Back contact battery, battery assembly and photovoltaic system

Abstract

The invention relates to the technical field of solar cells, and particularly discloses a back contact cell, a cell assembly and a photovoltaic system, the back contact cell comprises a substrate, the back surface of the substrate is provided with a plurality of first areas and second areas which are alternately arranged along a first direction; the first semiconductor layer is arranged in the first region and comprises a first doped layer; the second semiconductor layer is at least partially arranged in the second region and comprises a second doped layer; the TCO layer comprises a first TCO section arranged in the first region and a second TCO section arranged in the second region, at least partial region of the first TCO section is electrically connected with the first doping layer, at least partial region of the second TCO section is electrically connected with the second doping layer, the first TCO section and the second TCO section are arranged in a spaced and staggered mode in the first direction, the first TCO section and / or the second TCO section comprise / comprises a main body, and the main body is arranged between the first TCO section and the second TCO section. A plurality of protruding parts extending in the direction away from the body are arranged on the side walls of the two ends of the body in the first direction. The area of the conductive regions can be effectively increased, and the contrast ratio of boundaries between different conductive regions is improved, so that the alignment precision of subsequent procedures can be improved, and the production yield and the photoelectric conversion efficiency of the back contact battery are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a back-contact cell, a cell assembly and a photovoltaic system. Background Art

[0002] Existing back-contact cells typically alternate between P-type emitters and N-type back surface fields on the backlit side of a silicon wafer. Because there are no metal electrodes blocking the light-receiving side of the silicon wafer, these cells offer high light utilization, high short-circuit current, and high open-circuit voltage, making them a promising technology for future high-efficiency crystalline silicon cells. In some back-contact cells, such as HBC and TBC, a transparent conductive film is sputtered over the P-type emitter and N-type back surface fields. Laser-assisted isolation trenches are then created to isolate the PN regions, and metal electrodes are then formed on the transparent conductive film.

[0003] However, currently manufactured back-contact cells typically utilize wide isolation trenches, which reduces the conductive area and hinders the improvement of the cell's photoelectric conversion efficiency. Furthermore, because the P-type emitter and N-type back surface field of back-contact cells are both located on the same side of the cell, the staggered arrangement of opposite-sex electrodes and the denser arrangement of electrodes require higher alignment precision during each process, resulting in poor cell production yields and hindering the improvement of cell conversion efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a back-contact battery, battery assembly and photovoltaic system in response to the existing technical status.

[0005] In the present invention, by providing raised portions on the side walls at both ends of the first TCO segment and / or the second TCO segment, the area of the conductive region is effectively increased, so that both electrons and holes can be promptly conducted out, thereby improving the photoelectric conversion efficiency of the back contact cell. At the same time, the provision of the raised portions causes the edges at both ends of the first TCO segment and / or the second TCO segment to form a concave and convex morphology, which can improve the contrast of the dividing lines between different conductive regions, thereby improving the alignment accuracy of subsequent processes such as screen printing electrodes, effectively reducing the production difficulty, and improving the production yield and photoelectric conversion efficiency of the back contact cell.

[0006] In order to achieve the above object, the present invention adopts the following technical scheme:

[0007] First, the present invention provides a back-contact battery, comprising:

[0008] A substrate, the substrate comprising a front surface and a back surface opposite to each other, the back surface having a plurality of first areas and second areas alternately arranged along a first direction;

[0009] A first semiconductor layer, provided in the first region, comprising a first doped layer;

[0010] A second semiconductor layer, at least partially disposed in the second region, includes a second doped layer, and the polarity of the second doped layer is opposite to that of the first doped layer;

[0011] A TCO layer includes a first TCO segment disposed in the first region and a second TCO segment disposed in the second region. At least a partial region of the first TCO segment is electrically connected to the first doped layer, and at least a partial region of the second TCO segment is electrically connected to the second doped layer. The first TCO segment and the second TCO segment are arranged in a spaced and staggered manner in the first direction, and the first TCO segment and / or the second TCO segment includes a main body, and a plurality of protrusions extending in a direction away from the main body are provided on both side walls at both ends of the main body in the first direction.

[0012] In some embodiments, the cross-section of the protrusion is a single-peak structure or a multi-peak structure. The multi-peak structure includes a plurality of single-peak structures that are at least partially connected. The single-peak structure is a spike-like structure or a hump-like structure.

[0013] In some embodiments, in the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0014] h = a × w G

[0015] wherein, w G is the width distance between the main body of the adjacent first TCO segment and the main body of the second TCO segment in the first direction, and a is 0.7% to 3.5%.

[0016] In some embodiments, in the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is 5 μm to 25 μm.

[0017] In some embodiments, the protrusion includes a first protrusion located on the first TCO segment. In the first direction, the relative distance h1 between the end of the first protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0018] h1 = b × w1

[0019] wherein, w1 is the width distance of the main body to which the first protrusion is connected in the first direction, and b is 1% to 6.25%.

[0020] In some embodiments, the protrusion includes a second protrusion located on the second TCO segment. In the first direction, the relative distance h2 between the end of the second protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0021] h2 = c × w2

[0022] In the formula, w1 is the width distance of the main body to which the second protrusion is connected in the first direction, and c is 1% to 6.25%.

[0023] In some embodiments, a protective ink layer is further included.

[0024] The protective ink layer includes a first ink portion and a second ink portion. At least a part of the first ink portion and at least a part of the second ink portion are disposed on a side of the first TCO segment facing away from the substrate. The first ink portion and the second ink portion are respectively disposed at two ends of the first TCO segment in the first direction. The first ink portion and the second ink portion form a serrated edge on a side away from each other in the first direction, and a plurality of first protrusion units disposed outside the edge of the first TCO segment are provided on both the first ink portion and the second ink portion; and / or

[0025] The protective ink layer includes a third ink portion and a fourth ink portion. At least a part of the third ink portion and at least a part of the fourth ink portion are disposed on a side of the second TCO segment facing away from the substrate. The third ink portion and the fourth ink portion are respectively disposed at two ends of the second TCO segment in the first direction. The third ink portion and the fourth ink portion form a serrated edge on a side away from each other in the first direction, and a plurality of second protrusion units disposed outside the edge of the second TCO segment are provided on both the third ink portion and the fourth ink portion.

[0026] In some embodiments, the second semiconductor layer includes a first segment disposed in the first region and a second segment disposed in the second region. The first segment is connected to the second segment. The first segment is disposed on a side of the first semiconductor layer facing away from the substrate, and an insulating protective layer is provided between the first segment and the first semiconductor layer. An avoidance hole is provided in the first region, and the avoidance hole penetrates through a part of the first segment and a part of the insulating protective layer. At least a part of the first TCO segment is disposed in the avoidance hole and is in contact with a side of the first doped layer facing away from the substrate.

[0027] In some embodiments, the first TCO segment includes a first extension segment and a second extension segment connected to each other. The first extension segment is disposed in the avoidance hole and is in contact with the first doping layer. The second extension segment is disposed on a side of the second doping layer facing away from the substrate. In the thickness direction of the substrate, the relative distance between the second extension segment and the front surface is greater than or less than the relative distance between the second TCO segment and the front surface. The second segment is provided with a parallel segment and a connection segment connected to each other. The parallel segment is parallel to and in contact with the second TCO segment. The connection segment is connected to the first segment, and at least a partial region of the connection segment is not covered by the TCO layer.

[0028] In some embodiments, the first semiconductor layer further includes a first passivation layer disposed between the first doping layer and the back surface; and / or,

[0029] The second semiconductor layer further includes a second passivation layer disposed on a side of the second doping layer facing the back surface.

[0030] Secondly, the present invention provides a battery assembly including the above-mentioned back-contact battery.

[0031] Furthermore, the present invention provides a photovoltaic system including the above-mentioned battery assembly.

[0032] The beneficial effects of the present invention are as follows:

[0033] In the present invention, by providing a first TCO segment electrically connected to the first doping layer and a second TCO segment electrically connected to the second doping layer, the two are arranged at intervals and staggered in a first direction, and a plurality of protrusions extending in a direction away from their main bodies are provided on side walls at both ends of the first TCO segment and / or the second TCO segment. On the premise of suppressing leakage, by providing protrusions on side walls at both ends of the first TCO segment and / or the second TCO segment, the conductive area is effectively increased, so that both electrons and holes can be timely exported, improving the photoelectric conversion efficiency of the back-contact battery. At the same time, the provision of the protrusions makes the two ends of the first TCO segment and / or the second TCO segment form an uneven topography, which can improve the contrast of the boundary line between different conductive regions, thereby improving the alignment accuracy of subsequent processes such as screen-printed electrodes, reducing the difficulty of precise alignment, effectively reducing the production difficulty, and improving the production yield and photoelectric conversion efficiency of the back-contact battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic structural diagram of a back-contact battery of the present invention.

[0035] Figure 2 is a schematic structural diagram of the TCO layer of the present invention.

[0036] Figure 3 Schematic diagram of the structure of the first TCO segment of the present invention.

[0037] Figure 4 Schematic diagram of the structure of the second TCO segment of the present invention.

[0038] Figure 5 Partial SEM image of the edge of the protective ink layer of the present invention (the dark part in the figure is the protective ink layer).

[0039] Figure 6 Partial SEM image of the protective ink layer on the TCO layer of the present invention.

[0040] In the figure:

[0041] Substrate 1;

[0042] First semiconductor layer 2, first doping layer 21, first passivation layer 22;

[0043] Second semiconductor layer 3, first segment 3A, second segment 3B, parallel segment 3B1, connecting segment 3B2, second doping layer 31, second passivation layer 32;

[0044] TCO layer 4, first TCO segment 41, first extension segment 411, second extension segment 412, second TCO segment 42, main body 43, first main body 431, second main body 432, protrusion 44, first protrusion 441, second protrusion 442;

[0045] Protective ink layer 5, first ink portion 51, second ink portion 52, third ink portion 53, fourth ink portion 54, first protrusion unit 55, second protrusion unit 56;

[0046] Insulating protective layer 6;

[0047] Avoidance hole 7. Detailed implementation manners

[0048] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, where the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the accompanying drawings are exemplary and are only used to explain the present invention and should not be construed as limiting the present invention. In addition, it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0049] In the description of the present invention, the terms "first", "second", "third", "fourth", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", "third", "fourth", etc. may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meanings of "a plurality" and "several" are two or more, unless otherwise specifically defined.

[0050] In the description of the present invention, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the first feature and the second feature being in direct contact, or may include the first feature and the second feature not being in direct contact but being in contact through additional features therebetween.

[0051] First, refer to Figures 1 to 4 As shown, the present invention provides a back-contact battery, comprising:

[0052] A substrate 1, the substrate 1 comprising a front surface and a back surface which are oppositely arranged, and the back surface having a plurality of first regions and second regions which are alternately arranged along a first direction;

[0053] A first semiconductor layer 2, disposed in the first region, comprising a first doped layer 21;

[0054] A second semiconductor layer 3, at least partially disposed in the second region, comprising a second doped layer 31, and the polarity of the second doped layer 31 being opposite to the polarity of the first doped layer 21;

[0055] A TCO layer 4, comprising a first TCO segment 41 disposed in the first region and a second TCO segment 42 disposed in the second region, at least a partial region of the first TCO segment 41 being electrically connected to the first doped layer 21, at least a partial region of the second TCO segment 42 being electrically connected to the second doped layer 31, the first TCO segment 41 and the second TCO segment 42 being arranged in an alternating and spaced manner in the first direction, and the first TCO segment 41 and / or the second TCO segment 42 each comprising a main body 43, and a plurality of protruding portions 44 being provided on the side walls at both ends of the main body 43 in the first direction and extending in a direction away from the main body 43.

[0056] Among them, the substrate 1 has a front side and a back side that are oppositely arranged. Generally, the front side refers to the side where the light-receiving surface of the battery is located, that is, the side of the battery that receives light. A second passivation layer 32, an antireflection layer, etc. that are common in the art may also be provided on its surface, but are not limited thereto. Generally, the back side refers to the side where the light-backing surface of the battery is located, that is, the side of the battery that faces away from the sun. It should be noted that in some embodiments, the back side can also absorb the light incident through the back side and then generate a photocurrent. In some embodiments, the front side and the back side may have certain morphological changes. For example, the front side can be a textured surface structure, and the back side can be set as a textured surface structure in a certain area and a planar structure in a certain area. Exemplarily, the substrate 1 can be an N-type silicon substrate or a P-type silicon substrate, but is not limited thereto.

[0057] In the first embodiment, the first TCO segment 41 includes a main body 43 (the first main body 431), and a plurality of protrusions 44 (the first protrusions 441) extending in a direction away from the main body 43 are provided on the side walls at both ends of the main body 43 in the first direction.

[0058] In the second embodiment, the second TCO segment 42 includes a main body 43 (the second main body 432), and a plurality of protrusions 44 (the second protrusions 442) extending in a direction away from the main body 43 are provided on the side walls at both ends of the main body 43 in the first direction.

[0059] Preferably, in the third embodiment, the first TCO segment 41 includes a main body 43 (the first main body 431), and a plurality of protrusions 44 (the first protrusions 441) extending in a direction away from the main body 43 are provided on the side walls at both ends of the main body 43 in the first direction. The second TCO segment 42 includes a main body 43 (the second main body 432), and a plurality of protrusions 44 (the second protrusions 442) extending in a direction away from the main body 43 are provided on the side walls at both ends of the main body in the first direction.

[0060] It can be understood that in the following description, if not specifically specified, the descriptions of the main body 43 and the protrusions 44 can be applied to the main body 43 and the protrusions 44 of the first TCO segment 41, and can also be applied to the main body 43 and the protrusions 44 of the second TCO segment 42, and will not be repeated below.

[0061] It can be understood that the first TCO segment 41 and the second TCO segment 42 are arranged in an alternating and spaced manner in the first direction, which means that there is a discontinuity between adjacent first TCO segments 41 and second TCO segments 42, and the two are separated from each other.

[0062] In terms of the conduction type, the polarity of the first doping layer 21 and the polarity of the second doping layer 31 may be the same as that of the substrate 1 or opposite to that of the substrate 1, and it is only necessary to ensure that the polarity of the first doping layer 21 is opposite to that of the second doping layer 31. In terms of the arrangement of substances, the crystal phases of the first doping layer 21 and the second doping layer 31 may be amorphous, microcrystalline, nanocrystalline, single crystal, polycrystalline, etc.

[0063] In the prior art, both ends of the transparent conductive layer corresponding to the P-type region and the transparent conductive layer corresponding to the N-type region have regular planar structures. In the present invention, by providing a first TCO segment 41 electrically connected to the first doping layer 21 and a second TCO segment 42 electrically connected to the second doping layer 31, the two are arranged at intervals and staggered in a first direction, and a plurality of protrusions 44 extending in a direction away from its main body 43 are provided on both side walls at both ends of the first TCO segment 41 and / or the second TCO segment 42. On the premise of suppressing leakage, by providing the protrusions 44 on both side walls at both ends of the first TCO segment 41 and / or the second TCO segment 42, the conductive area is effectively increased, so that both electrons and holes can be timely exported, improving the photoelectric conversion efficiency of the back contact battery. At the same time, the setting of the protrusions 44 makes the two ends of the first TCO segment 41 and / or the second TCO segment 42 form an uneven topography, which can improve the contrast of the boundary line between different conductive regions, thereby improving the alignment accuracy of subsequent processes such as screen printing electrodes, reducing the difficulty of precise alignment, effectively reducing the production difficulty, and improving the production yield and photoelectric conversion efficiency of the back contact battery.

[0064] It can be understood that the first TCO segment 41 and the first doping layer 21 can be electrically connected through direct contact or indirectly through a conductive material layer. The contact can be that a partial area of the first TCO segment 41 contacts the first doping layer 21, or the entire area of the first TCO segment 41 contacts the first doping layer 21. Similarly, the second TCO segment 42 and the second doping layer 31 can be electrically connected through direct contact or indirectly through a conductive material layer. The contact can be that a partial area of the second TCO segment 42 contacts the second doping layer 31, or the entire area of the second TCO segment 42 contacts the second doping layer 31.

[0065] In some embodiments, the material of the first TCO segment and / or the second TCO segment can be any one of ITO, IWO, and AZO.

[0066] In some embodiments, the first TCO segment and / or the second TCO segment can be a single-layer material layer or a composite TCO material layer formed by stacking multiple material layers.

[0067] In some embodiments, the cross-section of the protrusion 44 has a single-peak structure or a multi-peak structure. The multi-peak structure includes several single-peak structures that are at least partially connected. The single-peak structure is a sharp-peak structure or a hump-shaped structure. Among them, the sharp-peak structure refers to a mountain-shaped structure with a sharp angle, and its contour is triangular or approximately triangular. The hump-shaped structure refers to a mountain-shaped structure in which the end far from the main body 43 is in an arc-shaped curve rather than a sharp angle. It can be understood that on the same side wall of the same main body 43, there can be both the protrusion 44 with a peak structure and the protrusion 44 with a multi-peak structure at the same time.

[0068] In some embodiments, referring to Figure 2 as shown, in the first direction, the relative distance h between the end of the protrusion 44 far from the main body 43 to which it is connected and the main body 43 to which it is connected is:

[0069] h = a × w G

[0070] wherein, w G is the width distance between the main body 43 of the adjacent first TCO segment 41 and the main body 43 of the second TCO segment 42 in the first direction, and a is 0.7% to 3.5%.

[0071] When the protrusion amplitude of the protrusion 44 is too small, the formed uneven topography is not obvious, and the increase in the area of the conductive region and the improvement of the contrast of the boundary line between different conductive regions are limited, which affects the alignment accuracy. When the protrusion amplitude of the protrusion 44 is too large, the risk of short circuit between different conductive regions in contact is likely to increase.

[0072] In some embodiments, in the first direction, the relative distance h between the end of the protrusion 44 far from the main body 43 to which it is connected and the main body 43 to which it is connected is 5 μm to 25 μm.

[0073] Exemplarily, h is 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 24 μm or 25 μm, but not limited thereto.

[0074] Currently, there are certain ranges of differences in the width dimensions and interval dimensions of the back contact battery on different conductive regions of the transparent conductive layer in the market. When h is 5 μm to 25 μm, it can adapt to different specifications of the back contact battery, can effectively separate adjacent different conductive regions while increasing the area of the conductive region, and form a distinct uneven topography, improve the alignment accuracy, reduce the difficulty of precise alignment, and thus effectively improve the production yield and photoelectric conversion efficiency of the battery.

[0075] In some embodiments, referring to Figures 1 to 3As shown, the convex portion 44 includes a first convex 441 located on the first TCO segment 41. In the first direction, the relative distance h1 between one end of the first convex 441 away from the main body 43 it is connected to and the main body 43 it is connected to is:

[0076] h1 = b × w1

[0077] In the formula, w1 is the width distance of the main body 43 to which the first convex 441 is connected in the first direction, and b is 1% to 6.25%.

[0078] In some embodiments, referring to Figure 2 and Figure 4 As shown, the convex portion 44 includes a second convex 442 located on the second TCO segment 42. In the first direction, the relative distance h2 between one end of the second convex 442 away from the main body 43 it is connected to and the main body 43 it is connected to is:

[0079] h2 = c × w2

[0080] In the formula, w1 is the width distance of the main body 43 to which the second convex 442 is connected in the first direction, and c is 1% to 6.25%.

[0081] In some embodiments, referring to Figure 1 , Figure 5 and Figure 6 As shown, it further includes a protective ink layer 5. The protective ink layer 5 includes a first ink portion 51 and a second ink portion 52. At least part of the first ink portion 51 and at least part of the second ink portion 52 are provided on the side of the first TCO segment 41 facing away from the substrate 1, and the first ink portion 51 and the second ink portion 52 are respectively provided at both ends of the first TCO segment 41 in the first direction. The sides of the first ink portion 51 and the second ink portion 52 that are away from each other in the first direction form a serrated edge, and a number of first protrusion units 55 are provided on both the first ink portion 51 and the second ink portion 52 outside the edge of the first TCO segment 41.

[0082] That is to say, partial regions of the first ink portion 51 and the second ink portion 52 are located on the first TCO segment 41, and there are first protrusion units 55 provided outside the edge of the first TCO segment 41 in the partial regions. Compared with the solution of only providing the convex portion 44 on the TCO layer 4, adopting the convex portion 44 provided on the TCO layer 4 in combination with the protective ink layer 5 with the first protrusion units 55 can further improve the contrast of the boundary line between different conductive regions. Cooperating with the concave-convex undulating morphology formed by the convex portion 44 of the first TCO segment 41, it can effectively improve the alignment accuracy of subsequent processes and reduce the alignment difficulty.

[0083] Among them, the protective ink layer 5 can be formed in the process of forming the isolation region that isolates the first TCO segment 41 from the second TCO segment 42. Exemplarily, ink is printed on the TCO layer 4, and then the TCO layer 4 in the area not covered by the ink is removed through a wet chemical process. Subsequently, the ink is cleaned, and during the cleaning process, local ink is retained to form the above-mentioned protective ink layer 5.

[0084] In some embodiments, referring to Figure 1 、 Figure 5 and Figure 6 as shown, it further includes a protective ink layer 5. The protective ink layer 5 includes a third ink portion 53 and a fourth ink portion 54. At least a part of the third ink portion 53 and at least a part of the fourth ink portion 54 are disposed on the side of the second TCO segment 42 facing away from the substrate 1, and the third ink portion 53 and the fourth ink portion 54 are respectively disposed at two ends of the second TCO segment 42 in the first direction. The third ink portion 53 and the fourth ink portion 54 form a serrated edge on the side away from each other in the first direction, and a plurality of second protrusion units 56 disposed outside the edge of the second TCO segment 42 are provided on both the third ink portion 53 and the fourth ink portion 54.

[0085] That is to say, local areas of the third ink portion 53 and the fourth ink portion 54 are located on the second TCO segment 42, and there are second protrusion units 56 disposed outside the edge of the second TCO segment 42. The second protrusion units 56 can cooperate with the edge of the second TCO segment 42 to jointly form an edge morphology with higher contrast, further improving the contrast of the boundary line between different conductive regions.

[0086] It can be understood that the protective ink layer 5 can be composed of a first ink portion 51 and a second ink portion 52, or can be composed of a third ink portion 53 and a fourth ink portion 54, or can be composed of the first ink portion 51, the second ink portion 52, the third ink portion 53 and the fourth ink portion 54.

[0087] In some embodiments, the second semiconductor layer 3 is completely disposed in the second region.

[0088] In some embodiments, referring to Figure 1 as shown, the second semiconductor layer 3 includes a first segment 3A disposed in the first region and a second segment 3B disposed in the second region. The first segment 3A is connected to the second segment 3B. The first segment 3A is disposed on the side of the first semiconductor layer 2 facing away from the substrate 1, and an insulating protective layer 6 is provided between the first segment 3A and the first semiconductor layer 2. An avoidance hole 7 is provided in the first region. The avoidance hole 7 penetrates through part of the first segment 3A and part of the insulating protective layer 6. At least a part of the first TCO segment 41 is disposed in the avoidance hole 7 and is in contact with the side of the first doping layer 21 facing away from the substrate 1.

[0089] The insulating protective layer 6 plays an isolation and protection role, and the material of the insulating protective layer 6 can be any one of PSG (phosphosilicate glass) and SiN x (silicon nitride).

[0090] On the one hand, the insulating protective layer 6 can electrically isolate the first doped layer 21 and the second doped layer 31. On the other hand, during the preparation process, laser grooving can be performed first to remove a part of the first segment 3A at the position corresponding to the avoidance hole 7, so that the insulating protective layer 6 is exposed. Then, a wet chemical process is used to remove a part of the insulating protective layer 6 at the position corresponding to the avoidance hole 7, so that the first doped layer 21 is exposed. Then, the TCO layer 4 is deposited. In this way, high-energy laser can be avoided from directly acting on the first doped layer 21 during the preparation process, effectively avoiding the short-circuit risk of the PN region inside the battery.

[0091] The second semiconductor layer 3 retains the first segment 3A in the first region and is stacked on the insulating protective layer. Compared with the part of the second semiconductor layer 3 in the first region completely, this stacking method can simplify the process and improve production efficiency.

[0092] In some embodiments, as shown in Figure 1 , the first TCO segment 41 includes a first extension segment 411 and a second extension segment 412 connected to each other. The first extension segment 411 is disposed in the avoidance hole 7 and is in contact with the first doped layer 21. The second extension segment 412 is disposed on the side of the second doped layer 31 facing away from the substrate 1. In the thickness direction of the substrate 1, the relative distance between the second extension segment 412 and the front surface is greater than or less than the relative distance between the second TCO segment 42 and the front surface. The second segment 3B is provided with a parallel segment 3B1 and a connecting segment 3B2 connected to each other. The parallel segment 3B1 is parallel to and in contact with the second TCO segment 42. The connecting segment 3B2 is connected to the first segment 3A. At least a part of the connecting segment 3B2 is not covered by the TCO layer 4 to form an isolation region.

[0093] Exemplarily, in some embodiments, as shown in Figure 1 , when there is a part of the second semiconductor layer 3 stacked on the first semiconductor layer 2, at this time, the relative distance between the second extension segment 412 and the front surface is greater than the relative distance between the second TCO segment 42 and the front surface. In some embodiments, when there is no part of the second semiconductor layer 3 stacked on the first semiconductor layer 2 and the first semiconductor layer 2 and the second semiconductor layer 3 are staggered in the first direction, at this time, the relative distance between the second extension segment 412 and the front surface is greater than or less than the relative distance between the second TCO segment 42 and the front surface.

[0094] Due to the height difference between the second extension segment 412 and the second TCO segment 42, which are staggered in the thickness direction, and the isolation region (i.e., the region of the connection segment 3B2 not covered by the TCO layer 4) is provided on the connection segment 3B2, this structure can reduce the interval size between the projections of the first TCO segment 41 and the second TCO segment 42 on the substrate while ensuring that the two can be isolated from each other, further increasing the area of the conductive region and facilitating the improvement of the battery conversion efficiency.

[0095] In some embodiments, referring to Figure 1 as shown, the first semiconductor layer 2 further includes a first passivation layer 22, and the first passivation layer 22 is disposed between the first doped layer 21 and the back surface.

[0096] By providing the first passivation layer 22, the passivation effect and the carrier transport effect are improved, which is conducive to enhancing the conversion efficiency of the battery.

[0097] In some embodiments, the first passivation layer 22 may be amorphous silicon or microcrystalline silicon, and the material of the first doped layer 21 may be doped amorphous silicon or doped microcrystalline silicon.

[0098] In some embodiments, preferably, the first passivation layer 22 may be a tunneling oxide layer, such as silicon oxide, titanium oxide, etc., and the material of the first doped layer 21 may be doped polysilicon.

[0099] In some embodiments, referring to Figure 1 as shown, the second semiconductor layer 3 further includes a second passivation layer 32, and the second passivation layer 32 is disposed on the side of the second doped layer 31 facing the back surface.

[0100] In some embodiments, the second passivation layer 32 may be a tunneling oxide layer, such as silicon oxide, titanium oxide, etc., and the material of the second doped layer 31 may be doped polysilicon.

[0101] In some embodiments, preferably, the second passivation layer 32 may be amorphous silicon or microcrystalline silicon, and the material of the second doped layer 31 may be doped amorphous silicon or doped microcrystalline silicon.

[0102] Secondly, the present invention provides a battery module, including the above-mentioned back-contact battery.

[0103] Furthermore, the present invention provides a photovoltaic system, including the above-mentioned battery module.

[0104] Among them, multiple battery modules can be connected in series or in parallel through a junction box to form a photovoltaic system. This photovoltaic system can be used in photovoltaic power stations, such as ground power stations, rooftop power stations, water surface power stations, etc., and can also be applied to devices or apparatuses that use solar energy for power generation, such as user solar power supplies, solar street lights, solar cars, solar buildings, etc., but not limited thereto.

[0105] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0106] Embodiment 1

[0107] First, this embodiment discloses a back-contact battery, including:

[0108] A substrate, the substrate includes a front surface and a back surface which are oppositely arranged, and the back surface has a plurality of first regions and second regions alternately arranged along a first direction;

[0109] A first semiconductor layer, disposed in the first region, including a first doped layer;

[0110] A second semiconductor layer, at least partially disposed in the second region, including a second doped layer, and the polarity of the second doped layer is opposite to that of the first doped layer;

[0111] A TCO layer, including a first TCO segment disposed in the first region and a second TCO segment disposed in the second region, at least a part of the first TCO segment is electrically connected to the first doped layer, at least a part of the second TCO segment is electrically connected to the second doped layer, the first TCO segment and the second TCO segment are arranged at intervals and staggered in the first direction, and the first TCO segment and the second TCO segment include a main body, and a plurality of convex portions extending along a direction away from the main body are provided on the side walls at both ends of the main body in the first direction.

[0112] In this embodiment, the cross section of the convex portion has a single-peak structure or a multi-peak structure, and the multi-peak structure includes a plurality of single-peak structures that are at least partially connected, and the single-peak structure is a peak-like structure or a hump-like structure.

[0113] In this embodiment, in the first direction, the relative distance h between the end of the convex portion far from the main body to which it is connected and the main body to which it is connected is:

[0114] h = a × w G

[0115] wherein, w G is the width distance between the main body of the adjacent first TCO segment and the main body of the second TCO segment in the first direction, and a is 0.70%.

[0116] In this embodiment, in the first direction, the relative distance h between the end of the convex portion far from the main body to which it is connected and the main body to which it is connected is 5 μm.

[0117] In this embodiment, the convex portion includes a first convex on the first TCO segment. In the first direction, the relative distance h1 between the end of the first convex far from the main body to which it is connected and the main body to which it is connected is:

[0118] h1 = b × w1

[0119] Wherein, w1 is the width distance of the main body connected by the first protrusion in the first direction, and b is 1.25%.

[0120] In this embodiment, the protrusion portion includes a second protrusion located on the second TCO segment. In the first direction, the relative distance h2 between one end of the second protrusion away from the main body it connects and the main body it connects is:

[0121] h2 = c × w2

[0122] Wherein, w1 is the width distance of the main body connected by the second protrusion in the first direction, and c is 1.25%.

[0123] In this embodiment, it further includes a protective ink layer. The protective ink layer includes a first ink portion and a second ink portion. At least part of the first ink portion and at least part of the second ink portion are arranged on the side of the first TCO segment facing away from the substrate, and the first ink portion and the second ink portion are respectively arranged at both ends of the first TCO segment in the first direction. The sides of the first ink portion and the second ink portion facing away from each other in the first direction form a serrated edge, and a number of first protrusion units are arranged outside the edge of the first TCO segment in both the first ink portion and the second ink portion.

[0124] In this embodiment, it further includes a protective ink layer. The protective ink layer includes a third ink portion and a fourth ink portion. At least part of the third ink portion and at least part of the fourth ink portion are arranged on the side of the second TCO segment facing away from the substrate, and the third ink portion and the fourth ink portion are respectively arranged at both ends of the second TCO segment in the first direction. The sides of the third ink portion and the fourth ink portion facing away from each other in the first direction form a serrated edge, and a number of second protrusion units are arranged outside the edge of the second TCO segment in both the third ink portion and the fourth ink portion.

[0125] In this embodiment, the second semiconductor layer is completely arranged in the second region.

[0126] In this embodiment, the second semiconductor layer includes a first segment arranged in the first region and a second segment arranged in the second region. The first segment is connected to the second segment. The first segment is arranged on the side of the first semiconductor layer facing away from the substrate, and an insulating protective layer is provided between the first segment and the first semiconductor layer. An avoidance hole is provided in the first region, and the avoidance hole penetrates through part of the first segment and part of the insulating protective layer. At least part of the first TCO segment is arranged in the avoidance hole and is in contact with the side of the first doping layer facing away from the substrate.

[0127] The insulating protective layer plays a role of isolation and protection, and the material of the insulating protective layer is PSG.

[0128] In this embodiment, the first TCO segment includes a first extension segment and a second extension segment that are connected to each other. The first extension segment is disposed in the avoidance hole and is in contact with the first doped layer. The second extension segment is disposed on the side of the second doped layer facing away from the substrate. In the thickness direction of the substrate, the relative distance between the second extension segment and the front surface is greater than the relative distance between the second TCO segment and the front surface. The second segment is provided with a parallel segment and a connection segment that are connected to each other. The parallel segment is parallel to and in contact with the second TCO segment. The connection segment is connected to the first segment, and at least part of the connection segment is not covered by the TCO layer.

[0129] In this embodiment, the first semiconductor layer further includes a first passivation layer, and the first passivation layer is disposed between the first doped layer and the back surface.

[0130] Among them, the material of the substrate is N-type single crystal silicon, the material of the first doped layer is N-type doped polycrystalline silicon, and the material of the first passivation layer is silicon oxide.

[0131] In this embodiment, the second semiconductor layer further includes a second passivation layer, and the second passivation layer is disposed on the side of the second doped layer facing the back surface.

[0132] In this embodiment, the second passivation layer is an a-Si:H(i) layer, and the material of the second doped layer is an a-Si:H(p) layer.

[0133] Secondly, this embodiment provides a battery module, including the above-mentioned back contact battery.

[0134] Furthermore, this embodiment provides a photovoltaic system, including the above-mentioned battery module.

[0135] Embodiment 2

[0136] First of all, this embodiment discloses a back contact battery, including:

[0137] A substrate, the substrate includes a front surface and a back surface that are oppositely arranged, and the back surface has a plurality of first regions and second regions that are alternately arranged along a first direction;

[0138] A first semiconductor layer, disposed in the first region, including a first doped layer;

[0139] A second semiconductor layer, at least partially disposed in the second region, including a second doped layer, and the polarity of the second doped layer is opposite to the polarity of the first doped layer;

[0140] The TCO layer includes a first TCO segment disposed in the first region and a second TCO segment disposed in the second region. At least a part of the first TCO segment is electrically connected to the first doping layer, and at least a part of the second TCO segment is electrically connected to the second doping layer. The first TCO segment and the second TCO segment are arranged at intervals and staggered in the first direction, and the first TCO segment and the second TCO segment include a main body, and a plurality of protrusions extending in a direction away from the main body are provided on the side walls at both ends of the main body in the first direction.

[0141] In this embodiment, the cross-section of the protrusion is a single-peak structure or a multi-peak structure. The multi-peak structure includes a plurality of single-peak structures that are at least partially connected. The single-peak structure is a sharp-peak structure or a hump-shaped structure.

[0142] In this embodiment, in the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0143] h = a × w G

[0144] In the formula, w G is the width distance between the main body of the adjacent first TCO segment and the main body of the second TCO segment in the first direction, and a is 3.5%.

[0145] In this embodiment, in the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is 25 μm.

[0146] In this embodiment, the protrusion includes a first protrusion located on the first TCO segment. In the first direction, the relative distance h1 between the end of the first protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0147] h1 = b × w1

[0148] In the formula, w1 is the width distance of the main body to which the first protrusion is connected in the first direction, and b is 6.25%.

[0149] In this embodiment, the protrusion includes a second protrusion located on the second TCO segment. In the first direction, the relative distance h2 between the end of the second protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0150] h2 = c × w2

[0151] In the formula, w1 is the width distance of the main body to which the second protrusion is connected in the first direction, and c is 6.25%.

[0152] In this embodiment, a protective ink layer is further included. The protective ink layer includes a first ink portion and a second ink portion. At least a part of the first ink portion and at least a part of the second ink portion are disposed on the side of the first TCO segment facing away from the substrate, and the first ink portion and the second ink portion are respectively disposed at two ends of the first TCO segment in the first direction. The sides of the first ink portion and the second ink portion facing away from each other in the first direction form a serrated edge, and a plurality of first protrusion units are provided on both the first ink portion and the second ink portion outside the edge of the first TCO segment.

[0153] In this embodiment, a protective ink layer is further included. The protective ink layer includes a third ink portion and a fourth ink portion. At least a part of the third ink portion and at least a part of the fourth ink portion are disposed on the side of the second TCO segment facing away from the substrate, and the third ink portion and the fourth ink portion are respectively disposed at two ends of the second TCO segment in the first direction. The sides of the third ink portion and the fourth ink portion facing away from each other in the first direction form a serrated edge, and a plurality of second protrusion units are provided on both the third ink portion and the fourth ink portion outside the edge of the second TCO segment.

[0154] In this embodiment, the second semiconductor layer is completely disposed in the second region.

[0155] In this embodiment, the second semiconductor layer includes a first segment disposed in the first region and a second segment disposed in the second region. The first segment is connected to the second segment. The first segment is disposed on the side of the first semiconductor layer facing away from the substrate, and an insulating protective layer is provided between the first segment and the first semiconductor layer. An avoidance hole is provided in the first region, and the avoidance hole penetrates through a part of the first segment and a part of the insulating protective layer. At least a part of the first TCO segment is disposed in the avoidance hole and is in contact with the side of the first doping layer facing away from the substrate.

[0156] The insulating protective layer plays a role of isolation and protection, and the material of the insulating protective layer is PSG.

[0157] In this embodiment, the first TCO segment includes a first extension segment and a second extension segment connected to each other. The first extension segment is disposed in the avoidance hole and is in contact with the first doping layer. The second extension segment is disposed on the side of the second doping layer facing away from the substrate. In the thickness direction of the substrate, the relative distance between the second extension segment and the front surface is greater than the relative distance between the second TCO segment and the front surface. The second segment includes a parallel segment and a connection segment connected to each other. The parallel segment is parallel to and in contact with the second TCO segment, and the connection segment is connected to the first segment. At least a part of the connection segment is not covered by the TCO layer.

[0158] In this embodiment, the first semiconductor layer further includes a first passivation layer, and the first passivation layer is disposed between the first doping layer and the back surface.

[0159] Among them, the substrate is made of N-type monocrystalline silicon, the first doped layer is made of N-type doped polysilicon, and the first passivation layer is made of silicon oxide.

[0160] In this embodiment, the second semiconductor layer further includes a second passivation layer, and the second passivation layer is disposed on the side of the second doped layer facing the back surface.

[0161] In this embodiment, the second passivation layer is an a-Si:H(i) layer, and the second doped layer is made of an a-Si:H(p) layer.

[0162] Secondly, this embodiment provides a battery module, including the above-mentioned back contact battery.

[0163] Furthermore, this embodiment provides a photovoltaic system, including the above-mentioned battery module.

[0164] Embodiment 3

[0165] The difference between this embodiment and Embodiment 2 is that this embodiment does not provide a protective ink layer.

[0166] Embodiment 4

[0167] First of all, this embodiment discloses a back contact battery, including:

[0168] A substrate, the substrate includes a front surface and a back surface which are oppositely arranged, and the back surface has a plurality of first regions and second regions which are alternately arranged along a first direction;

[0169] A first semiconductor layer, disposed in the first region, including a first doped layer;

[0170] A second semiconductor layer, at least partially disposed in the second region, including a second doped layer, and the polarity of the second doped layer is opposite to the polarity of the first doped layer;

[0171] A TCO layer, including a first TCO segment disposed in the first region and a second TCO segment disposed in the second region, at least a part of the first TCO segment is electrically connected to the first doped layer, at least a part of the second TCO segment is electrically connected to the second doped layer, the first TCO segment and the second TCO segment are arranged at intervals and alternately in the first direction, and the first TCO segment and the second TCO segment include a main body, and a plurality of convex portions extending along a direction away from the main body are provided on the side walls at both ends of the main body in the first direction.

[0172] In this embodiment, the cross section of the convex portion is a single-peak structure or a multi-peak structure, the multi-peak structure includes a plurality of single-peak structures which are at least partially connected, and the single-peak structure is a sharp-peak structure or a hump-shaped structure.

[0173] In this embodiment, in the first direction, the relative distance h between the end of the convex portion far from the main body to which it is connected and the main body to which it is connected is:

[0174] h = a × w G

[0175] Wherein, w G is the width distance between the main body of the adjacent first TCO segment and the main body of the second TCO segment in the first direction, and a is 2.10%.

[0176] In this embodiment, in the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is 15 μm.

[0177] In this embodiment, the protrusion includes a first protrusion located on the first TCO segment. In the first direction, the relative distance h1 between the end of the first protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0178] h1 = b × w1

[0179] Wherein, w1 is the width distance of the main body to which the first protrusion is connected in the first direction, and b is 3.75%.

[0180] In this embodiment, the protrusion includes a second protrusion located on the second TCO segment. In the first direction, the relative distance h2 between the end of the second protrusion away from the main body to which it is connected and the main body to which it is connected is:

[0181] h2 = c × w2

[0182] Wherein, w1 is the width distance of the main body to which the second protrusion is connected in the first direction, and c is 3.75%.

[0183] In this embodiment, it further includes a protective ink layer. The protective ink layer includes a first ink portion and a second ink portion. At least part of the first ink portion and at least part of the second ink portion are provided on the side of the first TCO segment facing away from the substrate, and the first ink portion and the second ink portion are respectively provided at both ends of the first TCO segment in the first direction. The first ink portion and the second ink portion form a serrated edge on the side away from each other in the first direction, and both the first ink portion and the second ink portion are provided with a number of first protrusion units outside the edge of the first TCO segment.

[0184] In this embodiment, it further includes a protective ink layer. The protective ink layer includes a third ink portion and a fourth ink portion. At least part of the third ink portion and at least part of the fourth ink portion are provided on the side of the second TCO segment facing away from the substrate, and the third ink portion and the fourth ink portion are respectively provided at both ends of the second TCO segment in the first direction. The third ink portion and the fourth ink portion form a serrated edge on the side away from each other in the first direction, and both the third ink portion and the fourth ink portion are provided with a number of second protrusion units outside the edge of the second TCO segment.

[0185] In this embodiment, the second semiconductor layer is entirely disposed in the second region.

[0186] In this embodiment, the second semiconductor layer includes a first segment disposed in the first region and a second segment disposed in the second region. The first segment and the second segment are connected to each other. The first segment is disposed on the side of the first semiconductor layer facing away from the substrate, and an insulating protective layer is provided between the first segment and the first semiconductor layer. An avoidance hole is provided in the first region, and the avoidance hole penetrates through part of the first segment and part of the insulating protective layer. At least part of the first TCO segment is disposed in the avoidance hole and is in contact with the side of the first doped layer facing away from the substrate.

[0187] The insulating protective layer plays a role of isolation and protection, and the material of the insulating protective layer is PSG.

[0188] In this embodiment, the first TCO segment includes a first extension segment and a second extension segment connected to each other. The first extension segment is disposed in the avoidance hole and is in contact with the first doped layer. The second extension segment is disposed on the side of the second doped layer facing away from the substrate. In the thickness direction of the substrate, the relative distance between the second extension segment and the front surface is greater than the relative distance between the second TCO segment and the front surface. The second segment includes a parallel segment and a connection segment connected to each other. The parallel segment is parallel to and in contact with the second TCO segment. The connection segment is connected to the first segment, and at least part of the connection segment is not covered by the TCO layer.

[0189] In this embodiment, the first semiconductor layer further includes a first passivation layer, and the first passivation layer is disposed between the first doped layer and the back surface.

[0190] Among them, the material of the substrate is N-type single crystal silicon, the material of the first doped layer is N-type doped polysilicon, and the material of the first passivation layer is silicon oxide.

[0191] In this embodiment, the second semiconductor layer further includes a second passivation layer, and the second passivation layer is disposed on the side of the second doped layer facing the back surface.

[0192] In this embodiment, the second passivation layer is an a-Si:H(i) layer, and the material of the second doped layer is an a-Si:H(p) layer.

[0193] Secondly, this embodiment provides a battery assembly including the above-mentioned back-contact battery.

[0194] Furthermore, this embodiment provides a photovoltaic system including the above-mentioned battery assembly.

[0195] Comparative Example 1

[0196] The difference between this comparative example and Embodiment 1 is that the TCO layer of this comparative example does not have a protrusion, and this comparative example does not provide a protective ink layer.

[0197] Electrical performance test and yield test:

[0198] Take 100 batteries prepared in Examples 1 to 4 and Comparative Example 1 respectively, test their electrical performance, take the average value of the battery conversion efficiency of each group of batteries as the battery conversion efficiency of each group of batteries, and calculate the production yield. The test results are shown as follows:

[0199] Experimental group Battery conversion efficiency (%) Production yield (%) Example 1 26.20％ 90％ Example 2 26.32％ 92％ Example 3 26.31％ 90％ Example 4 26.41％ 95％ Comparative example 1 25.89％ 88％

[0200] The experimental results show that, compared with Comparative Example 1, the battery structures of Examples 1 to 4 of the present invention can effectively improve the battery conversion efficiency and the production yield.

[0201] In the description of this specification, the descriptions referring to terms such as "some embodiments", "implementation schemes", "exemplary", "examples", or "for example" etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiments or examples. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0202] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the technical content prompted above within the scope of the technical solution of the present invention. However, as long as it does not depart from the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A back contact battery, characterized in that, Comprising: A substrate, the substrate including a front surface and a back surface which are oppositely arranged, the back surface having a plurality of first regions and second regions alternately arranged in a first direction; A first semiconductor layer, disposed in the first region, including a first doped layer; A second semiconductor layer, at least partially disposed in the second region, including a second doped layer, the polarity of the second doped layer being opposite to the polarity of the first doped layer; A TCO layer, including a first TCO segment disposed in the first region and a second TCO segment disposed in the second region, at least a partial region of the first TCO segment being electrically connected to the first doped layer, at least a partial region of the second TCO segment being electrically connected to the second doped layer, the first TCO segment and the second TCO segment being arranged in a spaced and staggered manner in the first direction, and the first TCO segment and / or the second TCO segment including a main body, and a plurality of protrusions extending in a direction away from the main body being provided on both side walls of the main body in the two ends in the first direction.

2. The back contact battery according to claim 1, characterized in that, The cross section of the protrusion is of a single-peak structure or a multi-peak structure, the multi-peak structure including a plurality of single-peak structures which are at least partially connected, and the single-peak structure being a spike-like structure or a hump-like structure.

3. A back-contact battery according to claim 1, characterized in that, In the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is: h = a × w G Wherein, w G is the width distance between the main body of the adjacent first TCO segment and the main body of the second TCO segment in the first direction, and a is 0.7% to 3.5%.

4. A back-contact battery according to claim 1, characterized in that, In the first direction, the relative distance h between the end of the protrusion away from the main body to which it is connected and the main body to which it is connected is 5 μm to 25 μm.

5. A back-contact battery according to claim 1, wherein The protrusion includes a first protrusion located on the first TCO segment. In the first direction, the relative distance h1 between the end of the first protrusion away from the main body to which it is connected and the main body to which it is connected is: h1 = b × w1 In the formula, w1 is the width distance of the main body to which the first protrusion is connected in the first direction, and b is 1% to 6.25%.

6. A back-contact battery according to claim 1, wherein The protrusion includes a second protrusion located on the second TCO segment. In the first direction, the relative distance h2 between the end of the second protrusion away from the main body to which it is connected and the main body to which it is connected is: h2 = c × w2 In the formula, w1 is the width distance of the main body to which the second protrusion is connected in the first direction, and c is 1% to 6.25%.

7. A back-contact battery according to claim 1, characterized in that, It further includes a protective ink layer, The protective ink layer includes a first ink portion and a second ink portion. At least a partial region of the first ink portion and at least a partial region of the second ink portion are disposed on the side of the first TCO segment facing away from the substrate, and the first ink portion and the second ink portion are respectively disposed at the two ends of the first TCO segment in the first direction. The first ink portion and the second ink portion form a serrated edge on the side away from each other in the first direction, and a plurality of first protrusion units disposed outside the edge of the first TCO segment are provided on both the first ink portion and the second ink portion; and / or, The protective ink layer includes a third ink portion and a fourth ink portion. At least part of the third ink portion and at least part of the fourth ink portion are disposed on the side of the second TCO segment facing away from the substrate, and the third ink portion and the fourth ink portion are respectively disposed at two ends of the second TCO segment in a first direction. The third ink portion and the fourth ink portion form a serrated edge on the side away from each other in the first direction, and a plurality of second protrusion units are provided on both the third ink portion and the fourth ink portion outside the edge of the second TCO segment.

8. A back-contact battery according to claim 1, wherein, The second semiconductor layer includes a first segment disposed in the first region and a second segment disposed in the second region. The first segment is connected to the second segment. The first segment is disposed on the side of the first semiconductor layer facing away from the substrate, and an insulating protective layer is provided between the first segment and the first semiconductor layer. An avoidance hole is provided in the first region, and the avoidance hole penetrates through part of the first segment and part of the insulating protective layer. At least part of the first TCO segment is disposed in the avoidance hole and is in contact with the side of the first doping layer facing away from the substrate.

9. A back-contact battery according to claim 8, characterized in that, The first TCO segment includes a first extension segment and a second extension segment connected to each other. The first extension segment is disposed in the avoidance hole and is in contact with the first doping layer. The second extension segment is disposed on the side of the second doping layer facing away from the substrate. In the thickness direction of the substrate, the relative distance between the second extension segment and the front surface is greater than or less than the relative distance between the second TCO segment and the front surface. The second segment includes a parallel segment and a connection segment connected to each other. The parallel segment is parallel to and in contact with the second TCO segment. The connection segment is connected to the first segment, and at least part of the connection segment is not covered by the TCO layer.

10. A back-contact battery according to claim 9, characterized in that, The first semiconductor layer further includes a first passivation layer disposed between the first doping layer and the back surface; and / or, The second semiconductor layer further includes a second passivation layer disposed on the side of the second doping layer facing the back surface.

11. A battery assembly, characterized in that, Comprising a back-contact battery according to any one of claims 1 to 10.

12. A photovoltaic system, characterized in that, Comprising a battery assembly according to claim 11.

Images