Back contact battery and photovoltaic module

Abstract

The invention relates to the photovoltaic field, and provides a back contact cell and a photovoltaic module, the back contact cell comprises a substrate, a first passivation layer, a plurality of isolation parts, a first doped conductive layer, a second doped conductive layer, a first electrode and a second electrode, the first passivation layer is located on a first surface of the substrate; the plurality of isolation parts are arranged on the surface, deviating from the substrate, of the first passivation layer at intervals; doped elements in the first doped conductive layer and doped elements in the second doped conductive layer have different conductive types; the first electrode is in electrical contact with the first doped conductive layer; the second electrode is in electrical contact with the second doped conductive layer; the orthographic projection of the isolation part on the second surface is separated from the orthographic projection of the first electrode on the second surface, and the orthographic projection of the isolation part on the second surface is separated from the orthographic projection of the second electrode on the second surface. The performance of the back contact battery can be improved at least, and the structural stability of the stacked back contact battery is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of photovoltaics, and particularly to a back-contact battery and a photovoltaic module. Background Art

[0002] With the gradual depletion of fossil energy, solar energy, as a new energy alternative, is being used more and more widely. A solar cell is a device that converts the light energy of the sun into electrical energy. The solar cell utilizes the photovoltaic effect to generate carriers, and then uses electrodes to extract the carriers, thereby facilitating the effective utilization of electrical energy.

[0003] Current solar cells mainly include IBC (Interdigitated Back Contact) cells, TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (Passivated Emitter and Real Cell), and heterojunction cells, etc.

[0004] The front side of the back-contact battery has no metal grid lines, and the positive and negative metal electrodes are arranged in a finger-like pattern on the back side. Due to the absence of grid line obstruction on the front side, it has a relatively good photoelectric conversion efficiency. However, during the process of stacking multiple back-contact batteries after printing the metal electrodes on the batteries and then assembling them into a module at the module end, the stacked back-contact batteries are likely to cause damage to the front passivation layer, affecting the performance of the back-contact battery. Summary of the Invention

[0005] Embodiments of the present disclosure provide a back-contact battery and a photovoltaic module, which can at least improve the performance of the back-contact battery and enhance the structural stability of the stacked back-contact batteries.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a back-contact battery, which includes: a substrate, the substrate includes opposite first and second surfaces, the second surface includes alternately and spaced first and second regions, and a spacer region located between the first and second regions; a first passivation layer, the first passivation layer is located on the first surface; a plurality of isolation parts, the plurality of isolation parts are spaced on the surface of the first passivation layer facing away from the substrate; a first doped conductive layer and a second doped conductive layer, the first doped conductive layer is located on the first region, the second doped conductive layer is located on the second region, and the doping elements in the first doped conductive layer and the doping elements in the second doped conductive layer have different conduction types; a first electrode, the first electrode is located on the second surface and is in electrical contact with the first doped conductive layer; a second electrode, the second electrode is located on the second surface and is in electrical contact with the second doped conductive layer; wherein, the orthographic projection of the isolation part on the second surface is spaced from the orthographic projection of the first electrode on the second surface, and the orthographic projection of the isolation part on the second surface is spaced from the orthographic projection of the second electrode on the second surface.

[0007] In some embodiments, the back-contact battery further includes: a second passivation layer, the second passivation layer is located on the surfaces of the first doped conductive layer and the second doped conductive layer facing away from the substrate, and the second passivation layer is also located on the spacer region; the thickness of the isolation part is a first thickness T, based on the surface of the second passivation layer on the spacer region facing away from the substrate, the height of the surface of the first electrode facing away from the substrate is a first height H1, the height of the surface of the second electrode facing away from the substrate is a second height H2, and the back-contact battery satisfies: H1≥H2, 1.5H1≤T≤10H1.

[0008] In some embodiments, the first height H1 is 5 μm to 11 μm, the second height H2 is 3 μm to 9 μm, and the first thickness T is 7 μm to 50 μm.

[0009] In some embodiments, the distance between any two adjacent isolation parts in the first direction is the same, and the distance between any two adjacent isolation parts in the second direction is the same.

[0010] In some embodiments, the distance between any two adjacent isolation parts in the first direction is 3 mm to 10 mm, and the distance between any two adjacent isolation parts in the second direction is 3 mm to 10 mm.

[0011] In some embodiments, the back contact battery further includes: a first electrical contact point that is in electrical contact with the first electrode, and the positive projections of the plurality of isolation portions on the second surface are symmetrically distributed about the geometric center of the positive projection of the first electrical contact point on the second surface; a second electrical contact point that is in electrical contact with the second electrode, and the positive projections of the plurality of isolation portions on the second surface are symmetrically distributed about the geometric center of the positive projection of the second electrical contact point on the second surface.

[0012] In some embodiments, the distance between the geometric center of the positive projection of the first electrical contact point on the second surface and the geometric center of the positive projection of an adjacent isolation portion on the second surface is 2 mm to 8 mm; the distance between the geometric center of the positive projection of the second electrical contact point on the second surface and the geometric center of the positive projection of an adjacent isolation portion on the second surface is 2 mm to 8 mm.

[0013] In some embodiments, the ratio of the total area of the positive projections of the plurality of isolation portions on the second surface to the area of the second surface is 0.01 to 0.05.

[0014] In some embodiments, the isolation portion is made of a transparent material.

[0015] According to some embodiments of the present disclosure, on the other hand, the present disclosure also provides a photovoltaic module, which includes: a battery string formed by connecting a plurality of back contact batteries as described in any of the above embodiments; an encapsulation film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulation film facing away from the battery string.

[0016] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages: In the back contact battery provided by the embodiments of the present disclosure, a plurality of isolation portions are provided on the surface of the first passivation layer facing away from the substrate. When another back contact battery is stacked on the first surface of a back contact battery, the isolation portion can prevent the other back contact battery from directly contacting the first passivation layer on the back contact battery, avoiding the situation that the first passivation layer is scratched or even damaged by the other back contact battery, thereby ensuring the passivation effect of the first passivation layer and improving the performance of the back contact battery.

[0017] In addition, the orthographic projection of the isolation portion on the second surface is spaced apart from the orthographic projection of the first electrode on the second surface, and the orthographic projection of the isolation portion on the second surface is spaced apart from the orthographic projection of the second electrode on the second surface. When another back contact battery is stacked on the first surface of a back contact battery, the isolation portion can be spaced apart from the first electrode of the other back contact battery and the second electrode of the other back contact battery, which can prevent the isolation portion on one back contact battery from directly contacting the first electrode and the second electrode of the other back contact battery. On the one hand, it can prevent the isolation portion from lifting the first electrode and the second electrode of the other back contact battery, resulting in a relatively high overall height of the stacked back contact batteries and an unstable structure of the stacked back contact batteries. That is, it can improve the structural stability of the stacked back contact batteries. On the other hand, it can prevent the force between the stacked back contact batteries from concentrating on the first electrode and the second electrode, avoiding damage to the first electrode and the second electrode and thus reducing the performance of the back contact battery. That is, it can protect the first electrode and the second electrode and improve the performance of the back contact battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not limit the embodiments. Unless otherwise stated, the figures in the drawings do not constitute a proportional limitation. To more clearly illustrate the technical solutions in the embodiments of the present disclosure or the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 FIG. [X] is a schematic structural diagram of a back contact battery provided by an embodiment of the present disclosure; Figure 2 FIG. [X] is a schematic structural diagram of two stacked back contact batteries provided by an embodiment of the present disclosure; Figure 3 FIG. [X] is a schematic structural diagram of the orthographic projections of multiple isolation portions on the second surface in a back contact battery provided by an embodiment of the present disclosure; Figure 4 FIG. [X] is a partial structural schematic diagram of the orthographic projections of the first electrical contact point, the first electrode, and the isolation portion on the second surface in a back contact battery provided by an embodiment of the present disclosure; Figure 5 FIG. [X] is a partial structural schematic diagram of the orthographic projections of the second electrical contact point, the second electrode, and the isolation portion on the second surface in a back contact battery provided by an embodiment of the present disclosure; Figure 6 FIG. [X] is a partial three-dimensional structural schematic diagram of a battery string in a photovoltaic module provided by an embodiment of the present disclosure; Figure 7A schematic cross-sectional structure diagram of a photovoltaic module provided by an embodiment of the present disclosure.

[0020] Explanation of reference numerals: 10, back contact cell; 10a, first back contact cell; 10b, second back contact cell; 100, substrate; 110, first surface; 120, second surface; 130, first region; 140, second region; 150, spacer region; 101, first passivation layer; 102, isolation portion; 103, first doped conductive layer; 104, second doped conductive layer; 105, first electrode; 115, first main grid; 125, first fine grid; 106, second electrode; 116, second main grid; 126, second fine grid; 107, second passivation layer; 108, first electrical contact point; 109, second electrical contact point; 21, encapsulation film; 22, cover plate; 23, solder ribbon. Detailed implementation manners

[0021] As can be seen from the background art, during the process of sending the battery printed with metal electrodes to the module end for assembly to form a module, multiple back contact cells are usually stacked and arranged. Among them, the back surface of one back contact cell is in direct contact with the front surface of another back contact cell, and the metal electrode on the back surface of one back contact cell will damage the front passivation layer of another back contact cell, resulting in a reduced passivation effect of the front passivation layer and poor performance of the back contact cell.

[0022] An embodiment of the present disclosure provides a back contact cell and a photovoltaic module. When another back contact cell is stacked on the first surface of one back contact cell, the isolation portion can prevent the other back contact cell from directly contacting the first passivation layer on the one back contact cell, avoiding scratching the first passivation layer by the other back contact cell, thereby ensuring the passivation effect of the first passivation layer and improving the performance of the back contact cell.

[0023] In addition, the orthographic projection of the isolation portion on the second surface is spaced from the orthographic projection of the first electrode on the second surface, and the orthographic projection of the isolation portion on the second surface is spaced from the orthographic projection of the second electrode on the second surface. When another back contact cell is stacked on the first surface of one back contact cell, it can prevent the isolation portion on one back contact cell from directly contacting the first electrode and the second electrode of the other back contact cell, resulting in a relatively high overall height of the stacked back contact cells and an unstable structure of the stacked back contact cells. It can also prevent the acting force between the stacked back contact cells from concentrating on the first electrode and the second electrode, damaging the first electrode and the second electrode and thus reducing the performance of the back contact cell. That is, it can protect the first electrode and the second electrode and improve the performance of the back contact cell.

[0024] 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-secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is more than two, unless otherwise specifically and clearly defined.

[0025] Reference to "embodiments" in this document means 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, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0026] 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 three relationships can exist. For example, A and / or B can represent three situations: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " in this document generally represents an "or" relationship between the associated objects before and after.

[0027] In the description of the embodiments of the present disclosure, the term "a plurality of" refers to more than two (including two). Similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0028] In the description of the embodiments of the present disclosure, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "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 indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure.

[0029] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "attachment", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0030] 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) being 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. Conversely, when describing a component being on the surface of another component or when the surface of one component forms or is provided with another component, it means that there is no third component between the two components. In addition, when describing a component being "substantially" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a partial edge of the entire surface.

[0031] 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 being "on / at" another component, it can be "directly on" the other component (i.e., on the surface of the other component with 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 no other components are located between them.

[0032] 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 provided for readers to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can still be implemented.

[0033] Figure 1 It is a schematic structural diagram of a back-contact battery provided for the embodiments of the present disclosure.

[0034] Reference Figure 1, The back-contact battery includes: a substrate 100, a first passivation layer 101, a plurality of isolation portions 102, a first doped conductive layer 103, a second doped conductive layer 104, a first electrode 105, and a second electrode 106. The substrate 100 includes opposite first and second surfaces 110 and 120. The second surface 120 includes alternating and spaced-apart first and second regions 130 and 140, and a spacer region 150 located between the first region 130 and the second region 140; the first passivation layer 101 is located on the first surface 110; the plurality of isolation portions 102 are spaced apart on the surface of the first passivation layer 101 facing away from the substrate 100; the first doped conductive layer 103 is located on the first region 130, the second doped conductive layer 104 is located on the second region 140, and the doping elements in the first doped conductive layer 103 and the doping elements in the second doped conductive layer 104 have different conduction types; the first electrode 105 is located on the second surface 120 and is in electrical contact with the first doped conductive layer 103; the second electrode 106 is located on the second surface 120 and is in electrical contact with the second doped conductive layer 104. Among them, the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the first electrode 105 on the second surface 120, and the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the second electrode 106 on the second surface 120.

[0035] Figure 2 FIG. 4 is a schematic structural diagram of a stacked structure of two back-contact batteries provided by an embodiment of the present disclosure.

[0036] It should be noted that Figure 2 In FIG. 4, in order to better distinguish and clearly illustrate the two stacked back-contact batteries 10, one back-contact battery is defined as the first back-contact battery 10a, and the other back-contact battery is defined as the second back-contact battery 10b. Among them, the other back-contact battery stacked directly above one back-contact battery means that the second back-contact battery 10b is stacked directly above the first back-contact battery 10a.

[0037] With reference to Figure 1 and Figure 2 , a plurality of isolation portions 102 are provided on the surface of the first passivation layer 101 facing away from the substrate 100. When the second back-contact battery 10b is stacked on the first surface 110 of the first back-contact battery 10a, the isolation portion 102 can prevent the second back-contact battery 10b from directly contacting the first passivation layer 101 on the first back-contact battery 10a, avoiding the first passivation layer 101 from being scratched by the second back-contact battery 10b, thereby ensuring the passivation effect of the first passivation layer 101 and improving the performance of the back-contact battery 10.

[0038] In addition, the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the first electrode 105 on the second surface 120, and the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the second electrode 106 on the second surface 120. When the second back-contact battery 10b is stacked on the first surface 110 of the first back-contact battery 10a, the isolation portion 102 can be spaced apart from the first electrode 105 of the second back-contact battery 10b and spaced apart from the second electrode 106 of the second back-contact battery 10b, which can prevent the isolation portion 102 on the first back-contact battery 10a from directly contacting the first electrode 105 and the second electrode 106 of the second back-contact battery 10b. On the one hand, it can prevent the isolation portion 102 from lifting the first electrode 105 and the second electrode 106 of the second back-contact battery 10b, resulting in a relatively high overall height of the stacked back-contact batteries 10 and an unstable structure of the stacked back-contact batteries 10. That is, the structural stability of the stacked back-contact batteries 10 can be improved. On the other hand, it can prevent the force between the stacked back-contact batteries 10 from concentrating on the first electrode 105 and the second electrode 106, avoiding damage to the first electrode 105 and the second electrode 106 and thus reducing the performance of the back-contact battery 10. That is, the first electrode 105 and the second electrode 106 can be protected, thereby improving the performance of the back-contact battery 10.

[0039] It should be noted that when the first back-contact battery 10a and the second back-contact battery 10b are stacked, in order to stack the back-contact batteries 10 neatly, usually the first surface 110 of the first back-contact battery 10a is placed facing the second surface 120 of the second back-contact battery 10b. That is, the orthographic projection of the first surface 110 of the first back-contact battery 10a on the ground coincides with the orthographic projection of the second surface 120 of the second back-contact battery 10b on the ground. Also, the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the first electrode 105 on the second surface 120, and the orthographic projection of the isolation portion 102 on the second surface 120 is spaced apart from the orthographic projection of the second electrode 106 on the second surface 120. Therefore, the isolation portion 102 on the first back-contact battery 10a can be spaced apart from the first electrode 105 of the second back-contact battery 10b and spaced apart from the second electrode 106 of the second back-contact battery 10b.

[0040] In some embodiments, the back-contact battery 10 can be an IBC battery, an HPBC (Hybrid Passivated Back Contact) battery, a TBC battery that combines TOPCON technology and IBC technology, or an HBC battery that combines HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back-contact batteries.

[0041] The substrate 100 is configured to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate 100.

[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, for example, it may be silicon or germanium. Among them, the elemental semiconductor material may be in single crystal state, polycrystalline state, amorphous state or microcrystalline state (a state with both single crystal state and amorphous state is called microcrystalline state). For example, silicon may be at least one of single crystal silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon.

[0043] In some embodiments, the material of the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include but are not limited to silicon germanide, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide and other materials.

[0044] The substrate 100 may also be a sapphire substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate.

[0045] 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 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, and the P-type doping element may be at least one of Group III elements such as boron (B), aluminum (Al), gallium (Ga) or indium (In).

[0046] The substrate 100 has opposite first surface 110 and second surface 120. In some embodiments, if the back-contact battery 10 is a single-sided battery, the first surface 110 of the substrate 100 may be used as the light-receiving surface for receiving incident light, and the second surface 120 is used as the backlight surface. In some embodiments, if the back-contact battery is a double-sided battery, both the first surface and the second surface of the substrate can be used as the light-receiving surface and can be used to receive incident light. It can be understood that the backlight surface referred to in the embodiments of the present application can also receive incident light, but the degree of receiving incident light is weaker than that of the light-receiving surface, so it is defined as the backlight surface.

[0047] In some embodiments, the texturing process can be performed on at least one of the first surface 110 or the second surface 120 of the substrate 100 to form a textured surface on at least one of the first surface 110 or the second surface 120 of the substrate 100. In this way, the absorption and utilization rate of the incident light by the first surface 110 and the second surface 120 of the substrate 100 can be enhanced. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, the pyramid textured surface not only reduces the reflectivity of the surface of the substrate 100, but also forms an optical trap, enhancing the absorption effect of the substrate 100 on the incident light and improving the photoelectric conversion efficiency of the back-contact battery 10.

[0048] Specifically, if the back-contact battery 10 is a single-sided battery, a textured surface can be formed on the light-receiving surface of the substrate 100, for example, it can be a pyramid textured surface, and the backlight surface of the substrate 100 can be a polished surface, that is, the backlight surface of the substrate 100 is flatter than the light-receiving surface. It should be noted that for a single-sided battery, a textured surface can also be formed on both the light-receiving surface and the backlight surface of the substrate 100.

[0049] If the back-contact battery is a double-sided battery, textured surfaces can be formed on both the light-receiving surface and the backlight surface of the substrate.

[0050] The first passivation layer 101 is located on the first surface 110 and is used to passivate the substrate 100, reduce the interface state density, and improve the performance of the back-contact battery 10.

[0051] The first passivation layer 101 can include a single-layer film structure or a stacked film structure, and the material of the first passivation layer 101 can include any one or more of materials such as silicon oxide, silicon nitride, silicon oxynitride, carbon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0052] The first region 130 is the region where the positive projection of the first doped conductive layer 103 on the second surface 120 is located, the second region 140 is the region where the positive projection of the second doped conductive layer 104 on the second surface 120 is located, and the spacer region 150 is located between the first region 130 and the second region 140.

[0053] The doping element in the first doped conductive layer 103 is one of a P-type doping element and an N-type doping element, and the doping element in the second doped conductive layer 104 is the other of a P-type doping element and an N-type doping element.

[0054] The material of the first doped conductive layer 103 can be at least one of amorphous silicon, silicon carbide, microcrystalline silicon, or polycrystalline silicon.

[0055] The material of the second doped conductive layer 104 can be at least one of amorphous silicon, silicon carbide, microcrystalline silicon, or polycrystalline silicon.

[0056] The first electrode 105 is in electrical contact with the first doped conductive layer 103 and is used to transmit the current collected by the first doped conductive layer 103.

[0057] The second electrode 106 is in electrical contact with the second doped conductive layer 104 and is used to transmit the current collected by the second doped conductive layer 104.

[0058] In some embodiments, the back-contact battery 10 may further include a second passivation layer 107. The second passivation layer 107 is located on the surfaces of the first doped conductive layer 103 and the second doped conductive layer 104 facing away from the substrate 100, and the second passivation layer 107 is also located on the spacer 150. The thickness of the isolation portion 102 is the first thickness T. Based on the surface of the second passivation layer 107 on the spacer 150 facing away from the substrate 100, the height of the surface of the first electrode 105 facing away from the substrate 100 is the first height H1, and the height of the surface of the second electrode 106 facing away from the substrate 100 is the second height H2. The back-contact battery 10 satisfies: H1≥H2, 1.5H1≤T≤10H1. When the first thickness T is within the above range, it can be ensured that the first electrode 105 and the second electrode 106 do not contact the first passivation layer 101 of the second back-contact battery 10b, so as not to damage the first passivation layer 101 of the second back-contact battery 10b, and it can also avoid affecting the absorption of sunlight by the back-contact battery 10 due to the too thick thickness of the isolation portion 102.

[0059] The second passivation layer 107 can passivate the surface of the substrate 100, reduce the interface state density, and improve the performance of the back-contact battery 10.

[0060] The second passivation layer 107 may include a single-layer film structure or a stacked film structure, and the material of the second passivation layer 107 may include any one or more of materials such as silicon oxide, silicon nitride, silicon oxynitride, carbon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0061] In some embodiments, the first height H1 is 5μm to 11μm, such as 5μm to 7μm, 7μm to 9μm, or 9μm to 11μm. Exemplarily, the first height H1 may be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or 11μm.

[0062] In some embodiments, the second height H2 is 3μm to 9μm, such as 3μm to 5μm, 5μm to 7μm, or 7μm to 9μm. Exemplarily, the second height H2 may be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, or 9μm.

[0063] In some embodiments, the first thickness T is 7 μm to 50 μm, such as 7 μm to 15 μm, 15 μm to 25 μm, 25 μm to 35 μm, or 35 μm to 50 μm. Exemplarily, the first thickness T may be 7 μm, 11 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. When the first thickness T is within the above range, it can ensure that the first electrode 105 and the second electrode 106 do not contact each other, thus not damaging the first passivation layer 101 of the second back contact cell 10b. It can also avoid the excessive thickness of the isolation part 102 from affecting the absorption of sunlight by the back contact cell 10.

[0064] Figure 3 FIG. is a schematic structural diagram of the orthographic projection of multiple isolation parts on the second surface in the back contact cell provided by the embodiment of the present disclosure.

[0065] It should be noted that Figure 3 FIG. shows the case where the orthographic projection of the isolation part on the second surface is circular. In fact, the shape of the orthographic projection of the isolation part on the second surface can also be any shape such as a rectangle, a triangle, a polygon, etc.

[0066] Referring to Figure 2 and Figure 3 , in some embodiments, the distance between any two adjacent isolation parts 102 along the first direction X is the same, and the distance between any two adjacent isolation parts 102 along the second direction Y is the same. With such a setting, the isolation parts 102 are evenly distributed on the first surface 110, and the isolation parts 102 can provide a uniform supporting force for other back contact cells 10 (such as the second back contact cell 10b) stacked above the isolation parts 102, which is beneficial to improving the stability of the stacked back contact cells 10.

[0067] Wherein, the distance between two adjacent isolation parts 102 along the first direction X is the straight-line distance between the geometric centers of two adjacent isolation parts 102 along the first direction X, and the distance between two adjacent isolation parts 102 along the second direction Y is the straight-line distance between the geometric centers of two adjacent isolation parts 102 along the second direction Y.

[0068] The first direction X and the second direction Y may intersect perpendicularly.

[0069] In some embodiments, the distance between any two adjacent isolation portions 102 in the first direction X is 3 mm to 10 mm, such as 3 mm to 5 mm, 5 mm to 8 mm, or 8 mm to 10 mm. Exemplarily, the distance between any two adjacent isolation portions 102 in the first direction X may be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. When the distance between any two adjacent isolation portions 102 in the first direction X is within the above range, the isolation portion 102 can provide sufficient support force for other back-contact batteries 10 stacked above the isolation portion 102, and can also avoid the situation that the number of isolation portions 102 is too large due to the too-close distance between adjacent isolation portions 102 in the first direction X, which affects the sunlight absorption of the back-contact battery 10.

[0070] The distance between any two adjacent isolation portions 102 in the second direction Y is 3 mm to 10 mm, such as 3 mm to 5 mm, 5 mm to 8 mm, or 8 mm to 10 mm. Exemplarily, the distance between any two adjacent isolation portions 102 in the second direction Y may be 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm. When the distance between any two adjacent isolation portions 102 in the second direction Y is within the above range, the isolation portion 102 can provide sufficient support force for other back-contact batteries 10 stacked above the isolation portion 102, and can also avoid the situation that the number of isolation portions 102 is too large due to the too-close distance between adjacent isolation portions 102 in the second direction Y, which affects the sunlight absorption of the back-contact battery 10.

[0071] In some embodiments, the ratio of the total area of the orthographic projections of multiple isolation portions 102 on the second surface 120 to the area of the second surface 120 is 0.01 to 0.05, such as 0.01, 0.02, 0.03, 0.04, or 0.05. When the ratio of the total area of the orthographic projections of multiple isolation portions 102 on the second surface 120 to the area of the second surface 120 is within the above range, it can be avoided that because the total area of the orthographic projections of the isolation portion 102 on the second surface 120 is too small, the isolation portion 102 is difficult to provide sufficient support force for other back-contact batteries 10 stacked above the isolation portion 102 (for example, the isolation portion 102 on the first back-contact battery 10a provides sufficient support force for the second back-contact battery 10b), and it can also be avoided that because the orthographic projection area of the isolation portion 102 on the second surface 120 is too large, the situation that the back-contact battery 10 absorbs sunlight is affected.

[0072] In some embodiments, the area of the orthographic projection of a single isolation portion 102 on the second surface 120 is 0.01 mm 2 ~80 mm 2 . For example, 0.01 mm 2 ~1 mm 2 、1 mm 2 ~20 mm 2, 20 mm 2 ~40 mm 2 , 40 mm 2 ~60 mm 2 or 60 mm 2 ~80 mm 2 。Exemplarily, the orthographic projection area of a single isolation part 102 on the second surface 120 may be 0.01 mm 2 , 0.05 mm 2 , 0.1 mm 2 , 0.5 mm 2 , 1 mm 2 , 5 mm 2 , 10 mm 2 , 15 mm 2 , 20 mm 2 , 30 mm 2 , 40 mm 2 , 50 mm 2 , 60 mm 2 , 70 mm 2 or 80 mm 2 。When the orthographic projection area of a single isolation part 102 on the second surface 120 is within the above range, it can avoid the situation that due to the too small orthographic projection area of a single isolation part 102, it is difficult for a single isolation part 102 to provide sufficient supporting force for other back-contact batteries 10 stacked above the isolation part 102, and it can also avoid the situation that due to the too large orthographic projection area of a single isolation part 102, the light-shielding area of the back-contact battery 10 is too large, resulting in more optical losses in the battery.

[0073] In some embodiments, the total orthographic projection area of multiple isolation parts 102 on the second surface 120 is 300 mm 2 ~1700 mm 2 , for example, 300 mm 2 ~700 mm 2 , 700 mm 2 ~1100 mm 2 , 1100 mm 2 ~1400 mm 2 or 1400 mm 2 ~1700 mm 2 。Exemplarily, the total orthographic projection area of multiple isolation parts 102 on the second surface 120 may be 300 mm 2 , 500 mm 2 , 700 mm 2 , 900 mm 2 , 1000 mm 2 , 1100 mm 2 , 1250 mm 2 , 1400 mm 2, 1550 mm 2 or 1700 mm 2 . The total area of the orthographic projections of multiple isolation parts 102 on the second surface 120 is within the above range, which can avoid the situation that because the total area of the orthographic projections of multiple isolation parts 102 on the second surface 120 is too small, it is difficult for a single isolation part 102 to provide sufficient supporting force for other back-contact batteries 10 stacked above the isolation part 102, and can also avoid the situation that because the area of the orthographic projections of multiple isolation parts 102 on the second surface 120 is too large, the light-shielding area of the back-contact battery 10 is too large, resulting in more optical losses in the battery.

[0074] In some embodiments, the isolation part 102 is made of a transparent material. In this way, the first surface 110 can absorb more sunlight, which is beneficial to improving the performance of the back-contact battery 10.

[0075] In some embodiments, the material of the isolation part 102 can be one or a combination of acrylic resin, epoxy resin, polyurethane, and silicone. Materials such as acrylic resin, epoxy resin, polyurethane, and silicone in the glue system have high transparency, good light and color retention, and water and chemical resistance, low cost, and are not easy to damage the first passivation layer 101 on the first surface 110 and other back-contact batteries 10 in contact with the isolation part 102, further reducing optical losses and saving costs.

[0076] In some embodiments, the orthographic projection of the isolation part 102 on the second surface 120 is located within the spacer area 150. In this way, when the first back-contact battery 10a and the second back-contact battery 10b are stacked, and the first surface 110 of the first back-contact battery 10a is placed facing the second surface 120 of the second back-contact battery 10b, the isolation parts 102 of the first back-contact battery 10a are all in contact with the second passivation layer 107 on the spacer area 150 of the second back-contact battery 10b, which can avoid the situation that because some of the top of the isolation parts 102 contact the second passivation layer 107 of the second back-contact battery 10b, and some of the isolation parts 102 contact the first doped conductive layer 103 or the second doped conductive layer 104 of the second back-contact battery 10b, resulting in uneven heights of the film layers contacted by the top of the isolation parts 102 relative to the first surface 110, causing the stacked back-contact batteries 10 to tilt. That is, the isolation parts 102 of the first back-contact battery 10a are all in contact with the second passivation layer 107 on the spacer area 150 of the second back-contact battery 10b, which can ensure that the heights of the tops of multiple isolation parts 102 relative to the film layers contacted on the second back-contact battery 10b are as the same as possible relative to the first surface 110, which is beneficial to improving the structural stability of the stacked back-contact batteries 10.

[0077] Figure 4A partial structural schematic diagram of the positive projection of the first electrical contact point, the first electrode, and the isolation part on the second surface in the back contact battery provided by the embodiments of the present disclosure; Figure 5 A partial structural schematic diagram of the positive projection of the second electrical contact point, the second electrode, and the isolation part on the second surface in the back contact battery provided by the embodiments of the present disclosure.

[0078] Reference Figure 2 、 Figure 4 and Figure 5 In some embodiments, the back contact battery 10 further includes: a first electrical contact point 108 and a second electrical contact point 109. The first electrical contact point 108 is in electrical contact with the first electrode 105, and the positive projections of the plurality of isolation parts 102 on the second surface 120 are symmetrically distributed about the geometric center of the positive projection of the first electrical contact point 108 on the second surface 120; the second electrical contact point 109 is in electrical contact with the second electrode 106, and the positive projections of the plurality of isolation parts 102 on the second surface 120 are symmetrically distributed about the geometric center of the positive projection of the second electrical contact point 109 on the second surface 120.

[0079] The first electrical contact point 108 is in electrical contact with the first electrode 105 and is used to provide a welding position for connecting the solder strip to the back contact battery 10 when the solder strip connects a plurality of back contact batteries 10 to form a battery string.

[0080] The second electrical contact point 109 is in electrical contact with the second electrode 106 and is used to provide a welding position for connecting the solder strip to the back contact battery 10 when the solder strip connects a plurality of back contact batteries 10 to form a battery string.

[0081] In some embodiments, the first electrode 105 includes a first main grid 115 and a first fine grid 125. The first fine grid 125 is in electrical contact with the first doped conductive layer 103, and the first main grid 115 is in electrical contact with the first fine grid 125. Among them, the first main grid 115 extends along the first direction X, and the first fine grid 125 extends along the second direction Y.

[0082] The second electrode 106 includes a second main grid 116 and a second fine grid 126. The second fine grid 126 is in electrical contact with the second doped conductive layer 104, and the second main grid 116 is in electrical contact with the second fine grid 126. Among them, the second main grid 116 extends along the first direction X, and the second fine grid 126 extends along the second direction Y.

[0083] The first electrical contact point 108 is located at the junction of the first main grid 115 and the first fine grid 125 of the first electrode 105, and the geometric center of the first electrical contact point 108 may coincide with the cross-connection point of the first main grid 115 and the first fine grid 125.

[0084] The second electrical contact point 109 is located at the junction of the second main grid 116 and the second fine grid 126 of the second electrode 106, and the geometric center of the second electrical contact point 109 may coincide with the cross-connection point of the second main grid 116 and the second fine grid 126.

[0085] It should be noted that Figure 2 the first electrode shown in Figure 2 is the first fine grid, the second electrode is the second fine grid, and Figure 2 the first main grid and the second main grid are not shown in

[0086] In addition, the performance of the back-contact battery 10 can be tested by bringing the probes of the testing device into contact with the first electrical contact point 108 and the second electrical contact point 109. When testing with the testing device, the testing device provides a pressing plate above the first surface 110 of the back-contact battery 10. The pressing plate will directly contact the isolation part 102 and apply a downward force to the isolation part 102, so that the probes of the testing device are in close contact with the first electrical contact point 108 and the second electrical contact point 109 respectively, so that the testing device can test the back-contact battery 10. Among them, the orthographic projections of the plurality of isolation parts 102 on the second surface 120 are symmetrically distributed about the geometric center of the orthographic projection of the first electrical contact point 108 on the second surface 120. When the back-contact battery 10 is being tested, the first surface 110 of the back-contact battery 10 is subjected to the acting force of the pressing plate on the isolation part 102, which can be balanced with the acting force of the probe on the first electrical contact point 108 on the second surface 120 of the back-contact battery 10. The first surface 110 of the back-contact battery 10 can be uniformly stressed, avoiding the occurrence of battery rupture or latent crack due to stress concentration. Similarly, the orthographic projections of the plurality of isolation parts 102 on the second surface 120 are symmetrically distributed about the geometric center of the orthographic projection of the second electrical contact point 109 on the second surface 120. When the back-contact battery 10 is being tested, the first surface 110 of the back-contact battery 10 is subjected to the acting force of the pressing plate on the isolation part 102, which can be balanced with the acting force of the probe on the second electrical contact point 109 on the second surface 120 of the back-contact battery 10. The first surface 110 of the back-contact battery 10 can be uniformly stressed, and the occurrence of battery rupture or latent crack due to stress concentration can also be avoided.

[0087] In some embodiments, referring to Figure 2 and Figure 4 , the distance D1 between the geometric center of the orthographic projection of the first electrical contact point 108 on the second surface 120 and the geometric center of the orthographic projection of the adjacent isolation part 102 on the second surface 120 is 2 mm to 8 mm; for example, 2 mm to 4 mm, 4 mm to 6 mm, or 6 mm to 8 mm. Exemplarily, the distance D1 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm. When the pressing plate of the testing device presses the isolation part 102 to make the probe of the testing device contact the first electrical contact point 108 on the second surface 120, if the distance D1 is too large, it is difficult for the isolation part 102 to provide an effective supporting force, resulting in rupture or latent crack of the back-contact battery 10 under the acting force of the pressing plate; if the distance D1 is too small, there is a risk that the orthographic projection of the isolation part 102 on the second surface 120 coincides with a part of the orthographic projection of the first electrode 105 on the second surface 120. In other words, within the above range of the distance D1, the isolation part 102 can provide sufficient supporting force to balance the acting force of the pressing plate on the first surface 110 of the back-contact battery 10, and can also avoid the orthographic projection of the isolation part 102 on the second surface 120 coinciding with a part of the orthographic projection of the first electrode 105 on the second surface 120.

[0088] Reference Figure 2 and Figure 5 The distance D2 between the geometric center of the positive projection of the second electrical contact point 109 on the second surface 120 and the geometric center of the positive projection of the adjacent isolation part 102 on the second surface 120 is 2 mm to 8 mm, such as 2 mm to 4 mm, 4 mm to 6 mm, or 6 mm to 8 mm. Exemplarily, the distance D2 can be 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, or 8 mm.

[0089] When the pressing plate of the test device presses the isolation part 102 to make the probe of the test device contact the second electrical contact point 109 on the second surface 120, if the distance D2 is too large, it is difficult for the isolation part 102 to provide an effective supporting force, resulting in the back-contact battery 10 being cracked or invisibly cracked under the action of the pressing plate; if the distance D2 is too small, there is a risk that the positive projection of the isolation part 102 on the second surface 120 partially overlaps with the positive projection of the second electrode 106 on the second surface 120. In other words, when the distance D2 is within the above range, the isolation part 102 can provide sufficient supporting force to balance the acting force of the pressing plate on the first surface 110 of the back-contact battery 10, and can also avoid the positive projection of the isolation part 102 on the second surface 120 partially overlapping with the positive projection of the second electrode 106 on the second surface 120.

[0090] Some embodiments of the present disclosure further provide a photovoltaic module, and the photovoltaic module may include the back-contact battery in any of the above embodiments. It should be noted that the same or corresponding parts as those in the above embodiments may be referred to the above embodiments, and will not be repeated hereinafter.

[0091] Figure 6 It is a partial three-dimensional structural schematic diagram of a battery string in a photovoltaic module provided by an embodiment of the present disclosure, Figure 7 It is a cross-sectional structural schematic diagram of a photovoltaic module provided by an embodiment of the present disclosure.

[0092] Reference Figure 6 and Figure 7 The photovoltaic module includes: a battery string, and the battery string is formed by connecting a plurality of back-contact batteries 10 as in any of the above embodiments. The photovoltaic module further includes an encapsulation adhesive film 21 and a cover plate 22. The encapsulation adhesive film 21 is used to cover the surface of the battery string, and the cover plate 22 is used to cover the surface of the encapsulation adhesive film 21 away from the battery string.

[0093] In some embodiments, every two adjacent back-contact batteries 10 among the plurality of back-contact batteries can be electrically connected through a solder strip 23.

[0094] In some embodiments, the encapsulation film 21 includes a first encapsulation layer and a second encapsulation layer. The first encapsulation layer covers one of the first and second surfaces of the back-contact battery 10, and the second encapsulation layer covers the other of the first and second surfaces of the back-contact battery 10. Specifically, at least one of the first encapsulation layer and the second encapsulation layer may be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate copolymer (EVA) film, a polyethylene octene elastomer (POE) film, or a polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulation layer and the second encapsulation layer may also be an EP film, an EPE film, or a PVP film. Among them, the EP film refers to a co-extruded film composed of an EVA film and a POE film stacked, the EPE film refers to a co-extruded film formed by sequentially stacking an EVA film + a POE film + an EVA film, and the PVP film refers to a co-extruded film formed by stacking a POE film + an EVA film + a POE film. The co-extruded film can be prepared by extruding one or more raw materials onto another film that has been made in sequence during the film processing, or by bonding different types of films that have been made together.

[0095] In some cases, there is a demarcation line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, there will no longer be the concept of the first encapsulation layer and the second encapsulation layer in the formed photovoltaic module, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 21.

[0096] In some embodiments, the cover plate 22 may be a cover plate with a light-transmitting function such as a glass cover plate or a plastic cover plate. Specifically, the surface of the cover plate 22 facing the encapsulation film 21 may be a concave-convex surface or a suede surface including a plurality of convex structures, so as to increase the utilization rate of incident light. The cover plate 22 includes a first cover plate and a second cover plate. The first cover plate faces the first encapsulation layer, and the second cover plate faces the second encapsulation layer.

[0097] Those of ordinary skill in the art can understand that the above embodiments are specific examples for implementing the present disclosure. In actual applications, various changes can be made to it in form and details without departing from the spirit and scope 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 present disclosure. Therefore, the protection scope of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A back-contact battery, characterized in that, Comprising: A substrate, the substrate including opposite first and second surfaces, the second surface including alternating and spaced-apart first and second regions, and a spaced region located between the first and second regions; A first passivation layer, the first passivation layer being located on the first surface; A plurality of isolation parts, the plurality of isolation parts being spaced and arranged on the surface of the first passivation layer facing away from the substrate; A first doped conductive layer and a second doped conductive layer, the first doped conductive layer being located on the first region, the second doped conductive layer being located on the second region, and the doping elements in the first doped conductive layer having a different conduction type from the doping elements in the second doped conductive layer; A first electrode, the first electrode being located on the second surface and being in electrical contact with the first doped conductive layer; A second electrode, the second electrode being located on the second surface and being in electrical contact with the second doped conductive layer; Wherein, the orthographic projection of the isolation part on the second surface is spaced from the orthographic projection of the first electrode on the second surface, and the orthographic projection of the isolation part on the second surface is spaced from the orthographic projection of the second electrode on the second surface.

2. The back contact battery according to claim 1, wherein, The back-contact battery further includes: A second passivation layer, the second passivation layer being located on the surfaces of the first doped conductive layer and the second doped conductive layer facing away from the substrate, and the second passivation layer is also located on the spaced region; The thickness of the isolation part is a first thickness T. Taking the surface of the second passivation layer on the spaced region facing away from the substrate as a reference, the height of the surface of the first electrode facing away from the substrate is a first height H1, and the height of the surface of the second electrode facing away from the substrate is a second height H2. The back-contact battery satisfies: H1≥H2, 1.5H1≤T≤10H1.

3. The back-contact battery according to claim 2, characterized in that, The first height H1 is 5μm to 11μm; the second height H2 is 3μm to 9μm; the first thickness T is 7μm to 50μm.

4. The back-contact battery according to claim 1, characterized in that, The distances between any two adjacent isolation parts along a first direction are the same, and the distances between any two adjacent isolation parts along a second direction are the same.

5. The back-contact battery according to claim 4, characterized in that, The distance between any two adjacent isolation parts along the first direction is 3mm to 10mm, and the distance between any two adjacent isolation parts along the second direction is 3mm to 10mm.

6. The back-contact battery according to claim 1, wherein, The back-contact battery further includes: A first electrical contact point, the first electrical contact point being in electrical contact with the first electrode, and the orthographic projections of the plurality of isolation parts on the second surface are symmetrically distributed about the geometric center of the orthographic projection of the first electrical contact point on the second surface; A second electrical contact point, the second electrical contact point being in electrical contact with the second electrode, and the orthographic projections of the plurality of isolation parts on the second surface are symmetrically distributed about the geometric center of the orthographic projection of the second electrical contact point on the second surface.

7. The back contact battery according to claim 6, wherein The distance between the geometric center of the orthographic projection of the first electrical contact point on the second surface and the geometric center of the orthographic projection of the adjacent isolation part on the second surface is 2mm to 8mm; the distance between the geometric center of the orthographic projection of the second electrical contact point on the second surface and the geometric center of the orthographic projection of the adjacent isolation part on the second surface is 2mm to 8mm.

8. The back contact battery according to claim 1, characterized in that, The ratio of the total area of the orthographic projections of the plurality of the isolation parts on the second surface to the area of the second surface is 0.01 to 0.

05.

9. The back contact battery according to claim 1, characterized in that, The isolation part is made of a transparent material.

10. A photovoltaic module, characterized in that, Comprising: a battery string formed by connecting a plurality of back contact batteries according to any one of claims 1 to 9; an encapsulation film for covering the surface of the battery string; a cover plate for covering the surface of the encapsulation film facing away from the battery string.

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