Photovoltaic cell, preparation method thereof and photovoltaic module

Abstract

The embodiment of the invention relates to the field of photovoltaic cells, and provides a photovoltaic cell, a preparation method thereof and a photovoltaic module, and the preparation method of the photovoltaic cell comprises the steps: providing a semiconductor substrate; forming an initial electrode on the semiconductor substrate through a metallization heat treatment process; radiating the semiconductor substrate by adopting a carrier excitation source to sinter the initial electrode to form a finished electrode; wherein the execution times of radiating the semiconductor substrate by adopting the carrier excitation source are at least two times; the area size S of the semiconductor substrate and the power value P of the carrier excitation source meet the condition that P / S is larger than or equal to 0.048 W / cm < 2 > and smaller than or equal to 0.092 W / cm < 2 >. The embodiment of the invention at least can solve the problem that high-resistance ohmic contact is formed due to poor metalized contact effect of the electrode and the semiconductor substrate in the photovoltaic cell.

Description

Technical Field

[0001] This application relates to the field of photovoltaic cells, and particularly to a photovoltaic cell, a preparation method thereof, and a photovoltaic module. Background Art

[0002] A photovoltaic cell is a photoelectric semiconductor thin sheet that directly generates electricity using sunlight. Under a certain illumination intensity of light, the photovoltaic cell can output voltage and generate current. The structure of the photovoltaic cell includes electrodes, which are usually obtained by metallization treatment. The electrodes are metallized and contacted with the semiconductor substrate, and an ohmic contact is formed between the two. Forming a good ohmic contact is beneficial to the input and output of current. Summary of the Invention

[0003] Embodiments of this application provide a photovoltaic cell, a preparation method thereof, and a photovoltaic module, which are at least beneficial to solving the problem of poor metallization contact effect between the electrodes and the semiconductor substrate in the photovoltaic cell, resulting in a high-resistance ohmic contact between the two.

[0004] According to some embodiments of this application, on the one hand, an embodiment of this application provides a preparation method of a photovoltaic cell, including: Providing a semiconductor substrate; Forming an initial electrode on the semiconductor substrate through a metallization heat treatment process; Radiating the semiconductor substrate with a carrier excitation source to sinter the initial electrode to form a finished electrode; Wherein, the number of executions of radiating the semiconductor substrate with the carrier excitation source is at least two times; for the area size S of the semiconductor substrate and the power value P of the carrier excitation source, it satisfies 0.048W / cm 2 ≤P / S≤0.092W / cm 2 .

[0005] In some embodiments, the power value of the carrier excitation source for radiating the semiconductor substrate for the first time is greater than or equal to the power value of the carrier excitation source for radiating the semiconductor substrate for the second time.

[0006] In some embodiments, the ratio range of the power value of the carrier excitation source for radiating the semiconductor substrate for the first time to the power value of the carrier excitation source for radiating the semiconductor substrate for the second time is 1 to 1.4.

[0007] In some embodiments, the power value range of the carrier excitation source is 10W to 50W.

[0008] In some embodiments, while radiating the semiconductor substrate with the carrier excitation source, a reverse bias voltage is applied to the semiconductor substrate.

[0009] In some embodiments, for the voltage value U of the reverse bias voltage and the area size S of the semiconductor substrate, it satisfies 54 mV / cm 2 ≤U / S≤68 mV / cm 2 .

[0010] In some embodiments, the voltage value of the reverse bias voltage applied to the semiconductor substrate for the first time is greater than or equal to the voltage value of the reverse bias voltage applied to the semiconductor substrate for the second time.

[0011] In some embodiments, the ratio range of the voltage value of the reverse bias voltage applied to the semiconductor substrate for the first time to the voltage value of the reverse bias voltage applied to the semiconductor substrate for the second time is 1 to 1.2.

[0012] In some embodiments, the voltage value of the reverse bias voltage is 10 V to 30 V.

[0013] In some embodiments, while the carrier excitation source irradiates the semiconductor substrate, a current is applied to the semiconductor substrate.

[0014] In some embodiments, for the current value I of the current, it satisfies 6 mA / cm 2 ≤I / S≤15 mA / cm 2 .

[0015] In some embodiments, the current value of the current applied to the semiconductor substrate for the first time is greater than or equal to the current value of the current applied to the semiconductor substrate for the second time.

[0016] In some embodiments, the ratio range of the current value of the current applied to the semiconductor substrate for the first time to the current value of the current applied to the semiconductor substrate for the second time is 1 to 1.2.

[0017] In some embodiments, the current value of the current is 2 A to 7 A.

[0018] In some embodiments, the area size of the semiconductor substrate is 100 cm 2 ~600 cm 2 .

[0019] In some embodiments, the length of the finished electrode is 5 cm to 100 cm, and the width of the finished electrode is 2 μm to 60 μm.

[0020] In some embodiments, the method for forming the initial electrode through the metallization heat treatment process includes: performing screen printing treatment on the semiconductor substrate to form a paste grid line; performing thermal sintering treatment on the paste grid line to form the initial electrode.

[0021] In some embodiments, the sintering temperature of the thermal sintering treatment is 600°C to 880°C, and the sintering time of the thermal sintering treatment is 30s to 120s.

[0022] According to some embodiments of the present application, on the other hand, the present application embodiments further provide a photovoltaic cell, which is obtained by the preparation method of the photovoltaic cell as described above.

[0023] In some embodiments, the photovoltaic cell includes at least one of a PERC cell, a TOPCon cell, or a BC cell.

[0024] According to some embodiments of the present application, on the other hand, the present application embodiments further provide a photovoltaic module, including: a battery string formed by connecting a plurality of photovoltaic cells; An encapsulation adhesive film for covering the surface of the battery string; A cover plate for covering the surface of the encapsulation adhesive film facing away from the battery string; Wherein, the photovoltaic cell is obtained by the preparation method of the photovoltaic cell as described in any one of the above, or the photovoltaic cell as described above.

[0025] The technical solutions provided by the embodiments of the present application have at least the following advantages: The number of executions of the carrier excitation source for irradiating the semiconductor substrate is greater than or equal to two, which is beneficial to ensuring a relatively high sintering degree of the finished electrode and enhancing the conductivity and uniformity of the metallization contact between the finished electrode and the semiconductor substrate. The power of the carrier excitation source is proportional to the area of the semiconductor substrate, avoiding local overheating due to too large a power of the carrier excitation source for a small-sized semiconductor substrate, resulting in damage to the semiconductor substrate caused by excessive thermal stress, or avoiding poor metallization contact effect between the finished electrode and the semiconductor substrate and large contact resistance due to too small a power of the carrier excitation source for a large-sized semiconductor substrate, leading to a reduction in the photoelectric conversion efficiency of the photovoltaic cell. Description of the Drawings

[0026] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments unless otherwise stated. The figures in the drawings do not constitute a scale limitation; in order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the following-described drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 It is a step flow chart of a preparation method of a photovoltaic cell provided by the embodiments of the present application; Figure 2 Schematic structural diagram of a semiconductor substrate in a method for manufacturing a photovoltaic cell provided by an embodiment of the present application; Figure 3 Schematic structural diagram after forming a paste electrode in a method for manufacturing a photovoltaic cell provided by an embodiment of the present application; Figure 4 Schematic structural diagram after forming an initial electrode in a method for manufacturing a photovoltaic cell provided by an embodiment of the present application; Figure 5 Schematic structural diagram after forming a finished electrode in a method for manufacturing a photovoltaic cell provided by an embodiment of the present application.

[0028] In the figure: 100, semiconductor substrate; 110, substrate; 120, dielectric layer; 130, doped layer; 210, paste electrode; 220, initial electrode; 230, finished electrode. Detailed implementation manners

[0029] As can be seen from the background art, the electrode is in metallized contact with the semiconductor substrate, and an ohmic contact is formed between the two. A poor metallized contact effect will cause the contact resistance between the electrode and the semiconductor substrate to increase. On the contrary, a good metallized contact will reduce the contact resistance between the electrode and the semiconductor, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0030] In the production of photovoltaic cells in the related art, the way of combining the conductive material with the surface of the semiconductor substrate usually adopts a sintering process, which is a key step in the electrode preparation process. The sintering quality of the electrode directly affects the metallized contact effect between the electrode and the semiconductor substrate. The traditional sintering process usually adopts high-temperature sintering. This method can achieve the solidification of the paste and the formation of the electrode. However, on the one hand, the sintering process of the high-temperature furnace sintering process may cause damage to the semiconductor substrate in the non-electrode area; on the other hand, due to the lack of fine control, it is impossible to perform optimization processing on local areas, resulting in an irrational metallized contact effect between the electrode and the semiconductor substrate, thus affecting the photoelectric conversion efficiency and stability of the photovoltaic cell.

[0031] The present application provides a method for preparing a photovoltaic cell. The technical solution is to use a carrier excitation source to irradiate the initial electrode that has completed the metallization heat treatment process. On the one hand, when the carrier excitation source irradiates the initial electrode, it causes instantaneous high temperature in the initial electrode and the corresponding region of the semiconductor substrate, enabling the materials of the initial electrode and the semiconductor substrate to form a eutectic diffusion, thereby improving the metallization contact effect between the finally formed finished electrode and the semiconductor substrate, reducing the contact resistance between the finished electrode and the semiconductor substrate, and further improving the photoelectric conversion efficiency of the photovoltaic cell. On the other hand, when the carrier excitation source irradiates the initial electrode, it also irradiates the semiconductor substrate in the non-electrode region to excite carriers, forming a local current, which further promotes the temperature rise of the initial electrode and helps the initial electrode and the semiconductor substrate to further eutectically interdiffuse. The number of times the carrier excitation source irradiates the initial electrode is greater than or equal to two, which is beneficial to ensuring the sintering degree of the finished electrode and enhancing the conductivity and uniformity of the metallization contact between the finished electrode and the semiconductor substrate.

[0032] In the embodiments of the present application, the power of the carrier excitation source is proportional to the area of the semiconductor substrate, avoiding local overheating due to a large power of the carrier excitation source for a small-sized semiconductor substrate, which may cause damage to the semiconductor substrate due to excessive thermal stress, or avoiding poor metallization contact effect between the finished electrode and the semiconductor substrate and large contact resistance due to a small power of the carrier excitation source for a large-sized semiconductor substrate, resulting in a reduction in the photoelectric conversion efficiency of the photovoltaic cell.

[0033] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined. Similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0034] Referring to "embodiments" herein means that the specific features, structures, or characteristics described in connection with the embodiments may be included in at least one embodiment of the present application. The phrase appearing at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein may be combined with other embodiments.

[0035] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " in this text generally represents an "or" relationship between the associated objects before and after.

[0036] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. This is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the embodiments of the present application.

[0037] For example, if the device or element in the figure is inverted, then the element described as "below" or "beneath" or "under" or "bottom" of other elements or features will be oriented "above" or "on top of" the other elements or features. Therefore, the term "below" can cover both the above and below orientations depending on the context in which the term is used, which will be obvious to those of ordinary skill in the art. The material can be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatial relative descriptive terms used herein can be interpreted accordingly.

[0038] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside 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 application can be understood according to specific circumstances.

[0039] In the corresponding drawings of the embodiments of the present application, for better understanding and convenience of description, the thickness and area of the layer are enlarged. In addition, when describing that a component is "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 on a partial edge of the entire surface.

[0040] In the description of the embodiments of the present application, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. Forming or disposing a second component above or on a first component, or forming or disposing a second component on the surface of the first component, or forming or disposing a second component on one side of the first component may include embodiments where the first component and the second component are in direct contact, and may also include embodiments where additional components may be present between the first component and the second component such that the first component and the second component are not in direct contact. For simplicity and clarity, various components may be drawn at arbitrary scales. In the drawings, some layers / components may be omitted for simplicity. Unless otherwise specified, forming or disposing a second component on the surface of the first component means that the first component is in direct contact with the second component. Among them, the above "component" may refer to a layer, a film, a region, a part, a structure, etc.

[0041] The terms used in the description of various embodiments herein are only for the purpose of describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "component" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, components include components such as layers, films, regions, or plates.

[0042] The following will elaborate on the various embodiments of the present application in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in the various embodiments of the present application, many technical details are provided to help the reader better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0043] Figure 1 It is a flowchart of the steps of a method for manufacturing a photovoltaic cell provided for the embodiments of the present application.

[0044] Refer to Figure 1 , the method for manufacturing a photovoltaic cell includes: Providing a semiconductor substrate 100; Forming an initial electrode 220 on the semiconductor substrate 100 through a metallization heat treatment process; Radiating the semiconductor substrate 100 with a carrier excitation source to sinter the initial electrode 220 to form a finished electrode 230; Among them, the number of times of radiating the semiconductor substrate 100 with a carrier excitation source is at least two; for the area size S of the semiconductor substrate 100 and the power value P of the carrier excitation source, it satisfies 0.048 W / cm 2 ≤P / S≤0.092W / cm 2 .

[0045] In this application, the carrier excitation source irradiates the semiconductor substrate 100 multiple times to sinter the initial electrode 220, so as to enhance the conductivity and uniformity of the metallized contact between the finished electrode 230 and the semiconductor substrate 100, ensure the continuity of the finished electrode 230, and reduce the contact resistance. The power of the carrier excitation source in this application is proportional to the area size of the semiconductor substrate 100, so as to reduce the risk of local overheating or low metallization degree caused by the mismatch between the power of the carrier excitation source and the area size of the semiconductor substrate 100.

[0046] The embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0047] Refer to Figure 1 as shown, Figure 1 The flowchart of the steps of a method for manufacturing a photovoltaic cell according to an embodiment of this application is shown, including: Step S1, provide a semiconductor substrate 100. The semiconductor substrate 100 has a first direction X, a second direction Y, and a third direction Z that intersect and are perpendicular to each other, where the second direction Y is the thickness direction of the semiconductor substrate 100. The semiconductor substrate 100 has opposite first and second surfaces in the second direction Y.

[0048] It should be noted that for a single-sided cell, the first surface is the backlight surface, and the second surface can be used to receive incident light; for a double-sided cell, both the first surface and the second surface are light-receiving surfaces, and both the first surface and the second surface can be used to receive incident light.

[0049] Combined with Figure 2 as shown, Figure 2 The schematic structural diagram of the semiconductor substrate 100 in a method for manufacturing a photovoltaic cell according to an embodiment of this application is shown. The semiconductor substrate 100 includes a substrate 110, a dielectric layer 120, and a doped layer 130 arranged in sequence along the second direction Y. The dielectric layer 120 and the doped layer 130 are arranged on one side of the substrate 110 facing the first surface in sequence.

[0050] In some embodiments, the material of the doped layer 130 includes at least one of doped polysilicon, doped single-crystalline silicon, or doped amorphous silicon.

[0051] In some embodiments, the dielectric layer 120 is sandwiched between the substrate 110 and the doped layer 130. The dielectric layer 120 can play a role in chemically passivating the substrate 110. In addition, the dielectric layer 120 can cause an asymmetric shift in the energy band of the first surface of the substrate 110, such that the potential barrier for majority carriers in the carriers is lower than the potential barrier for minority carriers in the carriers. Therefore, the majority carriers can more easily perform quantum tunneling through the dielectric layer 120, while the minority carriers are difficult to pass through the dielectric layer 120, so as to achieve selective transport of carriers.

[0052] The material of the dielectric layer 120 includes at least one of silicon oxide, silicon nitride, and silicon oxynitride.

[0053] Step S2: Form an initial electrode 220 on the semiconductor substrate 100 through a metallization heat treatment process.

[0054] Combined Figure 3 、 Figure 4 as shown, Figure 3 and Figure 4 respectively show a schematic structural diagram after forming the paste electrode 210 and a schematic structural diagram after forming the initial electrode 220 in a method for preparing a photovoltaic cell according to an embodiment of the present application. The method for forming the initial electrode 220 on the semiconductor substrate 100 through a metallization heat treatment process includes: Step S21: First form a paste electrode 210 on the first surface of the semiconductor substrate 100. The paste electrode 210 is formed by printing a conductive paste on the first surface of the semiconductor substrate 100.

[0055] Step S22: Perform a thermal sintering treatment on the paste electrode 210 to cure the paste electrode 210 to form the initial electrode 220. Among them, at least a part of the initial electrode 220 forms a metallized contact with the doping layer 130 in the semiconductor substrate 100.

[0056] In some embodiments, the method for forming the paste electrode 210 by printing a conductive paste includes at least one of a screen printing process, a gravure printing process, a relief printing process, a flexographic printing process, a laser transfer printing process, an inkjet printing process, and a 3D printing process.

[0057] In some embodiments, the conductive paste can be a silver paste or an aluminum paste, or a silver-aluminum mixed paste.

[0058] The thermal sintering treatment refers to a traditional high-temperature sintering process. The semiconductor substrate 100 printed with the paste electrode 210 is placed in a high-temperature environment (such as a sintering furnace) to achieve the curing of the paste electrode 210 and the formation of the initial electrode 220. Before irradiating the initial electrode 220 with a carrier excitation source, first perform a thermal sintering treatment on the paste electrode 210 to cure it to form the initial electrode 220, so that the conductive particles in the paste can be evenly dispersed and fixed in the initial electrode 220. Although the instantaneous high temperature generated by directly irradiating the paste electrode 210 with the carrier excitation source can also cure the paste electrode 210, the paste electrode 210 in a paste state will have a situation where conductive particles aggregate or detach when irradiated by the carrier excitation source. Therefore, performing a thermal sintering treatment on the paste electrode 210 before irradiating it with the carrier excitation source to cure it to form the initial electrode 220 improves the quality and reliability of the finished electrode 230.

[0059] In some embodiments, the sintering temperature of the thermal sintering treatment is 600°C to 880°C, and the sintering time of the thermal sintering treatment is 30 s to 120 s.

[0060] In some embodiments, a passivation layer (not shown in the figure) is further disposed on the surface of the doping layer 130 facing away from the substrate 110. The paste electrode 210 or the initial electrode 220 penetrates the passivation layer along the second direction Y and is at least partially embedded in the doping layer 130. The passivation layer has an insulating and isolating effect and is used to protect the doping layer 130. The finished electrode 230 is formed by sintering the initial electrode 220. Therefore, the finished electrode 230 penetrates the passivation layer and is at least partially embedded in the doping layer 130.

[0061] The material of the passivation layer includes at least one of silicon oxide, aluminum oxide, silicon nitride, silicon carbide, or silicon oxynitride.

[0062] Step S3, combination Figure 5 as shown Figure 5 FIG. shows a schematic structural diagram after forming the finished electrode 230 in a method for manufacturing a photovoltaic cell according to an embodiment of the present application. A carrier excitation source is used to irradiate the semiconductor substrate 100 to sinter the initial electrode 220 to form the finished electrode 230. The finished electrode 230 forms a metallization contact with the doping layer 130 in the semiconductor substrate 100. Compared with the metallization contact formed between the initial electrode 220 and the doping layer 130 in the previous step, the metallization contact formed between the finished electrode 230 and the doping layer 130 is deeper, and there is better ohmic contact ability and lower contact resistance between the two.

[0063] The method of using a carrier excitation source to irradiate the semiconductor substrate 100 includes: the carrier excitation source irradiates the first surface of the semiconductor substrate 100, and a light spot will be formed on the first surface of the semiconductor substrate 100. Wherein, the first surface of the semiconductor substrate 100 is the surface of the doping layer 130 in the semiconductor substrate 100. During the movement of the carrier excitation source or the movement of the radiation direction of the carrier excitation source, the area where the initial electrode 220 is located on the first surface is covered by the area irradiated by the light spot formed by the radiation of the carrier excitation source.

[0064] During the process of irradiating the semiconductor substrate 100 with the carrier excitation source, the initial electrode 220 and the doping layer 130 in its area generate instantaneous high temperature, causing the materials of the initial electrode 220 and the doping layer 130 to form a eutectic diffusion. The metallization contact between the finished electrode 230 and the doping layer 130 is deepened to form a tiny alloy junction to form the finished electrode 230. The finished electrode 230 forms a deeper metallization contact with the doping layer 130 compared with the initial electrode 220. A good ohmic contact is formed between the finished electrode 230 and the doping layer 130, and there is a low contact resistance between the two.

[0065] After the first carrier excitation source completes the radiation treatment of the semiconductor substrate 100, at least one more radiation treatment of the carrier excitation source is performed on the semiconductor substrate 100. For each radiation treatment of the carrier excitation source on the semiconductor substrate 100, the degree of metallization contact between the finished electrode 230 and the doped layer 130 and the uniformity of the finished electrode 230 are both improved to a certain extent compared with the previous time, and the contact resistance between the finished electrode 230 and the doped layer 130 is further reduced, thereby improving the photoelectric conversion efficiency of the photovoltaic cell.

[0066] In some embodiments, the shape of the light spot includes, but is not limited to, shapes such as rectangular, circular, elliptical or linear (i.e., a long strip-shaped light spot). The shape of the light spot can be selected according to actual usage requirements and will not be specifically limited here.

[0067] In some embodiments, the carrier excitation source performs continuous moving radiation on the semiconductor substrate 100, that is, the carrier excitation source moves along a path to radiate the semiconductor substrate 100, and both the moving process and the radiation process can be regarded as continuous.

[0068] However, the carrier excitation source can be continuously or intermittently operated through a controller, and thus the radiation of the carrier excitation source can be continuous radiation or intermittent radiation.

[0069] In other embodiments, during the radiation process of the carrier excitation source on the semiconductor substrate 100, the carrier excitation source performs intermittent radiation on the semiconductor substrate 100, and the moving path of the carrier excitation source can also be discontinuous, but ultimately the carrier excitation source radiates all areas where the initial electrode 220 or the finished electrode 230 is located. The radiation mode and the moving path of the carrier excitation source can be selected according to actual usage requirements and will not be specifically limited here.

[0070] Furthermore, the power of the carrier excitation source is proportional to the area size of the semiconductor substrate 100. In other words, the power of the carrier excitation source increases proportionally as the area size of the semiconductor substrate 100 increases or decreases proportionally as the area size of the semiconductor substrate 100 decreases. The design that the power of the carrier excitation source is proportional to the area size of the semiconductor substrate 100 avoids local overheating caused by too large a power of the carrier excitation source for a small area size of the semiconductor substrate 100, resulting in excessive thermal stress and damage to the semiconductor substrate 100, or avoids poor metallization contact between the finished electrode 230 and the semiconductor substrate 100 and a large contact resistance due to too small a power of the carrier excitation source for a large area size of the semiconductor substrate 100, leading to a reduction in the photoelectric conversion efficiency of the photovoltaic cell.

[0071] In some embodiments, the power of the carrier excitation source is power P, and the area size of the semiconductor substrate 100 is area S, satisfying 0.048 W / cm 2 ≤ P / S ≤ 0.092 W / cm 2 . Optionally, 0.05 W / cm 2 ≤ P / S ≤ 0.08 W / cm 2 , and the ratio P / S between the power of the carrier excitation source and the area size of the semiconductor substrate 100 can be 0.05 W / cm 2 , 0.06 W / cm 2 , 0.07 W / cm 2 or 0.08 W / cm 2 .

[0072] In some embodiments, the power range of the carrier excitation source is 10 W to 50 W. Optionally, the power range of the carrier excitation source is 15 W to 45 W, and the power of the carrier excitation source can be 15 W, 25 W, 30 W, or 40 W.

[0073] In some embodiments, the area size range of the semiconductor substrate 100 is 100 cm 2 ~600 cm 2 . Optionally, the area size range of the semiconductor substrate 100 is 200 cm 2 ~500 cm 2 , and the area size of the semiconductor substrate 100 can be 200 cm 2 , 300 cm 2 , 400 cm 2 or 500 cm 2 . The area size of the semiconductor substrate 100 is set within a suitable range to avoid problems such as low power generation and low photoelectric conversion efficiency of a single semiconductor substrate 100 due to too small an area size of the semiconductor substrate 100, or problems such as increased preparation difficulty and yield due to too large an area size of the semiconductor substrate 100.

[0074] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding examples and comparative examples are provided below for description. The photovoltaic cells produced from the following examples and comparative examples, where the number of times the carrier excitation source irradiates the semiconductor substrate 100 is two, and the power of the carrier excitation source is equal for both times. The photovoltaic cells are tested for their power using a digital source meter device under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius. Among them, AM1.5G simulated sunlight is used to simulate the spectral distribution of solar radiation under normal atmospheric conditions on the earth. The condition parameters not shown in the table are the same for both the examples and the comparative examples. Please refer to the following table specifically: Table 1:

[0075] As can be seen from Examples 1 to 6 and Comparative Examples 1 to 4 in Table 1, when the area sizes of the semiconductor substrate 100 are all 400 cm 2 , the ratio P / S between the power of the carrier excitation source and the area size of the semiconductor substrate 100 in Examples 1 to 6 is within the range of 0.048 W / cm 2~ to 0.092 W / cm 2 . The ratio P / S between the power of the carrier excitation source and the area size of the semiconductor substrate 100 in Comparative Examples 1 to 4 is outside the range of 0.048 W / cm 2 to 0.092 W / cm 2 . The open-circuit voltage and conversion efficiency of the photovoltaic cells in Examples 1 to 6 are higher than those of Comparative Examples 1 to 4. Among them, compared with Comparative Examples 1 to 4, the conversion efficiency of the photovoltaic cells in Examples 1 to 6 is increased by at least 0.05%.

[0076] Thus, it can be seen that when the ratio P / S between the power of the carrier excitation source and the area size of the semiconductor substrate 100 is within the range of 0.048 W / cm 2 to 0.092 W / cm 2 in the embodiments of the present application, the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0077] Furthermore, in the steps of irradiating the semiconductor substrate 100 with the carrier excitation source multiple times, the power of the carrier excitation source for sintering the initial electrode 220 or the finished electrode 230 for the first time is greater than or equal to the power of the carrier excitation source for sintering the finished electrode 230 for the subsequent time. Since a carrier excitation source with a greater power can provide a higher energy output in a shorter time and accelerate the mutual melting and diffusion between the initial electrode 220 and the doping layer 130, therefore, the radiation of the carrier excitation source with a greater power for the first time can more quickly control the grain growth of the finished electrode 230, making it more uniform and finer, further optimizing the interfacial contact between the finished electrode 230 and the doping layer 130, and reducing interface defects and recombination centers. The subsequent carrier excitation source with a smaller power finely adjusts the formed ohmic contact, improves the sintering sufficiency of the finished electrode 230 while improving the situation of overheating damage of the finished electrode 230, and improves the conductivity and stability of the finished electrode 230. In this way, the process window and the adaptability of the process can be expanded.

[0078] It can be understood that for initial electrodes 220 and semiconductor substrates 100 of different types and sizes, the power of the carrier excitation source can be flexibly adjusted as needed. For example, for some metal electrode materials with relatively high melting points, sintering can be promoted by a higher power of the carrier excitation source. For another example, for the relatively fragile semiconductor substrate 100, a previously higher-power carrier excitation source ensures metallization contact between the finished electrode 230 and the doped layer 130, and a subsequent lower-power carrier excitation source can reduce damage to the semiconductor substrate 100. Thus, the design of gradually decreasing the power of the carrier excitation source multiple times can improve process flexibility and adaptability.

[0079] In some embodiments, the ratio range between the power of the carrier excitation source for sintering the initial electrode 220 or the finished electrode 230 for the first time and the power of the carrier excitation source for sintering the finished electrode 230 for the second time is 1 to 1.4. Optionally, the ratio between the power of the carrier excitation source for sintering the initial electrode 220 for the first time and the power of the carrier excitation source for sintering the initial electrode 220 for the second time can be 1.02, 1.1, 1.2, or 1.3.

[0080] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding embodiments and comparative examples are provided below for description. The photovoltaic cells produced from the following embodiments and comparative examples are tested for their power using a digital source meter device under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius. The condition parameters not shown in the table are the same for both the embodiments and the comparative examples. Specifically, refer to the following table: Table 2:

[0081] It can be seen from Embodiments 7 to 12 and Comparative Examples 5 to 8 in Table 2 that when the area size of the semiconductor substrate 100 is 400 cm 2 and the power of the first carrier excitation source irradiating the semiconductor substrate 100 is 20 W, the ratio range between the power of the carrier excitation source for sintering the initial electrode 220 or the finished electrode 230 for the first time and the power of the carrier excitation source for sintering the finished electrode 230 for the second time in Embodiments 7 to 12 is 1 to 1.4, and the ratio between the power of the carrier excitation source for sintering the initial electrode 220 or the finished electrode 230 for the first time and the power of the carrier excitation source for sintering the finished electrode 230 for the second time in Comparative Examples 5 to 8 is greater than 1.4 or less than 1. The open-circuit voltage and conversion efficiency of the photovoltaic cells in Embodiments 7 to 12 are higher than those of Comparative Examples 5 to 8. Among them, compared with Comparative Examples 5 to 8, the conversion efficiency of the photovoltaic cells in Embodiments 7 to 12 is increased by at least 0.04%.

[0082] It can be seen that when the power of the carrier excitation source for sintering the initial electrode 220 or the finished electrode 230 once is greater than or equal to the power of the carrier excitation source for sintering the finished electrode 230 the second time, and the ratio between the two is in the range of 1 to 1.4, the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0083] Furthermore, while the carrier excitation source irradiates the semiconductor substrate 100 to sinter the initial electrode 220 or the finished electrode 230, a reverse bias voltage is applied to the semiconductor substrate 100, that is, a bias voltage in a direction opposite to the PN junction polarity of the light-receiving surface of the semiconductor substrate 100 is applied to the semiconductor substrate 100. When the carrier excitation source irradiates the semiconductor substrate 100, carriers are excited in the area of the semiconductor substrate 100 not covered by the initial electrode 220 or the finished electrode 230 by the radiation of the carrier excitation source. When a reverse bias voltage is applied to the semiconductor substrate 100, these excited charge carriers will move directionally to generate a local current. This local current can further increase the sintering temperature of the initial electrode 220 or the finished electrode 230, and promote further mutual melting and co-diffusion of the finished electrode 230 and the doping layer 130, thereby further improving the ohmic contact performance between the finished electrode 230 and the doping layer 130.

[0084] Furthermore, the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 is proportional to the size area of the semiconductor substrate 100. In other words, the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 increases proportionally as the area size of the semiconductor substrate 100 increases or decreases proportionally as the area size of the semiconductor substrate 100 decreases. The design that the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 is proportional to the area size of the semiconductor substrate 100 avoids excessive local current and local overheating of the semiconductor substrate 100 caused by too large a voltage value of the reverse bias voltage applied to the semiconductor substrate 100 with a small area size of the semiconductor substrate 100, resulting in excessive thermal stress and damage to the semiconductor substrate 100, or avoids poor metallization contact effect between the finished electrode 230 and the semiconductor substrate 100 and large contact resistance due to too small a voltage value of the reverse bias voltage with a large area size of the semiconductor substrate 100, leading to a reduction in the photoelectric conversion efficiency of the photovoltaic cell.

[0085] In some embodiments, for the voltage value U of the reverse bias voltage and the size area S of the semiconductor substrate 100, it satisfies 54 mV / cm 2 ≤U / S≤68 mV / cm 2 . Optionally, the ratio U / S between the voltage value of the reverse bias voltage and the size area of the semiconductor substrate 100 can be 58 mV / cm 2 、60 mV / cm2 , 62 mV / cm 2 or 64 mV / cm 2 .

[0086] In some embodiments, the voltage value range of the reverse bias voltage applied to the semiconductor substrate 100 is 10 V to 30 V. Optionally, the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 can be 14 V, 18 V, 22 V or 26 V.

[0087] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding embodiments and comparative examples are provided below for description. The number of executions of the carrier excitation source irradiating the semiconductor substrate 100 is two times, and the power of the two carrier excitation sources is the same. The photovoltaic cells obtained from the following embodiments and comparative examples are tested for their power under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius using a digital source meter device. The condition parameters not shown in the table are the same for both the embodiments and the comparative examples. For details, refer to the following table: Table 3:

[0088] It can be seen from Examples 13 to 18 and Comparative Examples 9 to 12 in Table 3 that when the area size of the semiconductor substrate 100 is 400 cm 2 , the ratio U / S between the voltage value of the reverse bias voltage in Examples 13 to 18 and the area size of the semiconductor substrate 100 is within the range of 54 mV / cm 2 ~68 mV / cm 2 , and the ratio U / S between the voltage value of the reverse bias voltage in Comparative Examples 9 to 12 and the area size of the semiconductor substrate 100 is outside the range of 0.048 W / cm 2~ 0.092 W / cm 2 . The open circuit voltage and conversion efficiency of the photovoltaic cells in Examples 13 to 18 are higher than those of Comparative Examples 9 to 12. Among them, compared with Comparative Examples 9 to 12, the conversion efficiency of the photovoltaic cells in Examples 13 to 18 is increased by at least 0.05%.

[0089] Thus, it can be seen that when the ratio U / S between the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 when the carrier excitation source irradiates the semiconductor substrate 100 and the area size of the semiconductor substrate 100 is within the range of 54 mV / cm 2 ~68 mV / cm 2 in the embodiments of the present application, the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0090] Further, the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the first time is greater than or equal to the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the subsequent time. Since a larger reverse bias voltage can enhance the carrier transport ability and contribute to the mutual diffusion between the finished electrode 230 and the doped layer 130 to form a good ohmic contact, the reverse bias voltage with a larger voltage value for the first or the first time can enhance the electric field strength, promote the accelerated movement of carriers between the finished electrode 230 and the semiconductor substrate 100, more effectively break the potential barrier at the interface, and promote the mutual diffusion between the finished electrode 230 and the doped layer 130, thereby forming a better-quality ohmic contact. The subsequent reverse bias voltage with a lower voltage value can not only finely adjust the formed ohmic contact, further optimize the stability of the contact interface, but also control the further growth of metal grains, and further optimize the conductivity and uniformity of the metallized contact between the finished electrode 230 and the semiconductor substrate 100.

[0091] In some embodiments, the ratio range of the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the first time to the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the subsequent time is 1 to 1.2. Optionally, the ratio of the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the first time to the voltage value of the reverse bias voltage applied to the semiconductor substrate 100 for the subsequent time can be 1.02, 1.05, 1.1 or 1.15.

[0092] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding embodiments and comparative examples are provided below for description. The number of times the carrier excitation source irradiates the semiconductor substrate 100 is two times, and the power of the two carrier excitation sources is 25W. The photovoltaic cells produced from the following embodiments and comparative examples are tested for their power under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius using a digital source meter device. The condition parameters not shown in the table are the same for the embodiments and comparative examples. Specifically, refer to the following table: Table 4:

[0093] It can be seen from Embodiments 19 to 24 and Comparative Examples 13 to 16 in Table 4 that when the area sizes of the semiconductor substrates 100 are all 400 cm 2When the voltage value of the first application of the reverse bias voltage is 25V in all cases, the ratio range between the voltage value of the first application of the reverse bias voltage to the semiconductor substrate 100 and the voltage value of the second application of the reverse bias voltage to the semiconductor substrate 100 in Examples 19 to 24 is 1 to 1.2. In Comparative Examples 13 to 16, the ratio between the voltage value of the first application of the reverse bias voltage to the semiconductor substrate 100 and the voltage value of the second application of the reverse bias voltage to the semiconductor substrate 100 is less than 1 or greater than 1.2. The open circuit voltage and conversion efficiency of the photovoltaic cells in Examples 19 to 24 are higher than those of Comparative Examples 13 to 16. Among them, compared with Comparative Examples 13 to 16, the conversion efficiency of the photovoltaic cells in Examples 19 to 24 is increased by at least 0.04%.

[0094] It can be seen that when the voltage value of the first application of the reverse bias voltage to the semiconductor substrate 100 is greater than or equal to the voltage value of the second application of the reverse bias voltage to the semiconductor substrate 100, and the ratio range between the two is 1 to 1.2, the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0095] Furthermore, while the carrier excitation source irradiates the semiconductor substrate 100 to sinter the initial electrode 220 or the finished electrode 230, a current is applied to the semiconductor substrate 100. When the carrier excitation source irradiates the semiconductor substrate 100, the region of the semiconductor substrate 100 not covered by the initial electrode 220 or the finished electrode 230 is irradiated by the carrier excitation source to excite carriers. By applying a current to the semiconductor substrate 100, the excited charge carriers are caused to move directionally, which is conducive to the excitation of electron-hole pairs, optimizing the electric field distribution of the semiconductor substrate 100, and promoting the formation of metal grains in the finished electrode 230, improving the metallization structure between the finished electrode 230 and the doped layer 130, thereby reducing the contact resistance between the finished electrode 230 and the doped layer 130, and further improving the photoelectric conversion efficiency of the photovoltaic cell.

[0096] Further, the current value applied to the semiconductor substrate 100 is proportional to the size area of the semiconductor substrate 100. In other words, the current value applied to the semiconductor substrate 100 increases proportionally as the area size of the semiconductor substrate 100 increases or decreases proportionally as the area size of the semiconductor substrate 100 decreases. The design in which the current value applied to the semiconductor substrate 100 is proportional to the size area of the semiconductor substrate 100 avoids local overheating of the semiconductor substrate 100 caused by a too large current value applied to the semiconductor substrate 100 with a small area size, resulting in excessive thermal stress and damage to the finished electrode 230 and the semiconductor substrate 100, or avoids poor metallization contact between the finished electrode 230 and the semiconductor substrate 100 and a large contact resistance due to a too small current value when the area size of the semiconductor substrate 100 is large, leading to a reduction in the photoelectric conversion efficiency of the photovoltaic cell.

[0097] In some embodiments, for the current value I of the current and the area size S of the semiconductor substrate 100, it satisfies 6 mA / cm 2 ≤ I / S ≤ 15 mA / cm 2 . Optionally, 8 mA / cm 2 ≤ I / S ≤ 14 mA / cm 2 , and the ratio I / S between the current value of the current and the area size of the semiconductor substrate 100 can be 8 mA / cm 2 , 10 mA / cm 2 , 12 mA / cm 2 or 14 mA / cm 2 .

[0098] In some embodiments, the range of the current value of the current applied to the semiconductor substrate 100 is 2 A to 7 A. Optionally, the current value of the current applied to the semiconductor substrate 100 can be 3 A, 4 A, 5 A, or 6 A.

[0099] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding examples and comparative examples are provided below. The number of executions of the carrier excitation source irradiating the semiconductor substrate 100 is two times, and the power of the two carrier excitation sources is the same. The photovoltaic cells obtained from the following examples and comparative examples are tested for their power under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius using a digital source meter device. The condition parameters not shown in the table are the same for both the examples and the comparative examples. Specifically, refer to the following table: Table 5:

[0100] It can be seen from Examples 25 to 30 and Comparative Examples 17 to 20 in Table 5 that when the area sizes of the semiconductor substrates 100 are all 400 cm 2In the case where the ratio I / S between the voltage value of the current applied to the semiconductor substrate 100 and the area size of the semiconductor substrate 100 in Examples 25 to 30 is within 6 mA / cm 2 ~15 mA / cm 2 and the ratio I / S between the voltage value of the current applied to the semiconductor substrate 100 and the area size of the semiconductor substrate 100 in Comparative Examples 17 to 20 is outside the range of 6 mA / cm 2 ~15 mA / cm 2 the open-circuit voltage and conversion efficiency of the photovoltaic cells in Examples 25 to 30 are both higher than those in Comparative Examples 17 to 20. Among them, the conversion efficiency of the photovoltaic cells in Examples 25 to 30 is increased by at least 0.05% compared with Comparative Examples 17 to 20.

[0101] It can be seen that when the ratio I / S between the voltage value of the current applied to the semiconductor substrate 100 and the area size of the semiconductor substrate 100 during the excitation of the semiconductor substrate 100 by the carrier excitation source is within the range of 6 mA / cm 2 ~15 mA / cm 2 the photoelectric conversion efficiency of the photovoltaic cells is improved.

[0102] Furthermore, the current value of the current applied to the semiconductor substrate 100 for the first time is greater than or equal to the current value of the current applied to the semiconductor substrate 100 for the second time. Applying a larger current value to the semiconductor substrate 100 for the first time or initially is conducive to exciting electron-hole pairs and optimizing the electric field distribution of the semiconductor substrate 100. Applying a subsequent smaller current value to the semiconductor substrate 100 finely adjusts the electric field distribution of the semiconductor substrate 100, improves the uniformity and stability of the metallized contact between the finished electrode 230 and the semiconductor substrate 100, and thus improves the reliability of the photovoltaic cell.

[0103] In some embodiments, the ratio range between the current value of the current applied to the semiconductor substrate 100 for the first time and the current value of the current applied to the semiconductor substrate 100 for the second time is 1 to 1.2. Optionally, the ratio between the current value of the current applied to the semiconductor substrate 100 for the first time and the current value of the current applied to the semiconductor substrate 100 for the second time can be 1.02, 1.05, 1.1, or 1.15.

[0104] To better illustrate the beneficial effects brought by the embodiments of the present application, the corresponding embodiments and comparative examples are provided below. The number of executions of the carrier excitation source irradiating the semiconductor substrate 100 is two times, and the power of the carrier excitation source is 25W both times. The photovoltaic cells obtained from the following embodiments and comparative examples are tested for their power under the conditions of AM1.5G simulated sunlight and 25 degrees Celsius using a digital source meter device. The condition parameters not shown in the table are the same for both the embodiments and the comparative examples. Please refer to the following table specifically: Table 6:

[0105] It can be seen from Examples 31 to 36 and Comparative Examples 21 to 24 in Table 6 that when the area size of the semiconductor substrate 100 is 400 cm 2 and the current value of the current applied for the first time is 4A, the ratio range between the current value of the current applied to the semiconductor substrate 100 for the first time and the current value of the current applied to the semiconductor substrate 100 for the second time in Examples 31 to 36 is 1 to 1.2. The ratio between the current value of the current applied to the semiconductor substrate 100 for the first time and the current value of the current applied to the semiconductor substrate 100 for the second time in Comparative Examples 21 to 24 is less than 1 or greater than 1.2. The open circuit voltage and conversion efficiency of the photovoltaic cells in Examples 31 to 36 are higher than those of Comparative Examples 21 to 24. Among them, compared with Comparative Examples 21 to 24, the conversion efficiency of the photovoltaic cells in Examples 31 to 36 is increased by at least 0.04%.

[0106] Thus, it can be seen that when the current value of the current applied to the semiconductor substrate 100 for the first time is greater than or equal to the current value of the current applied to the semiconductor substrate 100 for the second time, and the ratio range between the two is 1 to 1.2, the photoelectric conversion efficiency of the photovoltaic cell is improved.

[0107] In some embodiments, the length range of the finished electrode 230 is 5 cm to 100 cm. Optionally, the length of the finished electrode 230 can be selected as 10 cm, 20 cm, 30 cm, 40 cm, 50 cm, 60 cm, 70 cm, 80 cm, or 90 cm. In some embodiments, the width range of the finished electrode 230 is 2 μm to 60 μm. Optionally, the width of the finished electrode 230 can be selected as 10 μm, 20 μm, 30 μm, 40 μm, or 50 μm. During the formation of the finished electrode 230 with appropriate dimensions, it will not be melted due to its too small size or incompletely sintered due to its too large size.

[0108] In some embodiments, the carrier for the carrier excitation source to irradiate the semiconductor substrate 100 is a laser. The types of lasers can be selected from red light, infrared light, purple light, ultraviolet light, green light, blue light, or other lasers. These lasers not only have relatively high energy, but are also easy to obtain and have low costs.

[0109] It should be understood that the generation of a laser originates from the electrons in an atom being excited by external energy, transitioning from a low energy level to a high energy level, and then releasing photons when falling back from the high energy level to the low energy level. All these photons move synchronously with the same wavelength and phase, forming a laser. The device of the carrier excitation source, that is, the device for forming a laser, includes a pump source, a gain medium, and a resonator cavity. The pump source provides excitation energy to lift low-energy electrons to a high energy level; the gain medium is the medium for laser generation; the resonator cavity consists of two mirrors with specific geometric shapes and reflection characteristics, ensuring that photons are reflected multiple times within the cavity, thereby amplifying the laser.

[0110] It should be noted that the carrier laser for the carrier excitation source to irradiate the semiconductor substrate 100 multiple times can be one type or multiple types. Exemplarily, when the carrier laser for the carrier excitation source to irradiate the semiconductor substrate 100 multiple times is of multiple types, the carrier laser for the first carrier excitation source to irradiate is a blue light laser with relatively high energy, and the carrier laser for subsequent carrier excitation sources to irradiate is a red light laser with relatively low energy. Correspondingly, the device of the carrier excitation source for the carrier excitation source to irradiate the semiconductor substrate 100 multiple times can be one device or multiple devices. In this way, the carrier laser and device of the carrier excitation source can be flexibly selected according to actual needs, improving the process flexibility and adaptability of the preparation method of the photovoltaic cell of the present application.

[0111] According to some embodiments of the present application, on the other hand, the present application embodiments also provide a photovoltaic cell prepared by the preparation method of the photovoltaic cell provided by the foregoing embodiments. It should be noted that the same or corresponding parts as those in the foregoing embodiments will not be elaborated herein.

[0112] It should be noted that the photovoltaic cell can be a whole cell or a sliced cell. A sliced cell refers to a cell formed by cutting a complete whole cell through a cutting process.

[0113] In some embodiments, the photovoltaic cell includes, but is not limited to, one or any combination of battery chips such as PERC cells (Passivated Emitter Rear Cell), TOPCon cells (Tunnel Oxide Passivated Contact), BC cells (Back Contact), etc., which have metal electrodes and metallized contacts with semiconductor structures.

[0114] According to some embodiments of the present application, on the other hand, an embodiment of the present application further provides a photovoltaic module, which is used to convert the received light energy into electrical energy. It should be noted that the same or corresponding parts as the foregoing embodiments will not be described in detail here.

[0115] The photovoltaic module includes: a battery string, which is formed by connecting a plurality of photovoltaic cells formed by the preparation method of the solar cell provided in the foregoing embodiments, or formed by connecting a plurality of photovoltaic cells provided in the foregoing embodiments; an encapsulation film, which is used to cover the surface of the battery string; and a cover plate, which is used to cover the surface of the encapsulation film facing away from the battery string. The solar cells are electrically connected in the form of a whole piece or multiple sub-pieces to form a plurality of battery strings, and the plurality of battery strings are electrically connected in series and / or in parallel.

[0116] The material of the encapsulation film can be an organic encapsulation film such as ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastic body (POE) film or polyvinyl butyral (PVB) film.

[0117] The cover plate can be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. In some embodiments, the surface of the cover plate facing the film can be a concave-convex surface, so as to increase the utilization rate of incident light.

[0118] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present application, and in practical applications, various changes can be made in form and details 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. Therefore, the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A method for preparing a photovoltaic cell, characterized in that, Comprising: Providing a semiconductor substrate; Forming an initial electrode on the semiconductor substrate through a metallization heat treatment process; Radiating the semiconductor substrate with a carrier excitation source to sinter the initial electrode to form a finished electrode; Among them, the number of executions of irradiating the semiconductor substrate with the carrier excitation source is at least two times; for the area size S of the semiconductor substrate and the power value P of the carrier excitation source, it satisfies 0.048 W / cm 2 ≤ P / S ≤ 0.092 W / cm 2 .

2. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The power value of the carrier excitation source radiating the semiconductor substrate for the first time is greater than or equal to the power value of the carrier excitation source radiating the semiconductor substrate for the second time.

3. The method for preparing a photovoltaic cell according to claim 2, characterized in that, The ratio range of the power value of the carrier excitation source radiating the semiconductor substrate for the first time to the power value of the carrier excitation source radiating the semiconductor substrate for the second time is 1 to 1.

4.

4. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The power value range of the carrier excitation source is 10W to 50W.

5. The method for preparing a photovoltaic cell according to claim 1, characterized in that, While the carrier excitation source radiates the semiconductor substrate, a reverse bias voltage is applied to the semiconductor substrate.

6. The method for preparing a photovoltaic cell according to claim 5, characterized in that, The voltage value U of the reverse bias voltage and the area size S of the semiconductor substrate satisfy 54 mV / cm 2 ≤ U / S ≤ 68 mV / cm 2 .

7. The method for preparing a photovoltaic cell according to claim 6, characterized in that, The voltage value of the reverse bias voltage applied to the semiconductor substrate for the first time is greater than or equal to the voltage value of the reverse bias voltage applied to the semiconductor substrate for the second time.

8. The method for preparing a photovoltaic cell according to claim 7, characterized in that, The ratio range of the voltage value of the reverse bias voltage applied to the semiconductor substrate for the first time to the voltage value of the reverse bias voltage applied to the semiconductor substrate for the second time is 1 to 1.

2.

9. The method for preparing a photovoltaic cell according to claim 6 or 8, characterized in that, The voltage value of the reverse bias voltage is 10V to 30V.

10. The method for preparing a photovoltaic cell according to claim 1, characterized in that, While the carrier excitation source irradiates the semiconductor substrate, a current is applied to the semiconductor substrate.

11. The method for preparing a photovoltaic cell according to claim 10, characterized in that, The current value I of the said current satisfies 6 mA / cm 2 ≤ I / S ≤ 15 mA / cm 2 .

12. The method for preparing a photovoltaic cell according to claim 11, characterized in that, The current value of the current applied to the semiconductor substrate for the first time is greater than or equal to the current value of the current applied to the semiconductor substrate for the second time.

13. The method for preparing a photovoltaic cell according to claim 12, characterized in that, The ratio range of the current value of the current applied to the semiconductor substrate for the first time to the current value of the current applied to the semiconductor substrate for the second time is 1 to 1.

2.

14. The method for preparing a photovoltaic cell according to claim 11 or 13, characterized in that, The current value of the current is 2A to 7A.

15. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The area size of the semiconductor substrate is 100 cm 2 ~600 cm 2 .

16. The method for preparing a photovoltaic cell according to claim 1, characterized in that, The length of the finished electrode is 5cm to 100cm, and the width of the finished electrode is 2μm to 60μm.

17. The manufacturing method of the photovoltaic cell according to claim 1, wherein, The method for forming an initial electrode through a metallization heat treatment process includes: Performing screen printing treatment on the semiconductor substrate to form a paste grid line; Performing thermal sintering treatment on the paste grid line to form the initial electrode.

18. The manufacturing method of the photovoltaic cell according to claim 17, wherein, The sintering temperature of the thermal sintering treatment is 600°C to 880°C, and the sintering time of the thermal sintering treatment is 30s to 120s.

19. A photovoltaic cell, wherein, The photovoltaic cell is obtained by the preparation method of the photovoltaic cell according to any one of claims 1 to 18.

20. The photovoltaic cell according to claim 19, wherein, The photovoltaic cell includes at least one of a PERC cell, a TOPCon cell, or a BC cell.

21. A photovoltaic module, wherein, Comprising: A battery string formed by connecting a plurality of photovoltaic cells; An encapsulation adhesive film for covering the surface of the battery string; A cover plate for covering the surface of the encapsulation adhesive film facing away from the battery string; Wherein, the photovoltaic cell is obtained by the preparation method of the photovoltaic cell according to any one of claims 1 to 18, or the photovoltaic cell according to claim 19 or 20.

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