Back contact cells and photovoltaic modules

Abstract

The embodiment of the present application relates to the photovoltaic technical field, provide a kind of back contact cell and photovoltaic module, at least can improve the efficiency of back contact cell.The back of back contact cell includes: fine grid, main grid, edge pad, connecting line and through line, each main grid is electrically connected with the fine grid of same polarity arranged in the second direction, the main grid located in the two side edges of back contact cell in the first direction is edge main grid, and the rest main grid is intermediate main grid;Edge pad is located in the two side edges of back contact cell in the first direction, and the distance between edge pad and the edge of back contact cell is greater than the distance between edge main grid and the edge of back contact cell;The two ends of connecting line are connected with edge pad and edge main grid respectively;Through line connects edge main grid and at least one intermediate main grid of same polarity with edge main grid;In the second direction, the width of through line is greater than the width of connecting line.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of photovoltaic technology, and particularly relate to a back contact cell and a photovoltaic module. BACKGROUND

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

[0003] A back contact solar cell is a cell in which the positive grid lines and the negative grid lines are both placed on the back (non-light receiving surface) of the cell. The light receiving surface of the cell has no metal grid lines to block, thereby effectively increasing the short-circuit current of the back contact cell. Meanwhile, the back surface can accommodate wider metal grid lines to reduce the series resistance and thereby improve the fill factor. Moreover, such a cell without shading on the front surface not only has high conversion efficiency, but also looks more beautiful, and a module with full back electrodes is easier to assemble.

[0004] However, the back contact solar cell has weak current collection ability, thereby affecting the improvement of the photoelectric conversion efficiency of the back contact solar cell. SUMMARY

[0005] Embodiments of the present application provide a back contact cell and a photovoltaic module, which at least facilitate the improvement of the efficiency of the back contact cell.

[0006] According to some embodiments of the present application, the present application provides a back contact battery, on the back of the back contact battery, comprising: a plurality of fine grids, the fine grids extending along a first direction, and fine grids of different polarities being arranged alternately along a second direction; a plurality of main grids, the main grids extending along the second direction, and main grids of different polarities being arranged alternately along the first direction, each main grid being electrically connected with a plurality of fine grids of the same polarity arranged along the second direction, wherein the main grids located at the edges 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 having a plurality of intermediate pads, the width of the intermediate pads being greater than the width of the intermediate main grid along the first direction, at least the intermediate main grids closest to the edge main grids comprising a plurality of spaced apart discontinuous main grids, each discontinuous main grid having at least one intermediate pad; edge pads, the edge pads being located at the edges of the back contact battery along the first direction, the distance between the edge pads and the edge of the back contact battery being greater than the distance between the edge main grids and the edge of the back contact battery; connection lines, the connection lines extending along the first direction, the two ends of the connection lines being connected with the edge pads and the edge main grids respectively; through lines, the through lines extending along the first direction, the through lines connecting the edge main grids and at least one intermediate main grid of the same polarity as the edge main grids, the discontinuous main grids being located on both sides of the through lines along the second direction; along the second direction, the width of the connection lines and the width of the through lines are both greater than the width of the fine grids, and the width of the through lines is greater than the width of the connection lines.

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

[0008] In some embodiments, a part of the number of intermediate main grids comprises a plurality of discontinuous main grids, along the first direction, the width of the discontinuous main grids is less than the width of the remaining intermediate main grids.

[0009] In some embodiments, the length of the discontinuous main grid along the second direction is less than the length of the through line along the first direction, and the width of the discontinuous main grid along the first direction is less than the width of the through line along the second direction.

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

[0011] In some embodiments, all intermediate main grids comprise a plurality of discontinuous main grids, each through line connecting a plurality of discontinuous main grids of the same polarity arranged along the first direction, the width of the through line along the second direction being greater than the width of the discontinuous main grid along the first direction.

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

[0013] In some embodiments, the width of the edge main grid is greater than the width of the discontinuous main grid in the first direction.

[0014] In some embodiments, the edge main grid comprises first sections spaced apart from each other and second sections located on both sides of the first sections in the second direction, the through lines are connected to the first sections, the connecting lines are connected to the second sections, the fine grids located at the edges of the back contact cells in the first direction are connected to the second sections, the fine grids located close to the corners of the back contact cells are connected to the second sections, and the fine grids located close to the middle of the back contact cells are connected to the edge pads or the first sections.

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

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

[0017] The back surface of the back contact battery provided in the embodiment of the present application is provided with fine grids of a first polarity and fine grids of a second polarity, which are arranged alternately along a second direction, the fine grids of the first polarity are used to collect one of electrons or holes in the back contact battery, and the main grids of the first polarity are used to concentrate 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 grids of the second polarity are used to concentrate the carriers on the fine grids of the second polarity. The intermediate main grid is provided with an intermediate pad, which is used to be welded with a solder strip to transmit the current on the intermediate main grid; the edge main grid is connected with an edge pad through a connecting line, and the edge pad is used to be welded with a solder 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, so that the problem of the back contact battery fragmentation caused by the excessive welding stress of the edge pad due to the fact that the edge pad is too close to the edge of the back contact battery can be avoided, but at the same time, the distance of the carriers on the edge main grid is increased, which further leads to the decrease of the transmission efficiency. Therefore, the edge main grid of the back contact battery provided in the embodiment of the present application is further connected with at least one intermediate main grid with the same polarity as the edge main grid through a penetrating line, so that the carriers on the edge main grid can be transmitted to the solder strip corresponding to the edge main grid through the edge pad, and can also be transmitted to at least one intermediate main grid with the same polarity as the edge main grid through the penetrating line, and then transmitted to the solder strip through the intermediate main grid, so as to improve the carrier transmission efficiency of the edge main grid. Since the penetrating line and the connecting line are both connected with the edge main grid, the carriers of multiple fine grids are collected on the edge main grid, and the width of the penetrating line and the connecting line is greater than the width of the fine grid, which is beneficial to reduce the internal resistance of the penetrating line and the connecting line, and further improve the carrier transmission efficiency. In addition, since the length of the penetrating line is longer than the length of the connecting line, the carrier transmission path is longer, and the width of the penetrating line is greater than the width of the connecting line, which is beneficial to improve the transmission efficiency of the carriers in the penetrating line. BRIEF DESCRIPTION OF DRAWINGS

[0018] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which are illustrative of various embodiments of devices, systems, and methods. In the drawings, like references indicate similar elements in the various figures. Unless otherwise noted, the drawings provided herein are not to scale and are shown as simple schematic illustrations of embodiments of the present application. Unless specifically stated, the drawings are merely meant to be illustrative and not to be construed as limiting the scope of the present application. As such, one skilled in the art will readily appreciate that the concepts disclosed herein can be carried out with a variety of other systems, structures, and methods.

[0019] Figures 1 to 5 The structure schematic diagrams of various back contact batteries provided in the embodiment of the present application. DETAILED DESCRIPTION

[0020] As can be known from the background art, the back contact solar cell has weak current collection capability, thereby affecting 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, at least to improve the efficiency of the back contact cell.

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

[0023] In the description of the embodiments of the present application, the meaning of "a plurality of" is more than two, unless otherwise explicitly and specifically limited.

[0024] In this document, reference to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to each other. The skilled person explicitly and implicitly understands that the embodiments described herein can 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 the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of existence of A, existence of A and B, and existence of B. In addition, the character " / " in this document generally represents that the front and rear associated objects are in an "or" relationship.

[0026] In the description of the embodiments of the present application, the technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the embodiments of the present application.

[0027] In the description of the embodiments of the present application, unless specifically defined and limited otherwise, the terms "mounting", "connection", "connecting", "fixed", and the like should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrated; can be mechanical connection, can also be electrical connection; can be direct connection, can also be indirect connection through an intermediate medium, can be internal communication of two elements or interaction relationship between two elements. For those skilled 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 specified, other components are not excluded, and other components can also be further included.

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

[0030] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present application, many technical details are proposed in order to make the reader better understand the present application. However, the technical solutions claimed by the present application can be realized even without these technical details and various changes and modifications based on the following embodiments.

[0031] Figures 1 to 5 The structure schematic diagram of the back contact battery provided by the embodiments of the present application.

[0032] Reference Figures 1 to 5 The back contact battery provided by the embodiments of the present application has a front surface and a back surface, the front surface is a light receiving surface, and the back surface is a back light surface. The back surface of the back contact battery includes a plurality of fine grids 110, a plurality of main grids 120, an edge pad 130, a connecting wire 140 and a through wire 150.

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

[0034] The main grids 120 extend along the second direction Y, and the main grids 120 of different polarities are arranged alternately along the first direction X, each main grid 120 is electrically connected with a plurality of fine grids 110 of the same polarity arranged along the second direction Y. Specifically, the main grids 120 of the first polarity and the main grids 122 of the second polarity are arranged alternately along the second direction Y, the main grids 120 of the first polarity are electrically connected with a plurality of fine grids 110 of the first polarity arranged along the second direction Y, and the main grids 122 of the second polarity are electrically connected with a plurality of fine grids 110 of the second polarity arranged along the second direction Y. The main grids 120 located at the two side edges 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 grids 123 can have the first polarity or the second polarity, and the intermediate main grids 124 can have the first polarity or the second polarity. Each intermediate main grid 124 has a plurality of intermediate pads 125, and the width of the intermediate pads 125 is greater than the width of the intermediate main grid 124 along the first direction X, and at least the intermediate main grid 124 adjacent to the edge main grid 123 includes a plurality of spaced apart discontinuous main grids 126, and each discontinuous main grid 126 has at least one intermediate pad 125.

[0035] The edge pads 130 are located at the two side edges of the back contact cell along the first direction X, and the distance between the edge pads 130 and the edge of the back contact cell is greater than the distance between the edge main grid 123 and the edge of the back contact cell, and the connecting lines 140 extend along the first direction X, and the two ends of the connecting lines 140 are connected with the edge pads 130 and the edge main grid 123 respectively.

[0036] In the embodiment, for the convenience of distinction, the intermediate pads 125 or the edge pads 130 filled with black are the pads corresponding to the main grids 120 of the first polarity, and the intermediate pads 125 or the edge pads 130 filled with white are the pads corresponding to the main grids 120 of the second polarity.

[0037] The through lines 150 extend along the first direction X, and the through lines 150 connect the edge main grid 123 and at least one intermediate main grid 124 of the same polarity as the edge main grid 123, and the discontinuous main grids 126 are located on both sides of the through line 150 along the second direction Y. Along 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] The back surface of the back contact battery provided by the embodiment of the present application is provided with the fine grid 110 of the first polarity and the fine grid 110 of the second polarity which are alternately arranged along the second direction Y, the fine grid 110 of the first polarity is used to collect one of the electrons or the holes in the back contact battery, 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 the 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 intermediate pad 125 is arranged on the intermediate main grid 124, and the intermediate pad 125 is used to be welded with the solder strip to transmit the current on the intermediate main grid 124 outwards; the edge main grid 123 is connected with the edge pad 130 through the connecting line 140, and the edge pad 130 is used to be welded with the solder strip to transmit the current on the edge main grid 123 outwards. 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, so that the problem of the back contact battery fragments caused by the excessive welding stress of the edge pad 130 which is too close to the edge of the back contact battery can be avoided, but at the same time, the distance of the carriers on the edge main grid 123 is increased, and the transmission efficiency is reduced; therefore, the edge main grid 123 on the back contact battery provided by the embodiment of the present application is connected with at least one intermediate main grid 124 which has the same polarity as the edge main grid 123 through the penetrating line 150, so that the carriers on the edge main grid 123 can be transmitted to the solder strip corresponding to the edge main grid 123 through the edge pad 130, and can also be transmitted to at least one intermediate main grid 124 which has the same polarity as the edge main grid 123 through the penetrating line 150, and then transmitted to the solder strip through the intermediate main grid 124, so as to improve the carrier transmission efficiency of the edge main grid 123. Since the penetrating line 150 and the connecting line 140 are both connected with the edge main grid 123, the carriers of the plurality of fine grids 110 are collected on the edge main grid 123, and the width of the penetrating line 150 and the connecting line 140 is greater than the width of the fine grid 110, which is beneficial to reduce the internal resistance of the penetrating line 150 and the connecting line 140, and further improve the carrier transmission efficiency. In addition, since the length of the penetrating line 150 is longer than the length of the connecting line 140, the carrier transmission path is longer, and the width of the penetrating line 150 is greater than the width of the connecting line 140, which is beneficial to improve the transmission efficiency of the carriers in the penetrating 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 stacked with TOPCon (Tunnel Oxide Passivated Contact) and IBC technologies, or an HBC cell stacked with HIT / HJT (Heterojunction Technology) and IBC technologies, and of course other types of back contact cells.

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

[0041] Reference Figure 2 Or Figure 5 In some embodiments, the total number of edge pads 130 in the second direction Y is less than the number of middle pads 125 corresponding to any middle busbar 124. Since the corner position of the back contact cell is more prone to stress concentration leading to the fragmentation problem of the back contact cell, reducing the number of edge pads 130 can avoid setting edge pads 130 at the corner position of the back contact cell, thereby reducing the risk of fragmentation of the back contact cell. In addition, the carriers on the edge busbar 123 can be transmitted to the solder ribbon corresponding to the edge busbar 123 through the edge pad 130, and also transmitted to the solder ribbon corresponding to at least one middle busbar 124 with the same polarity through the through-wire 150, so that even if the number of edge pads 130 is reduced, the carrier collection efficiency on the edge fine grid 110 can still be high.

[0042] In some embodiments, referring to Figure 1 , Figure 2 Or Figure 4 , a part of the number of middle busbars 124 includes a plurality of intermittent busbars 126, and the rest of the middle busbars 124 are whole; in other embodiments, referring to Figure 3 , all of the middle busbars 124 can include a plurality of intermittent busbars 126.

[0043] When the partial number of the intermediate main grids 124 include the plurality of the interrupted main grids 126, the width of the interrupted main grid 126 in the first direction X can be smaller than the width of the remaining intermediate main grid 124. Since the number of the fine grids 110 connected by the interrupted main grid 126 is relatively small compared to the remaining intermediate main grid 124, the width of the interrupted main grid 126 can be set to be smaller than the width of the remaining intermediate main grid 124 to save the cost of the paste while maintaining the high carrier transport efficiency of the interrupted main grid 126.

[0044] When the partial number of the intermediate main grids 124 include the plurality of the interrupted main grids 126, the width of the interrupted main grid 126 in the first direction X and the width of the through line 150 in the second direction Y can be determined according to the length of the interrupted main grid 126 and the length of the through line 150. For example, when the length of the interrupted main grid 126 in the second direction Y is smaller than the length of the through line 150 in the first direction X, the width of the interrupted main grid 126 in the first direction X can be set to be smaller than the width of the through line 150 in the second direction Y; when the length of the interrupted main grid 126 in the second direction Y is greater than the length of the through line 150 in the first direction X, the width of the interrupted main grid 126 in the first direction X can be set to be greater than the width of the through line 150 in the second direction Y. The longer the length of the interrupted main grid 126 or the length of the through line 150, the more the corresponding transport path increases. According to the length of the interrupted main grid 126 and the length of the through line 150, the width of the interrupted main grid 126 and the width of the through line 150 can be determined to maintain the high carrier transport efficiency of the interrupted main grid 126 and the through line 150 while saving the cost of the paste.

[0045] When the partial number of the intermediate main grids 124 include the plurality of the interrupted main grids 126, the width of the edge main grid 123 in the first direction X can be greater than the width of the interrupted main grid 126 and smaller than the width of the remaining intermediate main grid 124. The carriers on the edge main grid 123 can be transmitted to the corresponding solder ribbon of the edge main grid 123 through the edge pad 130, and can also be transmitted to the corresponding solder ribbon of at least one intermediate main grid 124 with the same polarity through the through line 150. Therefore, the carrier transport path on the edge main grid 123 is more, and the carrier load on the edge main grid 123 is smaller compared to the intermediate main grid 124 without the interrupted main grid 126. Therefore, the width of the edge main grid 123 can be smaller than the width of the intermediate main grid 124 without the interrupted main grid 126. When the length of the edge main grid 123 is longer than the length of the interrupted main grid 126, the width of the edge main grid 123 needs to be greater than the width of the interrupted main grid 126 to meet the requirement of low resistance.

[0046] When all the intermediate busbars 124 include multiple intermittent busbars 126, each through line 150 is connected to multiple intermittent busbars 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 intermittent busbar 126 along the first direction X. That is, the through line 150 passes through the entire back contact cell along the first direction X, so that the multiple intermittent busbars 126 of the same polarity arranged along the first direction X are connected to each other, and the carrier transport path and efficiency on the fine grid 110 are improved. The length of 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 intermittent busbar 126 along the first direction X, which can reduce the internal resistance of the through line 150 itself, maintain a high carrier transport efficiency of the through line 150, and reduce the paste cost of the intermittent busbar 126.

[0047] Reference Figure 3 In some embodiments, there are two through lines 150 between the intermittent busbars 126 adjacent along the second direction Y, and the two through lines 150 are respectively connected to intermittent busbars 126 of different polarities.

[0048] Reference Figure 4 In other embodiments, there can also be only one through line 150 between the intermittent busbars 126 adjacent along the second direction Y, and the polarities of the adjacent through lines 150 along the second direction Y can be the same or different.

[0049] When all the intermediate busbars 124 include multiple intermittent busbars 126, the width of the edge busbar 123 along the first direction X is greater than the width of the intermittent busbar 126. Along the second direction Y, the length of the edge busbar 123 is longer than that of the intermediate busbar 124, and the edge busbar 123 needs to be provided with a greater width to reduce the internal resistance.

[0050] In Figures 1 to 4 In the embodiment, the edge busbar 123 is a whole root.

[0051] In other embodiments, reference Figure 5The edge main grid 123 includes first sections 1231 spaced apart from each other and second sections 1232 located on both sides of the first sections 1231 in the second direction Y, the through lines 150 are connected with the second sections 1232, the connecting lines are connected with the first sections 1231, and the fine grids 110 located at the edges of the back contact cells in the first direction X are connected with the second sections 1232 near the corners of the back contact cells, connected with the edge pads 130 near the middle of the back contact cells, or connected with the first sections 1231. In this way, the edge pads 130 are not arranged at the corner positions of the back contact cells, and the fine grids 110 at the corners are connected with other fine grids 110 of the same polarity through the second sections 1232 and the through lines 150; the fine grids 110 located at the edges of the back contact cells in the first direction X and located at the middle of the back contact cells in the second direction Y are connected with the edge pads 130 through the first sections 1231 and the connecting lines 140, or directly connected with the edge pads 130, and the carriers on the fine grids 110 at the edges of the back contact cells in the first direction X are collected through different paths, which can improve the collection efficiency of the carriers on the fine grids 110 at the edges, and can avoid arranging pads at the corners of the back contact cells to avoid the stress concentration caused by the pads at the corners to cause the fragmentation problem of the back contact cells.

[0052] When the edge main grid 123 includes the first sections 1231 and the second sections 1232, in the first direction X, the width of the first sections 1231 can be smaller than the width of the intermittent main grid 126, and / or the width of the second sections 1232 can be smaller than the width of the intermittent main grid 126. The length of the fine grid 110 connected with the first sections 1231 or the second sections 1232 is shorter than the length of the fine grid 110 connected with the intermittent main grid 126, and therefore, the width of the first sections 1231 and / or the width of the second sections 1232 can be smaller, which can be beneficial to save the use cost of the paste.

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

[0054] The back surface of the back contact battery provided in the embodiment of the present application is provided with the fine grids 110 of the first polarity and the fine grids 110 of the second polarity which are alternately arranged along the second direction Y, the fine grids 110 of the first polarity are used to collect one of the electrons or the holes in the back contact battery, the main grid 120 of the first polarity is used to collect the carriers on the fine grids 110 of the first polarity; the fine grids 110 of the second polarity are used to collect the other of the electrons or the holes in the back contact battery, the main grid 120 of the second polarity is used to collect the carriers on the fine grids 110 of the second polarity. The intermediate pad 125 is arranged on the intermediate main grid 124, and the intermediate pad 125 is used to be welded with the solder ribbon to transmit the current on the intermediate main grid 124; the edge main grid 123 is connected with the edge pad 130 through the connecting line 140, and the edge pad 130 is used to be welded with the solder ribbon 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, so that the problem of the back contact battery fragmentation caused by the excessive welding stress of the edge pad 130 which is too close to the edge of the back contact battery can be avoided, but at the same time, the distance of the carriers on the edge main grid 123 is increased, and the transmission efficiency is reduced; therefore, the edge main grid 123 on the back contact battery provided in the embodiment of the present application is further connected with at least one intermediate main grid 124 which has the same polarity as the edge main grid 123 through the penetrating line 150, so that the carriers on the edge main grid 123 can be transmitted to the solder ribbon corresponding to the edge main grid 123 through the edge pad 130, and can also be transmitted to at least one intermediate main grid 124 which has the same polarity as the edge main grid 123 through the penetrating line 150, and then transmitted to the solder ribbon through the intermediate main grid 124, so as to improve the carrier transmission efficiency of the edge main grid 123. Since the penetrating line 150 and the connecting line 140 are both connected with the edge main grid 123, the carriers of the plurality of fine grids 110 are collected on the edge main grid 123, and the width of the penetrating line 150 and the width of the connecting line 140 are both greater than the width of the fine grid 110, which is beneficial to reduce the internal resistance of the penetrating line 150 and the connecting line 140, and further improve the carrier transmission efficiency. In addition, since the length of the penetrating line 150 is longer than the length of the connecting line 140, the carrier transmission path is longer, and the width of the penetrating line 150 is greater than the width of the connecting line 140, which is beneficial to improve the transmission efficiency of the carriers in the penetrating line 150.

[0055] Correspondingly, another embodiment of the present application further provides a photovoltaic module, which comprises: a plurality of back contact batteries, a solder ribbon, a film and a cover plate, the solder ribbon is connected with the intermediate pad or the edge pad of the adjacent back contact battery; the film covers the surface of the back contact battery; and the cover plate is located on the surface of the film away from the back contact battery. The same or corresponding parts of the above embodiment can be referred to the corresponding description of the foregoing embodiment, and will not be described in detail hereinafter.

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

[0057] The cover plate can be a glass cover plate, a plastic cover plate, or the like having 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 incident light.

[0058] It can be understood by those skilled in the art that the above-mentioned embodiments are specific embodiments for implementing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. A back contact cell, characterized in that, On the back of the back contact cell, comprising: a plurality of fine grids, the fine grids extending along a first direction, and the fine grids of different polarities being arranged alternately along a second direction; a plurality of main grids, the main grids extending along the second direction, and the main grids of different polarities being arranged alternately along the first direction, each of the main grids being electrically connected with a plurality of fine grids of the same polarity arranged along the second direction, wherein the main grids located at the edges of the back contact cell 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, the width of the intermediate pads being greater than the width of the intermediate main grid along the first direction, and at least the intermediate main grids adjacent to the edge main grids comprising a plurality of spaced apart discontinuous main grids, each of the discontinuous main grids having at least one intermediate pad thereon; edge pads, the edge pads being located at the edges of the back contact cell along the first direction, the distance between the edge pads and the edge of the back contact cell being greater than the distance between the edge main grids and the edge of the back contact cell; connection lines, the connection lines extending along the first direction, and the two ends of the connection lines being connected with the edge pads and the edge main grids, respectively; through lines, the through lines extending along the first direction, and the through lines connecting the edge main grids and at least one intermediate main grid of the same polarity as the edge main grids, the discontinuous main grids being located on both sides of the through lines along the second direction; along the second direction, the width of the connection lines and the width of the through lines are both greater than the width of the fine grids, and the width of the through lines is greater than the width of the connection lines.

2. The back contact cell of claim 1, wherein, along the second direction, the total number of the edge pads is less than the number of the intermediate pads corresponding to any intermediate main grid.

3. The back contact cell of claim 1, wherein, A part of the intermediate main grids comprise a plurality of discontinuous main grids, and along the first direction, the width of the discontinuous main grids is less than the width of the remaining intermediate main grids.

4. The back contact cell of claim 3, wherein, The length of the discontinuous main grids along the second direction is less than the length of the through lines along the first direction, and the width of the discontinuous main grids along the first direction is less than the width of the through lines along the second direction.

5. The back contact cell of claim 3, wherein, along the first direction, the width of the edge main grids is greater than the width of the discontinuous main grids, and less than the width of the remaining intermediate main grids.

6. The back contact cell of claim 1, wherein, All the intermediate main grids comprise a plurality of discontinuous main grids, each of the through lines connecting a plurality of discontinuous main grids of the same polarity arranged along the first direction, and the width of the through lines along the second direction is greater than the width of the discontinuous main grids along the first direction.

7. The back contact cell of claim 6, wherein, between the adjacent discontinuous main grids along the second direction, there are two through lines, and the two through lines are connected with the discontinuous main grids of different polarities, respectively.

8. The back contact cell of claim 6, wherein, along the first direction, the width of the edge main grids is greater than the width of the discontinuous main grids.

9. The back contact cell of claim 1, wherein, The edge main grid comprises first parts spaced from each other and second parts located on both sides of the first parts in the second direction, the through lines are connected with the first parts, the connection lines are connected with the second parts, the fine grids located at edges of the back contact cells in the first direction are connected with the second parts, the fine grids close to corners of the back contact cells are connected with the second parts, and the fine grids close to the middle of the back contact cells are connected with the edge pads or the first parts.

10. A photovoltaic module, characterized by, Comprise: a plurality of back contact cells as claimed in any one of claims 1-9; a solder strip connecting pads or edge pads of adjacent back contact cells; an adhesive film covering surfaces of the back contact cells; a cover plate located on a surface of the adhesive film away from the back contact cells.

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