and covers the connection part 120 on the surface of the battery sheet 100, for encapsulating the battery sheet 100, and can connect the battery sheet 100 and the cover plate (not shown) for bonding.

In some embodiments, the first encapsulation layer 131 before lamination is a pre-crosslinked adhesive film, the second encapsulation layer 132 before lamination is a pre-crosslinked adhesive film, and the third encapsulation layer 133 before lamination is a non-pre-crosslinked adhesive film. The difference between cross-linked film, pre-cross-linked film and non-pre-cross-linked film is: before lamination, whether there is a cross-linking reaction between the internal molecules of the film material. The cross-linking reaction refers to the relatively stable molecules (body-shaped molecules) in which two or more molecules (usually linear molecules) are bonded and cross-linked to form a network structure. Usually, during the lamination process, after a certain lamination time at a certain lamination temperature, the adhesive film presents a state of greater fluidity (scorch stage), and the crosslinking agent in the adhesive film decomposes Generate free radicals. As time goes by, free radicals trigger the combination of long-chain molecules in the film, making the film, battery sheet and cover bonded and fixed together. Before lamination, some molecules inside the pre-crosslinked film have undergone a cross-linking reaction. Therefore, the fluidity of the pre-crosslinked film in the scorch stage is smaller than that of the non-pre-crosslinked film in the scorch stage. The fluidity of the crosslinked film in the scorch stage depends on the proportion of molecules that have undergone crosslinking reaction in the pre-crosslinked film before lamination.

In some embodiments, the first encapsulation layer 131 may be a POE (copolymer of ethylene octene) adhesive film. In some embodiments, the second encapsulation layer 132 may be a POE (copolymer of ethylene octene) adhesive film. In some embodiments, the third encapsulation layer 133 may be a POE (copolymer of ethylene octene) adhesive film. POE film is composed of saturated fatty chains, has good UV aging resistance, excellent heat resistance and low temperature resistance, and POE film has a wide temperature range, good light transmittance, excellent electrical insulation performance, and high cost performance And easy processing and so on.

In some embodiments, the first packaging layer 131 may be an EVA film. In some embodiments, the second packaging layer 132 may be an EVA film. In some embodiments, the third packaging layer 133 may be an EVA film. EVA film is a relatively common film. The main component of EVA film is ethylene-vinyl acetate copolymer (EVA). EVA film can also include a small amount of cross-linking agent, auxiliary cross-linking agent, anti-aging agent and other Functional aids.

In some embodiments, the material of the first encapsulation layer 131 , the material of the second encapsulation layer 132 and the material of the third encapsulation layer 133 are the same. Using the same material as the first encapsulation layer 131, the second encapsulation layer 132, and the third encapsulation layer 133 is beneficial to ensure that the molecules of the first encapsulation layer 131 and the molecules of the second encapsulation layer 132 have a higher bonding strength, and ensure that The molecules of the second encapsulation layer 132 and the molecules of the third encapsulation layer 133 have higher bonding strength, which is beneficial to improve the bonding strength between the laminated first encapsulation layer 131 and the second encapsulation layer 132, and has It is beneficial to improve the adhesive strength between the laminated second encapsulation layer 132 and the third encapsulation layer 133 .

In some embodiments, the first encapsulation layer 131 , the second encapsulation layer 132 and the third encapsulation layer 133 are integrally formed. Compared with laminating the split-type first encapsulation layer 131, second encapsulation layer 132, and third encapsulation layer 133, the integrally formed first encapsulation layer 131, second encapsulation layer 132, and third encapsulation layer 133 are directly used As the encapsulation layer 130, it is beneficial to ensure that the first encapsulation layer 131 and the second encapsulation layer 132 have a higher bonding and fixing strength, and it is beneficial to ensure that the second encapsulation layer 132 and the third encapsulation layer 133 have a higher bonding strength. Excellent bonding and fixing strength, which in turn helps to improve the structural stability of photovoltaic modules.

In some embodiments, the materials of the first encapsulation layer 131, the second encapsulation layer 132, and the third encapsulation layer 133 are all the same, and the first encapsulation layer 131, the second encapsulation layer 132, and the third encapsulation layer 133 are integrated. molding structure. In some embodiments, the method of forming the encapsulation layer 130 may be: obtaining an initial encapsulation layer, the initial encapsulation layer may be a non-pre-crosslinked adhesive film, and the initial encapsulation layer includes a stacked first part, a second part, and a third part. The side of the first part away from the third part pre-crosslinks the initial encapsulation layer, so that part of the molecules in the first part of the initial encapsulation layer undergo a crosslinking reaction, and part of the molecules in the second part of the initial encapsulation layer A cross-linking reaction occurs, and the proportion of molecules undergoing a cross-linking reaction in the initial encapsulation layer of the first part is higher than the proportion of molecules undergoing a cross-linking reaction in the initial encapsulation layer of the second part, so as to form a pre-cross-linked compound with increasing fluidity. Linked first encapsulation layer 131 and pre-crosslinked second encapsulation layer 132, the initial encapsulation layer of the third part is still a non-pre-crosslinked adhesive film, and the initial encapsulation layer of the third part is used as the third encapsulation layer with the greatest fluidity Layer 133 , as such, facilitates the ease of obtaining encapsulation layer 130 . Wherein, the pre-crosslinking treatment may be crosslinking treatment such as electron beam irradiation or ultraviolet light irradiation.

In some embodiments, the method of forming the encapsulation layer 130 may be: obtain a split initial first encapsulation layer, an initial second encapsulation layer, and an initial third encapsulation layer, an initial first encapsulation layer, an initial second encapsulation layer, and an initial The third encapsulation layer is a non-pre-crosslinked adhesive film, and the initial first encapsulation layer and the initial second encapsulation layer are pre-crosslinked to different degrees, so that some molecules in the initial first encapsulation layer undergo a crosslinking reaction, and causing a cross-linking reaction to occur on some of the molecules in the initial second encapsulation layer, and the proportion of molecules undergoing a cross-linking reaction in the first part of the initial encapsulation layer is higher than the proportion of molecules undergoing a cross-linking reaction in the second part of the initial encapsulation layer , to form a pre-crosslinked first encapsulation layer 131 and a pre-crosslinked second encapsulation layer 132 with higher fluidity in turn, and the initial third encapsulation layer as a non-pre-crosslinked third encapsulation layer 133 with greater fluidity . The split first encapsulation layer 131 , the second encapsulation layer 132 and the third encapsulation layer 133 are fixed together to form the encapsulation layer 130 . Wherein, the pre-crosslinking treatment may be crosslinking treatment such as electron beam irradiation or ultraviolet light irradiation.

In some embodiments, the ratio of the ML value of the first encapsulation layer 131 to the ML value of the second encapsulation layer is 1.1˜3. If the ML value of the first encapsulation layer 131 is defined as ML1, and the ML value of the second encapsulation layer 132 is defined as ML2, the ratio of ML1 to ML2 is 1.1-3, for example, 1.5, 2, 2.5, 2.6 or 2.7. If the ratio of ML1 to ML2 is too small, the first encapsulation layer 131 will be in a state of high fluidity, which will cause the first encapsulation layer 131 in the scorching stage to flow between the gate line 110 and the connecting member 120 where no alloy is formed. , resulting in poor contact between the gate line 110 and the connecting member 120 . If the ratio of ML1 to ML2 is too large, the fluidity of the first encapsulation layer 131 will be too small, that is, before lamination, the proportion of molecules that have undergone cross-linking reaction in the first encapsulation layer 131 will be too large, resulting in the after lamination. In the photovoltaic module, the bonding and fixing ability of the first encapsulation layer 131 is poor, so that there is a risk of separation between the battery sheet 100 and the first encapsulation layer 131 in the photovoltaic module. Therefore, setting the ratio of ML1 to ML2 to be 1.1-3 is not only beneficial to avoid poor contact between the gate line 110 and the connecting member 120 , but also beneficial to ensure that the first encapsulation layer 131 has a higher adhesive strength.

In some embodiments, the ratio of the ML value of the second encapsulation layer 132 to the ML value of the third encapsulation layer 133 is 1.1˜4. If the ML value of the second encapsulation layer 132 is defined as ML2, and the ML value of the third encapsulation layer 133 is defined as ML3, the ratio of ML2 to ML3 is 1.1-4, such as 1.5, 2, 2.5, 2.6 or 3.5. If the ratio of ML2 to ML3 is too small, the fluidity of the second encapsulation layer 132 is too close to the fluidity of the third encapsulation layer 133, so that the second encapsulation layer 132 cannot serve as a good connection between the first encapsulation layer 131 and the third encapsulation layer 133. The connection bridges, that is, reduce the bonding strength between the first encapsulation layer 131 and the second encapsulation layer 132 . If the ratio of ML2 to ML3 is too large, the fluidity of the second encapsulation layer 132 is too close to the fluidity of the first encapsulation layer 131, so that the second encapsulation layer 132 cannot serve as a good connection between the first encapsulation layer 131 and the third encapsulation layer 133. The connection bridges, that is, reduce the bonding strength between the third encapsulation layer 133 and the second encapsulation layer 132 . Therefore, setting the ratio of ML2 to ML3 to be 1.1-4 is beneficial to ensure a higher adhesive strength between the first encapsulation layer 131 and the second encapsulation layer 132, and to ensure that the second encapsulation layer 132 and the third encapsulation layer The encapsulation layers 133 have relatively high adhesive strength.

In some embodiments, the ML value of the first encapsulation layer 131 is 0.4 dN·m˜0.85 dN·m. For example, it may be 0.42dN·m, 0.45dN·m, 0.5dN·m, 0.75dN·m, or 0.8dN·m. If the ML value of the first encapsulation layer 131 is too small, the fluidity of the first encapsulation layer 131 will be too large, which will cause the first encapsulation layer 131 in the scorching stage to flow between the gate line 110 and the connecting member 120 where no alloy has been formed. This results in poor contact between the gate line 110 and the connecting member 120 . If the ML value of the first encapsulation layer 131 is too large, the fluidity of the first encapsulation layer 131 is too small. In the final photovoltaic module, the adhesion and fixing ability of the first encapsulation layer 131 is too poor. Therefore, setting the fluidity ML value of the first encapsulation layer 131 to 0.4dN·m-0.85dN·m can ensure that the fluidity of the first encapsulation layer 131 is within a reasonable range, which is not only beneficial to avoid grid lines caused by The poor contact between 110 and the connection part 120 is also beneficial to ensure that the first encapsulation layer 131 has a higher adhesive strength.

If the ML value of the first encapsulation layer is defined as ML1, the ML value of the second encapsulation layer is ML2, and the ML value of the third encapsulation layer is ML3, refer to the ML value of the first encapsulation layer and the second encapsulation layer in the following table The influence of the ML value of and the ML value of the third encapsulation layer on the connection state of the laminated gate line and the connecting part.

The data sources in the above table can be as follows: sampling the connection points of the connection parts and the grid lines located in the same area on the battery sheets of multiple comparative examples, and sampling the connection parts and grid lines located in the same area on the battery sheets of multiple embodiments The connection point of each cell is sampled, the total number of samples on each cell can be 50, and the number of samples that connect the grid line and the connection part to form a contact connection on the cell sheet is counted, so as to obtain the formation of the connection part and the grid line of each comparative example. The percentage of the number of samples that are contacted and connected to the total number of samples, and the percentage of the number of samples that form a contact connection between the connecting component and the gate line of each embodiment to the total number of samples.

Referring to the above table, when the value of the ML value (ML2) of the second encapsulation layer is constant, the value of the ML value (ML3) of the third encapsulation layer is constant, and the greater the ML value (ML1) of the first encapsulation layer, the connection between the component and the grid The higher the percentage of the number of samples in which the line forms a contact connection to the total number of samples, the lower the ratio of poor contact between the connection part and the grid line (refer to Comparative Example 1, Example 1, Example 2 and Example 4, or refer to Comparative Example 3. Embodiment 5, Embodiment 6 and Embodiment 8). When the ML value (ML1) of the first encapsulation layer is greater than or equal to 0.4dN·m, the number of samples in which the connecting parts and grid lines form a contact connection accounts for more than 95% of the total number of samples, that is, the photovoltaic module is a qualified product (reference implementation Examples 1-8). When the ML value (ML1) of the first encapsulation layer is less than 0.4dN·m, the number of samples in which the connecting parts and grid lines form a contact connection accounts for less than 95% of the total number of samples, and the photovoltaic module is a substandard product (refer to Comparative Example 1 ~3). Therefore, setting the ML value of the first encapsulation layer to be greater than 0.4 dN·m is beneficial to improving the yield and efficiency of the photovoltaic module.

Continuing to refer to the above table, when the ML value (ML1) of the first encapsulation layer is greater than or equal to 0.4dN·m, the change of the ML value (ML2) of the second encapsulation layer can no longer affect the connection state of the gate line and the connecting parts (Refer to Embodiment 2 and Embodiment 3, or Embodiment 6 and Embodiment 7), that is, the first encapsulation layer with poor flow realizes an effective isolation barrier for the second encapsulation layer. When the ML value (ML1) of the first encapsulation layer is greater than or equal to 0.4dN·m, the change of the ML value (ML3) of the third encapsulation layer cannot affect the connection state of the gate line and the connecting member (refer to embodiment 1 and Example 5, or Example 2 and Example 6).

In some embodiments, the ML value of the second encapsulation layer 132 is 0.3dN·m˜0.4dN·m, for example, it may be 0.32dN·m, 0.35dN·m, 0.36dN·m, 0.38dN·m or 0.39 dN·m etc. If the ML value of the second encapsulation layer 132 is too small, the fluidity of the second encapsulation layer 132 is too close to the fluidity of the third encapsulation layer 133, so that the second encapsulation layer 132 cannot serve as the first encapsulation layer 131 and the third encapsulation layer 133. There is a good connection bridge between them, that is, the bonding strength between the first encapsulation layer 131 and the second encapsulation layer 132 is reduced. If the ML of the second encapsulation layer 132 is too large, the fluidity of the second encapsulation layer 132 is too close to the fluidity of the first encapsulation layer 131, so that the second encapsulation layer 132 cannot be used as a link between the first encapsulation layer 131 and the third encapsulation layer 133. There is a good connection bridge between them, that is, the bonding strength between the third encapsulation layer 133 and the second encapsulation layer 132 is reduced. Therefore, setting the ML value of the second encapsulation layer 132 to 0.3dN·m-0.4dN·m is beneficial to ensure a high adhesive strength between the first encapsulation layer 131 and the second encapsulation layer 132, and to ensure that The bonding strength between the second encapsulation layer 132 and the third encapsulation layer 133 is relatively high.

In some embodiments, the ML value of the third encapsulation layer 133 is 0.1dN·m˜0.3dN·m, for example, it may be 0.12dN·m, 0.15dN·m, 0.2dN·m, 0.25dN·m or 0.3 dN·m etc. If the fluidity of the third encapsulation layer is too small, the bonding and fixing ability of the third encapsulation layer in the laminated photovoltaic module will be too poor. Therefore, setting the ML value of the third encapsulation layer to 0.1dN·m˜0.3dN·m is beneficial to ensure that the third encapsulation layer has a higher adhesive strength.

FIG. 4 is a partial cross-sectional structural schematic diagram of a photovoltaic module before lamination provided by an embodiment of the present application.

In some embodiments, as shown in FIG. 4 , the ratio of the thickness L2 of the first encapsulation layer 131 to the maximum thickness L1 of the connecting member 120 is along the direction from the cell sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 0.4 to 1. For example, it may be 0.4, 0.5, 0.6, 0.7, or 0.9. If the ratio of the thickness L2 of the first encapsulation layer 131 to the maximum thickness L1 of the connecting member 120 is too large, the thickness L2 of the first encapsulation layer 131 will be too large, and the first encapsulation layer 131 with an excessive thickness will affect the Effect of light absorption. If the ratio of the thickness L2 of the first encapsulation layer 131 to the maximum thickness L1 of the connecting member 120 is too small, the thickness L2 of the first encapsulation layer 131 will be too small, and the scorching stage of the encapsulation layer during the lamination process may cause the second The first encapsulation layer 131 cannot well block the second encapsulation layer 132 , so that the second encapsulation layer 132 flows between the gate line 110 and the connection part 120 . Therefore, setting the ratio of the thickness L2 of the first encapsulation layer 131 to the maximum thickness L1 of the connecting member 120 to 0.4 to 1, on the one hand, helps to prevent the overly thick first encapsulation layer 131 from blocking the light, that is, to ensure that the battery The sheet 100 has a high utilization rate of light; on the other hand, it is beneficial to ensure that the first encapsulation layer 131 can effectively block the second encapsulation layer 132, which in turn is beneficial to ensure that a good connection between the grid line 110 and the connecting member 120 is formed. touch.

In some embodiments, referring to FIG. 4 , along the direction from the cell sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 , the thickness L2 of the first encapsulation layer 131 and the thickness L3 of the second encapsulation layer 132 The ratio is 1-4. For example, it can be 1, 2, 2.5, or 3, etc. When the thickness L2 of the first encapsulation layer 131 is fixed, if the ratio of the thickness L2 of the first encapsulation layer 131 to the thickness L3 of the second encapsulation layer 132 is too large, the thickness L3 of the second encapsulation layer 132 will be too small. Therefore, the second encapsulation layer 132 with too small thickness cannot serve as a good connection bridge between the first encapsulation layer 131 and the third encapsulation layer 133 . Moreover, the thickness of the second encapsulation layer 132 that is too small will cause the overall thickness of the encapsulation layer 130 to be too small, which may cause water vapor to enter the battery sheet 100 and cause the battery sheet 100 to fail. When the thickness L2 of the first encapsulation layer 131 is fixed, if the ratio of the thickness L2 of the first encapsulation layer 131 to the thickness L3 of the second encapsulation layer 132 is too small, the thickness L3 of the second encapsulation layer 132 will be too large. , the second encapsulation layer 132 with too large thickness will affect the light absorption of the battery sheet 100 . In addition, the second encapsulation layer 132 with too large thickness will increase the manufacturing cost of the photovoltaic module. Therefore, setting the ratio of the thickness L2 of the first encapsulation layer 131 to the thickness L3 of the second encapsulation layer 132 to 1 to 4 is not only beneficial to ensure that the second encapsulation layer 132 performs good encapsulation and protection on the battery sheet 100, but also facilitates Enhancing the light utilization rate of the solar cell 100 and making the amount of materials for preparing the second encapsulation layer 132 reasonable are beneficial to realize the weight reduction of the photovoltaic module and reduce the manufacturing cost of the photovoltaic module.

In some embodiments, referring to FIG. 4 , along the direction from the cell sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 , the thickness L3 of the second encapsulation layer 132 is the same as the thickness L4 of the third encapsulation layer 133 The ratio is 0.2 to 0.7. For example, it may be 0.3, 0.4, 0.5, 0.6, or 0.7. When the thickness L3 of the second encapsulation layer 132 is fixed, if the ratio of the thickness L3 of the second encapsulation layer 132 to the thickness L4 of the third encapsulation layer 133 is too large, the thickness L4 of the third encapsulation layer 133 will be too small. Since the laminated third encapsulation layer 133 has high adhesive strength, the third encapsulation layer 133 with too small thickness cannot provide good encapsulation and protection for the battery sheet 100 , which may cause the cover plate to be separated from the battery sheet 100 . Moreover, the thickness of the third encapsulation layer 133 that is too small will cause the overall thickness of the encapsulation layer 130 to be too small, which may cause water vapor to enter the battery sheet 100 and cause the battery sheet 100 to fail. When the thickness L3 of the second encapsulation layer 132 is fixed, if the ratio of the thickness L3 of the second encapsulation layer 132 to the thickness L4 of the third encapsulation layer 133 is too small, the thickness L4 of the third encapsulation layer 133 will be too large. , the third encapsulation layer 133 with too large thickness will affect the light absorption of the cell sheet 100 . In addition, the third encapsulation layer 133 with too large thickness will increase the manufacturing cost of the photovoltaic module. Therefore, setting the ratio of the thickness L3 of the second encapsulation layer 132 to the thickness L4 of the third encapsulation layer 133 to be 0.2-0.7 is not only beneficial to ensure that the third encapsulation layer 133 provides good encapsulation and protection for the battery sheet 100, but also facilitates Enhancing the light utilization rate of the battery sheet 100 and making the amount of materials for preparing the third encapsulation layer 133 reasonable are beneficial to realize the weight reduction of the photovoltaic module and reduce the manufacturing cost of the photovoltaic module.

It should be noted that the maximum thickness L1 of the connection part 120 involved in the embodiment of the present application is the thickness of the connection part 120 before lamination, the thickness L2 of the first encapsulation layer 131 is the thickness of the first encapsulation layer 131 before lamination, and the first encapsulation layer 131 is the thickness before lamination. The thickness L3 of the second encapsulation layer 132 is the thickness of the second encapsulation layer 132 before lamination, and the thickness L4 of the third encapsulation layer 133 is the thickness of the third encapsulation layer 133 before lamination.

In some embodiments, referring to FIG. 4 , along the direction from the cell sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 , the maximum thickness L1 of the connecting member 120 is 200 μm˜260 μm, for example, 200 μm , 210μm, 230μm, 235μm or 250μm. If the maximum thickness L1 of the connection part 120 is too large, the connection part 120 will use too much material, which will lead to an increase in the cost of the photovoltaic module. If the maximum thickness L1 of the connecting part 120 is too small, the conductive cross-sectional area of the connecting part 120 will be too small, which will lead to too large resistance loss. Therefore, setting the maximum thickness L1 of the connection part 120 to 200 μm to 260 μm is beneficial to ensure that the size of the connection part 120 is within a reasonable range, helps to avoid increasing the cost of the photovoltaic module, and is conducive to reducing the resistance loss, which in turn is conducive to improving the photovoltaic module. component efficiency.

In some embodiments, referring to FIG. 1 and FIG. 4 , along the direction from the cell sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 , the thickness L2 of the first encapsulation layer 131 is 110 μm to 200 μm, for example Can be: 120 μm, 130 μm, 150 μm, 165 μm or 180 μm. The first encapsulation layer 131 with too large thickness will affect the light absorption of the cell sheet 100 . The thickness L2 of the first encapsulation layer 131 is too small. During the scorching stage of the encapsulation layer in the lamination process, the first encapsulation layer 131 may not be able to well block the second encapsulation layer 132 with higher fluidity, making the second encapsulation layer 132 The encapsulation layer 132 flows between the gate line 110 and the connection part 120 . Therefore, setting the thickness L2 of the first encapsulation layer 131 to 110 μm to 200 μm, on the one hand, helps to prevent the overly thick first encapsulation layer 131 from blocking the light, that is, it is beneficial to ensure that the battery sheet 100 has a higher utilization rate of light. ; On the other hand, it is beneficial to ensure that the first encapsulation layer 131 can effectively block the second encapsulation layer 132 , which in turn is beneficial to ensure good contact between the gate lines 110 and the connecting member 120 .

In some embodiments, referring to FIG. 1 and FIG. 4 , along the direction from the battery sheet 100 to the encapsulation layer 130 , that is, along the Z direction shown in FIG. 4 , the thickness L2 of the second encapsulation layer 132 is 50 μm to 100 μm, for example Can be: 60 μm, 70 μm, 80 μm or 90 μm. The second encapsulation layer 132 with too small thickness cannot serve as a good connection bridge between the first encapsulation layer 131 and the third encapsulation layer 133 . Moreover, the thickness of the second encapsulation layer 132 that is too small will cause the overall thickness of the encapsulation layer 130 to be too small, which may cause water vapor to enter the battery sheet 100 and cause the battery sheet 100 to fail. An overly thick second encapsulation layer 132 will affect the light absorption of the battery sheet 100 . In addition, the second encapsulation layer 132 with too large thickness will increase the manufacturing cost of the photovoltaic module. Therefore, setting the thickness L2 of the second encapsulation layer 132 to 50 μm to 100 μm is not only beneficial to ensure that the second encapsulation layer 132 provides good encapsulation and protection for the battery sheet 100, but also helps to enhance the utilization rate of the battery sheet 100 to light, and Making the amount of materials used for preparing the second encapsulation layer 132 reasonable is beneficial to realizing the weight reduction of the photovoltaic module and reducing the manufacturing cost of the photovoltaic module.

In some embodiments, referring to FIG. 1 and FIG. 4 , along the Z direction, the thickness L4 of the third encapsulation layer 133 is 140 μm˜260 μm, for example, 150 μm, 165 μm, 170 μm, 200 μm or 250 μm. A third encapsulation layer with too small thickness cannot provide good encapsulation and protection for the battery sheet 100 , which may cause the cover plate to be separated from the battery sheet 100 . Moreover, the thickness of the third encapsulation layer 133 that is too small will cause the overall thickness of the encapsulation layer 130 to be too small, which may cause water vapor to enter the battery sheet 100 and cause the battery sheet 100 to fail. The third encapsulation layer 133 with too large thickness will affect the light absorption of the cell sheet 100 . In addition, the third encapsulation layer 133 with too large thickness will increase the manufacturing cost of the photovoltaic module. Therefore, setting the thickness L4 of the third encapsulation layer 133 to 140 μm to 260 μm is not only beneficial to ensure that the third encapsulation layer 133 provides good encapsulation and protection for the battery sheet 100, but also helps to enhance the utilization rate of the battery sheet 100 for light, and Making the amount of materials used for preparing the third encapsulation layer 133 reasonable is not only beneficial to realizing the weight reduction of the photovoltaic module, but also beneficial to reducing the manufacturing cost of the photovoltaic module.

In some embodiments, referring to FIG. 1 and FIG. 2 , the photovoltaic module further includes: a glue point 140 located between some of the battery sheets 100 and the connection member 120 , and the glue point 140 is located on the battery sheet 100 outside the grid line 110 s surface. The glue point 140 is used to fix the connection part 120 before lamination, so as to prevent the connection part 120 from moving on the surface of the cell sheet 100 .

In some embodiments, referring to FIG. 1 , the photovoltaic module further includes: a cover plate 150, which is located on the surface of the encapsulation layer 130 away from the battery sheet 100, and the cover plate 150 can be a glass cover plate or a plastic cover plate for protection. Battery string cover.

In the photovoltaic module provided by the above embodiments, the encapsulation layer 130 at least includes the first encapsulation layer 131 , the second encapsulation layer 132 and the third encapsulation layer 133 arranged in sequence along the direction away from the battery sheet 100 , and the flow of the third encapsulation layer 133 The fluidity of the second encapsulation layer 132 and the fluidity of the first encapsulation layer 131 decrease in order, wherein the fluidity of the first encapsulation layer 131, the fluidity of the second encapsulation layer 132 and the fluidity of the third encapsulation layer 133 Both properties are fluidity at the lamination temperature, that is, the photovoltaic module is a photovoltaic module in the lamination process, and at the lamination temperature, the first encapsulation layer 131 adjacent to the connecting member 120 and the battery sheet 100 is set to have less fluidity In this state, the first encapsulation layer 131 can be prevented from flowing between the connection part 120 and the grid line 110, thereby avoiding poor contact between the connection part 120 and the grid line 110, which is beneficial to improving the efficiency and yield of the photovoltaic module. In addition, the first encapsulation layer 131 is used to isolate the second encapsulation layer 132 and the third encapsulation layer 133 with relatively high fluidity, and the second encapsulation layer 132 is used as a barrier between the first encapsulation layer 131 and the third encapsulation layer 133 The bridge is conducive to increasing the adhesive strength between the first encapsulation layer 131 and the third encapsulation layer 133, and the third encapsulation layer 133 with the highest fluidity is conducive to ensuring that the encapsulation layer 130 and the cover plate have a strong adhesive strength, thereby having It is beneficial to improve the life of photovoltaic modules.

According to some embodiments of the present application, on the other hand, the embodiments of the present application also provide a method for preparing a photovoltaic module. The method for preparing a photovoltaic module can be used to form the photovoltaic module involved in the above-mentioned embodiments. The preparation method of the photovoltaic module will be described. It should be noted that for the parts that are the same as or corresponding to the foregoing embodiments, reference may be made to the detailed descriptions of the foregoing embodiments, and details will not be repeated below.

Fig. 5 is a schematic structural diagram corresponding to the step of providing cells in a method for preparing a photovoltaic module provided by an embodiment of the present application; Fig. 6 is a schematic diagram of forming glue dots in a method for preparing a photovoltaic module provided by an embodiment of the application Schematic diagram of the structure corresponding to the steps; FIG. 7 is a schematic diagram of the structure corresponding to the step of fixing the connecting parts with glue points in a method for preparing a photovoltaic module provided by an embodiment of the present application; FIG. 8 is a schematic diagram of a structure provided by an embodiment of the present application. A schematic structural diagram corresponding to the step of setting an encapsulation layer in a method for preparing a photovoltaic module; FIG. 9 is a schematic structural diagram corresponding to a photovoltaic module after lamination treatment in a method for preparing a photovoltaic module provided by an embodiment of the present application. It should be noted that the number of battery slices is omitted in FIGS. 5 to 9 , and only one battery slice is used as an example for illustration.

Referring to FIG. 5 , the method for manufacturing a photovoltaic module includes: providing a plurality of battery sheets 100 , each of which has a plurality of grid lines 110 on its surface. In some embodiments, the grid lines 110 may be formed by screen printing and sintering processes.

Referring to FIG. 6 to FIG. 7 , a connection member 120 is provided on the surface of the battery sheet 100 .

In some embodiments, arranging the connection part 120 further includes: forming glue points 140 . Referring to FIG. 6, uncured glue points 140 can be formed on the surface of the battery sheet 100 other than the grid lines 110; referring to FIG. Between the sheet 100 and the connection part 120, after the connection part 120 is laid, the glue point 140 can be cured by ultraviolet light irradiation or other low-temperature treatment, and the connection part 120 can be fixed by the glue point 140 to prevent the connection part 120 from moving.

Referring to FIG. 8 , an encapsulation layer 130 is provided on the surface of the battery sheet 100 , and the encapsulation layer 130 is located on the side of the connecting member 120 away from the battery sheet 100 . , the second encapsulation layer 132 and the third encapsulation layer 133 .

Continuing to refer to FIG. 8 , in some embodiments, while the encapsulation layer 130 is provided, a cover plate 150 is also provided on the surface of the encapsulation layer 130 away from the battery.

Referring to FIG. 9 , the battery sheet 100, the connection member 120 and the encapsulation layer 130 are laminated at a preset temperature, so that the part of the connection member 120 located above the grid line 110 is in contact with the adjacent part of the grid line 110, and The cell sheet 100 is fixed to the encapsulation layer 130; wherein, the fluidity of the third encapsulation layer 133 at a preset temperature, the fluidity of the second encapsulation layer 132 at a preset temperature, and the fluidity of the first encapsulation layer 131 at a preset temperature Mobility decreases sequentially.

In some embodiments, the lamination process also secures the encapsulation layer 130 to the cover plate 150 .

Setting the first encapsulation layer 131 adjacent to the connecting member 120 and the cell sheet 100 to a state of less fluidity can prevent the first encapsulating layer 131 from flowing between the connecting member 120 and the grid line 110 , thereby preventing the connecting member 120 from Poor contact of the grid lines 110 is beneficial to improve the efficiency and yield of the photovoltaic module. In addition, the first encapsulation layer 131 is used to isolate the second encapsulation layer 132 and the third encapsulation layer 133 with relatively high fluidity, and the second encapsulation layer 132 is used as a barrier between the first encapsulation layer 131 and the third encapsulation layer 133 The bridge is conducive to increasing the adhesive strength between the first encapsulation layer 131 and the third encapsulation layer 133, and the third encapsulation layer 133 with the highest fluidity is conducive to ensuring that the encapsulation layer 130 and the cover plate have a strong adhesive strength, thereby having It is beneficial to improve the life of photovoltaic modules.

It should be noted that the preset temperature may be higher than the temperature at which the connecting member 120 and the grid wire 110 form an alloy, and lower than the temperature at which the encapsulation layer 130 undergoes a crosslinking reaction, so that the connecting member 120 and the grid wire 110 are at the preset temperature. An alloy is formed, and after the connecting member 120 and the gate line 110 are alloyed, the encapsulation layer 130 undergoes a cross-linking reaction.

In the manufacturing method of the photovoltaic module provided in the above-mentioned embodiment, the first encapsulation layer 131 adjacent to the connecting member 120 and the cell sheet 100 is set in a state of low fluidity, which prevents the first encapsulating layer 131 from flowing to the connecting member 120 and the grid. Between the wires 110 , poor contact between the connection part 120 and the grid wire 110 is caused, which is beneficial to form a photovoltaic module with higher yield and efficiency. Moreover, the first encapsulation layer 131 is used to isolate the second encapsulation layer 132 and the third encapsulation layer 133 with relatively high fluidity, and the second encapsulation layer 132 is used as a gap between the first encapsulation layer 131 and the third encapsulation layer 133 The bridge is conducive to increasing the adhesive strength between the first encapsulation layer 131 and the third encapsulation layer 133, and the third encapsulation layer 133 with the highest fluidity is conducive to ensuring that the encapsulation layer 130 and the cover plate have a strong adhesive strength, thereby It is beneficial to form a photovoltaic module with high structural stability.

It should be noted that in the drawings provided in this embodiment, the structure of the photovoltaic module and the shape of the photovoltaic module do not constitute a limitation of the structure and shape of the photovoltaic module in this embodiment. It can be understood that the structure of the photovoltaic module The structure and the shape of the photovoltaic module can be designed and modified according to the photovoltaic module that needs to be matched.

Those of ordinary skill in the art can understand that the above-mentioned implementation modes are specific examples for realizing the present application, and in practical applications, various changes can be made to it in form and details without departing from the spirit and spirit of the present application. scope. Any person skilled in the art can make respective alterations and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be determined by the scope defined in the claims.

Claims (13)

1. A photovoltaic module, comprising:

a plurality of battery pieces, wherein the surface of each battery piece is provided with a plurality of grid lines;

the connecting parts are positioned on the surfaces of the battery pieces and are respectively connected with adjacent battery pieces, and the parts positioned on the grid lines are in contact connection with the adjacent parts of the grid lines;

The packaging layer covers the surface of the battery piece and the surface of the connecting component, and the packaging layer at least comprises a first packaging layer, a second packaging layer and a third packaging layer which are sequentially distributed along the direction far away from the battery piece, wherein the fluidity of the third packaging layer, the fluidity of the second packaging layer and the fluidity of the first packaging layer are sequentially reduced.

2. The photovoltaic module of claim 1, wherein the ratio of the ML value of the first encapsulant layer to the ML value of the second encapsulant layer is 1.1-3.

3. The photovoltaic module according to claim 1 or 2, wherein the ratio of the ML value of the second encapsulation layer to the ML value of the third encapsulation layer is 1.1 to 4.

4. The photovoltaic module according to claim 1 or 2, wherein the ML value of the first encapsulation layer is 0.4 dN-m to 0.85 dN-m and/or the ML value of the second encapsulation layer is 0.3 dN-m to 0.4 dN-m.

5. The photovoltaic module of claim 1, wherein the ML value of the third encapsulation layer is 0.1 dN-m to 0.3 dN-m.

6. The photovoltaic module of claim 1, further comprising: and the glue point is positioned between part of the battery piece and the connecting part, and is positioned on the surface of the battery piece outside the grid line.

7. The photovoltaic assembly of claim 1, wherein the first, second, and third encapsulation layers are an integrally formed structure.

8. The photovoltaic module according to claim 1, wherein a ratio of a thickness of the first encapsulation layer to a maximum thickness of the connection member in a direction in which the battery sheet is directed toward the encapsulation layer is 0.4 to 1.

9. The photovoltaic module of claim 1, wherein a ratio of a thickness of the first encapsulant layer to a thickness of the second encapsulant layer in a direction in which the cell sheet is directed toward the encapsulant layer is 1 to 4.

10. The photovoltaic module according to claim 1 or 9, wherein a ratio of a thickness of the second encapsulation layer to a thickness of the third encapsulation layer in a direction in which the cell sheet is directed toward the encapsulation layer is 0.2 to 0.7.

11. The photovoltaic module of claim 1, wherein the material of the first encapsulant layer, the material of the second encapsulant layer, and the material of the third encapsulant layer are the same.

12. A method of manufacturing a photovoltaic module, comprising:

providing a plurality of battery pieces, wherein the surface of each battery piece is provided with a plurality of grid lines;

A connecting component is arranged on the surface of the battery piece;

arranging a packaging layer on the surface of the battery piece, wherein the packaging layer is positioned on one side of the connecting part far away from the battery piece, and the packaging layer comprises a first packaging layer, a second packaging layer and a third packaging layer which are sequentially arranged along the direction far away from the battery piece;

laminating the battery piece, the connecting component and the packaging layer at a preset temperature to enable the connecting component positioned above the grid line to be in contact connection with the adjacent grid line and enable the battery piece to be fixed with the packaging layer;

the mobility of the third packaging layer at the preset temperature, the mobility of the second packaging layer at the preset temperature and the mobility of the first packaging layer at the preset temperature are sequentially reduced.

13. The method of manufacturing a photovoltaic module according to claim 12, wherein providing the connection member further comprises: and forming glue points, wherein the glue points are positioned between part of the battery pieces and the connecting parts, and the glue points are positioned on the surfaces of the battery pieces outside the grid lines.

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