Solar cell and photovoltaic module

Abstract

The embodiment of the utility model relates to the field of photovoltaic technology, and provides a solar cell and a photovoltaic module, and the solar cell comprises a substrate which is provided with a first surface and a second surface which are opposite to each other; the fine grids are arranged on the first surface at intervals in the first direction, and the fine grids extend in the second direction; the plurality of main grids are arranged on the first surface at intervals along the second direction, extend along the first direction, are electrically connected with the fine grids, comprise a plurality of connecting parts arranged at intervals along the first direction, and further comprise welding parts for connecting the adjacent connecting parts; the top surface of the welding part protrudes in the direction away from the first surface relative to the top surface of the connecting part, and in the thickness direction of the substrate, the difference value between the top surface of the welding part and the top surface of the connecting part is 2-10 [mu] m. The embodiment of the utility model at least can improve the performance of the solar cell.

Description

TECHNICAL FIELD

[0001] The embodiment of the present disclosure relates to the technical field of photovoltaic, in particular to a solar cell and a photovoltaic module. BACKGROUND

[0002] Energy saving is a topic of great concern in today's society, and the development and use of new environmentally friendly clean energy can greatly help the global energy shortage. Solar energy is the most abundant energy in the world, and the use of efficient and stable solar cells can greatly alleviate the global energy crisis. In the future of science and technology development and production and life, solar cells will play an increasingly important role.

[0003] The surface of the solar cell is provided with a main grid, which is used to collect the carriers generated by the solar cell and transmit the carriers to the solder strip. CONTENT OF THE INVENTION

[0004] The embodiment of the present disclosure provides a solar cell and a photovoltaic module, which can at least improve the performance of the solar cell.

[0005] According to some embodiments of the present disclosure, the embodiment of the present disclosure provides a solar cell, comprising: a substrate, the substrate has opposite first and second surfaces; a plurality of thin grids, the plurality of thin grids are arranged along a first direction on the first surface, and the thin grids extend along a second direction; a plurality of main grids, the plurality of main grids are arranged along the second direction on the first surface, and the main grids extend along the first direction, the main grids are electrically connected with the thin grids, the main grids comprise a plurality of connection portions arranged along the first direction, and the main grids further comprise a welding portion connecting adjacent connection portions, a top surface of the welding portion is convex in a direction away from the first surface compared with a top surface of the connection portion, and a difference between the top surface of the welding portion and the top surface of the connection portion in a thickness direction of the substrate is 2-10 μm.

[0006] In some embodiments, the difference between the top surface of the welding portion and the top surface of the connection portion is 3-6 μm.

[0007] In some embodiments, a distance between adjacent welding portions along the first direction is 0.5-2.5 mm.

[0008] In some embodiments, a length of the welding portion along the first direction is 0.2-2 mm.

[0009] In some embodiments, each thin grid is electrically connected with the main grid through the welding portion.

[0010] In some embodiments, the distance between adjacent fine grids in the first direction is 0.7mm-1.2mm.

[0011] In some embodiments, the welding part is connected with a plurality of fine grids, the connecting part is connected with a plurality of fine grids, and the distance between adjacent fine grids connected with the welding part in the first direction is less than the distance between adjacent fine grids connected with the connecting part.

[0012] In some embodiments, the distance between adjacent fine grids connected with the welding part in the first direction is 0.6mm-1.0mm, and the distance between adjacent fine grids connected with the connecting part in the first direction is 1.0mm-3.0mm.

[0013] In some embodiments, the width of the connecting part in the second direction is less than or equal to the width of the welding part.

[0014] According to some embodiments of the present disclosure, the present disclosure provides a photovoltaic module in one aspect, which includes a cell string connected by a plurality of solar cells according to the above embodiments, a solder strip for connecting adjacent solar cells and electrically contacting the welding part, an encapsulation film for covering the surface of the cell string, and a cover plate for covering the surface of the encapsulation film away from the cell string.

[0015] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0016] In the technical solutions of the solar cell provided by the embodiments of the present disclosure, the solar cell includes a substrate having opposite first and second surfaces, a plurality of fine grids spaced apart along a first direction on the first surface and extending along a second direction, and a plurality of main grids spaced apart along the second direction on the first surface and extending along the first direction, the main grids are electrically connected with the fine grids, the main grids include a plurality of connecting parts spaced apart along the first direction, and the main grids further include a welding part connecting adjacent connecting parts, the top surface of the welding part is convex toward a direction away from the first surface compared to the top surface of the connecting part, and the difference between the top surface of the welding part and the top surface of the connecting part in the thickness direction of the substrate is 2um-10um.

[0017] The main grid includes the connecting part and the welding part, when the solder strip is connected with the main grid, the solder strip can be electrically connected with the main grid through the welding part, so that no additional soldering point needs to be arranged on the main grid, and the problem of blocking the light absorption of the solar cell caused by the arrangement of the soldering point can be avoided, so that the solar cell can absorb more sunlight, thereby improving the performance of the solar cell.

[0018] The top surface of the welding portion protrudes in a direction away from the first surface compared to the top surface of the connecting portion, i.e., the thickness of the welding portion is thicker than that of the connecting portion, which can increase the contact area of the welding portion and the solder ribbon, provide good connection reliability for the connection of the main grid and the solder ribbon, and the thicker welding portion can have a smaller resistance, which can reduce the loss in the current transmission process, thereby improving the current collection capability of the welding portion and further improving the performance of the solar cell. The difference between the top surface of the welding portion and the top surface of the connecting portion in the thickness direction of the substrate is 2-10 um. The difference in the above range makes the welding portion have good current collection capability, can provide good connection reliability for the connection of the main grid and the solder ribbon, and can also avoid affecting the light absorption of the solar cell due to the excessive thickness of the welding portion, thereby improving the performance of the solar cell.

[0019] In addition, the main grid is not provided with a fishing rod structure near the edge of the solar cell, which can avoid the problem of blocking the light absorption of the solar cell caused by the fishing rod structure, so that the solar cell can absorb more sunlight, thereby improving the performance of the solar cell. BRIEF DESCRIPTION OF DRAWINGS

[0020] One or more embodiments are illustrated by way of example in the drawings that are for illustrative purposes only, and not for the purposes of limiting the embodiments, unless otherwise specifically stated in the description. None of these drawings is necessarily to scale, except if specifically indicated. Like reference numerals in the drawings and description below indicate like elements unless otherwise expressly recited herein. As will be realized, the embodiments are capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present disclosure. Accordingly, the drawings and descriptions are to be regarded as illustrative in nature, and explanations in the following description are to be taken in a manner most likely to convey the substance of the present embodiments to others skilled in the art.

[0021] Figure 1 A top view of a solar cell provided by an embodiment of the present disclosure;

[0022] Figure 2 A sectional view of a solar cell provided by an embodiment of the present disclosure;

[0023] Figure 3 Another top view of a solar cell provided by an embodiment of the present disclosure;

[0024] Figure 4 A partial three-dimensional structural schematic view of a photovoltaic module provided by an embodiment of the present disclosure;

[0025] Figure 5 A Figure 4 A sectional view in the cross-sectional direction M1M2. DETAILED DESCRIPTION

[0026] In the related art, a soldering point is usually arranged on the main grid to electrically connect and the solder strip. The arrangement of the soldering point will block the solar cell and affect the light absorption of the solar cell, thereby reducing the performance of the solar cell.

[0027] In addition, in the related art, the end of the main grid close to the edge of the cell is arranged in a fishing rod structure. This fishing rod structure also blocks the solar cell and affects the light absorption of the solar cell, thereby reducing the performance of the solar cell.

[0028] In summary, the performance of the solar cell in the related art needs to be improved.

[0029] The solar cell provided by the embodiments of the present disclosure has the following advantages. On the one hand, the main grid includes a connecting portion and a soldering portion. When the main grid and the solder strip are connected, the solder strip can be electrically connected to the main grid through the soldering portion, so that no additional soldering point needs to be arranged on the main grid, and the problem of blocking the light absorption of the solar cell caused by the arrangement of the soldering point can be avoided. On the other hand, the main grid does not have a fishing rod structure close to the edge of the solar cell, so that the problem of blocking the light absorption of the solar cell caused by the arrangement of the fishing rod structure can be avoided. The above two aspects enable the solar cell to absorb more sunlight, thereby improving the performance of the solar cell.

[0030] In addition, the top surface of the soldering portion protrudes in a direction away from the first surface compared to the top surface of the connecting portion, that is, the thickness of the soldering portion is thicker than that of the connecting portion. The contact area of the soldering portion and the solder strip can be increased, the connection reliability of the connection between the main grid and the solder strip can be ensured, the thicker soldering portion can have a smaller resistance, the loss in the current transmission process can be reduced, the current collection capability of the soldering portion can be improved, and the performance of the solar cell can be improved. In the thickness direction of the substrate, the difference between the top surface of the soldering portion and the top surface of the connecting portion is 2 μm to 10 μm. The difference in the above range enables the soldering portion to have good current collection capability, ensures the connection reliability of the connection between the main grid and the solder strip, avoids affecting the light absorption of the solar cell due to the excessive thickness of the soldering portion, and improves the performance of the solar cell.

[0031] In the description of the embodiments of the present disclosure, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly specified.

[0032] Reference to“an embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase“in an embodiment” in various places in the specification are not necessarily referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly contemplated that embodiments described herein can be combined with each other, even though some embodiments are not specifically mentioned or illustrated herein.

[0033] In the description of the embodiments of the disclosure, the term“and / or” only means an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean that A exists, A and B exist at the same time, and B exists. In addition, the character“ / ” herein generally means that the front and rear associated objects are in an“or” relationship.

[0034] In the description of the embodiments of the disclosure, the term“a plurality of” refers to two or more (including two), and similarly, “a plurality of groups” refers to two or more groups (including two groups), and “a plurality of pieces” refers to two or more pieces (including two pieces).

[0035] In the description of the embodiments of the disclosure, the technical terms“center”,“longitudinal”,“transverse”,“length”,“width”,“thickness”,“upper”,“lower”,“front”,“rear”,“left”,“right”,“vertical”,“horizontal”,“top”,“bottom”,“inner”,“outer”,“clockwise”,“counterclockwise”,“axial”,“radial”,“circumferential” and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the disclosure.

[0036] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical terms“mounting”,“connection”,“connection”,“fixing” and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the disclosure can be understood according to the specific circumstances.

[0037] In the drawings corresponding to the embodiments of the present disclosure, the thickness and area of a layer are exaggerated for clarity. When it is described that one component (such as a layer, film, region, or substrate) is on or is at the surface of another component, the component can be "directly" on the surface of the other component, or a third component can be present between the two components. Conversely, when it is described that one component is on the surface of another component, or one component surface forms or is provided with another component, it means that there is no third component between the two components. In addition, when it is described that one component is "approximately" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0038] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components can be further included. In addition, when a layer, film, region, or plate, etc. component is referred to as "on / over" another component, it can be "directly on" another component (i.e. between the surface of another component and another component, there is no other component), or another component can be present therebetween. In addition, when a layer, film, region, plate, etc. component is "directly on" another component, or when a layer, film, region, plate, etc. component is on the surface of another component, it means that there is no other component therebetween.

[0039] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented in order to make the reader better understand the present disclosure. However, the technical solutions claimed by the present disclosure can be implemented even without these technical details and based on various changes and modifications of the following embodiments.

[0040] Figure 1 A top view of a solar cell provided by an embodiment of the present disclosure, Figure 2 A cross-sectional view of a solar cell provided by an embodiment of the present disclosure.

[0041] Combined with reference Figure 1 and Figure 2The solar cell includes a substrate 100, a plurality of fine grids 101, and a plurality of main grids 102. The substrate 100 has a first face 110 and a second face 120 opposite to each other. The plurality of fine grids 101 are arranged in a first direction X on the first face 110, and the fine grids 101 extend in a second direction Y. The plurality of main grids 102 are arranged in the second direction Y on the first face 110, and the main grids 102 extend in the first direction X. The main grids 102 are electrically connected to the fine grids 101. The main grids 102 include a plurality of connection portions 112 arranged in the first direction X. The main grids 102 further include a welding portion 122 connecting adjacent connection portions 112. A top face of the welding portion 122 is convex in a direction away from the first face 110 compared to a top face of the connection portion 112. In a thickness direction of the substrate 100, a difference between the top face of the welding portion 122 and the top face of the connection portion 112 is 2-10 μm.

[0042] It can be understood that, Figure 2 It can be understood that,

[0043] The solar cell is used to absorb sunlight and convert light energy into electrical energy.

[0044] In some embodiments, the solar cell includes one or any combination of a PERC (Passivated Emitter Rear Cell) cell, an IBC (Interdigitated Back Contact) cell, a TOPCon (Tunnel Oxide Passivated Contact) cell, an HIT / HJT (Heterojunction Technology) cell, a thin-film solar cell, and a stacked cell. The thin-film solar cell includes, but is not limited to, a perovskite thin-film solar cell, a copper-indium-selenium thin-film solar cell, a gallium-arsenide thin-film solar cell, and a cadmium-sulfide thin-film solar cell. The stacked cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin-film cell.

[0045] In some examples, the substrate 100 can be a silicon substrate, specifically a single-crystal silicon substrate or a polycrystalline silicon substrate of N type or P type.

[0046] The substrate 100 is configured to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 can be a semiconductor substrate.

[0047] In some embodiments, the material of the substrate 100 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, for example, can be silicon or germanium. Among them, the elemental semiconductor material can be single-crystalline, polycrystalline, amorphous or microcrystalline (a state having both single-crystalline and amorphous, referred to as microcrystalline), for example, silicon can be at least one of single-crystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon.

[0048] In some embodiments, the material of the substrate 100 can also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium and the like.

[0049] The substrate 100 can also be a sapphire substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate.

[0050] The substrate 100 can be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which can be any one of a group V element such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element or arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be any one of a group III element such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element.

[0051] The substrate 100 has a first surface 110 and a second surface 120 opposite to each other. In some embodiments, the solar cell is a single-sided cell, and the first surface 110 of the substrate 100 can be used as a light-receiving surface to receive incident light, and the second surface 120 can be used as a back surface. In some embodiments, the solar cell is a double-sided cell, and both the first surface 110 and the second surface 120 of the substrate 100 can be used as light-receiving surfaces to receive incident light. It can be understood that the back surface referred to in the embodiments of the present application can also receive incident light, but the receiving degree of the incident light is weaker than that of the light-receiving surface, and thus it is defined as a back surface.

[0052] In some embodiments, a texturing process can be performed on at least one of the first surface or the second surface of the substrate to form a textured surface on at least one of the first surface or the second surface of the substrate, so that the absorption and utilization rate of the incident light by the first surface and the second surface of the substrate can be enhanced.

[0053] In some embodiments, the texturing can be a pyramid texturing. As a common texturing, the pyramid texturing not only reduces the reflectivity of the surface of the substrate, but also forms a light trap, enhances the absorption of the incident light by the substrate, and improves the photoelectric conversion efficiency of the solar cell.

[0054] Specifically, if the solar cell is a single-sided cell, the texturing, for example, a pyramid texturing, can be formed on the light-receiving surface of the substrate, and the back surface of the substrate can be a polished surface, i.e., the back surface of the substrate is flatter than the light-receiving surface. It should be noted that for a single-sided cell, the texturing can also be formed on both the light-receiving surface and the back surface of the substrate.

[0055] If the solar cell is a double-sided cell, the texturing can be formed on both the light-receiving surface and the back surface of the substrate.

[0056] The thickness direction of the substrate 100 refers to the direction in which the second surface 120 points to the first surface 110.

[0057] In some embodiments, the solar cell can further include an emitter (not shown) on the first surface 110. In other embodiments, the emitter can be located inside the substrate 100.

[0058] In some embodiments, the emitter can be located on the entire surface of the first surface 110. The first surface 110 can include first regions and second regions arranged alternately, and the doping element concentration of the emitter on the first regions is greater than that of the emitter on the second regions, so as to form a selective emitter.

[0059] The doping element type of the emitter is opposite to that of the substrate 100, and forms a PN junction with the substrate 100.

[0060] In some embodiments, the material of the emitter can be the same as that of the substrate 100.

[0061] In some embodiments, the solar cell can further include a passivation layer (not shown). The passivation layer is located on the surface of the emitter away from the substrate 100, and has a good passivation effect on the first surface 110 of the substrate 100, reduces the defect state density of the first surface 110 of the substrate 100, and better suppresses the carrier recombination of the first surface 110 of the substrate 100. The passivation layer also has a good antireflection effect, reduces the reflection of the incident light by the first surface 110 of the substrate 100, and improves the utilization rate of the incident light by the substrate 100.

[0062] The material of the passivation layer can be at least one of silicon oxide, aluminum oxide, silicon nitride, or silicon oxynitride.

[0063] In some embodiments, the passivation layer can be a single layer structure. In some embodiments, the passivation layer can also be a multi-layer structure, the materials of the layers in the multi-layer structure can be different from each other, or the materials of a part of the number of layers can be different from each other, and the materials of the remaining part of the number of layers can be the same. For example, the passivation layer can be a multi-layer structure of a silicon nitride layer and an aluminum oxide layer.

[0064] The fine grid 101 is in electrical contact with the emitter for collecting the current generated by the solar cell and conducting it to the main grid 102.

[0065] The main grid 102 is used to collect the current collected from the fine grid 101 and transmit it to the external circuit.

[0066] The main grid 102 includes a connecting portion 112 and a soldering portion 122, and the soldering portion 122 is used to connect with the solder strip. The top surface of the soldering portion 122 is protruded in the direction away from the first surface 110 compared to the top surface of the connecting portion 112, that is, the thickness of the soldering portion 122 is thicker than that of the connecting portion 112, which can increase the contact area of the soldering portion 122 with the solder strip, and provide good connection reliability for the connection between the main grid 102 and the solder strip. At the same time, the thicker soldering portion 122 can have smaller resistance, which can reduce the loss in the process of current transmission, thereby improving the current collecting capability of the soldering portion 122, and further improving the performance of the solar cell.

[0067] In the thickness direction of the substrate 100, the difference between the top surface of the soldering portion 122 and the top surface of the connecting portion 112 is 2 μm to 10 μm, for example, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm. If the difference between the top surface of the soldering portion 122 and the top surface of the connecting portion 112 is too small, that is, the thickness of the soldering portion 122 is too thin, the contact area of the soldering portion 122 with the solder strip is very small, and the bonding force between the solder strip and the soldering portion 122 is weak, thereby reducing the connection reliability of the soldering portion 122 and the solder strip. Moreover, the resistance of the soldering portion 122 with too thin thickness is too large, which affects the current collecting capability of the soldering portion 122, and makes the performance of the solar cell poor. If the difference between the top surface of the soldering portion 122 and the top surface of the connecting portion 112 is too large, that is, the thickness of the soldering portion 122 is too thick, it will block part of the sunlight from being absorbed by the substrate 100, thereby affecting the performance of the solar cell. In other words, the difference in the above range can provide good connection reliability for the connection between the main grid 102 and the solder strip, and at the same time, it can also avoid affecting the light absorption of the solar cell due to the too thick thickness of the soldering portion 122, thereby improving the performance of the solar cell.

[0068] Further, the difference between the top surface of the soldering portion 122 and the top surface of the connecting portion 112 is 3 μm to 6 μm, for example, 3 μm, 4 μm, 5 μm, or 6 μm. When the difference is within the above range, the current collecting capability of the soldering portion 122 is good, the connection reliability of the main grid 102 and the soldering ribbon is good, and the thickness of the soldering portion 122 has little effect on the light absorption of the solar cell, so that the performance of the solar cell can be more excellent.

[0069] In some embodiments, the thickness of the soldering portion 122 is 6 μm to 12 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, or 12 μm, and the thickness of the connecting portion 112 is 2 μm to 5 μm, for example, 2 μm, 3 μm, 4 μm, or 5 μm. When the thicknesses of the soldering portion 122 and the connecting portion 112 are within the above range, the effect of the thicknesses of the soldering portion 122 and the connecting portion 112 on the light absorption of the solar cell can be avoided, and a low-resistance channel can be provided for the main grid 102 to collect the current on the fine grid 101, so that the current collection efficiency is improved.

[0070] In some embodiments, the distance between adjacent soldering portions 122 along the first direction X is 0.5 mm to 2.5 mm, for example, 0.5 mm, 1.0 mm, 1.5 mm, 2.0 mm, or 2.5 mm. The distance between adjacent soldering portions 122 along the first direction X is the spacing between adjacent soldering portions 122 on the main grid 102. It can be understood that the spacing between adjacent soldering portions 122 along the first direction X is related to the number of soldering portions 122 on the main grid 102. When the spacing is within the above range, the number of soldering portions 122 connected to the soldering ribbon on the entire main grid 102 is moderate, and a strong connection strength can be provided for the connection between the main grid 102 and the soldering ribbon, so that the situation that the main grid 102 and the soldering ribbon are separated due to insufficient connection strength between the main grid 102 and the soldering ribbon can be avoided, and the reliability of the solar cell can be improved. In addition, when the spacing is within the above range, the problem that the soldering ribbon and the main grid 102 are locally separated in the area with a large spacing between adjacent soldering portions 122 along the first direction X can be avoided, which is also beneficial to improving the reliability of the solar cell.

[0071] In some embodiments, the length of the soldering portion 122 along the first direction X is 0.2 mm to 2 mm, for example, 0.2 mm, 0.4 mm, 0.6 mm, 1.0 mm, 1.5 mm, or 2 mm.

[0072] In some embodiments, each fine grid 101 is electrically connected to the main grid 102 through a welding portion 122. In this case, the top surface of the welding portion 122 is protruded towards the direction away from the first surface 110 compared to the top surface of the connecting portion 112, i.e. the welding portion 122 has a larger thickness, and the welding portion 122 has a smaller resistance, which is beneficial for the main grid 102 to collect the current on the fine grid 101; meanwhile, the connection strength between the main grid 102 and the fine grid 101 can be improved.

[0073] It can be understood that, Figure 1 In fact, one welding portion 122 can also be connected to multiple fine grids 101.

[0074] In a specific example, each welding portion is connected to one fine grid, the length of the welding portion along the first direction is 0.2 mm, the distance between adjacent welding portions along the first direction is 0.6 mm, and the distance between adjacent fine grids along the first direction is 0.7 mm. For a whole solar cell with a length of 182 mm along the first direction, the solar cell can be provided with 227 fine grids.

[0075] In some embodiments, the distance between adjacent fine grids 101 along the first direction X is 0.7 mm to 1.2 mm, for example, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm or 1.2 mm.

[0076] Figure 3 Another top view of the solar cell provided by the embodiments of the present disclosure.

[0077] Reference Figure 3 In some embodiments, the welding portion 122 is connected to multiple fine grids 101, the connecting portion 112 is connected to multiple fine grids 101, and the distance between adjacent fine grids 101 connected to the welding portion 122 along the first direction X is smaller than the distance between adjacent fine grids 101 connected to the connecting portion 112 along the first direction X. That is, the welding portion 122 and the connecting portion 112 are both connected to fine grids 101, and the fine grids 101 connected to the welding portion 122 are arranged more densely between adjacent fine grids 101, and the number of fine grids 101 arranged on one welding portion 122 is larger. Such an arrangement is because the welding portion 122 has a larger thickness than the connecting portion 112, and the welding portion 122 has a smaller resistance, and arranging the fine grids 101 densely on the welding portion 122 can allow more photo-generated carriers to be collected and transmitted to the main grid 102, accelerate the collection speed of the current, increase the output current of the solar cell, and thus improve the performance of the solar cell. In addition, compared with the scheme in which the connecting portion 112 is not provided with fine grids 101, the connecting portion 112 is provided with fine grids 101, which can increase the utilization rate of the current collected by the main grid 102, and thus improve the performance of the solar cell.

[0078] It can be understood that, Figure 3 In the above embodiment of the solar cell, each connection part 112 is connected with two fine grids 101, in fact, one connection part 112 can also be connected with one fine grid 101, or part of the connection parts 112 are connected with two fine grids 101, part of the connection parts 112 are connected with one fine grid 101, and part of the connection parts 112 are not connected with fine grids 101.

[0079] In some embodiments, in the first direction X, the distance between the adjacent fine grids 101 connected with the welding part 122 is 0.6mm-1.0mm, for example, 0.6mm, 0.7mm, 0.8mm, 0.9mm or 1.0mm, etc.; the distance between the adjacent fine grids 101 connected with the connection part 112 is 1.0mm-3.0mm, for example, 1.0mm, 1.5mm, 2.0mm, 2.5mm or 3mm, etc.

[0080] In some embodiments, in the second direction Y, the width of the connection part 112 is less than or equal to the width of the welding part 122. When the width of the connection part 112 is less than the width of the welding part 122, the width of the connection part 112 is smaller, so that the contact area of the connection part 112 with the substrate 100 is smaller, thereby the light-shielding area of the connection part 112 with the substrate 100 is smaller, so that the solar cell can absorb more sunlight, thereby the performance of the solar cell can be improved.

[0081] In some embodiments, the connection part 112 and the welding part 122 are an integral structure. In this way, during production, the connection part 112 and the welding part 122 can be prepared at the same time in one process step, so that it is not necessary to introduce a new process step like the related art to set an additional welding point on the main grid 102, so that the process steps for preparing the solar cell can be more simplified, which is beneficial to improve the preparation efficiency of the solar cell.

[0082] In the above embodiment of the solar cell, on the one hand, the main grid 102 includes the connection part 112 and the welding part 122, when the main grid 102 and the solder strip are connected, the solder strip can be electrically connected with the main grid 102 through the welding part 122, so that it is not necessary to set an additional welding point on the main grid 102, which can avoid the problem of shielding the light absorption of the solar cell caused by setting the welding point, on the other hand, the main grid 102 does not set the fish-tail structure near the edge of the solar cell, which can avoid the problem of shielding the light absorption of the solar cell caused by setting the fish-tail structure, the above two aspects make the solar cell can absorb more sunlight, thereby the performance of the solar cell can be improved.

[0083] The top surface of the welding portion 122 protrudes towards the direction away from the first surface 110 compared to the top surface of the connecting portion 112, which can increase the contact area of the welding portion 122 and the solder ribbon, provide sufficient connection strength for the connection between the main grid 102 and the solder ribbon, and improve the current collection capability of the welding portion 122. The difference between the top surface of the welding portion 122 and the top surface of the connecting portion 112 in the thickness direction of the substrate 100 is 2-10 um, so that the welding portion 122 has good current collection capability, can provide good connection reliability for the connection between the main grid 102 and the solder ribbon, and can avoid affecting the light absorption of the solar cell due to the excessive thickness of the welding portion 122, thereby improving the performance of the solar cell.

[0084] The embodiments of the present disclosure also provide a photovoltaic module, which comprises a plurality of solar cells connected according to any one of the preceding embodiments, and is used for converting received light energy into electrical energy. It should be noted that the same or corresponding parts of the above embodiments can refer to the corresponding descriptions of the above embodiments, which will not be described hereinafter.

[0085] Figure 4 A partial perspective structure diagram of the photovoltaic module provided by the embodiments of the present disclosure is shown in FIG. 6. Figure 5 A partial perspective structure diagram of the photovoltaic module provided by the embodiments of the present disclosure is shown in FIG. 6. Figure 4 A cross-sectional view along the cross-sectional direction M1M2 is shown in FIG. 7.

[0086] In combination with reference to FIGS. 6 and 7, Figure 1 Figure 4 and Figure 5 The photovoltaic module comprises a cell string, a solder ribbon 11, an encapsulation adhesive film 12, and a cover plate 13. The cell string is connected by the solar cell 10 according to any one of the preceding embodiments; the solder ribbon 11 is used to connect adjacent solar cells 10, and the solder ribbon 11 is in electrical contact with the welding portion 122; the encapsulation adhesive film 12 is used to cover the surface of the cell string; and the cover plate 13 is used to cover the surface of the encapsulation adhesive film 12 away from the cell string.

[0087] In some embodiments, the solar cell 10 can be a whole cell or a sliced cell, where the sliced cell refers to a cell formed by cutting a whole cell. The solar cells 10 are electrically connected in the form of whole cells or multiple sliced cells to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or parallel.

[0088] In some embodiments, the plurality of cell strings can be electrically connected by the solder ribbon 11. Figure 4 ​Only the positional relationship between a solar cell 10 and a solder strip 11 is shown, i.e. the arrangement direction of the fine grids with the same polarity of the solar cell 10 is the same or in other words the fine grids with the positive polarity of each solar cell 10 are arranged towards the same side, so that the solder strip 11 connects two adjacent solar cells 10 at different sides respectively. In some embodiments, the solar cells can also be arranged with the fine grids of different polarities towards the same side, i.e. the electrodes of the adjacent solar cells are sequentially arranged in the order of the first polarity, the second polarity, the first polarity, and then the solder strip connects two adjacent solar cells at the same side.

[0089] The solder strip 11 is used to connect adjacent solar cells 10 and transmit the current collected on the solar cells 10 connected with the solder strip 11 to the module end connected with the cell string.

[0090] In some embodiments, the thickness of the solder strip 11 is 0.18mm-0.25mm, such as 0.18mm, 0.19mm, 0.2mm, 0.22mm, 0.23mm or 0.25mm, etc.

[0091] In some embodiments, the solder strip 11 comprises a base layer and a tin layer wrapping the outer side of the base layer, and the thickness of the tin layer is 5μm-10μm, such as 5μm, 6μm, 7μm, 8μm, 9μm or 10μm.

[0092] The material of the base layer is conductive material, such as copper or aluminum, etc.

[0093] Tin has a relatively low melting point, and the tin layer is wrapped on the outer side of the base layer, so that the solder strip 11 and the main grid can be melted at a relatively low temperature during the welding process, thereby realizing the connection between the solder strip 11 and the photovoltaic cell. The relatively low welding temperature can reduce the thermal damage to the cell, reduce the risk of performance degradation of the cell caused by high temperature, and improve the yield and reliability of the photovoltaic module.

[0094] The thickness of the tin layer is within the above range, which can provide sufficient protection for the base layer while enabling a relatively low welding temperature during the welding process of the solder strip 11 and the main grid, thereby improving the reliability of the photovoltaic module.

[0095] In some embodiments, the width of the solder strip 11 is 1.0mm-1.5mm, such as 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm or 1.5mm, etc. The width of the solder strip 11 is within the above range, which can avoid the problems of high cost and shading of the solar cell 10 caused by the solder strip 11 being too wide, and also provide sufficient connection strength for the connection between the solder strip 11 and the main grid.

[0096] In some embodiments, the encapsulation film 12 comprises a first encapsulation layer covering one of the front side or the back side of the solar cell 10 and a second encapsulation layer covering the other of the front side or the back side of the solar cell 10. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate (EVA) film, a polyolefin elastomer (POE) film, or a polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer can also be an EP film, an EPE film, or a PVP film.

[0097] The EP film refers to a co-extrusion film formed by laminating an EVA film and a POE film, the EPE film refers to a co-extrusion film formed by laminating an EVA film, a POE film, and an EVA film in sequence, and the PVP film refers to a co-extrusion film formed by laminating a POE film, an EVA film, and a POE film in sequence. The co-extrusion film can be manufactured by extruding one or more raw materials onto another film that has been manufactured or by bonding different kinds of films to each other during film processing.

[0098] In some cases, the first encapsulation layer and the second encapsulation layer have a boundary before lamination, and after lamination, the photovoltaic module is formed without the concept of the first encapsulation layer and the second encapsulation layer, i.e., the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0099] In some embodiments, the cover plate 13 can be a glass cover plate, a plastic cover plate, or the like having a light-transmitting function. Specifically, the surface of the cover plate facing the encapsulation film can be a concave-convex surface or a suede surface comprising a plurality of convex structures, thereby increasing the utilization rate of incident light. The cover plate 13 comprises a first cover plate opposite the first encapsulation layer and a second cover plate opposite the second encapsulation layer.

[0100] It is understood by those skilled in the art that the above embodiments are specific embodiments for implementing the present disclosure, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present disclosure, and therefore the protection scope of the present disclosure should be limited by the scope defined in the claims.

Claims

1. A solar cell, characterized by, The solar cell comprises: a substrate having opposite first and second surfaces; a plurality of fine grids spaced apart along a first direction on the first surface, the fine grids extending along a second direction; a plurality of main grids spaced apart along the second direction on the first surface, the main grids extending along the first direction, the main grids being electrically connected to the fine grids, the main grids comprising a plurality of connection portions spaced apart along the first direction, the main grids further comprising a welding portion connecting adjacent connection portions, a top surface of the welding portion being convex toward a direction away from the first surface compared to a top surface of the connection portion, and a difference between the top surface of the welding portion and the top surface of the connection portion in a thickness direction of the substrate being 2 μm to 10 μm.

2. The solar cell according to claim 1, characterized in that, The difference between the top surface of the welding portion and the top surface of the connection portion in the thickness direction of the substrate is 3 μm to 6 μm.

3. The solar cell according to claim 1, characterized in that, A distance between adjacent welding portions along the first direction is 0.5 mm to 2.5 mm.

4. The solar cell of claim 1, wherein A length of the welding portion along the first direction is 0.2 mm to 2 mm.

5. The solar cell according to any one of claims 1 to 4, characterized in that, Each of the fine grids is electrically connected to the main grid by the welding portion.

6. The solar cell according to claim 5, characterized in that, A pitch between adjacent fine grids in the first direction is 0.7 mm to 1.2 mm.

7. The solar cell according to any one of claims 1 to 4, characterized by The welding portion is connected to a plurality of the fine grids, the connection portion is connected to a plurality of the fine grids, and a distance between adjacent fine grids connected to the welding portion in the first direction is smaller than a distance between adjacent fine grids connected to the connection portion in the first direction.

8. The solar cell of claim 7, wherein, The distance between adjacent fine grids connected to the welding portion in the first direction is 0.6 mm to 1.0 mm, and the distance between adjacent fine grids connected to the connection portion in the first direction is 1.0 mm to 3.0 mm.

9. The solar cell of claim 1, wherein, A width of the connection portion in the second direction is smaller than or equal to a width of the welding portion.

10. A photovoltaic module, characterized by, The solar cell string is connected by a plurality of solar cells as claimed in any one of claims 1 to 9; A ribbon is used to connect adjacent solar cells, and the ribbon is in electrical contact with the welding portion; An encapsulant film is used to cover a surface of the solar cell string; A cover plate is used to cover a surface of the encapsulant film away from the solar cell string. ​

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