A solar cell and photovoltaic module

Abstract

This invention discloses a solar cell and a photovoltaic module, relating to the field of photovoltaic technology, and addresses the stress problem between a metal electrode and the cell body. The solar cell includes: a cell body; a metal electrode disposed on a target surface of the cell body, the target surface including at least one side of the cell body, the metal electrode being in conductive contact with the cell body, and the metal electrode including a metal layer; and a buffer layer disposed on the target surface, with a buffer layer between a local area of ​​the metal electrode and the target surface. Compared to a pure metal electrode being entirely in direct contact with the cell body, this application solves the stress mismatch problem between the metal electrode and the fragile functional layers in the cell body by placing a buffer layer under a local area of ​​the metal electrode. This effectively absorbs and disperses the stress generated by the pure metal electrode. It suppresses unreliable bonding between the metal electrode and the cell body film layers caused by stress, as well as metal electrode warping and detachment, thereby improving the reliability of the bonding between the metal electrode and the cell body film layers.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic technology, and more particularly to a solar cell and a photovoltaic module. Background Technology

[0002] The main methods for preparing electrodes for solar cells are screen printing and physical vapor deposition (PVD).

[0003] When screen printing is used to prepare electrodes for certain high-temperature-sensitive solar cells, such as perovskite cells, the curing temperature of the screen-printed paste is required to be low. However, pastes with low curing temperatures often contain organic matter in the cured electrodes, resulting in poorer conductivity than pure metals and affecting cell efficiency.

[0004] To improve electrode conductivity, PVD technology can be used to directly deposit metal electrodes onto the cell substrate. However, PVD technology presents stress issues between the metal electrodes and the cell substrate, which may reduce the reliability of the electrode-film bonding in solar cells, or even cause the film to detach. Summary of the Invention

[0005] The purpose of this invention is to provide a solar cell and a photovoltaic module to improve the reliability of the bonding between the metal electrode and the battery film layer.

[0006] In a first aspect, the present invention provides a solar cell, comprising: The battery body has two opposing sides; A metal electrode is disposed on a target surface of the battery body; the target surface includes at least one side of the battery body, and the metal electrode is in conductive contact with the battery body; the metal electrode includes a metal layer; A buffer layer is disposed on the target surface; a buffer layer is provided between the battery body and the metal electrode, and between a local area of ​​the metal electrode and the target surface.

[0007] With the above technical solution, the metal electrode of the solar cell is in conductive contact with the battery body, and a buffer layer is provided between a local area of ​​the metal electrode and the target surface of the battery body. Compared to a pure metal electrode that is entirely in direct contact with the target surface of the battery body, this application solves the stress mismatch problem between the metal electrode and the fragile functional layers in the battery body by placing a buffer layer under a local area of ​​the metal electrode. This effectively absorbs and disperses the stress generated by the pure metal electrode, thus suppressing problems such as unreliable bonding between the metal electrode and the battery body film layer, metal electrode warping and detachment, and film layer delamination, cracking, and detachment in the battery body caused by stress, thereby improving the bonding reliability between the metal electrode and the battery body film layer.

[0008] In some possible implementations, the buffer layer is selected from a conductive material layer or an organic material layer.

[0009] In some possible implementations, the conductive material layer is selected from a metal paste layer; the metal paste layer is selected from one or more combinations of silver paste layer, copper paste layer, aluminum paste layer, and silver-coated copper paste layer.

[0010] In some possible implementations, the organic material layer includes one or more combinations of curing adhesives, epoxy adhesives, acrylics, polyurethanes, and silicones.

[0011] In some possible implementations, the metal electrode includes multiple metal grid lines extending along a first direction and spaced apart along a second direction, the first direction intersecting the second direction, and a buffer layer between a local area of ​​the metal grid lines and the target surface.

[0012] In some possible implementations, the area of ​​the local region on each metal grid line that contacts the buffer layer accounts for 1% to 15% of the total area of ​​the metal grid line.

[0013] In some possible implementations, the buffer layer includes multiple spaced buffer blocks, with at least one buffer block between each metal grid line and the target surface.

[0014] In some possible implementations, the maximum size d1 of the buffer block along the first direction is greater than or equal to 20 μm and less than or equal to 200 μm; and / or, the maximum size L1 of the buffer block along the second direction is greater than or equal to 10 μm and less than or equal to 200 μm.

[0015] In some possible implementations, in the second direction, the maximum size L1 of the buffer block is greater than or equal to the width L2 of the metal grid line, and / or less than or equal to the spacing between two adjacent metal grid lines.

[0016] In some possible implementations, in the second direction, the ratio of the maximum size L1 of the buffer block to the width L2 of the metal grid line is 1:1 to 1:1.5.

[0017] In some possible implementations, the ratio of the maximum size L1 of the buffer block along the second direction to the maximum size d1 of the buffer block along the first direction is 10:1 to 1:1.

[0018] In some possible implementations, the spacing d2 between two adjacent buffer blocks along the first direction is 3370μm to 91000μm; and or, in the first direction, the ratio of the spacing d2 between two adjacent buffer blocks to the maximum size d1 of the buffer block along the first direction is 33:1 to 4550:1.

[0019] In some possible implementations, when the buffer layer is selected from a conductive material layer, there are 1 to 54 buffer blocks between each metal gate line and the target surface; Alternatively, when the buffer layer is selected from an organic material layer, each metal grid line is connected to the target surface by 1 to 17 buffer blocks.

[0020] In some possible implementations, multiple buffer blocks corresponding to each metal grid line are evenly distributed along the extension direction of the metal grid line.

[0021] In some possible implementations, the thickness h2 of the buffer layer is 1 μm to 100 μm, and the thickness h1 of the metal electrode is 0.1 μm to 10 μm; And / or, the ratio of the thickness h1 of the metal electrode to the thickness h2 of the buffer layer is 1:80 to 1:5.

[0022] In some possible implementations, the battery body is a perovskite battery body or a perovskite-silicon tandem battery body.

[0023] Secondly, the present invention also provides a photovoltaic module, comprising: A battery string, which is formed by electrically connecting a plurality of solar cells as described in any of the above; Interconnectors are electrically connected to the solar cells; And an encapsulation layer that covers the surface of the battery string.

[0024] Since photovoltaic modules use solar cells described in any of the above descriptions, they have the same beneficial effects as the aforementioned solar cells, and will not be elaborated further. Attached Figure Description

[0025] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A top view schematic diagram of a solar cell provided in an embodiment of the present invention; Figure 2 for Figure 1 Schematic diagram of section AA; Figure 3 for Figure 1 Schematic diagram of the structure of section BB; Figure 4 for Figure 1 A partially enlarged schematic diagram of the solar cells in the image; Figure 5 A top view schematic diagram of another solar cell provided in an embodiment of the present invention; Figure 6 This is a top view schematic diagram of another type of solar cell provided in an embodiment of the present invention.

[0026] Reference numerals: 1 is a metal electrode, 11 is a metal grid line, 2 is a buffer layer, 21 is a buffer block, and 3 is the battery body. Detailed Implementation

[0027] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0028] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. "Several" means one or more, unless otherwise explicitly specified.

[0030] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.

[0031] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0032] like Figures 1-3As shown, this embodiment of the invention provides a solar cell, including a cell body 3, a metal electrode 1, and a buffer layer 2. The cell body 3 refers to the main part of the solar cell excluding the metal electrode 1, and may include a semiconductor substrate and various functional film layers disposed on the semiconductor substrate to form a PN junction, enabling photogenerated carriers and carrier transport. The cell body 3 has two opposing sides, at least one of which is a target surface for disposing of the metal electrode 1. The metal electrode 1 is disposed on the target surface of the cell body 3, and the metal electrode 1 is in conductive contact with the target surface. The metal electrode 1 includes a metal layer and is a pure metal electrode. The metal layer is formed on the target surface of the cell body 3 by physical vapor deposition (PVD), etc., and is relatively thin and contains almost no organic components. The buffer layer 2 is disposed on the target surface of the cell body 3. A buffer layer 2 is provided between a local area of ​​the metal electrode 1 and the target surface; that is, the buffer layer 2 is not a whole layer, but a local layer disposed on the cell body 3, and located below the local area of ​​the metal electrode 1, so that the local area of ​​the metal electrode 1 does not directly contact the cell body 3. Figure 2 The structure shown has the following components stacked sequentially from top to bottom at the location where the buffer layer 2 is provided: metal electrode 1, buffer layer 2, and battery body 3. The remaining areas of the metal electrode 1 maintain conductive contact with the battery body 3. Figure 3 In the structure shown, where the buffer layer 2 is not present, the metal electrode 1 and the battery body 3 are stacked sequentially from top to bottom. The buffer layer 2 has the function of stress absorption and dispersion.

[0033] With the above technical solution, the metal electrode 1 of the solar cell is in conductive contact with the battery body 3, and a buffer layer 2 is provided between a local area of ​​the metal electrode 1 and the target surface of the battery body 3. Compared with pure metal electrodes that are in direct contact with the surface of the battery body, this application provides a buffer layer 2 under a local area of ​​the metal electrode 1. The buffer layer 2 effectively absorbs and disperses the stress generated by the pure metal electrode 1, significantly reducing the interfacial stress and solving the stress mismatch problem between the metal electrode 1 and the fragile functional layers in the battery body 3. This suppresses problems such as unreliable bonding between the metal electrode 1 and the battery body 3 film layers caused by stress, metal electrode warping and detachment, and film layer delamination, cracking, and detachment in the battery body. Without affecting the conductivity of the metal electrode, the bonding reliability between the metal electrode 1 and the battery body 3 film layers is improved.

[0034] In some embodiments, the buffer layer 2 is selected from a conductive material layer or an organic material layer. That is, the buffer layer 2 can be conductive or non-conductive. Organic material layers are non-conductive, as long as they can effectively absorb and disperse the stress of the deposited pure metal electrode. For example, a buffer layer 2 of size 1.5cm × 1.5cm is provided on the battery body 3, and a metal electrode 1 is made on it. Using a 1cm wide peel test tape, the tensile force at 90°C is tested using a tensile testing machine at a speed of 300mm / min. If the tensile force is >70gf / cm, the material of the buffer layer 2 meets the requirements for use, preferably >150gf / cm.

[0035] For example, when the buffer layer 2 is selected from a conductive material layer, the conductive material layer can be selected from a metal paste layer containing conductive metals and other organic matter, and can be the electrode paste used in screen printing. This achieves both stress buffering and conductivity, with virtually no impact on the conductivity of the metal electrode 1. Furthermore, compared to electrodes fabricated entirely using metal paste through screen printing, the metal paste used in the buffer layer 2 is only placed below a localized area of ​​the metal electrode, and the amount used is very small. Therefore, it avoids the problem of excessive organic matter affecting conductivity, as seen in screen-printed electrodes. By optimizing the pattern, size, and material of the buffer layer prepared from conductive materials, the impact on the battery series resistance and fill factor can be minimized while ensuring stress buffering, and the conductive buffer layer can even be used to improve current collection.

[0036] For example, the metal paste layer is selected from one or more combinations of silver paste, copper paste, aluminum paste, and silver-coated copper paste. The metal paste layer refers to the layer formed after the original paste has been cured. For example, the layer formed by silver paste is called a silver paste layer, the layer formed by copper paste is a copper paste layer, and the layer formed by aluminum paste is an aluminum paste layer. The buffer layer 2 can be selected from the same type of metal paste layer for ease of preparation, or it can be a combination of multiple different metal paste layers. For example, the buffer layer 2 can be prepared by stacking different metal paste layers, or by mixing different metal pastes, or different regions of the buffer layer 2 can use different metal paste layers. As long as a buffer layer that can absorb and disperse the stress of the deposited pure metal electrode can be obtained, it is not limited to the forms listed in this embodiment.

[0037] It should be noted that the metal contained in the metal paste layer in the conductive material layer may be the same as or different from the metal used in the metal electrode. This application does not limit this, and those skilled in the art can make flexible choices according to actual needs.

[0038] In other embodiments, when the buffer layer 2 is selected from organic material layers, the organic material layer may include one or more combinations of curing adhesive, epoxy adhesive, acrylic, polyurethane, and silicone. For example, the curing adhesive may be UV insulating adhesive, UV green adhesive, thermosetting adhesive, etc. The buffer layer 2 may be selected from the same organic material layer for ease of preparation, or it may be a combination of multiple different organic material layers. For example, the buffer layer 2 may be prepared by stacking different organic material layers, or by mixing different organic materials, or different regions of the buffer layer 2 may use different organic material layers, as long as a buffer layer 2 that can absorb and disperse the stress of the deposited pure metal electrode can be obtained, and it is not limited to the forms listed in this embodiment.

[0039] like Figure 1 , Figure 5 and Figure 6 As shown, in some embodiments, the metal electrode 1 includes multiple metal grid lines 11 extending along a first direction, and the multiple metal grid lines 11 are spaced apart along a second direction. The first direction and the second direction intersect, for example, the first direction and the second direction are perpendicular. A buffer layer 2 is provided between a local area of ​​the metal grid line 11 and the target surface of the battery body 3. The metal grid line 11 can be a current collector grid line for collecting the current of the battery body. In some embodiments, the metal grid line 11 can also include a current collector grid line and a current collector grid line connected together. The current collector grid line is used to collect the current collected by the current collector grid line and then conduct it to the interconnects of the photovoltaic module (such as solder ribbon, conductive adhesive, etc.). The lower part of a local area of ​​each metal grid line 11 is in contact with the buffer layer 2, but not directly in contact with the battery body 3. The lower part of the remaining area of ​​each metal grid line 11 is in direct conductive contact with the battery body 3. The buffer layer 2 can effectively absorb and disperse the stress generated by the deposited pure metal metal grid line 11, solving the stress mismatch problem between the metal grid line 11 and the fragile functional layer in the battery body 3. It suppresses problems such as unreliable bonding between the metal grid line 11 and the film layer of the battery body 3 caused by stress, warping and detachment of the metal grid line 11, and delamination, cracking and detachment of the film layer in the battery body 3. Without affecting the conductivity of the metal grid line 11, it improves the bonding reliability between the metal grid line 11 and the film layer of the battery body 3.

[0040] In some embodiments, the area of ​​the local region on each metal grid line 11 that contacts the buffer layer 2 accounts for 1% to 15% of the total area of ​​the metal grid line 11. For example, the area percentage can be 1%, 3%, 5%, 7%, 9%, 11%, 13%, 15%, etc. If the area percentage is less than 1%, the area of ​​the buffer layer 2 is too small, which cannot effectively absorb and disperse the stress of the metal grid line 11 and cannot effectively improve the bonding reliability between the metal grid line 11 and the buffer layer 2. If the area percentage is greater than 15%, the area of ​​the buffer layer 2 is too large, which will have a significant impact on the conductivity of the metal grid line 11. Therefore, considering both the stress and conductivity of the metal grid line 11, the area percentage in this application is selected as 1% to 15%. The area percentage of the local region that contacts the buffer layer 2 on different metal grid lines 11 can be the same, which simplifies the fabrication of the screen structure of the buffer layer 2. Of course, the area percentage can also be different.

[0041] like Figure 1 , Figure 5 and Figure 6 As shown, in some embodiments, the buffer layer 2 includes a plurality of spaced buffer blocks 21, with at least one buffer block 21 between each metal grid line 11 and the target surface. For example, when there are multiple buffer blocks 21 between each metal grid line 11 and the target surface, the multiple buffer blocks 21 below each metal grid line 11 are spaced apart along the extension direction of the metal grid line 11 (i.e., the first direction). The buffer blocks 21 can also be spaced apart in a second direction, such that all the buffer blocks 21 constituting the buffer layer 2 are arranged in an array. Of course, the number and position of the buffer blocks 21 below each metal grid line 11 can be the same or different, as long as they can provide stress buffering for each metal grid line 11.

[0042] In some embodiments, when the buffer layer 2 is selected from a conductive material layer, each metal grid line 11 has 1 to 54 buffer blocks 21 between it and the target surface. For example, each metal grid line 11 may have 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, or 54 buffer blocks 21 placed under it, as long as the area of ​​the local region in contact with all the buffer blocks 21 accounts for 1% to 15%. Further, each metal grid line 11 may have 3 to 18 buffer blocks 21 placed under it, for example, 3, 5, 7, 9, 11, 13, 15, or 18. Since the buffer layer 2 is selected from a conductive material layer, a relatively large number of buffer blocks 21 can be provided, improving the absorption and dispersion of stress on the metal grid line 11 without affecting its conductivity.

[0043] In other embodiments, when the buffer layer 2 is selected from an organic material layer, there are 1 to 17 buffer blocks 21 between each metal grid line 11 and the target surface. For example, 1, 3, 5, 8, 10, 12, 15, 17, etc., are placed under each metal grid line 11, as long as the area of ​​the local region in contact with all buffer blocks 21 accounts for 1% to 15%. Further, 2 to 7 buffer blocks are placed under each metal grid line 11, for example, 2, 3, 4, 5, 6, 7. Since the buffer layer 2 is selected from an organic material layer and is non-conductive, the number of buffer blocks 21 in the organic material layer is relatively less than that in the conductive material layer. While meeting the requirements for stress absorption and dispersion of the metal grid line 11, the influence of the non-conductive buffer blocks 21 on the conductivity of the metal grid line 11 is reduced.

[0044] Regardless of whether the buffer blocks 21 are selected from conductive material layers or organic material layers, the number of buffer blocks 21 under each metal grid line 11 can be the same or different, and their arrangement positions can be the same or different. When the number and arrangement positions of the buffer blocks 21 under each metal grid line 11 are the same, the fabrication of the buffer blocks 21 on the battery body 3 can be simplified. Of course, different numbers and arrangement positions can also be selected according to the specific structure on the battery body 3 to optimize current collection.

[0045] In some embodiments, such as Figure 1 As shown, the buffer blocks 21 below each metal grid line 11 are uniformly distributed along the first direction, i.e., equally spaced, to improve the uniformity of stress absorption and dispersion. Alternatively, as... Figure 5 As shown, the buffer blocks 21 below each metal grid line 11 are not uniformly distributed along the first direction, that is, not evenly spaced, and can be arranged more densely in places where stress is relatively concentrated.

[0046] In some embodiments, the shape of the buffer block 21 can be a rectangular block, a circular block, a triangular block, a trapezoidal block, a polygonal block, etc., as long as it can be placed under the metal grid line 11, and is not limited to the shapes listed in this embodiment. Figure 4 As shown, the maximum dimension d1 of the buffer block 21 along the first direction is greater than or equal to 20 μm and less than or equal to 200 μm, for example, as Figure 1 and Figure 4 As shown, when the buffer block 21 is rectangular, and the length direction of the rectangular block is parallel to the second direction, and the width direction is parallel to the first direction, then the maximum dimension d1 of the buffer block 21 along the first direction is the width d1 of the rectangular block. Figure 6As shown, if the length direction of the rectangular block is parallel to the first direction and the width direction is parallel to the second direction, then the maximum dimension d1 of the buffer block 21 along the first direction is the length d1 of the rectangular block. If the shape of the buffer block 21 is a circular block, then the maximum dimension d1 of the buffer block 21 along the first direction is the diameter of the circular block. For other shapes of buffer blocks 21, the maximum dimension d1 of the buffer block 21 along the first direction is the distance between the two points of the buffer block 21 that are farthest apart in the first direction.

[0047] For example, the maximum dimension d1 of the buffer block 21 along the first direction can be 20μm, 50μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, etc. The maximum dimension d1 of the buffer block 21 is in the range of 20μm to 200μm, which is neither too small, which would result in the inability to effectively absorb and disperse the stress of the metal grid lines, thus improving the reliability of the connection between the buffer block 21 and the metal grid lines 11, nor too large, which would result in the shielding of the battery body 3 and the insulation spacing distance being too small.

[0048] In some embodiments, such as Figure 4 As shown, the maximum dimension L1 of the buffer block 21 along the second direction is greater than or equal to 10 μm and less than or equal to 200 μm. Similarly, as... Figure 1 and Figure 4 As shown, when the buffer block 21 is rectangular, and the length direction of the rectangular block is parallel to the second direction, and the width direction is parallel to the first direction, then the maximum dimension L1 of the buffer block 21 along the second direction is the length L1 of the rectangular block. Figure 6 As shown, if the length direction of the rectangular block is parallel to the first direction and the width direction is parallel to the second direction, then the maximum dimension L1 of the buffer block 21 along the second direction is the width of the rectangular block. If the shape of the buffer block 21 is a circular block, then the maximum dimension L1 of the buffer block 21 along the second direction is the diameter of the circular block. For other shapes of buffer blocks, the maximum dimension L1 of the buffer block 21 along the second direction is the distance between the two points of the buffer block 21 that are farthest apart in the second direction.

[0049] For example, the maximum dimension L1 of the buffer block 21 along the second direction can be 10μm, 20μm, 50μm, 80μm, 100μm, 120μm, 140μm, 160μm, 180μm, 200μm, etc. The maximum dimension L1 of the buffer block 21 is within the range of 100μm to 200μm, which is neither too small, thus failing to effectively absorb and disperse the stress of the metal grid lines and improving the reliability of the connection between the buffer block 21 and the metal grid lines 11, nor too large, thus avoiding obstruction of the battery body 3 and excessively small insulation spacing.

[0050] like Figure 4As shown, in some embodiments, in the second direction, the maximum dimension L1 of the buffer block 21 is greater than or equal to the width L2 of the metal grid line 11. With this configuration, the buffer block 21 can fully support the metal grid line 11 in the width direction, resulting in better stress absorption and dispersion, and improving the reliability of the connection between the buffer block 21 and the metal grid line 11.

[0051] In some embodiments, in the second direction, the maximum size L1 of the buffer block 21 is less than or equal to the distance L3 between two adjacent metal grid lines 11, where the distance L3 refers to the distance between the center lines of the two metal grid lines 11. This arrangement ensures that two buffer blocks 21 on adjacent metal grid lines 11 that are close to each other will not contact each other, achieving a good insulation effect.

[0052] like Figure 4 As shown, in some embodiments, in the second direction, the ratio of the maximum size L1 of the buffer block 21 to the width L2 of the metal grid line 11 is 1:1 to 1:1.5. For example, the ratio can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc. In this way, the maximum size L1 of the buffer block 21 is not too small, which would prevent it from fully supporting the metal grid line 11 across its width, thus hindering stress absorption and dispersion; nor is it too large, which would cause it to contact other adjacent buffer blocks 21 in the second direction, affecting the light-shielding and insulation effects.

[0053] like Figure 4 As shown, in some embodiments, the ratio of the maximum dimension L1 of the buffer block 21 along the second direction to the maximum dimension d1 of the buffer block along the first direction is 10:1 to 1:1. For example, the ratio can be 10:1, 8:1, 6:1, 4:1, 2:1, or 1:1. That is, the maximum dimension L1 of the buffer block 21 in the second direction is relatively larger. For rectangular blocks, the arrangement of the rectangular blocks is as follows: Figure 1 , Figure 4 and Figure 5 The structure shown is such that, with this arrangement, more dispersed buffer blocks 21 can be arranged along the extension direction of the metal grid line 11. Under the condition that the overall area ratio of the buffer blocks 21 is the same, the uniformity of stress absorption and dispersion of the metal grid line 11 can be improved.

[0054] like Figure 4As shown, in some embodiments, the spacing d2 between two adjacent buffer blocks 21 along the first direction is 3370μm to 91000μm. For example, the spacing d2 can be 3370μm, 5000μm, 10000μm, 15000μm, 20000μm, 25000μm, 30000μm, 35000μm, 40000μm, 45000μm, 50000μm, 55000μm, 60000μm, 65000μm, 70000μm, 75000μm, 80000μm, 85000μm, 91000μm, etc. The spacing d2 between two adjacent buffer blocks 21 refers to the spacing between the center lines of two adjacent buffer blocks 21. By reasonably setting the spacing of the buffer blocks 21, the stress dispersion and absorption effect of the metal grid line 11 is improved.

[0055] In some embodiments, in the first direction, the ratio of the spacing d2 between two adjacent buffer blocks 21 to the maximum dimension d1 of the buffer block 21 along the first direction is 33:1 to 4550:1. For example, d2 / d1 can be 33:1, 100:1, 500:1, 1000:1, 1500:1, 2000:1, 2500:1, 3000:1, 3500:1, 4000:1, 4550:1, etc. By reasonably setting the spacing and width of the buffer blocks 21, the stress dispersion and absorption effect of the metal grid wire 11 is improved.

[0056] like Figure 2 As shown, in some embodiments, the thickness h2 of the buffer layer 2 is 1μm to 100μm. For example, h2 can be 1μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, etc. The thickness h1 of the metal electrode 1 is 0.1μm to 10μm. For example, h1 can be 0.1μm, 1μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, etc. Therefore, the thickness h2 of the buffer layer 2 needs to be less than the lower limit height of the printing screen. The thickness h2 of the buffer layer 2 is neither too small, which would prevent it from effectively absorbing and dispersing the stress of the metal grid line 11, nor too large, which would result in excessive local support height for the metal grid line 11, causing large height differences at different positions of the metal grid line 11, which is detrimental to the structural strength of the metal grid line 11. This also saves material on the buffer layer 2, reducing costs. The thickness h1 of the metal electrode 1 is within a range that satisfies conductivity requirements while also reducing stress and lowering electrode manufacturing costs.

[0057] In some embodiments, the ratio of the thickness h1 of the metal electrode 1 to the thickness h2 of the buffer layer 2 is 1:80 to 1:5. For example, h1 / h2 can be 1:80, 1:70, 1:60, 1:50, 1:40, 1:30, 1:20, 1:10, 1:5, etc. This satisfies the stress absorption and dispersion requirements of the buffer layer 2 on the metal electrode 1, improves the bonding strength between the metal electrode 1 and the battery body 3 and the buffer layer 2, satisfies the conductivity requirements of the metal electrode 1, and controls the manufacturing cost of the buffer layer 2 and the metal electrode 1.

[0058] In some embodiments, the battery body 3 is a perovskite battery body or a perovskite-silicon tandem battery body. For the perovskite battery body, the functional film layer in contact with the metal electrode 1 is an electron transport layer or a hole transport layer. For example, when the electron transport layer uses C... 60 At that time, because this layer is thin and its structure is very fragile, when it comes into contact with the pure metal electrode 1 deposited on it, the stress on the metal electrode 1 will cause C 60 Layers can delaminate, crack, or even detach from the battery body 3, and the metal electrode 1 can also warp, separate, or detach, affecting the battery's reliability, conductivity, and efficiency. Therefore, by locally inserting a buffer layer 2 between the functional film layer of the perovskite battery body and the metal electrode 1, the stress of the metal electrode 1 can be absorbed and dispersed, solving the stress mismatch problem between the metal electrode 1 and the fragile functional layer in the battery body 3, and improving the bonding reliability between the metal electrode 1 and the film layer of the battery body 3.

[0059] For the perovskite-silicon tandem solar cell body, which is obtained by stacking perovskite solar cells and crystalline silicon solar cells, the perovskite solar cell is the top cell. It also has the same problems as the perovskite solar cell body, which will not be elaborated here. By locally padding a buffer layer 2 between the perovskite functional film layer and the metal electrode 1 in the perovskite-silicon tandem solar cell body, the stress of the metal electrode 1 can be absorbed and dispersed, which solves the stress mismatch problem between the metal electrode 1 and the fragile functional layer in the cell body 3, and improves the bonding reliability between the metal electrode 1 and the film layer of the cell body 3.

[0060] In addition, for other types of solar cells, such as back-contact crystalline silicon cells, TOPCon cells, and HJT cells, when the metal electrode 1 is deposited on the functional layer of the cell body 3, the inconsistency in performance between the metal electrode 1 and the functional layer, such as the coefficient of expansion and material strength, can lead to stress and may cause the same problems as in the above embodiments. Similarly, by locally padding a buffer layer 2 between the functional film layer of the cell body 3 and the metal electrode 1, the stress of the metal electrode 1 can be absorbed and dispersed, thus solving the stress mismatch problem between the metal electrode 1 and the fragile functional layer in the cell body 3 and improving the bonding reliability between the metal electrode 1 and the film layer of the cell body 3.

[0061] The metal electrode fabrication process of the solar cell in this invention is as follows:

[0062] Step 1: According to the required electrode pattern, edit the parameters such as the position and size of the buffer layer to be printed.

[0063] Step 2: Print the buffer layer onto the battery body using a screen printing plate. When the buffer layer is selected from a conductive material layer, it is cured according to its reaction temperature, which is generally 120-180℃ and the curing time is 10-15 minutes. When the buffer layer is selected from an organic material layer, it is cured according to its curing method, such as UV curing or thermal curing.

[0064] Step 3: Place the battery body with the prepared buffer layer in the carrier plate and transfer it to the surface pretreatment chamber.

[0065] Step 4: Pre-treat the surface of the battery substrate using plasma to remove adsorbed impurities and simultaneously provide active sites, promoting the metal interface layer. The process gas can be Ar, N2, or H2.

[0066] Step 5: The processed battery body is covered with a mask film and then transferred to the PVD chamber along with the carrier plate for metal thin film preparation. The PVD method includes, but is not limited to, evaporation, sputtering, and ion plating.

[0067] Step 6: After the coating is completed, the carrier plate is taken out of the PVD chamber and the mask is removed to obtain the metal electrode with the desired metal layer.

[0068] Based on the solar cells described in any of the above embodiments, this invention also provides a photovoltaic module, including a cell string, interconnecting components, and an encapsulation layer. The cell string is formed by electrically connecting a plurality of solar cells as described in any of the above embodiments; the interconnecting components are electrically connected to the solar cells; and the encapsulation layer covers the surface of the cell string. The encapsulation layer may include cover plates and back plates located on both sides of the cell string, as well as encapsulating films and other structures for encapsulation. Because this photovoltaic module uses the solar cells described in any of the above embodiments, it has the same beneficial effects as any of the above embodiments.

[0069] In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0070] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A solar cell, characterized in that, include: The battery body has two opposing sides; Metal electrodes are disposed on the target surface of the battery body; The target surface includes at least one side of the battery body, and the metal electrode is in conductive contact with the battery body; the metal electrode includes a metal layer; A buffer layer is disposed on the target surface; the buffer layer is present between a local area of ​​the metal electrode and the target surface.

2. The solar cell according to claim 1, characterized in that, The buffer layer is selected from a conductive material layer or an organic material layer.

3. The solar cell according to claim 2, characterized in that, The conductive material layer is selected from a metal paste layer; the metal paste layer is selected from one or more combinations of silver paste layer, copper paste layer, aluminum paste layer, and silver-coated copper paste layer.

4. The solar cell according to claim 2, characterized in that, The organic material layer includes one or more combinations of curing adhesive, epoxy adhesive, acrylic, polyurethane, and silicone.

5. The solar cell according to claim 1, characterized in that, The metal electrode includes multiple metal grid lines extending along a first direction, and the multiple metal grid lines are spaced apart along a second direction. The first direction and the second direction intersect, and a buffer layer is provided between a local area of ​​the metal grid lines and the target surface of the battery body.

6. The solar cell according to claim 5, characterized in that, The area of ​​the local region on each metal grid line that contacts the buffer layer accounts for 1% to 15% of the total area of ​​the metal grid line.

7. The solar cell according to claim 5, characterized in that, The buffer layer includes multiple buffer blocks arranged at intervals, with at least one buffer block between each metal grid line and the target surface.

8. The solar cell according to claim 7, characterized in that, The maximum dimension d1 of the buffer block along the first direction is greater than or equal to 20 μm and less than or equal to 200 μm; Alternatively, the maximum dimension L1 of the buffer block along the second direction is greater than or equal to 10 μm and less than or equal to 200 μm.

9. The solar cell according to claim 7, characterized in that, In the second direction, the maximum size L1 of the buffer block is greater than or equal to the width L2 of the metal grid line, and or less than or equal to the spacing between two adjacent metal grid lines.

10. The solar cell according to claim 7, characterized in that, In the second direction, the ratio of the maximum size L1 of the buffer block to the width L2 of the metal grid line is 1:1 to 1:1.

5.

11. The solar cell according to claim 7, characterized in that, The ratio of the maximum dimension L1 of the buffer block along the second direction to the maximum dimension d1 of the buffer block along the first direction is 10:1 to 1:

1.

12. The solar cell according to claim 7, characterized in that, Along the first direction, the distance d2 between two adjacent buffer blocks is 3370μm to 91000μm; and or, along the first direction, the ratio of the distance d2 between two adjacent buffer blocks to the maximum size d1 of the buffer block along the first direction is 33:1 to 4550:

1.

13. The solar cell according to claim 7, characterized in that, When the buffer layer is selected from the conductive material layer, there are 1 to 54 buffer blocks between each metal grid line and the target surface; Alternatively, when the buffer layer is selected from an organic material layer, there are 1 to 17 buffer blocks between each of the metal grid lines and the target surface.

14. The solar cell according to claim 7, characterized in that, The buffer blocks, which are provided for each of the metal grid lines, are evenly distributed along the extension direction of the metal grid lines.

15. The solar cell according to any one of claims 1-14, characterized in that, The thickness h2 of the buffer layer is 1 μm to 100 μm, and the thickness h1 of the metal electrode is 0.1 μm to 10 μm; And / or, the ratio of the thickness h1 of the metal electrode to the thickness h2 of the buffer layer is 1:80 to 1:

5.

16. The solar cell according to any one of claims 1-14, characterized in that, The battery body is a perovskite battery body or a perovskite-silicon tandem battery body.

17. A photovoltaic module, characterized in that, include: A battery string, wherein the battery string is formed by electrically connecting a plurality of solar cells as described in any one of claims 1-16; Interconnector, electrically connected to the solar cell; And an encapsulation layer that covers the surface of the battery string.

Images