Back contact solar cell, cell module and photovoltaic system

Abstract

The utility model is applicable to the technical field of solar cells, and provides a back contact solar cell, a cell assembly and a photovoltaic system, the back contact solar cell comprises a silicon substrate, and the back surface of the silicon substrate comprises a P-type doped region, an N-type doped region and an isolation region; the P-type doped region is provided with a first suede, the first suede comprises a first pyramid-like structure, and / or the N-type doped region is provided with a second suede, the second suede comprises a second pyramid-like structure, and / or the isolation region is provided with a third suede, and the third suede comprises a third pyramid-like structure; the average base angle of the first pyramid-like structure is smaller than that of the second pyramid-like structure; and / or the average base angle of the first pyramid structure is smaller than the average base angle of the third pyramid structure; and / or the average base angle of the second pyramid structure is smaller than the average base angle of the third pyramid structure. The back contact solar cell provided by the utility model can improve the utilization rate of sunlight, and realizes good passivation performance of the back surface, thereby improving the efficiency of the cell.

Description

TECHNICAL FIELD

[0001] The utility model relates to solar cell technical field especially relates to a back contact solar cell, battery assembly and photovoltaic system. BACKGROUND

[0002] The back contact (Interdigitated back contact, IBC) solar cell, namely the interdigital back contact solar cell, the positive / negative electrode grid line is designed in the back of the cell, makes the front surface avoid the shelter of metal grid line completely, eliminates the optical loss brought by electrode grid line shelter, and the electrode grid line can be designed wider than the prior art, reduces the series resistance loss, thereby greatly improves the cell conversion efficiency. In addition, due to the design of the electrode grid line on the front surface of the cell, the product appearance is more beautiful, is suitable for a variety of application scenarios.

[0003] In the prior art, the back surface of the silicon substrate of the back contact solar cell is usually polished by alkali or acid to form a polishing surface, so as to increase the uniformity of the passivation contact structure and improve the overall passivation quality, but the reflection of the back surface of the silicon substrate to the sunlight entering the silicon substrate from the front surface is reduced, the sunlight entering the silicon substrate from the front surface of the silicon substrate is easy to escape directly from the back surface of the silicon substrate, resulting in low solar light utilization rate of the cell and difficult to improve the cell efficiency. UTILITY MODEL CONTENTS

[0004] The utility model provides a back contact solar cell, aims at solving the low solar light utilization rate of the back contact solar cell in prior art and the problem of difficult to improve the cell efficiency.

[0005] The utility model is such a realization that a back contact solar cell is provided, which comprises a silicon substrate, the silicon substrate comprises a front surface and a back surface arranged oppositely, the back surface comprises a P-type doped region, an N-type doped region and an isolation region arranged between the P-type doped region and the N-type doped region, at least two of the P-type doped region, the N-type doped region and the isolation region are provided with a textured surface; the P-type doped region is provided with a first textured surface, the first textured surface comprises a plurality of first pyramidal structures, and / or the N-type doped region is provided with a second textured surface, the second textured surface comprises a plurality of second pyramidal structures, and / or the isolation region is provided with a third textured surface, the third textured surface comprises a plurality of third pyramidal structures.

[0006] The average base angle of the first pyramidal structure is smaller than the average base angle of the second pyramidal structure; and / or the average base angle of the first pyramidal structure is smaller than the average base angle of the third pyramidal structure; and / or the average base angle of the second pyramidal structure is smaller than the average base angle of the third pyramidal structure.

[0007] Preferably, the P-type doped region is provided with the first texture, the N-type doped region is provided with the second texture, and the isolation region is provided as a non-textured surface.

[0008] Preferably, the P-type doped region is provided with the first texture, the isolation region is provided with the third texture, and the N-type doped region is provided as a non-textured surface.

[0009] Preferably, the N-type doped region is provided with the second texture, the isolation region is provided with the third texture, and the P-type doped region is provided as a non-textured surface.

[0010] Preferably, the P-type doped region is provided with the first texture, the N-type doped region is provided with the second texture, and the isolation region is provided with the third texture.

[0011] Preferably, the average base angle of the second type of pyramid structure is greater than the average base angle of the first type of pyramid structure by more than 5°; and / or, the average base angle of the third type of pyramid structure is greater than the average base angle of the second type of pyramid structure by more than 5°; and / or, the average base angle of the third type of pyramid structure is greater than the average base angle of the first type of pyramid structure by more than 10°.

[0012] Preferably, the average base angle of the first type of pyramid structure is 10-60°; the average base angle of the second type of pyramid structure is 20-70°, and the average base angle of the third type of pyramid structure is 30-85°.

[0013] Preferably, the average base angle of the first type of pyramid structure is 15-45°; the average base angle of the second type of pyramid structure is 20-55°, and the average base angle of the third type of pyramid structure is 40-75°.

[0014] Preferably, the top of the first type of pyramid structure is provided as a first circular arc surface; and / or, the top of the second type of pyramid structure is provided as a second circular arc surface.

[0015] Preferably, the curvature of the first circular arc surface is smaller than the curvature of the second circular arc surface.

[0016] Preferably, the connection between two adjacent first type of pyramid structures is provided as a third circular arc surface, and / or, the connection between two adjacent second type of pyramid structures is provided as a fourth circular arc surface.

[0017] Preferably, the curvature of the third circular arc surface is smaller than the curvature of the fourth circular arc surface.

[0018] Preferably, the top of the third type of pyramid structure is provided as a sharp point, and the connection between two adjacent third type of pyramid structures is provided as a sharp point.

[0019] Preferably, the height of the first type of pyramid structure is less than the height of the second type of pyramid structure.

[0020] Preferably, the height of the second type of pyramid structure is less than the height of the third type of pyramid structure.

[0021] Preferably, the roughness of the side surface of the first type of pyramid structure is less than the roughness of the side surface of the second type of pyramid structure.

[0022] Preferably, the roughness of the side surface of the second type of pyramid structure is less than the roughness of the side surface of the third type of pyramid structure.

[0023] Preferably, the front surface of the silicon substrate is provided with a fourth textured surface.

[0024] The utility model also provides a kind of battery assembly, including above-mentioned back contact solar cell.

[0025] The utility model also provides a kind of photovoltaic system, including above-mentioned battery assembly.

[0026] The back contact solar cell provided by the utility model is provided with a textured surface in at least two of the P-type doped region, the N-type doped region and the isolation region on the back surface of the silicon substrate. On the one hand, the sunlight entering the silicon substrate from the front surface of the silicon substrate is reflected by the textured surface provided in the P-type doped region, the N-type doped region and the isolation region, so that the sunlight is reflected multiple times within the silicon substrate, the sunlight directly emitted from the back surface of the silicon substrate is reduced, the reflection path of the sunlight within the silicon substrate is increased, the absorption of the solar cell to the sunlight is increased, and the utilization rate of the back contact solar cell to the sunlight is greatly improved.

[0027] On the other hand, by controlling the average base angle of the first type of pyramid structure to be less than the average base angle of the second type of pyramid structure, and / or controlling the average base angle of the first type of pyramid structure to be less than the average base angle of the third type of pyramid structure, and / or controlling the average base angle of the second type of pyramid structure to be less than the average base angle of the third type of pyramid structure, the surface recombination loss of the back surface of the silicon substrate is reduced, the deposition of the film layer on the back surface of the silicon substrate is facilitated, the passivation performance of the film layer on the back surface is improved, the optical performance and the passivation performance of the back surface of the back contact solar cell are considered, the matching of the good optical performance and the good passivation performance of the cell is realized, and the cell efficiency is improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The utility model provides a kind of back contact solar cell's structural schematic view for embodiment of the utility model;

[0029] Figure 2The utility model provides a kind of structure schematic diagram of silicon substrate of back contact solar cell provided for the embodiment of the utility model;

[0030] Figure 3 A partial structure schematic diagram of the first textured surface of back contact solar cell provided for the embodiment of the utility model;

[0031] Figure 4 A partial structure schematic diagram of the second textured surface of back contact solar cell provided for the embodiment of the utility model;

[0032] Figure 5 A partial structure schematic diagram of the third textured surface of back contact solar cell provided for the embodiment of the utility model;

[0033] Figure 6 The structure schematic diagram of silicon substrate of second back contact solar cell provided for the embodiment of the utility model;

[0034] Figure 7 The structure schematic diagram of silicon substrate of third back contact solar cell provided for the embodiment of the utility model;

[0035] Figure 8 The structure schematic diagram of silicon substrate of fourth back contact solar cell provided for the embodiment of the utility model;

[0036] Figure 9 A partial structure schematic diagram of the fourth textured surface of back contact solar cell provided for the embodiment of the utility model;

[0037] Figure 10 The structure schematic diagram of silicon substrate of fifth back contact solar cell provided for the embodiment of the utility model;

[0038] Figure 11 Another partial structure schematic diagram of the first textured surface of back contact solar cell provided for the embodiment of the utility model;

[0039] Figure 12 Another partial structure schematic diagram of the second textured surface of back contact solar cell provided for the embodiment of the utility model. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the utility model clearer, the utility model will be described in further detail below in combination with the drawings and examples. The examples of the examples are shown in the drawings, wherein the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions throughout. The examples described below with reference to the drawings are exemplary and are used only to explain the utility model and cannot be understood as limiting the utility model. In addition, it should be understood that the specific examples described herein are only used to explain the utility model and do not limit the utility model.

[0041] In the description of the utility model, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "back", "front" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the utility model.

[0042] In the utility model, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature in the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature in the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature in the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.

[0043] The following disclosure provides many different embodiments or examples for implementing different structures of the utility model. In order to simplify the disclosure of the utility model, the components and settings of the specific examples are described below. Of course, they are only examples and the purpose is not to limit the utility model. In addition, the utility model can repeatedly refer to numerals and / or reference letters in different examples, and such repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the utility model provides examples of various specific processes and materials, but those skilled in the art can realize the application of other processes and / or the use of other materials.

[0044] The back contact solar cell provided by the utility model is characterized in that the back surface of the silicon substrate is provided with a P-type doped area, an N-type doped area and an isolation area, and at least two of the P-type doped area, the N-type doped area and the isolation area are provided with a rough surface, so that the sunlight entering the silicon substrate from the front surface of the silicon substrate is reflected in the silicon substrate for multiple times, the sunlight directly emitted from the back surface of the silicon substrate is reduced, the reflection path of the sunlight in the silicon substrate is increased, the absorption of the sunlight by the solar cell is increased, and the utilization rate of the sunlight by the back contact solar cell is greatly improved.

[0045] Please refer to Figures 1-5 The utility model provides a kind of back contact solar cell, including silicon substrate 1, silicon substrate 1 includes oppositely arranged front and back, back includes P-type doped area 2, N-type doped area 3 and isolation area 4 between P-type doped area 2 and N-type doped area 3, at least two of P-type doped area 2, N-type doped area 3, isolation area 4 are provided with rough surface;P-type doped area 2 is provided with first rough surface 21, and first rough surface 21 includes several first class pyramid structure 211;And / or, N-type doped area 3 is provided with second rough surface 31, and second rough surface 31 includes several second class pyramid structure 311;And / or, isolation area 4 is provided with third rough surface 41, and third rough surface 41 includes several third class pyramid structure 411.

[0046] The average base angle of the first class pyramid structure 211 is less than the average base angle of the second class pyramid structure 311;And / or, the average base angle of the first class pyramid structure 211 is less than the average base angle of the third class pyramid structure 411;And / or, the average base angle of the second class pyramid structure 311 is less than the average base angle of the third class pyramid structure 411.

[0047] The utility model discloses a silicon substrate 1 includes the front and back of opposite setting, and the front of silicon substrate 1 is the one side of back contact solar cell when working to face the sunlight, and the back of silicon substrate 1 is the one side of back contact solar cell when working to deviate the sunlight. P type doped area 2 is the region of setting P type doped layer, and N type doped area 3 is the region of setting N type doped layer, and the isolation area 4 is located between two adjacent P type doped area 2 and N type doped area 3 for the physical isolation P type doped area 2 and N type doped area 3. Among them, the specific quantity of P type doped area 2 and N type doped area 3 is not limited. Optionally, P type doped area 2 and N type doped area 3 are multiple, and P type doped area 2 and N type doped area 3 are sequentially and alternately spaced, and the isolation area 4 is arranged between the two adjacent P type doped area 2 and N type doped area 3.

[0048] In the embodiment of the utility model, at least two of P type doped area 2, N type doped area 3 and isolation area 4 are provided with a suede, specifically, P type doped area 2, N type doped area 3 and isolation area 4 can all be provided with a suede, or P type doped area 2 and N type doped area 3 are provided with a suede, and isolation area 4 is not provided with a suede, or N type doped area 3 and isolation area 4 are provided with a suede, and P type doped area 2 is not provided with a suede, or N type doped area 3 and isolation area 4 are provided with a suede, and P type doped area 2 is not provided with a suede.

[0049] In the embodiment of the utility model, P type doped area 2 is provided with a first suede 21, which can be understood as that P type doped area 2 can only have a part of the region provided with a first suede 21, or all the regions of P type doped area 2 can be provided with a first suede 21. When P type doped area 2 can only have a part of the region provided with a first suede 21, each P type doped area 2 can be provided with a first suede 21, but at least one P type doped area 2 has a part of the region provided with a non-suede region, that is, at least one P type doped area 2 has a part of the region provided as a polishing surface, or only a part of the P type doped area 2 is provided with a first suede 21, and the other part of the P type doped area 2 is a non-suede region, that is, the other part of the P type doped area 2 is provided as a polishing surface. In this way, P type doped area 2 is designed by combining a first suede 21 and a polishing surface, the utilization rate of P type doped area 2 to sunlight is improved by using a first suede 21, the surface recombination loss of P type doped area 2 is reduced by using a polishing surface, and the passivation performance of the back film layer of P type doped area 2 is improved, and the battery efficiency is improved.

[0050] In the embodiment of the utility model, N type doped area 3 is provided with second nap 31, can understand, N type doped area 3 can only have partial area provided with second nap 31, also can have all the area of all N type doped area 3 provided with second nap 31. When N type doped area 3 can only have partial area provided with second nap 31, can be, each N type doped area 3 is provided with second nap 31, but at least one N type doped area 3 has partial area provided with non-nap area, that is, at least one N type doped area 3 has partial area and is provided as polishing surface;Or, only partial quantity N type doped area 3 is provided with second nap 31, another partial quantity N type doped area 3 is non-nap area, that is, another partial quantity N type doped area 3 is provided as polishing surface. In this way, N type doped area 3 utilizes the combination design of second nap 31 and polishing surface, utilizes second nap 31 to improve the utilization rate of N type doped area 3 to sunlight, simultaneously utilizes polishing surface to reduce the surface recombination loss of N type doped area 3, and it is favorable to improve the passivation performance of the back film layer of N type doped area 3, and it is favorable to improve the cell efficiency.

[0051] The isolation region 4 is provided with the third nap 41, and can be understood that the isolation region 4 can only have partial area provided with the third nap 41, or all the area of the entire isolation region 4 is provided with the third nap 41.

[0052] The plurality of first pyramidal structures 211 of the first nap 21 can also be arranged in a linear array, or can be arranged irregularly. Similarly, the plurality of second pyramidal structures 311 of the second nap 31 can also be arranged in a linear array, or can be arranged irregularly. The plurality of third pyramidal structures 411 of the third nap 41 can also be arranged in a linear array, or can be arranged irregularly.

[0053] The first pyramidal structure 211, the second pyramidal structure 311 and the third pyramidal structure 411 are all pyramidal structures with a top or truncated pyramidal structures; wherein, the pyramidal structure can be a pyramidal structure with three sides and one bottom, or the pyramidal structure can be a pyramidal structure with four sides and one bottom; or, the pyramidal structure can be a pyramidal structure with five sides and one bottom; or, the pyramidal structure can be a pyramidal structure with six sides and one bottom; of course, the pyramidal structure can also be a pyramidal structure with more number of sides and one bottom.

[0054] When the angles between each side surface of a pyramidal structure and its base are equal, the base angle of the pyramidal structure can be determined by measuring the angle between any one side surface and its base. However, the angles between the side surfaces and base of a pyramidal structure may not be equal. In this case, the average angle between the side surfaces and base is taken as the base angle of the pyramidal structure.

[0055] Among them, such as Figure 3 As shown, the base angle B of the first type of pyramidal structure 211 is the angle between the side surface of the first type of pyramidal structure 211 and the base surface of the first type of pyramidal structure 211, and the base surface is a plane perpendicular to the thickness direction of the silicon substrate 1. Figure 4 As shown, the base angle C of the second type of pyramidal structure 311 is the angle between the side surface of the second type of pyramidal structure 311 and the base surface of the second type of pyramidal structure 311, and the base surface is a plane perpendicular to the thickness direction of the silicon substrate 1. Figure 5 As shown, the base angle D of the third type of pyramid structure 411 is the angle between the side surface of the third type of pyramid structure 411 and the base surface of the third type of pyramid structure 411, and the base surface is a plane perpendicular to the thickness direction of the silicon substrate 1.

[0056] In this embodiment of the present invention, the average base angle of the first type of pyramidal structure 211 is the average base angle of all the first type of pyramidal structures 211 on the first velvet surface 21; the average base angle of the second type of pyramidal structure 311 is the average base angle of a preset number of second type of pyramidal structures 311 in the target area of ​​the second velvet surface 31; and the average base angle of the third type of pyramidal structure 411 is the average base angle of all the third type of pyramidal structures 411 on the third velvet surface 41.

[0057] Alternatively, the average base angle of the first type of pyramidal structure 211 can be the average base angle of a first preset number of first type of pyramidal structures 211 in the first pile surface 21; the average base angle of the second type of pyramidal structure 311 can be the average base angle of a first preset number of second type of pyramidal structures 311 in the second pile surface 31; and the average base angle of the third type of pyramidal structure 411 can be the average base angle of a first preset number of third type of pyramidal structures 411 in the third pile surface 41. Preferably, the first preset number is 2 to 10, and the average base angle of 2 to 10 first type of pyramidal structures 211 in the first pile surface 21 is measured as the average base angle of the first type of pyramidal structure 211; the average base angle of 2 to 10 second type of pyramidal structures 311 in the second pile surface 31 is measured as the average base angle of the second type of pyramidal structure 311; and the average base angle of 2 to 10 third type of pyramidal structures 411 in the third pile surface 41 is measured as the average base angle of the third type of pyramidal structure 411.

[0058] The average base angle of the first type of pyramid structure 211 can be an average value of base angles of a second preset number of first type of pyramid structures 211 arranged in the first direction and having the highest height in a target region of the first pile surface 21. The average base angle of the second type of pyramid structure 311 can be an average value of base angles of a second preset number of second type of pyramid structures 311 arranged in the first direction and having the highest height in a target region of the second pile surface 31. The average base angle of the third type of pyramid structure 411 can be an average value of base angles of a second preset number of third type of pyramid structures 411 arranged in the first direction and having the highest height in a target region of the third pile surface 41. The target region can be a rectangular region of 20 μm x 30 μm, and the second preset number can be 3-10.

[0059] For example, when comparing the average base angles of the first type of pyramid structure 211, the second type of pyramid structure 311, and the third type of pyramid structure 411, a rectangular region of 20 μm x 30 μm is taken as a target region on the first pile surface 21, the second pile surface 31, and the third pile surface 41, respectively. The base angles of three first type of pyramid structures 211 arranged in the first direction and having the highest height in the target region of the first pile surface 21 are measured, and an average value of the base angles of the three first type of pyramid structures 211 is calculated as the average base angle of the first type of pyramid structure 211. The base angles of three second type of pyramid structures 311 arranged in the first direction and having the highest height in the target region of the second pile surface 31 are measured, and an average value of the base angles of the three second type of pyramid structures 311 is calculated as the average base angle of the second type of pyramid structure 311. The base angles of three third type of pyramid structures 411 arranged in the first direction and having the highest height in the target region of the third pile surface 41 are measured, and an average value of the base angles of the three third type of pyramid structures 411 is calculated as the average base angle of the third type of pyramid structure 411. Of course, other areas can be taken as target regions, and other numbers of pyramid structures can be compared.

[0060] The utility model discloses an embodiment, through being provided with the rough surface in the back of P type doped area 2, N type doped area 3 and isolation area 4 of the silicon substrate 1 of back contact solar energy, one, the sunlight that enters the silicon substrate 1 from the front of silicon substrate 1 is reflected in the silicon substrate 1 by the rough surface of the P type doped area 2, N type doped area 3 and isolation area 4 at least two settings, can reduce the sunlight that directly shoots from the back of silicon substrate 1, can increase the reflection path of sunlight in the silicon substrate 1, increase the absorption of solar cell to sunlight, greatly promoted the utilization of back contact solar cell to sunlight, on the other hand, the average base angle of first pyramid structure 211 is controlled to be less than the average base angle of second pyramid structure 311 under the condition that P type doped area 2, N type doped area 3 are provided with the rough surface, the average base angle of first pyramid structure 211 is controlled to be less than the average base angle of third pyramid structure 411 under the condition that P type doped area 2 and isolation area 4 are provided with the rough surface, the average base angle of second pyramid structure 311 is controlled to be less than the average base angle of third pyramid structure 411 under the condition that N type doped area 3 and isolation area 4 are provided with the rough surface, the average base angle of first pyramid structure 211 is less than the average base angle of second pyramid structure 311, and the average base angle of second pyramid structure 311 is less than the average base angle of third pyramid structure 411 under the condition that P type doped area 2, N type doped area 3 are provided with second rough surface 31, and isolation area 4 are all provided with the rough surface, can reduce the surface recombination loss of the back of silicon substrate 1, and it is favorable that the film layer deposition of the back of silicon substrate 1 and it is favorable to improve the passivation performance of the film layer of the back, so as to give consideration to the good optical performance of back contact solar cell and the good passivation performance of cell back, realize the matching of the good optical performance of cell and the good passivation performance, and further improve the cell efficiency.

[0061] Please refer to Figure 2 , as an embodiment of the utility model, P type doped area 2 is provided with first rough surface 21, N type doped area 3 is provided with second rough surface 31, and isolation area 4 is provided with third rough surface 41.

[0062] In the embodiment, the average base angle of first pyramid structure 211 is less than the average base angle of second pyramid structure 311, and the average base angle of second pyramid structure 311 is less than the average base angle of third pyramid structure 411.

[0063] The utility model discloses an embodiment, set up first napping 21 in P type doped area 2 on the back of silicon base 1, set up second napping 31 in N type doped area 3, set up third napping 41 in isolation area 4, utilize first napping 21, second napping 31, third napping 41 jointly to the sunlight of the front of silicon base 1 into the sunlight of silicon base 1 reflection, the sunlight of the front of silicon base 1 into the sunlight of silicon base 1 reflection in silicon base 1 inside back and forth multiple times, can increase the reflection path of sunlight in silicon base 1, reduce the sunlight direct from the back and escape, reduce the transmissivity of sunlight from the back, increase the absorption of solar cell to sunlight, greatly promoted the utilization of the back contact solar cell to sunlight. Simultaneously, since the average base angle of first pyramid structure 211 is less than the average base angle of second pyramid structure 311, and the average base angle of second pyramid structure 311 is less than the average base angle of third pyramid structure 411, it is favorable to reduce the surface recombination loss of the back of silicon base 1, realizes the balance of the good optical performance and the good passivation performance of the back of battery two aspects, and moreover, realizes the reflection performance of first napping 21, second napping 31, third napping 41 to the front transmission light increasing in turn, and the passivation performance of first napping 21, second napping 31, third napping 41 surface decreases in turn, it is favorable to realize the good matching of the optical performance and passivation performance of P type doped area 2, N type doped area 3, isolation area 4, further promotes the battery efficiency.

[0064] Please refer to Figure 6 As another embodiment of the utility model, P type doped area 2 is provided with first napping 21, N type doped area 3 is provided with second napping 31, and isolation area 4 is provided with non-napping 200.

[0065] In the embodiment, only P type doped area 2 and N type doped area 3 are provided with napping, and isolation area 4 is provided with non-napping 200, so that the surface recombination loss of isolation area 4 can be reduced, and the optical and passivation effects of the back can be balanced. The average base angle of first pyramid structure 211 is less than the average base angle of second pyramid structure 311. The non-napping 200 provided on the isolation area 4 can be a polished surface.

[0066] In the embodiment, the first rough surface 21 is arranged on the P-type doped region 2 on the back surface of the silicon substrate 1, and the second rough surface 31 is arranged on the N-type doped region 3, the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1 is reflected by the first rough surface 21 and the second rough surface 31, the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1 is reflected back and forth in the silicon substrate 1 for multiple times through the first rough surface 21 and the second rough surface 31, the reflection path of the sunlight in the silicon substrate 1 is increased, the sunlight directly escaping from the back surface is reduced, the transmittance of the sunlight from the back surface is reduced, the absorption of the sunlight by the solar cell is increased, and the utilization rate of the sunlight by the back contact solar cell is greatly improved. Meanwhile, the average base angle of the first type of pyramid structure 211 is smaller than the average base angle of the second type of pyramid structure 311, the surface of the P-type doped region 2 is relatively flat compared with the surface of the N-type doped region 3, the surface recombination loss of the P-type doped region 2 is reduced, the passivation effect of the P-type doped region 2 is improved, and the balance between the passivation effect and the optical performance of the P-type doped region 2 and the N-type doped region 3 is realized.

[0067] Please refer to Figure 7 As another embodiment of the utility model, the P-type doped region 2 is provided with the first rough surface 21, the isolation region 4 is provided with the third rough surface 41, and the N-type doped region 3 is provided with the non-rough surface 200.

[0068] In the embodiment, only the P-type doped region 2 and the isolation region 4 are provided with the rough surface, and the N-type doped region 3 is provided with the non-rough surface, so that the surface recombination loss of the N-type doped region 3 is reduced, the passivation effect of the N-type doped region 3 is improved, and the balance between the optical performance and the passivation effect of the back surface is realized. At this time, the average base angle of the first type of pyramid structure 211 is smaller than the average base angle of the third type of pyramid structure 411. The non-rough surface 200 arranged on the isolation region 4 can be a polished surface.

[0069] In the embodiment, the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1 is reflected by the first rough surface 21 and the third rough surface 41, the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1 is reflected back and forth in the silicon substrate 1 for multiple times through the first rough surface 21 and the third rough surface 41, the reflection path of the sunlight in the silicon substrate 1 is increased, the sunlight directly escaping from the back surface is reduced, the transmittance of the sunlight from the back surface is reduced, the absorption of the sunlight by the solar cell is increased, and the utilization rate of the sunlight by the back contact solar cell is greatly improved. Meanwhile, the average base angle of the first type of pyramid structure 211 is smaller than the average base angle of the third type of pyramid structure 411, the rough surface of the P-type doped region 2 is relatively flat compared with the rough surface of the isolation region 4, the surface recombination loss of the P-type doped region 2 is reduced, the passivation effect of the P-type doped region 2 is improved, and the balance between the passivation effect and the optical performance of the P-type doped region 2 is considered.

[0070] Please refer to Figure 8As another embodiment of the utility model, the N-type doped region 3 is provided with a second rough surface 31, the isolation region 4 is provided with a third rough surface 41, and the P-type doped region 2 is provided with a non-rough surface 200.

[0071] In the embodiment, only the N-type doped region 3 and the isolation region 4 are provided with rough surfaces, and the P-type doped region 2 is provided with a non-rough surface, so that the surface recombination loss of the P-type doped region 2 can be reduced, and the optical performance and passivation effect of the back surface can be balanced. At this time, the average base angle of the second type of pyramid structure 311 is smaller than the average base angle of the third type of pyramid structure 411. The non-rough surface 200 provided on the P-type doped region 2 can be a polished surface.

[0072] In the embodiment, the second rough surface 31 and the third rough surface 41 are used to reflect the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1, and the sunlight entering the silicon substrate 1 from the front surface of the silicon substrate 1 is reflected multiple times inside the silicon substrate 1 through the second rough surface 31 and the third rough surface 41, so that the reflection path of the sunlight inside the silicon substrate 1 can be increased, the sunlight directly escaping from the back surface can be reduced, the transmittance of the sunlight from the back surface can be reduced, the absorption of the solar cell to the sunlight can be increased, and the utilization rate of the back contact solar cell to the sunlight can be greatly improved. At the same time, since the average base angle of the second type of pyramid structure 311 is smaller than the average base angle of the third type of pyramid structure 411, the rough surface of the N-type doped region 3 is relatively flat compared to the rough surface of the isolation region 4, which is beneficial to reducing the surface recombination loss caused by the rough surface of the N-type doped region 3 and improving the passivation effect of the N-type doped region 3, and the passivation effect and optical performance of the N-type doped region 3 are considered. Moreover, the P-type doped region 2 is provided with a non-rough surface, so that the good passivation effect of the P-type doped region 2 can be maintained, the optical performance and passivation performance of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 can be well matched, and the battery efficiency can be further improved.

[0073] Please refer to Figure 1 and Figure 2 As an embodiment of the utility model, the front surface of the silicon substrate 1 is provided with a fourth rough surface 10.

[0074] In the embodiment of the utility model, the front surface of the silicon substrate 1 is provided with a fourth rough surface 10 in at least a partial region, so as to reduce the light reflectivity of the front surface of the silicon substrate 1. The front surface of the silicon substrate 1 can be provided with a fourth rough surface 10 only in a partial region, or the front surface of the silicon substrate 1 can be provided with a fourth rough surface 10 in an entire region. Preferably, the front surface of the silicon substrate 1 is provided with a fourth rough surface 10 in an entire region.

[0075] As Figure 9As shown, in the embodiment of the utility model, the fourth nap 10 includes several fourth type pyramid structures 101, the bottom angle A of fourth type pyramid structure 101 is the angle between the side surface of fourth type pyramid structure 101 and the bottom surface of fourth type pyramid structure 101, the arrangement mode of several fourth type pyramid structures 101 is not limited, can be linear array setting, also can be irregular arrangement, and adjacent fourth type pyramid structure 101 can also be stacked.

[0076] Preferably, the average bottom angle of the first type pyramid structure 211, the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the third type pyramid structure 411 are all less than the average bottom angle of the fourth type pyramid structure 101, so that the sunlight entering the fourth nap 10 on the front surface of the silicon substrate 1 can be reflected into the silicon substrate 1 as much as possible through the first nap 21 or the second nap 31 or the third nap 41, which can further improve the utilization rate of sunlight and further improve the battery efficiency. Preferably, the difference between the average bottom angle of the fourth type pyramid structure 101 and the average bottom angle of the first type pyramid structure 211, the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the third type pyramid structure 411 is greater than 10°, which can further increase the sunlight reflection path, further improve the utilization rate of sunlight, and further improve the battery efficiency. The calculation of the average bottom angle of the fourth type pyramid structure 101 is the same as that of the average bottom angle of the first type pyramid structure 211, the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the third type pyramid structure 411, and will not be repeated here to save space.

[0077] As an embodiment of the utility model, the difference between the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the first type pyramid structure 211 is greater than 5°.

[0078] In the embodiment, under the premise of improving the utilization rate of sunlight by the P-type doped region 2 and the N-type doped region 3, the difference between the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the first type pyramid structure 211 is greater than 5°, so that the P-type doped region 2 and the N-type doped region 3 have reasonable differences in optical performance and passivation performance, thereby balancing the optical performance and passivation performance of the P-type doped region 2 and the N-type doped region 3, and realizing further optimization design of battery efficiency. For example, the difference between the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the first type pyramid structure 211 can be 5-15°.

[0079] As an embodiment of the utility model, the difference between the average bottom angle of the second type pyramid structure 311 and the average bottom angle of the third type pyramid structure 411 is greater than 5°.

[0080] In the embodiment, the average base angle of the third type of pyramid structure 411 and the average base angle of the second type of pyramid structure 311 are controlled to have a difference greater than 5° in the case that the N-type doped region 3 and the isolation region 4 are provided with a textured surface, so that the N-type doped region 3 and the isolation region 4 have a reasonable difference in optical performance and passivation performance, thereby well balancing the optical performance and passivation performance of the N-type doped region 3 and the isolation region 4, and achieving further optimization design of the battery efficiency. For example, the average base angle of the second type of pyramid structure 311 and the average base angle of the third type of pyramid structure 411 can have a difference of 5-15°.

[0081] As an embodiment of the utility model, the average base angle of the third type of pyramid structure 411 and the average base angle of the first type of pyramid structure 211 have a difference greater than 10°.

[0082] In the embodiment, the average base angle of the third type of pyramid structure 411 and the average base angle of the first type of pyramid structure 211 are controlled to have a difference greater than 10° in the case that the P-type doped region 2 and the isolation region 4 are provided with a textured surface, so that the P-type doped region 2 and the isolation region 4 have a reasonable difference in optical performance and passivation performance, thereby well balancing the optical performance and passivation performance of the P-type doped region 2 and the isolation region 4, and achieving further optimization design of the battery efficiency. For example, the average base angle of the third type of pyramid structure 411 and the average base angle of the first type of pyramid structure 211 can have a difference of 10-20°.

[0083] As an embodiment of the utility model, the average base angle of the second type of pyramid structure 311 and the average base angle of the first type of pyramid structure 211 have a difference greater than 5°; the average base angle of the third type of pyramid structure 411 and the average base angle of the second type of pyramid structure 311 have a difference greater than 5°; and the average base angle of the third type of pyramid structure 411 and the average base angle of the first type of pyramid structure 211 have a difference greater than 10°.

[0084] In the embodiment, the P-type doped region 2, the N-type doped region 3 and the isolation region 4 are all provided with a textured surface, and the average base angle of the pyramid structure of the textured surface of each region has the above-mentioned size relationship, so that the P-type doped region 2, the N-type doped region 3 and the isolation region 4 have a reasonable difference in optical performance, thereby well balancing the optical performance and passivation performance of the P-type doped region 2, the N-type doped region 3 and the isolation region 4, and achieving further optimization design of the battery efficiency.

[0085] As an embodiment of the utility model, the average base angle of the first type of pyramid structure 211 is 10-60°; the average base angle of the second type of pyramid structure 311 is 20-70°; and the average base angle of the third type of pyramid structure 411 is 30-85°.

[0086] In the embodiment, the average base angle of the first type of pyramid structure 211 is 10-60°; the average base angle of the second type of pyramid structure 311 is 20-70°, and the average base angle of the third type of pyramid structure 411 is 30-85°, so that the good optical performance and passivation effect of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 can be balanced.

[0087] As an embodiment of the utility model, the average base angle of the first type of pyramid structure 211 is 15-45°; the average base angle of the second type of pyramid structure 311 is 20-55°, and the average base angle of the third type of pyramid structure 411 is 40-75°.

[0088] In the embodiment, the average base angle of the first type of pyramid structure 211 can be any value in 15-45°, the average base angle of the second type of pyramid structure 311 can be any value in 20-55°, and the average base angle of the third type of pyramid structure 411 can be any value in 40-75°, as long as the average base angle of the first type of pyramid structure 211 is less than the average base angle of the second type of pyramid structure 311, and the average base angle of the second type of pyramid structure 311 is less than the average base angle of the third type of pyramid structure 411.

[0089] For example, the average base angle of the first type of pyramid structure 211 can be any value in 15°, 16°, 17°, 18°, 20°, 22°, 24°, 25°, 28°, 30°, 32°, 35°, 38°, 40°, 42°, 45°.

[0090] For example, the average base angle of the second type of pyramid structure 311 can be any value in 20°, 21°, 22°, 23°, 25°, 27°, 29°, 30°, 35°, 38°, 40°, 42°, 45°, 48°, 49°, 50°, 52°, 54°, 55°.

[0091] For example, the average base angle of the third type of pyramid structure 411 can be any value in 40°, 42°, 45°, 48°, 50°, 52°, 55°, 57°, 58°, 60°, 61°, 63°, 65°, 70°, 75°.

[0092] In the embodiment, the average base angle of the first type of pyramid structure 211 is 15-45°; the average base angle of the second type of pyramid structure 311 is 20-55°, and the average base angle of the third type of pyramid structure 411 is 40-65°, so that the good optical performance and passivation effect of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 can be further balanced.

[0093] As an embodiment of the utility model, the average base angle of the fourth type of pyramid structure 101 is 50-85 °. More sunlight can enter the inside of the silicon substrate 1, the reflection of the solar cell front surface to the sunlight is reduced, the sunlight absorption is increased, and the cell efficiency is improved. At the same time, the difference design of the average base angle of the fourth type of pyramid structure 101, the average base angle of the first type of pyramid structure 211, the average base angle of the second type of pyramid structure 311 and the average base angle of the third type of pyramid structure 411 can improve the utilization rate of sunlight, and the back surface of the cell has a lower back surface recombination loss, ensures the good passivation effect of the back surface, and realizes the optimization design of the cell.

[0094] Among them, the average base angle of the fourth type of pyramid structure 101 is any value in 50-85 °. For example, the average base angle of the fourth type of pyramid structure 101 can be any value in 50 °, 52 °, 54 °, 55 °, 56 °, 58 °, 60 °, 61 °, 62 °, 63 °, 64 °, 65 °, 66 °, 67 °, 68 °, 69 °, 70 °, 72 °, 73 °, 75 °, 85 °.

[0095] Please refer to Figures 10-12 As an embodiment of the utility model, the top of the first type of pyramid structure 211 is provided with a first circular arc surface 212, and / or the top of the second type of pyramid structure 311 is provided with a second circular arc surface 312.

[0096] In the embodiment, the top of the first type of pyramid structure 211 of the P-type doped region 2 is provided with a first circular arc surface 212, and the top of the second type of pyramid structure 311 of the N-type doped region 3 is provided with a second circular arc surface 312, that is, the top of the first type of pyramid structure 211 and the top of the second type of pyramid structure 311 are both smooth circular arc surfaces, which can reduce the surface recombination loss caused by the texturing of the P-type doped region 2 and the N-type doped region 3, and facilitate the deposition of the back surface film layer of the P-type doped region 2 and the N-type doped region 3, and improve the passivation performance of the back surface film layer of the P-type doped region 2 and the N-type doped region 3.

[0097] As an embodiment of the utility model, the curvature of the first circular arc surface 212 is smaller than the curvature of the second circular arc surface 312.

[0098] In the embodiment, the curvature of the first circular arc surface 212 is smaller than the curvature of the second circular arc surface 312, that is, the radius of the first circular arc surface 212 is larger than the radius of the second circular arc surface 312, and the top of the first type of pyramid structure 211 of the P-type doped region 2 is flatter than the top of the second type of pyramid structure 311 of the N-type doped region 3, which is more conducive to improving the passivation effect of the P-type doped region 2 and improving the cell efficiency.

[0099] As an embodiment of the utility model, the connecting place of two adjacent first type pyramid structures 211 is set as a third arc surface 213, and / or, the connecting place of two adjacent second type pyramid structures 311 is set as a fourth arc surface 313.

[0100] In the embodiment, the connecting place of the adjacent first type pyramid structure 211 of the P type doped area 2 and the connecting place of the adjacent second type pyramid structure 311 of the N type doped area 3 are set as arc surfaces under the condition that the P type doped area 2 and the N type doped area 3 are provided with a textured surface, so that the surface recombination loss caused by texturing of the P type doped area 2 and the N type doped area 3 can be further reduced, and the deposition of the back film layer of the P type doped area 2 and the N type doped area 3 is facilitated, so that the passivation performance of the back passivation layer of the P type doped area 2 and the N type doped area 3 can be improved.

[0101] As an embodiment of the utility model, the curvature of the third arc surface 213 is smaller than the curvature of the fourth arc surface 313.

[0102] In the embodiment, the curvature of the third arc surface 213 is smaller than the curvature of the fourth arc surface 313 under the condition that the P type doped area 2 and the N type doped area 3 are provided with a textured surface, that is, the radius of the third arc surface 213 is larger than the radius of the fourth arc surface 313, and the connecting place of the adjacent first type pyramid structure 211 of the P type doped area 2 is flatter than the connecting place of the adjacent second type pyramid structure 311 of the N type doped area 3, so that the passivation effect of the P type doped area 2 can be further improved, and the battery efficiency can be improved.

[0103] As an embodiment of the utility model, the top of the third type pyramid structure 411 is set as sharp, and the connecting place of two adjacent third type pyramid structures 411 is set as sharp.

[0104] In the embodiment, the top of the third type pyramid structure 411 in the isolation area 4 is set as sharp under the condition that the isolation area 4 is provided with a textured surface, and the connecting place of the adjacent third type pyramid structure 411 is also set as sharp, so that the optical performance of the isolation area 4 is better than the optical performance of the P type doped area 2 and the N type doped area 3, the good optical performance of the isolation area 4 is ensured, the good optical performance of the isolation area 4 and the good passivation performance of the P type doped area 2 and the N type doped area 3 are matched, and the battery efficiency can be further improved.

[0105] As an embodiment of the utility model, the height of the first type pyramid structure 211 is smaller than the height of the second type pyramid structure 311.

[0106] The height of the first type of pyramid structure 211 is the distance from the bottom surface of the first type of pyramid structure 211 to the top end thereof, and the height of the second type of pyramid structure 311 is the distance from the bottom surface of the second type of pyramid structure 311 to the top end thereof. In the case that the P-type doped region 2 and the N-type doped region 3 are provided with a textured surface, the textured surface of the P-type doped region 2 can be made more flat than the textured surface of the N-type doped region 3 due to the height of the first type of pyramid structure 211 being less than the height of the second type of pyramid structure 311, and the passivation performance of the P-type doped region 2 can be improved.

[0107] As an embodiment of the present application, the height of the second type of pyramid structure 311 is less than the height of the third type of pyramid structure 411.

[0108] In the embodiment, the height of the third type of pyramid structure 411 is the distance from the bottom surface of the third type of pyramid structure 411 to the top end thereof. In the case that the N-type doped region 3 and the isolation region 4 are provided with a textured surface, the passivation performance of the N-type doped region 3 can be improved due to the height of the second type of pyramid structure 311 being less than the height of the third type of pyramid structure 411, the passivation performance of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 decreases in turn, the optical performance of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 increases in turn, the optical performance and the passivation performance of the P-type doped region 2, the N-type doped region 3 and the isolation region 4 are well matched, and the battery efficiency can be further improved.

[0109] As an embodiment of the present application, the roughness of the side surface of the first type of pyramid structure 211 is less than the roughness of the side surface of the second type of pyramid structure 311.

[0110] In the case that the P-type doped region 2 and the N-type doped region 3 are provided with a textured surface, the roughness of the side surface of the first type of pyramid structure 211 is less than the roughness of the side surface of the second type of pyramid structure 311, that is, the fluctuation degree of the side surface of the first type of pyramid structure 211 is less than the fluctuation degree of the side surface of the second type of pyramid structure 311, the light reflection effect of the N-type doped region 3 can be improved, the optical performance of the N-type doped region 3 can be improved, the surface recombination loss of the P-type doped region 2 can be reduced, the passivation effect of the P-type doped region 2 can be improved, and the optical performance and the passivation effect of the P-type doped region 2 and the N-type doped region 3 can be balanced.

[0111] As an embodiment of the present application, the roughness of the side surface of the second type of pyramid structure 311 is less than the roughness of the side surface of the third type of pyramid structure 411.

[0112] In the embodiment, the roughness of the side surface of the second type of pyramid structure 311 is smaller than the roughness of the side surface of the third type of pyramid structure 411 when the N-type doped region 3 and the isolation region 4 are provided with a textured surface, that is, the fluctuation degree of the side surface of the second type of pyramid structure 311 is smaller than the fluctuation degree of the side surface of the third type of pyramid structure 411, which can improve the light reflection effect of the N-type doped region 3, is conducive to improving the optical performance of the N-type doped region 3, and can reduce the surface recombination loss of the N-type doped region 3, improve the passivation effect of the N-type doped region 3, and be conducive to the balance of the optical performance and the passivation effect of the N-type doped region 3.

[0113] Please refer to Figure 1 As an embodiment of the present application, the back contact solar cell further comprises:

[0114] The P-type doped layer 5 is arranged on the P-type doped region 2.

[0115] The N-type doped layer 6 is arranged on the N-type doped region 3.

[0116] In the embodiment, the P-type doped layer 5 is one or a combination of P-type polysilicon, P-type microcrystalline silicon, P-type nanocrystalline silicon, and P-type amorphous silicon, and the N-type doped layer 6 is one or a combination of N-type polysilicon, N-type microcrystalline silicon, N-type nanocrystalline silicon, and N-type amorphous silicon.

[0117] As an embodiment of the present application, the back contact solar cell further comprises:

[0118] The first passivation layer 7 is arranged between the P-type doped layer 5 and the back surface of the silicon substrate 1.

[0119] The second passivation layer 8 is arranged between the N-type doped layer 6 and the back surface of the silicon substrate 1.

[0120] The first passivation layer 7 and the second passivation layer 8 can be a silicon oxide layer. The first passivation layer 7 and the second passivation layer 8 passivate the back surface of the silicon substrate 1, further improving the passivation effect of the P-type doped region 2 and the N-type doped region 3.

[0121] As an embodiment of the present application, the back contact solar cell further comprises:

[0122] The first electrode 15 is arranged on the side of the P-type doped layer 5 away from the silicon substrate 1, and the first electrode 15 is in contact with the P-type doped layer 5.

[0123] The second electrode 16 is arranged on the side of the N-type doped layer 4 away from the silicon substrate 1, and the second electrode 16 is in contact with the N-type doped layer 4.

[0124] As an embodiment of the utility model, the distribution density of the first type of pyramid structure 211 in the region corresponding to the first electrode 15 of the P type doped region 2 is greater than the distribution density of the first type of pyramid structure 211 in the region not corresponding to the first electrode 15 of the P type doped region 2, which is conducive to improving the bonding tensile force between the first electrode 15 and the battery piece; similarly, the distribution density of the second type of pyramid structure 311 in the region corresponding to the second electrode 16 of the N type doped region 3 is greater than the distribution density of the second type of pyramid structure 311 in the region not corresponding to the second electrode 16 of the N type doped region 3, which is conducive to improving the bonding tensile force between the second electrode 16 and the battery piece.

[0125] As an embodiment of the utility model, further comprising:

[0126] The back passivation layer 17 covers the P type doped layer 5, the N type doped layer 6 and the isolation region 4.

[0127] In the embodiment, the first electrode 15 contacts the P type doped layer 5 through the back passivation layer 17; and the second electrode 16 contacts the N type doped layer 4 through the back passivation layer 17. The back passivation layer 17 can further improve the passivation effect of the battery and improve the battery efficiency. The back passivation layer 17 is at least one of an aluminum oxide film layer, a silicon oxide film layer, a silicon nitride film layer, a silicon carbide film layer and a silicon oxynitride film layer, or a combination of multiple thereof, for example, in some embodiments, the back passivation layer 17 can include an aluminum oxide film layer and a silicon nitride film layer stacked in sequence, which is not limited in particular herein.

[0128] The utility model embodiment further provides a battery assembly, the battery assembly includes the back contact solar cell of above-mentioned embodiment. It needs to be explained that, the battery assembly has same or similar beneficial effects with the above-mentioned back contact solar cell, and the related places between the two can be mutually referred, in order to avoid repetition, here will not be repeated.

[0129] In the embodiment, the plurality of back contact solar cells in the battery assembly can be sequentially connected together to form a battery string, thereby realizing the series connection of the current, for example, the connection of the battery pieces can be realized by setting a welding strip (bus bar, interconnecting strip), a conductive back plate and the like.

[0130] It can be understood that, in such an embodiment, the battery assembly can further include a metal frame, a back plate, photovoltaic glass and a glue film. The glue film can be filled between the front and back surfaces of the back contact solar cell, the photovoltaic glass and the adjacent battery pieces, and can be a transparent glue with good light transmission performance and aging resistance, for example, the glue film can use EVA glue film or POE glue film, which can be selected according to actual conditions, and is not limited herein.

[0131] The photovoltaic glass can be covered on the adhesive film on the front surface of the back contact solar cell. The photovoltaic glass can be super white glass, which has high light transmittance, high transparency, and excellent physical, mechanical and optical properties. For example, the light transmittance of the super white glass can be more than 92%, which can protect the back contact solar cell without affecting the efficiency of the back contact solar cell as much as possible. At the same time, the adhesive film can bond the photovoltaic glass and the back contact solar cell together, and the presence of the adhesive film can seal and insulate the back contact solar cell and prevent water and moisture.

[0132] The back plate can be attached to the adhesive film on the back surface of the back contact solar cell. The back plate can protect and support the back contact solar cell, has reliable insulation, water resistance and aging resistance. The back plate can have multiple choices, which can be tempered glass, organic glass, aluminum alloy TPT composite adhesive film, etc. The specific setting can be made according to the specific situation, which is not limited here. The whole composed of the back plate, the back contact solar cell, the adhesive film and the photovoltaic glass can be arranged on the metal frame. The metal frame serves as the main external support structure of the entire back contact solar cell module, and can stably support and install the back contact solar cell module. For example, the metal frame can be used to install the back contact solar cell module at the desired installation position.

[0133] The utility model embodiment further provides a photovoltaic system, the photovoltaic system includes the battery module of above -mentioned embodiment. It needs to be explained that the photovoltaic system has same or similar beneficial effect with above -mentioned back contact solar cell, and the related place between both can be mutually referred to, in order to avoid repetition, this place does not repeat here.

[0134] In the embodiment, the photovoltaic system can be applied in photovoltaic power stations, such as ground power stations, roof power stations, water surface power stations, etc. It can also be applied in devices or apparatuses that use solar energy to generate electricity, such as user solar power sources, solar street lamps, solar cars, solar buildings, etc. Of course, it can be understood that the application scenarios of the photovoltaic system are not limited to this. That is to say, the photovoltaic system can be applied in all fields that need to use solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system can include a photovoltaic array, a current combiner and an inverter. The photovoltaic array can be an array combination of multiple back contact solar cell modules. For example, multiple back contact solar cell modules can form multiple photovoltaic arrays. The photovoltaic arrays are connected to the current combiner. The current combiner can combine the currents generated by the photovoltaic arrays. The combined current flows through the inverter to convert into alternating current required by the power grid, and then is connected to the power grid to realize solar power supply.

[0135] In the description of the specification, the description of the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" and the like means 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 utility model. In the specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0136] The above is only the preferred embodiment of the utility model, and is not used to limit the utility model, and any modification, equivalent replacement and improvement, etc. made within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A back contact solar cell, characterized by, The silicon substrate comprises opposite front and back surfaces, the back surface comprising a P-type doped region, an N-type doped region, and an isolation region between the P-type doped region and the N-type doped region, at least two of the P-type doped region, the N-type doped region, and the isolation region being provided with a texture; the P-type doped region is provided with a first texture comprising a plurality of first pyramidal structures, and / or the N-type doped region is provided with a second texture comprising a plurality of second pyramidal structures, and / or the isolation region is provided with a third texture comprising a plurality of third pyramidal structures. The average base angle of the first pyramidal structures is smaller than the average base angle of the second pyramidal structures, and / or the average base angle of the first pyramidal structures is smaller than the average base angle of the third pyramidal structures, and / or the average base angle of the second pyramidal structures is smaller than the average base angle of the third pyramidal structures.

2. The back contact solar cell of claim 1, wherein, The P-type doped region is provided with the first texture, the N-type doped region is provided with the second texture, and the isolation region is provided with a non-texture.

3. The back contact solar cell of claim 1, wherein, The P-type doped region is provided with the first texture, the isolation region is provided with the third texture, and the N-type doped region is provided with a non-texture.

4. The back contact solar cell of claim 1, wherein, The N-type doped region is provided with the second texture, the isolation region is provided with the third texture, and the P-type doped region is provided with a non-texture.

5. The back contact solar cell of claim 1, wherein, The P-type doped region is provided with the first texture, the N-type doped region is provided with the second texture, and the isolation region is provided with the third texture.

6. The back contact solar cell of claim 1, wherein, The difference between the average base angle of the second pyramidal structures and the average base angle of the first pyramidal structures is greater than 5°, and / or the difference between the average base angle of the third pyramidal structures and the average base angle of the second pyramidal structures is greater than 5°, and / or the difference between the average base angle of the third pyramidal structures and the average base angle of the first pyramidal structures is greater than 10°.

7. The back contact solar cell of claim 1 wherein, The average base angle of the first pyramidal structures is 10-60°, the average base angle of the second pyramidal structures is 20-70°, and the average base angle of the third pyramidal structures is 30-85°.

8. The back contact solar cell of claim 7, wherein, The average base angle of the first pyramidal structures is 15-45°, the average base angle of the second pyramidal structures is 20-55°, and the average base angle of the third pyramidal structures is 40-75°.

9. The back contact solar cell of claim 1 wherein, The top of the first pyramidal structures is provided with a first circular arc surface, and / or the top of the second pyramidal structures is provided with a second circular arc surface.

10. The back contact solar cell of claim 9, wherein, The curvature of the first circular arc surface is smaller than the curvature of the second circular arc surface.

11. The back contact solar cell of claim 1 wherein, The connection between adjacent two first pyramidal structures is provided with a third circular arc surface, and / or the connection between adjacent two second pyramidal structures is provided with a fourth circular arc surface.

12. The back contact solar cell of claim 11, wherein, The curvature of the third circular arc surface is smaller than the curvature of the fourth circular arc surface.

13. The back contact solar cell of claim 1 wherein, The top of the third pyramidal structures is provided with a sharp structure, and the connection between adjacent two third pyramidal structures is provided with a sharp structure.

14. The back contact solar cell of claim 1 wherein, The height of the first pyramidal structures is smaller than the height of the second pyramidal structures.

15. The back contact solar cell of claim 1 wherein, The height of the second pyramidal structures is smaller than the height of the third pyramidal structures.

16. The back contact solar cell of claim 1 wherein, The side surface of the first type of pyramid structure has a roughness less than the roughness of the side surface of the second type of pyramid structure.

17. The back contact solar cell of claim 1 wherein, The side surface of the second type of pyramid structure has a roughness less than the roughness of the side surface of the third type of pyramid structure.

18. The back contact solar cell of claim 1 wherein, The front side of the silicon substrate is provided with a fourth texturing.

19. A battery assembly characterized by, A back contact solar cell comprising a back contact solar cell as defined in any one of claims 1 to 18.

20. A photovoltaic system characterized by, A solar module comprising a solar module as defined in claim 19.

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