Battery module and laser grooving method

Abstract

The invention provides a battery module and a laser grooving method, and solves the problem of how to improve the reliability of a solar battery in the prior art. The battery module comprises: a substrate; the first electrode layer is positioned on one side of the substrate; the optical active layer is located on the side, away from the substrate, of the first electrode layer; the second electrode layer is located on the side, away from the substrate, of the optical active layer; wherein the battery module is provided with a first groove, the first groove penetrates through the second electrode layer and the optical active layer and exposes the first electrode layer, the first groove comprises a first sub-groove and a second sub-groove which are adjacently arranged in the direction close to the substrate, and the orthographic projection of the second sub-groove on the substrate is located in the orthographic projection range of the first sub-groove on the substrate.

Description

Technical Field

[0001] This application relates to the field of solar cell technology, specifically to a battery module and a laser grooving method. Background Technology

[0002] Perovskite solar cells have become a research hotspot in next-generation photovoltaic technology due to their high photoelectric conversion efficiency and low-cost solution preparation process. However, the reliability of solar cells in related technologies needs to be improved. Summary of the Invention

[0003] In view of this, the present application provides a battery module and a laser grooving method, which solves the problem of how to improve the reliability of solar cells in the prior art.

[0004] A first aspect of this application provides a battery module, comprising: a substrate; a first electrode layer located on one side of the substrate; a photoactive layer located on the side of the first electrode layer away from the substrate; and a second electrode layer located on the side of the photoactive layer away from the substrate; wherein the battery module has a first groove, the first groove penetrating the second electrode layer and the photoactive layer and exposing the first electrode layer, the first groove including a first sub-groove and a second sub-groove disposed adjacently along the direction close to the substrate, the orthographic projection of the second sub-groove on the substrate being located within the orthographic projection range of the first sub-groove on the substrate.

[0005] In conjunction with the first aspect, in some possible implementations, the depth of the first sub-groove is greater than or equal to the thickness of the second electrode layer; preferably, the first groove further includes a third sub-groove, the third sub-groove is adjacent to the second sub-groove and is located on the side of the second sub-groove closer to the substrate, and the orthographic projection of the third sub-groove on the substrate is within the orthographic projection range of the second sub-groove on the substrate; preferably, the distance between the interface of the second and third sub-grooves and the substrate is greater than or equal to the distance between the photoactive layer and the substrate.

[0006] In conjunction with the first aspect, in some possible implementations, the width of the first groove is greater than or equal to 30 micrometers and less than or equal to 50 micrometers; preferably, the second electrode layer includes a protrusion located at the opening of the first groove, the height of the protrusion being less than 200 nanometers; preferably, the battery module further includes a cover plate located on the side of the second electrode layer away from the substrate, the cover plate sealing the opening of the first groove; preferably, the battery module also has a second groove penetrating the photoactive layer and exposing the first electrode layer, the second electrode layer filling the second groove and contacting the first electrode layer; preferably, the battery module further includes a first transport layer located at the first electrode layer. Between the photoactive layer and the phototransfer layer, the first groove and the second groove respectively penetrate the first transport layer; and / or, the battery module further includes a second transport layer, which is located between the photoactive layer and the second electrode layer, and the first groove and the second groove respectively penetrate the second transport layer; preferably, the first transport layer includes a hole transport layer and the second transport layer includes an electron transport layer; preferably, the battery module also has a third groove, which penetrates the first electrode layer, and the orthographic projection of the third groove on the substrate is located on the side of the orthographic projection of the second groove on the substrate away from the orthographic projection of the first groove on the substrate, and the first transport layer fills the third groove; preferably, the material of the photoactive layer includes perovskite.

[0007] A second aspect of this application provides a laser grooving method, comprising: using a laser beam to scribing along at least three paths on the surface of a pre-placed substrate to form at least three scribing grooves; wherein, in a direction parallel to the pre-placed substrate, the at least three scribing grooves are arranged sequentially and connected, and at least two scribing grooves with adjacent preparation order are spaced apart.

[0008] In conjunction with the second aspect, in some possible implementations, at least three scribe lines include a first scribe line, a second scribe line, a third scribe line, and a fourth scribe line prepared sequentially, arranged in sequence; or, the first scribe line, the third scribe line, the fourth scribe line, and the second scribe line are arranged in sequence; preferably, the pre-placed substrate includes a solar cell substrate, the solar cell substrate includes a substrate, and a first electrode layer, a photoactive layer, and a second electrode layer sequentially stacked on one side of the substrate, the laser scribe line method is used to etch the first groove, the first groove penetrates the second electrode layer and the photoactive layer, and exposes the first electrode layer.

[0009] In conjunction with the second aspect, in some possible implementations, using a laser beam to scribing along at least three paths on the surface of a pre-placed substrate to form at least three scribing grooves includes: for each path, using a laser beam to scribing along the path multiple times sequentially to form a scribing groove; preferably, the power of the laser beam is 0.5-0.6 watts; preferably, the number of scribing operations for each path is 2; preferably, the laser beam includes a green laser beam; preferably, the frequency of the laser beam is 1500-2000 kHz, and the speed is 500-800 mm / s; preferably, the distance between adjacent paths is 2-4 μm.

[0010] In conjunction with the second aspect, in some possible implementations, at least three paths include at least two edge paths and at least one non-edge path, with the non-edge path located between the at least two edge paths; forming at least three scribe grooves by using a laser beam to scribing along at least three paths on the surface of the pre-set substrate includes: scribing along the edge path with a first laser beam to form an edge scribe groove; and scribing along the non-edge path with a second laser beam to form a non-edge scribe groove, wherein the power of the first laser beam and the power of the second laser beam are different.

[0011] In conjunction with the second aspect, in some possible implementations, the power of the first laser beam is less than the power of the second laser beam; preferably, the power of the first laser beam is 0.5-0.6 watts and the power of the second laser beam is 0.7-0.8 watts; preferably, the first laser beam and the second laser beam each include a green laser beam; preferably, the frequencies of the first laser beam and the second laser beam are 350~100kHz and the speeds are 500~800mm / s, respectively; preferably, the distance between adjacent paths is 2~4µm.

[0012] In conjunction with the second aspect, in some possible implementations, the power of the first laser beam is greater than the power of the second laser beam; preferably, the power of the first laser beam is 0.6-0.7 watts and the power of the second laser beam is 0.45-0.5 watts; preferably, the first laser beam and the second laser beam each include a green laser beam; preferably, the frequencies of the first laser beam and the second laser beam are 120~1000 kHz and the speeds are 500~800 mm / s, respectively; preferably, the distance between adjacent paths is 2~4 μm.

[0013] According to the battery module and laser grooving method provided in the embodiments of this application, by setting a stepped structure on the inner wall of the first groove, a "habitat" is provided for the debris of the falling second electrode layer, which physically blocks the possibility of these debris forming a short circuit between the first electrode layer and the second electrode layer, significantly improving the production yield and long-term reliability of the battery module. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the cross-sectional structure of the battery module provided in the first embodiment of this application.

[0015] Figure 2 This is a schematic diagram of the cross-sectional structure of the battery module provided in the second embodiment of this application.

[0016] Figure 3 This is a schematic diagram of the cross-sectional structure of the battery module provided in the third embodiment of this application.

[0017] Figure 4 This is a schematic diagram of the cross-sectional structure of the battery module provided in the fourth embodiment of this application.

[0018] Figure 5 This is a schematic flowchart of the laser grooving method provided in the fifth embodiment of this application.

[0019] Figure 6 Execution provided for the first embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process.

[0020] Figure 7a Execution provided for the second embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process.

[0021] Figure 7b Execution provided for the third embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process.

[0022] Figure 8a Execution provided for the fourth embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process.

[0023] Figure 8b Execution provided for the fifth embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process.

[0024] Figure 9a This is a schematic flowchart of the laser grooving method provided in the sixth embodiment of this application.

[0025] Figure 9b To execute Figure 9a The diagram shows the laser scanning sequence during the laser grooving process.

[0026] Figure 10a This is a schematic flowchart of the laser grooving method provided in the seventh embodiment of this application.

[0027] Figure 10b To execute Figure 10a The diagram shows the laser scanning sequence during the laser grooving process.

[0028] Figure 11 Execution provided for the eighth embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process. Attached image description: Substrate 10, first electrode layer 21, photoactive layer 22, second electrode layer 23, first groove P3, first sub-groove P310, second sub-groove P320, third sub-groove P330, first connecting part C1, mesa S1, second connecting part C2, molten metal debris Q, cover plate 30, second groove P2, first transmission layer 24, second transmission layer 25, third groove P1, depth H, thickness T, distance D1, distance D2, width W, protrusion 230, height D3, scribing groove P, path L, first direction X, second direction Y, first scribing groove P31, second scribing groove P32, third scribing groove P33, fourth scribing groove P34, edge path L1, non-edge path L2. Detailed Implementation

[0030] Perovskite solar cells have become a research hotspot in next-generation photovoltaic technology due to their high photoelectric conversion efficiency and low-cost solution preparation process. To obtain higher output voltages, large-area perovskite solar cells are typically divided into multiple sub-cells using laser scribing technology and integrated in series on the same substrate. The grooves that penetrate from the top electrode (second electrode layer) and photoactive layer to expose the bottom electrode (first electrode layer) are commonly referred to as P3 grooves, and their function is to achieve series connection between adjacent sub-cells.

[0031] However, the inventors discovered two significant problems with the existing P3 laser etching process during actual production and reliability testing: First, molten metal debris generated during laser etching of the top electrode (usually metal) easily falls off and remains within the P3 groove. This conductive debris may overlap between the bottom electrode and the incompletely removed top electrode, forming a conductive path that can cause short circuits between sub-cells, leading to module failure. Second, due to the characteristics of laser-material interaction, raised "crater"-like burrs easily form at the edges of the P3 groove, especially at the top electrode layer. These "craters" can be hundreds of nanometers high and may puncture the upper encapsulation film or functional layer during subsequent lamination and encapsulation, causing module performance degradation or long-term reliability risks.

[0032] In view of this, embodiments of this application provide a battery module and a laser etching method. By improving the structural design of the P3 groove and / or the laser etching process, it is possible to effectively accept or avoid top electrode debris and eliminate or reduce the height of the "crater". This ensures high series efficiency while improving the yield and long-term reliability of the battery module.

[0033] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] In the accompanying drawings, the dimensions of layers and regions may be exaggerated for clarity. It is understood that when a structure is referred to as being "on" or "below" another structure, the structure may be directly on or below the other structure, or there may be intermediate structures. The same reference numerals always indicate the same structure. Structures referred to herein include any of the following: membrane, element, device, component, assembly.

[0035] When a structure is referred to as being “connected” to another structure, it can be directly connected to the other structure or indirectly connected to the other structure by means of one or more intermediate structures placed between them.

[0036] Figure 1 This is a schematic cross-sectional view of the battery module provided in the first embodiment of this application. Figure 1 As shown, the battery module provided in this embodiment includes: a substrate 10, a first electrode layer 21, a photoactive layer 22, and a second electrode layer 23. The first electrode layer 21 is located on one side of the substrate 10, the photoactive layer 22 is located on the side of the first electrode layer 21 away from the substrate 10, and the second electrode layer 23 is located on the side of the photoactive layer 22 away from the substrate 10. The battery module has a first groove P3, which penetrates the second electrode layer 23 and the photoactive layer 22, and exposes the first electrode layer 21. The first groove P3 includes a first sub-groove P310 and a second sub-groove P320 disposed adjacent to each other along the direction close to the substrate 10. The orthographic projection of the second sub-groove P320 on the substrate 10 is within the orthographic projection range of the first sub-groove P310 on the substrate 10.

[0037] The substrate 10 can be a rigid substrate (such as glass) or a flexible substrate (such as polyethylene terephthalate PET). The first electrode layer 21 is located on one side of the substrate 10, and its material can be a transparent conductive oxide (ITO, FTO). The photoactive layer 22 is located on the side of the first electrode layer 21 away from the substrate 10, and its material includes perovskite materials. The second electrode layer 23 is located on the side of the photoactive layer 22 away from the substrate 10, and its material is typically a metal (such as gold, silver, or aluminum) or a carbon material.

[0038] The first groove P3 includes a first sub-groove P310 and a second sub-groove P320 disposed adjacent to each other along the direction close to the substrate 10. The orthographic projection of the second sub-groove P320 is located within the orthographic projection range of the first sub-groove P310. In this case, the inner walls of the first sub-groove P310 and the second sub-groove P320, as well as the interface between the first sub-groove P310 and the second sub-groove P320, enclose a stepped structure. In other words, the inner wall of the first groove P3 includes a stepped structure, which includes a first connecting portion C1, a platform S1, and a second connecting portion C2 connected sequentially along the direction close to the substrate 10. The first connecting portion C1 encloses the sidewall of the first sub-groove P310, the second connecting portion C2 encloses the sidewall of the second sub-groove P320, and the platform S1 is parallel to the substrate 10. In this scenario, the molten metal debris Q generated during laser etching of the second electrode layer 23 to fabricate the first groove P3, when falling under gravity, is caught by the platform S1 and isolated on the "step" formed by the first sub-groove P310 and the second sub-groove P320. This prevents the debris from falling further to the bottom of the first groove P3 and contacting the exposed first electrode layer 21. This avoids the formation of tiny conductive bridges between the second electrode layer 23 and the first electrode layer 21, which could lead to short circuits between adjacent sub-cells, thus improving the reliability of the display module.

[0039] It should be noted that the stepped structure on the sidewall of the first groove P3 can be single-level (as in this embodiment) or multi-level. Multi-level steps can more effectively accommodate debris of different sizes, providing more reliable protection.

[0040] In one embodiment, such as Figure 1 As shown, the battery module also includes a cover plate 30, which is located on the side of the second electrode layer 23 away from the substrate 10. The cover plate 30 seals the opening of the first groove P3. The cover plate 30 can be glass or a polymer encapsulating film to protect the internal structure of the battery module from water and oxygen corrosion. In this case, a cavity is formed in the first groove P3.

[0041] In one embodiment, such as Figure 1 As shown, the battery module also has a second groove P2. The second groove P2 penetrates the photoactive layer 22 and exposes the first electrode layer 21. The second electrode layer 23 fills the second groove P2 and contacts the first electrode layer 21. This is a key structure for realizing the series connection of sub-cells. The second electrode layer 23 connects the first electrode layer 21 of the adjacent sub-cell within the second groove P2, realizing the series connection between the adjacent sub-cells.

[0042] In one embodiment, such as Figure 1As shown, the battery module also includes a first transport layer 24 and a second transport layer 25. The first transport layer 24 is located between the first electrode layer 21 and the photoactive layer 22, and is, for example, a hole transport layer (such as Spiro-OMeTAD, NiO). x The second transport layer 25 is located between the photoactive layer 22 and the second electrode layer 23, and is preferably an electron transport layer (such as SnO2, PCBM). The first groove P3 and the second groove P2 penetrate the first transport layer 24 and the second transport layer 25, respectively.

[0043] In one embodiment, such as Figure 1 As shown, the battery module also has a third groove P1. The third groove P1 penetrates the first electrode layer 21, and the orthographic projection of the third groove P1 on the substrate 10 is located on the side of the orthographic projection of the second groove P2 on the substrate 10 away from the first groove P3. The first transport layer 24 fills the third groove P1. The third groove P1 is used to pattern and divide the first electrode layer 21 to define independent sub-cells.

[0044] According to the battery module provided in this embodiment, by setting a stepped structure on the inner wall of the first groove P3, a "habitat" is provided for the debris of the falling second electrode layer 23, which physically blocks the possibility of these debris forming a short circuit between the first electrode layer 21 and the second electrode layer 23, significantly improving the production yield and long-term reliability of the battery module.

[0045] Figure 2 This is a schematic cross-sectional view of the battery module provided in the second embodiment of this application. Figure 2 As shown, in this embodiment, the depth H of the first sub-groove P310 is greater than or equal to the thickness T of the second electrode layer 23. This has two advantages: First, it further improves reliability. Specifically, if the depth of the first sub-groove P310 is too shallow, the height of the molten metal debris Q falling onto the platform S1 may be greater than the depth of the first sub-groove P310. In other words, the molten metal debris Q will still protrude from the surface of the second electrode layer 23 away from the substrate 10, thus piercing the upper film layer. Second, it facilitates process implementation. Specifically, the precision of conventional grooving equipment limits the depth of the first sub-groove P310; a shallow first sub-groove P310 is difficult to achieve.

[0046] For example, the depth H of the first sub-groove P310 is equal to the thickness T of the second electrode layer 23. In other words, the bottom of the first sub-groove P310 is flush with the surface of the second electrode layer 23 near the substrate 10, that is, the first sub-groove P310 just penetrates the second electrode layer 23.

[0047] For example, the depth H of the first sub-groove P310 is greater than the thickness T of the second electrode layer 23. In other words, the bottom of the first sub-groove P310 is closer to the substrate 10 than the second electrode layer 23, that is, while the first sub-groove P310 penetrates the second electrode layer 23, it further penetrates a portion of the film layer between the second electrode layer 23 and the substrate 10.

[0048] In one embodiment, the first groove P3 further includes a third sub-groove P330. The third sub-groove P330 is adjacent to the second sub-groove P320 and is located on the side of the second sub-groove P320 closer to the substrate 10. The orthographic projection of the third sub-groove P330 on the substrate 10 is within the orthographic projection range of the second sub-groove P320 on the substrate 10. Thus, the inner wall of the first groove P3 forms a two-stage stepped structure, capable of accommodating more or larger debris.

[0049] For example, the distance D1 between the interface of the second sub-groove P320 and the third sub-groove P330 and the substrate 10 is less than or equal to the distance D2 between the photoactive layer 22 and the substrate 10. This makes the width of the first groove P3 more uniformly distributed along the third direction Z, ensuring the reliability of the first groove P3 and the controllability of etching.

[0050] According to the battery module provided in this embodiment, by precisely defining the depth and positional relationship of each sub-groove, the stepped structure can effectively receive debris without introducing new process complexity or structural defects, thus ensuring the feasibility and robustness of the improved solution.

[0051] In one embodiment, see Figure 2 As shown, the width W of the first groove P3 is greater than or equal to 30 micrometers and less than or equal to 50 micrometers. For example, W = 40 micrometers. The width of the first groove P3 mentioned here refers to its maximum width. For example, as... Figure 2 As shown, when the first groove P3 has a stepped structure, the width of the first groove P3 is measured using the width of the first sub-groove P310. The width range provided in this embodiment can minimize the dead area and improve the photoelectric conversion efficiency of the battery module while ensuring effective insulation and series connection.

[0052] Figure 3 This is a schematic cross-sectional view of the battery module provided in the third embodiment of this application. Figure 3 The battery module shown and Figure 1 , Figure 2 The difference in the battery module shown is that, in this embodiment, the second electrode layer 23 includes a protrusion 230 located at the opening of the first groove P3, and the height D3 of the protrusion 230 is less than 200 nanometers. For example, the height D3 of the protrusion 230 is 180 nanometers.

[0053] In this case, the crater at the opening of the first groove P3 is not completely flattened by the cover plate, but its height is insufficient to puncture the cover plate 30, thus meeting the reliability requirements.

[0054] Figure 4 This is a schematic cross-sectional view of the battery module provided in the fourth embodiment of this application. Figure 4 As shown, the battery module provided in this embodiment includes a substrate 10, a first electrode layer 21, a photoactive layer 22, and a second electrode layer 23. The first electrode layer 21 is located on one side of the substrate 10, the photoactive layer 22 is located on the side of the first electrode layer 21 away from the substrate 10, and the second electrode layer 23 is located on the side of the photoactive layer 22 away from the substrate 10. The battery module has a first groove P3 that penetrates the second electrode layer 23 and the photoactive layer 22, exposing the first electrode layer 21. The second electrode layer 23 includes a protrusion 230 located at the opening of the first groove P3, and the height D3 of the protrusion 230 is less than 200 nanometers.

[0055] The protrusion 230 is a "crater" that is difficult to completely avoid after the laser etching forms the first groove P3. According to the laser grooving method provided in the following method embodiment, the height H of the protrusion 230 can be strictly controlled within a low-risk range of less than 200 nanometers. Compared with the traditional process, which may produce a "crater" of 500 nanometers or even higher, this embodiment reduces the height by more than 60%.

[0056] It should be noted that if the "crater" height is too high, the top cover plate 30 may be punctured by the sharp protrusion 230 under pressure and temperature during lamination, leading to component seal failure, water and oxygen intrusion, accelerated decomposition of the perovskite material, and permanent performance degradation. Simultaneously, the protrusion 230 may fall into the first groove P3 during lamination, causing a short circuit. By strictly controlling the height D3 of the protrusion 230 to less than 200 nanometers, the risk of puncturing the cover plate 30 can be reduced. Furthermore, even if the protrusion 230 falls into the first groove P3, its small size will prevent a short circuit between the first electrode layer 21 and the second electrode layer 23.

[0057] It should be noted that, in this embodiment, the first groove P3 can be a groove with a uniform width, or it can be... Figure 3 The groove shown has an uneven width.

[0058] This application provides a laser grooving method suitable for preparing the first groove P3 in a battery module. Figure 5 This is a schematic flowchart of the laser grooving method provided in the fifth embodiment of this application. Figure 6 Execution provided for the first embodiment of this application Figure 5 The diagram illustrates the laser scanning sequence during the laser grooving process. Figure 5 As shown, the laser grooving method 500 includes: Step S510, see Figure 6 The laser beam is used to scribing along at least three paths L on the surface of the pre-placed substrate 100 to form at least three scribing grooves P.

[0059] In this configuration, at least three scribe lines P are arranged sequentially and connected in a direction parallel to the pre-set substrate 100, with at least two scribe lines P that are adjacent in fabrication order spaced apart. "Spaced apart" here means that two scribe lines P are not physically adjacent, and at least one scribe line P is provided between them. The at least three scribe lines P include at least one group, with each group consisting of two scribe lines P that are adjacent in fabrication order, spaced apart. The path mentioned here can be planned by computer software; no physical path is explicitly shown on the pre-set substrate 100. The width of the scribe line obtained by scribes along a path L can be the width formed by expanding outwards on both sides of the path L as a symmetrical axis; twice the outward expansion distance is the width of the scribe line P.

[0060] For example, the scribing groove P extends along a first direction X, and at least three scribing grooves P are arranged sequentially along a second direction Y, which is perpendicular to the first direction X. The at least three scribing grooves P are connected in the second direction Y, together forming a first groove P3.

[0061] According to the laser grooving method provided in this embodiment, by setting at least two grooves with adjacent preparation sequences, that is, the arrangement order of at least three grooves is different from the grooving order, it is possible to prevent the crater from being too high due to the unilateral accumulation of energy.

[0062] Figure 7a Execution provided for the second embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process. Figure 7b Execution provided for the third embodiment of this application Figure 5 The diagram illustrates the laser scanning sequence during the laser grooving process. (Combined with...) Figure 7a and Figure 7b As shown, taking three scribing grooves as an example, the three scribing grooves include: a first scribing groove P31, a second scribing groove P32, and a third scribing groove P33, which are prepared sequentially. In this case, along the second direction Y, the arrangement order of the first scribing groove P31, the second scribing groove P32, and the third scribing groove P33 includes two possibilities.

[0063] The first case, such as Figure 7a As shown, the first scribing groove P31, the third scribing groove P33, and the second scribing groove P32 are arranged sequentially, that is, along the second direction Y, the preparation order of the three scribing grooves is 1-3-2. In other words, the laser scanning order is from the two sides to the middle.

[0064] The second scenario, such as Figure 7b As shown, the second scribing groove P32, the first scribing groove P31, and the third scribing groove P33 are arranged sequentially, that is, along the second direction Y, the preparation order of the three scribing grooves is 2-1-3. In other words, the laser scanning order is from the middle to the sides.

[0065] Compared to the other two cases, the advantage of the first case (1) is that the first and second scribings define the two relative boundaries of the first groove P3 respectively, and the third scribing is performed between the first scribing groove P31 and the second scribing groove P32. In this case, the accuracy requirement for the position of the third scribing is not so high, and it is easy to implement the process.

[0066] Figure 8a Execution provided for the fourth embodiment of this application Figure 5 The diagram shows the laser scanning sequence during the laser grooving process. Figure 8b Execution provided for the fifth embodiment of this application Figure 5 The diagram illustrates the laser scanning sequence during the laser grooving process. (Combined with...) Figure 8a and Figure 8b As shown, taking four scribing grooves as an example, these four scribing grooves include: a first scribing groove P31, a second scribing groove P32, a third scribing groove P33, and a fourth scribing groove P34, which are prepared sequentially. In this case, the arrangement order of the first scribing groove P31, the second scribing groove P32, the third scribing groove P33, and the fourth scribing groove P34 along the second direction Y includes two possibilities.

[0067] The first case, such as Figure 8a As shown, the first scribing groove P31, the second scribing groove P32, the fourth scribing groove P34, and the third scribing groove P33 are arranged sequentially, that is, along the second direction Y, the fabrication order of the three scribing grooves is 1-2-4-3. In this case, it is equivalent to adding a fourth path on the basis of the core three-path etching, which is equivalent to adding a more refined trimming step on the basis of the core "three-line method". After completing the main etching, the area between the second scribing groove P32 and the third scribing groove P33 is focused on trimming, which can further smooth the groove wall morphology on this side.

[0068] The second scenario, such as Figure 8b As shown, the first etched groove P31, the third etched groove P33, the fourth etched groove P34, and the second etched groove P32 are arranged sequentially, that is, along the second direction Y, the fabrication order of the three etched grooves is 1-3-4-2. In this case, the two sets of etched grooves with adjacent etching sequences are spaced apart, including the first etched groove P31 and the second etched groove P32, the second etched groove P32, and the third etched groove P33. The advantage is that it helps to further reduce the height of the crater.

[0069] It should be noted that the number of scribed grooves P is not limited to three or four, and can be increased to five or more as needed to achieve a wider first groove P3 or to pursue a smoother effect.

[0070] according to Figure 5 The laser grooving method shown can reduce the crater height by adjusting the preparation order and arrangement sequence. Furthermore, the crater height can be further reduced by adjusting the laser parameter configuration.

[0071] Figure 9a This is a schematic flowchart of the laser grooving method provided in the sixth embodiment of this application. Figure 9b To execute Figure 9a The diagram illustrates the laser scanning sequence during the laser grooving process. (See attached image.) Figure 9a and Figure 9b In this embodiment, step S510 is specifically executed as follows: In step S910, for each path, a laser beam is used to repeatedly scribble along the path to form a scribing groove. In other words, for each path, a low-power laser is used to perform multiple repeated scans, which is a "grinding" type of processing strategy.

[0072] It should be noted that the focus of this embodiment is on the etching method for each path; for the etching sequence, please refer to [link to relevant documentation]. Figures 7a-8b The illustrated embodiment. For example, Figure 9a and Figure 9b The illustrated embodiment uses Figure 8a The engraving sequence shown is an example.

[0073] For example, the power of the laser beam is 0.5-0.6 watts. For instance, 0.5 watts.

[0074] For example, each path is marked twice.

[0075] For example, the laser beam includes a green laser beam.

[0076] For example, the laser beam has a frequency of 1500~2000kHz and a speed of 500~800mm / s. For instance, the laser beam has a frequency of 1700kHz and a speed of 650mm / s.

[0077] For example, the distance between adjacent paths is 2~4µm. For instance, the distance between adjacent paths is 3µm.

[0078] In one embodiment, the at least three paths include at least two edge paths L1 and at least one non-edge path L2, with the non-edge path L1 located between the at least two edge paths L2; ​​the etching order along the edge path L1 takes precedence over the etching order along the non-edge path L2.

[0079] The laser grooving method provided in this embodiment employs a low-power laser for repeated scanning, a "grinding" processing strategy. Through multiple thermal cycles, the material is slowly and uniformly removed and reflowed, resulting in grooves with very smooth edges, effectively suppressing the formation of large-sized "craters." Simultaneously, the low-energy scribing lines do not cause large-area edge chipping of the metal film, thus preventing the formation of craters.

[0080] Figure 10a This is a schematic flowchart of the laser grooving method provided in the seventh embodiment of this application. Figure 10b To execute Figure 10a The diagram illustrates the laser scanning sequence during the laser grooving process. (See attached image.) Figure 10a and Figure 10b In this embodiment, the at least three paths include at least two edge paths L1 and at least one non-edge path L2, with the non-edge path L2 located between the at least two edge paths L1. Edge paths L1 refer to the paths located on both sides of the entire path in the second direction Y. The number of edge paths L1 on both sides can be equal or unequal. Non-edge paths L2 refer to paths other than the edge paths.

[0081] Step S510 is specifically executed as follows: In step S1010, the first laser beam is used to scribing along the edge path L1 to form an edge scribing groove.

[0082] In step S1020, a second laser beam is used to scribing along the non-edge path L2 to form a non-edge scribing groove. The power of the first laser beam and the power of the second laser beam are not equal.

[0083] It should be noted that the execution order of the above two steps can be reasonably set according to actual needs. For example, Figure 10a and Figure 10b The illustrated embodiment uses Figure 8a The etching sequence shown is an example. The focus of this embodiment is on the etching method for each path, and the etching sequence can be reasonably set according to actual needs.

[0084] For example, the power of the first laser beam is less than the power of the second laser beam. For instance, the power of the first laser beam is 0.5-0.6 watts, and the power of the second laser beam is 0.7-0.8 watts. For example, the power of the first laser beam is 0.55 watts, and the power of the second laser beam is 0.75 watts.

[0085] For example, the first laser beam and the second laser beam each comprise a green laser beam.

[0086] For example, the frequencies of the first laser beam and the second laser beam are 350~100kHz and the speeds are 500~800mm / s, respectively. For instance, the frequencies of the first laser beam and the second laser beam are 500kHz and the speeds are 650mm / s, respectively.

[0087] For example, the distance between adjacent paths is 2~4µm. For instance, the distance between adjacent paths is 3µm.

[0088] According to the laser grooving method provided in this embodiment, a low-power laser is first used for pre-etching and preliminary shaping on both sides, and then a higher-power laser is used to remove the residual "ridge" in the middle in one go, and high energy is used to finally melt and flatten both sides. This solution achieves a good balance between efficiency and effect. At the same time, this solution forms a "stepped" structure by using multi-segment scribing (i.e., scribing through multiple paths to obtain multiple interconnected scribing grooves, rather than scribing through a single path to directly obtain a complete scribing groove), combined with different laser energies. In this way, crater debris at the opening of the first groove P3 will not fall directly into the first groove P3, avoiding short circuits.

[0089] Figure 11 Execution provided for the eighth embodiment of this application Figure 5 The diagram illustrates the laser scanning sequence during the laser grooving process. (See attached image.) Figure 11 In this embodiment, the power of the first laser beam is less than the power of the second laser beam. For example, the power of the first laser beam is 0.6-0.7 watts, and the power of the second laser beam is 0.45-0.5 watts. For instance, the power of the first laser beam is 0.65 watts, and the power of the second laser beam is 0.5 watts.

[0090] For example, the first laser beam and the second laser beam each comprise a green laser beam.

[0091] For example, the frequencies of the first laser beam and the second laser beam are 120~1000kHz and the speeds are 500~800mm / s, respectively. For instance, the frequencies of the first laser beam and the second laser beam are 500kHz and the speeds are 650mm / s, respectively.

[0092] For example, the distance between adjacent paths is 2~4µm. For instance, the distance between adjacent paths is 3µm.

[0093] According to the laser grooving method provided in this embodiment, a high-power laser is first used to quickly create grooves, and then a low-power laser is used to finely "clean" and "polish" the bottom and walls of the groove. This is particularly beneficial for removing debris and molten material generated in the previous process, forming a clean and regularly shaped groove. At the same time, high-power energy is used to scribing to cause the metal electrode to "turn outward," forming a "micron"-level crater. Then, low-energy scribing is used to melt and form the bottom of the "crater," or even eliminate the crater opening.

[0094] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0095] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A battery module, characterized in that, include: substrate; The first electrode layer is located on one side of the substrate; A photoactive layer is located on the side of the first electrode layer away from the substrate; as well as The second electrode layer is located on the side of the photoactive layer away from the substrate; The battery module has a first groove that penetrates the second electrode layer and the photoactive layer and exposes the first electrode layer. The first groove includes a first sub-groove and a second sub-groove that are adjacent to each other along the direction close to the substrate. The orthographic projection of the second sub-groove on the substrate is located within the orthographic projection range of the first sub-groove on the substrate.

2. The battery module according to claim 1, characterized in that, The depth of the first sub-groove is greater than or equal to the thickness of the second electrode layer; Preferably, the first groove further includes a third sub-groove, which is adjacent to the second sub-groove and located on the side of the second sub-groove closer to the substrate. The orthographic projection of the third sub-groove on the substrate is within the orthographic projection range of the second sub-groove on the substrate. Preferably, the distance between the interface between the second sub-groove and the third sub-groove and the substrate is greater than or equal to the distance between the photoactive layer and the substrate.

3. The battery module according to claim 1, characterized in that, The width of the first groove is greater than or equal to 30 micrometers and less than or equal to 50 micrometers; Preferably, the second electrode layer includes a protrusion located at the opening of the first groove, and the height of the protrusion is less than 200 nanometers; Preferably, the battery module further includes a cover plate located on the side of the second electrode layer away from the substrate, and the cover plate seals the opening of the first groove; Preferably, the battery module further has a second groove that penetrates the photoactive layer and exposes the first electrode layer, and the second electrode layer fills the second groove and contacts the first electrode layer; Preferably, the battery module further includes a first transport layer, the first transport layer being located between the first electrode layer and the photoactive layer, the first groove and the second groove respectively penetrating the first transport layer; and / or, the battery module further includes a second transport layer, the second transport layer being located between the photoactive layer and the second electrode layer, the first groove and the second groove respectively penetrating the second transport layer; Preferably, the first transport layer includes a hole transport layer, and the second transport layer includes an electron transport layer; Preferably, the battery module further has a third groove that penetrates the first electrode layer, and the orthographic projection of the third groove on the substrate is located on the side of the orthographic projection of the second groove on the substrate that is away from the orthographic projection of the first groove on the substrate, and the first transport layer fills the third groove; Preferably, the material of the photoactive layer includes perovskite.

4. A laser grooving method, characterized in that, include: At least three scribe grooves are formed by scribing along at least three paths on the surface of a pre-set substrate using a laser beam. In this configuration, at least three scribing grooves are arranged sequentially and connected in a direction parallel to the pre-formed substrate, and at least two scribing grooves with adjacent preparation sequences are spaced apart.

5. The laser grooving method according to claim 4, characterized in that, The step of using a laser beam to scribing along at least three paths on the surface of a pre-placed substrate to form at least three scribing grooves includes: For each of the aforementioned paths, the laser beam is used to sequentially scribble multiple times along the path to form the scribing groove; Preferably, the power of the laser beam is 0.5-0.6 watts; Preferably, the number of scratches on each path is 2; Preferably, the laser beam comprises a green laser beam; Preferably, the frequency of the laser beam is 1500~2000KHZ and the speed is 500~800mm / s; Preferably, the distance between adjacent paths is 2~4 μm.

6. The laser grooving method according to claim 4, characterized in that, The at least three paths include at least two edge paths and at least one non-edge path, wherein the non-edge path is located between the at least two edge paths; the step of using a laser beam to scribing along the at least three paths on the surface of the pre-placed substrate to form at least three scribing grooves includes: A first laser beam is used to scribing along the edge path to form an edge scribing groove; A second laser beam is used to scribing along the non-edge path to form a non-edge scribing groove, wherein the power of the first laser beam and the power of the second laser beam are different.

7. The laser grooving method according to claim 6, characterized in that, The power of the first laser beam is less than the power of the second laser beam; Preferably, the power of the first laser beam is 0.5-0.6 watts, and the power of the second laser beam is 0.7-0.8 watts; Preferably, the first laser beam and the second laser beam each comprise a green laser beam; Preferably, the frequencies of the first laser beam and the second laser beam are 350~100kHz and the speeds are 500~800mm / s, respectively. Preferably, the distance between adjacent paths is 2~4 μm.

8. The laser grooving method according to claim 6, characterized in that, The power of the first laser beam is greater than the power of the second laser beam; Preferably, the power of the first laser beam is 0.6-0.7 watts, and the power of the second laser beam is 0.45-0.5 watts; Preferably, the first laser beam and the second laser beam each comprise a green laser beam; Preferably, the frequencies of the first laser beam and the second laser beam are 120~1000kHz and the speeds are 500~800mm / s, respectively; Preferably, the distance between adjacent paths is 2~4 μm.

9. The laser grooving method according to any one of claims 4-8, characterized in that, The at least three paths include at least two edge paths and at least one non-edge path, the non-edge path being located between the at least two edge paths; the etching order along the edge paths takes precedence over the etching order along the non-edge paths.

10. The laser grooving method according to any one of claims 4-8, characterized in that, The at least three scribing grooves include a first scribing groove, a second scribing groove, a third scribing groove, and a fourth scribing groove prepared sequentially, wherein the first scribing groove, the second scribing groove, the fourth scribing groove, and the third scribing groove are arranged in sequence; or, the first scribing groove, the third scribing groove, the fourth scribing groove, and the second scribing groove are arranged in sequence. Preferably, the pre-placed substrate includes a solar cell substrate, which includes a substrate and a first electrode layer, a photoactive layer, and a second electrode layer stacked sequentially on one side of the substrate. The laser grooving method is used to etch a first groove, which penetrates the second electrode layer and the photoactive layer and exposes the first electrode layer.

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