Battery piece manufacturing method and battery piece

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a manufacturing method of a battery piece and the battery piece, and the manufacturing method of the battery piece comprises the steps: providing a substrate; forming a first tunneling layer; forming a first doped conductive layer, wherein the first doped conductive layer covers the surface of the first tunneling layer; forming a second tunneling layer; forming a second initial doped conductive layer; laser processing is carried out, the laser processing comprises the steps that multiple lasers are adopted to irradiate the junction position of the first area and the second area, the multiple lasers arranged at the junction position of at least one first area and the second area comprise the first laser and the second laser, the first laser is close to the first area, and the second laser is close to the second area; and performing etching treatment, etching the second initial doped conductive layer irradiated by the second laser to remove part of the second initial doped conductive layer, taking the remaining second initial doped conductive layer on the side wall of the first region as a side wall connecting layer, and taking the non-etched second initial doped conductive layer as the second doped conductive layer. The hot spot phenomenon of the battery piece can be improved.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaics, and particularly to a method for manufacturing a solar cell and a solar cell. Background Art

[0002] Crystalline silicon solar cells have evolved from BSF, PERC to PERC+. Through continuous technological iteration and upgrade, the conversion efficiency of crystalline silicon solar cells has become higher and higher. Currently, the mass production efficiency of PERC+ reaches about 23.45%, which is close to its theoretical limit efficiency of 24.5%. The subsequent efficiency improvement is more difficult and the improvement space is limited. Nowadays, TOPcon cells, HJT cells, back-contact cells, etc. have become new development trends of crystalline silicon solar cells and are at the forefront of current international research and industrialization.

[0003] Among them, a back-contact cell is a type of crystalline silicon solar cell in which both the emitter electrode and the base electrode of the cell are located on the back of the cell. The back-contact cell has no metal grid electrode blocking on the front surface, increasing the light absorption efficiency and greatly enhancing the short-circuit current. At the same time, the back-contact cell uses amorphous silicon or microcrystalline silicon and their doping methods to passivate the cell surface, improving the open-circuit voltage. The above factors effectively increase the conversion efficiency of the back-contact cell, making the back-contact cell have good development prospects.

[0004] Currently, back-contact cells are troubled by the hot spot phenomenon. It is necessary to propose a method for manufacturing a solar cell to improve the hot spot phenomenon of the formed solar cell. Summary of the Invention

[0005] Embodiments of the present disclosure provide a method for manufacturing a solar cell and a solar cell, which can at least improve the hot spot phenomenon of the solar cell.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a method for manufacturing a battery cell, including: providing a substrate, the substrate including an opposite front surface and a back surface, and a first region and a second region arranged alternately on the back surface; forming a first tunneling layer, the first tunneling layer covering the surface of the first region; forming a first doped conductive layer, the first doped conductive layer covering the surface of the first tunneling layer, and the first doped conductive layer being doped with ions of a first doping type; forming a second tunneling layer, the second tunneling layer covering at least the surface of the second region and the sidewalls of the first region; forming a second initial doped conductive layer, the second initial doped conductive layer covering the surface of the second tunneling layer, and the second initial doped conductive layer being doped with ions of a second doping type; performing a laser treatment, the laser treatment including irradiating a position where the first region and the second region meet with a plurality of lasers, wherein, at least at a position where the first region and the second region meet, the plurality of lasers include a first laser and a second laser, the first laser being close to the first region, the second laser being close to the second region, and the energy density of the first laser being less than the energy density of the second laser; performing an etching treatment, etching the second initial doped conductive layer irradiated by the second laser to remove a part of the second initial doped conductive layer, and the remaining second initial doped conductive layer located on the sidewalls of the first region serves as a sidewall connection layer, and the unetched part serves as a second doped conductive layer.

[0007] In some embodiments, the process parameters of the laser treatment include: laser speed: 40 m / s to 80 m / s, the energy density of the first laser is 100 mj / cm 2 ~200 mj / cm 2 and the energy density of the second laser is 200 mj / cm 2 ~400 mj / cm 2 .

[0008] In some embodiments, a glass layer is further formed during the formation of the second initial doped conductive layer, the laser treatment irradiates the surface of the glass layer, the first laser forms a first concave structure on the surface of the glass layer, the second laser forms a second concave structure on the surface of the glass layer, and the arrangement density of the first concave structure is less than the arrangement density of the second concave structure.

[0009] In some embodiments, the etching treatment includes: a first etching step for etching the second initial doped conductive layer and the second tunneling layer to form the sidewall connection layer and the second doped conductive layer; a second etching step for etching the substrate to convert a part of the second region into a third region, the third region being located between the first region and the second region, and the distance between the third region and the front surface being less than the distance between the second region and the front surface.

[0010] In some embodiments, it further includes: performing a second laser treatment, and the second laser treatment irradiates the position irradiated by the second laser in the laser treatment.

[0011] According to some embodiments of the present disclosure, on the other hand, an embodiment of the present disclosure further provides a solar cell, including: a substrate, the substrate includes an opposite front surface and a back surface, the back surface includes an alternately arranged first region and a second region, and the distance between the first region and the front surface is greater than the distance between the second region and the front surface; a first tunneling layer, the first tunneling layer covers the surface of the first region; a first doped conductive layer, the first doped conductive layer covers the surface of the first tunneling layer, and the first doped conductive layer is doped with ions of a first doping type; a sidewall connection layer, the sidewall connection layer covers the sidewalls of the first region and the first doped conductive layer, and the sidewall connection layer is doped with ions of a second doping type; a second tunneling layer, the second tunneling layer covers the surface of the second region; a second doped conductive layer, the second doped conductive layer covers the surface of the second tunneling layer.

[0012] In some embodiments, the back surface further includes: a third region, the third region is located between the first region and the second region, and the distance between the third region and the front surface is less than the distance between the second region and the front surface, and the sidewall connection layer is opposite to a part of the third region and is spaced from the third region.

[0013] In some embodiments, the distance between the sidewall connection layer and the third region is 2 μm to 5 μm.

[0014] In some embodiments, the surface of the third region has a pyramid morphology.

[0015] In some embodiments, the first regions with the sidewall connection layer on the sidewalls account for 20% to 40% of all the first regions.

[0016] The technical solution provided by the embodiment of the present disclosure has at least the following advantages: after forming the second initial doped conductive layer, during the laser treatment, a first laser and a second laser are set. In this way, two different states of the second initial doped conductive layer will be formed during the irradiation. Based on this, during the subsequent etching treatment, a part of the second initial doped conductive layer irradiated by the first laser is not easily etched, and the second initial doped conductive layer irradiated by the second laser is more easily etched. In this way, a part of the second initial doped conductive layer can be retained on the sidewall of the first region as the sidewall connection layer. The sidewall connection layer is electrically connected to the first doped conductive layer to form a leakage channel, thereby improving the hot spot phenomenon of the solar cell. Description of the Drawings

[0017] One or more embodiments are exemplarily illustrated by pictures in the corresponding accompanying drawings. These exemplary illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the figures in the accompanying drawings do not constitute a scale limitation. To more clearly illustrate the technical solutions in the embodiments of the present disclosure or in the prior art, the accompanying drawings required for use in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0018] Figures 1 to 6 It is a schematic structural diagram corresponding to each step of a method for manufacturing a battery cell provided in an embodiment of the present disclosure. Detailed implementation manners

[0019] As can be seen from the background art, currently, when a battery cell is partially blocked or an abnormality occurs in the battery cell, it is very easy to generate a hot spot phenomenon on the battery cell. The hot spot phenomenon refers to the phenomenon that certain areas in the battery cell or module have a significantly higher temperature due to local overheating than other parts. This phenomenon is usually caused by uneven current distribution or too high local resistance, which may have a serious impact on the battery performance and life. Therefore, it is necessary to improve the hot spot phenomenon of the battery cell.

[0020] The embodiment of the present disclosure provides a method for manufacturing a battery cell. After forming the second initial doped conductive layer, during the laser treatment process, a first laser and a second laser are set. In this way, two different states of the second initial doped conductive layer will be formed during the irradiation process. Based on this, in the subsequent etching process, the part of the second initial doped conductive layer irradiated by the first laser is not easily etched, and the second initial doped conductive layer irradiated by the second laser is more easily etched. In this way, a part of the second initial doped conductive layer can be retained on the sidewall of the first region as a sidewall connection layer, and the sidewall connection layer is electrically connected to the first doped conductive layer to form a leakage channel, thereby improving the hot spot phenomenon of the battery cell.

[0021] In the description of the embodiments of the present disclosure, 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 and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined.

[0022] References to "embodiments" in this disclosure mean that the specific features, structures, or characteristics described in connection with the embodiments can be included in at least one embodiment of the present disclosure. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment each time, nor are they independent or alternative embodiments mutually exclusive of other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0023] In the description of the embodiments of the present disclosure, the term "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: there is A, there is both A and B, and there is B. In addition, the character " / " in this text generally indicates that the associated objects before and after are in an "or" relationship.

[0024] In the description of the embodiments of the present disclosure, the term "plural" refers to two or more (including two). Similarly, "multiple groups" refers to two or more groups (including two groups), and "multiple pieces" refers to two or more pieces (including two pieces).

[0025] In the description of the embodiments of the present disclosure, 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. It is only for the convenience of describing the embodiments of the present disclosure 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, and therefore should not be construed as a limitation on the embodiments of the present disclosure.

[0026] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "install", "connect", "couple", "fix", 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 internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0027] In the accompanying drawings corresponding to the embodiments of the present disclosure, for better understanding and convenience of description, the thickness and area of the layers are enlarged. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be a third component between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component "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.

[0028] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components may further be included. In addition, when components such as layers, films, regions, or plates are referred to as "on / lying on" another component, it can be "directly on" the other component (i.e., on the surface of the other component and there are no other components between them), or there can be another component between them. In addition, when components such as layers, films, regions, plates, etc. are "directly located on" another component, or when components such as layers, films, regions, plates, etc. are located on the surface of another component, it means that there are no other components between them.

[0029] The terms used in the description of the various embodiments herein are only for describing specific embodiments and are not intended to be limiting. As used in the description of the various embodiments and the appended claims, "the component" is also intended to include the plural form unless the context clearly indicates otherwise. Among them, the component includes components such as layers, films, regions, or plates.

[0030] The following will elaborate on the embodiments of the present disclosure in conjunction with the accompanying drawings. However, those of ordinary skill in the art can understand that in the embodiments of the present disclosure, many technical details are presented for the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed by the present disclosure can still be implemented.

[0031] Reference Figures 1 to 6 , Figures 1 to 6 is a schematic structural diagram corresponding to each step of a method for manufacturing a battery cell provided in an embodiment of the present disclosure.

[0032] In some embodiments, the method for manufacturing a battery cell may include: providing a substrate 100, the substrate 100 including an opposite front surface 110 and a back surface 120, and a first region 130 and a second region 140 arranged alternately on the back surface 120.

[0033] The manufacturing method of the battery cell may further include: forming a first tunneling layer 101, and the first tunneling layer 101 covers the surface of the first region 130.

[0034] The manufacturing method of the battery cell may further include: forming a first doped conductive layer 102, the first doped conductive layer 102 covers the surface of the first tunneling layer 101, and the first doped conductive layer 102 is doped with ions of a first doping type.

[0035] The manufacturing method of the battery cell may further include: forming a second tunneling layer 103, and the second tunneling layer 103 covers at least the surface of the second region 140 and the sidewalls of the first region 130.

[0036] The manufacturing method of the battery cell may further include: forming a second initial doped conductive layer 114, the second initial doped conductive layer 114 covers the surface of the second tunneling layer 103, and the second initial doped conductive layer 114 is doped with ions of a second doping type.

[0037] The manufacturing method of the battery cell may further include: performing a laser treatment, the laser treatment includes irradiating the position where the first region 130 and the second region 140 meet with multiple lasers. Among them, at least the multiple lasers arranged at one position where the first region 130 and the second region 140 meet include a first laser 105 and a second laser 106. The first laser 105 is close to the first region 130, the second laser 106 is close to the second region 140, and the energy density of the first laser is less than the energy density of the second laser.

[0038] The manufacturing method of the battery cell may further include: performing an etching treatment, etching the second initial doped conductive layer 114 irradiated by the second laser 106 to remove part of the second initial doped conductive layer 114. The remaining second initial doped conductive layer 114 located on the sidewalls of the first region 130 serves as a sidewall connection layer 200, and the unetched part serves as a second doped conductive layer 104.

[0039] The embodiment of the present disclosure provides a manufacturing method of a battery cell. After forming the second initial doped conductive layer 114, during the laser treatment process, the first laser 105 and the second laser 106 are set. In this way, two different states of the second initial doped conductive layer 114 will be formed during the irradiation process. Based on this, during the subsequent etching treatment, the part of the second initial doped conductive layer 114 irradiated by the first laser is not easily etched, and the second initial doped conductive layer 114 irradiated by the second laser 106 is more easily etched. In this way, part of the second initial doped conductive layer 114 can be retained on the sidewalls of the first region 130 to serve as a sidewall connection layer 200. The sidewall connection layer 200 is electrically connected to the first doped conductive layer 102 to form a leakage channel, thereby improving the hot spot phenomenon of the battery cell.

[0040] Reference Figure 1 AndFigure 2 , wherein, Figure 1 provides a substrate and forms a first tunneling layer and a first initially doped conductive layer, Figure 2 is to form a first doped conductive layer on the basis of Figure 1 .

[0041] The substrate 100 is used to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate 100, such as silicon, germanium, silicon-germanium, or silicon-on-insulator.

[0042] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. Among them, the elemental semiconductor material may be single crystal, polycrystalline, amorphous, or microcrystalline (the state with both single crystal and amorphous states is called microcrystalline). For example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. If the material of the substrate 100 is silicon, the material of the substrate 100 may include at least one of single crystal silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0043] The substrate 100 may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, and the N-type doping element may be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, and the P-type doping element may be any one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0044] If the solar cell is a single-sided cell, the front surface 110 of the substrate 100 serves as the light-receiving surface for receiving incident light, and the back surface 120 of the substrate 100 serves as the backlight surface.

[0045] The first region 130 may correspond to one of the N region and the P region in the cell, and the second region 140 may correspond to the other of the N region and the P region in the cell.

[0046] In some embodiments, the first tunneling layer 101 and the first initially doped conductive layer 112 may be formed on the back surface 120 by a whole-surface deposition method first, and then the first tunneling layer 101 and the first initially doped conductive layer 112 located on the surface of the second region 140 may be removed by a selective etching method, and the remaining first initially doped conductive layer 112 serves as the first doped conductive layer 102.

[0047] Among them, the method for forming the first initial doped conductive layer 112 may include: depositing a polysilicon layer on the surface of the first tunneling layer 101, and then converting the polysilicon layer into the first initial doped conductive layer 112 through a diffusion process. The diffusion process may be a boron diffusion process. During the process of converting the polysilicon layer into the first initial doped conductive layer 112, a first glass layer 108 will also be formed. Then, the first glass layer 108 located in the second region 140 is irradiated by a laser process to modify the first glass layer 108 located in the second region 140, reducing the etching difficulty of this part of the first glass layer 108. Then, through an etching process, the modified first glass layer 108, the first initial doped conductive layer 112, and the first tunneling layer 101 are removed, and the remaining first initial doped conductive layer 112 serves as the first doped conductive layer 102.

[0048] It can be understood that during the process of forming the first doped conductive layer 102, as the etching process progresses, a part of the second region 140 will also be etched, so that the thickness of the substrate 100 at the corresponding position of the second region 140 is reduced, exposing the sidewall of the first region 130.

[0049] Reference Figure 3 , a second tunneling layer and a second initial doped conductive layer are formed.

[0050] In some embodiments, the second tunneling layer 103 and the second initial doped conductive layer 114 may be formed by a blanket deposition method.

[0051] The method for forming the second initial doped conductive layer 114 may include: first forming a polysilicon layer, and then converting the polysilicon layer into the second initial doped conductive layer 114 through a diffusion process. The diffusion process may be a phosphorus diffusion process. During the process of converting the polysilicon layer into the second initial doped conductive layer 114, a second glass layer 109 will also be formed.

[0052] In some embodiments, the first glass layer 108 at the corresponding position of the first region 130 is not removed. Therefore, when the second tunneling layer 103 and the second initial doped conductive layer 114 are formed, they still cover the surface of the first glass layer 108. Moreover, since the sidewall of the first region 130 is exposed, the second tunneling layer 103 and the second initial doped conductive layer 114 also cover the sidewall of the first region 130.

[0053] Reference Figure 4 , laser treatment is performed.

[0054] It can be understood that during the laser treatment process, due to the limitations of the laser precision and spot size, it is impossible to well control the position irradiated by the laser treatment. That is to say, during the laser treatment process, it is impossible to ensure that the laser can accurately hit the required position. Moreover, since the spot has a certain size, it is difficult to control the starting point of the laser scanning to be the required starting point. For example, currently, the distance between the required starting point of the laser scanning and the first region 130 is 5 μm. During the actual control process, the distance is too short, resulting in inaccurate laser alignment. Moreover, the laser spot itself has a certain size, which will cause the starting point of the laser scanning not to be as expected. If the second laser 106 is directly used, the morphology formed after subsequent etching treatment will not meet the expectations. Therefore, in the present disclosure, two different lasers are provided at the positions where the leakage structure needs to be retained. The first laser 105 with relatively weak modification ability is used to ensure that the retained sidewall connection layer 200 has a certain size, so as to utilize the sidewall connection layer 200 to realize the leakage structure and improve the hot spot phenomenon of the formed battery cell.

[0055] It can be understood that during the laser treatment process, a single laser treatment will also provide multiple lasers. In other words, during a single laser treatment process, multiple lasers will exist simultaneously, thereby improving the efficiency of the laser treatment. Although the starting point of the laser scanning cannot be accurately positioned, the energy of each laser can be controlled. Therefore, the power of the laser close to the first region 130 is set low, so that even if there is a problem of inaccurate positioning, the second initial doped conductive layer 114 on the sidewall of the first region 130 will not be completely removed during the subsequent etching treatment process.

[0056] It can be understood that if the second laser 106 is fully used in the laser treatment, due to the problems of the laser treatment precision and the spot, the second initial doped conductive layer 114 on the sidewall of the first region 130 may be completely removed. Therefore, by providing the first laser 105, even if there are problems with the laser treatment precision and the spot, a part of the second initial doped conductive layer 114 on the sidewall of the first region 130 will still be retained, thereby forming the sidewall connection layer 200.

[0057] In some embodiments, it is also possible to control the spot of the laser close to the first region 130 to be larger than the spot of the laser close to the second region 140. Similarly, even if there are problems with the laser treatment precision and the spot, a part of the second initial doped conductive layer 114 on the sidewall of the first region 130 will still be retained, which can further facilitate the formation of the sidewall connection layer 200.

[0058] In some embodiments, the process parameters of the laser treatment include: laser speed: 40 m / s to 80 m / s, and the energy density of the first laser 105 is 100 mj / cm 2 ~200 mj / cm 2, the energy density of the second laser 106 is 200 mj / cm 2 ~400 mj / cm 2 .

[0059] Regarding the laser speed, if the laser speed is too slow, for example, less than 40 m / s, it may cause the substrate 100 to overheat and trigger lattice damage. If the laser speed is too fast, for example, greater than 80 m / s, it may result in poor laser effects. Regarding the energy density of the first laser 105, too high an energy density may affect the formation of the subsequent sidewall connection layer 200, causing the sidewall connection layer 200 to be etched incorrectly or resulting in a poor morphology of the sidewall connection layer 200. By setting the energy density of the first laser 105 to be greater than or equal to 100 mj / cm 2 , the top surface of the sidewall connection layer 200 can also be cleaned, and the contact resistance of the sidewall connection layer 200 can be stabilized. Regarding the energy density of the second laser 106, if the energy density is too low, for example, less than 200 mj / cm 2 , it may affect the etching of the second initial doped conductive layer 114, resulting in the second initial doped conductive layer 114 that needs to be etched not being etched cleanly. If the set energy density is too large, it may cause damage to the substrate 100.

[0060] In some embodiments, a glass layer is also formed during the formation of the second initial doped conductive layer 114. The laser treatment irradiates the surface of the glass layer. The first laser 105 forms a first concave structure on the surface of the glass layer, and the second laser 106 forms a second concave structure on the surface of the glass layer. The arrangement density of the first concave structure is less than that of the second concave structure. It can be understood that the greater the arrangement density of the second concave structure, the lower the difficulty of removing the glass layer, and the faster the etching speed of the glass layer during the etching process. Therefore, the first laser 105 is used to reduce the damage of the laser treatment to the glass layer at the corresponding position of the sidewall connection layer 200, thereby avoiding completely removing the second initial doped conductive layer 114 on the sidewall of the first region 130 during the etching process.

[0061] It can be understood that the glass layer is a protective layer during the etching process. During the etching process, if the glass layer is retained, then the second tunneling layer 103 and the second initial doped layer at the corresponding position of the glass layer will not be etched. Similarly, if the glass layer is retained, the second tunneling layer 103 and the second initial doped layer that need to be etched will not be etched. For example, the second tunneling layer 103 and the second initial doped layer in the first region 130 will not be etched. Therefore, setting the laser treatment to include both the first laser 105 and the second laser 106 can provide a process basis for retaining the sidewall connection layer 200 in the subsequent process and form the second doped conductive layer 104 at the same time.

[0062] In some embodiments, it further includes: performing a second laser treatment, and the second laser treatment irradiates the position irradiated by the second laser 106 in the laser treatment. Through the second laser treatment, the difficulty of removing the second initial doped conductive layer 114 in the etching process can be further reduced, and the time required for the etching process can be reduced.

[0063] In some embodiments, the energy density of the laser in the second laser treatment can also be higher than the energy density of the second laser 106. On the one hand, controlling the power of the second laser 106 can reduce the damage to the second initial doped conductive layer 114 caused by the laser treatment, and can further reduce the abnormalities caused by misalignment of the laser treatment. Then, it is adjusted through the second laser treatment, so as to further control the sidewall connection layer 200 formed subsequently to have the desired morphology through two laser treatments.

[0064] In some embodiments, the laser spot near the first region 130 is larger than the laser spot near the second region 140, and the second laser treatment can also irradiate on a part of the surface irradiated by the first laser 105. Similarly, the sidewall connection layer 200 formed subsequently is further controlled to have the desired morphology through two laser treatments.

[0065] Reference Figure 5 and Figure 6 , an etching process is performed.

[0066] In some embodiments, the etching process may include: a first etching step for etching the second initial doped conductive layer 114 and the second tunneling layer 103 to form the sidewall connection layer 200 and the second doped conductive layer 104; a second etching step for etching the substrate 100 to convert a part of the second region 140 into a third region 150, the third region 150 is located between the first region 130 and the second region 140, and the distance between the third region 150 and the front surface 110 is less than the distance between the second region 140 and the front surface 110.

[0067] Among them, the first etching step is used to etch the second initial doped conductive layer 114 and the second tunneling layer 103 to form the sidewall connection layer 200 and the second doped conductive layer 104 that are spaced apart from each other. Forming the sidewall connection layer 200 and the second doped conductive layer 104 in the same process step can reduce the process steps required to form the battery cell, thereby reducing the cost of the battery cell; the second etching step is used to etch a part of the substrate 100 to form the third region 150, and the formed third region 150 is spaced apart from the sidewall connection layer 200, so as to improve the isolation between the sidewall connection layer 200 and the second doped conductive layer 104, so as to ensure that during the etching of the second initial doped conductive layer 114 that needs to be etched, the second initial doped conductive layer 114 that needs to be etched is etched clean.

[0068] In some embodiments, during the second etching step, the first glass layer 108 and the second glass layer 109 that were not etched away in the first etching step are also removed.

[0069] Continue to refer to Figure 6 , and form a first electrode and a second electrode.

[0070] The first electrode 201 electrically connected to the first doped conductive layer 102 can be formed by screen printing. Similarly, the second electrode 202 electrically connected to the second doped conductive layer 104 can be formed by screen printing.

[0071] An embodiment of the present disclosure provides a method for manufacturing a solar cell. After forming the second initial doped conductive layer 114, during the laser treatment, the first laser 105 and the second laser 106 are set. In this way, two different states of the second initial doped conductive layer 114 will be formed during the irradiation process. Based on this, during the subsequent etching process, a part of the second initial doped conductive layer 114 irradiated by the first laser is not easily etched, and the second initial doped conductive layer 114 irradiated by the second laser 106 is more easily etched. In this way, a part of the second initial doped conductive layer 114 can be retained on the sidewall of the first region 130 as the sidewall connection layer 200. The sidewall connection layer 200 is electrically connected to the first doped conductive layer 102 to form a leakage channel, thereby improving the hot spot phenomenon of the solar cell.

[0072] Another embodiment of the present disclosure also provides a solar cell, which can be formed by the method for manufacturing a solar cell in some or all of the above embodiments. The solar cell provided in another embodiment of the present disclosure will be described below with reference to the accompanying drawings. It should be noted that for the same or corresponding parts in the foregoing embodiments, reference can be made to the corresponding descriptions in the foregoing embodiments, and details will not be repeated below.

[0073] Refer to Figure 6 , Figure 6 is a schematic structural diagram of a solar cell provided in an embodiment of the present disclosure.

[0074] In some embodiments, the solar cell may include: a substrate 100, the substrate 100 includes an opposite front surface 110 and a back surface 120, the back surface 120 includes an alternately arranged first region 130 and a second region 140, and the distance between the first region 130 and the front surface 110 is greater than the distance between the second region 140 and the front surface 110.

[0075] The solar cell may further include: a first tunneling layer 101, and the first tunneling layer 101 covers the surface of the first region 130.

[0076] The solar cell may further include: a first doped conductive layer 102 covering the surface of the first tunneling layer 101, and the first doped conductive layer 102 is doped with ions of a first doping type.

[0077] The solar cell may further include: a sidewall connection layer 200 covering the sidewalls of the first region 130 and the first doped conductive layer 102, and the sidewall connection layer 200 is doped with ions of a second doping type.

[0078] The solar cell may further include: a second tunneling layer 103 covering the surface of the second region 140.

[0079] The solar cell may further include: a second doped conductive layer 104 covering the surface of the second tunneling layer 103.

[0080] A leakage channel is constructed in the solar cell by using the sidewall connection layer 200, so that when the hot spot phenomenon occurs, the sidewall connection layer 200 is used for shunting to improve the hot spot phenomenon of the solar cell.

[0081] In some embodiments, the back surface 120 further includes: a third region 150 located between the first region 130 and the second region 140, and the distance between the third region 150 and the front surface 110 is less than the distance between the second region 140 and the front surface 110. A part of the sidewall connection layer 200 faces the third region 150 and is spaced from the third region 150. In other words, the thickness of the substrate 100 corresponding to the third region 150 is less than the thickness of the substrate 100 corresponding to the second region 140, so that the sidewall connection layer 200 is spaced from the substrate 100 corresponding to the third region 150, which can improve the insulation between the sidewall connection layer 200 and the second doped conductive layer 104.

[0082] In some embodiments, the distance between the sidewall connection layer 200 and the third region 150 is 2 μm to 5 μm, such as 3 μm, 3.5 μm or 4 μm, etc. If the distance between the sidewall connection layer 200 and the third region 150 is too small, on the one hand, it is not conducive to the formation of the process, and too small a distance makes the formation process difficult to control. On the other hand, too small a distance may result in electrical contact between the sidewall connection layer 200 and the second doped conductive layer 104, which may affect the photoelectric conversion efficiency of the solar cell; if the distance between the sidewall connection layer 200 and the third region 150 is too large, the effective carrier collection area will be reduced and the fill factor will be lowered.

[0083] In some embodiments, the surface of the third region 150 has a pyramid morphology, and the incident light on the back surface 120 is reflected back into the substrate 100 by using the pyramid morphology, thereby improving the light absorption ability of the substrate 100 and the photoelectric conversion efficiency of the solar cell.

[0084] In some embodiments, the first region 130 of the sidewall connection layer 200 existing on the sidewall is 20% to 40% of all the first regions 130. In other words, the coverage rate of the sidewall connection layer 200 is set to 20% to 40%. If the proportion of the first region 130 where the sidewall connection layer 200 exists on the sidewall is less than 20%, the effect of improving the hot spot phenomenon of the battery chip is not good. If the proportion of the first region 130 where the sidewall connection layer 200 exists on the sidewall is greater than 40%, excessive leakage will affect the collection of carriers in the battery chip and the photoelectric conversion efficiency of the carriers.

[0085] In some embodiments, the sidewall connection layer 200 is located on the sidewalls on opposite sides of the first region 130. That is to say, two spaced-apart sidewall connection layers 200 are formed on one first region 130, thereby further improving the hot spot phenomenon of the battery chip.

[0086] Those of ordinary skill in the art can understand that the above embodiments are specific embodiments for implementing the present disclosure. In practical applications, various changes can be made in form and details without departing from the spirit and scope of the embodiments of the present disclosure. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the embodiments of the present disclosure. Therefore, the protection scope of the embodiments of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A method for manufacturing a battery cell, characterized in that: include: Providing a substrate, the substrate comprising a front side and a back side opposite to each other, the back side being provided with first areas and second areas arranged alternately; forming a first tunneling layer, wherein the first tunneling layer covers a surface of the first region; forming a first doped conductive layer, wherein the first doped conductive layer covers a surface of the first tunneling layer and is doped with first doping type ions; forming a second tunneling layer, wherein the second tunneling layer at least covers the surface of the second region and the sidewall of the first region; forming a second initial doped conductive layer, wherein the second initial doped conductive layer covers the surface of the second tunneling layer, and the second initial doped conductive layer is doped with ions of a second doping type; Performing laser processing, the laser processing comprising using a plurality of lasers to irradiate a position where the first area and the second area intersect, wherein the plurality of lasers disposed at least at one position where the first area and the second area intersect comprise a first laser and a second laser, the first laser is close to the first area, the second laser is close to the second area, and the energy density of the first laser is less than the energy density of the second laser; An etching process is performed to etch the second initial doped conductive layer irradiated by the second laser to remove a portion of the second initial doped conductive layer, and the remaining second initial doped conductive layer located on the side wall of the first region serves as a sidewall connecting layer, and the unetched portion serves as a second doped conductive layer.

2. The method for manufacturing a battery cell according to claim 1, characterized in that: The process parameters of the laser treatment include: laser speed: 40m / s to 80m / s, energy density of the first laser is 100mj / cm 2 ~200mj / cm 2 The energy density of the second laser is 200mj / cm 2 ~400mj / cm 2 .

3. The method for manufacturing a battery cell according to claim 1, characterized in that: A glass layer is also formed during the process of forming the second initial doped conductive layer. The laser processing irradiates the surface of the glass layer. The first laser forms a first recessed structure on the surface of the glass layer. The second laser forms a second recessed structure on the surface of the glass layer. The arrangement density of the first recessed structure is less than the arrangement density of the second recessed structure.

4. The method for manufacturing a battery cell according to claim 1, characterized in that: The etching process comprises: A first etching step, wherein the first etching step is used to etch the second initial doped conductive layer and the second tunneling layer to form the sidewall connecting layer and the second doped conductive layer; A second etching step is performed to etch the substrate to convert part of the second area into a third area, wherein the third area is located between the first area and the second area, and the distance between the third area and the front side is smaller than the distance between the second area and the front side.

5. The method for manufacturing a battery cell according to claim 1, characterized in that: Also includes: A second laser process is performed that irradiates the position irradiated by the second laser in the laser process.

6. A battery cell, characterized in that: include: A substrate, the substrate comprising a front side and a back side opposite to each other, the back side comprising first areas and second areas arranged alternately, the distance between the first areas and the front side being greater than the distance between the second areas and the front side; a first tunneling layer, wherein the first tunneling layer covers a surface of the first region; a first doped conductive layer, wherein the first doped conductive layer covers a surface of the first tunneling layer and is doped with first doping type ions; a sidewall connection layer, the sidewall connection layer covering the first region and the sidewalls of the first doped conductive layer, the sidewall connection layer being doped with ions of a second doping type; a second tunneling layer, wherein the second tunneling layer covers a surface of the second region; A second doped conductive layer covers a surface of the second tunneling layer.

7. The battery cell according to claim 6, characterized in that: The back side also includes: a third area, the third area is located between the first area and the second area, and the distance between the third area and the front side is smaller than the distance between the second area and the front side, and the side wall connection layer portion is directly opposite to the third area and is spaced from the third area.

8. The battery cell according to claim 7, characterized in that: The distance between the sidewall connection layer and the third region is 2 μm to 5 μm.

9. The battery cell according to claim 7, characterized in that: The surface of the third region is in a pyramid shape.

10. The battery cell according to claim 6, characterized in that: The first region where the sidewall connecting layer exists on the sidewall accounts for 20% to 40% of all the first regions.

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