Back contact battery and photovoltaic module

Abstract

The invention provides a back contact battery, which comprises a semiconductor substrate, a first doping layer and a second doping layer, the main body part of the first doping layer and the main body part of the second doping layer are alternately distributed on one side of the backlight surface of the semiconductor substrate, and the conduction types of the first doping layer and the second doping layer are opposite; wherein a conductive connection structure is arranged between a part of the first doped layer and a part of the second doped layer, and wherein a single conductive connection structure comprises at least two side butt joint surfaces. The invention also provides a photovoltaic module. According to the back contact battery, the electric leakage channel contact area of the single conductive connection structure can be increased, and the effect of improving the hot spot effect is better.

Description

Technical Field

[0001] The present invention relates to the field of photovoltaic technology, and in particular to a back contact cell and a photovoltaic module. Background Art

[0002] A back-contact cell refers to a solar cell with no electrodes on the light-facing side of the cell, and both the positive and negative electrodes are arranged on the back-light side of the cell. This can reduce the shading of the electrodes to the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell. During the actual use of the back-contact battery, bird droppings, leaves, dust and other obstructions may fall onto the component, blocking the cell at the corresponding position. When the cell is blocked, the temperature will rise and produce a hot spot effect. If the temperature generated by the hot spot exceeds a certain temperature value, it will cause problems such as delamination of the photovoltaic module, burning of the back panel, and cracking of the glass, which will cause the entire solar cell to be scrapped, and in severe cases may cause a fire risk. However, existing back-contact batteries with anti-hot spot structures have problems such as excessive leakage loss and excessive local heating.

[0003] Therefore, there is a need to provide an improved back contact cell and photovoltaic module to overcome or reduce at least some of the disadvantages existing in the above-mentioned prior art. Summary of the invention

[0004] In a first aspect of the present invention, a back-contact cell is provided, wherein the back-contact cell comprises: a semiconductor substrate, a first doping layer and a second doping layer;

[0005] The main body of the first doping layer and the main body of the second doping layer are alternately distributed on the backlight side of the semiconductor substrate, and the first doping layer and the second doping layer have opposite conductivity types;

[0006] There is a conductive connection structure between a portion of the first doping layer and a portion of the second doping layer, and a single conductive connection structure includes at least two side abutting surfaces.

[0007] In the back-contact battery of the present invention, a conductive connection structure is arranged between a part of the first doped layer and a part of the second doped layer, so that a built-in diode with a lower reverse breakdown voltage can be formed at the electrical connection between the first doped layer and the second doped layer, which is beneficial for the back-contact battery to have a lower reverse breakdown voltage when it is shielded, thereby reducing the hot spot risk of the back-contact battery; at the same time, by arranging a single conductive connection structure to include at least two side docking surfaces, when the size of the single conductive connection structure is certain, the leakage channel contact area of ​​the single conductive connection structure can be increased to enhance the anti-hot spot function, and at the same time, the electrical connection points are dispersed to at least two sides, which can disperse the heat points, avoid local overheating, and improve the hot spot effect better.

[0008] Optionally, a spacing region is provided between the main body portion of the first doping layer and the main body portion of the second doping layer;

[0009] The first doping layer further includes an extension of the first doping layer, and the second doping layer further includes an extension of the second doping layer. The extension of the first doping layer and the extension of the second doping layer are electrically connected at the spacing region to form a conductive connection structure.

[0010] Optionally, the extension portion of the first doping layer and the extension portion of the second doping layer are overlapped and staggered.

[0011] Optionally, the extension portion of the second doping layer covers the extension portion of the first doping layer to achieve overlapping, and in the extension direction of the spacing region, the length of the extension portion of the second doping layer is greater than the length of the extension portion of the first doping layer.

[0012] Optionally, an end of the extension portion of the second doping layer extends to a junction between the spacing region and the main portion of the first doping layer.

[0013] Optionally, the extension portion of the second doping layer extends across the spacing region and extends such that a terminal end of the extension portion of the second doping layer is covered by the main portion of the first doping layer.

[0014] Optionally, a spacing region is provided between the main body portion of the first doping layer and the main body portion of the second doping layer;

[0015] The second doped layer further includes an extension of the second doped layer;

[0016] The extension portion of the second doping layer extends across the spacing region and extends such that a terminal end of the extension portion of the second doping layer is covered by the main portion of the first doping layer.

[0017] Optionally, the side butt joint surface has a bent structure;

[0018] The bending structure includes a plurality of connecting sections connected in a bending manner in a direction parallel to the backlight surface.

[0019] Optionally, each docking section has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1;

[0020] In the extension direction perpendicular to the bending structure, the bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1;

[0021] Among them, 0.00005≤T1 / δ1≤500000.

[0022] In a second aspect of the present invention, there is provided a photovoltaic assembly, comprising:

[0023] A battery string, wherein the battery string is formed by electrically connecting a plurality of the aforementioned back-contact batteries; and

[0024] Encapsulation layer, the encapsulation layer covers the surface of the back contact battery.

[0025] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Features, advantages, and exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals refer to like elements, and in which:

[0027] Figure 1 It is a partial schematic diagram of some components of a back contact battery according to an embodiment of the present invention, wherein two side docking surfaces are shown.

[0028] Figure 2 Is has Figure 1 The side butt joint of the back contact battery of one embodiment of the present invention is along the Figure 1 Schematic diagram of the cross-sectional structure in the X direction.

[0029] Figure 3 yes Figure 2 The back contact of the battery Figure 1 Schematic diagram of the cross-sectional structure in the Y direction.

[0030] Figure 4 It is a partial schematic diagram of some components of a back contact battery according to another embodiment of the present invention, wherein three side docking surfaces are shown.

[0031] Figure 5 yes Figure 4 The back contact of the battery Figure 1 Schematic diagram of the cross-sectional structure in the Y direction.

[0032] Figure 6 It is a partial schematic diagram of some components of a back contact battery according to another embodiment of the present invention, wherein five side docking surfaces are shown.

[0033] Figure 7 It is a partial schematic diagram of some components of a back contact battery according to another embodiment of the present invention, wherein seven side docking surfaces are shown.

[0034] Figure 8 It is a schematic diagram of the distribution relationship between the first doping layer and the second doping layer of the back contact battery according to an embodiment of the present invention.

[0035] Fig. 9 This is another schematic diagram of the distribution relationship between the first doping layer and the second doping layer of the back contact battery according to an embodiment of the present invention.

[0036] Fig.10 It is a partial schematic diagram of some components of a back contact battery according to an embodiment of the present invention, wherein three side docking surfaces are shown.

[0037] Fig.11 yes Figure 1 Schematic diagram of a single side docking surface.

[0038] Fig.12 Schematic diagrams of bending structures of different shapes. DETAILED DESCRIPTION

[0039] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0040] Various structural schematic diagrams according to embodiments of the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0041] In the context of the present invention, when a layer / element is referred to as being "on" another layer / element, the layer / element may be directly on the other layer / element, or there may be an intermediate layer / element between them. In addition, if a layer / element is "on" another layer / element in one orientation, then when the orientation is reversed, the layer / element may be "under" the other layer / element. In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] An embodiment of the present invention provides a back contact battery 100, wherein: Figure 1 and Figure 2 As shown, the back contact battery 100 includes: a semiconductor substrate 101, a first doping layer 200 and a second doping layer 300; the main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed on the backlight side of the semiconductor substrate 101, and the conductivity types of the first doping layer 200 and the second doping layer 300 are opposite; wherein a conductive connection structure 700 is provided between a portion of the first doping layer 200 and a portion of the second doping layer 300, and wherein a single conductive connection structure 700 includes at least two side docking surfaces 400.

[0045] In the back contact cell 100 of the embodiment of the present invention, by providing a conductive connection structure 700 between a portion of the first doping layer 200 and a portion of the second doping layer 300, a built-in diode with a lower reverse breakdown voltage can be formed at the electrical connection between the first doping layer 200 and the second doping layer 300, which is beneficial for the back contact cell 100 to have a lower reverse breakdown voltage when it is shielded, thereby reducing the risk of hot spots in the back contact cell 100; by configuring a single conductive connection structure 700 to include at least two side docking surfaces 400, on the one hand, when the size of a single conductive connection structure is certain, the contact area of ​​the leakage channel of the single conductive connection structure 700 can be increased to enhance the anti-hot spot function; on the other hand, dispersing the electrical connection points to at least two sides can disperse the heat points, avoid local overheating, and improve the effect of improving the hot spot effect. In the overall scheme design, this design can reduce the total number of conductive connection structures 700, thereby improving the hot spot effect while ensuring that the photovoltaic module has a higher photoelectric conversion efficiency in the forward voltage region. By increasing the number of side docking surfaces, the size of a single conductive connection structure 700 can be reduced while keeping the total leakage channel contact area of ​​the single conductive connection structure 700 unchanged or slightly increased, and the impact of the conductive connection structure 700 on the appearance can be reduced, so that the design space of the back contact battery 100 is larger. Therefore, a balance can be achieved between improving the hot spot effect and ensuring the photoelectric conversion efficiency by adjusting the size of the single conductive connection structure 700, the total number of conductive connection structures 700, the arrangement method, etc.

[0046] The conductive connection structure 700 is used to realize the electrical connection between a part of the first doped layer 200 and a part of the second doped layer 300, and is mainly used as an anti-hot spot structure, and can also be called an anti-hot spot structure or an anti-hot spot conductive connection structure. A single battery cell can have one or more conductive connection structures 700, wherein a single conductive connection structure 700 can include at least two side docking surfaces 400. A single "battery cell" can be a whole cell, a half cell, or a cell of other specifications. It can be understood that when a single battery cell has multiple conductive connection structures 700, all of the conductive connection structures 700 can each include at least two side docking surfaces 400, or only part of the conductive connection structures 700 can each include at least two side docking surfaces 400.

[0047] The embodiment of the present invention further provides a photovoltaic module (not shown in the figure), wherein the photovoltaic module comprises a battery string formed by electrically connecting the aforementioned back contact batteries 100 and an encapsulation layer covering the surface of the battery string. The photovoltaic module has similar effects to the aforementioned back contact batteries 100.

[0048] The back contact battery 100 according to the embodiment of the present invention will be described in more detail below with reference to the accompanying drawings.

[0049] The back contact cell 100 refers to a solar cell in which the light-facing side 111 of the cell has no electrode, and the positive electrode and the negative electrode are both arranged on the backlight side 112 of the cell. This can reduce the shading of the electrode to the cell, increase the short-circuit current of the cell, and improve the energy conversion efficiency of the cell.

[0050] The distribution relationship between the first doping layer 200 and the second doping layer 300 of the back contact cell 100 can be two kinds, respectively: Figure 8 and Fig. 9 It can be understood that, herein, "first doping layer" and "second doping layer" are only for the convenience of description, and the first doping layer 200 and the second doping layer 300 can be interchanged in terms of function and setting position.

[0051] Combine the following Figure 8 A back contact cell 100 according to an embodiment of the present application is described.

[0052] exist Figure 8 In the embodiment, the first doping layer 200 includes a main body 204 of the first doping layer, and the second doping layer 300 includes a main body 304 of the second doping layer. The main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed in strips. There is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer.

[0053] Specifically, Figure 8 , the main body 204 of the first doping layer includes only the strip-shaped portion 201 of the first doping layer. The main body 304 of the second doping layer includes only the strip-shaped portion 301 of the second doping layer. The spacing region 190 is formed between the strip-shaped portion 201 of the first doping layer and the strip-shaped portion 301 of the second doping layer. Here, the region where the strip-shaped portion 201 of the first doping layer is located is the first doping region 191, the region where the strip-shaped portion 301 of the second doping layer is located is the second doping region 192, and the spacing region 190 is formed between the first doping region 191 and the second doping region 192.

[0054] The first doping layer 200 may further include an extension portion 203 of the first doping layer, which extends from a local area of ​​the main portion 204 of the first doping layer toward the second doping layer 300 , that is, from a local area of ​​the strip portion 201 of the first doping layer toward the strip portion 301 of the second doping layer 300 .

[0055] The second doping layer 300 may further include an extension portion 303 of the second doping layer, which extends from a local area of ​​the main portion 304 of the second doping layer toward the first doping layer 200, that is, from a local area of ​​the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer.

[0056] It should be noted that the extension portion 203 of the first doping layer is usually formed integrally with the main body 204 of the first doping layer, that is, it is extended from a local area of ​​the main body 204 of the first doping layer toward the second doping layer 300. However, the extension portion 203 of the first doping layer can also be formed separately from the main body 204 of the first doping layer, that is, using an additional process, it is independent of the main body 204 of the first doping layer to form a conductive block, wherein the conductive block is structurally connected or partially stacked with the main body 204 of the first doping layer, and the materials can be the same or different, and the conductive type can be the same. The extension portion 303 of the second doping layer is similar to the extension portion 203 of the first doping layer, and will not be repeated here.

[0057] In this way, in the conductive connection structure 700 between a portion of the first doping layer 200 and a portion of the second doping layer 300, "a portion of the first doping layer" can be a portion of the main body 204 of the first doping layer, or the whole or a portion of the extension 203 of the first doping layer, and the "a portion of the second doping layer" can be a portion of the main body 304 of the second doping layer, or the whole or a portion of the extension 303 of the second doping layer.

[0058] Regarding the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, the first doping layer 200 and the second doping layer 300 may both be formed within the semiconductor substrate 101. Alternatively, the first doping layer 200 and the second doping layer 300 may both be formed on the semiconductor substrate 101. Alternatively, the first doping layer 200 is formed within the semiconductor substrate 101, and the second doping layer 300 is formed on the semiconductor substrate 101. Alternatively, the first doping layer 200 is formed on the semiconductor substrate 101, and the second doping layer 300 is formed within the semiconductor substrate 101.

[0059] Specifically, in the case where the first doping layer 200 and the second doping layer 300 are both formed within the semiconductor substrate 101, that is, the first doping layer 200 and the second doping layer 300 having a certain thickness exist within the semiconductor substrate 101, the conductive connection structure 700 having at least two side butt joints 400 may be formed by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300, or may be formed by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300 at a first position and butt jointing at a second position. Compared with the side butt joints formed in an overlapping manner, the reliability of the electrical connection at the side butt joints formed in an overlapping manner is higher, and a top-to-bottom butt joint may be formed between the top surface of the doping layer below and the bottom surface of the doping layer above, thereby being more conducive to improving the anti-hot spot effect. In the case where the first doping layer 200 and the second doping layer 300 are both formed on the semiconductor substrate 101, the conductive connection structure 700 having at least two side butt joints 400 may be formed by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300 (such as Figures 1 to 3 As shown), it can also be formed by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300 at a first position and butting at a second position (as shown in Figure 6 and Figure 7 As shown). In the case where the first doping layer 200 is formed inside the semiconductor substrate 101 and the second doping layer 300 is formed on the semiconductor substrate 101, the height of the semiconductor substrate 101 corresponding to the main part 204 of the first doping layer 200 is higher than the height of the semiconductor substrate 101 corresponding to the main part 304 of the second doping layer 300, and the conductive connection structure 700 having at least two side butt joint surfaces 400 can be formed by overlapping the entire or a portion of the extension part 303 of the second doping layer and a portion of the first doping layer, or can be formed by overlapping the entire or a portion of the extension part 303 of the second doping layer and a portion of the first doping layer at a first position and butting at a second position. There can be one or more of the aforementioned first position and second position.

[0060] Regarding the specific structure of the spacing region 190 , in the back contact battery 100 of the embodiment of the present application, the spacing region 190 may be a spacing region disconnected between the main body 204 of the first doping layer and the main body 304 of the second doping layer.

[0061] Regarding the number of side interface surfaces 400 of a single conductive connection structure 700, a single conductive connection structure 700 may have at least two side interface surfaces 400, for example, a single conductive connection structure 700 may have two side interface surfaces 400 (see Figure 1 ), three side butt joints 400 (see Figure 4), four side butt joints 400, five side butt joints 400 (see Figure 6 ), six side butt joints 400, or even up to nine side butt joints 400 (see Figure 7 )wait.

[0062] Regarding the contact mode between a portion of the first doping layer 200 and a portion of the second doping layer 300, a portion of the first doping layer 200 and a portion of the second doping layer 300 may be in direct contact with each other to form a conductive connection structure 700; a portion of the first doping layer 200 and a portion of the second doping layer 300 may also be in indirect contact with each other to form a conductive connection structure 700, that is, other layer structures may be provided between a portion of the first doping layer 200 and a portion of the second doping layer 300 as needed, and it is sufficient that a portion of the first doping layer 200 and a portion of the second doping layer 300 can be electrically connected.

[0063] The formation position of the conductive connection structure 700 may be the spacing region 190, the first doping region, the second doping region, the spacing region 190 and the first doping region, and the spacing region 190 and the second doping region. The formation position of the side interface 400 in a single conductive connection structure 700 may be the spacing region 190, the first doping region 191, the second doping region 192, the junction of the spacing region 190 and the first doping region 191 (also referred to as the junction of the spacing region 190 and the strip-shaped portion 201 of the first doping layer), and the junction of the spacing region 190 and the second doping region 192 (also referred to as the junction of the spacing region 190 and the strip-shaped portion 301 of the second doping layer).

[0064] In some implementations, reference Figures 1 to 7 , a spacing region 190 is provided between the main body 204 of the first doping layer and the main body 304 of the second doping layer; the first doping layer 200 further includes an extension 203 of the first doping layer, and the second doping layer 300 further includes an extension 303 of the second doping layer, and the extension 203 of the first doping layer and the extension 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein a single conductive connection structure 700 includes at least two side butt surfaces 400. Figure 8 There is a spacing region 190 between the strip portion 201 of the first doping layer and the strip portion 301 of the second doping layer; the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein a single conductive connection structure 700 includes at least two side docking surfaces 400.

[0065] When the extension 203 of the first doping layer and the extension 303 of the second doping layer are arranged in an overlapping manner at the spacing region 190, the single conductive connection structure 700 includes at least two side butt surfaces 400. The conductivity type of the first doping layer 200 can be N-type, and the conductivity type of the second doping layer 300 is P-type; or, the conductivity type of the first doping layer 200 can also be P-type, and the conductivity type of the second doping layer 300 is N-type. Optionally, the doping layer at the top is an N-type doping layer, and the doping layer at the bottom is a P-type doping layer. That is, when all or part of the extension 203 of the first doping layer is above all or part of the extension 303 of the second doping layer, the first doping layer 200 is an N-type doping layer, and the conductivity type of the second doping layer is a P-type doping layer; and when all or part of the extension 303 of the second doping layer is above all or part of the extension 203 of the first doping layer, the second doping layer is an N-type doping layer, and the conductivity type of the first doping layer 200 is a P-type doping layer.

[0066] The width of the spacing region 190 may range from 10 to 5000 micrometers. The width of the spacing region 190 is the dimension of the spacing region 190 in a direction perpendicular to the extension direction of the spacing region 190. The width of the spacing region 190 may be, for example, 10 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 2000 micrometers, 3000 micrometers, or 5000 micrometers.

[0067] The width of the conductive connection structure 700 may range from 20 to 2000 micrometers. The width of the conductive connection structure 700 is the dimension of the conductive connection structure 700 in a direction perpendicular to the extension direction of the spacing region 190. The width of the conductive connection structure 700 may be, for example, 20 micrometers, 50 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, or 2000 micrometers.

[0068] The length of the conductive connection structure 700 may range from 50 to 1000 micrometers. The length of the conductive connection structure 700 is the dimension of the conductive connection structure 700 in the extension direction parallel to the spacing region 190. The length of the conductive connection structure 700 may be, for example, 50 micrometers, 80 micrometers, 100 micrometers, 300 micrometers, 500 micrometers, or 1000 micrometers.

[0069] In order to balance the anti-hot spot performance and battery efficiency, the sum of the width of the conductive connection structure 700 and the length of the conductive connection structure 700 can be in the range of 100-3000 microns. The sum of the width of the conductive connection structure 700 and the length of the conductive connection structure 700 can be, for example, 100 microns, 500 microns, 1000 microns, 2000 microns, and 3000 microns. By limiting the sum of the width of the conductive connection structure 700 and the length of the conductive connection structure 700 to the aforementioned orientation, it is possible to avoid the length and width of the conductive connection structure 700 being too large, resulting in an excessively large leakage contact area, which affects the battery efficiency, so that the anti-hot spot performance and the battery conversion efficiency can achieve a better matching effect.

[0070] The length of the extension portion 203 of the first doping layer may range from 50 to 3000 microns. The length of the extension portion 203 of the first doping layer is the dimension of the extension portion 203 of the first doping layer in the extension direction parallel to the spacing region 190. The length of the extension portion 203 of the first doping layer may be, for example, 50 microns, 100 microns, 500 microns, 1000 microns, 2000 microns, or 3000 microns.

[0071] The width of the extension portion 203 of the first doping layer may range from 50 to 3000 microns. The length of the extension portion 203 of the first doping layer is the dimension of the extension portion 203 of the first doping layer in the extension direction perpendicular to the spacing region 190. The width of the extension portion 203 of the first doping layer may be, for example, 50 microns, 100 microns, 500 microns, 1000 microns, 2000 microns, or 3000 microns.

[0072] The length of the extension portion 303 of the second doping layer may range from 50 to 3000 microns. The length of the extension portion 303 of the second doping layer is the dimension of the extension portion 303 of the second doping layer in the extension direction parallel to the spacing region 190. The length of the extension portion 303 of the second doping layer may be, for example, 50 microns, 100 microns, 500 microns, 1000 microns, 2000 microns, or 3000 microns.

[0073] The width of the extension portion 303 of the second doping layer may range from 50 to 3000 microns. The length of the extension portion 303 of the second doping layer is the dimension of the extension portion 303 of the second doping layer in the extension direction perpendicular to the spacing region 190. The width of the extension portion 303 of the second doping layer may be, for example, 50 microns, 100 microns, 500 microns, 1000 microns, 2000 microns, or 3000 microns.

[0074] Through experimental tests, by making a single conductive connection structure 700 include at least two side butt joints 400, the number of anti-hot spot structures is reduced from 1500-2000 to 500-800, and the ratio of the total area of ​​the side butt joints 400 to the area of ​​the back contact battery 100 is (10 -9 -10 -3 ):1.

[0075] In some embodiments, the extension 203 of the first doping layer and the extension 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein the extension 203 of the first doping layer and the extension 303 of the second doping layer are staggered and overlapped. In this case, a single conductive connection structure 700 includes two side butt surfaces 400. Staggered overlap of the extension 203 of the first doping layer and the extension 303 of the second doping layer has a low processing difficulty and is conducive to practical application, so that the contact area of ​​the leakage channel of the single conductive connection structure 700 can be increased without affecting the processing efficiency too much. "Staggered overlap" at the spacing region means that at the spacing region, a portion of the end of the extension 203 of the first doping layer and a portion of the end of the extension 303 of the second doping layer are overlapped. Taking the staggered overlap of the extension 303 of the second doping layer above the extension 203 of the first doping layer as an example, among the three side surfaces of the end of the extension 203 of the first doping layer, only part of the area of ​​two side surfaces is covered by the extension 303 of the second doping layer. From the projection on the semiconductor substrate, the projection of the end of the extension 203 of the first doped layer on the semiconductor substrate and the projection of the end of the extension 303 of the second doped layer on the semiconductor substrate only partially overlap. Here, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. Assume that the length of the extension 203 of the first doped layer in its extension direction is m1, and the width perpendicular to its extension direction is n1; the length of the extension 303 of the second doped layer in its extension direction is m2, and the width perpendicular to its extension direction is n2; wherein, m1 and m2 can be the same or different; n1 and n2 can be the same or different. Figure 1 The figure shows a structure of staggered overlap in the spacing region 190, wherein a single conductive connection structure 700 includes two side docking surfaces 400, namely a first side docking surface 401 and a second side docking surface 402; wherein the first side docking surface 401 and the second side docking surface 402 are both formed between an extension portion 203 of the first doping layer and an extension portion 303 of the second doping layer, and wherein an extension direction of the first side docking surface 401 is parallel to an extension direction of the spacing region 190, while an extension direction of the second side docking surface 402 is perpendicular to an extension direction of the spacing region 190. Figure 2 Is has Figure 1 The side butt joint 400 is along the back contact of the battery 100 Figure 1 Schematic diagram of the cross-sectional structure in the X direction. Figure 3 along Figure 1 Schematic diagram of the cross-sectional structure in the Y direction. Figure 2 and Figure 3 It can be seen that the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are staggered and overlapped at the spacing region 190 , thereby forming a conductive connection structure 700 including two side butt surfaces 400 .

[0076] It should be understood that, in this article, when describing the directional relationship structure of "parallel to", "perpendicular to", etc., it includes both precise "parallel to", "perpendicular to", etc., as well as generally, basically, and approximately "parallel to", "perpendicular to", etc.

[0077] The “extension direction of the spacing region” refers to the extension direction of the portion that defines the main portion 204 of the first doping layer and the main portion 304 of the second doping layer of the spacing region 190. Figure 8 There is only one direction of the spacing region 190, which defines the extension direction of the main body 204 of the first doped layer, i.e., the strip portion 201 of the first doped layer, and the main body 304 of the second doped layer, i.e., the strip portion 301 of the second doped layer, of the spacing region 190.

[0078] In other embodiments, the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein the extension portion 303 of the second doping layer covers the extension portion 203 of the first doping layer to achieve overlap, and in the extension direction of the spacing region 190, the length of the extension portion 303 of the second doping layer is greater than the length of the extension portion 203 of the first doping layer. In this case, a single conductive connection structure 700 includes three or more side butt surfaces 400. The extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are overlapped, and since it is necessary to ensure that the length of the extension portion 303 of the second doping layer is greater than the length of the extension portion 203 of the first doping layer and the two are overlapped, the processing difficulty is increased compared to the staggered overlap, but the effect of increasing the contact area of ​​the leakage channel of the single conductive connection structure 700 is better, and the effect of improving the hot spot effect is better. "Overlapping" in the spacing region 190 means that at the spacing region 190, a local area of ​​the end of the extension portion 303 of the second doping layer covers over the entire area of ​​the end of the extension portion 203 of the first doping layer to form an overlap, and the three sides of the end of the extension portion 203 of the first doping layer are covered by the extension portion 303 of the second doping layer. From the projection on the semiconductor substrate, the projection of the end of the extension portion 303 of the second doping layer on the semiconductor substrate completely covers the projection of the end of the extension portion 203 of the first doping layer on the semiconductor substrate. Similar to the previous text, the specific length ratio of the end to the entire extension portion is not limited and can be adjusted as needed. Assume that the length of the extension portion 203 of the first doping layer in its extension direction is m1, and the width perpendicular to its extension direction is n1; the length of the extension portion 303 of the second doping layer in its extension direction is m2, and the width perpendicular to its extension direction is n2; wherein, m1 and m2 can be the same or different; n2>n1. Figure 4 The structure of overlapping in the spacing region 190 is shown in the figure, wherein a single conductive connection structure 700 includes three side butt joints 400, namely a first side butt joint 401, a second side butt joint 402, and a third side butt joint 403; wherein the first side butt joint 401, the second side butt joint 402, and the third side butt joint 403 are all formed between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer, and wherein the extension direction of the first side butt joint 401 is parallel to the extension direction of the spacing region 190, and the extension directions of the second side butt joint 402 and the third side butt joint 403 are perpendicular to the extension direction of the spacing region 190. Figure 4 The side butt joint 400 is along the back contact of the battery 100 Figure 4 The cross-sectional structure in the X direction is the same as Figure 2 . Figure 5 along Figure 4 Schematic diagram of the cross-sectional structure in the Y direction. Figure 2 and Figure 5 It can be seen that the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer overlap and cover at the spacing region 190 , thereby forming a conductive connection structure 700 including three side contact surfaces 400 .

[0079] Further, the end of the extension portion 303 of the second doped layer extends to the junction of the spacing region 190 and the main body 204 of the first doped layer. In this case, the single conductive connection structure 700 includes more than three side butt surfaces 400. In the case of overlapping, by extending the end of the extension portion 303 of the second doped layer to the junction of the spacing region 190 and the main body 204 of the first doped layer, the number of side butt surfaces 400 of the single conductive connection structure 700 can be further increased, thereby further increasing the contact area of ​​the leakage channel of the single conductive connection structure 700, and further improving the effect of the hot spot effect. Figure 6 1 shows a structure in which the spacing region 190 overlaps and the end of the extension portion 303 of the second doping layer extends to the junction of the spacing region 190 and the main body 204 of the first doping layer, wherein the single conductive connection structure 700 includes five side docking surfaces 400, namely a first side docking surface 401, a second side docking surface 402, a third side docking surface 403, a fourth side docking surface 404, and a fifth side docking surface 405; wherein the first side docking surface 401, the second side docking surface 402, and the third side docking surface 403 are the second doping The extension portion 303 of the layer is covered and overlapped to form above the extension portion 203 of the first doped layer, and the fourth side docking surface 404 and the fifth side docking surface 405 are formed by docking between the end of the extension portion 303 of the second doped layer and the main body 204 of the first doped layer, and wherein the extension directions of the first side docking surface 401, the fourth side docking surface 404 and the fifth side docking surface 405 are parallel to the extension direction of the spacing region 190, and the extension directions of the second side docking surface 402 and the third side docking surface 403 are perpendicular to the extension direction of the spacing region 190.

[0080] Furthermore, the extension portion 303 of the second doping layer extends across the spacing region 190 and extends such that the end of the extension portion 303 of the second doping layer is covered by the main portion 204 of the first doping layer. In this case, the single conductive connection structure 700 includes more than five side abutting surfaces 400 . In the case of overlapping, by extending the extension portion 303 of the second doping layer across the spacing area 190 and extending it so that the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer, the number of side docking surfaces 400 possessed by the single conductive connection structure 700 can be further increased, thereby further increasing the leakage channel contact area of ​​the single conductive connection structure 700, and further improving the effect of the hot spot effect; at the same time, since the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer to form a stacked structure, in the subsequent metallization process, the first electrode corresponding to the main body 204 of the first doping layer and the extension portion 303 of the second doping layer (especially the portion of the extension portion 303 of the second doping layer constituting the stacked structure) will obviously be separated by the main body 204 of the first doping layer. Therefore, when printing the first electrode, there is no need to consider the relative position of the first electrode and the stacked structure, and there is no need to consider the alignment problem, so that the processing efficiency is higher. Figure 7 The structure of overlapping the spacing region 190 and the doping region is shown in the figure, wherein the single conductive connection structure 700 includes nine side docking surfaces 400, namely the first side docking surface 401, the second side docking surface 402, the third side docking surface 403, the fourth side docking surface 404, the fifth side docking surface 405, the sixth side docking surface 406, the seventh side docking surface 407, the eighth side docking surface 408, and the ninth side docking surface 409; wherein the first side docking surface 401, the second side docking surface 402, and the third side docking surface 403 are formed by overlapping the extension portion 303 of the second doping layer on the top of the extension portion 203 of the first doping layer, and the fourth side docking surface 404, the fifth side docking surface 405, and the sixth side docking surface 406 are the main bodies of the first doping layer The first part of the main portion 204 is formed by overlapping and covering the first part of the end of the extension portion 303 of the second doping layer, and the seventh side docking surface 407, the eighth side docking surface 408 and the ninth side docking surface 409 are formed by overlapping and covering the second part of the main portion 204 of the first doping layer above the second part of the end of the extension portion 303 of the second doping layer, and wherein the extension directions of the first side docking surface 401, the fourth side docking surface 404 and the seventh side docking surface 407 are parallel to the extension direction of the spacing region 190, and the extension directions of the second side docking surface 402, the third side docking surface 403, the fifth side docking surface 405, the sixth side docking surface 406, the eighth side docking surface 408 and the ninth side docking surface 409 are perpendicular to the extension direction of the spacing region 190.

[0081] It can be understood that when the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are staggered and overlapped in the spacing region 190, the end of the extension portion 303 of the second doping layer can be further extended to the junction of the spacing region 190 and the main body 204 of the first doping layer, or the extension portion 303 of the second doping layer can be further extended across the spacing region 190 and extended so that the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer. In this example, compared with the overlapping in the spacing region 190, the number of side butt surfaces 400 of the single conductive connection structure 700 increases less, the effect of increasing the contact area of ​​the leakage channel of the single conductive connection structure 700 is weaker, and the effect of improving the hot spot effect is weaker.

[0082] In some other implementations, reference Fig.10 , there is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer; the second doping layer 300 also includes an extension 303 of the second doping layer; the extension 303 of the second doping layer extends across the spacing region 190 and extends such that the end of the extension 303 of the second doping layer is covered by the main body 204 of the first doping layer. In this case, the single conductive connection structure 700 includes three side butt joints 400. Figure 8 The first doping layer only includes the strip portion 201 of the first doping layer, and the second doping layer 300 includes the strip portion 301 of the second doping layer and the extension portion 303 of the second doping layer; there is a spacing region 190 between the strip portion 201 of the first doping layer and the strip portion 301 of the second doping layer; and the extension portion 303 of the second doping layer extends across the spacing region 190 and extends so that the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer. In this implementation, since it is only necessary to set an extension portion in the second doping layer 300, the processing difficulty can be reduced, which is beneficial to practical application, and the contact area of ​​the leakage channel of the single conductive connection structure 700 can be increased without affecting the processing efficiency too much; at the same time, since the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer to form a stacked structure, in the subsequent metallization process, the first electrode corresponding to the main body 204 of the first doping layer and the extension portion 303 of the second doping layer (especially the portion of the extension portion 303 of the second doping layer constituting the stacked structure) will obviously be separated by the main body 204 of the first doping layer. Therefore, when printing the first electrode, there is no need to consider the relative position of the first electrode and the stacked structure, and there is no need to consider the alignment problem, so that the processing efficiency is higher. Fig.10, a structure of overlapping in doped regions is shown, wherein a single conductive connection structure 700 includes three side butt joints, namely a first side butt joint 401, a second side butt joint 402 and a third side butt joint 403; wherein the first side butt joint 401, the second side butt joint 402 and the third side butt joint 403 are all formed between a main body 204 of the first doped layer and an extension portion 303 of the second doped layer, and wherein an extension direction of the first side butt joint 401 is parallel to an extension direction of the spacing region 190, while an extension direction of the second side butt joint 402 and the third side butt joint 403 is perpendicular to an extension direction of the spacing region 190.

[0083] Combine the following Fig. 9 A back contact cell 100 according to an embodiment of the present application is described.

[0084] exist Fig. 9 In the embodiment, the first doping layer 200 includes a main body 204 of the first doping layer, and the second doping layer 300 includes a main body 304 of the second doping layer. The main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately distributed in a forked shape. There is a spacing region 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer.

[0085] Specifically, Fig. 9 In the embodiment, the main body 204 of the first doping layer includes a strip portion 201 of the first doping layer and a connecting portion 202 of the first doping layer, wherein the connecting portion 202 of the first doping layer is used to connect multiple strip portions 201 of the first doping layer. The second doping layer 300 includes a strip portion 301 of the second doping layer and a connecting portion 302 of the second doping layer, wherein the connecting portion 302 of the second doping layer is used to connect multiple strip portions 301 of the second doping layer. The region where the strip portion 201 of the first doping layer is located is the first doping region 191, the region where the strip portion 301 of the second doping layer is located is the second doping region 192, the region where the connecting portion 202 of the first doping layer is located is the third doping region 193, and the region where the connecting portion 302 of the second doping layer is located is the fourth doping region 194. In this case, the spacing region 190 can be: formed between the strip portion 201 of the first doping layer and the strip portion 301 of the adjacent second doping layer, that is, between the first doping region 191 and the second doping region 192; formed between the strip portion 201 of the first doping layer and the connecting portion 302 of the adjacent second doping layer, that is, between the first doping region 191 and the fourth doping region 194; formed between the connecting portion 202 of the first doping layer and the strip portion 301 of the adjacent second doping layer, that is, between the third doping region 193 and the second doping region 192.

[0086] As for the “extension direction of the spacing region”, it is the extension direction of the portion that defines the main portion 204 of the first doping layer and the main portion 304 of the second doping layer of the spacing region 190. Fig. 9 In the embodiment, there are spacer regions 190 in multiple directions, and for a certain spacer region 190, its extension direction is the extension direction of the part of the main body 204 of the first doping layer and the part of the main body 304 of the second doping layer that define the spacer region 190. For example, at mark 901, the extension direction of the spacer region 190 is the extension direction of the connection part 202 of the first doping layer and the extension direction of the end of the strip part 301 of the second doping layer; at mark 902, the extension direction of the spacer region 190 is the extension direction of the strip part 201 of the first doping layer and the extension direction of the strip part 301 of the second doping layer; at mark 903, the extension direction of the spacer region 190 is the extension direction of the connection part 302 of the second doping layer and the extension direction of the end of the connection part 202 of the first doping layer.

[0087] The first doping layer 200 may further include an extension portion 203 of the first doping layer, the extension portion 203 of the first doping layer extending from a local area of ​​the main body portion 204 of the first doping layer toward the second doping layer 300, that is, extending from the strip portion 201 of the first doping layer, or the connecting portion 202 of the first doping layer toward the second doping layer 300. Specifically, the extension portion 203 of the first doping layer extends from a local area of ​​the strip portion 201 of the first doping layer toward the strip portion 301 of the second doping layer or the connecting portion 302 of the second doping layer, or extends from the entire or local area of ​​the connecting portion 202 of the first doping layer toward the strip portion 301 of the second doping layer.

[0088] The second doping layer 300 may further include an extension portion 303 of the second doping layer, and the extension portion 303 of the second doping layer extends from a local area of ​​the main body portion 304 of the second doping layer toward the first doping layer 200, that is, extends from the strip portion 301 of the second doping layer, or the connecting portion 302 of the second doping layer toward the first doping layer 200. Specifically, the extension portion 303 of the second doping layer extends from a local area of ​​the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer or the connecting portion 202 of the first doping layer, or extends from the entire or local area of ​​the connecting portion 302 of the second doping layer toward the strip portion 201 of the first doping layer.

[0089] and Figure 8 similar, Fig. 9The extension portion 203 of the first doping layer is usually formed integrally with the main body portion 204 of the first doping layer, but the extension portion 203 of the first doping layer can also be formed separately from the main body portion 204 of the first doping layer. The extension portion 303 of the second doping layer is similar to the extension portion 203 of the first doping layer, and will not be described in detail here.

[0090] In this way, in the conductive connection structure 700 between a part of the first doping layer 200 and a part of the second doping layer 300, "a part of the first doping layer" can be a part of the strip portion 201 of the first doping layer, or the whole or a part of the connecting portion 202 of the first doping layer, or the whole or a part of the extending portion 203 of the first doping layer; "a part of the second doping layer" can be a part of the strip portion 301 of the second doping layer, or the whole or a part of the connecting portion 302 of the second doping layer, or the whole or a part of the extending portion 303 of the second doping layer.

[0091] The positions of the first doped layer 200 and the second doped layer 300 relative to the semiconductor substrate 101, the specific structure of the spacing region 190, the number of side docking surfaces 400 of a single conductive connection structure 700, the contact method between a portion of the first doped layer 200 and a portion of the second doped layer 300, and the formation position of the conductive connection structure 700 are similar to those described above and will not be elaborated here.

[0092] In some implementations, reference Figures 1 to 7 , a spacing region 190 is provided between the main body 204 of the first doping layer and the main body 304 of the second doping layer; the first doping layer 200 further includes an extension 203 of the first doping layer, and the second doping layer 300 further includes an extension 303 of the second doping layer, and the extension 203 of the first doping layer and the extension 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein a single conductive connection structure 700 includes at least two side butt surfaces 400. Fig. 9 There are multiple spacing regions 190 , and the conductive connection structure 700 can be formed in one or more of the multiple spacing regions 190 as needed.

[0093] In some embodiments, the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, and wherein the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are staggered and overlapped. In this case, a single conductive connection structure 700 includes two side butt surfaces 400. The technical effect is similar to the above, and will not be repeated here.

[0094] In other embodiments, the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected at the spacing region 190 to form a conductive connection structure 700, wherein the extension portion 303 of the second doping layer covers the extension portion 203 of the first doping layer to achieve overlap, and in the extension direction of the spacing region 190, the length of the extension portion 303 of the second doping layer is greater than the length of the extension portion 203 of the first doping layer. In this case, a single conductive connection structure 700 includes three or more side butt surfaces 400. The technical effect is similar to the above, and will not be repeated here.

[0095] Further, the end of the extension portion 303 of the second doping layer extends to the junction of the spacing region 190 and the main body portion 204 of the first doping layer. In this case, the single conductive connection structure 700 includes more than three side contact surfaces 400. The technical effect is similar to the above, and will not be repeated here.

[0096] Further, the extension portion 303 of the second doping layer extends across the spacing region 190 and extends such that the end of the extension portion 303 of the second doping layer is covered by the main body portion 204 of the first doping layer. In this case, the single conductive connection structure 700 includes more than five side butt surfaces 400. The technical effect is similar to the above, and will not be repeated here.

[0097] Similarly, when the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are staggered and overlapped in the spacing region 190, the end of the extension portion 303 of the second doping layer can be further extended to the junction of the spacing region 190 and the main body 204 of the first doping layer, or the extension portion 303 of the second doping layer can be further extended across the spacing region 190 and extended so that the end of the extension portion 303 of the second doping layer is covered by the main body 204 of the first doping layer.

[0098] In some embodiments, in the back contact battery 100 of the embodiment of the present invention, the side butt joint surface 400 has a bent structure 500. In other words, the side butt joint surface 400 is not a flat surface. In the back contact battery 100 of the embodiment of the present invention, compared with the butt joint surface of the flat structure, the side butt joint surface 400 with the bent structure 500 can increase the contact area of ​​the leakage channel of a single side butt joint surface 400, effectively reduce the total number of anti-hot spot structures, and minimize the loss of battery conversion efficiency caused by PN region contact while improving the hot spot effect.

[0099] Specifically, in the direction parallel to the backlight surface 112, the single side butt joint surface 400 has a bending and unfolding length L (not shown in the figure), an end straight length D (see Fig.11), wherein L>1.001D. By limiting the relationship between the bending expansion length L and the end straight length D to L>1.001D, it can be ensured that the side butt surface 400 forms a bend.

[0100] In some embodiments, under the 10-micron step measurement condition, L≥1.05D, for example, L is 1.05D, 1.08D, 1.10D, 1.20D. By setting L≥1.05D, it can be further ensured that the side docking surface 400 has a bent structure. Considering that it may be difficult or too complicated to completely measure a side docking surface in actual applications, the size relationship between L and D can be determined under the 10-micron step measurement condition. The 10-micron step measurement condition is to select one or more local sections with a straight line length of 10 microns from the entire side docking surface, and the end straight line length D of the one or more local sections is 10 microns. The bending expansion length L of the bending structure of the one or more local sections is measured, thereby directly obtaining or averaging the size relationship between L and D.

[0101] In a preferred embodiment, under the condition of 1 micron step measurement, L≥1.2D, for example, L is 1.2D, 1.4D, 1.5D, 1.8D, 5D. By setting L≥1.2D, it can be ensured that the bent structure of the side docking surface 400 can greatly increase the leakage channel contact area of ​​a single side docking surface 400, effectively prevent the back contact cell 100 from burning due to local heat concentration, effectively reduce the hot spot risk of the back contact cell 100 and the photovoltaic module including the back contact cell 100, and at the same time effectively reduce the total number of side docking surfaces 400. Usually, L≤800D, for example, L is 800D, 600D, 200D, 50D, 10D. When L exceeds the aforementioned range, it will cause excessive etching difficulty, affecting production efficiency.

[0102] The value range of D may be 10-3000 micrometers, for example, D is 10 micrometers, 100 micrometers, 500 micrometers, 1000 micrometers, 1500 micrometers, 2500 micrometers, or 3000 micrometers.

[0103] The value range of L may be 50-8000 micrometers, for example, 50 micrometers, 150 micrometers, 650 micrometers, 1500 micrometers, 2500 micrometers, 3000 micrometers, 5000 micrometers, and 8000 micrometers.

[0104] For the “direction parallel to the backlight surface”, take the case where the backlight surface 112 of the semiconductor substrate 101 is on the upward side as an example, for example Figure 2In the upper part, the direction of the backlight surface 112 can be considered to be substantially horizontal, and the side docking surface 400 is a surface perpendicular to the horizontal direction or having a certain angle with the horizontal direction. The surface has two first vertical sides perpendicular to the horizontal direction or having a certain angle with the horizontal direction, and two second horizontal sides substantially parallel to the horizontal direction. In this article, "the direction parallel to the backlight surface 112" refers to the extension direction of the second horizontal side, also referred to as "the extension direction of the side docking surface" and "the extension direction of the bending structure". In this way, the bending expansion length L and the end straight line length D are respectively discussing the bending expansion length and the end straight line length of the second horizontal side. For example, in Figure 4 In the example shown, there are three side butt joint surfaces 400, each of which has a direction parallel to the backlight surface 112, an extension direction of the side butt joint surface 400, and an extension direction of the bending structure 500. Specifically, the direction parallel to the backlight surface 112, the extension direction of the side butt joint surface 400, and the extension direction of the bending structure 500 of the second side butt joint surface 402 and the third side butt joint surface 403 are Figure 4 The left and right directions of the first side butt joint surface 401 are parallel to the backlight surface 112, the extending direction of the side butt joint surface 400, and the extending direction of the bending structure 500 are specifically Figure 4 Up and down direction.

[0105] The bending structure 500 may be any structure that can make the side butt joint surface 400 no longer a flat surface. The exemplary structure of the bending structure 500 is described in detail below in conjunction with the accompanying drawings.

[0106] In some embodiments, the bending structure 500 includes a plurality of connecting sections 510 connected in a bending manner in a direction parallel to the backlight surface 112, such as Fig.11 and Fig.12 By configuring the bending structure 500 to include a plurality of docking sections 510 connected in a bent manner, it can be ensured that the presence of the bending structure 500 can greatly increase the contact area of ​​the leakage channel of a single side docking surface 400, effectively prevent local overheating of the back contact battery 100, and effectively reduce the total number of side docking surfaces 400.

[0107] In the bending structure 500, a section having a complete protrusion alone is referred to as a "joint section".

[0108] refer to Fig.11 and Fig.12 Each docking section 510 may have a protrusion (not numbered in the figure), and the protrusion may have one or more of an arc shape, a square shape, a trapezoidal shape, a triangular shape, and an irregular shape.

[0109] Herein, when describing a certain shape, it includes both the standard shape and similar shapes that are substantially similar to the shape, for example, an arc shape includes a standard arc shape and a substantially arc shape, a square shape includes a standard square shape and a substantially square shape, a trapezoidal shape includes a standard trapezoidal shape and a substantially trapezoidal shape, and a triangular shape includes a standard triangular shape and a substantially triangular shape. For a special-shaped shape, it is an irregular shape that is greatly different from a standard common regular shape and cannot be classified.

[0110] The protrusions of the multiple docking sections 510 in a single bending structure 500 may have the same shape, and the protrusions may have the same protrusion direction. Alternatively, the protrusions of the multiple docking sections 510 in a single bending structure 500 may have different shapes, and the protrusions may have the same protrusion direction. The “protrusion direction of the protrusion” is substantially perpendicular to the extension direction of the bending structure 500.

[0111] exist Fig.12 a), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 respectively have an arc shape, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 includes an arc-shaped protrusion and an arc-shaped recessed portion located on both sides of the arc-shaped protrusion, that is, the docking section 510 is a section located between the vertices of two adjacent arc-shaped recessed portions.

[0112] exist Fig.12 b), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 respectively have an arc shape, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 only includes arc-shaped protrusions, that is, the docking section 510 is a section located between the intersection points of two adjacent arc-shaped protrusions.

[0113] exist Fig.12 c), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 have a square shape respectively, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 includes a square protrusion and square recessed portions located on both sides of the square protrusion, that is, the docking section 510 is a section located between the midpoints of the top edges of two adjacent square recessed portions.

[0114] exist Fig.12 d), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 respectively have a trapezoidal shape, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 only includes trapezoidal protrusions, that is, the docking section 510 is a section located between the intersection points of two adjacent trapezoidal protrusions.

[0115] exist Fig.12e), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 respectively have a trapezoidal shape, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 includes a trapezoidal protrusion and square recessed portions located on both sides of the trapezoidal protrusion, that is, the docking section 510 is a section located between the midpoints of the top edges of two adjacent square recessed portions.

[0116] exist Fig.12 f), in the bending structure 500, the multiple protrusions of the multiple docking sections 510 respectively have a triangular shape, and the protruding directions of the multiple protrusions are the same, wherein the docking section 510 only includes triangular protrusions, that is, the docking section 510 is a section located between the intersection points of two adjacent triangular protrusions.

[0117] exist Fig.12 g) and Fig.12 h), in the bending structure 500, the plurality of protrusions of the plurality of docking sections 510 respectively have irregular shapes, wherein the docking section 510 includes a section between the vertices or top edge midpoints of two recessed sections located on both sides of a protrusion.

[0118] exist Fig.12 i), in the bending structure 500, the protrusions of some docking sections 510 have an arc shape, and the protrusions of other docking sections 510 have a square shape, and the protruding directions of the multiple protrusions are the same.

[0119] exist Fig.12 j), in the bending structure 500, the protrusions of some docking sections 510 have an arc shape, the protrusions of other docking sections 510 have a square shape, and the protrusions of still other docking sections 510 have a triangular shape, and the protruding directions of the multiple protrusions are the same.

[0120] The bending condition of the bending structure 500 is described in detail below with reference to the accompanying drawings.

[0121] refer to Fig.11 , each docking section 510 has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1; in the extension direction perpendicular to the bending structure 500, the bending structure 500 has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1. The maximum point of the protrusion is the farthest protrusion point of the protrusion, or a point on the farthest protrusion line of the protrusion. The first maximum point of the bending structure 500 is the farthest point among the multiple maximum points of the multiple protrusions, and the first minimum point is the farthest point among the intersections of the recessed part or the protrusion.

[0122] In some embodiments, 0.00005≤T1 / δ1≤500000. T1 / δ1 can be, for example, 0.00005, 0.002, 0.04, 6, 800, 5000, 80000, 500000. T1, δ1, and T1 / δ1 are parameters used to characterize the bending condition of the bending structure 500; when T1 / δ1 increases, the bending becomes smoother, the bending structure 500 has a weaker effect of increasing the contact area of ​​the leakage channel of the side docking surface 400, and a weaker effect of improving the anti-hot spot effect, but the requirement for etching accuracy becomes lower, which is more conducive to processing; when T1 / δ1 decreases, the bending becomes steeper, the bending structure 500 has a stronger effect of increasing the contact area of ​​the leakage channel of the side docking surface 400, and a stronger effect of improving the anti-hot spot effect, but the requirement for etching accuracy becomes higher, which is not very conducive to processing. Therefore, the ratio of T1 to δ1 can be adjusted to achieve a balance between increasing the contact area of ​​the leakage channel and the processing efficiency.

[0123] The value range of T1 may be 0.01-500 micrometers, for example, 0.01 micrometers, 0.1 micrometers, 2 micrometers, 40 micrometers, 200 micrometers, or 500 micrometers.

[0124] The value range of δ1 can be 0.001-200 microns. For example, δ1 is 0.001 microns, 0.01 microns, 0.1 microns, 2 microns, 40 microns, and 200 microns. If δ1 is too small, the effect of improving the anti-hot spot effect will be weakened; if δ1 is too large, it will be unfavorable for processing.

[0125] Combine the following Figure 2 , the overall structure of the back contact battery 100 of an embodiment of the present application is described.

[0126] like Figure 2 As shown, the back contact battery 100 includes: a semiconductor substrate 101, a first doping layer 200 and a second doping layer 300, the main body 204 of the first doping layer and the main body 304 of the second doping layer are alternately and spaced apart on one side of the backlight surface 112 of the semiconductor substrate 101, and the first doping layer 200 and the second doping layer 300 have opposite conductivity types; the extension portion 303 of the second doping layer is staggered and overlapped above the extension portion 203 of the first doping layer in the spacing area 190, thereby forming a conductive connection structure 700, and wherein a single conductive connection structure 700 includes two side docking surfaces 400, and the two side docking surfaces 400 respectively have a bending structure 500.

[0127] Figure 2The back contact battery 100 shown may also include a first dielectric layer 131 located between the first doping layer 200 and the semiconductor substrate 101, a second dielectric layer 132 located between the second doping layer 300 and the semiconductor substrate 101, an insulating layer 150 located between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer, a surface passivation layer 140 located above the first doping layer 200 and the second doping layer 300, a first electrode 121, and a second electrode 122.

[0128] It should be noted that, in terms of the specific electrode structure of the positive electrode and the negative electrode, the back contact battery 100 of the embodiment of the present invention may be a "back contact battery without a main grid". In this case, the electrode structure in the back contact battery only includes a plurality of collector electrodes (a first electrode 121 and a second electrode 122). The collector electrodes may also be referred to as fine grid lines. The plurality of collector electrodes may extend along a first direction and be spaced apart along a second direction. Alternatively, the back contact battery 100 of the embodiment of the present invention may also be a "back contact battery with a main grid. In this case, the back contact battery includes a plurality of collector electrodes and a plurality of bus structures (not shown in the figure). The bus structures may also be referred to as bus electrodes. The bus structures are spaced apart along a first direction and extend along a second direction, and are electrically coupled to collector electrodes of the same conductivity type as themselves. The bus structure may be a structure extending over the entire cell or a structure extending over only a portion of the cell.

[0129] The materials of the various layers and electrodes of the back contact battery 100 of the embodiment of the present invention can refer to any material in the prior art that can be used to prepare the back contact battery 100. The materials of each layer are briefly described below.

[0130] The semiconductor substrate may be a silicon substrate. The silicon substrate may be N-type or P-type silicon with a thickness of 30-500 microns. The backlight surface and the light-facing surface of the semiconductor substrate may be flat. Alternatively, the light-facing surface of the semiconductor substrate may also be a velvet surface.

[0131] The conductivity type of the first doped layer can be N-type, in which case the conductivity type of the second doped layer is P-type; or, the conductivity type of the first doped layer can also be P-type, in which case the conductivity type of the second doped layer is N-type. For the specific materials of the first doped layer and the second doped layer, the N-type doped layer can be one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon and silicon oxide, and its N-type doping element can be one or more of carbon, nitrogen, phosphorus, arsenic, antimony, bismuth, oxygen, sulfur, selenium, and tellurium; the P-type doped semiconductor layer can be one or more of single crystal silicon, polycrystalline silicon, amorphous silicon, microcrystalline silicon, nanocrystalline silicon and silicon oxide, and its P-type doping element can be one or more of boron, aluminum, gallium, indium, thallium, carbon, and nitrogen. The thickness of the first doped layer and the second doped layer can be set as needed, for example, 3-3000nm. Preferably, the doped layer at the top is a P-type doped layer, and the doped layer at the bottom is an N-type doped layer.

[0132] The dielectric layer, the first dielectric layer and the second dielectric layer can be one or more of oxide, nitride, oxynitride, halide, carbide and silicon, and their thickness can be set as needed, for example, 0-10 nm. Preferably, the dielectric layer, the first dielectric layer and the second dielectric layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, etc.

[0133] The insulating layer may be one or more of oxide, nitride, oxynitride, halide, carbide, silicon, and its thickness may be set as required, for example, 0-5000 nm. Preferably, the insulating layer may be one or more of phosphosilicate glass, borosilicate glass, aluminosilicate glass, gallium silicon glass, silicon oxide, aluminum oxide, silicon nitride, silicon oxynitride, silicon carbide, amorphous silicon, etc.

[0134] The surface passivation layer can be one or more of oxide, nitride, oxynitride, halide, carbide, silicon, and its thickness can be set as needed, for example, 0-1000nm. Preferably, the surface passivation layer can be one or more of silicon oxide, aluminum oxide, titanium oxide, niobium oxide, boron oxide, gallium oxide, tin oxide, hafnium oxide, tantalum oxide, indium oxide, tungsten oxide, zinc oxide, silicon nitride, silicon oxynitride, silicon carbide, lithium fluoride, magnesium fluoride, amorphous silicon, microcrystalline silicon, nanocrystalline silicon, etc.

[0135] The method for preparing the back contact battery 100 of the embodiment of the present invention can refer to any method in the prior art that can be used to prepare the back contact battery 100, and is not limited here. The bending structure can be obtained by using existing laser etching or chemical etching methods or other methods. For example, when formed by laser etching, the specific shape of the bending structure can be controlled by controlling the size of the light spot, etc.; for example, when using a chemical etching method, the specific shape of the bending structure can be controlled by adjusting the composition, concentration, and processing time of the chemical reagent.

[0136] Unless there are technical obstacles or contradictions, the various technical features disclosed in this application can be freely combined to form additional embodiments, and these additional embodiments are all within the protection scope of this application.

[0137] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "an example", "some embodiments", or "preferred embodiment" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0138] The embodiments of the present invention are described in detail above. However, aspects of the present invention are not limited to the above embodiments. Various modifications and substitutions may be applied to the above embodiments without departing from the scope of the present invention.

Claims

1. A back contact battery, wherein: The back contact cell comprises: a semiconductor substrate, a first doping layer and a second doping layer; The main body of the first doping layer and the main body of the second doping layer are alternately distributed on the backlight side of the semiconductor substrate, and the first doping layer and the second doping layer have opposite conductivity types; A conductive connection structure is provided between a portion of the first doping layer and a portion of the second doping layer, and a single conductive connection structure includes at least two side abutting surfaces.

2. The back contact cell according to claim 1, wherein: A spacing region is provided between the main body portion of the first doping layer and the main body portion of the second doping layer; The first doping layer further includes an extension of the first doping layer, and the second doping layer further includes an extension of the second doping layer. The extension of the first doping layer and the extension of the second doping layer are electrically connected at the spacing region to form the conductive connection structure.

3. The back contact cell according to claim 2, wherein: The extension portion of the first doping layer and the extension portion of the second doping layer are staggered and overlapped.

4. The back contact cell according to claim 2, wherein: The extension portion of the second doping layer covers the extension portion of the first doping layer to achieve overlapping, and in the extension direction of the spacing region, the length of the extension portion of the second doping layer is greater than the length of the extension portion of the first doping layer.

5. The back contact cell according to claim 4, wherein: The end of the extension portion of the second doping layer extends to the junction of the spacing region and the main portion of the first doping layer.

6. The back contact cell according to claim 5, wherein: The extension portion of the second doping layer extends across the spacing region and extends such that a terminal end of the extension portion of the second doping layer is covered by the main portion of the first doping layer.

7. The back contact cell according to claim 1, wherein: A spacing region is provided between the main body portion of the first doping layer and the main body portion of the second doping layer; The second doped layer further includes an extension of the second doped layer; The extension portion of the second doping layer extends across the spacing region and extends such that a terminal end of the extension portion of the second doping layer is covered by the main portion of the first doping layer.

8. The back contact cell according to claim 1, wherein: The side butt joint surface has a bent structure; The bending structure includes a plurality of connecting sections connected in a bending manner in a direction parallel to the backlight surface.

9. The back contact cell according to claim 8, wherein: Each of the docking sections has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1; In an extension direction perpendicular to the bending structure, the bending structure has a first maximum point and a first minimum point, and the distance between the first maximum point and the first minimum point is δ1; Among them, 0.00005≤T1 / δ1≤500000.

10. A photovoltaic module, wherein: The photovoltaic module comprises: A battery string, the battery string being formed by electrically connecting a plurality of back-contact batteries according to any one of claims 1 to 9; and An encapsulation layer covers the surface of the back contact battery.

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