A solar cell, a battery assembly and a photovoltaic system

Abstract

The present invention is applicable to the field of photovoltaic technology, and provides a solar cell, a battery assembly and a photovoltaic system, wherein the solar cell comprises: a silicon substrate, comprising a tunneling layer, a doping layer and a passivation layer stacked in sequence; an edge main grid, which is arranged at the edge position of the silicon substrate and extends along a first direction; an edge pad point, which is arranged corresponding to the edge main grid; a connecting wire group, comprising a connecting conductor and a fine grid line, wherein the connecting conductor is arranged on the passivation layer, connects the edge main grid and the edge pad point, and the connecting conductor extends along a second direction, and the second direction intersects with the first direction; the connecting conductor forms a hollow groove, and the fine grid line is arranged at the hollow groove, passes through the passivation layer and contacts the doping layer. The fine grid line collects carriers generated by the doping layer, reduces carrier loss caused by shielding of the connecting conductor, and at the same time, the contact area between the fine grid line and the connecting conductor is small, reduces carrier recombination loss caused by slurry recombination, saves slurry use during manufacturing, and reduces the production cost of the solar cell.

Description

Technical Field

[0001] The present invention belongs to the technical field of photovoltaics, and particularly relates to a solar cell, a battery module and a photovoltaic system. Background Art

[0002] As an efficient and clean energy conversion device, a solar cell is widely used in various photovoltaic power generation systems. In a traditional solar cell structure, main grid lines, fine grid lines and Pad points are usually arranged on the cell surface for collecting and transmitting current. The main grid lines extend along one side of the cell surface, and the fine grid lines are distributed perpendicular to the main grid lines and contact the doped layer of the cell to collect photo-generated carriers.

[0003] Generally, a relatively thick connecting fine grid is arranged between the Pad point and the main grid. The relatively thick connecting fine grid causes partial areas on the cell surface to be blocked, thereby reducing the light-receiving area and affecting the photoelectric conversion efficiency. Secondly, due to the relatively thick connecting fine grid and the large contact area with the main grid line, slurry recombination is likely to occur at the contact point, resulting in carriers being recombined before reaching the electrode, reducing the performance of the cell. In addition, the extensive use of fine grid slurry not only increases the cost, but also may introduce additional defects and losses due to the uneven distribution of the slurry. Summary of the Invention

[0004] The present invention provides a solar cell, a battery module and a photovoltaic system, aiming to solve the problems that the traditional setting method affects the photoelectric conversion efficiency, is prone to recombination and has high production costs.

[0005] The present invention is implemented as follows. A solar cell includes:

[0006] A silicon substrate, including a tunneling layer, a doped layer and a passivation layer stacked in sequence;

[0007] An edge main grid, arranged at the edge position of the silicon substrate and extending along a first direction;

[0008] An edge Pad point, correspondingly arranged with the edge main grid;

[0009] A connection wire group, including a connection conductor and fine grid lines. The connection conductor is arranged on the passivation layer for connecting the edge main grid and the edge Pad point. The connection conductor extends along a second direction, and the second direction intersects with the first direction;

[0010] The connection conductor forms at least one hollow groove, and the fine grid lines are erected at the hollow groove. The fine grid lines pass through the passivation layer and contact the doped layer.

[0011] Optionally, at least one fine grid line is erected at each hollow groove.

[0012] Optionally, the fine grid lines extend along the second direction.

[0013] Optionally, along the second direction, the total length of the fine grid lines is 10% - 90% of the total length of the connection conductors.

[0014] Optionally, along the second direction, the total length of the fine grid lines is 50% - 90% of the total length of the connection conductors.

[0015] Optionally, at least one hollow groove is provided, and the hollow groove extends along the second direction.

[0016] Optionally, a plurality of hollow grooves are provided.

[0017] Optionally, along the second direction, the hollow grooves are arranged in a straight line.

[0018] Optionally, along the second direction, at least part of the hollow grooves are arranged staggeredly.

[0019] Optionally, along the second direction, the distance between adjacent hollow grooves is equal.

[0020] Optionally, along the second direction, the distance between at least part of adjacent hollow grooves is unequal.

[0021] Optionally, the hollow groove is at least one of a rectangle, a circle, a trapezoid, a triangle, a sector, and an ellipse.

[0022] Optionally, along the second direction, the fine grid lines are collinear.

[0023] Optionally, along the second direction, at least part of the fine grid lines are staggered.

[0024] Optionally, along the second direction, at least one of the fine grid lines is placed at the center position of the hollow groove.

[0025] Optionally, along the second direction, at least one of the fine grid lines is placed at the edge position of the hollow groove.

[0026] Optionally, the width of the connection conductor is 100 - 400 μm.

[0027] Optionally, the width of the connection conductor is 200 - 300 μm.

[0028] Optionally, the edge main grid includes a connection part in contact with the connection conductor and extension parts extending from both ends of the connection part, and the width of the connection conductor is 1 - 5 times the width of the connection part.

[0029] Optionally, the width of the connection conductor is 1 - 3 times the width of the connection part.

[0030] Optionally, the edge main grid includes a connection portion in contact with the connection conductor and extension portions extending along both ends of the connection portion, and the cross-sectional area of the connection conductor is 1 to 5 times that of the connection portion.

[0031] Optionally, the cross-sectional area of the connection conductor is 1 to 3 times that of the connection portion.

[0032] Optionally, a plurality of first fine grids and a plurality of second fine grids are alternately arranged on the silicon substrate along the first direction, and the edge main grid and the edge Pad points are respectively arranged on opposite side edges of the silicon substrate. The first fine grid is connected to the edge main grid and the edge Pad points on one side, and the second fine grid is connected to the edge main grid and the edge Pad points on the other side, wherein the first fine grid and the second fine grid have different polarities.

[0033] Optionally, a first region and a second region are alternately arranged on the silicon substrate along the first direction. The tunneling layer includes a first tunneling layer and a second tunneling layer, the doping layer includes a first doping layer and a second doping layer, and the passivation layer includes a first passivation layer and a second passivation layer. The first tunneling layer, the first doping layer, and the first passivation layer are sequentially stacked in the first region, and the second tunneling layer, the second doping layer, and the second passivation layer are sequentially stacked in the second region. The first doping layer and the second doping layer have different polarities;

[0034] The first fine grid is arranged in the first region and is in ohmic contact with the first doping layer, and the second fine grid is arranged in the second region and is in ohmic contact with the second doping layer.

[0035] Optionally, the connection conductor is a copper conductor or an aluminum conductor, and the fine grid line is a silver fine grid line.

[0036] Optionally, the width of the connection portion is greater than the width of the extension portion.

[0037] The present invention also provides a battery assembly including the above-mentioned solar cell.

[0038] The present invention also provides a photovoltaic system including the above-mentioned battery assembly.

[0039] The beneficial effects achieved by the present invention are as follows. Due to the provision of the edge main grid, the edge Pad points, and the connection line group connecting the edge main grid and the edge Pad points, the collected current is converged and exported. The connection line group includes a connection conductor and fine grid lines. The fine grid lines are erected on the hollow grooves formed by the connection conductor. The fine grid lines are in contact with the doped layer, while the connection conductor is not in physical contact with the doped layer. The fine grid lines collect the carriers generated by the doped layer, reducing the carrier loss caused by the shielding of the connection conductor. At the same time, the fine grid lines and the connection conductor are only in contact at both ends of the fine grid lines, with a small contact area, which can reduce the carrier recombination loss caused by the paste recombination and can also save the paste usage during manufacturing, thereby reducing the production cost of the solar cell. Description of the Drawings

[0040] Figure 1 is a partial structural schematic diagram of the solar cell provided by the present invention;

[0041] Figure 2 is a sectional view taken along the direction A of the solar cell provided by the present invention.

[0042] Description of the Reference Numerals:

[0043] 100, solar cell; 110, silicon substrate; 111, silicon wafer; 112, tunneling layer; 113, doped layer; 114, passivation layer; 120, edge main grid; 121, connection part; 122, extension part; 130, connection line group; 131, connection conductor; 132, hollow groove; 133, fine grid line; 140, edge Pad point; 150, first fine grid; 160, second fine grid. Detailed Embodiments

[0044] In order to make the objectives, technical solutions, and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the drawings and embodiments. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The embodiments described below by referring to the drawings are exemplary and are only used to explain the present invention and cannot be construed as a limitation of the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0045] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "length", "width", "upper", "lower", "left", "right", "horizontal", "top", "bottom", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0046] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0047] In the description of the present invention, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected" and "coupled" should be construed broadly. For example, it may be a fixed connection, a detachable connection or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present invention, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the horizontal height of the first feature is lower than that of the second feature.

[0049] The following disclosure provides many different embodiments or examples for implementing different structures of the present invention. To simplify the disclosure of the present invention, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0050] In the present invention, by providing an edge main grid, edge Pad points, and a connection wire group connecting the edge main grid and the edge Pad points, the collected current is converged and exported. The connection wire group includes a connection conductor and fine grid lines. The fine grid lines are erected on the hollow grooves formed by the connection conductor, and the fine grid lines are in contact with the doped layer, while the connection conductor is not in physical contact with the doped layer. The fine grid lines collect the carriers generated by the doped layer, reducing the carrier loss caused by the shielding of the connection conductor. At the same time, the fine grid lines and the connection conductor are only in contact at both ends of the fine grid lines, with a small contact area, which can reduce the carrier recombination loss caused by the paste recombination, and can also save the paste usage during manufacturing, thereby reducing the production cost of the solar cell.

[0051] Embodiment 1

[0052] As Figure 1 and Figure 2 shown, this embodiment provides a solar cell 100, including:

[0053] A silicon substrate 110, including a tunneling layer 112, a doped layer 113, and a passivation layer 114 that are sequentially stacked;

[0054] An edge main grid 120, disposed at the edge position of the silicon substrate 110 and extending along a first direction;

[0055] Edge Pad points 140, correspondingly disposed with the edge main grid 120;

[0056] A connection wire group 130, including a connection conductor 131 and fine grid lines 133. The connection conductor 131 is disposed on the passivation layer 114 and is used to connect the edge main grid 120 and the edge Pad points 140. The connection conductor 131 extends along a second direction, and the second direction intersects with the first direction;

[0057] The connection conductor 131 forms at least one hollow groove 132, and the fine grid lines 133 are erected at the hollow groove 132. The fine grid lines 133 pass through the passivation layer 114 and are in contact with the doped layer 113.

[0058] The silicon substrate 110 is the foundation of the solar cell 100, which usually includes a silicon substrate 111 and various functional layers stacked on the silicon substrate 111. That is to say, the silicon substrate 110 is the other part of the solar cell 100 excluding the metallization electrode pattern. The functional layers include a tunneling layer 112, a doping layer 113, and a passivation layer 114 that are sequentially stacked on the silicon substrate 111. Specifically, the doping layer 113 may be disposed on the tunneling layer 112, and the passivation layer 114 may be disposed on the doping layer 113; there may be other functional layers disposed between the tunneling layer 112 and the doping layer 113, and the passivation layer 114 may be disposed on the doping layer 113; or the doping layer 113 may be disposed on the tunneling layer 112, and there may be other functional layers disposed between the passivation layer 114 and the doping layer 113; or there may be other functional layers disposed between the tunneling layer 112 and the doping layer 113, and there may be other functional layers disposed between the passivation layer 114 and the doping layer 113.

[0059] The tunneling layer 112 is disposed between the silicon substrate 111 and the doping layer 113, providing a transmission channel between the doping layer 113 and the silicon substrate 111 through the tunneling effect. The passivation layer 114 is disposed on the upper layer of the doping layer 113. Commonly used materials include silicon dioxide ( ), silicon nitride ( ), and aluminum oxide ( ), which can combine with the dangling bonds on the semiconductor surface to reduce the surface state density, thereby improving the electrical characteristics of the semiconductor surface. And the passivation layer 114 is usually disposed on the outermost layer of each functional layer, which can effectively block the diffusion of impurities (such as metal ions, water vapor, etc.) in the external environment and protect the performance stability of the underlying structure. At the same time, the commonly used material of the passivation layer 114 is an insulating material, which can isolate the doping layer 113 from other electrical regions or electrical components to avoid current leakage and interference.

[0060] The doping layer further includes a P-type doping layer and an N-type doping layer. The P-type doping layer and the N-type doping layer can be disposed on one side or both sides of the silicon substrate 111 to form a P-N junction, generating a photovoltaic effect. When light shines on the solar cell 100, photons can excite electrons to jump from the valence band to the conduction band, forming electron-hole pairs. These carriers are separated at the P-N junction due to the electric field effect, generating current.

[0061] The edge main grid 120 is located at the edge position of the silicon substrate 110, placed on the passivation layer 114, and extends along the first direction. The main function of the main grid is to converge and export the current collected from the fine grids (fine grid lines 133 or other grid lines in physical contact with the doping layer). Therefore, the main grid needs to have good electrical conductivity and sufficient cross-sectional area to carry a large current. The edge Pad point 140 is correspondingly arranged with the edge main grid 120 and is placed close to the edge main grid 120. It can be understood that the edge Pad point 140 is close to the edge main grid 120, that is, the distance between the edge Pad point 140 and the edge main grid 120 is close. When there are other Pad points on the solar cell 100, the distance between the edge Pad point 140 and the edge main grid 120 is less than the distance between other Pad points and the edge main grid 120. The edge Pad point 140 is a conductor and is used to connect and output electricity. The number of edge Pad points 140 can be one or multiple, which is specifically set according to the actual requirements of the solar cell 100. When multiple edge Pad points 140 are correspondingly arranged with one edge main grid 120, the multiple edge Pad points 140 are arranged along the first extension direction.

[0062] The connection wire group 130 includes a composite structure composed of a connection conductor 131 and fine grid lines 133. Among them, the connection conductor 131 is arranged on the passivation layer 114, and the passivation layer 114 isolates the connection conductor 131 and the doping layer 113 to prevent the connection conductor 131 and the doping layer 113 from directly conducting. The connection conductor 131 connects the edge main grid 120 and the edge Pad point 140. Since the connection conductor 131, the edge main grid 120, and the edge Pad point 140 are all conductors and are electrically connected, the connection conductor 131 can direct the carriers (electrons or holes) collected by the edge main grid 120 to the edge Pad point 140, and then export them outward through the edge Pad point 140. For example, the edge Pad point 140 is connected to a solder strip, and the collected carriers are exported through the solder strip. The connection conductor 131 extends along the second direction, and the second direction intersects with the first direction. This design can reduce shading, ensure that more light energy reaches the doping layer, and improve the photoelectric conversion efficiency.

[0063] Specifically, the edge main grid 120 can extend along the longitudinal direction of the silicon substrate 110, and the connection conductor 131 can extend along the transverse direction of the silicon substrate 110. That is, the first direction can be the longitudinal direction of the solar cell 100, and the second direction can be the transverse direction of the solar cell 100, and the two are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction can also be other directions. For example, the two can be the diagonal directions of the silicon substrate 110 respectively, and specific details are not limited here.

[0064] A hollow groove 132 is formed on the connecting conductor 131. The fine grid line 133 is arranged at the hollow groove 132 of the connecting conductor 131. Both ends of the fine grid line 133 are respectively connected to the opposite side walls of the hollow groove 132 and pass through the passivation layer 114 to be in direct contact with the doping layer 113. The direct contact of the two conductive media forms a conductive channel for collecting the carriers generated by the doping layer and reducing the carrier loss caused by the shielding of the connecting conductor 131. Specifically, the shape of the hollow groove 132 can be at least one of a rectangle, a circle, a trapezoid, a triangle, a sector, and an ellipse, which is not limited herein.

[0065] At the contact position between the fine grid line 133 and the connecting conductor 131, carriers will be captured and recombined, resulting in recombination loss. The fine grid line 133 is only in contact with the connecting conductor 131 at both ends, and the contact area between the fine grid line 133 and the connecting conductor 131 is small, which can reduce the carrier recombination loss caused by the paste recombination. At the same time, it can also save the paste usage during manufacturing, thereby reducing the production cost of the solar cell 100.

[0066] In this embodiment, by providing the edge main grid 120, the edge Pad point 140, and the connection line group 130 connecting the edge main grid 120 and the edge Pad point 140, the collected current is converged and exported. The connection line group 130 includes the connecting conductor 131 and the fine grid line 133. The fine grid line 133 is arranged on the hollow groove 132 formed by the connecting conductor 131. The fine grid line 133 is in contact with the doping layer, while the connecting conductor 131 is not in contact with the doping layer. The fine grid line 133 collects the carriers generated by the doping layer and reduces the carrier loss caused by the shielding of the connecting conductor 131. At the same time, the fine grid line 133 and the connecting conductor 131 are only in contact at both ends of the fine grid line 133, and the contact area is small, which can reduce the carrier recombination loss caused by the paste recombination and can also save the paste usage during manufacturing, thereby reducing the production cost of the solar cell 100.

[0067] In one embodiment, at least one fine grid line 133 is arranged at the hollow groove 132.

[0068] The number of the fine grid lines 133 arranged at one hollow groove 132 can be one or multiple. Arranging only one fine grid line 133 can reduce the shielding area and improve the photoelectric conversion efficiency of the battery. When multiple fine grid lines 133 are arranged, not only can the carriers be collected better, but also it can be used as a redundant design. When a certain fine grid line 133 is broken, the other fine grid lines 133 can continue to collect current, and the stability is better. When multiple fine grids are arranged, the multiple fine grids can be arranged in parallel or at a certain angle, which is not limited herein.

[0069] In one embodiment, the fine grid line 133 extends along the second direction.

[0070] The connecting conductor 131 extends along the second direction, and the extending direction of the fine grid line 133 is the same as that of the connecting conductor 131. This arrangement helps the uniform transmission of current, reduces the local resistance inside the battery, and improves the overall current collection efficiency.

[0071] Embodiment 2

[0072] In one embodiment, along the second direction, the total length of the fine grid line 133 is 10% - 90% of the total length of the connecting conductor 131.

[0073] The connecting conductor 131 extends along the second direction. The total length of the connecting conductor 131 along the second direction refers to the length of the connecting conductor 131 between the edge main grid 120 and the edge Pad point 140. The total length of the fine grid line 133 along the second direction is, that is, the projected length of the fine grid line 133 in the second direction. It can be understood that when multiple fine grid lines 133 are provided, if the projections of the multiple fine grid lines 133 in the second direction overlap, the length of the overlapping part is only calculated once.

[0074] The total length of the fine grid line 133 is 10% - 90% of the total length of the connecting conductor 131. For example, assuming the total length of the connecting conductor 131 is 10 mm, the total length of the fine grid line 133 can be from 1 mm to 9 mm. This ensures that the fine grid line 133 can effectively transmit current without overly blocking the silicon substrate 110 and affecting the light absorption efficiency. By reasonably designing the length of the fine grid line 133, damage caused by excessive material accumulation can be avoided, and the long-term reliability of the battery can be improved.

[0075] In one embodiment, along the second direction, the total length of the fine grid line 133 is 50% - 90% of the total length of the connecting conductor 131.

[0076] The total length of the fine grid line 133 along the second direction is 50% - 90% of the total length of the connecting conductor 131. For example, assuming the total length of the connecting conductor 131 is 10 mm, the total length of the fine grid line 133 can be from 5 mm to 9 mm. A higher proportion of the length of the fine grid line 133 can maximize the carrier collection efficiency, improve the photoelectric conversion efficiency of the battery, and compared with full-length coverage, this method can reduce the amount of paste used and lower the cost.

[0077] Embodiment 3

[0078] In one embodiment, at least one hollow groove 132 is provided, and the hollow groove 132 extends along the second direction.

[0079] The extending direction of the hollow groove 132 is the same as that of the connecting conductor 131, reducing the blockage of the connecting conductor 131 to the silicon substrate 110, improving the light transmittance, enabling more light to pass through the hollow groove 132 and irradiate onto the silicon substrate 110, and improving the photoelectric conversion efficiency of the battery.

[0080] In one embodiment, the total area of the hollow grooves 132 accounts for 1% to 50% of the total area of the connecting conductor 131.

[0081] It can be understood that the "area" in this embodiment refers to the area of the side of the connecting conductor 131 facing away from the silicon substrate. Generally, the thickness of the connecting conductor 131 is relatively thin. If the proportion of the hollow grooves 132 is too large, the part of the connecting conductor 131 for current transmission becomes smaller, which is not conducive to current transmission. The total area of the hollow grooves 132 is the sum of the areas of each hollow groove, accounting for 1% to 50% of the total area of the connecting conductor 131, which is beneficial to ensuring that the connecting conductor 131 retains enough conductive parts for current transmission.

[0082] In one embodiment, a plurality of hollow grooves 132 are provided.

[0083] The plurality of hollow grooves 132 can further reduce the shielding of the silicon substrate 110 by the connecting conductor 131, improve the light absorption efficiency of the battery. At the same time, the use of connecting materials is reduced, and the cost is lowered.

[0084] Specifically, along the second direction, the hollow grooves 132 are arranged in the same straight line, that is, the center lines of the plurality of hollow grooves 132 along the second direction coincide. Arranging the hollow grooves 132 in the same straight line can ensure more uniform carrier collection and reduce the influence of local non-uniformity on the battery performance. At the same time, the hollow grooves 132 arranged in a straight line are easy to be realized by processes such as screen printing, reducing the manufacturing difficulty.

[0085] Alternatively, along the second direction, at least some of the hollow grooves 132 are arranged staggeredly, that is, the center lines of at least some of the hollow grooves 132 are offset along the second direction. Specifically, some of the hollow grooves 132 can be arranged in the same straight line, and some of the hollow grooves 132 can be arranged staggeredly, or all of the hollow grooves 132 can be arranged staggeredly. The staggeredly arranged hollow grooves 132 can prevent the fine grid lines 133 from concentrating in a certain area, reduce the influence of local shielding on the battery performance, make better use of light energy, and improve the photovoltaic conversion efficiency.

[0086] In one embodiment, along the second direction, the distance between adjacent hollow grooves 132 is equal.

[0087] If the position on any hollow groove 132 closest to the adjacent hollow groove 132 is taken as the vertex, the distance between the vertices of two adjacent hollow grooves 132 is the distance between the two hollow grooves 132. The equal distance ensures the uniform distribution of the hollow grooves 132 and the fine grid lines 133 on the connecting conductor 131, and improves the uniformity of carrier collection.

[0088] In one embodiment, along the second direction, the distance between at least some adjacent hollow grooves 132 is unequal.

[0089] The distances between all adjacent hollow slots 132 may not be equal. For example, if four hollow slots 132 are provided, the distance between the first hollow slot 132 and the second hollow slot 132 is 50 μm, the distance between the second hollow slot 132 and the third hollow slot 132 is 60 μm, and the distance between the third hollow slot 132 and the fourth hollow slot 132 is 70 μm. Alternatively, the distances between some adjacent hollow slots 132 may be equal, while the distances between some other adjacent hollow slots 132 may not be equal. For example, the distance between the first hollow slot 132 and the second hollow slot 132 is 50 μm, the distance between the second hollow slot 132 and the third hollow slot 132 is 50 μm, and the distance between the third hollow slot 132 and the fourth hollow slot 132 is 70 μm.

[0090] The design with unequal spacing can optimize the distribution of the fine grid lines 133 according to the light intensity and the requirements of the battery design, and reduce local shading.

[0091] In one embodiment, along the second direction, the fine grid lines 133 are collinear.

[0092] When a plurality of hollow slots 132 are formed on the connecting conductor 131, the fine grid lines 133 erected on each hollow slot 132 are distributed along the same straight line. The collinear arrangement can collect carriers concentratedly, reduce the influence of dispersion on the battery performance. At the same time, the collinear fine grid lines 133 can simplify the design and manufacturing processes and improve the production efficiency.

[0093] In one embodiment, along the second direction, the fine grid lines 133 are staggered.

[0094] When a plurality of hollow slots 132 are formed on the connecting conductor 131, at least some of the fine grid lines 133 erected on each hollow slot 132 are not distributed along the same straight line. Specifically, all the fine grid lines 133 may not be distributed along the same straight line, that is, all the fine grid lines 133 are not collinear; or some of the fine grid lines 133 may be distributed along the same straight line, while some other fine grid lines 133 are not. For example, if four hollow slots 132 are provided, and one fine grid line 133 is erected on each hollow slot 132, among which, three fine grid lines 133 are distributed along the same straight line, and one fine grid line 133 has a certain distance or an angle with the three collinear fine grid lines 133.

[0095] In one embodiment, along the second direction, at least one fine grid line 133 is placed at the central position of the hollow slot 132.

[0096] That is, at least one fine grid line 133 is disposed at a position overlapping with the center line of the hollow groove 132. At the central position, the distances between the fine grid line 133 and the groove walls of the hollow grooves 132 on both sides are equal, ensuring the uniform distribution of the fine grid line 133 in the groove and avoiding local overheating. At the central position, the fine grid line 133 can also provide an optimal contact point, reduce the contact resistance, and improve the carrier transport efficiency.

[0097] In one embodiment, along the second direction, at least one fine grid line 133 is placed at the edge position of the hollow groove 132.

[0098] That is, at least one fine grid line 133 is disposed at a position not overlapping with the center line of the hollow groove 132, that is, the fine grid line 133 is offset from the center line position of the hollow groove 132. Specifically, it may be at a certain distance or at a certain angle from the center line position. The fine grid line 133 at the edge position can optimize the light-receiving area and reduce the influence of shading on the battery performance.

[0099] Embodiment Four

[0100] In one embodiment, the width of the connecting conductor 131 is 100 - 400 μm.

[0101] Since the connecting conductor 131 extends along the second direction, the width of the connecting conductor 131 refers to the distance between two opposite side edges of the connecting conductor 131 perpendicular to the second extension direction.

[0102] The wider the width of the connecting conductor 131, the wider the channel width provided for the carriers to pass through, the smaller the resistance, and the more conducive to the carrier transport. However, the wider the width of the connecting conductor 131, the greater the shielding of the silicon substrate 110. Through experimental verification, when the width of the connecting conductor 131 is between 100 - 400 μm, it can ensure that the connecting conductor 131 has good electrical conductivity, reduce the current transmission loss, and at the same time, will not have too much impact on the photoelectric conversion efficiency of the solar cell 100.

[0103] Specifically, the width of the connecting conductor 131 can be 100 μm, 120 μm, 140 μm, 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 260 μm, 280 μm, 300 μm, 320 μm, 340 μm, 350 μm, 370 μm, 380 μm, 385 μm, 390 μm, 400 μm, or other values between 100 - 400 μm, which are not limited herein.

[0104] In one embodiment, the width of the connecting conductor 131 is 200 - 300 μm. Specifically, when the width of the connecting conductor 131 is between 200 - 300 μm, the conductivity and the shielding effect on the silicon substrate 110 can be better balanced, improving the overall performance of the battery. While ensuring the performance, excessive shielding of the silicon substrate 110 is avoided, which may affect the photoelectric conversion efficiency.

[0105] Embodiment Five

[0106] In one embodiment, the edge main grid 120 includes a connecting portion 121 in contact with the connecting conductor 131 and extending portions 122 extending along both ends of the connecting portion 121. The width of the connecting conductor 131 is 1 - 5 times the width of the connecting portion 121.

[0107] Since the connecting conductor 131 extends along the second direction, the width of the connecting conductor 131 refers to the distance between two opposite side edges of the connecting conductor 131 perpendicular to the second extension direction. And the edge main grid 120 extends along the first direction, so the width of the edge main grid 120 refers to the distance between two opposite side edges of the edge main grid 120 perpendicular to the first extension direction.

[0108] The edge main grid 120 is in contact with the connecting conductor 131 at the connecting portion 121 of the connecting conductor 131. At the connecting portion 121, the connecting conductor 131 transfers the carriers collected by the edge Pad point 140 to the edge main grid 120. A wider connecting conductor 131 can reduce the resistance, which is beneficial to the transfer of carriers on the connecting conductor 131. At the same time, the width of the connecting portion 121 is 0.2 - 1 times the width of the connecting conductor 131, avoiding that the connecting portion 121 is too narrow to allow the carriers transferred by the connecting conductor 131 to pass smoothly, affecting the battery transfer efficiency.

[0109] The width of the connecting conductor 131 being 1 - 5 times the width of the connecting portion 121 can optimize the current collection and reduce the current loss. For example, the width of the connecting portion 121 is 100 μm, and the width of the connecting conductor 131 is 400 μm (4 times).

[0110] In one embodiment, the width of the connecting conductor 131 is 1 - 3 times the width of the connecting portion 121.

[0111] Further optimizing the width of the connecting conductor 131 within the range of 1 - 3 times the width of the connecting portion 121 can further optimize the conductivity and avoid a large difference in the widths of the connecting conductor 131 and the connecting portion 121, affecting the transfer efficiency.

[0112] For example, the width of the connecting portion 121 is 150 μm, and the width of the connecting conductor 131 is 300 μm (2 times).

[0113] Embodiment Six

[0114] In one embodiment, the edge main grid 120 includes a connection portion 121 in contact with the connection conductor 131 and extension portions 122 extending along both ends of the connection portion 121. The cross-sectional area of the connection conductor 131 is 1 to 5 times that of the connection portion 121.

[0115] Since the connection conductor 131 extends in the second direction, a cross-section of the connection conductor 131 is intercepted perpendicular to the second extension direction. And the edge main grid 120 extends in the first direction, and a cross-section of the edge main grid 120 is intercepted perpendicular to the first extension direction.

[0116] The edge main grid 120 is in contact with the connection conductor 131 at the connection portion 121 of the connection conductor 131. At the connection portion 121, the connection conductor 131 transfers the carriers collected by the edge Pad point 140 onto the edge main grid 120. The connection conductor 131 with a larger cross-sectional area can reduce resistance, which is beneficial to the transfer of carriers on the connection conductor 131. At the same time, the cross-sectional area of the connection portion 121 is 0.2 to 1 times that of the connection conductor 131, avoiding that the cross-sectional area of the connection portion 121 is too small to allow the carriers transferred by the connection conductor 131 to pass smoothly, affecting the battery transfer efficiency.

[0117] The cross-sectional area of the connection conductor 131 being 1 to 5 times that of the connection portion 121 can optimize current collection and reduce current loss. For example, the cross-sectional area of the connection portion 121 is 100 μm, and the cross-sectional area of the connection conductor 131 is 400 μm (4 times).

[0118] In one embodiment, the cross-sectional area of the connection conductor 131 is 1 to 3 times that of the connection portion 121.

[0119] Further optimizing the cross-sectional area of the connection conductor 131 within the range of 1 to 3 times that of the connection portion 121 can further optimize the conductivity and avoid a large difference in the cross-sectional areas of the connection conductor 131 and the connection portion 121, affecting the transfer efficiency.

[0120] For example, the cross-sectional area of the connection portion 121 is 150 μm, and the cross-sectional area of the connection conductor 131 is 300 μm (2 times).

[0121] Embodiment Seven

[0122] As Figure 1As shown, in one embodiment, a number of first fine grids 150 and a number of second fine grids 160 are alternately arranged on a silicon substrate 110 in a first direction. Edge main grids 120 and edge Pad points 140 are respectively arranged at two opposite side edges of the silicon substrate 110. The first fine grid 150 is connected to the edge main grid 120 and the edge Pad point 140 on one side, and the second fine grid 160 is connected to the edge main grid 120 and the edge Pad point 140 on the other side. Among them, the first fine grid 150 and the second fine grid 160 have opposite polarities.

[0123] It can be understood that a P-type region and an N-type region are arranged on the silicon substrate 110. The P-type region and the N-type region form regions with different electrical characteristics, supporting the formation of a P-N junction and the separation of carriers. The first fine grid 150 and the second fine grid 160 are respectively arranged in regions of two polarities. Specifically, the first fine grid 150 can be arranged in the P-type region and the second fine grid 160 can be arranged in the N-type region, or specifically, the first fine grid 150 can be arranged in the N-type region and the second fine grid 160 can be arranged in the P-type region.

[0124] The two opposite side edges of the silicon substrate 110 are respectively the first side edge and the second side edge. Edge main grids 120 and edge Pad points 140 corresponding to the edge main grids 120 are respectively arranged at the two side edges. Specifically, the first fine grid 150 and the second fine grid 160 can be connected to the edge Pad points 140 through wires, and the wires used for connection are not in physical contact with the doping layer.

[0125] Taking the first fine grid 150 arranged in the P-type region and the second fine grid 160 arranged in the N-type region as an example: The first fine grid 150 collects holes generated in the P-type region. The first fine grid 150 is connected to the edge main grid 120 and the edge Pad point 140 on the first side edge, and transfers the holes collected by the first fine grid 150 to the edge main grid 120 and connects to a load through the edge main grid 120. Specifically, some of the first fine grids 150 are directly connected to the edge main grid 120 on the first side edge, and some of the first fine grids 150 are connected to the edge Pad points 140 and are connected to the edge main grid 120 on the first side edge through a connection wire group 130. The second fine grid 160 collects electron holes generated in the N-type region. The second fine grid 160 is connected to the edge main grid 120 and the edge Pad point 140 on the second side edge, and transfers the electrons collected by the second fine grid 160 to the edge main grid 120 and connects to a load through the edge main grid 120. Specifically, some of the second fine grids 160 are directly connected to the edge main grid 120 on the second side edge, and some of the second fine grids 160 are connected to the edge Pad points 140 and are connected to the edge main grid 120 on the second side edge through a connection wire group 130.

[0126] In one embodiment, a first region and a second region are alternately arranged on a silicon substrate 110 along a first direction. The tunneling layer 112 includes a first tunneling layer and a second tunneling layer. The doping layer 113 includes a first doping layer and a second doping layer. The passivation layer 114 includes a first passivation layer and a second passivation layer. The first tunneling layer, the first doping layer, and the first passivation layer are sequentially stacked in the first region. The second tunneling layer, the second doping layer, and the second passivation layer are sequentially stacked in the second region. The first doping layer and the second doping layer have opposite polarities; a first fine grid 150 is disposed in the first region and is in ohmic contact with the first doping layer, and a second fine grid 160 is disposed in the second region and is in ohmic contact with the second doping layer.

[0127] Specifically, the silicon substrate 110 includes a silicon substrate 111, a tunneling layer 112, a doping layer 113, and a passivation layer 114. The doping layer 113 is disposed on the silicon substrate 111. The tunneling layer 112 includes a first tunneling layer and a second tunneling layer. The doping layer 113 includes a first doping layer and a second doping layer. The passivation layer 114 includes a first passivation layer and a second passivation layer. The first tunneling layer, the first doping layer, and the first passivation layer are sequentially stacked in the first region. The second tunneling layer, the second doping layer, and the second passivation layer are disposed in the second region. The first region and the second region are alternately arranged along the first direction, that is, the first doping layer and the second doping layer are alternately arranged along the first direction on the silicon substrate 111. The first doping layer and the second doping layer have opposite polarities. The first doping layer may be a P-type doping layer and the second doping layer may be an N-type doping layer, or the first doping layer may be an N-type doping layer and the second doping layer may be a P-type doping layer. The first polar doping layer and the second polar doping layer form regions with different electrical characteristics, supporting the formation of a P-N junction and the separation of carriers.

[0128] The first fine grid 150 is disposed in the first region and is in ohmic contact with the first doping layer, that is, the first fine grid 150 passes through the first passivation layer and contacts the first doping layer, forming a conductive channel therebetween to collect the carriers generated in the first region. The second fine grid 160 is disposed in the second region and is in ohmic contact with the second doping layer, that is, the second fine grid 160 passes through the second passivation layer and contacts the first doping layer, forming a conductive channel therebetween to collect the carriers generated in the second region. Alternately arranging the first region and the second region can ensure the uniform distribution of the fine grid lines 133 on the silicon substrate 110 and improve the uniformity of carrier collection.

[0129] The first region and the second region are alternately arranged, that is, the first region and the second region are provided on the same piece of the silicon substrate 110, and usually, they are provided on the backlight side of the silicon substrate 110. The first fine grid 150 and the second fine grid 160 are respectively provided corresponding to the first region and the second region, so the first fine grid 150 and the second fine grid 160 are provided on the backlight side of the silicon substrate 110. There is no fine grid blocking on the light-facing side of the silicon substrate 110, so the light absorption area can be maximally increased, the shadow loss can be reduced, and the photoelectric conversion efficiency of the battery can be significantly improved.

[0130] Embodiment Eight

[0131] In one embodiment, the connecting conductor 131 is a copper conductor or an aluminum conductor, and the fine grid line 133 is a silver fine grid line.

[0132] For example, the connecting conductor 131 is a copper conductor with a width of 250 μm, and the fine grid line 133 is a silver fine grid line with a width of 50 μm. The connecting conductor 131 mainly plays the role of transporting carriers. Copper and aluminum have good electrical conductivity, which can reduce the resistance on the connecting conductor 131 and improve the current transmission efficiency. At the same time, copper and aluminum have lower costs, reducing the overall manufacturing cost.

[0133] The fine grid line 133 needs to contact the doping layer, and in addition to having excellent electrical conductivity, it also needs to have good contact performance. The silver fine grid line has excellent electrical conductivity and contact performance, which can improve the reliability of the battery.

[0134] According to the different functions of the link conductor and the fine grid line 133, different conductive materials are selected, saving the use of silver paste and reducing the production cost.

[0135] Embodiment Nine

[0136] In one embodiment, the width of the connecting portion 121 is greater than the width of the extending portion 122.

[0137] The connecting portion 121 is used to connect with the connecting conductor 131 and receive the carriers transmitted by the connecting conductor 131. That is, the carriers transmitted by the connecting conductor 131 converge at the connecting portion 121. The wider connecting portion 121 can optimize the convergence of carriers and reduce the loss during the current transmission process. The width of the extending portion 122 is less than the width of the connecting portion 121, and the narrower extending portion 122 can reduce the material usage and lower the cost.

[0138] Embodiment Ten

[0139] This embodiment provides a battery assembly, including the solar cell 100 in the above embodiment.

[0140] The battery module may include a plurality of solar cells 100. The plurality of solar cells 100 in the battery module may be connected in series in sequence to form a battery string. Each battery string may be connected in series, in parallel, or in a series-parallel combination to achieve the converging output of current. For example, the connection between each solar cell can be realized by welding solder tapes, and the connection between each battery string can be realized by a bus bar.

[0141] The battery module may further include a metal frame, a backsheet, a photovoltaic glass, and an encapsulant film (not shown in the figures). The encapsulant film may be filled between the light-facing surface of the solar cell 100 and the photovoltaic glass, the backlight surface and the backsheet, and adjacent solar cells, etc. As a filler, it can be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulant film can be an EVA encapsulant film or a POE encapsulant film, and the specific selection can be made according to the actual situation and is not limited here.

[0142] The photovoltaic glass may cover the encapsulant film on the light-facing surface of the solar cell 100. The photovoltaic glass can be ultra-white glass, which has a high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, the light transmittance of the ultra-white glass can reach more than 92%, and it can protect the solar cell 100 without significantly affecting the efficiency of the solar cell 100. At the same time, the encapsulant film can bond the photovoltaic glass and the solar cell 100 together, and the presence of the encapsulant film can seal and insulate the solar cell 100 and prevent water and moisture.

[0143] The backsheet may be attached to the encapsulant film on the backlight surface of the solar cell 100. The backsheet can protect and support the solar cell 100, and has reliable insulation, water resistance, and aging resistance. There are multiple choices for the backsheet, which can usually be tempered glass, plexiglass, aluminum alloy TPT composite film, etc. The specific settings can be made according to the specific situation and are not limited here. The whole composed of the backsheet, the solar cell 100, the encapsulant film, and the photovoltaic glass can be arranged on the metal frame. The metal frame, as the main external support structure of the entire battery module, can provide stable support and installation for the battery module. For example, the battery module can be installed at the required installation position through the metal frame.

[0144] The beneficial effects of the battery module in this embodiment are the same as those of the above-mentioned solar cell 100, and will not be elaborated here.

[0145] Embodiment Ten

[0146] The embodiment provides a photovoltaic module, including the battery module in the above embodiment.

[0147] The photovoltaic system can be applied in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to devices or apparatuses that use solar energy for power generation, such as user solar power supplies, solar street lights, solar cars, solar buildings, and so on. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this, that is to say, the photovoltaic system can be applied in all fields that require solar power generation. Taking the photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array can be an array combination of multiple battery components. For example, multiple battery components can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the combiner box, and the combiner box can collect the current generated by the photovoltaic arrays. The collected current flows through the inverter and is converted into alternating current required by the mains power grid and then connected to the mains network to achieve solar power supply.

[0148] The beneficial effects of the photovoltaic system in this embodiment are the same as those of the above-mentioned battery components, and will not be elaborated here.

[0149] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A solar cell, characterized in that: include: A silicon substrate, comprising a tunneling layer, a doping layer and a passivation layer stacked in sequence; An edge main gate is arranged at an edge position of the silicon substrate and extends along a first direction; Edge Pad points, arranged corresponding to the edge main grid; A connection line group, comprising a connection conductor and a thin gate line, wherein the connection conductor is disposed on the passivation layer and is used to connect the edge main gate and the edge pad point, and the connection conductor extends along a second direction, and the second direction intersects the first direction; The connecting conductor forms at least one hollow groove, the fine gate line is arranged at the hollow groove, and the fine gate line passes through the passivation layer and contacts the doping layer.

2. The solar cell according to claim 1, characterized in that At least one thin grid line is set up at each of the hollow grooves.

3. The solar cell according to claim 1, characterized in that The fine gate lines extend along the second direction.

4. The solar cell according to claim 1, characterized in that Along the second direction, the total length of the thin gate lines is 10% to 90% of the total length of the connecting conductor.

5. The solar cell according to claim 4, characterized in that: Along the second direction, the total length of the thin gate lines is 50% to 90% of the total length of the connecting conductor.

6. The solar cell according to claim 1 or 2, characterized in that: At least one hollow groove is provided, and the hollow groove extends along the second direction.

7. The solar cell according to claim 6, characterized in that The hollow grooves are arranged in plurality.

8. The solar cell according to claim 7, characterized in that Along the second direction, the hollow grooves are arranged along the same straight line.

9. The solar cell according to claim 7, characterized in that: Along the second direction, at least some of the hollow grooves are arranged in a staggered manner.

10. The solar cell according to any one of claims 7 to 9, characterized in that: Along the second direction, distances between adjacent hollow grooves are equal.

11. The solar cell according to any one of claims 7 to 9, characterized in that: Along the second direction, distances between at least some adjacent hollow grooves are unequal.

12. The solar cell according to claim 2, characterized in that: The hollow groove is at least one of a rectangular, circular, trapezoidal, triangular, fan-shaped, and elliptical shape.

13. The solar cell according to claim 7, characterized in that: Along the second direction, the fine grid lines are collinear.

14. The solar cell according to claim 7, characterized in that: Along the second direction, at least some of the fine grid lines are staggered.

15. The solar cell according to claim 7, characterized in that: Along the second direction, at least one of the thin grid lines is placed at a central position of the hollow groove.

16. The solar cell according to claim 7, characterized in that: Along the second direction, at least one of the thin grid lines is placed at an edge of the hollow groove.

17. The solar cell according to claim 1, characterized in that: The total area of ​​the hollow grooves accounts for 1% to 50% of the total area of ​​the connecting conductor.

18. The solar cell according to claim 1, characterized in that: The width of the connecting conductor is 100-400 μm.

19. The solar cell according to claim 18, characterized in that The width of the connecting conductor is 200-300 μm.

20. The solar cell according to claim 1, characterized in that The edge main grid includes a connection portion contacting the connection conductor and extension portions extending along two ends of the connection portion, and the width of the connection conductor is 1 to 5 times the width of the connection portion.

21. The solar cell according to claim 20, characterized in that The width of the connecting conductor is 1 to 3 times the width of the connecting portion.

22. The solar cell according to claim 1, characterized in that The edge main grid includes a connection portion in contact with the connection conductor and extension portions extending along two ends of the connection portion, and the cross-sectional area of ​​the connection conductor is 1 to 5 times the cross-sectional area of ​​the connection portion.

23. The solar cell according to claim 22, characterized in that The cross-sectional area of ​​the connecting conductor is 1 to 3 times the cross-sectional area of ​​the connecting portion.

24. The solar cell according to claim 1, characterized in that A plurality of first fine gates and a plurality of second fine gates are alternately arranged along the first direction on the silicon substrate, and the edge main gate and the edge Pad point are respectively set on the two opposite edges of the silicon substrate, the first fine gate is connected to the edge main gate and the edge Pad point on one side, and the second fine gate is connected to the edge main gate and the edge Pad point on the other side, wherein the first fine gate and the second fine gate have different properties.

25. The solar cell according to claim 24, characterized in that A first region and a second region are alternately arranged on the silicon substrate along the first direction, the tunneling layer includes a first tunneling layer and a second tunneling layer, the doping layer includes a first doping layer and a second doping layer, and the passivation layer includes a first passivation layer and a second passivation layer, the first tunneling layer, the first doping layer and the first passivation layer are sequentially stacked in the first region, and the second tunneling layer, the second doping layer and the second passivation layer are sequentially stacked in the second region, and the first doping layer and the second doping layer have different polarities; The first fine gate is disposed in the first region and is in ohmic contact with the first doped layer. The second fine gate is disposed in the second region and is in ohmic contact with the second doped layer.

26. The solar cell according to claim 1, characterized in that The connecting conductor is a copper conductor or an aluminum conductor, and the fine grid wire is a silver fine grid wire.

27. The solar cell according to any one of claims 20 to 23, characterized in that: The width of the connecting portion is greater than the width of the extending portion.

28. A battery assembly, characterized in that: A solar cell comprising any one of claims 1 to 27.

29. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 28.

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