A back-contact battery, battery module and photovoltaic system

Abstract

This invention relates to the field of photovoltaic technology and provides a back-contact battery, battery module, and photovoltaic system. The back-contact battery includes: a battery body, comprising a front side and a back side disposed opposite to each other along its thickness direction, and a side surface connecting the front and back sides, the side surface including a cut surface and a non-cut surface; a plurality of spacers spaced apart on the front side, each spacer including an upper surface disposed away from the front side along the thickness direction of the battery body; a first passivation layer formed on the cut surface; and a second passivation layer extending from the first passivation layer and formed on the front side, the second passivation layer covering the edge region of the front side near the cut surface, and covering part of the spacers, the ratio of the thickness of the second passivation layer in the region of the front side without spacers to the thickness of the second passivation layer on the upper surface of the spacers being 1.6 to 12. The back-contact battery of this invention can simultaneously achieve good passivation effect and good light transmittance on the front side, thereby improving battery performance.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and in particular to a back-contact battery, battery module and photovoltaic system. Background Technology

[0002] A solar cell is a semiconductor device that converts solar energy into electrical energy. Under sunlight, a photocurrent is generated inside the solar cell, which outputs electrical energy through metal electrodes. In recent years, solar cell manufacturing technology has continuously advanced, production costs have decreased, and conversion efficiency has increased. Solar cell power generation has become increasingly widespread and is an important energy source for electricity supply. In the manufacturing process of back-contact cells, after the entire solar cell is fabricated, it is typically sliced ​​into multiple back-contact cells, such as two-slice, three-slice, four-slice, eight-slice, and sixteen-slice cells. Interconnecting these slices helps reduce power loss; however, the cutting surfaces created by slicing the cells introduce efficiency losses. To passivate and repair damage to the cut surfaces of the back-contact cells, a passivation layer is usually applied to the cut surfaces.

[0003] In related technologies, to prevent scratches on the back contact battery during the stacking process, a spacer is usually required on the front side of the back contact battery. When a passivation layer is formed on the cut surface of the back contact battery, the passivation layer on the cut surface will be deposited around the edge area of ​​the front side of the battery. This means that the passivation layer formed on the edge area of ​​the front side of the battery will cover part of the spacer. The passivation layer stacked on the spacer will affect the light transmittance at the spacer location, thus affecting the overall light transmittance of the front side. For example, patent document CN120456666A discloses "forming an inorganic passivation layer on the cut surface, the inorganic passivation layer including an extension portion extending to the edge area of ​​the first side and / or the edge area of ​​the second side, the first side is provided with multiple spacers, and the extension portion at least partially covers at least one of the multiple spacers." However, this patent document does not optimize the thickness of the extension portion of the inorganic passivation layer at the spacer location and the thickness at the location where no spacer is provided. It is difficult to simultaneously ensure the passivation effect of the passivation layer at the edge of the front side of the battery and the light transmittance effect at the spacer location, thus presenting a problem of difficulty in simultaneously achieving a good passivation effect and good light transmittance on the front side. Summary of the Invention

[0004] This invention provides a back-contact battery, which aims to solve the problem that existing back-contact batteries cannot simultaneously achieve good passivation effect and good light transmittance on the front side.

[0005] This invention is implemented by providing a back contact battery, comprising: A battery body, the battery body including a front side and a back side disposed opposite to each other along its thickness direction, and a side surface connecting the front side and the back side, the side surface including a cut surface and a non-cut surface; A plurality of spacers are spaced apart on the front side, the spacers including an upper surface disposed away from the front side along the thickness direction of the battery body; The first passivation layer formed on the cut surface; and A second passivation layer extends from the first passivation layer and is formed on the front side. The second passivation layer covers the edge region of the front side near the cut surface. The second passivation layer covers a portion of the isolator. The ratio of the thickness of the second passivation layer in the area of ​​the front side where the isolator is not provided to the thickness of the second passivation layer on the upper surface of the isolator is 1.6 to 12. Preferably, the separator includes a side surface connecting the upper surface and the front surface, wherein the thickness of the second passivation layer on the side surface is greater than the thickness of the second passivation layer on the upper surface.

[0006] Preferably, the thickness of the second passivation layer in the area on the front side where the isolation element is not disposed is less than the thickness of the second passivation layer in the side side.

[0007] Preferably, the thickness of the second passivation layer in the area on the front side where the isolation element is not disposed is 25-60 nanometers.

[0008] Preferably, the thickness of the second passivation layer on the upper surface is 5-15 nanometers.

[0009] Preferably, the thickness of the second passivation layer on the side is 30-80 nanometers.

[0010] Preferred options also include: A third passivation layer formed on the non-cut surface; and A fourth passivation layer extends from the third passivation layer and is formed on the front side, the fourth passivation layer covering the edge region of the front side near the non-cut surface, and the fourth passivation layer covering a portion of the separator.

[0011] Preferably, the thickness of the fourth passivation layer in the area on the front side where the isolation element is not provided is less than the thickness of the second passivation layer in the area on the front side where the isolation element is not provided.

[0012] Preferably, the thickness of the fourth passivation layer on the upper surface of the separator is less than the thickness of the second passivation layer on the upper surface of the separator.

[0013] Preferably, the ratio of the sum of the areas of the isolator covered by the second passivation layer and the fourth passivation layer to the sum of the areas of the isolator not covered by the second passivation layer and the fourth passivation layer is 5% to 10%.

[0014] Preferably, the direction perpendicular to the cut surface is the first direction, the second passivation layer extends along the first direction from the edge of the cut surface to the center of the front surface, and the width of the second passivation layer along the first direction is 2~6mm.

[0015] Preferred options also include: A silicon oxide film is disposed between the first passivation layer and the cut surface.

[0016] Preferably, the thickness of the first passivation layer is greater than the thickness of the silicon oxide film.

[0017] Preferably, the thickness of the silicon oxide film is 0.5~5nm.

[0018] Preferably, the thickness of the silicon oxide film is 0.5~1.6 nm.

[0019] Preferably, the first passivation layer and the second passivation layer are one or at least two combinations of aluminum oxide layer, gallium oxide layer, silicon oxynitride layer, intrinsic amorphous silicon layer, and intrinsic polycrystalline silicon layer.

[0020] Preferably, the thickness of the first passivation layer is 10~200nm.

[0021] Preferably, the thickness of the first passivation layer is 10~80nm.

[0022] Preferably, the back contact battery further includes: A fifth passivation layer extends from the first passivation layer and is formed on the back side, the fifth passivation layer covering the edge region of the back side near the cut surface.

[0023] Preferably, the back contact battery further includes: A sixth passivation layer extends from the third passivation layer and is formed on the back side, the sixth passivation layer covering the edge region of the back side near the non-cut surface.

[0024] Preferred options also include: The metal electrode is disposed on the back side, and the thickness of the insulating member is greater than the thickness of the metal electrode.

[0025] The present invention also provides a battery assembly including the aforementioned back contact battery.

[0026] The present invention also provides a photovoltaic system including the above-described battery module.

[0027] This invention provides a back-contact battery by setting multiple spacers on the front side of the battery body, spaced apart, to protect the front side of the back-contact battery and prevent scratches during stacking. A first passivation layer is formed on a cut surface to passivate and repair damage to the cut surface. The first passivation layer extends to the front side to form a second passivation layer, covering the edge area of ​​the front side near the cut surface, to passivate and repair damage to the edge area of ​​the front side near the cut surface. Simultaneously, the ratio of the thickness of the second passivation layer in the area of ​​the front side without spacers to the thickness of the second passivation layer on the upper surface of the spacers is controlled to be 1.6~12, with the thicknesses within this ratio range. In other words, increasing the thickness of the second passivation layer in the area on the front without an isolator enhances its passivation and repair effect on the edge area near the cut surface, ensuring a good passivation effect for the area without an isolator near the cut surface. Simultaneously, reducing the thickness of the second passivation layer on the upper surface of the isolator reduces its shading effect, allowing sunlight to enter the battery body from the upper surface of the isolator. This ensures good absorption of sunlight by the back contact battery, achieving good photoelectric conversion efficiency. Thus, a balance is achieved between front passivation and front light transmission, resulting in both good front passivation and good front light transmittance, thereby improving battery efficiency.

[0028] In addition, the second passivation layer protects the covered separator and also protects the area on the front without a separator, thus improving the front wear resistance. The ratio of the thickness of the second passivation layer in the area on the front without a separator to the thickness of the second passivation layer on the upper surface of the separator is controlled to be 1.6~12. That is, increasing the thickness of the second passivation layer in the area on the front without a separator improves the wear resistance of the second passivation layer in this area. Within this ratio range, the second passivation layer can ensure good protection of the covered separator, better protect the front of the battery in back contact, and avoid excessive blocking and reflection of sunlight due to an excessively thick second passivation layer, further improving battery performance. Attached Figure Description

[0029] Figure 1 This is a three-dimensional schematic diagram of the back contact battery according to an embodiment of the present invention; Figure 2 This is a three-dimensional schematic diagram of a portion of the back contact battery structure according to an embodiment of the present invention; Figure 3 This is a front view of the back contact battery according to an embodiment of the present invention; Figure 4 For along Figure 3 A cross-sectional view along the AA direction; Figure 5 For along Figure 4 A magnified schematic diagram of part B in the middle; Figure 6 For along Figure 4 A magnified schematic diagram of part C in the middle; Figure 7 For along Figure 3 A cross-sectional schematic diagram of another embodiment in the AA direction.

[0030] Explanation of key symbols: The battery has a back contact battery 100, a battery body 1, a front side 11, a back side 12, a cut surface 131, a non-cut surface 132, a first passivation layer 31, a second passivation layer 32, a third passivation layer 33, a fourth passivation layer 34, a fifth passivation layer 35, a sixth passivation layer 36, a separator 21, an upper surface 211, a side surface 212, a silicon oxide film 37, and a metal electrode 6. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the invention, and should not be construed as limiting the invention. Furthermore, it should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0032] In the description of this invention, it should be understood that the terms "upper", "lower", "backlight", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0034] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0035] Please refer to Figures 1-5 An embodiment of the present invention provides a back contact battery 100, comprising: The battery body 1 includes a front side 11 and a back side 12 disposed opposite to each other along its thickness direction, and a side surface connecting the front side 11 and the back side 12. The side surface includes a cut surface 131 and a non-cut surface 132. A plurality of spacers 21 are spaced apart on the front side 11, each spacer 21 including an upper surface 211 disposed away from the front side 11 along the thickness direction of the battery body 1; and The first passivation layer 31 is formed on the cut surface 131; A second passivation layer 32 extends from the first passivation layer 31 and is formed on the front side 11. The second passivation layer 32 covers the edge area of ​​the front side 11 near the cut surface 131 and partially covers the isolation member 21. The ratio of the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 where the isolation member 21 is not provided to the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21 is 1.6 to 12.

[0036] In this embodiment of the invention, in the front side 11 and back side 12 of the battery body 1, the front side 11 is the light-facing surface of the back contact battery 100, and the back side 12 is the back-light-receiving surface of the back contact battery 100. The light-facing surface is the surface that mainly receives light when the back contact battery 100 is working. The side surface connects the front side 11 and the back side 12 of the back contact battery 100. The cut surface 131 refers to the newly generated surface during the process of cutting the back contact battery 100 from a whole solar cell, and the non-cut surface 132 is the original side surface of the whole back contact battery 100, that is, the non-cut surface 132 is the side surface excluding the cut surface 131. Among them, the side surface of the back contact battery 100 shown in the figure includes one cut surface 131 and three non-cut surfaces 132.

[0037] In this embodiment of the invention, the back contact battery 100 can be divided into two, three, or four sections, etc., and the specific sectioning form of the battery is not limited. The separator 21 of the back contact battery 100 is disposed on the front side 11 of the back contact battery 100. The separator 21 is used to protect the front side 11 of the back contact battery 100 and prevent possible damage to the front side 11 during transfer. For example, during the stacking of back contact batteries 100, the front side 11 of one back contact battery 100 contacts the back side 12 of another back contact battery 100. Due to the presence of the separator 21, the structure of the back side 12 of one back contact battery 100 can be prevented from scratching the front side 11 of the other back contact battery 100.

[0038] In this embodiment of the invention, the battery body 1 has a conventional structure for a back-contact battery. For example, the battery body 1 mainly includes a silicon substrate, a first doped layer and a second doped layer located on the back side of the silicon substrate with opposite doping types; wherein, one of the first doped layer and the second doped layer is an N-type doped layer and the other is a P-type doped layer; the P-type doped layer may contain one or more elements from Group IIIA of the periodic table (e.g., boron), and the N-type doped layer may contain one or more elements from Group VA of the periodic table (e.g., phosphorus). The first doped layer and the second doped layer are respectively connected to corresponding metal electrodes 6.

[0039] In this embodiment of the invention, the specific number of isolation members 21 is not limited. Multiple isolation members 21 can be arranged at equal intervals or at non-equal intervals. Multiple isolation members 21 are arranged at intervals on the front side 11, so that the isolation members 21 do not completely cover the front side 11. This can reduce the shading area of ​​the isolation members 21 on the front side 11, reduce the influence of the isolation members 21 on the sunlight incident on the front side 11, and make it more convenient for sunlight to enter the battery body 1 from the front side 11.

[0040] In this embodiment of the invention, the material of the separator 21 is not limited. For example, the separator 21 can be a UV adhesive (ultraviolet curable adhesive, also known as shadowless adhesive or photosensitive adhesive). The main components of UV adhesive include photoinitiators, thickeners, additives, monomers, and solvents. It initiates a cross-linking reaction through ultraviolet irradiation to form a solid structure, and has advantages such as fast curing speed, high bonding strength, and environmental friendliness without solvents. For example, UV adhesive is composed of oligomers, reactive diluents, photoinitiators, and other additives. Oligomers are the main component of UV adhesive, and their structure and molecular weight determine the final performance of UV adhesive, such as light curing rate, bonding performance, transparency, resistance, hardness, and flexibility. Commonly used oligomers in UV adhesives include polyurethane acrylates, epoxy acrylates, pure acrylates, polyester acrylates, and polyether acrylates. In addition, some new oligomers can also be used in UV adhesives, such as hyperbranched oligomers and free radical cationic hybrid oligomers. The specific composition of UV adhesive is not limited.

[0041] In this embodiment of the invention, the edge region of the front surface 11 covered by the second passivation layer 32 near the cut surface 131 includes a region with a spacer 21 and a region without a spacer 21. The region without a spacer 21 is the region of the front surface 11 that does not have a spacer 21. The region of the front surface 11 without a spacer 21 includes the region between the edge of the cut surface 131 and the spacer 21, and the region between adjacent spacers 21.

[0042] An embodiment of the present invention provides a back contact battery 100 by providing multiple insulating members 21 on the front side 11 of the battery body 1. The multiple insulating members 21 are spaced apart on the front side 11 of the battery body 1. The multiple insulating members 21 protect the front side 11 of the back contact battery 100 and prevent scratches on the front side 11 during the stacking of the back contact batteries 100. Specifically, during the stacking of the back contact batteries 100, the front side 11 of one back contact battery 100 and the back side 12 of another back contact battery 100 come into contact. Due to the presence of the insulating members 21, the structure of the back side 12 of one back contact battery 100 can be prevented from scratching the front side 11 of the other back contact battery 100.

[0043] An embodiment of the present invention provides a back contact battery 100 in which a first passivation layer 31 is formed on a cut surface 131. The first passivation layer 31 is used to achieve passivation repair of damage to the cut surface 131. The first passivation layer 31 extends to the front surface 11 to form a second passivation layer 32. The second passivation layer 32 covers the edge region of the front surface 11 near the cut surface 131, thereby achieving passivation repair of damage to the edge region of the front surface 11 near the cut surface 131. Therefore, the second passivation layer 32 can improve the passivation effect of the edge region of the front surface 11 near the cut surface 131. At the same time, the second passivation layer 32 is controlled to be located on the front surface 11. The ratio of the thickness D1 of the area of ​​the front surface 11 without the isolation member 21 to the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21 is 1.6 to 12. The thicknesses of the two are within this ratio range. That is, the thickness D1 of the second passivation layer 32 on the front surface 11 without the isolation member 21 is greater than the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21, and the thickness D1 of the second passivation layer 32 on the front surface 11 without the isolation member 21 is 1.6 to 12 of the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21.

[0044] In this embodiment of the invention, the ratio of thickness D1 to thickness D2 is controlled within the range of 1.6 to 12. This increases the thickness of the second passivation layer 32 in the area of ​​the front surface 11 without the isolation member 21, enhancing the damage repair capability of the second passivation layer 32 in this area. This allows the second passivation layer 32 to effectively passivate the area of ​​the front surface 11 near the edge of the cut surface 131 without the isolation member 21, achieving good damage repair in this area. Furthermore, reducing the thickness of the second passivation layer 32 in the area of ​​the isolation member 21... The thickness design of the upper surface 211 can reduce the obstruction and reflection of sunlight by the second passivation layer 32. Therefore, it is beneficial to reduce the shading effect of the second passivation layer 32 on the upper surface 211 of the separator 2, and facilitate the entry of sunlight from the upper surface 211 of the separator 21 into the battery body 1, ensuring a good absorption rate of sunlight by the back contact battery 100 and achieving a good photoelectric conversion efficiency of the back contact battery 100. Therefore, by controlling the ratio of thickness D1 to thickness D2 within the range of 1.6 to 12, a good passivation effect and a good light transmittance of the front surface 11 can be achieved at the same time.

[0045] Furthermore, the second passivation layer 32 protects the separator 21 in the edge region of the front side 11 near the cut surface 131, and also protects the area of ​​the front side 11 without the separator 21. This improves the wear resistance of the front side 11 and prevents the separator 21 covered by the second passivation layer 32 from yellowing under long-term sunlight. The ratio of the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 without the separator 21 to the thickness D2 of the second passivation layer 32 on the upper surface 211 of the separator 21 is controlled to be 1.6~12. That is, increasing the thickness of the second passivation layer 32 in the area of ​​the front side 11 without the separator 21 improves the wear resistance of the second passivation layer 32 in this area, better protects the front side 11 of the back contact battery, and avoids excessive blocking and reflection of sunlight due to an excessively thick second passivation layer 32, further improving battery performance. Therefore, in this embodiment of the invention, the ratio of thickness D1 to thickness D2 is set in the range of 1.6 to 12, which can achieve a balance of multiple effects and improve battery performance.

[0046] In this embodiment of the invention, the ratio of the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 where the isolation member 21 is not provided to the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21 can be any value from 1.6 to 12.

[0047] For example, the ratio of thickness D1 to thickness D2 can be any value among 1.6, 1.7, 1.8, 1.9, 2, 2.2, 3, 3.6, 4, 4.5, 5, 5.6, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, and 12.

[0048] In this document, the term "thickness" refers to "average thickness," which is the average thickness calculated from the thicknesses of multiple measurement points. For example, the thickness D1 of the second passivation layer 32 in the area of ​​the front surface 11 where the isolator 21 is not located is: the average thickness of the second passivation layer 32 in the area of ​​the front surface 11 where the isolator 21 is not located. Specifically, multiple measurement points can be selected on the surface of the second passivation layer 32 corresponding to the area where the isolator 21 is not located and which is far from the front surface 11, for example, 5 to 10 measurement points. The arithmetic mean of the vertical distances between these measurement points and the surface of the second passivation layer 32 near the front surface 11 is calculated to obtain the thickness D1 of the second passivation layer 32 in the area of ​​the front surface 11 where the isolator 21 is not located. Similarly, the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolator 21 is: the average thickness of the second passivation layer 32 on the upper surface 211 of the isolator 21. Specifically, 5 to 10 measurement points can be selected on the surface of the second passivation layer 32 away from the upper surface 211 of the separator 21. The arithmetic mean of the vertical distances between these measurement points and the surface of the second passivation layer 32 near the upper surface 211 of the separator 21 can be calculated to obtain the thickness D2 of the second passivation layer 32 on the upper surface 211 of the separator 21.

[0049] As an embodiment of the present invention, the isolation member 21 includes a side surface 212 connecting the upper surface 211 and the front surface 11, and the thickness D3 of the second passivation layer 32 on the side surface 212 is greater than the thickness D2 of the second passivation layer 32 on the upper surface 211.

[0050] In this embodiment, the thickness D3 of the second passivation layer 32 on the side 212 of the separator 21 is the average thickness of the second passivation layer 32 on the side 212 of the separator 21. Specifically, 5 to 10 measurement points can be selected on the surface of the second passivation layer 32 away from the side 212 of the separator 21, and the arithmetic mean of the vertical distances between these measurement points and the surface of the second passivation layer 32 near the side 212 of the separator 21 can be calculated to obtain the thickness D3 of the second passivation layer 32 on the side 212 of the separator 21.

[0051] As an embodiment of the present invention, the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 where the isolation member 21 is not provided is less than the thickness D3 of the second passivation layer 32 in the side side 212 of the isolation member 21.

[0052] In this embodiment, since an excessively thick second passivation layer 32 will cause a decrease in the solar energy absorption rate of the battery and affect the conversion efficiency, the thickness D1 of the second passivation layer 32 in the area of ​​the front surface 11 where the isolation member 21 is not provided is controlled to be less than the thickness D3 of the second passivation layer 32 on the side 212 of the isolation member 21. This can reduce the light transmission effect of the second passivation layer 32 on the area of ​​the front surface 11 where the isolation member 21 is not provided, avoid the second passivation layer 32 being too thick at the upper surface 211 position, thus affecting the solar energy absorption rate of the battery, and avoid the second passivation layer 32 being too thin at the side 212 position, thus better preventing the isolation member 21 from yellowing and discoloring.

[0053] As an embodiment of the present invention, the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 where the isolation member 21 is not provided is 25~60 nanometers.

[0054] In this embodiment, the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 without the isolation member 21 is controlled to be 25-60 nanometers. This effectively achieves the passivation effect in the area of ​​the front side without the isolation member 21, while ensuring good light transmittance in this area, allowing sunlight to pass through the second passivation layer 32 and enter the front side 11. The thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 without the isolation member 21 can be any value from 25 to 60 nanometers. For example, the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 without the isolation member 21 can be any value among 25 nanometers, 30 nanometers, 32 nanometers, 35 nanometers, 38 nanometers, 40 nanometers, 42 nanometers, 45 nanometers, 50 nanometers, 52 nanometers, 55 nanometers, and 60 nanometers.

[0055] As an embodiment of the present invention, the thickness D2 of the second passivation layer 32 on the upper surface 211 is 5~15 nanometers.

[0056] In this embodiment, the thickness D2 of the second passivation layer 32 on the upper surface 211 is controlled to be 5-15 nanometers. This ensures that sunlight can pass through the second passivation layer 32 to the upper surface 211 of the separator 21, reducing the shading effect of the second passivation layer 32 on the upper surface 211 of the separator 21. This facilitates sunlight entering the battery body 1 from the upper surface 211 of the separator 21. Furthermore, within this thickness range, the second passivation layer 32 provides good protection for the upper surface 211 of the separator 21, preventing scratches or wear and preventing yellowing or discoloration of the separator 21 under prolonged sunlight exposure. For example, the thickness D2 of the second passivation layer 32 on the upper surface 211 can be any value among 5 nanometers, 6 nanometers, 7 nanometers, 8 nanometers, 9 nanometers, 10 nanometers, 11 nanometers, 12 nanometers, 13 nanometers, 14 nanometers, and 15 nanometers.

[0057] As an embodiment of the present invention, the thickness D3 of the second passivation layer 32 on the side 212 is 30~80 nanometers.

[0058] In this embodiment, the thickness D3 of the second passivation layer 32 on the side 212 is controlled to be 30-80 nanometers. This effectively prevents the insulating component 21 from yellowing and discoloring under long-term sunlight exposure, while also ensuring that sunlight can pass through the second passivation layer 32 to the side 212. The thickness D3 of the second passivation layer 32 on the side 212 can be any value within the range of 30-80 nanometers. For example, the thickness D3 of the second passivation layer 32 on the side 212 can be any value among 30 nanometers, 35 nanometers, 40 nanometers, 42 nanometers, 45 nanometers, 50 nanometers, 53 nanometers, 58 nanometers, 60 nanometers, 64 nanometers, 70 nanometers, 72 nanometers, 76 nanometers, and 80 nanometers.

[0059] As an embodiment of the present invention, the second passivation layer 32 is made of the same material as the first passivation layer 31, and the second passivation layer 32 and the first passivation layer 31 are integrally formed, that is, the second passivation layer 32 and the first passivation layer 31 are deposited simultaneously.

[0060] As one embodiment of the present invention, it also includes: A third passivation layer 33 is formed on the non-cut surface 132; A fourth passivation layer 34 extends from the third passivation layer 33 and is formed on the front side 11. The fourth passivation layer 34 covers the edge region of the front side 11 near the non-cut surface 132 and covers part of the separator 21.

[0061] In this embodiment, a third passivation layer 33 is provided on the non-cut surface 132. The third passivation layer 33 passesivates the non-cut surface 132, which can reduce the recombination loss of the solar cell. The third passivation layer 33 can be made of the same material as the first passivation layer 31, or they can be different. Preferably, the third passivation layer 33 and the first passivation layer 31 are made of the same material, and the third passivation layer 33 and the first passivation layer 31 are integrally formed. That is, the third passivation layer 33 and the first passivation layer 31 can be deposited simultaneously, without the need to prepare the third passivation layer 33 and the first passivation layer 31 separately.

[0062] In this embodiment, the third passivation layer 33 extends to the edge region of the front surface 11 near the non-cut surface 132 to form a fourth passivation layer 34. The fourth passivation layer 34 passivates the edge region of the front surface 11 near the non-cut surface 132, which can further improve battery efficiency. The fourth passivation layer 34 and the third passivation layer 33 may be made of the same material or different materials. Preferably, the fourth passivation layer 34 and the third passivation layer 33 are made of the same material, and the fourth passivation layer 34 and the third passivation layer 33 are integrally formed, that is, the fourth passivation layer 34 and the third passivation layer 33 can be deposited simultaneously.

[0063] As an embodiment of the present invention, the thickness D4 of the fourth passivation layer 34 in the area of ​​the front side 11 where no isolation member 21 is provided is less than the thickness D1 of the second passivation layer 32 in the area of ​​the front side 11 where no isolation member 21 is provided.

[0064] In this embodiment, since the defect state density of the area without isolation member 21 in the edge region of the front surface 11 near the cut surface 131 is greater than that of the area without isolation member 21 in the edge region of the front surface 11 near the non-cut surface 132, the thickness D4 of the fourth passivation layer 34 in the area without isolation member 21 of the front surface 11 is controlled to be less than the thickness D1 of the second passivation layer 32 in the area without isolation member 21 of the front surface 11. On the one hand, making the thickness of the second passivation layer 32 in the area without isolation member 21 in the edge region of the front surface 11 near the cut surface 131 is greater, which is more conducive to improving the passivation effect of the second passivation layer 32. On the other hand, the thickness of the fourth passivation layer 34 in the area without isolation member 21 in the edge region of the front surface 11 near the non-cut surface 132 is smaller, which is conducive to reducing the obstruction and reflection of sunlight by the fourth passivation layer 34. As an embodiment of the present invention, the thickness D5 of the fourth passivation layer 34 on the upper surface 211 of the isolation member 21 is less than the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21.

[0065] In this embodiment, the thickness D5 of the fourth passivation layer 34 on the upper surface 211 of the isolation member 21 is controlled to be less than the thickness D2 of the second passivation layer 32 on the upper surface 211 of the isolation member 21. This makes the thickness of the fourth passivation layer 34 on the upper surface 211 of the isolation member 21 smaller, which helps to reduce the obstruction and reflection of sunlight by the fourth passivation layer 34, and at the same time can improve the reliability of the isolation member 21 covered by the second passivation layer 32 against yellowing and discoloration. As an embodiment of the present invention, the thickness D6 of the fourth passivation layer 34 on the side 212 of the isolation member 21 is less than the thickness D3 of the second passivation layer 32 on the side 212 of the isolation member 21.

[0066] In this embodiment, the thickness D6 of the fourth passivation layer 34 on the side 212 of the isolator 21 is controlled to be less than the thickness D3 of the second passivation layer 32 on the side 212 of the isolator 21, so that the thickness of the fourth passivation layer 34 on the side 212 of the isolator 21 is smaller, which helps to further reduce the obstruction and reflection of sunlight by the fourth passivation layer 34, and at the same time can further improve the reliability of the isolator 21 covered by the second passivation layer 32 against yellowing and discoloration. As an embodiment of the present invention, the ratio of the sum of the areas of the isolation member 21 covered by the second passivation layer 32 and the fourth passivation layer 34 to the sum of the areas of the isolation member 21 not covered by the second passivation layer 32 and the fourth passivation layer 34 is greater than 20% and less than 50%.

[0067] In this embodiment, the sum of the areas of the isolator 21 covered by the second passivation layer 32 and the fourth passivation layer 34 is, in other words, the total orthographic projection area of ​​the areas of the isolator 21 covered by the second passivation layer 32 and the fourth passivation layer 34 on the front surface 11; the area of ​​the isolator 21 not covered by the second passivation layer 32 and the fourth passivation layer 34 is, in other words, the total orthographic projection area of ​​the isolator 21 not covered by the second passivation layer 32 and the fourth passivation layer 34 on the front surface 11; the control isolator 21 is covered by the second passivation layer 32 and the fourth passivation layer 34. The ratio of the sum of the areas covered by the second passivation layer 32 and the fourth passivation layer 34 to the area of ​​the spacer 21 not covered by the second passivation layer 32 and the fourth passivation layer 34 is greater than 20% and less than 50%. This ensures that the second passivation layer 32 and the fourth passivation layer 34 can cover a sufficient area of ​​the spacer 21, effectively preventing discoloration and yellowing of the spacer 21 at the edge of the front 11, while also avoiding excessive coverage by the second passivation layer 32 and the fourth passivation layer 34, which would affect the light transmittance of the front 11.

[0068] As an embodiment of the present invention, the direction perpendicular to the cutting surface 131 is the first direction Y, the second passivation layer 32 extends along the first direction Y from the edge of the cutting surface 131 to the center of the front surface 11, and the width W1 of the second passivation layer 32 along the first direction Y is 2~6mm.

[0069] In this embodiment, the width W1 of the second passivation layer 32 along the first direction Y is the average distance along the first direction Y between the edge of the second passivation layer 32 near the cut surface 131 and the edge of the second passivation layer 32 near the center of the front surface 11. The edge of the second passivation layer 32 can be a straight line or an irregular shape, such as a wavy shape.

[0070] Specifically, multiple measurement points can be selected on the edge of the second passivation layer 32 near the center of the front surface 11, for example, 5 to 10 measurement points. The arithmetic mean of the vertical distances from these measurement points to the edge of the second passivation layer 32 near the cut surface 131 is calculated as the width W1 of the second passivation layer 32 along the first direction Y. By controlling the width W1 of the second passivation layer 32 along the first direction Y to be 2 to 6 mm, the width W1 of the second passivation layer 32 is avoided from being too large or too small. This can effectively achieve the edge passivation effect of the second passivation layer 32 on the front surface 11, and also prevent the overlap area between the second passivation layer 32 and the insulating member 21 from being too large, which would affect the solar transmittance of the front surface 11.

[0071] As an embodiment of the present invention, the thickness D7 of the first passivation layer 31 is greater than the thickness D8 of the third passivation layer 33.

[0072] In this embodiment, controlling the thickness D7 of the first passivation layer 31 to be greater than the thickness D8 of the third passivation layer 33 can further improve the passivation effect of the first passivation layer 31 on the cut surface 131. Of course, the thickness D7 of the first passivation layer 31 can also be the same as the thickness D8 of the third passivation layer 33.

[0073] As an embodiment of the present invention, the thickness D7 of the first passivation layer 31 is 10~200nm.

[0074] In this embodiment, the thickness of the first passivation layer 31 is controlled to be 10~200nm, which facilitates the processing of the first passivation layer 31 and ensures the passivation effect of the first passivation layer 31 on the cut surface 131.

[0075] As an embodiment of the present invention, the thickness of the first passivation layer 31 is 10~80nm.

[0076] In this embodiment, the thickness of the first passivation layer 31 is further controlled to be 10~80nm, which further facilitates the processing of the first passivation layer 31 and can ensure the passivation effect of the first passivation layer 31 on the cut surface 131.

[0077] As an embodiment of the present invention, the first passivation layer 31 is one or a combination of at least two of the following: aluminum oxide layer, gallium oxide layer, silicon oxynitride layer, intrinsic amorphous silicon layer, and intrinsic polycrystalline silicon layer.

[0078] In this embodiment, the first passivation layer 31 can be one of an aluminum oxide layer, a gallium oxide layer, a silicon oxynitride layer, an intrinsic amorphous silicon layer, and an intrinsic polycrystalline silicon layer, or it can be a stack of at least two of the aluminum oxide layer, gallium oxide layer, silicon oxynitride layer, intrinsic amorphous silicon layer, and intrinsic polycrystalline silicon layer. More preferably, the first passivation layer 31 is one of an aluminum oxide layer, a gallium oxide layer, and a silicon oxynitride layer, or a combination of at least two of them.

[0079] As an embodiment of the present invention, the second passivation layer 32 is one or a combination of at least two of the following: aluminum oxide layer, gallium oxide layer, silicon oxynitride layer, intrinsic amorphous silicon layer, and intrinsic polycrystalline silicon layer.

[0080] In this embodiment, the second passivation layer 32 can be one of an aluminum oxide layer, a gallium oxide layer, a silicon oxynitride layer, an intrinsic amorphous silicon layer, or an intrinsic polycrystalline silicon layer, or it can be a stacked structure of at least two of these layers. Preferably, both the first passivation layer 31 and the second passivation layer 32 are aluminum oxide layers, which facilitates the processing of the first passivation layer 31 and the second passivation layer 32. Furthermore, the third passivation layer 33 is also one of an aluminum oxide layer, a gallium oxide layer, a silicon oxynitride layer, an intrinsic amorphous silicon layer, or an intrinsic polycrystalline silicon layer, or a combination of at least two of these layers.

[0081] As an embodiment of the present invention, the first passivation layer 31 and the second passivation layer 32 are integrally formed structures.

[0082] In this embodiment, the first passivation layer 31 and the second passivation layer 32 are processed and formed simultaneously, which facilitates the processing of the first passivation layer 31 and the second passivation layer 32. Specifically, when the first passivation layer 31 is formed on the cutting surface 131, the first passivation layer 31 is plated around the front surface 11 to form the second passivation layer 32.

[0083] Please refer to this again. Figure 4 As an embodiment of the present invention, the back contact battery 100 further includes: A fifth passivation layer 35 extends from the first passivation layer 31 and is formed on the back surface 12, covering the edge region of the back surface 12 near the cut surface 131.

[0084] In this embodiment, the fifth passivation layer 35 can be used to repair damage in the edge region of the back surface 12 near the cut surface 131, reducing battery recombination losses and facilitating further improvement of battery efficiency. Preferably, the fifth passivation layer 35 is made of the same material as the first passivation layer 31. When forming the first passivation layer 31, the first passivation layer 31 is deposited around the back surface 12 to form the fifth passivation layer 35, eliminating the need for separate processing of the fifth passivation layer 35.

[0085] In this embodiment, the thickness of the fifth passivation layer 35 can be less than or equal to the thickness of the first passivation layer 31, which can reduce the reflection of sunlight incident on the back side 12 by the fifth passivation layer 35, thereby improving the utilization rate of sunlight. Preferably, the thickness of the fifth passivation layer 35 is less than the thickness of the first passivation layer 31, which can further reduce the reflection of sunlight incident on the back side 12 by the fifth passivation layer 35, thereby improving the utilization rate of sunlight.

[0086] As an embodiment of the present invention, the back contact battery 100 further includes: A sixth passivation layer 36 extends from the third passivation layer 33 and is formed on the back surface 12, covering the edge region of the back surface 12 near the non-cut surface 132.

[0087] In this embodiment, the sixth passivation layer 36 can be used to passivate the edge region of the back surface 12 near the non-cut surface 132, which is beneficial to further improve battery efficiency. Preferably, the sixth passivation layer 36 is made of the same material as the third passivation layer 33. When forming the third passivation layer 33, the third passivation layer 33 is deposited around the back surface 12 to form the sixth passivation layer 36, eliminating the need for separate processing of the sixth passivation layer 36. Preferably, the thickness of the sixth passivation layer 36 is less than the thickness of the third passivation layer 33, which can further reduce the absorption or reflection of sunlight incident on the back surface 12 by the sixth passivation layer 36, thereby improving the utilization rate of sunlight.

[0088] Please refer to Figure 6 As one embodiment of the present invention, it further includes: A silicon oxide film 37 is disposed between the first passivation layer 31 and the cut surface 131.

[0089] In this embodiment, a silicon oxide film 37 is formed between the first passivation layer 31 and the cutting surface 131. The silicon oxide film 37 can further enhance the passivation effect of the cutting surface 131, allowing the cutting surface 131 to achieve passivation through the combined action of the first passivation layer 31 and the silicon oxide film 37. In this embodiment, the silicon oxide film 37 can be directly formed by thermal oxidation of the cutting surface 131, which is convenient for processing; moreover, the silicon oxide film 37 can achieve a good passivation effect on the cutting surface 131.

[0090] As an embodiment of the present invention, the thickness of the first passivation layer 31 is greater than the thickness of the silicon oxide film 37, which facilitates the processing of the silicon oxide film 37. Only thermal oxidation treatment of the cut surface 131 is required to generate the silicon oxide film 37.

[0091] As an embodiment of the present invention, the thickness of the silicon oxide film 37 is 0.5~5nm.

[0092] In this embodiment, the thickness of the silicon oxide film 37 is controlled to be 0.5~5nm, which further facilitates the processing of the silicon oxide film 37 and enables the silicon oxide film 37 to achieve a good passivation effect on the cut surface 131.

[0093] As an embodiment of the present invention, the thickness of the silicon oxide film 37 is 0.5~1.6 nm.

[0094] In this embodiment, the thickness of the silicon oxide film 37 is further controlled to be 0.5~1.6nm, which further facilitates the processing of the silicon oxide film 37 and enables the silicon oxide film 37 to achieve a good passivation effect on the cut surface 131.

[0095] Please refer to this again. Figure 4 As one embodiment of the present invention, it further includes: The metal electrode 6 is located on the back side 12, and the thickness H1 of the insulating member 21 is greater than the thickness H2 of the metal electrode 6.

[0096] In this embodiment, the metal electrode 6 specifically includes a positive metal electrode and a negative metal electrode. During the stacking of multiple back-contact batteries 100, the front side 11 of one back-contact battery 100 contacts the back side 12 of another back-contact battery 100. During normal stacking, the spacer 21 on the front side 11 of one back-contact battery 100 contacts the metal electrode 6 on the back side 12 of another back-contact battery 100, preventing the metal electrode 6 on the back side 12 of one back-contact battery 100 from scratching the front side 11 of the other back-contact battery 100. However, during stacking, if the spacer 21 on the front side 11 of one back contact battery 100 and the metal electrode 6 on the back side 12 of another back contact battery 100 are misaligned, the metal electrode 6 on the back side 12 of the other back contact battery 100 will contact the area on the front side 11 of the back contact battery 100 where the spacer 21 is not located. If the thickness H1 of the spacer 21 is less than the thickness H2 of the metal electrode 6, the metal electrode 6 will directly contact the front side 11 of the back contact battery 100, easily scratching it. Therefore, in this embodiment, the thickness H1 of the spacer 21 is controlled to be greater than the thickness H2 of the metal electrode 6. During the stacking production process of the back contact batteries 100, even if the spacer 21 on the front side 11 of one back contact battery 100 and the metal electrode 6 on the back side 12 of another back contact battery 100 are misaligned, the metal electrode 6 can be prevented from scratching the front side 11 of the back contact battery 100, thereby improving the reliability of the spacer 21 in protecting the front side 11.

[0097] This invention also provides a battery assembly, which includes the back contact battery 100 described in the above embodiments. It should be noted that this battery assembly has the same or similar beneficial effects as the back contact battery 100, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0098] In this embodiment, multiple back-contact batteries 100 in the battery assembly are connected in series by solder strips to form a battery string, thereby achieving series current collection and output.

[0099] It is understood that in such embodiments, the battery assembly may also include a metal frame, a backsheet, photovoltaic glass, and an encapsulating film. The encapsulating film may be filled between the front and back sides of the back contact battery 100, the photovoltaic glass, adjacent battery cells, etc. As a filler, it may be a transparent colloid with good light transmittance and aging resistance. For example, the encapsulating film may be an EVA film or a POE film, and the specific choice can be made according to the actual situation, without limitation.

[0100] Photovoltaic glass can be applied to the encapsulating film on the front side of the back contact cell 100. The photovoltaic glass can be ultra-clear glass, which has high light transmittance, high transparency, and superior physical, mechanical, and optical properties. For example, ultra-clear glass can achieve a light transmittance of over 92%. It can protect the back contact cell 100 while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back contact cell 100 together, providing sealing, insulation, and waterproofing / moisture protection for the back contact cell 100.

[0101] The backsheet can be attached to the adhesive film on the back side of the back contact cell 100. The backsheet provides protection and support for the back contact cell 100, and offers reliable insulation, water resistance, and aging resistance. Multiple options are available for the backsheet, typically tempered glass, acrylic glass, or aluminum alloy TPT composite adhesive film, etc., and the specific choice is determined based on the specific circumstances and is not limited here. The backsheet, back contact cell 100, adhesive film, and photovoltaic glass can be mounted on a metal frame. The metal frame serves as the main external support structure for the entire battery module, providing stable support and installation. For example, the battery module can be installed at the desired location using the metal frame.

[0102] This invention also provides a photovoltaic system, which includes the battery module described in the above embodiments. It should be noted that this photovoltaic system has the same or similar beneficial effects as the back-contact battery 100 described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0103] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.

[0104] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0105] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A back-contact battery, characterized in that, include: A battery body, the battery body including a front side and a back side disposed opposite to each other along its thickness direction, and a side surface connecting the front side and the back side, the side surface including a cut surface and a non-cut surface; A plurality of spacers are spaced apart on the front side, the spacers including an upper surface disposed away from the front side along the thickness direction of the battery body; The first passivation layer formed on the cut surface; and A second passivation layer extends from the first passivation layer and is formed on the front side. The second passivation layer covers the edge region of the front side near the cut surface. The second passivation layer covers a portion of the isolator. The ratio of the thickness of the second passivation layer in the area of ​​the front side where the isolator is not provided to the thickness of the second passivation layer on the upper surface of the isolator is 1.6 to 12.

2. The back contact battery according to claim 1, characterized in that, The isolation element includes a side surface connecting the upper surface and the front surface, wherein the thickness of the second passivation layer on the side surface is greater than the thickness of the second passivation layer on the upper surface.

3. The back contact battery according to claim 2, characterized in that, The thickness of the second passivation layer in the area on the front side where the isolation element is not located is less than the thickness of the second passivation layer in the side side.

4. The back contact battery according to claim 1, characterized in that, The second passivation layer has a thickness of 25-60 nanometers in the area on the front side where the isolation element is not located.

5. The back contact battery according to claim 1, characterized in that, The second passivation layer on the upper surface has a thickness of 5-15 nanometers.

6. The back contact battery according to claim 2, characterized in that, The second passivation layer has a thickness of 30-80 nanometers on the side surface.

7. The back contact battery according to claim 1, characterized in that, Also includes: A third passivation layer is formed on the non-cut surface; and A fourth passivation layer extends from the third passivation layer and is formed on the front side, the fourth passivation layer covering the edge region of the front side near the non-cut surface, and the fourth passivation layer covering a portion of the separator.

8. The back contact battery according to claim 7, characterized in that, The thickness of the fourth passivation layer in the area on the front side where the isolation element is not located is less than the thickness of the second passivation layer in the area on the front side where the isolation element is not located.

9. The back contact battery according to claim 7, characterized in that, The thickness of the fourth passivation layer on the upper surface of the isolator is less than the thickness of the second passivation layer on the upper surface of the isolator.

10. The back contact battery according to claim 7, characterized in that, The ratio of the sum of the areas of the isolator covered by the second passivation layer and the fourth passivation layer to the sum of the areas of the isolator not covered by the second passivation layer and the fourth passivation layer is 5% to 10%.

11. The back contact battery according to claim 1, characterized in that, The direction perpendicular to the cut surface is the first direction, the second passivation layer extends along the first direction from the edge of the cut surface to the center of the front surface, and the width of the second passivation layer along the first direction is 2~6mm.

12. The back contact battery according to claim 1, characterized in that, Also includes: A silicon oxide film is disposed between the first passivation layer and the cut surface.

13. The back contact battery according to claim 12, characterized in that, The thickness of the first passivation layer is greater than the thickness of the silicon oxide film.

14. The back contact battery according to claim 12, characterized in that, The thickness of the silicon oxide film is 0.5~5nm.

15. The back contact battery according to claim 14, characterized in that, The thickness of the silicon oxide film is 0.5~1.6 nm.

16. The back contact battery according to claim 1, characterized in that, The first passivation layer and the second passivation layer are respectively one or at least two combinations of aluminum oxide layer, gallium oxide layer, silicon oxynitride layer, intrinsic amorphous silicon layer, and intrinsic polycrystalline silicon layer.

17. The back contact battery according to claim 1, characterized in that, The thickness of the first passivation layer is 10~200nm.

18. The back contact battery according to claim 17, characterized in that, The thickness of the first passivation layer is 10~80nm.

19. The back contact battery according to claim 1, characterized in that, The back contact battery also includes: A fifth passivation layer extends from the first passivation layer and is formed on the back side, the fifth passivation layer covering the edge region of the back side near the cut surface.

20. The back contact battery according to claim 7, characterized in that, The back contact battery also includes: A sixth passivation layer extends from the third passivation layer and is formed on the back side, the sixth passivation layer covering the edge region of the back side near the non-cut surface.

21. The back contact battery according to claim 1, characterized in that, Also includes: The metal electrode is disposed on the back side, and the thickness of the insulating member is greater than the thickness of the metal electrode.

22. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1 to 21.

23. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 22.

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