Back contact battery piece, printing steel plate and photovoltaic module

Abstract

The invention provides a back contact battery piece, a printing steel plate and a photovoltaic module, and relates to the technical field of photovoltaics. The back contact battery piece comprises a battery body which comprises a first surface and a second surface which are opposite to each other along the thickness direction of the battery body; the plurality of current collection electrodes are arranged on the first surface of the battery body and extend along the first direction; the plurality of current collection electrodes comprise a first current collection electrode and a second current collection electrode which are sequentially distributed along a second direction; the first direction intersects with the second direction; the insulating block is positioned in a local area of one side, far away from the battery body, of the collector electrode continuously arranged along the first direction; in the same collector electrode, the height of at least the first part covered by the insulating block is H1, the height of at least the second part not covered by the insulating block is H2, and H1 is smaller than H2. In the same current collection electrode, the height H1 of at least the first part which is covered by the insulating block and has the short circuit risk is relatively low, so that the short circuit risk is obviously reduced.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a back contact solar cell, a printed steel plate, and a photovoltaic module. Background Technology

[0002] Back-contact solar cells, due to their structure without grid lines on the light-facing side, can make full use of sunlight, resulting in higher efficiency. Furthermore, the absence of grid lines on the light-facing side makes the module appearance more aesthetically pleasing, thus offering broad application prospects.

[0003] However, in back-contact solar cells, electrode structures such as current collectors of different polarities are all located on the backlight side, which poses a high risk of short circuits. Summary of the Invention

[0004] This application provides a back-contact solar cell, a printed steel plate, and a photovoltaic module, aiming to solve the problem of high short-circuit risk in existing back-contact solar cells.

[0005] A first aspect of this application provides a back contact battery cell, comprising: The battery body, along its thickness direction, includes opposing first and second surfaces; A plurality of current collector electrodes are disposed on a first surface of the battery body and extend along a first direction; the plurality of current collector electrodes include: a first current collector electrode and a second current collector electrode, which are sequentially distributed along a second direction; the first direction intersects the second direction; An insulating block is located in a local area on the side away from the battery body of a current collector electrode that is continuously arranged along a first direction. In the same current collector electrode: the height of at least the first part covered by the insulating block is H1, and the height of at least the second part not covered by the insulating block is H2, where H1 < H2.

[0006] In this application, it is difficult to completely avoid the formation of printed spikes on the printed current collector electrode. The penetration or proximity of these spikes to the insulating block is a major cause of short circuits in back-contact solar cells. Within the same current collector electrode: the portion covered by the insulating block typically contains conductive structures such as interconnects and busbars that are electrically connected to current collector electrodes of the opposite polarity. If the printed spikes in this portion penetrate the insulating block, they will connect to the interconnects and busbars, causing a short circuit. If the printed spikes in this portion are close to the insulating block, the insulating block above the spikes is thinner and will appear black during EL testing of the solar cell, also posing a short circuit risk. The portion not covered by the insulating block generally does not contain conductive structures such as interconnects or busbars that are electrically connected to current collector electrodes of the opposite polarity, thus posing virtually no short circuit risk. In this application, in the same current collector electrode, the height H1 of at least the first part covered by the insulating block and posing a short-circuit risk is less than the height H2 of at least the second part not covered by the insulating block and posing virtually no short-circuit risk. This can significantly reduce the height of the printed protrusions in the first part covered by the insulating block and posing a short-circuit risk in the same current collector electrode, thereby significantly reducing the short-circuit risk caused by the printed protrusions in the first part of the same current collector electrode penetrating or being near the insulating block, thus improving battery performance and reliability.

[0007] Furthermore, compared to the intermittently arranged current collector electrodes along the first direction, the continuously arranged current collector electrodes in this application, without any disconnected regions, result in a wider carrier or current collection area, thus improving battery performance. Simultaneously, the second portion, with its relatively large height H2 and virtually no short-circuit risk, achieves excellent current collection and transmission capabilities.

[0008] Meanwhile, in the back-contact solar cell, the presence of the insulating block locally increases the height, while the area without the insulating block has a lower height. This height difference becomes more pronounced after the busbar or interconnect (such as solder pads) is further placed above the insulating block, leading to increased height fluctuations on the cell surface. On the one hand, the height difference hinders the formation of an effective connection between the back-contact solar cell and external interconnects (such as solder ribbons), easily causing poor contact between the busbar or interconnect (PAD) and the interconnect (solder ribbon); on the other hand, the height difference makes the back-contact solar cell prone to microcracks during the lamination process, affecting process yield. Therefore, in this application, the height of the current collector electrode below the insulating block is reduced, which can also correspondingly reduce the overall height difference or fluctuation, increasing the reliability of subsequent module-end stringing and lamination, and forming an effective connection.

[0009] In summary, this application balances current harvesting efficiency and short-circuit risk, not only reducing short-circuit risk but also improving current harvesting efficiency, thereby enhancing battery performance and reliability.

[0010] In some embodiments, in the same current collector electrode: along the second direction, the width of at least a first portion covered by the insulating block is W1, and the width of at least a second portion not covered by the insulating block is W2, where W1 < W2.

[0011] In some embodiments, the difference between W2 and W1 is greater than or equal to 1 μm and less than or equal to 50 μm, and / or the ratio of W2 to W1 is 1.1 to 3.

[0012] In some embodiments, in the same current collector electrode: the aspect ratio of the second portion is greater than the aspect ratio of the first portion.

[0013] In some embodiments, the height of the insulating block is H3, where H3 > H1; The difference between H3 and H1 is greater than or equal to 5 μm, and / or the ratio of H3 to H1 is between 1.2 and 15.

[0014] In some embodiments, the ratio of H2 to H1 is 1.1 to 5; and / or, the difference between H2 and H1 is less than or equal to 30 μm.

[0015] In some embodiments, along the second direction, the width of the first portion is W1, and the width of the insulating block is W3, where W1 < W3; The difference between W3 and W1 is 150 to 750 μm, and / or the ratio of W3 to W1 is 2 to 45.

[0016] In some embodiments, along the first direction: the length of the first portion is D1, and the length of the insulating block is D2; The ratio of D1 to D2 is between 0.3 and 3, and / or the absolute value of the difference between D1 and D2 is less than or equal to 4 mm.

[0017] In some embodiments, the back contact battery cell further includes: an interconnect portion located on the side of the current collector electrode away from the battery body; along the second direction, the interconnect portion spans at least two adjacent current collector electrodes, wherein one polarity current collector electrode is not covered by an insulating block at the position corresponding to the interconnect portion, forming an electrical connection, and the other polarity current collector electrode is covered by an insulating block at the position corresponding to the interconnect portion; along the first direction: the length of the first portion is D1, the width of the interconnect portion is W4, 0.5≤W4 / D1≤1.5; and / or, In some embodiments, the back contact battery cell further includes: a bus electrode located on the side of the current collector electrode away from the battery body; along the second direction, the bus electrode spans at least two adjacent current collector electrodes, wherein one polarity current collector electrode is not covered by an insulating block at the position corresponding to the bus electrode, and the other polarity current collector electrode is covered by an insulating block at the position corresponding to the bus electrode; along the first direction: the width of the bus electrode is W5, the length of the first portion is D1, and 3≤D1 / W5≤15.

[0018] In some embodiments, the back contact cell further includes: an interconnect portion, which spans at least one current collector electrode of one polarity along the second direction and forms an electrical connection with the current collector electrode of the one polarity; and an insulating block covering the extension of the interconnect portion of another polarity adjacent to the interconnect portion along the second direction.

[0019] In some embodiments, along the thickness direction of the battery body, the height difference between the surface of the bus electrode away from the battery body and the surface of the adjacent insulating block away from the battery body is less than or equal to 5 μm.

[0020] In some embodiments, in the same current collector electrode: the surface roughness of the first portion away from the battery body is greater than the surface roughness of the second portion away from the battery body.

[0021] In some embodiments, in the same current collector electrode, along the first direction, the undulation of the contour line of the first portion is less than the undulation of the contour line of the second portion.

[0022] In some embodiments, along the second direction, the surface of the first portion away from the battery body is undulating, and the first portion has at least two peaks. And / or, the first portion includes an edge portion located at the edge and a middle portion located between the two edge portions, the height of the middle portion being lower than the height of the edge portions; And / or, the difference between the highest and lowest points of the wave crest is greater than or equal to 0.3 micrometers. In some embodiments, along the first direction, the surface of the second portion away from the battery body has a wave-like undulation, the difference between the highest and lowest points of the wave-like undulation is greater than or equal to 0.5 micrometers.

[0023] In some embodiments, the first surface includes: a first conductive region and a second conductive region sequentially disposed along the second direction, the first current collector electrode being disposed in the first conductive region, and the second current collector electrode being disposed in the second conductive region; the width of the second conductive region along the second direction is greater than the width of the first conductive region along the second direction. The number of second collector electrodes disposed on a second conductive region is equal to the number of first collector electrodes disposed on a first conductive region; the width of the first portion of the second collector electrode on the second conductive region is greater than the width of the first portion of the first collector electrode on the first conductive region; and / or, the width of the second portion of the second collector electrode on the second conductive region is greater than the width of the second portion of the first collector electrode on the first conductive region. Alternatively, the number of second collector electrodes disposed on a second conductive region is greater than the number of first collector electrodes disposed on a first conductive region; the width of the first portion of the second collector electrode on the second conductive region is less than the width of the first portion of the first collector electrode on the first conductive region; and / or, the width of the second portion of the second collector electrode on the second conductive region is less than the width of the second portion of the first collector electrode on the first conductive region.

[0024] In some embodiments, the first surface includes: a first conductive region and a second conductive region sequentially disposed along the second direction, the first current collector electrode being disposed in the first conductive region, and the second current collector electrode being disposed in the second conductive region; the battery body further includes a semiconductor substrate, and the conductivity type of the second conductive region is opposite to the conductivity type of the silicon substrate; The difference between the width of the second portion of the second collector electrode and the width of the first portion is W6, and the difference between the width of the second portion of the first collector electrode and the width of the first portion is W7, where W6 > W7. And / or, the height difference between the second portion of the second collector electrode and the height of the first portion is H4, and the height difference between the second portion of the first collector electrode and the height of the first portion is H5, where H4 > H5.

[0025] And / or, The aspect ratio of the first portion of the second collector grid line is greater than that of the first portion of the first collector grid line; the aspect ratio of the second portion of the second collector grid line is greater than that of the second portion of the first collector grid line.

[0026] In some embodiments, the first surface includes: a first conductive region and a second conductive region sequentially disposed along the second direction, wherein the first current collector electrode is disposed in the first conductive region and the second current collector electrode is disposed in the second conductive region; The first conductive region is further away from the second surface than the second conductive region; the height of the first portion of the second current collector electrode is greater than the height of the first portion of the first current collector electrode; and / or, the height of the second portion of the second current collector electrode is greater than the height of the second portion of the first current collector electrode; and / or, the height of the insulating block on the second current collector electrode is greater than the height of the insulating block on the first current collector electrode; or... The second conductive region is further away from the second surface than the first conductive region; the height of the first portion of the first collector electrode is greater than the height of the first portion of the second collector electrode; and / or, the height of the second portion of the first collector electrode is greater than the height of the second portion of the second collector electrode; and / or, the height of the insulating block on the first collector electrode is greater than the height of the insulating block on the second collector electrode.

[0027] In some embodiments, at least one current collector electrode located near the edge of the cell is disconnected.

[0028] In some embodiments, the current collector electrode is a base metal electrode; and / or, H1 is 2-20 μm, and / or H2 is 5-50 μm; In the same current collector electrode: the width of at least a first portion covered by the insulating block is W1, and the width of at least a second portion not covered by the insulating block is W2, where W1 is 20-100 μm, and / or W2 is 20-100 μm; and / or, The height of the insulating block is H3, where H3 can be 12-55 μm; and / or, The width of the insulating block is W3, where W3 is 300-800 μm; and / or, Along the first direction: the length of the first part is D1, the length of the insulating block is D2, D1 is 1-5mm, and / or, D2 is 1-5mm.

[0029] In some embodiments, the battery body includes a doped layer, and the current collector electrode is electrically connected to the doped layer; The doped layer near the edge of the back contact cell is called an edge doped layer. The current collector on the edge doped layer is closer to the interior of the back contact cell, and / or the width of the edge doped layer is smaller than the width of the doped layer inside the back contact cell.

[0030] A second aspect of this application provides a printing plate, comprising: A plurality of printing areas extending along a first direction and arranged sequentially along a second direction; the printing areas include a third part and a fourth part continuously arranged along the first direction; The height of the third part is H6, and the height of the fourth part is H7, where H6 < H7.

[0031] Compared to the screen printing method used in related technologies to form current collector electrodes, the current collector electrodes printed on the printing steel plate provided in this application have a higher degree of flatness. As a result, the current collector electrodes themselves have lower bulk resistance and narrower line width, which not only reduces the risk of short circuits but also increases series resistance, thereby improving the power generation efficiency of the back contact cell.

[0032] In some embodiments, the third portion does not contain printed steel wires, while the fourth portion contains parallel-distributed printed steel wires; or, Both the third and fourth parts are provided with parallel printed steel wires, and the number of printed steel wires in the third part is less than the number of printed steel wires in the fourth part per unit area.

[0033] In some embodiments, the width of the printed wire is 8-15 μm, and / or the spacing between adjacent printed wires is less than or equal to 80 μm.

[0034] A third aspect of this application provides a photovoltaic module, comprising: an interconnecting element and a plurality of any of the aforementioned back-contact solar cells; The interconnect extends along a second direction and is electrically connected to an interconnect portion of a current collector of one polarity; and along the second direction, the interconnect spans a current collector of another polarity, with an insulating block disposed between the interconnect and the current collector of the other polarity. In some embodiments, the width of the interconnect is W8, and the length of the first portion is D1, where 0.1 ≤ W8 / D1 ≤ 1.

[0035] The aforementioned back-contact solar cells, printed steel plates, and photovoltaic modules have the same or similar beneficial effects, and will not be repeated here to avoid repetition. Attached Figure Description

[0036] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 , Figure 11 and Figure 12 The following are schematic diagrams illustrating the structures of two back-contact battery cells in embodiments of this application; Figure 2 A partial cross-sectional view of a current collector electrode in an embodiment of this application is shown; Figure 3 A partial top view of a back-contact battery cell in an embodiment of this application is shown; Figure 4 A partial top view of a photovoltaic module according to an embodiment of this application is shown; Figure 5A schematic diagram of the short-circuit structure of a photovoltaic module in the related technology is shown; Figure 6 A partial top view of a current collector electrode in an embodiment of this application is shown; Figure 7 A top view of the structure of a current collector electrode and an insulating block in an embodiment of this application is shown; Figure 8 This paper shows a SEM image of a current collector electrode on the battery body in an embodiment of this application; Figure 9 A partial 3D microscope top view of the battery body in back contact with the battery cell in an embodiment of this application is shown; Figure 10 A cross-sectional SEM image of the first part in an embodiment of this application is shown; Figure 13 A partial top view of the back contact battery cell in an embodiment of this application is shown; Figure 14 A schematic diagram of the structure of a printing plate according to an embodiment of this application is shown.

[0037] Explanation of the attached drawing numbers: 1-Battery body, 21-First current collector electrode, 22-Second current collector electrode, 23-First part, 231-Edge part, 232-Middle part, 24-Second part, 25-Printed protrusions of current collector electrode, 3-Insulating block, 4-Interconnection part, 5-Bucket electrode, 6-Interconnection element, 7-Semiconductor substrate, 8-First doped layer, 9-Second doped layer, 10-Surface passivation layer, 11-Tunneling oxide layer, 12-Inner expansion layer, 13-Intrinsic amorphous silicon layer, 14-Spacer region, 15-Transparent conductive layer, 16-First conductive region, 17-Second conductive region, 18-Battery cell edge line, 19-Printed area, 191-Third part, 192-Fourth part, 193-Printed wire, 20-Printed area corresponding to insulating block. Detailed Implementation

[0038] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated 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 this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0039] This application provides a back contact battery cell, as shown in the reference. Figure 1The back contact solar cell includes a battery body 1, which contains a PN junction. Along its thickness direction L1, the battery body 1 includes a first surface and a second surface facing each other. Of these, the first surface is the backlight surface, and the second surface is the light-facing surface. During operation, the side of the battery body 1 that primarily receives light is its light-facing surface, while the backlight surface and the light-facing surface face each other. For example, Figure 1 In the middle, the upper surface of the battery body 1 is its backlight surface, and the lower surface is its light-facing surface.

[0040] Figure 1 It is a longitudinal cross-sectional view along the direction perpendicular to the extension direction of the current collector electrode, i.e., the second direction. Figure 2 It is a longitudinal cross-sectional view of the extension direction of the collector electrode, i.e., the first direction. Figure 3 This is a partial top view of the back contact cell. Figure 2 yes Figure 3 The cross section corresponding to AA in the middle. Figure 3 The enlarged view of the area enclosed by the dashed box corresponds to the following. Figure 6 and Figure 7 . Figure 4 A partial structural diagram of a photovoltaic module. Figure 2 Too Figure 4 China A ， -A ， The corresponding cross-section, Figure 4 The enlarged view of the area outlined by the dashed box in the lower center corresponds to the following. Figure 6 and Figure 7 . Reference Figures 1 to 4 Several current collectors are disposed on the first surface of the battery body 1, i.e., the backlight surface, and extend along the first direction L3. These current collectors are used to collect charge carriers or current in the battery body. The extension of the current collectors along the first direction L3 can be understood as the overall orientation of the current collectors being along the first direction L3, but local bending in other directions is permitted. The several current collectors include: a first current collector 21 and a second current collector 22, sequentially distributed along the second direction L2. Along the second direction L2, the first current collector 21 and the second current collector 22 can be alternately distributed, or two or more second current collectors can be continuously distributed sequentially along the second direction, all of which are within the scope of protection of this application. For example, refer to... Figure 1 Along the second direction L2, a first collector electrode 21 is connected to a second collector electrode 22, and then another first collector electrode 21 is connected in this manner. In this application, the first direction L3 intersects the second direction L2, and the included angle between the two is not limited, for example, it can be 90°.

[0041] The insulating block 3 is located in a localized area on the side of the battery body 1 away from the current collector electrodes that are continuously arranged along the first direction L3. The insulating block 3 only needs to provide good insulation; its specific material is not limited, for example, it can be thermosetting insulating adhesive or photocuring insulating adhesive. The fact that the current collector electrodes are continuously arranged along the first direction L3 indicates that there are no gaps between them. Normally, when current collector electrodes are spaced out, the carriers or current in the gapped areas cannot be effectively collected, which reduces battery performance. In this application, because the current collector electrodes are continuously arranged along the first direction L3 without any breaks, the carrier or current collection area is wider, thus improving battery performance.

[0042] Figure 5 This is a partial schematic diagram of a photovoltaic module based on related technologies. (Refer to...) Figure 5 For printed current collector electrodes, it is usually unavoidable to have printed protrusions 25. The printing protrusions 25 of the current collector electrode penetrating or adjacent to the insulating block 3 is a major cause of short circuits in the back contact cell.

[0043] To address the aforementioned technical issues, refer to Figure 2 In the same current collector electrode: the height of at least the first portion 23 covered by the insulating block 3 is H1, and the height of at least the second portion 24 not covered by the insulating block 3 is H2, where H1 < H2. (Refer to...) Figure 4 and Figure 5 In the same current collector electrode, the portion covered by the insulating block 3 typically has conductive structures such as interconnects 6 and bus electrodes 5 that are electrically connected to current collector electrodes of the opposite polarity. If the printed protrusions of this portion of the current collector electrode penetrate the insulating block, the interconnects and bus electrodes connected to the current collector electrodes of the opposite polarity will form an electrical connection, thus posing a short circuit risk. The portion not covered by the insulating block 3 generally does not have conductive structures such as interconnects and bus electrodes connected to current collector electrodes of the opposite polarity, and therefore poses virtually no short circuit risk. In this application, the height H1 of at least the first portion of the same current collector electrode covered by the insulating block 3 that poses a short circuit risk is smaller than the height H2 of at least the second portion not covered by the insulating block 3 that poses virtually no short circuit risk. This significantly reduces the height of the printed protrusions in the first portion of the same current collector electrode covered by the insulating block 3 that poses a short circuit risk, thereby significantly reducing the short circuit risk caused by the printed protrusions penetrating or being near the insulating block in the first portion of the same current collector electrode, thus improving battery performance and reliability. The first part 23 here refers to all or part of the same current collector electrode that is covered by the insulating block 3. The second part 24 here refers to all or part of the same current collector electrode that is not covered by the insulating block 3; in the case of a partial coverage, the specific location and size are not limited.

[0044] Meanwhile, in this application, the second part 24, which has virtually no short-circuit risk, has a relatively large height, enabling good current collection and transmission capabilities. Furthermore, in the back-contact solar cell, the presence of the insulating block locally increases the height, while the area without the insulating block has a lower height. This height difference becomes more pronounced after further placing bus electrodes or interconnects (such as solder pads) above the insulating block. On the one hand, this height difference hinders the formation of an effective connection between the back-contact solar cell and external interconnects (such as solder ribbons), easily leading to poor contact between the bus electrodes or interconnects (PADs) and the interconnects (solder ribbons). On the other hand, the height difference makes the back-contact solar cell prone to microcracks during lamination, affecting process yield. Therefore, in this application, the height of the current collector electrode below the insulating block is reduced, which also correspondingly reduces the overall height difference or undulation, increasing the reliability of subsequent module-end stringing and lamination, and forming an effective connection.

[0045] In summary, this application balances current harvesting efficiency and short-circuit risk, not only reducing short-circuit risk but also improving current harvesting efficiency, thereby enhancing battery performance and reliability.

[0046] It should be noted that, referring to Figure 2 When the height of the first part varies at different locations, the height of the first part can be its minimum height, or the arithmetic mean of the heights at two, three, or more locations. The method for determining the height of the second part is the same or similar, and will not be repeated here to avoid repetition. The heights of the first and second parts, both near the starting point of the battery body, can be on the same horizontal line. The directions of the heights of both the first and second parts are parallel to the direction L1 of the battery body's thickness.

[0047] This can be in the same first collector electrode 21: the height of at least the first portion covered by the insulating block 3 is H1, the height of at least the second portion not covered by the insulating block is H2, H1 < H2, and the number of first collector electrodes 21 is greater than or equal to 1; or, this can be in the same second collector electrode 22: the height of at least the first portion covered by the insulating block 3 is H1, the height of at least the second portion not covered by the insulating block is H2, H1 < H2, and the number of second collector electrodes 22 is greater than or equal to 1. The number of first collector electrodes 21 is equal to 1; or, in the same first collector electrode 21: the height of at least the first portion covered by the insulating block 3 is H1, the height of at least the second portion not covered by the insulating block is H2, H1 < H2, and the number of first collector electrodes 21 is greater than or equal to 1; and, in the same second collector electrode 22: the height of at least the first portion covered by the insulating block 3 is H1, the height of at least the second portion not covered by the insulating block is H2, H1 < H2, and the number of second collector electrodes 22 is greater than or equal to 1. All of the above situations are within the scope of protection of this application.

[0048] It should be noted that, similar to the above explanation, this application does not specify whether it is the first collector electrode or the second collector electrode. Whether it applies to at least one first collector electrode, or to at least one second collector electrode, or to both at least one first collector electrode and at least one second collector electrode, all are within the scope of protection of this application.

[0049] In some possible embodiments, refer to Figure 1 The height of insulating block 3 is H3, where H3 > H1, ensuring that the portion of the current collector electrode covered by the insulating block does not extend beyond it, thus reducing the risk of short circuits. It should be noted that, referring to... Figure 1 and Figure 2 When the height of insulating block 3 varies at different positions, the height of insulating block 3 at this point can be the maximum height of insulating block 3, or the arithmetic mean of the heights at 2, 3, etc. positions. The direction of the height of insulating block 3 is also parallel to the thickness direction of the battery body.

[0050] In some possible embodiments, based on H3 > H1, the difference between H3 and H1 is greater than or equal to 5 μm. The height difference between the portion of the current collector electrode covered by the insulating block and the insulating block is relatively large, further avoiding the risk of short circuits during subsequent stringing and lamination. For example, the difference between H3 and H1 can be 5 μm, 8 μm, 10 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. Here, the difference between H3 and H1 can be the height difference between the insulating block 3 and the height of at least a first portion of a current collector electrode covered by that insulating block; or it can be the height difference between one insulating block and the height of at least a first portion of a current collector electrode covered by another insulating block. The polarities of the current collector electrodes covered by one insulating block and the other insulating block can be the same or different, and this is not limited. For example, the difference between H3 and H1 could be the difference between the height of the insulating block 3 covering one second collector electrode and the height of at least a first portion of one first collector electrode covered by the insulating block 3. As another example, the difference between H3 and H1 could be the difference between the height of the insulating block 3 covering one first collector electrode and the height of at least a first portion of another first collector electrode covered by the insulating block 3. As yet another example, the difference between H3 and H1 could be the difference between the height of the insulating block 3 covering one first collector electrode and the height of at least a first portion of one second collector electrode covered by the insulating block 3.

[0051] In some possible embodiments, based on H3 > H1, the ratio of H3 to H1 is greater than or equal to 1.2 and less than or equal to 15. If the ratio of H3 to H1 is too large, there may be wasted insulating blocks; if the ratio is too small, there may be a short-circuit risk. Therefore, a ratio within the above range can avoid waste, reduce costs, and minimize the risk of short circuits. For example, the ratio of H3 to H1 can be 1.2, 1.5, 1.8, 2, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 11.3, 12.5, 3, 13.2, 13.5, 14, or 15. Whether H3 and H1 correspond to the same insulating block or the same current collector electrode is not limited here; refer to the relevant descriptions of the difference between H3 and H1 mentioned above.

[0052] In some possible embodiments, H1 can be 1.5-23 μm, and more specifically, 2-20 μm. If H1 is too small, the resistance of the portion of the collector electrode covered by the insulating block may be high, resulting in poor current collection. If H1 is too large, it may cause a short circuit risk. Therefore, within this range, H1 not only ensures good current collection but also minimizes the risk of short circuits. For example, H1 can be 1.5 μm, 2 μm, 2.8 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 8 μm, 10 μm, 11 μm, 14 μm, 15 μm, 17 μm, 18 μm, 20 μm, or 23 μm. Here, the range of H1 can be applicable to both the first and second collector electrodes. Similarly, the ranges of H2 and H3 can also be applicable to both the first and second collector electrodes.

[0053] In some possible embodiments, H3 can be 12-55μm, and more specifically 15-50μm. If H3 is too small, it may introduce a short-circuit risk; if H3 is too large, it may introduce microcracks into the photovoltaic module, and the cost of the insulating block will also be too high. Therefore, H3 within this range not only ensures a low short-circuit risk but also a low microcrack risk and a low cost. For example, H3 can be 12μm, 15μm, 18μm, 20μm, 22μm, 24μm, 25μm, 30μm, 35μm, 36μm, 40μm, 47μm, 48μm, 50μm, 51μm, 54μm, or 55μm.

[0054] In some possible embodiments, the ratio of H2 to H1 is greater than 1.1 and less than or equal to 5. Specifically, if the ratio is too small, it indicates that the collector grid line covered by the insulating block is too high, and there is still a risk of short circuit. If the ratio is too large, the conductivity difference between the part of the collector electrode covered by the insulating block and the part not covered by the insulating layer is too large, affecting the current collection effect. In addition, when the first part is a partial area covered by the insulating block, it indicates that the insulation coverage area is larger, and the second part connected to the first part may also be partially covered under the insulating block, such as... Figure 2 As shown, if the ratio of H2 to H1 is too large, the second part below the insulating block still risks puncturing the insulating adhesive and causing a short circuit. Therefore, when the ratio is within the above range, not only is the risk of a short circuit low, but the current collection effect is also good. For example, the ratio of H2 to H1 can be 1.1, 1.3, 1.5, 1.9, 2, 2.3, 2.5, 3, 3.1, 3.5, 3.7, 4, 4.3, 4.7, or 5.

[0055] In some possible embodiments, the difference between H2 and H1 is less than or equal to 30 μm. Specifically, if the difference is too large, the conductivity difference between the portion of the current collector electrode covered by the insulating block and the portion not covered by the insulating layer will be too large, affecting the current collection effect. Therefore, a difference within the above range not only ensures a low short-circuit risk but also good current collection performance. For example, the difference between H2 and H1 can be 1 μm, 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 15 μm, 20 μm, 22 μm, 25 μm, 28 μm, or 30 μm.

[0056] In some possible embodiments, H2 can be 5-50 μm, and more specifically, 5-30 μm. Specifically, an excessively large H2 may lead to excessively high costs for the collector electrode, while an excessively small H2 may result in poor current collection performance. Therefore, H2 within the aforementioned range ensures that not only are the costs of the collector electrode not excessively high, but also that the current collection performance is good.

[0057] For example, H2 can be 5μm, 8μm, 10μm, 12μm, 14μm, 15μm, 20μm, 22μm, 25μm, 28μm, 30μm, 35μm, 40μm, 42μm, 45μm, 48μm, or 50μm.

[0058] Figure 6 This is a top view schematic diagram of a single current collector electrode. In some possible embodiments, refer to... Figure 6In the same current collector electrode: along the second direction L2, the width of at least the first portion 23 covered by the insulating block 3 is W1, and the width of at least the second portion 24 not covered by the insulating block 3 is W2, where W1 < W2. In this application, in the same current collector electrode: along the second direction L2, the width W1 of the at least first portion covered by the insulating block 3 that has a short-circuit risk is smaller than the width W2 of the at least second portion not covered by the insulating block 3 that has essentially no short-circuit risk. This can significantly reduce the distribution width of the printed protrusions in the at least first portion covered by the insulating block 3 that has a short-circuit risk in the same current collector electrode, thereby significantly reducing the short-circuit risk caused by the printed protrusions penetrating or being adjacent to the insulating block in the at least first portion of the same current collector electrode that has a short-circuit risk, and improving battery performance. The definitions of the first portion 23 and the second portion 24 here refer to the aforementioned relevant descriptions, and will not be repeated here to avoid repetition.

[0059] It should be noted that, referring to Figure 6 When the width of the first part varies at different locations, the width of the first part can be the minimum width of the first part, or the arithmetic mean of the widths at 2, 3, etc. locations. The method for determining the width of the second part is the same or similar, and will not be repeated here to avoid repetition. The directions of the widths of the first and second parts are parallel to the second direction L2. In cases where the dimensions of certain structures differ at different locations in this application, the method for determining these dimensions can refer to the method for determining the width here, and will not be repeated here to avoid repetition.

[0060] This could be within the same first collector electrode 21: along the second direction L2, the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2, where W1 < W2, and the number of first collector electrodes 21 is greater than or equal to 1; or, this could be within the same second collector electrode 22: the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2, where W1 < W2, and the number of second collector electrodes 21 is greater than or equal to 1. The number of first collector electrodes 21 is greater than or equal to 1; or, in the same first collector electrode 21: the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2, where W1 < W2, and the number of first collector electrodes 21 is greater than or equal to 1; and, in the same second collector electrode 22: the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2, where W1 < W2, and the number of second collector electrodes 22 is greater than or equal to 1. All of the above situations are within the scope of protection of this application.

[0061] In some possible embodiments, in the same first current collector electrode 21: along the second direction L2, the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2. Based on W1 < W2, the difference between W2 and W1 is greater than or equal to 1 μm and less than or equal to 50 μm. Specifically, if this difference is too small, it indicates that the width W1 of the first portion covered by the insulating block 3, which poses a short-circuit risk, is still relatively large, and the distribution width of the printed spikes in the first portion covered by the insulating block 3 is still relatively large, meaning there is still a certain short-circuit risk in the current collector electrode. If the difference is too large, it indicates that W1 is too small, and the collection of carriers in the doped layer at the corresponding position may not be guaranteed in the first portion covered by the insulating block 3, and the conductivity of the first and second portions differs significantly, affecting the performance of the back contact battery. Therefore, in this application, the difference between W2 and W1 is 1 μm to 50 μm, which balances low short-circuit risk and good conductivity such as carrier collection.

[0062] For example, the difference between W2 and W1 can be 1μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, or 50μm.

[0063] In some possible embodiments, in the same first current collector electrode 21: along the second direction L2, the width of at least the first portion covered by the insulating block 3 is W1, and the width of at least the second portion not covered by the insulating block is W2. Based on W1 < W2, the ratio of W2 to W1 is 1.1 to 3. Specifically, if this ratio is too small, it indicates that the width W1 of the first portion covered by the insulating block 3, which poses a short-circuit risk, is still relatively large, and the distribution width of the printed spikes in the first portion covered by the insulating block 3 is still relatively large, meaning there is still a certain short-circuit risk in the current collector electrode. If the ratio is too large, it indicates that the difference between W2 and W1 is too large, and if W1 is too small, the collection of carriers in the doped layer at the corresponding position in the first portion covered by the insulating block 3 may not be guaranteed, and the conductivity of the first and second portions differs significantly, affecting the performance of the back contact battery. Therefore, in this application, the ratio of W2 to W1 is 1.1 to 3, which balances low short-circuit risk and good conductivity such as carrier collection.

[0064] For example, the ratio of W2 to W1 can be 1.1, 1.3, 1.5, 1.9, 2, 2.2, 2.5, 2.8, or 3.

[0065] In some possible embodiments, refer to Figure 6W2 can be 20-100μm. If W2 is too small, it may affect the current collection effect; if W2 is too large, it may lead to material waste and increased costs. Therefore, W2 is within the above range to ensure the current collection effect and avoid material waste. For example, W2 can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 80μm, 90μm, or 100μm.

[0066] In some possible embodiments, within the same current collector electrode, the aspect ratio of the second portion not covered by the insulating block is greater than that of the first portion covered by the insulating block 3. Specifically, a larger aspect ratio results in less light shading and lower bulk resistance, leading to less energy loss during current transmission. Within the same current collector electrode, along the first direction, the proportion of the length of the second portion not covered by the insulating block 3 is larger than that of the first portion covered by the insulating block 3. In this application, the larger aspect ratio of the second portion further reduces light shading and lowers resistance, resulting in less energy loss during current transmission and a lower risk of short circuits, thus further improving battery performance.

[0067] It should be noted that, in the process of comparing the aspect ratio of the first part and the second part, the first part and the second part can be on the same collector electrode, which can be either the first collector electrode or the second collector electrode.

[0068] Figure 7 A perspective view of the current collector electrode covered by an insulating block. Figure 7 It can be Figure 3 An enlarged schematic diagram showing the interaction between the insulating block and the current collector electrode, as outlined by the dashed line. In some possible embodiments, refer to... Figure 6 and Figure 7 Along the second direction L2, the width of the first part is W1, and the width of the insulating block 3 is W3, where W1 < W3. This ensures that the portion of the current collector electrode covered by the insulating block does not exceed the insulating block in the width direction, reducing the risk of short circuits. It should be noted that when the width of the insulating block 3 varies at different positions, the width of the insulating block 3 here can be the maximum width of the insulating block 3, or the arithmetic mean of the widths at two, three, or more positions. The direction in which the width of the insulating block 3 lies is along the second direction.

[0069] In some possible embodiments, based on W3 > W1, the difference between W3 and W1 is 150 to 750 μm, and more specifically, it can be 200 to 700 μm. If the difference between the portion of the current collector electrode covered by the insulating block and the width of the insulation block is too large, the insulating block may be wasted; if the difference is too small, there may be a short-circuit risk. Therefore, a width difference within the above range not only reduces cost but also lowers the short-circuit risk. For example, the difference between W3 and W1 can be 150 μm, 200 μm, 250 μm, 280 μm, 300 μm, 350 μm, 380 μm, 40 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, or 750 μm. The difference between W3 and W1 here can be the difference between the width of an insulating block 3 and the width of at least a first portion of a current collector electrode covered by the insulating block 3; or it can be the difference between the width of an insulating block 3 and the width of at least a first portion of a current collector electrode covered by another insulating block. Here, the polarity of the current collector electrode covered by the former insulating block and the current collector electrode containing the aforementioned first portion can be the same or different, and this is not limited. For example, the difference between W3 and W1 can be the difference between the width of an insulating block 3 covering a second current collector electrode and the width of at least a first portion of a first current collector electrode covered by the insulating block 3. As another example, the difference between W3 and W1 can be the difference between the width of an insulating block 3 covering a first current collector electrode and the width of at least a first portion of another first current collector electrode covered by the insulating block 3. For example, the difference between W3 and W1 could be the difference between the width of the insulating block 3 covering a first collector electrode and the width of at least a first portion of a second collector electrode covered by the insulating block 3.

[0070] In some possible embodiments, based on the premise that W3 > W1, the ratio of W3 to W1 is 2 to 45, and further, it can be 3 to 40. If the ratio of W3 to W1 is too large, there may be wasted insulating blocks; if the ratio of W3 to W1 is too small, there may be a short circuit risk. Therefore, a ratio within the above range can avoid waste, reduce costs, and minimize the risk of short circuits. For example, the ratio of W3 to W1 can be 2, 2.3, 2.5, 2.8, 3, 3.2, 3.5, 4, 4.5, 5, 6, 7, 8, 10, 11.3, 12.5, 3, 13.2, 13.5, 14, 15, 20, 22, 25, 30, 33, 35, 37, or 40. The determination of the ratio of W3 to W1 here refers to the determination of the width of the insulating block and the width of at least the first part of a current collector electrode covered by the insulating block 3, in accordance with the determination method related to the difference between W3 and W1 mentioned above. To avoid repetition, it will not be repeated.

[0071] In some possible embodiments, refer to Figure 6W1 can be 20-100μm. If W1 is too small, it may affect the current collection effect; if W1 is too large, it may lead to a short circuit risk. Therefore, W1 is within the above range to ensure the current collection effect and reduce the short circuit risk. For example, W1 can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 80μm, 90μm, or 100μm.

[0072] In some possible embodiments, refer to Figure 7 W3 can be 300-800μm. Too small a W3 may cause a short circuit risk, while too large a W3 may lead to material waste. Therefore, W3 is within the above range to avoid material waste and reduce the risk of short circuits. For example, W3 can be 300μm, 350μm, 380μm, 400μm, 450μm, 500μm, 550μm, 600μm, 650μm, 700μm, 750μm, or 800μm.

[0073] In some possible embodiments, refer to Figure 7 Along the first direction L3: the length of the first part is D1, and the length of the insulating block 3 is D2. The ratio of D1 to D2 is between 0.3 and 3. Specifically, if this ratio is too small, the lower first part is too short, and there is still a risk of short circuit. If this ratio is too large, the lower first part is too long, which may affect the current collection effect. Therefore, the ratio of the two is within the above range, which can reduce the risk of short circuit and improve the current collection effect.

[0074] For example, the ratio of D1 to D2 can be 0.3, 0.4, 0.5, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.4, 1.5, 2, 2.2, 2.5, or 3.

[0075] When the length of the first part varies at different locations, the length of the first part here can be its minimum length, or the average of the lengths at 2, 3, etc. locations. The method for determining the length of insulating block 3 is similar, and will not be repeated here to avoid repetition.

[0076] In some possible embodiments, refer to Figure 7 Along the first direction L3: the length of the first part is D1, and the length of the insulating block 3 is D2. The absolute value of the difference between D1 and D2 is less than or equal to 4mm. Specifically, if the absolute value of this difference is too large, it indicates that the lower first part is too short, and there is still a risk of short circuit. Alternatively, if the lower first part is too long, it may affect the current collection effect. Therefore, if the absolute value of the difference between the two is within the above range, it can reduce the risk of short circuit and improve the current collection effect.

[0077] For example, the absolute value of the difference between D1 and D2 can be 0, 0.4mm, 0.5mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 3mm, 3.5mm, or 4mm.

[0078] It should be noted that in determining the ratio of D1 to D2 and the absolute value of the difference between D1 and D2, the first part corresponding to D1 may be covered by the insulating block corresponding to D2, or the first part corresponding to D1 may be covered by other insulating blocks, while the insulating block corresponding to D2 may not cover the first part corresponding to D1; all of these are within the scope of protection of this application. When the first part corresponding to D1 is covered by other insulating blocks, whether the polarity of the first part is the same as the polarity of the current collector electrode covered by other insulating blocks is within the scope of protection of this application. This is similar to the determination method of W3 and W1 in the aforementioned difference between W3 and W1, and will not be repeated here to avoid repetition.

[0079] In some possible embodiments, refer to Figure 7 Along the first direction L3: the length of the first part is D1, which is 1-5mm, which can reduce the risk of short circuit and improve the current collection effect.

[0080] For example, the length of the first part, D1, can be 1mm, 1.1mm, 1.2mm, 1.5mm, 2mm, 2.2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.2mm, 4.5mm, or 5mm.

[0081] In some possible embodiments, refer to Figure 7 Along the first direction L3: the length of the insulating block 3 is D2, which is 1-5mm. The length of D2 is related to the size of the conductive structure that will pass through it and be electrically connected to the current collector electrode of the opposite polarity. The length of the insulating block 3 is within the above range, which not only reduces the risk of short circuit, but also provides good insulation and avoids material waste.

[0082] For example, the length D2 of the insulating block 3 can be 1mm, 1.1mm, 1.2mm, 1.5mm, 1.8mm, 2mm, 2.2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.2mm, 4.5mm, or 5mm.

[0083] In some possible embodiments, refer to Figure 4The back contact cell also includes: an interconnect portion 4, located on the side of the current collector electrode facing away from the battery body, along the second direction L2. This interconnect portion 4 spans at least two adjacent current collector electrodes. Of these at least two adjacent current collector electrodes, one polarity current collector electrode, at its position corresponding to the interconnect portion 4, is not covered by an insulating block and forms an electrical connection with the interconnect portion 4; the other polarity current collector electrode, at its position corresponding to the interconnect portion 4, is covered by an insulating block 3 and is insulated from the interconnect portion. For example, Figure 4 In the diagram, the interconnect portion 4, located near L2, spans three adjacent collector electrodes. Of these three collector electrodes, the position of the second collector electrode 22 corresponding to the interconnect portion 4 is covered by an insulating block 3, thus isolating the second collector electrode 22 from the interconnect portion 4. The position of the first collector electrode 21 corresponding to the interconnect portion 4 is not covered by the insulating block 3, and the first collector electrode 21 is electrically connected to the interconnect portion 4. The interconnect portion 4 is used to conduct current on the first collector electrode 21. (Refer to...) Figure 4 and Figure 7 Along the first direction L3: the width of the interconnect 4 is W4, and the length of the first part is D1, where 0.5 ≤ W4 / D1 ≤ 1.5. If W4 / D1 is too small, there may be a problem with poor current collection; if W4 / D1 is too large, there may be a risk of short circuit to the interconnect 4. Therefore, W4 / D1 is within the above range, resulting in good current collection and low short circuit risk. In determining W4 / D1, there are no restrictions on whether the interconnect 4 and the first part are positioned opposite each other or electrically connected. This is similar to the determination method of W3 and W1 in the difference between W3 and W1 mentioned above, and will not be repeated here to avoid repetition.

[0084] For example, W4 / D1 can be 0.5, 0.6, 0.67, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, or 1.5.

[0085] It should be noted that the interconnect portion 4 can be a separate component or a thickened section of the collector electrode. When the interconnect portion 4 is a thickened section of the collector electrode, the thickened section is thicker than the rest of the collector electrode. The interconnect portion can be an electrode disk, etc. Here, in determining W4 / D1, it is not limited whether the interconnect portion corresponding to W4 covers the first part corresponding to D1. It is also not limited whether the interconnect portion corresponding to W4 covers the first part corresponding to D1, or whether the interconnect portion corresponding to W4 does not cover the first part corresponding to D1, or whether the collector electrodes of polarity of the interconnect portion corresponding to W4 and the first part corresponding to D1 are electrically connected. For example, the interconnect portion corresponding to W4 can be the width of the interconnect portion electrically connected to the first collector electrode, and the first part corresponding to D1 can be the length of at least the first part of the first collector electrode covered by the insulating block, or the first part corresponding to D1 can be the length of at least the first part of the second collector electrode covered by the insulating block. For example, the interconnect portion corresponding to W4 can be the width of the interconnect portion electrically connected to the second collector electrode, and the first portion corresponding to D1 can be the length of at least the first portion of the first collector electrode covered by the insulating block, or the first portion corresponding to D1 can be the length of at least the first portion of the second collector electrode covered by the insulating block. The above examples are all within the scope of protection of this application.

[0086] In some possible embodiments, refer to Figure 4 The back contact solar cell also includes a bus electrode 5, located on the side of the current collector electrode facing away from the battery body, along the second direction L2. The bus electrode 5 spans at least two adjacent current collector electrodes. Of these at least two adjacent current collector electrodes, the position corresponding to one polarity of the current collector electrode and the bus electrode 5 is not covered by the insulating block 3, while the position corresponding to the other polarity of the current collector electrode and the bus electrode 5 is covered by the insulating block 3. The bus electrode is electrically connected to the current collector electrode not covered by the insulating block 3. This back contact solar cell is a back contact solar cell with a main grid. For example, Figure 4 In the diagram, the bus electrode 5, located near L2 (or on the far left), spans multiple adjacent collector electrodes. Of these adjacent collector electrodes, the position corresponding to the first collector electrode 21 and the bus electrode 5 is not covered by the insulating block 3, while the position corresponding to the second collector electrode 22 and the bus electrode 5 is covered by the insulating block 3. This bus electrode 5 is used to collect the current from the first collector electrode 21. (Refer to...) Figure 4 and Figure 7 The width of the bus electrode 5 is W5, and the direction of the width of the bus electrode 5 is perpendicular to the extension direction of the bus electrode 5. For example, Figure 5The bus electrode 5, marked W5, extends along the second direction, and its width is along the first direction. Along the first direction L3: the length of the first part is D1, where 3 ≤ D1 / W5 ≤ 15. If D1 / W5 is too large, there may be a problem with poor current collection; if D1 / W5 is too small, there may be a risk of short circuit to the bus electrode 5. Therefore, if D1 / W5 is within the above range, the current collection effect is good, and the short circuit risk is low.

[0087] For example, D1 / W5 can be 3, 4, 56, 7, 8, 9, 10, 11, 12, 13, 14, 15.

[0088] It should be noted that the bus electrode 5 can be a standalone component or a thickened section of the collector electrode. When the bus electrode 5 is a thickened section of the collector electrode, the thickened section is thicker than the rest of the collector electrode. The bus electrode 5 can be a terminal wire (…). Figure 4 The inclined bus electrode marked 5 on the left side), the main grid ( Figure 4 The bus electrode marked W5), border lines, etc. In determining D1 / W5, it is not limited whether the bus electrode 5 corresponding to W5 covers the first part corresponding to D1, or whether it is electrically connected to the first part corresponding to D1. It is also not limited whether the bus electrode 5 corresponding to W5 covers the first part corresponding to D1, or whether it does not cover the first part corresponding to D1, or whether the collector electrode of the polarity of the bus electrode 5 corresponding to W5 and the first part corresponding to D1 are electrically connected. For example, the bus electrode 5 corresponding to W5 can be the width of the bus electrode 5 electrically connected to the first collector electrode, and the first part corresponding to D1 can be the length of at least the first part of the first collector electrode covered by the insulating block, or the first part corresponding to D1 can be the length of at least the first part of the second collector electrode covered by the insulating block. For example, the bus electrode 5 corresponding to W5 can be the width of the bus electrode 5 electrically connected to the second collector electrode, and the first part corresponding to D1 can be the length of at least the first part of the first collector electrode covered by the insulating block, or the first part corresponding to D1 can be the length of at least the first part of the second collector electrode covered by the insulating block. The above examples are all within the scope of protection of this application.

[0089] It should be noted that, for Figure 4 The back-contact solar cell shown has a busbar or main grid. In some embodiments, the back-contact solar cell has three terminal wires, which is relatively numerous and makes it more prone to short circuits. Therefore, the length of the first part of the current collector electrode of the opposite polarity below the terminal wire can be made longer to further reduce the risk of short circuits at this point. Figure 4In the back contact cell shown with a main grid or busbar electrode, the busbar electrode 5 spans multiple current collector electrodes along the second direction, forms an electrical connection with a current collector electrode of one polarity, and is in direct contact with the insulating block 3 on the current collector electrode of another polarity. The interconnecting member 6 is first electrically connected to a portion of the interconnecting part 4 and is disposed on the busbar electrode 5. The interconnecting member 6 is not in direct contact with the insulating block 3.

[0090] In some possible embodiments, along the thickness direction L1 of the battery body, the height difference between the surface of the busbar electrode away from the battery body and the surface of the adjacent insulating block away from the battery body is less than or equal to 5 μm. In this application, by reducing the height of at least the first portion covered under the insulating block in the current collector electrode, the risk of short circuit can be significantly reduced. Therefore, when the height difference between the surface of the busbar electrode away from the battery body and the surface of the adjacent insulating block away from the battery body is less than or equal to 5 μm along the thickness direction L1 of the battery body, there is essentially no risk of short circuit, and the height difference between the busbar electrode and the insulating block is not too large, resulting in a lower risk of microcracks introduced into the photovoltaic module.

[0091] For example, along the thickness direction L1 of the battery body: the height difference between the surface of the bus electrode away from the battery body and the surface of the adjacent insulating block away from the battery body can be 5μm, 4.8μm, 4.5μm, 3.7μm, 3.5μm, 3μm, 2.8μm, 2.5μm, 2.1μm, 2μm, 1.6μm, 1.5μm, 1μm, 0.7μm, 0.5μm, 0.2μm, 0.1μm, 0.05μm, or 0.01μm.

[0092] In some possible embodiments, refer to Figure 3 The back contact cell further includes: an interconnect portion 4, which spans at least one current collector electrode of one polarity along a second direction and forms an electrical connection with the current collector electrode of that polarity; an insulating block 3 covers the extension of the interconnect portion 4 to a current collector electrode of another polarity adjacent to the interconnect portion 4 along the second direction. The back contact cell may not contain bus electrodes, or may have few bus electrodes; the back contact cell is a back contact cell without a main grid or without bus electrodes. For this back contact cell, the interconnect member 6 spans multiple current collector electrodes along the second direction, forms an electrical connection with the interconnect portion 4 on the current collector electrode of one polarity, and directly contacts the insulating block 3 on the current collector electrode of another polarity.

[0093] For example, Figure 3 In the middle, the interconnect 6 closest to L2 is electrically connected to the interconnect 4 which is electrically connected to the second collector electrode 22. The position through which the interconnect 6 passes in the first collector electrode 21 closest to L2 is covered by an insulating block 3, which then contacts the interconnect 6 to prevent the first collector electrode 21 from contacting the interconnect 6 and short-circuiting.

[0094] SEM refers to a scanning electron microscope image. In some possible embodiments, refer to... Figure 8 Within the same current collector electrode: the surface roughness of the first portion 23, which is farther from the battery body, is greater than the surface roughness of the second portion 24, which is farther from the battery body. That is, within the same current collector electrode: the surface of at least the first portion 23 covered by the insulating block, which is farther from the battery body, is rougher, and the specific surface area of ​​the surface of at least the first portion 23 covered by the insulating block, which is farther from the battery body, is larger, increasing the contact area between the first portion and the insulating block, and further reducing the risk of short circuit.

[0095] It should be noted that the surface roughness mentioned in this application can be the difference between the highest point (peak) and the lowest point (valley) within a defined area (e.g., 250 μm × 250 μm, 250 μm × 280 μm, 280 μm × 280 μm, 300 μm × 280 μm, 300 μm × 300 μm, etc.), or it can be determined according to other relevant methods. The specific method for determining surface roughness is not limited. The size of the defined area is not limited. The difference between the surface roughness of the first part 23 (far from the battery body) and the surface roughness of the second part 24 (far from the battery body) is also not limited.

[0096] Figure 9 This is a partial 3D microscope top view of a current collector electrode. In some possible embodiments, refer to... Figures 6 to 9 Within the same collector electrode: along the first direction L3, the undulation of the contour line of the first portion 23 is less than the undulation of the contour line of the second portion 24. Here, undulation refers to the difference between the highest and lowest points within a defined length of the contour line. That is, within the same collector electrode: along the first direction, at least the first portion 23 covered by the insulating block has a straighter contour line, and its probability of penetrating or being adjacent to the insulating block is lower, further reducing the risk of short circuits. The defined length is not limited here.

[0097] In some possible embodiments, refer to Figure 10 , Figure 10 The first part is a cross-sectional SEM image. Along the second direction L2, the surface of the first part away from the battery body is undulating, which means there is an uneven phenomenon. The first part has at least two peaks (for example, the position corresponding to 231, and the low point in between). The peaks here can increase the contact area with the insulating block, increase reliability, and reduce the possibility of local excessively high spikes caused by setting only one peak at the center position, further reducing the risk of short circuit.

[0098] In some possible embodiments, refer to Figure 10Along the second direction L2, the first part has at least two peaks, and the difference H9 between the highest and lowest points of the peaks is greater than or equal to 0.3 micrometers. This can further increase the contact area with the insulating block and increase reliability. If the difference H9 is too small, the surface undulation is small, which is not conducive to increasing the contact area with the insulating adhesive and reduces reliability.

[0099] For example, the difference H9 can be 0.3 micrometers, 0.35 micrometers, 0.4 micrometers, 0.41 micrometers, 0.43 micrometers, 0.45 micrometers, 0.48 micrometers, or 0.5 micrometers.

[0100] This can be the maximum, minimum, or arithmetic mean of the difference between the highest and lowest points of a wave peak within a certain range; no specific limitation is made. The area or length of this range is also not limited.

[0101] In some possible embodiments, refer to Figure 2 and Figure 8 Along the first direction L3, the surface of the second part 24 away from the battery body has a wave-like undulation. The difference H8 between the highest and lowest points of the wave-like undulation is greater than or equal to 0.5 micrometers. Since the undulation has a relatively large specific surface area, it can increase the bonding force with the interconnection part.

[0102] For example, the difference H8 can be 0.5 micrometers, 0.55 micrometers, 0.6 micrometers, 0.61 micrometers, 0.63 micrometers, 0.65 micrometers, 0.68 micrometers, or 0.7 micrometers.

[0103] This can be the maximum, minimum, or arithmetic mean of the difference between the highest and lowest points within a certain range; there are no specific limitations on this. The area or length of this range is also not limited.

[0104] In some possible embodiments, refer to Figure 10 Along the second direction L2, the first part includes an edge portion 231 located at the edge and a middle portion 232 located between the two edge portions 231. The height of the middle portion 232 is lower than the height of the edge portions 231. In the first part, the closer to the middle along the second direction L2, the greater the probability of conductive structures such as interconnects and bus electrodes electrically connected to the opposite-polar collector electrode passing through. Therefore, the lower height of the middle portion 232 between the two edge portions 231 further reduces the risk of short circuits. In addition, the relatively high edge portion 231 also takes into account the current collection effect. At the same time, it increases the contact area between the first part and the insulating block, improves the bonding force between the first part and the insulating block, prevents the insulating block from peeling off, and improves the reliability of the component.

[0105] In some possible embodiments, refer to Figure 11 and Figure 12The first surface of the battery body includes alternating first conductive regions 16 and second conductive regions 17 along a second direction L2, meaning that along the second direction L2, one first conductive region 16 is followed by one second conductive region 17, and then another first conductive region 16. A first collector electrode 21 is disposed in the first conductive region 16, and a second collector electrode 22 is disposed in the second conductive region 17. The width of the second conductive region along the second direction is greater than the width of the first conductive region along the second direction. Specifically, the second conductive region can be a P-type conductive region, and its conductivity type is opposite to that of the silicon substrate; here, it is a minority carrier collection region, and its wider width ensures minority carrier collection.

[0106] Figure 11 In this configuration, the first conductive region 16 is further away from the second surface (light-facing surface) of the battery body than the second conductive region 17, or in other words, the first conductive region 16 is higher. The first conductive region can be an N-type conductive region, and the second conductive region can be a P-type conductive region. Figure 11 In this design, the height of the first portion of the second collector electrode 22 is greater than the height of the first portion of the first collector electrode 21. Specifically, the first conductive region 16 is higher, so it is closer to the insulating block and conductive structures such as interconnects, bus electrodes, and interconnects electrically connected to the second collector electrode than the second conductive region 17. Furthermore, this region will preferentially bear stress during string soldering or lamination at the component end, further increasing the risk of short circuits. Therefore, in this application, the height of the first portion of the first collector electrode 21 located on the first conductive region 16 is lower, thereby reducing the risk of short circuits caused by the first portion of the first collector electrode 21 penetrating or being adjacent to the insulating block, and also reducing risks such as microcracks introduced during lamination. The specific value of the height difference between the two is not limited.

[0107] It should be noted that the second collector electrode 22 here can be a P-type collector electrode. For details, refer to... Figure 11 The battery body may include: a semiconductor substrate 7, a second doped layer 8, a second doped layer 9, and a surface passivation layer 10. The first doped layer 8 corresponds at least in position to the first conductive region 16, and a first current collector 21 is disposed on the first doped layer 8. The second doped layer 9 corresponds in position to the second conductive region 17, and a second current collector 22 is disposed on the second doped layer 9. Therefore, the second doped layer 9 can be a P-type doped layer. The doping concentration of a P-type doped layer is typically lower than that of an N-type doped layer. In this application... Figure 11 In the middle, the first part of the second current collector is higher, which can compensate for the imbalance caused by the doping concentration of the P-type doped layer and the N-type doped layer, and further improve the performance of the back contact cell.

[0108] The semiconductor substrate 7 here can be N-type or P-type single-crystal silicon, providing long-lived charge carriers. The P-type doped layer can contain one or more elements from Group IIIA (e.g., boron). The N-type doped layer can contain one or more elements from Group VA (e.g., phosphorus). The materials of the N-type and P-type doped layers can include any semiconductor material such as silicon, germanium silicon, germanium, or gallium arsenide. In terms of the arrangement of matter, the crystal phase of the doped layer can be amorphous, microcrystalline, nanocrystalline, single-crystal, or polycrystalline. The materials of the N-type and P-type doped layers can be the same or different. For example, the materials of both the N-type and P-type doped layers can include doped polycrystalline silicon. Another example: the material of the P-type doped layer can include doped polycrystalline silicon, and the material of the N-type doped layer can include at least one of doped amorphous silicon, doped microcrystalline silicon, and doped nanocrystalline silicon. The P-type doped layer can be obtained by in-situ doping on the surface of the semiconductor substrate or by deposition on the surface of the semiconductor substrate. Similarly, the N-type doped layer can be obtained by in-situ doping on the surface of the semiconductor substrate or by deposition on the surface of the semiconductor substrate. The material of the surface passivation layer can be selected from alumina, silicon nitride, etc. In some possible embodiments, the battery body may also include a tunneling oxide layer 11, located between the first doped layer and the semiconductor substrate, and between the second doped layer and the semiconductor substrate. The material of the tunneling oxide layer 11 can be selected from silicon oxide, etc.

[0109] In some possible embodiments, refer to Figure 11 The first conductive region 16 is further away from the second surface (light-facing surface) of the battery body than the second conductive region 17. In other words, based on the higher first conductive region 16, the height of the second part of the second current collector 22 is greater than the height of the second part of the first current collector. Similarly, when the second current collector is a P-type current collector, it can compensate for the imbalance caused by the doping concentration of the P-type doped layer and the N-type doped layer, further improve the performance of the back contact cell, and reduce the height difference of the structure on the first conductive region and the second conductive region, which can reduce the risk of microcracks caused during the lamination process.

[0110] In some possible embodiments, the first conductive region 16 is further away from the second surface (light-facing surface) of the battery body than the second conductive region 17. In other words, given that the first conductive region 16 is higher, the height of the insulating block on the second current collector 22 is greater than the height of the insulating block on the first current collector electrode. Specifically, the higher first conductive region 16 and the lower insulating block on the first current collector electrode can reduce the height difference between the structures on the first and second conductive regions, thereby reducing the risk of microcracks and other defects during the lamination process.

[0111] It should be noted that, Figure 11The diagram shows a back-contact hybrid solar cell. The structure on the first conductive region 16 consists of an inner extension layer 12, a tunneling oxide layer 11, and a first doped layer 8, in sequence. The inner extension layer 12 and the first doped layer have the same doping type and contain the same doping elements. The structure on the second conductive region 17 consists of an intrinsic amorphous silicon layer 13 and a second doped layer 9, in sequence. The intrinsic amorphous silicon layer 13 and the second doped layer 9 extend from the second conductive region 17 and cover a portion of the first doped layer 8, with the first doped layer 8 partially exposed. A transparent conductive layer 15 covers the side of the first doped layer 8 and the second doped layer 9 away from the semiconductor substrate 7 and is disconnected in a portion of the first conductive region to avoid short circuits. Here, the first doped layer can be an N-type doped polycrystalline silicon layer, and the second doped layer can be a P-type doped amorphous and / or microcrystalline silicon layer; no specific limitation is made.

[0112] Figure 12 In this configuration, the second conductive region 17 is further away from the second surface (light-facing surface) of the battery body than the first conductive region 16, or in other words, the second conductive region 17 is higher. The first conductive region can be an N-type conductive region, and the second conductive region can be a P-type conductive region. Figure 12 In this design, the height of the first portion of the first collector electrode 21 is greater than the height of the first portion of the second collector electrode 22. Specifically, the second conductive region 17 is higher, so it is closer to the insulating block and conductive structures such as interconnects, bus electrodes, and interconnects electrically connected to the first collector electrode than the first conductive region 16. Furthermore, this region preferentially bears stress during string soldering or lamination at the component end, further increasing the risk of short circuits. Therefore, in this application, the height of the first portion of the second collector electrode 22 located on the second conductive region 17 is lower, thereby reducing the risk of short circuits caused by the first portion of the second collector electrode 22 penetrating or being adjacent to the insulating block. The specific value of the height difference between the two is not limited. It should be noted that the second collector electrode 22 here can be a P-type collector electrode.

[0113] Figure 12 The semiconductor substrate 7, tunneling oxide layer 11, first doped layer, and second doped layer, etc., can be referred to Figure 11 The corresponding record in [the text].

[0114] In some possible embodiments, refer to Figure 12 The second conductive region 17 is further away from the second surface (light-facing surface) of the battery body than the first conductive region 16. In other words, the height of the second part of the first current collector electrode is greater than the height of the second part of the second current collector electrode, which can reduce the risk of microcracks, etc.

[0115] In some possible embodiments, the second conductive region 17 is further away from the second surface (light-facing surface) of the battery body than the first conductive region 16. In other words, given that the second conductive region 17 is higher, the height of the insulating block on the first current collector electrode is greater than the height of the insulating block on the second current collector electrode. Specifically, the higher second conductive region 17 and the lower insulating block on the second current collector electrode can reduce the height difference between the structures on the first and second conductive regions, thereby reducing the risk of microcracks and other problems during the lamination process.

[0116] It should be noted that, Figure 12 The image shows a back-contact TBC (tunneling oxide passivated back contact) solar cell. The structure on the first conductive region 16 consists of a tunneling oxide layer 11 and a first doped layer 8, respectively; the structure on the second conductive region 17 consists of a tunneling oxide layer 11 and a second doped layer 9, respectively. A spacer region 14 is provided between adjacent first conductive regions 16 and second conductive regions 17 to prevent short circuits. Here, the first doped layer can be an N-type doped polycrystalline silicon layer, and the second doped layer can be a P-type doped polycrystalline silicon layer; there is no specific limitation on this.

[0117] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the number of second current collector electrodes disposed on a second conductive region is equal to the number of first current collector electrodes disposed on a first conductive region. The second conductive region is a P-type conductive region. The width of the first portion of the second current collector electrode 22 on such a second conductive region is greater than the width of the first portion of the first current collector electrode 21 on such a first conductive region. This not only further reduces the short-circuit risk of the first current collector electrode 21, but also increases the contact area between the first portion of the second current collector electrode 22 and the second doped layer, thereby improving the carrier transport capability in the second doped layer.

[0118] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 The number of second current collectors on a second conductive region (as shown in the back contact cell) is equal to the number of first current collectors on a first conductive region. The second conductive region is a P-type conductive region. The width of the second portion of the second current collector on such a second conductive region is greater than the width of the second portion of the first current collector on such a first conductive region. Similarly, when the second current collector is a P-type current collector, the imbalance caused by the doping concentration of the P-type doped layer and the N-type doped layer can be compensated, the contact area with the conductive region can be increased, the bulk resistance of the P-type current collector can be reduced, and the performance of the back contact cell can be further improved.

[0119] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the number of second current collector electrodes disposed on a second conductive region is greater than the number of first current collector electrodes disposed on a first conductive region. The second conductive region is a P-type conductive region. For example, the second current collector electrodes disposed on a second conductive region can be two or more, which helps to shorten the carrier transport path and reduce recombination, thereby increasing the collection efficiency and transport capability of carriers in the second doped layer. In such a second conductive region, the width of the first part of a second current collector electrode 22 is smaller than the width of the first part of the first current collector electrode 21 on the first conductive region. Since there are more second current collector electrodes on a second conductive region, the total width of the first part of the second current collector electrodes on a second conductive region is larger, which also increases the contact area between the first part of the second current collector electrode 22 and the second doped layer, improving the carrier transport capability in the second doped layer. At the same time, the width of the first part of a single second current collector electrode is smaller, balancing cost and collection effect.

[0120] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the number of second current collector electrodes disposed on a second conductive region is greater than the number of first current collector electrodes disposed on a first conductive region. The second conductive region is a P-type conductive region. For example, the second current collector electrodes disposed on a second conductive region can be two or more, which helps to shorten the carrier transport path and reduce recombination, thereby increasing the collection efficiency and transport capability of carriers in the second doped layer. In such a second conductive region, the width of the second part of a second current collector electrode 22 is smaller than the width of the second part of the first current collector electrode 21 on the first conductive region. Since there are more second current collector electrodes on a second conductive region, the total width of the second part of the second current collector electrodes on a second conductive region is larger, which also increases the contact area between the second part of the second current collector electrode 22 and the second doped layer, improving the carrier transport capability in the second doped layer. At the same time, the width of the second part of a single second current collector electrode is smaller, balancing cost and collection effect.

[0121] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12(As shown in the back contact cell), the difference between the width of the second part of the second collector grid line and the width of the first part is W6, and the difference between the width of the second part of the first collector electrode and the width of the first part is W7. W6 > W7, which means that the width of the second part of the second collector grid line is larger. Since the second part occupies the main part of the length of the collector electrode, the width of the second part of the second collector grid line is larger, and the contact area with the second conductive region is larger, which also improves the carrier transport capability in the second doped layer.

[0122] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the height difference between the second part of the second collector grid line and the first part is H4, and the height difference between the second part of the first collector electrode and the first part is H5. H4 > H5, which means that the height of the second part of the second collector grid line is greater. Since the second part accounts for the main part of the length of the collector electrode, the greater height of the second part of the second collector grid line also improves the carrier transport capability in the second doped layer and reduces the imbalance problem caused by the doping concentration in the P-type conductive region.

[0123] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the aspect ratio of the first part of the second collector grid line is greater than that of the first part of the first collector grid line. The first part of the second collector grid line has less shading and lower resistance, resulting in less energy loss during current transmission and thus improving the carrier transport capability in the second doped layer.

[0124] In some possible embodiments, for all back-contact battery cells (e.g., may include...) Figure 11 and Figure 12 (As shown in the back contact cell), the aspect ratio of the second part of the second collector grid line is greater than that of the second part of the first collector grid line. The second part of the second collector grid line has less shading and lower resistance, resulting in less energy loss during current transmission and thus improving the carrier transport capability in the second doped layer.

[0125] In some possible embodiments, refer to Figure 4 ( Figure 4 As shown in the dashed box in the upper left corner, at least one current collector electrode near the edge of the solar cell is disconnected. This further reduces the risk of short circuits near the edge. Specifically, it means that conductive structures such as interconnects that would electrically connect to current collector electrodes of the opposite polarity pass through the cell. These interconnects would cross the edges or edges of two adjacent solar cells. Figure 4The interconnecting element 6 is shown in the diagram. Whether or not an insulating block is placed at the disconnected location of the disconnected collector electrode is not limited. For example, Figure 3 In the middle, the disconnected collector electrode has an insulating block 3 at the disconnection position to further reduce the risk of short circuit.

[0126] In some possible embodiments, the current collector electrode is a base metal electrode, which can reduce costs. Here, "base metal electrode" means that the mass percentage of base metal elements in the current collector electrode can be greater than or equal to 50%. The specific material of the base metal electrode is not limited. For example, the material of the base metal electrode is selected from at least one of: copper (Cu), nickel (Ni), chromium (Cr), lead (Pb), aluminum (Al), silver-clad copper, and silver-clad copper containing silver powder. Firstly, the above materials have good conductivity; secondly, the cost of the above materials is low, which can reduce the cost of the electrode; and thirdly, the above materials are formed using low-temperature processes, avoiding the penetration of the surface passivation layer into the semiconductor substrate, reducing recombination, and avoiding the introduction of thermal effects into the back contact cell.

[0127] In some possible embodiments, refer to Figures 11 to 13 The battery body includes a doped layer, and the current collector electrode is electrically connected to the doped layer. The doped layer near the edge 18 of the back contact cell is an edge doped layer. The current collector electrode on the edge doped layer is closer to the interior of the back contact cell. Specifically, during the printing of the current collector electrode, the closer the current collector electrode on the edge doped layer is to the edge of the cell, the greater the tension at the position corresponding to the current collector electrode on the edge doped layer in the screen, which makes it easier to wear and reduces the life of the screen. In this application, the current collector electrode on the edge doped layer is closer to the interior of the back contact cell, which can appropriately reduce screen wear and extend the life of the screen.

[0128] In some possible embodiments, refer to Figures 11 to 13 The battery body includes a doped layer, and the current collector electrode is electrically connected to the doped layer. The doped layer near the edge 18 of the back contact cell is an edge doped layer, and the width of the edge doped layer is smaller than the width of the doped layer inside the back contact cell. Specifically, as mentioned above, since the current collector electrode on the edge doped layer is located further inward, the carrier transport path outside the current collector electrode on the edge doped layer will be longer. If the width of the edge doped layer is too wide, the carrier transport path will be longer, resulting in greater losses and more recombination. Therefore, in this application, the width of the edge doped layer is smaller, which can reduce recombination. Here, the doped layer inside the back contact cell refers to the doped layer inside the back contact cell that is further inward than the edge doped layer, and the doping type can be the same as or different from that of the edge doped layer.

[0129] It should be noted that the back contact cell edge line refers to at least a portion of the outline of the back contact cell.

[0130] This application also provides a printing steel plate, as shown in the reference. Figure 14 The printed steel plate includes several printed areas 19 extending along a first direction L3 and arranged sequentially along a second direction L2. Each printed area 19 includes a third portion 191 and a fourth portion 192 continuously arranged along the first direction L3. The height of the third portion 191 is H6, and the height of the fourth portion 192 is H7, where H6 < H7. This printed steel plate can be used to print any of the aforementioned current collector electrodes. In the current collector electrodes printed by this plate, the third portion 191 corresponds to the aforementioned first portion, and the fourth portion 192 corresponds to the aforementioned second portion. The third portion is lower, so the printed first portion is lower, reducing the risk of short circuits. The fourth portion is higher, so the printed second portion is higher, balancing current collection performance.

[0131] In some possible embodiments, refer to Figure 14 Part 3, section 191, does not have printed steel wires, while Part 4, section 192, has parallel distributed wires (such as...). Figure 14 The printed steel wires 193 are distributed parallel to the second direction L2. Since no printed steel wires are provided in the third part, the surface of the resulting first part is smoother, with less surface roughness and less undulation in the edge contour, further reducing the risk of short circuits. Traditional screen printing stencils have intersecting wires, which results in higher printing spikes and more undulating mesh marks when printing current collector electrodes. Compared to stencils with intersecting printed wires, the fourth part 192 in this application does not have intersecting printed wires, resulting in smaller printing spikes and a smoother surface in the resulting second part, saving costs and improving battery performance.

[0132] In some possible embodiments, refer to Figure 14 The width of the printed steel wire 193 is 8-15μm. This suitable line width results in a relatively smooth surface morphology of the printed current collector electrode with minimal edge contour undulation. This not only reduces the risk of short circuits but also saves costs and improves battery performance. Furthermore, the width of the printed steel wire 193 is 8-14μm, and the direction of its width is perpendicular to its extension direction. For example, the width of the printed steel wire 193 can be 8μm, 8.5μm, 9μm, 9.5μm, 10μm, 10.5μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.5μm, 14μm, 14.5μm, or 15μm.

[0133] In some possible embodiments, refer to Figure 14The spacing between adjacent printed steel wires 193 is less than or equal to 80 μm, ensuring a good shaping effect on the current collector electrode without being too large. A further spacing can be less than or equal to 70 μm. For example, the spacing between adjacent printed steel wires 193 can be 1 μm, 5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, 10 μm, 10.5 μm, 11 μm, 11.5 μm, 12 μm, 12.5 μm, 13 μm, 13.5 μm, 14 μm, 14.5 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, or 80 μm.

[0134] It should be noted that, Figure 14 In the middle, the dashed box covering the third part 191 shows the printing area 20 corresponding to the insulating block. This box is not included in the actual printed steel plate.

[0135] In some possible embodiments, parallel printed wires 193 are provided in both the third portion 191 and the fourth portion 192. Crossed printed wires would result in higher printing spikes. Compared to printing screens with crossed printed wires, neither the third portion 191 nor the fourth portion 192 in this application has crossed printed wires. Therefore, the printing spikes in the first and second portions are smaller, and the surfaces are smoother. This not only reduces the risk of short circuits but also saves costs and improves battery performance. The number of printed wires 193 per unit area in the third portion 191 is less than the number of printed wires 193 in the fourth portion 192. The fewer the number of printed wires 193 per unit area, the smoother the surface of the printed structure and the smaller the undulation of the edge contour. Therefore, in the same current collector electrode printed in this application, the surface of the first portion is smoother, and the edge contour has less undulation, further reducing the risk of short circuits. The size of the unit area is not limited here. For example, 1μm × 1μm, etc.

[0136] In some possible embodiments, the width of the third portion 191 is smaller than the width of the fourth portion 192, which can also reduce the short-circuit risk of back-contact cells or photovoltaic modules while taking into account the current collection effect.

[0137] In some possible embodiments, the length of the third portion 191 is less than the length of the fourth portion 192, which can also reduce the short-circuit risk of back-contact cells or photovoltaic modules while taking into account the current collection effect.

[0138] It should be noted that the printing plate of this application can be used to print any of the aforementioned current collectors, with one printing area corresponding to one current collector. In the same current collector obtained by the printing plate, the third part 191 corresponds to the aforementioned first part, and the fourth part 192 corresponds to the aforementioned second part. The relative relationship of the dimensions of the third part 191 and the fourth part 192 can be referred to the relative relationship of the dimensions of the aforementioned first part and the second part, and have the same or similar beneficial effects. To avoid repetition, it will not be described again.

[0139] This application also provides a photovoltaic module, as shown in the reference. Figure 4 The photovoltaic module also includes: an interconnect 6 and a plurality of the aforementioned back-contact solar cells, the interconnect 6 extending along a second direction L2. The interconnect 6 is generally oriented along the second direction L2, but local bending in other directions is permitted. Along the second direction L2, the interconnect 6 is electrically connected to a current collector of one polarity, and along the second direction L2, the interconnect 6 crosses a current collector of another polarity, with an insulating block 3 disposed between the interconnect 6 and the current collector of the other polarity. For example, Figure 4 In this configuration, the interconnect 6, located near L2, spans multiple adjacent collector electrodes. Among these adjacent collector electrodes, the first collector electrode 21 is electrically connected to the position corresponding to the interconnect 6, and the position corresponding to the second collector electrode 22 is covered by an insulating block 3. The interconnect 6 is used to collect the current from the first collector electrode 21. Because in this application, the height H1 of at least the first portion covered by the insulating block 3 in a single collector electrode is smaller, the short-circuit risk of the photovoltaic module is reduced.

[0140] In some possible embodiments, refer to Figure 4 and Figure 6 The width of interconnect 6 is W8, and the direction of the width of interconnect 6 is perpendicular to its extension direction and parallel to the first direction. The length of the first part is D1, where 0.1 ≤ W8 / D1 ≤ 1. If W8 / D1 is too small, there may be a problem with poor current collection; if W8 / D1 is too large, there may be a risk of short circuit due to the interconnect. Therefore, W8 / D1 is within the above range, resulting in good current collection and low short circuit risk. It should be noted that interconnect 6 can be a solder strip, conductive backplate, etc.

[0141] For example, W8 / D1 can be 0.1, 0.15, 0.3, 0.5, 0.67, 0.7, 0.8, 0.9, or 1.

[0142] It should be noted that the interconnecting components are connected via interconnecting parts to connect multiple back-contact battery cells in series. For example, in the case of a "back-contact battery without a main grid," the interconnecting parts can be welded portions respectively disposed on the first and second current collector electrodes, and the interconnecting components are connected via these welded portions. As another example, in the case of a "back-contact battery with a main grid," the battery also includes a bus electrode, such as... Figure 4 As shown, the interconnect components are connected via interconnect parts and bus electrodes.

[0143] It should be noted that the same content of the back contact solar cell, printed steel plate and photovoltaic module provided in this application can be referred to each other and can achieve the same or similar beneficial effects. In order to avoid repetition, it will not be described again.

[0144] The following specific examples will further explain this application.

[0145] Example 1 Reference Figure 11 The battery body, along its thickness direction L1, includes a first surface and a second surface opposite to each other, wherein the first surface is its backlight surface and the second surface is its light-facing surface. The first surface includes a first conductive region 16 and a second conductive region 17 sequentially disposed along the second direction L2, wherein the first conductive region 16 is further away from the second surface than the second conductive region 17. The first doped layer 8 is an N-type doped polycrystalline silicon layer, and the second doped layer 9 is a P-type doped amorphous silicon layer. The first doped layer 8 is disposed on the first conductive region 16, the first current collector 21 is disposed on the first doped layer 8, the second doped layer 9 is disposed on the second conductive region 17, and the second current collector 22 is disposed on the second doped layer 9.

[0146] Figure 11 Both the first collector electrode 21 and the second collector electrode adopt Figure 14 The printed steel plate shown has a height of H6 for the third part and H7 for the fourth part, where H6 < H7. The third part corresponds to the first part of the first and second collector electrodes, and the fourth part corresponds to the second part of the first and second collector electrodes. The height H1 of the first collector electrode is approximately 3.2 μm, and the height H1 of the first part of the second collector electrode is approximately 4.7 μm. The height H2 of the second part of the first collector electrode is approximately 8.5 μm, and the height H2 of the second part of the second collector electrode is approximately 12.7 μm. The width W1 of the first collector electrode is approximately 53 μm, and the width W1 of the first part of the second collector electrode is approximately 65 μm. The width W2 of the second part of the first collector electrode is approximately 54 μm, and the width W2 of the second part of the second collector electrode is approximately 72 μm.

[0147] The electrical parameters of the multiple back-contact solar cells shown in Example 1 were measured, and the corresponding arithmetic mean was calculated. The calculation results are shown in Table 1 below.

[0148] Of the 10,000 photovoltaic modules prepared using the back-contact solar cells of Example 1, 145 modules experienced short circuits, resulting in a short circuit rate of 145 / 10,000 = 1.45%.

[0149] Comparative Example The only difference between the comparative example and Example 1 is that the comparative example uses a screen printing stencil with intersecting wires; in other words, the comparative example does not distinguish between the first and second parts of the current collector electrode, and the height of each part of the current collector electrode is approximately equal. The paste used for the first and second current collector electrodes in both the comparative example and Example 1 is the same. In the comparative example, the height of the first current collector electrode is approximately 7.6 μm, and the height of the second current collector electrode is approximately 11.2 μm. The width of the first current collector electrode is approximately 54 μm, and the width of the second current collector electrode is approximately 78 μm.

[0150] The electrical parameters of the multiple back-contact solar cells shown in the comparative example were measured, and the corresponding arithmetic mean was calculated. The calculation results are shown in Table 1 below.

[0151] Of the 10,000 photovoltaic modules prepared using the comparative back-contact solar cells, 1,139 modules experienced short circuits, resulting in a short circuit rate of 1,139 / 10,000 = 11.39%.

[0152]

[0153] By comparing Example 1 and the comparative example above, it can be concluded that, with the same paste material, in Example 1, by reducing the height of at least the first part of the electrode, which is covered by the insulating block and poses a short-circuit risk, the height of the printed spikes in the first part is effectively reduced, thereby significantly reducing the short-circuit risk caused by the printed spikes penetrating or adjacent to the insulating adhesive. Furthermore, with the same paste material, a comparison of the effects of screen printing and stencil printing processes shows that stencil printing results in better grid line uniformity and lower flatness, not only reducing the bulk resistance of the grid lines but also achieving precise linewidth control. The stencil printing process, while reducing the generation of printed spikes and further suppressing the short-circuit risk, also improves electrical parameters such as the series resistance of the battery, ultimately leading to an increase in power generation efficiency.

[0154] It should be noted that the various embodiments provided in this application can be used individually or in combination without contradiction, and all are within the protection scope of this application.

[0155] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0156] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims. All of these forms are within the protection scope of this application.

Claims

1. A back contact battery cell, characterized in that, include: The battery body, along its thickness direction, includes opposing first and second surfaces; A plurality of current collector electrodes are disposed on the first surface of the battery body and extend along a first direction; The plurality of current collector electrodes includes: a first current collector electrode and a second current collector electrode, which are distributed sequentially along a second direction; the first direction intersects the second direction; An insulating block is located in a local area on the side away from the battery body of a current collector electrode that is continuously arranged along a first direction. In the same current collector electrode: the height of at least the first part covered by the insulating block is H1, and the height of at least the second part not covered by the insulating block is H2, where H1 < H2.

2. The back contact battery cell according to claim 1, characterized in that, In the same current collector electrode: along the second direction, the width of at least a first portion covered by the insulating block is W1, and the width of at least a second portion not covered by the insulating block is W2, where W1 < W2; and / or, The difference between W2 and W1 is greater than or equal to 1 μm and less than or equal to 50 μm, and / or the ratio of W2 to W1 is between 1.1 and 3.

3. The back contact battery cell according to claim 1, characterized in that, In the same current collector electrode: the aspect ratio of the second part is greater than that of the first part.

4. The back contact battery cell according to claim 1, characterized in that, The height of the insulating block is H3, where H3 > H1; The difference between H3 and H1 is greater than or equal to 5 μm, and / or the ratio of H3 to H1 is between 1.2 and 15.

5. The back contact battery cell according to claim 1, characterized in that, The ratio of H2 to H1 is 1.1 to 5; and / or the difference between H2 and H1 is less than or equal to 30 μm.

6. The back contact battery cell according to claim 1, characterized in that, Along the second direction, the width of the first part is W1, and the width of the insulating block is W3, where W1 < W3; The difference between W3 and W1 is 150 to 750 μm, and / or the ratio of W3 to W1 is 2 to 45.

7. The back contact battery cell according to claim 1, characterized in that, Along the first direction: the length of the first part is D1, and the length of the insulating block is D2; The ratio of D1 to D2 is between 0.3 and 3, and / or the absolute value of the difference between D1 and D2 is less than or equal to 4 mm.

8. The back contact battery cell according to claim 1, characterized in that, Also includes: An interconnect portion is located on the side of the current collector electrode away from the battery body; along the second direction, the interconnect portion spans at least two adjacent current collector electrodes, wherein one polarity current collector electrode is not covered by an insulating block at the position corresponding to the interconnect portion, forming an electrical connection, while the other polarity current collector electrode is covered by an insulating block at the position corresponding to the interconnect portion; along the first direction: the length of the first portion is D1, the width of the interconnect portion is W4, 0.5≤W4 / D1≤1.5; and / or, The back contact cell also includes: a bus electrode, located on the side of the current collector electrode away from the battery body; Along the second direction, the bus electrode spans at least two adjacent collector electrodes. Among the at least two adjacent collector electrodes, the position of the collector electrode of one polarity corresponding to the bus electrode is not covered by an insulating block, while the position of the collector electrode of the other polarity corresponding to the bus electrode is covered by an insulating block. Along the first direction: the width of the bus electrode is W5, the length of the first part is D1, and 3≤D1 / W5≤15.

9. The back contact battery cell according to claim 1, characterized in that, Also includes: An interconnect portion, along the second direction, spans at least one current collector electrode of one polarity and forms an electrical connection with the current collector electrode of the one polarity; an adjacent current collector electrode of another polarity is covered with an insulating block at the extension of the interconnect portion along the second direction.

10. The back contact battery cell according to claim 8, characterized in that, Along the thickness direction of the battery body: the height difference between the surface of the bus electrode away from the battery body and the surface of the adjacent insulating block away from the battery body is less than or equal to 5 μm.

11. The back contact battery cell according to claim 1, characterized in that, In the same current collector electrode: the surface roughness of the first portion away from the battery body is greater than the surface roughness of the second portion away from the battery body; and / or, In the same current collector electrode: along the first direction, the undulation of the contour line of the first part is less than the undulation of the contour line of the second part.

12. The back contact battery cell according to claim 1, characterized in that, Along the second direction, the surface of the first portion away from the battery body is undulating, and the first portion has at least two peaks; And / or, the first portion includes an edge portion located at the edge and a middle portion located between the two edge portions, the height of the middle portion being lower than the height of the edge portions; And / or, the difference between the highest and lowest points of the wave crest is greater than or equal to 0.3 micrometers.

13. The back contact battery cell according to claim 1, wherein along the first direction, the surface of the second portion away from the battery body has a wave-like undulation, and the difference between the highest point and the lowest point of the wave-like undulation is greater than or equal to 0.5 micrometers.

14. The back contact battery cell according to claim 1, characterized in that, The first surface includes: a first conductive region and a second conductive region arranged sequentially along the second direction; the first current collector electrode is disposed in the first conductive region; and the second current collector electrode is disposed in the second conductive region; the width of the second conductive region along the second direction is greater than the width of the first conductive region along the second direction. The number of second collector electrodes disposed on a second conductive region is equal to the number of first collector electrodes disposed on a first conductive region; the width of the first portion of the second collector electrode on the second conductive region is greater than the width of the first portion of the first collector electrode on the first conductive region; and / or, the width of the second portion of the second collector electrode on the second conductive region is greater than the width of the second portion of the first collector electrode on the first conductive region. Alternatively, the number of second collector electrodes disposed on a second conductive region is greater than the number of first collector electrodes disposed on a first conductive region; the width of the first portion of the second collector electrode on the second conductive region is less than the width of the first portion of the first collector electrode on the first conductive region; and / or, the width of the second portion of the second collector electrode on the second conductive region is less than the width of the second portion of the first collector electrode on the first conductive region.

15. The back contact battery cell according to claim 1, characterized in that, The first surface includes: a first conductive region and a second conductive region sequentially disposed along the second direction, the first current collector electrode being disposed in the first conductive region, and the second current collector electrode being disposed in the second conductive region; the battery body further includes a semiconductor substrate, and the conductivity type of the second conductive region is opposite to the conductivity type of the silicon substrate; The difference between the width of the second portion of the second collector electrode and the width of the first portion is W6, and the difference between the width of the second portion of the first collector electrode and the width of the first portion is W7, where W6 > W7. And / or, the height difference between the second portion of the second collector electrode and the height of the first portion is H4, and the height difference between the second portion of the first collector electrode and the height of the first portion is H5, where H4 > H5. And / or, The aspect ratio of the first portion of the second collector grid line is greater than that of the first portion of the first collector grid line; the aspect ratio of the second portion of the second collector grid line is greater than that of the second portion of the first collector grid line.

16. The back contact battery cell according to claim 1, characterized in that, The first surface includes: a first conductive region and a second conductive region arranged sequentially along the second direction, wherein the first current collecting electrode is disposed in the first conductive region and the second current collecting electrode is disposed in the second conductive region; The first conductive region is further away from the second surface than the second conductive region; the height of the first portion of the second current collector electrode is greater than the height of the first portion of the first current collector electrode; and / or, the height of the second portion of the second current collector electrode is greater than the height of the second portion of the first current collector electrode; and / or, the height of the insulating block on the second current collector electrode is greater than the height of the insulating block on the first current collector electrode; or... The second conductive region is further away from the second surface than the first conductive region; the height of the first portion of the first collector electrode is greater than the height of the first portion of the second collector electrode; and / or, the height of the second portion of the first collector electrode is greater than the height of the second portion of the second collector electrode; and / or, the height of the insulating block on the first collector electrode is greater than the height of the insulating block on the second collector electrode.

17. The back contact battery cell according to claim 1, characterized in that, At least one current collector electrode located near the edge of the solar cell is disconnected.

18. The back contact battery cell according to any one of claims 1 to 17, characterized in that, The current collector electrode is a base metal electrode; and / or, H1 is 2-20 μm, and / or H2 is 5-50 μm; In the same current collector electrode: the width of at least a first portion covered by the insulating block is W1, and the width of at least a second portion not covered by the insulating block is W2, where W1 is 20-100 μm, and / or W2 is 20-100 μm; and / or, The height of the insulating block is H3, where H3 can be 12-55 μm; and / or, The width of the insulating block is W3, where W3 is 300-800 μm; and / or, Along the first direction: the length of the first part is D1, the length of the insulating block is D2, D1 is 1-5mm, and / or, D2 is 1-5mm.

19. The back contact battery cell according to any one of claims 1 to 17, characterized in that, The battery body includes a doped layer, and the current collector electrode is electrically connected to the doped layer. The doped layer near the edge of the back contact cell is an edge doped layer, and the current collector on the edge doped layer is closer to the interior of the back contact cell, and / or the width of the edge doped layer is smaller than the width of the doped layer inside the back contact cell.

20. A printing steel plate, characterized in that, include: Several printing areas extending along a first direction and arranged sequentially along a second direction; The printing area includes a third portion and a fourth portion that are continuously arranged along a first direction; The height of the third part is H6, and the height of the fourth part is H7, where H6 < H7.

21. The printing plate according to claim 20, characterized in that, The third part does not have printing wires, while the fourth part has parallelly distributed printing wires; or, Both the third and fourth parts are provided with parallel printed steel wires, and the number of printed steel wires in the third part is less than the number of printed steel wires in the fourth part per unit area.

22. The printing plate according to claim 21, characterized in that, The width of the printed steel wire is 8-15 μm, and / or the spacing between adjacent printed steel wires is less than or equal to 80 μm.

23. A photovoltaic module, characterized in that, include: Interconnector and back contact battery cell as described in any one of claims 1 to 19; The interconnecting member extends along a second direction and is electrically connected to the interconnecting portion of a current collector of one polarity; and along the second direction, the interconnecting member spans a current collector of another polarity, with an insulating block disposed between the interconnecting member and the current collector of the other polarity.

24. The photovoltaic module according to claim 23, characterized in that, The width of the interconnect is W8, and the length of the first part is D1, where 0.1 ≤ W8 / D1 ≤ 1.

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