Back contact battery and photovoltaic module

Abstract

The embodiment of the utility model 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] This disclosure relates to the photovoltaic field, and particularly to a back-contact battery and a photovoltaic module. Background Technology

[0002] Currently, with the gradual depletion of fossil fuels, solar cells are becoming increasingly widely used as a new energy alternative. A solar cell is a device that converts sunlight into electrical energy. Solar cells utilize the photovoltaic principle to generate charge carriers, which are then extracted using electrodes, thus facilitating the efficient utilization of electrical energy.

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

[0004] However, the edges of the back-contact cells in the relevant technologies are at risk of cracking, resulting in a low yield of photovoltaic modules. Utility Model Content

[0005] This disclosure provides a back-contact battery and a photovoltaic module, which at least improve the performance of the back-contact battery and the yield of the photovoltaic module.

[0006] According to some embodiments of this disclosure, one aspect of this disclosure provides a back-contact battery, comprising: a substrate having opposing first and second surfaces, the second surface having a first edge; a first doped conductive layer and a second doped conductive layer, the first and second doped conductive layers being alternately distributed on the second surface, wherein the doping elements in the first and second doped conductive layers have different conductivity types; a first grid line and a second grid line alternately arranged along a first direction, at least a portion of the first grid line being in electrical contact with the first doped conductive layer, and at least a portion of the second grid line being in electrical contact with the second doped conductive layer; and a first connecting line and a second connecting line alternately arranged along a second direction, the first connecting line being electrically connected to the first grid line. The system includes an edge connection line and a middle connection line. The edge connection line does not have a soldering 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 is provided, with one end electrically connected to the edge connection line and the other end passing through the spacing portion and electrically connected to the middle connection line adjacent to the edge connection line. The first gate line electrically connected to the middle connection line includes two spaced-apart first main body portions and a first connection portion connecting the two first main body portions. The first connection portion does not make electrical contact with the first doped conductive layer. The second gate line includes two spaced-apart second main body portions and a second connection portion connecting the two second main body portions. The second connection portion does not make electrical contact with the second doped conductive layer.

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

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

[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 to 0.1mm, the width of the first main body portion is 0.01mm to 0.05mm, the width of the second connecting portion is 0.02mm to 0.1mm, and the width of the second main body portion is 0.01mm to 0.05mm.

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

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

[0013] In some embodiments, the back contact battery further includes: a first pad located at the intersection of a portion of the first connection line and the first gate line, and electrically connected to the first connection line and the first gate line; a second pad located at the intersection of a portion of the second connection line and the second gate line, and electrically connected to the second connection line and the second gate line; the second surface further includes a third edge connected to the first edge, wherein, 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.

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

[0015] According to some embodiments of this disclosure, another aspect of this disclosure also provides a photovoltaic module, including a battery string formed by connecting a plurality of back-contact batteries as described in any of the above embodiments; a solder ribbon for connecting adjacent back-contact batteries; an encapsulating film for covering the surface of the battery string; and a cover plate for covering the surface of the encapsulating film facing away from the battery string.

[0016] The technical solutions provided in this disclosure have at least the following advantages:

[0017] In the aforementioned 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 intermediate connection line adjacent to the edge connection line through a spacer. The connection structure allows the intermediate connection line adjacent to the edge connection line to collect the current gathered by the edge connection line, so that no welding part is required on the edge connection line. This avoids the problem of cracking or microcracks at the edge of the back-contact battery due to welding stress, thereby improving the yield of photovoltaic modules.

[0018] Furthermore, the first grid line electrically connected to the intermediate connecting line includes two spaced-apart first main bodies and a first connecting portion connecting the two first main bodies. The first connecting portion does not make electrical contact with the first doped conductive layer, resulting in a smaller contact area between the first grid line and the first doped conductive layer. This reduces metal recombination between the first grid line and the first doped conductive layer, thereby improving the performance of the back contact battery. Similarly, the second grid line includes two spaced-apart second main bodies and a second connecting portion connecting the two second main bodies. The second connecting portion does not make electrical contact with the second doped conductive layer, resulting in a smaller contact area between the second grid line and the second doped conductive layer. This reduces metal recombination between the second grid line and the second doped conductive layer, thereby improving the performance of the back contact battery. Attached Figure Description

[0019] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

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

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

[0022] Figure 3 for Figure 2 A magnified view of part A in the middle;

[0023] Figure 4 A schematic diagram of a second structure of a back contact battery provided for an embodiment of this disclosure;

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

[0025] Figure 6 for Figure 5 A magnified view of part B in the middle section;

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

[0027] Figure 8 for Figure 7 A magnified view of part C in the middle;

[0028] Figure 9 A schematic diagram of a fifth structure of a back contact battery provided in an embodiment of this disclosure;

[0029] Figure 10 This is a cross-sectional view of a photovoltaic module provided in an embodiment of this disclosure. Detailed Implementation

[0030] In the back-contact cells of related technologies, pads and solder ribbons are set on the grid lines at the edge of the cells. The solder ribbons electrically connect multiple back-contact cells to form a cell string in the photovoltaic module. However, during the process of welding the pads and solder ribbons on the grid lines at the edge, the back-contact cells are prone to cracking due to the high stress concentration at the edge of the back-contact cells, resulting in a low yield of the photovoltaic module.

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

[0032] In the back contact battery provided in this embodiment, one end of the connection structure is electrically connected to the edge connection line, and the other end is electrically connected to the intermediate connection line adjacent to the edge connection line through a spacer. The connection structure enables the intermediate connection line adjacent to the edge connection line to collect the current collected by the edge connection line, so that no welding part (such as solder joint or solder pad) is required on the edge connection line. This avoids the problem of cracking or microcracks at the edge of the back contact battery due to welding stress, thereby improving the yield of photovoltaic modules.

[0033] On one hand, the first grid line electrically connected to the intermediate connecting line includes two spaced-apart first main bodies and a first connecting part connecting the two first main bodies. The first connecting part does not make electrical contact with the first doped conductive layer, resulting in a smaller contact area between the first grid line and the first doped conductive layer, thereby reducing metal recombination between the first grid line and the first doped conductive layer. On the other hand, the second grid line includes two spaced-apart second main bodies and a second connecting part connecting the two second main bodies. The second connecting part does not make electrical contact with the second doped conductive layer, resulting in a smaller contact area between the second grid line and the second doped conductive layer, thereby reducing metal recombination between the second grid line and the second doped conductive layer. Both of these aspects are beneficial to improving the performance of the back contact battery.

[0034] In the description of the embodiments of this disclosure, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this disclosure, "a plurality of" means two or more, unless otherwise explicitly defined.

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

[0036] In the description of the embodiments of this disclosure, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent three cases: A exists, A and B exist simultaneously, and B exists. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0037] In the description of the embodiments of this disclosure, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0038] In the description of the embodiments of this disclosure, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this disclosure.

[0039] In the description of the embodiments of this disclosure, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0040] In the accompanying drawings corresponding to the embodiments of this disclosure, the thickness and area of ​​the layers are enlarged for better understanding and ease of description. When describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component may be "directly" located on the surface of the other component, or there may be a third component between the two components. Conversely, when describing a component on the surface of another component, or when another component is formed or disposed on the surface of a component, it indicates that there is no third component between the two components. Furthermore, when describing a component as being "generally" formed on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor is it formed on a portion of the edge of the entire surface.

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

[0042] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.

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

[0044] Reference Figures 1 to 3The back contact battery includes: a 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 doping elements in the first doped conductive layer 101 and the doping elements in the second doped conductive layer 102 having different conductivity types; a first grid line 103 and a second grid line 104 alternately arranged along a first direction X, at least a portion of the first grid line 103 being in electrical contact with the first doped conductive layer 101, and at least a portion of the second grid line 104 being in electrical contact with the second doped conductive layer 102; a first connecting line 105 and a second connecting line 106 alternately arranged along a second direction Y, the first connecting line 105 being electrically connected to the first grid line 103, the first connecting line 105 including an edge connecting line 115 and a middle connecting line 130. Intermediate connecting line 125 and edge connecting line 115 are not provided with welding parts. The second connecting line 106 adjacent to the edge connecting line 115 includes a functional part 116 and a spacer part 126. The functional part 116 is connected to the second gate line 104. The connecting structure 107 is electrically connected to the edge connecting line 115 at one end and passes through the spacer part 126 to be electrically connected to the intermediate connecting line 125 adjacent to the edge connecting line 115 at the other end. The first gate line 103 electrically connected to the intermediate connecting line 125 includes two first main body parts 113 spaced apart and a first connecting part 123 connecting the two first main body parts 113. The first connecting part 123 is not in electrical contact with the first doped conductive layer 101. The second gate line 104 includes two second main body parts 114 spaced apart and a second connecting part 124 connecting the two second main body parts 114. The second connecting part 124 is not in electrical contact with the second doped conductive layer 102.

[0045] Back-contact batteries are used to absorb sunlight and convert light energy 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 monocrystalline, polycrystalline, amorphous, or microcrystalline (a state simultaneously possessing both monocrystalline and amorphous states is called microcrystalline). For example, silicon may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon.

[0048] In some embodiments, the substrate 100 may also be a compound semiconductor material. Common compound semiconductor materials include, but are not limited to, silicon germanide, silicon carbide, gallium arsenide, indium gallium arsenide, perovskite, cadmium telluride, copper indium selenide, etc.

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

[0050] 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 dopant element, which can be any one of group V elements such as phosphorus (P), bismuth (Bi), antimony (Sb), or arsenic (As). The P-type semiconductor substrate is doped with a P-type dopant element, which can be any one of group III 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 opposite to each other.

[0052] In some embodiments, the back-contact battery is a single-sided battery, in which case the first surface 110 of the substrate 100 can serve as a light-receiving surface to receive incident light, and the second surface 120 serves as a back-lighting surface. In some embodiments, the back-contact battery is a double-sided battery, in which case both the first surface 110 and the second surface 120 of the substrate 100 can serve as light-receiving surfaces and can both be used to receive incident light. It is understood that the back-lighting surface referred to in the embodiments of this application can also receive incident light, but the degree of reception of incident light is weaker than that of the light-receiving surface, and therefore it is defined as a back-lighting surface.

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

[0054] In some embodiments, the textured surface can be a pyramid textured surface. As a common textured surface, pyramid textured surface not only reduces the reflectivity of the substrate surface, but also forms a light trap, 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 battery is a single-sided battery, a textured surface can be formed on the light-receiving surface of the substrate, such as a pyramidal textured surface, while the back-lighting surface of the substrate can be a polished surface, meaning the back-lighting surface of the substrate is flatter than the light-receiving surface. It should be noted that for single-sided batteries, a textured surface can also be formed on both the light-receiving and back-lighting surfaces of the substrate.

[0056] If the back-contact battery is a bi-sided battery, a textured surface can be formed on both the light-receiving and back-light-receiving surfaces of the substrate.

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

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

[0059] The first doped conductive layer 101 and the second doped conductive layer 102 may have a gap or isolation structure to achieve automatic isolation between regions with different conductivity types. This can prevent 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, which would cause leakage and affect battery efficiency.

[0060] At least a portion of the first gate line 103 is in electrical contact with the first doped conductive layer 101, and at least a portion 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 the current of the back contact battery.

[0061] The first connecting 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 connecting 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 connecting line 105 is not in electrical contact with the first doped conductive layer 101, and the second connecting 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. In this way, the connection structure 107 can not only enable the current to pass through the edge connection line 115 and the adjacent intermediate connection line 125, but also collect the current on the surface of the substrate 100 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 metal recombination problems caused by the connection structure 107 being in electrical contact with the first doped conductive layer 101, which can improve the performance of the back contact battery.

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

[0067] In the first gate line 103, the first main body portion 113 is in electrical contact with the first doped conductive layer 101. This contact can occur if the first main body portion 113 penetrates the passivation layer. The first connecting portion 123 is not in electrical contact with the first doped conductive layer 101. This can occur if at most a portion of the first connecting portion 123 is embedded within the passivation layer without penetrating it, thus avoiding electrical contact with the first doped conductive layer 101. Similarly, the first connecting line 105 is not in electrical contact with the first doped conductive layer 101. This can occur if at most a portion of the first connecting line 105 is embedded within the passivation layer without penetrating it, thus avoiding electrical contact with the first doped conductive layer 101.

[0068] The second main body portion 114 of the second gate line 104 is electrically contacted with the second doped conductive layer 102. This contact can occur if the second main body portion 114 penetrates the passivation layer. The second connecting portion 124 is not electrically contacted with the second doped conductive layer 102. This can occur if at most a portion of the second connecting portion 124 is embedded within the passivation layer without penetrating it, thus avoiding electrical contact with the second doped conductive layer 102. Similarly, the second connecting line 106 is not electrically contacted with the second doped conductive layer 102. This can also occur if at most a portion of the second connecting line 106 is embedded within the passivation layer without penetrating it, thus avoiding electrical contact with the second doped conductive layer 102.

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

[0070] Figure 4 A schematic diagram of a second structure of a back contact battery provided for an embodiment of this disclosure.

[0071] In other embodiments, if the sum of the first connecting line 105 and the second connecting line 106 is an even number, refer to Figure 1 and Figure 4 Then the second surface 120 has a second edge 140 disposed opposite to the first edge 130. The conductivity type of the second edge connecting line 136, the conductivity type of the second connecting structure 117, and the conductivity type of the second connecting line 106 corresponding to the second edge 140 are all the same. Then the first connecting line 105 disposed adjacent to the second edge connecting line 136 should also be designed in the same way as the second connecting line 106 described above, that is, the second edge connecting line 136 near the second edge 140 passes through the break of the first connecting line 105 and connects to the adjacent second connecting line 106.

[0072] Continue to refer to Figures 1 to 3 In some embodiments, along the second direction Y, the distance between the edge connecting line 115 and the adjacent second connecting line 106 is a first spacing d1, and the distance between the second connecting line 106 adjacent to the edge connecting line 115 and the adjacent intermediate connecting line 125 is a second spacing d2. The first spacing d1 is smaller than the second spacing d2. The smaller first spacing d1 allows for a smaller length of the connection structure 107 connecting the edge connecting line 115 and the adjacent intermediate connecting line 125. This reduces the path length for the intermediate connecting line 125 adjacent to the edge connecting line 115 to collect carriers on the edge connecting line 115, thereby improving the collection efficiency of the intermediate connecting line 125 adjacent to the edge connecting line 115 and thus enhancing the performance of the back contact battery.

[0073] In some embodiments, the first spacing d1 is 0.5mm to 1.5mm, for example, 0.5mm, 0.7mm, 0.9mm, 1mm, 1.2mm, or 1.5mm, and the second spacing d2 is 0.7mm to 2.0mm, for example, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm, or 2mm. When the first spacing d1 and the second spacing d2 are within the above ranges, the collection efficiency of the intermediate connecting line 125 adjacent to the edge connecting line 115 is ensured, while also preventing short circuits between the first connecting line 105 and the second connecting line 106 due to excessively small first and second spacings.

[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 intermediate connection line 125. The edge connection line 115 collects the charge carriers of multiple first gate lines 103 and transmits them through the connection structure 107 to the intermediate connection line 125 adjacent to the edge connection line 115. Therefore, the width of the connection structure 107 needs to be set relatively large in order to complete the transmission of the charge carriers collected by the edge connection line 115 to the intermediate connection line 125 adjacent to the edge connection line 115.

[0075] In some embodiments, along the first direction X, the distance between the connecting 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 prevent short circuits between the connecting structure 107 and the second gate line 104 caused by the distance between the connecting 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 connecting structure 107 and the functional portion 116 of the adjacent second gate line 104 is 0.5mm to 1.2mm, for example 0.5mm, 0.7mm, 0.9mm, 1mm or 1.2mm.

[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 portion 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 portion 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 body portion 113, the second connecting portion 124, and the second main body portion 114 are within the above-mentioned range. This ensures the rate at which the first gate line 103 and the second gate line 104 collect charge carriers, while reducing metal recombination between the first gate line 103 and the first doped conductive layer 101 due to excessive contact area, and also reduces metal recombination between the second gate line 104 and the second doped conductive layer 102 due to excessive contact area.

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

[0079] In some embodiments, the functional unit 116 connects to 6 to 10 first gate lines 103. For example, the functional unit 116 connects 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 unit 116 is moderate, which can avoid the functional unit 116 connecting to too many first gate lines 103, which could weaken the mechanical strength of the back contact battery due to dense connection points between the functional unit 116 and the first gate lines 103. It can also avoid the functional unit 116 connecting to too few first gate lines 103, which would result in a weaker carrier collection performance.

[0080] Figure 5 This is a schematic diagram of a third structure of a back-contact battery provided in an embodiment of this disclosure. Figure 6 for Figure 5 A magnified view of part B in the diagram.

[0081] Reference Figure 1 , Figure 5 and Figure 6 In some embodiments, the functional part 116 includes a first part 1161 adjacent to the connecting structure 107 and a second part 1162 connected to the first part 1161; along the second direction Y, the width of the first part 1161 is greater than the width of the second part 1162. The larger width of the first part 1161 can increase the contact area between the second connecting line 106 and the solder strip, improve the welding pull between the solder strip and the back contact cell, and thus avoid the problem of incomplete soldering or poor welding quality between the back contact cell and the solder strip, thereby improving the yield of photovoltaic modules.

[0082] In some embodiments, along the second direction Y, the width of the first portion 1161 is 0.02mm to 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 portion 1162 is 0.01mm to 0.05mm, for example, 0.01mm, 0.02mm, 0.03mm, 0.04mm, or 0.05mm. The widths of the first portion 1161 and the second portion 1162 being within the above ranges ensure welding quality with the solder strip while avoiding wasting manufacturing costs due to excessively wide widths of the first portion 1161 and the second portion 1162.

[0083] Figure 7 This is a schematic diagram of a fourth structure of a back-contact battery provided in an embodiment of this disclosure. Figure 8 for Figure 7 A magnified view of part C in the middle.

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

[0085] The first connecting portion 123 is electrically connected to the first connecting line 105. The larger width of the first connecting portion 123 increases the contact area between it and the first connecting line 105, thereby increasing the rate at which the first connecting line 105 collects charge carriers from the first grid line 103, and ultimately improving the performance of the back contact cell. Furthermore, the larger width of the first connecting portion 123 eliminates the need for solder pads; instead, the wider portion serves as the contact area between the back contact cell and the solder strip, completing the electrical connection. This saves on solder pad material usage and reduces the number of steps required to form the solder pads, thus reducing the manufacturing cost of the photovoltaic module and improving its manufacturing efficiency.

[0086] Similarly, the first connecting portion 123 is electrically connected to the second connecting line 106. The second connecting portion 124 has a larger width, which increases the contact area between the second connecting portion 124 and the second connecting line 106, thereby increasing the rate at which the second connecting line 106 collects charge carriers on the second grid line 104, and thus improving the performance of the back contact cell. In addition, the larger width of the second connecting portion 124 also eliminates the need for solder pads. Instead, the wider second connecting portion 124 serves as the connection between the back contact cell and the solder strip, completing the electrical connection between the back contact cell and the solder strip. This saves on the material usage of solder pads and reduces the number of process steps in forming solder pads, thereby reducing the manufacturing cost of photovoltaic modules and improving the manufacturing efficiency of photovoltaic modules.

[0087] In some embodiments, along the first direction X, the width of the first connecting portion 123 is 0.02mm to 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 to 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 to 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 to 0.05mm, for example 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm. The widths of the first connecting portion 123, the first main body portion 113, the second connecting portion 124, and the second main body portion 114 are within the aforementioned range. This can improve the rate at which the first connecting line 105 collects carriers on the first gate line 103, and also avoid resource waste caused by setting the widths of the first connecting portion 123, the first main body portion 113, the second connecting portion 124, and the second main body portion 114 to be too wide.

[0088] Figure 9 This is a schematic diagram of a fifth structure of a back contact battery provided in an embodiment of this disclosure.

[0089] It should be noted that this is an example. Figure 9 The first pad 108 and the second pad 109 are rectangular in shape. In fact, the shape of the first pad can also be a triangle, a circle, a polygon, an I-shape or other shapes, and the shape of the second pad can also be a triangle, a circle, a polygon, an I-shape or other shapes.

[0090] In some embodiments, the back contact cell further includes: a first pad 108, located at the junction of a portion of the first connection line 105 and the first gate line 103, and electrically connected to the first connection line 105 and the first gate line 103; a second pad 109, located at the junction of a portion of the second connection line 106 and the second gate line 104, and electrically connected to the second connection line 106 and the second gate 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 apart from the first gate line 103 adjacent to the third edge 150, and the second pad 109 adjacent to the third edge 150 is spaced apart from the first gate line 103 adjacent to the third edge 150. That is, no pads are provided on the first gate line 103 and the second gate line 104 near the third edge 150, thereby avoiding the problem of cracking or microcracks of the back contact cell near the third edge 150 due to welding stress, and thus 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 gate line 103 adjacent to the third edge 150 is 5mm to 15mm, for example, 5mm, 7mm, 9mm, 11mm, 13mm, or 15mm; and the distance d4 between the second pad 109 adjacent to the third edge 150 and the first gate line 103 adjacent to the third edge 150 is 5mm to 15mm, for example, 5mm, 7mm, 9mm, 11mm, 13mm, or 15mm. Distances within the above range can prevent the back contact battery from cracking or developing microcracks near the third edge 150 due to welding stress, and can also ensure that the first pad 108 and the second pad 109 provide sufficient connection force for connecting the back contact battery and the solder strip.

[0092] In some embodiments, the area of ​​the first pad 108 near the third edge 150 is larger than the area of ​​the first pad 108 away from the third edge 150; and along the thickness direction of the substrate 100, the area of ​​the second pad 109 near the third edge 150 is larger than the area of ​​the second pad 109 away from the third edge 150. This configuration can increase the contact area between the first pad 108, the second pad 109 and the solder strip, thereby ensuring the welding quality between the back contact battery and the solder strip.

[0093] Wherein, 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 aforementioned 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 intermediate connection line 125 adjacent to the edge connection line 115 via the spacer 126. The connection structure 107 enables the intermediate connection line 125 adjacent to the edge connection line to collect the current collected by the edge connection line 115, thereby eliminating the need for welding on the edge connection line 115. This avoids the problem of cracking or microcracks at the edge of the back contact battery due to welding stress, thereby improving the yield of the photovoltaic module.

[0095] On one hand, the first gate line 103, electrically connected to the intermediate connecting line 125, includes two spaced-apart first main body portions 113 and a first connecting portion 123 connecting the two first main body portions. The first connecting portion 123 does not make electrical contact with the first doped conductive layer 101, resulting in a smaller contact area between the first gate line 103 and the first doped conductive layer 101, thereby reducing 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 spaced-apart second main body portions 114 and a second connecting portion 124 connecting the two second main body portions 114. The second connecting portion 124 does not make electrical contact with the second doped conductive layer 102, resulting in a smaller contact area between the second gate line 104 and the second doped conductive layer 102, thereby reducing metal recombination between the second gate line 104 and the second doped conductive layer 102. Both of these aspects are beneficial for improving the performance of the back contact battery.

[0096] This disclosure also provides a photovoltaic module, which comprises multiple back-contact cells connected as provided in any of the foregoing embodiments. The photovoltaic module is used to convert received light energy into electrical energy. It should be noted that the parts that are the same as or corresponding to those in the foregoing embodiments can be referred to the corresponding descriptions in the foregoing embodiments, and will not be repeated hereafter.

[0097] Figure 10 This is a cross-sectional structural diagram of a photovoltaic module provided in an embodiment of this disclosure.

[0098] refer to Figure 10 The photovoltaic module includes: a battery string, which is formed by connecting back contact batteries 10 as described in any of the preceding embodiments; a solder ribbon 11 for connecting adjacent back contact batteries 10; an encapsulating film 12 for covering the surface of the battery string; and a cover plate 13 for covering the surface of the encapsulating film away from the battery string.

[0099] In some embodiments, the back contact battery 10 may also be an IBC (Interdigitated Back Contact), an HPBC (Hybrid Passivated Back Contact), a TBC battery combining TOPCon and IBC technologies, or an HBC battery combining HIT / HJT (Heterojunction Technology) and IBC technologies. Of course, it may also be other types of back contact batteries.

[0100] In some embodiments, the back contact battery 10 can be a single cell or a sliced ​​cell, where a sliced ​​cell refers to a cell formed by cutting a single cell. The back contact battery 10 is electrically connected in a single cell or in multiple slices to form multiple battery strings, which are electrically connected in series and / or in parallel.

[0101] The solder ribbon 11 is used to connect adjacent back contact cells 10 and to transmit the current collected on the back contact cells 10 connected to the solder ribbon 11 to the assembly end connected to the cell string. One end of the solder ribbon 11 is electrically connected to a first grid line of a back contact cell 10, and the other end of the solder ribbon 11 is electrically connected to a second grid line of an adjacent back contact cell 10.

[0102] In some embodiments, the encapsulating film 12 includes a first encapsulating layer and a second encapsulating layer. The first encapsulating layer covers one of the front or back sides of the back contact battery 10, and the second encapsulating layer covers the other of the front or back sides of the back contact battery 10. Specifically, at least one of the first encapsulating layer or the second encapsulating layer can be an organic encapsulating film such as polyvinyl butyral (PVB) film, ethylene-vinyl acetate copolymer (EVA) film, polyvinyl octene coelastomer (POE) film, or polyethylene terephthalate (PET) film. Alternatively, at least one of the first encapsulating layer or the second encapsulating layer can also be an EP film, EPE film, or 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 sequentially stacking EVA film, POE film, and EVA film; and PVP film refers to a co-extruded film formed by stacking POE film, EVA film, and POE film. Co-extruded films can be manufactured by sequentially extruding one or more raw materials onto another pre-made film during the film processing, or by bonding different types of pre-made films together.

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

[0105] In some embodiments, the cover plate 13 can be a glass cover plate, a plastic cover plate, or other cover plate with light-transmitting function. Specifically, the surface of the cover plate facing the encapsulating film can be an uneven surface or a textured surface containing multiple raised structures, thereby increasing the utilization rate of incident light. The cover plate 13 includes a first cover plate and a second cover plate, the first cover plate being opposite to the first encapsulation layer, and the second cover plate being opposite to the second encapsulation layer.

[0106] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of this disclosure. Any person skilled in the art can make various alterations and modifications without departing from the spirit and scope of this disclosure; therefore, the scope of protection of this disclosure should be determined by the scope defined in the claims.

Claims

1. A back-contact battery, characterized in that, include: A substrate having opposing first and second surfaces, the second surface having a first edge; A first doped conductive layer and a second doped conductive layer are alternately distributed on the second surface. The doping elements in the first doped conductive layer and the doping elements in the second doped conductive layer have different conductivity types. The first gate line and the second gate line are alternately arranged along the first direction, at least a portion of the first gate line is in electrical contact with the first doped conductive layer, and at least a portion of the second gate line is in electrical contact with the second doped conductive layer; A first connecting line and a second connecting line are alternately arranged along a second direction. The first connecting line is electrically connected to the first gate line. The first connecting line includes an edge connecting line and a middle connecting line. No welding part is provided on the edge connecting line. The second connecting line adjacent to the edge connecting line includes a functional part and a spacing part. The functional part is connected to the second gate line. A connection structure, wherein one end of the connection structure is electrically connected to the edge connection line, and the other end is electrically connected to the intermediate connection line adjacent to the edge connection line through the interval portion; The first gate line electrically connected to the intermediate connecting line includes two first main body portions spaced apart and a first connecting portion connecting the two first main body portions. The first connecting portion does not make electrical contact with the first doped conductive layer. The second gate line includes two second main body portions spaced apart and a second connecting portion connecting the two second main body portions. The second connecting portion does not make electrical contact with the second doped conductive layer.

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

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

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

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

6. The back contact battery according to claim 1, characterized in that, Along the second direction, the distance between the edge connecting line and the adjacent second connecting line is the first spacing, and the distance between the second connecting line adjacent to the edge connecting line and the adjacent middle connecting line is the second spacing, wherein the first spacing is less than the second spacing.

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

8. The back contact battery according to claim 1, characterized in that, The back contact battery also includes: The first pad is located at the junction of a portion of the first connection line and the first gate line, and is electrically connected to the first connection line and the first gate line. The second pad is located at the junction of a portion of the second connection line and the second gate line, and is electrically connected to the second connection 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 5mm to 15mm, and the distance between the second pad adjacent to the third edge and the first gate line adjacent to the third edge is 5mm to 15mm.

10. 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 9; Solder strips, the solder strips being used to connect adjacent back contact batteries; An encapsulating film is used to cover the surface of the battery string; A cover plate is used to cover the surface of the encapsulating film that faces away from the battery string.

Images