Perovskite tandem solar cell with reinforced electrically-conductive adhesive

Abstract

A solar cell according to the present invention comprises: a semiconductor substrate; a plurality of finger electrodes formed on the semiconductor substrate; a bus bar electrically connected to the finger electrodes; and an electrically-conductive adhesive applied in a straight line or dash shape along the bus bar. The electrically-conductive adhesive is formed in a dot shape on a central portion of the semiconductor substrate and is formed in a line shape on an edge portion of the semiconductor substrate. The length of the line is two to four times the maximum length of the dot.

Description

Perovskite tandem solar cell reinforced with electrically conductive adhesive

[0001] The present invention relates to a perovskite tandem solar cell. More specifically, the present invention relates to a perovskite tandem solar cell in which an electrically conductive adhesive is reinforced in the solar cell.

[0002]

[0003] Generally, solar cells include rectangular fingers and busbars printed on the front and back surfaces, and the front and back electrodes of the divided cells are electrically connected to the busbars by means of soldering. Soldering poses an environmental problem because it uses heavy metals such as lead, and it can cause stress on the solar cells, leading to surface damage and warping.

[0004] Meanwhile, technology has been developed to reduce soldering in the manufacturing and assembly of solar cell modules by utilizing electrically conductive adhesives, which are used to attach integrated circuits to substrates or bond electrode tabs to the surface of solar cells. Electrically conductive adhesives are a promising alternative to soldering because they can connect to electrodes at relatively low temperatures. Furthermore, electrically conductive adhesives not only possess electrical conductivity but also provide mechanical bonding strength to the bonding site, thereby stabilizing the solar cell.

[0005] Electrically conductive adhesives are typically applied in a linear form along busbars, although recently they are also being applied in a dashed form. However, the linear form presents problems such as cell obscuration and increased manufacturing costs, while the dashed form leads to an increase in physical defects in solar cells after reliability testing.

[0006] Therefore, it is necessary to design systems that apply electrically conductive adhesives in order to increase solar cell efficiency and reduce physical defects.

[0007] Korean Published Patent Application No. 10-2012-0101627 is disclosed as background technology for the present invention.

[0008]

[0009] The objective of the present invention is to provide a perovskite tandem solar cell reinforced with an electrically conductive adhesive that can improve the manufacturing efficiency of a solar cell by controlling the application location, shape, and size when applying the electrically conductive adhesive to the electrodes of a solar cell, and prevent physical defects from occurring in the central or outer edge portions of the cell by improving the mechanical strength of the cell.

[0010] Another objective of the present invention is to provide a solar cell module with increased photoelectric conversion efficiency and improved durability by applying an electrically conductive adhesive.

[0011] The above and other objectives of the present invention can all be achieved by the present invention described below.

[0012]

[0013] 1. One aspect of the present invention relates to a solar cell.

[0014] Semiconductor substrate;

[0015] A plurality of finger electrodes formed on the semiconductor substrate;

[0016] A busbar electrically connected to the finger electrode; and

[0017] Includes an electrically conductive adhesive in the form of lines and dots along the above busbar;

[0018] The above electrically conductive adhesive has a dot shape at the center of the semiconductor substrate and a line shape at the edge of the semiconductor substrate,

[0019] The above line length is about 2 to 4 times the maximum dot length.

[0020] 2. In the above 1 embodiment, the line and the dot may be formed on the same plane.

[0021] 3. In the above 1 or 2 embodiments, the ratio of the line length to the busbar length may be about 1:10 to 20.

[0022] 4. In any one of the embodiments 1 to 3 above, the busbars may be provided in approximately 2 to 10 units.

[0023] 5. Another aspect of the present invention relates to a perovskite tandem solar cell reinforced with an electrically conductive adhesive.

[0024] The above perovskite tandem solar cell comprises a lower substrate;

[0025] A semiconductor substrate divided into a pattern of electrodes disposed on the lower substrate above;

[0026] Finger electrodes electrically connecting the semiconductor substrate;

[0027] A bus bar having at least one contact point with the finger electrode;

[0028] An interconnection portion formed by applying an electrically conductive adhesive to the above busbar; and

[0029] Includes an upper substrate disposed on the above interconnection portion;

[0030] The above interconnection portion includes a first interconnection portion provided in a line shape at the edge portion of the semiconductor substrate and a second interconnection portion provided in a dot shape at the center portion of the semiconductor substrate.

[0031] The length of the first interconnection part is 2 to 4 times the maximum length of the second interconnection part.

[0032] 6. In the above 5 embodiments, a lower encapsulating material disposed between the lower substrate and the semiconductor substrate and an upper encapsulating material disposed between the interconnection portion and the upper substrate may be further included.

[0033] 7. In the above 5 or 6 embodiments, a side sealing material may be further included to be disposed between the lower substrate and the upper substrate to seal the space between the lower substrate and the upper substrate.

[0034] 8. In any one of the embodiments 5 to 7 above, the semiconductor substrate may include one or more of a silicon layer, a perovskite layer, an organic layer, and a dye-sensitized metal oxide layer as a photoactive layer.

[0035] 9. In any one of the embodiments 5 to 8 above, the finger electrode may further include a wire connecting the divided semiconductor substrates in series.

[0036] 10. In any one of the embodiments 5 to 9 above, the wire may electrically contact the busbar by clustering.

[0037] 11. In any one of the embodiments 5 to 10 above, the length and width of the first interconnection part and the second interconnection part may be determined according to the following mathematical formulas 1 and 2.

[0038] [Mathematical Formula 1]

[0039] H1 > H2

[0040] [Mathematical Formula 2]

[0041] W1 ≤ W2

[0042] In the above mathematical formulas 1 and 2, H1 is the length of the first interconnection extending along the busbar, H2 is the length of the second interconnection, W1 is the width of the first interconnection, and W2 is the width of the second interconnection.

[0043] 12. In any one of the embodiments of 5 to 11 above, H1 may be about 9 to 18 mm, H2 may be about 2 to 4 mm, W1 may be 1 to 1.5 mm, and W2 may be about 1 to 2 mm.

[0044] 13. In any one of the embodiments 5 to 12 above, the amount of electrically conductive adhesive applied per unit area is approximately 5.0 × 10 -4 Up to 1.0 × 10 -3 g / cm 2 It could be.

[0045] 14. In any one of the above 5 to 13 embodiments, the peel rate after a solar cell reliability test according to IEC 61215 may be about 0.9 or less.

[0046] 15. In any one of the embodiments 5 to 14 above, physical defects may not occur at the edge of the cell after a solar cell reliability test according to IEC 61215.

[0047] 16. In any one of the embodiments of 5 to 15 above, a lower interconnection portion may be further included, which is disposed on the lower part of the semiconductor substrate and disposed in the same form as the interconnection portion.

[0048] 17. In any one of the embodiments of 5 to 16 above, a junction box may be further included in which one end of the busbar and the finger electrode are electrically connected.

[0049] 18. In any one of the embodiments of 5 to 17 above, one end of the busbar and the finger electrode may further include a strip or busbar ribbon electrically connected.

[0050] 19. Another aspect of the present invention provides a solar cell module comprising a perovskite tandem solar cell reinforced with the electrically conductive adhesive.

[0051]

[0052] The solar cell reinforced with an electrically conductive adhesive according to the present invention can solve environmental problems or increased manufacturing costs associated with soldering by applying an electrically conductive adhesive to the electrodes of the cell.

[0053] By controlling the application location, shape, and size of the electrically conductive adhesive, the reduction in power conversion efficiency due to cell occlusion is prevented. Since the electrically conductive adhesive can be applied through a simple printing process, not only is cell manufacturing efficiency improved, but physical defects in the center and edge areas of the cell can also be effectively prevented even after solar cell reliability tests such as IEC 61215 by providing mechanical bonding strength at the application site of the electrically conductive adhesive.

[0054]

[0055] FIG. 1 is a plan view of a perovskite tandem solar cell reinforced with an electrically conductive adhesive according to one embodiment of the present invention.

[0056] Figure 2 is a cross-sectional view along the line I-II' of Figure 1.

[0057] FIG. 3 is a plan view of a perovskite tandem solar cell reinforced with an electrically conductive adhesive according to another embodiment of the present invention.

[0058] Figure 4 is a surface photograph of a solar cell after a reliability test of an embodiment and a comparative example of the present invention.

[0059] Figure 5 is a graph showing the total coating amount per ECA area according to the ECA application design of the embodiments and comparative examples of the present invention.

[0060]

[0061] The present invention will be described in more detail below with reference to the attached drawings. However, the following drawings are provided merely to aid in understanding the present invention, and the present invention is not limited by the drawings. Furthermore, the shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings are exemplary, and the present invention is not limited to the depicted details.

[0062] Throughout the specification, the same reference numerals refer to the same components. Additionally, in describing the present invention, detailed descriptions of related prior art are omitted if it is determined that such detailed descriptions would unnecessarily obscure the essence of the invention.

[0063] Where terms such as 'includes,' 'have,' and 'consists of' are used in this specification, other parts may be added unless 'only' is used. Where a component is expressed in the singular, it includes cases where it is in the plural unless specifically stated otherwise.

[0064] In interpreting the components, they are interpreted to include a margin of error even in the absence of a separate explicit statement.

[0065] In this specification, "a to b" indicating a numerical range is defined as "≥a and ≤b".

[0066] In this specification, all numerical ranges include a 95% standard error range.

[0067] In this specification, 'line' is defined as having an aspect ratio (maximum length / width) in the range of about 1 / 9 to 1 / 0 / 2, and 'dot' is defined as having an aspect ratio (maximum length / width) in the range of about 2 / 2 to 4 / 2. The shape of the dot may be circular, square, triangular, rod-shaped, etc., but is not necessarily limited thereto.

[0068] One aspect of the present invention relates to a solar cell in which the design of the application area of ​​an electric conductive adhesive (hereinafter 'ECA') on the front electrode and the rear electrode is modified.

[0069] Referring to FIGS. 1 to 3, the solar cell includes a semiconductor substrate (200), a finger electrode (210), a bus bar (300), and an ECA.

[0070] The above semiconductor substrate (200) can generate and transmit charge carriers by sunlight.

[0071] The above semiconductor substrate (200) is not particularly limited as long as it includes a light-absorbing layer, and may be, for example, one or more of a silicon layer, amorphous silicon, a perovskite layer, CdS / CdTe, an organic layer, or a dye-sensitized metal oxide.

[0072] The plurality of finger electrodes (210) are formed on the semiconductor substrate (200).

[0073] The finger electrode (210) can be formed by metallizing the semiconductor substrate (200) on one side of the semiconductor substrate (200) by screen printing, for example, by forming an n-type emitter on a p-type silicon wafer to manufacture the semiconductor substrate (200) and then screen printing an Ag paste, and in order to reduce resistance, a part of the electrode may be opened with a laser or the like.

[0074] The above bus bar (300) is electrically connected to the finger electrode (210) formed as a grid and is a rod-shaped electrode that intersects the finger electrode (210).

[0075] The above bus bar (300) can collect charge carriers transmitted from the finger electrode (210) and transfer them to the outside.

[0076] In one embodiment, the busbar (300) may be provided in 2 to 10 units.

[0077] The above busbar (300) can be increased according to the area of ​​the cell, and typically, 2 to 3 busbars (300) are provided per cell to account for increased resistance. However, since resistance can be reduced when the ECA is applied along the busbar (300), the design can be made more flexible when forming the electrode, and the number of busbars (300) can be increased from 2 to 10. However, it is preferable that the busbar (300) be determined according to the wafer size constituting the semiconductor substrate (200).

[0078] The finger electrode (210) and bus bar (300) above constitute the metal electrode of the solar cell.

[0079] The finger electrode (210) and bus bar (300) do not transmit sunlight but reflect it, which can increase shading loss that lowers solar cell efficiency.

[0080] It is important to increase the opening ratio by reducing the line width of the finger electrode (210) and bus bar (300), but if the electrode width is reduced too much, the resistance of the electrode itself increases and electrical loss may occur.

[0081] The above ECA is provided in the form of lines and dots along the busbar (300).

[0082] The above ECA can replace solder as an interconnecting material. The ECA provides mechanical bonding between two surfaces and conducts electricity. Specifically, the ECA can be manufactured from a polymer resin filled with an electrically conductive metal filler, wherein the resin provides mechanical properties between two substrates, while the electrically conductive filler provides electrical interconnection.

[0083] The above ECA is applied to the bus bar (300) to improve electrical conductivity between the finger electrode (210) and the bus bar (300), reduce shading loss due to line width reduction of the finger electrode (210) and the bus bar (300), and reduce the increase in electrode resistance.

[0084] The above ECA is applied to the busbar (300) to not only improve the mechanical strength of the busbar (300) but also effectively prevent physical defects of the semiconductor substrate (200).

[0085] The above ECA can be applied in the form of a dot having a certain spacing (430) at the center of the semiconductor substrate (200) and in the form of a line at the edge.

[0086] When the ECA is applied in a line shape, shading loss increases excessively, and when it is in a dash shape, physical defects are very likely to occur at the edge portion of the semiconductor substrate (200). When the ECA is applied in a line shape at the edge portion of the semiconductor substrate (200) to increase the bonding strength with the bus bar (300) and reduce the occurrence of physical defects, and when it is applied in a dot shape with a certain spacing distance (430) at the center portion, the amount of ECA used can be reduced to increase the solar cell manufacturing efficiency, and shading loss can be reduced to effectively improve the photoelectric conversion efficiency (EQE) of the solar cell.

[0087] The length of the above line may be about 2 to 4 times the maximum length of the above dot (e.g., 2, 3, or 4 times).

[0088] The length of the line is extended to the above range, so that physical defects can be effectively prevented at the outermost edge of the cell, specifically at the edge portion of the semiconductor substrate (200).

[0089] In one embodiment, the line and the dot may be formed on the same plane.

[0090] The above lines and dots can be formed on the busbar and arranged on the same plane.

[0091] In one embodiment, the ratio of the line length to the busbar length may be about 1:10 to 20 (e.g., 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19, or 1:20).

[0092] If limited to the above range, an increase in shading loss due to line length can be prevented.

[0093] Another aspect of the present invention relates to a perovskite tandem solar cell (1000) reinforced with an electrically conductive adhesive (400).

[0094] The above perovskite tandem solar cell (1000) includes a lower substrate (110), a semiconductor substrate (200), a finger electrode (210), a bus bar (300), an interconnection part (400), and an upper substrate (120).

[0095] The lower substrate (110) may be a glass substrate if it has a superstrate structure, and may be a flexible foil made of stainless steel, polyethylene naphthalate (PEN), and polyimide if it has a substrate structure.

[0096] The perovskite tandem solar cell (1000) according to the present invention includes a PIN structure and an NIP structure, and the structure can be selected according to the purpose of solar power generation, and the lower substrate (110) and the upper substrate (120) can be classified into single-sided light receiving type or double-sided light receiving type.

[0097] The lower substrate (110) above can provide a space for a semiconductor substrate (200) to be placed.

[0098] The lower substrate (110) can be combined with a corresponding upper substrate (120) to seal the semiconductor substrate (200).

[0099] It may further include a lower encapsulating material (520) disposed between the lower substrate (110) and the semiconductor substrate (200), and an upper encapsulating material (510) disposed between the interconnection part (400) and the upper substrate (120).

[0100] The lower sealing material (520) and the upper sealing material (510) may be a silicone sealant, or one or more of a hot melt adhesive, epoxy, and double-sided tape, and are not particularly limited as long as they have a non-flowing viscosity when applied to the lower substrate (110) and the upper substrate (120) and can seal the lower substrate (110) and the upper substrate (120).

[0101] The lower sealing material (520) and the upper sealing material (510) are provided so that the semiconductor substrate (200) can be effectively protected from moisture or external contaminants.

[0102] It may further include a side sealing material (600) disposed between the lower substrate (110) and the upper substrate (120) to seal the space between the lower substrate (110) and the upper substrate (120).

[0103] When the semiconductor substrate (200) is provided between the lower substrate (110) and the upper substrate (120), a side sealing material (600) that seals the space between the lower substrate (110) and the upper substrate (120) may be further included. The side sealing material (600) is not particularly limited as long as it can adjust the gap between the lower substrate (110) and the upper substrate (120) and maintain airtightness. For example, the side sealing material (600) may be provided with butyl rubber, which is highly desirable as it is soluble and can prevent the permeation of moisture and gas.

[0104] The semiconductor substrate (200) is divided into a pattern of electrodes disposed on the lower substrate (110).

[0105] The semiconductor substrate (200) can generate charge carriers through light absorption, and for example, the semiconductor substrate (200) may include one or more of a silicon layer, a perovskite layer, an organic layer, and a dye-sensitized metal oxide layer as photoactive layers, and preferably, it may be a solar cell of a tandem structure including a photoactive layer in which a silicon layer and a perovskite layer are stacked.

[0106] The above semiconductor substrate (200) is identical to the configuration described above, and a repeated explanation will be omitted.

[0107] The finger electrode (210) electrically connects the semiconductor substrate (200).

[0108] The finger electrode (210) is formed on the semiconductor substrate (200) and can be formed by metallizing the surface of the semiconductor substrate (200).

[0109] The finger electrode (210) can transport charge carriers formed on the semiconductor substrate (200) and deliver them to the bus bar (300).

[0110] The finger electrode (210) can be divided to reduce resistance, for example, by using a laser to divide it into strips of a certain length to form an open surface in which some or all of it is open.

[0111] Referring to FIG. 3, the finger electrode (210) may further include a wire (800) that connects the divided semiconductor substrate (200) in series.

[0112] One end of the wire (800) can be clustered to make electrical contact with the bus bar (300).

[0113] When the finger electrode (210) is divided to form an open surface, one of the finger electrodes (210) can be connected in series with an adjacent finger electrode (210) through a wire (800), and the wire (800) can be electrically connected to the bus bar (300) by being bundled together.

[0114] The above bus bar (300) has at least one contact point with the finger electrode (210).

[0115] The above bus bar (300) is electrically connected to the finger electrode (210) and can collect charge carriers transferred from the finger electrode (210) and transfer them to an external circuit.

[0116] The above interconnection part (400) is formed by applying ECA on the bus bar (300).

[0117] The above interconnection portion (400) may be provided along the bus bar (300), and specifically, may be formed by applying ECA on the bus bar (300).

[0118] The above interconnection portion (400) includes a first interconnection portion (410) provided in a line shape at the edge portion of the semiconductor substrate (200) and a second interconnection portion (420) provided in a dot shape having a certain spacing distance (430) at the center portion of the semiconductor substrate (200).

[0119] The above interconnection portion (400) incorporates an ECA application design provided in the form of lines and dots to reduce shading loss and improve photoelectric conversion efficiency, and can effectively prevent physical defects of the solar cell by improving mechanical bonding strength between the upper substrate (120) or the lower substrate (110). Specifically, the occurrence of defects can be effectively prevented by applying a line shape at the edge portion of the semiconductor substrate (200), where many physical defects occur after reliability testing, thereby improving mechanical bonding strength, and by applying dots in a dashed shape with a certain spacing at the center portion, the amount of ECA used can be reduced and shading loss can be reduced, thereby providing an optimal ECA application design that can increase photoelectric power conversion efficiency.

[0120] The length of the first interconnection part (410) may be 2 to 10 times the maximum length of the second interconnection part (420).

[0121] If the length of the first interconnection part (410) is longer than the second interconnection part (420) within the above range, the occurrence of physical defects at the edge of the semiconductor substrate (200) can be suppressed more effectively.

[0122] In one embodiment, the length and width of the first interconnection part (410) and the second interconnection part (420) may be determined according to the following mathematical formulas 1 and 2.

[0123] [Mathematical Formula 1]

[0124] H1 > H2

[0125] [Mathematical Formula 2]

[0126] W1 ≤ W2

[0127] In the above mathematical formulas 1 and 2, H1 is the length of the first interconnection part (410) extending along the busbar, H2 is the length of the second interconnection part (420), W1 is the width of the first interconnection part (410), and W2 is the width of the second interconnection part (420).

[0128] According to the above mathematical formula 1, the length (Height) of the first interconnection part (410) arranged along the bus bar (300) is applied longer than that of the second interconnection part (420) to reinforce the edge portion of the semiconductor substrate (200) where many physical defects occur in the semiconductor substrate (200), thereby improving the durability of the solar cell.

[0129] According to the above mathematical formula 2, if the width of the second interconnection part (420) is greater than or equal to the width of the first interconnection part (410), mutual contact with the bus bar (300) at the coating area is increased, and the finger electrode (210) is stabilized, thereby effectively increasing the mechanical strength of the entire solar cell.

[0130] According to the above mathematical formulas 1 and 2, the length and width of the interconnection portion (400) are adjusted to reduce the amount of ECA used, thereby improving the solar cell manufacturing efficiency, and the photoelectric conversion efficiency (PCE) can be improved by reducing shading loss through an increased open area.

[0131] In one embodiment, H1 is about 9 to 18 mm (e.g., 9, 10, 11, 12, 13, 14, 15, 16, 17, or 18 mm), H2 is about 2 to 4 mm (e.g., 2, 3, or 4 mm), W1 is about 1 to 1.5 mm (e.g., 1, 1.1, 1.2, 1.3, 1.4, or 1.5 mm), preferably about 1.1 mm to 1.3 mm, and W2 is about 1 to 2 mm (e.g., 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, or 2.0 mm), preferably about 1.5 to 2 mm. In cases where mathematical formulas 1 and 2 are satisfied within the above range, an ECA application design in which ECA is applied in the form of lines and dots is possible, and not only can the manufacturing efficiency of the solar cell be improved by reducing the amount of ECA applied, but the occurrence of physical defects in the solar cell can also be effectively suppressed.

[0132] In one embodiment, the amount of electrically conductive adhesive (ECA) applied per unit area is approximately 5.0 × 10 -4 Up to 1.0 × 10 -3 g / cm 2 (e.g., 0.0005, 0.0006, 0.0007, 0.0008, 0.0009, or 0.0010 g / cm³ 2 It can be.

[0133] The above ECA can be sufficiently applied in the form of straight lines or dots within the above range, and while reducing the amount of ECA applied, the degree of freedom in the design of ECA application can be improved and physical defects of the solar cell can also be reduced.

[0134] The upper substrate (120) is placed on the interconnection portion (400).

[0135] The upper substrate (120) may be placed on the interconnection part (400) and may be supported and fixed by the interconnection part (400).

[0136] Specifically, the interconnection portion (400) is provided as an ECA and is provided in a linear form at the edge portion of the semiconductor substrate (200), thereby increasing the mechanical bonding force and reducing lifting or physical defects between the upper substrate (120) and the bus bar (300).

[0137] In one embodiment, a lower interconnection part (not shown) may be further included, which is disposed on the lower part of the semiconductor substrate (200) and is disposed in the same form as the interconnection part.

[0138] The above interconnection portion (400) is also applied to the lower part of the semiconductor substrate (200) and is provided in a line shape and a dash shape (not shown), identical to the interconnection portion (400) placed on the upper part, thereby stabilizing the semiconductor substrate (200) and reducing physical defects of the cell.

[0139] In one embodiment, a junction box (700) may be further included in which one end of the bus bar (300) and the finger electrode (210) are electrically connected.

[0140] The above junction box (700) accommodates a connection terminal to which a wire (800) or cable extending from the bus bar (300) and finger electrode (210) is connected, and prevents leakage of current and can supply electricity by connecting to an external circuit.

[0141] In one embodiment, one end of the busbar (300) and the finger electrode (210) may further include a strip or busbar ribbon (not shown) electrically connected.

[0142] The above strip or busbar ribbon can connect the finger electrode and one end of the busbar to effectively transfer the charge of the finger electrode, thereby improving photoelectric conversion efficiency.

[0143] In one embodiment, the peel rate after a solar cell reliability test according to IEC 61215 may be about 0.9 or less (e.g., 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9).

[0144] The above IEC 61215 tests the degree of degradation when a solar cell module is exposed to a temperature change of approximately -40 to 85°C. According to IEC 61215 certification, this corresponds to MQT. 11 (Module Quality Test). It measures the degree of degradation by exposing the solar cell module to a temperature change of approximately -40 to 85°C without humidity control. The peeling rate is measured by comparing the area where the solar cell is broken, cracked, discolored, or where foam, peeling, yellowing, or browning occurs on the front surface of the module to the total area of ​​the cell.

[0145] After the above reliability test, the peeling rate is reduced to within the above range, which can significantly improve the durability of the solar cell according to the ECA application design.

[0146] In one embodiment, physical defects may not occur at the edge of the cell after a solar cell reliability test according to IEC 61215.

[0147] According to the ECA application design with the above-mentioned line shape and dash shape, physical defects do not occur at the edge of the solar cell, and deformation such as bending in the semiconductor substrate (200) can also be prevented.

[0148] Accordingly, a perovskite tandem solar cell (1000) reinforced with an electrically conductive adhesive according to one embodiment of the present invention is designed to prevent physical defects from occurring at the edges of a semiconductor substrate (200) by arranging interconnection portions (400) in the form of straight lines and dots when applying ECA to the front or rear electrodes, and at the center of the semiconductor substrate (200), by forming mutual contact points that are spaced evenly apart in the form of continuous dashes of dots, thereby increasing mechanical bonding strength and improving the durability of the solar cell, as well as minimizing shading loss and increasing power conversion efficiency.

[0149] Another aspect of the present invention provides a solar cell module comprising a perovskite tandem solar cell reinforced with the electrically conductive adhesive (400).

[0150] A perovskite tandem solar cell reinforced with the above electrically conductive adhesive (400) can form a cell, and a solar cell module can be manufactured by connecting multiple cells.

[0151] The above solar cell modules can be designed with an appropriate capacity depending on the application goal, and it is also possible to configure a large-capacity solar cell array by connecting these modules in series or parallel circuits.

[0152]

[0153] Hereinafter, preferred embodiments are presented to aid in understanding the present invention; however, the following embodiments are merely illustrative of the invention and the scope of the invention is not limited to the following embodiments.

[0154]

[0155] Example 1

[0156] A glass substrate was selected as the lower substrate, and a semiconductor substrate including a silicon layer and a perovskite layer was placed on it. Finger electrodes were formed by screen printing Ag paste, and then bus bars were printed to make electrical contact with each other. ECA was applied along the bus bars, forming a line shape of approximately 9 mm × 1 mm in length at the edge of the semiconductor substrate, and dots of approximately 2 mm × 2 mm were applied at regular intervals in a dash shape at the center.

[0157] A glass substrate was placed as the upper substrate, and the space between the lower substrate and the upper substrate was sealed using lower, upper, and side encapsulation materials to complete the solar cell.

[0158]

[0159] Comparative Example 1

[0160] A solar cell was completed by applying ECA in a continuous line form from top to bottom to the same semiconductor substrate as in Example 1.

[0161]

[0162] Comparative Example 2

[0163] ECA was applied to the same semiconductor substrate as in Example 1 in a line form only, and coated in a pattern of repeating lines approximately 9 mm in length.

[0164]

[0165] Comparative Example 3

[0166] ECA was applied to a semiconductor substrate identical to Example 1 in the form of dots having a length and width of approximately 3.6 mm × 1 mm.

[0167]

[0168] Comparative Example 4

[0169] A solar cell was completed in the same manner as in Example 1, except that the line length was applied so that it was approximately 16.2 mm when designing the ECA application in Example 1.

[0170]

[0171] Experimental Example 1. Deterioration Test

[0172] After the reliability test, the degree of degradation of the solar cell was verified according to the IEC 61215 standard.

[0173] The IEC 61215 test was conducted by performing a temperature change test of approximately -40 to 85 ℃ corresponding to MQT 11 (Module Quality Test).

[0174] IEC 61215 is a standard for testing the degree of degradation induced when a solar cell module is exposed to a temperature change of approximately -40 to 85°C. Solar cell cells according to the examples and comparative examples were exposed to a temperature change of approximately -40 to 85°C and a condition without humidity control for approximately 200 cycles, after which the degree of degradation was measured.

[0175] Figure 4 is a surface photograph of a solar cell after a reliability test of an embodiment and a comparative example of the present invention.

[0176] Referring to Fig. 4, it was confirmed that in Comparative Example 1, physical defects appear along the ECA inside the cell, and physical defects such as interlayer delamination also appear at the cell edges.

[0177] In Comparative Example 2, it was confirmed that physical defects appeared along the ECA inside the cell and also at the cell edges, and in Comparative Example 3, it was confirmed that physical defects did not appear along the ECA inside the cell but appeared at the cell edges.

[0178] In contrast, it was confirmed that physical defects appearing in the solar cell in Examples 1 and 2 did not occur compared to the Comparative Example.

[0179]

[0180] Experimental Example 2.

[0181] The amount of ECA applied according to the ECA application design was verified, and the peeling area and the resulting peeling rate were confirmed.

[0182] Figure 5 is a graph showing the total coating amount per ECA area according to the ECA application design of the embodiments and comparative examples of the present invention.

[0183] Example 1 (Design D) Comparative Example 1 (Design A) Comparative Example 2 (Design B) Comparative Example 3 (Design E) Comparative Example 4 (Design C) Total Coverage (g) 0.1675 0.60600 0.33800 0.14890 0.2791 Total Coverage per Area (g / cm²) 2 )0.0005070.0018360.0010240.0004510.000845 Delamination area(m 2 Peeling Rate(%)0.3615.291.620.700.81

[0184] In Table 1 above, the peeling rate (%) is an indicator of physical defects in solar cells and is the ratio of the peeled area to the total active area within the solar cell according to the following mathematical formula 3.

[0185] [Mathematical Formula 3]

[0186] Delamination Rate (%) = [(Delaminated Area / Total Solar Cell Area) x 100]

[0187] Referring to Table 1 and Figure 5, it was confirmed that the peeling rate after reliability testing is the lowest when the ECA application design according to Example 1 is used, and the amount of ECA applied can also be reduced by about 72% compared to Comparative Example 1, which is a conventional ECA application design, thereby greatly increasing manufacturing efficiency.

[0188] In the case of Example 1, it was confirmed that the peel rate was improved by about 97% compared to Comparative Example 1, by about 77% compared to Comparative Example 2, and by more than 48% compared to Comparative Example 3.

[0189] Meanwhile, in Example 1, the ECA application amount was approximately 0.000507 g / cm² 2 It was confirmed that physical defects appearing after reliability testing were very effectively suppressed through a mixed design of line and dot patterns, and the ECA coating amount was approximately 0.000507 g / cm²2 It was confirmed that as it increased, the occurrence of physical defects increased slightly but was less than about 1%.

[0190] Therefore, in Example 1, the ECA was set in a linear form at the cell edge with a vertical dimension of approximately 9 mm, and in a dot form at the cell center with a vertical dimension of approximately 4 mm or less and a horizontal dimension of approximately 2 mm or less, and the ECA application amount range was set to approximately 0.0005 g / cm² 2 Above approximately 0.001 g / cm³ 2 It was confirmed that setting it below is the optimal condition for maintaining a low peel rate.

[0191] A perovskite tandem solar cell reinforced with an electrically conductive adhesive according to one embodiment of the present invention can provide a solar cell that incorporates an optimal ECA application design, wherein the ECA is applied in a dashed form in which lines and dots are continuously arranged along the bath when the ECA application design is applied, but the application form is varied according to the part of the cell and the amount of ECA applied is reduced, thereby increasing the manufacturing efficiency of the solar cell while reducing the peeling rate and preventing defects in the solar cell.

[0192]

[0193] The present invention has been described above with reference to embodiments. Those skilled in the art will understand that the present invention may be embodied in modified forms without departing from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the invention is defined by the claims, not by the foregoing description, and all variations within the scope of equivalents should be interpreted as being included in the invention.

Claims

1. Semiconductor substrate; A plurality of finger electrodes formed on the semiconductor substrate; A busbar electrically connected to the finger electrode; and Includes an electrically conductive adhesive in the form of lines and dots along the above busbar; The above electrically conductive adhesive has a dot shape at the center of the semiconductor substrate and a line shape at the edge of the semiconductor substrate, The above line length is approximately 2 to 4 times the maximum dot length, Solar cell.

2. A solar cell according to claim 1, wherein the line and the dot are formed on the same plane.

3. A solar cell according to claim 1, wherein the ratio of the line length to the busbar length is approximately 1:10 to 20.

4. A solar cell according to claim 1, wherein the busbars are provided in approximately 2 to 10 units.

5. Lower substrate; A semiconductor substrate divided into a pattern of electrodes disposed on the lower substrate above; Finger electrodes electrically connecting the semiconductor substrate; A bus bar having at least one contact point with the finger electrode; An interconnection portion formed by applying an electrically conductive adhesive to the above busbar; and Includes an upper substrate disposed on the above interconnection portion; The above interconnection portion includes a first interconnection portion provided in a line shape at the edge portion of the semiconductor substrate and a second interconnection portion provided in a dot shape at the center portion of the semiconductor substrate. The length of the first interconnection is approximately 2 to 4 times the maximum length of the second interconnection, Perovskite tandem solar cell reinforced with electrically conductive adhesive.

6. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, further comprising a lower encapsulating material disposed between the lower substrate and the semiconductor substrate and an upper encapsulating material disposed between the interconnection portion and the upper substrate.

7. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, further comprising a side encapsulating material disposed between the lower substrate and the upper substrate to seal the space between the lower substrate and the upper substrate.

8. In claim 5, the semiconductor substrate comprises one or more of a silicon layer, a perovskite layer, an organic layer, and a dye-sensitized metal oxide layer as a photoactive layer, and is a perovskite tandem solar cell reinforced with an electrically conductive adhesive.

9. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, wherein the finger electrode further comprises a wire connecting divided semiconductor substrates in series.

10. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 9, wherein the wire is electrically in contact with the busbar by clustering.

11. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, wherein the length and width of the first interconnection and the second interconnection are determined according to the following mathematical formulas 1 and 2: [Mathematical Formula 1] H1 > H2 [Mathematical Formula 2] W1 ≤ W2 In the above mathematical formulas 1 and 2, H1 is the length of the first interconnection extending along the busbar, H2 is the length of the second interconnection, W1 is the width of the first interconnection, and W2 is the width of the second interconnection.

12. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 11, wherein H1 is about 9 to 18 mm, H2 is about 2 to 4 mm, W1 is about 1 to 1.5 mm, and W2 is about 1 to 2 mm.

13. In paragraph 5, the amount of electrically conductive adhesive applied per unit area is approximately 5.0 × 10 -4 Up to 1.0 × 10 -3 g / cm 2 A perovskite tandem solar cell reinforced with an electrically conductive adhesive.

14. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, wherein the peel rate after solar cell reliability testing according to IEC 61215 is about 0.9 or less.

15. An electrically conductive adhesive-reinforced perovskite tandem solar cell in which no physical defects occur at the edge of the cell after a solar cell reliability test according to IEC 61215, as per claim 5.

16. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, further comprising a lower interconnection portion disposed on the lower part of the semiconductor substrate and disposed in the same form as the interconnection portion.

17. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, further comprising a junction box in which one end of the busbar and the finger electrode are electrically connected.

18. An electrically conductive adhesive-reinforced perovskite tandem solar cell according to claim 5, further comprising a strip or busbar ribbon electrically connected to one end of the busbar and the finger electrode.

19. A perovskite tandem solar cell reinforced with an electrically conductive adhesive according to paragraph 5, Solar cell module.

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