A back-contact battery, battery module and photovoltaic system

Abstract

This invention relates to the field of photovoltaic technology and provides a back-contact cell, cell module, and photovoltaic system. The back-contact cell includes: a silicon substrate; a first doped layer and a second doped layer disposed on the back side of the silicon substrate with opposite doping types; the first doped layer includes a first sub-doped layer extending along a first direction and a second sub-doped layer extending along a second direction, the second sub-doped layer and the second doped layer being alternately spaced along the first direction, and a first isolation region being disposed between the first sub-doped layer and the second doped layer; a welding region located on the first sub-doped layer; a first fine grid disposed on the second sub-doped layer, the first fine grid extending to the welding region; a second fine grid disposed on the second doped layer; and an insulating adhesive that at least covers the portion of the second fine grid near the welding region and fills at least a portion of the first isolation region. The back-contact cell of this invention can improve the welding yield of the cell and the solder ribbon.

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, and electrical energy is output through electrodes. In recent years, solar cell manufacturing technology has continuously improved, production costs have been decreasing, and conversion efficiency has been continuously improving. Solar cell power generation is becoming increasingly widespread and has become an important energy source for electricity supply. In particular, because the grid lines of back-contact cells are all located on the back side, the grid lines can avoid shading the front side of the cell, thus improving cell efficiency compared to bifacial cells.

[0003] In related technologies, the back side of a back contact cell typically has a first doped layer and a second doped layer with opposite doping types, and an isolation region is provided between the first doped layer and the second doped layer. In order to achieve the welding of the back contact cell and the solder ribbon to form a cell module, the back side of the back contact cell has a welding area for placing the solder ribbon, and the solder ribbon is placed in the corresponding fine grid or main grid connection of the welding area. However, when the solder ribbon is placed in the welding area to weld with the back contact cell, the solder ribbon is prone to positional displacement during the placement process, especially when the solder ribbon is shifted to the isolation area close to the welding area. Due to the height difference between the isolation area and the surrounding area, the solder ribbon is easily squeezed into the isolation area during the subsequent cell module lamination process, which causes the solder ribbon to curl up at the welding position, resulting in poor welding between the solder ribbon and the back contact cell, and thus affecting the welding yield of the cell and the solder ribbon. Summary of the Invention

[0004] This invention provides a back contact battery, which aims to solve the problem that in the prior art, the solder ribbon in the back contact battery is prone to shift to the isolation area, resulting in poor welding between the solder ribbon and the back contact battery, thereby affecting the welding yield of the battery cell and the solder ribbon.

[0005] This invention is implemented by providing a back contact battery, comprising: silicon substrate; A first doped layer and a second doped layer are disposed on the back side of the silicon substrate, the first doped layer and the second doped layer having opposite doping types; the first doped layer includes a first sub-doped layer and a second sub-doped layer, the first sub-doped layer extending along a first direction, the second sub-doped layer and the second doped layer both extending along a second direction, the second direction intersecting the first direction; the second sub-doped layer and the second doped layer are alternately spaced along the first direction, and a first isolation region is disposed between the first sub-doped layer and the second doped layer; A welding area is provided on the back side of the silicon substrate and used to provide a solder ribbon. The welding area is located on the first sub-doped layer and extends along the first direction. A first fine gate is disposed on the second sub-doped layer, and the first fine gate extends along the second direction to the welding area; A second fine gate is disposed on the second doped layer, and the second fine gate does not extend into the welding area; An insulating adhesive is disposed on the back side of the silicon substrate, the insulating adhesive at least covering the portion of the second fine gate near the soldering area, and the insulating adhesive filling at least a portion of the first isolation region.

[0006] Preferably, the insulating adhesive comprises: A main body portion located above the second doped layer, the main body portion at least covering the portion of the second fine gate near the solder area; and An extension connected to the main body, the extension filling at least a portion of the first isolation zone.

[0007] Preferred options also include: A first passivation layer covers the first doped layer, and the first fine gate passes through the first passivation layer and contacts the second sub-doped layer; A second passivation layer covers the second doped layer, the second fine gate passes through the second passivation layer and contacts the second doped layer, and the main body portion partially covers the second passivation layer.

[0008] Preferred options also include: A third passivation layer covers the first isolation region, and the extension portion partially covers the third passivation layer.

[0009] Preferably, the extension fills a portion of the first isolation zone.

[0010] Preferably, the ratio of the area of ​​the extension projected onto the silicon substrate to the area of ​​the first isolation region projected onto the silicon substrate is 0.3 to 0.8.

[0011] Preferably, the ratio of the dimension of the extension along the second direction to the dimension of the first isolation area along the second direction is 0.8 to 1.

[0012] Preferably, the ratio of the dimension of the extension along the first direction to the dimension of the first isolation area along the first direction is 0.2 to 0.5.

[0013] Preferably, the main body includes: The width of the first portion connected to the extension gradually decreases towards the welding area along the second direction.

[0014] Preferably, along the second direction, the thickness of the first portion gradually decreases towards the welding area.

[0015] Preferably, the first portion includes two oppositely disposed sides along the first direction, and the included angle between the two sides is 30° to 80°.

[0016] Preferably, along the second direction, the width of the extension gradually decreases towards the welding area.

[0017] Preferably, the main body further includes: A second portion connected to the first portion, the second portion extending along the second direction and in a direction away from the welding area.

[0018] Preferably, the main body further includes: A third portion connected to the second portion, the third portion extending along the second direction and away from the welding area, wherein the width of the second portion is greater than the width of the third portion.

[0019] Preferably, the insulating adhesive is disposed on both sides of the first sub-doped layer along the second direction, and the minimum distance between the first portions of the insulating adhesive on both sides of the first sub-doped layer along the second direction is d1, where d1 is 600~900 micrometers.

[0020] Preferably, the minimum distance between the second portions of the insulating adhesive on opposite sides of the first sub-doped layer along the second direction is d2, where d2 < 2d1.

[0021] Preferably, at least a portion of the surface of the extension is arc-shaped.

[0022] Preferably, a second isolation region is provided between the second sub-doped layer and the second doped layer, and the second isolation region is connected to the first isolation region.

[0023] The present invention also provides a battery assembly, comprising: The aforementioned back contact battery; A welding strip is provided in the welding area, and the welding strip is connected to the back contact battery.

[0024] The present invention also provides a photovoltaic system including the above-described battery module.

[0025] The present invention provides a back contact battery in which insulating adhesive is filled in at least a portion of a first isolation region, such that at least a portion of the first isolation region between a first sub-doped layer and a second doped layer is filled with insulating adhesive. When the back contact battery is welded to a solder ribbon to form a battery module, even if the solder ribbon shifts relative to the welding area to the first isolation region, the insulating adhesive in the first isolation region can support the solder ribbon. During the battery module lamination process, this prevents the solder ribbon from lifting at the welding position and causing the welding point to loosen, ensuring good welding between the solder ribbon and the back contact battery, thereby improving the welding yield of the battery cell and the solder ribbon, and thus improving the production yield of the battery module. Moreover, since the insulating adhesive fills at least a portion of the first isolation region, the insulating adhesive in the first isolation region can reflect sunlight emitted from the back of the silicon substrate back into the silicon substrate, which can increase the absorption of sunlight by the silicon substrate, improve the solar utilization rate of the back contact battery, and thus improve the battery power generation efficiency. Attached Figure Description

[0026] Figure 1 A partial schematic diagram of the back side of a back contact battery provided in an embodiment of the present invention; Figure 2 for Figure 1 A magnified schematic diagram of part A in the middle; Figure 3 Another partial schematic diagram of the back side of a back contact battery provided in an embodiment of the present invention; Figure 4 For along Figure 3 Cross-sectional view along the BB direction; Figure 5 This is a schematic diagram illustrating the welding of a back contact battery to a solder strip, as provided in an embodiment of the present invention. Detailed Implementation

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] Please refer to Figures 1-5 An embodiment of the present invention provides a back contact battery, comprising: Silicon substrate 1; A first doped layer 2 and a second doped layer 3 are disposed on the back side of the silicon substrate 1, and the doping types of the first doped layer 2 and the second doped layer 3 are opposite. The first doped layer 2 includes a first sub-doped layer 21 and a second sub-doped layer 22. The first sub-doped layer 21 extends along a first direction Y, and the second sub-doped layer 22 and the second doped layer 3 both extend along a second direction X, which intersects with the first direction Y. The second sub-doped layer 22 and the second doped layer 3 are alternately arranged along the first direction Y, and a first isolation region 41 is disposed between the first sub-doped layer 21 and the second doped layer 3. A welding area 5 is disposed on the back side of the silicon substrate 1 and used to set the solder ribbon 200. The welding area 5 is located on the first sub-doped layer 21 and extends along the first direction Y. A first fine gate 6 is disposed on the second sub-doped layer 22, and the first fine gate 6 extends along the second direction X to the welding area 5; A second fine gate 7 is disposed on the second doped layer 3, and the second fine gate 7 does not extend to the welding area 5; An insulating adhesive 8 is disposed on the back side of the silicon substrate 1, which at least covers the portion of the second fine gate 7 near the soldering region 5, and fills at least a portion of the first isolation region 41.

[0032] In this embodiment of the invention, the back contact battery can be a back contact battery without a main grid, that is, the first sub-doped layer 21 may not have a main grid, and the solder ribbon 200 is directly connected to the first fine grid 6 in the welding area 5; the back contact battery can be a back contact battery with a main grid, that is, the first sub-doped layer 21 may have a main grid, and the solder ribbon 200 is connected to the main grid in the welding area 5.

[0033] In this embodiment of the invention, the back side of the silicon substrate 1 is the side of the silicon substrate 1 that faces away from sunlight when the back-contact battery is working normally. The first doped layer 2 and the second doped layer 3 are, respectively, P-type and N-type doped layers. Specifically, the first doped layer 2 can be P-type and the second doped layer 3 can be N-type; or the first doped layer 2 can be N-type and the second doped layer 3 can be P-type. The P-type doped layer is doped with a P-type dopant, and the N-type doped layer is doped with an N-type dopant. The P-type dopant is a dopant of a Group IIIA element in the periodic table, and the N-type dopant is a dopant of a Group VA element in the periodic table. For example, the P-type dopant can be a boron dopant, and the N-type dopant can be a phosphorus dopant. The first doped layer 2 and the second doped layer 3 can be one or more of the following: doped polycrystalline silicon, doped amorphous silicon, and doped microcrystalline silicon. Preferably, both the first doped layer 2 and the second doped layer 3 are doped polycrystalline silicon layers.

[0034] In this configuration, there are multiple second sub-doped layers 22 and 3, which are alternately spaced along the first direction Y. A first isolation region 41 is provided between the first sub-doped layer 21 and the second doped layer 3, thus isolating them. The first isolation region 41 is specifically a trench. The second direction X may be perpendicular to the first direction Y, or it may not be perpendicular. Preferably, the second direction X is perpendicular to the first direction Y.

[0035] In this embodiment of the invention, there may be other functional layers between the silicon substrate 1 and the first doped layer 2, and between the silicon substrate 1 and the second doped layer 3, including but not limited to tunneling layers (not shown in the figures).

[0036] In this embodiment of the invention, the welding area 5 is used to provide the solder ribbon 200 so that the solder ribbon 200 can be welded to the first fine grid 6 or the main grid within the welding area 5, thereby achieving welding between the solder ribbon 200 and the back contact battery. The first fine grid 6 is disposed above the second sub-doped layer 22 and extends along the second direction X to the welding area 5 so that the first fine grid 6 can be welded to the solder ribbon 200 or facilitate the connection between the first fine grid 6 and the main grid on the first sub-doped layer 21. The second fine grid 7 is disposed on the second doped layer 3 and also extends along the second direction X. The second fine grid 7 does not extend to the welding area 5, that is, the second fine grid 7 is disconnected in the welding area 5 to avoid contact between the solder ribbon 200 and the second fine grid 7.

[0037] The insulating adhesive 8 provided in this embodiment of the invention covers at least the portion of the second fine grid 7 near the welding area 5 of the back contact battery. That is, the portion of the second fine grid 7 near the welding area 5 is covered by the insulating adhesive 8, preventing the solder ribbon 200 from contacting the second fine grid 7 of opposite polarity and causing a short circuit. Simultaneously, the insulating adhesive 8 fills at least a portion of the first isolation area 41. When the back contact battery and solder ribbon 200 are welded to form a battery assembly, even if the solder ribbon 200 shifts relative to the welding area 5 to the first isolation area 41, during the battery assembly lamination process, the insulating adhesive 8 within the first isolation area 41 supports the solder ribbon 200, preventing it from being suspended in the first isolation area 41. This prevents the solder ribbon 200 from curling up at the welding point (weld joint) during lamination, ensuring a good welding state between the solder ribbon 200 and the back contact battery. Improving the welding yield between the back contact cell and the solder ribbon 200 increases the production yield of the battery module. Furthermore, the presence of insulating adhesive 8 within the first isolation region 41 prevents the solder ribbon 200 from being squeezed into the first isolation region 41, thus preventing the battery module from turning black in the first isolation region 41 and improving its overall appearance. Additionally, since the insulating adhesive 8 fills at least a portion of the first isolation region 41, it can reflect sunlight emitted from the back of the silicon substrate 1 back into the silicon substrate 1, increasing the optical path of sunlight within the silicon substrate 1. This increases the absorption of sunlight by the silicon substrate 1, reduces the escape loss of sunlight from the first isolation region 41, improves the solar utilization rate of the back contact cell, and ultimately enhances the battery's power generation efficiency.

[0038] Please refer to Figure 1 and Figure 2 As an embodiment of the present invention, the insulating adhesive 8 comprises: The main body 81 located above the second doped layer 3, the main body 81 at least covers the portion of the second fine gate 7 near the solder area 5; and An extension 82 connected to the main body 81 fills at least a portion of the first isolation zone 41.

[0039] In this embodiment of the invention, the main body 81 can completely cover the second fine grid 7, or it can only cover the portion of the second fine grid 7 near the welding area 5. The extension 82 fills at least a portion of the first isolation area 41. This can be understood as the extension 82 filling the entire area of ​​the first isolation area 41, or it can only filling a portion of the first isolation area 41. In either case, the extension 82 can serve to support the solder strip 200. The main body 81 and the extension 82 are integrally formed, facilitating the printing and preparation of the insulating adhesive 8.

[0040] In this embodiment, the main body 81 of the insulating adhesive 8 is located above the second doped layer 3, and the main body 81 at least covers the portion of the second fine gate 7 near the soldering area 5 to prevent the solder ribbon 200 from contacting the second fine gate 7 and short-circuiting. The extension 82 is the portion of the insulating adhesive 8 that fills the first isolation region 41, and the extension 82 fills at least a portion of the first isolation region 41. When the solder ribbon 200 is offset from the welding area 5 to the first isolation area 41, the extension 82 can support the solder ribbon 200. During the lamination process of the battery module, it prevents the solder ribbon 200 from being pressed up and causing it to detach from the solder joint, ensuring good welding between the solder ribbon 200 and the back contact cell, thereby improving the welding yield between the solder ribbon 200 and the cell, and thus improving the production yield of the battery module. Moreover, the extension 82 fills at least a part of the first isolation area 41. The extension 82 can reflect the sunlight emitted from the back of the silicon substrate 1 back into the silicon substrate 1, which can increase the absorption of sunlight by the silicon substrate 1, improve the sunlight utilization rate of the back contact cell, and thus improve the power generation efficiency of the battery.

[0041] Please refer to Figure 3 and Figure 4 As one embodiment of the present invention, it further includes: A first passivation layer 91 covers a first doped layer 2, and a first fine gate 6 passes through the first passivation layer 91 and contacts a second sub-doped layer 21. The second passivation layer 92 covers the second doped layer 3, the second fine gate 7 passes through the second passivation layer 92 and contacts the second doped layer 3, and the main body portion 81 partially covers the second passivation layer 92.

[0042] In this embodiment, the first passivation layer 91 covers the first sub-doped layer 21 and the second sub-doped layer 22 of the first doped layer 2, and the second passivation layer 92 covers the second doped layer 3. The first passivation layer 91 and the second passivation layer 92 can be one or a combination of at least two of silicon nitride, silicon oxynitride, and silicon carbide layers. With the main body 81 covering at least a portion of the second fine gate 7, the main body 81 also covers portions of the second passivation layer 92 on both sides of the second fine gate 7. This improves the insulation effect between the second fine gate 7 and the first fine gate 6, and increases the alignment margin between the main body 81 and the second fine gate 7, preventing the main body 81 from being partially covered by the second fine gate 7 due to relative misalignment. Preferably, the first passivation layer 91 and the second passivation layer 92 are made of the same material, and the first passivation layer 91 and the second passivation layer 92 are an integral structure.

[0043] As one embodiment of the present invention, it also includes: The third passivation layer 93 covers the first isolation region 41, and the extension 82 partially covers the third passivation layer 93.

[0044] In this embodiment, the third passivation layer 93 covers the first isolation region 41, improving the passivation effect of the first isolation region 41 and preventing the extension 82 from directly contacting the silicon substrate 1. Preferably, the first passivation layer 91, the second passivation layer 92, and the third passivation layer 93 are made of the same material, and the first passivation layer 91, the second passivation layer 92, and the third passivation layer 93 are an integral structure.

[0045] As an embodiment of the present invention, a second isolation region 42 is provided between the second sub-doped layer 22 and the second doped layer 3, and the second isolation region 42 is connected to the first isolation region 41.

[0046] In this embodiment, the third passivation layer 93 also covers the second isolation region 42. The second isolation region 42 is used to achieve isolation between the second sub-doped layer 22 and the second doped layer 3. The second isolation region 42 is the same as the first isolation region 41, and both the second isolation region 42 and the first isolation region 41 are trenches. The second isolation region 42 and the first isolation region 41 are interconnected, that is, the second isolation region 42 and the first isolation region 41 are integrally formed.

[0047] Please refer to this again. Figure 1 and Figure 2 In a preferred embodiment of the present invention, the extension 82 fills a portion of the first isolation region 41.

[0048] In this embodiment, the extension 82 only fills a portion of the first isolation zone 41, leaving a portion of the first isolation zone 41 unfilled with insulating adhesive 8. This prevents the extension 82 from becoming too large and avoids the insulating adhesive 8 material flowing into the welding zone 5 during lamination, which could cause a poor weld on the solder strip 200. Therefore, by filling a portion of the first isolation zone 41 with the extension 82, the solder strip 200 can be supported when it shifts relative to the welding zone 5 into the first isolation zone 41. At the same time, by preventing the extension 82 from becoming too large, the material of the extension 82 can be prevented from flowing into the welding zone 5 and causing a poor weld on the solder strip 200.

[0049] In a preferred embodiment of the present invention, the first isolation area 41 is not filled with the material of the insulating adhesive 8 in the areas on opposite sides of the extension 82 along the first direction Y. Only the middle area of ​​the first isolation area 41 is filled with the extension 82, which can better prevent the material of the extension 82 from flowing to the welding area 5 and causing the solder strip 200 to be poorly soldered.

[0050] As an embodiment of the present invention, the ratio of the area of ​​the extension 82 projected onto the silicon substrate 1 to the area of ​​the first isolation region 41 projected onto the silicon substrate 1 is 0.3 to 0.8.

[0051] In this embodiment, the ratio of the projected area of ​​the extension 82 on the silicon substrate 1 to the projected area of ​​the first isolation region 41 on the silicon substrate 1 is controlled to be 0.3 to 0.8. This ensures that the extension 82 provides good support for the solder ribbon 200 when it shifts to the first isolation region 41, and also prevents the material of the insulating adhesive 8 from flowing into the welding area 5 due to the excessive area of ​​the extension 82, thus preventing the solder ribbon 200 from being poorly soldered. This achieves both effects.

[0052] As an embodiment of the present invention, the ratio of the dimension of the extension 82 along the second direction X to the dimension L4 of the first isolation region 41 along the second direction X is 0.8 to 1.

[0053] In this embodiment, the dimension of the extension 82 along the second direction X is the maximum dimension of the extension 82 along the second direction X, and the dimension L4 of the first isolation zone 41 along the second direction X is the maximum dimension of the first isolation zone 41 along the second direction X. The maximum dimension of the extension 82 along the second direction X and the maximum dimension of the first isolation zone 41 along the second direction X can be equal or unequal. Controlling the ratio of the dimension of the extension 82 along the second direction X to the dimension L4 of the first isolation zone 41 along the second direction X to be 0.8~1 can ensure that the extension 82 provides good support for the solder strip 200 when it shifts to the first isolation zone 41, and can also prevent the material of the extension 82 from flowing into the welding area 5 and causing a poor solder joint on the solder strip 200.

[0054] As an embodiment of the present invention, the ratio of the dimension L6 of the extension 82 along the first direction Y to the dimension L5 of the first isolation region 41 along the first direction Y is 0.2 to 0.5.

[0055] In this embodiment, the dimension L6 of the extension 82 along the first direction Y is the maximum dimension of the extension 82 along the second direction X, and the dimension L5 of the first isolation zone 41 along the first direction Y is the maximum dimension of the first isolation zone 41 along the first direction Y. By controlling the ratio of the dimension L6 of the extension 82 along the first direction Y to the dimension L5 of the first isolation zone 41 along the first direction Y to be 0.2 to 0.5, the extension 82 can provide better support for the solder strip 200 when it shifts to the first isolation zone 41, and can also prevent the material of the extension 82 from flowing into the welding zone 5 and causing the solder strip 200 to have a poor weld.

[0056] As an embodiment of the present invention, the main body 81 includes: The width L1 of the first portion 811 connected to the extension 82 gradually decreases towards the welding area 5 along the second direction X.

[0057] In this embodiment, the first portion 811 covers the portion of the second fine grid 7 near the welding area 5, preventing the second fine grid 7 from contacting the solder strip 200. The width L1 of the first portion 811 is its dimension along the first direction Y. The width L1 of the first portion 811 gradually decreases along the second direction X towards the welding area 5. This can be understood as the width of the first portion 811 decreasing as it approaches the welding area 5 and increasing as it moves further away from the welding area 5. This prevents the insulating adhesive 8 material from flowing into the welding area 5 and causing a weak solder joint in the solder strip 200, and also facilitates the formation of an extension 82 in the middle of the first isolation area 41 after heating and extrusion.

[0058] As an embodiment of the present invention, along the second direction X, the thickness of the first portion 811 gradually decreases towards the welding area 5.

[0059] This can be understood as follows: the thickness of the first part 811 is smaller as it gets closer to the welding area 5, and the thickness of the first part 811 is larger as it gets further away from the welding area 5. This can prevent the material of the first part 811 from flowing into the welding area 5 and causing a cold solder joint on the solder strip 200. The surface of the first part 811 away from the silicon substrate 1 can be arc-shaped or inclined, thereby achieving a gradual change in the thickness of the first part 811.

[0060] As an embodiment of the present invention, the first part 811 includes two sides 8110 disposed opposite each other along the first direction Y, and the included angle between the two sides 8110 is 30°~80°.

[0061] In this embodiment, the two sides 8110 of the first part 811 intersect and are arranged to control the included angle between the two sides 8110 of the first part 811 to be 30°~80°. This can further prevent the material of the first part 811 from flowing to the welding area 5 and causing the solder strip 200 to be poorly welded, and facilitate the flow of some material of the first part 811 to the first isolation area 41 to form the extension 82, which is convenient for the processing of the extension 82.

[0062] As an embodiment of the present invention, along the second direction X, the width of the extension 82 gradually decreases toward the welding area 5.

[0063] In this embodiment, the width of the extension 82 is the dimension of the extension 82 along the first direction Y. The width of the extension 82 gradually decreases along the second direction X and toward the welding area 5. The closer the extension 82 is to the welding area 5, the smaller its width becomes, which can better prevent the material of the extension 82 from flowing to the welding area 5 and causing the solder strip 200 to be poorly soldered.

[0064] As an embodiment of the present invention, the main body 81 further includes: The second part 812 is connected to the first part 811 and extends along the second direction X and away from the welding area 5.

[0065] In this embodiment, the second part 812 is used to cover and protect the part of the second fine grid 7 that is away from the welding area 5, which can improve the insulation effect between the first fine grid 6 and the second fine grid 7.

[0066] As an embodiment of the present invention, the main body 81 further includes: The third part 813 is connected to the second part 812. The third part 813 extends along the second direction X and away from the welding area 5. The width of the second part 812 is greater than the width of the third part 813.

[0067] In this embodiment, the third portion 813 is used to cover and protect the portion of the second fine grid 7 that is far from the welding area 5, which can improve the insulation effect between the first fine grid 6 and the second fine grid 7. The width of the second portion 812 is the dimension of the second portion 812 along the first direction Y, and the width of the third portion 813 is the dimension of the third portion 813 along the first direction Y. Controlling the width of the second portion 812 to be greater than the width of the third portion 813 is beneficial to increase the width of the second portion 812, thereby increasing the alignment allowance between the second portion 812 and the second fine grid 7, preventing the second portion 812 from not covering the second fine grid 7 due to relative misalignment between the second portion 812 and the second fine grid 7, and improving the reliability of the second portion 812 covering the second fine grid 7; moreover, the width of the third portion 813 is smaller than the width of the second portion 812, which is beneficial to reduce the material usage of the third portion 813 and reduce production costs.

[0068] Please refer to this again. Figure 1 As an embodiment of the present invention, insulating adhesive 8 is provided on both sides of the first sub-doped layer 21 along the second direction X, and the minimum distance between the first portions 811 of the insulating adhesive 8 on both sides of the first sub-doped layer 21 along the second direction X is d1, where d1 is 600~900 micrometers.

[0069] In this embodiment, a second sub-doped layer 22 and a second doped layer 3 are disposed on opposite sides of the first sub-doped layer 21 along the second direction X. Insulating adhesive 8 is disposed on opposite sides of the first sub-doped layer 21 along the second direction X, and an extension portion 82 is filled in the first isolation region 41 between adjacent first sub-doped layers 21 and second doped layers 3. The first sub-doped layer 21 is connected to the second sub-doped layers 22 on both sides of the second direction X, and the first sub-doped layer 21 is isolated from the second doped layers 3 on both sides of the second direction X by the first isolation region 41.

[0070] The minimum distance between the first portions 811 of the insulating adhesive 8 on opposite sides of the first sub-doped layer 21 along the second direction X is the distance d1 between the nearest endpoints of the first portions 811 on opposite sides of the welding area 5 along the second direction X. Controlling d1 to 600~900 micrometers avoids excessively large d1, which facilitates the formation of extensions 82 of the insulating adhesive 8 in the first isolation area 41 during heating and extrusion of the first sub-doped layer 21 along the second direction X. This facilitates the processing and shaping of the extensions 82, and also avoids excessively small d1, preventing the insulating adhesive 8 material from entering the welding area 5 and causing incomplete soldering of the solder strip 200.

[0071] As an embodiment of the present invention, the minimum distance between the second portions 812 of the insulating adhesive 8 on opposite sides of the first sub-doped layer 21 along the second direction X is d2, where d2 < 2d1.

[0072] In this embodiment, the minimum distance between the second portions 812 of the insulating adhesive 8 located on opposite sides of the first sub-doped layer 21 along the second direction X is the distance between the nearest endpoints of the second portions 812 of the insulating adhesive 8 on opposite sides of the first sub-doped layer 21 along the second direction X. Controlling d2 < 2d1 further facilitates the formation of extensions 82 of the insulating adhesive 8 in the first isolation region 41 during heating and extrusion, thus facilitating the processing and shaping of the extensions 82.

[0073] As an embodiment of the present invention, at least a portion of the surface of the extension 82 is provided as an arc surface.

[0074] In this embodiment, since at least a portion of the surface of the extension 82 is curved, sunlight emitted from the back side of the silicon substrate 1 can be better reflected back into the silicon substrate 1 through the curved surface of the extension 82, which can further increase the absorption of sunlight by the silicon substrate 1, improve the sunlight utilization rate of the back contact battery, and thus improve the battery power generation efficiency. Specifically, the extension 82 can be spherical or hemispherical in shape. Of course, the extension 82 can also be other regular or irregular shapes.

[0075] As an embodiment of the present invention, the insulating adhesive 8 has an average reflectivity of 50% to 95% for light with a wavelength range of 800nm ​​to 1200nm, which enables the extension 82 of the first isolation region 41 to have a good light reflection effect, which is beneficial for the extension 82 of the first isolation region 41 to reflect the sunlight emitted from the back side of the silicon substrate 1 back into the silicon substrate 1. Please refer to the reference. Figure 1 and Figure 5 The present invention also provides a battery assembly, which includes: The back contact battery of the above embodiment; The welding strip 200 is located in the welding area 5 and is connected to the back contact battery.

[0076] It should be noted that this battery assembly has the same or similar beneficial effects as the aforementioned back contact battery, and the relevant aspects between the two can be referenced. To avoid repetition, they will not be elaborated here.

[0077] In this embodiment, multiple back-contact batteries in the battery assembly are connected in series by solder strips 200 to form a battery string, thereby achieving series current collection and output.

[0078] 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 surfaces of the back-contact battery, 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.

[0079] Photovoltaic glass can be applied to the encapsulating film on the front side of the back contact battery. This photovoltaic glass can be ultra-clear glass, possessing 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%, protecting the back contact battery while minimizing impact on its efficiency. Simultaneously, the encapsulating film bonds the photovoltaic glass and the back contact battery together, providing sealing, insulation, and waterproofing / moisture protection for the battery.

[0080] The backsheet can be attached to the adhesive film on the back side of the back contact cell. The backsheet protects and supports the back contact cell, providing reliable insulation, water resistance, and aging resistance. Multiple backsheet options are available, typically including tempered glass, acrylic glass, aluminum alloy TPT composite adhesive film, etc., and the specific choice depends on the specific circumstances and is not limited here. The backsheet, back contact cell, 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.

[0081] 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 described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.

[0082] 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.

[0083] 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.

[0084] 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 scope of protection of the present invention.

Claims

1. A back-contact battery, characterized in that, include: silicon substrate; A first doped layer and a second doped layer are disposed on the back side of the silicon substrate, the first doped layer and the second doped layer having opposite doping types; the first doped layer includes a first sub-doped layer and a second sub-doped layer, the first sub-doped layer extending along a first direction, the second sub-doped layer and the second doped layer both extending along a second direction, the second direction intersecting the first direction; the second sub-doped layer and the second doped layer are alternately spaced along the first direction, and a first isolation region is disposed between the first sub-doped layer and the second doped layer; A welding area is provided on the back side of the silicon substrate and used to provide a solder ribbon. The welding area is located on the first sub-doped layer and extends along the first direction. A first fine gate is disposed on the second sub-doped layer, and the first fine gate extends along the second direction to the welding area; A second fine gate is disposed on the second doped layer, and the second fine gate does not extend into the welding area; An insulating adhesive is disposed on the back side of the silicon substrate, the insulating adhesive at least covering the portion of the second fine gate near the soldering area, and the insulating adhesive filling at least a portion of the first isolation region.

2. The back contact battery according to claim 1, characterized in that, The insulating adhesive includes: A main body portion located above the second doped layer, the main body portion at least covering the portion of the second fine gate near the solder area; and An extension connected to the main body, the extension filling at least a portion of the first isolation zone.

3. The back contact battery according to claim 2, characterized in that, Also includes: A first passivation layer covers the first doped layer, and the first fine gate passes through the first passivation layer and contacts the second sub-doped layer; A second passivation layer covers the second doped layer, the second fine gate passes through the second passivation layer and contacts the second doped layer, and the main body portion partially covers the second passivation layer.

4. The back contact battery according to claim 3, characterized in that, Also includes: A third passivation layer covers the first isolation region, and the extension portion partially covers the third passivation layer.

5. The back contact battery according to claim 2, characterized in that, The extension fills a portion of the first isolation zone.

6. The back contact battery according to claim 5, characterized in that, The ratio of the area of ​​the extension projected onto the silicon substrate to the area of ​​the first isolation region projected onto the silicon substrate is 0.3 to 0.

8.

7. The back contact battery according to claim 2, characterized in that, The ratio of the dimension of the extension along the second direction to the dimension of the first isolation area along the second direction is 0.8 to 1.

8. The back contact battery according to claim 2, characterized in that, The ratio of the dimension of the extension along the first direction to the dimension of the first isolation area along the first direction is 0.2 to 0.

5.

9. The back contact battery according to claim 2, characterized in that, The main body includes: The width of the first portion connected to the extension gradually decreases towards the welding area along the second direction.

10. The back contact battery according to claim 9, characterized in that, Along the second direction, the thickness of the first portion gradually decreases towards the welding area.

11. The back contact battery according to claim 9, characterized in that, The first part includes two oppositely arranged sides along the first direction, and the included angle between the two sides is 30° to 80°.

12. The back contact battery according to claim 2, characterized in that, Along the second direction, the width of the extension gradually decreases toward the welding area.

13. The back contact battery according to claim 9, characterized in that, The main body also includes: A second portion connected to the first portion, the second portion extending along the second direction and in a direction away from the welding area.

14. The back contact battery according to claim 13, characterized in that, The main body also includes: A third portion connected to the second portion, the third portion extending along the second direction and away from the welding area, wherein the width of the second portion is greater than the width of the third portion.

15. The back contact battery according to claim 13, characterized in that, The insulating adhesive is disposed on both sides of the first sub-doped layer along the second direction, and the minimum distance between the first portions of the insulating adhesive on both sides of the first sub-doped layer along the second direction is d1, where d1 is 600~900 micrometers.

16. The back contact battery according to claim 15, characterized in that, The minimum distance between the second portions of the insulating adhesive on opposite sides of the first sub-doped layer along the second direction is d2, where d2 < 2d1.

17. The back contact battery according to claim 2, characterized in that, At least a portion of the surface of the extension is arc-shaped.

18. The back contact battery according to claim 1, characterized in that, A second isolation region is provided between the second sub-doped layer and the second doped layer, and the second isolation region is connected to the first isolation region.

19. A battery assembly, characterized in that, include: The back contact battery as described in any one of claims 1 to 18; A welding strip is provided in the welding area, and the welding strip is connected to the back contact battery.

20. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 19.

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