Back contact cell and method of manufacturing the same, stacked cell, photovoltaic module

Abstract

The embodiment of the present disclosure relates to the field of photovoltaics, and provides a back contact cell, a manufacturing method thereof, a laminated cell and a photovoltaic module. The back contact cell comprises a substrate having a first surface side and a second surface side opposite to each other along a first direction, and a first region and a second region arranged alternately along a second direction on the second surface side; a tunneling layer located at least on the first region; a first doped semiconductor layer located on a side of the tunneling layer away from the substrate; a first transparent conductive layer located on a side of the first doped semiconductor layer away from the substrate, and a surface of the first transparent conductive layer away from the substrate has a plurality of light-trapping particles; an amorphous silicon layer located at least on the second region; a second doped semiconductor layer located on a side of the amorphous silicon layer away from the substrate; and a second transparent conductive layer located on a side of the second doped semiconductor layer away from the substrate, and the first transparent conductive layer and the second transparent conductive layer have a spacing therebetween, which is at least beneficial to improving the light-trapping effect and the carrier collection efficiency of the back contact cell.

Description

Technical Field

[0001] This disclosure relates to the photovoltaic field, and in particular to a back contact battery and its manufacturing method, a tandem battery, and a photovoltaic module. Background Technology

[0002] With the gradual depletion of fossil fuels, photovoltaic (PV) cells are becoming increasingly widely used as a new energy alternative. A PV cell is a device that converts solar energy into electrical energy. PV cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient use of electrical energy. To further reduce the shading of the front side of PV cells by the grid lines, research on BC (Back Contact) cells is becoming increasingly in-depth.

[0003] However, to improve the photoelectric conversion efficiency of BC cells, different types of passivation contact structures are designed in different regions on the back of the BC cell. These different passivation contact structures in different regions exhibit varying light absorption and utilization, and the subsequent electrodes also show differences in the collection efficiency of charge carriers accumulated in different passivation contact structures. Therefore, further research on BC cells is needed to compensate for the impact of these differences on their photoelectric conversion efficiency. Summary of the Invention

[0004] This disclosure provides a back contact battery and its manufacturing method, a tandem battery, and a photovoltaic module, which at least help improve the light trapping effect and carrier collection efficiency of the back contact battery.

[0005] According to some embodiments of this disclosure, one aspect of this disclosure provides a back contact battery, comprising: a substrate having a first surface side and a second surface side opposite to each other along a first direction, the second surface side including a first region and a second region alternately arranged along a second direction; a tunneling layer, at least located on the first region; a first doped semiconductor layer located on the side of the tunneling layer away from the substrate; a first transparent conductive layer located on the side of the first doped semiconductor layer away from the substrate, the surface of the first transparent conductive layer away from the substrate having a plurality of light-trapping particles; an amorphous silicon layer, at least located on the second region; a second doped semiconductor layer located on the side of the amorphous silicon layer away from the substrate; a second transparent conductive layer located on the side of the second doped semiconductor layer away from the substrate, and a gap being present between the second transparent conductive layer and the first transparent conductive layer.

[0006] In some embodiments, the size of the light-trapping particles is 1 μm to 4 μm.

[0007] In some embodiments, the distribution density of the light-trapping particles is 2.5 × 10⁻⁶. 6 pcs / cm 2 ~4.5×106 pcs / cm 2 .

[0008] In some embodiments, the first region is a polished surface and the second region is a velvety surface.

[0009] In some embodiments, the material of the light-trapping particles is the same as the material of the first transparent conductive layer; or, the material of the light-trapping particles includes at least one of silicon oxide, titanium oxide, zinc oxide, and silver nanoparticles, and the material of the first transparent conductive layer includes at least one of tin-doped indium oxide, tungsten-doped indium oxide, cesium-doped indium oxide, tin oxide, cadmium-doped zinc oxide, aluminum-doped zinc oxide, and aluminum zinc oxide.

[0010] In some embodiments, the back contact battery further includes a protective layer located on the side of the first transparent conductive layer away from the substrate.

[0011] In some embodiments, along the first direction, the thickness of the first transparent conductive layer is greater than the thickness of the second transparent conductive layer.

[0012] In some embodiments, both the first doped semiconductor layer and the substrate are doped with a first doping element, and the second doped semiconductor layer is doped with a second doping element, wherein the first doping element and the second doping element have different doping types; and / or, the material of the first doped semiconductor layer includes doped polycrystalline silicon, and the material of the second doped semiconductor layer includes doped amorphous silicon.

[0013] According to some embodiments of this disclosure, another aspect of this disclosure provides a method for manufacturing a back contact battery, comprising: providing a substrate having a first surface side and a second surface side opposite to each other along a first direction, the second surface side including a first region and a second region alternately arranged along a second direction; forming a tunneling layer and a first doped semiconductor layer on at least the first region, the first doped semiconductor layer being located on the side of the tunneling layer away from the substrate; forming an amorphous silicon layer and a second doped semiconductor layer on at least the second region, the second doped semiconductor layer being located on the side of the tunneling layer away from the substrate; forming a first transparent conductive layer and a second transparent conductive layer; wherein the first transparent conductive layer is located on the side of the first doped semiconductor layer away from the substrate, the surface of the first transparent conductive layer away from the substrate having a plurality of light-trapping particles; the second transparent conductive layer is located on the side of the second doped semiconductor layer away from the substrate, and there is a gap between the second transparent conductive layer and the first transparent conductive layer.

[0014] In some embodiments, the step of forming the first transparent conductive layer and the second transparent conductive layer includes: forming an initial transparent conductive layer located both on the side of the first doped semiconductor layer away from the first region and on the side of the second doped semiconductor layer away from the second region; performing a grooving process on the initial transparent conductive layer such that there is a gap between the initial transparent conductive layer located on the first region and the initial transparent conductive layer located on the second region; and performing laser processing on the initial transparent conductive layer located on the first region to form the light-trapping particles on the surface of the initial transparent conductive layer located on the first region away from the substrate.

[0015] In some embodiments, the wavelength of the laser used in the laser processing is 355nm~532nm.

[0016] In some embodiments, the step of forming the first transparent conductive layer includes: forming an initial first transparent conductive layer on the side of the first doped semiconductor layer away from the first region; and etching the surface of the initial first transparent conductive layer away from the substrate to form the first transparent conductive layer having the light-trapping particles.

[0017] In some embodiments, the step of forming the first transparent conductive layer includes: forming an initial first transparent conductive layer on the side of the first doped semiconductor layer away from the first region; forming the light-trapping particles on the surface of the initial first transparent conductive layer away from the substrate; wherein the light-trapping particles are located on the surface of the initial first transparent conductive layer away from the substrate, or a portion of the light-trapping particles is embedded in the initial first transparent conductive layer; the light-trapping particles and the initial first transparent conductive layer together constitute the first transparent conductive layer.

[0018] According to some embodiments of this disclosure, another aspect of this disclosure also provides a stacked battery, comprising: a bottom battery, which is a back contact battery as described in any of the preceding claims, or a back contact battery formed by a manufacturing method of a back contact battery as described in any of the preceding claims; and a top battery, which is located on one side of the bottom battery.

[0019] According to some embodiments of this disclosure, another aspect of this disclosure provides a photovoltaic module, comprising: a battery string, which is formed by electrically connecting a plurality of back-contact batteries as described in any of the above claims, or formed by electrically connecting a plurality of back-contact batteries formed by a manufacturing method of a back-contact battery as described in any of the above claims, or formed by electrically connecting a plurality of stacked batteries as described in the above claims; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string.

[0020] The technical solutions provided in this disclosure have at least the following advantages:

[0021] Based on the design of two passivation contact structures with significantly different materials on the first and second regions of the second surface, the surface of the first transparent conductive layer in the first region, away from the substrate, is designed with multiple light-trapping particles. On one hand, these particles enhance the light-trapping effect of the first transparent conductive layer, allowing more light to reach the first region for absorption and utilization, thereby generating more photogenerated carriers. On the other hand, they increase the contact area between the subsequent electrode and the first transparent conductive layer, reducing the contact resistance and improving the carrier collection efficiency of the electrode. This multi-faceted collaboration helps to compensate for the differences in photoelectric conversion efficiency between the corresponding local back contact cells in the first and second regions, thus improving the overall photoelectric conversion efficiency of the back contact cell.

[0022] In addition, the light-trapping particles help to improve the adhesion between the subsequent electrode and the first transparent conductive layer, thereby increasing the connection strength between the two and improving the structural stability of the back contact battery. Attached Figure Description

[0023] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0025] Figure 2 A scanning electron microscope image of the first transparent conductive layer in a back contact battery provided in an embodiment of this disclosure;

[0026] Figure 3 This is another partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0027] Figure 4 This is another partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0028] Figure 5 This is another partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0029] Figure 6 A partial cross-sectional view of a method for manufacturing a back contact battery according to another embodiment of this disclosure after the formation of an initial transparent conductive layer;

[0030] Figure 7 This is a partial cross-sectional view of a back contact battery manufacturing method according to another embodiment of the present disclosure after grooving.

[0031] Figure 8 A partial cross-sectional view of a method for manufacturing a back contact battery according to another embodiment of this disclosure after the formation of an initial first transparent conductive layer;

[0032] Figure 9 A partial cross-sectional schematic diagram of a stacked battery provided in yet another embodiment of this disclosure;

[0033] Figure 10 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure;

[0034] Figure 11 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0035] Explanation of reference numerals in the attached figures:

[0036] 100, Substrate; 110, First surface side; 120, Second surface side; 1201, First region; 1202, Second region; 101, Tunneling layer; 102, First doped semiconductor layer; 103, First transparent conductive layer; 113, Light-trapping particles; 123, Initial first transparent conductive layer; 104, Amorphous silicon layer; 105, Second doped semiconductor layer; 106, Second transparent conductive layer; 136, Initial transparent conductive layer; 107, Protective layer; 117, Front passivation layer; 108, Bottom cell; 118, First electrode; 128, Second electrode; 109, Top cell; 40, Back contact cell; 41, Encapsulating film; 42, Cover plate; 43, Conductive strip. Detailed Implementation

[0037] As can be seen from the background technology, the photoelectric conversion efficiency of BC cells needs to be further improved.

[0038] This disclosure provides a back-contact battery and its manufacturing method, a tandem battery, and a photovoltaic module. In the back-contact battery, based on two passivation contact structures with significantly different materials designed on the first and second regions on the second surface side, a first transparent conductive layer on the first region has multiple light-trapping particles on its surface away from the substrate. On one hand, these particles enhance the light-trapping effect of the first transparent conductive layer, allowing more light to reach and be absorbed in the first region, thereby generating more photogenerated carriers. On the other hand, they increase the contact area between the subsequent electrode and the first transparent conductive layer, reducing the contact resistance and improving the carrier collection efficiency of the electrode. This multi-faceted collaboration helps compensate for the difference in photoelectric conversion efficiency between the corresponding local back-contact batteries in the first and second regions, thereby improving the overall photoelectric conversion efficiency of the back-contact battery. Furthermore, the light-trapping particles enhance the adhesion between the subsequent electrode and the first transparent conductive layer, increasing the connection strength and improving the structural stability of the back-contact battery.

[0039] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

[0040] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this disclosure. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0041] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0042] In the description of embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0043] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0044] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0045] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

[0046] In the description of embodiments of this disclosure, when a component "includes" another component, other components are not excluded unless otherwise stated, and may be further included. Furthermore, when a component such as a layer, film, region, or plate is referred to as being "on / located" on another component, it can be "directly" on the other component (i.e., located on the surface of the other component with no other components between them), or another component may be present therein. Additionally, when a component such as a layer, film, region, or plate is "directly located" on another component, or when a component such as a layer, film, region, or plate is located on the surface of another component, it indicates that no other components are located therein.

[0047] The terminology used in the description of the various embodiments herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in the description and claims of the various embodiments described, the term "component" is also intended to include the plural form unless the context clearly indicates otherwise. Components include layers, films, regions, or plates, etc.

[0048] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the embodiments. However, the technical solutions claimed in the embodiments of this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

[0049] This disclosure provides an embodiment of a back contact battery, which will be described in detail below with reference to the accompanying drawings.

[0050] refer to Figure 1 The back contact battery includes: a substrate 100 having a first surface side 110 and a second surface side 120 opposite each other along a first direction X, the second surface side 120 including a first region 1201 and a second region 1202 alternately arranged along a second direction Y; a tunneling layer 101 located at least on the first region 1201; a first doped semiconductor layer 102 located on the side of the tunneling layer 101 away from the substrate 100; a first transparent conductive layer 103 located on the side of the first doped semiconductor layer 102 away from the substrate 100, the surface of the first transparent conductive layer 103 away from the substrate 100 having a plurality of light-trapping particles 113; an amorphous silicon layer 104 located at least on the second region 1202; a second doped semiconductor layer 105 located on the side of the amorphous silicon layer 104 away from the substrate 100; and a second transparent conductive layer 106 located on the side of the second doped semiconductor layer 105 away from the substrate 100, with a gap between the second transparent conductive layer 106 and the first transparent conductive layer 103.

[0051] It should be noted that, Figure 1 This is a partial cross-sectional schematic diagram of a back contact battery provided in an embodiment of the present disclosure; Figure 2 This is a scanning electron microscope image of the first transparent conductive layer in a back contact battery provided in an embodiment of the present disclosure.

[0052] also, Figure 1The diagram uses only black dots as an example to illustrate the multiple light-trapping particles 113 on the surface of the first transparent conductive layer 103 away from the substrate 100. In practical applications, the light-trapping particles can be spherical particles or particles with other irregular shapes. In other words, the surface morphology of the light-trapping particles has a certain degree of randomness. The cross-sectional shape of the light-trapping particles along any cross-section can be approximately circular, elliptical, N-shaped, or an irregular shape, where N is a positive integer greater than or equal to 3.

[0053] The arrows are clearly illustrated in the first transparent conductive layer 103. Figure 2 The red arrows in the image indicate the multiple light-trapping particles 113 on the surface of the first transparent conductive layer 103 away from the substrate 100. Figure 2 The whitish particles shown are light-trapping particles 113.

[0054] It is worth noting that the first passivation contact structure located on the first region 1201 includes a tunneling layer 101 and a first doped semiconductor layer 102, and the second passivation contact structure located at least on the second region 1202 includes an amorphous silicon layer 104 and a second doped semiconductor layer 105. Thus, the back contact cell is a HIBC cell, and the HTBC cell is a heterojunction tunnel oxide passivated contact hybrid passivated back contact photovoltaic cell (abbreviated as HTBC).

[0055] Among them, the first region 1201 and the second region 1202 of the second surface side 120 are designed with two passivation contact structures with large material differences, which makes the light absorption and utilization rate of the first region 1201 and the second region 1202 different. Moreover, in general, the passivation effect of the amorphous silicon layer 104 on the second region 1202 is better than that of the tunneling layer 101 on the first region 1201. The differences in various aspects make the photoelectric conversion efficiency of the corresponding local back contact cells of the first region 1201 and the second region 1202 different. Based on this, the surface of the first transparent conductive layer 103 located on the first region 1201 away from the substrate 100 is designed with multiple light-trapping particles 113. On the one hand, the light-trapping particles 113 help to enhance the light-trapping effect of the first transparent conductive layer 103, allowing more light to reach the first region 1201 for absorption and utilization, thereby generating more photogenerated carriers. On the other hand, the light-trapping particles 113 help to increase the contact area between the subsequent electrode and the first transparent conductive layer 103, thereby reducing the contact resistance between them and improving the collection efficiency of the charge carriers by the electrode. In this way, the cooperation of multiple aspects helps to compensate for the difference in photoelectric conversion efficiency between the local back contact cells corresponding to the first region 1201 and the second region 1202, thereby improving the overall photoelectric conversion efficiency of the back contact cell.

[0056] In addition, the light-trapping particles 113 help to improve the adhesion between the subsequent electrode and the first transparent conductive layer 103, thereby improving the connection strength between the two and improving the structural stability of the back contact battery.

[0057] It should be noted that, for ease of description of the arrangement of the first and second passivation contact structures on the substrate 100, the second surface side 120 of the substrate 100 is divided into a first region 1201 and a second region 1202. In some cases, the first region 1201 can be considered as the area where the first passivation contact structure is located on the second surface side 120 of the substrate 100; the second region 1202 can be considered as the area where the second passivation contact structure is located on the second surface side 120 of the substrate 100. It is worth noting that, depending on the choice of fabrication process, the second passivation contact structure can be as follows: Figure 1 As shown, the second passivation contact structure is located not only on the second region 1202, but also on a portion of the first region 1201 near the second region 1202. In practical applications, the second passivation contact structure can also be located only on the second region.

[0058] In other words, in some cases, the first region 1201 can be regarded as: the region in the substrate 100 that is directly opposite to the first doped semiconductor layer 102 along the first direction X, or it can be understood as the region where the orthogonal projection of the first doped semiconductor layer 102 is located on the substrate 100; the second region 1202 can be regarded as: at least a portion of the region in the substrate 100 that is directly opposite to the second doped semiconductor layer 105 along the first direction X, or it can be understood as at least a portion of the region where the orthogonal projection of the second doped semiconductor layer 105 is located on the substrate 100.

[0059] It should be noted that, Figure 1 The diagram only shows three first zones 1201 and two second zones 1202. In practical applications, the first and second zones can be arranged alternately along the second direction as follows: the second surface side includes multiple first zones and multiple second zones, with one first zone interspersed between two adjacent second zones, and one second zone interspersed between two adjacent first zones.

[0060] also, Figure 1 The example shown is that there is no gap between the first zone 1201 and the second zone 1202. In actual applications, the first zone and the second zone can also have a gap.

[0061] The following will describe in more detail an embodiment of the back contact battery provided in this disclosure with reference to the accompanying drawings.

[0062] In some embodiments, reference Figure 1 The substrate 100 is used to receive incident light and generate photogenerated carriers.

[0063] In some examples, the material of the substrate 100 can be an elemental semiconductor material. Optionally, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material can be monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing monocrystalline and amorphous states is called microcrystalline). For example, silicon can be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0064] In other examples, the material of substrate 100 may be a compound semiconductor material. Optionally, common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, or copper indium selenide; in still other examples, substrate 100 may also be a sapphire substrate, a silicon-on-insulator substrate, or a germanium-on-insulator substrate.

[0065] In some embodiments, reference Figure 1 Both the first doped semiconductor layer 102 and the substrate 100 are doped with a first doping element, and the second doped semiconductor layer 105 is doped with a second doping element. The doping types of the first doping element and the second doping element are different.

[0066] In some cases, the first doping element is an N-type doping element and the second doping element is a P-type doping element. In this case, the substrate 100 can be an N-type substrate, the first doped semiconductor layer 102 is an N-type doped semiconductor layer, and the second doped semiconductor layer 105 is a P-type doped semiconductor layer. In other cases, the first doping element is a P-type doping element and the second doping element is an N-type doping element. In this case, the substrate 100 can be a P-type substrate, the first doped semiconductor layer 102 is a P-type doped semiconductor layer, and the second doped semiconductor layer 105 is an N-type doped semiconductor layer.

[0067] In some examples, the N-type dopant can be at least 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, which can be at least one of group III elements such as boron (B), aluminum (Al), gallium (Ga), or gallium (In).

[0068] In some cases, the material of the first doped semiconductor layer 102 may include doped polycrystalline silicon, and the material of the second doped semiconductor layer 105 may include doped amorphous silicon.

[0069] In some cases, the material of the tunneling layer 101 can be silicon oxide.

[0070] In some embodiments, reference Figure 1 or Figure 2 The size of the light-trapping particles 113 can be from 1μm to 4μm, for example, it can be 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, 2μm, 2.1μm, 2.2μm, 2.3μm, 2.4μm, 2.5μm, 2.6μm, 2.7μm, 2.8μm, 2.9μm, 3μm, 3.1μm, 3.2μm, 3.3μm, 3.4μm, 3.5μm, 3.6μm, 3.7μm, 3.8μm or 3.9μm, etc.

[0071] It is worth noting that, on the one hand, considering that the wavelength range of light that the substrate 100 in the back contact battery can absorb and utilize is generally 300nm~1200nm, designing the size of the light-trapping particles 113 to be at the micrometer level rather than the nanometer level is beneficial to improving the matching degree between the size of the light-trapping particles 113 and the wavelength of light that the substrate 100 can absorb and utilize, thereby improving the scattering effect of the light-trapping particles 113 on the light that the substrate 100 can absorb and utilize, and thus improving the light-trapping effect of the first transparent conductive layer 103. It is also worth noting that if the size of the light-trapping particles is less than 100nm, it can be considered that the size of the light-trapping particles is at the nanometer level, and the gain of nanometer-sized light-trapping particles on the light-trapping effect of the substrate is not significant or even non-existent.

[0072] On the other hand, designing the size of the light-trapping particles 113 to be at the micrometer level rather than the nanometer level is beneficial to reducing the specific surface area of ​​the first transparent conductive layer 103, that is, reducing the ratio of the surface area to the volume of the first transparent conductive layer 103. This can reduce the parasitic absorption of light, especially short-wavelength light, by the first transparent conductive layer 103, thereby avoiding the temperature rise of the first transparent conductive layer 103.

[0073] On the other hand, compared with nanoscale light-trapping particles, micron-scale light-trapping particles 113 are less prone to agglomeration, which helps to improve the uniformity of the distribution of light-trapping particles 113 in the first transparent conductive layer 103 and improve the structural stability of the first transparent conductive layer 103, thereby helping to make each region in the first transparent conductive layer 103 have a basically consistent light-trapping effect.

[0074] In other embodiments, the size of the light-trapping particles 113 may also be 4 μm to 10 μm.

[0075] It is worth noting that if the size of the light-trapping particles 113 is greater than 10 μm, the number of light-trapping particles 113 that can be arranged per unit area in the first transparent conductive layer 103 will be significantly reduced, which is not conducive to improving the light-trapping effect of the first transparent conductive layer 103. Based on this, designing the size of the light-trapping particles 113 to be 1 μm to 10 μm is beneficial to ensure that the number of light-trapping particles 113 that can be arranged per unit area in the first transparent conductive layer 103 is moderate, so as to ensure that the first transparent conductive layer 103 has a better light-trapping effect. Among them, designing the size of the light-trapping particles 113 to be 1 μm to 4 μm results in a better light-trapping effect of the first transparent conductive layer 103.

[0076] Furthermore, the size of the light-trapping particles 113 may vary depending on the process used to prepare them. The preparation process of the light-trapping particles 113 will be described similarly later.

[0077] It should be noted that the size of the light-trapping particle 113 can be any one of the diameter of the light-trapping particle 113 or the length, width, or diagonal length of the orthographic projection pattern of the light-trapping particle 113 on the substrate 100. In practical applications, the orthographic projection pattern of the light-trapping particle on the substrate can also be an irregular polygon. In this case, the length, width, or diagonal length of the orthographic projection pattern of the light-trapping particle on the substrate is not absolute, but is artificially defined to characterize the size of the light-trapping particle. For example, when the orthographic projection pattern of the light-trapping particle on the substrate is an irregular quadrilateral, the length of the orthographic projection pattern of the light-trapping particle on the substrate can be defined as the side length of the longest side of the irregular quadrilateral, the width of the orthographic projection pattern of the light-trapping particle on the substrate can be defined as the side length of the shortest side of the irregular quadrilateral, and the diagonal length of the orthographic projection pattern of the light-trapping particle on the substrate can be defined as the side length of the longest diagonal of the irregular quadrilateral. It should be understood that the above is only an exemplary description, and in practice, it can be flexibly defined according to actual needs.

[0078] In addition, the orthographic projection pattern of the light-trapping particles on the substrate can be an irregular quadrilateral, or other irregular polygons, circles, or irregular shapes that are approximately circular. In this case, the size of the light-trapping particles is selected by choosing multiple regions with different specific areas in the light-trapping particles. These specific areas can be flexibly defined according to actual needs, and then the average value of the length, width, diagonal, or diameter of multiple regions with different specific areas is calculated.

[0079] In some embodiments, reference Figure 1 or Figure 2 The distribution density of light-trapping particles 113 can be 2.5 × 10⁻⁶. 6 pcs / cm 2 ~4.5×10 6 pcs / cm 2 .

[0080] In some embodiments, reference Figure 1 The first zone 1201 can be a polished surface, and the second zone 1202 can be a velvety surface.

[0081] It is worth noting that, due to the different materials of the tunneling layer 101 on the first region 1201 and the amorphous silicon layer 104 on the second region 1202, the passivation effect of the tunneling layer 101 on the first region 1201 differs from that of the amorphous silicon layer 104 on the second region 1202. Therefore, designing the first region 1201 as a polished surface is beneficial for improving the uniformity of the tunneling layer 101 on the first region 1201, ensuring that the thickness of each region in the tunneling layer 101 is not significantly different. This improves the overall passivation effect of the tunneling layer 101 on the first region 1201, compensating for the difference between the passivation effect of the tunneling layer 101 on the first region 1201 and the passivation effect of the amorphous silicon layer 104 on the second region 1202. Furthermore, it can also improve the uniformity of the first doped semiconductor layer 102 and its passivation effect on the second region 1202. In addition, designing the second region 1202 to have a textured surface is beneficial to improve the light trapping effect of the second region 1202 while using the amorphous silicon layer 104 to generate a good passivation effect on the second region 1202, so as to further increase the density of photogenerated carriers.

[0082] In some embodiments, reference Figure 1 The material of the light-trapping particles 113 can be the same as the material of the first transparent conductive layer 103.

[0083] In some cases, the material of the light-trapping particles 113 can be integrally formed with the first transparent conductive layer 103, which is beneficial to improving the efficiency of preparing the light-trapping particles 113 and the first transparent conductive layer 103 and reducing their preparation cost.

[0084] In some cases, the materials of the light-trapping particles 113 and the first transparent conductive layer 103 can be at least one of tin-doped indium oxide, tungsten-doped indium oxide, cesium-doped indium oxide, tin oxide, cadmium-doped zinc oxide, aluminum-doped zinc oxide, and aluminum zinc oxide.

[0085] In other embodiments, reference is made to... Figure 1 The material of the light-trapping particles 113 may include at least one of silicon oxide, titanium oxide, zinc oxide, and silver nanoparticles, and the material of the first transparent conductive layer 103 may include at least one of tin-doped indium oxide, tungsten-doped indium oxide, cesium-doped indium oxide, tin oxide, cisium-doped zinc oxide, aluminum-doped zinc oxide, and aluminum zinc oxide. In other words, the material of the light-trapping particles 113 is different from the material of the first transparent conductive layer 103.

[0086] In the various embodiments described above, the material of the second transparent conductive layer 106 can be the same as that of the first transparent conductive layer 103. This allows the second transparent conductive layer 106 to be fabricated during the fabrication of the first transparent conductive layer 103, which improves the efficiency of fabricating both the first and second transparent conductive layers 103 and reduces their fabrication cost.

[0087] In some cases, the material of the second transparent conductive layer 106 may also be at least one of tin-doped indium oxide, tungsten-doped indium oxide, cesium-doped indium oxide, tin oxide, cisium-doped zinc oxide, aluminum-doped zinc oxide, and zinc aluminum oxide.

[0088] In some embodiments, reference Figure 3 , Figure 3 This is a partial cross-sectional view of another back-contact battery provided in an embodiment of the present disclosure. The back-contact battery may further include a protective layer 107 located on the side of the first transparent conductive layer 103 away from the substrate 100. It is worth noting that, on the one hand, the protective layer 107 helps to protect the surface of the light-trapping particles 113, preventing the light-trapping particles 113 from being oxidized or damaged and thus failing, thereby ensuring that the light-trapping particles 113 have a good light-trapping effect; on the other hand, the protective layer 107 can also limit the light-trapping particles 113 to improve the structural stability of the first transparent conductive layer 103; furthermore, the protective layer 107 can also passivate or reduce reflection to further improve the utilization rate of light in the first region 1201 and the density of photogenerated carriers.

[0089] It is worth noting that the protective layer 107 is not only located in the gaps between the different light-trapping particles 113, but also on the surface of the light-trapping particles 113. Furthermore, Figure 3 Taking the example where the protective layer 107 is located only on the side of the first transparent conductive layer 103 away from the substrate 100, in actual applications, the protective layer can also be located on the side of the second transparent conductive layer away from the substrate.

[0090] In some cases, when the light-trapping particles 113 are silver nanoparticles, the protective layer 107 can prevent the phase-separated silver nanostructures from agglomerating and failing, thereby improving the uniformity of the distribution of the light-trapping particles 113 within the first transparent conductive layer 103.

[0091] In some cases, the material of the protective layer 107 may include at least one of silicon oxide, silicon nitride, silicon oxynitride, or aluminum oxide.

[0092] In some embodiments, reference Figure 1 or Figure 3 Along the first direction X, the thickness of the first transparent conductive layer 103 can be greater than the thickness of the second transparent conductive layer 106.

[0093] In some cases, the photogenerated carriers generated in the substrate 100 are divided into electrons and holes. The first transparent conductive layer 103 is doped with an N-type dopant and is used to transport electrons generated in the substrate 100; the first transparent conductive layer 103 can be considered an electron transport layer. The second transparent conductive layer 106 is doped with a P-type dopant and is used to transport holes generated in the substrate 100; the second transparent conductive layer 106 can be considered a hole transport layer. Generally, the mobility of electrons is significantly higher than that of holes.

[0094] Based on this, the thickness of the first transparent conductive layer 103 is designed to be greater than the thickness of the second transparent conductive layer 106. On the one hand, designing a thinner second transparent conductive layer 106 helps to reduce the length of the hole transport path along the first direction X in the second transparent conductive layer 106, thereby reducing the resistance loss of holes in the second transparent conductive layer 106, which helps to improve the fill factor of the back contact battery and reduce the series resistance of the back contact battery. On the other hand, designing a thicker first transparent conductive layer 103 helps to reduce the resistance of electrons transporting laterally in the first transparent conductive layer 103, that is, to reduce the resistance of electrons transporting along the direction perpendicular to the first direction X, so as to ensure efficient collection of electrons.

[0095] In some embodiments, reference Figure 4 , Figure 4 This is a partial cross-sectional view of another back-contact battery provided in an embodiment of the present disclosure. The back-contact battery may further include: a first electrode 118 located on a first region 1201 and in contact with a first transparent conductive layer 103; and a second electrode 128 located on a second region 1202 and in contact with a second transparent conductive layer 106. It is worth noting that the first electrode 118 may not be in contact with the first doped semiconductor layer 102, and charge carriers in the first doped semiconductor layer 102 are transported to the first electrode 118 via the first transparent conductive layer 103; the second electrode 128 may not be in contact with the second doped semiconductor layer 105, and charge carriers in the second doped semiconductor layer 105 are transported to the second electrode 128 via the second transparent conductive layer 106.

[0096] In some embodiments, reference Figure 5 , Figure 5 This is a partial cross-sectional view of a back contact battery provided in an embodiment of the present disclosure. The back contact battery may further include: a front passivation layer 117 located on the first surface side 110 of the substrate 100.

[0097] In some cases, continue to refer to Figure 5The front passivation layer 117 can be a stacked structure. For example, the front passivation layer 117 can be a combined film of an aluminum oxide layer and a silicon oxynitride layer, with the aluminum oxide layer closer to the first surface side 110. In other cases, the front passivation layer can also be a single film structure. For example, the front passivation layer can be a silicon nitride layer.

[0098] In some embodiments, reference Figure 1 , Figures 3 to 5 With the first surface side 110 as the reference plane, the second region 1202 is closer to the first surface side 110 along the first direction X compared to the first region 1201. Herein, the first direction X is the thickness direction of the substrate 100.

[0099] In other words, compared to the first region 1201, the second region 1202 is recessed into the substrate 100, such that the surface of most areas of the second passivation contact structure away from the substrate 100 is lower than the surface of the first passivation contact structure away from the substrate 100. The first passivation contact structure located on the first region 1201 includes a tunneling layer 101 and a first doped semiconductor layer 102, and the second passivation contact structure located at least on the second region 1202 includes an amorphous silicon layer 104 and a second doped semiconductor layer 105. This is beneficial for further improving the light-trapping effect of the second region 1202.

[0100] In summary, based on the design of two passivation contact structures with significantly different materials on the first region 1201 and the second region 1202 of the second surface side 120, the surface of the first transparent conductive layer 103 on the first region 1201 away from the substrate 100 is designed to have multiple light-trapping particles 113. On the one hand, the light-trapping particles 113 help to enhance the light-trapping effect of the first transparent conductive layer 103, allowing more light to reach the first region 1201 for absorption and utilization, thereby generating more photogenerated carriers. On the other hand, the light-trapping particles 113 help to increase the contact area between the subsequent electrode and the first transparent conductive layer 103, thereby reducing the contact resistance between them and improving the collection efficiency of the charge carriers by the electrode. Thus, the multi-faceted collaboration helps to compensate for the difference in photoelectric conversion efficiency between the corresponding local back contact cells in the first region 1201 and the second region 1202, thereby improving the overall photoelectric conversion efficiency of the back contact cell.

[0101] In addition, the light-trapping particles 113 help to improve the adhesion between the subsequent electrode and the first transparent conductive layer 103, thereby improving the connection strength between the two and improving the structural stability of the back contact battery.

[0102] Another embodiment of this disclosure provides a method for manufacturing a back contact battery, used to prepare the back contact battery provided in the foregoing embodiments. The manufacturing method of the back contact battery provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be repeated here.

[0103] Reference Figures 1 to 5 A method for manufacturing a back contact battery includes: providing a substrate 100, the substrate 100 having a first surface side 110 and a second surface side 120 opposite each other along a first direction X, the second surface side 120 including a first region 1201 and a second region 1202 alternately arranged along a second direction Y; forming at least a tunneling layer 101 and a first doped semiconductor layer 102 on the first region 1201, the first doped semiconductor layer 102 being located on the side of the tunneling layer 101 away from the substrate 100; and forming at least an amorphous silicon layer 104 and a second doped semiconductor layer 105 on the second region 1202. 5. The second doped semiconductor layer 105 is located on the side of the tunneling layer 101 away from the substrate 100; a first transparent conductive layer 103 and a second transparent conductive layer 106 are formed; wherein, the first transparent conductive layer 103 is located on the side of the first doped semiconductor layer 102 away from the substrate 100, and the surface of the first transparent conductive layer 103 away from the substrate 100 has a plurality of light-trapping particles 113; the second transparent conductive layer 106 is located on the side of the second doped semiconductor layer 105 away from the substrate 100, and there is a gap between the second transparent conductive layer 106 and the first transparent conductive layer 103.

[0104] It is worth noting that the first transparent conductive layer 103, which has multiple light-trapping particles 113 on its surface away from the substrate 100, helps to compensate for the difference in photoelectric conversion efficiency between the local back contact cells corresponding to the first region 1201 and the second region 1202, thereby improving the overall photoelectric conversion efficiency of the back contact cell. Furthermore, the light-trapping particles 113 help to improve the adhesion between the subsequent electrode and the first transparent conductive layer 103, thereby increasing the connection strength between them and improving the structural stability of the back contact cell.

[0105] It should be noted that in the manufacturing method of the back contact battery provided in another embodiment of this disclosure, the steps of forming the tunneling layer 101, the first doped semiconductor layer 102, the amorphous silicon layer 104 and the second doped semiconductor layer 105 are not limited in much. The process methods that can be used to prepare the tunneling layer 101, the first doped semiconductor layer 102, the amorphous silicon layer 104 and the second doped semiconductor layer 105 in HTBC batteries are all applicable to the manufacturing method of the back contact battery provided in another embodiment of this disclosure, and are not listed one by one in another embodiment of this disclosure.

[0106] The following describes in detail the methods for forming the first transparent conductive layer 103 and the second transparent conductive layer 106 through multiple embodiments.

[0107] In some embodiments, in conjunction with reference Figure 6 , Figure 7 and Figure 1 The steps of forming the first transparent conductive layer 103 and the second transparent conductive layer 106 may include: referring to Figure 6 An initial transparent conductive layer 136 is formed, which is located both on the side of the first doped semiconductor layer 102 away from the first region 1201 and on the side of the second doped semiconductor layer 105 away from the second region 1202; in conjunction with reference Figure 6 and Figure 7 The initial transparent conductive layer 136 is slotted to create a gap between the initial transparent conductive layer 136 located in the first region 1201 and the initial transparent conductive layer 136 located in the second region 1202; in conjunction with the reference Figure 7 and Figure 1 The initial transparent conductive layer 136 located on the first region 1201 is laser-processed to form light-trapping particles 113 on the surface of the initial transparent conductive layer 136 located on the first region 1201 away from the substrate 100.

[0108] in, Figure 6 A partial cross-sectional view of a method for manufacturing a back contact battery according to another embodiment of this disclosure after the formation of an initial transparent conductive layer; Figure 7 This is a partial cross-sectional view of a back contact battery manufacturing method according to another embodiment of the present disclosure, after a grooving process.

[0109] It is worth noting that, in conjunction with references Figure 6 and Figure 7 After the initial transparent conductive layer 136 is grooved, the remaining initial transparent conductive layer 136 located on the second region 1202 becomes the second transparent conductive layer 106. Subsequently, after laser processing of the initial transparent conductive layer 136 located on the first region 1201, a first transparent conductive layer 103 with light-trapping particles 113 is formed on the first region 1201. Thus, the second transparent conductive layer 106 can be formed during the fabrication of the first transparent conductive layer 103, which simplifies the process steps for fabricating the back contact battery, improves the efficiency of fabricating the first and second transparent conductive layers 103, and reduces the fabrication cost.

[0110] In some cases, laser patterning or ink etching processes can be used to create grooves in the initial transparent conductive layer 136.

[0111] In some cases, a laser scanning process can be used to laser-process the initial transparent conductive layer 136 located on the first region 1201 to form light-trapping particles 113 on the surface of the initial transparent conductive layer 136 located on the first region 1201 away from the substrate 100. It is worth noting that the laser in the laser scanning process not only affects the initial transparent conductive layer 136 located on the first region 1201, but also affects the first doped semiconductor layer 102 located below the initial transparent conductive layer 136, thereby causing elements in the first doped semiconductor layer 102 to diffuse into the initial transparent conductive layer 136, so as to conformally form the light-trapping particles 113 with the initial transparent conductive layer 136.

[0112] In some cases, the wavelength of the laser used in laser processing can be 355nm~532nm, for example, it can be 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 510nm, 520nm or 530nm, etc.

[0113] It is worth noting that if the wavelength of the laser used in the laser processing is less than 355 nm, the laser's penetration is weak, and its impact on the first doped semiconductor layer 102 located below the initial transparent conductive layer 136 is small, which is not conducive to forming a suitable number of light-trapping particles 113. If the wavelength of the laser used in the laser processing is greater than 532 nm, the laser's penetration is strong, which can easily cause laser damage to the initial transparent conductive layer 136 and the first doped semiconductor layer 102. Therefore, designing the laser used in the laser processing to have a wavelength of 355 nm to 532 nm is beneficial for forming a suitable number of light-trapping particles 113 in the initial transparent conductive layer 136 and for avoiding laser damage to the initial transparent conductive layer 136 and the first doped semiconductor layer 102.

[0114] In other embodiments, in conjunction with reference to Figure 8 and Figure 1 , Figure 8 This is a partial cross-sectional view of a method for manufacturing a back contact battery according to another embodiment of the present disclosure after forming an initial first transparent conductive layer. The step of forming the first transparent conductive layer 103 may include: forming an initial first transparent conductive layer 123 on the side of the first doped semiconductor layer 102 away from the first region 1201; and etching the surface of the initial first transparent conductive layer 123 away from the substrate 100 to form a first transparent conductive layer 103 having light-trapping particles 113.

[0115] In some cases, in conjunction with references Figure 8 and Figure 1The steps of forming the initial first transparent conductive layer 123 and etching the surface of the initial first transparent conductive layer 123 away from the substrate 100 can both be performed before forming the second transparent conductive layer 106. In other words, the second transparent conductive layer 106 is formed after the first transparent conductive layer 103 with light-trapping particles 113 is formed. It should be noted that in practical applications, the steps of forming the second transparent conductive layer and the initial first transparent conductive layer can be performed simultaneously. For example, the initial transparent conductive layer is formed, then the initial transparent conductive layer used as the second transparent conductive layer is covered with a mask layer, the initial transparent conductive layer used as the first transparent conductive layer is etched, and the initial transparent conductive layer located between the first and second transparent conductive layers is removed.

[0116] In some cases, the step of etching the surface of the initial first transparent conductive layer 123 away from the substrate 100 includes: spraying an etching solution onto the surface of the initial first transparent conductive layer 123 away from the substrate 100, and using the etching solution to perform local etching on the surface of the initial first transparent conductive layer 123 away from the substrate 100, thereby forming light-trapping particles 113.

[0117] In some examples, the etching solution may be an acidic solution comprising hydrogen chloride and / or ammonium fluoride, wherein the concentration of hydrogen chloride or ammonium fluoride in the etching solution may be 1% to 10%, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%, etc.

[0118] In some examples, the etching temperature for etching the surface of the initial first transparent conductive layer 123 away from the substrate 100 can be 25°C to 150°C, for example, it can be 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C or 140°C, etc.

[0119] In some examples, the etching time for etching the surface of the initial first transparent conductive layer 123 away from the substrate 100 can be 30s to 180s, for example, it can be 40s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, 130s, 140s, 150s, 160s or 170s, etc.

[0120] In yet other embodiments, in conjunction with reference to the reference Figure 8 and Figure 1The step of forming the first transparent conductive layer 103 includes: forming an initial first transparent conductive layer 123 on the side of the first doped semiconductor layer 102 away from the first region 1201; forming light-trapping particles 113 on the surface of the initial first transparent conductive layer 123 away from the substrate 100; wherein the light-trapping particles 113 are located on the surface of the initial first transparent conductive layer 123 away from the substrate 100, or a portion of the light-trapping particles 113 is embedded in the initial first transparent conductive layer 123; the light-trapping particles 113 and the initial first transparent conductive layer 123 together constitute the first transparent conductive layer 103.

[0121] It is worth noting that light-trapping particles 113 can be formed on the surface of the initial first transparent conductive layer 123 away from the substrate 100 using a coating process or a deposition process. Among them, the coating process will exert a certain pressure on the initial first transparent conductive layer 123, which may cause some areas of the light-trapping particles 113 to embed into the initial first transparent conductive layer 123.

[0122] Another embodiment of this disclosure provides a tandem battery, which includes the photovoltaic cell provided in the foregoing embodiments, or a photovoltaic cell formed by the manufacturing method of the photovoltaic cell provided in the foregoing embodiments. The tandem battery provided in another embodiment of this disclosure will be described in detail below with reference to the accompanying drawings. It should be noted that parts that are the same as or corresponding to those in the foregoing embodiments will not be repeated here.

[0123] refer to Figure 9 , Figure 9 This is a partial cross-sectional schematic diagram of a tandem solar cell provided in another embodiment of the present disclosure. The tandem solar cell includes: a bottom cell 108, which is a photovoltaic cell provided in the foregoing embodiment, or a photovoltaic cell formed by the manufacturing method of the photovoltaic cell provided in the foregoing embodiment; and a top cell 109, which is located on one side of the bottom cell 108.

[0124] In some embodiments, the top cell 109 may be one of perovskite solar cells, donor-acceptor cells, cadmium telluride (CdTe) photovoltaic cells, copper indium gallium selenide (CIGS) photovoltaic cells, or gallium arsenide (GaAs) photovoltaic cells.

[0125] In some embodiments, the top cell 109 may include: a first transport layer, a perovskite substrate, a second transport layer, a transparent conductive layer, and an antireflection layer stacked together. The first transport layer is directly opposite the bottom cell 108.

[0126] In some examples, the first transport layer can be either an electron transport layer or a hole transport layer, and the second transport layer can be either an electron transport layer or a hole transport layer.

[0127] In some embodiments, the bandgap width of the top cell 109 is wider than that of the bottom cell 108. Therefore, stacking the top cell 109 on top of the bottom cell 108 can give the tandem cell a wider spectral response range, thereby maximizing the utilization of solar energy and improving the efficiency of the photovoltaic cell.

[0128] In some embodiments, the back-contact stacked battery may further include an intermediate connecting layer (not shown in the figure), which is connected between the bottom battery 108 and the top battery 109.

[0129] In some cases, the intermediate connecting layer is typically a tunnel junction or a very thin metal or transparent electrode composite layer. Optionally, the intermediate connecting layer can be a transparent conductive oxide, which has good optoelectronic properties, high photon transmittance, and high conductivity, thereby enabling the top cell 109 and the bottom cell 108 to maintain good ohmic contact.

[0130] In other cases, the back grid, back main grid, front grid, and front main grid of the photovoltaic cell serving as the bottom cell 108 can also serve as an intermediate connection layer for electrical connection with the top cell 109.

[0131] Another embodiment of this disclosure provides a photovoltaic module, which includes multiple photovoltaic cells as provided in the foregoing embodiments, or photovoltaic cells formed by the manufacturing method of multiple photovoltaic cells as provided in the foregoing embodiments, or multiple stacked cells as provided in the foregoing embodiments connected together. The photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same as or corresponding to the foregoing embodiments can be referred to the corresponding descriptions of the foregoing embodiments, and will not be repeated below.

[0132] Reference Figure 10 , Figure 11 as well as Figures 1 to 9 The photovoltaic module includes: a battery string, which is formed by electrically connecting multiple back contact batteries 40 provided in the foregoing embodiments, or formed by electrically connecting back contact batteries 40 formed by the manufacturing method of photovoltaic cells provided in the foregoing embodiments, or formed by electrically connecting multiple stacked batteries provided in the foregoing embodiments; an encapsulating film 41 for covering the surface of the battery string; and a cover plate 42 for covering the surface of the encapsulating film 41 away from the battery string.

[0133] in, Figure 10 A partial three-dimensional schematic diagram of a cell string in a photovoltaic module provided in another embodiment of the present disclosure; Figure 11 This is a partial cross-sectional schematic diagram of a photovoltaic module provided in another embodiment of the present disclosure.

[0134] In some embodiments, the back contact battery 40 is electrically connected in the form of a single sheet or multiple segments to form multiple battery strings, and the multiple battery strings are electrically connected in series and / or parallel. The back contact battery 40 can be a single sheet of battery or a slice of battery, where a slice of battery refers to a battery formed by cutting a single sheet of battery.

[0135] In some embodiments, reference Figure 10 or Figure 11 Multiple back-contact batteries 40 can be electrically connected to each other via conductive strips 43. Figure 10 and Figure 11 This diagram only illustrates the positional relationship between two back contact batteries 40. In practical applications, the grid lines of multiple adjacent back contact batteries can also be located on different sides, and the conductive strip connects the different sides of two adjacent back contact batteries.

[0136] In some embodiments, the encapsulating film 41 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the back contact battery 40, and the second encapsulating layer covers the other of the front or back sides of the back contact battery 40. Specifically, at least one of the first encapsulating layer or the second encapsulating layer may be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulating layer or the second encapsulating layer may also be an EP film, EPE film, or PVP film. Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film; EPE film refers to a co-extruded film formed by sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be prepared by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

[0137] In some cases, the first encapsulation layer and the second encapsulation layer still have a boundary line before lamination. After lamination, the photovoltaic module will no longer have the concept of a first encapsulation layer and a second encapsulation layer. That is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 41.

[0138] In some embodiments, the cover plate 42 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate 42 facing the encapsulating film 41 can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 42 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0139] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.

Claims

1. A back-contact battery, characterized in that, include: A substrate having a first surface side and a second surface side opposite each other along a first direction, the second surface side including a first region and a second region alternately arranged along a second direction; A tunnel layer, at least located on the first region; The first doped semiconductor layer is located on the side of the tunneling layer away from the substrate; A first transparent conductive layer is located on the side of the first doped semiconductor layer away from the substrate, and the surface of the first transparent conductive layer away from the substrate has a plurality of light-trapping particles. An amorphous silicon layer is located at least on the second region; The second doped semiconductor layer is located on the side of the amorphous silicon layer away from the substrate; A second transparent conductive layer is located on the side of the second doped semiconductor layer away from the substrate, and there is a gap between the second transparent conductive layer and the first transparent conductive layer.

2. The back contact battery according to claim 1, characterized in that, The size of the light-trapping particles is 1μm~4μm.

3. The back contact battery according to claim 1, characterized in that, The distribution density of the light-trapping particles is 2.5 × 10⁻⁶. 6 pcs / cm 2 ~4.5×10 6 pcs / cm 2 .

4. The back contact battery according to claim 1, characterized in that, The first area is a polished surface, and the second area is a velvety surface.

5. The back contact battery according to claim 1, characterized in that, The material of the light-trapping particles is the same as the material of the first transparent conductive layer; or, the material of the light-trapping particles includes at least one of silicon oxide, titanium oxide, zinc oxide, and silver nanoparticles, and the material of the first transparent conductive layer includes at least one of tin-doped indium oxide, tungsten-doped indium oxide, cesium-doped indium oxide, tin oxide, cisium-doped zinc oxide, aluminum-doped zinc oxide, and aluminum zinc oxide.

6. The back contact battery according to claim 1 or 5, characterized in that, Also includes: A protective layer is located on the side of the first transparent conductive layer away from the substrate.

7. The back contact battery according to claim 1, characterized in that, Along the first direction, the thickness of the first transparent conductive layer is greater than the thickness of the second transparent conductive layer.

8. The back contact battery according to claim 1, characterized in that, Both the first doped semiconductor layer and the substrate are doped with a first doping element, and the second doped semiconductor layer is doped with a second doping element. The first doping element and the second doping element have different doping types. And / or, the material of the first doped semiconductor layer includes doped polycrystalline silicon, and the material of the second doped semiconductor layer includes doped amorphous silicon.

9. A method for manufacturing a back-contact battery, characterized in that, include: A substrate is provided, the substrate having a first surface side and a second surface side opposite to each other along a first direction, the second surface side including a first region and a second region alternately arranged along a second direction; A tunneling layer and a first doped semiconductor layer are formed at least on the first region, wherein the first doped semiconductor layer is located on the side of the tunneling layer away from the substrate; An amorphous silicon layer and a second doped semiconductor layer are formed at least on the second region, the second doped semiconductor layer being located on the side of the tunneling layer away from the substrate; Forming a first transparent conductive layer and a second transparent conductive layer; The first transparent conductive layer is located on the side of the first doped semiconductor layer away from the substrate, and the surface of the first transparent conductive layer away from the substrate has a plurality of light-trapping particles. The second transparent conductive layer is located on the side of the second doped semiconductor layer away from the substrate, and there is a gap between the second transparent conductive layer and the first transparent conductive layer.

10. The method for manufacturing a back contact battery according to claim 9, characterized in that, The steps of forming the first transparent conductive layer and the second transparent conductive layer include: An initial transparent conductive layer is formed, wherein the initial transparent conductive layer is located both on the side of the first doped semiconductor layer away from the first region and on the side of the second doped semiconductor layer away from the second region; The initial transparent conductive layer is slotted to create a gap between the initial transparent conductive layer located in the first region and the initial transparent conductive layer located in the second region. The initial transparent conductive layer located in the first region is laser-processed to form the light-trapping particles on the surface of the initial transparent conductive layer located in the first region away from the substrate.

11. The method for manufacturing a back contact battery according to claim 10, characterized in that, The wavelength of the laser used in the laser processing is 355nm~532nm.

12. The method for manufacturing a back contact battery according to claim 9, characterized in that, The steps for forming the first transparent conductive layer include: An initial first transparent conductive layer is formed on the side of the first doped semiconductor layer away from the first region; The surface of the initial first transparent conductive layer away from the substrate is etched to form the first transparent conductive layer having the light-trapping particles.

13. The method for manufacturing a back contact battery according to claim 9, characterized in that, The steps for forming the first transparent conductive layer include: An initial first transparent conductive layer is formed on the side of the first doped semiconductor layer away from the first region; The light-trapping particles are formed on the surface of the initial first transparent conductive layer away from the substrate; The light-trapping particles are located on the surface of the initial first transparent conductive layer away from the substrate, or a portion of the light-trapping particles are embedded in the initial first transparent conductive layer; the light-trapping particles and the initial first transparent conductive layer together constitute the first transparent conductive layer.

14. A stacked battery, characterized in that, include: The bottom battery is a back contact battery as described in any one of claims 1 to 8, or a back contact battery formed by the manufacturing method of a back contact battery as described in any one of claims 9 to 13; A top battery, located on one side of the bottom battery.

15. A photovoltaic module, characterized in that, include: The battery string is formed by connecting multiple back-contact batteries as described in any one of claims 1 to 8, or by connecting multiple back-contact batteries formed by the manufacturing method of the back-contact batteries as described in any one of claims 9 to 13, or by connecting multiple stacked batteries as described in claim 14. An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

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