Back contact cell, back contact cell string and back contact photovoltaic module

Abstract

The invention relates to a back contact cell, a back contact cell string and a back contact photovoltaic module. The back contact battery comprises a battery piece; the first pole main grid is used for being electrically connected with a first conductive connecting piece of the back contact battery string; a plurality of first fine grids; the second pole main grid is used for being electrically connected to a second conductive connecting piece of the back contact battery string; and a plurality of second fine grids; the first superfine grid is disconnected at the second pole main grid to form a first disconnected area, the second superfine grid is disconnected at the first pole main grid to form a second disconnected area, the first conductive connecting piece is arranged in the second disconnected area and has a preset distance with the second superfine grid, and the second conductive connecting piece is arranged in the first disconnected area and has a preset distance with the second superfine grid. And a preset distance exists between the first fine grid and the first fine grid. Therefore, the first ultra-fine grid is not electrically connected to the second pole main grid, and the second ultra-fine grid is not electrically connected to the first pole main grid, so that the problem of short circuit caused by lack of glue or piercing of insulating glue by a welding strip barb is avoided, and the use performance of the back contact battery is ensured.

Description

TECHNICAL FIELD

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

[0002] The metal electrode design of the back contact cell (IBC cell) is on the back of the cell sheet, and the front of the cell sheet is not blocked by any grid line. In this way, the back contact cell has a larger light absorption area and higher cell efficiency.

[0003] Currently, in the mainstream SMBB (Super Multi-Busbar, super multi-main grid technology) cell sheet, the cell sheet edge has 2 main grids. When the back contact photovoltaic module string is welded, two back contact cells are interconnected by a welding strip, and the welding strip is welded on the PAD point of the back contact cell sheet. The positive and negative electrode fine grids are located below the welding strip.

[0004] Generally, the fine grids of the positive and negative electrodes exist below the welding strip, and the short circuit risk is high, which affects the use performance of the back contact photovoltaic module. Therefore, a layer of insulating glue is coated between the welding strip and the fine grid line of the opposite electrode to block the welding strip and the fine grid line, so as to avoid short circuit caused by the contact between the welding strip and the fine grid line of the opposite electrode.

[0005] Currently, the back contact module uses epoxy resin type insulating glue, which is mainly covered on the fine grid line of the opposite electrode above the welding strip by means of screen printing. However, if the insulating glue printing is missing or the burr generated by the welding strip cutting, the welding strip will still be overlapped with the fine grid line of the opposite electrode below, which will cause short circuit. SUMMARY

[0006] Therefore, it is necessary to provide a back contact cell, a back contact cell string and a back contact photovoltaic module to avoid the short circuit problem caused by the missing or damaged glue and the insulating glue pierced by the burr of the welding strip, and to ensure the use performance of the back contact cell.

[0007] A back contact cell, comprising:

[0008] a cell sheet;

[0009] a first electrode main grid arranged on the back of the cell sheet and used for electrically connecting a first conductive connecting piece of a back contact cell string;

[0010] a plurality of first electrode fine grids arranged on the back of the cell sheet in parallel and at intervals in a first direction and extending in a second direction, and each of the plurality of first electrode fine grids is electrically connected to the first electrode main grid;

[0011] a second main grid disposed on the back surface of the cell sheet and configured to electrically connect to a second conductive connector of the back contact cell string; and

[0012] a plurality of second fine grids disposed on the back surface of the cell sheet in parallel and at intervals along a first direction and extending along a second direction, each of the plurality of second fine grids being electrically connected to the second main grid;

[0013] wherein the plurality of first fine grids and the plurality of second fine grids are alternately distributed along an extension direction of the first main grid, the first fine grids are broken at the second main grid to form a first broken area, the second fine grids are broken at the first main grid to form a second broken area, the first conductive connector is disposed in the second broken area and has a preset interval with the second fine grids, and the second conductive connector is disposed in the first broken area and has a preset interval with the first fine grids.

[0014] In an embodiment of the present application, each of the first fine grids comprises a plurality of first fine grid lines and a plurality of second fine grid lines, the plurality of first fine grid lines and the plurality of second fine grid lines are alternately distributed along the second direction, and adjacent first fine grid lines and second fine grid lines are located on two sides of the second main grid with a preset interval therebetween to form the first broken area.

[0015] and / or, each of the second fine grids comprises a plurality of third fine grid lines and a plurality of fourth fine grid lines, the plurality of third fine grid lines and the plurality of fourth fine grid lines are alternately distributed along the second direction, and adjacent third fine grid lines and fourth fine grid lines are located on two sides of the first main grid with a preset interval therebetween to form the second broken area.

[0016] In an embodiment of the present application, the first broken area is symmetrically disposed relative to the second main grid.

[0017] and / or, the second broken area is symmetrically disposed relative to the first main grid.

[0018] and / or, a size of the first broken area along the second direction ranges from 1.2 mm to 1.6 mm.

[0019] and / or, a size of the second broken area along the second direction ranges from 1.2 mm to 1.6 mm.

[0020] In an embodiment of the present application, the first pole main grid comprises a first main grid line, a second main grid line and a third main grid line, the first main grid line is arranged at the inner side of the cell sheet, the second main grid line and the third main grid line are arranged at the edge of the cell sheet, the first main grid line and the third main grid line extend along a first direction, the second main grid line extends along a second direction and electrically connects the first main grid line and the third main grid line, and the first conductive connecting piece is arranged on the first main grid line.

[0021] And / or, the second pole main grid comprises a first grid line, a second grid line and a third grid line, the first grid line and the second grid line are arranged at the inner side of the cell sheet, the third grid line is arranged at the edge of the cell sheet, the first grid line and the third grid line extend along a first direction, the second grid line extends along a second direction and electrically connects the first grid line and the third grid line.

[0022] In an embodiment of the present application, the third main grid line is collinear with the third grid line, and a set interval exists between the third main grid line and the third grid line, and the size of the set interval ranges from 1mm to 1.6mm.

[0023] And / or, a predetermined interval exists between the first grid line and the second main grid line.

[0024] And / or, the size of the first grid line along the first direction ranges from 2.5mm to 5.75mm.

[0025] In an embodiment of the present application, the back contact cell further comprises a first pole pad, the first pole pad is arranged on the back surface of the cell sheet and electrically connected with the first pole main grid.

[0026] The back contact cell further comprises a second pole pad, the second pole pad is arranged on the back surface of the cell sheet and electrically connected with the second pole main grid.

[0027] In an embodiment of the present application, the back contact cell further comprises a plurality of insulation parts, the plurality of insulation parts are respectively arranged at the end of the first pole main grid located at the first disconnection area, and / or the plurality of insulation parts are respectively arranged at the end of the second pole fine grid located at the second disconnection area.

[0028] A back contact cell string comprises a first conductive connecting piece, a second conductive connecting piece and a plurality of back contact cells as any one of the technical features described above.

[0029] The first conductive connecting piece is electrically connected with the first pole main grid of two adjacent back contact cells and is located at the second disconnection area of the back contact cell, and the second conductive connecting piece is electrically connected with the second pole main grid of the back contact cell and is located at the first disconnection area of the back contact cell.

[0030] In an embodiment of the present application, the distance between the first conductive connecting piece and the second fine grid of the back contact cell ranges from 0.3mm to 0.5mm;

[0031] And / or, the distance between the second conductive connecting piece and the first fine grid of the back contact cell ranges from 0.3mm to 0.5mm.

[0032] A back contact photovoltaic module comprising a cover plate, a back plate and a plurality of back contact cell strings as described in any of the technical features above;

[0033] The cover plate and the back plate are arranged on both sides of the back contact cell string, and the cover plate, the back plate and the back contact cell string are encapsulated by an encapsulation process.

[0034] After adopting the technical solution described above, the present application has at least the following technical effects:

[0035] The back contact cell, the back contact cell string and the back contact photovoltaic module of the present application, in the back contact cell, the first fine grid is disconnected at the second main grid to form a first disconnected area, so that the first fine grid is not electrically connected to the second main grid, and the second fine grid is disconnected at the first main grid to form a second disconnected area, so that the second fine grid is not electrically connected to the first main grid. After the first main grid is electrically connected to the first conductive connecting piece and the second main grid is electrically connected to the second conductive connecting piece, the first conductive connecting piece is only electrically connected to the corresponding first fine grid, and the second conductive connecting piece is only electrically connected to the second fine grid.

[0036] In this way, the first conductive connecting piece is only electrically connected to the first fine grid and does not cross the second fine grid, so as not to be electrically connected to the first fine grid, and the second conductive connecting piece is only electrically connected to the second fine grid and does not cross the first fine grid, so as not to be electrically connected to the second fine grid. In this way, the short circuit problem caused by the absence of glue or the puncture of insulating glue by the solder strip barb can be avoided, and the use performance of the back contact cell is ensured. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 It is a schematic diagram of the back contact cell of an embodiment of the present application.

[0038] Figure 2 It is a schematic diagram of the back contact cell connected with the first conductive connecting piece and the second conductive connecting piece. Figure 1

[0039] Figure 3 It is a schematic diagram of the back contact cell connected with the first conductive connecting piece and the second conductive connecting piece. Figure 2

[0040] Figure 4 It is a schematic diagram of the back contact cell connected with the first conductive connecting piece and the second conductive connecting piece.​​Figure 1 A partial enlarged view of the back contact cell shown at A.

[0041] Figure 5 For Figure 2 A partial enlarged view of the back contact cell shown at B.

[0042] Wherein: 10, back contact cell string; 100, back contact cell; 110, cell piece; 120, first pole main grid; 121, first main grid line; 122, second main grid line; 123, third main grid line; 130, first pole fine grid; 131, first disconnection area; 132, first fine grid line; 133, second fine grid line; 140, second pole main grid; 141, first grid line; 142, second grid line; 143, third grid line; 150, second pole fine grid; 151, second disconnection area; 152, third fine grid line; 153, fourth fine grid line; 160, first pole pad; 170, second pole pad; 180, insulation part; 200, first conductive connecting piece; 300, second conductive connecting piece. DETAILED DESCRIPTION

[0043] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be practiced in a variety of ways beyond the specific embodiments described herein, and skilled persons in the art can make similar improvements without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0044] In the description of the present application, if the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like appear, these terms indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0045] In addition, the terms "first", "second", and the like, if any, are used herein for descriptive purposes only and should not be construed as indicating or implying relative importance or implicating the number of indicated technical features. Thus, a feature defined with "first", "second" may explicitly or implicitly include at least one of the features. In the description of the present application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0046] In the present application, unless otherwise explicitly specified and limited, if the terms "mounting", "connecting", "connecting", "fixing" and the like appear, these terms should be interpreted broadly. For example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0047] In the present application, unless otherwise explicitly specified and limited, if the first feature is described as "on" or "under" the second feature, etc., it can mean that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the second feature, or it can only mean that the first feature is higher than the second feature in horizontal height. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the second feature, or it can only mean that the first feature is lower than the second feature in horizontal height.

[0048] It should be noted that if an element is referred to as "fixed to" or "disposed to" another element, it can be directly on another element or there can be a middle element. If an element is considered to be "connected" to another element, it can be directly connected to another element or there can be a middle element. If present, the terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used in the present application are only for illustrative purposes and do not represent the only implementation.

[0049] It can be understood that the metal electrode design of the interdigitated back contact (IBC cell) is on the back of the cell sheet, and the front of the cell sheet is not blocked by any grid line. When the back contact photovoltaic module string is welded, two back contact cells are interconnected by a welding strip, the welding strip is welded on the PAD point of the back contact cell sheet, and the positive and negative electrode fine grid is located below the welding strip. Usually, a layer of insulating glue is coated between the welding strip and the fine grid line of the opposite electrode to block the welding strip and the fine grid line, so as to avoid short circuit caused by the contact between the welding strip and the fine grid of the opposite electrode.

[0050] At present, the back contact module uses epoxy resin insulating glue, which is mainly coated on the fine grid line of the opposite electrode of the welding strip by screen printing. However, if the insulating glue printing is missing or the burr generated by the welding strip cutting, the welding strip will also be overlapped with the fine grid line of the opposite electrode below, which will also cause short circuit.

[0051] Therefore, referring to Figure 1 and Figure 2 , the present application provides a novel back contact cell 100. The back contact cell 100 is applied to the back contact cell string 10 of the back contact photovoltaic module (not shown). Figure 1 The schematic diagram of the back contact cell 100 according to an embodiment of the present application is shown in Figure 2 The schematic diagram of the back contact cell 100 shown in Figure 1 connected with the first conductive connecting piece 200 and the second conductive connecting piece 300 is shown in Figure 3 The schematic diagram of the back contact cell string 10 prepared by using the back contact cell 100 shown in Figure 2

[0052] The back contact cell 100 of the present application can electrically connect the conductive connecting piece with the fine grid of the same polarity, and not electrically connect with the fine grid of the opposite polarity, thereby avoiding the short circuit problem caused by the missing glue or the burr of the welding strip piercing the insulating glue, and ensuring the use performance of the back contact cell 100.

[0053] To better illustrate the structure of the back contact cell 100, the structure of the back contact cell string 10 is first introduced. As shown in Figures 1 to 3 The back contact cell string 10 includes the first conductive connecting piece 200, the second conductive connecting piece 300 and at least two back contact cells 100 of the present application. In Figure 3 , only the first conductive connecting piece 200 and the second conductive connecting piece 300 are shown to connect two back contact cells 100 in series.

[0054] ​One end of the first conductive connecting piece 200 is electrically connected to the previous back contact cell 100, and the other end is electrically connected to the next back contact cell 100. One end of the second conductive connecting piece 300 is electrically connected to the previous back contact cell 100, and the other end is electrically connected to the next back contact cell 100. When the back contact cell 100 is three or more, the connection form is substantially the same as that of the back contact cell 100 being two, which will not be described again hereinafter.

[0055] The specific structure of the back contact cell 100 of an embodiment will be described below.

[0056] Referring to Figures 1 to 5 In an embodiment, the back contact cell 100 includes a cell sheet 110, a first pole main grid 120, a plurality of first pole fine grids 130, a second pole main grid 140, and a plurality of second pole fine grids 150. The first pole main grid 120 is arranged on the back surface of the cell sheet 110 and is used for electrically connecting the first conductive connecting piece 200 of the back contact cell string 10. The plurality of first pole fine grids 130 are arranged in parallel and at intervals along a first direction on the back surface of the cell sheet 110 and extend along a second direction. The plurality of first pole fine grids 130 are respectively electrically connected to the first pole main grid 120.

[0057] The second pole main grid 140 is arranged on the back surface of the cell sheet 110 and is used for electrically connecting the second conductive connecting piece 300 of the back contact cell string 10. The plurality of second pole fine grids 150 are arranged in parallel and at intervals along the first direction on the back surface of the cell sheet 110 and extend along the second direction. The plurality of second pole fine grids 150 are respectively electrically connected to the second pole main grid 140. Among them, the plurality of first pole fine grids 130 and the plurality of second pole fine grids 150 are alternately distributed along the extension direction of the first pole main grid 120.

[0058] The first pole fine grid 130 is broken at the second pole main grid 140 to form a first broken area 131, and the second pole fine grid 150 is broken at the first pole main grid 120 to form a second broken area 151. The first conductive connecting piece 200 is arranged in the second broken area 151 and has a preset interval with the second pole fine grid 150. The second conductive connecting piece 300 is arranged in the first broken area 131 and has a preset interval with the first pole fine grid 130. Figure 4 For Figure 1 The partial enlarged view of the back contact cell 100 at A shown in the figure, Figure 5 For Figure 2 The partial enlarged view of the back contact cell 100 at B shown in the figure.

[0059] The cell sheet 110 extends along the first direction and the second direction. The first direction and the second direction are as shown in Figures 2 to 5As shown, the first direction is perpendicular to the second direction, the first direction is the length direction of the battery piece 110, and the second direction is the width direction of the battery piece 110. The battery piece 110 has a certain length dimension along the first direction and a certain width dimension along the second direction.

[0060] The battery piece 110 is made of a silicon wafer. The battery piece 110 is used to absorb solar energy and convert the solar energy into electrical energy. The specific structure and principle of the battery piece 110 are prior art, and will not be described here. The surface of the battery piece 110 that absorbs sunlight is the front surface of the battery piece 110, i.e., the light-receiving surface of the battery piece 110. The surface of the battery piece 110 that faces away from the sunlight is the back surface of the battery piece 110, i.e., the back light surface of the battery piece 110.

[0061] In the back contact battery 100 of the present application, the first main grid 120, the second main grid 140, the first fine grid 130, and the second fine grid 150 are all arranged on the back surface of the battery piece 110. In this way, the first main grid 120, the second main grid 140, the first fine grid 130, and the second fine grid 150 do not block the front surface of the battery piece 110, thereby increasing the light-receiving area of the battery piece 110 and improving the conversion efficiency of the battery piece 110.

[0062] It can be understood that the polarities of the first main grid 120 and the second main grid 140 are different, the polarities of the first fine grid 130 and the second fine grid 150 are different, the polarities of the first main grid 120 and the first fine grid 130 are the same, and the polarities of the second main grid 140 and the second fine grid 150 are the same.

[0063] In the present embodiment, the first main grid 120 is a positive main grid, the first fine grid 130 is a positive fine grid, the second main grid 140 is a negative main grid, and the second fine grid 150 is a negative fine grid. Of course, in other embodiments of the present application, the first main grid 120 can be a negative main grid, the first fine grid 130 can be a negative fine grid, the second main grid 140 can be a positive main grid, and the second fine grid 150 can be a positive fine grid.

[0064] Hereinafter, when describing the structure of the back contact battery 100, the first main grid 120 is used instead of the positive main grid, the first fine grid 130 is used instead of the positive fine grid, the second main grid 140 is used instead of the negative main grid, and the second fine grid 150 is used instead of the negative fine grid.

[0065] The first fine grid 130 extends along the second direction, and a plurality of first fine grids 130 are arranged in parallel and at intervals along the first direction. The second fine grid 150 extends along the second direction, and a plurality of second fine grids 150 are arranged in parallel and at intervals along the first direction.

[0066] And, the plurality of first fine grids 130 and the plurality of second fine grids 150 are also alternately distributed along the first direction. That is, one second fine grid 150 is arranged between two adjacent first fine grids 130, and one first fine grid 130 is arranged between two adjacent second fine grids 150.

[0067] The plurality of first fine grids 130 are respectively electrically connected with the first main grid 120, and the plurality of second fine grids 150 are respectively electrically connected with the second main grid 140. The first conductive connecting member 200 of the back contact cell string 10 is arranged on the first main grid 120 along the first direction and is electrically connected with the first main grid 120, and the second conductive connecting member 300 in the back contact cell string 10 is arranged on the second main grid 140 along the second direction and is electrically connected with the second main grid 140.

[0068] The first fine grid 130 can collect the current generated by the photo-generated carriers of the cell sheet 110, and the first main grid 120 can collect the current collected by each first fine grid 130. The second fine grid 150 can collect the current generated by the photo-generated carriers of the cell sheet 110, and the second main grid 140 can collect the current collected by each second fine grid 150. The photo-generated carriers of the cell sheet 110 flow along the first fine grid 130 to the first main grid 120, and then flow to the first conductive connecting member 200 through the first main grid 120, forming a current collection path.

[0069] It can be understood that, due to the alternate arrangement of the first fine grid 130 and the second fine grid 150 along the first direction, the first conductive connecting member 200 and the second fine grid 150 are likely to have conductive contact, and the second conductive connecting member 300 and the first fine grid 130 are likely to have conductive contact. Therefore, the present application sets a first disconnection area 131 at the position corresponding to the second main grid 140 of the first fine grid 130, and sets a second disconnection area 151 at the position corresponding to the first main grid 120 of the second fine grid 150.

[0070] The first fine grid 130 is disconnected at the position corresponding to the second main grid 140, and the disconnected area is the second disconnection area 151. The first fine grid 130 is divided into two parts, which are respectively located on the two sides of the second main grid 140. That is, at the position where the first fine grid 130 intersects with the second main grid 140, a length of the first fine grid is removed, and the removed length area is the first disconnection area 131. In this way, the first fine grid 130 and the second main grid 140 gradually have no intersection part.

[0071] The second fine grid 150 is provided with a second disconnection area 151 at the position corresponding to the first main grid 120. The second fine grid 150 is divided into two parts, which are located on the two sides of the first main grid 120. That is, a length of the first fine grid 130 is removed at the position where the second fine grid 150 intersects with the first main grid 120, and the removed length forms the second disconnection area 151. In this way, the first fine grid 130 and the second main grid 140 gradually have no intersection.

[0072] In this way, after the first fine grid 130 is provided with the second disconnection area 151 at the second main grid 140, the first fine grid 130 and the second main grid 140 have a preset interval, and the first fine grid 130 is only electrically connected to the first main grid 120 and is not electrically connected to the second main grid 140. The second fine grid 150 is disconnected at the first main grid 120 to form the second disconnection area 151, and the second fine grid 150 is only electrically connected to the second main grid 140 and is not electrically connected to the first main grid 120.

[0073] When the first conductive connector 200 is arranged along the first direction on the first main grid 120, the first conductive connector 200 does not contact the second fine grid 150, and the problem of short circuit caused by the second conductive connector 300 being in conduction with the second fine grid 150 does not occur. When the second conductive connector 300 is arranged along the first direction on the second main grid 140, the second conductive connector 300 does not contact the first fine grid 130, and the problem of short circuit caused by the second conductive connector 300 being in conduction with the first fine grid 130 does not occur.

[0074] In this way, even if the first fine grid 130 is not covered with insulating glue or the first conductive connector 200 pierces the insulating glue, the second conductive connector 300 will not be electrically connected to the first fine grid 130. Even if the second fine grid 150 is not covered with insulating glue or the second conductive connector 300 pierces the insulating glue, the first conductive connector 200 will not be electrically connected to the second fine grid 150. The problem of short circuit between the first conductive connector 200 and the second fine grid 150 is avoided, and the problem of short circuit between the second conductive connector 300 and the first fine grid 130 is avoided.

[0075] That is, the conductive connector does not cross the fine grid with opposite polarity, and the conductive connector is only electrically connected to the fine grid with the same polarity and is not electrically connected to the fine grid with opposite polarity. In this way, even if the fine grid with opposite polarity of the conductive connector is not covered with insulating glue or the conductive connector pierces the insulating glue, the conductive connector will not be in electrical contact with the fine grid with opposite polarity, and the problem of short circuit will not occur, thereby ensuring the use performance of the back contact battery 100.

[0076] The back contact battery 100 of the above embodiment forms a first disconnection area 131 by disconnecting the first fine grid 130 at the second main grid 140, so that the first fine grid 130 is not electrically connected to the second main grid 140, and forms a second disconnection area 151 by disconnecting the second fine grid 150 at the first main grid 120, so that the second fine grid 150 is not electrically connected to the first main grid 120. In this way, the short circuit problem caused by the absence of glue or the puncture of insulating glue by solder strip barbs can be avoided, and the use performance of the back contact battery 100 can be ensured.

[0077] It should be noted that, Figure 4 and Figure 5 are partial views of the corner of the back contact battery 100. Generally, the back contact battery 100 is prone to short circuit at the corner. The present application optimizes the corner of the back contact battery 100 to avoid short circuit at the corner of the back contact battery 100 and improve the durability of the back contact battery 100.

[0078] Moreover, Figure 4 and Figure 5 are the corners of the back contact battery 100 shown in Figure 2 and Figure 3 are parts of the back contact battery 100 shown in

[0079] The structure and design principle of other parts of the back contact battery 100 are substantially the same as those of the corner of the back contact battery 100 shown in Figure 4 and Figure 5 The structure and design principle of other parts of the back contact battery 100 are substantially the same as those of the corner of the back contact battery 100 shown in Figure 4 and Figure 5 The structure and design principle of other parts of the back contact battery 100 are substantially the same as those of the corner of the back contact battery 100 shown in

[0080] In an embodiment, the first conductive connecting member 200 is a solder strip, and the second conductive connecting member 300 is a solder strip. That is, two adjacent back contact batteries 100 are connected in series by at least two solder strips to form a back contact battery string 10. Of course, in other embodiments of the present application, the first conductive connecting member 200 and the second conductive connecting member 300 can also be conductive wires or other components capable of realizing current collection.

[0081] Referring to Figure 4 and Figure 5In an embodiment, each first fine grid 130 includes a plurality of first fine grid lines 132 and a plurality of second fine grid lines 133, the plurality of first fine grid lines 132 and the plurality of second fine grid lines 133 are alternately arranged along the second direction, and adjacent first fine grid lines 132 and second fine grid lines 133 are located on both sides of the second main grid 140 with a predetermined spacing therebetween to form the first disconnection area 131.

[0082] The first fine grid 130 is disconnected at the second main grid 140 to avoid the possibility of electrical connection between the second main grid 140 and the first fine grid 130. For ease of description, the plurality of fine grid lines formed after the first fine grid 130 is disconnected are denoted as a plurality of first fine grid lines 132 and a plurality of second fine grid lines 133 arranged at intervals along the second direction.

[0083] The first fine grid 130 extends along the second direction, and the first fine grid 130 includes a plurality of first fine grid lines 132 and a plurality of second fine grid lines 133, the plurality of first fine grid lines 132 and the plurality of second fine grid lines 133 are alternately and spaced arranged along the plurality of second directions. As shown in Figure 4 and Figure 5 The left fine grid line is the first fine grid line 132, and the right fine grid line is the second fine grid line 133.

[0084] And, there is a certain spacing between adjacent first fine grid lines 132 and second fine grid lines 133, which is the first disconnection area 131. The second main grid 140 is arranged in the first disconnection area 131 along the first direction, and there is a predetermined spacing between the second main grid 140 and the first fine grid line 132, and there is also a predetermined spacing between the second main grid 140 and the second fine grid line 133.

[0085] In this way, the second main grid 140 does not intersect with the first fine grid line 132 and the second fine grid line 133, and after the second conductive connecting piece 300 is arranged behind the second main grid 140 along the first direction, the second conductive connecting piece 300 does not have conductive connection with the first fine grid line 132 and the second fine grid line 133, thereby avoiding the occurrence of short circuit.

[0086] At the same time, the first fine grid line 132 and the second fine grid line 133 are also electrically connected to the first main grid 120. In this way, the first fine grid line 132 and the second fine grid line 133 can transmit the current of the battery piece 110 to the first main grid 120, and transmit the current to the first conductive connecting piece 200 through the first main grid 120, realizing the output of the current.

[0087] And, in Figure 4 and Figure 5In the embodiment, only one first fine grid 130 is shown, which includes one first fine grid line 132 and one second fine grid line 133. In practice, the number of first fine grid lines 132 and the number of second fine grid lines 133 are both at least two, and the at least two first fine grid lines 132 and the at least two second fine grid lines 133 are arranged alternately along the second direction.

[0088] That is, one second fine grid line 133 is arranged between two adjacent first fine grid lines 132, and one first fine grid line 132 is arranged between two adjacent second fine grid lines 133. In addition, the length of the first fine grid line 132 along the second direction is less than the length of the second fine grid line 133 along the second direction.

[0089] The structure and working principle of the first fine grid line 132 and the second fine grid line 133 are substantially the same, and the lengths of the first fine grid line 132 and the second fine grid line 133 can be different. Of course, the lengths of the first fine grid lines 132 can be different or the same, and the lengths of the second fine grid lines 133 can be different or the same.

[0090] In this way, the first fine grid 130 is arranged to be disconnected to form the first fine grid line 132 and the second fine grid line 133 arranged alternately along the second direction, and the second main grid 140 is located in the first disconnected area 131 formed by the first fine grid line 132 and the second fine grid line 133, so as to avoid the electrically conductive connection between the second main grid 140 and the first fine grid line 132 and the second fine grid line 133, thereby avoiding the short circuit. At the same time, the first fine grid line 132 and the second fine grid line 133 are electrically connected to the first main grid 120, so as to realize the collection of the current.

[0091] Referring to Figure 4 and Figure 5 In an embodiment, each second fine grid 150 includes a plurality of third fine grid lines 152 and a plurality of fourth fine grid lines 153, the plurality of third fine grid lines 152 and the plurality of fourth fine grid lines 153 are arranged alternately along the second direction, and adjacent third fine grid lines 152 and fourth fine grid lines 153 are located on both sides of the first main grid 120 with a predetermined distance therebetween to form a second disconnected area 151.

[0092] The application disconnects the second fine grid 150 at the first main grid 120 to avoid the possibility of electrical connection between the first main grid 120 and the second fine grid 150. For the convenience of description, the plurality of fine grid lines formed after the second fine grid 150 is disconnected are recorded as a plurality of third fine grid lines 152 and a plurality of fourth fine grid lines 153 arranged at intervals along the second direction.

[0093] The second fine grid 150 extends along the second direction, and the second fine grid 150 includes a plurality of third fine grid lines 152 and a plurality of fourth fine grid lines 153, the third fine grid lines 152 and the fourth fine grid lines 153 are arranged alternately and at intervals along the second direction. As shown in FIG. 2, the third fine grid line 152 and the fourth fine grid line 153 are arranged alternately along the second direction, and the length of the third fine grid line 152 along the second direction is less than the length of the fourth fine grid line 153 along the second direction.Figure 4 and Figure 5 As shown in FIG. 1, the left fine grid line is the third fine grid line 152, and the right fine grid line is the fourth fine grid line 153.

[0094] Further, there is a certain spacing between the adjacent third fine grid line 152 and the fourth fine grid line 153, which is the second disconnection area 151. The first pole main grid 120 is arranged in the second disconnection area 151 along the first direction, and there is a preset spacing between the first pole main grid 120 and the third fine grid line 152, and there is also a preset spacing between the first pole main grid 120 and the fourth fine grid line 153.

[0095] In this way, the first pole main grid 120 does not intersect with the third fine grid line 152 and the fourth fine grid line 153, and after the second conductive connecting piece 300 is arranged behind the first pole main grid 120 along the first direction, the second conductive connecting piece 300 will not be in conductive connection with the third fine grid line 152 and the fourth fine grid line 153, thereby avoiding the occurrence of short circuit.

[0096] Meanwhile, the third fine grid line 152 and the fourth fine grid line 153 are also electrically connected to the second pole main grid 140. In this way, the third fine grid line 152 and the fourth fine grid line 153 can transmit the current of the battery piece 110 to the second pole main grid 140, and transmit the current to the second conductive connecting piece 300 through the second pole main grid 140, thereby realizing the output of the current.

[0097] Further, in Figure 4 and Figure 5 only one second pole fine grid 150 is shown to include one third fine grid line 152 and one fourth fine grid line 153. In fact, the number of third fine grid lines 152 and the number of fourth fine grid lines 153 are both at least two, and the at least two third fine grid lines 152 and the at least two fourth fine grid lines 153 are arranged alternately along the second direction.

[0098] That is, one fourth fine grid line 153 is arranged between two adjacent third fine grid lines 152, and one third fine grid line 152 is arranged between two adjacent fourth fine grid lines 153. Further, the length of the third fine grid line 152 along the second direction is greater than the length of the fourth fine grid line 153 along the second direction.

[0099] The structure and working principle of the third fine grid line 152 and the fourth fine grid line 153 are substantially the same, and the lengths of the third fine grid line 152 and the fourth fine grid line 153 can be different. Of course, the lengths of the various third fine grid lines 152 can be different or the same, and the lengths of the various fourth fine grid lines 153 can be different or the same.

[0100] Thus, the second fine grid 150 is disconnected to form third fine grid lines 152 and fourth fine grid lines 153 arranged alternately along the second direction, and the first main grid 120 is located in the second disconnected area 151 formed by the third fine grid lines 152 and the fourth fine grid lines 153 to avoid the electrically conductive connection between the first main grid 120 and the third fine grid lines 152 and the fourth fine grid lines 153, thereby avoiding the short circuit, and meanwhile, the third fine grid lines 152 and the fourth fine grid lines 153 are electrically connected to the second main grid 140 to realize the current collection.

[0101] Of course, in other embodiments of the present application, the second fine grid 150 can further include a fifth fine grid line extending along the first direction, the fifth fine grid line being connected to the third fine grid line 152 or the fourth fine grid line 153 at the edge of the second fine grid 150, and the fifth fine grid line being further connected to the second main grid 140.

[0102] Referring to Figure 4 and Figure 5 In an embodiment, the first disconnected area 131 is symmetrically arranged relative to the second main grid 140. That is, the second main grid 140 is located in the middle region of the first disconnected area 131, and the distance between the second main grid 140 and the first fine grid line 132 is equal to the distance between the second main grid 140 and the second fine grid line 133.

[0103] In this way, the distance between the second main grid 140 and the first fine grid lines 130 on both sides is equal, and when the second electrically conductive connector 300 is arranged behind the second main grid 140, the distance between the second electrically conductive connector 300 and the first fine grid lines 130 on both sides is substantially equal, so that even if the second electrically conductive connector 300 has a certain deviation during installation, the second electrically conductive connector 300 can avoid electrically contacting the first fine grid line 130 on one side, thereby avoiding the short circuit.

[0104] Referring to Figure 4 and Figure 5 In an embodiment, the size of the first disconnected area 131 along the second direction ranges from 1.2 mm to 1.6 mm. That is, the distance between the end of the first fine grid line 132 and the end of the adjacent second fine grid line 133 ranges from 1.2 mm to 1.6 mm.

[0105] After the second main grid 140 is arranged in the first disconnected area 131, the distance between the second main grid 140 and the first fine grid line 132 ranges from 0.6 mm to 0.8 mm, and the distance between the second main grid 140 and the second fine grid line 133 ranges from 0.6 mm to 0.8 mm, thereby avoiding the intersection between the second main grid 140 and the first fine grid line 130.

[0106] It can be understood that the width dimension of the second conductive connecting piece 300 along the second direction is generally 0.6 mm. Generally, the second conductive connecting piece 300 is arranged in the middle of the second main grid 140, and at this time, the distance between the edge of the second conductive connecting piece 300 and the first fine grid line 132 and the second fine grid line 133 is a safety distance of 0.3 mm to 0.5 mm, so as to avoid the conductive connection between the second conductive connecting piece 300 and the first fine grid line 132 and the second fine grid line 133.

[0107] Generally, when the back contact battery 100 is prepared into a back contact battery string 10, the second conductive connecting piece 300 is generally placed by a string welding machine. The string welding machine places the second conductive connecting piece 300 to the back contact battery 100, so as to realize the welding connection between the second conductive connecting piece 300 and the second main grid 140. The placement accuracy of the string welding machine for the second conductive connecting piece 300 is generally within ±0.2 mm.

[0108] The safety distance is set to be within the range of 0.3 mm to 0.5 mm in the present application, which can ensure the accurate placement position of the second conductive connecting piece 300, provide sufficient space for the placement of the second conductive connecting piece 300, avoid the conductive contact (overlap) between the second conductive connecting piece 300 and the first fine grid 130, and further avoid the short circuit.

[0109] Referring to Figure 4 and Figure 5 In an embodiment, the second broken area 151 is symmetrically arranged relative to the first main grid 120. That is, the first main grid 120 is located in the middle region of the second broken area 151, and the distance between the first main grid 120 and the third fine grid line 152 is equal to the distance between the first main grid 120 and the fourth fine grid line 153.

[0110] In this way, the distance between the first main grid 120 and the second fine grid 150 on both sides is equal, and when the first conductive connecting piece 200 is arranged on the first main grid 120, the distance between the first conductive connecting piece 200 and the second fine grid 150 on both sides is substantially equal. Even if there is a certain deviation in the installation of the first conductive connecting piece 200, the conductive contact between the first conductive connecting piece 200 and the second fine grid 150 on one side can be avoided, and further the short circuit can be avoided.

[0111] Referring to Figure 4 and Figure 5 In an embodiment, the size of the second broken area 151 along the second direction ranges from 1.2 mm to 1.6 mm. That is, the distance between the end of the third fine grid line 152 and the end of the adjacent fourth fine grid line 153 is 1.2 mm to 1.6 mm.

[0112] The distance between the first main grid 120 and the third fine grid line 152 is 0.6mm-0.8mm, and the distance between the first main grid 120 and the fourth fine grid line 153 is 0.6mm-0.8mm, so as to avoid the intersection of the first main grid 120 and the second fine grid 150.

[0113] It can be understood that the width of the first conductive connecting piece 200 along the second direction is generally 0.6mm. Generally, the first conductive connecting piece 200 is arranged in the center of the first main grid 120, and the distance between the edge of the first conductive connecting piece 200 and the third fine grid line 152 and the fourth fine grid line 153 is 0.3mm-0.5mm, so as to avoid the conductive connection between the first conductive connecting piece 200 and the third fine grid line 152 and the fourth fine grid line 153.

[0114] Generally, when the back contact battery 100 is prepared into a back contact battery string 10, the first conductive connecting piece 200 is generally placed by a string welding machine. The string welding machine places the first conductive connecting piece 200 on the back contact battery 100, so as to realize the welding connection between the first conductive connecting piece 200 and the first main grid 120. The placement accuracy of the string welding machine is generally within ±0.2mm.

[0115] The safety distance is set to be within 0.3mm-0.5mm, which can ensure the accurate placement position of the first conductive connecting piece 200, provide sufficient space for the placement of the first conductive connecting piece 200, avoid the conductive contact (overlap) between the first conductive connecting piece 200 and the second fine grid 150, and further avoid the short circuit.

[0116] Referring to Figure 4 and Figure 5 In an embodiment, the first main grid 120 includes a first main grid line 121, a second main grid line 122 and a third main grid line 123. The first main grid line 121 is arranged on the inner side of the battery piece 110, the second main grid line 122 and the third main grid line 123 are arranged on the edge of the battery piece 110, the first main grid line 121 and the third main grid line 123 extend along the first direction, the second main grid line 122 extends along the second direction and electrically connects the first main grid line 121 and the third main grid line 123, and the first conductive connecting piece 200 is arranged on the first main grid line 121.

[0117] Since the first fine grid 130 is disconnected at the second main grid 140, the current cannot be collected by a single main grid. Therefore, the back contact battery 100 of the present application separates the first main grid 120 into the first main grid line 121, the second main grid line 122 and the third main grid line 123 in series, the first main grid line 121 is electrically connected with the second fine grid line 133, and the third main grid line 123 is electrically connected with the first fine grid line 132.

[0118] The first main grid line 121 is located in the middle region of the back surface of the cell sheet 110 and extends in the first direction, and the third main grid line 123 is arranged at the edge of the back surface of the cell sheet 110 and extends in the first direction, that is, the first main grid line 121 is parallel to the third main grid line 123 and is arranged in the second direction. In addition, the first conductive connecting piece 200 is arranged in the first direction on the first main grid line 121.

[0119] The second main grid line 122 is located at the edge of the back surface of the cell sheet 110, and the second main grid line 122 extends in the second direction. One end of the second main grid line 122 is electrically connected to the first main grid line 121, and the other end is electrically connected to the second main grid line 122. In this way, the current collected by the third main grid line 123 can be transmitted to the first main grid line 121 through the second main grid line 122. In addition, the shape of the second main grid line 122 is adapted to the shape of the edge of the cell sheet 110, that is, the second main grid line 122 is bent to connect the third main grid line 123.

[0120] When the first electrode main grid 120 of the present application transmits current, the first fine grid line 132 is connected to the third main grid line 123, and the carrier flows along the first fine grid line 132 to the third main grid line 123, and then flows along the second main grid line 122 to the first main grid line 121, forming a current collection path. The second fine grid line 133 is connected to the second main grid line 122, and the carrier flows along the second fine grid line 133 to the first main grid line 121, forming another current collection path.

[0121] Referring to Figure 4 and Figure 5 In an embodiment, the back contact cell 100 further comprises a first electrode pad 160, which is arranged on the back surface of the cell sheet 110 and is electrically connected to the first electrode main grid 120. The first electrode pad 160 is a component for fixedly connecting the first main grid line 121 and the first conductive connecting piece 200. The first electrode pad 160 is arranged on the first main grid line 121 of the first electrode main grid 120, and the first electrode pad 160 is connected to the first conductive connecting piece 200 by welding.

[0122] When the first electrode main grid 120 of the present application transmits current, the first fine grid line 132 is connected to the third main grid line 123, and the carrier flows along the first fine grid line 132 to the third main grid line 123, and then flows along the second main grid line 122 to the first main grid line 121, and then flows to the first electrode pad 160 through the first main grid line 121, forming a current collection path. The second fine grid line 133 is connected to the second main grid line 122, and the carrier flows along the second fine grid line 133 to the first main grid line 121, and then flows to the first electrode pad 160 through the first main grid line 121, forming another current collection path, and then the carrier flows to the first conductive connecting piece 200 through the first electrode pad 160.

[0123] Referring to Figure 4 and Figure 5 In an embodiment, the second main grid 140 includes a first grid line 141, a second grid line 142 and a third grid line 143, the first grid line 141 and the second grid line 142 are located at the inner side of the cell 110, and the third grid line 143 is arranged at the edge of the cell 110, the first grid line 141 and the third grid line 143 extend along the first direction, and the second grid line 142 extends along the second direction and electrically connects the first grid line 141 and the third grid line 143.

[0124] Since the third main grid line 123 is located above the second main grid 140, the current of the upper and lower third fine grid lines 152 cannot be collected by a single main grid. Therefore, the back contact cell 100 of the present application divides the second main grid 140 into the first grid line 141, the second grid line 142 and the third grid line 143 in series, the first grid line 141 is electrically connected to the upper third grid line 143, and the third grid line 143 is electrically connected to the lower third fine grid line 152.

[0125] The first grid line 141 is located in the middle area of the back of the cell 110 and extends along the first direction, and the first grid line 141 is also located in the area surrounded by the first main grid line 121, the second main grid line 122 and the third main grid line 123. The third grid line 143 is arranged at the edge of the back of the cell 110 and extends along the first direction, that is, the first grid line 141 and the third grid line 143 are parallel and arranged in the second direction.

[0126] The second grid line 142 extends along the second direction, one end of the second grid line 142 is electrically connected to the first grid line 141, and the other end is electrically connected to the second grid line 142. In this way, the current collected by the third grid line 143 can be transmitted to the first grid line 141 through the second grid line 142. In the present application, the fourth fine grid line 153 connects another second main grid 140, which is not described in the present application.

[0127] When the first main grid 120 of the present application transmits current, the lower third fine grid line 152 is connected to the third grid line 143, the carriers flow along the third fine grid line 152 to the third grid line 143, and then flow along the second grid line 142 to the second electrode pad 170 (volume below), forming a current collection path. The upper third fine grid line 152 is connected to the first grid line 141, the carriers flow along the third fine grid line 152 to the first grid line 141, forming another current collection path.

[0128] Referring to Figure 4 and Figure 5In an embodiment, the back contact cell 100 further comprises a second electrode pad 170, which is disposed on the back surface of the cell sheet 110 and electrically connected to the second electrode main grid 140. The second electrode pad 170 is a component fixedly connected to the first grid line 141 and the second conductive connecting piece 300. The second electrode pad 170 is disposed on the first grid line 141 of the second electrode main grid 140, and the second electrode pad 170 is connected to the second conductive connecting piece 300 by welding.

[0129] In addition, the third grid line 143 and the second electrode pad 170 are not directly connected in series, but are connected in series through the second grid line 142 in the second direction (horizontal direction). Optionally, the number of the second grid line 142 is one or each, and is connected in series between the third grid line 143 and the second electrode pad 170.

[0130] When the second electrode main grid 140 of the present application transmits current, the third fine grid line 152 is connected to the first grid line 141, the carriers flow along the third fine grid line 152 to the second grid line 142, and then flow to the second electrode pad 170 through the second grid line 142, forming a current collection path, and then the carriers flow to the second conductive connecting piece 300 through the second electrode pad 170.

[0131] Referring to Figure 4 and Figure 5 In an embodiment, the third main grid line 123 is collinear with the third grid line 143, and there is a set spacing between the third main grid line 123 and the third grid line 143. That is, the third main grid line 123 extends in the first direction (vertical direction), and the third grid line 143 extends in the first direction (vertical direction).

[0132] The third main grid line 123 and the third grid line 143 are located on the same straight line, and the third main grid line 123 and the third grid line 143 are disconnected, that is, the third main grid line 123 and the third grid line 143 are not connected, to avoid short circuit between the first electrode main grid 120 and the second electrode main grid 140.

[0133] Referring to Figure 4 and Figure 5 In an embodiment, the set spacing has a size range of 1mm-1.6mm. The distance between the third main grid line 123 and the third grid line 143 in the first direction ranges from 1mm to 1.6mm. In this way, a certain spacing can be provided between the third main grid line 123 and the third grid line 143.

[0134] Referring to Figure 4 and Figure 5 In an embodiment, there is a predetermined interval between the first grid line 141 and the second main grid line 122. In Figure 4 and Figure 5In some embodiments, the first grid line 141 is located in the area surrounded by the first main grid line 121, the second main grid line 122 and the third main grid line 123, and a predetermined gap is formed between the top of the first grid line 141 and the second main grid line 122 to avoid contact between the first grid line 141 and the second main grid line 122.

[0135] Referring to Figure 4 and Figure 5 In some embodiments, the first grid line 141 has a size in the first direction ranging from 2.5 mm to 5.75 mm. That is, the size of the first grid line 141 in the vertical direction ranges from 2.5 mm to 5.75 mm, which can avoid contact between the first grid line 141 and the second main grid line 122.

[0136] Referring to Figure 4 and Figure 5 In some embodiments, the back contact battery 100 further comprises a plurality of insulation portions 180, which are respectively arranged at the ends of the first main grid 120 located in the first disconnection area 131, and / or the plurality of insulation portions 180 are respectively arranged at the ends of the second fine grid 150 located in the second disconnection area 151.

[0137] In the first disconnection area 131, the insulation portion 180 covers the first fine grid 130 directly above the second conductive connector 300 on both sides, that is, the insulation portion 180 covers the ends of the first fine grid line 132 and the second fine grid line 133. In this way, the first fine grid 130 and the second conductive connector 300 can be further insulated and designed to avoid conductive contact between the first fine grid 130 and the second conductive connector 300.

[0138] In the second disconnection area 151, the insulation portion 180 covers the second fine grid 150 directly above the first conductive connector 200 on both sides, that is, the insulation portion 180 covers the ends of the third fine grid line 152 and the fourth fine grid line 153. In this way, the second fine grid 150 and the first conductive connector 200 can be further insulated and designed to avoid conductive contact between the second fine grid 150 and the first conductive connector 200.

[0139] Optionally, the insulation portion 180 is an insulating glue. Of course, in other embodiments of the present application, the insulation portion 180 can also be other components that can achieve insulating connection.

[0140] The back contact battery 100 of the present application breaks the first fine grid 130 at the second main grid 140 to form a first breaking area 131, so that the first fine grid 130 is not electrically connected to the second main grid 140, and breaks the second fine grid 150 at the first main grid 120 to form a second breaking area 151, so that the second fine grid 150 is not electrically connected to the first main grid 120. In this way, the short circuit problem caused by the absence of glue or the puncture of insulating glue by the solder strip barb can be avoided, and the use performance of the back contact battery 100 can be ensured.

[0141] The back contact battery 100 sets the first breaking area 131 on the first fine grid 130 to avoid the second main grid 140 and the second conductive connecting piece 300, and sets the second breaking area 151 on the second fine grid 150 to avoid the first main grid 120 and the first conductive connecting piece 200. In this way, the optimization design of the high-risk position of the four corners of the back contact battery 100 is realized, so that the conductive connecting piece only intersects with the fine grid of the same polarity, and does not intersect with the fine grid of the opposite polarity, which can prevent the conductive connecting piece from being short-circuited with the fine grid of the opposite polarity.

[0142] At the same time, the breaking distance of the first fine grid 130 and the second fine grid 150 is limited to be within the range of 1.2mm~1.6mm, and a safety distance of 0.3mm~0.5mm is reserved between the conductive connecting piece and the fine grid of the opposite polarity, that is, even if there is a certain error in the placement accuracy of the conductive connecting piece, the safety distance can also prevent the conductive connecting piece from being short-circuited with the fine grid of the opposite polarity.

[0143] Referring to Figure 4 , the present application also provides a back contact battery string 10, which comprises a first conductive connecting piece 200, a second conductive connecting piece 300 and a plurality of back contact batteries 100 according to any one of the above embodiments. The first conductive connecting piece 200 is electrically connected to the first main grid 120 of two adjacent back contact batteries 100, and is located at the second breaking area 151 of the back contact battery 100. The second conductive connecting piece 300 is electrically connected to the second main grid 140 of the back contact battery 100, and is located at the first breaking area 131 of the back contact battery 100.

[0144] The back contact battery string 10 of the present application connects two adjacent back contact batteries 100 by the first conductive connecting piece 200 and the second conductive connecting piece 300. Figure 5 In the embodiment, only two back contact battery strings 10 are connected, and in other embodiments of the present application, the above-mentioned connection can be continuously repeated to connect three or more back contact battery strings 10 into a back contact battery string 10.

[0145] The back contact battery string 10 of the present application, after using the back contact battery 100 described above, can avoid the first conductive connecting piece 200 electrically contacting the second fine grid 150, avoid the second conductive connecting piece 300 electrically contacting the first fine grid 130, avoid the short circuit problem caused by the absence of glue or the barb of the solder strip piercing the insulating glue, and ensure the use performance of the back contact battery 100.

[0146] Referring to Figure 4 In an embodiment, the distance between the first conductive connecting piece 200 and the second fine grid 150 of the back contact battery 100 is in the range of 0.3mm-0.5mm. It can be understood that the distance between the first main grid 120 and the second fine grid 150 on both sides is in the range of 0.6mm-0.8mm.

[0147] It can be understood that the width dimension of the first conductive connecting piece 200 along the second direction is generally 0.6mm. Generally, the first conductive connecting piece 200 is centrally arranged on the first main grid 120, at this time, the distance between the edge of the first conductive connecting piece 200 and the third fine grid line 152 and the fourth fine grid line 153 is a safety distance of 0.3mm-0.5mm, avoiding the electrically connecting of the first conductive connecting piece 200 and the third fine grid line 152 and the fourth fine grid line 153.

[0148] Generally, when the back contact battery 100 is prepared into a back contact battery string 10, the first conductive connecting piece 200 is generally placed by a string welding machine. The string welding machine places the first conductive connecting piece 200 to the back contact battery 100, realizing the welding connection of the first conductive connecting piece 200 and the first main grid 120. The placement accuracy of the string welding machine for the first conductive connecting piece 200 is generally within ±0.2mm.

[0149] The present application sets the safety distance in the range of 0.3mm-0.5mm, which can ensure the accurate placement position of the first conductive connecting piece 200, provide sufficient space for the placement of the first conductive connecting piece 200, avoid the electrically contacting (lapping) of the first conductive connecting piece 200 and the second fine grid 150, and further avoid the short circuit situation.

[0150] Referring to Figure 5 Figure 4 Figure 5 Figures 1 to 5 Figure 1 Figures 2 to 5 Figures 2 to 5 In an embodiment, the distance between the second conductive connecting piece 300 and the first fine grid 130 of the back contact battery 100 is in the range of 0.3mm-0.5mm. It can be understood that the distance between the second main grid 140 and the first fine grid 130 on both sides is in the range of 0.6mm-0.8mm.

[0151] The width dimension of the second conductive connecting piece 300 along the second direction is generally 0.6 mm. Generally, the second conductive connecting piece 300 is arranged in the middle of the second main grid 140, and the distance between the edge of the second conductive connecting piece 300 and the first and second fine grid lines 132 and 133 is a safety distance of 0.3-0.5 mm, so as to avoid the conductive connection between the second conductive connecting piece 300 and the first and second fine grid lines 132 and 133.

[0152] Generally, when the back contact cell 100 is prepared into a back contact cell string 10, the second conductive connecting piece 300 is generally placed by a string welding machine. The string welding machine places the second conductive connecting piece 300 on the back contact cell 100 to realize the welding connection between the second conductive connecting piece 300 and the second main grid 140. The placement accuracy of the string welding machine for the second conductive connecting piece 300 is generally within ±0.2 mm.

[0153] The safety distance in the present application is within the range of 0.3-0.5 mm, which can ensure the accurate placement position of the second conductive connecting piece 300, provide sufficient space for the placement of the second conductive connecting piece 300, avoid the conductive contact (overlap) between the second conductive connecting piece 300 and the first fine grid 130, and further avoid the short circuit.

[0154] The present application also provides a back contact photovoltaic module, which comprises a cover plate, a back plate, and the back contact cell string 10 in any of the above embodiments. The cover plate and the back plate are arranged on both sides of the back contact cell string 10, and the cover plate, the back plate, and the back contact cell string 10 are encapsulated by an encapsulation process. The back contact photovoltaic module of the present application can encapsulate the back contact cell string 10 of the above embodiments by the cover plate and the back plate to realize the preparation of the back contact photovoltaic module.

[0155] In the lamination process (140℃, 20 min), the hardness of the surface of the insulating part 180 decreases after heating. Since the conductive connecting piece does not cross the fine grid with opposite polarity, even if the head of the first and second conductive connecting pieces 200 and 300 has a barb, the barb pierces the insulating glue, and the conductive connecting piece does not conductively contact the fine grid with opposite polarity, thereby avoiding the short circuit problem.

[0156] The technical features of the above embodiments can be combined in any manner. To make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist, they should be considered as the scope of the present application.

[0157] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A back contact cell, characterized in that, The battery piece (110) comprises: a first main grid (120) disposed on the back of the battery piece (110) and used for electrically connecting a first conductive connector (200) of the back contact battery string (10); a plurality of first fine grids (130) disposed in parallel and at intervals along a first direction on the back of the battery piece (110) and extending along a second direction, and each of the plurality of first fine grids (130) is electrically connected to the first main grid (120); a second main grid (140) disposed on the back of the battery piece (110) and used for electrically connecting a second conductive connector (300) of the back contact battery string (10); and a plurality of second fine grids (150) disposed in parallel and at intervals along the first direction on the back of the battery piece (110) and extending along the second direction, and each of the plurality of second fine grids (150) is electrically connected to the second main grid (140); wherein the plurality of first fine grids (130) and the plurality of second fine grids (150) are alternately distributed along the extension direction of the first main grid (120), the first fine grid (130) is disconnected at the second main grid (140) to form a first disconnection area (131), the second fine grid (150) is disconnected at the first main grid (120) to form a second disconnection area (151), the first conductive connector (200) is disposed in the second disconnection area (151) and has a preset interval with the second fine grid (150), and the second conductive connector (300) is disposed in the first disconnection area (131) and has a preset interval with the first fine grid (130). Each of the first fine grid (130) comprises a plurality of first fine grid lines (132) and a plurality of second fine grid lines (133), the plurality of first fine grid lines (132) and the plurality of second fine grid lines (133) are alternately distributed along the second direction, and adjacent first fine grid lines (132) and second fine grid lines (133) are located on both sides of the second main grid (140) and have a preset interval therebetween to form the first disconnection area (131); 2. The back contact cell of claim 1, wherein, and / or, each of the second fine grid (150) comprises a plurality of third fine grid lines (152) and a plurality of fourth fine grid lines (153), the plurality of third fine grid lines (152) and the plurality of fourth fine grid lines (153) are alternately distributed along the second direction, and adjacent third fine grid lines (152) and fourth fine grid lines (153) are located on both sides of the first main grid (120) and have a preset interval therebetween to form the second disconnection area (151). The first disconnection area (131) is symmetrically disposed relative to the second main grid (140); 3. The back contact cell of claim 1, wherein, and / or, the second disconnection area (151) is symmetrically disposed relative to the first main grid (120); and / or, the size range of the first disconnection area (131) along the second direction is 1.2mm-1.6mm; ​ And / or, the second disconnecting area (151) has a size ranging from 1.2mm to 1.6mm along the second direction.

4. The back contact cell of claim 1, wherein, The first polar main grid (120) comprises a first main grid line (121), a second main grid line (122) and a third main grid line (123), the first main grid line (121) is arranged at the inner side of the cell sheet (110), the second main grid line (122) and the third main grid line (123) are arranged at the edge of the cell sheet (110), the first main grid line (121) and the third main grid line (123) extend along the first direction, the second main grid line (122) extends along the second direction and electrically connects the first main grid line (121) and the third main grid line (123), and the first conductive connecting piece (200) is arranged on the first main grid line (121). And / or, the second polar main grid (140) comprises a first grid line (141), a second grid line (142) and a third grid line (143), the first grid line (141) and the second grid line (142) are arranged at the inner side of the cell sheet (110), and the third grid line (143) is arranged at the edge of the cell sheet (110), the first grid line (141) and the third grid line (143) extend along the first direction, the second grid line (142) extends along the second direction and electrically connects the first grid line (141) and the third grid line (143).

5. The back contact cell of claim 4, wherein, The third main grid line (123) and the third grid line (143) are collinear, and there is a set interval between the third main grid line (123) and the third grid line (143), and the size of the set interval ranges from 1mm to 1.6mm; And / or, there is a predetermined interval between the first grid line (141) and the second main grid line (122); And / or, the size of the first grid line (141) along the first direction ranges from 2.5mm to 5.75mm.

6. The back contact cell according to any of claims 1 to 5, characterized in that, The back contact cell (100) further comprises a first polar pad (160), the first polar pad (160) is arranged on the back of the cell sheet (110) and electrically connected with the first polar main grid (120); The back contact cell (100) further comprises a second polar pad (170), the second polar pad (170) is arranged on the back of the cell sheet (110) and electrically connected with the second polar main grid (140).

7. The back contact cell according to any of claims 1 to 5, characterized in that, The back contact cell (100) further comprises a plurality of insulation parts (180), the plurality of insulation parts (180) are respectively arranged at the end of the first polar main grid (120) located at the first disconnecting area (131), and / or the plurality of insulation parts (180) are respectively arranged at the end of the second polar fine grid (150) located at the second disconnecting area (151).

8. A back contact cell string characterized in that, The back contact cell (100) comprises a first conductive connecting piece (200), a second conductive connecting piece (300) and a plurality of back contact cells (100) as claimed in any one of claims 1 to 7. The first conductive connecting piece (200) is electrically connected to the first polar main grid (120) of two adjacent back contact cells (100) and is located at the second disconnecting area (151) of the back contact cell (100), and the second conductive connecting piece (300) is electrically connected to the second polar main grid (140) of the back contact cell (100) and is located at the first disconnecting area (131) of the back contact cell (100).

9. The back contact cell string of claim 8, wherein, The distance between the first conductive connecting piece (200) and the second polar fine grid (150) of the back contact cell (100) ranges from 0.3mm to 0.5mm; And / or, the distance between the second conductive connecting piece (300) and the first polar fine grid (130) of the back contact cell (100) ranges from 0.3mm to 0.5mm.

10. A back contact photovoltaic module characterized by, The back contact cell string (10) comprises a cover plate, a back plate and a plurality of back contact cells as claimed in claim 8 or 9; The cover plate and the back plate are arranged on both sides of the back contact cell string (10), and the cover plate, the back plate and the back contact cell string (10) are packaged by using a packaging process.

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