Sliced ​​battery and forming method thereof, photovoltaic module

Abstract

The embodiments of the present application relate to the field of photovoltaic technology, and in particular to a sliced ​​cell and a method for forming the same, and a photovoltaic module. The sliced ​​cell comprises: the sliced ​​cell is formed by slicing a whole cell, and the sliced ​​cell has a cutting surface formed by the slicing process; wherein at least part of the cutting surface has a first texture structure, and the first texture structure includes at least a plurality of rectangular portions, and at least one of the rectangular portions partially overlaps with at least one adjacent rectangular portion. The embodiments of the present application are at least conducive to improving the performance of the sliced ​​cell and the photovoltaic module.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of photovoltaic technology, and in particular to a sliced ​​battery and a method for forming the same, and a photovoltaic module. Background Art

[0002] With the continuous development and application of photovoltaic power generation technology, the manufacturing method and structure of photovoltaic cells have also received widespread attention. With the continuous increase in the output current of photovoltaic modules formed after photovoltaic cell packaging, the impact of the internal loss of photovoltaic modules is becoming increasingly greater. In order to reduce the internal loss of photovoltaic modules and increase the output power of photovoltaic modules, the whole photovoltaic cell is usually cut into slices and then packaged to reduce the current of the photovoltaic cells in series, thereby reducing the internal loss of the photovoltaic module.

[0003] However, the current process of cutting photovoltaic cells will cause damage to the sliced ​​cells and reduce the performance of the sliced ​​cells. Summary of the invention

[0004] The embodiments of the present application provide a sliced ​​cell and a method for forming the same, and a photovoltaic module, which are at least beneficial to improving the performance of the sliced ​​cell and the photovoltaic module.

[0005] An embodiment of the present application provides a sliced ​​battery, including: the sliced ​​battery is formed by slicing a whole battery, and the sliced ​​battery has a cutting surface formed by the slicing process; wherein at least part of the cutting surface has a first texture structure, the first texture structure includes at least a plurality of rectangular portions, and at least one rectangular portion partially overlaps with at least one adjacent rectangular portion.

[0006] In some embodiments, the rectangular portion is recessed toward the inside of the split battery.

[0007] In some embodiments, the depth of the rectangular portion recessed toward the split battery is 10 nm to 500 nm.

[0008] In some embodiments, the bottom surface of the rectangular portion is flat.

[0009] In some embodiments, the angle between the bottom surface and the cutting surface is less than 30°.

[0010] In some embodiments, along a direction perpendicular to the cutting surface, there is a height difference between bottom surfaces of two overlapping rectangular portions.

[0011] In some embodiments, along a direction perpendicular to the cutting surface, a height difference between bottom surfaces of two overlapping rectangular portions is 10 nm to 500 nm.

[0012] In some embodiments, any rectangular portion is adjacent to at least one rectangular portion, and any rectangular portion partially overlaps with at least one adjacent rectangular portion.

[0013] In some embodiments, the rectangular portion includes a long side and a wide side, the size of the long side is a first size, the size of the wide side is a second size, the product of the first size and the second size is a first value, and for any rectangular portion, the ratio of the area value of the bottom surface of the rectangular portion to the first value is 10% to 90%.

[0014] In some embodiments, the density of the rectangular portions located on the cutting surface is 10 3 ~10 5 / mm 2 .

[0015] In some embodiments, the rectangular portion includes a long side and a wide side, and along the extension direction of the long side, the size of the long side is 3 μm to 15 μm, and / or along the extension direction of the wide side, the size of the wide side is 3 μm to 15 μm.

[0016] Accordingly, an embodiment of the present application also provides a method for forming a sliced ​​battery, comprising: providing a whole battery; slicing the whole battery to form a sliced ​​battery, the sliced ​​battery having a cutting surface formed by the slicing process; wherein at least part of the cutting surface has a first texture structure, the first texture structure includes at least a plurality of rectangular portions, and at least one rectangular portion partially overlaps with at least another adjacent rectangular portion.

[0017] In some embodiments, the slicing process includes: using a laser grooving process to laser groove the entire battery to form grooves on a portion of the surface of the entire battery, the laser wavelength of the laser grooving process is 500nm~1000nm, the laser pulse width is 10ns~1000ns, and the laser power is 50W~100W.

[0018] In some embodiments, the slicing process further includes: heating the grooves using a laser heating process, the laser wavelength of the laser heating process is 500nm~1000nm, the laser pulse width is 10ns~1000ns, and the laser power is 20W~50W.

[0019] Correspondingly, an embodiment of the present application also provides a photovoltaic module, including: a battery string, the battery string includes the sliced ​​battery of any one of the above embodiments; a packaging film, the packaging film is used to cover the surface of the battery string; and a cover plate, the cover plate is used to cover the surface of the packaging film away from the battery string.

[0020] The technical solution provided by the embodiments of the present application has at least the following advantages:

[0021] In the technical solution provided in the embodiment of the present application, a segmented solar cell has a cutting surface formed by a slicing process, and the cutting surface has a first texture structure. The first texture structure includes a plurality of rectangular portions. The rectangular portions enable the segmented solar cell to have a lower specific surface area, which can effectively reduce the density of dangling bonds on the cutting surface, thereby facilitating the reduction of the recombination current at the edge of the segmented solar cell, thereby improving the performance of the segmented solar cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] One or more embodiments are exemplarily described by pictures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0023] Figure 1 A schematic diagram of the structure of a sliced ​​battery provided for related technology;

[0024] Figure 2 A scanning electron microscope image of a partial cut surface of a split battery provided in an embodiment of the present application;

[0025] Figure 3 A cross-sectional view of a split battery provided in an embodiment of the present application;

[0026] Figure 4 for Figure 2 A top view of the portion of the cut surface within the dashed box;

[0027] Figure 5 A schematic cross-sectional view of a partial structure of a split battery provided in an embodiment of the present application;

[0028] Figure 6 A schematic cross-sectional view of a partial structure of another type of split battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0029] As known from the background technology, cutting will reduce the performance of the sliced ​​battery.

[0030] After analysis, it is found that many module technologies have emerged to improve the energy density of photovoltaic modules. Half-cell module technology, stack welding technology and shingle technology are representative technologies. The characteristics of these technologies are to cut the whole photovoltaic cell into half-segmented cells, one-third-segmented cells or smaller-sized segmented cells, so as to fill as many segmented cells as possible in the module to increase the effective power generation area. At the same time, the current of the segmented cells is reduced, thereby reducing power loss, which is conducive to comprehensively improving the module power.

[0031] Figure 1A schematic structural diagram of a sliced ​​battery provided for related technology.

[0032] However, cutting a whole photovoltaic cell will cause a certain efficiency loss, mainly including the following two types. One is mechanical loss. For example, after the laser damaged area melts, the silicon atoms lose their orderly arrangement in the area where the silicon recrystallizes. The other is that a large number of dangling bonds will form on the surface of the broken part, becoming electron-hole recombination centers. Take the cut TOPCon cell (Tunnel Oxide Passivated Contact) as an example. Figure 1 The area exposed by the cut surface 10 includes the emitter 12 and the silicon wafer substrate 11. From the perspective of carrier recombination, cutting increases the recombination of the pn junction region and the base region.

[0033] To solve the above problems, an embodiment of the present application provides a slice battery, wherein the cut surface of the slice battery has a first texture structure, and the first texture structure includes a plurality of rectangular portions. The rectangular portions enable the cut surface of the slice battery to have a smaller surface area, and enable the slice battery to have a lower specific surface area, which can effectively reduce the density of dangling bonds on the cut surface, and is beneficial to reducing the recombination current at the edge of the slice battery, thereby improving the performance of the slice battery.

[0034] The following will be described in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present application, many technical details are provided in order to enable the reader to better understand the embodiments of the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the embodiments of the present application can be implemented.

[0035] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0036] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0037] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0038] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0039] In the description of the embodiments of the present application, the orientation or position relationship indicated by the technical terms "thickness", "upper" and "lower" is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0040] In the accompanying drawings corresponding to the embodiments of the present application, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, film, region or substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0041] In the description of the embodiments of the present application, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, film, region, or plate is referred to as "on / located on" another component, it can be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, film, region, or plate is "directly located on" another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it means that no other components are located in between.

[0042] The terms used in the description of the various embodiments described herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of the various embodiments described and in the appended claims, "component" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0043] The embodiment of the present application provides a sliced ​​battery, which is formed by slicing a whole battery.

[0044] In some embodiments, the sliced ​​cell can be any one of a PERC cell (Passivated Emitter and Rear Cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell), a TOPCon cell (Tunnel Oxide Passivated Contact), a HIT / HJT cell (Heterojunction Technology) or a BC cell (Back Contact).

[0045] In some embodiments, the sliced ​​cells can be monocrystalline silicon photovoltaic cells, polycrystalline silicon photovoltaic cells, amorphous silicon photovoltaic cells or multi-compound photovoltaic cells. The multi-compound photovoltaic cells can specifically be cadmium sulfide photovoltaic cells, gallium arsenide photovoltaic cells, copper indium selenide photovoltaic cells or perovskite photovoltaic cells.

[0046] In some embodiments, the sliced ​​cell may include a first passivation layer, a substrate, and a second passivation layer stacked in sequence, the substrate having a first surface and a second surface opposite to each other, the first passivation layer may be located on the first surface of the substrate, the second passivation layer may be located on the second surface of the substrate, the sliced ​​cell further includes a first electrode and a second electrode, the first electrode may penetrate the first passivation layer along the thickness direction of the first passivation layer and contact the first surface of the substrate, the second electrode may penetrate the second passivation layer along the thickness direction of the second passivation layer and contact the second surface of the substrate. The substrate is used to receive incident light and generate photogenerated carriers, the first electrode and the second electrode are used to collect photogenerated carriers, the first passivation layer and the second passivation layer may prevent the substrate surface from being oxidized or corroded, so as to improve the stability and life of the cell.

[0047] In some embodiments, the first electrode and the second electrode may also be both located on the first surface of the substrate or both located on the second surface of the substrate, that is, the split cell is a back contact cell.

[0048] In some embodiments, the material of the substrate may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon. In some embodiments, the material of the first passivation layer and the second passivation layer may include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide or aluminum oxide.

[0049] In some embodiments, the substrate may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any one of the V-group elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, which may be any one of the III-group elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0050] The substrate may have an emitter. In some embodiments, the emitter is located on a side of the substrate close to the first passivation layer and in contact with the first passivation layer. The doping element type of the emitter is opposite to the doping element type in the substrate, so that a PN junction is formed with the substrate. For example, if the doping element in the substrate is a P-type doping element, the doping element in the emitter is an N-type doping element; if the doping element in the substrate is an N-type doping element, the doping element in the emitter is a P-type doping element. The PN junction can receive incident light irradiated to the surface of the substrate and generate electron-hole pairs. For example, when the substrate is an N-type substrate, the separated electrons move into the substrate and the separated holes move into the emitter, so that a current can be formed.

[0051] In some embodiments, at least one side surface of the substrate may have a velvet structure, such as a pyramid-structured velvet. In this way, the velvet structure can enhance the substrate's absorption utilization rate of incident light, thereby facilitating the improvement of the photovoltaic conversion efficiency of the cell. If the photovoltaic cell is a single-sided cell, the velvet surface can be formed only on one side of the substrate, and the other side surface of the substrate can be a polished surface, that is, the polished surface of the substrate is flatter than the velvet surface. It should be noted that for single-sided cells, the velvet surface can be formed on the light-receiving surface of the substrate. If the photovoltaic cell is a double-sided cell, the velvet surface can be formed on both sides of the substrate.

[0052] In some embodiments, the material of the first passivation layer may include at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride. The first passivation layer may be a single-layer structure or a stacked-layer structure, for example, the single-layer structure may be a single-layer aluminum oxide film layer, a single-layer silicon oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the stacked-layer structure may be composed of at least two film layers stacked among an aluminum oxide film layer, a silicon oxide film layer, a silicon nitride film layer, or a silicon oxynitride film layer.

[0053] In some embodiments, the material of the second passivation layer may include at least one of aluminum oxide, silicon oxide, silicon nitride, or silicon oxynitride. The second passivation layer may be a single-layer structure or a stacked-layer structure, for example, the single-layer structure may be a single-layer aluminum oxide film layer, a single-layer silicon oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the stacked-layer structure may be composed of at least two film layers stacked among an aluminum oxide film layer, a silicon oxide film layer, a silicon nitride film layer, or a silicon oxynitride film layer.

[0054] In some embodiments, the second passivation layer may include a tunneling layer, a doped conductive layer and an anti-reflection layer stacked in sequence in a direction away from the substrate surface. The tunneling layer and the doped conductive layer are used to form a passivation contact structure. The tunneling layer can play a chemical passivation effect. Due to the presence of interface state defects on the substrate surface, the tunneling layer can saturate the dangling bonds on the substrate surface, reduce the defect state density on the substrate surface, and reduce the recombination centers on the substrate surface to reduce the carrier recombination rate, so that the interface state density on the substrate surface is larger. The increase in the interface state density will promote the recombination of photogenerated carriers, increase the fill factor, short-circuit current and open-circuit voltage of the photovoltaic cell, so as to improve the photoelectric conversion efficiency of the photovoltaic cell; the doped conductive layer can have a field passivation effect, and the doped conductive layer can form an electrostatic field, thereby causing minority carriers to escape from the interface, reducing the concentration of minority carriers, so that the carrier recombination rate at the substrate interface is lower, thereby increasing the open circuit voltage, short-circuit current and fill factor of the photovoltaic cell, and improving the photoelectric conversion efficiency of the photovoltaic cell. The anti-reflection layer can reduce the reflectivity of sunlight on the surface of photovoltaic cells, allowing more light to be absorbed and converted into electrical energy, thereby improving the light absorption efficiency of photovoltaic cells. The anti-reflection layer can also protect the internal structure of the cell, prevent the cell from being polluted by the environment, and improve the stability of the photovoltaic cell.

[0055] The material of the tunneling layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

[0056] The material of the doped conductive layer can be at least one of amorphous silicon, polycrystalline silicon or silicon carbide. The doped conductive layer has the same doping element as the substrate. If the doping element type of the substrate is P-type, the doping element type in the doped conductive layer is also P-type; if the doping element type of the substrate is N-type, the doping element type in the doped conductive layer is also N-type.

[0057] The material of the anti-reflection layer may be one of silicon oxide, aluminum oxide, silicon nitride or silicon oxynitride.

[0058] Figure 2 A scanning electron microscope image of a partial cut surface of a split battery provided in an embodiment of the present application; Figure 3 A cross-sectional view of a split battery provided in an embodiment of the present application; Figure 4 for Figure 2Top view of the partial cut surface within the dashed box.

[0059] refer to Figures 2 to 4 , the slice battery 100 has a cutting surface 110 formed by slicing; wherein at least part of the cutting surface 110 has a first texture structure, the first texture structure includes at least a plurality of rectangular portions 111, and at least one rectangular portion 111 partially overlaps with at least one adjacent rectangular portion 111. Compared with the case where there are more irregular convex structures or concave structures on the cutting surface 110, and the convex structures are more prominent and the concave structures are deeper, the embodiment of the present application uses the rectangular portion 111 as the structure on the cutting surface 110, which is conducive to reducing the specific surface area of ​​the slice battery 100, that is, it is conducive to reducing the flatness of the cutting surface 110 formed by the cutting of the slice battery 100, so that the surface area of ​​the cutting surface 110 formed by the cutting is smaller, which is conducive to reducing the dangling bonds and the recombination center on the surface of the cutting surface 110, and is conducive to reducing the recombination current at the edge of the slice battery 100, thereby improving the performance of the slice battery 100.

[0060] In some embodiments, the surface structure of the entire cutting surface 110 is the first texture structure.

[0061] It should be noted that, the larger the area occupied by the first texture structure on the cutting surface 110, the greater the number of rectangular portions 111 in the surface structure of the cutting surface 110, or in other words, the larger the area occupied by all the rectangular portions 111 on the cutting surface 110, the smaller the cutting damage of the cutting surface 110 formed by the slicing process, and the better the performance of the sliced ​​battery 100.

[0062] refer to Figure 3 The split battery 100 has a first surface 101 and a second surface 102 arranged along a first direction Y and arranged opposite to each other, and the two sides of the cutting surface 110 along the first direction Y are respectively connected to the first surface 101 and the second surface 102. It can be understood that the actual cutting surface 110 is not a completely flat plane. The direction perpendicular to the cutting surface 110 involved in the embodiment of the present application is: when the cutting surface 110 is approximated as a flat plane perpendicular to the first surface 101 (or perpendicular to the second surface 102), the direction perpendicular to the cutting surface 110 is taken, that is, the direction perpendicular to the cutting surface 110 is the second direction X involved in the relevant drawings.

[0063] It should be noted that if a rectangular portion 111 overlaps with another rectangular portion 111, the orthographic projection of the rectangular portion 111 on the cutting surface 110 along the second direction X is not a complete rectangle. In other words, if a rectangular portion 111 does not overlap with any rectangular portion 111, the orthographic projection of the rectangular portion 111 on the cutting surface 110 is a rectangle, a quadrilateral, or an approximate rectangle, where an approximate rectangle refers to a rectangle with small defects or small irregular shapes on the edges.

[0064] refer to Figure 2 and Figure 3 , the plurality of rectangular portions 111 in the first texture structure are arranged along a direction parallel to the cutting surface 110. The direction parallel to the cutting surface 110 involved in the embodiment of the present application is: when the cutting surface 110 is approximated as a flat plane perpendicular to the first surface 101 (or perpendicular to the second surface 102), the direction parallel to the cutting surface 110 is taken.

[0065] It should be noted that for the sliced ​​batteries formed by cutting the whole battery, it is difficult to control the surface structure on the cut surface. Therefore, it is too difficult to ensure that the cut surface is a smooth and flat surface. On this basis, it is relatively easy to set the surface structure of the cut surface to a rectangular portion. Therefore, the embodiment of the present application reduces cutting damage without increasing the difficulty of cutting, making the cut surface smoother.

[0066] Similarly, in practical applications, it is usually impossible to completely ensure that the surface structure of the cut surface is a rectangular portion. However, in some embodiments, ideally, the surface structure of the cut surface can be a first texture structure, and the first texture structure includes a plurality of continuously arranged rectangular portions, or the first texture structure includes a plurality of continuously arranged rectangular portions and a plane outside the rectangular portion. Both the rectangular portion and the plane are conducive to improving the flatness of the cut surface. This is in turn conducive to reducing the dangling bonds and recombination centers on the surface of the cut surface, and is conducive to reducing the recombination current at the edge of the slice battery, thereby improving the performance of the slice battery.

[0067] It should be noted that the embodiments of the present application do not limit the morphology of the surface structure on the cutting surface except for the rectangular portion.

[0068] In some embodiments, any rectangular portion 111 is adjacent to at least one rectangular portion 111, and any rectangular portion 111 partially overlaps with at least one adjacent rectangular portion 111. That is, for the multiple rectangular portions 111 in the first texture structure, each rectangular portion 111 overlaps with another rectangular portion 111, and the orthographic projection of each rectangular portion 111 in the first texture structure on the cutting surface 110 is an incomplete rectangle.

[0069] In some embodiments, any rectangular portion 111 is recessed toward the inside of the split battery 100. In other words, any rectangular portion 111 may be a recessed structure recessed toward the inside of the split battery 100.

[0070] In some embodiments, reference Figure 3 and Figure 4 , the bottom surface 123 of any rectangular portion 111 is a plane. A plane has a smaller surface area than a concave-convex surface. Therefore, the rectangular portion 111 as the surface structure of the cutting surface 110 is conducive to reducing the specific surface area of ​​the slice battery 100 obtained after the slicing process, thereby reducing the dangling bonds and recombination centers on the surface of the cutting surface 110, and reducing the recombination current at the edge of the slice battery 100, thereby improving the performance of the slice battery 100.

[0071] Figure 5 A schematic cross-sectional view of a partial structure of a split battery provided in an embodiment of the present application.

[0072] In some embodiments, reference Figure 5 , the angle α between any bottom surface 123 and the cutting surface 110 is less than 30°, that is, the angle α between the bottom surface 123 and the plane where the cutting surface 110 is located is less than 30°, for example, it can be 25°, 20°, 15°, 10°, 5° or 0°. The smaller the angle α between the bottom surface 123 and the plane where the cutting surface 110 is located, the smaller the surface area of ​​the rectangular portion 111, and the smaller the surface area of ​​the cutting surface 110, which is conducive to reducing the dangling bonds and recombination centers on the surface of the cutting surface 110, and is conducive to reducing the recombination current at the edge of the slice battery 100, thereby improving the performance of the slice battery 100.

[0073] Figure 6 A schematic cross-sectional view of a partial structure of another type of split battery provided in an embodiment of the present application.

[0074] In some embodiments, reference Figure 6, the depth H2 of any rectangular portion 111 recessed toward the slice battery 100 is 10nm~500nm. For example, it can be: 10nm, 60nm, 110nm, 120nm, 150nm, 170nm, 210nm or 300nm. In other embodiments, the depth H2 of the rectangular portion 111 recessed toward the slice battery 100 can be in the following ranges: 10nm~50nm, 50nm~100nm, 100nm~150nm, 150nm~200nm, 200nm~250nm, 250nm~300nm, 300nm~350nm, 350nm~400nm, 400nm~450nm or 450nm~500nm. If the depth of the rectangular portion 111 sunken into the slice battery 100 is too large, the specific surface area of ​​the slice battery 100 may be too large, that is, it may lead to more dangling bonds and recombination centers on the cut surface 110 formed by the cutting process. Therefore, the depth of the rectangular portion 111 sunken into the slice battery 100 is less than 500nm, which is conducive to ensuring that the cut surface 110 has fewer dangling bonds and recombination centers. The depth H2 of the rectangular portion 111 sunken into the slice battery 100 is greater than or equal to 10nm because it is too difficult to form a shallower rectangular portion by slicing. Therefore, within a controllable range, the depth of the rectangular portion can be made greater than 10nm.

[0075] In some embodiments, reference Figure 6 , along the direction perpendicular to the cutting surface 110, that is, in the second direction X, there is a height difference H1 between the bottom surfaces 123 of the two overlapping rectangular portions 111. It should be noted that, in the case where the bottom surfaces 123 of the two overlapping rectangular portions 111 are not parallel to each other, the height difference H1 of the bottom surfaces 123 of the two rectangular portions 111 refers to: the height difference between the shallowest position of the bottom surface 123 of one rectangular portion 111 and the shallowest position of the bottom surface 123 of the other rectangular portion 111.

[0076] In some embodiments, reference Figure 6, along the direction perpendicular to the cutting surface 110 (second direction X), the height difference H1 between the bottom surfaces 123 of any two overlapping rectangular portions 111 is 10nm~500nm. For example, it can be: 10nm, 60nm, 110nm, 120nm, 150nm, 170nm, 210nm or 300nm. In other embodiments, along the direction perpendicular to the cutting surface 110, the height difference H1 between the bottom surfaces 123 of the two overlapping rectangular portions 111 can be in the following range: 10nm~50nm, 50nm~100nm, 100nm~150nm, 150nm~200nm, 200nm~250nm, 250nm~300nm, 300nm~350nm, 350nm~400nm, 400nm~450nm or 450nm~500nm. If the height difference H1 between the two overlapping rectangular portions 111 is too large, the specific surface area of ​​the split battery 100 may be too large, that is, the surface area of ​​the cut surface 110 may be larger, which in turn may lead to more dangling bonds and recombination centers on the cut surface 110 formed by the cutting process. Therefore, the height difference H1 between the bottom surfaces 123 of the two overlapping rectangular portions 111 is less than 500nm, which is conducive to ensuring that the cut surface 110 has fewer dangling bonds and recombination centers.

[0077] In some embodiments, reference Figure 4 , at least one rectangular portion 111 includes a long side 120 and a wide side 121, the dimension L2 of the long side 120 is a first dimension, the dimension L1 of the wide side 121 is a second dimension, the product of the first dimension and the second dimension is a first value, and for any rectangular portion 111, the ratio of the area value of the bottom surface 123 of the rectangular portion 111 to the first value is 10% to 90%, for example, it can be 10%, 30%, 50%, 70% or 90%. In other embodiments, for any rectangular portion 111, the ratio of the area value of the bottom surface 123 of the rectangular portion 111 to the first value can also be 10% to 30%, 30% to 50%, 50% to 70% or 70% to 90%. The ratio of the area value of the bottom surface 123 of a rectangular portion 111 to the first value can represent the size of the portion of the rectangular portion 111 that is not overlapped by another rectangular portion 111.

[0078] In some embodiments, the density of the rectangular portion 111 located on the cutting surface 110 is 10 3 ~10 5 / mm 2 , 10 3 ~10 4 / mm 2 or 10 4 ~10 5 / mm 2 , for example: 10 3 / mm 2 , 10 4 / mm 2 or 10 5 / mm 2 It should be noted that the density of the rectangular portions 111 located on the cutting surface 110 is the number of rectangular portions 111 on the cutting surface 110 per unit area, and the unit area is 1 mm 2 If the density of the rectangular portions 111 on the cutting surface 110 is too large, the surface area of ​​the cutting surface 110 may be too large, resulting in more dangling bonds and composite centers on the cutting surface 110 formed by the cutting process. If the density of the rectangular portions 111 on the cutting surface 110 is too small, the area occupied by other structures with a large degree of concavity on the cutting surface 110 may be too large, resulting in more dangling bonds and composite centers on the cutting surface 110 formed by the cutting process. Therefore, along the direction perpendicular to the cutting surface 110, the density of the rectangular portions 111 located on the cutting surface 110 is within the above range, which is conducive to ensuring that the number of rectangular portions 111 on the cutting surface 110 is within a reasonable range, and avoiding the increase in the surface area of ​​the cutting surface 110 caused by the rectangular portions 111 being too dense or too sparse. This is conducive to ensuring that the cutting surface 110 has fewer dangling bonds and composite centers.

[0079] In some embodiments, reference Figure 4 , the rectangular portion 111 includes a long side 120 and a wide side 121, and along the extension direction of the long side 120, the size L2 of the long side 120 is 3μm~15μm, and / or, along the extension direction of the wide side 121, the size L1 of the wide side 121 is 3μm~15μm. In some examples, along the extension direction of the long side 120, the size L2 of the long side 120 may be 3μm, 4μm, 5μm, 6μm, 7μm or 11μm; in some examples, along the extension direction of the wide side 121, the size L1 of the wide side 121 may be 3μm, 4μm, 5μm, 6μm, 7μm or 11μm. In other embodiments, along the extension direction of the long side 120, the size L2 of the long side 120 may be in the following ranges: 3μm~6μm, 6μm~9μm, 9μm~12μm or 12μm~15μm. In other embodiments, along the extension direction of the wide side 121 , the size L1 of the wide side 121 may be in the following ranges: 3 μm to 6 μm, 6 μm to 9 μm, 9 μm to 12 μm, or 12 μm to 15 μm.

[0080] Compared with the situation where there are more irregular protruding structures or concave structures on the cutting surface 110, and the protruding structures are higher and the concave structures are deeper, the embodiment of the present application adopts a rectangular portion 111 as the structure on the cutting surface 110, which is beneficial to reducing the specific surface area of ​​the slice battery 100, that is, it is beneficial to reduce the flatness of the cutting surface 110 formed by cutting the slice battery 100, so that the surface area of ​​the cutting surface 110 formed by cutting is smaller, which is beneficial to reducing the dangling bonds and the recombination center on the surface of the cutting surface 110, and is beneficial to reducing the recombination current at the edge of the slice battery 100, thereby improving the performance of the slice battery 100.

[0081] Accordingly, another aspect of the present application embodiment further provides a method for forming a slice battery, which can be used to form the slice battery provided in the above embodiment. It should be noted that the parts that are the same or corresponding to the above embodiment can refer to the detailed description of the above embodiment, and will not be repeated below.

[0082] A method for forming a sliced ​​battery includes: providing a whole battery; slicing the whole battery to form a sliced ​​battery, wherein the sliced ​​battery has a cutting surface formed by the slicing process; wherein at least part of the cutting surface has a first texture structure, the first texture structure includes at least a plurality of rectangular portions, and at least one rectangular portion partially overlaps with at least another adjacent rectangular portion.

[0083] In some embodiments, the slicing process includes: laser grooving the whole cell using a laser grooving process to form grooves on a portion of the surface of the whole cell, the laser wavelength of the laser grooving process is 500nm~1000nm, for example, it can be: 500nm, 600nm, 700nm, 800nm ​​or 900nm. In other embodiments, the laser wavelength of the laser grooving process can be in the following range: 500nm~600nm, 600nm~700nm, 700nm~800nm ​​or 800nm~900nm.

[0084] In some embodiments, the laser pulse width of the laser slotting process is 10ns~1000ns, for example, it can be: 10ns, 100ns, 200ns, 300ns, 500ns or 800ns. In other embodiments, the laser pulse width of the laser slotting process can be in the following ranges: 10ns~200ns, 200ns~400ns, 400ns~600ns, 600ns~800ns or 800ns~1000ns.

[0085] In some embodiments, the laser power of the laser slotting process is 50 W to 100 W, for example, 50 W, 60 W, 70 W, 80 W or 90 W. In other embodiments, the laser power of the laser slotting process may also range from 50 W to 60 W, 60 W to 70 W, 70 W to 80 W, 80 W to 90 W or 90 W to 100 W.

[0086] The parameters of the laser grooving process are within the above range, which is conducive to forming a cutting surface with higher flatness including the rectangular portion, so that the surface area of ​​the cutting surface formed by cutting is smaller, which is conducive to reducing the dangling bonds and recombination centers on the surface of the cutting surface, and is conducive to reducing the recombination current at the edge of the slice battery, thereby improving the performance of the slice battery.

[0087] Laser grooving is used to form grooves on the whole battery for dividing the whole battery. The whole battery is then broken from the groove to obtain split batteries.

[0088] In some embodiments, the slicing process further includes: heating the groove using a laser heating process, wherein the laser heating process locally heats the groove, making it easier to break the entire battery from the groove.

[0089] In some embodiments, the laser wavelength of the laser heating process is 500nm~1000nm, for example, it can be: 500nm, 600nm, 700nm, 800nm ​​or 900nm. In other embodiments, the laser wavelength of the laser heating process can be in the following ranges: 500nm~600nm, 600nm~700nm, 700nm~800nm ​​or 800nm~900nm.

[0090] In some embodiments, the laser pulse width of the laser heating process is 10ns~1000ns, for example, it can be: 10ns, 100ns, 200ns, 300ns, 500ns or 800ns. In other embodiments, the laser pulse width of the laser heating process can be in the following ranges: 10ns~200ns, 200ns~400ns, 400ns~600ns, 600ns~800ns or 800ns~1000ns.

[0091] In some embodiments, the laser power of the laser heating process is 20W-50W. For example, it can be: 20W, 25W, 30W, 35W or 45W. In other embodiments, the laser power of the laser heating process can also range from 20W-30W, 30W-40W or 40W-50W.

[0092] The parameters of the laser heating process are within the above range, which is conducive to forming a cutting surface with higher flatness including the rectangular portion, so that the surface area of ​​the cutting surface formed by cutting is smaller, which is conducive to reducing the dangling bonds and recombination centers on the surface of the cutting surface, and is conducive to reducing the recombination current at the edge of the slice battery, thereby improving the performance of the slice battery.

[0093] In the slice battery obtained by cutting using the slice battery formation method provided by the above embodiment, the surface structure on the cutting surface includes a rectangular portion, the slice battery has a smaller specific surface area, the flatness of the cutting surface is higher, and the surface area of ​​the cutting surface is smaller, which is beneficial to reducing the dangling bonds and recombination centers on the surface of the cutting surface, and is beneficial to reducing the recombination current at the edge of the slice battery, thereby improving the performance of the slice battery.

[0094] Correspondingly, an embodiment of the present application also provides a photovoltaic module, including: a battery string, the battery string includes the sliced ​​battery of any one of the above embodiments; a packaging film, the packaging film is used to cover the surface of the battery string; and a cover plate, the cover plate is used to cover the surface of the packaging film away from the battery string.

[0095] In some embodiments, adjacent slice batteries are connected via a connecting component. The connecting component is located in the slice battery and the main grid is away from the surface of the battery body and is in electrical contact with the main grid. One end of the connecting component is electrically connected to the main grid of one slice battery, and the other end of the connecting component is electrically connected to the main grid of another adjacent slice battery. The connecting component can be welded to the welding portion of the main grid to electrically connect the connecting component to the main grid, and multiple slice batteries are connected in series via the connecting component.

[0096] The connecting component can be composed of a conductive layer and a welding layer wrapping the surface of the conductive layer. The material of the conductive layer includes conductive materials with good conductivity such as copper, nickel, gold, silver, or alloy materials with low resistivity; the material of the welding layer includes materials with low melting points such as tin-zinc alloy, tin-bismuth alloy or tin-indium alloy.

[0097] In some embodiments, the soldering layer may have a soldering flux, which refers to a chemical substance that can help and promote the soldering process in the soldering process and has a protective effect and prevents oxidation reactions. Since the melting point of the soldering flux is lower than the melting point of the soldering layer, the soldering flux can help increase the fluidity of the soldering layer in a molten state so that the connecting component and the grid line structure can be better alloyed. In some embodiments, the soldering flux includes an inorganic soldering flux, an organic soldering flux, and a resin soldering flux.

[0098] In some embodiments, the encapsulation film may be an organic encapsulation film such as an ethylene-vinyl acetate copolymer film, a polyethylene-octene co-elastic film or a polyvinyl butyral film. On the one hand, the encapsulation film can prevent the photovoltaic cell from being damaged by a harsh environment (such as rain, snow, sand, dust, heat, etc.), thereby improving the durability of the photovoltaic cell and extending the life of the photovoltaic cell; on the other hand, the encapsulation film can also prevent the formation of an oxide layer on the surface of the photovoltaic cell to ensure the highest efficiency of electrical energy conversion.

[0099] In some embodiments, the cover plate may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. The cover plate can prevent the photovoltaic cells from being affected by the environment and improve the service life and stability of the photovoltaic module.

[0100] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art may make their own changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A split battery, characterized in that: include: The sliced ​​battery is formed by slicing the whole battery, and the sliced ​​battery has a cutting surface formed by the slicing process; Wherein, at least part of the cutting surface has a first texture structure, the first texture structure at least includes a plurality of rectangular portions, and at least one of the rectangular portions partially overlaps with at least one adjacent rectangular portion; The rectangular portion is recessed toward the split battery, the bottom surface of the rectangular portion is a plane, and along the direction perpendicular to the cutting surface, there is a height difference between the bottom surfaces of the two overlapping rectangular portions, the height difference between the bottom surfaces of the two overlapping rectangular portions is 10nm~500nm, the depth of the rectangular portion recessed toward the split battery is 10nm~500nm, and the angle between the bottom surface and the cutting surface is less than 30°.

2. The split battery according to claim 1, characterized in that: Any of the rectangular portions is adjacent to at least one of the rectangular portions, and any of the rectangular portions partially overlaps with at least one of the adjacent rectangular portions.

3. The split battery according to claim 2, characterized in that: The rectangular portion includes a long side and a wide side, the size of the long side is a first size, the size of the wide side is a second size, the product of the first size and the second size is a first value, and for any of the rectangular portions, the ratio of the area value of the bottom surface of the rectangular portion to the first value is 10% to 90%.

4. The split battery according to claim 1, characterized in that: The density of the rectangular portion located on the cutting surface is 10 3 ~10 5 / mm 2 .

5. The split battery according to claim 1, characterized in that: The rectangular portion includes a long side and a wide side. Along the extension direction of the long side, the size of the long side is 3 μm to 15 μm, and / or, along the extension direction of the wide side, the size of the wide side is 3 μm to 15 μm.

6. A photovoltaic module, characterized in that: include: A battery string, the battery string comprising the sliced ​​battery according to any one of claims 1 to 5; A packaging film, the packaging film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the packaging film away from the battery string.

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