Back contact cell and manufacturing method therefor, and photovoltaic module

Abstract

The present application discloses a back contact cell and a manufacturing method therefor, and a photovoltaic module. The back contact cell comprises: a substrate, having a first surface and a second surface which are opposite to each other; and a first doped layer and a second doped layer, which are alternately provided on the first surface, wherein doping types of the first doped layer and the second doped layer are opposite, and doping types of the second doped layer and the substrate are the same. The substrate has an edge, a first isolation region is provided between the boundary of the first doped layer adjacent to the edge and the edge, a second isolation region is provided between the boundary of the second doped layer adjacent to the edge and the edge, and the width of at least part of the first isolation region is greater than that of at least part of the second isolation region. Considering that a PN junction region formed between the first doped layer and the substrate which have opposite doping types has a higher electric leakage risk, the width of at least part of the first isolation region is enabled to be greater than that of at least part of the second isolation region, so that a wider first isolation region is provided at the PN junction region formed between the first doped layer and the substrate to reduce the electric leakage risk and minimize potential safety hazards.

Description

A back contact battery and its preparation method, and a photovoltaic module

[0001] Cross-reference to related applications

[0002] This application claims priority and benefit to Chinese patent application filed on June 17, 2024, application number 202410773793.4, entitled "A back contact battery and its preparation method, photovoltaic module", the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] This application relates to the field of photovoltaic technology, and in particular to a back contact battery and its preparation method, and a photovoltaic module. Background Technology

[0004] Back-contact solar cells are solar cells with no electrodes on the light-facing side, and both the positive and negative electrodes are located on the back-facing side of the cell. This reduces the shading of the cells by the electrodes, increases the short-circuit current, and improves the energy conversion efficiency of the cells.

[0005] In the prior art, the back side of the back contact battery has an N-type doped layer and a P-type doped layer. The N-type doped layer and the P-type doped layer near the edge of the battery cell have a greater potential for defects and a higher risk of leakage. Summary of the Invention

[0006] The purpose of this application is to provide a back contact battery and its preparation method, as well as a photovoltaic module, to reduce the risk of leakage and minimize safety hazards.

[0007] To achieve the above objectives, this application provides the following technical solution:

[0008] A back-contact battery, comprising:

[0009] The substrate has a first surface and a second surface that are opposite each other.

[0010] A first doped layer and a second doped layer are alternately disposed on the first surface. The doping types of the first doped layer and the second doped layer are opposite, and the doping type of the second doped layer is the same as that of the substrate.

[0011] The substrate has an edge, and a first isolation region is formed between the boundary of the adjacent edge of the first doped layer and the edge, and a second isolation region is formed between the boundary of the adjacent edge of the second doped layer and the edge, wherein the width of at least a portion of the first isolation region is greater than the width of at least a portion of the second isolation region.

[0012] In the above technical solution, a first isolation region exists between the boundary of the adjacent edge of the first doped layer and the edge itself, and a second isolation region exists between the boundary of the adjacent edge of the second doped layer and the edge itself. Specifically, a local area of ​​the edge is adjacent to the boundary of the first doped layer, and the first isolation region separates the boundary of the adjacent edge of the first doped layer from the edge itself, in order to suppress leakage current. A local area of ​​the edge is adjacent to the boundary of the second doped layer, and the second isolation region separates the boundary of the adjacent edge of the second doped layer from the edge itself, in order to suppress leakage current.

[0013] The second doped layer has the same doping type as the substrate, while the first doped layer has the opposite doping type. Considering that a PN junction region is formed between the first doped layer with the opposite doping type and the substrate, the risk of leakage is greater. Therefore, the width of at least part of the first isolation region is greater than the width of at least part of the second isolation region, so as to set a wider first isolation region at the PN junction region formed between the first doped layer and the substrate, thereby reducing the risk of leakage and minimizing safety hazards.

[0014] In one implementation, the edge includes a first edge and a second edge that are set opposite to each other, wherein,

[0015] The back contact battery is a whole battery. The first surface is divided into two partitions by a dividing line perpendicular to the first edge and the second edge. In one partition, the width of the first isolation region formed between the boundary of the first doped layer and the first edge is greater than the width of the second isolation region formed between the boundary of the second doped layer and the second edge.

[0016] or,

[0017] The back contact cell is a half cell, and the width of the first isolation region formed between the boundary of the first doped layer and the first edge is greater than the width of the second isolation region formed between the boundary of the second doped layer and the second edge.

[0018] By adopting the above technical solution, regardless of whether the back contact battery is a whole cell or a half cell, a wider isolation width between the boundary of the first doped layer and the edge of the battery can be achieved, ensuring the stability and reliability of the back contact battery performance.

[0019] In one implementation, the edge includes a first edge and a second edge positioned opposite each other, and a third edge located between the first edge and the second edge, wherein,

[0020] The first doped layer and the second doped layer are arranged in an interdigitated pattern. The first doped layer includes a first connecting portion and a plurality of first interdigitated portions, and at least one first interdigitated portion is electrically connected to the first connecting portion. The second doped layer includes a second connecting portion and a plurality of second interdigitated portions, and at least one second interdigitated portion is electrically connected to the second connecting portion. The first connecting portion and the second connecting portion extend along the first edge and the second edge. The plurality of first interdigitated portions and the plurality of second interdigitated portions between the first connecting portion and the second connecting portion are arranged in multiple rows, and the multiple rows of first interdigitated portions and the multiple rows of second interdigitated portions are staggered.

[0021] The back-contact battery is a half-cell battery, and the width of the first isolation area formed between the first connecting portion and the first edge is greater than the width of the second isolation area formed between the second connecting portion and the second edge; or...

[0022] The back contact battery is a single battery. In one of the partitions, the width of the first isolation area formed between the first connecting part and the first edge is greater than the width of the second isolation area formed between the second connecting part and the second edge.

[0023] In one implementation, any row of first interdigitated fingers between the first connecting portion and the second connecting portion is continuous and uninterrupted, and any row of second interdigitated fingers between the first connecting portion and the second connecting portion is continuous and uninterrupted.

[0024] In one implementation, any row of first interdigitated fingers between the first connecting portion and the second connecting portion is discontinuously formed into multiple segments, and any row of second interdigitated fingers between the first connecting portion and the second connecting portion is discontinuously formed into multiple segments.

[0025] In one implementation, the third edge is adjacent to the boundary of the first interdigitated portion, and the isolation area near the first edge and the third edge can be processed continuously, which facilitates manufacturing and improves the processing efficiency of the back contact battery; or, the third edge is adjacent to the boundary of the second interdigitated portion, and the isolation area near the second edge and the third edge can be processed continuously, which facilitates manufacturing and improves the processing efficiency of the back contact battery.

[0026] In one implementation, one end of the third edge is connected to the end of the first edge by a first chamfer; the other end of the third edge is connected to the end of the second edge by a second chamfer; the boundary of the first doped layer is adjacent to the first chamfer, and the boundary of the second doped layer is adjacent to the second chamfer; this arrangement can reduce cracks at the corners of the silicon wafer and prevent the corners of the silicon wafer from cracking under external stress.

[0027] The boundary of the first doped layer adjacent to the first chamfer is a stepped edge; and / or, the boundary of the second doped layer adjacent to the second chamfer is an arc-shaped edge. For example, the first doped layer can be laser-modified first and then wet-etched to make the boundary of the first doped layer adjacent to the first chamfer a stepped edge. This ensures a larger width of the first isolation region between the first doped layer and the first chamfer, while the stepped edge can disperse stress, prevent stress concentration at the boundary of the first doped layer adjacent to the first chamfer, and reduce microcracks. In addition, the width of the second isolation region between the second doped layer and the second chamfer is smaller than the width of the first isolation region. For example, the second isolation region can be formed by wet etching only, with the boundary of the second doped layer adjacent to the second chamfer being an arc-shaped edge, to ensure maximum current collection and easier printing of gate lines onto the second doped layer.

[0028] And / or, the distance between the end of the second interdigitated portion near the first chamfer and the first connecting portion along the third edge direction is greater than the distance between the ends of the remaining second interdigitated portions and the first connecting portion along the third edge direction; and / or, the distance between the end of the first interdigitated portion near the second chamfer and the second connecting portion along the third edge direction is greater than the distance between the ends of the remaining first interdigitated portions and the second connecting portion along the third edge direction. Since the stress at the chamfer position of the battery cell is greater, making it more prone to microcracks, the distance d3 between the end of the second interdigitated portion near the first chamfer and the first connecting portion is made greater than the distance between the ends of the remaining second interdigitated portions and the first connecting portion, and the distance d4 between the end of the first interdigitated portion near the second chamfer and the second connecting portion is greater than the distance between the ends of the remaining first interdigitated portions and the second connecting portion, thus reducing defects such as microcracks in the first and second interdigitated portions.

[0029] In one implementation, one end of the third edge is connected to the end of the first edge by a first chamfer; the other end of the third edge is connected to the end of the second edge by a second chamfer.

[0030] In this configuration, the first interdigitated portion is adjacent to the third edge, and the distal edge of the first interdigitated portion near the second connecting portion is a bevel, which gradually slopes towards the second chamfer along the direction away from the third edge; or, the second interdigitated portion is adjacent to the third edge, and the distal edge of the second interdigitated portion near the first connecting portion is a bevel, which gradually slopes towards the first chamfer along the direction away from the third edge. This configuration ensures that the sharp corner of the bevel is far from the third edge, preventing stress concentration and microcracks at the sharp corner. It also allows for a larger area of ​​the first doped layer near the first chamfer or the second doped layer near the second chamfer, thus dispersing stress in the region of the first doped layer near the first chamfer or the region of the second doped layer near the second chamfer, preventing stress concentration and reducing the likelihood of microcracks.

[0031] In one implementation, the width of the portion of the first connecting part adjacent to the first edge is d1, and the width of the portion of the second connecting part adjacent to the second edge is d2, where d1 < d2.

[0032] In one implementation, 600μm≤d1≤800μm, 800μm≤d2≤1100μm.

[0033] In one implementation, the edge has a first edge and a second edge opposite to each other, and a third edge located between the first edge and the second edge;

[0034] The first doped layer includes a plurality of first strip-shaped portions extending along the third edge direction, and the second doped layer includes a plurality of second strip-shaped portions extending along the third edge direction. The plurality of first strip-shaped portions and the plurality of second strip-shaped portions are alternately and alternately arranged along the extension direction of the first edge or the second edge, and the two ends of the first strip-shaped portions and the second strip-shaped portions are respectively adjacent to the first edge and the second edge.

[0035] In one implementation, the boundary of the second strip is immediately adjacent to the third edge. The second doped layer being close to the third edge ensures better passivation of the cell edge. Conversely, if the first doped layer, opposite to the substrate, were close to the third edge, the recombination efficiency of the first doped layer at the third edge would be higher, but the minority carrier lifetime would be shorter, which is detrimental to improving photoelectric conversion efficiency.

[0036] In one implementation, the width of the first isolation region is 80μm-200μm; and / or, the width of the second isolation region is 10μm-50μm; and / or, the difference between the width of the first isolation region and the width of the second isolation region is greater than or equal to 30μm and less than or equal to 190μm. This is to prevent the risk of leakage from being too high due to excessively small distances between the first and second doped layers and the edges, while avoiding the reduction of effective power generation area and impact on power generation efficiency due to excessively large distances between the first and second doped layers and the edges.

[0037] In one implementation, the first isolation region and / or the second isolation region have a portion recessed into the substrate, and the side of the recessed portion away from the sidewall of the substrate forms an inclined portion that is inclined relative to the first surface, the angle between the inclined portion and the first surface being greater than or equal to 53° and less than or equal to 57°.

[0038] In one implementation, the first isolation region and / or the second isolation region have a recessed portion that extends into the substrate, and the bottom surface of the recessed portion forms a textured structure; the textured structure includes a pyramidal velvet structure. The pyramidal velvet structure on the bottom wall of the first isolation region and the second isolation region can increase the path length for moisture to enter the solar cell, reduce the entry of moisture, and thus prevent moisture from affecting the performance of the doped layer.

[0039] In one implementation, the substrate has a length and / or width of 166 μm-210 μm; and / or a thickness of 100 μm-170 μm; and / or a thickness of 150 nm-400 nm for the first and / or second doped layers; and / or a third isolation region with a width of 60 μm-200 μm is provided between the first and second doped layers. This ensures good field passivation while minimizing the poly thickness and reducing parasitic absorption.

[0040] A photovoltaic module includes at least two back-contact cells as described in any of the above embodiments and a plurality of electrical connectors, wherein the plurality of electrical connectors connect the at least two back-contact cells. Compared with the prior art, the beneficial effects of the photovoltaic module provided in this application are the same as the beneficial effects of the back-contact cells described above, and will not be repeated here.

[0041] In one implementation, the edge includes a first edge and a second edge disposed opposite to each other; the first doped layer and the second doped layer are arranged in a quasi-interdigital pattern, the first doped layer includes a first connecting portion and a plurality of first interdigital portions, at least one first interdigital portion being electrically connected to the first connecting portion; the second doped layer includes a second connecting portion and a plurality of second interdigital portions, at least one second interdigital portion being electrically connected to the second connecting portion; the first connecting portion and the second connecting portion extend along the first edge and the second edge, and the plurality of first interdigital portions and the plurality of second interdigital portions between adjacent first connecting portions and second connecting portions are arranged in multiple rows, with the multiple rows of first interdigital portions and the multiple rows of second interdigital portions being staggered and spaced apart;

[0042] The back contact battery is a half-cell battery, with the first connecting part adjacent to the first edge and the second connecting part adjacent to the second edge;

[0043] Multiple electrical connectors and the first connection portions of the first doped layer and / or the second connection portions of the second doped layer adjacent to the first edge and / or the second edge do not overlap on the orthogonal projection onto the back contact cell. Thus, the electrical connectors are offset from the first and second connection portions near the first and / or second edges, preventing damage to these portions, ensuring efficient collection of the first and second connection portions near the first and / or second edges, and further improving electrical isolation.

[0044] A method for preparing a back contact battery, comprising:

[0045] A substrate is provided, the substrate having opposing first and second surfaces, the first surface having an edge, and the first surface having a first doped layer and a second doped layer, and a third region between the first doped layer and the second doped layer;

[0046] A first doped layer is formed and patterned on a first surface of the substrate, the doping type of the first doped layer being opposite to that of the substrate;

[0047] A second doped layer is formed and patterned on the first surface of the substrate, wherein the doping type of the second doped layer is opposite to that of the first doped layer.

[0048] When patterning the first doped layer or the second doped layer, a first isolation region is formed that penetrates the first doped layer along the thickness direction of the substrate, the first isolation region separating the first doped layer from the edge; and a second isolation region is formed that penetrates the second doped layer along the thickness direction of the substrate, the second isolation region separating the second doped layer from the edge, and the width of the first isolation region is greater than the width of the second isolation region.

[0049] Compared with the prior art, the beneficial effects of the method for manufacturing the back contact battery provided in this application embodiment are the same as the beneficial effects of the back contact battery described above, and will not be repeated here.

[0050] In one implementation, the step of forming a first isolation region penetrating the first doped layer along the thickness direction of the substrate includes: firstly, irradiating the portion of the first doped layer at the corresponding position of the first isolation region with a laser, and then forming the first isolation region penetrating the first doped layer along the thickness direction of the substrate by etching with an etchant.

[0051] The step of forming a second isolation region that penetrates the second doped layer along the thickness direction of the substrate includes: forming the second isolation region that penetrates the second doped layer along the thickness direction of the substrate by etching with an etchant.

[0052] In one implementation, forming a first isolation region penetrating the first doped layer along the thickness direction of the substrate includes: forming a portion of the first isolation region recessed into the substrate, the bottom surface of the recessed portion forming a textured structure; the textured structure includes a pyramid-shaped velvet structure;

[0053] Forming a second isolation region penetrating the second doped layer along the thickness direction of the substrate includes: forming a portion of the second isolation region recessed into the substrate, the bottom surface of which forms a textured structure; the textured structure includes a pyramid-shaped textured structure. The bottom walls of the first and second isolation regions are pyramid-shaped textured structures, which can increase the path length for water vapor to enter the solar cell, reduce the entry of water vapor, and thus prevent water vapor from affecting the performance of the doped layer. Attached Figure Description

[0054] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0055] Figure 1 is a schematic diagram of the back contact battery provided in an embodiment of this application;

[0056] Figure 2 is a partial schematic diagram of the first surface of the back contact battery provided in an embodiment of this application;

[0057] Figure 3 is a magnified view of a portion of region A in Figure 2;

[0058] Figure 4 is a magnified view of region B in Figure 2;

[0059] Figure 5 is a partial cross-sectional view along CC in Figure 2 provided in an embodiment of this application;

[0060] Figure 6 is a schematic diagram of a portion of the first surface of the back contact battery according to another embodiment of this application.

[0061] Reference numerals: 1-First edge, 2-Second edge, 3-First doped layer, 3a-Stepped edge, 4-Second doped layer, 4a-Bevel, 4b-Arc edge, 5-Third edge, 6-First isolation region, 7-First chamfer, 8-Third isolation region, 9-Second isolation region, 10-Second chamfer, 11-Passivation layer, 12-Substrate. Detailed Implementation

[0062] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0063] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0064] Furthermore, 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 number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0065] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0066] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0067] The most significant characteristic of back-contact batteries is that all metal contacts are located on the back of the battery, eliminating the obstruction of metal electrodes on the front. This results in a higher short-circuit current (Isc), and the back allows for wider metal grid lines to reduce series resistance (Rs), thereby improving the fill factor (FF). Furthermore, this type of battery, with its unobstructed front, not only boasts high conversion efficiency but also a more aesthetically pleasing appearance. Additionally, the all-back electrode assembly is easier to assemble. IBC batteries represent one of the current technological directions for achieving high-efficiency crystalline silicon solar cells.

[0068] Specifically, as shown in Figure 5, a back-contact battery typically includes a substrate 12, a first doped layer 3, and a second doped layer 4. The substrate 12 has opposing first and second surfaces, with the second surface being the light-facing surface of the back-contact battery and the first surface being the back-facing surface. The first doped layer 3 and the second doped layer 4 are alternately disposed on the first surface of the substrate 12. The first doped layer 3 and the second doped layer 4 have opposite doping types to collect and export electrons and holes, respectively, to form a photocurrent.

[0069] The substrate 12 has an edge that surrounds its perimeter. This edge can be understood to include closed patterns such as polygonal rings, square rings, rounded square rings, and circular rings. A first isolation region 6 exists between the boundary of the first doped layer 3 and its adjacent edge, and a second isolation region 9 exists between the boundary of the second doped layer 4 and its adjacent edge. Specifically, where a portion of the edge is adjacent to the boundary of the first doped layer 3, the first isolation region 6 separates the boundary of the first doped layer 3 from the edge to suppress leakage current. Similarly, where a portion of the edge is adjacent to the boundary of the second doped layer 4, the second isolation region 9 separates the boundary of the second doped layer 4 from the edge to suppress leakage current.

[0070] The so-called isolation regions (first isolation region 6 and second isolation region 9) are regions where electron / hole collection does not occur. They do not contribute current, or there is no doped layer in these regions, and therefore no photocurrent is generated or collected. These isolation regions separate the boundaries of the doped layers (first doped layer 3 and second doped layer 4) from the edge of the substrate 12 to ensure electrical insulation.

[0071] The second doped layer 4 has the same doping type as the substrate 12, while the first doped layer 3 has the opposite doping type to the substrate 12. Considering that a PN junction region is formed between the first doped layer 3 with the opposite doping type and the substrate 12, the risk of leakage is greater. Therefore, the width of at least a portion of the first isolation region 6 is greater than the width of at least a portion of the second isolation region 9. That is, the width of all the first isolation regions 6 can be greater than the width of all the second isolation regions 9, or the width of a local first isolation region 6 can be greater than the width of a local second isolation region 9. In order to set a wider first isolation region 6 at the PN junction region formed between the first doped layer 3 and the substrate 12, the risk of leakage is reduced and safety hazards are reduced.

[0072] The substrate 12 is a semiconductor substrate. The material of the substrate 12 can be silicon (Si), germanium (Ge), gallium arsenide (GaAs), or similar materials. Obviously, in terms of conductivity type, the substrate 12 can be an intrinsically conductive substrate, an n-type conductive substrate, or a p-type conductive substrate. Preferably, the substrate 12 is a p-type conductive substrate or an n-type conductive substrate. Compared to an intrinsically conductive substrate, a p-type conductive substrate or an n-type conductive substrate has better conductivity, resulting in a lower bulk resistivity in the final back contact battery, thereby improving the efficiency of the back contact battery.

[0073] For example, substrate 12 is an n-type silicon substrate. Compared with p-type conductive substrates, n-type silicon substrates have advantages such as high minority carrier lifetime, no light decay, and good performance in low light.

[0074] The first doped layer 3 and the second doped layer 4 are both semiconductor doped layers. Regarding their internal arrangement, the first doped layer 3 and the second doped layer 4 can be amorphous, microcrystalline, single-crystal, nanocrystalline, or polycrystalline, etc. They can be additionally formed on the substrate 12 by deposition techniques, or formed within the substrate 12 by in-situ doping methods such as ion implantation. Specifically, the materials of the first doped layer 3 and the second doped layer 4 can be silicon (Si), germanium (Ge), silicon carbide (SiCx), or gallium arsenide (GaAs), etc. Regarding their conductivity type, the first doped layer 3 and the second doped layer 4 can be n-type or p-type doped layers.

[0075] In some examples, when the substrate 12 is an n-type substrate, the first doped layer 3 can be a p-type doped layer and the second doped layer 4 can be an n-type doped layer; or, when the substrate 12 is a p-type substrate, the first doped layer 3 can be an n-type doped layer and the second doped layer 4 can be a p-type doped layer.

[0076] For example, the substrate 12 is an n-type silicon substrate, the first doped layer 3 is a boron-doped p-type doped layer, and the second doped layer 4 is a phosphorus-doped n-type doped layer. In this case, since the heavily phosphorus-doped region has greater solubility for metal impurities, the phosphorus in the second doped layer 4 can provide phosphorus getter passivation for the first doped layer 3, thereby improving battery efficiency.

[0077] In some specific embodiments, as shown in FIG2, the edges have opposing first edges 1 and second edges 2, that is, the first edges 1 and the second edges 2 are parallel to each other and are located on opposite sides of the first surface. A first isolation region 6 is provided between the first doped layer 3 and the first edge 1 or the second edge 2 adjacent thereto, and a second isolation region 9 is provided between the second doped layer 4 and the first edge 1 or the second edge 2 adjacent thereto. Specifically, the first edge 1 may be adjacent only to the first doped layer 3, in which case the first isolation region 6 is provided between the first edge 1 and the first doped layer 3; or, the first edge 1 may be adjacent only to the second doped layer 4, in which case the second isolation region 9 is provided between the first edge 1 and the second doped layer 4; or, a part of the first edge 1 is adjacent to the first doped layer 3 and another part is adjacent to the second doped layer 4, in which case the first isolation region 6 is provided between a part of the first edge 1 and the first doped layer 3 and the second isolation region 9 is provided between the other part of the first edge 1 and the second doped layer 4. Similarly, the second edge 2 may be adjacent only to the first doped layer 3, in which case a first isolation region 6 is provided between the second edge 2 and the first doped layer 3; or, the second edge 2 may be adjacent only to the second doped layer 4, in which case a second isolation region 9 is provided between the second edge 2 and the second doped layer 4; or, a portion of the second edge 2 may be adjacent to the first doped layer 3 and another portion may be adjacent to the second doped layer 4, in which case a first isolation region 6 is provided between a portion of the second edge 2 and the first doped layer 3 and a second isolation region 9 is provided between the other portion of the second edge 2 and the second doped layer 4.

[0078] In some embodiments, the width of the second isolation region 9 can be close to 0. The second isolation region 9 can be formed without deliberately removing it by means of etching or other means. Instead, it is formed by the natural side etching of the second doped layer 4 at the edge by the etching solution, thereby removing a small amount of the edge position of the second doped layer 4 to form the second isolation region 9. In this embodiment, the width of the second isolation region 9 near the corner (i.e., the chamfer and the right angle position of the half-cell cut below) can be greater than 0, while the width of the second isolation region 9 away from the corner can be basically 0.

[0079] Furthermore, the first surface also has a third edge 5 located between the first edge 1 and the second edge 2, and the third edge 5 may be perpendicular to the first edge 1 and the second edge 2. In this embodiment, as shown in FIG6, the third edge 5 may be adjacent to the boundary of the first doped layer 3, and a first isolation region 6 is provided between the boundary of the first doped layer 3 and the third edge 5; or, as shown in FIG2, the third edge 5 may be adjacent to the boundary of the second doped layer 4, and a second isolation region 9 is provided between the boundary of the second doped layer 4 and the third edge 5. In this technical solution, the boundary of the first doped layer 3 or the second doped layer 4 can be separated from the third edge 5 to facilitate the suppression of leakage current.

[0080] As shown in Figure 1, the back contact battery can be a full cell. As shown in Figures 2 and 6, the back contact battery can also be a half cell.

[0081] When the back-contact battery is a single cell, the first surface is divided into two partitions by a dividing line perpendicular to the first edge 1 and the second edge 2. In one partition, the width of the first isolation region 6 formed between the boundary of the first doped layer 3 and the first edge 1 is greater than the width of the second isolation region 9 formed between the boundary of the second doped layer 4 and the second edge 2. The type of doped layer adjacent to the first edge 1 and the second edge 2 in the other partition is not specifically limited. For example, in another partition, the second isolation region 9 can be formed between the boundary of the second doped layer 4 and the first edge 1, and the first isolation region 6 can be formed between the boundary of the first doped layer 3 and the second edge 2. Alternatively, in both partitions, the first isolation region 6 can be formed between the boundary of the first doped layer 3 and the first edge 1, and the second isolation region 9 can be formed between the boundary of the second doped layer 4 and the second edge 2; or, in both partitions, the first isolation region 6 can be formed between the boundary of the first doped layer 3 and the second edge 2, and the second isolation region 9 can be formed between the boundary of the second doped layer 4 and the first edge 1. Specifically, the two partitions divided by the dividing line on the first surface are the first partition and the second partition.

[0082] When the back contact battery is a single cell, for example, the first edge 1 is only adjacent to the boundary of the first connecting portion, and a first isolation region 6 is formed between the first edge 1 and the boundary of the first connecting portion; and the second edge 2 is only adjacent to the boundary of the second connecting portion, and a second isolation region 9 is formed between the second edge 2 and the boundary of the second connecting portion. In this embodiment, the third edge 5 may be adjacent to the boundary of the first interdigitated portion, and a first isolation region 6 is formed between the third edge 5 and the boundary of the first interdigitated portion; or the third edge 5 may be adjacent to the boundary of the second interdigitated portion, and a second isolation region 9 is formed between the third edge 5 and the boundary of the second interdigitated portion.

[0083] Alternatively, the first edge 1 may be adjacent only to the boundary of the second connecting portion, and a second isolation zone 9 may be formed between the first edge 1 and the boundary of the second connecting portion. The second edge 2 may be adjacent only to the boundary of the first connecting portion, and a first isolation zone 6 may be formed between the second edge 2 and the boundary of the first connecting portion. In this embodiment, the third edge 5 may be adjacent only to the boundary of the first interdigitated portion, and a first isolation zone 6 may be formed between the third edge 5 and the boundary of the first interdigitated portion; or the third edge 5 may be adjacent only to the boundary of the second interdigitated portion, and a second isolation zone 9 may be formed between the third edge 5 and the boundary of the second interdigitated portion.

[0084] In the two embodiments described above, the first doped layer 3, the second doped layer 4, the first isolation region 6, and the second isolation region 9 within the two partitions can be symmetrically arranged relative to the dividing line to facilitate processing and manufacturing.

[0085] When the back contact battery is a single cell, for example, the first edge 1 in the first partition is adjacent to the boundary of the first connecting portion, and a first isolation region 6 is formed between the first edge 1 and the boundary of the first connecting portion. The first edge 1 in the second partition is adjacent to the boundary of the second connecting portion, and a second isolation region 9 is formed between the first edge 1 and the boundary of the second connecting portion. The second edge 2 in the first partition is adjacent to the boundary of the second connecting portion, and a second isolation region 9 is formed between the second edge 2 and the boundary of the second connecting portion. The second edge 2 in the second partition is adjacent to the boundary of the first connecting portion, and a first isolation region 6 is formed between the second edge 2 and the boundary of the first connecting portion. In this embodiment, the third edge 5 may be adjacent to the boundary of the first interdigitated portion, and a first isolation region 6 may be formed between the third edge 5 and the boundary of the first interdigitated portion; or the third edge 5 may be adjacent to the boundary of the second interdigitated portion, and a second isolation region 9 may be formed between the third edge 5 and the boundary of the second interdigitated portion.

[0086] Alternatively, the first edge 1 within the first partition is adjacent to the boundary of the second connecting portion, and a second isolation zone 9 is formed between the first edge 1 and the boundary of the second connecting portion. The first edge 1 within the second partition is adjacent to the boundary of the first connecting portion, and a first isolation zone 6 is formed between the first edge 1 and the boundary of the first connecting portion. The second edge 2 within the first partition is adjacent to the boundary of the first connecting portion, and a first isolation zone 6 is formed between the second edge 2 and the boundary of the first connecting portion. The second edge 2 within the second partition is adjacent to the boundary of the second connecting portion, and a second isolation zone 9 is formed between the second edge 2 and the boundary of the second connecting portion. In this embodiment, the third edge 5 may be adjacent to the boundary of the first interdigitated portion, and a first isolation zone 6 is formed between the third edge 5 and the boundary of the first interdigitated portion; or the third edge 5 may be adjacent to the boundary of the second interdigitated portion, and a second isolation zone 9 is formed between the third edge 5 and the boundary of the second interdigitated portion.

[0087] In the two embodiments described above, the first doped layer 3, the second doped layer 4, the first isolation region 6, and the second isolation region 9 within the two partitions can be symmetrically arranged with respect to the center of the partition line to facilitate processing and manufacturing.

[0088] In another embodiment, when the back contact battery is a half-cell battery, for example, the first edge 1 is adjacent to the boundary of the first doped layer 3, and a first isolation region 6 is formed between the boundary of the first doped layer 3 and the first edge 1; the second edge 2 is adjacent to the boundary of the second doped layer 4, and a second isolation region 9 is formed between the boundary of the second doped layer 4 and the second edge 2. Alternatively, the first edge 1 may be adjacent to the boundary of the second doped layer 4, and a second isolation region 9 may be formed between the boundary of the second doped layer 4 and the first edge 1; the second edge 2 may be adjacent to the boundary of the first doped layer 3, and a first isolation region 6 may be formed between the boundary of the first doped layer 3 and the second edge 2. In this embodiment, the third edge 5 may be adjacent to the boundary of the first interdigitated portion, and a first isolation region 6 may be formed between the third edge 5 and the boundary of the first interdigitated portion; or the third edge 5 may be adjacent to the boundary of the second interdigitated portion, and a second isolation region 9 may be formed between the third edge 5 and the boundary of the second interdigitated portion.

[0089] By adopting the above technical solution, regardless of whether the back contact battery is a whole cell or a half cell, a larger isolation width can be achieved between the boundary of the first doped layer 3 and the edge of the battery, thus ensuring the stability and reliability of the back contact battery performance.

[0090] It should be noted that in the process of manufacturing a half-cell battery, a full cell can be formed first, and then the full cell can be cut into two half-cell batteries. Alternatively, a silicon wafer can be cut into half-wafers first, and then the half-wafers can be processed to finally form a half-cell battery. It is understood that the technology of this application is also applicable to three-part, four-part, five-part, six-part, and more-part sub-cells, all of which involve dividing a rectangular sheet into multiple sub-cells, either equally or unequally. These sub-cells can be rectangular in shape. For example, for a 210mm*210mm rectangular sheet, the size of a half-cell battery is 105mm*210mm, while the size of each sub-cell of a three-part sheet is 70mm*210mm, and so on, resulting in even more sub-cells.

[0091] In another specific embodiment, the first doped layer 3 and the second doped layer 4 are arranged in an interdigitated pattern. The first doped layer 3 includes a first connecting portion and a plurality of first interdigitated portions, at least one of the first interdigitated portions being electrically connected to the first connecting portion. The second doped layer 4 includes a second connecting portion and a plurality of second interdigitated portions, at least one of the second interdigitated portions being electrically connected to the second connecting portion. The first connecting portion and the second connecting portion extend along the first edge and the second edge, and the plurality of first interdigitated portions and the plurality of second interdigitated portions between the first connecting portion and the second connecting portion are arranged in multiple rows, that is, the plurality of first interdigitated portions and the plurality of second interdigitated portions between the first connecting portion or the second connecting portion adjacent to the first edge 1 and the first connecting portion or the second connecting portion adjacent to the second edge 2 are arranged in multiple rows. The multiple rows of first interdigitated portions and the multiple rows of second interdigitated portions are staggered and spaced apart.

[0092] In one example, any row of first interdigitated fingers between the first connecting portion and the second connecting portion is continuous and uninterrupted, and any row of second interdigitated fingers between the first connecting portion and the second connecting portion is continuous and uninterrupted. Each row of first interdigitated fingers between the first connecting portion and the second connecting portion is connected to the first connecting portion, and each row of second interdigitated fingers between the first connecting portion and the second connecting portion is connected to the second connecting portion. In this example, there can be multiple first connecting portions and multiple second connecting portions, arranged alternately along the extension direction of the third edge 5. In this example, along the extension direction of the third edge 5, any row of first interdigitated fingers can be interrupted by a second connecting portion not immediately adjacent to the first edge and the second edge, and any row of second interdigitated fingers can be interrupted by a first connecting portion not immediately adjacent to the first edge 1 and the second edge 2. However, any row of first interdigitated fingers between adjacent first connecting portions and second connecting portions is continuous and uninterrupted, and any row of second interdigitated fingers between adjacent first connecting portions and second connecting portions is continuous and uninterrupted. Any row of first interdigitated fingers between adjacent first and second connecting parts is connected to the first connecting part, and any row of second interdigitated fingers between adjacent first and second connecting parts is connected to the second connecting part.

[0093] In another example, any row of first interdigitated fingers between the first connecting portion and the second connecting portion is discontinuously segmented into multiple segments, and any row of second interdigitated fingers between the first connecting portion and the second connecting portion is also discontinuously segmented into multiple segments. In this example, there is one first connecting portion and one second connecting portion. There may be at least one third connecting portion or no other connecting portion between the first connecting portion and the second connecting portion. The first connecting portion and the second connecting portion are respectively disposed adjacent to the first edge and the second edge. Any row of first interdigitated fingers between the first connecting portion and the second connecting portion is a discontinuous multiple segment, and any row of second interdigitated fingers between the first connecting portion and the second connecting portion is a discontinuous multiple segment.

[0094] In the above technical solution, as shown in Figures 2 and 6, the back contact battery is a half-cell battery, the first connecting part is adjacent to the first edge 1, and the second connecting part is adjacent to the second edge 2.

[0095] In the above technical solution, as shown in Figure 1, the back contact battery is a whole battery. In one partition, the first connecting part is adjacent to the first edge 1 and the second connecting part is adjacent to the second edge 2. In another partition, the second connecting part is adjacent to the first edge 1 and the first connecting part is adjacent to the second edge 2. Alternatively, in both partitions, the boundary of the first doped layer 3 is adjacent to the first edge 1 and the boundary of the second doped layer 4 is adjacent to the second edge 2. Alternatively, in both partitions, the boundary of the first doped layer 3 is adjacent to the second edge 2 and the boundary of the second doped layer 4 is adjacent to the first edge 1.

[0096] Specifically, both the first connecting portion and the second connecting portion extend in a direction parallel to the first edge 1, and both the first interdigitated portion and the second interdigitated portion extend in a direction perpendicular to the first edge 1. The first edge 1 may be adjacent only to the boundary of the first connecting portion, or the first edge 1 may be adjacent only to the boundary of the second connecting portion, or a portion of the first edge 1 may be adjacent to the boundary of the first connecting portion and another portion of the first edge 1 may be adjacent to the boundary of the second connecting portion. Similarly, the second edge 2 may be adjacent only to the boundary of the first connecting portion, or the second edge 2 may be adjacent only to the boundary of the second connecting portion, or a portion of the second edge 2 may be adjacent to the boundary of the first connecting portion and another portion of the first edge 1 may be adjacent to the boundary of the second connecting portion. Furthermore, a first isolation zone 6 is provided between the first connecting portion and its adjacent first edge 1 or second edge 2, and a second isolation zone 9 is provided between the second connecting portion and its adjacent first edge 1 or second edge 2.

[0097] By adopting the above technical solution, the first isolation zone 6 or the second isolation zone 9 extends in a direction parallel to the first edge 1 and the second edge 2, which is conducive to the formation of the first isolation zone 6 and the second isolation zone 9.

[0098] It should be noted that in the above embodiments, a first isolation zone is provided between the first connecting portion and the edge and / or between the first interdigitated portion and the edge; a second isolation zone is provided between the second connecting portion and the edge and / or between the second interdigitated portion and the edge.

[0099] Since the third edge 5 can be perpendicular to the first edge 1 and the second edge 2, the third edge 5 can be adjacent to the boundary of the first interdigitated portion, and the first edge 1 can be adjacent to the boundary of the first connecting portion. With this technical solution, the isolation area near the third edge 5 is the same as the isolation area near the first edge 1. The isolation areas near the first edge 1 and the third edge 5 can be processed continuously, facilitating manufacturing and improving the processing efficiency of the back contact battery. Alternatively, the third edge 5 can be adjacent to the boundary of the second interdigitated portion, and the second edge 2 can be adjacent to the boundary of the second connecting portion. With this technical solution, the isolation area near the third edge 5 is the same as the isolation area near the second edge 2. The isolation areas near the third edge 5 and the second edge 2 can be processed continuously, facilitating manufacturing and improving the processing efficiency of the back contact battery.

[0100] As shown in Figure 2, one end of the third edge 5 is connected to the end of the first edge 1 by a first chamfer 7; the other end of the third edge 5 is connected to the end of the second edge 2 by a second chamfer 10. This arrangement can reduce cracks at the corners of the silicon wafer and prevent the corners from cracking under external stress.

[0101] Furthermore, as shown in Figure 2, the boundary of the first doped layer 3 is adjacent to the first chamfer 7, and the boundary of the second doped layer 4 is adjacent to the second chamfer 10. Since the stress at the chamfer position of the solar cell is relatively high, it is more prone to microcracks. If the doped layer is too close to the chamfer (first chamfer 7 and second chamfer 10), the microcracks in the solar cell will be transmitted to the doped layer, leading to defects in the doped layer. Therefore, an isolation region needs to be set between the chamfer and the doped layer. For the first doped layer 3, laser modification followed by wet etching is required to make the boundary of the first doped layer 3 adjacent to the first chamfer 7 a stepped edge 3a. This ensures a larger width of the first isolation region 6 between the first doped layer 3 and the first chamfer 7, while the stepped edge 3a can disperse stress, preventing stress concentration at the boundary of the first doped layer 3 adjacent to the first chamfer 7 and reducing microcracks. Furthermore, the width of the second isolation region 9 between the second doped layer 4 and the second chamfer 10 is smaller than the width of the first isolation region 6. The second isolation region 9 can be formed by wet etching. The boundary of the second doped layer 4 adjacent to the second chamfer 10 is an arc-shaped edge 4b ​​to ensure maximum current collection and make it easier to print the gate line onto the second doped layer 4.

[0102] A third isolation region 8 is provided between the first doped layer 3 and the second doped layer 4 to avoid leakage of the back contact battery and to improve the reliability of the battery in later products. The width of the third isolation region 8 can be 60μm-200μm. For example, the width of the third isolation region 8 is 60μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm or 200μm.

[0103] As shown in Figure 3, the chamfered area of ​​the battery cell experiences higher stress, making it more prone to microcracks. If the second interdigitated portion is too close to the first chamfer 7, the microcracks will propagate to the second interdigitated portion, leading to defects. Therefore, the distance d3 between the end of the second interdigitated portion near the first chamfer 7 and the first connecting portion along the third edge is made greater than the distance between the ends of the other second interdigitated portions and the first connecting portion along the third edge 5. In other words, the distance between the end of the second interdigitated portion near the first chamfer 7 and the first connecting portion along the third edge 5 is larger, thus increasing the distance between the end of the second interdigitated portion and the first chamfer 7 and reducing defects such as microcracks in the second interdigitated portion. There can be one or more second interdigitated portions near the first chamfer 7.

[0104] As shown in Figure 4, considering that the stress at the chamfered position of the solar cell is greater and more prone to microcracks, if the first interdigitated part is too close to the second chamfer 10, the microcracks in the solar cell will be transmitted to the first interdigitated part, resulting in defects in the first interdigitated part. Therefore, the distance d4 between the end of the first interdigitated part near the second chamfer 10 and the second connecting part along the third edge extension direction is made greater than the distance between the ends of the other first interdigitated parts and the second connecting part along the third edge extension direction. That is, the distance between the end of the first interdigitated part near the second chamfer 10 and the second connecting part along the third edge 5 extension direction is larger, so that the end of the first interdigitated part is farther from the second chamfer 10, reducing defects such as microcracks in the first interdigitated part. Here, the first interdigitated part near the second chamfer 10 can be one or more.

[0105] Furthermore, the end edge of the interdigitated portion (first interdigitated portion and second interdigitated portion) adjacent to the third edge 5, which has the opposite polarity to the connecting portion (first connecting portion and second connecting portion) adjacent to the first edge 1, is a bevel 4a, and the bevel 4a gradually slopes towards the first chamfer 7 along the direction away from the third edge 5.

[0106] As shown in Figures 2 and 3, when the boundary of the first doped layer 3 is adjacent to the first chamfer 7, the second interdigitated portion is adjacent to the third edge 5. The end edge of the second interdigitated portion near the first connecting portion is a bevel 4a, and the bevel 4a gradually slopes towards the first chamfer 7 along the direction away from the third edge 5. The aforementioned second interdigitated portion near the first connecting portion refers to the second interdigitated portion that is close to the first connecting portion adjacent to the first edge or the second edge. With this configuration, the sharp corner of the bevel 4a is far from the third edge 5, which can prevent stress concentration at the sharp corner of the bevel 4a and the occurrence of microcracks. At the same time, it can make the area of ​​the first doped layer 3 near the first chamfer 7 larger, which can disperse the stress in the region of the first doped layer 3 near the first chamfer 7, prevent stress concentration in the region of the first doped layer 3 near the first chamfer 7, and reduce the occurrence of microcracks.

[0107] Alternatively, when the boundary of the second doped layer 4 is adjacent to the second chamfer 10, the first interdigitated portion is adjacent to the third edge 5, and the distal edge of the first interdigitated portion near the second connecting portion is a bevel 4a, which gradually slopes towards the second chamfer 10 along the direction away from the third edge 5. The aforementioned first interdigitated portion near the second connecting portion refers to the first interdigitated portion adjacent to the second connecting portion that is adjacent to the first or second edge. With this configuration, the sharp corner of the bevel 4a is far from the third edge 5, which can prevent stress concentration at the sharp corner of the bevel 4a and the resulting microcracks. Simultaneously, it allows the second doped layer 4 to have a larger area near the second chamfer 10, which can disperse the stress in the region of the second doped layer 4 near the second chamfer 10, preventing stress concentration and reducing the likelihood of microcracks.

[0108] In another preferred embodiment, as shown in Figures 3 and 4, the width d1 of the portion of the first connecting part adjacent to the first edge 1 is less than the width d2 of the portion of the second connecting part adjacent to the second edge 2. That is, the width of the portion of the first connecting part adjacent to the first edge 1 is d1, and the width of the portion of the second connecting part adjacent to the second edge 2 is d2, where d1 < d2. Specifically, in the region near the first edge 1 and the second edge 2, the width d1 of the first connecting part is less than the width d2 of the second connecting part.

[0109] Furthermore, 600μm ≤ d1 ≤ 800μm. For example, the width d1 of the portion of the first connecting part adjacent to the first edge 1 can be 600μm, 620μm, 650μm, 680μm, 700μm, 720μm, 750μm, 780μm, or 800μm. Additionally, 800μm ≤ d2 ≤ 1100μm. For example, the width d2 of the portion of the second connecting part adjacent to the second edge 2 can be 800μm, 850μm, 900μm, 950μm, 1000μm, 1050μm, or 1100μm.

[0110] In another embodiment, the edge has a first edge 1 and a second edge 2 opposite to each other, and a third edge 5 located between the first edge 1 and the second edge 2. The third edge 5 may be perpendicular to the first edge 1 and the second edge 2. The first doped layer 3 includes a plurality of first strip-shaped portions extending along the direction of the third edge 5, and the second doped layer 4 includes a plurality of second strip-shaped portions extending along the direction of the third edge 5. The plurality of first strip-shaped portions and the plurality of second strip-shaped portions are alternately arranged along the extension direction of the first edge or the second edge, and the two ends of the first strip-shaped portions and the second strip-shaped portions are respectively adjacent to the first edge and the second edge. In this embodiment, a first isolation region 6 is provided between the first strip-shaped portion and the edge, and a second isolation region 9 is provided between the second strip-shaped portion and the edge. In this embodiment, the boundary of the second strip-shaped portion is adjacent to the third edge, and the second doped layer 4 is close to the third edge 5, which can ensure better passivation of the cell edge. However, if the first doped layer 3 opposite to the substrate 12 is close to the third edge 5, the recombination efficiency of the first doped layer 3 at the position of the third edge 5 is greater, the cell life is shorter, and it is not conducive to improving the photoelectric conversion efficiency. It should be noted that in this embodiment, the back contact battery can be a full cell or a half cell.

[0111] In the above embodiments, since the stress at the chamfered position of the battery cell is greater, it is more prone to microcracks. If the strip-shaped portions (the first strip-shaped portion and the second strip-shaped portion) are too close to the first chamfer 7, the microcracks in the battery cell will be transmitted to the strip-shaped portions, resulting in defects in the strip-shaped portions. Therefore, the distance between the end of the first strip-shaped portion near the first chamfer 7 and the first edge 1 along the direction of the third edge 5 is greater than the distance between the end of the remaining first strip-shaped portions and the first edge 1 along the direction of the third edge 5. The distance between the end of the second strip-shaped portion near the first chamfer 7 and the first edge 1 along the direction of the third edge 5 is greater than the distance between the end of the remaining second strip-shaped portions and the first edge 1 along the direction of the third edge 5. That is, the distance between the end of the strip-shaped portion near the first chamfer 7 and the first edge 1 along the direction of the third edge 5 is larger, making the end of the strip-shaped portion farther from the first chamfer 7, reducing defects such as microcracks in the strip-shaped portions. The first strip-shaped portion and the second strip-shaped portion near the first chamfer 7 can be one or more.

[0112] In the above embodiments, since the stress at the chamfered position of the battery cell is greater, it is more prone to microcracks. If the strip-shaped portions (the first strip-shaped portion and the second strip-shaped portion) are too close to the second chamfer 10, the microcracks in the battery cell will be transmitted to the strip-shaped portions, resulting in defects in the strip-shaped portions. Therefore, the distance between the end of the first strip-shaped portion near the second chamfer 10 and the second edge 2 along the direction of the third edge 5 is greater than the distance between the end of the remaining first strip-shaped portions and the second edge 2 along the direction of the third edge 5. The distance between the end of the second strip-shaped portion near the second chamfer 10 and the second edge 2 along the direction of the third edge 5 is greater than the distance between the end of the remaining second strip-shaped portions and the second edge 2 along the direction of the third edge 5. That is, the distance between the end of the strip-shaped portion near the second chamfer 10 and the second edge 2 along the direction of the third edge 5 is larger, making the end of the strip-shaped portion farther from the second chamfer 10, reducing defects such as microcracks in the strip-shaped portions. The first strip-shaped portion and the second strip-shaped portion near the second chamfer 10 can be one or more.

[0113] In the above embodiments, the width of the first isolation region 6 is 80μm-200μm. In this embodiment, the first isolation region 6 is set within a reasonable range to prevent the risk of leakage from being too high due to an excessively small distance between the first doped layer 3 and the edge, while also avoiding an excessively large distance between the first doped layer 3 and the edge, which would reduce the effective power generation area and affect power generation efficiency. For example, the width of the first isolation region 6 is 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm, 170μm, 180μm, 190μm, or 200μm.

[0114] The width of the second isolation region 9 is 10μm-50μm. Setting the second isolation region 9 within a reasonable range prevents the distance between the second doped layer 4 and the edge from being too small, resulting in higher carrier recombination efficiency at the battery edge, and avoids the distance between the second doped layer 4 and the edge being too large, which would reduce the effective power generation area and affect power generation efficiency. For example, the width of the second isolation region 9 is 10μm, 20μm, 30μm, 40μm, or 50μm.

[0115] In some embodiments, the width of the second isolation region 9 may be close to 0, the second doped layer 4 reaches the second edge 2, and may extend to the side of the semiconductor layer substrate. Alternatively, during the patterning of the second doped layer 4, the second doped layer 4 at the substrate edge may be naturally etched by the etching solution to form a second isolation region 9 slightly larger than 0. In this embodiment, the width of the second isolation region 9 may be 0-50 μm.

[0116] Preferably, the difference between the width of the first isolation region 6 and the width of the second isolation region 9 is greater than or equal to 30 μm and less than or equal to 190 μm, that is, the width of the first isolation region 6 is 30 μm-190 μm larger than the width of the second isolation region 9. This prevents the difference between the widths of the first isolation region 6 and the second isolation region 9 from being too large, which would result in a large difference between the total area of ​​the first doped layer 3 and the total area of ​​the second doped layer 4, affecting power generation efficiency. For example, the difference between the width of the first isolation region 6 and the width of the second isolation region 9 can be 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, or 190 μm.

[0117] As shown in Figure 5, the first isolation region 6 and / or the second isolation region 9 have a portion recessed into the substrate 12. The side of the recessed portion facing away from the sidewall of the substrate 12 forms an inclined portion relative to the first surface. The angle between the inclined portion and the first surface is greater than or equal to 53° and less than or equal to 57°. During the etching process to form the first isolation region 6 and the second isolation region 9, the alkaline solution etches from the surface inwards. The etching principle is the anisotropic etching of silicon in an alkaline solution (similar to conventional alkaline texturing processes). The formed sidewall is actually one sidewall of a textured pyramid, thus forming the inclined portion. That is, along the substrate 12 from bottom to top, the inclined portions gradually tilt away from the sidewall of the substrate 12. The angle between the inclined portion of the first isolation region 6 and the first surface is α, and the angle between the inclined portion of the second isolation region 9 and the first surface is β. Angles α and β ensure a continuous and smooth transition of the subsequent passivation layer, i.e., a transition from the doped layer to the substrate of the isolation region, ensuring the electrical isolation and moisture barrier effects of the isolation region.

[0118] For example, the included angle α between the first inclined portion and the first surface can be 53°, 53.5°, 54°, 54.5°, 55°, 55.5°, 56°, 56.5°, or 57°. The included angle β between the second inclined portion and the first surface can be 53°, 53.5°, 54°, 54.5°, 55°, 55.5°, 56°, 56.5°, or 57°.

[0119] The first isolation region 6 and / or the second isolation region 9 have recessed portions that extend into the substrate. The bottom surface of these recessed portions forms a textured structure, which can be a ridge structure or a pyramidal texturing structure. As can be seen, during the etching process to form the first isolation region 6 and the second isolation region 9, the etching occurs from the surface inwards in the alkaline solution. The etching principle is the anisotropic etching of silicon under the etching solution (similar to conventional alkaline texturing processes). This results in the bottom walls of the first isolation region 6 and the second isolation region 9 having a pyramidal texturing structure, allowing them to better isolate the doped layer from the edge of the first surface. Furthermore, the textured bottom walls of the first isolation region 6 and the second isolation region 9 increase the path length for moisture to enter the solar cell, reducing moisture ingress and thus preventing moisture from affecting the performance of the doped layer.

[0120] In another specific embodiment, the length and / or width of the substrate 12 is 166μm-210μm. For example, the length of the substrate 12 can be 166μm, 170μm, 180μm, 190μm, 200μm, or 210μm. The width of the substrate 12 can be 166μm, 170μm, 180μm, 190μm, 200μm, or 210μm.

[0121] The thickness of the substrate 12 is 100μm-170μm. For example, the thickness of the substrate 12 can be 100μm, 110μm, 120μm, 130μm, 140μm, 150μm, 160μm or 170μm.

[0122] The thickness of the first doped layer 3 and / or the second doped layer 4 is 150 nm to 400 nm. Specifically, the thickness of the first doped layer 3 can be 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm, 380 nm, or 400 nm. The thickness of the second doped layer 4 can be 150 nm, 180 nm, 200 nm, 220 nm, 250 nm, 280 nm, 300 nm, 320 nm, 350 nm, 380 nm, or 400 nm. Thus, while ensuring good field passivation, the poly thickness is minimized to reduce parasitic absorption.

[0123] As one possible implementation, the back contact battery further includes a passivation layer 11 covering the first doped layer 3, the second doped layer 4, the first isolation region 6, and the second isolation region 9. The passivation layer 11 can improve the stability and reliability of the substrate 12, protect the surface of the substrate 12, and prevent oxidation, corrosion, contamination, etc., from occurring on the surface of the substrate 12. Furthermore, the passivation layer 11 covers the inner walls of the first isolation region 6 and the second isolation region 9, which can further prevent moisture from entering the battery cell from within the isolation regions, preventing moisture from affecting the performance of the doped layers.

[0124] Furthermore, this application also provides a photovoltaic module, which includes at least two back contact cells and a plurality of electrical connectors, wherein the back contact cells are the back contact cells provided in any of the above embodiments. The plurality of electrical connectors connect at least two back contact cells. Compared with the prior art, the beneficial effects of the photovoltaic module provided in this application are the same as those of the aforementioned back contact cells, and will not be elaborated further here.

[0125] Multiple back-contact batteries can be connected in series and / or in parallel via electrical connectors. These connectors can be solder strips, specifically tin-plated or tin-coated copper strips.

[0126] In the aforementioned photovoltaic module, the edges have a first edge 1 and a second edge 2 opposite to each other, and a third edge 5 located between the first edge and the second edge. The first edge 1 and the second edge 2 are parallel to each other and are located on opposite sides of the first surface, respectively, and the third edge 5 may be perpendicular to the first edge 1 and the second edge 2.

[0127] In one specific embodiment, the first doped layer 3 and the second doped layer 4 are arranged in an interdigitated pattern. The first doped layer 3 includes a first connecting portion and a plurality of first interdigitated portions, and at least one first interdigitated portion is electrically connected to the first connecting portion. The second doped layer 4 includes a second connecting portion and a plurality of second interdigitated portions, and at least one second interdigitated portion is electrically connected to the second connecting portion. The first connecting portion and the second connecting portion extend along the first edge and the second edge. The plurality of first interdigitated portions and the plurality of second interdigitated portions between the first connecting portion and the second connecting portion are arranged in multiple rows, and the multiple rows of first interdigitated portions and the multiple rows of second interdigitated portions are staggered.

[0128] In the above scheme, the first connecting part and the second connecting part can be respectively arranged adjacent to the first edge 1 and the second edge 2, and there are multiple rows of first interdigitated fingers and multiple rows of second interdigitated fingers between the first connecting part and the second connecting part, and the multiple rows of first interdigitated fingers and multiple rows of second interdigitated fingers between the first connecting part and the second connecting part are staggered.

[0129] In the above technical solution, the orthographic projections of multiple electrical connectors and the first connection portions of the first doped layer 3 adjacent to the first edge 1 and / or the second edge 2 on the back contact battery do not overlap, and the orthographic projections of multiple electrical connectors and the second connection portions of the second doped layer 4 adjacent to the first edge 1 and / or the second edge 2 on the back contact battery do not overlap. That is, the first connection portions adjacent to the first edge and / or the second edge 2 are staggered with the electrical connectors, and the second connection portions adjacent to the first edge and / or the second edge 2 are staggered with the electrical connectors. Thus, the electrical connectors being offset from the first and second connection portions adjacent to the first edge 1 and / or the second edge 2 prevent damage to these portions, ensuring the collection efficiency of the first and second connection portions adjacent to the first edge 1 and / or the second edge 2, while further improving electrical isolation.

[0130] For a back contact battery with a main grid, there are connecting portions (the first connecting portion of the first doped layer 3 and / or the second connecting portion of the second doped layer 4) near the first edge 1 and the second edge 2 and in the middle. At this time, the two electrical connectors adjacent to the first edge 1 and the second edge 2 do not overlap with the orthographic projection of the connecting portions adjacent to the first edge 1 and the second edge 2 on the back contact battery, and the electrical connector in the middle overlaps with the orthographic projection of the connecting portion in the middle on the back contact battery.

[0131] In the above embodiments, for a back contact battery without a main grid, a connection portion (the first connection portion of the first doped layer 3 and / or the second connection portion of the second doped layer 4) is provided only near the first edge 1 and the second edge 2. At this time, the two electrical connectors adjacent to the first edge 1 and the second edge 2 do not overlap with the orthographic projection of the connection portion adjacent to the first edge 1 and the second edge 2 on the back contact battery.

[0132] For another type of back-contact cell without a main grid, the first doped layer 3 includes a plurality of first strip-shaped portions extending along the direction of the third edge 5, and the second doped layer 4 includes a plurality of second strip-shaped portions extending along the direction of the third edge 5. The plurality of first strip-shaped portions and the plurality of second strip-shaped portions are alternately arranged along the extension direction of the first edge 1 or the second edge 2, and the two ends of the first strip-shaped portions and the second strip-shaped portions are respectively adjacent to the first edge 1 and the second edge 2. This implementation is a back-contact cell without a main grid, in which the doped layer does not have an interdigitated structure, but only includes strip-shaped portions. The ends of the strip-shaped portions form a first isolation region 6 or a second isolation region 9 between the corresponding edges to ensure the isolation effect of the first edge 1 and the second edge 2. Furthermore, the electrical connector is arranged perpendicularly to the strip-shaped portions, and the electrical connector is electrically connected to the strip-shaped portions at the intersection position through an electrode pattern.

[0133] This application also provides a method for preparing a back contact battery, including the following steps:

[0134] A substrate 12 is provided, the substrate 12 having opposing first and second surfaces, the substrate 12 having an edge, and the first surface having a first region and a second region, and a third region between the first doped layer and the second doped layer;

[0135] A first doped layer 3 is formed and patterned on the first surface of the substrate 12, wherein the doping type of the first doped layer 3 is opposite to that of the substrate 12.

[0136] A second doped layer 4 is formed and patterned on the first surface of the substrate 12, wherein the doping type of the second doped layer 4 is opposite to that of the first doped layer 3.

[0137] When patterning the first doped layer 3 or the second doped layer 4, a first isolation region 6 is formed that penetrates the first doped layer 3 along the thickness direction of the substrate 12, and the first isolation region 6 separates the first doped layer 3 from the edge; and a second isolation region 9 is formed that penetrates the second doped layer 4 along the thickness direction of the substrate 12, and the second isolation region 9 separates the second doped layer 4 from the edge, and the width of the first isolation region 6 is greater than the width of the second isolation region 9.

[0138] Compared with the prior art, the beneficial effects of the method for manufacturing the back contact battery provided in this application embodiment are the same as the beneficial effects of the back contact battery described above, and will not be repeated here.

[0139] The above-mentioned method for manufacturing a back-contact battery may further include the following steps:

[0140] A passivation layer 11 is formed covering the first doped layer 3, the second doped layer 4, the first isolation region 6, and the second isolation region 9;

[0141] A first electrode is formed that is connected to the first doped layer 3, and a second electrode is formed that is connected to the second doped layer 4.

[0142] In practical applications, the substrate 12 requires polishing and cleaning to remove damage. The processes for forming the first doped layer 3 on the substrate 12, and for forming the doped film on the first doped layer 3 and the first surface, can be plasma chemical vapor deposition (PECVD), hot-filament chemical vapor deposition, physical vapor deposition (PVD), low-pressure chemical vapor deposition (LPCVD), or catalytic chemical vapor deposition, etc. The processes for removing the first doped layer 3 located in the second doped layer and the third region, and for removing the doped film on the third region, can be laser etching, ion milling, plasma etching, reactive ion etching, alkaline etching, and acid etching, etc.

[0143] In some embodiments, the first doped layer 3 and the doped film are formed by in-situ doping or non-in-situ doping. That is, the first doped layer 3 and the doped film can be formed directly, or the intrinsic semiconductor layer and the intrinsic semiconductor film can be formed first, and then the first doped layer 3 and the doped film can be formed by doping respectively.

[0144] The step of forming the first isolation region 6 penetrating the first doped layer 3 along the thickness direction of the substrate 12 includes: firstly, irradiating a portion of the first doped layer 3 at the corresponding position of the first isolation region 6 with a laser, and then forming the first isolation region 6 penetrating the first doped layer 3 along the thickness direction of the substrate 12 by etching with an etchant. The step of forming the second isolation region 9 penetrating the second doped layer 4 along the thickness direction of the substrate 12 includes: forming the second isolation region 9 penetrating the second doped layer 4 along the thickness direction of the substrate 12 by etching with an etchant. Since the first isolation region 6 is wider, laser irradiation is used first, while the second isolation region 9 is narrower and is formed only by etching with an etchant, thereby ensuring that the width of the first isolation region 6 is greater than the width of the second isolation region 9.

[0145] In addition, forming a first isolation region 6 that penetrates the first doped layer 3 along the thickness direction of the substrate 12 includes: forming a portion of the first isolation region 6 that is recessed into the substrate 12, and forming a textured structure on the bottom surface of the recessed portion; the textured structure includes a pyramid-shaped velvet structure.

[0146] Forming a second isolation region 9 that penetrates the second doped layer 4 along the thickness direction of the substrate 12 includes: forming a recessed portion of the second isolation region 9 into the substrate 12, the bottom surface of which forms a textured structure; the textured structure includes a pyramid-shaped velvety structure. The bottom walls of the first isolation region and the second isolation region are textured, which can increase the path length of water vapor entering the solar cell, reduce the entry of water vapor, and thus prevent water vapor from affecting the performance of the doped layer.

[0147] In practical applications, the widths of the first and second electrodes range from 5 μm to 100 μm. The processes for forming the first and second electrodes can include electroplating, transfer printing (e.g., laser transfer, thermal transfer), screen printing, physical vapor deposition of metal or metal oxide electrodes, etc. Obviously, various processes can also be combined. For example, electrodes can be printed first to form power supply points, and then electricity can be applied to these points using electroplating to form the final first and second electrodes; or metal oxide vapor deposition, such as transparent conductive oxide (TCO), can be used, followed by screen printing or transfer printing to form the first and second electrodes, etc.

[0148] In practical applications, the process for forming the passivation layer 11 can be plasma chemical vapor deposition (PECVD), hot-wire chemical vapor deposition, physical vapor deposition (PVD), low-pressure chemical vapor deposition (LPCVD), or catalytic chemical vapor deposition, etc. When the back contact battery has a passivation layer 11 and the first electrode and the second electrode are continuous contact electrodes, the method for forming the first electrode and the second electrode can also be to coat the electrode paste onto the passivation layer 11, and then sinter it so that the electrode paste passes through the passivation layer 11 and forms electrical contact with the first doped layer 3 and the second doped layer 4, respectively. When the back contact battery has a passivation layer 11 and the first electrode and the second electrode are partial contact electrodes, the method for forming the first electrode and the second electrode can also be to first open the first opening and the second opening on the passivation layer 11, and then use methods such as printing paste, laser transfer, electroplating, chemical plating, photo-induced electroplating, or physical vapor deposition such as vacuum evaporation and magnetron sputtering to form the partial contact first electrode and the second electrode. The aperture method can include laser ablation or ablation using an etching paste that reacts with the passivation layer 11. Ablation for electrical contact allows for lower metal recombination in the back contact cell, ensuring high conversion efficiency. Obviously, one or more of the above methods can also be combined to form the first and second electrodes. For example, a physical vapor deposition (PVD) seed layer combined with printed electrodes, screen-printed electrode paste combined with electroplating, or a combination of laser transfer and screen printing sintering methods, etc.

[0149] The passivation layer 11 can be made of one or more of silicon nitride, silicon oxide, silicon oxynitride, aluminum oxide, silicon carbide, and amorphous silicon. For example, the passivation layer 11 can be made of silicon oxide.

[0150] The passivation layer 11 can passivate the back contact battery surface, passivate the dangling bonds in the first doped layer 3, the second doped layer 4 and the third region, reduce the carrier recombination rate on the first surface and improve the photoelectric conversion efficiency; at the same time, the passivation layer 11 located in the third region, the first isolation region 6 and the second isolation region 9 also serves to isolate the first doped layer 3 and the second doped layer 4.

[0151] As one possible implementation, after removing the doped film layer located on the third region, the step of texturing the third region is also included.

[0152] Preferably, the texturing process of the third region and the removal of the doped film layer located in the third region can be completed in the same step. For example, when removing the doped film layer located in the third region using alkaline etching, a textured structure can be formed on the third region simultaneously.

[0153] As some possible implementations, before forming the passivation layer 11 covering the first doped layer 3, the second doped layer 4, the first isolation region 6, and the second isolation region 9, the method further includes a heat treatment process that crystallizes at least a portion of the first doped layer 3 and / or the second doped layer 4. Heat treatment can be performed on p-type or n-type semiconductor layers to further distribute the dopant or to change the structure of the semiconductor layer, which is more conducive to improving battery performance. For example, when the first doped layer 3 and the second doped layer 4 are amorphous semiconductors or microcrystalline semiconductors, heat annealing can crystallize at least a portion of the first doped layer 3 and / or the second doped layer 4, improving the conductivity of the first doped layer 3 and the second doped layer 4. Furthermore, heat annealing can make the tunneling oxide layer more conducive to selective carrier transport; heating can also allow dopants to enter the tunneling oxide layer and the substrate 12, thereby reducing transport resistance. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in any suitable manner in one or more embodiments or examples.

[0154] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A back-contact battery, characterized in that, include: A substrate having opposing first and second surfaces; A first doped layer and a second doped layer are alternately disposed on the first surface. The doping types of the first doped layer and the second doped layer are opposite, and the doping type of the second doped layer is the same as that of the substrate. The substrate has an edge, and a first isolation region is formed between the boundary of the first doped layer adjacent to the edge and the edge, and a second isolation region is formed between the boundary of the second doped layer adjacent to the edge and the edge, wherein at least a portion of the width of the first isolation region is greater than at least a portion of the width of the second isolation region.

2. The back contact battery according to claim 1, characterized in that, The edge includes a first edge and a second edge that are disposed opposite to each other, wherein, The back contact battery is a whole battery. The first surface is divided into two partitions by a dividing line perpendicular to the first edge and the second edge. In one partition, the width of the first isolation region formed between the boundary of the first doped layer and the first edge is greater than the width of the second isolation region formed between the boundary of the second doped layer and the second edge. or, The back contact battery is a half-cell battery, and the width of the first isolation region formed between the boundary of the first doped layer and the first edge is greater than the width of the second isolation region formed between the boundary of the second doped layer and the second edge.

3. The back contact battery according to claim 1, characterized in that, The edge includes a first edge and a second edge disposed opposite to each other, and a third edge located between the first edge and the second edge, wherein, The first doped layer and the second doped layer are arranged in an interdigitated pattern. The first doped layer includes a first connecting portion and a plurality of first interdigitated portions, and at least one first interdigitated portion is electrically connected to the first connecting portion. The second doped layer includes a second connecting portion and a plurality of second interdigitated portions, and at least one second interdigitated portion is electrically connected to the second connecting portion. The first connecting portion and the second connecting portion extend along the first edge and the second edge. The plurality of first interdigitated portions and the plurality of second interdigitated portions between the first connecting portion and the second connecting portion are arranged in multiple rows, and the multiple rows of first interdigitated portions and the multiple rows of second interdigitated portions are staggered. The back contact battery is a half-cell battery, and the width of the first isolation area formed between the first connecting portion and the first edge is greater than the width of the second isolation area formed between the second connecting portion and the second edge; or... The back contact battery is a single battery, and in one of the partitions, the width of the first isolation zone formed between the first connecting part and the first edge is greater than the width of the second isolation zone formed between the second connecting part and the second edge.

4. The back contact battery according to claim 3, characterized in that, The first interdigitated fingers in any row between the first connecting portion and the second connecting portion are continuous and uninterrupted, and the second interdigitated fingers in any row between the first connecting portion and the second connecting portion are continuous and uninterrupted.

5. The back contact battery according to claim 3, characterized in that, The first interdigitated portion between the first connecting portion and the second connecting portion is intermittently formed into multiple segments, and the second interdigitated portion between the first connecting portion and the second connecting portion is intermittently formed into multiple segments.

6. The back contact battery according to claim 3, characterized in that, The third edge is adjacent to the boundary of the first interdigitated portion; or, the third edge is adjacent to the boundary of the second interdigitated portion.

7. The back contact battery according to claim 3, characterized in that, One end of the third edge is connected to the end of the first edge by a first chamfer; the other end of the third edge is connected to the end of the second edge by a second chamfer; the boundary of the first doped layer is adjacent to the first chamfer, and the boundary of the second doped layer is adjacent to the second chamfer; The boundary of the first doped layer adjacent to the first chamfer is a stepped edge; And / or, the boundary of the second doped layer adjacent to the second chamfer is an arc-shaped edge; and / or, the distance between the end of the second interdigitated portion near the first chamfer and the first connecting portion along the third edge direction is greater than the distance between the end of the remaining second interdigitated portions and the first connecting portion along the third edge direction; and / or, the distance between the end of the first interdigitated portion near the second chamfer and the second connecting portion along the third edge direction is greater than the distance between the end of the remaining first interdigitated portions and the second connecting portion along the third edge direction.

8. The back contact battery according to claim 3, characterized in that, One end of the third edge is connected to the end of the first edge by a first chamfer; the other end of the third edge is connected to the end of the second edge by a second chamfer. Wherein, the first interdigitated part is adjacent to the third edge, and the end edge of the first interdigitated part near the second connecting part is a bevel, and the bevel gradually slopes towards the second chamfer along the direction away from the third edge; or, the second interdigitated part is adjacent to the third edge, and the end edge of the second interdigitated part near the first connecting part is a bevel, and the bevel gradually slopes towards the first chamfer along the direction away from the third edge.

9. The back contact battery according to claim 3, characterized in that, The width of the portion of the first connecting part adjacent to the first edge is d1, and the width of the portion of the second connecting part adjacent to the second edge is d2, where d1 < d2.

10. The back contact battery according to claim 9, characterized in that, 600μm≤d1≤800μm, 800μm≤d2≤1100μm.

11. The back contact battery according to claim 1, characterized in that, The edge has a first edge and a second edge opposite to each other, and a third edge located between the first edge and the second edge; The first doped layer includes a plurality of first strips extending along the third edge direction, and the second doped layer includes a plurality of second strips extending along the third edge direction. The plurality of first strips and the plurality of second strips are alternately spaced along the extension direction of the first edge or the second edge, and the two ends of the first strips and the second strips are respectively adjacent to the first edge and the second edge.

12. The back contact battery according to claim 11, characterized in that, The boundary of the second strip is immediately adjacent to the third edge.

13. The back contact battery according to any one of claims 1-12, characterized in that, The width of the first isolation region is 80μm-200μm; and / or the width of the second isolation region is 10μm-50μm; and / or the difference between the width of the first isolation region and the width of the second isolation region is greater than or equal to 30μm and less than or equal to 190μm.

14. The back contact battery according to any one of claims 1-12, characterized in that, The first isolation region and / or the second isolation region have a portion recessed into the substrate, and the side of the recessed portion away from the sidewall of the substrate forms an inclined portion that is inclined relative to the first surface, the angle between the inclined portion and the first surface being greater than or equal to 53° and less than or equal to 57°.

15. The back contact battery according to any one of claims 1-12, characterized in that, The first isolation region and / or the second isolation region have a portion recessed into the substrate, and the bottom surface of the recessed portion forms a textured structure; the textured structure includes a pyramid-shaped velvet structure.

16. The back contact battery according to any one of claims 1-12, characterized in that, The substrate has a length and / or width of 166μm-210μm; and / or, the substrate has a thickness of 100μm-170μm; and / or, the first doped layer and / or the second doped layer has a thickness of 150nm-400nm; and / or, a third isolation region is provided between the first doped layer and the second doped layer, the width of the third isolation region being 60μm-200μm.

17. A photovoltaic module, characterized in that, It includes at least two back contact batteries as described in any one of claims 1-16 and a plurality of electrical connectors, wherein the plurality of electrical connectors connect the at least two back contact batteries.

18. The photovoltaic module according to claim 17, characterized in that, The edges include a first edge and a second edge disposed opposite to each other; the first doped layer and the second doped layer are arranged in a quasi-interdigital pattern, the first doped layer includes a first connecting portion and a plurality of first interdigital portions, at least one of the first interdigital portions being electrically connected to the first connecting portion; the second doped layer includes a second connecting portion and a plurality of second interdigital portions, at least one of the second interdigital portions being electrically connected to the second connecting portion; the first connecting portion and the second connecting portion extend along the first edge and the second edge, and the plurality of first interdigital portions and the plurality of second interdigital portions between the first connecting portion and the second connecting portion are arranged in multiple rows, with the multiple rows of first interdigital portions and the multiple rows of second interdigital portions being staggered and spaced apart; The back contact battery is a half-cell battery, with the first connecting portion adjacent to the first edge and the second connecting portion adjacent to the second edge; The projections of the plurality of electrical connectors onto the back contact battery do not overlap with the first connection portion of the first doped layer and / or the second connection portion of the second doped layer adjacent to the first edge and / or the second edge.

19. A method for preparing a back-contact battery, characterized in that, include: A substrate is provided, the substrate having opposing first and second surfaces, the first surface having an edge; A first doped layer is formed and patterned on a first surface of the substrate, wherein the doping type of the first doped layer is opposite to that of the substrate; A second doped layer is formed and patterned on the first surface of the substrate, wherein the doping type of the second doped layer is opposite to that of the first doped layer. When the first doped layer or the second doped layer is patterned, a first isolation region is formed that penetrates the first doped layer along the thickness direction of the substrate, and the first isolation region separates the first doped layer from the edge; A second isolation region is formed that extends through the second doped layer along the thickness direction of the substrate, the second isolation region separating the second doped layer from the edge, and the width of the first isolation region is greater than the width of the second isolation region.

20. The method for preparing a back contact battery according to claim 19, characterized in that, The step of forming a first isolation region penetrating the first doped layer along the thickness direction of the substrate includes: firstly, irradiating the first doped layer portion at the corresponding position of the first isolation region with a laser, and then forming the first isolation region penetrating the first doped layer along the thickness direction of the substrate by etching with an etchant. The step of forming a second isolation region penetrating the second doped layer along the thickness direction of the substrate includes: forming the second isolation region penetrating the second doped layer along the thickness direction of the substrate by etching with an etchant.

21. The method for preparing a back contact battery according to claim 20, characterized in that, Forming a first isolation region penetrating the first doped layer along the thickness direction of the substrate includes: forming a portion of the first isolation region recessed into the substrate, wherein the bottom surface of the recessed portion forms a textured structure; the textured structure includes a pyramidal velvet structure; Forming a second isolation region penetrating the second doped layer along the thickness direction of the substrate includes: forming a portion of the second isolation region recessed into the substrate, wherein the bottom surface of the recessed portion forms a textured structure; the textured structure includes a pyramidal velvet structure.

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