Battery piece manufacturing method and solar battery

Abstract

The embodiment of the invention provides a manufacturing method of a battery piece and a solar cell, and the method comprises the steps: providing an initial battery piece; cutting the initial battery piece to form a slice battery piece with at least one cutting surface; forming a first passivation layer, wherein the first passivation layer at least covers the cutting surface of a part of the sliced battery piece; forming a second passivation layer, wherein the second passivation layer at least covers the surface of the first passivation layer; forming a third passivation layer, wherein the third passivation layer at least covers the surface of the second passivation layer; forming a fourth passivation layer, wherein the fourth passivation layer at least covers the surface of the third passivation layer; wherein the first passivation layer is made of semiconductor oxide, the second passivation layer is made of metal semiconductor oxide, the third passivation layer and the fourth passivation layer are made of metal oxide, the density of the third passivation layer is larger than that of the fourth passivation layer, the thickness of the third passivation layer is smaller than that of the fourth passivation layer, and battery efficiency and production efficiency can be both considered.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a method for manufacturing a cell and a solar cell. Background Art

[0002] In order to reduce the power reduction and hot spots of photovoltaic modules caused by differences in the electrical performance of the batteries, the high current of the whole solar cell can easily lead to significant resistance loss. In order to improve the problem of large power loss of the whole solar cell, half-cell, shingled and other forms of photovoltaic modules are constantly favored by terminal module manufacturers and users.

[0003] However, whether it is a half-cell module or a shingled module, laser cutting technology is required to cut the entire solar cell into half or multiple small slices of cells. The cell after slicing has a reduced efficiency due to mechanical damage during the slicing process and the presence of dangling bonds on the cut surface, thereby reducing the module power. Summary of the invention

[0004] The embodiments of the present disclosure provide a method for manufacturing a solar cell and a solar cell, which can at least take into account both the battery efficiency and the production efficiency.

[0005] According to some embodiments of the present disclosure, on the one hand, the embodiments of the present disclosure provide a method for manufacturing a battery cell, comprising: providing an initial battery cell; cutting the initial battery cell to form a sliced ​​battery cell having at least one cutting surface; forming a first passivation layer, the first passivation layer at least covers a portion of the cutting surface of the sliced ​​battery cell; forming a second passivation layer, the second passivation layer at least covers a side surface of the first passivation layer away from the sliced ​​battery cell; forming a third passivation layer, the third passivation layer at least covers a side surface of the second passivation layer away from the first passivation layer; forming a fourth passivation layer, the fourth passivation layer at least covers a side surface of the third passivation layer away from the second passivation layer; wherein the material of the first passivation layer is semiconductor oxide, the material of the second passivation layer is metal semiconductor oxide, the materials of the third passivation layer and the fourth passivation layer are metal oxides, and the third passivation layer and the fourth passivation layer adopt different processes so that the density of the third passivation layer is greater than that of the fourth passivation layer, and the thickness of the third passivation layer is less than that of the fourth passivation layer.

[0006] In some embodiments, the process of forming the third passivation layer includes: forming the third passivation layer by an atomic layer deposition process, and the process parameters for forming the third passivation layer include: process temperature: 150-350°C, and sequentially introducing a gas source containing metal elements, nitrogen, water vapor / nitrogen and nitrogen, each gas flow rate is 500-3000sccm, the time for each gas introduction is 3-15s, and the gas is introduced 10-600 times.

[0007] In some embodiments, the method of forming the second passivation layer includes: during the process of forming the third passivation layer, controlling the diffusion of metal elements of the third passivation layer into a portion of the first passivation layer to convert a portion of the first passivation layer into the second passivation layer.

[0008] In some embodiments, the process of forming the fourth passivation layer includes: forming the fourth passivation layer by chemical vapor deposition, and the process parameters for forming the fourth passivation layer include: process temperature: 150~600℃, while introducing a gas source containing a metal element, a gas source containing an oxygen element and nitrogen, each gas flow rate is 300~2000sccm, and plasma is excited.

[0009] In some embodiments, the sliced ​​battery cell includes a substrate, and the method for forming the first passivation layer includes: oxidizing the cut surface of the sliced ​​battery cell to convert a portion of the substrate of the sliced ​​battery cell into the first passivation layer, and the process parameters for forming the first passivation layer include: process temperature: 100~150℃, the gas flow rate of the water vapor is 1000~2000sccm, and the duration is 5~60s.

[0010] In some embodiments, the process parameters for cutting the initial battery sheet include: the process parameters for cutting the initial battery sheet include: laser power 80-100w, water flow 1-5ml, and cutting angle 45-90°.

[0011] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a solar cell, comprising: sliced ​​solar cells, at least two of the sliced ​​solar cells are formed by cutting the same whole solar cell, and the sliced ​​solar cells have a cutting surface; a first passivation layer, the first passivation layer at least covers a portion of the cutting surface of the sliced ​​solar cell; a second passivation layer, the second passivation layer at least covers a side surface of the first passivation layer away from the sliced ​​solar cell; a third passivation layer, the third passivation layer at least covers a side surface of the second passivation layer away from the first passivation layer; a fourth passivation layer, the fourth passivation layer at least covers a side surface of the third passivation layer away from the second passivation layer; wherein the material of the first passivation layer is semiconductor oxide, the material of the second passivation layer is metal semiconductor oxide, the materials of the third passivation layer and the fourth passivation layer are metal oxides, the density of the third passivation layer is greater than that of the fourth passivation layer, and the thickness of the third passivation layer is less than that of the fourth passivation layer.

[0012] In some embodiments, the metal element of the second passivation layer is the same as the metal element of the third passivation layer, and the doping concentration of the metal element of the second passivation layer is less than the doping concentration of the metal element of the third passivation layer.

[0013] In some embodiments, the thickness of the third passivation layer is 5 to 15 nm, and / or the thickness of the fourth passivation layer is 20 to 100 nm.

[0014] In some embodiments, the sliced ​​battery sheet includes a front side and a back side opposite to each other, and the angle between the cutting surface and the front side or the back side is an acute angle.

[0015] The technical solution provided by the embodiments of the present disclosure has at least the following advantages:

[0016] On the one hand, a first passivation layer, a second passivation layer, a third passivation layer and a fourth passivation layer are sequentially formed on the cross section. The passivation effect on the cross section can be improved by multi-layer stacking. Moreover, the third passivation layer and the fourth passivation layer are metal oxides. Metal oxides have good chemical passivation ability and field effect passivation ability, which can improve the performance of the formed battery cell.

[0017] On the other hand, for the third passivation layer and the fourth passivation layer, the third passivation layer and the fourth passivation layer exposed to the air may absorb water vapor in the air, or adsorb particles in the air, causing the third passivation layer and the fourth passivation layer to fail. Therefore, the third passivation layer and the fourth passivation layer need to have a certain thickness and density to have a good passivation effect. However, for the metal oxide layer, if only the density is considered, a longer process time will be required, which will greatly affect the output. If only the thickness is considered, the metal oxide layer will fail. Therefore, different processes are used when forming the third passivation layer and the fourth passivation layer to form a third passivation layer with a higher density and a fourth passivation layer with a thicker thickness. Reliability and production efficiency can be taken into account at the same time, thereby taking into account the battery efficiency and production efficiency of the formed battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figures 1 to 5 A schematic diagram of the structures corresponding to each step of a method for manufacturing a battery cell provided in one embodiment of the present disclosure;

[0020] Figure 6A schematic diagram of the structure of a photovoltaic module provided by an embodiment of the present disclosure;

[0021] Figure 7 A schematic cross-sectional view of a photovoltaic module provided in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0022] As known from the background art, the photoelectric conversion efficiency of solar cells after cutting needs to be improved.

[0023] After analysis, it was found that in order to improve the problem of large power loss of the whole solar cell, laser cutting technology is used to cut the whole solar cell into half or multiple small slices of cells, and then the sliced ​​cells are connected in series using conductive welding ribbons. The series current is lower than the current of the whole cell. The current reduction of the sliced ​​cells can improve the power loss of the photovoltaic module.

[0024] However, during the laser slicing process, if the laser partially melts the entire solar cell along a set path, and then mechanical force is used to crack the cell along the set path to achieve slicing, a cut surface will be left on the sliced ​​cell, and a laser damage area and a mechanical fracture area will be formed on the cut surface, resulting in the silicon atoms at the cut surface being unable to maintain their original ordered arrangement state, and there are a large number of defect states, which become effective recombination centers for carriers. A large number of carriers recombine based on the recombination centers, seriously reducing the photoelectric conversion efficiency of the sliced ​​cell.

[0025] The embodiments of the present disclosure provide a method for manufacturing a cell, a solar cell and a photovoltaic module. In the method for manufacturing a cell, on the one hand, a first passivation layer, a second passivation layer, a third passivation layer and a fourth passivation layer are sequentially formed on a cross section, and the passivation effect on the cross section can be improved by stacking multiple layers. Moreover, the third passivation layer and the fourth passivation layer are metal oxides, which have good chemical passivation ability and field effect passivation ability, and can improve the performance of the formed cell; on the other hand, for the third passivation layer and the fourth passivation layer, the third passivation layer and the fourth passivation layer exposed to the air may absorb water vapor in the air, or absorb Particles in the attached air cause the third passivation layer and the fourth passivation layer to fail. Therefore, the third passivation layer and the fourth passivation layer need to have a certain thickness and density to have a good passivation effect. However, for the metal oxide layer, if only the density is considered, a longer process time will be required, which will greatly affect the output. If only the thickness is considered, the metal oxide layer will fail. Therefore, different processes are used when forming the third passivation layer and the fourth passivation layer to form a third passivation layer with a higher density and a fourth passivation layer with a thicker thickness. Reliability and production efficiency can be taken into account at the same time, thereby taking into account the battery efficiency and production efficiency of the formed battery cell.

[0026] In the description of the embodiments of the present disclosure, 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 disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0027] 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 disclosure. The appearance of the phrase in various places 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.

[0028] In the description of the embodiments of the present disclosure, 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 may 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.

[0029] In the description of the embodiments of the present disclosure, 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).

[0030] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0031] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0032] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a 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 being "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.

[0033] In the description of the embodiments of the present disclosure, 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, a film, a region, or a plate is referred to as being "on / located on" another component, it may 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, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0034] 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, "the components" are also intended to include plural forms unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0035] The following will describe the various embodiments of the present disclosure 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 disclosure, many technical details are provided in order to enable the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can be implemented.

[0036] refer to Figures 1 to 5 , Figures 1 to 5 A schematic diagram of the structure corresponding to each step of a solar cell provided by an embodiment of the present disclosure.

[0037] refer to Figure 1 , Figure 1 1 is a schematic diagram of the structure of an initial battery cell. In some implementations, a method for manufacturing a battery cell may include: providing an initial battery cell 100 .

[0038] The initial cell 100 includes, but is not limited to, one or any combination of PERC cells (Passivated Emitter Rear Cell), IBC cells (Interdigitated Back Contact), TOPCon cells (Tunnel Oxide Passivated Contact), HIT / HJT cells (Heterojunction Technology), solar thin-film cells, and stacked cells. The solar thin-film cells include, but are not limited to, perovskite solar thin-film cells, copper indium selenide solar thin-film cells, gallium arsenide solar thin-film cells, and cadmium sulfide solar thin-film cells. The stacked cells include, but are not limited to, perovskite cells stacked with crystalline silicon cells, perovskite cells stacked with perovskite cells, and perovskite cells stacked with thin-film cells.

[0039] Taking TOPCon cells as an example, the initial cell 100 may have formed a front emitter 120 , a front passivation layer 130 , a front electrode 140 , a back oxide layer 150 , a back doped conductive layer 160 , a back passivation layer 170 and a back electrode 180 on the surface of a substrate 110 .

[0040] refer to Figure 2 , Figure 2 For Figure 1 The structural schematic diagram of the sliced ​​battery cell is formed on the basis of the above, and the method for manufacturing the battery cell may further include: cutting the initial battery cell 100 to form a sliced ​​battery cell 101 having at least one cutting surface 111.

[0041] It is understandable that for the sliced ​​cell 101, the sliced ​​cell 101 can also have a substrate 110, a front emitter 120, a front passivation layer 130, a front electrode 140, a back oxide layer 150, a back doped conductive layer 160, a back passivation layer 170 and a back electrode 180.

[0042] In some embodiments, the method of cutting the initial battery cell 100 may include: cutting by laser.

[0043] The process parameters for cutting the initial battery cell 100 may include: laser power 80~100w, for example 80w, 85, 90w, 93w or 98w, etc., water flow 1~5ml, for example 1ml, 2ml, 3ml, 4ml or 5ml, etc., cutting angle 45~90°, for example 60°, 70°, 80° or 85°, etc.

[0044] Regarding laser power, the greater the laser power, the faster the cutting speed, but the greater the damage to the sliced ​​battery cell formed. Therefore, by setting the laser power to 80-100w, the process efficiency can be guaranteed while ensuring the reliability of the sliced ​​battery cell 101 formed.

[0045] As for the water flow rate, the water flow is used to cool down the initial cell 100 during cutting, thereby protecting the cell. Therefore, by setting the water flow rate to 1-5 ml, the damage to the sliced ​​cell can be minimized as much as possible without affecting the cutting process.

[0046] The cutting angle can be adjusted according to needs. The smaller the cutting angle, the more favorable it is to reduce the probability of carrier recombination on the cutting surface. However, the smaller the cutting angle, the more it will affect the reliability of the formed sliced ​​battery cell 101. Therefore, the cutting angle is set to 45~90° to take into account the reliability and performance of the formed sliced ​​battery cell 101.

[0047] refer to Figure 3 , Figure 3 For Figure 2 The first passivation layer is formed on the basis of the cell, and the method for manufacturing the cell may further include: forming a first passivation layer 102 , the first passivation layer 102 at least covering a portion of the cut surface 111 of the sliced ​​cell 101 .

[0048] In some embodiments, the method of forming the first passivation layer 102 may include: oxidizing the cut surface 111 of the sliced ​​cell 101 to convert the substrate 110 of a portion of the sliced ​​cell 101 into the first passivation layer 102. Oxidation of the substrate 110 can repair the cut surface 111 on the one hand, thereby reducing the recombination center of the carriers; on the other hand, the film layer formed by oxidation of the substrate 110 has a high density, which can improve the passivation effect of the first passivation layer 102.

[0049] The process parameters for forming the first passivation layer 102 may include: process temperature: 100-150°C, for example, 110°C, 120°C, 130°C or 140°C, gas flow rate of water vapor is 1000-2000sccm, for example, 1200sccm, 1400sccm, 1600sccm, 1700sccm or 1900sccm, duration is 5-60s, for example, 10s, 20s, 30s, 40s or 50s, etc.

[0050] Regarding the process temperature, the higher the process temperature, the faster the rate of forming the first passivation layer 102 is, but the depth of the first passivation layer 102 passivating the sliced ​​solar cell is also higher. Therefore, setting the process temperature to 100-150°C can improve the process efficiency while avoiding affecting the photoelectric conversion efficiency of the sliced ​​solar cell.

[0051] Regarding the gas flow rate of the water vapor, it can be understood that the cutting surface of the sliced ​​battery cell 10 has a certain reaction area. Based on this, there is a certain reaction upper limit for the rate of forming the first passivation layer 102. Setting the gas flow rate of the water vapor to 1000-2000 sccm can make the entire passivation process have a certain rate while avoiding the waste of water vapor.

[0052] As for the process time, the longer the process time is, the thicker the first passivation layer 102 will be. Therefore, setting the process time to 5 to 60 seconds can ensure that the first passivation layer 102 has a certain thickness while preventing the first passivation layer from affecting the photoelectric conversion efficiency of the sliced ​​solar cells.

[0053] For the process of forming the first passivation layer 102 by oxidation, the oxidation process will also oxidize a portion of the front emitter 120 and a portion of the back doped conductive layer 160 .

[0054] In some embodiments, the method for forming the first passivation layer 102 may further include: forming the first passivation layer 102 directly on the surface of the cut surface 111 by deposition. Compared with the method of oxidizing the substrate 110, the deposition method can avoid the oxidation thickness of the substrate 110 being too deep during the oxidation process, and avoid excessive impact on the ability of the substrate 110 to generate photogenerated carriers. Moreover, the thickness of the formed first passivation layer 102 can also be controlled by deposition. Compared with the oxidation method, the deposition method can more accurately control the first passivation layer 102 to the desired thickness.

[0055] For the process of forming the first passivation layer 102 by deposition, the formed first passivation layer 102 not only covers the side walls of the substrate 110, but also covers the side walls of the front emitter 120, the front passivation layer 130, the front electrode 140, the back oxide layer 150, the back doped conductive layer 160, the back passivation layer 170 and the back electrode 180.

[0056] In some embodiments, the material of the first passivation layer 102 is set to be a semiconductor oxide, such as a silicon oxide material, and the oxygen atoms of the first passivation layer 102 saturate the dangling bonds on the cutting surface 111 to reduce the defect state density of the cutting surface 111 and reduce the recombination centers of the cutting surface 111 to reduce the probability of carrier recombination.

[0057] In some embodiments, when the initial battery cell 100 is cut, the cut surface 111 formed is at an acute angle to a surface of the substrate 110, that is, an inclined cut surface 111 is formed. The atomic arrangement density on the inclined cut surface 111 is smaller, and the covalent bond surface density is smaller, so the connection between adjacent atoms on the cut surface 111 is not firm, which is more conducive to promoting the first passivation layer 102 located on the cut surface 111 to bond with the dangling bonds on the cut surface 111, that is, making it easier for the first passivation layer 102 to saturate the dangling bonds on the cut surface 111, and the first passivation layer 102 can also passivate other surface defects on the cut surface 111, which is conducive to further improving the ability of the first passivation layer 102 to reduce the defect state density of the cut surface 111, so as to further reduce the recombination center of the cut surface 111 to reduce the probability of carrier recombination. In other words, designing the cut surface 111 of the sliced ​​cell to be inclined rather than perpendicular to its back side and cooperating with the passivation function of the first passivation layer 102 is beneficial to further improve the passivation effect of the first passivation layer 102 on the cut surface 111, so as to further reduce the probability of carrier recombination on the cut surface 111, increase the life of the carriers, and thus further improve the photoelectric conversion efficiency of the sliced ​​cell.

[0058] refer to Figure 4 , Figure 4 exist Figure 3 A second passivation layer is formed on the basis of the first passivation layer 102. The method for manufacturing the battery cell may also include: forming a second passivation layer 103, the second passivation layer 103 at least covers the surface of the first passivation layer 102 away from the sliced ​​battery cell 101; forming a third passivation layer 104, the third passivation layer 104 at least covers the surface of the second passivation layer 103 away from the first passivation layer 102.

[0059] In some embodiments, the process of forming the third passivation layer 104 includes: forming the third passivation layer 104 using an atomic layer deposition process, the film thickness of the third passivation layer 104 formed using the atomic layer deposition process is controllable and uniform, highly consistent with the surface shape of the cutting surface 111, and the defect density of the third passivation layer 104 formed using the atomic layer deposition process is low.

[0060] In some embodiments, the process parameters for forming the third passivation layer 104 may include a process temperature of 150 to 350°C, for example, 200°C, 230°C, 250°C, 300°C, 320°C or 340°C, and a gas source containing a metal element, nitrogen, water vapor / nitrogen and nitrogen are introduced in sequence, with a gas flow rate of 500 to 3000sccm for each gas, for example, 1000sccm, 1500sccm, 1800sccm, 2200sccm, 2500sccm or 2800sccm, and the time for each gas introduction is 3 to 15s, for example, 6s, 7s, 10s, 12s, 13s or 14s, and the gas is introduced 10 to 600 times, for example, 100 times, 150 times, 200 times, 250 times, 300 times, 400 times or 500 times, and so on.

[0061] Regarding the process temperature, the higher the process temperature, the faster the rate of forming the third passivation layer 104 is, but the thickness of the third passivation layer 104 is more uncontrollable. Therefore, setting the process temperature to 150-350°C can improve the process efficiency while forming the third passivation layer 104 of the required thickness.

[0062] For the gas source, a metal element gas source, nitrogen, water vapor / nitrogen and nitrogen are introduced in sequence by controlling the gas flow rate of each gas is 500-3000sccm, the time for each gas introduction is 3-15s, and the gas introduction rounds are 10-600 rounds. By introducing a metal element gas source, nitrogen, water vapor / nitrogen and nitrogen in sequence, a third passivation layer 104 formed by stacking several film layers is formed, thereby improving the density and reliability of the third passivation layer.

[0063] In some embodiments, the process temperature for forming the third passivation layer 104 is 200-300°C, and the gas flow rate of each gas is 1500-2000sccm. For the third passivation layer 104, the area of ​​the formed interface is certain, and the formation rate has a certain upper limit. At this temperature and this gas flow rate, the rate of the third passivation layer can be increased while avoiding the waste of each gas.

[0064] The material of the third passivation layer 104 is a metal oxide material, wherein the metal element includes at least one of Al element, Ti element, Zn element, Zr element or Hf element, all of which can make the third passivation layer 104 have a high density of fixed negative charge to perform a good field passivation effect on the cutting surface 111; the metal element in the metal oxide material includes at least one of Mo element, W element or Ni element, all of which can make the third passivation layer 104 have a high density of fixed positive charge or a high work function to perform a good field passivation effect on the cutting surface 111.

[0065] In some embodiments, the method of forming the second passivation layer 103 includes: during the formation of the third passivation layer 104 , controlling the diffusion of metal elements of the third passivation layer 104 into a portion of the first passivation layer 102 to convert a portion of the first passivation layer 102 into the second passivation layer 103 .

[0066] On the one hand, by diffusing the metal elements of the third passivation layer 104 into the first passivation layer 102 to form the second passivation layer 103, the process steps of the battery cell manufacturing method can be reduced, thereby reducing the cost of the entire battery cell; on the other hand, the second passivation layer 103 is used as an intermediate layer from the first passivation layer 102 to the third passivation layer 104, and the second passivation layer is controlled to have both the same semiconductor elements as the first passivation layer and the same metal elements as the third passivation layer 104. In this way, the second passivation layer 103 is conducive to the semiconductor element. The conductor elements make the lattice at the interface where the second passivation layer 103 and the first passivation layer 102 are in contact more adapted, and are also beneficial for using metal elements to make the lattice at the interface where the second passivation layer 103 and the third passivation layer 104 are in contact more adapted, which is beneficial for avoiding the problem of lattice adaptation between the first passivation layer 102 and the third passivation layer 104 when the first passivation layer 102 and the third passivation layer 104 are in direct contact, thereby avoiding the problem of increase or decrease of surface defects caused by lattice mismatch, thereby improving the passivation effect on the cut surface 111 of the battery cell.

[0067] In other words, the second passivation layer 103 plays a transition role to improve the adaptability of the lattice at the interface where the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104 are in contact with each other in sequence, and prevent the occurrence of gaps and dislocations at the interface where the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104 are in contact with each other in sequence, so as to improve the uniformity of the overall film layer of the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104, thereby improving the overall interface passivation effect of the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104 on the sliced ​​battery cell 101. Moreover, it is helpful to improve the connection strength between the first passivation layer 102 and the third passivation layer 104 with the help of the second passivation layer 103, so as to avoid the mutual slippage or falling off problem of the first passivation layer 102 and the second passivation layer 103, or the second passivation layer 103 and the third passivation layer 104, thereby helping to improve the overall structural stability of the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104.

[0068] In some embodiments, the content of metal elements in the second passivation layer 103 gradually decreases in the direction from the third passivation layer 104 to the first passivation layer 102, and the content of semiconductor elements in the second passivation layer 103 gradually decreases in the direction from the first passivation layer 102 to the third passivation layer 104. In this way, the semiconductor element content at the interface where the second passivation layer 103 and the first passivation layer 102 are in contact can be controlled to be the highest, and the metal element content at the interface where the second passivation layer 103 and the third passivation layer 104 are in contact can be controlled to be the highest. The adaptability of the lattice at the interface where the second passivation layer 103 and the first passivation layer 102 are in contact can be further improved, and the adaptability of the lattice at the interface where the second passivation layer 103 and the third passivation layer 104 are further improved, thereby further improving the overall passivation effect of the first passivation layer 102, the second passivation layer 103 and the third passivation layer 104.

[0069] It should be noted that the gradual decrease in the content of the above-mentioned elements may mean that the content of the elements gradually decreases in the normal direction of the interface where the second passivation layer 103 contacts the first passivation layer 102, or it may mean that within a predetermined thickness, the average content of the elements in the second passivation layer 103 gradually decreases in the normal direction of the interface where the second passivation layer 103 contacts the first passivation layer 102.

[0070] In some embodiments, the method of forming the second passivation layer 103 and the third passivation layer 104 may also include: forming the second passivation layer 103 on the surface of the first passivation layer 102 by deposition, and then forming the third passivation layer 104 on the surface of the second passivation layer 103 by deposition. The deposition method can facilitate the control of the thickness of the formed second passivation layer 103 and improve the uniformity of the film layer of the second passivation layer 103.

[0071] refer to Figure 5 , Figure 5 exist Figure 4 A fourth passivation layer is formed on the basis of the second passivation layer 103. The method for manufacturing the battery cell may also include: forming a fourth passivation layer 105, the fourth passivation layer 105 at least covers the surface of the third passivation layer 104 away from the second passivation layer 103; wherein the material of the fourth passivation layer 105 is metal oxide, and the third passivation layer 104 and the fourth passivation layer 105 are made of different processes so that the density of the third passivation layer 104 is greater than that of the fourth passivation layer 105, and the thickness of the third passivation layer 104 is less than that of the fourth passivation layer 105.

[0072] For the third passivation layer 104 and the fourth passivation layer 105, the third passivation layer 104 and the fourth passivation layer 105 need to have a certain thickness and density to have a good passivation effect. If only the density is considered, a longer process time will be required, which will greatly affect the yield. If only the thickness is considered, the metal oxide layer will fail. Therefore, when forming the fourth passivation layer 105, the process difficulty of the fourth passivation layer 105 is reduced by reducing the density of the fourth passivation layer 105 to increase the process speed of forming the fourth passivation layer 105, so that the third passivation layer 104 and the fourth passivation layer 105 as a whole consider both the density and the thickness of the film layer.

[0073] In some embodiments, the process of forming the fourth passivation layer 105 includes: forming the fourth passivation layer 105 by chemical vapor deposition. Chemical vapor deposition can quickly prepare a metal oxide layer with a certain thickness, so that the third passivation layer 104 and the fourth passivation layer 105 can have a certain thickness as a whole, so as to make full use of the fixed charges in the film layer to achieve field passivation, so as to improve the passivation effect of the third passivation layer 104 and the fourth passivation layer 105 as a whole.

[0074] In some embodiments, the process parameters for forming the fourth passivation layer 105 include: process temperature: 150-600°C, for example, 200°C, 300°C, 400°C, 450°C, 500°C or 550°C, etc., and at the same time, a gas source containing a metal element, a gas source containing an oxygen element and nitrogen are introduced, and the flow rate of each gas is 300-2000sccm, for example, 400sccm, 500sccm, 600sccm, 700sccm, 800sccm, 1000sccm, 1500sccm or 1800sccm, and plasma is excited.

[0075] The process parameters for forming the fourth passivation layer 105 are controlled to be a process temperature of 150 to 600°C, and a gas source containing a metal element, a gas source containing an oxygen element, and nitrogen are introduced at the same time, with a gas flow rate of 300 to 2000 sccm for each gas, and plasma is excited, thereby increasing the formation rate of the fourth passivation layer 105, thereby quickly forming a fourth passivation layer 105 with a certain thickness, so that the third passivation layer 104 and the fourth passivation layer 105 have a certain thickness as a whole, thereby improving the passivation ability and reliability of the third passivation layer 104 and the fourth passivation layer 105 as a whole, and by quickly forming the fourth passivation layer, the process time of the entire process can be reduced.

[0076] In some embodiments, the process temperature for forming the fourth passivation layer 105 is 400-500°C and the gas flow rate is 400sccm-800sccm. It can be understood that the area of ​​the formation surface of the third passivation layer 104 is certain, so there is a certain upper limit on the speed of forming the fourth passivation layer 105. At a temperature within this range and a gas flow rate within this range, the fourth passivation layer 105 can have a certain formation speed without wasting any gas.

[0077] The embodiment of the present disclosure provides a method for manufacturing a battery cell. On the one hand, a first passivation layer 102, a second passivation layer 103, a third passivation layer 104 and a fourth passivation layer 105 are sequentially formed on a cross section. The passivation effect on the cross section can be improved by stacking multiple layers. Moreover, the third passivation layer 104 and the fourth passivation layer 105 are metal oxides. The metal oxides have good chemical passivation ability and field effect passivation ability, which can improve the performance of the formed battery cell. On the other hand, for the third passivation layer 104 and the fourth passivation layer 105, the third passivation layer 104 and the fourth passivation layer 105 exposed to the air may absorb water vapor in the air, or adsorb particles in the air. , resulting in failure of the third passivation layer 104 and the fourth passivation layer 105. Therefore, the third passivation layer 104 and the fourth passivation layer 105 need to have a certain thickness and density to have a good passivation effect. However, for the metal oxide layer, if only the density is considered, a longer process time will be required, which will greatly affect the output. If only the thickness is considered, the metal oxide layer will fail. Therefore, different processes are used when forming the third passivation layer 104 and the fourth passivation layer 105 to form a third passivation layer 104 with a higher density and a fourth passivation layer 105 with a thicker thickness. Reliability and production efficiency can be taken into account at the same time, thereby taking into account the battery efficiency and production efficiency of the formed battery cell.

[0078] Another embodiment of the present disclosure further provides a solar cell, which can be formed by the above-mentioned cell manufacturing method. The solar cell provided by another embodiment of the present disclosure will be described below in conjunction with the accompanying drawings. It should be noted that the same or corresponding parts of the above-mentioned embodiments can refer to the corresponding description of the above-mentioned embodiments and will not be repeated below.

[0079] refer to Figure 5 In some embodiments, the solar cell includes: a sliced ​​cell 101 , at least two sliced ​​cell 101 are formed by cutting the same whole solar cell, and the sliced ​​cell 101 has a cutting surface 111 .

[0080] The solar cell further includes: a first passivation layer 102 , the first passivation layer 102 at least partially covers the cut surface 111 of the sliced ​​cell 101 .

[0081] The solar cell further includes: a second passivation layer 103 , which covers at least one side of the first passivation layer 102 away from the sliced ​​solar cell 101 .

[0082] The solar cell further includes: a third passivation layer 104 , and the third passivation layer 104 at least covers a surface of the second passivation layer 103 that is away from the first passivation layer 102 .

[0083] The solar cell also includes: a fourth passivation layer 105, which covers at least one side surface of the third passivation layer 104 away from the second passivation layer 103, wherein the material of the first passivation layer 102 is semiconductor oxide, the material of the second passivation layer 103 is metal semiconductor oxide, the material of the third passivation layer 104 and the fourth passivation layer 105 is metal oxide, the density of the third passivation layer 104 is greater than that of the fourth passivation layer 105, and the thickness of the third passivation layer 104 is less than that of the fourth passivation layer 105.

[0084] The embodiment of the present disclosure can improve the passivation effect on the cut surface 111 of the sliced ​​battery cell 101 by setting a stack of the first passivation layer 102, the second passivation layer 103, the third passivation layer 104 and the fourth passivation layer 105, thereby reducing the recombination center of the cut surface 111, and for the third passivation layer 104 and the fourth passivation layer 105, setting the material of the third passivation layer 104 and the fourth passivation layer 105 to be metal oxide can utilize metal elements to make the third passivation layer 104 and the fourth passivation layer 105 themselves have a high density of fixed charges, and the high density of fixed charges can generate a large electric field, thereby performing good field effect passivation on the cut surface 111, for example, A larger energy band bending is generated between the third passivation layer 104 and the cutting surface 111, which hinders the minority carriers from migrating to the cutting surface 111 and reduces the concentration of minority carriers at the cutting surface 111, thereby helping to reduce the probability of recombination of majority carriers and minority carriers at the cutting surface 111. Moreover, by setting the processes of the third passivation layer 104 and the fourth passivation layer 105 to be different, the density of the fourth passivation layer 105 is made smaller than the density of the third passivation layer 104, thereby reducing the process difficulty of the fourth passivation layer 105 and increasing the formation speed of the fourth passivation layer 105, so as to take into account the passivation performance of the third passivation layer 104 and the fourth passivation layer 105 while taking into account the production efficiency of the battery cell.

[0085] Taking the whole solar cell as a TOPCon cell as an example, the formed sliced ​​cell 101 may have a substrate 110, a front emitter 120, a front passivation layer 130, a front electrode 140, a back oxide layer 150, a back doped conductive layer 160, a back passivation layer 170 and a back electrode 180. The whole solar cell may also be other types of cells, and the formed sliced ​​cell 101 also has the basic characteristics of other types of cells.

[0086] In some embodiments, the metal element of the second passivation layer 103 is the same as the metal element of the third passivation layer 104, and the doping concentration of the metal element of the second passivation layer 103 is less than the doping concentration of the metal element of the third passivation layer 104. In this way, on the one hand, the formation process of the second passivation layer 103 can be facilitated, and the metal element of the third passivation layer 104 can be controlled to diffuse into the second passivation layer 103 when the third passivation layer 104 is formed. On the other hand, the lattice difference of the contact surface between the second passivation layer 103 and the third passivation layer 104 can be reduced, and the doping concentration of the metal element of the second passivation layer 103 is set to be less than the doping concentration of the metal element of the third passivation layer 104, so that in the process from the first passivation layer 102 to the third passivation layer 104, the metal doping elements in different passivation layers show a gradual change, which is conducive to improving the performance stability of the second passivation layer 103 and improving the overall stability of the first passivation layer 102 to the third passivation layer 104, and avoiding the performance mutation caused by the sudden change of the metal element content.

[0087] In some embodiments, in the direction from the second passivation layer 103 to the third passivation layer 104 , the doping concentration of the metal element in the second passivation layer 103 gradually increases, and the proportion of the doping element may increase from 2% to 50%.

[0088] In some embodiments, the thickness of the third passivation layer 104 is 5 to 15 nm, for example, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 12 nm or 14 nm, etc. It can be understood that for the third passivation layer 104, the thicker the third passivation layer 104 is, the better the passivation effect brought by the third passivation layer 104 is. Moreover, due to the high density of the third passivation layer 104, the thicker the third passivation layer 104 is, the higher its stability is. However, due to the high density of the third passivation layer 104, the time required for the formation process of the third passivation layer 104 is longer. By controlling the thickness of the third passivation layer 104 to 5 to 15 nm, the passivation effect of the third passivation layer 104 can be considered while taking into account the production time of the battery cell.

[0089] In some embodiments, the thickness of the fourth passivation layer 105 is 20-100 nm, for example, 30 nm, 40 nm, 50 nm, 55 nm, 60 nm, 70 nm, 80 nm or 90 nm, etc. For the fourth passivation layer 105, the fourth passivation layer 105 needs to have a certain thickness to prevent the fourth passivation layer 105 from failing due to adsorption of water vapor or particles in the air, thereby improving the reliability of the fourth passivation layer 105. Similarly, the thicker the fourth passivation layer 105, the longer it takes to form the fourth passivation layer 105, which will reduce the production capacity of the battery cell. Therefore, by setting the thickness of the fourth passivation layer 105 to 20-100 nm, the reliability of the fourth passivation layer 105 can be considered while taking into account the production time of the battery cell.

[0090] In some embodiments, the thickness of the fourth passivation layer 105 is 35-60 nm, for example, 40 nm, 44 nm, 50 nm, 53 nm, 57 nm or 59 nm, etc. For the fourth passivation layer 105, the fourth passivation layer 105 covers the outermost side of the cut surface 111 of the sliced ​​battery cell 101. If the thickness of the fourth passivation layer 105 is too thick, the contact area between the fourth passivation layer 105 and the outside world will be larger, and the area for adsorbing water vapor and particles will be larger. In addition, the quality caused by the thickness and the failure caused by the adsorption of impurities will cause the fourth passivation layer 105 to fall off. Therefore, setting the thickness of the fourth passivation layer 105 to 35-60 nm can improve the reliability of the fourth passivation layer 105 while considering the passivation effect of the fourth passivation layer 105.

[0091] In some embodiments, the sliced ​​battery cell 101 includes a front side and a back side opposite to each other, and the angle between the cutting surface 111 and the front side or the back side is an acute angle. It can be understood that, taking the example of cutting a whole solar cell into two sliced ​​cells 101, the two sliced ​​cells 101 have opposite front sides. If the angle between the front side of one sliced ​​cell 101 and the cutting surface 111 is an acute angle, then the angle between the front side of the other corresponding sliced ​​cell 101 and the cutting surface 111 is an obtuse angle. Compared with cutting along the thickness direction of the whole cell, setting the angle between the cutting surface 111 and the front side or the back side to an acute angle can reduce the atomic arrangement density on the cutting surface 111, reduce the covalent interface density, and make the connection between adjacent atoms on the cutting surface 111 less reliable, which is more conducive to promoting the bonding of the multi-layer passivation layer with the dangling bonds on the cutting surface 111, and can further improve the overall passivation ability of the first passivation layer 102, the second passivation layer 103, the third passivation layer 104 and the fourth passivation layer 105, further reduce the probability of carrier recombination on the cutting surface 111, improve the carrier lifetime, and further improve the photoelectric conversion efficiency of the solar cell.

[0092] In some embodiments, the acute angle is 45° to 80°, for example, 50°, 55°, 60°, 68° or 73°, etc. It is understandable that the smaller the acute angle, the more conducive it is to reducing the probability of carrier recombination on the cut surface 111, but too small an acute angle will also bring reliability problems. When the acute angle is less than 45°, the tip formed by the cut surface 111 and the front or back surface will be easily damaged, which will cause abnormality of the solar cell. Therefore, by setting the acute angle to 45° to 80°, the probability of carrier recombination on the cut surface 111 can be further reduced, while reducing the probability of damage to the solar cell.

[0093] In some embodiments, the acute angle is 45° to 55°, such as 47°, 48°, 49°, 50°, 51°, 52°, 53° or 54°. When the acute angle is 45° to 55°, for the cutting surface 111, the crystal plane on the cutting surface 111 is <111> The crystal plane will make the density of silicon atoms the sparsest at this angle, taking the substrate material as silicon as an example, which is more conducive to promoting the bonding of the multi-layer passivation layer with the dangling bonds on the cutting surface 111, and further improving the overall passivation ability of the first passivation layer 102, the second passivation layer 103, the third passivation layer 104 and the fourth passivation layer 105.

[0094] Another embodiment of the present disclosure further provides a photovoltaic module, which is used to convert received light energy into electrical energy. The following will describe in detail a method for preparing a solar cell provided by another embodiment of the present disclosure in conjunction with the accompanying drawings. Figure 6 A schematic diagram of a partial three-dimensional structure of a photovoltaic assembly provided by another embodiment of the present disclosure; Figure 7 for Figure 6 A schematic diagram of a cross-sectional structure along the cross-sectional direction MM1. It should be noted that the parts identical or corresponding to the above-mentioned embodiments are not described in detail here.

[0095] refer to Figure 6 and Figure 7 The photovoltaic module includes: a battery string, which is formed by connecting multiple solar cells formed by the manufacturing method described in all or part of the above embodiments, or is formed by connecting multiple solar cells described in all or part of the above embodiments; a packaging film 41, which is used to cover the surface of the battery string; a cover plate 42, which is used to cover the surface of the packaging film 41 away from the battery string.

[0096] It is worth noting that the solar cells 40 are electrically connected to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel. Since the solar cell 40 includes a sliced ​​cell 101, and the sliced ​​cell 101 is formed by dividing the whole solar cell, the power loss of the photovoltaic module can be improved by the current drop of the sliced ​​cell 101, so as to improve the photoelectric conversion efficiency of the photovoltaic module.

[0097] In some embodiments, reference Figure 7 , multiple battery strings can be electrically connected through the conductive tape 402. Figure 7 Only one positional relationship between solar cells is illustrated, that is, the arrangement direction of the electrodes with the same polarity of the cells is the same, or the electrodes with positive polarity of each cell are arranged toward the same side, so that the conductive tape connects different sides of two adjacent cells. In some embodiments, the cells can also be arranged in the order of electrodes with different polarities facing the same side, that is, the electrodes of multiple adjacent cells are arranged in the order of the first polarity, the second polarity, and the first polarity, and the conductive tape connects two adjacent cells on the same side.

[0098] In some embodiments, no intervals are set between the battery cells, that is, the battery cells overlap each other.

[0099] In some embodiments, the encapsulation film 41 includes a first encapsulation layer and a second encapsulation layer, the first encapsulation layer covers one of the front side or the back side of the solar cell 40, and the second encapsulation layer covers the other of the front side or the back side of the solar cell 40. Specifically, at least one of the first encapsulation layer or the second encapsulation layer can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene co-elastomer (POE) film or a polyethylene terephthalate (PET) film.

[0100] In some cases, there is a boundary between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0101] In some embodiments, the cover plate 42 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulation film 41 may be a concave-convex surface, thereby increasing the utilization rate of the incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0102] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for implementing the present disclosure, and in practical applications, various changes can be made to them in form and detail without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure, so the protection scope of the embodiments of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A method for manufacturing a battery cell, characterized in that: include: Providing initial battery cells; Cutting the initial battery cell to form a sliced ​​battery cell having at least one cutting surface; forming a first passivation layer, wherein the first passivation layer at least covers a portion of a cutting surface of the sliced ​​solar cell; forming a second passivation layer, wherein the second passivation layer at least covers a surface of a side of the first passivation layer away from the sliced ​​solar cell; forming a third passivation layer, wherein the third passivation layer at least covers a surface of the second passivation layer on a side away from the first passivation layer; forming a fourth passivation layer, wherein the fourth passivation layer at least covers a surface of the third passivation layer away from the second passivation layer; Among them, the material of the first passivation layer is semiconductor oxide, the material of the second passivation layer is metal semiconductor oxide, the materials of the third passivation layer and the fourth passivation layer are metal oxide, and the third passivation layer and the fourth passivation layer adopt different processes so that the density of the third passivation layer is greater than that of the fourth passivation layer, and the thickness of the third passivation layer is less than that of the fourth passivation layer.

2. The method according to claim 1, characterized in that: The process for forming the third passivation layer includes: forming the third passivation layer by an atomic layer deposition process, and the process parameters for forming the third passivation layer include: process temperature: 150-350°C, and sequentially introducing a gas source containing metal elements, nitrogen, water vapor / nitrogen and nitrogen, each gas flow rate is 500-3000sccm, the time for each gas introduction is 3-15s, and the gas is introduced 10-600 times.

3. The method according to claim 2, characterized in that: The method for forming the second passivation layer includes: in the process of forming the third passivation layer, controlling the diffusion of metal elements of the third passivation layer into a portion of the first passivation layer to convert a portion of the first passivation layer into the second passivation layer.

4. The method according to claim 1, characterized in that: The process for forming the fourth passivation layer includes: forming the fourth passivation layer by chemical vapor deposition, and the process parameters for forming the fourth passivation layer include: process temperature: 150~600℃, while introducing a gas source containing a metal element, a gas source containing an oxygen element and nitrogen, each gas flow rate is 300~2000sccm, and plasma is excited.

5. The method according to claim 1, characterized in that: The sliced ​​battery cell includes a substrate, and the method for forming the first passivation layer includes: oxidizing the cut surface of the sliced ​​battery cell to convert part of the substrate of the sliced ​​battery cell into the first passivation layer, and the process parameters for forming the first passivation layer include: process temperature: 100-150°C, the gas flow rate of the water vapor is 1000-2000sccm, and the duration is 5-60s.

6. The method according to claim 1, characterized in that: The process parameters for cutting the initial battery sheet include: laser power of 80-100w, water flow of 1-5ml, and a cutting angle of 45-90°.

7. A solar cell, characterized in that: include: Sliced ​​solar cells, at least two of which are formed by cutting the same whole solar cell. The sliced ​​battery sheet has a cutting surface; A first passivation layer, wherein the first passivation layer at least covers a portion of a cutting surface of the sliced ​​solar cell; A second passivation layer, the second passivation layer at least covers a surface of a side of the first passivation layer away from the sliced ​​solar cell; a third passivation layer, the third passivation layer at least covering a surface of the second passivation layer on a side away from the first passivation layer; A fourth passivation layer, the fourth passivation layer at least covers a surface of the third passivation layer on one side away from the second passivation layer; wherein the material of the first passivation layer is a semiconductor oxide, the material of the second passivation layer is a metal semiconductor oxide, the materials of the third passivation layer and the fourth passivation layer are metal oxides, the density of the third passivation layer is greater than that of the fourth passivation layer, and the thickness of the third passivation layer is less than that of the fourth passivation layer.

8. The solar cell according to claim 7, characterized in that: The metal element of the second passivation layer is the same as the metal element of the third passivation layer, and the doping concentration of the metal element of the second passivation layer is lower than the doping concentration of the metal element of the third passivation layer.

9. The solar cell according to claim 7, characterized in that: The thickness of the third passivation layer is 5-15 nm, and / or the thickness of the fourth passivation layer is 20-100 nm.

10. The solar cell according to claim 7, characterized in that: The sliced ​​battery sheet includes a front side and a back side opposite to each other, and the angle between the cutting surface and the front side or the back side is an acute angle.

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