Back contact cells and photovoltaic modules

Abstract

The present disclosure relates to the field of photovoltaics, 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 portions, a first doped conductive layer, a second doped conductive layer, a first electrode, and a second electrode. The first passivation layer is on a first surface of the substrate. The plurality of isolation portions are spaced apart on a surface of the first passivation layer facing away from the substrate. The doped elements in the first doped conductive layer and the 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 projection of the isolation portions on a second surface is spaced apart from the projection of the first electrode on the second surface, and the projection of the isolation portions on the second surface is spaced apart from the projection of the second electrode on the second surface. The present disclosure can at least improve the performance of the back contact cell and improve the structural stability of the stacked back contact cells.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of photovoltaics, and in particular to a back contact cell and a photovoltaic module. BACKGROUND

[0002] With the gradual depletion of fossil energy, solar energy is used more and more widely as a new energy alternative. Solar cells are devices that convert the light energy of the sun into electrical energy. Solar cells use the photovoltaic principle to generate carriers, and then use electrodes to lead out the carriers, thereby facilitating the effective use 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 back contact cell has no metal grid lines on the front surface, and the positive and negative metal electrodes are arranged in an interdigital manner on the back surface. Because there is no grid line on the front surface, the back contact cell has good photoelectric conversion efficiency. However, in the process of printing metal electrodes on the cell and then assembling the cell to form a module, multiple back contact cells are stacked, and the stacked back contact cells are prone to damage the front passivation layer, affecting the performance of the back contact cell. SUMMARY

[0005] The embodiments of the present disclosure provide a back contact cell and a photovoltaic module, which can at least improve the performance of the back contact cell and improve the structural stability of the stacked back contact cells.

[0006] According to some embodiments of the present disclosure, the present disclosure provides a back contact cell, comprising: a substrate, the substrate comprising a first face and a second face opposite to each other, the second face comprising first regions and second regions arranged alternately and spaced apart, and a spacing region between the first regions and the second regions; a first passivation layer on the first face; a plurality of isolation portions spaced apart on a surface of the first passivation layer away from the substrate; a first doped conductive layer on the first regions and a second doped conductive layer on the second regions, the doped elements in the first doped conductive layer and the doped elements in the second doped conductive layer having different conductive types; a first electrode on the second face and in electrical contact with the first doped conductive layer; and a second electrode on the second face and in electrical contact with the second doped conductive layer; wherein a projection of the isolation portions on the second face is spaced apart from a projection of the first electrode on the second face, and a projection of the isolation portions on the second face is spaced apart from a projection of the second electrode on the second face.

[0007] In some embodiments, the back contact cell further comprises: a second passivation layer on a surface of the first doped conductive layer and the second doped conductive layer away from the substrate, the second passivation layer also being on the spacing region; a thickness of the isolation portions is a first thickness T, a height of a surface of the first electrode away from the substrate is a first height H1, a height of a surface of the second electrode away from the substrate is a second height H2, and the back contact cell satisfies H1≥H2 and 1.5H1≤T≤10H1.

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

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

[0010] In some embodiments, the distance between any two adjacent isolation portions along the first direction is 3mm~10mm, and the distance between any two adjacent isolation portions along the second direction is 3mm~10mm.

[0011] In some embodiments, the back contact cell further comprises: a first electrical contact point in electrical contact with the first electrode, a plurality of the isolation portions in the second face projection are symmetrically distributed about a geometric center of the first electrical contact point in the second face projection; a second electrical contact point in electrical contact with the second electrode, a plurality of the isolation portions in the second face projection are symmetrically distributed about a geometric center of the second electrical contact point in the second face projection.

[0012] In some embodiments, a distance between the geometric center of the first electrical contact point in the second face projection and the geometric center of the adjacent isolation portion in the second face projection is 2mm-8mm; a distance between the geometric center of the second electrical contact point in the second face projection and the geometric center of the adjacent isolation portion in the second face projection is 2mm-8mm.

[0013] In some embodiments, a ratio of a total area of the plurality of the isolation portions in the second face projection to an area of the second face is 0.01-0.05.

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

[0015] According to some embodiments of the present disclosure, another aspect of the present disclosure further provides a photovoltaic module, comprising: a cell string connected by a plurality of back contact cells according to any one of the above embodiments; an encapsulation adhesive film used to cover a surface of the cell string; and a cover plate used to cover a surface of the encapsulation adhesive film away from the cell string.

[0016] The technical solutions provided by the embodiments of the present disclosure have at least the following advantages:

[0017] In the back contact cell provided by the embodiments of the present disclosure, a plurality of isolation portions are arranged on the surface of the first passivation layer away from the substrate. When another back contact cell is stacked on the first surface of a back contact cell, the isolation portions can avoid the direct contact of another back contact cell with the first passivation layer on a back contact cell, avoid the scratch and even the damage of the first passivation layer by another back contact cell, so as to ensure the passivation effect of the first passivation layer and improve the performance of the back contact cell.

[0018] In addition, the projection of the isolation portion on the second surface is spaced apart from the projection of the first electrode on the second surface, and the projection of the isolation portion on the second surface is spaced apart from the projection of the second electrode on the second surface. When another back contact battery is stacked on the first surface of the back contact battery, the isolation portion can be spaced apart from the first electrode of another back contact battery and spaced apart from the second electrode of another back contact battery, and direct contact between the isolation portion on the back contact battery and the first electrode and the second electrode of another back contact battery can be avoided. On the one hand, the isolation portion can avoid lifting the first electrode and the second electrode of another back contact battery, resulting in a higher overall height of the stacked back contact battery and an unstable structure of the stacked back contact battery, that is, the structural stability of the stacked back contact battery can be improved. On the other hand, the force between the stacked back contact batteries can be concentrated 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, the first electrode and the second electrode can be protected, and the performance of the back contact battery can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0019] One or more embodiments are illustrated by way of example in the drawings that are not intended to be limiting of the application, unless otherwise specifically indicated, the drawings showing an exemplary embodiment of the application, and wherein:

[0020] Figure 1 A structural schematic diagram of a back contact battery provided by an embodiment of the present disclosure;

[0021] Figure 2 A structural schematic diagram of two stacked back contact batteries provided by an embodiment of the present disclosure;

[0022] Figure 3 A structural schematic diagram of the projection of a plurality of isolation portions on the second surface in a back contact battery provided by an embodiment of the present disclosure;

[0023] Figure 4 A partial structural schematic diagram of the projection of a first electrical contact point, a first electrode, and an isolation portion on the second surface in a back contact battery provided by an embodiment of the present disclosure;

[0024] Figure 5 A partial structural schematic diagram of the projection of a second electrical contact point, a second electrode, and an isolation portion on the second surface in a back contact battery provided by an embodiment of the present disclosure;

[0025] Figure 6A partial perspective view of a cell string in a photovoltaic module according to an embodiment of the present disclosure is provided.

[0026] Figure 7 A cross-sectional view of a photovoltaic module according to an embodiment of the present disclosure is provided.

[0027] Legend of reference signs:

[0028] 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, encapsulant film; 22, cover plate; 23, solder ribbon. DETAILED DESCRIPTION

[0029] As can be known from the background, in the process of sending the cell after printing the metal electrode to the module end to assemble to form the module, multiple back contact cells are usually stacked and arranged. The back surface of one back contact cell directly contacts the front surface of another back contact cell, and the metal electrode of the back surface of one back contact cell damages the passivation layer of the front surface of another back contact cell, resulting in a decrease in the passivation effect of the passivation layer and poor performance of the back contact cell.

[0030] The embodiments of the present disclosure provide 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 avoid the direct contact of another back contact cell with the first passivation layer on one back contact cell, and avoid the damage of the first passivation layer by another back contact cell, so as to ensure the passivation effect of the first passivation layer and improve the performance of the back contact cell.

[0031] 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 cell is stacked on the first surface of one back contact cell, the direct contact of the isolation portion on one back contact cell with the first electrode and the second electrode of another back contact cell can be avoided, so as to avoid the case that the overall height of the stacked back contact cells is high and the structure of the stacked back contact cells is unstable. In addition, the force between the stacked back contact cells can be avoided from being concentrated on the first electrode and the second electrode, so as to avoid the damage of the first electrode and the second electrode and the decrease in the performance of the back contact cell. That is, the first electrode and the second electrode can be protected, and the performance of the back contact cell can be improved.

[0032] In the description of the embodiments of the disclosure, the technical terms "first", "second", and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the disclosure, the meaning of "multiple" is more than two, unless otherwise explicitly specified and limited.

[0033] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily a separate or alternative embodiment to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0034] In the description of the embodiments of the disclosure, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can mean: A exists, A and B exist, and B exists. In addition, the character " / " herein generally represents an "or" relationship between the front and rear associated objects.

[0035] In the description of the embodiments of the disclosure, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0036] In the description of the embodiments of the disclosure, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the disclosure and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the embodiments of the disclosure.

[0037] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing", and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the disclosure can be understood according to the specific circumstances.

[0038] In the drawings corresponding to the embodiments of the present disclosure, the thickness and area of a layer are exaggerated for clarity. When one component (such as a layer, film, region, or substrate) is described as being "on" or "at" another component, it can be "directly" on or at the other component, or there can be a third component between the two components. Conversely, when one component is described as being "formed on" or "formed at" another component, or a component surface is formed or provided with another component, it means that there is no third component between the two components. In addition, when one component is described as being "formed substantially 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.

[0039] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, it does not exclude the presence of other components, and other components can also be further included. In addition, when a layer, film, region, or plate, etc. component is referred to as "on / over" another component, it can be "directly on" another component (i.e. between the other component surface and another component without other components), or another component can be present therebetween. In addition, when a layer, film, region, plate, etc. component is "directly on" another component, or when a layer, film, region, plate, etc. component is on another component surface, it means that there is no other component therebetween.

[0040] The embodiments of the present disclosure will be described in detail below with reference to the drawings. However, those of ordinary skill in the art can understand that, in the embodiments of the present disclosure, many technical details are presented in order to make the reader better understand the present disclosure. However, the technical solutions claimed by the present disclosure can be implemented even without these technical details and based on various changes and modifications of the following embodiments.

[0041] Figure 1 A structural schematic diagram of a back contact cell provided by an embodiment of the present disclosure.

[0042] Reference Figure 1The back contact cell comprises 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 comprises a first surface 110 and a second surface 120 opposite to each other, the second surface 120 comprises a first region 130 and a second region 140 arranged alternately and spaced apart, and a spacing region 150 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 arranged spaced apart on the surface of the first passivation layer 101 away from the substrate 100; the first doped conductive layer 103 is located on the first region 130, and the second doped conductive layer 104 is located on the second region 140, the doping elements in the first doped conductive layer 103 and the doping elements in the second doped conductive layer 104 have different conductive types; the first electrode 105 is located on the second surface 120 and in electrical contact with the first doped conductive layer 103; and the second electrode 106 is located on the second surface 120 and in electrical contact with the second doped conductive layer 104. 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.

[0043] Figure 2 A structural schematic diagram of two stacked back contact cells is provided for the embodiments of the present disclosure.

[0044] It should be noted that, Figure 2 In order to better distinguish and clearly illustrate the two stacked back contact cells 10, one back contact cell is defined as a first back contact cell 10a, and the other back contact cell is defined as a second back contact cell 10b. Wherein, the other back contact cell is stacked directly above the one back contact cell means that the second back contact cell 10b is stacked directly above the first back contact cell 10a.

[0045] For reference Figure 1 And Figure 2 A plurality of isolation portions 102 are arranged on the surface of the first passivation layer 101 away from the substrate 100, when the second back contact cell 10b is stacked on the first surface 110 of the first back contact cell 10a, the isolation portion 102 can avoid the second back contact cell 10b directly contacting the first passivation layer 101 on the first back contact cell 10a, and avoid the first passivation layer 101 being scratched by the second back contact cell 10b, so as to ensure the passivation effect of the first passivation layer 101 and improve the performance of the back contact cell 10.

[0046] In addition, the projection of the isolation portion 102 on the second surface 120 is spaced apart from the projection of the first electrode 105 on the second surface 120, and the projection of the isolation portion 102 on the second surface 120 is spaced apart from the 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 avoid the isolation portion 102 on the first back contact battery 10a directly contacting the first electrode 105 and the second electrode 106 of the second back contact battery 10b, on the one hand, which can avoid the isolation portion 102 lifting the first electrode 105 and the second electrode 106 of the second back contact battery 10b, resulting in the overall height of the stacked back contact battery 10 being too high and the structure of the stacked back contact battery 10 being unstable, that is, which can improve the structural stability of the stacked back contact battery 10. On the other hand, it can avoid the force between the stacked back contact batteries 10 concentrating on the first electrode 105 and the second electrode 106, thereby avoiding damaging the first electrode 105 and the second electrode 106 and reducing the performance of the back contact battery 10, that is, which can protect the first electrode 105 and the second electrode 106, thereby improving the performance of the back contact battery 10.

[0047] It should be noted that when the first back contact battery 10a and the second back contact battery 10b are stacked, in order to make the stacked back contact battery 10 neat, the first surface 110 of the first back contact battery 10a is usually placed opposite the second surface 120 of the second back contact battery 10b. That is, the projection of the first surface 110 of the first back contact battery 10a on the ground coincides with the projection of the second surface 120 of the second back contact battery 10b on the ground. In addition, the projection of the isolation portion 102 on the second surface 120 is spaced apart from the projection of the first electrode 105 on the second surface 120, and the projection of the isolation portion 102 on the second surface 120 is spaced apart from the 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.

[0048] In some embodiments, the back contact battery 10 can be an IBC battery, an HPBC (Hybrid Passivated Back Contact) battery, a TBC battery superimposed with TOPCON technology and IBC technology, or an HBC battery superimposed with HIT / HJT (Heterojunction Technology) technology and IBC technology, and of course can also be other types of back contact batteries.

[0049] The substrate 100 is configured to receive incident light and generate photo-generated carriers. In some embodiments, the substrate 100 can be a semiconductor substrate 100.

[0050] In some embodiments, the material of the substrate 100 can be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, for example, can be silicon or germanium. Among them, the elemental semiconductor material can be single-crystalline, polycrystalline, amorphous or microcrystalline (a state having both single-crystalline and amorphous, referred to as microcrystalline), for example, silicon can be at least one of single-crystalline silicon, polycrystalline silicon, amorphous silicon or microcrystalline silicon.

[0051] In some embodiments, the material of the substrate 100 can also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenium and the like.

[0052] The substrate 100 can also be a sapphire substrate, a silicon-on-insulator substrate or a germanium-on-insulator substrate.

[0053] The substrate 100 can 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, which can be at least one of a group V element such as phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element or arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, which can be at least one of a group III element such as boron (B) element, aluminum (Al) element, gallium (Ga) element or indium (In) element.

[0054] The substrate 100 has a first face 110 and a second face 120 opposite to each other. In some embodiments, the back contact cell 10 is a single-sided cell, and the first face 110 of the substrate 100 can be used as a light-receiving face to receive incident light, and the second face 120 can be used as a back light-receiving face. In some embodiments, the back contact cell is a double-sided cell, and both the first face and the second face of the substrate can be used as light-receiving faces to receive incident light. It can be understood that the back light-receiving face as referred to in the embodiments of the present application can also receive incident light, but the receiving degree of the incident light is weaker than that of the light-receiving face, and thus is defined as a back light-receiving face.

[0055] 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, so that the absorption efficiency of the first surface 110 and the second surface 120 of the substrate 100 to the incident light can be enhanced. In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, the pyramid textured surface can not only reduce the reflectivity of the surface of the substrate 100, but also form a light trap to enhance the absorption effect of the substrate 100 to the incident light and improve the photoelectric conversion efficiency of the back contact cell 10.

[0056] Specifically, if the back contact cell 10 is a single-sided cell, a textured surface, for example, a pyramid textured surface, can be formed on the light-receiving surface of the substrate 100, and the back surface of the substrate 100 can be a polished surface, i.e., the back surface of the substrate 100 is flatter than the light-receiving surface. It should be noted that for a single-sided cell, a textured surface can also be formed on both the light-receiving surface and the back surface of the substrate 100.

[0057] If the back contact cell is a double-sided cell, a textured surface can be formed on both the light-receiving surface and the back surface of the substrate.

[0058] The first passivation layer 101 is located on the first surface 110 and is used to passivate the substrate 100 to reduce the interface state density and improve the performance of the back contact cell 10.

[0059] 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 silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0060] The first region 130 is a region where the orthographic projection of the first doped conductive layer 103 on the second surface 120 is located, the second region 140 is a region where the orthographic projection of the second doped conductive layer 104 on the second surface 120 is located, and the interval region 150 is located between the first region 130 and the second region 140.

[0061] 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 the P-type doping element and the N-type doping element.

[0062] The material of the first doped conductive layer 103 can be at least one of amorphous silicon, silicon carbide, microcrystalline silicon, or polycrystalline silicon.

[0063] The material of the second doped conductive layer 104 can be at least one of amorphous silicon, silicon carbide, microcrystalline silicon, or polycrystalline silicon.

[0064] The first electrode 105 is in electrical contact with the first doped conductive layer 103 for transmitting the current collected by the first doped conductive layer 103.

[0065] The second electrode 106 is in electrical contact with the second doped conductive layer 104 for transmitting the current collected by the second doped conductive layer 104.

[0066] In some embodiments, the back contact cell 10 can further comprise a second passivation layer 107, which is located on the surface of the first doped conductive layer 103 and the second doped conductive layer 104 away from the substrate 100, and is also located on the spacer 150. The thickness of the spacer 102 is a first thickness T, the height of the first electrode 105 away from the surface of the substrate 100 is a first height H1, the height of the second electrode 106 away from the surface of the substrate 100 is a second height H2, and the back contact cell 10 satisfies H1≥H2 and 1.5H1≤T≤10H1. The first thickness T in the above range can ensure that the first electrode 105 and the second electrode 106 do not contact the first passivation layer 101 of the second back contact cell 10b, so as not to damage the first passivation layer 101 of the second back contact cell 10b, and can also avoid affecting the absorption of sunlight by the back contact cell 10 due to the too thick thickness of the spacer 102.

[0067] 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 cell 10.

[0068] The second passivation layer 107 can comprise a single-layer film layer structure or a stacked film layer structure, and the material of the second passivation layer 107 can comprise any one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon carbon oxynitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0069] In some embodiments, the first height H1 is 5μm~11μm, for example, 5μm~7μm, 7μm~9μm, or 9μm~11μm. For example, the first height H1 can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, or 11μm.

[0070] In some embodiments, the second height H2 is 3μm~9μm, for example, 3μm~5μm, 5μm~7μm, or 7μm~9μm. For example, the second height H2 can be 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, or 9μm.

[0071] In some embodiments, the first thickness T is 7 μm to 50 μm, for example, 7 μm to 15 μm, 15 μm to 25 μm, 25 μm to 35 μm, or 35 μm to 50 μm. For example, the first thickness T can be 7 μm, 11 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, or 50 μm. The first thickness T in the above range can ensure that the first electrode 105 and the second electrode 106 do not contact and damage the first passivation layer 101 of the second back contact cell 10b, and can also avoid affecting the absorption of sunlight by the back contact cell 10 due to the excessive thickness of the isolation portion 102.

[0072] Figure 3 A structural schematic diagram of a back contact cell provided by an embodiment of the present disclosure is shown.

[0073] It should be noted that, Figure 3 The projection of the isolation portion on the second face is circular in the above embodiment. In fact, the shape of the projection of the isolation portion on the second face can also be any shape such as a rectangle, a triangle, a polygon, etc.

[0074] Reference is made to Figure 2 and Figure 3 In some embodiments, the distance between any two adjacent isolation portions 102 along the first direction X is the same, and the distance between any two adjacent isolation portions 102 along the second direction Y is the same. In this way, the isolation portions 102 are evenly distributed on the first face 110, and the isolation portions 102 can provide uniform support force for other back contact cells 10 (for example, the second back contact cell 10b) stacked above the isolation portions 102, which is beneficial to improve the stability of the stacked back contact cells 10.

[0075] In the above embodiments, the distance between the two adjacent isolation portions 102 along the first direction X is the straight-line distance between the geometric centers of the two adjacent isolation portions 102 along the first direction X, and the distance between the two adjacent isolation portions 102 along the second direction Y is the straight-line distance between the geometric centers of the two adjacent isolation portions 102 along the second direction Y.

[0076] The first direction X and the second direction Y can be perpendicular to each other.

[0077] In some embodiments, any two adjacent isolation portions 102 have a distance of 3mm to 10mm along the first direction X, such as 3mm to 5mm, 5mm to 8mm, or 8mm to 10mm. For example, any two adjacent isolation portions 102 can have a distance of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm along the first direction X. When the distance between any two adjacent isolation portions 102 along the first direction X is within the above range, the isolation portions 102 can provide sufficient support for other back contact cells 10 stacked above the isolation portions 102, and can also avoid the situation that the distance between adjacent isolation portions 102 along the first direction X is too close, the number of isolation portions 102 is too large, and the back contact cell 10 cannot absorb sunlight.

[0078] Any two adjacent isolation portions 102 have a distance of 3mm to 10mm along the second direction Y, such as 3mm to 5mm, 5mm to 8mm, or 8mm to 10mm. For example, any two adjacent isolation portions 102 can have a distance of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm along the second direction Y. When the distance between any two adjacent isolation portions 102 along the second direction Y is within the above range, the isolation portions 102 can provide sufficient support for other back contact cells 10 stacked above the isolation portions 102, and can also avoid the situation that the distance between adjacent isolation portions 102 along the second direction Y is too close, the number of isolation portions 102 is too large, and the back contact cell 10 cannot absorb sunlight.

[0079] In some embodiments, the ratio of the total area of the projection of the plurality of 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 projection of the plurality of isolation portions 102 on the second surface 120 to the area of the second surface 120 is within the above range, it can avoid the situation that the total area of the projection of the isolation portions 102 on the second surface 120 is too small, and the isolation portions 102 cannot provide sufficient support for other back contact cells 10 stacked above the isolation portions 102 (for example, the isolation portions 102 on the first back contact cell 10a provide sufficient support for the second back contact cell 10b), and can also avoid the situation that the area of the projection of the isolation portions 102 on the second surface 120 is too large, and the back contact cell 10 cannot absorb sunlight.

[0080] In some embodiments, the area of the projection of a single isolation portion 102 on the second surface 120 is 0.01mm 2 to 80mm 2 . For example, the area of the projection of a single isolation portion 102 on the second surface 120 can be 0.01mm 2 to 1mm 2 , 1mm 2 to 20mm 220mm 2 40mm 2 40mm 2 60mm 2 60mm 2 80mm 2 For example, the single isolation portion 102 can have a projected area on the second surface 120 of 0.01mm 2 0.05mm 2 0.1mm 2 0.5mm 2 1mm 2 5mm 2 10mm 2 15mm 2 20mm 2 30mm 2 40mm 2 50mm 2 60mm 2 70mm 2 or 80mm 2 The projected area of the single isolation portion 102 on the second surface 120 can be within the above range to avoid the situation that the projected area of the single isolation portion 102 is too small to provide sufficient support for the other back contact cells 10 stacked above the isolation portion 102, and to avoid the situation that the projected area of the single isolation portion 102 is too large to cause the back contact cell 10 to have a large light shielding area, resulting in a large optical loss of the cell.

[0081] In some embodiments, the total projected area of the plurality of isolation portions 102 on the second surface 120 is 300mm 2 1700mm 2 For example, the total projected area of the plurality of isolation portions 102 on the second surface 120 can be 300mm 2 700mm 2 700mm 2 1100mm 2 1100mm 2 1400mm 2 1400mm 2 1700mm 2 For example, the total projected area of the plurality of isolation portions 102 on the second surface 120 can be 300mm 2 500mm 2 700mm 2 900mm 2 1000mm 2 1100mm 2 1250mm 2 1400mm 21550mm 2 or 1700mm 2 The total area of the projection of the plurality of isolation portions 102 on the second surface 120 is within the above range, which can avoid the situation that the total area of the projection of the plurality of isolation portions 102 on the second surface 120 is too small, and the single isolation portion 102 is difficult to provide sufficient support force for the other back contact cells 10 stacked above the isolation portion 102, and can also avoid the situation that the total area of the projection of the plurality of isolation portions 102 on the second surface 120 is too large, causing the light shielding area of the back contact cell 10 to be too large, resulting in more optical loss of the cell.

[0082] In some embodiments, the isolation portion 102 is composed of a transparent material. In this way, the first surface 110 can absorb more sunlight, which is beneficial to improve the performance of the back contact cell 10.

[0083] In some embodiments, the material of the isolation portion 102 can be one or a combination of acrylic resin, epoxy resin, polyurethane, and silicone. The acrylic resin, epoxy resin, polyurethane, and silicone of the glue system have high transparency, good light and color preservation, and water and chemical resistance, low cost, and are not easy to cause damage to the first passivation layer 101 on the first surface 110 and other back contact cells 10 in contact with the isolation portion 102, further reducing optical loss and saving cost.

[0084] In some embodiments, the projection of the isolation portion 102 on the second surface 120 is located in the spacing area 150. In this way, when the first back contact cell 10a and the second back contact cell 10b are stacked, and the first surface 110 of the first back contact cell 10a and the second surface 120 of the second back contact cell 10b are placed opposite to each other, the isolation portion 102 of the first back contact cell 10a is in contact with the second passivation layer 107 on the spacing area 150 of the second back contact cell 10b, which can avoid the situation that the top of the isolation portion 102 contacts the second passivation layer 107 of the second back contact cell 10b, and the isolation portion 102 contacts the first doped conductive layer 103 or the second doped conductive layer 104 of the second back contact cell 10b, resulting in the height of the film layer contacted by the top of the isolation portion 102 relative to the first surface 110 is not uniform, causing the inclination of the stacked back contact cell 10. That is, the isolation portion 102 of the first back contact cell 10a is in contact with the second passivation layer 107 on the spacing area 150 of the second back contact cell 10b, which can ensure that the height of the film layer contacted by the top of the plurality of isolation portions 102 relative to the first surface 110 is as uniform as possible, which is beneficial to improve the structural stability of the stacked back contact cell 10.

[0085] Figure 4A partial structural schematic diagram of the orthographic 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 orthographic 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.

[0086] Reference Figure 2 , Figure 4 and Figure 5 In some embodiments, the back contact battery 10 further comprises: 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 orthographic projection of the plurality of isolation parts 102 on the second surface 120 is symmetrically distributed about the geometric center of the orthographic 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 orthographic projection of the plurality of isolation parts 102 on the second surface 120 is symmetrically distributed about the geometric center of the orthographic projection of the second electrical contact point 109 on the second surface 120.

[0087] The first electrical contact point 108 is in electrical contact with the first electrode 105, which provides a soldering position for the connection of the solder strip and the back contact battery 10 when the solder strip connects a plurality of back contact batteries 10 to form a battery string.

[0088] The second electrical contact point 109 is in electrical contact with the second electrode 106, which provides a soldering position for the connection of the solder strip and the back contact battery 10 when the solder strip connects a plurality of back contact batteries 10 to form a battery string.

[0089] In some embodiments, the first electrode 105 comprises 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.

[0090] The second electrode 106 comprises 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.

[0091] The first electrical contact point 108 is located at the intersection 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 can coincide with the intersection connection point of the first main grid 115 and the first fine grid 125.

[0092] The second electrical contact point 109 is located at the intersection of the second major grid 116 and the second fine grid 126 of the second electrode 106, and the geometric center of the second electrical contact point 109 can coincide with the intersection connection point of the second major grid 116 and the second fine grid 126.

[0093] It should be noted that, Figure 2 In the first electrode is a first fine grid, and the second electrode is a second fine grid, and Figure 2 In the first major grid and the second major grid are not shown. In addition, Figure 2 In order to clearly show the first height H1 and the second height H2, the height of the surface of the first fine grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate is shown as the first height H1, and the height of the surface of the second fine grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate is shown as the second height H2. In fact, the first height H1 can also be the height of the surface of the first major grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate, and the second height H2 can also be the height of the surface of the second major grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate. Specifically, if the surface of the first fine grid away from the substrate is higher than the surface of the first major grid away from the substrate, the first height H1 is the height of the surface of the first fine grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate; if the surface of the first major grid away from the substrate is higher than the surface of the first fine grid away from the substrate, the first height H1 is the height of the surface of the first major grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate. If the surface of the second fine grid away from the substrate is higher than the surface of the second major grid away from the substrate, the second height H2 is the height of the surface of the second fine grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate; if the surface of the second major grid away from the substrate is higher than the surface of the second fine grid away from the substrate, the second height H2 is the height of the surface of the first major grid away from the substrate relative to the surface of the passivation layer on the interval away from the substrate.

[0094] In addition, the performance of the back contact battery 10 can be tested by the probe of the testing device contacting the first electrical contact point 108 and the second electrical contact point 109. When testing using the testing device, the testing device will provide a pressing plate above the first surface 110 of the back contact battery 10, the pressing plate will be in direct contact with the isolation portions 102 to exert a downward force on the isolation portions 102, so that the probe of the testing device is 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 projection of the plurality of isolation portions 102 on the second surface 120 is symmetrically distributed about the geometric center of the projection of the first electrical contact point 108 on the second surface 120, so that when the back contact battery 10 is tested, the first surface 110 of the back contact battery 10 can be balanced by the force of the pressing plate on the isolation portions 102 and the force of the probe on the second surface 120 of the back contact battery 10 on the first electrical contact point 108, so that the first surface 110 of the back contact battery 10 can be uniformly stressed, avoiding the situation that the battery is broken or hidden due to stress concentration. Similarly, the projection of the plurality of isolation portions 102 on the second surface 120 is symmetrically distributed about the geometric center of the projection of the second electrical contact point 109 on the second surface 120, so that when the back contact battery 10 is tested, the first surface 110 of the back contact battery 10 can be balanced by the force of the pressing plate on the isolation portions 102 and the force of the probe on the second surface 120 of the back contact battery 10 on the second electrical contact point 109, so that the first surface 110 of the back contact battery 10 can be uniformly stressed, also avoiding the situation that the battery is broken or hidden due to stress concentration.

[0095] In some embodiments, with reference to Figure 2 and Figure 4 , the distance D1 between the geometric center of the projection of the first electrical contact point 108 on the second surface 120 and the geometric center of the projection of the adjacent isolation portion 102 on the second surface 120 is 2mm-8mm; for example, 2mm-4mm, 4mm-6mm, or 6mm-8mm. For example, the distance D1 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, or 8mm. When the pressing plate of the testing device exerts pressure on the isolation portions 102, allowing the probe of the testing device to contact the first electrical contact point 108 on the second surface 120, if the distance D1 is too large, the isolation portions 102 will be difficult to provide effective support force, so that the back contact battery 10 will be broken or hidden under the action of the pressing plate; if the distance D1 is too small, the projection of the isolation portions 102 on the second surface 120 will partially coincide with the projection of the first electrode 105 on the second surface 120. In other words, when the distance D1 is within the above range, the isolation portions 102 can provide sufficient support force to balance the action of the pressing plate on the first surface 110 of the back contact battery 10, and can also avoid the projection of the isolation portions 102 on the second surface 120 partially coinciding with the projection of the first electrode 105 on the second surface 120.

[0096] Reference is made to Figure 2 and Figure 5 The distance D2 between the geometric center of the orthographic projection of the second electrical contact point 109 on the second surface 120 and the geometric center of the orthographic projection of the adjacent isolation portion 102 on the second surface 120 is 2mm-8mm, for example, 2mm-4mm, 4mm-6mm, or 6mm-8mm. For example, the distance D2 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, or 8mm.

[0097] When the pressing plate of the testing device exerts pressure on the isolation portion 102, and the probe of the testing device contacts the second electrical contact point 109 on the second surface 120, if the distance D2 is too large, the isolation portion 102 is difficult to provide effective support force, so that the back contact battery 10 is broken or cracked under the action of the pressing plate; if the distance D2 is too small, the orthographic projection of the isolation portion 102 on the second surface 120 is at risk of overlapping with the orthographic 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 portion 102 can provide sufficient support force to balance the action 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 portion 102 on the second surface 120 overlapping with the orthographic projection of the second electrode 106 on the second surface 120.

[0098] Some embodiments of the present disclosure also provide a photovoltaic module, which can include the back contact battery in any of the embodiments. It should be noted that the same or corresponding parts as the above embodiments can refer to the above embodiments, which will not be described hereinafter.

[0099] Figure 6 A partial perspective structure schematic diagram of a cell string in a photovoltaic module provided by an embodiment of the present disclosure, Figure 7 A cross-sectional structure schematic diagram of a photovoltaic module provided by an embodiment of the present disclosure.

[0100] Reference is made to Figure 6 and Figure 7 The photovoltaic module includes a cell string, which is connected by a plurality of back contact batteries 10 as in any of the above embodiments. The photovoltaic module further includes an encapsulation film 21 and a cover plate 22, the encapsulation film 21 is used to cover the surface of the cell string, and the cover plate 22 is used to cover the surface of the encapsulation film 21 away from the cell string.

[0101] In some embodiments, every two adjacent back contact batteries 10 in the plurality of back contact batteries 10 can be electrically connected by a solder strip 23.

[0102] In some embodiments, the encapsulation film 21 comprises a first encapsulation layer covering one of the first and second surfaces of the back contact battery 10 and a second encapsulation layer covering the other of the first and second surfaces of the back contact battery 10. Specifically, at least one of the first and second encapsulation layers can be an organic encapsulation film such as a polyvinyl butyral (PVB) film, an ethylene-vinyl acetate (EVA) film, a polyolefin elastomer (POE) film, or a polyethylene terephthalate (PET) film, or at least one of the first and second encapsulation layers can also be an EP film, an EPE film, or a PVP film. The EP film refers to a co-extruded film formed by stacking an EVA film and a POE film, the EPE film refers to a co-extruded film formed by stacking an EVA film, a POE film, and an EVA film in sequence, and the PVP film refers to a co-extruded film formed by stacking a POE film, an EVA film, and a POE film in sequence. The co-extruded film can be prepared by extruding one or more raw materials onto another film that has been prepared or by bonding different types of films to each other during film processing.

[0103] In some cases, the first encapsulation layer and the second encapsulation layer have a boundary before lamination, and after lamination, the photovoltaic module is formed without the concept of the first encapsulation layer and the second encapsulation layer, i.e., the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film 21.

[0104] In some embodiments, the cover plate 22 can be a glass cover plate, a plastic cover plate, or the like having a light-transmitting function. Specifically, the surface of the cover plate 22 facing the encapsulation film 21 can be a concave-convex surface or a suede surface comprising a plurality of convex structures, thereby increasing the utilization rate of incident light. The cover plate 22 comprises a first cover plate opposite the first encapsulation layer and a second cover plate opposite the second encapsulation layer.

[0105] It is to be understood that the above-described embodiments are merely illustrative of the principles of the present disclosure and that numerous and varied embodiments can be derived from it without departing from the spirit of the present disclosure. Any skilled person in the art, without departing from the spirit and scope of the present disclosure, can make various modifications and changes, and 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, include: The substrate includes a first surface and a second surface opposite to each other, the second surface including an alternating and spaced-apart first region and a second region, and a spacer region located between the first region and the second region; A first passivation layer is located on the first surface; Multiple isolation portions are spaced apart on the surface of the first passivation layer opposite to the substrate; A first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer is located on the first region and 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 conductivity types. A first electrode is located on the second surface and is in electrical contact with the first doped conductive layer. The second electrode is located on the second surface and is in electrical contact with the second doped conductive layer. A second passivation layer is located on the surface of the first doped conductive layer and the second doped conductive layer away from the substrate, and the second passivation layer is also located on the spacer region. Wherein, the orthographic projection of the isolation portion on the second surface is located within the interval region, the thickness of the isolation portion is a first thickness T, with the surface of the second passivation layer on the interval region facing away from the substrate as a reference, the height of the first electrode facing away from the substrate is a first height H1, the height 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.

2. The back contact battery according to claim 1, characterized in that, The first height H1 is 5μm~11μm; the second height H2 is 3μm~9μm; and the first thickness T is 7μm~50μm.

3. The back contact battery according to claim 1, characterized in that, Any two adjacent isolation sections are equidistant along the first direction, and any two adjacent isolation sections are equidistant along the second direction.

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

5. The back contact battery according to claim 1, characterized in that, The back contact battery also includes: The first electrical contact point is in electrical contact with the first electrode, and the orthographic projections of the plurality of isolation portions 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. The second electrical contact point is in electrical contact with the second electrode, and the orthographic projections of the plurality of isolation portions 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.

6. The back contact battery according to claim 5, characterized in that, The distance between the geometric center of the first electrical contact point's orthographic projection on the second surface and the geometric center of the adjacent isolation portion's orthographic projection on the second surface is 2mm to 8mm; the distance between the geometric center of the second electrical contact point's orthographic projection on the second surface and the geometric center of the adjacent isolation portion's orthographic projection on the second surface is 2mm to 8mm.

7. The back contact battery according to claim 1, characterized in that, The ratio of the total area of ​​the orthographic projection of the plurality of isolation portions on the second surface to the area of ​​the second surface is 0.01 to 0.

05.

8. The back contact battery according to claim 1, characterized in that, The isolation section is made of transparent material.

9. A photovoltaic module, characterized in that, include: A battery string is formed by connecting multiple back-contact batteries as described in any one of claims 1 to 8; An encapsulating film, the encapsulating film being used to cover the surface of the battery string; A cover plate for covering the surface of the encapsulating film facing away from the battery string.

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