CN116741860A

CN116741860A - Photovoltaic module and preparation method thereof

Info

Publication number: CN116741860A
Application number: CN202310712816.6A
Authority: CN
Inventors: 刘立勤; 王路闯; 陶武松; 陈振东
Original assignee: Jinko Solar Co Ltd; Jinko Solar Haining Co Ltd
Current assignee: Jinko Solar Co Ltd; Jinko Solar Haining Co Ltd
Priority date: 2023-06-15
Filing date: 2023-06-15
Publication date: 2023-09-12

Abstract

The embodiment of the application relates to the field of photovoltaics, and provides a photovoltaic module and a preparation method thereof, wherein the photovoltaic module comprises: a plurality of battery strings, each battery string including a plurality of battery plates; the welding strip is used for electrically connecting every two adjacent battery pieces; wherein, the battery piece and the welding strip are provided with an overlapping area; the first packaging layer and the second packaging layer cover two sides of the battery string respectively; at least one of the first encapsulation layer or the second encapsulation layer comprises: the device comprises a main body part and a plurality of pre-crosslinking parts penetrating the main body part in the thickness direction of the main body part and distributed at intervals, wherein each pre-crosslinking part is opposite to each battery piece, and each pre-crosslinking part is also positioned in an overlapping area; wherein the degree of crosslinking of the pre-crosslinked portion is greater than the degree of crosslinking of the main body portion; the cover plate is positioned on one side of the first packaging layer away from the battery string and one side of the second packaging layer away from the battery string.

Description

Photovoltaic module and preparation method thereof

Technical Field

The embodiment of the application relates to the field of photovoltaics, in particular to a photovoltaic module and a preparation method thereof.

Background

Solar cells are devices that directly convert light energy into electrical energy through a photoelectric effect or a photochemical effect. The single solar cell cannot be directly used for power generation. Several single batteries must be connected in series and parallel by welding strips and tightly packaged into a module for use. Solar cell modules (also called solar panels) are the core part of and the most important part of a solar power generation system. The solar cell module is used for converting solar energy into electric energy, or sending the electric energy to a storage battery for storage, or pushing a load to work.

The battery piece is very fragile, and the upper and lower surfaces of the battery assembly are generally required to be provided with adhesive films and cover plates so as to assemble the battery assembly into the photovoltaic assembly, wherein the adhesive films and the cover plates are used for protecting the battery piece. The cover plate is generally made of photovoltaic glass, the photovoltaic glass cannot be directly attached to the battery piece, and the adhesive film is required to be adhered in the middle. The connection between the battery cells typically requires a solder strip for collecting current, and conventional solder strips require alloying between the solder strip and the fine grid by welding during soldering. However, the melting point of the solder in the solder strip is generally high, and in the actual soldering process, the soldering temperature is 20 ℃ higher than the melting point of the solder. The battery piece is large in buckling deformation in the welding process, so that the hidden cracking risk after welding is large, and the breaking rate is high.

In the above background, in order to improve the welding quality, the low temperature solder strip and no main grid technology are generated. However, there are many factors that affect the yield of the photovoltaic module, such as the effect of welding between the solder strip and the fine grid, the yield of welding, and bubbles in the adhesive film.

Disclosure of Invention

The embodiment of the application provides a photovoltaic module and a preparation method thereof, which are at least beneficial to providing the yield of the photovoltaic module.

According to some embodiments of the present application, an aspect of an embodiment of the present application provides a photovoltaic module, including: a plurality of battery strings, each of the battery strings including a plurality of battery cells; the welding strip is used for electrically connecting every two adjacent battery pieces; wherein, the battery piece and the welding strip are provided with an overlapping area; the first packaging layer and the second packaging layer cover two sides of the battery string respectively; at least one of the first encapsulation layer or the second encapsulation layer comprises: the device comprises a main body part and a plurality of pre-crosslinking parts penetrating the main body part in the thickness direction of the main body part and arranged at intervals, wherein each pre-crosslinking part is opposite to each battery piece, and each pre-crosslinking part is also positioned in the overlapping area; wherein the degree of crosslinking of the pre-crosslinked portion is greater than the degree of crosslinking of the main body portion; and the cover plate is positioned on one side of the first packaging layer far away from the battery string and one side of the second packaging layer far away from the battery string.

In some embodiments, a first interval is arranged between adjacent battery strings, and a second interval is arranged between every two battery pieces; the main body portion covers the first and second spaces.

In some embodiments, the first encapsulation layer includes the body portion and the pre-crosslinked portion; and the ratio of the total area of the plurality of pre-crosslinking parts to the total area of the first packaging layer is less than or equal to 80 percent.

In some embodiments, the degree of crosslinking of the pre-crosslinked portion is less than or equal to 50%.

In some embodiments, the first encapsulation layer or the second encapsulation layer further comprises: at least one layer of adhesive film, the at least one layer of adhesive film is positioned on one side of the main body part and the pre-crosslinking part away from the battery string, and the crosslinking degree of each adhesive film is smaller than that of the pre-crosslinking part; the material of the adhesive film is different from the material of the main body part.

In some embodiments, the at least one adhesive film includes a first adhesive film and a second adhesive film, the first adhesive film is located between the main body portion and the second adhesive film, and a crosslinking degree of the first adhesive film is greater than or equal to a crosslinking degree of the second adhesive film.

In some embodiments, the body portion and the pre-crosslinked portion are of unitary construction.

In some embodiments, each of the pre-crosslinked regions is located in at least one of the overlap regions; alternatively, each of the pre-crosslinking regions is located in at least two adjacent overlap regions and a battery cell region between the two adjacent overlap regions.

In some embodiments, for the same cell, the ratio of the total area of the pre-cross-links to the area of the cell is S, S satisfying: s is more than or equal to 10% and less than or equal to 1.

According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a method for manufacturing a photovoltaic module, including: providing a plurality of battery pieces and welding strips; the welding strip is electrically connected with every two adjacent battery pieces to form a battery string, and the welding strip and the battery pieces are provided with overlapping areas; providing a first packaging layer and a second packaging layer, wherein the first packaging layer and the second packaging layer respectively cover two sides of the battery string; at least one of the first packaging layer or the second packaging layer comprises a main body part and a plurality of pre-crosslinking parts penetrating through the main body part along the thickness direction of the main body part and arranged at intervals, each pre-crosslinking part is opposite to each battery piece, and each pre-crosslinking part is also positioned in the overlapping area; wherein the degree of crosslinking of the pre-crosslinked portion is greater than the degree of crosslinking of the main body portion; a cover plate is provided, and covers one side of the first packaging layer far away from the battery string and one side of the second packaging layer far away from the battery string.

In some embodiments, providing the first encapsulation layer or the second encapsulation layer comprises: providing an initial packaging layer; pre-treating the initial packaging layer of the partial area, wherein the pre-treatment is used for increasing the crosslinking degree of the initial packaging layer of the partial area; the initial packaging layer after pretreatment is used as a pre-crosslinking part, the initial packaging layer without pretreatment is used as a main body part, and the pre-crosslinking part and the main body part form a first packaging layer or a second packaging layer.

In some embodiments, providing an initial encapsulation layer includes: providing a first initial film and a second initial film; typesetting the first initial film and the second initial film; calendering the first initial film and the second initial film to form an initial packaging layer; wherein the first initial film after pretreatment is used as a pre-crosslinking part, and the second initial film without pretreatment is used as a main body part.

In some embodiments, providing an initial encapsulation layer and pre-processing the initial encapsulation layer includes: providing a third initial film and a fourth initial film, wherein the third initial film is internally provided with an initiator; calendering the third initial film and the fourth initial film to form an initial packaging layer; wherein the fourth initial film is positioned on one side of the third initial film; preprocessing the initial packaging layer of a partial area; the initial packaging layer of the partial area containing the initiator is used as a pre-crosslinking part after being pretreated, the initial packaging layer of the partial area containing the initiator is used as a main body part without being pretreated, and the initial packaging layer without the initiator is used as a glue film; the pre-crosslinking part, the main body part and the adhesive film form a first packaging layer or a second packaging layer.

The technical scheme provided by the embodiment of the application has at least the following advantages:

in the photovoltaic module provided by the embodiment of the application, at least one of the first packaging layer or the second packaging layer comprises: the photovoltaic module comprises a main body part and a plurality of pre-crosslinking parts which penetrate the main body part in the thickness direction of the main body part and are distributed at intervals, wherein each pre-crosslinking part is used for being opposite to a battery piece, and each pre-crosslinking part is further located in an overlapping area, so that the degree of crosslinking of the pre-crosslinking parts is high, the fluidity is poor, a flowing packaging layer can be prevented from pushing a welding strip, the deviation between the welding strip and a thin grid line is caused, and the yield of the photovoltaic module is affected.

In addition, the pre-crosslinking part is used for being opposite to the battery piece, namely, the main body part is positioned in an area except the battery piece, such as a gap between the battery strings and a gap between the battery pieces, so that the gap between the battery pieces and the gap between the battery strings are filled, firstly, bubbles on the surface of the battery piece can be discharged through the gap, so that series of problems caused by glue shortage are avoided, secondly, the main body part with better fluidity is positioned in the gap between the battery pieces and the pre-crosslinking part, compared with the gap between the battery pieces, the main body part has better fluidity, so that the strength is lower, the damage to the battery pieces and the welding strips is smaller, and the damage rate of the battery pieces is reduced. The main part is located the gap between battery cluster and the battery cluster, because the gap between the battery cluster is great, thereby the encapsulation layer that fills can reduce the quantity of empty glue and improve photovoltaic module's intensity.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings required for the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

Fig. 1 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present application;

fig. 2 is a schematic structural diagram of a battery string in a photovoltaic module according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of a packaging layer in a photovoltaic module according to an embodiment of the present application;

fig. 4 is a schematic view of a first structure of a package layer and a battery string in a photovoltaic module according to an embodiment of the present application;

fig. 5 is a schematic view of a second structure of a packaging layer and a battery string in a photovoltaic module according to an embodiment of the present application;

Fig. 6 is a schematic structural diagram of a packaging layer and a battery piece in a photovoltaic module according to an embodiment of the present application;

fig. 7 is a schematic view of a second structure of an encapsulation layer in a photovoltaic module according to an embodiment of the present application;

FIG. 8 is a schematic cross-sectional view of the structure of FIG. 7 along the section B1-B2;

FIG. 9 is a first top view of a photovoltaic module according to an embodiment of the present application;

FIG. 10 is a schematic cross-sectional view of FIG. 9 taken along the line A1-A2;

fig. 11 is a schematic view of a second structure of a photovoltaic module according to an embodiment of the present application;

fig. 12 is a second top view of a photovoltaic module according to an embodiment of the present application;

FIG. 13 is a schematic cross-sectional view of the structure of FIG. 12 along the line A1-A2;

fig. 14 is a schematic view of a third structure of a photovoltaic module according to an embodiment of the present application.

Detailed Description

As known from the background art, the yield of the current photovoltaic module is poor.

The embodiment of the application provides a photovoltaic module, which comprises: a battery string, a first encapsulation layer, a second encapsulation layer; at least one of the first encapsulation layer or the second encapsulation layer comprises: the photovoltaic module comprises a main body part and a plurality of pre-crosslinking parts which penetrate the main body part in the thickness direction of the main body part and are distributed at intervals, wherein each pre-crosslinking part is used for being opposite to a battery piece, and each pre-crosslinking part is further located in an overlapping area, so that the degree of crosslinking of the pre-crosslinking parts is high, the fluidity is poor, a flowing packaging layer can be prevented from pushing a welding strip, the deviation between the welding strip and a thin grid line is caused, and the yield of the photovoltaic module is affected.

Embodiments of the present application will be described in detail below with reference to the attached drawings. However, it will be understood by those of ordinary skill in the art that in various embodiments of the present application, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the claimed technical solution of the present application can be realized without these technical details and various changes and modifications based on the following embodiments.

Fig. 1 is a schematic structural diagram of a photovoltaic module according to an embodiment of the present application; fig. 2 is a schematic structural diagram of a battery string in a photovoltaic module according to an embodiment of the present application; fig. 3 is a schematic structural diagram of a packaging layer in a photovoltaic module according to an embodiment of the present application; fig. 4 is a schematic view of a first structure of a package layer and a battery string in a photovoltaic module according to an embodiment of the present application; fig. 5 is a schematic view of a second structure of a packaging layer and a battery string in a photovoltaic module according to an embodiment of the present application; fig. 6 is a schematic structural diagram of a packaging layer and a battery piece in a photovoltaic module according to an embodiment of the present application; fig. 7 is a schematic view of a second structure of an encapsulation layer in a photovoltaic module according to an embodiment of the present application; FIG. 8 is a schematic cross-sectional view of the structure of FIG. 7 along the section B1-B2;

FIG. 9 is a first top view of a photovoltaic module according to an embodiment of the present application; FIG. 10 is a schematic cross-sectional view of FIG. 9 taken along the line A1-A2; fig. 11 is a schematic view of a second structure of a photovoltaic module according to an embodiment of the present application; fig. 12 is a second top view of a photovoltaic module according to an embodiment of the present application; FIG. 13 is a schematic cross-sectional view of the structure of FIG. 12 along the line A1-A2; fig. 14 is a schematic view of a third structure of a photovoltaic module according to an embodiment of the present application.

It should be noted that fig. 1 and 11 are exploded views of a photovoltaic module without lamination treatment, where the encapsulation layer still includes a first encapsulation layer and a second encapsulation layer respectively located at two sides of the battery piece. Fig. 10, 13 and 14 are schematic cross-sectional structures of the laminated photovoltaic module, in which the encapsulation layer is a whole and encapsulates all the strings and the solder strips, and at this time, there is no concept of the first encapsulation layer and the second encapsulation layer, and there is no concept of the body portion and the pre-crosslinking portion.

In order to facilitate description of the difference between the packaging layer before the lamination process and the packaging layer after the lamination process, the disclosed embodiment of the application uses different reference numerals to describe that the packaging layer before the lamination process is the packaging adhesive film 110, the packaging adhesive film 110 includes a first packaging layer 111 and a second packaging layer 112, and the packaging layer after the lamination process is the packaging layer 11. It is understood that the crosslinking degree and the adhesiveness of the encapsulating film 110 are smaller than those of the encapsulating layer 11.

The lamination treatment is used for enabling the packaging layer to be in a molten state, filling gaps between the battery strings and the adhesive film in the molten state, so that all components in the photovoltaic module are adhered together, and further complete packaging and protection of the battery piece are achieved. The lamination process is also used to achieve alloying between the grid line structure and the solder strip in the battery plate, and the alloying includes forming an alloy layer between the solder strip and the grid line structure, so as to achieve electrical connection between the solder strip and the battery plate.

According to some embodiments of the present application, an aspect of an embodiment of the present application provides a photovoltaic module, including: a plurality of battery strings 10, each battery string 10 including a plurality of battery cells 100. The photovoltaic module includes: a solder strip 201, wherein the solder strip 201 is used for electrically connecting every two adjacent battery pieces 100; wherein, the battery piece 100 and the welding strip 201 have an overlapping area 202. The photovoltaic module includes: a first encapsulation layer 111 and a second encapsulation layer 112, the first encapsulation layer 111 and the second encapsulation layer 112 respectively covering both sides of the battery string 10; at least one of the first encapsulation layer 111 or the second encapsulation layer 112 includes: the battery pack comprises a main body part 131 and a plurality of pre-crosslinking parts 132 penetrating the main body part 131 along the thickness direction of the main body part 131 and arranged at intervals, wherein each pre-crosslinking part 132 is opposite to each battery piece 100, and each pre-crosslinking part 132 is also positioned in an overlapping region 202; wherein, the crosslinking degree of the pre-crosslinking portion 132 is greater than that of the main body portion 131. The photovoltaic module includes: cover plate 14, cover plate 14 is located at a side of first encapsulation layer 111 away from battery string 10 and at a side of second encapsulation layer 112 away from battery string 10.

It should be noted that, the photovoltaic module protected by the embodiment of the present application is a photovoltaic module before lamination, where the encapsulation layer in the photovoltaic module still has the concepts of the first encapsulation layer and the second encapsulation layer.

In some embodiments, the battery plate 100 includes, but is not limited to, any of a PERC cell, a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact cell), a HIT/HJT cell (Heterojunction Technology, heterojunction cell).

In some embodiments, the cell sheet 100 may be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell, or a multi-compound solar cell, which may be specifically a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenium solar cell, or a perovskite solar cell.

In some embodiments, the battery piece 100 is a full back electrode contact crystalline silicon solar cell (Interdigitated back contact, IBC), where the IBC cell refers to a back junction back contact solar cell structure in which positive and negative metal electrodes are arranged on the back surface of the cell in an interdigital manner, and the PN junction and the electrodes thereof are located on the back surface of the cell, that is, the electrodes of the emitter region and the base region of the IBC cell are all located on the back surface, and the front surface is not shielded by a grid line, so that the photoelectric conversion performance of the cell can be improved.

The battery sheet 100 is a whole battery or a sliced battery. A sliced cell refers to a cell sheet formed by cutting a complete whole cell. The cutting process comprises the following steps: laser grooving+cutting (Linear Spectral Clustering, LSC) process and thermal stress cell separation (TMC) process. In some embodiments, the sliced cells are half-cells, which may also be understood as half-sliced cells or half-cells. The half-cell assembly functions to increase the generated power by reducing the resistance loss. From ohm's law, solar cell interconnect electrical losses are proportional to the square of the current magnitude. After the battery is cut into two halves, the current is reduced by half, and the electric loss is reduced to one quarter of the full-size battery loss. The increase in the number of cells also correspondingly increases the number of cell gaps that help to boost the short circuit current through reflection from the back plate of the assembly. In addition, cutting the half cell assembly can optimize the width of the cell solder strip, which conventionally requires an optimized balance between increasing the solder strip width to reduce electrical losses and decreasing the solder strip width to reduce shading losses. And the half-cut battery assembly reduces battery loss, so that the width of the welding strip can be set thinner to reduce shading loss, and the battery efficiency and the power generation power consumption are improved. In some embodiments, the sliced cell may be a three-slice cell, a 4-slice cell, an 8-slice cell, or the like.

In some embodiments, the battery cell 100 includes a plurality of gate line structures 101 arranged at intervals along the first direction. The grid line structure 101 is used for collecting photo-generated current in the solar cell 100 and leading to the outside of the cell.

The conventional battery sheet 100 includes a main grid line and an auxiliary grid line, the auxiliary grid line intersects with the extending direction of the main grid line, the auxiliary grid line is used for collecting current of the substrate, and the main grid line is used for collecting the current of the auxiliary grid line and transmitting the current to the welding strip. In some embodiments, the gate line structure 101 is a secondary gate line, which may also be referred to as a secondary gate line, which is used to conduct current. The battery piece 100 provided by the embodiment of the application does not comprise a main grid line, namely the battery piece 100 is of a design without a main grid, so that a carrier transport path is shortened, series resistance is reduced, the front light receiving area is increased, the power of a component is improved, the short circuit current is improved, and the use amount of grid line printing silver paste is reduced to reduce the production cost.

In some embodiments, the gate line structure 101 includes a first electrode and a second electrode. The first surface of the battery sheet 100 has a first electrode, which is one of a positive electrode or a negative electrode, and the opposite side to the first surface, i.e., the second surface has a second electrode, which is the other of the positive electrode or the negative electrode. When the battery piece is an IBC battery, the first electrode and the second electrode are positioned on the same side of the battery piece.

In some embodiments, the battery string 10 includes a plurality of battery cells 100, the plurality of battery cells 100 including a first battery cell and a second battery cell.

In some embodiments, the solder strips 201 are used to interconnect the battery cells 100 and concentrate the current transfer to elements external to the photovoltaic module. The solder ribbon 201 includes a bus ribbon for connecting the string of photovoltaic cells and the junction box, and an interconnect ribbon for connecting between the first and second cells.

In some embodiments, the solder strip 201 is a core-in structure, and the solder strip 201 includes a conductive layer and a solder layer covering a surface of the conductive layer. The conductive layer is the main conductive transport layer of the solder strip 201, so the lower the resistivity of the conductive layer, the smaller the electrical loss of the solder strip 201, and the better the battery efficiency and the generated power. The conductive layer is made of conductive materials with better conductivity such as copper, nickel, gold, silver and the like or alloy materials with low resistivity.

In some embodiments, the welding layer may be plated on the surface of the conductive layer or coated on the surface of the conductive layer, and specifically, the source material of the welding layer may be uniformly coated around the conductive layer according to a certain component proportion and thickness by using a special process such as electroplating, vacuum deposition, spraying or hot dip coating. The main function of the welding layer is to make the welding strip 201 meet the weldability, and to firmly weld the welding strip 201 on the grid line structure 101 of the battery piece 100, so as to perform a good current guiding function.

In some embodiments, the material of the solder layer is a metallic or alloy material having a lower melting point than the conductive layer, such as a tin alloy, which may include a tin-zinc alloy, a tin-bismuth alloy, or a tin-indium alloy. And the tin is used for welding a welding material, has a low melting point, has good affinity with metals such as copper and the like, and has good welding fastness. The lead in the tin-lead alloy can reduce the melting point of the welding strip, and the tin and the lead can form a eutectic point with the melting point of 183 ℃, so that the tin-lead alloy has good welding performance and usability. The disclosed embodiments can reduce the melting point temperature and surface tension by replacing lead with other metallic elements or adding other elements, such as bismuth, to the tin-lead alloy. The melting point of the tin-bismuth alloy can be reduced to 139 ℃ to meet the requirement of low-temperature welding.

In some embodiments, the solder layer has a flux therein, which refers to a chemical substance that aids and facilitates the soldering process during the soldering process, while having a protective effect, preventing oxidation reactions. The flux includes an inorganic flux, an organic flux, and a resin flux. It will be appreciated that the flux has a melting point lower than that of the solder layer and increases the fluidity of the molten solder layer to provide good alloying of the solder layer with the gate line structure 101.

In some embodiments, the cross-sectional shape of the solder strip 201 along the extension direction of the gate line structure 101 is circular, and the circular solder strip has no orientation problem and alignment problem, so that the circular solder strip is easier to mass produce.

In some embodiments, the cross-sectional shape of strap 201 may be triangular or any other shape to increase the contact area of the strap with the gate line structure and to reduce the problem of misalignment of strap 201 with gate line structure 101.

In some embodiments, the surface of the solder strip 201 remote from the battery cell 100 has a light reflective layer on the outer side of the solder layer remote from the conductive layer and the battery cell 100. The light reflecting layer serves to improve electrical loss due to the shielding area of the solder strip 201 to the battery cell 100.

In some embodiments, the outer surface of the solder layer has reflective grooves, which are concave grooves or trenches facing the conductive layer from the solder layer, and sunlight is reflected onto the battery plate 100 through the sidewalls of the reflective grooves, thereby improving the utilization rate of sunlight.

In some embodiments, the first battery cell and the second battery cell are connected in series or in parallel by a solder strip 201 to form a battery string. The welding strip 201 is connected with the first electrode of the first battery piece and the second electrode of the adjacent second battery piece, or the welding strip 201 is connected with the second electrode of the first battery piece and the first electrode of the adjacent second battery piece.

In some embodiments, referring to fig. 1, the first surfaces of the first and second battery pieces are all facing the same side, and the second surfaces of the first and second battery pieces are all facing the same side, or the first electrodes of all battery pieces are facing the same side, and the second electrodes of all battery pieces are facing the same side, then the solder strip 201 needs to naturally extend from the first surface of the battery piece to the second surface of the adjacent battery piece, so that the solder strip 201 connects the first electrode and the second electrode of the adjacent battery piece.

In some embodiments, referring to fig. 11, the first and second battery pieces are sequentially arranged in the order of the first surface, the second surface, the first surface, and the second surface, the solder strip 201 is not bent, and the solder strip 201 directly connects the first electrode of the first battery piece and the second electrode of the second battery piece adjacent thereto.

Wherein, the adjacent battery plates 100 shown in fig. 1 and 11 have a battery gap therebetween to achieve electrical insulation between the different battery plates 100. The adjacent battery sheets 100 shown in fig. 14 have no battery gap therebetween, i.e., the battery sheets 100 are stacked.

In some embodiments, the area where one solder strip 201 overlaps the battery cell is an overlapping area 202, and the overlapping area 202 includes the area where the solder strip 201 overlaps the grid line structure 101.

In some embodiments, adjacent battery strings 10 have a first spacing 21 therebetween and every second spacing 22 between two battery plates 100. The second gap 22 is the above-mentioned cell gap.

In some embodiments, the packaging film 110 includes a first packaging layer 111 and a second packaging layer 112, and at least one of the first packaging layer 111 and the second packaging layer 112 includes a main body portion 131 and a pre-crosslinked portion 132. The pre-crosslinking portion 132132 refers to a region where a portion of the adhesive film including the main body portion 131 is pre-treated to form a region having a large degree of crosslinking, that is, the pre-crosslinking portion 132 is essentially a portion of the adhesive film, but a portion of the adhesive film is pre-treated to have different properties, and the remaining adhesive film without the pre-treatment is used as the main body portion 131.

In some embodiments, the pretreatment may include a heat treatment or a light treatment, such as an infrared heat treatment or an ultraviolet light treatment, so that small molecules in the adhesive film are agglomerated into large molecules, thereby changing the crosslinking degree of the adhesive film itself.

In some embodiments, the degree of crosslinking of the pre-crosslinked portion 132 is less than or equal to 50%. The degree of crosslinking of the pre-crosslinked portion 132 is less than or equal to 48%, 46.5%, 43.3%, 40.2%, or 38.3%. The degree of crosslinking of the pre-crosslinked portion 132 may be 50%, 48.1%, 47.2%, 43.1%, 41.1%, 36.7%, 37.1%, 35%, or 30.4%.

In some embodiments, the degree of crosslinking of the pre-crosslinked portion 132 ranges from greater than 10% to less than 30%. The degree of crosslinking of the pre-crosslinked portion 132 may be 15%, 17.3%, 18.3%, 21.2%, 23.3%, 26.7%, 27.1%, 28%, or 29.4%.

The degree of crosslinking of the pre-crosslinking portion 132 is in the above-described arbitrary range, and the pre-crosslinking portion 132 itself has good adhesion, so that the relative position between the solder ribbon 201 and the battery sheet 100 is fixed, thereby avoiding the solder ribbon 201 from being shifted during the lamination process, and thus reducing the yield of the photovoltaic module.

The increase in the degree of crosslinking is generally accompanied by an increase in the melting point of the molten state, and the melting point of the pre-crosslinked portion 132 is greater than the melting point of the molten state of the main body portion 131, so that when the main body portion 131 is in the molten state, the pre-crosslinked portion 132 can also be in a more stable solid state, thereby preventing the main body portion 131 from pushing the solder strip 201 even to the overlapping region between the solder strip 201 and the battery piece 100, and thus affecting the welding performance of the battery piece 100 and the solder strip 201.

The cross-linking degree of the pre-cross-linking portion 132 is not too high, and the lamination problem during lamination treatment may be larger than the melting point of the pre-cross-linking portion 132, so that the packaging adhesive film 110 cannot fill the gap between the battery piece and the welding strip perfectly, and in the subsequent process, the problems of poor conditions such as ejection of the packaging adhesive film 110 and the like and strength reduction of the photovoltaic module and the like due to thermal expansion of air in the gap occur, and the yield and strength of the photovoltaic module are reduced.

The high degree of crosslinking of the pre-crosslinking portion 132 also causes an increase in viscosity and a decrease in toughness of the pre-crosslinking portion 132, and the increase in viscosity results in the inability of air located on the surface of the battery sheet 100 to be discharged, thereby reducing the yield of the photovoltaic module; the solder tape 201 may push the packaging film 110 through, or may cause a problem such as chipping.

In some embodiments, the body portion 131 and the pre-crosslinked portion 132 are an integrally formed structure. Thus, the main body 131 and the pre-crosslinking portion 132 may be formed of the same initial film layer, so as to reduce the interface state defect of the contact area between the main body 131 and the pre-crosslinking portion 132, ensure the sealing performance of the packaging adhesive film 110, and have good moisture isolation performance.

In some embodiments, the body portion 131 and the pre-crosslinked portion 132 are an integrally formed structure. In the lamination process, the main body 131 and the pre-crosslinking part 132 are made of the same material, the main body 131 and the pre-crosslinking part 132 can form an integral material packaging layer 11 after lamination, and interface states between materials or hybridization between molecules do not exist in each part of the packaging layer 11, so that the packaging layer 11 after lamination is an integral formed by a single substance, and the performance is more stable and uniform, thereby effectively isolating moisture.

By way of illustration, the degree of crosslinking of the main body 131 is greater than or equal to 0, and the embodiment of the present application does not limit the degree of crosslinking of the main body 131, but only requires that the degree of crosslinking of the main body 131 is less than the degree of crosslinking of the pre-crosslinked portion 132.

It can be understood that the degree of crosslinking of the encapsulant layer 11 in the photovoltaic module after lamination is greater than the degree of crosslinking of the main body portion 131 and greater than the degree of crosslinking of the pre-crosslinked portion 132, and not only the degree of crosslinking of the main body portion 131 but also the degree and performance of the pre-crosslinked portion 132 are changed during lamination.

In some embodiments, the pre-crosslinked portion 132 is opposite to the battery cell, including the pre-crosslinked portion 132 shown in fig. 4 completely overlapping the battery cell, the pre-crosslinked portion 132 shown in fig. 5 covering the battery cell, and a partial area of the pre-crosslinked portion 132 covering the first and second spaces 21 and 22, and the pre-crosslinked portion 132 being smaller than the area of the battery cell.

When the pre-crosslinked portion 132 is smaller than the area of the battery sheet 100, the pre-crosslinked portion 132 covers the overlapping area of the solder strip 201 and the battery sheet 100 due to a certain distance between the solder strip 201 and the end of the battery sheet 100, and exposes the area where the solder strip does not overlap the battery sheet, or the pre-crosslinked portion 132 does not completely cover the solder strip 201, and exposes a part of the overlapping area 202.

In some embodiments, when the pre-crosslinking portion 132 is opposite to the battery sheet 100, it is illustrated that the body portion 131 covers the first space 21 and the second space 22. The main body 131 covers the first interval 21 and the second interval 22, so that the main body 131 fills gaps between the battery pieces 100 and gaps between the battery strings 10 and 10, firstly, bubbles on the surfaces of the battery pieces 100 can be discharged through the gaps, so that series of problems caused by glue shortage are avoided, secondly, compared with the gaps between the battery pieces 100 and the gaps between the battery pieces 100 and the pre-crosslinking parts 132, the main body 131 with better fluidity is better, the strength is lower, the damage to the battery pieces 100 and the welding strips 201 is smaller, and the damage rate of the battery pieces is reduced. The main body 131 is located at the gap between the battery strings 10 and 10, and the filled encapsulation layer can reduce the amount of the empty glue to improve the strength of the photovoltaic module due to the larger gap between the battery strings 10.

In some embodiments, the first encapsulation layer 111 includes a body portion 131 and a pre-cross-linking portion 132; the ratio of the total area of the plurality of pre-cross-linking portions 132 to the total area of the first encapsulation layer 111 is less than or equal to 80% of the same first encapsulation layer 111. The ratio of the total area of the plurality of pre-crosslinking parts 132 to the total area of the first encapsulation layer 111 may be 79%, 76.5%, 73.9%, 71.5%, 68%, 66.2%, 65%, 63.1%, or 60%. The ratio of the total area of the plurality of pre-crosslinked portions 132 to the total area 111 of the first encapsulation layer is within the above arbitrary range or value, the ratio of the pre-crosslinked portions 132 to the main body portion 131 is large, so that most of the opposite areas of the battery piece 100 are the pre-crosslinked portions 132, and the difference between the areas or the coverage of the battery piece and the pre-crosslinked portions 132 is small, so that the pre-crosslinked portions 132 can perform more careful protection on the battery piece 100, thereby promoting less offset between the solder strip 201 and the battery piece 100, and improving the welding performance between the solder strip 201 and the battery piece 100.

On the contrary, when the ratio of the total area of the plurality of pre-crosslinked portions 132 to the total area of the first encapsulation layer 111 is greater than 80%, the ratio of the pre-crosslinked portions 132 in the entire first encapsulation layer 111 is too large, so that the air between the battery sheet 100 and the first encapsulation layer 111 cannot be completely exhausted, thereby affecting the yield of the photovoltaic module. Moreover, if the main body 131 occupies a relatively small amount, the flowability of the first encapsulation layer 111 itself is crossed, so that the first encapsulation layer 111 cannot completely fill all gaps and gaps between the battery pieces 100 and 100, and thus there is an empty glue and a decrease in the strength of the photovoltaic module, thereby reducing the yield of the photovoltaic module.

Similarly, when the second encapsulation layer 112 includes the main portion 131 and the pre-crosslinked portion 132; the ratio of the total area of the plurality of pre-cross-links 132 to the total area of the second encapsulation layer 112 is less than or equal to 80% of the same second encapsulation layer 112.

Referring to fig. 6, each pre-cross-link 132 is located in at least one overlap region 202.

It will be appreciated that to illustrate the various situations where the pre-crosslinked portion 132 is located in at least one overlap region 202, the pre-crosslinked portion 132 in the battery sheet shown in fig. 6 is located in at least one overlap region 202 comprising: in an actual photovoltaic module, the number of the pre-crosslinked portions 132 and the overlapping regions 202 in one cell is not limited, and only the pre-crosslinked portions 132 are located in at least one overlapping region 202, in which the pre-crosslinked portions 132 are located in one overlapping region 202, the pre-crosslinked portions 132 are located in two overlapping regions 202, and the pre-crosslinked portions 132 are located in three overlapping regions 202.

In some embodiments, each pre-cross-link 132 is located in at least two adjacent overlap regions 202 and a battery sheet region between two adjacent overlap regions 202. In this way, the relative contact area between the pre-crosslinked portion 132 and the battery sheet 100 increases, and the adhesion area between the pre-crosslinked portion 132 and the battery sheet 100 also increases, so that the fixing effect and fixing effect of the pre-crosslinked portion 132 on the solder strip 201 are also enhanced, thereby firmly fixing the solder strip 201 on the surface of the battery sheet 100, and preventing the solder strip 201 from being deviated.

In some embodiments, for the same battery sheet 100, the ratio of the total area of the pre-cross-linking portions 132 to the area of the battery sheet 100 is S, which satisfies: s is more than or equal to 10% and less than or equal to 1.S satisfies: s is more than or equal to 10% and less than or equal to 25%, S is more than or equal to 25% and less than or equal to 36%, S is more than or equal to 36% and less than or equal to 49%, S is more than or equal to 49% and less than or equal to 63%, S is more than or equal to 63% and less than or equal to 80% or more than or equal to 80% and less than or equal to 100%. S may be 12%, 26%, 38%, 49%, 58%, 63%, 76%, 82%, 94% or 100%.

The ratio S of the total area of the pre-crosslinking portion 132 to the area of the battery plate 100 is within the above-mentioned arbitrary range or arbitrary value, and the area of the pre-crosslinking portion 132 surrounding the battery plate 100 is larger, so that a perfect protection is formed for the battery plate 100 to prevent the solder strip 201 from being deviated. The pre-crosslinking portion 132 is also used to avoid the influence of the molten main portion 131 on the welding performance of the strap 201 and the grid line structure 101, thereby improving the welding performance of the battery piece and the strap 201.

In some embodiments, referring to fig. 7 and 8, the first encapsulation layer 111 or the second encapsulation layer 112 further includes: at least one adhesive film 133, wherein the at least one adhesive film 133 is positioned on one side of the main body portion 131 and the pre-crosslinking portion 132 away from the battery string 10, and the crosslinking degree of each adhesive film 133 is smaller than that of the pre-crosslinking portion 132; the material of the adhesive film 133 is different from that of the main body 131. The adhesive film 133 may improve the adhesion between the first or second encapsulation layer 111 or 112 and the cover plate 14.

In some embodiments, the at least one adhesive film 133 includes a first adhesive film and a second adhesive film, the first adhesive film is located between the main body 131 and the second adhesive film, and the crosslinking degree of the first adhesive film is greater than or equal to the crosslinking degree of the second adhesive film.

In some embodiments, the melting point of the packaging film 110 is less than the lamination temperature during the lamination process, the packaging film 110 is a film layer formed by the molecules in a cross-linked state formed by the molecules in a melt state of the film at the temperature of the laminator due to the initiator in the packaging film 110.

In some embodiments, the material of the encapsulating film 110 includes an organic encapsulating film such as an Ethylene Vinyl Acetate (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyvinyl butyral (PVB) film.

In some embodiments, the melting point of the packaging film 110 and the melting point of the solder strip 201 can be set according to practical requirements. When the melting point of the packaging film 110 is greater than that of the solder strip 201, the solder strip 201 can realize alloying before the packaging film 110 is in a molten state, so that the molten packaging film 110 can be effectively prevented from being immersed into the grid line structure 101 and the connecting component 110 and pushing the solder strip 201 to deviate. When the melting point of the packaging adhesive film 110 is smaller than that of the solder strip 201, the lamination temperature can be set to be lower, so that the thermal stress of the battery piece is improved, and the yield of the photovoltaic module is improved.

In some embodiments, the cover 14 may be a glass cover, a plastic cover, or the like having a light-transmitting function. Specifically, the surface of the cover plate 14 away from the encapsulation film 110 may be a concave-convex surface, so as to increase the utilization rate of the incident light. The cover 14 includes a first cover plate opposite to the first surface of the battery cell 10 and a second cover plate opposite to the second surface of the battery cell 10.

In the photovoltaic module provided by the embodiment of the present application, at least one of the first encapsulation layer 111 or the second encapsulation layer 112 includes: the photovoltaic module comprises a main body part 131 and a plurality of pre-crosslinking parts 132 penetrating the main body part 131 along the thickness direction of the main body part 131 and distributed at intervals, wherein each pre-crosslinking part 132 is used for being opposite to the cell 100, and each pre-crosslinking part 132 is also positioned in an overlapping area 202, so that the degree of crosslinking of the pre-crosslinking parts 132 is large, the fluidity is poor, and the phenomenon that a flowing packaging layer pushes a welding strip to cause deviation between the welding strip and a fine grid line to influence the yield of the photovoltaic module can be avoided.

In addition, the pre-crosslinking portion 132 is used for being opposite to the battery piece 100, that is, the main body portion 131 is located in an area other than the battery piece, such as a gap between battery strings and a gap between battery pieces, so as to fill the gap between the battery pieces and the gap between the battery strings, firstly, bubbles on the surface of the battery piece can be discharged through the gap, so that series of problems caused by glue shortage are avoided, secondly, compared with the gap between the battery pieces and the pre-crosslinking portion 132, the main body portion 131 with better fluidity is located in the gap between the battery pieces, so that the strength is lower, the damage to the battery pieces and the welding strip is smaller, and the damage rate of the battery pieces is reduced. The main body 131 is located in the gap between the battery strings, and the filled encapsulation layer can reduce the amount of the empty glue to improve the strength of the photovoltaic module due to the larger gap between the battery strings.

Correspondingly, according to some embodiments of the present application, another aspect of the embodiments of the present application further provides a method for manufacturing a photovoltaic module, which may be used to manufacture the photovoltaic module provided in the foregoing embodiments. The same or corresponding technical features as those of the above embodiment are not described in detail herein.

Referring to fig. 2, the preparation method includes: providing a plurality of battery pieces 100 and solder strips 201; the solder strip 201 electrically connects each two adjacent battery cells 100 to form the battery string 10, and the solder strip 201 has an overlap region 202 with the battery cells 100.

In some embodiments, the battery sheet 100 may include a first battery sheet and a second battery sheet. The first battery cells and the second battery cells are connected in series or in parallel by the solder strip 201 to form the battery string 10. The welding strip 201 is connected with the first electrode of the first battery piece and the second electrode of the adjacent second battery piece, or the welding strip 201 is connected with the second electrode of the first battery piece and the first electrode of the adjacent second battery piece.

In some embodiments, referring to fig. 2, the first surfaces of the first and second battery pieces are all facing the same side, and the second surfaces of the first and second battery pieces are all facing the same side, or the first electrodes of all battery pieces are facing the same side, and the second electrodes of all battery pieces are facing the same side, then the solder strip 201 needs to naturally extend from the first surface of the battery piece to the second surface of the adjacent battery piece, so that the solder strip 201 connects the first electrode and the second electrode of the adjacent battery piece.

Wherein, the adjacent battery plates 10 shown in fig. 2 and 11 have a battery gap therebetween to achieve electrical insulation between the different battery plates 100. The adjacent battery pieces shown in fig. 14 have no battery gap therebetween, i.e., the battery pieces are stacked.

Referring to fig. 1 or 11, the preparation method includes: providing a first packaging layer 111 and a second packaging layer 112, wherein the first packaging layer 111 and the second packaging layer 112 respectively cover two sides of the battery string 10; at least one of the first packaging layer 111 or the second packaging layer 112 comprises a main body portion 131 and a plurality of pre-crosslinking portions 132 penetrating the main body portion 131 along the thickness direction of the main body portion 131 and arranged at intervals, each pre-crosslinking portion is opposite to each battery piece, and each pre-crosslinking portion 132 is also located in the overlapping region 202; wherein, the crosslinking degree of the pre-crosslinking part 132 is greater than that of the main body part 131; a cover plate 14 is provided, the cover plate 14 covering a side of the first encapsulation layer 111 remote from the battery string 10 and a side of the second encapsulation layer 112 remote from the battery string 10.

In some embodiments, adjacent battery strings 10 have a first spacing 21 therebetween and every second spacing 22 between two battery plates 100. The pre-crosslinking portion 132 faces the battery sheet 100, and the main body portion 131 covers the first space 21 and the second space 22.

In some embodiments, the degree of crosslinking of the pre-crosslinked portion 132 is less than or equal to 50%.

In some embodiments, the body portion 131 and the pre-crosslinked portion 132 are an integrally formed structure.

In some embodiments, providing the first encapsulation layer 111 or the second encapsulation layer 112 includes: providing an initial packaging layer; pre-treating the initial packaging layer of the partial area, wherein the pre-treatment is used for increasing the crosslinking degree of the initial packaging layer of the partial area; the pre-processed initial encapsulation layer is used as a pre-crosslinking portion 132, the initial encapsulation layer without pre-processing is used as a main body portion 131, and the pre-crosslinking portion 132 and the main body portion 131 form a first encapsulation layer or a second encapsulation layer.

In some embodiments, the material of the initial encapsulation layer includes an organic encapsulation film such as an Ethylene Vinyl Acetate (EVA) film, a polyethylene octene co-elastomer (POE) film, or a polyvinyl butyral (PVB) film.

In some embodiments, providing an initial encapsulation layer includes: providing a first initial film and a second initial film; typesetting the first initial film and the second initial film; calendering the first initial film and the second initial film to form an initial packaging layer; wherein the pretreated first initial film is used as the pre-crosslinking portion 132, and the untreated second initial film is used as the main body portion 131.

In some embodiments, the material of the pre-crosslinked portion 132 may be different from the material of the main body portion 131, and by reasonably setting the material of the pre-crosslinked portion 132 to be different from the material of the main body portion 131, for example, setting the melting point of the material of the pre-crosslinked portion 132 to be greater than the melting point of the main body portion 131, the pre-crosslinked portion 132 can still ensure a relatively stable form when the main body portion 131 is in a molten state, so as to provide good protection to the solder strip. The good protection includes preventing the molten adhesive film from pushing the solder strip to shift and preventing the molten main body 131 from immersing between the solder strip 201 and the grid line structure, so that the problem of poor soldering effect is caused.

For another example, the fluidity or adhesiveness of the material of the main body 131 is smaller than that of the material of the pre-crosslinked portion 132, so that the main body 131 can fill gaps between the battery pieces and gaps between the battery strings, firstly, bubbles on the surfaces of the battery pieces can be discharged through the gaps, so that series of problems caused by glue shortage are avoided, secondly, the main body 131 with better fluidity is located in the gaps between the battery pieces, the fluidity of the main body 131 is better, the strength is lower, damage to the battery pieces and the welding strips is also smaller, and the damage rate of the battery pieces is reduced. The main body 131 is located in the gap between the battery strings, and the filled encapsulation layer can reduce the amount of the empty glue to improve the strength of the photovoltaic module due to the larger gap between the battery strings.

In some embodiments, providing an initial encapsulation layer and pre-processing the initial encapsulation layer includes: providing a third initial film and a fourth initial film, wherein an initiator is arranged in the third initial film; calendering the third initial film and the fourth initial film to form an initial packaging layer; wherein the fourth initial film is positioned at one side of the third initial film; preprocessing an initial packaging layer of a partial area; wherein, the initial packaging layer of the partial area containing the initiator is pretreated and then used as a pre-crosslinking part 132, the initial packaging layer of the partial area containing the initiator is not pretreated and used as a main body part 131, and the initial packaging layer without the initiator is used as a glue film; the pre-crosslinking portion 132, the main body portion 131, and the adhesive film constitute a first encapsulation layer or a second encapsulation layer.

In some embodiments, referring to fig. 13, 14, and 10, the method of making further comprises: lamination is performed for forming a photovoltaic module.

In some embodiments, alloying between the solder strip and the gate line structure 101 is achieved during the lamination process.

In some embodiments, between laying the first encapsulation layer and the second encapsulation layer, further comprising: when the welding process is performed on the welding strip, and the welding process is used for making the welding strip 201 and the grid line structure 101 partially intersect area alloy contact, the relative position of the welding strip 201 and the grid line structure 101 can be positioned, and the damage to the battery piece 10 caused by the long-time welding process can be reduced.

Wherein the degree of alloying between the bonding strap and the gate line structure is different in the bonding process for making the bonding strap 201 in alloy contact with the partially intersecting region of the gate line structure 101 than in the lamination process for making the bonding strap 201 in full alloy contact with the intersecting region of the gate line structure 101. For example, in the soldering process, the solder ribbon 201 is in alloy contact with 20% of the intersection region of the gate line structure 101, and the solder ribbon 201 in the lamination process is in alloy contact with 80% of the intersection region of the gate line structure 101.

It can be appreciated that the encapsulating film 110 is converted into the encapsulating layer 11 after lamination. The materials are the same but the degree of crosslinking is different.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of carrying out the application and that various changes in form and details may be made therein without departing from the spirit and scope of the application. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the application, and the scope of the application should be assessed accordingly to that of the appended claims.

Claims

1. A photovoltaic module, comprising:

A plurality of battery strings, each of the battery strings including a plurality of battery cells;

the welding strip is used for electrically connecting every two adjacent battery pieces; wherein, the battery piece and the welding strip are provided with an overlapping area;

the first packaging layer and the second packaging layer cover two sides of the battery string respectively; at least one of the first encapsulation layer or the second encapsulation layer comprises:

the device comprises a main body part and a plurality of pre-crosslinking parts penetrating the main body part in the thickness direction of the main body part and arranged at intervals, wherein each pre-crosslinking part is opposite to each battery piece, and each pre-crosslinking part is also positioned in the overlapping area; wherein the degree of crosslinking of the pre-crosslinked portion is greater than the degree of crosslinking of the main body portion;

and the cover plate is positioned on one side of the first packaging layer far away from the battery string and one side of the second packaging layer far away from the battery string.

2. The photovoltaic module of claim 1, wherein adjacent strings have a first spacing therebetween and each two of the cells have a second spacing therebetween; the main body portion covers the first and second spaces.

3. The photovoltaic module of claim 1, wherein the first encapsulant layer comprises the body portion and the pre-crosslinking portion; and the ratio of the total area of the plurality of pre-crosslinking parts to the total area of the first packaging layer is less than or equal to 80 percent.

4. The photovoltaic module of claim 1, wherein the degree of crosslinking of the pre-crosslinking is less than or equal to 50%.

5. The photovoltaic assembly of claim 1, wherein the first encapsulation layer or the second encapsulation layer further comprises: at least one layer of adhesive film, the at least one layer of adhesive film is positioned on one side of the main body part and the pre-crosslinking part away from the battery string, and the crosslinking degree of each adhesive film is smaller than that of the pre-crosslinking part; the material of the adhesive film is different from the material of the main body part.

6. The photovoltaic module of claim 5, wherein the at least one layer of adhesive film comprises a first adhesive film and a second adhesive film, the first adhesive film is located between the main body portion and the second adhesive film, and the degree of crosslinking of the first adhesive film is greater than or equal to the degree of crosslinking of the second adhesive film.

7. The photovoltaic module of claim 1, wherein the body portion and the pre-cross-linking portion are of an integrally formed structure.

8. The photovoltaic module of claim 1, wherein each of the pre-cross-links is located in at least one of the overlap regions; alternatively, each of the pre-crosslinking regions is located in at least two adjacent overlap regions and a battery cell region between the two adjacent overlap regions.

9. The photovoltaic module of claim 8, wherein for the same cell, the ratio of the total area of the pre-cross-links to the area of the cell is S, S: s is more than or equal to 10% and less than or equal to 1.

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

providing a plurality of battery pieces and welding strips;

the welding strip is electrically connected with every two adjacent battery pieces to form a battery string, and the welding strip and the battery pieces are provided with overlapping areas;

providing a first packaging layer and a second packaging layer, wherein the first packaging layer and the second packaging layer respectively cover two sides of the battery string; at least one of the first packaging layer or the second packaging layer comprises a main body part and a plurality of pre-crosslinking parts penetrating through the main body part along the thickness direction of the main body part and arranged at intervals, each pre-crosslinking part is opposite to each battery piece, and each pre-crosslinking part is also positioned in the overlapping area; wherein the degree of crosslinking of the pre-crosslinked portion is greater than the degree of crosslinking of the main body portion;

A cover plate is provided, and covers one side of the first packaging layer far away from the battery string and one side of the second packaging layer far away from the battery string.

11. The method of manufacturing a photovoltaic module according to claim 10, wherein providing the first encapsulation layer or the second encapsulation layer comprises:

providing an initial packaging layer;

pre-treating the initial packaging layer of the partial area, wherein the pre-treatment is used for increasing the crosslinking degree of the initial packaging layer of the partial area; the initial packaging layer after pretreatment is used as a pre-crosslinking part, the initial packaging layer without pretreatment is used as a main body part, and the pre-crosslinking part and the main body part form a first packaging layer or a second packaging layer.

12. The method of manufacturing a photovoltaic module according to claim 11, wherein providing an initial encapsulation layer comprises:

providing a first initial film and a second initial film;

typesetting the first initial film and the second initial film;

calendering the first initial film and the second initial film to form an initial packaging layer; wherein the first initial film after pretreatment is used as a pre-crosslinking part, and the second initial film without pretreatment is used as a main body part.

13. The method of claim 12, wherein providing an initial encapsulation layer and pre-treating the initial encapsulation layer comprises:

providing a third initial film and a fourth initial film, wherein the third initial film is internally provided with an initiator;

calendering the third initial film and the fourth initial film to form an initial packaging layer; wherein the fourth initial film is positioned on one side of the third initial film;

preprocessing the initial packaging layer of a partial area; the initial packaging layer of the partial area containing the initiator is used as a pre-crosslinking part after being pretreated, the initial packaging layer of the partial area containing the initiator is used as a main body part without being pretreated, and the initial packaging layer without the initiator is used as a glue film; the pre-crosslinking part, the main body part and the adhesive film form a first packaging layer or a second packaging layer.