Back-contact solar cell and preparation method therefor, and photovoltaic module

Abstract

The present application relates to the technical field of photovoltaics. Provided are a back-contact solar cell and a preparation method therefor, and a photovoltaic module. The back-contact solar cell comprises a cell body, wherein the cell body comprises: current-collecting doped regions, which comprise first current-collecting doped regions and second current-collecting doped regions that extend along a first direction and are alternately distributed at intervals along a second direction; busbar doped regions, which comprise first busbar doped regions and second busbar doped regions that extend along the second direction and are alternately distributed at intervals along the first direction; and a positioning region, which has current-collecting doped regions of at least one polarity on two sides thereof along the first direction, wherein a first isolation region is provided between the current-collecting doped regions of at least one polarity and at least one side of the positioning region along the first direction. The present application achieves a more accurate positioning effect and can solve the problem of inefficient carrier collection caused by dead zones.

Description

Back contact cell, preparation method thereof and photovoltaic module TECHNICAL FIELD

[0001] The present application relates to the technical field of photovoltaics, in particular to a back contact cell, a preparation method thereof and a photovoltaic module. BACKGROUND

[0002] The back contact cell can make full use of sunlight due to its structure without grid lines on the light-receiving surface, so that it has higher efficiency, and due to the structure without grid lines on the light-receiving surface, the appearance of the module end is more beautiful, so it has broad application prospects.

[0003] The design of the confluence area, the current collecting area and the isolation area of different polarities in the back contact cell is relatively complex, and how to achieve high-precision design becomes a technical problem. At present, the positioning points are mainly increased to achieve the above complex design.

[0004] In the prior art, positioning is mainly performed through cross marks, dots and cell edge grabbing. However, the current positioning method has the problem of poor positioning effect. SUMMARY

[0005] The present application provides a back contact cell, a preparation method thereof and a photovoltaic module, aiming to solve the problem of poor positioning effect in the existing back contact cell.

[0006] In a first aspect, the present application provides a back contact cell, comprising: a cell body; the cell body comprises:

[0007] a current collecting doped area, comprising a first current collecting doped area and a second current collecting doped area, the first current collecting doped area and the second current collecting doped area extend along a first direction and are alternately and spacedly distributed along a second direction; the first direction is different from the second direction; the first current collecting doped area and the second current collecting doped area are different in doping type;

[0008] a confluence doped area, comprising a first confluence doped area and a second confluence doped area, the first confluence doped area and the second confluence doped area extend along the second direction and are alternately and spacedly distributed along the first direction; the first confluence doped area and the second confluence doped area are different in doping type; the first current collecting doped area and the first confluence doped area are of the same polarity, and the second current collecting doped area and the second confluence doped area are of the same polarity; at least part of the first current collecting doped area and the first confluence doped area intersect, and at least part of the second current collecting doped area and the second confluence doped area intersect;

[0009] The positioning area has the current collecting doped area of at least one polarity on both sides in the first direction, and the current collecting doped area of at least one polarity has the first isolation area on at least one side of the positioning area in the first direction; the positioning area has the current collecting doped area of at least one polarity on both sides in the second direction, and the current collecting doped area of at least one polarity has the second isolation area on both sides of the positioning area in the second direction.

[0010] In the present application, the positioning area has the current collecting doped area of at least one polarity on both sides in the first direction, which can reduce the area of the dead zone and improve the current collection efficiency. The positioning area has the current collecting doped area of at least one polarity on both sides in the second direction, and the current collecting doped area of at least one polarity has the second isolation area on both sides of the positioning area in the second direction, thereby separating the positioning area from the second direction and further improving the positioning accuracy. The positioning area has the current collecting doped area of at least one polarity on both sides in the first direction, and the current collecting doped area of at least one polarity has the first isolation area on at least one side of the positioning area in the first direction, similarly, in the case that the current collecting doped area of at least one polarity has the first isolation area on both sides of the positioning area in the first direction, the positioning area is separated from the first direction, further improving the positioning accuracy.

[0011] Optionally, in the first direction, the positioning area is located between the adjacent first current collecting doped area and the second current collecting doped area.

[0012] In the present application, in the first direction, the positioning area is designed to be located between the adjacent first current collecting doped area and the second current collecting doped area, and in the case that the back contact cell further includes a current collecting grid line located on the current collecting doped area, the positioning area is designed to be located between the adjacent first current collecting grid line and the second current collecting grid line, which can effectively solve the positioning problem between the grid line and the doped area and improve the positioning accuracy.

[0013] Optionally, the current collecting doped area is only arranged at at least one end of the cell body along the second direction, and in the second direction, the current collecting doped area and the positioning area have a spacing.

[0014] Optionally, the positioning area has the current collecting doped area of opposite polarity on both sides in the first direction, and the current collecting doped area of opposite polarity has the first isolation area on both sides of the positioning area in the first direction, and the first isolation area and the second isolation area form a continuous isolation area. The positioning area has the current collecting doped area of opposite polarity on both sides in the first direction, which can solve the problem of poor carrier collection caused by the dead zone. The first isolation area and the second isolation area form a continuous isolation area, which is beneficial to the accuracy of positioning.

[0015] Optionally, the back contact cell further comprises:

[0016] The first and second current collecting grid lines on the opposite polarity current collecting doped regions in the first direction are both spaced from the positioning region.

[0017] Optionally, the positioning region has a size L1 in the first direction, and a distance L2 between adjacent opposite polarity current collecting doped regions in the first direction; L2>L1>L2 / 2; and / or,

[0018] The positioning region has a size L3 in the second direction, and a distance L4 between adjacent same polarity current collecting doped regions in the second direction; L4>L3>L4 / 2.

[0019] Optionally, a third isolation region is arranged between the first and second current collecting doped regions;

[0020] The third isolation region has a size L5 in the second direction.

[0021] A first isolation region on one side of the positioning region in the first direction has a size L6 in the first direction.

[0022] A second isolation region on one side of the positioning region in the second direction has a size L7 in the second direction.

[0023] 1.5×L5>L6>L5; and / or, L5=L7.

[0024] Optionally, the back contact cell further comprises: a positioning electrode point, a normal projection of the positioning electrode point on the cell body is located in the positioning region; in the second direction: the positioning electrode point has a size L8, and the positioning region has a size L3; 0.4×L3

[0025] Optionally, the positioning region has same polarity current collecting doped regions on both sides in the first direction; the same polarity current collecting doped regions in the first direction and both sides of the positioning region have the first isolation region, and the first and second isolation regions form a continuous isolation region.

[0026] Optionally, the back contact cell further comprises:

[0027] The first collection grid lines or the second collection grid lines are continuous on the collection doped regions with the same polarity in the first direction.

[0028] Optionally, the positioning region has the collection doped regions with the same polarity on both sides in the second direction, and the collection doped regions with the same polarity in the second direction have the second isolation region on both sides of the positioning region.

[0029] Optionally, the positioning region is distributed in the back contact cell about an axis of symmetry parallel to the second direction.

[0030] Optionally, the positioning region is a first collection doped region or a second collection doped region.

[0031] The back contact cell has at least two positioning regions collinear in the first direction; all the positioning regions collinear in the first direction are first collection doped regions or second collection doped regions.

[0032] Optionally, the number of the positioning regions is 2-4.

[0033] Optionally, the area of one positioning region is 0.5mm 2 -1.5mm 2 .

[0034] Optionally, the positioning region is a P-type collection doped region.

[0035] Optionally, the back contact cell further comprises:

[0036] The first bus grid lines on the first bus doped regions and the second bus grid lines on the second bus doped regions; at least part of the first collection grid lines and the first bus grid lines intersect, and at least part of the second collection grid lines and the second bus grid lines intersect.

[0037] Optionally, the back contact cell further comprises:

[0038] A plurality of electrode pads on the bus grid lines; the plurality of electrode pads comprises: at least two positioning electrode pads corresponding to the positioning regions and away from the geometric center of the back contact cell; the shape of the positioning electrode pads is different from the shape of the remaining electrode pads in the plurality of electrode pads.

[0039] At least two of the positioning electrode disks are distributed in the back contact cell about an axis of symmetry parallel to the second direction.

[0040] Optionally, the back contact cell further comprises: an insulating glue;

[0041] The insulating glue is located at least on the current collecting bus lines adjacent to the current collecting grid lines.

[0042] The orthographic projection of the insulating glue on the cell body is separated from the positioning area.

[0043] In a second aspect of the present application, a back contact cell is provided, comprising: a cell body; the cell body comprising: a plurality of cell units and a division area between adjacent cell units, the cell unit comprising:

[0044] A current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first current collecting doped region and the second current collecting doped region extending along a first direction and alternately and spacedly distributed along a second direction, the first direction being different from the second direction; the first current collecting doped region and the second current collecting doped region having different doping types;

[0045] A bus doped region, comprising a first bus doped region and a second bus doped region, the first bus doped region and the second bus doped region extending along the second direction and alternately and spacedly distributed along the first direction; the first bus doped region and the second bus doped region having different doping types; the first current collecting doped region and the first bus doped region having the same polarity, the second current collecting doped region and the second bus doped region having the same polarity; at least part of the first current collecting doped region and the first bus doped region intersecting, at least part of the second current collecting doped region and the second bus doped region intersecting;

[0046] A positioning area, the positioning area having the current collecting doped region of at least one polarity on both sides in the first direction, the current collecting doped region of the at least one polarity having a first isolation region on at least one side of the positioning area in the first direction; the positioning area having the current collecting doped region of at least one polarity on both sides in the second direction, the current collecting doped region of the at least one polarity having a second isolation region on both sides of the positioning area in the second direction;

[0047] All of the positioning areas of the plurality of cell units are symmetric about the center of the cell body.

[0048] Optionally, in the first direction, the positioning area is located between the adjacent first bus doped region and the second bus doped region.

[0049] Optionally, the positioning region passes the middle line between the adjacent first and second busbar doped regions.

[0050] Optionally, the back contact cell is sliced along the segmentation region to obtain a plurality of back contact cells according to the first aspect.

[0051] In a third aspect, the present application provides a method for manufacturing a back contact cell, comprising:

[0052] providing a silicon substrate; the silicon substrate comprises a first surface and a second surface opposite to each other;

[0053] forming a first doped layer on the first surface of the silicon substrate;

[0054] removing part of the first doped layer to expose part of the first surface, and the remaining first doped layer comprises a plurality of first current collecting doped regions extending in a first direction and spaced apart in a second direction, and a plurality of first busbar doped regions extending in the second direction and spaced apart in the first direction; at least part of the first current collecting doped regions and the first busbar doped regions intersect; part of the first current collecting doped regions covers a positioning region, and the first doped layer around the positioning region is removed; wherein the first direction is different from the second direction;

[0055] forming a second doped layer on the exposed first surface and the remaining first doped layer; the first doped layer and the second doped layer are of different doping types;

[0056] removing part of the second doped layer to expose the plurality of first current collecting doped regions and the plurality of first busbar doped regions, to form first current collecting doped regions and second current collecting doped regions extending in the first direction and alternately spaced apart in the second direction, first busbar doped regions and second busbar doped regions extending in the second direction and alternately spaced apart in the first direction, and the positioning region; at least part of the second current collecting doped regions and the second busbar doped regions intersect;

[0057] wherein the positioning region has at least one type of current collecting doped region on both sides in the first direction, and at least one first isolation region between the at least one type of current collecting doped region and at least one side of the positioning region in the first direction; the positioning region has at least one type of current collecting doped region on both sides in the second direction, and at least one second isolation region between the at least one type of current collecting doped region and both sides of the positioning region in the second direction.

[0058] Optionally, in the first direction, the positioning region is located between the adjacent first and second busbar doped regions.

[0059] Optionally, the method further comprises: multiple gate line preparation, wherein,

[0060] a first gate line preparation is performed with the positioning region as a positioning point, and a positioning electrode point is formed in the positioning region;

[0061] a remaining gate line preparation is performed with the positioning electrode point as a positioning point.

[0062] Optionally, the partial region removed from the first doped layer and the partial region removed from the second doped layer partially overlap, so that at least part of the region around the positioning region is exposed silicon substrate, and the exposed silicon substrate forms the first and second isolation regions.

[0063] In a fourth aspect of the present application, a photovoltaic module is provided, comprising: a plurality of back contact cells according to the first aspect.

[0064] In a fifth aspect of the present application, a photovoltaic module is provided, comprising:

[0065] a plurality of back contact cells; the back contact cell comprises: a cell body, the cell body comprising: a current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first and second current collecting doped regions extending in a first direction and alternately and spacedly distributed in a second direction; the first direction is different from the second direction; the first and second current collecting doped regions are of different doping types;

[0066] the back contact cell further comprises: a current collecting gate line on the cell body, the current collecting gate line comprising a first current collecting gate line on the first current collecting doped region, and a second current collecting gate line on the second current collecting doped region;

[0067] an interconnector, the interconnector electrically connecting two adjacent back contact cells, one end of the interconnector being electrically connected to the second current collecting gate line of one of the two adjacent back contact cells, and the other end of the interconnector being electrically connected to the first current collecting gate line of the other of the two adjacent back contact cells;

[0068] the cell body further comprises:

[0069] The positioning region has the current collecting doped region of at least one polarity on both sides in the first direction, and the current collecting doped region of at least one polarity has the first isolation region on at least one side of the positioning region in the first direction; the positioning region has the current collecting doped region of at least one polarity on both sides in the second direction, and the current collecting doped region of at least one polarity has the second isolation region on both sides of the positioning region in the second direction.

[0070] Optionally, in the first direction, the positioning region is located between adjacent interconnections.

[0071] The back contact cell piece, the preparation method thereof and the photovoltaic module have the same or similar beneficial effects, and thus the description is not repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0072] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0073] FIG. 1 shows a partial structure schematic diagram of a first back contact cell piece in the embodiments of the present application;

[0074] FIG. 2 shows a partial structure schematic diagram of a second back contact cell piece in the embodiments of the present application;

[0075] FIG. 3 shows a partial structure schematic diagram of a third back contact cell piece in the embodiments of the present application;

[0076] FIG. 4 shows a partial structure schematic diagram of a fourth back contact cell piece in the embodiments of the present application;

[0077] FIG. 5 shows a partial structure schematic diagram of a fifth back contact cell piece in the embodiments of the present application;

[0078] FIG. 6 shows a partial structure schematic diagram of a sixth back contact cell piece in the embodiments of the present application;

[0079] FIG. 7 shows a partial structure schematic diagram of a seventh back contact cell piece in the embodiments of the present application;

[0080] FIG. 8a and FIG. 8b show a position schematic diagram of the busbar doped region and the positioning region in the embodiments of the present application;

[0081] FIG. 9 shows a comparison diagram of positioning accuracy test results of different positioning modes;

[0082] FIG. 10 shows a comparison chart of short-circuit current test results of the back contact cell corresponding to the positioning area in different settings;

[0083] FIG. 11 shows a comparison chart of short-circuit current test results of the back contact cell corresponding to the positioning area in different areas.

[0084] FIG. 11 shows a comparison chart of short-circuit current test results of the back contact cell corresponding to the positioning area in different areas. DETAILED DESCRIPTION

[0085] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0086] The present application provides a back contact cell. In a normal working process of the back contact cell, the side mainly receiving light is the front side, and the back side is opposite to the front side. The back contact cell comprises a cell body containing a PN junction for separating carriers. In FIGS. 1 to 7 and FIGS. 8a and 8b, the left-right direction is a first direction M, and the up-down direction is a second direction Q. Referring to FIGS. 1 to 4, the cell body comprises a current collecting doped region, which comprises a first current collecting doped region 11 and a second current collecting doped region 12. The first current collecting doped region 11 and the second current collecting doped region 12 extend along the first direction M and are alternately and spacedly distributed along the second direction Q. The first direction M is different from the second direction Q, and the included angle between the first direction M and the second direction Q is not limited. For example, the first direction M and the second direction Q can be perpendicular. The number of the first current collecting doped region 11 and the second current collecting doped region 12 is not limited. The doping types of the first current collecting doped region 11 and the second current collecting doped region 12 are different. One of the first current collecting doped region 11 and the second current collecting doped region 12 is an N-type current collecting doped region, and the other is a P-type current collecting doped region.

[0087] The battery body further comprises: a current-collecting doped region, comprising a first current-collecting doped region and a second current-collecting doped region, the first current-collecting doped region and the second current-collecting doped region extend along a second direction Q and are alternately and spacedly distributed along a first direction M, the first current-collecting doped region and the second current-collecting doped region are different in doped type, one of which is an N-type current-collecting doped region and the other is a P-type current-collecting doped region. The doped type of the first current-collecting doped region is the same as that of the first current-collecting doped region, and the doped type of the second current-collecting doped region is the same as that of the second current-collecting doped region. At least part of the first current-collecting doped region intersects the first current-collecting doped region, and at least part of the second current-collecting doped region intersects the second current-collecting doped region. The width of the current-collecting doped region can be greater than the width of the current-collecting doped region. The direction in which the width of the current-collecting doped region is located is parallel to the first direction M, and the direction in which the width of the current-collecting doped region is located is parallel to the second direction Q. The carriers in the first current-collecting doped region can be collected to the first current-collecting doped region, and the carriers in the second current-collecting doped region can be collected to the second current-collecting doped region.

[0088] Referring to FIG. 1 to FIG. 7, the battery body further comprises a positioning area 13, in the first direction M, the two sides of the positioning area 13 have at least one polarity of current collecting doped area, and in the first direction M, the at least one polarity of current collecting doped area has a first isolation area 14 on at least one side of the positioning area 13. Here, one polarity refers to N-type or P-type. That is, in the first direction M, when the two sides of the positioning area 13 are adjacent to the first current collecting doped area and the second current collecting doped area respectively, at least one side of the positioning area 13 has a first isolation area on the adjacent first current collecting doped area or the second current collecting doped area. Alternatively, in the first direction M, when the two sides of the positioning area 13 are adjacent to the first current collecting doped area only, at least one side of the positioning area 13 has a first isolation area on the adjacent first current collecting doped area. Alternatively, in the first direction M, when the two sides of the positioning area 13 are adjacent to the second current collecting doped area only, at least one side of the positioning area 13 has a first isolation area on the adjacent second current collecting doped area. The current collecting doped area with at least one polarity on the two sides of the positioning area in the first direction M can reduce the area of the dead zone and improve the current collection efficiency. The current collecting doped area with at least one polarity on the two sides of the positioning area in the first direction M has a first isolation area on at least one side of the positioning area, and in the case that the current collecting doped area has a first isolation area on both sides of the positioning area, the positioning area can be separated out from the first direction M, further improving the positioning accuracy. The current collecting doped area with at least one polarity on the two sides of the positioning area 13 in the second direction Q has a second isolation area 17 on both sides of the positioning area in the second direction Q, thereby achieving uniform collection of carriers on the entire surface and achieving sufficient collection of carriers on both sides of the positioning area 13. Here, one polarity refers to N-type or P-type. That is, in the second direction Q, when the two sides of the positioning area 13 are adjacent to the first current collecting doped area and the second current collecting doped area respectively, both sides of the positioning area 13 have a second isolation area on the adjacent first current collecting doped area and the second current collecting doped area. Alternatively, in the second direction Q, when the two sides of the positioning area 13 are adjacent to the first current collecting doped area only, both sides of the positioning area 13 have a second isolation area on the adjacent first current collecting doped area. Alternatively, in the second direction Q, when the two sides of the positioning area 13 are adjacent to the second current collecting doped area only, both sides of the positioning area 13 have a second isolation area on the adjacent second current collecting doped area. It should be noted that in the second direction Q, a third isolation area 15 is provided between the adjacent first current collecting doped area and the second current collecting doped area, and the second isolation area 17 can partially overlap the third isolation area 15, or the third isolation area 15 directly exists as the second isolation area 17, which can improve the patterning capacity and reduce the cost.Alternatively, the second isolation region 17 can also be separated from the third isolation region 15, and no specific limitation is made in this regard.

[0089] The positioning region has a current collecting doped region with at least one polarity on both sides in the second direction Q, and the current collecting doped region has a second isolation region on both sides of the positioning region, thereby separating the positioning region from the second direction Q, and further improving the positioning accuracy.

[0090] Alternatively, in FIGS. 1-8b, in the first direction M, the positioning region 13 can be located between adjacent first and second busbar doped regions. In this application, being located between adjacent first and second busbar doped regions means being located between the first and second busbar doped regions and their extension lines, wherein the first and second busbar doped regions can include the busbar doped regions corresponding to the busbar lines in FIG. 8a, can also include the busbar doped regions corresponding to the busbar lines at the end of the second direction in FIG. 8b, and can also include the busbar doped regions corresponding to the interconnection structures (such as pads), at this time, the corresponding battery piece can only include the current collecting lines and the interconnection structures, without the busbar lines, and the current collecting doped region corresponding to the current collecting lines is directly electrically connected to the busbar doped region corresponding to the interconnection structures. In the first direction M, the positioning region 13 is designed to be located between adjacent first and second busbar doped regions, and in the case where the back contact battery piece also includes busbar lines, the busbar lines are located on the busbar doped regions, that is, the positioning region 13 is designed to be located between adjacent first and second busbar lines, which can effectively solve the positioning problem between the lines and the doped regions, and improve the positioning accuracy. Alternatively, in FIGS. 1-7, in the first direction M, the positioning region 13 can be located between adjacent first and second busbar doped regions, and the positioning region 13 can be a first current collecting doped region or a second current collecting doped region.

[0091] Optionally, referring to FIGS. 1-4, the positioning region 13 has the same polarity of the current collecting doped regions on both sides in the second direction Q, and the second direction Q has the second isolation region 17 on both sides of the positioning region, thereby achieving uniform collection of carriers on the whole surface, and achieving sufficient collection of carriers on both sides of the positioning region 13, and the positioning region 13 is located in the middle of one current collecting doped region, and the process compatibility is better. For example, referring to FIGS. 1-4, the positioning region 13 has the same polarity of the first current collecting doped regions on both sides in the second direction Q, and the second direction Q has the second isolation region 17 on both sides of the positioning region 13. The third isolation region 15 is arranged between the adjacent first current collecting doped region and the second current collecting doped region, the second isolation region 17 can partially coincide with the third isolation region 15, or the second isolation region 17 can coincide with the third isolation region 15 on one side, or the third isolation region 15 directly exists as the second isolation region 17, or the second isolation region 17 and the third isolation region 15 can be separated, and the above are not specifically limited.

[0092] Optionally, referring to FIG. 1, the positioning region 13 has the opposite polarity of the current collecting doped regions on both sides in the first direction M, that is, one side of the positioning region 13 has the first current collecting doped region, and the other side has the second current collecting doped region, or one side of the positioning region 13 has the N-type current collecting doped region, and the other side has the P-type current collecting doped region. In the first direction M, the opposite polarity of the current collecting doped regions has the first isolation region 14 on both sides of the positioning region 13, and the above first isolation region 14 limits the positioning region 13 to be a relatively independent region. For example, in FIG. 1, in the first direction M, the left side of the positioning region 13 has the first current collecting doped region 11, and the right side of the positioning region 13 has the second current collecting doped region 12, and the positioning region 13 has the first isolation region 14 between the left side and the first current collecting doped region 11, and the positioning region 13 has the first isolation region 14 between the right side and the second current collecting doped region 12. In the first direction M, the opposite polarity of the current collecting doped regions has the first current collecting doped region 11 on both sides of the positioning region 13, and referring to FIG. 1, the first current collecting gate line 21 is arranged on the first current collecting doped region 11, and the second current collecting gate line 22 is arranged on the second current collecting doped region 12, so that the opposite polarity of the current collecting gate lines has the first current collecting gate line 21 on both sides of the positioning region 13 in the first direction M, and the positioning region 13 is equivalent to a dead zone, which can solve the problem of poor carrier collection caused by the dead zone. In this case, the positioning region 13 can not be provided with the current collecting gate line.

[0093] Optionally, the first isolation region 14 here can be surrounded by the aforementioned second isolation region 17 to form a continuous isolation region, which is conducive to the accuracy of the camera's grabbing and positioning. Alternatively, the first isolation region 14 here and the aforementioned second isolation region 17 can not be surrounded to form a continuous isolation region, or in other words, the first isolation region 14 here and the aforementioned second isolation region 17 can have a spacing, which can improve the patterning capacity and reduce the cost.

[0094] Optionally, the bus doping region is only provided at at least one end of the battery body along the second direction Q, and in the second direction Q, the bus doping region and the positioning region 13 have a spacing, and the bus doping region in the middle region is removed, which reduces the light shielding area caused by the bus grid lines, while the end region retains the bus doping region, which can reserve space for the electrical interconnection of the back contact battery piece, reduce the welding difficulty, and the positioning region is arranged in the middle region, which is convenient for the camera to accurately position the positioning region.

[0095] Optionally, the bus doping region is provided at both end regions of the battery body along the second direction Q, and in the two end regions, the current collecting doping region and the bus doping region with the same polarity are electrically connected, and the bus doping region with the opposite polarity is electrically isolated. There is a middle region between the two end regions, and the middle region is provided with current collecting doping regions which are continuously distributed along the first direction and alternately distributed along the second direction, and the positioning region 13 is located in the middle region, and in the second direction Q, the bus doping region and the positioning region 13 have a spacing, and the bus doping region in the middle region is removed, which reduces the light shielding area caused by the bus grid lines, while the end region retains the bus doping region, which can reserve space for the electrical interconnection of the back contact battery piece, reduce the welding difficulty, and the positioning region 13 is arranged in the middle region, which is convenient for the camera to accurately position the positioning region 13.

[0096] It should be understood that, in this context, the extension of the bus doping region in the second direction Q can include the following cases: extending from one end of the battery body to the other end through the middle region along the second direction Q; or extending from one end of the battery body to the middle region along the second direction Q but not reaching the middle region, in which case the bus doping region is only provided at one end or both ends of the battery body along the second direction Q.

[0097] In the case where the busbar doped region extends from one end of the cell body to the other end through the intermediate region in the second direction Q, the positioning region 13 can be located between the adjacent first busbar doped region and the second busbar doped region, for example, various positions on the middle line in the second direction Q between the adjacent first busbar doped region and the second busbar doped region in the first direction M, for example, the middle position or the position closer to one end of the cell body. In the case where the back contact cell also includes busbar lines, the busbar lines are located on the busbar doped region, that is, the positioning region 13 is designed to be located between the adjacent first busbar line and the second busbar line, which can effectively solve the positioning problem between the busbar line and the doped region, and improve the positioning accuracy.

[0098] In the case where the busbar doped region extends from one end of the cell body to the intermediate region but does not reach the intermediate region in the second direction Q, when the busbar doped region is only provided at the two ends of the cell body in the second direction Q, the positioning region 13 can be in various positions. For example, the positioning region 13 can be located between the adjacent first busbar doped region and the second busbar doped region in the first direction M, for example, various positions on the middle line in the second direction Q between the adjacent first busbar doped region and the second busbar doped region in the first direction M, for example, the middle position or the position closer to one end of the cell body; when the positioning region 13 is at the middle position on the middle line, the busbar doped region of the intermediate region is removed, reducing the shading area caused by the busbar line, while the end region retains the busbar doped region, which can reserve the space for the electrical interconnection of the cell, reduce the welding difficulty, and the positioning region is arranged in the intermediate region, which is convenient for the camera to capture the positioning region for accurate positioning; when the positioning region 13 is at the position closer to one end of the cell body on the middle line, in the case where the back contact cell also includes busbar lines, the busbar lines are located on the busbar doped region, that is, the positioning region 13 is designed to be located between the adjacent first busbar line and the second busbar line, which can effectively solve the positioning problem between the busbar line and the doped region, and improve the positioning accuracy. It is also possible that the positioning region 13 can be located in the intermediate region between the first busbar doped region at the two ends of the cell body in the second direction Q and have a spacing with the first busbar doped region at the two ends in the second direction Q; or, be located in the intermediate region between the second busbar doped region at the two ends of the cell body in the second direction Q and have a spacing with the second busbar doped region at the two ends in the second direction Q, in which case, in the second direction Q, the busbar doped region has a spacing with the positioning region 13, the busbar doped region of the intermediate region is removed, reducing the shading area caused by the busbar line, while the end region retains the busbar doped region, which can reserve the space for the electrical interconnection of the cell, reduce the welding difficulty, and the positioning region is arranged in the intermediate region, which is convenient for the camera to capture the positioning region for accurate positioning.

[0099] In the case where the busbar doped regions extend from one end of the battery body to the middle region along the second direction Q but do not reach the middle region, when the busbar doped regions are only arranged at one end of the battery body along the second direction Q, the position of the positioning region can be suitably arranged according to the above two cases and the corresponding technical effects described above.

[0100] FIGS. 8a and 8b schematically show the schematic diagrams of the busbar doped regions in the embodiments of the present application. In FIG. 8a, the first busbar doped region 18 and the second busbar doped region 19 extend from one end of the battery body to the other end through the middle region along the second direction Q, and in the first direction M, the positioning region can be located between the adjacent first busbar doped region 18 and the second busbar doped region 19. In FIG. 8b, the first busbar doped region 18 and the second busbar doped region 19 extend from both ends of the battery body to the middle region but do not reach the middle region along the second direction Q, that is, the first busbar doped region 18 and the second busbar doped region 19 are only arranged at both ends of the battery body along the second direction Q, and there is a middle region between the two end regions, the middle region is provided with the current collecting doped regions 11 and 12 which are continuously distributed along the first direction M and alternately distributed along the second direction Q, and the positioning region can be located in the middle region, and in the second direction Q, the busbar doped regions and the positioning region can have a spacing.

[0101] Optionally, the shape of the positioning region 13 is not limited, and can be any convenient shape, including square, irregular polygon, irregular pattern with curved surface, etc., and in particular, for square, especially square or rectangular positioning region, it is easier to be grabbed by the alignment device, and the accuracy of alignment recognition is improved.

[0102] Optionally, referring to FIG. 1, the size of the positioning region 13 in the aforementioned first direction M is L1, the distance between the adjacent current collecting doped regions with opposite polarities in the aforementioned first direction M is L2, which is the distance between the end points of the adjacent current collecting doped regions with opposite polarities in the aforementioned first direction M, L2>L1>L2 / 2, and in particular, if L1 is too large, there is a risk of electric leakage, and if L1 is too small, the positioning effect is poor, therefore, L2>L1>L2 / 2 in the present application not only has a smaller risk of electric leakage but also has a better positioning effect.

[0103] For example, L1 can be 0.99L2, 0.97L2, 0.95L2, 0.9L2, 0.85L2, 0.8L2, 0.77L2, 0.7L2, 0.75L2, 0.65L2, 0.6L2, 0.55L2, 0.52L2, 0.51L2.

[0104] Optionally, referring to FIG. 2, the size of the positioning area 13 in the second direction Q is L3, the distance between two adjacent collecting-doped areas with the same polarity in the second direction Q is L4, L4>L3>L4 / 2, and in the embodiment of FIG. 2, the positioning area 13 has two collecting-doped areas with the same polarity on both sides in the second direction Q, and the two adjacent collecting-doped areas with the same polarity refer to two collecting-doped areas with different polarities that are adjacent to the positioning area 13 on both sides. Specifically, L3 is too large to break more fine grids and bring more dead zones, and L3 is too small to meet the positioning effect, and L4>L3>L4 / 2 meets the high positioning accuracy and brings fewer dead zones.

[0105] For example, L3 can be 0.99L4, 0.96L4, 0.95L4, 0.9L4, 0.85L4, 0.8L4, 0.78L4, 0.75L4, 0.7L4, 0.65L4, 0.6L4, 0.55L4, 0.52L4, 0.51L4.

[0106] Optionally, referring to FIGS. 1 to 4, in the second direction Q, the positioning area 13 has a second isolation area 17 adjacent to the collecting-doped area, so as to set the positioning area 13 as a relatively independent area in the second direction Q. The first collecting-doped area 11 and the second collecting-doped area 12 adjacent to each other are provided with a third isolation area 15 to avoid internal short circuit of the battery piece. Referring to FIG. 3, the size of the third isolation area 15 in the second direction Q is L5. The size of the first isolation area 14 on one side of the positioning area 13 in the first direction M is L6. 1.5×L5>L6>L5 is met, and L6 is appropriately set, which not only can achieve good isolation effect, but also avoids space waste.

[0107] For example, L6 can be 1.49L5, 1.4L5, 1.35L5, 1.3L5, 1.25L5, 1.2L5, 1.15L5, 1.1L5, 1.08L5, 1.05L5, 1.01L5.

[0108] Optionally, referring to FIG. 3, the size of the second isolation area 17 on one side of the positioning area 13 in the second direction Q is L7, and L5=L7, and L7 is appropriately set, which not only can achieve good isolation effect, but also avoids space waste.

[0109] Optionally, the positioning area 13 has the same polarity of the current collecting doped area on both sides in the first direction M, that is, the positioning area 13 has the first current collecting doped area on both sides in the first direction M, or the positioning area 13 has the second current collecting doped area on both sides in the first direction M. In the case that the first isolation area 14 is arranged on both sides of the positioning area 13, the positioning area 13 and the current collecting doped area with the same polarity are effectively distinguished by the first isolation area 14, which is beneficial to the alignment device to grab the positioning area and achieve effective alignment.

[0110] Optionally, the first isolation area 14 and the second isolation area 17 can be arranged to form a continuous isolation area, which is beneficial to the accuracy of the grabbing and positioning. Alternatively, the first isolation area 14 and the second isolation area 17 can not be arranged to form a continuous isolation area, or the first isolation area 14 and the second isolation area 17 can have a spacing, which can improve the patterning capacity and reduce the cost.

[0111] Optionally, referring to FIG. 4, the back contact battery piece further comprises a positioning electrode point 16, a normal projection of the positioning electrode point 16 on the battery body is located in the positioning area 13, and the size of the positioning electrode point 16 in the second direction Q is L8, the size of the positioning area 13 is L3, 0.4xL3

[0112] For example, L8 can be 0.41L3, 0.45L3, 0.5L3, 0.55L3, 0.58L3, 0.6L3, 0.61L3, 0.63L3, 0.65L3, 0.7L3, 0.75L3, 0.79L3.

[0113] Optionally, referring to FIG. 5, the positioning area 13 is distributed symmetrically about the symmetry axis parallel to the second direction Q in the back contact battery piece, and the connecting line of adjacent positioning areas 13 forms a rectangular or square positioning area. In the case of using laser to form the positioning area, the camera can be used for grabbing and positioning, and the electrode pattern design of the upper and lower half pieces can be compatible, which can reduce the complexity of mass production.

[0114] Optionally, referring to FIG. 1 to FIG. 4, the positioning area 13 is a first collecting doped area or a second collecting doped area. Referring to FIG. 5, one back contact cell has at least two positioning areas 13 which are collinear along the first direction M, all the positioning areas 13 collinear along the first direction M are first collecting doped areas or second collecting doped areas, the preparation process is simple, and the connecting line of the adjacent positioning areas 13 forms a rectangular or square positioning area, in the case of forming the positioning area by laser, the camera can be easily captured and positioned, and the electrode pattern design of the upper and lower half pieces can be compatible, so that the complexity of mass production can be reduced.

[0115] Optionally, the number of the positioning areas 13 is 2 to 4, the number of the positioning areas 13 is more appropriate, the positioning is more accurate, and more dead zones are not formed. That is, the number of the positioning areas 13 can be 2, 3 or 4.

[0116] Optionally, the area of one positioning area 13 is 0.5mm 2 to 1.5mm 2 , the area of the positioning area 13 is more appropriate, the positioning is more accurate, and more dead zones are not formed. For example, the area of one positioning area 13 can be 0.5mm 2 , 0.55mm 2 , 0.6mm 2 , 0.65mm 2 , 0.7mm 2 , 0.75mm 2 , 0.8mm 2 , 0.85mm 2 , 0.9mm 2 , 1.0mm 2 , 1.15mm 2 , 1.2mm 2 , 1.5mm 2 .

[0117] Optionally, the positioning region 13 is a P-type collecting doped region, which has stronger compatibility with the existing process of the back contact cell. It should be noted that in the back contact cell, the positioning region 13 is the collecting doped region of the type which is prepared first. For example, in the back contact cell, the N-type collecting doped region is prepared first, and the positioning region 13 is the N-type collecting doped region. For another example, in the back contact cell, the P-type collecting doped region is prepared first, and the positioning region 13 is the P-type collecting doped region. The positioning region has the same layer structure, size, crystallization rate or roughness as the P-type collecting doped region or the N-type collecting doped region, i.e. the positioning region will not cause damage to the collecting doped region in the process of forming the positioning region. For example, the positioning region and the P-type collecting doped region have the same layer structure, and along the direction away from the cell body, the positioning region is provided with a tunneling passivation layer, a P-type doped polysilicon, a passivation anti-reflection layer and a metal electrode at the corresponding position, wherein the size, crystallization rate and roughness of the P-type doped polysilicon of the positioning region are the same as those of the P-type collecting doped region; or along the direction away from the cell body, the positioning region is provided with an intrinsic interface passivation layer, a P-type doped amorphous silicon, a TCO and a metal electrode at the corresponding position, wherein the size, crystallization rate and roughness of the P-type doped amorphous silicon of the positioning region are the same as those of the P-type collecting doped region. The present application is not limited thereto, and the appropriate layer structure, size, crystallization rate or roughness can be selected according to actual needs.

[0118] Optionally, referring to FIG. 1 and FIG. 2, the back contact cell further comprises a first collecting grid line 21 located on the first collecting doped region and a second collecting grid line 22 located on the second collecting doped region. The first collecting grid line 21 and the second collecting grid line 22 located on both sides of the positioning region 13 have a spacing with the positioning region 13, which can reduce the risk of short circuit. Here, the first collecting grid line 21 is an N-type collecting grid line when the first collecting doped region is an N-type collecting doped region, and the first collecting grid line 21 is a P-type collecting grid line when the first collecting doped region is a P-type collecting doped region.

[0119] Optionally, referring to FIG. 1 and FIG. 2, the back contact cell further comprises: a first current collecting grid line 21 on the first current collecting doped region, a second current collecting grid line 22 on the second current collecting doped region, a first bus bar grid line on the first bus bar doped region, and a second bus bar grid line on the second bus bar doped region. At least part of the first current collecting grid line 21 and the first bus bar grid line intersect, and at least part of the second current collecting grid line 22 and the second bus bar grid line intersect, so that current collection is conveniently achieved through the current collecting grid line and the bus bar grid line. Here, in the case that the first current collecting doped region is an N-type current collecting doped region, the first current collecting grid line 21 is an N-type current collecting grid line, the first bus bar doped region is an N-type bus bar doped region, and the first bus bar grid line is an N-type bus bar grid line. Here, in the case that the first current collecting doped region is a P-type current collecting doped region, the first current collecting grid line 21 is a P-type current collecting grid line, the first bus bar doped region is a P-type bus bar doped region, and the first bus bar grid line is a P-type bus bar grid line.

[0120] Optionally, referring to FIG. 5, the back contact cell further comprises: a plurality of electrode pads on the bus bar grid line, which can exist as welding points in the process of forming a cell string. The plurality of electrode pads comprise: at least two positioning electrode pads 23 corresponding to the positioning region and away from the geometric center of the back contact cell, the shape of the positioning electrode pad 23 is different from that of the remaining electrode pads 24, and the at least two positioning electrode pads 23 are distributed in the back contact cell in axial symmetry about the axis of symmetry parallel to the second direction Q, so that the connecting line of adjacent positioning electrode pads 23 can form a rectangular or square second positioning region. In the case of forming the positioning region by laser, the camera can be facilitated to capture positioning, and the electrode pattern design at different positions in the whole back contact cell can reduce the complexity of mass production. After the positioning electrode pad 23 is formed, it can exist as a positioning point in the subsequent process, which can further improve the positioning accuracy.

[0121] Optionally, the back contact cell further comprises: insulating glue, which is located at least on the current collecting grid line adjacent to the bus bar grid line to avoid short circuit. The orthographic projection of the insulating glue on the cell body is separated from the positioning region 13, so as to avoid that the insulating glue shields the positioning region 13.

[0122] Optionally, the positioning region 13 has the same polarity of the current collecting doped regions on both sides in the first direction M, that is, the positioning region 13 has the first current collecting doped region on both sides in the first direction M, or the positioning region 13 has the second current collecting doped region on both sides in the first direction M. A current collecting grid line extends from one side of the positioning region 13 to the other side of the positioning region 13, and is continuously distributed on the current collecting doped regions with the same polarity in the first direction. Here, the current collecting grid line can be continuously arranged, and the first isolation region does not form a dead zone. The current collecting efficiency is higher when the continuous current collecting grid line is used for current collection between adjacent bus grid lines.

[0123] The application also provides another back contact cell, comprising: a cell body; the cell body comprising: a plurality of cell units and a division area between adjacent cell units, the cell unit comprising: a current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first current collecting doped region and the second current collecting doped region extending along a first direction and alternately and spacedly distributed along a second direction; the first direction being different from the second direction; the first current collecting doped region and the second current collecting doped region being different in doped type; a busbar doped region, comprising a first busbar doped region and a second busbar doped region, the first busbar doped region and the second busbar doped region extending along the second direction and alternately and spacedly distributed along the first direction; the first busbar doped region and the second busbar doped region being different in doped type; the first current collecting doped region and the first busbar doped region being the same in polarity, and the second current collecting doped region and the second busbar doped region being the same in polarity; at least part of the first current collecting doped region and the first busbar doped region intersecting, and at least part of the second current collecting doped region and the second busbar doped region intersecting; a positioning region, the positioning region having, on both sides in the first direction, a current collecting doped region of at least one polarity, the current collecting doped region of the at least one polarity having, in the first direction, a first isolation region on at least one side of the positioning region, and the positioning region having, on both sides in the second direction, a current collecting doped region of at least one polarity, the current collecting doped region of the at least one polarity having, in the second direction, a second isolation region on both sides of the positioning region. In the back contact cell, all the positioning regions are symmetric about the center of the cell body thereof. Here, the cell body, the current collecting doped region, the first current collecting doped region, the second current collecting doped region, the busbar doped region, the first busbar doped region, the second busbar doped region, the positioning region, the first isolation region, the first direction and the second direction can correspond to the cell body, the current collecting doped region, the first current collecting doped region, the second current collecting doped region, the busbar doped region, the first busbar doped region, the second busbar doped region, the positioning region, the first isolation region, the first direction and the second direction in the aforementioned back contact cell, and will not be repeated here to avoid repetition.

[0124] Optionally, the positioning area 13 passes the middle line between the adjacent first and second confluence doped areas, and the middle line is parallel to the second direction, so that the line of four adjacent positioning areas 13 in the back contact cell forms a rectangular or square positioning area. In the case of forming the positioning area by laser, the requirement for the distance from the alignment light source can be reduced, more patterning light sources can be compatible, and uniform collection of PN zone carriers can be achieved. Moreover, in the back contact cell, the positioning area 13 is located at a position conducive to forming a centrosymmetric back contact cell, which reduces the difficulty of interconnection alignment and is easy to operate during the electrical connection process of the back contact cell obtained after slicing.

[0125] Optionally, the back contact cell is sliced along the segmentation area to obtain any of the aforementioned back contact cells, and the one cell before slicing corresponds to any of the aforementioned back contact cells after slicing. The segmentation area can extend along the first direction M, that is, the back contact cell is a whole cell before slicing. A back contact cell includes several cell units, and several back contact cells are usually obtained after slicing, and the number of back contact cells obtained after slicing is not limited.

[0126] The back contact cell has the same or similar beneficial effects as any of the aforementioned back contact cells, and will not be described here to avoid repetition.

[0127] The application also provides a preparation method of a back contact cell, including the following steps.

[0128] Step 101, providing a silicon substrate; the silicon substrate includes a first surface and a second surface opposite to each other.

[0129] The crystal type and the doping type of the silicon substrate are not limited. During normal operation of the back contact cell, the surface of the silicon substrate mainly receiving light is the light-receiving surface, that is, the second surface, and the back surface of the silicon substrate, that is, the first surface, is opposite to the light-receiving surface.

[0130] Step 102, forming a first doped layer on the first surface of the silicon substrate.

[0131] That is, a whole first doped layer is formed on the first surface of the silicon substrate, and the forming method is not limited.

[0132] Step 103, removing part of the first doped layer so that part of the first surface is exposed, and the remaining first doped layer forms a plurality of first current collecting doped regions extending along a first direction and spaced along a second direction, and a plurality of first busbar doped regions extending along the second direction and spaced along the first direction; at least part of the first current collecting doped regions and the first busbar doped regions intersect; part of the plurality of first current collecting doped regions covers a positioning region, and the first doped layer around the positioning region is removed. Wherein, the first direction is different from the second direction.

[0133] Referring to FIG. 6, the part with shading in FIG. 6 is the exposed part of the first surface of the silicon substrate 1, that is, the part with shading in FIG. 6 is the part where the first doped layer is removed, and the white part is the remaining first doped layer, which includes a plurality of first current collecting doped regions extending along a first direction M and spaced along a second direction Q, and a plurality of first busbar doped regions extending along the second direction Q and spaced along the first direction M. At least part of the first current collecting doped regions and the first busbar doped regions intersect, and after removing part of the first doped layer, the exposed first surface is the place where the second current collecting doped regions and the second busbar doped regions are to be formed subsequently. For example, in FIG. 6, the shaded part enclosed by the left dashed line is the position where the second current collecting doped regions and the second busbar doped regions are to be formed subsequently and the subsequent isolation region, and the isolation region here includes a first isolation region, a second isolation region and a third isolation region.

[0134] Optionally, a first laser method can be used to remove part of the first doped layer, and the laser in the first laser method loosens part of the first doped layer, and then the loosened part of the first doped layer is removed by cleaning. The laser method is easy to remove part of the first doped layer.

[0135] Part of the plurality of first current collecting doped regions covers a positioning region 13, and the first doped layer around the positioning region 13 is removed, that is, the square blank area R in the middle in FIG. 6 is the position where the positioning region 13 is to be formed subsequently. The first doped layer can be an N-type doped layer or a P-type doped layer, which is not limited in particular. When the first doped layer is an N-type doped layer, the first current collecting doped regions are N-type current collecting doped regions, and the first busbar doped regions are N-type busbar doped regions. When the first doped layer is a P-type doped layer, the first current collecting doped regions are P-type current collecting doped regions, and the first busbar doped regions are P-type busbar doped regions.

[0136] Step 104, forming a second doped layer on the exposed first surface and the remaining first doped layer; the first doped layer and the second doped layer are different in doping type.

[0137] This step is to form a second doped layer on the back of the silicon substrate based on step 103. If the first doped layer is an N-type doped layer, then the second doped layer is a P-type doped layer. If the first doped layer is a P-type doped layer, then the second doped layer is an N-type doped layer.

[0138] Step 105, remove part of the second doped layer, so that the first and second current collecting doped regions and the first and second bus doped regions are exposed, forming the first and second current collecting doped regions extending along the first direction and alternatingly spaced along the second direction, the first and second bus doped regions extending along the second direction and alternatingly spaced along the first direction, and the positioning region. At least part of the first and second current collecting doped regions and the first and second bus doped regions intersect. The positioning region has at least one type of current collecting doped region on both sides in the first direction, and at least one side of the positioning region has a first isolation region in the first direction. The positioning region has at least one type of current collecting doped region on both sides in the second direction, and both sides of the positioning region have a second isolation region in the second direction.

[0139] The first current collecting doped region is one of an N-type current collecting doped region and a P-type current collecting doped region, and the second current collecting doped region is the other of the N-type current collecting doped region and the P-type current collecting doped region. The first bus doped region is one of an N-type bus doped region and a P-type bus doped region, and the second bus doped region is the other of the N-type bus doped region and the P-type bus doped region. The first current collecting doped region and the first bus doped region have the same polarity or the same doping type, and the second current collecting doped region and the second bus doped region have the same polarity or the same doping type.

[0140] Referring to FIG. 7, step 105 is to remove part of the second doped layer, so that the first and second current collecting doped regions and the first and second bus doped regions are exposed, and the second doped layer in the isolation region is removed to form the isolation region, which includes the first isolation region, the second isolation region, and the third isolation region, and forms the first and second current collecting doped regions extending along the first direction and alternatingly spaced along the second direction, the first and second bus doped regions extending along the second direction and alternatingly spaced along the first direction, and the positioning region. At least part of the first and second current collecting doped regions and the first and second bus doped regions intersect. It should be noted that the boxes in FIGS. 6 and 7 are only for the convenience of illustrating different regions, and are not actually present in the back contact solar cell.

[0141] Optionally, the part of the first doped layer and the part of the second doped layer are partially overlapped, so that at least part of the positioning area is exposed silicon substrate, and the exposed silicon substrate forms the first isolation region and the second isolation region, which can be formed by a process compatible with the related process in the existing process, and the process is simple and the positioning area is easy to be grabbed.

[0142] Optionally, the part of the second doped layer can be loosened by the laser in the second laser mode, and then the loosened part of the second doped layer is cleaned to remove the part of the second doped layer. The laser mode can form the positioning area compatible with the two laser modes in the existing process, and the process is simple.

[0143] Optionally, the part of the first doped layer includes a first laser area in the shape of a photo frame, and the part of the second doped layer includes a second laser area in the shape of a square, wherein the second laser area covers the inner frame of the first laser area and extends to cover part of the photo frame, thereby forming the first isolation region and the second isolation region. The above method can be compatible with the existing process flow of the back contact cell, and no special process is required for the positioning area, while ensuring that the height of the positioning area is not too high to affect the printing quality of the grid lines.

[0144] Optionally, the method can further include: multiple grid line preparation, wherein the positioning area 13 can be used as a positioning point to perform the first grid line preparation and form a positioning electrode point 16 in the positioning area 13. Then, the positioning electrode point 16 can be used as a positioning point to perform the preparation of the remaining grid lines, so that the back contact cell grid lines and the corresponding doped area can be accurately aligned, and the current collection effect is more effective.

[0145] It should be noted that the preparation method of the back contact cell is used to prepare any of the aforementioned back contact cells, and the relevant parts can be referred to each other. In order to avoid repetition, the details are not described here.

[0146] The application also provides a photovoltaic module, which includes: a plurality of any of the aforementioned back contact cells, and other structures of the photovoltaic module are not specifically limited, for example, the photovoltaic module can further include encapsulating adhesive films located on opposite sides of the back contact cells, and the like, which are not specifically limited.

[0147] The application also provides a photovoltaic module, which includes:

[0148] A plurality of back contact cell pieces; the back contact cell piece comprises: a cell body, the cell body comprises: a current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first current collecting doped region and the second current collecting doped region extend along a first direction and are alternately and spacedly distributed along a second direction; the first direction is different from the second direction; the first current collecting doped region and the second current collecting doped region are different in doped type, one of which is an N-type current collecting doped region and the other is a P-type current collecting doped region;

[0149] The back contact cell piece further comprises: a current collecting grid line on the cell body, the current collecting grid line comprises a first current collecting grid line on the first current collecting doped region and a second current collecting grid line on the second current collecting doped region;

[0150] An interconnecting piece, the interconnecting piece electrically connects two adjacent back contact cell pieces, one end of the interconnecting piece is electrically connected with the second current collecting grid line of one of the two adjacent back contact cell pieces, and the other end of the interconnecting piece is electrically connected with the first current collecting grid line of the other of the two adjacent back contact cell pieces;

[0151] The cell body further comprises:

[0152] A positioning region, the positioning region has a current collecting doped region of at least one polarity on both sides in the first direction, and the current collecting doped region of the at least one polarity has a first isolation region on at least one side of the positioning region in the first direction; the positioning region has a current collecting doped region of at least one polarity on both sides in the second direction, and the current collecting doped region of the at least one polarity has a second isolation region on both sides of the positioning region in the second direction.

[0153] Optionally, in the first direction, the positioning region is located between adjacent interconnecting pieces.

[0154] Optionally, the back contact cell piece included in the photovoltaic module and the cell piece in other embodiments of the application are basically the same, the difference is that the back contact cell piece in the embodiment can not have a busbar doped region and can not have a busbar grid line, the busbar grid line is replaced by an interconnecting piece, and the interconnecting piece and the current collecting grid line are electrically connected, thereby saving metal paste and reducing the recombination caused by the metal paste and improving the output power of the photovoltaic module.

[0155] Optionally, the interconnecting piece can be a solder strip or a conductive back plate with an interconnecting piece function, the conductive back plate can simplify the cell interconnection piece arrangement process and reduce the repair difficulty.

[0156] The photovoltaic module has the same or similar beneficial effects as any of the aforementioned back contact cell pieces, and the related parts can be referred to each other, and to avoid repetition, this will not be repeated here.

[0157] The application will be further explained in connection with specific embodiments.

[0158] Embodiment 1

[0159] In the first step, an N-type silicon substrate is provided. The N-type silicon substrate includes opposite first and second surfaces.

[0160] In the second step, borosilicate glass (BSG) is formed on the first surface of the N-type silicon substrate to form a P-type doped layer.

[0161] In the third step, a first laser method is used to remove part of the P-type doped layer, so that part of the first surface of the N-type silicon substrate is exposed. The remaining P-type doped layer includes a plurality of P-type collector doped regions extending along the first direction M and spaced apart along the second direction Q, and a plurality of P-type bus doped regions extending along the second direction Q and spaced apart along the first direction M. Part of the plurality of P-type collector doped regions covers the positioning region, and the P-type doped layer around the positioning region is removed.

[0162] In the fourth step, an N-type doped layer is formed on the exposed first surface and the remaining P-type doped layer.

[0163] In the fifth step, a second laser method is used to remove part of the N-type doped layer, so that the plurality of P-type collector doped regions and the plurality of P-type bus doped regions formed in the third step are exposed. A plurality of P-type collector doped regions and a plurality of N-type collector doped regions extending along the first direction and alternately spaced apart along the second direction, a plurality of P-type bus doped regions and a plurality of N-type bus doped regions extending along the second direction and alternately spaced apart along the first direction, and the positioning region are formed. At least part of the P-type collector doped regions and the P-type bus doped regions intersect, and at least part of the N-type collector doped regions and the N-type bus doped regions intersect. The N-type doped layer around the positioning region is removed to form an isolation region. In the first direction, the positioning region is located between adjacent N-type bus doped regions and P-type bus doped regions. Referring to FIG. 1, the positioning region has collector doped regions with opposite polarities on both sides in the first direction. In the first direction, the collector doped regions with opposite polarities and the positioning region have a first isolation region 14. In the second direction, the positioning region 13 has N-type collector doped regions 11 with the same polarity on both sides, and the N-type collector doped regions 11 with the same polarity on both sides of the positioning region 13 have a second isolation region on both sides in the second direction. The first isolation region and the second isolation region form a continuous isolation region.

[0164] The fifth step forms four positioning areas. Taking the position corresponding to the geometric center of the silicon substrate as the coordinate origin, the coordinate positions of the geometric centers of the four positioning areas are (-61.63 63.78), (61.63 63.78), (-61.63-63.78), and (61.63 63.78), respectively. The area of one positioning area is 1 mm 2 .

[0165] In the sixth step, in the process of forming the back contact cell, the gate line is printed three times. The first gate line printing is performed, and the positioning electrode point 16 is printed in the positioning area. The subsequent printing is performed by taking the positioning electrode point 16 as the positioning point. In the subsequent printing process of the insulating glue, the positioning electrode point 16 can also be taken as the positioning point. The positioning accuracy can be improved by the positioning area 13 and the positioning electrode point 16.

[0166] The back contact cell is sliced along a direction parallel to the first direction to obtain two half back contact cells.

[0167] Example 2

[0168] The main difference between Example 2 and Example 1 is that the area of one positioning area in Example 2 is 0.8 mm 2 , and the remaining part can refer to the preceding Example 1.

[0169] Example 3

[0170] The main difference between Example 3 and Example 1 is that in Example 3, the positioning area has a current collecting doped area only on one side in the first direction, and the remaining part can refer to the preceding Example 1.

[0171] Comparative Example 1

[0172] The main difference between Comparative Example 1 and Example 1 is that the area of one positioning area in Comparative Example 1 is 0.3 mm 2 , and the remaining part can refer to the preceding Example 1.

[0173] Comparative Example 2

[0174] Comparative Example 2 uses edge positioning in the related art to position.

[0175] Comparative Example 3

[0176] Comparative Example 3 uses cross positioning or original shape positioning in the related art to position.

[0177] Comparative Example 4

[0178] The main difference between Comparative Example 4 and Example 1 is that in Comparative Example 4, the positioning region is not provided with the current collecting doped regions on both sides in the first direction, and the rest can refer to the foregoing Example 1.

[0179] The sizes of the back contact battery pieces obtained in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 are equal. Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 all obtain 100,000 back contact battery pieces. The back contact battery pieces obtained in Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4 are tested for performance under the same test conditions.

[0180] In FIG. 9, the edge positioning corresponds to Comparative Example 2, the one-time positioning corresponds to Comparative Example 3, and the two-time positioning corresponds to Example 1. The average value of the positioning accuracy of the back contact battery pieces of Comparative Example 2, Comparative Example 3 and Example 1 is obtained by testing under the same test conditions. It can be seen from FIG. 9 that the positioning accuracy of the 100,000 back contact battery pieces obtained in Example 1 provided by the present application reaches 100%, which is significantly higher than the positioning accuracy of Comparative Example 2 and Comparative Example 3.

[0181] In FIG. 10, the vertical axis represents short-circuit current, and the unit is mA (milliampere). In FIG. 10, connection 1 corresponds to Comparative Example 4, connection 2 corresponds to Example 3, and connection 3 corresponds to Example 1. The average value of the short-circuit current of the back contact battery pieces of Comparative Example 4, Example 3 and Example 1 is obtained by testing under the same test conditions. It can be seen from FIG. 10 that the average value of the short-circuit current of the back contact battery pieces of Example 1 provided by the present application reaches 14.811 mA, which indicates that by providing the current collecting doped regions with opposite polarities on both sides of the positioning region in the first direction, the current can be effectively improved, and the problem of current collection caused by a large dead zone of the positioning region can be avoided. It can be seen from FIG. 10 that the average value of the short-circuit current of the back contact battery pieces of Example 3 provided by the present application reaches 14.808 mA, which indicates that by providing the current collecting doped region only on one side of the positioning region in the first direction, the current can be effectively improved, and the problem of current collection caused by a large dead zone of the positioning region can be avoided.

[0182] The vertical axis in FIG. 11 refers to short-circuit current, in mA. In FIG. 11, area 1 corresponds to one back contact cell in Example 1, area 2 corresponds to one back contact cell in Example 2, and area 3 corresponds to one back contact cell in Comparative Example 1. Under the same test conditions, the short-circuit current of the back contact cells in Example 1, Example 2 and Comparative Example 1 is tested, and it can be seen from FIG. 11 that the short-circuit current of the back contact cell in Example 1 provided by the application reaches 14.803 mA, and the short-circuit current of the back contact cell in Example 2 reaches 14.812 mA, which is significantly higher than that of Comparative Example 1, indicating that in the application, the area of the positioning area is more appropriate, not only accurate in positioning, but also conducive to effective collection of current, and the dead zone is smaller.

[0183] In summary, the positioning area in the application has at least one current collecting doped region of one polarity on both sides in the first direction, which can solve the problem of poor carrier collection caused by the dead zone. At the same time, the positioning area has a first isolation region and a second isolation region on both sides in the first direction and the second direction, which can isolate the positioning area and further improve the positioning accuracy. In addition, through the design concept of twice positioning, the positioning area is designed to be located between the adjacent first and second busbar doped regions, which can effectively solve the interference of the busbar grid line on the positioning effect. In addition, the area size of the positioning area, the related dimensions of the positioning area and the number of the positioning area are specified, which achieves good positioning effect and good current collection effect, and has less risk of short circuit. In addition, the busbar doped region is only arranged at the end of the cell body, and the busbar doped region in the middle region is removed, which can reduce the shading area caused by the busbar grid line, reserve space for cell electrical interconnection, reduce the welding difficulty, and the positioning area arranged in the middle region can facilitate the camera to capture the accurate positioning of the positioning area.

[0184] It should be noted that in this document, the terms "comprise", "comprise", or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or further include elements inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprises a" does not exclude the presence of additional identical elements in the process, method, article or device including the element.

[0185] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the specific embodiments described above, and the specific embodiments described above are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.

Claims

1. A back contact cell comprising: Battery body; The battery body comprises: A current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first current collecting doped region and the second current collecting doped region extend along a first direction and are alternately spaced along a second direction; the first direction is different from the second direction; the first current collecting doped region and the second current collecting doped region are different in doping type; A current collecting doped region, comprising a first current collecting doped region and a second current collecting doped region, the first current collecting doped region and the second current collecting doped region extend along a first direction and are alternately spaced along a second direction; the first direction is different from the second direction; the first current collecting doped region and the second current collecting doped region are different in doping type; A positioning region, the positioning region has the current collecting doped region of at least one polarity on both sides in the first direction, and the current collecting doped region of the at least one polarity has a first isolation region on at least one side of the positioning region in the first direction; the positioning region has the current collecting doped region of at least one polarity on both sides in the second direction, and the current collecting doped region of the at least one polarity has a second isolation region on both sides of the positioning region in the second direction.

2. The back contact cell as defined in claim 1, wherein The first current collecting doped region and the second current collecting doped region are only arranged at at least one end of the battery body along the second direction, and in the second direction, the first current collecting doped region and the second current collecting doped region have a spacing with the positioning region.

3. The back contact cell of claim 1, wherein, In the first direction, the positioning region is located between the adjacent first current collecting doped region and the second current collecting doped region.

4. The back contact cell of claim 3, wherein, The positioning region has the current collecting doped regions of opposite polarity on both sides in the first direction, and the current collecting doped regions of the opposite polarity have a first isolation region on both sides of the positioning region in the first direction, and the first isolation region and the second isolation region form a continuous isolation region.

5. The back contact cell according to claim 4, further comprising: In the current collecting doped regions of the opposite polarity in the first direction, a first current collecting grid line on the first current collecting doped region, and a second current collecting grid line on the second current collecting doped region, the first current collecting grid line and the second current collecting grid line on both sides of the positioning region in the first direction have a spacing with the positioning region.

6. The back contact cell of claim 4, wherein, The size of the positioning region in the first direction is L1, the distance between the current collecting doped regions of the opposite polarity in the first direction is L2; L2>L1>L2 / 2; and / or, A size of the positioning region in the second direction is L3, a distance between two adjacent collecting-doped regions with the same polarity in the second direction is L4; L4>L3>L4 / 2.

7. The back contact cell of claim 3, wherein, A third isolation region is arranged between the first and second collecting-doped regions; A size of the third isolation region in the second direction is L5; A size of the first isolation region in the first direction on one side of the positioning region is L6; A size of the second isolation region in the second direction on one side of the positioning region is L7; 1.5×L5>L6>L5; and / or, L5=L7.

8. The back contact cell of claim 3, further comprising: A positioning electrode point, a normal projection of which on the battery body is located in the positioning region; In the second direction: a size of the positioning electrode point is L8, and a size of the positioning region is L3; 0.4×L3 9. The back contact cell of claim 3, wherein, The positioning region has the collecting-doped regions with the same polarity on both sides in the first direction; the first isolation region is arranged on both sides of the positioning region in the first direction with respect to the collecting-doped regions with the same polarity; and the first and second isolation regions form a continuous isolation region.

10. The back contact cell sheet according to claim 9, further comprising: In the collecting-doped regions with the same polarity in the first direction, at least one of the first collecting grid lines on the first collecting-doped region or the second collecting grid lines on the second collecting-doped region extends from one side of the positioning region to the other side of the positioning region and is continuously distributed on the collecting-doped regions with the same polarity in the first direction.

11. The back contact cell of claim 3, wherein, The positioning region has the collecting-doped regions with the same polarity on both sides in the second direction; and the second isolation region is arranged on both sides of the positioning region in the second direction with respect to the collecting-doped regions with the same polarity.

12. The back contact cell of claim 3, wherein, The positioning region is axially symmetrically distributed in the back contact cell sheet with respect to a symmetry axis parallel to the second direction.

13. The back contact cell of claim 3, wherein, The positioning region is one of the first and second collecting-doped regions; The back contact cell sheet has at least two positioning regions collinear in the first direction; all the positioning regions collinear in the first direction are the first collecting-doped regions or the second collecting-doped regions.

14. The back contact cell of claim 3, wherein, The number of the positioning regions is 2-4; or One of said positioning areas has an area of 0.5 mm 2 up to 1.5 mm 2 .

15. The back contact cell according to any one of claims 3 to 14, wherein, The positioning region is a P-type collecting-doped region.

16. The back contact cell sheet according to claim 5 or 10, further comprising: A first busbar grid line on the first busbar-doped region and a second busbar grid line on the second busbar-doped region; At least part of the first collecting grid line intersects the first busbar grid line, and at least part of the second collecting grid line intersects the second busbar grid line.

17. The back contact cell sheet according to claim 16, further comprising: a plurality of electrode disks on the busbar grid lines; the plurality of electrode disks include: at least two positioning electrode disks corresponding to the positioning area and away from the geometric center of the back contact cell piece; the shape of the positioning electrode disk is different from the shape of the rest of the plurality of electrode disks; at least two positioning electrode disks are distributed on the back contact cell piece about an axis of symmetry parallel to the second direction.

18. The back contact cell of claim 16, further comprising: insulating glue; the insulating glue is located at least on the opposite current collecting grid lines adjacent to the busbar grid lines; the orthographic projection of the insulating glue on the battery body is separated from the positioning area.

19. A back contact cell comprising: a battery body; the battery body includes: a plurality of battery cells and a division area between adjacent battery cells, the battery cell includes: a current collecting doped area, including a first current collecting doped area and a second current collecting doped area, the first current collecting doped area and the second current collecting doped area extend along a first direction and are alternately and spacedly distributed along a second direction; the first direction is different from the second direction; the first current collecting doped area and the second current collecting doped area are different in doping type; a busbar doped area, including a first busbar doped area and a second busbar doped area, the first busbar doped area and the second busbar doped area extend along the second direction and are alternately and spacedly distributed along the first direction; the first busbar doped area and the second busbar doped area are different in doping type; the first current collecting doped area and the first busbar doped area are of the same polarity, and the second current collecting doped area and the second busbar doped area are of the same polarity; at least part of the first current collecting doped area and the first busbar doped area intersect, and at least part of the second current collecting doped area and the second busbar doped area intersect; a positioning area, the positioning area has the current collecting doped area of at least one polarity on both sides in the first direction, and at least one side of the positioning area has a first isolation area in the first direction; the positioning area has the current collecting doped area of at least one polarity on both sides in the second direction, and both sides of the positioning area have a second isolation area in the second direction; all the positioning areas of the plurality of battery cells are symmetric about the center of the battery body.

20. The back contact cell of claim 19, wherein, in the first direction, the positioning area is located between the adjacent first busbar doped area and the second busbar doped area.

21. The back contact cell of claim 20, wherein, the positioning area passes through the middle line between the adjacent first busbar doped area and the second busbar doped area.

22. The back contact cell according to claim 20 or 21, wherein, slicing the back contact cell piece along the division area to obtain a plurality of back contact cell pieces according to any one of claims 1 to 18.

23. A preparation method of a back contact cell piece, comprising: providing a silicon substrate; the silicon substrate includes opposite first and second surfaces; forming a first doped layer on the first surface of the silicon substrate; The first doped layer is removed in part, so that the first surface is exposed in part, and the remaining first doped layer comprises: a plurality of first current collecting doped regions extending in a first direction and spaced apart in a second direction, and a plurality of first busbar doped regions extending in the second direction and spaced apart in the first direction; at least part of the first current collecting doped regions and the first busbar doped regions intersect; part of the plurality of first current collecting doped regions covers a positioning region, and the first doped layer around the positioning region is removed; A second doped layer is formed on the exposed first surface and the remaining first doped layer; the first doped layer and the second doped layer are different in doping type; The second doped layer is removed in part, so that the plurality of first current collecting doped regions and the plurality of first busbar doped regions are exposed, forming first current collecting doped regions and second current collecting doped regions extending in the first direction and alternately spaced apart in the second direction, first busbar doped regions and second busbar doped regions extending in the second direction and alternately spaced apart in the first direction, and the positioning region; at least part of the second current collecting doped regions and the second busbar doped regions intersect; The positioning region has at least one polarity of the current collecting doped regions on both sides in the first direction, and at least one side of the positioning region has a first isolation region in the first direction; the positioning region has at least one polarity of the current collecting doped regions on both sides in the second direction, and both sides of the positioning region have a second isolation region in the second direction.

24. The method of producing a back contact cell as claimed in claim 23, wherein, In the first direction, the positioning region is located between adjacent first busbar doped regions and second busbar doped regions.

25. The method of producing a back contact cell as claimed in claim 24, wherein, The method further comprises: multiple gate line preparation, wherein, The first gate line preparation is performed with the positioning region as a positioning point, and a positioning electrode point is formed in the positioning region; The remaining gate line preparation is performed with the positioning electrode point as a positioning point.

26. The method of producing a back contact cell according to claim 24 or 25, wherein The part of the first doped layer removed and the part of the second doped layer removed partially overlap, so that at least part of the positioning region around the silicon substrate is exposed; the exposed silicon substrate forms the first isolation region and the second isolation region.

27. A photovoltaic module comprising: A plurality of back contact cell pieces according to any one of claims 1 to 18.

28. A photovoltaic module, comprising: A plurality of back contact cell pieces; The back contact cell piece comprises: a cell body, the cell body comprising: current collecting doped regions, comprising first current collecting doped regions and second current collecting doped regions, the first current collecting doped regions and the second current collecting doped regions extending in a first direction and alternately spaced apart in a second direction; the first direction is different from the second direction; the first current collecting doped regions and the second current collecting doped regions are different in doping type; The back contact cell piece further comprises: a current collecting grid line on the cell body, the current collecting grid line comprising a first current collecting grid line on the first current collecting doped region, and a second current collecting grid line on the second current collecting doped region; An interconnect electrically connects two adjacent back contact cell pieces, one end of the interconnect is electrically connected to the second current collecting grid line of one of the two adjacent back contact cell pieces, and the other end of the interconnect is electrically connected to the first current collecting grid line of the other of the two adjacent back contact cell pieces; The cell body further comprises: A positioning region, the positioning region has the current collecting doped region of at least one polarity on both sides in the first direction, and the current collecting doped region of the at least one polarity has a first isolation region on at least one side of the positioning region in the first direction; the positioning region has the current collecting doped region of at least one polarity on both sides in the second direction, and the current collecting doped region of the at least one polarity has a second isolation region on both sides of the positioning region in the second direction.

29. The photovoltaic module of claim 28, wherein, In the first direction, the positioning region is located between adjacent interconnects.

Images