Photovoltaic module and preparation method thereof

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a photovoltaic module and a preparation method thereof, the photovoltaic module comprises a plurality of battery pieces, the surfaces of the battery pieces are provided with a plurality of fine grids arranged at intervals along a first direction, and the fine grids extend along a second direction; the bonding part is positioned on the surface of the battery piece; the electric connecting part is arranged on the surface of the battery piece, extends in the first direction, is used for being electrically connected with the fine grids and is embedded into the bonding part so that the bonding part can fix the electric connecting part on the battery piece, and the top surface of the electric connecting part is exposed from the top surface of the bonding part; wherein on a plane perpendicular to the first direction and the second direction, the height of the bonding part is a first height H1, the height of the electric connection part is a second height H2, and the first height H1 and the second height H2 meet the condition that H1 is larger than or equal to 0.5 H2 and smaller than or equal to 0.8 H2. According to the embodiment of the invention, the preparation efficiency and yield of the photovoltaic module can be improved at least, and the preparation cost of the photovoltaic module is reduced.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a photovoltaic module and its preparation method. Background Technology

[0002] As photovoltaic (PV) modules have evolved, the manufacturing cost and power generation of the solar cells have become the main factors restricting their development. In terms of cell manufacturing costs, silicon accounts for 60%–70% of the material cost, while the silver paste required for the cell grid accounts for 20%–30%. Therefore, the development of gridless technology to reduce the cost of silver paste reflects a strong desire to lower cell manufacturing costs. This technology also helps increase the effective light-emitting area of ​​the cells, thereby increasing power generation.

[0003] In photovoltaic modules containing gridless cells, electrical connectors are typically used to connect multiple fine grids on the cells, and adhesives are used to fix the electrical connectors to the cells. However, the electrical connectors and adhesives in the related technologies have certain problems, resulting in low manufacturing efficiency and yield of photovoltaic modules and high manufacturing costs. Summary of the Invention

[0004] This disclosure provides a photovoltaic module and its manufacturing method, which can at least improve the manufacturing efficiency and yield of the photovoltaic module and reduce the manufacturing cost of the photovoltaic module.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a photovoltaic module, including: a plurality of solar cells, the surface of each solar cell having a plurality of fine grids spaced apart along a first direction, the fine grids extending along a second direction; an adhesive portion located on the surface of the solar cells; and an electrical connection portion disposed on the surface of the solar cells and extending along the first direction, the electrical connection portion being used for electrical connection with the plurality of fine grids, wherein the electrical connection portion is embedded within the adhesive portion so that the adhesive portion fixes the electrical connection portion to the solar cells, and the top surface of the electrical connection portion protrudes from the top surface of the adhesive portion; wherein, in a plane perpendicular to the first direction and the second direction, the height of the adhesive portion is a first height H1, and the height of the electrical connection portion is a second height H2, the first height H1 and the second height H2 satisfying: 0.5H2≤H1≤0.8H2.

[0006] In some embodiments, the photovoltaic module includes a plurality of adhesive portions, at least one of the adhesive portions being located between adjacent fine grids, and in the first direction, the length of the adhesive portion is a first length L1, and the distance between two fine grids adjacent to the adhesive portion is a first spacing D1; wherein, L1 / D1≤0.8.

[0007] In some embodiments, in the first direction, the distance between the adhesive portion and the fine grid adjacent to the adhesive portion is a second spacing D2, where D2 ≥ 0.2 mm.

[0008] In some embodiments, the length of the adhesive portion in the second direction is a second length L2, where 1.0 mm ≤ L2 ≤ 2.0 mm.

[0009] In some embodiments, the adhesive portion includes a first sub-adhesive portion and a second sub-adhesive portion, the first sub-adhesive portion and the second sub-adhesive portion are located on opposite sides of the electrical connection portion, the direction of the first sub-adhesive portion pointing to the second sub-adhesive portion is parallel to the second direction; in the second direction, the length of the first sub-adhesive portion is a third length L3, the length of the second sub-adhesive portion is a fourth length L4, and the ratio of L3 to L4 is 2:9 to 9:2.

[0010] According to some embodiments of this disclosure, another aspect of this disclosure provides a method for manufacturing a photovoltaic module, comprising: providing a plurality of solar cells, the surface of each solar cell having a plurality of fine grids spaced apart along a first direction, the fine grids extending along a second direction; forming an initial bonding portion on the surface of the solar cells; providing an electrical connection portion disposed on the surface of the solar cells and extending along the first direction, the electrical connection portion being used for electrical connection with the plurality of fine grids, the electrical connection portion being embedded within the initial bonding portion, and the top surface of the electrical connection portion being exposed from the top surface of the initial bonding portion; curing the initial bonding portion to transform the initial bonding portion into an adhesive portion, the adhesive portion being used to fix the electrical connection portion to the solar cells; wherein, on a plane perpendicular to the first direction and the second direction, the height of the adhesive portion is a first height H1, the height of the electrical connection portion is a second height H2, and the first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2.

[0011] In some embodiments, forming the initial adhesive portion on the surface of the battery cell includes: providing a screen having a plurality of through holes spaced apart; placing the screen on the battery cell such that the plurality of through holes correspond to the area of ​​the battery cell to which the initial adhesive portion is to be applied; and performing screen printing to dispose of adhesive material within the plurality of through holes to form the initial adhesive portion on the battery cell; wherein, in a plane perpendicular to the first direction and the second direction, the height of the screen is a third height H3, 100μm≤H3≤400μm.

[0012] In some embodiments, the thixotropic index Ti of the adhesive material satisfies: 2.4 ≤ Ti ≤ 6.

[0013] In some embodiments, the width of the initial adhesive portion in the first direction is a second width W2; wherein, 0.2mm≤W2≤0.5mm.

[0014] In some embodiments, when the screen is placed on the battery cell, the width of the through hole in the first direction is a third width W3, and the distance between two adjacent fine grids of the through hole is a first spacing D1, satisfying W3 / D1≤0.6.

[0015] The technical solutions provided in this disclosure have at least the following advantages:

[0016] The photovoltaic module technical solution provided in this disclosure includes: a plurality of solar cells, the surface of which has a plurality of fine grids spaced apart along a first direction, the fine grids extending along a second direction; an adhesive portion located on the surface of the solar cells; and an electrical connection portion disposed on the surface of the solar cells and extending along the first direction, the electrical connection portion being used for electrical connection with the plurality of fine grids, wherein the electrical connection portion is embedded in the adhesive portion so that the adhesive portion fixes the electrical connection portion to the solar cells, and the top surface of the electrical connection portion protrudes from the top surface of the adhesive portion; wherein, on a plane perpendicular to the first direction and the second direction, the height of the adhesive portion is a first height H1, and the height of the electrical connection portion is a second height H2, the first height H1 and the second height H2 satisfying: 0.5H2≤H1≤0.8H2. In the photovoltaic modules provided in this disclosure, the height of the adhesive portion is within the aforementioned range. This avoids the problem of insufficient adhesion between the adhesive portion and the electrical connection portion due to an excessively low adhesive portion height, which could lead to misalignment of the electrical connection portion during the use or fabrication of the photovoltaic module. This improves the yield rate of the photovoltaic module. It also avoids the problem of excessively high cost due to excessive adhesive portion height and the resulting large amount of adhesive used. Furthermore, it avoids the excessive contact and bonding force between the tooling used to place the electrical connection portion and the adhesive portion during placement, thus preventing the tooling and adhesive portion from requiring excessive time to separate due to the large bonding force. Consequently, the fabrication time of the photovoltaic module can be reduced, thereby improving its fabrication efficiency. In other words, by ensuring the adhesive portion height is within the aforementioned range, the required adhesion force between the adhesive portion and the electrical connection portion can be met while saving adhesive portion material, thereby reducing the fabrication cost of the photovoltaic module and improving its fabrication efficiency. Attached Figure Description

[0017] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a partial 3D view of a photovoltaic module in related technologies;

[0019] Figure 2 This is a partial cross-sectional view of a photovoltaic module in related technologies;

[0020] Figure 3 This is another partial cross-sectional view of a photovoltaic module in related technologies;

[0021] Figure 4 A partial perspective view of a photovoltaic module provided in an embodiment of this disclosure;

[0022] Figure 5 A partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure;

[0023] Figure 6 A partial top view of a photovoltaic module provided in an embodiment of this disclosure;

[0024] Figure 7 Another partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure;

[0025] Figure 8 A schematic diagram of an initial adhesive portion and an adjacent fine grid provided in an embodiment of this disclosure;

[0026] Figure 9 This is a partial top view of the mesh of the screen provided in an embodiment of the present disclosure and the fine grid on the battery cell. Detailed Implementation

[0027] Figure 1 This is a partial 3D view of a photovoltaic module in related technologies. Figure 2 This is a partial cross-sectional view of a photovoltaic module in related technologies. Figure 3 This is another partial cross-sectional view of a photovoltaic module in related technologies. It should be noted that... Figure 1 The adhesive portion is not shown in the diagram.

[0028] Reference Figures 1 to 3The photovoltaic module in the related technology includes: multiple solar cells 100, an adhesive portion 101, and an electrical connection portion 102. The surface of each solar cell has multiple fine grids 103 arranged at intervals along a first direction X, and the fine grids 103 extend along a second direction Y. The adhesive portion 101 is located on the surface of the solar cell 100. The electrical connection portion 102 is disposed on the surface of the solar cell 100 and extends along the first direction X. The electrical connection portion 102 is used for electrical connection with the multiple fine grids 103. The electrical connection portion 102 is embedded within the adhesive portion 101 so that the adhesive portion 101 fixes the electrical connection portion 102 to the solar cell 100, and the top surface of the electrical connection portion 102 protrudes from the top surface of the adhesive portion 101. In a plane perpendicular to the first direction X and the second direction Y, refer to... Figure 2 If the height H1 of the adhesive portion 101 is too low, the adhesion between the adhesive portion 101 and the electrical connection portion 102 will be too weak. This will cause the position of the electrical connection portion 102 to shift during the use or fabrication of the photovoltaic module, resulting in a low yield rate for the photovoltaic module. (Reference) Figure 3 The excessive height H1 of the adhesive portion 101 results in a large amount of adhesive portion 101 being used, leading to higher costs for the photovoltaic module. Furthermore, the excessive height H1 of the adhesive portion 101 causes significant adhesive force between the tooling for placing the electrical connection portion 102 and the adhesive portion 101 when the electrical connection portion 102 is placed on the surface of the cell 100. This strong adhesive force requires a longer separation time, resulting in a longer manufacturing time and lower manufacturing efficiency for the photovoltaic module.

[0029] Therefore, the manufacturing efficiency and yield of photovoltaic modules in related technologies are relatively low, and the manufacturing cost is relatively high.

[0030] In the photovoltaic module provided in this embodiment, on a plane perpendicular to the first and second directions, the height of the adhesive portion is a first height H1, and the height of the electrical connection portion is a second height H2. The first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2. The heights of the adhesive portion and the electrical connection portion are within the above range. This avoids the problem of insufficient adhesion between the adhesive portion and the electrical connection portion due to an excessively low adhesive portion height, which could cause the electrical connection portion to shift during the use or fabrication of the photovoltaic module. This improves the yield of the photovoltaic module. It also avoids the problem of excessively high cost due to excessively high adhesive portion height, which would result in a large amount of adhesive used. Furthermore, it avoids the problem of excessively high adhesive portion height causing contact and a large adhesive force between the tooling for placing the electrical connection portion after the adhesive portion is formed. This avoids the need for a long time to separate the tooling from the adhesive portion due to a large adhesive force, thus reducing the fabrication time of the photovoltaic module and improving its fabrication efficiency.

[0031] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0032] Figure 4 This is a partial perspective view of a photovoltaic module provided in an embodiment of this disclosure. Figure 5 This is a partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure.

[0033] Reference Figure 4 and Figure 5 The photovoltaic module includes: multiple solar cells 200, an adhesive portion 201, and an electrical connection portion 202. The surface of the solar cells 200 has multiple fine grids 203 arranged at intervals along a first direction X, and the fine grids 203 extend along a second direction Y. The adhesive portion 201 is located on the surface of the solar cells 200. The electrical connection portion 202 is disposed on the surface of the solar cells 200 and extends along the first direction X. The electrical connection portion 202 is used for electrical connection with the multiple fine grids 203. The electrical connection portion 202 is embedded in the adhesive portion 201 so that the adhesive portion 201 fixes the electrical connection portion 202 to the solar cells 200, and the top surface of the electrical connection portion 202 protrudes from the top surface of the adhesive portion 201. In a plane perpendicular to the first direction X and the second direction Y, the height of the adhesive portion 201 is a first height H1, and the height of the electrical connection portion 202 is a second height H2. The first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2.

[0034] The solar cell 200 is used to absorb sunlight and convert light energy into electrical energy.

[0035] In some embodiments, the solar cell 200 can be a gridless solar cell. In other embodiments, the solar cell can be a grid-connected solar cell, with the electrical connection portion connected to the grid and the grid portion connected to the fine grid.

[0036] In some embodiments, the solar cell 200 includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter RearCell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology), thin-film solar cells, and tandem solar cells. Thin-film solar cells include, but are not limited to, perovskite thin-film solar cells, copper indium selenide (CIGS) thin-film solar cells, gallium arsenide (GaAs) thin-film solar cells, and cadmium sulfide (CdS) thin-film solar cells. Tandem solar cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0037] In some embodiments, the solar cell 200 can be a monocrystalline silicon photovoltaic cell, a polycrystalline silicon photovoltaic cell, an amorphous silicon photovoltaic cell, or a multi-component compound photovoltaic cell. Specifically, the multi-component compound photovoltaic cell can be a cadmium sulfide photovoltaic cell, a gallium arsenide photovoltaic cell, a copper indium selenide photovoltaic cell, or a perovskite photovoltaic cell.

[0038] The surface of the solar cell 200 has multiple fine grids 203 arranged at intervals along a first direction. The fine grids 203 are used to collect the photocurrent generated by the solar cell 200 and conduct it to the electrical connection portion 202.

[0039] The adhesive part 201 is used to bond and fix the electrical connection part 202.

[0040] In some embodiments, the adhesive portion 201 comprises acrylic, epoxy resin, or silicone. The adhesive portion 201 has good adhesive strength, can be used to fix the electrical connection portion 201, and has good insulation properties.

[0041] The electrical connection part 202 is used to connect with the fine grid 203 to collect the current on the fine grid 203. The electrical connection part 202 can be carbon steel welding wire, aluminum alloy welding wire, copper welding wire, etc.

[0042] Table 1 is a statistical table of the adhesive force between the adhesive part and the electrical connection part at different adhesive part heights.

[0043] Table 1

[0044]

[0045]

[0046] It should be noted that the adhesive force shown in Table 1 is the adhesive force between a single adhesive part and an electrical connection part. In photovoltaic modules, electrical connections parts can be fixed by one or more adhesive parts.

[0047] As can be seen from Table 1, the adhesive force between the adhesive portion 201 and the electrical connection portion 202 is positively correlated with the height H1 of the adhesive portion 201. In the embodiment of this disclosure, the height H1 of the adhesive portion 201 is greater than or equal to 0.5H2, and there is a large adhesive force between the adhesive portion 201 and the electrical connection portion 202, so that the adhesive portion 201 can fix the electrical connection portion 202 well.

[0048] It should be noted that, Figure 5 The cross-section of the electrical connection shown in the figure is circular. In reality, the cross-section of the electrical connection can also be triangular, rectangular or other shapes. The embodiments disclosed herein do not limit the cross-sectional shape of the electrical connection.

[0049] Figure 6 This is a partial top view of a photovoltaic module provided in an embodiment of this disclosure. It should be noted that... Figure 6 The illustration only shows the positional relationship between one adhesive part and two adjacent fine grids. In reality, a photovoltaic module may include multiple adhesive parts and multiple fine grids. The embodiments disclosed herein do not limit the number of adhesive parts or the number of fine grids.

[0050] refer to Figure 6 In some embodiments, the photovoltaic module includes a plurality of adhesive portions 201, at least one adhesive portion 201 being located between adjacent grids 203. In a first direction X, the length of the adhesive portion 201 is a first length L1, and the distance between two grids 203 adjacent to the adhesive portion 201 is a first spacing D1; wherein, L1 / D1≤0.8, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7 or 0.8. Within this range, the length L1 of the adhesive portion 201 can be less than the distance D1 between adjacent fine grids 203. This avoids the adhesive portion 201 from contacting the fine grid 203 due to excessive length L1, thus preventing the insulating adhesive portion 201 from contacting the fine grid 203. This would prevent the current transmission between the electrical connection portion 202 and the fine grid 203 from being affected, resulting in a lower yield of the photovoltaic module. In other words, when the first length L1 and the first spacing D1 are within the above range, the adhesive portion 201 can be prevented from contacting the fine grid 201, resulting in a higher yield of the photovoltaic module.

[0051] In some embodiments, in the first direction X, the distance between the adhesive portion 201 and the fine grid 203 closest to the adhesive portion 201 is a second spacing D2, where D2 ≥ 0.2 mm. For example, 0.2 mm, 0.3 mm, 0.4 mm, or 0.5 mm, etc. Within this range, the second spacing D2 can prevent the current transmission between the electrical connection portion 202 and the fine grid 203 from being affected due to the adhesive portion 201 contacting the fine grid 203, thus avoiding a low yield of the photovoltaic module. In other words, when the second spacing D2 is within the above range, the adhesive portion 201 can be prevented from contacting the fine grid 201, resulting in a higher yield of the photovoltaic module.

[0052] It should be noted that the second spacing D2 is the distance between the adhesive portion 201 and the fine grid 203 closest to the adhesive portion 201. The second spacing D2 refers to the minimum distance between the adhesive portion 201 and the fine grid 203.

[0053] In some embodiments, the width of the electrical connection portion 202 in the second direction Y is a first width W1, wherein 0.18mm ≤ W1 ≤ 0.30mm, for example, 0.18mm, 0.2mm, 0.22mm, 0.24mm, 0.26mm, 0.28mm, or 0.3mm. The width of the electrical connection portion 202 being within the above range ensures good current conduction capability while also saving on the cost of the material used for the electrical connection portion 202.

[0054] Wherein, the first width W1 is the maximum width of the electrical connection portion 202 in the second direction Y.

[0055] In some embodiments, the length of the adhesive portion 201 in the second direction Y is a second length L2, where 1.0 mm ≤ L2 ≤ 2.0 mm, for example, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, or 2 mm. Having the second length L2 within this range avoids situations where the electrical connection portion 202 is slightly offset and cannot contact and bond with the adhesive portion 201 when placed, due to an excessively small second length L2. It also avoids the problem of excessive cost caused by using a large number of adhesive portions 201 if the second length L2 is too large. In other words, having the second length L2 within this range ensures contact and bonding between the electrical connection portion 202 and the adhesive portion 201, while also saving material on the adhesive portion 201.

[0056] In some embodiments, the adhesive portion 201 includes a first sub-adhesive portion 211 and a second sub-adhesive portion 221, which are located on opposite sides of the electrical connection portion 202. The direction of the first sub-adhesive portion 211 toward the second sub-adhesive portion 221 is parallel to the second direction Y. In the second direction Y, the length of the first sub-adhesive portion 211 is a third length L3, and the length of the second sub-adhesive portion 221 is a fourth length L4. The ratio of L3 to L4 can be 2:9 to 9:2, for example, 2:9, 5:9, 8:9, 1:1, 3:2, 5:2, 7:2, or 9:2. The ratio of the third length L3 to the fourth length L4 is within the above range, ensuring that both sides of the electrical connection portion 202 are in contact with the adhesive portion 201, thus providing good adhesion between the adhesive portion 201 and the electrical connection portion 202.

[0057] It should be noted that, ideally, the third length L3 equals the fourth length L4, i.e., L3:L4 = 1. However, in reality, during the fabrication of photovoltaic modules, slight deviations may occur when placing the electrical connection 202, making it difficult for the electrical connection 202 to be precisely positioned in the middle of the adhesive portion 201. Consequently, the third length L3 and the fourth length L4 are not equal. However, if the ratio of the third length L3 to the fourth length L4 is within the aforementioned range, it ensures that both sides of the electrical connection 202 are in contact with the adhesive portion 201, resulting in good adhesion between the adhesive portion 201 and the electrical connection 202. This avoids a situation where a large positional deviation between the electrical connection 202 and the adhesive portion 201 leads to poor contact and thus poor adhesion, ultimately affecting the yield of the photovoltaic module.

[0058] Figure 7 This is another partial cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure. It should be noted that... Figure 7 It is along Figure 4 A cross-sectional view of the electrical connection portion in the extending direction (i.e., the first direction X) of the electrical connection portion. Figure 7 The bonded portion cannot be observed in the cross-sectional view from this perspective.

[0059] refer to Figure 7 In some embodiments, the photovoltaic module further includes: a cell string, an encapsulating film 204, and a cover plate 205. The cell string is formed by connecting multiple cell cells 200. The encapsulating film 204 is used to cover the surface of the cell string. The cover plate 205 is used to cover the surface of the encapsulating film 204 that is away from the cell string. The cell cells 200 are electrically connected in the form of a whole piece or multiple pieces to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel.

[0060] In some embodiments, the solar cell 200 can be a whole cell or a sliced ​​cell, where a sliced ​​cell refers to a cell formed by cutting a complete whole cell. The solar cells 200 are electrically connected in the form of a whole cell or multiple slices to form multiple cell strings, and the multiple cell strings are electrically connected in series and / or parallel.

[0061] In some embodiments, multiple battery strings can be electrically connected via an electrical connection portion 202. Figure 7 This illustration only shows one positional relationship between the battery cells and the electrical connection portion. Specifically, the fine grids 203 of the same polarity on the battery cells 200 are arranged in the same direction, or in other words, the fine grids 203 of each battery cell with a positive polarity are all arranged facing the same side. Thus, the electrical connection portion 202 connects to different sides of two adjacent battery cells 200. In other embodiments, the battery cells can also be arranged with fine grids of different polarities facing the same side, i.e., the electrodes of multiple adjacent battery cells are arranged in the order of first polarity, second polarity, and first polarity again. In this case, the electrical connection portion connects two adjacent battery cells on the same side. The first polarity is either positive or negative, and the second polarity is either positive or negative.

[0062] In some embodiments, the encapsulating film 204 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the battery cell 200, and the second encapsulating layer covers the other of the front or back sides of the battery cell 200. Specifically, at least one of the first encapsulating layer or the second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulating layer or the second encapsulating layer can also be an EP film, EPE film, or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be manufactured by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0063] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module no longer has the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 204.

[0064] In some embodiments, the cover plate 205 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 205 facing the encapsulating film 204 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 205 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0065] In the above-described photovoltaic module embodiment, on a plane perpendicular to the first and second directions, the height of the adhesive portion is a first height H1, and the height of the electrical connection portion is a second height H2. The first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2. The heights of the adhesive portion and the electrical connection portion are within the above range. This avoids the problem of insufficient adhesion between the adhesive portion and the electrical connection portion due to an excessively low adhesive portion height, which could cause the electrical connection portion to shift during the use or fabrication of the photovoltaic module. This improves the yield of the photovoltaic module. It also avoids the problem of excessively high photovoltaic module costs due to excessively high adhesive portion height and the large amount of adhesive used. Furthermore, it avoids the problem of excessive adhesion between the tooling and the adhesive portion after the adhesive portion is formed, which would result in a large adhesive portion usage. This avoids the need for a long time to separate the tooling and the adhesive portion due to a large adhesive force, thus reducing the fabrication time of the photovoltaic module and improving its fabrication efficiency.

[0066] Accordingly, another embodiment of this disclosure also provides a method for preparing a photovoltaic module, which can prepare the photovoltaic module provided in any of the above embodiments. The preparation method of the photovoltaic module provided in another embodiment of this disclosure will be described in detail below. For parts that are the same as or corresponding to the previous embodiment, please refer to the corresponding descriptions of the foregoing embodiments, which will not be repeated in detail below.

[0067] Figure 8 This is a schematic diagram of an initial adhesive portion and an adjacent fine grid provided in an embodiment of this disclosure.

[0068] Reference Figures 4 to 6 as well as Figure 8A method for manufacturing a photovoltaic module may include: providing a plurality of solar cells 200, each solar cell 200 having a plurality of fine grids 203 spaced apart along a first direction X, the fine grids 203 extending along a second direction Y; forming an initial bonding portion 210 on the surface of the solar cells 200; and providing an electrical connection portion 202, the electrical connection portion 202 being disposed on the surface of the solar cells 200 and extending along the first direction X, the electrical connection portion 202 being used for electrical connection with the plurality of fine grids 203, the electrical connection portion 202 being embedded within the initial bonding portion 210, and electrically... The top surface of the connecting portion 202 protrudes from the top surface of the initial adhesive portion 210; the initial adhesive portion 210 is cured to transform the initial adhesive portion 210 into an adhesive portion 201, which is used to fix the electrical connecting portion 202 to the battery cell 200; wherein, on a plane perpendicular to the first direction X and the second direction Y, the height of the adhesive portion 201 is a first height H1, and the height of the electrical connecting portion 202 is a second height H2, and the first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2.

[0069] The initial adhesive portion 210 is used to contact the electrical connection portion 202. The initial adhesive portion 210 is also used to form an adhesive portion 201 after curing. The adhesive portion 201 is used to fix the electrical connection portion 202.

[0070] In some embodiments, forming an initial adhesive portion 210 on the surface of the battery cell 200 may include: providing a screen (not shown) having a plurality of through holes spaced apart; placing the screen on the battery cell 200 such that the plurality of through holes correspond to the areas of the battery cell 200 to which the initial adhesive portion 210 is to be applied; and performing screen printing to dispose of adhesive material in the plurality of through holes to form the initial adhesive portion 210 on the battery cell 200; wherein, in a plane perpendicular to the first direction X and the second direction Y, the height of the screen is a third height H3, 100μm≤H3≤400μm.

[0071] The screen is used to carry the adhesive material. It has through holes through which the adhesive material flows to the corresponding position on the battery cell 200, forming an initial adhesive portion 210. After curing, the initial adhesive portion 210 forms the adhesive portion 201. The height of the screen affects the height of the initial adhesive portion 210, which in turn affects the height of the adhesive portion 201. Therefore, when the height of the screen is within the aforementioned range, the final height H1 of the adhesive portion 201 can satisfy 0.5H2≤H1≤0.8H2, where H2 is the height of the electrical connection portion 202.

[0072] The adhesive material is the material that forms the initial adhesive portion 201. The adhesive material may include acrylic, epoxy resin, or silicone.

[0073] In some embodiments, the thixotropic index Ti of the adhesive material satisfies: 2.4 ≤ Ti ≤ 6. The thixotropic index Ti is the ratio between low-speed viscosity and high-speed viscosity. The thixotropic index Ti can reflect the shape retention of the adhesive material. When the thixotropic index Ti of the adhesive material is within the above range, it can avoid the problem that the adhesive material is difficult to flow out of the mesh to form the initial bond 210 during screen printing due to excessively high shape retention caused by an excessively high thixotropic index Ti. Furthermore, the adhesive material forms the initial adhesive portion 210 through screen printing. Before the initial adhesive portion 210 is cured, its thixotropic index can be equal to the thixotropic index Ti of the adhesive material. If the thixotropic index Ti of the adhesive material is within the aforementioned range, it avoids the initial adhesive portion 210 being too low, resulting in poor shape retention. This would cause the initial adhesive portion 210 to flow along the extension direction of the electrical connection portion 202 and contact the fine grid 203 when the electrical connection portion 202 is placed, thus affecting the current transmission between the electrical connection portion 202 and the fine grid 203 and leading to a lower yield of the photovoltaic module. In other words, if the thixotropic index Ti of the adhesive material is within the aforementioned range, it ensures that the adhesive material can be screen-printed from the through-hole onto the solar cell 200 to form the initial adhesive portion 210, and also ensures that the initial adhesive portion 210 does not extend to contact the fine grid 203 when the electrical connection portion 202 is placed, thereby ensuring the yield of the photovoltaic module.

[0074] Figure 9 This is a partial top view of the mesh of the screen printing plate and the fine grid on the battery cell provided in an embodiment of this disclosure. It should be noted that... Figure 9 This illustration only shows the relationship between a single mesh opening and its adjacent grid lines. In reality, a screen has multiple mesh openings, and a battery has multiple grid lines. Figure 9 This illustration is for informational purposes only and does not represent the intended use of a screen printing plate on a solar cell for screen printing. It does not limit the number of mesh openings or the number of grid lines. Figure 9 The illustrated through-hole is circular, but in reality, through-holes can also be triangular, square, or other shapes.

[0075] Reference Figure 4 , Figure 8 and Figure 9In some embodiments, when the screen is placed on the battery cell 200, the width of the through hole 11 in the first direction X is the third width W3, and the distance between two adjacent fine grids 203 of the through hole 11 is the first spacing D1, satisfying W3 / D1≤0.6, for example, 0.2, 0.3, 0.4, 0.5 or 0.6. The third width W3 of the through hole 11 affects the amount of adhesive material used to form the initial bonding portion 210 using the through hole 11. The ratio of the third width W3 to the first spacing D1 is within the above range, which can ensure that the amount of adhesive material used in the formed initial bonding portion 210 is moderate, which can have a large contact area with the electrical connection portion 202, while also avoiding the initial bonding portion 210 from contacting the fine grids 203 due to excessive amount of adhesive material.

[0076] In some embodiments, in the first direction X, the distance between the center of the through-hole 11 and the adjacent fine grid 203 is a third spacing D3, where D3 ≥ 0.4 mm, for example, 0.4 mm, 0.5 mm, 0.6 mm, or 0.7 mm. Within this range, the initial adhesive portion 210 formed by the adhesive material flowing out of the through-hole 11 can be prevented from contacting the fine grid 203, and the problem of photovoltaic module performance being affected by the contact between the adhesive portion 201 formed by the initial adhesive portion 210 and the fine grid 203 can also be avoided.

[0077] Reference Figure 4 , Figure 6 , Figure 8 and Figure 9 In some embodiments, when the screen is placed on the battery cell 200, the width of the through hole 11 in the first direction X is a third width W3, and the distance between the center of the through hole 11 and the two adjacent fine grids 203 is a first spacing D1. The third width W3 and the first spacing D1 satisfy: 0.3≤W3 / D1≤0.4, for example, 0.3, 0.34, 0.38 or 0.4. The third width W3 of the through hole 11 affects the amount of adhesive material used to form the initial adhesive portion 210. When the ratio of the third width W3 to the first spacing D1 is within the above range, it can ensure that the amount of adhesive material used in the formed initial adhesive portion 210 is moderate, which can have a large contact area with the electrical connection portion 202, while also avoiding the initial adhesive portion 210 from contacting the fine grids 203 due to excessive amount of adhesive material. Furthermore, the third width W3 of the through hole 11 is positively correlated with the length L1 of the adhesive portion 201. When the third width W3 of the through hole 11 is within the above range, the ratio of the length L1 of the adhesive portion 201 formed by the initial adhesive portion 210 to the distance D1 between the two fine grids 203 is: L1 / D1≤0.8.

[0078] Furthermore, in some embodiments, in the first direction X, the distance between the center of the through-hole 11 and the adjacent fine grid 203 is a third spacing D3, where D3 ≥ 0.6 mm, for example, 0.6 mm, 0.7 mm, or 0.8 mm. Within this range, the initial adhesive portion 210 formed by the adhesive material flowing out of the through-hole 11 can be prevented from contacting the fine grid 203, and the problem of photovoltaic module performance being affected by the contact between the adhesive portion 201 formed by the initial adhesive portion 210 and the fine grid 203 can also be avoided.

[0079] Reference Figure 6 and Figure 8 The initial adhesive part 210 is transformed into the adhesive part 201 after curing. The curing methods include UV curing, heat curing, etc.

[0080] In some embodiments, the width of the initial bonding portion 210 in the first direction X is a second width W2; wherein 0.2mm ≤ W2 ≤ 0.5mm, for example 0.2mm, 0.3mm, 0.4mm or 0.5mm. The width of the initial bonding portion 210 within the above range ensures that the initial bonding portion 210 and the electrical connection portion 202 have sufficient contact area, resulting in a larger contact area and greater adhesive force between the finally formed bonding portion 202 and the electrical connection portion 202. This better secures the electrical connection portion 202 and avoids situations where the current transmission between the electrical connection portion 202 and the fine grid 203 is affected due to the initial bonding portion 210 being too wide and contacting the fine grid 203, leading to a lower yield of the photovoltaic module.

[0081] In some embodiments, the distance between the initial adhesive portion 210 and the adjacent fine grid 203 in the first direction X is a fourth distance D4, 0.3mm ≤ D4 ≤ 0.8mm, for example 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm or 0.8mm. Since the distance between the initial adhesive portion 210 and the adjacent fine grid 203 is within this range, the initial adhesive portion 210 and the adhesive portion 201 formed by the curing of the initial adhesive portion 210 do not contact the fine grid 203. This avoids the situation where the current transmission between the fine grid 203 and the electrical connection portion 202 is affected due to the contact between the adhesive portion 201 and the fine grid 203, thus preventing the photovoltaic module performance from being affected.

[0082] refer to Figure 7In some embodiments, the method for manufacturing photovoltaic modules further includes: placing an encapsulating film 204 on the surface of the solar cell 200, and then setting a cover plate 205 on the surface of the encapsulating film 204 away from the solar cell 200, followed by a lamination process to tightly connect the solar cell 200, the electrical connection portion 202, the encapsulating film 204, and the cover plate 205. Typically, a certain temperature is provided during the lamination process. At this temperature, the solar cell 200 and the electrical connection portion 202 achieve an alloy connection, which reduces contact resistance and ensures smooth current transmission between the electrical connection portion 202 and the solar cell 200.

[0083] In the above-described photovoltaic module manufacturing method, the height of the adhesive portion is a first height H1, and the height of the electrical connection portion is a second height H2. The first height H1 and the second height H2 satisfy the condition: 0.5H2≤H1≤0.8H2. In the photovoltaic module provided in this embodiment, the height of the adhesive portion is within the above range. This avoids the problem of insufficient adhesion between the adhesive portion and the electrical connection portion due to an excessively low adhesive portion height, which could lead to positional displacement of the electrical connection portion during the use or manufacturing of the photovoltaic module. This improves the yield of the photovoltaic module. It also avoids the problem of excessively high photovoltaic module costs due to excessively high adhesive portion height, which could result in a large amount of adhesive portion used. Furthermore, it avoids the problem of excessively high adhesive portion height causing contact and excessive adhesive force between the tooling used to place the electrical connection portion and the adhesive portion during placement. This avoids the need for a long time to separate the tooling and the adhesive portion due to the large adhesive force between them, thus reducing the manufacturing time of the photovoltaic module and improving its manufacturing efficiency.

[0084] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A photovoltaic module, characterized in that: include: A plurality of battery cells, each battery cell surface having a plurality of fine grids arranged at intervals along a first direction, and the fine grids extending along a second direction; A bonding portion, the bonding portion being located on the surface of the battery cell; an electrical connection portion, the electrical connection portion being disposed on the surface of the battery cell and extending along the first direction, the electrical connection portion being used to be electrically connected to the plurality of fine grids, wherein the electrical connection portion is embedded in the adhesive portion so that the adhesive portion fixes the electrical connection portion to the battery cell, and a top surface of the electrical connection portion is exposed from a top surface of the adhesive portion; In which, on a plane perpendicular to the first direction and the second direction, the height of the bonding portion is a first height H1, the height of the electrical connection portion is a second height H2, and the first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2.

2. The photovoltaic module according to claim 1, characterized in that: The photovoltaic component includes a plurality of the bonding portions, at least one of the bonding portions is located between adjacent fine grids, in the first direction, the length of the bonding portion is a first length L1, and the distance between two fine grids adjacent to the bonding portion is a first spacing D1; wherein L1 / D1≤0.

8.

3. The photovoltaic module according to claim 2, characterized in that: In the first direction, the distance between the bonding portion and the fine grids adjacent to the bonding portion is a second spacing D2, where D2≥0.2 mm.

4. The photovoltaic module according to claim 2, characterized in that: The length of the bonding portion in the second direction is a second length L2, and 1.0 mm≤L2≤2.0 mm.

5. The photovoltaic module according to claim 4, characterized in that: The bonding portion includes a first sub-bonding portion and a second sub-bonding portion, the first sub-bonding portion and the second sub-bonding portion are located on two opposite sides of the electrical connection portion, and the direction from the first sub-bonding portion to the second sub-bonding portion is parallel to the second direction; In the second direction, the length of the first sub-adhesive portion is a third length L3, the length of the second sub-adhesive portion is a fourth length L4, and L3:L4 is 2:9 to 9:

2.

6. A method for preparing a photovoltaic module, characterized in that: include: Providing a plurality of battery cells, wherein the surface of the battery cells has a plurality of fine grids arranged at intervals along a first direction, and the fine grids extend along a second direction; forming an initial bonding portion on the surface of the battery cell; Providing an electrical connection portion, the electrical connection portion is arranged on the surface of the battery cell and extends along the first direction, the electrical connection portion is used to electrically connect to the plurality of fine grids, the electrical connection portion is embedded in the initial bonding portion, and the top surface of the electrical connection portion is exposed from the top surface of the initial bonding portion; Curing the initial bonding portion to convert the initial bonding portion into a bonding portion, wherein the bonding portion is used to fix the electrical connection portion to the battery cell; In which, on a plane perpendicular to the first direction and the second direction, the height of the bonding portion is a first height H1, the height of the electrical connection portion is a second height H2, and the first height H1 and the second height H2 satisfy: 0.5H2≤H1≤0.8H2.

7. The method for preparing a photovoltaic module according to claim 6, characterized in that: Forming the initial bonding portion on the surface of the battery cell includes: Providing a screen having a plurality of through holes arranged at intervals; Placing the screen on the battery sheet so that the plurality of through holes correspond to the area of ​​the battery sheet where the initial bonding portion needs to be applied; Performing screen printing to place the adhesive material in the plurality of through holes to form the initial adhesive portion on the battery cell; Wherein, on a plane perpendicular to the first direction and the second direction, the height of the screen is a third height H3, and 100 μm≤H3≤400 μm.

8. The method for preparing a photovoltaic module according to claim 7, characterized in that: The thixotropic index Ti of the adhesive material satisfies: 2.4≤Ti≤6.

9. The method for preparing a photovoltaic module according to claim 7, characterized in that: The width of the initial bonding portion in the first direction is a second width W2, wherein 0.2 mm≤W2≤0.5 mm.

10. The method for preparing a photovoltaic module according to claim 7, characterized in that: When the screen is placed on the battery cell, the width of the through hole in the first direction is a third width W3, and the distance between two adjacent fine grids of the through hole is a first spacing D1, satisfying W3 / D1≤0.6.

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