Back contact battery

Abstract

The invention provides a back contact battery. The back contact battery comprises a substrate; the doped region is formed on the back surface of the substrate and comprises more than two first type doped units and more than two second type doped regions; the passivation layer is formed on the back surface of the substrate and covers the doping region, a first contact hole is formed in a first region, corresponding to each first type doping unit, of the passivation layer, and a second contact hole is formed in a second region, corresponding to each second type doping unit, of the passivation layer; the first electrode and the second electrode are formed on the insulating layer, the first electrode forms ohmic contact with the first type doping unit through the first contact hole, the second electrode forms ohmic contact with the second type doping unit through the second contact hole, the first electrode spans at least part of the second type doping unit and is isolated from the second type doping unit through the insulating layer, and / or the second electrode spans at least part of the second type doping unit. The second electrode spans at least part of the first type doping unit and is isolated from the first type doping unit through insulation. According to the invention, the shape of the doped region of the back contact cell is simplified.

Description

TECHNICAL FIELD

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

[0002] The back contact cell (BC cell) is a general term for various types of back contact structure crystalline silicon solar cells, including the interdigitated back contact cell (IBC cell), the tunnel oxide passivated back contact cell (TBC cell), the heterojunction back contact cell (HBC cell), the hybrid passivated back contact cell (HPBC cell), etc. The electrodes of the back contact cell are located on the back surface of the cell. This electrode distribution manner makes the front surface of the back contact electrode free from electrode shading, thereby effectively increasing the light receiving area of the cell and improving the efficiency of the cell.

[0003] Please refer to Figure 1 , Figure 1 is a schematic diagram of the structure of the back surface of a typical existing back contact cell. As shown in the figure, the first type doped region 11 and the second type doped region 12 (one of the first type doped region and the second type doped region is a P-type doped region, and the other is an N-type doped region) of the back contact cell are both formed on the back surface of the substrate 10, the first electrode 13 of the back contact cell is formed on the first doped region 11, and the second electrode 14 is formed on the second type doped region 12. Among them, the first electrode 13 and the second electrode 14 are both designed as a comb structure and the comb teeth of the two are arranged in a cross manner. This comb structure design has the advantages of improving the efficiency of the cell, reducing the series resistance, reducing the optical loss and contact recombination loss, etc. Since the first electrode and the second electrode of the existing back contact cell are formed on the first type doped region and the second type doped region respectively, the first type doped region 11 and the second type doped region 12 are also designed as a comb structure and the comb teeth of the two are arranged in a cross manner.

[0004] In the current technology, the first type doped region and the second type doped region on the back surface of the back contact cell are mainly formed by laser method or ink method.

[0005] The process of forming the back surface doping region of the back contact cell by the laser method is as follows: first, a mask layer is formed on the back surface of the substrate, and the mask layer is etched by laser to expose the region of the back surface of the substrate to be formed into the first type of doping region, then the exposed region is doped to form the first type of doping region, and the mask layer is removed. Then the above steps are repeated to form the second type of doping region in the corresponding region of the back surface of the substrate. Since the first type of doping region and the second type of doping region of the existing back contact cell are in a comb structure, the corresponding shape needs to be etched on the mask layer by laser. The comb structure is relatively complex, that is, there are multiple intersection regions and corner regions between the comb stems and the comb teeth. In this case, when forming the above corner regions and intersection regions, on the one hand, the laser spot often overlaps, thereby causing high damage to the local cell and affecting the performance of the cell, and on the other hand, the long laser etching time leads to the reduction of the production efficiency of the cell.

[0006] The process of forming the back surface doping region of the back contact cell by the ink method is as follows: first, an ink layer is formed on the back surface of the substrate by screen printing, the ink layer exposes the region of the back surface of the substrate to be formed into the first type of doping region, then the exposed region is doped to form the first type of doping region, and the ink layer is removed. Then the above steps are repeated to form the second type of doping region in the corresponding region of the back surface of the substrate. Since the viscosity of the ink is high, high plate spacing and high pressure are required in the process of printing the ink. In this case, the screen printing pattern is prone to deformation, thereby causing the deformation of the ink layer pattern. For the first type of doping region and the second type of doping region in the existing comb structure, the deformation of the ink layer pattern at the intersection region and the corner region between the comb stems and the comb teeth will be more serious, thereby causing the deformation of the doping region, and the deformed doping region is difficult to be completely aligned with the metallization region in the subsequent process, thereby affecting the performance of the cell.

[0007] That is, for the existing back contact cell, the first electrode and the second electrode are formed on the first type of doping region and the second type of doping region in this design, which limits the first type of doping region and the second type of doping region in a comb structure. The limitation of such doping region has certain adverse effects on the performance and production efficiency of the back contact cell. SUMMARY

[0008] In order to overcome the above-mentioned defects in the prior art, the present application provides a back contact cell, which comprises:

[0009] a substrate;

[0010] a doping region formed on the back surface of the substrate, the doping region comprising two or more first type of doping units and two or more second type of doping units, wherein the first type is one of P type and N type, and the second type is the other of P type and N type;

[0011] an insulating layer formed on the back surface of the substrate and covering the doped regions, the insulating layer being provided with first contact holes in a first region corresponding to each of the first-type doped units, and second contact holes in a second region corresponding to each of the second-type doped units;

[0012] a first electrode and a second electrode formed on a side of the insulating layer facing away from the substrate, the first electrode forming ohmic contact with the first-type doped units through the first contact holes, and the second electrode forming ohmic contact with the second-type doped units through the second contact holes, wherein the first electrode spans at least part of the second-type doped units and is isolated from the corresponding second-type doped units by the insulating layer, and / or the second electrode spans at least part of the first-type doped units and is isolated from the corresponding first-type doped units by the insulating layer.

[0013] According to an aspect of the present application, in the back contact cell, the first-type doped units and the second-type doped units are both in the shape of long strips, and the first-type doped units and the second-type doped units are alternately arranged along a first direction on the back surface of the substrate; the first contact holes provided in all the first regions form a first hole array, the first hole array includes two or more columns, and the first contact holes in each column are arranged in a straight line along the first direction, wherein the columns in the first hole array are divided into at least two first column units, and each first column unit includes at least one column; the second contact holes provided in all the second regions form a second hole array, the second hole array includes two or more columns, and the second contact holes in each column are arranged in a straight line along the first direction, wherein the columns in the second hole array are divided into at least two second column units, and each second column unit includes at least one column; the first column units in the first hole array and the second column units in the second hole array are alternately arranged.

[0014] According to another aspect of the present application, in the back contact cell, the number and size of the first contact holes provided in all the first regions are equal, wherein the first contact holes provided in each first region are arranged in a row at equal intervals along the length direction of the first region and are centrally arranged in the width direction of the first region; the number and size of the second contact holes provided in all the second regions are equal, wherein the second contact holes provided in each second region are arranged in a row at equal intervals along the length direction of the second region and are centrally arranged in the width direction of the second region.

[0015] According to still another aspect of the present application, in the back contact cell, for any one of the first region and the second region, if the shape of the contact hole on the region is circular, D represents the width of the region, d represents the diameter of the contact hole, L represents the distance between the centers of two adjacent contact holes on the same region, A represents the distance between the contact hole and the edge of the region, and B represents the distance between two adjacent contact holes on the same region, then A=(D-d) / 2, B=L-d, and 0≤|A-B|≤3d; for any one of the first region and the second region, if the shape of the contact hole on the region is rectangular, D represents the width of the region, a represents the size of the contact hole in the length direction of the region, b represents the size of the contact hole in the width direction of the region, L represents the distance between the centers of two adjacent contact holes on the same region, A represents the distance between the contact hole and the edge of the region, and B represents the distance between two adjacent contact holes on the same region, then A=(D-b) / 2, B=L-a, and A / 2≤B≤A.

[0016] According to still another aspect of the present application, in the back contact cell, each of the first column units comprises one column, and each of the second column units comprises one column; the first electrode comprises first gate lines corresponding to the columns in the first hole array one by one, each of the first gate lines forms ohmic contact with the first type doped units through the first contact holes in the column corresponding thereto; and the second electrode comprises second gate lines corresponding to the second column units in the second hole array one by one, each of the second gate lines comprises a second gate line corresponding to one column in the second column unit and a first bus gate line, wherein the second gate line forms ohmic contact with the second type doped units through the second contact holes in the column corresponding thereto, and the second contact holes in other columns in the second column unit are connected to the second gate line through the first bus gate line.

[0017] According to still another aspect of the present application, in the back contact cell, each of the first column units comprises one column, and each of the second column units comprises at least two columns; the first electrode comprises first gate lines corresponding to the columns in the first hole array one by one, each of the first gate lines forms ohmic contact with the first type doped units through the first contact holes in the column corresponding thereto; and the second electrode comprises gate line units corresponding to the second column units in the second hole array one by one, each of the gate line units comprises a second gate line corresponding to one column in the second column unit and a first bus gate line, wherein the second gate line forms ohmic contact with the second type doped units through the second contact holes in the column corresponding thereto, and the second contact holes in other columns in the second column unit are connected to the second gate line through the first bus gate line.

[0018] According to yet another aspect of the present application, in the back contact cell, each of the first grid lines and the second grid lines is a straight grid line; or each of the first grid lines comprises at least two first grid line segments arranged along the first direction and spaced apart by first gaps, the number of the first gaps in each of the first grid lines is the same, and the corresponding first gaps in all of the first grid lines are arranged in a straight line in a direction perpendicular to the first direction, wherein the corresponding first grid line segments in all of the first grid lines form a first grid line group; each of the second grid lines comprises at least two second grid line segments arranged along the first direction and spaced apart by second gaps, the number of the second gaps in each of the second grid lines is the same, and the corresponding second gaps in all of the second grid lines are arranged in a straight line in a direction perpendicular to the first direction, wherein the second gaps and the first gaps are arranged alternately, and the corresponding second grid line segments in all of the second grid lines form a second grid line group.

[0019] According to yet another aspect of the present application, in the back contact cell, for the case that each of the first grid lines and the second grid lines is a straight grid line, the first electrode further comprises a second bus grid line, the second bus grid line is arranged on one side of the doped region in the first direction and connected with the end portions of all of the first grid lines; and the second electrode further comprises a third bus grid line, the third bus grid line is arranged on the other side of the doped region in the first direction and connected with the end portions of all of the second grid lines.

[0020] According to yet another aspect of the present application, in the back contact cell, for the case that each of the first grid lines comprises first grid line segments and each of the second grid lines comprises second grid line segments, the first electrode further comprises fourth bus grid lines corresponding to the first grid line groups one by one, each of the fourth bus grid lines is connected with the first grid line segments in the corresponding first grid line group, wherein for any of the fourth bus grid lines, it is arranged on one side of the doped region in the first direction or arranged in one of the second gaps; and the second electrode further comprises fifth bus grid lines corresponding to the second grid line groups one by one, each of the fifth bus grid lines is connected with the second grid line segments in the corresponding second grid line group, wherein for any of the fifth bus grid lines, it is arranged on one side of the doped region in the first direction or arranged in one of the first gaps.

[0021] According to another aspect of the present application, in the back contact cell, the first type doped unit and the second type doped unit are both in the shape of a regular polygon; each of the first regions is provided with a first contact hole at the center of the first region, and each of the second regions is provided with a second contact hole at the center of the second region; at least one side of any of the first type doped units is connected to the second type doped unit, and at least one side of any of the second type doped units is connected to the first type doped unit.

[0022] The back contact cell provided by the present application comprises a substrate, a doped region, an insulating layer and a back electrode. The doped region is formed on the back of the substrate and comprises a first type doped region and a second type doped region; the first type doped region further comprises two or more first type doped units, and the second type doped region further comprises two or more second type doped units; the insulating layer is formed on the back of the substrate and covers the doped region; the insulating layer is provided with a first contact hole in a first region corresponding to the first type doped unit, and a second contact hole in a second region corresponding to the second type doped unit; the back electrode comprises a first electrode and a second electrode; the first electrode forms an ohmic contact with the first type doped unit through the first contact hole, and the second electrode forms an ohmic contact with the second type doped unit through the second contact hole; wherein the first electrode crosses the second type doped unit, and / or the second electrode crosses the first type doped unit. Since the first electrode crosses at least part of the second type doped unit and is isolated from the corresponding second type doped unit by the insulating layer, and / or the second electrode crosses at least part of the first type doped unit and is isolated from the corresponding first type doped unit by the insulating layer, i.e. the first electrode is no longer limited to being formed on the first type doped region and the second electrode is no longer limited to being formed on the second type doped region as in the prior art, the shape of the first type doped region and the second type doped region is no longer limited to the complex comb-shaped structure of the prior art, but can be achieved by using a simple shape. Through reasonable design of the shape of the first type doped region and the second type doped region, when the first type doped region and the second type doped region are formed by laser method, on the one hand, the damage to the local cell caused by high overlap of laser spots can be effectively avoided, and on the other hand, the formation efficiency of the doped region can be improved, thereby improving the production efficiency of the cell. When the first type doped region and the second type doped region are formed by ink method, it is beneficial to reduce the pattern deformation degree of the ink layer, so that the doped region and the metallized region are aligned as much as possible, thereby being beneficial to ensuring the performance of the cell. BRIEF DESCRIPTION OF DRAWINGS

[0023] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments made with reference to the following drawings:

[0024] Figure 1 is a top view of the back surface of a back contact cell in the prior art;

[0025] Fig. 2(a) is a top view of the back surface of a back contact cell according to one embodiment of the present application;

[0026] Fig. 2(b) is a top view of the back surface of a back contact cell according to another embodiment of the present application;

[0027] Fig. 2(c) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0028] Fig. 2(d) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0029] Fig. 2(e) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0030] Fig. 2(f) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0031] Fig. 2(g) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0032] Fig. 2(h) is a top view of the back surface of a back contact cell according to yet another embodiment of the present application;

[0033] Fig. 3(a) is a layout of the first type of doped units and the second type of doped units on the back surface of the substrate in the back contact cells shown in Figs. 2(a), 2(c), 2(e), and 2(g), wherein the first type of doped units and the second type of doped units are both long rectangular shapes and have the same width;

[0034] Fig. 3(b) is a top view of the insulating layer in the back contact cells shown in Figs. 2(a), 2(c), 2(e), and 2(g);

[0035] Fig. 4(a) is a layout of the first type of doped units and the second type of doped units on the back surface of the substrate in the back contact cells shown in Figs. 2(b), 2(d), 2(f), and 2(h), wherein the first type of doped units and the second type of doped units are both long rectangular shapes but have different widths;

[0036] Fig. 4(b) is a top view of the insulating layer in the back contact cells shown in Figs. 2(b), 2(d), 2(f), and 2(h);

[0037] Fig. 5(a) is a schematic diagram of the back surface structure of a back contact cell according to yet another embodiment of the present application;

[0038] Fig. 5(b) is a layout diagram of the first type doped units and the second type doped units on the back surface of the substrate in the back contact cell shown in Fig. 5(a), wherein the first type doped units and the second type doped units are both hexagonal in shape and arranged in a honeycomb pattern.

[0039] The same or similar reference signs in the drawings represent the same or similar components.

[0040] Reference signs

[0041] 100a - first type doped region, 100b - second type doped region, 100c - isolation region, 101a - first region, 101b - second region, 101c - third region, 102a - first contact hole, 102b - second contact hole, 103a - first column structure, 103b - second column structure, 104a - first gate line, 104a' - first gate line segment, 104b - second gate line, 104b' - second gate line segment, 105a - first bus gate line, 105b - second bus gate line, 105c - third bus gate line, 105d - fourth bus gate line, 105e - fifth bus gate line. DETAILED DESCRIPTION

[0042] In order to better understand and illustrate the present application, the present application will be further described in detail below with reference to the accompanying drawings.

[0043] The present application provides a back contact cell, which comprises:

[0044] a substrate;

[0045] a doped region formed on the back surface of the substrate, the doped region comprising two or more first type doped units and two or more second type doped units, wherein the first type is one of P type and N type, and the second type is the other of P type and N type;

[0046] an insulating layer formed on the back surface of the substrate and covering the doped region, the insulating layer being provided with a first contact hole on a first region corresponding to each of the first type doped units, and being provided with a second contact hole on a second region corresponding to each of the second type doped units;

[0047] a first electrode and a second electrode formed on a side of the insulating layer facing away from the substrate, the first electrode forming an ohmic contact with the first type doped units through the first contact holes, and the second electrode forming an ohmic contact with the second type doped units through the second contact holes, wherein the first electrode spans at least part of the second type doped units and is isolated from the corresponding second type doped units by the insulating layer, and / or the second electrode spans at least part of the first type doped units and is isolated from the corresponding first type doped units by the insulating layer.

[0048] The various components of the back contact cell will be described in detail below.

[0049] Specifically, the back contact cell provided by the present application comprises a substrate, which comprises a front surface and a back surface opposite to the front surface, wherein the front surface of the substrate is used to constitute a light-receiving surface of the back contact cell, and the back surface of the substrate is used to constitute a back surface of the back contact cell. The present application does not make any limitation on the material of the substrate, and any material suitable for the substrate of a solar cell at present and in the future falls within the scope of protection of the present application, such as silicon and the like. For the sake of simplicity, all possible materials of the substrate will not be listed one by one herein. In addition, the present application also does not make any limitation on the size of the substrate, which can be determined according to the actual design requirements.

[0050] The back contact cell provided by the present application further comprises a doped region formed on the back surface of the substrate. In the present embodiment, the doped region comprises a first type doped region and a second type doped region, the first type doped region further comprises two or more first type doped units, and the second type doped region further comprises two or more second type doped units. Wherein the first type is one of P type and N type, and the second type is the other of P type and N type, i.e. the first type is P type and the second type is N type, or the first type is N type and the second type is P type.

[0051] The back contact cell further comprises an insulating layer formed on the back surface of the substrate and covering the entire doped region. In the embodiment, the insulating layer is made of insulating materials such as silicon nitride, silicon oxide, aluminum oxide, magnesium fluoride, titanium oxide, or a combination thereof, and preferably has a thickness ranging from 60 nm to 100 nm. Those skilled in the art can understand that the material of the insulating layer is not limited to the above-mentioned materials, and the thickness is not limited to the above-mentioned preferred range, and can be selected and determined according to the actual design requirements. For the sake of brevity, all possible options are not listed here. For any first-type doped unit, the area of the insulating layer corresponding to the first-type doped unit (i.e., the area covering the surface of the first-type doped unit) is hereinafter referred to as a first area. Similarly, for any second-type doped unit, the area of the insulating layer corresponding to the second-type doped unit (i.e., the area covering the surface of the second-type doped unit) is hereinafter referred to as a second area. In the embodiment, each first area of the insulating layer is provided with at least one through hole in the thickness direction, which is hereinafter referred to as a first contact hole. Similarly, each second area of the insulating layer is also provided with at least one through hole in the thickness direction, which is hereinafter referred to as a second contact hole. The present application does not make any limitation on the shape of the first contact hole and the second contact hole, and preferably is an axisymmetric figure such as a circle, a rectangle, etc. Those skilled in the art can understand that the above-mentioned axisymmetric figure is only a preferred embodiment, which should not be regarded as a limitation on the shape of the first contact hole and the second contact hole. For the sake of brevity, all possible shapes of the first contact hole and the second contact hole are not listed here. The shape of the first contact hole and the second contact hole can be the same or different, and the present application does not make any limitation thereon. In addition, the present application does not make any limitation on the specific size of the first contact hole and the second contact hole.

[0052] The back contact battery provided by the present application further comprises a back electrode formed on the side of the insulating layer away from the substrate. In the present embodiment, the back electrode further comprises a first electrode and a second electrode, the first electrode forms ohmic contact with the first type doped units through the first contact holes, and the second electrode forms ohmic contact with the second type doped units through the second contact holes, wherein the first electrode spans at least part of the second type doped units, and the second electrode spans at least part of the first type doped units. Here, the first electrode spanning at least part of the second type doped units means that the first electrode passes over at least one second type doped unit (i.e. the horizontal projection of the first electrode on the back of the substrate will have part falling within the area where at least one second type doped unit is located), and similarly, the second electrode spanning at least part of the first type doped units means that the second electrode passes over at least one first type doped unit (i.e. the horizontal projection of the second electrode on the back of the substrate will have part falling within the area where at least one first type doped unit is located). Due to the presence of the insulating layer, the first electrode is isolated from the second type doped units it spans, and the second electrode is isolated from the first type doped units it spans. Those skilled in the art can understand that in other embodiments, the first electrode can span at least part of the second type doped units, and the second electrode can not span the first type doped units (i.e. the horizontal projection of the second electrode on the back of the substrate will only fall within the area where the second type doped units are located); or the second electrode can span at least part of the first type doped units, and the first electrode can not span the second type doped units (i.e. the horizontal projection of the first electrode on the back of the substrate will only fall within the area where the first type doped units are located). The present application does not make any limitation on the materials of the first electrode and the second electrode, and conventional materials of existing electrodes such as silver and aluminum can be used. For the sake of simplicity, all possible materials of the first electrode and the second electrode are not listed here.

[0053] It should be noted that the improvement of the back contact battery of the present application is mainly on the back of the battery, therefore the front structure of the back contact battery provided by the present application can adopt the existing design, for example, the front of the substrate has a textured structure, and the front of the substrate sequentially forms a passivation layer and an anti-reflection layer, etc. The present application does not make any limitation on this, and for the sake of simplicity, all possible front structures of the back contact battery are not listed here.

[0054] The back contact cell of the prior art adopts the design of the comb-shaped structure on the back surface, and is limited by the first electrode formed on the first type of doped region and the second electrode formed on the second type of doped region, so that the first type of doped region and the second type of doped region also present a comb-shaped structure. Due to the relatively complex comb-shaped structure, there are multiple intersections and corner regions between the comb stems and the comb teeth, so that when the first type of doped region and the second type of doped region are formed by using the prior art process, the problems of high laser spot overlap, long laser etching time, and serious pattern deformation occur. The back contact cell provided by the present application forms an insulating layer on the first type of doped region and the second type of doped region, and the insulating layer is provided with a first contact hole exposing the first type of doped region and a second contact hole exposing the second type of doped region. The first electrode forms ohmic contact with the first type of doped region through the first contact hole, and the second electrode forms ohmic contact with the second type of doped region through the second contact hole. Due to the provision of the insulating layer with the contact holes, the first electrode and the second electrode are no longer limited to being formed only on the corresponding doped region. In this way, the first electrode can form ohmic contact with the first type of doped region across the second type of doped region, and the second electrode can form ohmic contact with the second type of doped region across the first type of doped region. This flexible electrode layout across the doped region does not have strict requirements on the shape of the first type of doped region and the second type of doped region, i.e., the first type of doped region and the second type of doped region do not need to adopt the complex comb-shaped structure of the prior art, but can be implemented by using a simple shape (for example, a shape not including corner regions and intersection regions, or a shape including as few corner regions and intersection regions as possible). In this case, when the first type of doped region and the second type of doped region are formed by using the laser method, due to the simple shape of the first type of doped region and the second type of doped region, the phenomenon of high laser spot overlap can be reduced or even avoided to reduce the damage to the cell, and the formation speed of the doped region can be accelerated to improve the production efficiency of the cell. Similarly, when the first type of doped region and the second type of doped region are formed by using the ink method, due to the simple shape of the first type of doped region and the second type of doped region, the deformation degree of the ink layer pattern can be effectively reduced, so that the doped region and the metallization region are aligned as much as possible to facilitate ensuring the performance of the cell.

[0055] In one specific embodiment, the first type doped units and the second type doped units on the back surface of the substrate in the back contact cell are all in the shape of long strips, and the first type doped units and the second type doped units are arranged alternately along the first direction on the back surface of the substrate. Preferably, all the first type doped units and the second type doped units are in the shape of long rectangular strips, and all the first type doped units have the same width, and all the second type doped units have the same width. Those skilled in the art can understand that the width of all the first type doped units can also be different, and the width of all the second type doped units can also be different according to actual design requirements. In addition, the width of the first type doped units and the width of the second type doped units can be the same or different, which is not limited herein. Compared with the complex comb-shaped structure in the prior art, the long rectangular shape of the first type doped units and the second type doped units in the present embodiment is obviously simpler. It should be noted that, in order to prevent short circuit phenomenon, an isolation region is usually arranged between adjacent first type doped units and second type doped units. The present application does not make specific limitations on the structure of the isolation region, and any isolation structure having an electrical isolation function and suitable for a solar cell is suitable for the isolation region in the present application. Considering that the arrangement of the isolation region is a conventional technical means in the art, in order to be simple, all possible structures of the isolation region are not listed herein. The first contact holes opened on all the first regions on the insulating layer form an array (hereinafter referred to as a first hole array), wherein the first hole array includes two or more columns, and the first contact holes in each column are arranged in a straight line along the first direction. In the present embodiment, all the columns in the first hole array are divided into at least two units (hereinafter referred to as first column units), wherein each first column unit includes at least one column. It should be noted that all the columns in the first hole array are divided according to their arrangement order, that is, when the first column unit includes two or more columns, the two or more columns are adjacent in the first hole array. Similarly, the second contact holes opened on all the second regions on the insulating layer also form an array (hereinafter referred to as a second hole array), wherein the second hole array includes two or more columns, and the second contact holes in each column are arranged in a straight line along the first direction. In the present embodiment, all the columns in the second hole array are divided into at least two units (hereinafter referred to as second column units), wherein each second column unit includes at least one column. It should be noted that all the columns in the second hole array are divided according to their arrangement order, that is, when the second column unit includes two or more columns, the two or more columns are adjacent in the second hole array. The first column units in the first hole array and the second column units in the second hole array are arranged alternately. It should be noted that the present application does not limit the number of columns in each first column unit in the first hole array, which can be the same or different; similarly, the present application does not limit the number of columns in each second column unit in the second hole array, which can be the same or different.For example, each first column unit in the first hole array includes one column, and each second column unit in the second hole array also includes one column, i.e. the columns in the first hole array and the columns in the second hole array are arranged alternately; for another example, each first column unit in the first hole array includes one column, and each second column unit in the second hole array includes two or more columns, i.e. there are two or more columns in the second hole array between two adjacent columns in the first hole array; for yet another example, each first column unit in the first hole array includes two or more columns, and each second column unit in the second hole array includes one column, i.e. there are two or more columns in the first hole array between two adjacent columns in the second hole array; and the like.

[0056] Further, the first contact holes with equal number and equal size are formed on all the first regions on the insulating layer, wherein the first contact holes on each first region are arranged equidistantly into a row along the length direction of the first region and are arranged centrally in the width direction of the first region. Similarly, the second contact holes with equal number and equal size are formed on all the second regions on the insulating layer, wherein the second contact holes on each second region are arranged equidistantly into a row along the length direction of the second region and are arranged centrally in the width direction of the second region. It can be understood by those skilled in the art that (1) the equal size of the contact holes herein means that the actual size difference of the contact holes is controlled within the error range allowed by the process or design; (2) the equal size of all the first contact holes is only a preferred embodiment, and in other embodiments, the sizes of the first contact holes can also be different. The same is true for the second contact holes; (3) the formation of one row of first contact holes on the first region is only a preferred embodiment, and in other embodiments, two or more rows of first contact holes can also be formed on the first region according to actual design requirements, which is not limited in the present application. The same is true for the second contact holes; (4) the central arrangement of the first contact holes in the width direction of the first region is only a preferred embodiment, and in other embodiments, the first contact holes can not be arranged centrally, which is not limited in the present application. The same is true for the second contact holes; (5) the present application does not make any limitation on the specific shape of the first contact holes and the second contact holes, and it is preferred to use axisymmetric figures such as circles and rectangles, and for the sake of simplicity, all possible shapes of the first contact holes and the second contact holes are not listed one by one herein.

[0057] The specific arrangement of the contact holes will be described below taking the first type of doped units and the second type of doped units as long rectangular shapes and the contact holes as circles and rectangles as examples.

[0058] In one embodiment, the contact holes (including the first contact holes and the second contact holes) are circular. In the case where the contact holes are arranged in a row along the length direction of the region where the contact holes are located (the region where the first contact holes are located is the first region, and the region where the second contact holes are located is the second region) and are centrally arranged in the width direction of the region, D represents the width of the region where the contact holes are located, d represents the diameter of the contact hole, L represents the distance between the centers of two adjacent contact holes in the same region, A represents the distance between the contact hole and the edge of the region, and B represents the distance between two adjacent contact holes in the same region, wherein A=(D-d) / 2 and B=L-d. In this embodiment, when the width of the region where the contact holes are located is determined, the diameter of the contact hole and the distance between the centers of two adjacent contact holes are reasonably set so that A and B satisfy 0≤|A-B|≤3d. When the circular contact holes are arranged according to the above conditions, the current collection efficiency of the electrode is improved.

[0059] In another embodiment, the contact holes are rectangular. In the case where the contact holes are arranged in a row along the length direction of the region where the contact holes are located and are centrally arranged in the width direction of the region, D represents the width of the region where the contact holes are located, a and b represent the length and the width of the contact hole (here, the length refers to the size of the contact hole in the length direction of the region where the contact hole is located, and the width refers to the size of the contact hole in the width direction of the region where the contact hole is located), L represents the distance between the centers of two adjacent contact holes in the same region, A represents the distance between the contact hole and the edge of the region, and B represents the distance between two adjacent contact holes in the same region, wherein A=(D-b) / 2 and B=L-a. In this embodiment, when the width of the region where the contact holes are located is determined, the diameter of the contact hole and the distance between the centers of two adjacent contact holes are reasonably set so that A / 2≤B≤A. When the rectangular contact holes are arranged according to the above conditions, the current collection efficiency of the electrode is improved.

[0060] The back contact cell provided by the present application is described below by taking the first type of doped units and the second type of doped units as long rectangular shapes and the first contact holes and the second contact holes as circular shapes as examples. It should be noted that, since the improvement of the present application on the back contact cell is mainly on the back surface of the cell, the structure of the back surface of the back contact cell is described here, and the structure of the front surface of the back contact cell is omitted.

[0061] Referring to FIG. 2(a), FIG. 3(a) and FIG. 3(b), FIG. 2(a) is a schematic top view of the back surface of a back contact cell according to an embodiment of the present application, FIG. 3(a) is a schematic layout of the first type doped units and the second type doped units on the back surface of the back contact cell shown in FIG. 2(a), and FIG. 3(b) is a schematic top view of the insulating layer of the back contact cell shown in FIG. 2(a). As shown in FIG. 3(a), the first type doped units 100a and the second type doped units 100b are both long rectangular in shape and are arranged alternately along the first direction. In this embodiment, the first type doped units 100a and the second type doped units 100b have the same width. An isolation region 100c is provided between the first type doped units 100a and the second type doped units 100b, between the first type doped units 100a and the edge of the substrate, and between the second type doped units 100b and the edge of the substrate. As shown in FIG. 3(b), a first region in the insulating layer corresponding to the first type doped units 100a is denoted by 101a, a second region in the insulating layer corresponding to the second type doped units 100b is denoted by 101b, and a third region in the insulating layer corresponding to the isolation region 100c is denoted by 100c. A first contact hole 102a is formed on the first region, and a second contact hole 102b is formed on the second region 101b. The first contact hole 102a and the second contact hole 102b are both circular in shape, wherein the diameter of the first contact hole 102a is equal to the diameter of the second contact hole 102b, and the distance between two adjacent first contact holes 102a is the same as the distance between two adjacent second contact holes 102b. All the first contact holes 102a form a first hole array, which comprises a plurality of columns, and the first contact holes 102a in each column are arranged in a straight line along the first direction. All the second contact holes 102b form a second hole array, which comprises a plurality of columns, and the second contact holes 102b in each column are arranged in a straight line along the first direction. The columns in the first hole array are divided into a plurality of first column units 103a, and the columns in the second hole array are divided into a plurality of second column units 103b. In this embodiment, each first column unit 103a comprises only one column, and each second column unit 103b also comprises only one column. The first column units 103a and the second column units 103b are arranged alternately (i.e., the columns in the first hole array and the columns in the second hole array are arranged alternately). As shown in FIG. 2(a), the first electrode comprises a first gate line unit, the number of the first gate line units is the same as the number of the first column units 103a in the first hole array, and each first gate line unit corresponds to a first column unit 103a. In this embodiment, each first gate line unit comprises a first gate line 104a in a straight line shape. The first gate line 104a forms an ohmic contact with the first type doped units 100a through the first contact holes 102a in the first column unit 103a corresponding to the first gate line 104a, while the first gate line 104a spans the second type doped units 100b.The second electrode comprises second gate line units, the number of the second gate line units is the same as the number of the second column units 103b in the second hole array, and each second gate line unit corresponds to a second column unit 103b. In this embodiment, each second gate line unit comprises a second gate line 104b in a straight line shape, the second gate line 104b forms an ohmic contact with the second type doped unit 100b through the second contact hole 102b in the second column unit 103b corresponding to the second gate line 104b, and at the same time the second gate line 104b crosses the first type doped unit 100a. In order to realize good ohmic contact between the gate line and the doped unit, preferably, the width of the first gate line 104a is greater than the diameter of the first contact hole 102a, and the first gate line 104a completely covers the first contact hole 102a, and the width of the second gate line 104b is greater than the diameter of the second contact hole 102b, and the second gate line 104b completely covers the second contact hole 102b.

[0062] Referring to FIG. 2(b), which is a top view of the back surface of a back contact cell according to another specific embodiment of the present application, FIG. 4(a) is a layout diagram of the first type doped units and the second type doped units on the back surface of the substrate in the back contact cell shown in FIG. 2(b), and FIG. 4(b) is a top view of the insulating layer in the back contact cell shown in FIG. 2(b). As shown in FIG. 4(a), the first type doped units 100a and the second type doped units 100b are both long rectangular in shape and are arranged alternately along the first direction. In this embodiment, the first type doped units 100a and the second type doped units 100b have different widths, specifically, the width of the first type doped units 100a is smaller than the width of the second type doped units 100b. An isolation region 100c is provided between the first type doped units 100a and the second type doped units 100b, between the first type doped units 100a and the edge of the substrate, and between the second type doped units 100b and the edge of the substrate. As shown in FIG. 4(b), a first region in the insulating layer corresponding to the first type doped units 100a is denoted by 101a, a second region in the insulating layer corresponding to the second type doped units 100b is denoted by 101b, and a third region in the insulating layer corresponding to the isolation region 100c is denoted by 100c. A first contact hole 102a is opened on the first region, and a second contact hole 102b is opened on the second region 101b. The first contact hole 102a and the second contact hole 102b are both circular in shape, and the diameter of the first contact hole 102a is equal to that of the second contact hole 102b. However, the distance between adjacent two first contact holes 102a is different from the distance between adjacent two second contact holes 102b, specifically, the distance between adjacent two first contact holes 102a is smaller than the distance between adjacent two second contact holes 102b. All the first contact holes 102a form a first hole array, which includes a plurality of columns, and the first contact holes 102a in each column are arranged in a straight line along the first direction. All the second contact holes 102b form a second hole array, which also includes a plurality of columns, and the second contact holes 102b in each column are arranged in a straight line along the first direction. The columns in the first hole array are divided into a plurality of first column units 103a, and the columns in the second hole array are divided into a plurality of second column units 103b. In this embodiment, each first column unit 103a includes only one column, and each second column unit 103b includes three columns, and the first column units 103a and the second column units 103b are arranged alternately (i.e., one column in the first hole array and three columns in the second hole array are arranged alternately). As shown in FIG. 2(b), the first electrode includes a first gate line unit, the number of the first gate line unit is the same as the number of the first column units 103a in the first hole array, and each first gate line unit corresponds to a first column unit 103a.In the embodiment, each first gate line unit includes a first gate line 104a in a straight line shape, which forms an ohmic contact with the first type doped unit 100a through the first contact hole 102a in the first column unit 103a corresponding to the first gate line 104a, while the first gate line 104a spans the second type doped unit 100b. The second electrode includes second gate line units, the number of which is the same as the number of the second column units 103b in the second hole array, and each of which corresponds to one of the second column units 103b. In the embodiment, each second gate line unit includes a second gate line 104b and a first bus gate line 105a, wherein the number of the second gate line 104b is one, corresponding to one of the second column units 103b, and the number of the second bus gate line 105a is the same as the number of the rows in the second hole array, and corresponds to each of the rows. The second gate line 104b forms an ohmic contact with the second type doped unit 100b through the second contact hole 102b in the column corresponding to the second gate line 104b in the second column unit 103b, while the second gate line 104b spans the first type doped unit 100a, and the other second contact holes 102b in the second column unit 103b are connected to the second gate line 104b through the first bus gate line 105a corresponding to the row in which the second contact holes 102b are located. In order to achieve good ohmic contact between the gate line and the doped unit, preferably, the width of the first gate line 104a is greater than the diameter of the first contact hole 102a, and the first gate line 104a completely covers the first contact hole 102a, and the width of the second gate line 104b and the first bus gate line 105a is greater than the diameter of the second contact hole 102b, and the second gate line 104b and the first bus gate line 105a completely cover the second contact hole 102b.

[0063] Referring to FIG. 2(c), FIG. 2(c) is a top view of the back surface of a back contact cell according to still another embodiment of the present application, wherein the structure shown in FIG. 2(c) is different from that shown in FIG. 2(a) in the specific structure of the first grid lines and the second grid lines. In the present embodiment, each first grid line comprises at least two first grid line segments 104a' arranged in the first direction with a certain interval (hereinafter referred to as first gap) between adjacent first grid line segments 104a'. All the first grid lines in the present embodiment comprise the same number of first grid line segments 104a', and the first grid line segments 104a' corresponding in position in each first grid line have the same length, i.e., the corresponding first gaps in all the first grid lines are arranged in a straight line in the direction perpendicular to the first direction. Hereinafter, all the first grid line segments 104a' corresponding in position in all the first grid lines are defined as a first grid line group. In the present embodiment, as shown in FIG. 2(c), each first grid line comprises four first grid line segments 104a' arranged in the first direction, and accordingly, all the first grid lines constitute four first grid line groups. Similarly, each second grid line comprises at least two second grid line segments 104b' arranged in the first direction with a certain interval (hereinafter referred to as second gap) between adjacent second grid line segments 104b'. All the second grid lines in the present embodiment comprise the same number of second grid line segments 104b', and the second grid line segments 104b' corresponding in position in each second grid line have the same length, i.e., the corresponding second gaps in all the second grid lines are arranged in a straight line in the direction perpendicular to the first direction. Hereinafter, all the second grid line segments 104b' corresponding in position in all the second grid lines are defined as a second grid line group. In the present embodiment, as shown in FIG. 2(c), each second grid line comprises three second grid line segments 104b' arranged in the first direction, and accordingly, all the second grid lines constitute three second grid line groups.

[0064] Please refer to FIG. 2(d), which is a top view of the back of a back contact cell according to another embodiment of the present application. The structure shown in FIG. 2(d) is different from that shown in FIG. 2(b) in the specific structure of the first and second grid lines. In this embodiment, each first grid line comprises at least two first grid line segments 104a' arranged in the first direction with a first gap between adjacent first grid line segments 104a'. In this embodiment, all the first grid lines comprise the same number of first grid line segments 104a', and the first grid line segments 104a' corresponding in position in each first grid line have the same length, i.e. the corresponding first gaps in all the first grid lines are arranged in a straight line in the direction perpendicular to the first direction. Hereinafter, the first grid line segments 104a' corresponding in position in all the first grid lines are defined as a first grid line group. In this embodiment, as shown in FIG. 2(c), each first grid line comprises 3 first grid line segments 104a' arranged in the first direction, and accordingly all the first grid lines form 3 first grid line groups. Similarly, each second grid line comprises at least two second grid line segments 104b' arranged in the first direction with a second gap between adjacent second grid line segments 104b'. In this embodiment, all the second grid lines comprise the same number of second grid line segments 104b', and the second grid line segments 104b' corresponding in position in each second grid line have the same length, i.e. the corresponding second gaps in all the second grid lines are arranged in a straight line in the direction perpendicular to the first direction. Hereinafter, the second grid line segments 104b' corresponding in position in all the second grid lines are defined as a second grid line group. In this embodiment, as shown in FIG. 2(d), each second grid line comprises 2 second grid line segments 104b' arranged in the first direction, and accordingly all the second grid lines form 2 second grid line groups.

[0065] Please refer to FIG. 2(e), which is a top view of the back of a back contact cell according to another embodiment of the present application. The structure shown in FIG. 2(e) is different from that shown in FIG. 2(a) in the specific structure of the first and second electrodes. In this embodiment, the first electrode further comprises a second bus grid line 105b, and the second electrode further comprises a third bus grid line 105c, which are arranged on the two sides of the doped region in the first direction, wherein the second bus grid line 105b is connected with the end portions of all the first grid lines 104a for collecting the current on all the first grid lines 104a, and the third bus grid line 105c is connected with the end portions of all the second grid lines 104b for collecting the current on all the second grid lines 104b.

[0066] Please refer to FIG. 2(f), which is a top view of the back of a back contact cell according to another specific embodiment of the present application. The structure shown in FIG. 2(f) is different from that shown in FIG. 2(b) in the specific structure of the first and second electrodes. In this embodiment, the first electrode further includes a second busbar 105b and the second electrode further includes a third busbar 105c, which are respectively arranged on the two sides of the doped region in the first direction. The second busbar 105b is connected to the ends of all the first busbars 104a and is used to collect the current on all the first busbars 104a, and the third busbar 105c is connected to the ends of all the second busbars 104b and is used to collect the current on all the second busbars 104b.

[0067] Please refer to FIG. 2(g), which is a top view of the back of a back contact cell according to another specific embodiment of the present application. The structure shown in FIG. 2(g) is different from that shown in FIG. 2(c) in the specific structure of the first and second electrodes. In this embodiment, the first electrode further includes a fourth busbar 105d corresponding to each first busbar group, and each fourth busbar 105d is connected to the first busbar segment 104a' in the corresponding first busbar group to collect the current thereon. The second electrode further includes a fifth busbar 105e corresponding to each second busbar group, and each fifth busbar 105e is connected to the second busbar segment 104b' in the corresponding second busbar group to collect the current thereon. In this embodiment, for the first busbar group close to the edges of the doped region in the first direction, the corresponding fourth busbar 105d is arranged at the corresponding edge of the doped region; for other first busbar groups, the corresponding fourth busbar 105d is arranged in a second gap between the second busbar groups by proper arrangement; and for the second busbar group, the corresponding fifth busbar 105e is arranged in a first gap between the first busbar groups by proper arrangement. It should be noted that in other embodiments, if the second busbar group is arranged close to the edges of the doped region in the first direction, the corresponding fifth busbar can be arranged at the corresponding edge of the doped region.

[0068] Please refer to FIG. 2(h), which is a top view of the back surface of a back contact cell according to another specific embodiment of the present application. The structure shown in FIG. 2(h) is different from that shown in FIG. 2(d) in the specific structure of the first and second electrodes. In this embodiment, the first electrode further comprises fourth bus bars 105d corresponding to the first grid line groups one by one, each fourth bus bar 105d being connected to the first grid line segments 104a' in the corresponding first grid line group to converge the current thereon. The second electrode further comprises fifth bus bars 105e corresponding to the second grid line groups one by one, each fifth bus bar 105e being connected to the second grid line segments 104b' in the corresponding second grid line group to converge the current thereon. In this embodiment, for the first grid line groups close to the edges of the doped region in the first direction, the corresponding fourth bus bars 105d are arranged at the corresponding edges of the doped region; for other first grid line groups, the corresponding fourth bus bars 105d are arranged in a second gap between the second grid line groups by proper arrangement; for the second grid line groups, the corresponding fifth bus bars 105e are arranged in a first gap between the first grid line groups by proper arrangement. It should be noted that in other embodiments, if the second grid line groups are arranged close to the edges of the doped region in the first direction, the corresponding fifth bus bars can be arranged at the corresponding edges of the doped region. It should be noted that if the arrangement position of the fifth bus bar coincides with that of some first bus bars, the corresponding first bus bars can be omitted.

[0069] It should be noted that the first and second doped units are not limited to the above-mentioned long rectangular shape, but can also be other shapes, such as regular polygonal shape. For the case where the first and second doped units are regular polygonal shape, a first contact hole is formed in each first region and located at the center of the first region, a second contact hole is formed in each second region and located at the center of the second region, at least one side of any first doped unit is connected to a second doped unit, and at least one side of any second doped unit is connected to a first doped unit. Those skilled in the art can understand that, in order to prevent short circuit, an isolation region needs to be arranged between the first and second doped units, so "connected" here means connected through the isolation region, i.e., at least one side of any first doped unit is connected to a second doped unit through the isolation region, and at least one side of any second doped unit is connected to a first doped unit through the isolation region.

[0070] The following is described with reference to a specific embodiment. Please refer to FIG. 5(a) and FIG. 5(b), wherein FIG. 5(a) is a schematic top view of the back surface of a back contact cell according to another specific embodiment of the present application, and FIG. 5(b) is a schematic layout of the first type doped units and the second type doped units on the back surface of the back contact cell shown in FIG. 5(a). In this embodiment, as shown in FIG. 5(b), the first doped region includes a plurality of first type doped units 100a, and the second doped region includes a plurality of second type doped units 100b, wherein the first type doped units 100a and the second type doped units 100b are both regular hexagons, and the first type doped units 100a and the second type doped units 100b are arranged in a honeycomb pattern on the back surface of the substrate. Specifically, all the first type doped units 100a are arranged in an array, each column of the first type doped units 100a in the array is arranged in a straight line, and adjacent two columns of the first type doped units 100a are arranged staggeredly. The second type doped units 100b are formed between the first type doped units 100a and surround the first type doped units 100a. It should be noted that an isolation region is arranged between adjacent first type doped units 100a and second type doped units 100b, and the isolation region is omitted here for the sake of simplicity. The first region 101a on the insulating layer corresponding to the first type doped units 100a is provided with a first contact hole 102a, and in this embodiment, the number of the first contact hole 102a provided on each first region 101a is one, and the first contact hole 102a is located at the center of the first region 101a. The second region 101b on the insulating layer corresponding to the second type doped units 100b is provided with a second contact hole 102b, and in this embodiment, the number of the second contact hole 102b provided on each second region 101b is one, and the second contact hole 102b is located at the center of the second region 101b. The first electrode includes first gate lines 104a, the number of the first gate lines 104a is equal to the number of columns in the array formed by the first type doped units 100a and corresponds to the columns one by one, each first gate line 104a is in a straight line and forms an ohmic contact with the first type doped units 100a through the first contact hole 102a in the corresponding column, wherein since the second type doped units 100b are formed between the first type doped units 100a, the first gate line 104a forms an ohmic contact with the first type doped units 100a while crossing the second type doped units 100b. The second electrode includes second gate lines 104b, wherein for the second type doped units 100b between adjacent two columns in the array formed by the first type doped units 100a, the second gate line 104b is arranged to form an ohmic contact with the second type doped units 100b through the second contact hole 102b on the second type doped units 100b. In this embodiment, the second gate line 104b is implemented by a gate line in a zigzag shape, which is formed in the second region 101b without crossing the first type doped units 100a.

[0071] It should be noted that (1) the first contact hole 102a is arranged at the center of the first region 101a, which is beneficial to the convergence of the current on the first-type doped unit by the first electrode. Similarly, the second contact hole 102b is arranged at the center of the second region 101b, which is beneficial to the convergence of the current on the second-type doped unit by the second electrode. Those skilled in the art can understand that in other embodiments, the number and arrangement position of the first contact hole 102a and the second contact hole 102b can also be made according to the actual design requirements, and the present application does not make any limitation on this. (2) The layout mode of the first-type doped unit 100a and the second-type doped unit 100b in Figure 5(b) is only a preferred embodiment, and the first-type doped unit 100a and the second-type doped unit 100b can also adopt other layout modes according to their actual shapes, and the present application does not make any limitation on this. (3) In the present embodiment, the first electrode crosses the second-type doped unit 100b, and the second electrode is located in the second-type doped unit 100b. In other embodiments, the second electrode can also cross the first-type doped unit 100a, and the first electrode is located in the first-type doped unit 100a; or the first electrode crosses the second-type doped unit 100b, and the second electrode crosses the first-type doped unit 100a.

[0072] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Thus, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalents of the claims are therefore intended to be embraced therein. Any reference signs in the claims should not be construed as limiting the claims concerned. Furthermore, the word "comprising" does not exclude other parts, units or steps not mentioned or comprising other parts, units or steps. The singular does not exclude the plural and vice versa. Multiple components, units or devices recited in a system claim can be implemented by one component, unit or device performing the functions of said multiple components, units or devices by hardware or software.

[0073] The above disclosure is only some of the preferred embodiments of the present application, and of course cannot limit the scope of the rights of the present application, so the equivalent changes made according to the claims of the present application are still within the scope of the present application.

Claims

1. A back contact battery, the back contact battery comprising: Substrate; A doped region is formed on the back side of the substrate, the doped region comprising two or more first-type doped units and two or more second-type doped units, wherein the first type is one of P-type and N-type, and the second type is the other of P-type and N-type; An insulating layer is formed on the back side of the substrate and covers the doped region. A first contact hole is formed on the first region corresponding to each of the first type doped units, and a second contact hole is formed on the second region corresponding to each of the second type doped units. A first electrode and a second electrode are formed on the side of the insulating layer away from the substrate. The first electrode forms an ohmic contact with a first type doped cell through a first contact hole, and the second electrode forms an ohmic contact with a second type doped cell through a second contact hole. The first electrode spans at least a portion of the second type doped cell and is isolated from the corresponding second type doped cell through the insulating layer, and / or the second electrode spans at least a portion of the first type doped cell and is isolated from the corresponding first type doped cell through the insulating layer.

2. The back contact battery according to claim 1, wherein: Both the first type of doped unit and the second type of doped unit are elongated strips, and they are alternately arranged along the first direction on the back side of the substrate; All the first contact holes opened on the first region constitute a first hole array, the first hole array includes two or more columns, and the first contact holes in each column are arranged in a straight line in the first direction, wherein the columns in the first hole array are divided into at least two first column units, and each first column unit includes at least one column; All the second contact holes opened on the second region constitute a second hole array, the second hole array includes two or more columns, and the second contact holes in each column are arranged in a straight line in the first direction, wherein the columns in the second hole array are divided into at least two second column units, and each second column unit includes at least one column; The first column of cells in the first aperture array and the second column of cells in the second aperture array are arranged alternately.

3. The back contact battery according to claim 2, wherein: The number of first contact holes opened on all the first regions are equal and the size is the same. The first contact holes opened in each of the first regions are arranged in a row at equal intervals along the length direction of the first region and are centered in the width direction of the first region. The number and size of the second contact holes opened on all the second regions are equal, wherein the second contact holes opened in each of the second regions are arranged in a row at equal intervals along the length direction of the second region and are centered in the width direction of the second region.

4. The back contact battery according to claim 3, wherein: For any one of the first region and the second region, if the shape of the contact hole on the region is circular, let D represent the width of the region, d represent the diameter of the contact hole, L represent the distance between the centers of two adjacent contact holes on the same region, A represent the distance between the contact hole and the edge of the region, and B represent the distance between two adjacent contact holes on the same region, then A = (Dd) / 2, B = Ld and 0 ≤ |AB| ≤ 3d; For any one of the first region and the second region, if the shape of the contact hole on the region is rectangular, let D represent the width of the region, a represent the size of the contact hole in the length direction of the region, b represent the size of the contact hole in the width direction of the region, L represent the distance between the centers of two adjacent contact holes in the same region, A represent the distance between the contact hole and the edge of the region, and B represent the distance between two adjacent contact holes in the same region, then A = (Db) / 2, B = La and A / 2 ≤ B ≤ A.

5. The back contact battery according to claim 2, wherein: Each of the first column units includes one column, and each of the second column units includes one column; The first electrode includes a first gate line that corresponds one-to-one with a column in the first hole array, and each first gate line forms an ohmic contact with the first doped unit through a first contact hole in the column corresponding to it; The second electrode includes a second gate line corresponding to a column in the second hole array, and each second gate line forms an ohmic contact with the second type doped unit through a second contact hole in the column corresponding to it.

6. The back contact battery according to claim 2, wherein: Each of the first column units includes one column, and each of the second column units includes at least two columns; The first electrode includes a first gate line that corresponds one-to-one with a column in the first hole array, and each first gate line forms an ohmic contact with the first doped unit through a first contact hole in the column corresponding to it; The second electrode includes gate line units that correspond one-to-one with the second column units in the second hole array. Each gate line unit includes a second gate line corresponding to one column of the second column unit and a first bus gate line. The second gate line forms an ohmic contact with the second type doped unit through a second contact hole in its corresponding column. The second contact holes in other columns of the second column unit are connected to the second gate line through the first bus gate line.

7. The back contact battery according to claim 5 or 6, wherein: Both the first gate line and the second gate line are single, straight gate lines; or Each first gate line includes at least two first gate line segments arranged along the first direction and spaced apart by a first gap. The number of first gaps in each first gate line is the same, and the corresponding first gaps in all first gate lines are arranged in a straight line in a direction perpendicular to the first direction. The corresponding first gate line segments in all first gate lines constitute a first gate line group. Each second gate line includes at least two second gate line segments arranged along the first direction and spaced apart by a second gap. The number of second gaps in each second gate line is the same, and the corresponding second gaps in all second gate lines are arranged in a straight line in a direction perpendicular to the first direction. The second gaps and the first gaps are staggered. The corresponding second gate line segments in all second gate lines constitute a second gate line group.

8. The back contact battery according to claim 7, wherein, For the case where both the first gate line and the second gate line are a single, straight gate line: The first electrode further includes a second bus gate line, which is disposed on one side of the doped region in the first direction and connected to the ends of all the first gate lines; The second electrode further includes a third bus gate line, which is disposed on the other side of the doped region in the first direction and is connected to the ends of all the second gate lines.

9. The back contact battery according to claim 5 or 6, wherein, For the case where the first gate line includes a first gate line segment and the second gate line includes a second gate line segment: The first electrode further includes a fourth bus gate line corresponding to the first gate line group one by one. Each fourth bus gate line is connected to the first gate line segment in the corresponding first gate line group. For any fourth bus gate line, it is disposed on one side of the doped region in the first direction or disposed in one of the second gaps. The second electrode further includes a fifth bus gate line corresponding to each of the second gate line groups. Each fifth bus gate line is connected to the second gate line segment in the corresponding second gate line group. For any fifth bus gate line, it is disposed on one side of the doped region in the first direction or disposed in one of the first gaps.

10. The back contact battery according to claim 1, wherein: Both the first type of doped unit and the second type of doped unit are regular polygonal shapes; Each of the first regions is provided with a first contact hole located at the center of the first region, and each of the second regions is provided with a second contact hole located at the center of the second region. At least one side of any first type doped unit is connected to a second type doped unit, and at least one side of any second type doped unit is connected to a first type doped unit.

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