Solar cell manufacturing method and solar cell

Abstract

The present application relates to the technical field of solar cell technology and discloses a method for preparing a solar cell and a solar cell. The method for preparing a solar cell of the present application comprises: providing an initial sliced ​​cell having a cross section; performing an oxidation treatment on the cross section to form an oxide layer; forming a hydrogen-containing passivation layer on a surface of the oxide layer away from the cross section; performing a hydrogen passivation activation treatment on a surface of the hydrogen-containing passivation layer away from the oxide layer to release hydrogen ions in the hydrogen-containing passivation layer to the cross section, thereby forming a passivated sliced ​​cell. By performing an oxidation treatment on the cross section of the initial sliced ​​cell to form an oxide layer, dangling bonds on the cross section are saturated to improve the passivation effect; performing a hydrogen passivation activation treatment on a surface of the hydrogen-containing passivation layer away from the oxide layer to release hydrogen ions in the hydrogen-containing passivation layer to the cross section, thereby passivating the damaged area of ​​the cross section and repairing internal defects of the cross section, thereby improving the performance of the sliced ​​cell.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a method for preparing a solar cell and a solar cell. Background Art

[0002] Currently, the technology for producing half-cell or multi-cell cells has the advantages of reducing the internal resistance of solar cells and improving their conversion efficiency, and is widely used in the production of solar cells. In the process of producing modules using half-cell or multi-cell cells, the conventional process involves dividing the cell into multiple slices using laser scribing technology and then depositing a hybrid passivation layer on the cross-section using ALD (Atomic Layer Deposition) technology.

[0003] However, the passivation effect of the existing segmented cell cross-section is poor, resulting in poor performance of the cell. Summary of the Invention

[0004] The purpose of the embodiments of the present application is to provide a method for preparing a solar cell and a solar cell, thereby improving the passivation effect of the cross section of the segmented solar cell and improving the performance of the segmented solar cell.

[0005] To solve the above technical problems, an embodiment of the present application provides a method for preparing a solar cell, comprising: providing an initial sliced ​​cell having a cross-section; performing an oxidation treatment on the cross-section to form an oxide layer; forming a hydrogen-containing passivation layer on a surface of the oxide layer away from the cross-section; performing a hydrogen passivation activation treatment on a surface of the hydrogen-containing passivation layer away from the oxide layer to release hydrogen ions in the hydrogen-containing passivation layer to the cross-section to form a passivated sliced ​​cell.

[0006] An embodiment of the present application further provides a solar cell, comprising: the passivated segmented cell sheet prepared by the above-mentioned solar cell preparation method.

[0007] In some embodiments, the oxidation treatment of the cross section to form an oxide layer includes: performing a first preheating treatment on the cross section to form an initial oxide layer on the cross section; and performing a second oxidation treatment on the initial oxide layer to oxidize the initial oxide layer to form the oxide layer.

[0008] In some embodiments, the second oxidation treatment is: performing a first laser treatment on the initial oxide layer in an oxygen-rich environment.

[0009] In some embodiments, the hydrogen passivation activation treatment is a second laser treatment; the energy of the second laser treatment is lower than the energy of the first laser treatment.

[0010] In some embodiments, before performing hydrogen passivation activation treatment on the surface of the hydrogen-containing passivation layer away from the oxide layer, the method includes: performing a second preheat treatment on the surface of the hydrogen-containing passivation layer away from the oxide layer; the temperature of the second preheat treatment is lower than the temperature of the first preheat treatment.

[0011] In some embodiments, the thickness of the hydrogen-containing passivation layer is greater than the thickness of the oxide layer; the thickness of the oxide layer is 5 nm to 10 nm, and the thickness of the hydrogen-containing passivation layer is 5 nm to 50 nm.

[0012] In some embodiments, the power of the first laser treatment is 150W to 300W, and the temperature of the first laser treatment is 500°C to 1000°C; the power of the second laser treatment is 80W to 150W, and the temperature of the second laser treatment is 300°C to 750°C.

[0013] In some embodiments, the temperature of the first preheat treatment is 100°C to 300°C; the temperature of the second preheat treatment is 50°C to 100°C.

[0014] In some embodiments, the duration of the first preheating treatment is greater than that of the second oxidation treatment; the duration of the first preheating treatment is 600s to 900s; and the duration of the second oxidation treatment is 100s to 500s.

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

[0016] In the embodiment of the present application, an oxide layer is formed by oxidizing the cross section of the initial sliced ​​battery cell to saturate the dangling bonds on the cross section and improve the passivation effect; after depositing a hydrogen-containing passivation layer on the oxide layer, a hydrogen passivation activation treatment is performed on the surface of the hydrogen-containing passivation layer away from the oxide layer to release hydrogen ions in the hydrogen-containing passivation layer to the cross section, so as to passivate the damaged area of ​​the cross section and repair the internal defects of the cross section to form a passivated sliced ​​battery cell, thereby improving the passivation effect of the sliced ​​battery cell and thus improving the performance of the sliced ​​battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0018] Figure 1 This is a schematic diagram of the structure of a micron-scale crack at the cross section of a split cell in the related art;

[0019] Figure 2 Schematic diagram of the structure of a hybrid passivation layer film in the related art;

[0020] Figure 3 A schematic diagram of bisecting a cell;

[0021] Figure 4 A schematic diagram of cutting a battery cell into four equal parts;

[0022] Figure 5 This is a schematic structural diagram of the solar cell after the first preheating treatment in the method for preparing the solar cell provided in this embodiment;

[0023] Figure 6 This is a schematic diagram of the structure of the solar cell after the second oxidation treatment in the method for preparing the solar cell provided in this embodiment;

[0024] Figure 7 This is a schematic diagram of the structure after the hydrogen-containing passivation layer is formed in the solar cell preparation method provided in this embodiment;

[0025] Figure 8 This is a schematic diagram of the structure of the solar cell after hydrogen passivation activation treatment in the method for preparing the solar cell provided in this embodiment;

[0026] Figure 9 Schematic diagram of the structure of the hydrogen-containing passivation layer provided in this embodiment. DETAILED DESCRIPTION

[0027] As can be seen from the background art, the passivation effect of the cross section of the existing segmented solar cells is poor, resulting in poor performance of the solar cells.

[0028] After analysis and research, it was found that in the currently known preparation process of split cells, the conventional process is to divide the cell into two symmetrical halves or multiple slices by laser scribing, and then deposit a mixed passivation layer film on the cross section for passivation, and then deliver it to the component packaging and welding. However, the current laser slicing process will produce a heat-affected zone with a depth of microns at the cross section of the split cell and a mechanical damage zone of the split cell, such as Figure 1 As shown in the figure, it is a schematic diagram of the structure of micron-scale cracks at the cross section of a split cell in the related art. Figure 1 The micron-scale crack area shown will expose a large number of dangling bonds to form recombination centers. The internal defects of the damaged area are serious and need to be repaired by certain means to obtain higher component power. In related technologies, ALD technology is used to deposit a hybrid passivation layer, such as Figure 2 The figure shows the structure of the hybrid passivation layer film in the related art. Conventional ALD technology is usually used to passivate relatively flat surface structures. However, due to the excessive surface roughness and severe damage in the cross-sectional structure, it is difficult to passivate the deep damaged area by relying solely on the ALD low-temperature process. Moreover, after the low-temperature deposition of the film, a large number of hydrogen ions are concentrated in the film, which does not play a significant role in repairing the cross-sectional damaged area. Therefore, Figure 2The hybrid passivation layer film deposited at low temperature has poor density and poor passivation.

[0029] In order to improve the passivation effect of the cross-section of the sliced ​​cell and improve the performance of the cell, an embodiment of the present application provides a method for preparing a solar cell, wherein the cross-section of the initial sliced ​​cell is oxidized to form an oxide layer to saturate the dangling bonds on the cross-section and improve the passivation effect; after depositing a hydrogen-containing passivation layer on the oxide layer, the surface of the hydrogen-containing passivation layer away from the oxide layer is subjected to a hydrogen passivation activation treatment to release hydrogen ions in the hydrogen-containing passivation layer to the cross-section, so as to passivate the damaged area of ​​the cross-section and repair the internal defects of the cross-section to form a passivated sliced ​​cell, thereby improving the passivation effect of the sliced ​​cell and thus improving the performance of the sliced ​​cell.

[0030] In the description of the embodiments of the present disclosure, technical terms such as "first" and "second" are used solely to distinguish between different objects and should not be understood to indicate or imply relative importance or to implicitly specify the quantity, specific order, or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, "plurality" means more than two, unless otherwise specifically defined.

[0031] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0032] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of an association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can represent the following three situations: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this document generally indicates that the associated objects are in an "or" relationship.

[0033] 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).

[0034] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0035] In the description of the embodiments of the present disclosure, unless otherwise expressly specified or limited, technical terms such as "installed," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and can refer to internal connectivity between two components or interaction between two components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present disclosure based on specific circumstances.

[0036] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are exaggerated for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) as being 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. Conversely, when describing a component as being on the surface of another component, or when describing a component as being 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 portion of the edge of the entire surface.

[0037] In the description of the embodiments of the present disclosure, when a component is referred to as "including" 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 being "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 can be present between them. In addition, when a component such as a layer, film, region, or plate is "directly 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 between them.

[0038] Figures 3 to 8 This is a schematic structural diagram corresponding to each step of a solar cell manufacturing method provided in this embodiment.

[0039] refer to Figure 3 、 Figure 4 , Figure 3 A schematic diagram of bisecting a cell. Figure 4 This is a schematic diagram of cutting a cell into four equal parts. This embodiment provides an initially sliced ​​cell 100 having a cross section 101 .

[0040] The initial cell 100 of this embodiment is formed by laser scribing, which uses a high-power density laser beam to irradiate the battery electrode material, causing it to quickly heat up to melting, vaporizing or burning, thereby cutting the cell to form the initial cell 100. In other embodiments, the initial cell 100 can also be obtained by other cutting processes, such as blade cutting, stamping cutting, diamond wire cutting, etc., as long as there is a cross section 101 of the initial cell 100 as shown in FIG. Figure 1 The micron-sized cracks shown are sufficient.

[0041] A cell consists of a substrate material, a PN junction, a front surface electrode, a rear surface electrode, a passivation layer, and an anti-reflection layer. The substrate material is the main support for the cell and the generation layer of photogenerated carriers. The substrate material is single-crystal silicon or polycrystalline silicon. The PN junction is composed of P-type and N-type regions and is used to separate photogenerated carriers. The front surface electrode is used to collect photogenerated carriers and transmit current and is generally printed from silver paste. The rear surface electrode is used to collect current and provide an electric field and is generally made of aluminum or other metal materials. The passivation layer is a thin film coated on the front and rear surfaces of the cell to reduce surface recombination and improve cell efficiency. The anti-reflection layer is used to reduce light reflection and improve light absorption efficiency and is generally made of materials such as silicon nitride SiNx.

[0042] During the photovoltaic cell production process, cell slicing occurs in the latter stages of production, after the basic cell manufacturing process, which includes texturing, diffusion, coating, screen printing, and sintering. Before slicing, it's necessary to understand the user's requirements for photovoltaic modules. Cell slicing is then performed based on these requirements to accommodate modules of varying sizes. After slicing, the slicing process is then assembled to form photovoltaic modules.

[0043] After the cell is sliced, the initial sliced ​​cell 100 of this embodiment is formed. The initial sliced ​​cell 100 of this embodiment can be a half-cell cell or a multi-cell cell, which is set according to actual needs. In the case where the initial sliced ​​cell 100 is a half-cell cell, only one side of the initial sliced ​​cell 100 has a cross section, such as Figure 3As shown, it is a schematic diagram of bisecting a cell, where the cell is cut into two symmetrical pieces, and the initial cell 100 has a cross section 101 on only one side; in the case where the initial cell 100 can be a half cell or a multi-cell cell, multiple sides of the initial cell 100 have cross sections, such as Figure 4 FIG. 1 is a schematic diagram of a cell being cut into four equal pieces. The cell is cut into four pieces, and the initial cell 100 has two adjacent cross sections 101. The initial cell 100 of this embodiment can also be a six-piece cell, an eight-piece cell, etc. The specific number of cuts is set according to actual needs.

[0044] refer to Figure 3 In this embodiment, the initially sliced ​​cell 100 is taken as a half-cell cell for illustration, that is, only one side of the initially sliced ​​cell 100 (i.e. Figure 3 There is a cross section 101 on the right side of the figure. In practical applications, when the initial split battery cell 100 is a multi-split battery cell, the other sides of the initial split battery cell 100 (i.e. Figure 3 The left side, upper surface, and lower surface in the figure may also have a cut cross-section 101.

[0045] The initial sliced ​​cell 100 of this embodiment is still composed of a base material, a PN junction, a front surface electrode, a rear surface electrode, a passivation layer, and an anti-reflection layer. After cutting, the initial sliced ​​cell 100 can reduce the single string current, reduce current loss, and at the same time improve the mechanical load resistance of the formed photovoltaic module.

[0046] The initial cell 100 of this embodiment has the following Figure 1 The micron-scale cracks shown here will expose a large number of Si-SiO2 dangling bonds to form composite centers, resulting in excessive roughness of the cross section 101 and a more serious damage area. Figure 2 The hybrid passivation layer deposited in the related art cannot play a significant role in repairing the damaged area of ​​the cross section 101, resulting in poor density of the hybrid passivation layer film and poor passivation, resulting in poor passivation effect of the cross section of the initial sliced ​​battery cell 100 after dicing.

[0047] In order to improve the passivation effect of the cross section of the initial sliced ​​cell 100, refer to Figure 5 、 Figure 6 , the cross section 101 is oxidized to form an oxide layer 103 .

[0048] In this embodiment, an oxidation treatment is performed on the cross section of the initial split cell 100 to form an oxide layer 103, which effectively passivates the surface state at the cross section 101 of the initial split cell 100, reduces the recombination of some carriers, and improves the passivation effect of the cross section 101 of the initial split cell 100; at the same time, the oxide layer 103 can block impurity atoms from diffusing into the silicon substrate of the initial split cell 100, and prevents atoms other than hydrogen ions from diffusing into the silicon substrate during the subsequent hydrogen passivation activation treatment, thereby maintaining a good passivation effect of the cross section 101 of the initial split cell 100.

[0049] The oxide layer 103 of this embodiment is formed by oxidizing part of the silicon substrate at the cross section 101 to form silicon oxide. After the cross section 101 is oxidized, a dense oxide layer 103, i.e., silicon oxide, is generated on the cross section 101 to fully saturate the Si-SiO2 interface dangling bonds, thereby improving the passivation effect of the oxide layer 103.

[0050] Since the higher the density of the oxide layer 103 , the better the passivation effect of the cross section 101 of the initially sliced ​​cell 100 , in order to further improve the passivation effect of the cross section 101 , this embodiment performs two oxidation treatments, namely a first preheating treatment and a second oxidation treatment, thereby improving the density of the oxide layer 103 .

[0051] refer to Figure 5 , Figure 5 This is a schematic structural diagram of a solar cell after the first preheating treatment in the method for preparing the solar cell provided in this embodiment. In this embodiment, the first preheating treatment is performed on the cross section 101 to form an initial oxide layer 102 on the cross section 101 .

[0052] In order to reduce the actual power of the subsequent first laser treatment and reduce the negative effect of thermal damage caused by the first laser treatment on the cross section 101, this embodiment performs a first preheat treatment on the cross section 101 before the first laser treatment to form an initial oxide layer 102 on the cross section. Therefore, before the first laser treatment, the cross section 101 is first subjected to the first preheat treatment, which not only forms the initial oxide layer 102, which is equivalent to pre-forming a partial oxide layer 103, reducing the time for forming the oxide layer 103 in the subsequent first laser treatment and improving the efficiency of the first laser treatment, but also preheats the temperature of the cross section 101 to the first preset temperature, reducing the actual power of the subsequent first laser treatment, thereby reducing the negative effect of thermal damage caused by the first laser treatment on the cross section 101, and thus improving the passivation effect of the formed oxide layer 103.

[0053] Before performing the first preheat treatment, this embodiment places a cross section 101 of the initial split cell 100 in a fixture and exposes the cross section 101 to an ozone environment for the first preheat treatment. The ozone concentration is within a range of 800 ppm to 1200 ppm, for example, 800 ppm, 900 ppm, 1000 ppm, 1100 ppm, or 1200 ppm. By setting the ozone concentration within this range, this embodiment provides a rich oxygen environment for the preheat oxidation of the cross section 101, thereby improving the efficiency of the first preheat treatment and ensuring that the thickness of the generated initial oxide layer 102 is uniform and dense. Furthermore, this prevents excessive ozone concentration from causing over-oxidation of the cross section 101, thereby reducing the probability of defects in the cross section 101 due to over-oxidation. This improves the performance of the resulting split cell, such as reducing recombination, improving carrier transport, increasing the threshold voltage and fill, and increasing power.

[0054] In addition, ozone, as a strong oxidant, can decompose various pollutants in a short period of time, so that the cross section 101 reaches a higher cleanliness level. In this embodiment, the ozone concentration is set within this range, which can also effectively remove impurities and organic pollutants on the cross section 101 and avoid damage to the cross section 101.

[0055] In some embodiments, the preheating temperature of the first preheating treatment is 100° C. to 300° C., for example, 100° C., 150° C., 200° C., 250° C., or 300° C. By setting the temperature of the first preheating treatment within this range, on the one hand, the temperature of the cross section 101 can be quickly preheated to the first preset temperature, reducing the actual power of the subsequent first laser treatment and preventing damage to the cross section 101 due to excessive power of the first laser treatment. On the other hand, excessively high preheating temperatures can be avoided, which can lead to rapid temperature changes in the cross section 101. This ensures uniform temperature distribution in the cross section 101, reduces performance differences caused by local overheating or overcooling, provides a cross section 101 with uniform temperature for the subsequent first laser treatment, improves the density of the generated oxide layer 103, and enhances the passivation effect of the oxide layer 103.

[0056] In some embodiments, the duration of the first preheating treatment is 600s to 900s, for example, 600s, 650s, 700s, 750s, 800s, 850s, or 900s. By setting the duration of the first preheating treatment within this range, on the one hand, the temperature of the cross section 101 after the first preheating treatment is ensured to be uniform, thereby improving the density of the oxide layer 103 generated by the first laser treatment. On the other hand, the problem of performance degradation of the resulting sliced ​​cell due to the first preheating treatment being too long is avoided, thereby improving the performance of the sliced ​​cell.

[0057] In this embodiment, after the cross section 101 of the initial split cell 100 is subjected to a first preheat treatment, an initial oxide layer 102 is formed on the cross section 101, which is equivalent to pre-forming a partial oxide layer 103, thereby reducing the time required for the subsequent first laser treatment to form the oxide layer 103. In some embodiments, the thickness of the initial oxide layer 102 is 1 nm to 3 nm, for example, 1 nm, 2 nm, or 3 nm. By setting the thickness of the initial oxide layer 102 within this range, on the one hand, a partial oxide layer 103 can be pre-formed, reducing the time required for the subsequent first laser treatment to form the oxide layer 103, thereby improving the efficiency of the first laser treatment. On the other hand, the problem of poor passivation of the initial oxide layer 102 due to the thickness of the initial oxide layer 102 is avoided, which makes it impossible for the subsequent first laser treatment to effectively perform deep oxidation, thereby improving the passivation effect of the subsequently formed oxide layer 103.

[0058] refer to Figure 6 , Figure 6 This is a schematic structural diagram of the solar cell after the second oxidation treatment in the method for preparing the solar cell provided in this embodiment. In this embodiment, the second oxidation treatment is performed on the initial oxide layer 102 , and the initial oxide layer 102 is oxidized to form an oxide layer 103 .

[0059] In this embodiment, after the initial oxide layer 102 is formed on the cross section 101, the initial oxide layer 102 is subjected to a second oxidation treatment, so that the thickness and density of the initial oxide layer 102 are increased to form an oxide layer 103, thereby forming an oxide layer 103 with uniform thickness and density. The second oxidation treatment generates a denser oxide layer 103 relative to the first preheat treatment, so as to fully saturate the dangling bonds at the Si-SiO2 interface in the silicon substrate, thereby improving the performance of the finally formed sliced ​​cell, including reducing recombination, improving carrier transport, increasing the opening voltage and filling, and increasing power.

[0060] In some embodiments, the second oxidation treatment is: performing a first laser treatment on the initial oxide layer 102 in an oxygen-rich environment. The oxygen-rich environment is an environment containing an oxygen-containing liquid, so that the initial oxide layer 102 can be further oxidized to obtain an oxide layer with a higher density. The first laser treatment of this embodiment can be achieved by using a red or green continuous wave laser, or by a picosecond or nanosecond laser. The laser irradiates the cross section 101 perpendicular to the cross section, and the spot shape is circular or square. The circular diameter or square size ranges from 1 mm to 2 mm. At the same time, hydrogen peroxide is sprayed on the cross section 101 to provide an oxygen-rich environment on the high-temperature cross section 101. The purity of the hydrogen peroxide is 30%-40%. In other embodiments, other oxygen-containing liquids can also be sprayed on the cross section, such as ozone water.

[0061] In some embodiments, the power of the first laser treatment is 150 W to 300 W, for example, 150 W, 200 W, 250 W, or 300 W. Because the cross section 101 is subjected to a first preheating treatment before the first laser treatment so that the temperature of the cross section 101 reaches a first preset temperature and the temperature distribution of the cross section 101 is uniform, the actual power of the first laser treatment can be set relatively low. Even if the power of the first laser treatment is set within this range, a uniform and dense oxide layer 103 can be formed on the cross section 101. At the same time, when the power of the first laser treatment is set within this range, the negative effects of thermal damage caused by the laser on the cross section 101 can be reduced, thereby improving the performance of the resulting split solar cell.

[0062] In some embodiments, during the first laser treatment process, the laser scanning speed is 1000 mm / s to 30,000 mm / s, for example, 1000 mm / s, 1500 mm / s, 2000 mm / s, 2500 mm / s, and 3000 mm / s. By setting the laser scanning speed within this range, on the one hand, the problem of uneven thickness of the formed oxide layer 103 due to excessively fast scanning speeds can be avoided, and on the other hand, the problem of excessive thermal damage to the cross section 101 due to excessively slow scanning speeds can be avoided, thereby improving the passivation effect of the formed oxide layer 103.

[0063] In some embodiments, the temperature of the first laser treatment is 500° C. to 1000° C., for example, 500° C., 600° C., 700° C., 800° C., 900° C., or 1000° C. By setting the temperature of the first laser treatment within this range, on the one hand, the density of the generated oxide layer 103 can be improved, and the passivation effect of the oxide layer 103 can be improved. On the other hand, heat accumulation can be reduced, avoiding unnecessary thermal damage to the sliced ​​solar cell caused by the first laser treatment temperature being too high, thereby improving the performance of the ultimately formed sliced ​​solar cell.

[0064] In some embodiments, the duration of the first preheating treatment is longer than the duration of the second oxidation treatment. This arrangement can, on the one hand, make the temperature of the cross section 101 obtained by the first preheating treatment more uniform, and can also improve the uniformity and density of the initial oxide layer 102. On the other hand, since the first preheating treatment has already preheated the cross section 101, even if the duration of the second oxidation treatment is set to be shorter, a uniform and dense oxide layer 103 can be generated. At the same time, the problem of thermal damage caused by the excessive temperature of the first laser treatment can also be avoided, thereby improving the performance of the sliced ​​solar cell.

[0065] In some embodiments, the duration of the first laser treatment is 100s to 500s, for example, 100s, 200s, 300s, 400s, or 500s. By setting the duration of the first laser treatment within this range, on the one hand, the thickness of the formed oxide layer 103 can be ensured to be uniform and compact, and on the other hand, the problem of thermal damage to the cross section 101 caused by an excessively long duration of the first laser treatment can be avoided, thereby improving the performance of the resulting split cell.

[0066] In some embodiments, the thickness of the oxide layer 103 is 5 nm to 10 nm, for example, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, and 10 nm. By setting the thickness of the oxide layer 103 within this range, on the one hand, a denser oxide layer 103 can be formed, the passivation effect of the oxide layer 103 can be improved, and the dangling bonds at the Si-SiO2 interface in the silicon substrate can be fully saturated. On the other hand, the oxide layer 103 can be prevented from being too thick, which can cause the hydrogen ions of the subsequent hydrogen passivation layer to be unable to effectively diffuse to the cross section 101, thereby allowing the hydrogen ions in the subsequent hydrogen-containing passivation layer to be effectively released to the cross section 101, thereby passivating the damaged area of ​​the cross section 101, repairing the internal defects of the cross section 101, improving the passivation effect of the sliced ​​battery cell, and improving the performance of the sliced ​​battery cell.

[0067] refer to Figure 7 , Figure 7 This is a schematic structural diagram of the solar cell manufacturing method provided in this embodiment after the hydrogen-containing passivation layer is formed. In this embodiment, the hydrogen-containing passivation layer 104 is formed on the surface of the oxide layer 103 away from the cross section.

[0068] This embodiment forms a hydrogen-containing passivation layer 104 on the surface of the oxide layer 103 away from the cross section, providing a source of hydrogen ions 105 for subsequent hydrogen passivation activation treatment, so as to release the hydrogen ions 105 in the hydrogen-containing passivation layer 104 to the cross section 101, so as to passivate the damaged area of ​​the cross section 101, repair the internal defects of the cross section 101, improve the passivation effect of the sliced ​​battery cell, and improve the performance of the sliced ​​battery cell.

[0069] In some embodiments, the hydrogen-containing passivation layer may be deposited at low temperature using conventional ALD, or may be deposited using other methods, such as PECVD (Plasma Enhanced Chemical Vapor Deposition), CVD (Chemical Vapor Deposition), PCVD (Photo Chemical Vapor Deposition), PVD (Physical Vapor Deposition), laser-induced deposition, etc.

[0070] In some embodiments, the hydrogen-containing passivation layer 104 may be aluminum oxide. The hydrogen-containing passivation layer 104 may also be other hydrogen-containing materials, such as hydrogenated silicon nitride, hydrogenated amorphous silicon, hydrogenated silicon oxide, titanium dioxide, zinc oxide, etc.

[0071] In some embodiments, the thickness of the hydrogen-containing passivation layer 104 is greater than the thickness of the oxide layer 103. This configuration ensures that the hydrogen-containing passivation layer 104 can provide a sufficient source of hydrogen ions 105 to penetrate the oxide layer 103, so that the hydrogen ions 105 in the hydrogen-containing passivation layer 104 can be effectively released to the cross section 101, thereby passivating the damaged area of ​​the cross section 101, repairing the internal defects of the cross section 101, and improving the passivation effect of the sliced ​​solar cell.

[0072] In some embodiments, the thickness of the hydrogen-containing passivation layer 104 is 5 nm to 50 nm, for example, 5 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, or 50 nm. By setting the thickness of the hydrogen-containing passivation layer 104 within this range, on the one hand, the hydrogen-containing passivation layer 104 can provide a sufficient source of hydrogen ions 105, so that the hydrogen ions 105 in the hydrogen-containing passivation layer 104 can be effectively released to the cross section 101, thereby passivating the damaged area of ​​the cross section 101, repairing the internal defects of the cross section 101, and improving the passivation effect of the split cell. On the other hand, during the subsequent second laser treatment process, the surface state density of the split cell can be effectively reduced, the surface defects of the split cell can be reduced, and the performance of the formed split cell surface can be improved.

[0073] Since the lower the deposition temperature of the hydrogen-containing passivation layer 104, the higher the content of hydrogen ions 105 in the hydrogen-containing passivation layer 104, in some embodiments, the process temperature for depositing the hydrogen-containing passivation layer 104 is 200° C. to 300° C., for example, 200° C., 210° C., 220° C., 230° C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., or 300° C. By setting the process temperature for depositing the hydrogen-containing passivation layer 104 within this range, the temperature for depositing the hydrogen-containing passivation layer 104 is lower, which can increase the content of hydrogen ions 105 in the hydrogen-containing passivation layer 104. At the same time, the hydrogen-containing passivation layer 104 deposited at a low temperature can more effectively passivate defects on the surface of the cell and reduce the recombination rate on the cell surface. In addition, by setting the process temperature for depositing the hydrogen-containing passivation layer 104 within this range, the distribution of the hydrogen ions 105 in the hydrogen-containing passivation layer 104 can be more uniform, so that in the subsequent second laser processing process, the uniformly distributed hydrogen ions 105 can be evenly extended to the cross section 101, better passivate the damaged area of ​​the cross section 101, repair the internal defects of the cross section 101, improve the passivation effect of the sliced ​​battery cell, and improve the performance of the sliced ​​battery cell.

[0074] In this embodiment, after the hydrogen-containing passivation layer 104 is deposited, a second preheating treatment is performed on the surface of the hydrogen-containing passivation layer 104 away from the oxide layer 103 .

[0075] In this embodiment, by performing a second preheat treatment on the surface of the hydrogen-containing passivation layer 104 away from the oxide layer 103, the hydrogen-containing passivation layer 104 can be preheated so that the hydrogen-containing passivation layer 104 is preheated to a second preset temperature, thereby reducing the actual power of the subsequent second laser treatment, thereby reducing the negative effect of thermal damage to the hydrogen-containing passivation layer 104 caused by the second laser treatment, and thus improving the passivation effect of the formed hydrogen-containing passivation layer 104.

[0076] In some embodiments, the temperature of the second preheat treatment is lower than the temperature of the first preheat treatment, that is, the second preset temperature is lower than the first preset temperature. Since the subsequent second laser treatment is to release hydrogen ions in the hydrogen-containing passivation layer 104 into the damaged area of ​​the cross section 101 to repair internal lattice defects, the power of the second laser treatment is relatively small, and the corresponding temperature of the second preheat treatment is also relatively small. The first laser treatment is to perform deep oxidation, and the second oxidation treatment requires a relatively high temperature. Therefore, the power of the first laser treatment is larger than the power of the second laser treatment, and the corresponding temperature of the first preheat treatment is also larger than the temperature of the second preheat treatment. Through this setting, it can be ensured that the second preheat treatment can reduce the power of the subsequent second laser treatment while ensuring that the temperature of the second preheat treatment is relatively low, reducing the negative effect of thermal damage caused by the second preheat treatment on the hydrogen-containing passivation layer 104, thereby improving the passivation effect of the formed hydrogen-containing passivation layer 104.

[0077] In some embodiments, the temperature of the second preheat treatment is 50° C. to 100° C., for example, 50° C., 60° C., 70° C., 80° C., 90° C., or 100° C. By setting the temperature of the second preheat treatment within this range, on the one hand, the hydrogen-containing passivation layer 104 can be preheated, the power of the subsequent second laser treatment can be reduced, and damage to the hydrogen-containing passivation layer 104 caused by excessive power of the second laser treatment can be avoided. On the other hand, rapid temperature changes of the hydrogen-containing passivation layer 104 caused by excessively high temperature of the second preheat treatment can be avoided, ensuring uniform temperature distribution of the hydrogen-containing passivation layer 104, reducing performance differences caused by local overheating or overcooling, providing a hydrogen-containing passivation layer 104 with uniform temperature for the subsequent second laser treatment, and improving the passivation effect of the formed sliced ​​solar cell.

[0078] refer to Figure 8 , Figure 8 This is a schematic diagram of the structure after hydrogen passivation activation treatment in the solar cell preparation method provided in this embodiment. In this embodiment, hydrogen passivation activation treatment is performed on the surface of the hydrogen-containing passivation layer 104 away from the oxide layer 103 to release the hydrogen ions 105 in the hydrogen-containing passivation layer 104 to the cross section 101 to form a passivated sliced ​​cell.

[0079] In this embodiment, hydrogen ions 105 in the hydrogen-containing passivation layer 104 are released to the cross section 101 by performing a hydrogen passivation activation treatment on the hydrogen-containing passivation layer 104, so as to passivate the damaged area of ​​the cross section 101 and repair the internal defects of the cross section 101 to form a passivated sliced ​​battery cell, thereby improving the passivation effect of the sliced ​​battery cell and improving the performance of the sliced ​​battery cell.

[0080] In some embodiments, the hydrogen passivation activation process is a second laser process. The second laser process in this embodiment can be implemented using a red or green continuous wave laser, or a picosecond or nanosecond laser. The laser irradiates the hydrogen-containing passivation layer 104 perpendicular to the cross section, with a circular or square spot shape having a circular diameter or square size ranging from 1 mm to 2 mm, to activate hydrogen ions 105 enriched in the low-temperature deposited hydrogen-containing passivation layer 104, causing the hydrogen ions 105 to be released into the damaged area of ​​the cross section 101 to repair internal lattice defects.

[0081] In some embodiments, the energy of the second laser treatment is lower than the energy of the first laser treatment. Since the first laser treatment is for deep oxidation to form the oxide layer 103, and the second laser treatment is for releasing hydrogen ions in the hydrogen-containing passivation layer 104 into the damaged area of ​​the cross section 101 to repair internal lattice defects, the energy of the first laser treatment is greater than the energy of the second laser treatment, that is, the power of the second laser treatment is lower than the power of the first laser treatment, and the temperature of the second laser treatment is lower than the temperature of the first laser treatment. Through this setting, the second laser treatment can release hydrogen ions in the hydrogen-containing passivation layer 104 into the cross section 101 to passivate the damaged area of ​​the cross section 101 and repair the internal defects of the cross section 101. At the same time, it can also avoid the second laser treatment energy being too high, which may cause damage to the surface of the hydrogen-containing passivation layer 104, thereby improving the performance of the sliced ​​battery cell.

[0082] In some embodiments, the power of the second laser treatment is 80 W to 150 W, for example, 80 W, 90 W, 100 W, 110 W, 120 W, 130 W, 140 W, or 150 W. Because the second preheat treatment is performed on the cross section 101 before the second laser treatment, so that the temperature of the hydrogen-containing passivation layer 104 reaches the second preset temperature and the temperature distribution of the hydrogen-containing passivation layer 104 is uniform, the actual power of the second laser treatment can be set to a lower level, thereby reducing the power consumption of the second laser treatment. Moreover, even if the power of the second laser treatment is set within this range, the hydrogen ions 105 enriched in the hydrogen-containing passivation layer 104 can be released to the cross section 101. At the same time, the power of the second laser treatment is set within this range, which can also reduce the negative effects of thermal damage caused by the laser on the hydrogen-containing passivation layer 104, thereby improving the performance of the finally formed sliced ​​solar cell.

[0083] In some embodiments, during the second laser treatment, the laser scan speed is 1000 mm / s-30000 mm / s, for example, 1000 mm / s, 1500 mm / s, 2000 mm / s, 2500 mm / s, and 3000 mm / s. By setting the laser scan speed within this range, on the one hand, the problem of uneven hydrogen ion release to the cross section 101 due to excessively fast scan speeds can be avoided, and on the other hand, the problem of excessive thermal damage to the hydrogen-containing passivation layer 104 due to excessively slow scan speeds can be avoided, thereby improving the surface quality of the hydrogen-containing passivation layer 104 and enhancing the passivation effect of the hydrogen-containing passivation layer 104.

[0084] In some embodiments, the temperature of the second laser treatment is 300° C. to 750° C., for example, 300° C., 350° C., 400° C., 450° C., 500° C., 550° C., 600° C., 650° C., 700° C., or 750° C. By setting the temperature of the second laser treatment within this range, on the one hand, the hydrogen ions 105 enriched in the low-temperature deposited hydrogen-containing passivation layer 104 can be activated, ensuring that the hydrogen ions 105 of the hydrogen-containing passivation layer 104 can be quickly released into the damaged area of ​​the cross section 101 to repair internal lattice defects. On the other hand, since the second preheating treatment is performed on the cross section 101 before the second laser treatment, so that the temperature of the hydrogen-containing passivation layer 104 reaches the second preset temperature, the temperature of the second laser treatment is relatively low. During the second laser treatment, heat accumulation can be reduced, avoiding unnecessary thermal damage to the cell slices caused by the excessively high temperature of the second laser treatment, thereby improving the performance of the resulting cell slices.

[0085] In this embodiment, the above-mentioned solar cell preparation method is used to first perform a first preheat treatment on the cross section 101 of the initial sliced ​​cell 100 after division to form an initial oxide layer 102 with a nanometer-level thickness, and then perform a first laser treatment on the initial oxide layer 102. The laser focused energy is instantaneously released to heat the initial oxide layer 102 while spraying strong oxidizing chemical reagents such as hydrogen peroxide, thereby further enhancing the diffusion of oxygen into the damaged area of ​​the silicon substrate, saturating the Si-SiO2 dangling bonds, forming a denser oxide layer 103, and improving the passivation effect of the oxide layer 103. After depositing the hydrogen-containing passivation layer 104, the hydrogen-containing passivation layer 104 is subjected to a second laser treatment to activate the hydrogen ions 105 enriched in the hydrogen-containing passivation layer 104 to diffuse inward, thereby saturating the dangling bonds in the heat-affected zone and the crack damage zone generated during the slicing process and the first laser treatment, repairing lattice defects, and improving the performance of the sliced ​​cell.

[0086] In this embodiment, the performance of the final formed cell is further improved by the above-mentioned method for preparing solar cells, compared with the solution of only using ALD technology to deposit the mixed passivation layer in the related art. Figure 9, which is a schematic diagram of the structure of the hydrogen-containing passivation layer of this embodiment, it can be seen that the hydrogen-containing passivation layer 104 formed in this embodiment has good density and good passivation effect, thereby improving the performance of the formed sliced ​​solar cell, including reducing recombination, improving carrier transport, increasing the opening voltage and filling, and increasing power. Among them, by using the solar cell preparation method of this embodiment, the opening voltage of the prepared sliced ​​solar cell is increased by 0.3mV to 0.8mV, the filling is increased by 0.05 to 0.15, the efficiency of the sliced ​​solar cell is increased by 0.05% to 0.1%, and the power of the photovoltaic module formed by the sliced ​​solar cell is increased by 0.5W to 1W.

[0087] Another embodiment of the present application provides a solar cell, such as Figure 8 , which is a schematic structural diagram of a solar cell according to this embodiment, includes: passivated sliced ​​cells prepared by the solar cell preparation method according to the above embodiment.

[0088] The split cell includes an initial split cell 100 having a cross section 101 ; an oxide layer 103 covering the cross section; and a hydrogen-containing passivation layer 104 covering a surface of the oxide layer 103 away from the cross section 101 .

[0089] refer to Figures 3 to 8 The sliced ​​cell in the solar cell of this embodiment is prepared by the solar cell preparation method of the above embodiment. The oxide layer 103 is formed by oxidizing the cross section 101 of the initial sliced ​​cell. The oxide layer 103 can saturate the dangling bonds on the cross section to improve the passivation effect. After the hydrogen-containing passivation layer 104 is deposited on the oxide layer 103, the surface of the hydrogen-containing passivation layer 104 away from the oxide layer 103 is subjected to hydrogen passivation activation treatment to release hydrogen ions 105 in the hydrogen-containing passivation layer 104 to the cross section 101, so as to passivate the damaged area of ​​the cross section 101 and repair the internal defects of the cross section 101 to form the passivated sliced ​​cell, thereby improving the passivation effect of the sliced ​​cell and improving the performance of the sliced ​​cell.

[0090] The solar cells of this embodiment will form a photovoltaic module after assembly. During the assembly process of the photovoltaic module, welding strips are formed on the split battery cells, and the split battery cells are welded together by welding strips to form a battery string. Multiple battery strings are connected in series or in parallel according to the design requirements to form a complete battery module string, and then stacking, lamination, trimming, framing, and installation of junction boxes are performed to form a photovoltaic module. Since the photovoltaic module is composed of the solar cells of this embodiment, and since the solar cells of this embodiment have a good passivation effect, the power of the formed photovoltaic module is improved. It can be understood by those of ordinary skill in the art that the above-mentioned embodiments are specific embodiments for realizing the present application, and in actual applications, various changes can be made to them in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art can make various 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 based on the scope defined by the claims.

Claims

1. A method for preparing a solar cell, characterized in that: include: Providing an initially sliced ​​cell having a cross section; performing an oxidation treatment on the cross section to form an oxide layer to saturate dangling bonds on the cross section; forming a hydrogen-containing passivation layer on a surface of the oxide layer away from the cross section; Performing a hydrogen passivation activation treatment on the surface of the hydrogen-containing passivation layer away from the oxide layer to release hydrogen ions in the hydrogen-containing passivation layer to the cross section to form a passivated sliced ​​battery cell; The step of performing oxidation treatment on the cross section to form an oxide layer comprises: performing a first preheating treatment on the cross section to preheat the temperature of the cross section to a first preset temperature and form an initial oxide layer on the cross section; performing a second oxidation treatment on the initial oxide layer, so that the initial oxide layer is oxidized to form the oxide layer; The second oxidation treatment is: performing a first laser treatment on the initial oxide layer in an oxygen-rich environment.

2. The method for preparing a solar cell according to claim 1, wherein: The hydrogen passivation activation treatment is a second laser treatment, wherein the energy of the second laser treatment is lower than the energy of the first laser treatment.

3. The method for preparing a solar cell according to claim 1, wherein: Before performing hydrogen passivation activation treatment on the surface of the hydrogen-containing passivation layer away from the oxide layer, the method includes: A second preheating treatment is performed on the surface of the hydrogen-containing passivation layer away from the oxide layer; the temperature of the second preheating treatment is lower than the temperature of the first preheating treatment.

4. The method for preparing a solar cell according to claim 1, wherein: The thickness of the hydrogen-containing passivation layer is greater than that of the oxide layer; the thickness of the oxide layer is 5 nm to 10 nm, and the thickness of the hydrogen-containing passivation layer is 5 nm to 50 nm.

5. The method for preparing a solar cell according to claim 2, wherein: The power of the first laser treatment is 150W to 300W, and the temperature of the first laser treatment is 500°C to 1000°C; the power of the second laser treatment is 80W to 150W, and the temperature of the second laser treatment is 300°C to 750°C.

6. The method for preparing a solar cell according to claim 3, wherein: The temperature of the first preheating treatment is 100°C to 300°C; the temperature of the second preheating treatment is 50°C to 100°C.

7. The method for preparing a solar cell according to claim 1, wherein: The duration of the first preheating treatment is longer than that of the second oxidation treatment; the duration of the first preheating treatment is 600s to 900s; the duration of the second oxidation treatment is 100s to 500s.

8. A solar cell, characterized in that: include: The passivated split cell prepared by the solar cell preparation method according to any one of claims 1 to 7.

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