Back contact cell and photovoltaic module

Abstract

The embodiment of the invention relates to the field of photovoltaic technology, provides a back contact battery and a photovoltaic module, and at least can improve the efficiency of the back contact battery. The back surface of the back contact battery comprises fine grids, main grids, edge bonding pads, connecting lines and penetrating lines, each main grid is electrically connected with a plurality of fine grids which are arranged in the second direction and have the same polarity, the main grids located on the edges of the two sides of the back contact battery in the first direction are edge main grids, and the other main grids are middle main grids; the edge bonding pads are located on the edges of the two sides of the back contact battery in the first direction, and the distance between the edge bonding pads and the edges of the back contact battery is larger than that between the edge main grids and the edges of the back contact battery; two ends of the connecting line are respectively connected with the edge bonding pad and the edge main grid; the through line is connected with the edge main grid and at least one middle main grid with the same grid polarity as the edge main grid; in the second direction, a width of the through line is greater than a width of the connecting line.

Description

Technical Field

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

[0002] As fossil energy is gradually depleted, 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] A back-contact solar cell is a cell in which both the positive and negative grid lines are placed on the back side of the cell (non-light-receiving side). The light-receiving side of the cell is not blocked by any metal grid lines, which effectively increases the short-circuit current of the back-contact cell. At the same time, the back side can allow wider metal grid lines to reduce the series resistance and thus increase the fill factor. This type of cell with no obstruction on the front side not only has a high conversion efficiency, but also looks more beautiful. At the same time, components with full back electrodes are easier to assemble.

[0004] However, the back-contact solar cell has a weak ability to collect current, which affects the improvement of the photoelectric conversion efficiency of the back-contact solar cell. Summary of the invention

[0005] The embodiments of the present application provide a back-contact cell and a photovoltaic module, which are at least beneficial to improving the efficiency of the back-contact cell.

[0006] According to some embodiments of the present application, on one hand, the embodiments of the present application provide a back-contact battery, which includes: a plurality of fine grids extending along a first direction, and fine grids of different polarities are alternately arranged along a second direction; a plurality of main grids extending along a second direction, and main grids of different polarities are alternately arranged along the first direction, each main grid is electrically connected to a plurality of fine grids of the same polarity arranged along the second direction, wherein the main grids located at the edges of both sides of the back-contact battery along the first direction are edge main grids, and the remaining main grids are intermediate main grids, each intermediate main grid has a plurality of intermediate pads, and along the first direction, the width of the intermediate pads is greater than the width of the intermediate main grid, and at least the intermediate main grid closest to the edge main grid includes a plurality of intermediate pads. The invention comprises a plurality of intermittent main grids arranged at intervals, each of which has at least one middle pad; an edge pad, which is located at the edges of the back contact battery on both sides along the first direction, and the distance between the edge pad and the edge of the back contact battery is greater than the distance between the edge main grid and the edge of the back contact battery; a connecting line, which extends along the first direction, and the two ends of the connecting line are respectively connected to the edge pad and the edge main grid; a through line, which extends along the first direction, and the through line connects the edge main grid and at least one middle main grid with the same properties as the edge main grid, and the intermittent main grid is located on both sides of the through line along the second direction; in the second direction, the width of the connecting line and the width of the through line are both greater than the width of the fine grid, and the width of the through line is greater than the width of the connecting line.

[0007] In some embodiments, along the second direction, the total number of edge pads is less than the number of middle pads corresponding to any middle busbar.

[0008] In some embodiments, a portion of the intermediate bus bars includes a plurality of discontinuous bus bars, and along the first direction, a width of the discontinuous bus bars is smaller than a width of the remaining intermediate bus bars.

[0009] In some embodiments, the length of the interrupted main gate along the second direction is smaller than the length of the penetration line along the first direction, and the width of the interrupted main gate along the first direction is smaller than the width of the penetration line along the second direction.

[0010] In some embodiments, along the first direction, the width of the edge bus bars is greater than the width of the discontinuous bus bars, and less than the width of the remaining intermediate bus bars.

[0011] In some embodiments, all intermediate main grids include multiple discontinuous main grids, each through-line connects multiple discontinuous main grids with the same polarity arranged along the first direction, and the width of the through-line along the second direction is greater than the width of the discontinuous main grid along the first direction.

[0012] In some embodiments, there are two penetration lines between adjacent discontinuous main bars along the second direction, and the two penetration lines are respectively connected to discontinuous main bars with different polarities.

[0013] In some embodiments, along the first direction, the width of the edge bus gate is greater than the width of the discontinuous bus gate.

[0014] In some embodiments, the edge main grid includes a first part spaced apart from each other and a second part located on both sides of the first part along the second direction, a through line is connected to the first part, a connecting line is connected to the second part, a fine grid located at the edge of the back contact battery along the first direction, a fine grid near the corner of the back contact battery is connected to the second part, and a fine grid near the middle of the back contact battery is connected to the edge pad or to the first part.

[0015] According to some embodiments of the present application, on the other hand, the embodiments of the present application further provide a photovoltaic module, including: a plurality of back contact cells as in the above embodiments; a welding strip, the welding strip connecting the pads or edge pads of adjacent back contact cells; an adhesive film, the adhesive film covering the surface of the back contact cell; and a cover plate, the cover plate being located on the surface of the adhesive film away from the back contact cell.

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

[0017] On the back side of the back contact battery provided by the embodiment of the present application, the fine grids of the first polarity and the fine grids of the second polarity are arranged alternately along the second direction, the fine grids of the first polarity are used to collect one of the electrons or holes in the back contact battery, and the main grid of the first polarity is used to collect the carriers on the fine grids of the first polarity; the fine grids of the second polarity are used to collect the other of the electrons or holes in the back contact battery, and the main grid of the second polarity is used to collect the carriers on the fine grids of the second polarity. The middle main grid has a middle pad, which is used to be welded with a welding strip to transmit the current on the middle main grid; the edge main grid is connected to the edge pad via a connecting wire, and the edge pad is used to be welded with a welding strip to transmit the current on the edge main grid. The distance between the edge pad and the edge of the back contact battery is greater than the distance between the edge main grid and the edge of the back contact battery. In this way, the edge pad can be prevented from being too close to the edge of the back contact battery, resulting in excessive welding stress and the occurrence of back contact battery fragments. However, it will also increase the distance between carriers on the edge main grid, thereby reducing the transmission efficiency. Therefore, in the back contact battery provided by the embodiment of the present application, the edge main grid is also connected to at least one intermediate main grid with the same polarity as the edge main grid through a through line. In this way, the carriers on the edge main grid can be transferred to the welding strip corresponding to the edge main grid through the edge pad, and can also be transferred to at least one intermediate main grid with the same polarity through the through line, and then transferred to the welding strip through the intermediate main grid, so as to improve the carrier transmission efficiency of the edge main grid. Among them, since the through line and the connecting line are both connected to the edge main grid, the carriers of multiple fine grids are collected on the edge main grid, and the width of the through line and the connecting line are set to be greater than the width of the fine grid, which is conducive to reducing the internal resistance of the through line and the connecting line, thereby improving the carrier transmission efficiency. In addition, since the length of the through-line is longer than that of the connecting line, the carrier transmission path is longer, and setting the width of the through-line to be greater than the width of the connecting line is beneficial to improving the transmission efficiency of carriers in the through-line. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. 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 application 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figures 1 to 5 Schematic diagram of the structures of various back-contact batteries provided in the embodiments of the present application. DETAILED DESCRIPTION

[0020] As known from the background technology, the back-contact solar cell has a weak ability to collect current, which affects the improvement of the photoelectric conversion efficiency of the back-contact solar cell.

[0021] The present application provides a back-contact cell and a photovoltaic module, which at least helps to improve the efficiency of the back-contact cell.

[0022] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features.

[0023] In the description of the embodiments of the present application, “plurality” means more than two, unless otherwise clearly and specifically defined.

[0024] 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 application. The appearance of the phrase in various locations 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.

[0025] In the description of the embodiments of the present application, 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 can 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.

[0026] In the description of the embodiments of the present application, 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", "circumferential", etc., indicating orientations or positional relationships, 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 application and simplifying the description, and 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 cannot be understood as a limitation on the embodiments of the present application.

[0027] In the description of the embodiments of the present application, 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 application can be understood according to the specific circumstances.

[0028] In the description of the embodiments of the present application, when a certain component “includes” another component, unless otherwise stated, other components are not excluded and other components may be further included.

[0029] The terms used in the description of the various described embodiments herein are used only to describe specific embodiments and are not intended to be limiting. As used in the description of the various described embodiments and the appended claims, "components" are also intended to include plural forms unless the context clearly indicates otherwise.

[0030] The following will describe the various embodiments of the present application 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 application, many technical details are provided in order to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solution claimed in the present application can be implemented.

[0031] Figures 1 to 5 Schematic diagram of the structures of various back-contact batteries provided in the embodiments of the present application.

[0032] refer to Figures 1 to 5 The back-contact cell provided in the embodiment of the present application has a front side and a back side, the front side is a light-receiving side, and the back side is a backlighting side. The back side of the back-contact cell includes: a plurality of fine grids 110, a plurality of main grids 120, an edge pad 130, a connecting line 140 and a through line 150.

[0033] The fine grids 110 extend along the first direction X, and the fine grids 110 of different polarities are alternately arranged along the second direction Y. Specifically, the fine grids 110 of the first polarity and the fine grids 110 of the second polarity are alternately arranged along the second direction Y, the first polarity is one of the positive polarity or the negative polarity, and the second polarity is the other of the positive polarity or the negative polarity.

[0034] The main grid 120 extends along the second direction Y, and the main grids 120 of different polarities are alternately arranged along the first direction X, and each main grid 120 is electrically connected to a plurality of fine grids 110 of the same polarity arranged along the second direction Y. Specifically, the main grid 120 of the first polarity and the main grid 122 of the second polarity are alternately arranged along the second direction Y, the main grid 120 of the first polarity is electrically connected to a plurality of fine grids 110 of the first polarity arranged along the second direction Y, and the main grid 122 of the second polarity is electrically connected to a plurality of fine grids 110 of the second polarity arranged along the second direction Y. Among them, the main grids 120 located at the edges of both sides of the back contact cell along the first direction X are edge main grids 123, and the remaining main grids 120 are intermediate main grids 124, the edge main grid 123 can have the first polarity or the second polarity, and the intermediate main grid 124 can have the first polarity or the second polarity. Each intermediate main grid 124 has a plurality of intermediate pads 125 . Along the first direction X, the width of the intermediate pads 125 is greater than the width of the intermediate main grid 124 . At least the intermediate main grid 124 closest to the edge main grid 123 includes a plurality of intermittent main grids 126 arranged at intervals, and each intermittent main grid 126 has at least one intermediate pad 125 .

[0035] The edge pad 130 is located at the two side edges of the back contact battery along the first direction X. The distance between the edge pad 130 and the edge of the back contact battery is greater than the distance between the edge main grid 123 and the edge of the back contact battery. The connecting line 140 extends along the first direction X. The two ends of the connecting line 140 are respectively connected to the edge pad 130 and the edge main grid 123.

[0036] In this embodiment, for easy distinction, the middle pad 125 or edge pad 130 filled with black is the pad corresponding to the main grid 120 of the first polarity, and the middle pad 125 or edge pad 130 filled with white is the pad corresponding to the main grid 120 of the second polarity.

[0037] The through line 150 extends along the first direction X, and the through line 150 connects the edge main grid 123 and at least one intermediate main grid 124 having the same polarity as the edge main grid 123, and the intermittent main grid 126 is located on both sides of the through line 150 along the second direction Y. In the second direction Y, the width of the connecting line 140 and the width of the through line 150 are both greater than the width of the fine grid 110, and the width of the through line 150 is greater than the width of the connecting line 140.

[0038] On the back side of the back contact battery provided by the embodiment of the present application, the fine grid 110 of the first polarity and the fine grid 110 of the second polarity are arranged alternately along the second direction Y. The fine grid 110 of the first polarity is used to collect one of the electrons or holes in the back contact battery, and the main grid 120 of the first polarity is used to collect the carriers on the fine grid 110 of the first polarity; the fine grid 110 of the second polarity is used to collect the other of the electrons or holes in the back contact battery, and the main grid 120 of the second polarity is used to collect the carriers on the fine grid 110 of the second polarity. The middle main grid 124 has a middle pad 125, and the middle pad 125 is used to be welded with a welding strip to transmit the current on the middle main grid 124; the edge main grid 123 is connected to the edge pad 130 through a connecting wire 140, and the edge pad 130 is used to be welded with a welding strip to transmit the current on the edge main grid 123. The distance between the edge pad 130 and the edge of the back contact battery is greater than the distance between the edge main grid 123 and the edge of the back contact battery. In this way, the edge pad 130 can be prevented from being too close to the edge of the back contact battery, resulting in excessive welding stress and the occurrence of back contact battery fragments. However, it will also increase the distance between carriers on the edge main grid 123, thereby reducing the transmission efficiency. Therefore, in the back contact battery provided in the embodiment of the present application, the edge main grid 123 is also connected to at least one intermediate main grid 124 with the same polarity as the edge main grid 123 through a through line 150. In this way, the carriers on the edge main grid 123 can be transferred to the welding strip corresponding to the edge main grid 123 through the edge pad 130, and can also be transferred to at least one intermediate main grid 124 with the same polarity through the through line 150, and then transferred to the welding strip via the intermediate main grid 124, so as to improve the carrier transmission efficiency of the edge main grid 123. Among them, since the through-line 150 and the connecting line 140 are both connected to the edge main grid 123, the carriers of multiple fine grids 110 are collected on the edge main grid 123, and the width of the through-line 150 and the connecting line 140 are set to be larger than the width of the fine grid 110, which is conducive to reducing the internal resistance of the through-line 150 and the connecting line 140, thereby improving the carrier transmission efficiency. In addition, since the length of the through-line 150 is longer than the length of the connecting line 140, the carrier transmission path is longer, and setting the width of the through-line 150 to be larger than the width of the connecting line 140 is conducive to improving the transmission efficiency of the carriers in the through-line 150.

[0039] In some embodiments, the back contact cell can be an IBC cell (Interdigitated Back Contact), an HPBC cell (Hybrid Passivated Back Contact), a TBC cell that stacks TOPCon (Tunnel Oxide Passivated Contact) technology and IBC technology, or an HBC cell that stacks HIT / HJT (Heterojunction Technology) technology and IBC technology. Of course, it can also be other types of back contact cells.

[0040] In some embodiments, the type of the back contact cell can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, an amorphous silicon solar cell or a multi-compound solar cell. The multi-compound solar cell can specifically be a cadmium sulfide solar cell, a gallium arsenide solar cell, a copper indium selenide solar cell or a perovskite solar cell.

[0041] refer to Figure 2 or Figure 5 In some embodiments, along the second direction Y, the total number of edge pads 130 is less than the number of intermediate pads 125 corresponding to any intermediate main grid 124. Since stress concentration is more likely to occur at the corners of the back contact battery, resulting in the fragmentation problem of the back contact battery, the reduction in the number of edge pads 130 can avoid setting the edge pads 130 at the corners of the back contact battery, thereby reducing the risk of fragmentation of the back contact battery. In addition, the carriers on the edge main grid 123 can be transferred to the welding strip corresponding to the edge main grid 123 through the edge pads 130, and can also be transferred to the welding strip corresponding to at least one intermediate main grid 124 with the same polarity through the through wire 150. Therefore, even if the number of edge pads 130 is reduced, the carrier collection efficiency on the edge fine grid 110 can still be kept high.

[0042] In some embodiments, reference Figure 1 , Figure 2 or Figure 4 , some of the intermediate main grids 124 include a plurality of discontinuous main grids 126, and the remaining intermediate main grids 124 are a whole main grid; in other embodiments, refer to Figure 3 , all the intermediate main grids 124 may include a plurality of discontinuous main grids 126 .

[0043] When a portion of the intermediate bus bars 124 include a plurality of discontinuous bus bars 126, the width of the discontinuous bus bars 126 may be smaller than the width of the remaining intermediate bus bars 124 along the first direction X. Since the number of fine grids 110 connected to the discontinuous bus bars 126 is relatively small compared to the remaining intermediate bus bars 124, setting the width of the discontinuous bus bars 126 smaller than the width of the remaining intermediate bus bars 124 can save the slurry use cost while maintaining the discontinuous bus bars 126 with a high carrier transmission efficiency.

[0044] When a portion of the intermediate main grids 124 includes a plurality of discontinuous main grids 126, the width of the discontinuous main grid 126 along the first direction X and the width of the through line 150 along the second direction Y may be determined according to the length of the discontinuous main grid 126 and the length of the through line 150. For example, when the length of the discontinuous main grid 126 along the second direction Y is less than the length of the through line 150 along the first direction X, the width of the discontinuous main grid 126 along the first direction X may be set to be less than the width of the through line 150 along the second direction Y; when the length of the discontinuous main grid 126 along the second direction Y is greater than the length of the through line 150 along the first direction X, the width of the discontinuous main grid 126 along the first direction X may be set to be greater than the width of the through line 150 along the second direction Y. The longer the length of the intermittent main grid 126 or the length of the through line 150, the longer the corresponding transmission path. The width of the intermittent main grid 126 and the width of the through line 150 are determined according to the length of the intermittent main grid 126 and the length of the through line 150. This can save the cost of using the slurry while maintaining a high carrier transmission efficiency for both the intermittent main grid 126 and the through line 150.

[0045] When a portion of the intermediate bus bars 124 include a plurality of discontinuous bus bars 126, the width of the edge bus bars 123 along the first direction X may be greater than the width of the discontinuous bus bars 126, and less than the width of the remaining intermediate bus bars 124. The carriers on the edge bus bars 123 may be transferred to the welding strip corresponding to the edge bus bars 123 through the edge pads 130, and may also be transferred to the welding strip corresponding to at least one intermediate bus bar 124 with the same polarity through the through wires 150. Therefore, there are more carrier transmission paths on the edge bus bars 123, and the carrier load on the edge bus bars 123 is smaller than that of the intermediate bus bars 124 that do not include the discontinuous bus bars 126. Therefore, the width of the edge bus bars 123 may be smaller than that of the intermediate bus bars 124 that do not include the discontinuous bus bars 126; and when the length of the edge bus bars 123 is longer than that of the discontinuous bus bars 126, the width of the edge bus bars 123 needs to be larger than that of the discontinuous bus bars 126 to meet the requirement of low internal resistance.

[0046] When all the intermediate main grids 124 include a plurality of discontinuous main grids 126, each through-line 150 is connected to a plurality of discontinuous main grids 126 of the same polarity arranged along the first direction X, and the width of the through-line 150 along the second direction Y is greater than the width of the discontinuous main grid 126 along the first direction X. In other words, the through-line 150 passes through the entire back contact cell along the first direction X, so that the plurality of discontinuous main grids 126 of the same polarity arranged along the first direction X are interconnected, and the carrier transmission path and efficiency on the fine grid 110 are improved. The through-line 150 is relatively long, and the width of the through-line 150 along the second direction Y is greater than the width of the discontinuous main grid 126 along the first direction X, which can reduce the internal resistance of the through-line 150 itself, maintain the through-line 150 with a high carrier transmission efficiency, and reduce the slurry cost of the discontinuous main grid 126.

[0047] refer to Figure 3 In some embodiments, there are two through-wires 150 between adjacent discontinuous main gates 126 along the second direction Y, and the two through-wires 150 are respectively connected to discontinuous main gates 126 with different polarities.

[0048] refer to Figure 4 In some other embodiments, there may be only one through-line 150 between adjacent discontinuous main gates 126 along the second direction Y. In the second direction Y, the polarities of adjacent through-lines 150 may be the same or different.

[0049] When all the intermediate bus bars 124 include a plurality of discontinuous bus bars 126, the width of the edge bus bars 123 is greater than the width of the discontinuous bus bars 126 along the first direction X. Along the second direction Y, the length of the edge bus bars 123 is longer than that of the intermediate bus bars 124, and the edge bus bars 123 need to be set with a larger width to reduce the internal resistance.

[0050] exist Figures 1 to 4 In the example, the edge main grid 123 is a whole piece.

[0051] In other embodiments, reference Figure 5The edge main grid 123 includes a first part 1231 spaced apart from each other and a second part 1232 located on both sides of the first part 1231 along the second direction Y. The through line 150 is connected to the second part 1232, and the connecting line is connected to the first part 1231. Among the fine grids 110 located at the upper edge of the back contact battery along the first direction X, the fine grids 110 near the corners of the back contact battery are connected to the second part 1232, and the fine grids 110 near the middle of the back contact battery are connected to the edge pad 130 or to the first part 1231. In this way, no edge pad 130 is set at the corner position of the back contact battery, and the fine grid 110 at the corner is connected to other intermediate main grids 124 of the same polarity through the second part 1232 and the through line 150; the fine grid 110 located at the edge of the back contact battery along the first direction X and located in the middle of the back contact battery along the second direction Y is connected to the edge pad 130 through the first part 1231 and the connecting line 140, or is directly connected to the edge pad 130, and the carriers on the fine grid 110 at the edge of the back contact battery along the first direction X are collected through different paths respectively. On the one hand, the collection efficiency of the carriers on the fine grid 110 at the edge can be improved; on the other hand, it can avoid setting pads at the corners of the back contact battery to avoid stress concentration caused by the pads at the corners, which may cause fragmentation problems of the back contact battery.

[0052] When the edge busbar 123 includes the first portion 1231 and the second portion 1232, along the first direction X, the width of the first portion 1231 may be smaller than the width of the discontinuous busbar 126, and / or the width of the second portion 1232 may be smaller than the width of the discontinuous busbar 126. The length of the fine grid 110 connected to the first portion 1231 or the second portion 1232 is shorter than the length of the fine grid 110 connected to the discontinuous busbar 126, so the width of the first portion 1231 and / or the width of the second portion 1232 is smaller, which can help save the cost of using the slurry.

[0053] It should be noted that in the drawings provided in this embodiment, the number of fine gates 110, the number of main gates 120, the number of edge pads 130, the number of connecting lines 140 and the number of through lines 150 do not constitute limitations, and the number of fine gates 110, the number of main gates 120, the number of edge pads 130, the number of connecting lines 140 and the number of through lines 150 can be adjusted according to actual conditions.

[0054] On the back side of the back contact battery provided by the embodiment of the present application, the fine grid 110 of the first polarity and the fine grid 110 of the second polarity are arranged alternately along the second direction Y. The fine grid 110 of the first polarity is used to collect one of the electrons or holes in the back contact battery, and the main grid 120 of the first polarity is used to collect the carriers on the fine grid 110 of the first polarity; the fine grid 110 of the second polarity is used to collect the other of the electrons or holes in the back contact battery, and the main grid 120 of the second polarity is used to collect the carriers on the fine grid 110 of the second polarity. The middle main grid 124 has a middle pad 125, and the middle pad 125 is used to be welded with a welding strip to transmit the current on the middle main grid 124; the edge main grid 123 is connected to the edge pad 130 through a connecting wire 140, and the edge pad 130 is used to be welded with a welding strip to transmit the current on the edge main grid 123. The distance between the edge pad 130 and the edge of the back contact battery is greater than the distance between the edge main grid 123 and the edge of the back contact battery. In this way, the edge pad 130 can be prevented from being too close to the edge of the back contact battery, resulting in excessive welding stress and the occurrence of back contact battery fragments. However, it will also increase the distance between carriers on the edge main grid 123, thereby reducing the transmission efficiency. Therefore, in the back contact battery provided in the embodiment of the present application, the edge main grid 123 is also connected to at least one intermediate main grid 124 with the same polarity as the edge main grid 123 through a through line 150. In this way, the carriers on the edge main grid 123 can be transferred to the welding strip corresponding to the edge main grid 123 through the edge pad 130, and can also be transferred to at least one intermediate main grid 124 with the same polarity through the through line 150, and then transferred to the welding strip via the intermediate main grid 124, so as to improve the carrier transmission efficiency of the edge main grid 123. Among them, since the through-line 150 and the connecting line 140 are both connected to the edge main grid 123, the carriers of multiple fine grids 110 are collected on the edge main grid 123, and the width of the through-line 150 and the connecting line 140 are set to be larger than the width of the fine grid 110, which is conducive to reducing the internal resistance of the through-line 150 and the connecting line 140, thereby improving the carrier transmission efficiency. In addition, since the length of the through-line 150 is longer than the length of the connecting line 140, the carrier transmission path is longer, and setting the width of the through-line 150 to be larger than the width of the connecting line 140 is conducive to improving the transmission efficiency of the carriers in the through-line 150.

[0055] Correspondingly, another embodiment of the present application further provides a photovoltaic module, comprising: a plurality of back contact cells, welding strips, adhesive films and cover plates as in the above embodiment, the welding strips connecting the middle pads or edge pads of adjacent back contact cells; the adhesive film covering the surface of the back contact cells; the cover plate is located on the surface of the adhesive film away from the back contact cells. For the parts that are the same or corresponding to the previous embodiment, reference may be made to the corresponding description of the previous embodiment, and will not be described in detail below.

[0056] The material of the film can be an organic encapsulation film such as ethylene-vinyl acetate copolymer (EVA) film, polyethylene octene co-elastomer (POE) film or polyvinyl butyral (PVB) film.

[0057] The cover plate can be a glass cover plate, a plastic cover plate or the like with a light-transmitting function. In some embodiments, the surface of the cover plate facing the adhesive film can be a concave-convex surface, thereby increasing the utilization rate of the incident light.

[0058] Those skilled in the art will appreciate that the above-mentioned embodiments are specific examples for implementing the present application, and in practical applications, various changes may be made to the embodiments in form and detail without departing from the spirit and scope of the present application. Any person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present application, and therefore the scope of protection of the present application shall be subject to the scope defined in the claims.

Claims

1. A back contact battery, characterized in that: On the back side of the back contact battery, comprising: A plurality of fine grids, the fine grids extending along a first direction, and the fine grids of different polarities are alternately arranged along a second direction; a plurality of main grids, the main grids extending along the second direction, and the main grids of different polarities are alternately arranged along the first direction, each of the main grids being electrically connected to a plurality of fine grids of the same polarity arranged along the second direction, wherein the main grids located at the edges of both sides of the back contact battery along the first direction are edge main grids, and the remaining main grids are intermediate main grids, each of the intermediate main grids having a plurality of intermediate pads, and along the first direction, the width of the intermediate pads is greater than the width of the intermediate main grid, and at least the intermediate main grid closest to the edge main grid includes a plurality of intermittent main grids arranged at intervals, and each of the intermittent main grids has at least one intermediate pad; An edge pad, wherein the edge pad is located at both side edges of the back contact cell along the first direction, and the distance between the edge pad and the edge of the back contact cell is greater than the distance between the edge main grid and the edge of the back contact cell; A connecting line, the connecting line extending along the first direction, two ends of the connecting line being respectively connected to the edge pad and the edge main grid; A through line extending along the first direction, the through line connecting the edge main grid and at least one intermediate main grid having the same property as the edge main grid, and the discontinuous main grids are located at both sides of the through line along the second direction; Along the second direction, the width of the connecting line and the width of the penetrating line are both greater than the width of the fine gate, and the width of the penetrating line is greater than the width of the connecting line.

2. The back contact cell according to claim 1, characterized in that: Along the second direction, the total number of the edge pads is less than the number of the middle pads corresponding to any one of the middle main grids.

3. The back contact cell according to claim 1, characterized in that: A portion of the intermediate main grids includes a plurality of discontinuous main grids, and along the first direction, a width of the discontinuous main grid is smaller than a width of the remaining intermediate main grids.

4. The back contact cell according to claim 3, characterized in that: The length of the interrupted main grid along the second direction is smaller than the length of the penetration line along the first direction, and the width of the interrupted main grid along the first direction is smaller than the width of the penetration line along the second direction.

5. The back contact battery according to claim 3, characterized in that: Along the first direction, the width of the edge main grid is greater than the width of the discontinuous main grid, and smaller than the width of the remaining intermediate main grids.

6. The back contact cell according to claim 1, characterized in that: All of the intermediate main grids include multiple discontinuous main grids, each of the through-lines connects multiple discontinuous main grids with the same polarity arranged along the first direction, and the width of the through-line along the second direction is greater than the width of the discontinuous main grid along the first direction.

7. The back contact cell according to claim 6, characterized in that: There are two penetration lines between the adjacent discontinuous main grids along the second direction, and the two penetration lines are respectively connected to the discontinuous main grids with different polarities.

8. The back contact cell according to claim 6, characterized in that: Along the first direction, the width of the edge main grid is greater than the width of the discontinuous main grid.

9. The back contact cell according to claim 1, characterized in that: The edge main grid includes a first part spaced apart from each other and a second part located on both sides of the first part along the second direction, the through line is connected to the first part, the connecting line is connected to the second part, and among the fine grids located at the edge of the back contact battery along the first direction, the fine grids near the corners of the back contact battery are connected to the second part, and the fine grids near the middle of the back contact battery are connected to the edge pad or to the first part.

10. A photovoltaic module, characterized in that: include: A plurality of back contact cells as claimed in any one of claims 1 to 9; A soldering strip, the soldering strip connecting the soldering pads or edge soldering pads of adjacent back contact cells; An adhesive film, the adhesive film covering the surface of the back contact battery; A cover plate is located on a surface of the adhesive film away from the back contact battery.

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