Back contact battery and photovoltaic module

Abstract

The embodiment of the invention relates to the photovoltaic field, and provides a back contact battery and a photovoltaic module, and the back contact battery comprises a substrate with a first edge; the first doped conductive layers and the second doped conductive layers are alternately distributed on the second surface of the substrate; the first grid lines and the second grid lines are alternately arranged in the first direction; the first connecting lines and the second connecting lines are alternately arranged in the second direction, the first connecting lines are electrically connected with the first grid lines, the first connecting lines comprise edge connecting lines and middle connecting lines, welding parts are not arranged on the edge connecting lines, the second connecting lines adjacent to the edge connecting lines comprise function parts and interval parts, and the function parts are connected with the second grid lines; one end of the connecting structure is electrically connected with the edge connecting line, and the other end passes through the spacing part and is electrically connected with the middle connecting line adjacent to the edge connecting line. According to the embodiment of the invention, the performance of the back contact battery and the yield of the photovoltaic module can be improved at least.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the photovoltaic field, and in particular to a back-contact cell and a photovoltaic module. Background Art

[0002] At present, with the gradual depletion of fossil energy, solar cells are becoming more and more widely used as a new energy alternative. Solar cells are devices that convert sunlight into electrical energy. Solar cells use the photovoltaic principle to generate carriers, and then use electrodes to lead the carriers out, thereby facilitating the effective use of electrical energy.

[0003] Current photovoltaic cells mainly include BC cells (back contact cells, Back Contact), TOPCON (Tunnel Oxide Passivated Contact) cells, PERC cells (passivated emitter and real cell) and heterojunction cells.

[0004] However, there is a risk of cracking at the edge of the back contact cell in the related art, resulting in a low yield of the photovoltaic module. Summary of the invention

[0005] The embodiments of the present disclosure provide a back-contact cell and a photovoltaic module, which at least improve the performance of the back-contact cell and the yield of the photovoltaic module.

[0006] According to some embodiments of the present disclosure, on the one hand, an embodiment of the present disclosure provides a back-contact battery, comprising: a substrate, the substrate having a first surface and a second surface opposite to each other, the second surface having a first edge; a first doped conductive layer and a second doped conductive layer, the first doped conductive layer and the second doped conductive layer being alternately distributed on the second surface, the doped element in the first doped conductive layer and the doped element in the second doped conductive layer having a different conductivity type; first gate lines and second gate lines alternately arranged along a first direction, at least part of the first gate lines being in electrical contact with the first doped conductive layer, and at least part of the second gate lines being in electrical contact with the second doped conductive layer; first connecting lines and second connecting lines alternately arranged along a second direction, the first connecting lines being electrically connected to the first gate lines, and the first connecting lines being electrically connected to the first gate lines. It includes an edge connection line and an intermediate connection line, the edge connection line is not provided with a welding portion, the second connection line adjacent to the edge connection line includes a functional portion and a spacing portion, the functional portion is connected to the second gate line; a connection structure, one end of the connection structure is electrically connected to the edge connection line, and the other end passes through the spacing portion to be electrically connected to the intermediate connection line adjacent to the edge connection line; wherein the first gate line electrically connected to the intermediate connection line includes two first main body portions spaced apart and a first connection portion connecting the two first main body portions, the first connection portion is not electrically in contact with the first doped conductive layer, and the second gate line includes two second main body portions spaced apart and a second connection portion connecting the two second main body portions, the second connection portion is not electrically in contact with the second doped conductive layer.

[0007] In some embodiments, the functional portion includes a first portion adjacent to the connection structure, and a second portion connected to the first portion; along the second direction, a width of the first portion is greater than a width of the second portion.

[0008] In some embodiments, along the second direction, the width of the first portion is 0.02 mm to 0.1 mm, and the width of the second portion is 0.01 mm to 0.05 mm.

[0009] In some embodiments, in the first direction, the first connecting portion is electrically connected to the first connecting line, the second connecting portion is electrically connected to the second connecting line, the width of the first connecting portion is greater than the width of the first main body portion, and the width of the second connecting portion is greater than the width of the second main body portion.

[0010] In some embodiments, along the first direction, the width of the first connecting portion is 0.02mm-0.1mm, the width of the first main body portion is 0.01mm-0.05mm, the width of the second connecting portion is 0.02mm-0.1mm, and the width of the second main body portion is 0.01mm-0.05mm.

[0011] In some embodiments, along the second direction, the distance between the edge connection line and the adjacent second connection line is a first spacing, the distance between the second connection line adjacent to the edge connection line and the adjacent middle connection line is a second spacing, and the first spacing is smaller than the second spacing.

[0012] In some embodiments, the first spacing is 0.5 mm to 1.5 mm, and the second spacing is 0.7 mm to 2.0 mm.

[0013] In some embodiments, the back-contact battery also includes: a first solder pad, the first solder pad is located at the junction of a portion of the first connecting line and the first gate line, and is electrically connected to the first connecting line and the first gate line; a second solder pad, the second solder pad is located at the junction of a portion of the second connecting line and the second gate line, and is electrically connected to the second connecting line and the second gate line; the second surface also includes a third edge connected to the first edge, along the first direction, the first solder pad adjacent to the third edge is spaced apart from the first gate line adjacent to the third edge, and the second solder pad adjacent to the third edge is spaced apart from the first gate line adjacent to the third edge.

[0014] In some embodiments, the distance between the first pad adjacent to the third edge and the first gate line adjacent to the third edge is 5 mm to 15 mm, and the distance between the second pad adjacent to the third edge and the first gate line adjacent to the third edge is 5 mm to 15 mm.

[0015] According to some embodiments of the present disclosure, on the other hand, the embodiments of the present disclosure further provide a photovoltaic module, including a cell string, which is formed by connecting a plurality of back-contact cells as described in any of the above embodiments; a welding strip, which is used to connect adjacent back-contact cells; a packaging film, which is used to cover the surface of the cell string; and a cover plate, which is used to cover the surface of the packaging film away from the cell string.

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

[0017] In the above-mentioned back-contact battery, one end of the connection structure is electrically connected to the edge connection line, and the other end is electrically connected to the middle connection line adjacent to the edge connection line through the spacer. The middle connection line adjacent to the edge connection collects the current collected by the edge connection line through the connection structure, so that no welding part is required on the edge connection line, thereby avoiding the problem of rupture or hidden cracks at the edge of the back contact battery due to welding stress, thereby improving the yield of the photovoltaic module.

[0018] In addition, the first gate line electrically connected to the middle connection line includes two first main body parts arranged at intervals and a first connection part connecting the two first main bodies, the first connection part is not in electrical contact with the first doped conductive layer, so that the contact area between the first gate line and the first doped conductive layer is small, thereby reducing the metal recombination between the first gate line and the first doped conductive layer, thereby improving the performance of the back contact battery. And the second gate line includes two second main body parts arranged at intervals and a second connection part connecting the two second main body parts, the second connection part is not in electrical contact with the second doped conductive layer, so that the contact area between the second gate line and the second doped conductive layer is small, thereby reducing the metal recombination between the second gate line and the second doped conductive layer, thereby improving the performance of the back contact battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings, and these exemplified descriptions do not constitute a limitation on the embodiments. Unless otherwise specified, the pictures in the drawings do not constitute a scale limitation. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the traditional technology, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 A cross-sectional view of a back contact battery provided for an embodiment of the present disclosure;

[0021] Figure 2 A schematic diagram of a first structure of a back contact battery provided in an embodiment of the present disclosure;

[0022] Figure 3 for Figure 2 A partial enlarged schematic diagram of part A;

[0023] Figure 4 A second schematic diagram of the structure of a back contact battery provided for the implementation of the present disclosure;

[0024] Figure 5 A third structural schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0025] Figure 6 for Figure 5 A partial enlarged schematic diagram of part B;

[0026] Figure 7 A fourth structural schematic diagram of a back contact battery provided in an embodiment of the present disclosure;

[0027] Figure 8 for Figure 7 A partial enlarged schematic diagram of part C in the middle;

[0028] Fig. 9 A fifth structural schematic diagram of a back-contact battery provided in an embodiment of the present disclosure;

[0029] Fig.10 A cross-sectional view of a photovoltaic module provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0030] In the back-contact cells of the related art, soldering pads and soldering strips are provided on the grid lines at the edges of the cells. The soldering strips electrically connect multiple back-contact cells to form a cell string in the photovoltaic module. In the process of welding the soldering pads and soldering strips on the grid lines at the edges, the stress at the edges of the back-contact cells is highly concentrated, which may cause the back-contact cells to rupture, resulting in a low yield of the photovoltaic module.

[0031] Therefore, the yield rate of photovoltaic modules in the related technology needs to be improved.

[0032] In the back-contact battery provided in the embodiment of the present disclosure, one end of the connection structure is electrically connected to the edge connection line, and the other end is electrically connected to the middle connection line adjacent to the edge connection line through the spacer. The middle connection line adjacent to the edge connection collects the current collected by the edge connection line through the connection structure, so that there is no need to set a welding part (such as a welding point or a welding pad) on the edge connection line, thereby avoiding the problem of rupture or hidden cracks at the edge of the back contact battery due to welding stress, thereby improving the yield of the photovoltaic module.

[0033] On the one hand, the first gate line electrically connected to the middle connecting line includes two first main body parts arranged at intervals and a first connecting part connecting the two first main bodies, the first connecting part is not in electrical contact with the first doped conductive layer, so that the contact area between the first gate line and the first doped conductive layer is small, thereby reducing the metal recombination between the first gate line and the first doped conductive layer. On the other hand, the second gate line includes two second main body parts arranged at intervals and a second connecting part connecting the two second main body parts, the second connecting part is not in electrical contact with the second doped conductive layer, so that the contact area between the second gate line and the second doped conductive layer is small, thereby reducing the metal recombination between the second gate line and the second doped conductive layer, and the above two aspects are conducive to improving the performance of the back contact battery.

[0034] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. 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 present disclosure, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present disclosure. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0037] In the description of the embodiments of the present disclosure, the term "multiple" 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).

[0038] In the description of the embodiments of the present disclosure, the orientations or positional relationships indicated by technical terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" are based on the orientations or positional relationships shown in the accompanying drawings and are only for the convenience of describing the embodiments of the present disclosure and simplifying the description. They do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the embodiments of the present disclosure.

[0039] In the description of the embodiments of the present disclosure, unless otherwise clearly specified and limited, technical terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal connection of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0040] In the accompanying drawings corresponding to the embodiments of the present disclosure, the thickness and area of ​​the layers are magnified for better understanding and ease of description. When describing a component (such as a layer, a film, a region or a substrate) on another component or on the surface of another component, the component may be "directly" located on the surface of the other component, or a third component may be present between the two components. On the contrary, when describing a component on the surface of another component or when another component is formed or provided on the surface of a component, it means that there is no third component between the two components. In addition, when describing a component as 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.

[0041] In the description of the embodiments of the present disclosure, when a component "includes" another component, unless otherwise specified, other components are not excluded, and other components may be further included. In addition, when a component such as a layer, a film, a region, or a plate is referred to as being "on / located on" another component, it may be "directly on" the other component (i.e., located on the surface of the other component with no other components between them), or another component may exist in between. In addition, when a component such as a layer, a film, a region, a plate, etc. is "directly located on" another component, or when a component such as a layer, a film, a region, a plate, etc. is located on the surface of another component, it means that no other components are located in between.

[0042] The following will describe the various embodiments of the present disclosure in detail with reference to the accompanying drawings. However, it will be appreciated by those skilled in the art that in the various embodiments of the present disclosure, many technical details are provided in order to enable the reader to better understand the present disclosure. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present disclosure can be implemented.

[0043] Figure 1 A cross-sectional view of a back contact battery provided for an embodiment of the present disclosure; Figure 2 A schematic diagram of a first structure of a back contact battery provided in an embodiment of the present disclosure; Figure 3 for Figure 2 A partial enlarged schematic diagram of part A.

[0044] Combined with reference Figures 1 to 3The back contact battery comprises: a substrate 100, the substrate 100 having a first surface 110 and a second surface 120 opposite to each other, the second surface 120 having a first edge 130; a first doped conductive layer 101 and a second doped conductive layer 102, the first doped conductive layer 101 and the second doped conductive layer 102 being alternately distributed on the second surface 120, the doped elements in the first doped conductive layer 101 and the doped elements in the second doped conductive layer 102 having different conductivity types; first gate lines 103 and second gate lines 104 alternately arranged along a first direction X, at least part of the first gate lines 103 being in electrical contact with the first doped conductive layer 101, and at least part of the second gate lines 104 being in electrical contact with the second doped conductive layer 102; first connecting lines 105 and second connecting lines 106 alternately arranged along a second direction Y, the first connecting lines 105 being electrically connected to the first gate lines 103, the first connecting lines 105 comprising edge connecting lines 115 and middle connecting lines 116 The intermediate connection line 125, the edge connection line 115 is not provided with a welding portion, the second connection line 106 adjacent to the edge connection line 115 includes a functional portion 116 and a spacer portion 126, and the functional portion 116 is connected to the second gate line 104; the connection structure 107, one end of the connection structure 107 is electrically connected to the edge connection line 115, and the other end passes through the spacer portion 126 to be electrically connected to the intermediate connection line 125 adjacent to the edge connection line 115; wherein the first gate line 103 electrically connected to the intermediate connection line 125 includes two first main body portions 113 arranged at intervals and a first connection portion 123 connecting the two first main body portions 113, and the first connection portion 123 is not in electrical contact with the first doped conductive layer 101, and the second gate line 104 includes two second main body portions 114 arranged at intervals and a second connection portion 124 connecting the two second main body portions 114, and the second connection portion 124 is not in electrical contact with the second doped conductive layer 102.

[0045] Back-contact cells are used to absorb sunlight and convert it into electrical energy.

[0046] The substrate 100 is used to receive incident light and generate photogenerated carriers. In some embodiments, the substrate 100 may be a semiconductor substrate.

[0047] In some embodiments, the material of the substrate 100 may be an elemental semiconductor material. Specifically, the elemental semiconductor material is composed of a single element, such as silicon or germanium. The elemental semiconductor material may be in a single crystalline state, a polycrystalline state, an amorphous state, or a microcrystalline state (a state having both a single crystalline state and an amorphous state is referred to as a microcrystalline state), for example, silicon may be at least one of single crystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0048] 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 germanium, silicon carbide, gallium arsenide, indium gallium, perovskite, cadmium telluride, copper indium selenide and other materials.

[0049] The substrate 100 may also be a sapphire substrate, a silicon on insulator substrate, or a germanium on insulator substrate.

[0050] 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, which may be any one of the V-group elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type element, which may be any one of the III-group elements such as boron (B), aluminum (Al), gallium (Ga), or indium (In).

[0051] The substrate 100 has a first surface 110 and a second surface 120 that are opposite to each other.

[0052] In some embodiments, the back contact cell is a single-sided cell, then the first surface 110 of the substrate 100 can be used as a light-receiving surface for receiving incident light, and the second surface 120 can be used as a backlight surface. In some embodiments, the back contact cell is a double-sided cell, then both the first surface 110 and the second surface 120 of the substrate 100 can be used as light-receiving surfaces, 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 the incident light is weaker than the degree of receiving the incident light by the light-receiving surface, and therefore it is defined as a backlight surface.

[0053] In some embodiments, a texturing process can be performed on at least one of the first surface or the second surface of the substrate to form a velvet surface on at least one of the first surface or the second surface of the substrate. In this way, the absorption utilization rate of the first surface and the second surface of the substrate to incident light can be enhanced.

[0054] In some embodiments, the velvet surface can be a pyramid velvet surface. As a common velvet surface, the pyramid velvet surface not only reduces the reflectivity of the substrate surface, but also forms a light trap, thereby enhancing the substrate's absorption effect on incident light and improving the photoelectric conversion efficiency of the back contact battery.

[0055] Specifically, if the back contact cell is a single-sided cell, a velvet surface may be formed on the light-receiving surface of the substrate, such as a pyramid velvet surface, and the backlight surface of the substrate may be a polished surface, that is, the backlight surface of the substrate is flatter than the light-receiving surface. It should be noted that for single-sided cells, a velvet surface may also be formed on both the light-receiving surface and the backlight surface of the substrate.

[0056] If the back contact cell is a double-sided cell, a textured surface can be formed on both the light-receiving side and the backlight side of the substrate.

[0057] The first doped conductive layer 101 is doped with one of a P-type element and an N-type element, and the second doped conductive layer 102 is doped with the other of the P-type element and the N-type element.

[0058] In some embodiments, the substrate 100 is an N-type substrate, and the doping concentration of the N-type doping element in the first doped conductive layer 101 or the second doped conductive layer 102 is greater than the doping concentration of the doping element in the substrate 100, and a high-low junction is formed between the first doped conductive layer 101 or the second doped conductive layer 102 and the substrate 100, thereby enhancing the separation capability of carriers. In some embodiments, the substrate 100 is a P-type substrate, and the doping concentration of the P-type doping element in the first doped conductive layer 101 or the second doped conductive layer 102 is greater than the doping concentration of the doping element in the substrate 100, and a high-low junction is formed between the first doped conductive layer 101 or the second doped conductive layer 102 and the substrate 100, thereby enhancing the separation capability of carriers.

[0059] Among them, there may be a gap or isolation structure between the first doped conductive layer 101 and the second doped conductive layer 102 to achieve automatic isolation between different conductive type regions, which can avoid the formation of a tunnel junction between the first doped conductive layer 101 and the second doped conductive layer 102 on the second surface 120 to cause leakage and affect the battery efficiency.

[0060] At least part of the first gate line 103 is in electrical contact with the first doped conductive layer 101 , and at least part of the second gate line 104 is in electrical contact with the second doped conductive layer 102 . The first gate line 103 and the second gate line 104 are used to collect current of the back contact battery.

[0061] The first connection line 105 is in electrical contact with the first gate line 103 and is used to collect the current on the first gate line 103 .

[0062] The second connection line 106 is in electrical contact with the second gate line 104 and is used to collect the current on the second gate line 104 .

[0063] The first connection line 105 is not in electrical contact with the first doped conductive layer 101 , and the second connection line 106 is not in electrical contact with the second doped conductive layer 102 .

[0064] In some embodiments, the connection structure 107 can be electrically contacted with the first doped conductive layer 101, so that the connection structure 107 can not only realize the current transmission between the edge connection line 115 and the adjacent intermediate connection line 125, but the connection structure 107 can also collect the current on the surface of the substrate 100 by itself, thereby increasing the collection path and improving the efficiency of current collection.

[0065] In some embodiments, the connection structure 107 may not be in electrical contact with the first doped conductive layer 101 , thereby avoiding the metal recombination problem caused by the electrical contact between the connection structure 107 and the first doped conductive layer 101 , thereby improving the performance of the back contact cell.

[0066] In some embodiments, the back contact cell may further include a passivation layer (not shown), which is located on the surface of the first doped conductive layer 101 and the second doped conductive layer 102 away from the second surface 120. The passivation layer may include a single-layer film structure or a stacked-layer film structure, and the material of the passivation layer may be any one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

[0067] The first main body 113 of the first gate line 103 is in electrical contact with the first doped conductive layer 101, and the first main body 113 may penetrate the passivation layer and be in electrical contact with the first doped conductive layer 101, and the first connecting portion 123 is not in electrical contact with the first doped conductive layer 101, and at most a portion of the first connecting portion 123 may be embedded in the passivation layer and not penetrate the passivation layer, so as not to be in electrical contact with the first doped conductive layer 101. The first connecting line 105 is not in electrical contact with the first doped conductive layer 101, and at most a portion of the first connecting line 105 may be embedded in the passivation layer and not penetrate the passivation layer, so as not to be in electrical contact with the first doped conductive layer 101.

[0068] The second main body 114 of the second gate line 104 is in electrical contact with the second doped conductive layer 102, and the second main body 114 may penetrate the passivation layer and be in electrical contact with the second doped conductive layer 102, and the second connecting portion 124 is not in electrical contact with the second doped conductive layer 102, and at most a portion of the second connecting portion 124 may be embedded in the passivation layer and not penetrate the passivation layer, so as not to be in electrical contact with the second doped conductive layer 102. The second connecting line 106 is not in electrical contact with the second doped conductive layer 102, and at most a portion of the second connecting line 106 may be embedded in the passivation layer and not penetrate the passivation layer, so as not to be in electrical contact with the second doped conductive layer 102.

[0069] In some embodiments, if the sum of the first connection line 105 and the second connection line 106 is an odd number, Figure 1 and Figure 2 , the second surface 120 has two opposite first edges 130 , and the conductivity type of the edge connection line 115 corresponding to the first edge 130 of the substrate 100 is the same as the conductivity type of the first connection line 105 .

[0070] Figure 4 A second schematic diagram of the structure of a back-contact battery provided for the implementation of the present disclosure.

[0071] In some other embodiments, if the sum of the first connection line 105 and the second connection line 106 is an even number, Figure 1 and Figure 4 , the second surface 120 has a second edge 140 arranged opposite to the first edge 130, and the conductive type of the second edge connecting line 136 corresponding to the second edge 140, the conductive type of the second connecting structure 117 and the conductive type of the second connecting line 106 are all the same, then the first connecting line 105 arranged adjacent to the second edge connecting line 136 must also be designed corresponding to the above-mentioned second connecting line 106, that is, the second edge connecting line 136 close to the second edge 140 passes through the disconnection of the first connecting line 105 and is connected to the adjacent second connecting line 106.

[0072] Continue to refer Figures 1 to 3 In some embodiments, along the second direction Y, the distance between the edge connection line 115 and the adjacent second connection line 106 is a first spacing d1, and the spacing between the second connection line 106 adjacent to the edge connection line 115 and the adjacent middle connection line 125 is a second spacing d2, and the first spacing d1 is smaller than the second spacing d2. The first spacing d1 is set to be smaller, so that the length of the connection structure 107 connecting the edge connection line 115 and the adjacent middle connection line 125 can be smaller, that is, the path length of the middle connection line 125 adjacent to the edge connection line 115 collecting carriers on the edge connection line 115 can be reduced, so that the collection efficiency of the middle connection line 125 adjacent to the edge connection line 115 collecting carriers on the edge connection line 115 can be improved, and then the performance of the back contact battery can be improved.

[0073] In some embodiments, the first spacing d1 is 0.5 mm to 1.5 mm, such as 0.5 mm, 0.7 mm, 0.9 mm, 1 mm, 1.2 mm or 1.5 mm, and the second spacing d2 is 0.7 mm to 2.0 mm, such as 0.7 mm, 0.9 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2 mm. When the first spacing d1 and the second spacing d2 are within the above range, the collection efficiency of the carriers on the edge connection line 115 collected by the middle connection line 125 adjacent to the edge connection line 115 can be ensured, and the short circuit between the first connection line 105 and the second connection line 106 caused by the first spacing and the second spacing being too small can be avoided.

[0074] In some embodiments, the width of the connection structure 107 along the first direction X is greater than the width of the first gate line 103 along the first direction X. The connection structure 107 is used to connect the edge connection line 115 and the middle connection line 125, and the edge connection line 115 collects carriers of a plurality of first gate lines 103 and transmits them to the middle connection line 125 adjacent to the edge connection line 115 through the connection structure 107, so the width of the connection structure 107 needs to be set larger, so as to complete the transmission of the carriers collected by the edge connection line 115 to the middle connection line 125 adjacent to the edge connection line 115.

[0075] In some embodiments, along the first direction X, the distance between the connection structure 107 and the functional portion 116 of the adjacent second gate line 104 is greater than the distance between the second gate line 104 and the adjacent first gate line 103. This arrangement can avoid the problem of short circuit between the connection structure 107 and the second gate line 104 due to the distance between the connection structure 107 and the functional portion 116 of the adjacent second gate line 104 being too small.

[0076] In some embodiments, along the first direction X, the distance between the connection structure 107 and the functional portion 116 of the adjacent second gate line 104 is 0.5 mm to 1.2 mm, for example, 0.5 mm, 0.7 mm, 0.9 mm, 1 mm or 1.2 mm.

[0077] In some embodiments, along the second direction Y, the length of the first connecting portion 123 is 0.5mm to 2mm, for example, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm, the length of the first main body 113 is 0.5mm to 2mm, for example, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm, the length of the second connecting portion 124 is 0.5mm to 2mm, for example, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm, and the length of the second main body 114 is 0.5mm to 2mm, for example, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm or 2mm. The lengths of the first connecting portion 123, the first main portion 113, the second connecting portion 124, and the second main portion 114 are within the above range, which can ensure the rate at which the first gate line 103 and the second gate line 104 collect carriers while reducing the metal recombination between the first gate line 103 and the first doped conductive layer 101 due to the excessive contact area, and reduce the metal recombination between the second gate line 104 and the second doped conductive layer 102 due to the excessive contact area.

[0078] The second connection line 106 adjacent to the edge connection line 115 includes a functional portion 116 and a spacer 126 . The functional portion 116 is connected to the second gate line 104 . The spacer 126 is used to separate adjacent functional portions 116 and provide a connection space for the connection structure 107 to connect the edge connection line 115 and the adjacent middle connection line 125 .

[0079] In some embodiments, the functional part 116 is connected to 6 to 10 first gate lines 103. For example, the functional part 116 is connected to 6, 7, 8, 9 or 10 first gate lines 103. In this way, the number of first gate lines 103 connected to the functional part 116 is moderate, which can avoid the functional part 116 being connected to too many first gate lines 103, which may cause the dense connection points between the functional part 116 and the first gate lines 103 to weaken the mechanical strength of the back contact battery, and can also avoid the functional part 116 being connected to too few first gate lines 103, resulting in the functional part 116 having a weaker performance in collecting carriers.

[0080] Figure 5 A third structural schematic diagram of a back contact battery provided in an embodiment of the present disclosure, Figure 6 for Figure 5 A partial enlarged schematic diagram of part B.

[0081] Combined with reference Figure 1 , Figure 5 and Figure 6 In some embodiments, the functional portion 116 includes a first portion 1161 adjacent to the connection structure 107, and a second portion 1162 connected to the first portion 1161; along the second direction Y, the width of the first portion 1161 is greater than the width of the second portion 1162. The larger width of the first portion 1161 can increase the contact area between the second connection line 106 and the welding strip, increase the welding tension between the welding strip and the back contact cell, and thus avoid the occurrence of cold welding or poor welding quality between the back contact cell and the welding strip, thereby improving the yield of the photovoltaic module.

[0082] In some embodiments, along the second direction Y, the width of the first portion 1161 is 0.02 mm to 0.1 mm, such as 0.02 mm, 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.08 mm or 1 mm, and the width of the second portion 1162 is 0.01 mm to 0.05 mm, such as 0.01 mm, 0.02 mm, 0.03 mm, 0.04 mm or 0.05 mm. When the width of the first portion 1161 and the width of the second portion 1162 are within the above range, the welding quality with the welding strip can be ensured, and the manufacturing cost of the first portion 1161 and the second portion 1162 can be avoided because the width of the first portion 1161 and the second portion 1162 is set too wide, which wastes the manufacturing cost of the first portion 1161 and the second portion 1162.

[0083] Figure 7 A fourth structural schematic diagram of a back contact battery provided in an embodiment of the present disclosure, Figure 8 for Figure 7 A partial enlarged schematic diagram of part C in the middle.

[0084] Combined with reference Figure 1 , Figure 7 and Figure 8 In some embodiments, the first connection portion 123 is electrically connected to the first connection line 105, and the second connection portion 124 is electrically connected to the second connection line 106. In the first direction X, the width of the first connection portion 123 is greater than the width of the first main body portion 113, and the width of the second connection portion 124 is greater than the width of the second main body portion 114.

[0085] The first connection portion 123 is electrically connected to the first connection line 105. The width of the first connection portion 123 is set relatively large, which can increase the contact area between the first connection portion 123 and the first connection line 105, thereby increasing the rate at which the first connection line 105 collects carriers on the first grid line 103, and further improving the performance of the back contact battery. In addition, the width of the first connection portion 123 is set relatively large, and it is also possible to not set a pad, but use the first connection portion 123 with a relatively large width as the contact portion between the back contact battery and the welding strip to complete the electrical connection between the back contact battery and the welding strip, thereby saving the material usage of the pad, and reducing the process steps for forming the pad, thereby saving the preparation cost of the photovoltaic module and improving the preparation efficiency of the photovoltaic module.

[0086] Similarly, the first connection portion 123 is electrically connected to the second connection line 106, and the width of the second connection portion 124 is set relatively large, which can increase the contact area between the second connection portion 124 and the second connection line 106, thereby increasing the rate at which the second connection line 106 collects carriers on the second grid line 104, and further improving the performance of the back contact battery. In addition, if the width of the second connection portion 124 is set relatively large, it is also possible to not set a pad, but use the second connection portion 124 with a relatively large width as the connecting portion between the back contact battery and the welding strip to complete the electrical connection between the back contact battery and the welding strip, thereby saving the material usage of the pad, and reducing the process steps for forming the pad, thereby saving the preparation cost of the photovoltaic module and improving the preparation efficiency of the photovoltaic module.

[0087] In some embodiments, along the first direction X, the width of the first connecting portion 123 is 0.02mm~0.1mm, for example 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm or 1mm, the width of the first main body portion 113 is 0.01mm~0.05mm, for example 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm, the width of the second connecting portion 124 is 0.02mm~0.1mm, for example 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm or 1mm, and the width of the second main body portion 114 is 0.01mm~0.05mm, for example 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm. The width of the first connecting portion 123, the width of the first main portion 113, the width of the second connecting portion 124, and the width of the second main portion 114 are within the above ranges, which can increase the rate at which the first connecting line 105 collects carriers on the first gate line 103, and can also avoid waste of resources due to the widths of the first connecting portion 123, the first main portion 113, the second connecting portion 124, and the second main portion 114 being set too wide.

[0088] Fig. 9 A fifth structural schematic diagram of a back-contact battery provided in an embodiment of the present disclosure.

[0089] It should be noted that, for example, Fig. 9 The shapes of the first pad 108 and the second pad 109 are rectangular. In fact, the shape of the first pad can also be triangular, circular, polygonal, I-shaped or other shapes, and the shape of the second pad can also be triangular, circular, polygonal, I-shaped or other shapes.

[0090] In some embodiments, the back contact cell further includes: a first pad 108, the first pad 108 is located at the junction of a portion of the first connection line 105 and the first grid line 103, and is electrically connected to the first connection line 105 and the first grid line 103; a second pad 109, the second pad 109 is located at the junction of a portion of the second connection line 106 and the second grid line 104, and is electrically connected to the second connection line 106 and the second grid line 104; the second surface 120 further includes a third edge 150 connected to the first edge 130, along the first direction X, the first pad 108 adjacent to the third edge 150 is spaced from the first grid line 103 adjacent to the third edge 150, and the second pad 109 adjacent to the third edge 150 is spaced from the first grid line 103 adjacent to the third edge 150. That is, no pad is provided on the first grid line 103 and the second grid line 104 adjacent to the third edge 150, so that the problem of the back contact cell being broken or cracked due to welding stress near the third edge 150 can be avoided, thereby improving the yield of the photovoltaic module.

[0091] In some embodiments, the distance d3 between the first pad 108 adjacent to the third edge 150 and the first grid line 103 adjacent to the third edge 150 is 5 mm to 15 mm, for example, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm or 15 mm, and the distance d4 between the second pad 109 adjacent to the third edge 150 and the first grid line 103 adjacent to the third edge 150 is 5 mm to 15 mm, for example, 5 mm, 7 mm, 9 mm, 11 mm, 13 mm or 15 mm. When the distance is within the above range, the problem of cracking or hidden cracking of the back contact battery due to welding stress near the third edge 150 can be avoided, and the first pad 108 and the second pad 109 can also ensure that sufficient connection force is provided for connecting the back contact battery and the welding ribbon.

[0092] In some embodiments, the area of ​​the first pad 108 close to the third edge 150 is larger than the area of ​​the first pad 108 far from the third edge 150; and along the thickness direction of the substrate 100, the area of ​​the second pad 109 close to the third edge 150 is larger than the area of ​​the second pad 109 far from the third edge 150. In this way, the contact area between the first pad 108, the second pad 109 and the soldering ribbon can be increased to ensure the welding quality between the back contact battery and the soldering ribbon.

[0093] Among them, the thickness direction of the substrate 100 refers to the direction from the first surface 110 to the second surface 120, the area of ​​the first pad 108 is the contact area between the first pad 108 and the passivation layer on the substrate 100, and the area of ​​the second pad 109 is the contact area between the second pad 109 and the passivation layer on the substrate 100.

[0094] In the above-mentioned back-contact battery, one end of the connection structure 107 is electrically connected to the edge connection line 115, and the other end is electrically connected to the middle connection line 125 adjacent to the edge connection line 115 through the spacer 126. The middle connection line 125 adjacent to the edge connection collects the current collected by the edge connection line 115 through the connection structure 107, so that no welding part is provided on the edge connection line 115, thereby avoiding the problem of rupture or hidden cracks at the edge of the back contact battery due to welding stress, thereby improving the yield of the photovoltaic module.

[0095] On the one hand, the first gate line 103 electrically connected to the middle connection line 125 includes two first main body parts 113 arranged at intervals and a first connection part 123 connecting the two first main bodies, and the first connection part 123 is not in electrical contact with the first doped conductive layer 101, so that the contact area between the first gate line 103 and the first doped conductive layer 101 is small, thereby reducing the metal recombination between the first gate line 103 and the first doped conductive layer 101. On the other hand, the second gate line 104 includes two second main body parts 114 arranged at intervals and a second connection part 124 connecting the two second main body parts 114, and the second connection part 124 is not in electrical contact with the second doped conductive layer 102, so that the contact area between the second gate line 104 and the second doped conductive layer 102 is small, thereby reducing the metal recombination between the second gate line 104 and the second doped conductive layer 102, and the above two aspects are conducive to improving the performance of the back contact battery.

[0096] The disclosed embodiment also provides a photovoltaic module, which includes a plurality of back-contact cells provided in any of the above embodiments, and is used to convert received light energy into electrical energy. It should be noted that the parts that are the same or corresponding to the above embodiments can refer to the corresponding description of the above embodiments, and will not be repeated below.

[0097] Fig.10 A schematic diagram of a cross-sectional structure of a photovoltaic module provided in an embodiment of the present disclosure.

[0098] refer to Fig.10 The photovoltaic module includes: a battery string, which is formed by connecting the back contact batteries 10 described in any of the above embodiments; a welding strip 11, which is used to connect adjacent back contact batteries 10; a packaging film 12, which is used to cover the surface of the battery string; and a cover plate 13, which is used to cover the surface of the packaging film away from the battery string.

[0099] In some embodiments, the back contact cell 10 can also be an IBC (Interdigitated Back Contact), an HPBC (Hybrid Passivated Back Contact), a TBC cell that superimposes TOPCon technology and IBC technology, or an HBC cell that superimposes HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back contact cells.

[0100] In some embodiments, the back contact cell 10 may be a whole cell or a sliced ​​cell, wherein a sliced ​​cell refers to a cell formed by a complete whole cell through a cutting process. The back contact cell 10 is electrically connected in the form of a whole cell or multiple slices to form a plurality of cell strings, and the plurality of cell strings are electrically connected in series and / or in parallel.

[0101] The soldering ribbon 11 is used to connect adjacent back-contact cells 10 and transmit the current collected on the back-contact cells 10 connected to the soldering ribbon 11 to the component end connected to the cell string. One end of the soldering ribbon 11 is electrically connected to the first busbar of a back-contact cell 10, and the other end of the soldering ribbon 11 is electrically connected to the second busbar of the adjacent back-contact cell 10.

[0102] In some embodiments, the encapsulation film 12 includes a first encapsulation layer and a second encapsulation layer, wherein the first encapsulation layer covers one of the front side or the back side of the back contact battery 10, and the second encapsulation layer covers the other of the front side or the back side of the back contact battery 10. Specifically, at least one of the first encapsulation layer or 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 co-elastomer (POE) film, or a polyethylene terephthalate (PET) film, or at least one of the first encapsulation layer or the second encapsulation layer may also be an EP film, an EPE film, or a PVP film.

[0103] Among them, EP film refers to a co-extruded film composed of stacked EVA film and POE film, EPE film refers to a co-extruded film formed by stacking EVA film + POE film + EVA film in sequence, and PVP film refers to a co-extruded film formed by stacking POE film + EVA film + POE film. The co-extruded film can be manufactured by sequentially extruding one or more raw materials onto another already manufactured film during the film processing process, or bonding different types of already manufactured films together.

[0104] In some cases, there is a boundary line between the first encapsulation layer and the second encapsulation layer before lamination. After the lamination process, the photovoltaic module is formed and there is no longer the concept of the first encapsulation layer and the second encapsulation layer, that is, the first encapsulation layer and the second encapsulation layer have formed an integral encapsulation film.

[0105] In some embodiments, the cover plate 13 may be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. Specifically, the surface of the cover plate facing the encapsulation film may be a concave-convex surface or a velvet surface including a plurality of convex structures, thereby increasing the utilization rate of the incident light. The cover plate 13 includes a first cover plate and a second cover plate, the first cover plate is opposite to the first encapsulation layer, and the second cover plate is opposite to the second encapsulation layer.

[0106] Those skilled in the art can understand that the above-mentioned embodiments are specific examples for realizing the present disclosure, and in practical applications, various changes can be made to them 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, so the protection scope of the present disclosure shall be based on the scope defined in the claims.

Claims

1. A back contact battery, characterized in that: include: a substrate having opposing first and second sides, the second side having a first edge; a first doped conductive layer and a second doped conductive layer, wherein the first doped conductive layer and the second doped conductive layer are alternately distributed on the second surface, and the doping element in the first doped conductive layer and the doping element in the second doped conductive layer have different conductivity types; First gate lines and second gate lines are alternately arranged along a first direction, at least a portion of the first gate lines are in electrical contact with the first doped conductive layer, and at least a portion of the second gate lines are in electrical contact with the second doped conductive layer; First connection lines and second connection lines are alternately arranged along a second direction, the first connection lines are electrically connected to the first gate lines, the first connection lines include edge connection lines and middle connection lines, no welding portion is provided on the edge connection lines, the second connection lines adjacent to the edge connection lines include a functional portion and a spacing portion, the functional portion is connected to the second gate lines; A connection structure, one end of which is electrically connected to the edge connection line, and the other end of which passes through the spacer and is electrically connected to the middle connection line adjacent to the edge connection line; Among them, the first gate line electrically connected to the intermediate connecting line includes two first main parts arranged at intervals and a first connecting part connecting the two first main parts, and the first connecting part is not electrically in contact with the first doped conductive layer; the second gate line includes two second main parts arranged at intervals and a second connecting part connecting the two second main parts, and the second connecting part is not electrically in contact with the second doped conductive layer.

2. The back contact cell according to claim 1, characterized in that: The functional portion includes a first portion adjacent to the connection structure, and a second portion connected to the first portion; along the second direction, a width of the first portion is greater than a width of the second portion.

3. The back contact battery according to claim 2, characterized in that: Along the second direction, the width of the first portion is 0.02 mm to 0.1 mm, and the width of the second portion is 0.01 mm to 0.05 mm.

4. The back contact cell according to claim 1, characterized in that: The first connection portion is electrically connected to the first connection line, and the second connection portion is electrically connected to the second connection line. In the first direction, the width of the first connection portion is greater than the width of the first main body portion, and the width of the second connection portion is greater than the width of the second main body portion.

5. The back contact cell according to claim 4, characterized in that: Along the first direction, the width of the first connecting portion is 0.02 mm to 0.1 mm, the width of the first main body portion is 0.01 mm to 0.05 mm, the width of the second connecting portion is 0.02 mm to 0.1 mm, and the width of the second main body portion is 0.01 mm to 0.05 mm.

6. The back contact cell according to claim 1, characterized in that: Along the second direction, the distance between the edge connection line and the adjacent second connection line is a first spacing, the distance between the second connection line adjacent to the edge connection line and the adjacent middle connection line is a second spacing, and the first spacing is smaller than the second spacing.

7. The back contact cell according to claim 6, characterized in that: The first spacing is 0.5 mm to 1.5 mm, and the second spacing is 0.7 mm to 2.0 mm.

8. The back contact cell according to claim 1, characterized in that: The back contact battery further comprises: A first pad, the first pad is located at a junction of a portion of the first connecting line and the first gate line, and is electrically connected to the first connecting line and the first gate line; A second pad, the second pad is located at a junction of a portion of the second connecting line and the second gate line, and is electrically connected to the second connecting line and the second gate line; The second surface also includes a third edge connected to the first edge. Along the first direction, the first pad adjacent to the third edge is spaced apart from the first gate line adjacent to the third edge, and the second pad adjacent to the third edge is spaced apart from the first gate line adjacent to the third edge.

9. The back contact battery according to claim 8, characterized in that Along the first direction, the distance between the first pad adjacent to the third edge and the first gate line adjacent to the third edge is 5 mm to 15 mm, and the distance between the second pad adjacent to the third edge and the first gate line adjacent to the third edge is 5 mm to 15 mm.

10. A photovoltaic module, characterized in that: include: A battery string, formed by connecting a plurality of back-contact batteries as claimed in any one of claims 1 to 9; A soldering ribbon, the soldering ribbon is used to connect adjacent back contact cells; A packaging film, used to cover the surface of the battery string; The cover plate is used to cover the surface of the packaging film away from the battery string.

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