Solar cell and photovoltaic module

Abstract

The utility model provides a solar cell and a photovoltaic assembly, and belongs to the technical field of solar cells. The solar cell includes: a cell body; the plurality of current collection electrodes are arranged on one surface of the battery body, and the plurality of current collection electrodes are alternately arranged at intervals along a first direction with different polarities and extend along a second direction vertical to the first direction; the insulating part covers a partial region of each collector electrode, and the insulating part is provided with a first surface far away from the battery body and a second surface close to the battery body in the thickness direction; the insulating part is provided with first air holes, the first air holes are at least partially exposed to the first surface and / or the second surface, and the number of the first air holes in the unit projection area range of 10 [mu] m * 10 [mu] m of the insulating part on the first surface is 0-10. According to the utility model, few or even no air holes are formed in the insulating part, so that the effectiveness of the insulating part is improved, and the risk of short circuit of the solar cell is avoided.

Description

Technical Field

[0001] This utility model relates to the field of solar cell technology, specifically to a solar cell and a photovoltaic module. Background Technology

[0002] In back-contact (BC) cells, both the positive and negative electrodes are located on the back side of the cell, effectively reducing the shading area of ​​the light-receiving surface and thus improving the light utilization efficiency of the solar cell. This gives back-contact cells higher short-circuit current and photoelectric conversion efficiency, making them one of the main technological directions for achieving high-efficiency crystalline silicon cells.

[0003] BC batteries primarily collect current from sub-grids (collector electrodes) through the main grid. The main grid needs to be electrically connected to the same-polarity sub-grids on the cell and electrically isolated from the opposite-polarity sub-grids. Otherwise, the main grid will conduct and short-circuit with the opposite-polarity sub-grids. To achieve effective isolation between the two, electrical insulating adhesive is usually printed on the part of the opposite-polarity sub-grids near the main grid.

[0004] In related technologies, the printing method results in a large number of pores in the insulating adhesive, which may lead to the main grid becoming conductive with the opposite-shaped sub-grid. Utility Model Content

[0005] In view of the above, in order to at least partially solve at least one of the aforementioned technical problems, the present invention provides a solar cell and a photovoltaic module.

[0006] To achieve the above objectives, the technical solution of this utility model is as follows:

[0007] According to one aspect of the present invention, a solar cell is provided, comprising: a cell body; a plurality of current collector electrodes disposed on a surface of the cell body, the plurality of current collector electrodes being arranged alternately at intervals along a first direction with different polarities and extending along a second direction perpendicular to the first direction; an insulating portion covering a portion of each current collector electrode, the insulating portion having a first surface away from the cell body and a second surface close to the cell body in the thickness direction; the insulating portion having first pores, the first pores being at least partially exposed on the first surface and / or the second surface, the number of the first pores in the insulating portion within a unit projected area of ​​10μm×10μm on the first surface being 0 to 10.

[0008] In some illustrative embodiments, the projection of the first vent onto the surface of the battery body is a pattern formed by arcs.

[0009] In some illustrative embodiments, the size of the first pore along the first direction is 1~10μm, and the size of the first pore along the second direction is 1~10μm.

[0010] In some illustrative embodiments, the insulating portion further includes a second pore formed inside the insulating portion.

[0011] In some illustrative embodiments, the size of the second pore along the first direction is 1~10μm, the size of the second pore along the second direction is 1~10μm; and / or, the number of second pores within a unit projected area of ​​10μm×10μm on the first surface of the insulating portion is 0~10.

[0012] In some illustrative embodiments, the first surface of the insulating portion has an angle greater than 160° with respect to the battery body; the angle is the angle between the tangent of the contact portion between the first surface and the battery body and the battery body.

[0013] In some illustrative embodiments, the roughness of the first surface of the insulating portion is less than 1.6 μm.

[0014] In some illustrative embodiments, when the insulating part has a first pore and / or a second pore, the first pore and / or the second pore shall at least satisfy one of the following conditions: A. The size of the first pore and / or the second pore in the thickness direction does not exceed 4 μm; B. The size of the first pore and / or the second pore in the thickness direction does not exceed 20% of the thickness of the body.

[0015] In some illustrative embodiments, the solar cell further includes: a junction portion that partially covers the area on the current collector electrode other than the insulating portion; the length of the insulating portion along the second direction is greater than or equal to the length of the junction portion along the second direction.

[0016] In some illustrative embodiments, the length of the insulating portion along the second direction is 1 to 15 times the length of the joint portion along the second direction; and / or, the length of the insulating portion along the second direction is 0.9 to 9 mm, and the length of the joint portion along the second direction is 0.6 to 0.9 mm.

[0017] In some illustrative embodiments, the thickness of the insulating portion is less than or equal to 35 μm.

[0018] According to another aspect of the present invention, a photovoltaic module is provided, comprising at least one solar cell as described above.

[0019] In some illustrative embodiments, the photovoltaic module also includes an electrical connection wire, which is electrically connected to the same polarity current collector electrode through a joint, and electrically isolated from the opposite polarity current collector electrode through an insulating portion.

[0020] According to embodiments of this utility model, by forming fewer first pores in the insulating part, the insulating part has better structural integrity and uniformity, which helps to better protect the current collecting electrode, reduce its influence from external environmental factors, prevent direct contact between opposite electrodes or conductive bridging formed through other means (such as moisture, dust, etc.), enhance the insulation performance of the insulating part, reduce the risk of conduction between opposite electrodes, and thus improve the stability and service life of the solar cell. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings of the embodiments will be briefly introduced below. Obviously, the drawings described below only involve some embodiments of this utility model, and are not intended to limit this utility model.

[0022] Figure 1 A partial top view of a solar cell provided in an illustrative embodiment of the present invention is shown;

[0023] Figure 2 A partial cross-sectional view of the insulating portion provided in an embodiment of the present invention is shown;

[0024] Figure 3 A schematic diagram showing the included angle between the insulating part and the battery body provided in an embodiment of the present invention is shown; and

[0025] Figure 4 A scanning electron microscope (SEM) image of the insulating portion of a specific embodiment of the present invention is shown.

[0026] In the accompanying drawings, the meanings of the reference numerals are as follows:

[0027] 1- Battery body;

[0028] 2-Collector;

[0029] 3-Insulation part;

[0030] 31 - First surface;

[0031] 32 - Second surface;

[0032] 33 - First pore;

[0033] 34 - Second pore;

[0034] 4-Electrical connection wires;

[0035] 5-Joint;

[0036] 6-Binding ointment;

[0037] A - Included angle;

[0038] W1 - Length of the insulating portion along the second direction;

[0039] W2 - Length of the joint along the second direction;

[0040] H - Thickness direction. Detailed Implementation

[0041] The embodiments of the present invention will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the present invention.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. The term "comprising" as used herein indicates the presence of features, steps, or operations, but does not exclude the presence or addition of one or more other features.

[0043] When using expressions such as "at least one of A, B, and C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, and C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.). When using expressions such as "at least one of A, B, or C," the expression should generally be interpreted in accordance with the meaning commonly understood by a person skilled in the art (e.g., "a system having at least one of A, B, or C" should include, but is not limited to, systems having A alone, having B alone, having C alone, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0044] In this invention, the relative position between two components (e.g., a membrane or region), referred to as "above," "on," or "above," can mean that the two components are in direct contact or that they are not in direct contact. Similarly, the relative position between two components, referred to as "below," "under," or "below," can mean that the two components are in direct contact or that they are not in direct contact. For example, when one component (e.g., a membrane or region) is referred to as "on another component," it can be directly on the other component, or there may be other components between them. On the other hand, when a component is referred to as "directly on another component," there are no components between them. Furthermore, when one component is referred to as "on another component," the two have a vertical relationship in the planar view, and this component can be above or below the other component, thus this vertical relationship depends on the orientation of the device.

[0045] In related technologies, the insulating adhesive between dissimilar electrodes is often formed by screen printing followed by heat curing. Because thermosetting insulating adhesives contain volatile solvents, the evaporation rate during heat curing is 12-20%, resulting in numerous pores and bubbles on the surface of the cured insulating portion due to solvent evaporation. Scanning electron microscopy (SEM) images of the insulating portion from these technologies show that the insulating portion formed by commonly used screen printing and heat curing has many pores and bubbles, increasing the probability of short circuits between dissimilar electrodes and reducing the stability of the solar cell.

[0046] To address these issues, one approach in related technologies is to increase the printing thickness of the thermosetting insulating adhesive to reduce the risk of short circuits. However, this method results in a larger consumption of insulating adhesive, making it difficult to reduce costs. Furthermore, solvent evaporation causes the thermosetting insulating adhesive to shrink in volume, leading to stress on the solar cell surface due to the shrinkage after curing. This results in significant warping of the solar cell (≥3.5mm), making it more prone to cell breakage and microcracks during subsequent stringing and lamination processes, thus affecting the performance of the solar cell.

[0047] In the process of realizing the concept of this utility model, it was discovered that by using inkjet to coat the insulating adhesive and then performing photocuring treatment, the insulating part of this embodiment has fewer or even no pores, the surface of the prepared insulating part is relatively smooth, the effective insulation thickness of the insulating part is increased, and the insulation effect between opposite electrodes is improved.

[0048] Figure 1 A partial top view of a solar cell provided in an illustrative embodiment of the present invention is shown.

[0049] According to the solar cell provided by this utility model, such as Figure 1 As shown, the solar cell of this utility model can be a back-contact heterojunction (HBC) cell, a TBC (TopCon-Back Contact) cell, or a hybrid HBC cell such as a hybrid cell combining TBC (TopCon-Back Contact) and HJT (Heterojunction with Intrinsic Thin-layer, HJT).

[0050] Furthermore, the solar cell of this invention can be made using, for example... Figure 1 The structure shown is a gridless (OBB) structure. That is, the collector electrode 2 is directly connected to the external electrical connection line 4 by welding without passing through the bus electrode (also called the main grid).

[0051] The aforementioned solar cell includes a cell body 1, which at least includes a substrate and a doped layer on the substrate, wherein the substrate has a rectangular or square structure. The substrate can be, for example, a semiconductor material selected from monocrystalline silicon, polycrystalline silicon, or microcrystalline silicon, and more preferably an N-type or P-type monocrystalline silicon substrate. Cells based on monocrystalline silicon substrates have higher conversion efficiency compared to other types, such as polycrystalline silicon cells. An N-type crystalline silicon substrate is obtained by introducing donor impurities such as group VA elements like phosphorus (P), arsenic (As), or antimony (Sb) into these semiconductor materials, or a P-type crystalline silicon substrate is obtained by introducing acceptor impurities such as group IIIA elements like boron (B), aluminum (Al), or gallium (Ga).

[0052] Solar cells based on any of the above embodiments, Figure 2 A partial cross-sectional view of the insulating portion provided in an embodiment of the present invention is shown, as follows: Figures 1-2 As shown, the aforementioned solar cell includes: a cell body 1, current collector electrodes 2, and an insulating portion 3. Multiple current collector electrodes 2 are disposed on one surface of the cell body 1 (such as the back surface of the cell body 1, i.e., the surface facing away from the light). Figure 2 On the surface shown (facing the viewpoint, and the corresponding other surface being the light-receiving surface), multiple collector electrodes 2 (also called fine grids, collector grid lines, sub-grids, etc.) with different polarities are used to extract majority carriers or minority carriers from different doped regions along a first direction (e.g., ...). Figure 2 The arrangement is alternately spaced in the vertical direction (as shown), and along a second direction perpendicular to the first direction (such as...). Figure 2Extending in the left-right direction (as shown). The insulating portion 3 covers a portion of each current collector electrode 2 to isolate opposite electrodes (e.g., between external electrical connections and opposite polarity current collector electrodes 2). The insulating portion 3 has a first surface 31 away from the battery body 1 and a second surface 32 close to the battery body 1 in the thickness direction H (perpendicular to the protective line of the battery body 1). The insulating portion 3 has first pores 33, which are at least partially exposed on the first surface 31 and / or the second surface 32. The number of first pores 33 on the first surface 31 is 0 to 10, with a unit projected area in the range of 10 μm × 10 μm.

[0053] It should be noted that the insulating part prepared by screen printing followed by thermosetting in the relevant technology results in numerous pores in the insulating part. This is because the insulating adhesive used in screen printing contains a relatively high amount of volatile solvents (12-20%). During the post-printing heat curing process, the slow curing speed causes a significant amount of volatile additives to evaporate, leading to the formation of pores. The presence of pores weakens the insulating performance of the insulating material. The large number or large size of pores in the insulating part prepared by this technology makes them potential current leakage paths, especially when environmental conditions change (e.g., increased humidity), increasing the risk of short circuits between dissimilar electrodes.

[0054] Furthermore, due to the evaporation of volatile solvents, the insulating adhesive will shrink in volume, and the surface of the solar cell will generate stress due to the shrinkage of the insulating adhesive after high-temperature thermosetting, resulting in a cell warpage of greater than or equal to 2.5 mm. The large degree of warpage will cause problems such as cell breakage and microcracks during subsequent stringing and lamination processes, thus affecting the performance of the solar cell module.

[0055] According to an embodiment of this invention, the insulating portion 3 is formed by inkjet coating of an insulating adhesive material followed by photocuring. The resulting insulating portion 3 has fewer first pores 33. Reducing the number of first pores 33 effectively enhances the insulation performance of the insulating portion 3, reduces the risk of accidental conduction between opposite electrodes, and gives the insulating portion 3 better structural integrity and uniformity, which helps to better protect the current collector electrode 2 and enhance the insulation performance of the insulating portion 3. Such an insulating portion 3 can still have good insulation reliability even when it is relatively thin, which can improve the stability of the solar cell while reducing the amount of insulating material used and reducing costs. In addition, since the insulating material used in the inkjet photocuring of this invention has a high solid content, above 95%, preferably above 98%, with little or no volume shrinkage, and the photocuring process has low temperature dependence (for example, the insulating portion 3 can be formed at room temperature), it is beneficial to reduce the warpage of the solar cell and reduce the risk of breakage and microcracks in the solar cell manufacturing process.

[0056] It should be noted that, unless otherwise specified, “thickness” generally refers to the dimension along the direction perpendicular to the surface of the battery body 1.

[0057] It should be noted that "inkjet coating" can be understood as using inkjet printing to precisely deposit insulating material in the form of tiny droplets onto a portion of the solar cell to form the insulating part 3. Photocuring can be understood as using a photosensitive insulating material that undergoes a chemical reaction when exposed to light of a certain wavelength, thereby forming a robust insulating part 3. This photosensitive insulating material can be, for example, an insulating material with a solid content of over 95%, containing almost no volatile solvents or other small molecules, enabling rapid curing and shaping of the insulating material, and avoiding the stirring and repetitive printing processes found in related technologies, further reducing the formation of the first pore 33.

[0058] In one illustrative embodiment, taking an n-type silicon substrate as an example, the first polarity current collector 2 is disposed on the n-type doped region, and the second polarity current collector 2 is disposed on the p-type doped region.

[0059] In some optional embodiments, the number of first pores 33 within a unit projected area of ​​10μm × 10μm on the first surface 31 of the insulating portion 3 is 0 to 10. This can be understood as using a unit projected area of ​​10μm × 10μm on the first surface 31 as a counting benchmark, the number of first pores 33 exposed on the first surface 31 and / or the second surface 32 within a unit projected area of ​​the insulating portion 3 is 0 to 10, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. As described above, this arrangement helps to reduce the possibility of contact between dissimilar electrodes through the insulating portion 3, thereby reducing the probability of short circuits and improving the stability of the solar cell.

[0060] Optionally, the number of first pores 33 within a unit projected area of ​​10μm×10μm on the first surface 31 of the insulating part 3 is 0, further improving the reliability of the insulation.

[0061] In some alternative embodiments, the current collector 2 may be selected from metals (e.g., Ag, Cu, Al, Ni, Au, Zn, Sn, Pb, silver-clad copper, etc.), conductive metal oxides (various TCOs, such as ITO, AZO, IWO, etc.), metal nitrides (TiN, etc.), metal carbides (TiC, etc.), or metal sulfides, as well as other conductive connecting materials (e.g., graphene, etc.), or various combinations of the above materials.

[0062] Furthermore, the current collector 2 can be a metal electrode, manufactured by methods such as printing or electrodeposition. Optionally, a metal paste can be printed onto the battery body 1, and then the metal paste can be sintered to achieve metallization. The printing method can be, for example, screen printing or inkjet printing, and more preferably, the lower-cost screen printing method.

[0063] In some illustrative embodiments, the projection of the first vent 33 onto the surface of the battery body 1 is a pattern formed by arcs. "A pattern formed by arcs" means that the projection of the first vent 33 onto the surface of the battery body 1 does not have sharp edges or points, but rather is a pattern formed by smooth curves of a certain shape. This is to alleviate potential stress concentration between the first vent 33 and the battery body 1 when the first vent 33 is exposed to the contact surface of the first surface 31. Preferably, the pattern is circular or elliptical.

[0064] In some illustrative embodiments, the size of the first pore 33 along the first direction is 1~10μm, for example, it can be 1μm, 3μm, 5μm, 7μm or 9μm. The size of the first pore 33 along the second direction is 1~10μm, for example, it can be 1μm, 3μm, 5μm, 7μm or 9μm. The size of the first pore 33 within the above range helps to reduce the possibility of contact between opposite electrodes (e.g., between opposite polarity collector electrode 2 and main gate (or electrical connection line)), thereby further reducing the risk of short circuit between them.

[0065] In some illustrative embodiments, references Figure 3 The insulating part 3 also includes a second vent 34, which is formed inside the insulating part 3. Wherein, the distribution of the second vent 34 inside the insulating part 3 requires that two second vents 34 do not overlap, or when two second vents 34 overlap to form a large vent, they are counted as one second vent 34.

[0066] It should be noted that related technologies, which use screen printing followed by thermosetting, require the insulating adhesive to maintain a certain viscosity and thixotropic properties during the printing process. This makes it relatively easy for gas to be introduced during stirring and printing, resulting in second pores 34 (which can be understood as air bubbles forming inside the insulating part 3). In contrast, the insulating part 3 of this invention can achieve rapid curing and shaping of the insulating material through photocuring. It can be understood that the insulating material of this invention has lower viscosity and higher solids content, resulting in stronger defoaming ability. Furthermore, it avoids the generation of second pores 34 through stirring and repeated printing, further enhancing the insulating performance of the insulating part 3, reducing the risk of accidental conduction between dissimilar electrodes, and also contributing to better structural integrity and uniformity of the insulating part 3.

[0067] In some illustrative embodiments, the size of the second pore 34 along the first direction is 1~10μm, such as... Figure 3 As shown, the size of the second pore 34 along the second direction can be, for example, 1μm, 3μm, 5μm, 7μm, or 9μm. The size of the second pore 34 along the second direction is 1~10μm, for example, 1μm, 3μm, 5μm, 7μm, or 9μm. And / or, the number of second pores 34 on the first surface 31 of the insulating part 3 within a unit projected area of ​​10μm×10μm is 0~10. This can be understood as, taking the unit projected area of ​​the insulating part on the first surface 31 of 10μm×10μm as the counting benchmark, the number of second pores 34 located inside the insulating part 3 within a unit projected area is 0~10, for example, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10. As described above, by further adjusting the number and size of the second vent 34, the adverse effects on the insulation performance of the insulating part 3 are minimized, the possibility of contact between opposite electrodes is reduced, the probability of short circuit is reduced, and a certain light trapping effect can be achieved.

[0068] In some illustrative embodiments, such as Figure 3 As shown, the first surface 31 of the insulating part 3 has an included angle A with the battery body 1. Here, the included angle A is the included angle A of the outer side of the insulating part 3, and the included angle A is greater than 160°, for example, it can be 161°, 163°, 165°, 168°, 170°, 175° or 180°, etc. It can be understood that the included angle A is the angle between the tangent of the contact part between the first surface 31 and the battery body 1 and the battery body 1.

[0069] It should be noted that when coating insulating materials using inkjet printing, the insulating material is relatively thin. This is understandable because, although the solid content of the insulating material is over 95%, its low viscosity prevents nozzle clogging, making the process easier. Therefore, the included angle A is larger than that of conventional screen printing methods. A larger included angle A means that less insulating material can be used to coat a larger area of ​​the current collector electrode 2, which helps reduce the amount of insulating material used and further thins the insulating part 3, thereby reducing costs.

[0070] Further optionally, the included angle A is 161~165°, for example, it can be 161°, 162°, 163°, 164°, 165°, etc. When the included angle A is adjusted within the above range, it can ensure good fluidity of the insulating material, ensure the inkjet printing process, and avoid the insulating material being too thin, causing it to overflow from the fixed preset position, thereby achieving a better insulation effect.

[0071] In some illustrative embodiments, the roughness Rz of the first surface 31 of the insulating portion 3 is less than 1.6 μm, for example, it can be 1.0 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm or 1.5 μm, etc.

[0072] For example, for quantitative measurement of surface roughness, the cross-sectional profile of the surface of the first pore 33 can be obtained by optical sectioning or interferometry, and then evaluated based on the two indices Ra and Rz. The surface roughness Ra can be the arithmetic mean deviation of the profile. , where |y i | represents the absolute distance from each point on the actual surface profile within the sampling length to the profile centerline, and n represents the number of points on the actual surface profile within the sampling length. Surface roughness Rz is the ten-point average height of micro-irregularities, which is the sum of the average height of the five largest profile peaks and the average depth of the five largest profile valleys within the sampling length. Generally, Rz is approximately equal to 5 × Ra.

[0073] In related technologies, screen printing results in a high surface roughness due to numerous air bubbles and pores on the surface and inside the insulating portion. This leads to a greater defect depth between the bottom of the air bubbles and the surface of the insulating portion, resulting in a smaller effective insulation thickness for the same coating thickness. In contrast, the insulating portion 3 of this invention is formed by inkjet printing followed by photocuring, resulting in a smoother first surface 31 with lower roughness and virtually no first air bubbles 33 and / or second air bubbles 34. Therefore, for the same coating thickness, the insulating portion 3 of this invention has a greater effective insulation thickness, indicating higher reliability of the inkjet photocuring method.

[0074] Furthermore, while maintaining the same short-circuit yield of the insulation part 3, the insulation part 3 of this invention can use a smaller coating thickness, thereby reducing the cost of using insulation materials.

[0075] In some illustrative embodiments, when the insulating portion 3 has a first pore 33 and / or a second pore 34, the first pore 33 and / or the second pore 34 satisfy at least one of the following conditions: A. The size of the first pore 33 and / or the second pore 34 in the thickness direction H does not exceed 4 μm, for example, it can be 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, etc.; B. The size of the first pore 33 and / or the second pore 34 in the thickness direction H does not exceed 20% of the thickness of the insulating portion 3, for example, it can be 1%, 5%, 10%, 15%, or 20%, etc. With this configuration, since the number of first pores 33 and second pores 34 is small and the size satisfies the above conditions, the effective insulation effect of the insulating portion 3 can be satisfied, thus meeting the insulation requirements.

[0076] In some illustrative embodiments, the solar cell further includes: a bonding portion 5, which partially covers the area on the current collector electrode 2 other than the insulating portion 3; the bonding portion 5 may be, for example, a pad, on which bonding paste 6 (e.g., solder, solder paste, or conductive adhesive layer, such as conductive silver paste, conductive glue, etc.) is applied to bond the current collector electrode 2 to the electrical connection line 4 of the same polarity through the bonding portion 5 and the bonding paste 6, so that the current collector electrode 2 and the electrical connection line 4 of the same polarity present a good connection relationship.

[0077] Alternatively, the solar cell may not include the bonding paste 6, and the bonding portion 5 can be understood as directly connecting the current collector 2 to the electrical connection line 4 of the same polarity through the bonding portion 5.

[0078] In some illustrative embodiments, the solar cell may further include: a bus electrode (not shown in the figure), which is directly contacted and electrically connected to the current collector 2 of the same polarity, and electrically isolated from the current collector 2 of a different polarity. The bus electrode can be considered as the main grid structure connecting the current collector 2. The bus electrode is pre-positioned at a specific location on the cell body 1. During the welding process of the bus electrode to the electrical connection line 2, the electrical connection line 2 has a bonding portion 5. The bonding portion 5 melts and joins with the bus electrode and dissolves to form an intermetallic compound (i.e., IMC). It can be understood that the bus electrode is disposed on the side of the bonding portion 5 closer to the cell body 1, and is electrically connected to the external electrical connection line 4 through the bonding portion 5.

[0079] In one illustrative embodiment, the material of the bus electrode includes, but is not limited to, silver, copper, and silver-plated copper.

[0080] In some illustrative embodiments, the length W1 of the insulating portion 3 along the second direction is greater than or equal to the length W2 of the connecting portion 5 along the second direction. This arrangement helps to further prevent contact between the current collectors 2 of opposite polarities, thereby enhancing the insulation effect of the insulating portion 3.

[0081] Optionally, the length W1 of the insulating part 3 along the second direction is 1 to 15 times the length W2 of the connecting part 5 along the second direction, for example, it can be 1, 3, 5, 7, 10, 13 or 15 times.

[0082] Further optionally, the length W1 of the insulating portion 3 along the second direction is 0.9 to 9 mm, for example, it can be 0.9 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm or 9 mm, etc.; the length W2 of the connecting portion 5 along the second direction is 0.6 to 0.9 mm, for example, it can be 0.6 mm, 0.65 mm, 0.7 mm, 0.75 mm, 0.8 mm, 0.85 mm or 0.9 mm, etc.

[0083] In some illustrative embodiments, the width of the insulating portion 3 along the first direction is 0.1~0.5mm, for example, it can be 0.1mm, 0.105mm, 0.205mm, 0.305mm, 0.405mm, 0.495mm or 0.5mm, etc.

[0084] In some illustrative embodiments, the thickness of the insulating part 3 is less than or equal to 35 μm, for example, it can be 13 μm, 14 μm, 17 μm, 19 μm, 22 μm, 24 μm, 28 μm, 33 μm or 35 μm, etc. Since the present invention forms the insulating part 3 by using inkjet coating of insulating adhesive material and then photocuring, the prepared insulating part 3 has fewer first pores 33 and second pores 34. Therefore, the insulating part 3 is relatively dense and its insulation performance is enhanced. Thus, the thickness of the insulating part 3 can be reduced while maintaining good insulation reliability. This can improve the stability of solar cells while reducing the amount of insulating material used and lowering costs.

[0085] In some illustrative embodiments, the length of the bonding paste 6 along the second direction can be less than or equal to the length W2 of the bonding portion 5 along the second direction, and greater than or equal to the width of the electrical connection line 4 along the second direction. This configuration ensures a good connection yield between the electrical connection line 4 and the collector electrode 2 of the same polarity, while avoiding the risk of short circuits caused by the overflow of the bonding paste 6.

[0086] Optionally, the length of the adhesive paste 6 along the second direction is 0.6~0.9mm, for example, it can be 0.6mm, 0.65mm, 0.7mm, 0.75mm, 0.8mm, 0.85mm or 0.9mm, etc.

[0087] Optionally, the insulating material used in the insulating part 3 can be transparent to reduce the light loss that the insulating material may cause.

[0088] It should be noted that multiple insulating parts 3 are discretely distributed on the current collector electrodes 2 of different polarities.

[0089] According to another embodiment of the present invention, a photovoltaic module is provided, comprising at least one solar cell as described above.

[0090] According to an embodiment of the present invention, the above-mentioned solar cells are connected in series to form a solar cell string; and an encapsulation structure is disposed around the outer periphery of the solar cell string.

[0091] According to embodiments of this utility model, the number of solar cells connected in series can be as many as possible, without particular limitation, for example, 4 to 20. Multiple solar cells can form several battery modules, each module containing the same number of solar cells. The cells within a module are connected in series, and the modules can be connected in series or in parallel. The modules are connected by busbars on both sides of the electrical connection layer. The multiple rows of electrical connection lines 4 of the cells within a module are either correspondingly connected or integrated. The spacing between two adjacent battery modules can be 0.5 to 10 mm, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.; the spacing between two adjacent cells within each battery module can also be 0.5 to 10 mm, for example, 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.

[0092] According to embodiments of this utility model, the encapsulation structure may include a backplate, an encapsulating film, a glass panel, etc., to improve the stability of the solar cell string. The glass panel is located on the front of the solar cell string, and the backplate is located on the back of the solar cell string, both serving a protective function. The adhesive film is an adhesive film between the solar cell string and the glass panel and backplate, serving a bonding and fixing function, and must be made of a transparent material.

[0093] In some illustrative embodiments, the photovoltaic module further includes an electrical connection line 4, which is electrically connected to the same polarity current collector 2 through a joint 5, and electrically isolated from the opposite polarity current collector 2 through an insulating part 3.

[0094] By providing the connecting portion 5 between the electrical connection line 4 and the same-polarity current collector 2, the connection yield between the electrical connection line 4 and the same-polarity current collector 2 is improved; by providing the insulating portion 3 between the electrical connection line 4 and the opposite-polarity current collector 2, the insulation effect between the two is enhanced. The shape of the insulating portion 3 can be, for example, block-shaped or strip-shaped, and is not particularly limited here. The length W1 of the insulating portion 3 along the second direction is configured to be greater than or equal to the length W2 of the connecting portion 5 along the second direction, so that electrical isolation between the connecting portion 5 and the current collector 2 of different polarities is ensured.

[0095] Optionally, the width of the electrical connection wire 4 along the second direction can be 0.6 mm.

[0096] In some illustrative embodiments, the insulating portions 3 on both sides of the electrical connection line 4 are symmetrically arranged in a direction perpendicular to the electrical connection line 4, thereby electrically isolating the opposite electrodes on both sides of the electrical connection line 4.

[0097] In one specific embodiment of this utility model, a battery cell printed with positive and negative current collector electrodes is placed on a base, and insulating adhesive is sprayed through a nozzle according to a preset pattern; pre-curing is performed by irradiation with ultraviolet light; and secondary curing is performed by irradiation with ultraviolet light again to achieve the preparation of the insulating part 3. Figure 4 A scanning electron microscope (SEM) image of the insulating portion of a specific embodiment of the present invention is shown. For example... Figure 4 As shown, it can be seen that the surface of the insulating part 3 obtained by inkjet printing followed by photocuring has almost no pores or bubbles, is relatively smooth, and has a good effective insulation thickness.

[0098] It should be noted that the "pores" mentioned in this utility model refer to pores with a size greater than or equal to 1 μm along the first direction and a size greater than or equal to 1 μm along the second direction. For example, the first pore 33 has a size greater than or equal to 1 μm along the first direction and a size greater than or equal to 1 μm along the second direction; the second pore 34 has a size greater than or equal to 1 μm along the first direction and a size greater than or equal to 1 μm along the second direction.

[0099] It should also be noted that the directional terms mentioned in the embodiments, such as "up," "down," "front," "back," "left," and "right," are only for reference in the accompanying drawings and are not intended to limit the scope of protection of this utility model. Throughout the drawings, the same elements are represented by the same or similar reference numerals. Conventional structures or constructions will be omitted where they may cause confusion in understanding this utility model.

[0100] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A solar cell, characterized in that, include: Battery body; Multiple current collectors are disposed on one surface of the battery body. The multiple current collectors are arranged alternately at intervals along a first direction with different polarities and extend along a second direction perpendicular to the first direction. An insulating portion covers a portion of each of the current collector electrodes, the insulating portion having a first surface away from the battery body and a second surface close to the battery body in the thickness direction; The insulating portion has a first pore, which is at least partially exposed on the first surface and / or the second surface. The number of the first pores in the insulating portion within a unit projected area of ​​10 μm × 10 μm on the first surface is 0 to 10.

2. The solar cell according to claim 1, characterized in that, The projection of the first pore onto the surface of the battery body is a pattern formed by an arc.

3. The solar cell according to claim 2, characterized in that, The size of the first pore along the first direction is 1~10μm, and the size of the first pore along the second direction is 1~10μm.

4. The solar cell according to any one of claims 1 to 3, characterized in that, The insulating portion further includes a second pore, which is formed inside the insulating portion.

5. The solar cell according to claim 4, characterized in that, The second pore has a size of 1~10 μm along the first direction, and the second pore has a size of 1~10 μm along the second direction; and / or, The number of second pores in the insulating part within a unit projected area of ​​10μm×10μm on the first surface is 0 to 10.

6. The solar cell according to any one of claims 1 to 3, characterized in that, The first surface of the insulating part has an angle with the battery body, the angle being greater than 160°; The included angle is the angle between the tangent of the contact portion between the first surface and the battery body and the battery body.

7. The solar cell according to any one of claims 1 to 3, characterized in that, The roughness of the first surface of the insulating part is less than 1.6 μm.

8. The solar cell according to claim 4, characterized in that, When the insulating portion has a first pore and / or a second pore, the first pore and / or the second pore at least satisfy one of the following conditions: A. The size of the first pore and / or the second pore in the thickness direction does not exceed 4 μm; B. The size of the first pore and / or the second pore in the thickness direction does not exceed 20% of the thickness of the insulating portion.

9. The solar cell according to any one of claims 1 to 3, characterized in that, The solar cell further includes: a junction portion that partially covers the area outside the insulating portion on the current collector electrode; The length of the insulating portion along the second direction is greater than or equal to the length of the joint portion along the second direction.

10. The solar cell according to claim 9, characterized in that, The length of the insulating portion along the second direction is 1 to 15 times the length of the joint portion along the second direction; and / or, The length of the insulating part along the second direction is 0.9~9mm, and the length of the joint part along the second direction is 0.6~0.9mm.

11. The solar cell according to any one of claims 1 to 3, characterized in that, The thickness of the insulating part is less than or equal to 35 μm.

12. A photovoltaic module, characterized in that, It includes at least one solar cell as described in any one of claims 1 to 11.

13. The photovoltaic module according to claim 12, characterized in that, The photovoltaic module also includes an electrical connection wire, which is electrically connected to the same polarity current collector electrode through a joint, and electrically isolated from the opposite polarity current collector electrode through an insulating part.

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