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 one part of the first doping layer is electrically connected with one part of the second doping layer, a side face butt joint face is formed, and the side face butt joint face is provided with a first bending structure. The invention also provides a photovoltaic module. According to the back contact battery provided by the invention, the contact area of an electric leakage channel of a single hot spot prevention structure can be increased through the side surface butt joint surface with the first bending structure.

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] A portion of the first doping layer and a portion of the second doping layer are electrically connected to form a side butt joint surface, and the side butt joint surface has a first bending structure.

[0007] In the back-contact battery of the present invention, by electrically connecting a portion of the first doped layer and a portion of the second doped layer to form a side docking surface, 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, compared with the docking surface with a planar structure, the side docking surface with a first bend structure can increase the contact area of ​​the leakage channel of a single anti-hot spot structure, effectively reduce the total number of anti-hot spot structures set, and minimize the loss of battery conversion efficiency caused by PN region contact while improving the hot spot effect.

[0008] Optionally, the first bending structure includes a plurality of first abutting sections connected in a bending manner in a direction parallel to the backlight surface.

[0009] Optionally, at least one of the plurality of first docking sections has a second bending structure.

[0010] Optionally, the second bending structure includes a plurality of second abutting sections connected in a bending manner in a direction parallel to the backlight surface.

[0011] Optionally, the first portion of the first doped layer and the second portion of the second doped layer are electrically connected and form a first side abutment surface;

[0012] The second portion of the second doped layer is also electrically connected to the semiconductor substrate and forms a second side interface;

[0013] Wherein, the first side butt joint surface and the second side butt joint surface both have a first bending structure, and the second side butt joint surface further has a second bending structure.

[0014] Optionally, each first docking section has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1;

[0015] Each second docking section has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2;

[0016] Among them, T1>T2.

[0017] Optionally, T1 is 5-100 times greater than T2.

[0018] Optionally, in an extension direction perpendicular to the first bending structure, the first 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;

[0019] In the extension direction perpendicular to the second bending structure, the second bending structure has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2;

[0020] Among them, δ1>δ2.

[0021] Optionally, the value range of T1 is 0.01-500 microns;

[0022] The value range of T2 is 0.001-50 microns;

[0023] The value range of δ1 is 0.001-200 μm;

[0024] The value range of δ2 is 0.0001-20 microns.

[0025] Optionally, each first docking section has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1;

[0026] In the extending direction perpendicular to the first bending structure, the first 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;

[0027] Among them, 0.00005≤T1 / δ1≤500000.

[0028] Optionally, in a direction parallel to the backlight surface, a single side butt joint surface has a bending and unfolding length L and an end straight length D, wherein L>1.001D.

[0029] Optionally, each first docking section has a first protrusion, and the first protrusion has one or more of an arc shape, a square shape, a trapezoidal shape, a triangle shape, and an irregular shape.

[0030] In a second aspect of the present invention, a photovoltaic assembly is provided, wherein the photovoltaic assembly comprises:

[0031] A battery string, wherein the battery string is formed by electrically connecting a plurality of the aforementioned back-contact batteries; and

[0032] The encapsulation layer covers the surface of the battery string.

[0033] 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

[0034] 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:

[0035] Figure 1 It is a partial schematic diagram of some components of a back contact battery according to an embodiment of the present invention, showing the side docking surface.

[0036] Figure 2 Is has Figure 1 A schematic cross-sectional structure diagram of a back contact battery according to an embodiment of the present invention showing the side docking interface.

[0037] Figure 3 yes Figure 2 A partial enlarged schematic diagram of .

[0038] Figure 4 Is has Figure 1 A schematic cross-sectional structure diagram of a back contact battery according to another embodiment of the present invention showing the side docking interface.

[0039] Figure 5 yes Figure 1 A schematic diagram of the side docking surface.

[0040] Figure 6 yes Figure 1 Another schematic diagram of the side docking surface of .

[0041] Figure 7 Is has Figure 1 SEM image of the back contact battery with side docking surface.

[0042] 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.

[0043] 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.

[0044] Fig.10 It is a partial schematic diagram of some components of the back contact battery of an embodiment of the present invention, showing side docking surfaces of different forms.

[0045] Fig.11 Schematic diagrams of first bending structures of different shapes. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] 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 surface 112 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 portion of the first doping layer 200 and a portion of the second doping layer 300 are electrically connected, and a side docking surface 400 is formed, and the side docking surface 400 has a first bending structure 500.

[0052] In the back-contact battery 100 of the embodiment of the present invention, by electrically connecting a portion of the first doping layer 200 and a portion of the second doping layer 300 to form a side docking surface 400, 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 battery 100 to have a lower reverse breakdown voltage when it is shielded, thereby reducing the hot spot risk of the back-contact battery 100, that is, reducing the risk of the back-contact battery 100 being burned due to local heat concentration; at the same time, compared with the docking surface of the planar structure, the side docking surface 400 with the first bending structure 500 can increase the leakage channel contact area of ​​a single side docking surface 400, effectively reducing the total number of anti-hot spot structures, while improving the hot spot effect and minimizing the battery conversion efficiency loss caused by the PN region contact.

[0053] The anti-hot spot structure may also be referred to as an anti-hot spot conductive connection structure, a conductive connection structure, etc. A single battery cell may have one or more conductive connection structures 700, wherein a single conductive connection structure 700 may include one or more side docking surfaces 400. A single "battery cell" may be a full-cell battery cell, a half-cell battery cell, or a battery cell of other specifications.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] exist Figure 8In 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. 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.

[0059] 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 .

[0060] 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.

[0061] 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.

[0062] In this way, a portion of the first doping layer 200 and a portion of the second doping layer 300 are electrically connected to form a side docking interface 400, and the "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 "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.

[0063] 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 can 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, and the spacing region 190 can also be a layer spacing region formed by separating the main body 204 of the first doping layer and the main body 304 of the second doping layer by other layer structures such as an insulating layer.

[0064] The formation position of the side docking surface 400 can be formed at 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 (which can also be called the junction of the spacing region 190 and the strip portion 201 of the first doping layer), and the junction of the spacing region 190 and the second doping region 192 (which can also be called the junction of the spacing region 190 and the strip portion 301 of the second doping layer). Specifically, when the side docking surface 400 is formed in the spacing region 190, all or a part of the extension portion 203 of the first doping layer and all or a part of the extension portion 303 of the second doping layer are electrically connected to form the side docking surface 400; when the side docking surface 400 is formed in the first doping region 191, or at the junction of the spacing region 190 and the first doping region 191, a part of the strip portion 201 of the first doping layer and all or a part of the extension portion 303 of the second doping layer are electrically connected to form the side docking surface 400; when the side docking surface 400 is formed in the second doping region 192, or at the junction of the spacing region 190 and the second doping region 192, a part of the strip portion 301 of the second doping layer and all or a part of the extension portion 203 of the first doping layer are electrically connected to form the side docking surface 400.

[0065] The side butt joint 400 may be formed by butting a portion of the first doping layer 200 and a portion of the second doping layer 300, or by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300. For example, a portion of the first doping layer 200 is overlapped and formed on a portion of the second doping layer 300. For another example, a portion of the second doping layer 300 is overlapped and formed on a portion of the first doping layer 200. Compared with forming the side butt joint by butting and forming the side butt joint by overlapping, the reliability of the electrical connection at the overlapping side butt joint is higher, and a top-to-top butt joint may be formed between the top surface of the doping layer below and the bottom surface of the doping layer above, which is more conducive to improving the anti-hot spot effect. Reference Figure 2 , a portion of the second doping layer 300 overlaps a portion of the first doping layer 200 to form a side interface 400. Figure 4 A portion of the first doping layer 200 and a portion of the second doping layer 300 are butted against each other to form a side butting surface 400 .

[0066] 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. 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 side butt joint surface 400 may be formed by butt jointing between a portion of the first doping layer 200 and a portion of the second doping layer 300, or may be formed by overlapping between a portion of the first doping layer 200 and a portion of the second doping layer 300. In the case where the first doping layer 200 and the second doping layer 300 are both formed on the semiconductor substrate 101, the side butt joint surface 400 may be formed by butt joint between a portion of the first doping layer 200 and a portion of the second doping layer 300, or may be formed by overlapping between a portion of the first doping layer 200 and a portion of the second doping layer 300. 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 portion 204 of the first doping layer 200 is higher than the height of the semiconductor substrate 101 corresponding to the main portion 304 of the second doping layer 300, and the side butt joint surface 400 may be formed by butt joint between all or a portion of the extension portion 303 of the second doping layer and a portion of the first doping layer 200, or may be formed by overlapping between all or a portion of the extension portion 303 of the second doping layer and a portion of the first doping layer 200.

[0067] 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 side butt joint surface 400; 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 side butt joint surface 400, 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 butted against each other.

[0068] For example, Figure 8In the figure, at mark 801, the side butt joint surface 400 is formed by butting between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer at the spacing region 190; at mark 802, the side butt joint surface 400 is formed by overlapping between a part of the strip portion 201 of the first doping layer and the extension portion 303 of the second doping layer at the first doping region 191; at mark 803, the side butt joint surface 400 is formed by overlapping between the extension portion 203 of the first doping layer and a part of the strip portion 301 of the second doping layer at the second doping region 192.

[0069] 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. 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.

[0070] 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.

[0071] 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.

[0072] and Figure 8 similar, Fig. 9 The 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.

[0073] Thus, in the aforementioned case where a portion of the first doped layer 200 and a portion of the second doped layer 300 are electrically connected and form a side butt interface 400, "a portion of the first doped layer" may be a portion of the strip portion 201 of the first doped layer, or may be all or a portion of the connecting portion 202 of the first doped layer, or may be all or a portion of the extending portion 203 of the first doped layer; "a portion of the second doped layer" may be a portion of the strip portion 301 of the second doped layer, or may be all or a portion of the connecting portion 302 of the second doped layer, or may be all or a portion of the extending portion 303 of the second doped layer. It should be understood that a portion of the first doped layer 200 and a portion of the second doped layer 300 in adjacent positions are usually electrically connected and form a side butt interface 400.

[0074] As for the formation position of the side docking surface 400, similar to the foregoing, it can be at the spacing region 190, the first doping region 191, the second doping region 192, the third doping region 193, the fourth doping region 194, the junction of the spacing region 190 and the first doping region 191 (which can also be called the junction of the spacing region 190 and the strip portion 201 of the first doping layer), the junction of the spacing region 190 and the second doping region 192 (which can also be called the junction of the spacing region 190 and the strip portion 301 of the second doping layer), the junction of the spacing region 190 and the third doping region 193 (which can also be called the junction of the spacing region 190 and the extension 203 of the first doping layer), the junction of the spacing region 190 and the fourth doping region 194 (which can also be called the junction of the spacing region 190 and the connecting portion 302 of the second doping layer), etc., which will not be elaborated here.

[0075] As for the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, the specific structure of the spacing region 190, the formation method of the side docking surface 400, and the contact method between a portion of the first doping layer 200 and a portion of the second doping layer 300, they are similar to the above and will not be repeated here.

[0076] For example, Fig. 9 In the figure, at mark 901, the side butt interface 400 may be formed between an extension portion 203 of the first doping layer (the extension portion 203 of the first doping layer is specifically formed by extending from the connecting portion 202 of the first doping layer toward the strip portion 301 of the second doping layer) and a portion of the end of the strip portion 301 of the second doping layer; at mark 902, the side butt interface 400 may be formed between a portion of the strip portion 201 of the first doping layer and an extension portion 303 of the second doping layer (the extension portion 303 of the second doping layer is specifically formed by extending from the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer); at mark 903, the side butt interface 400 may be formed between a portion of the end of the strip portion 201 of the first doping layer and an extension portion 303 of the second doping layer (the extension portion 303 of the second doping layer is specifically formed by extending from the connecting portion 302 of the second doping layer toward the strip portion 201 of the first doping layer).

[0077] In the back contact battery 100 of the embodiment of the present invention, the side interface 400 has a first bending structure 500. In other words, the side interface 400 is not a flat surface. Specifically, in the direction parallel to the backlight surface 112, a single side interface 400 has a bending extension length L (not shown in the figure), an end straight length D (see Figure 1 and Figure 5 ,in Figure 1The distance between point a and point b) is L>1.001D. By limiting the relationship between the bending expansion length L and the end straight line length D to L>1.001D, it can be ensured that the side butt surface 400 forms a bend.

[0078] 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 first bending structure of the one or more local sections is measured, thereby directly obtaining or averaging the size relationship between L and D.

[0079] 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.

[0080] 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.

[0081] 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.

[0082] 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 first bending structure". 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., and also includes substantially, basically, approximately "parallel to", "perpendicular to", etc. In this way, the bending unfolded length L and the end straight line length D are respectively discussing the bending unfolded length and the end straight line length of the second horizontal side. For example, in Figure 1 In the example shown, there is a side interface 400. At this time, the direction parallel to the backlight surface 112, the extending direction of the side interface 400, and the extending direction of the first bending structure 500 are Figure 1 The up and down direction; Fig.10 In the example shown in h), there are three side docking surfaces 400, each of which has a direction parallel to the backlight surface 112, an extension direction of the side docking surface 400, and an extension direction of the first bending structure 500. The directions of the first side docking surface 400 located above and the second side docking surface 400 located below that are parallel to the backlight surface 112, the extension direction of the side docking surface 400, and the extension direction of the first bending structure 500 are specifically Fig.10 h), and the direction of the third side interface 400 located in the middle parallel to the backlight surface 112, the extending direction of the side interface 400, and the extending direction of the first bending structure 500 are specifically Fig.10 h) up and down direction.

[0083] The first 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 first bending structure 500 is described in detail below in conjunction with the accompanying drawings.

[0084] In some embodiments, the first bending structure 500 includes a plurality of first connecting sections 510 connected in a bending manner in a direction parallel to the backlight surface 112. Figure 1 , Figure 5 and Fig.10By configuring the first bending structure 500 to include a plurality of first docking sections 510 connected in a bent manner, it can be ensured that the presence of the first 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.

[0085] In the first bending structure 500, a section having a complete first protrusion alone is referred to as a "first docking section".

[0086] refer to Figure 1 , Figure 5 , Figure 7 , Fig.10 , Fig.11 Each first docking section 510 may have a first protrusion (not numbered in the figure), and the first protrusion may have one or more of an arc shape, a square shape, a trapezoidal shape, a triangular shape, and an irregular shape.

[0087] 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.

[0088] The first protrusions of the plurality of first docking sections 510 in a single first bending structure 500 may have the same shape, and the protruding directions of the first protrusions may be the same. Alternatively, the first protrusions of the plurality of first docking sections 510 in a single first bending structure 500 may have different shapes, and the protruding directions of the first protrusions may be the same. The “protruding direction of the first protrusion” is substantially perpendicular to the extension direction of the first bending structure 500.

[0089] exist Figure 1 In the embodiment, the side docking surface 400 is formed in the spacing area 190, the first protrusions of the first docking sections 510 have arc shapes respectively, and the protruding directions of the first protrusions are the same.

[0090] exist Figure 7 In the embodiment, the side butt joint surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 , and the first protrusions of the first butt joint sections 510 have an arc shape, a trapezoidal shape, or an irregular shape.

[0091] exist Fig.10In a), the side butt joint surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 in a butt joint manner, similar to Figure 1 The multiple first protrusions of the multiple first docking sections 510 respectively have an arc shape, and the protruding directions of the multiple first protrusions are the same.

[0092] exist Fig.10 b), the side butt joint surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 in a butt joint manner, and the first protrusions of the first butt joint sections 510 have square shapes respectively, and the protruding directions of the first protrusions are the same.

[0093] exist Fig.10 c), the side butt joint surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 in a butt joint manner, and the first protrusions of the first butt joint sections 510 have arc shapes respectively, and the protruding directions of the first protrusions are the same.

[0094] exist Fig.10 d), the side butt joint surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 in a butt joint manner, and the first protrusions of the first butt joint sections 510 have a triangular shape, and the protruding directions of the first protrusions are the same.

[0095] exist Fig.10 e), the side butt joint surface 400 is formed in the spacing area 190 in a butt joint manner, similar to Fig.10 d) The first protrusions of the first docking sections 510 have a triangular shape respectively, and the protruding directions of the first protrusions are the same.

[0096] exist Fig.10 f), the side butt surface 400 is formed at the junction of the spacing region 190 and the first doping region 191 in an overlapping manner, similar to Fig.10 d) and Fig.10 e) The first protrusions of the first docking sections 510 have triangular shapes respectively, and the protruding directions of the first protrusions are the same.

[0097] exist Fig.10 g), Fig.10 h), Fig.10 In i), a plurality of side abutment surfaces 400 are formed in the spacing area 190 in an overlapping manner, and a plurality of first protrusions of a plurality of first abutment sections 510 of each side abutment surface 400 respectively have a special-shaped shape.

[0098] In order to more clearly illustrate the first docking section 510 of the first bending structure 500, Fig.11Schematic diagrams of various forms of the first bending structure 500 of the side docking surface 400 are separately shown.

[0099] exist Fig.11 a), similar to Figure 1 and Fig.10 c) In the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have an arc shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 includes an arc-shaped first protrusion and an arc-shaped recessed portion located on both sides of the arc-shaped first protrusion, that is, the first docking section 510 is a section located between the vertices of two adjacent arc-shaped recessed portions.

[0100] exist Fig.11 b), similar to Fig.10 a), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have an arc shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 only includes the arc-shaped first protrusions, that is, the first docking section 510 is a section located between the intersection points of two adjacent arc-shaped first protrusions.

[0101] exist Fig.11 c), similar to Fig.10 b), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have a square shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 includes a square first protrusion and square recessed portions located on both sides of the square first protrusion, that is, the first docking section 510 is a section located between the midpoints of the top edges of two adjacent square recessed portions.

[0102] exist Fig.11 d), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have a trapezoidal shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 only includes the trapezoidal first protrusions, that is, the first docking section 510 is a section located between the intersection points of two adjacent trapezoidal first protrusions.

[0103] exist Fig.11 e), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have a trapezoidal shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 includes a trapezoidal first protrusion and square recessed portions located on both sides of the trapezoidal first protrusion, that is, the first docking section 510 is a section located between the midpoints of the top edges of two adjacent square recessed portions.

[0104] exist Fig.11 f), similar to Fig.10 f), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have a triangular shape, and the protruding directions of the multiple first protrusions are the same, wherein the first docking section 510 only includes triangular first protrusions, that is, the first docking section 510 is a section located between the intersection points of two adjacent triangular first protrusions.

[0105] exist Fig.11 g) and Fig.11 h), in the first bending structure 500, the multiple first protrusions of the multiple first docking sections 510 respectively have irregular shapes, wherein the first docking section 510 includes a section between the vertices or top edge midpoints of two recessed sections located on both sides of a first protrusion.

[0106] exist Fig.11 i), in the first bending structure 500, the first protrusions of some first docking sections 510 have an arc shape, and the first protrusions of other first docking sections 510 have a square shape, and the protruding directions of the plurality of first protrusions are the same.

[0107] exist Fig.11 j), in the first bending structure 500, the first protrusions of some first docking sections 510 have an arc shape, the first protrusions of other first docking sections 510 have a square shape, and the first protrusions of yet other first docking sections 510 have a triangular shape, and the protruding directions of the multiple first protrusions are the same.

[0108] The bending condition of the first bending structure 500 is described in detail below with reference to the accompanying drawings.

[0109] refer to Figure 5 , each first docking section 510 has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; in the extension direction perpendicular to the first bending structure 500, the first 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 first protrusion is the farthest protrusion point of the first protrusion, or a point on the farthest protrusion line of the first protrusion. The first maximum point of the first bending structure 500 is the farthest point among the multiple maximum points of the multiple first protrusions, and the first minimum point is the farthest point among the intersections of the recessed portion or the first protrusion.

[0110] 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 first bending structure 500; when T1 / δ1 increases, the bending becomes smoother, the effect of the first bending structure 500 on increasing the contact area of ​​the leakage channel of the side butt joint 400 becomes weaker, and the effect of improving the anti-hot spot effect becomes weaker, but the requirement for etching accuracy becomes lower, which is more conducive to processing; when T1 / δ1 decreases, the bending becomes steeper, the effect of the first bending structure 500 on increasing the contact area of ​​the leakage channel of the side butt joint 400 becomes stronger, and the effect of improving the anti-hot spot effect becomes stronger, 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.

[0111] 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.

[0112] 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.

[0113] In some embodiments, reference Figure 3 and Figure 6 , at least one of the plurality of first docking sections 510 has a second bending structure 600. Compared with the side docking surface 400 having only the first bending structure 500, the side docking surface 400 having the first bending structure 500 and the second bending structure 600 can increase the contact area of ​​the leakage channel of a single side docking surface 400. At the same time, the presence of the second bending structure 600 also makes the leakage points more evenly dispersed, further effectively preventing local overheating of the back contact battery 100.

[0114] The second bending structure 600 may be any structure that can make the bending of the first docking section of the first bending structure 500 more complicated. In some embodiments, the second bending structure 600 may include a plurality of second docking sections 610 connected in a bending manner in a direction parallel to the backlight surface 112, such as Figure 6 By configuring the second bending structure 600 to include a plurality of second docking sections 610 connected in a bent manner, it can be ensured that the existence of the second bending structure 600 can further increase the contact area of ​​the leakage channel of a single side docking surface 400 and at the same time, further disperse the leakage points evenly.

[0115] The section of the second bending structure 600 that has a complete second protrusion is referred to as a "second docking section". Similar to the first docking section 510, each second docking section 610 may have a second protrusion, and the second protrusion may have one or more of an arc shape, a square shape, a trapezoidal shape, a triangle shape, and a special shape, which will not be described in detail here.

[0116] However, unlike the first bending structure 500, the second bending structure 600 is a bending structure attached to the first docking section 510, and the first docking section 510 itself has a first protrusion. The multiple line segments constituting the first protrusion obviously have different orientations. Therefore, the second bending structure 600 on a single first docking section 510 will have different extension directions. For example, Figure 6 As shown, the first protrusions of the first docking sections 510 of the first bending structure 500 have an arc shape. Figure 6 The first docking section 510 marked with mark 510 has a first line segment (not numbered in the figure) extending outward as a whole and a second line segment (not numbered in the figure) extending inward as a whole, or it can be considered that the first line segment protrudes outward and the second line segment is recessed inward from the protruding end of the first line segment. The first line segment has a first extension direction, the second line segment has a second extension direction, and the first extension direction and the second extension direction are at an angle. In other words, the second bending structure 600 on the first line segment has a first extension direction, and the second bending structure 600 on the second line segment has a second extension direction. When describing the bending of the second bending structure 600 below, the description is based on the second bending structure 600, the second docking section 610, and the second protrusion in the same extension direction. The "protruding direction of the second protrusion" is the extension direction of the line segment roughly perpendicular to the first docking section 510 in which it is located.

[0117] The bending condition of the second bending structure 600 is described in detail below with reference to the accompanying drawings.

[0118] refer to Figure 6 , each second docking section 610 has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2; in the extension direction perpendicular to the second bending structure 600, the second bending structure 600 has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2.

[0119] In an embodiment in which the back contact battery 100 has a first bending structure 500 and a second bending structure 600, T1>T2; and / or, δ1>δ2. As previously mentioned, T1 and δ1 are parameters used to characterize the bending condition of the first bending structure 500. Similarly, T2 and δ2 are parameters used to characterize the bending condition of the second bending structure 600. Usually, T1>T2; and δ1>δ2. By defining T1>T2, δ1>δ2, the first bending structure 500 and the second bending structure 600 can be distinguished from each other, and at the same time, the bending shape of the second bending structure 600 roughly follows the trajectory of the first bending structure 500, so that the setting of the second bending structure 600 does not affect the processing process too much.

[0120] In some embodiments, T1 may be 5-100 times of T2. T1 is, for example, 5, 20, 30, 60, 80, or 100 times of T2. If the difference between T1 and T2 is too small, the further improvement of the anti-hot spot effect will be weakened; if the difference between T1 and T2 is too large, it will be unfavorable for processing.

[0121] The value range of T2 may be 0.001-50 micrometers, for example, 0.001 micrometers, 0.01 micrometers, 0.1 micrometers, 2 micrometers, 30 micrometers, and 50 micrometers.

[0122] The value range of δ2 can be 0.0001-20 microns. For example, δ2 is 0.0001 microns, 0.001 microns, 0.01 microns, 0.2 microns, 4 microns, 10 microns, and 20 microns. If δ2 is too small, the further improvement of the anti-hot spot effect will be weakened; if δ2 is too large, it will be unfavorable for processing.

[0123] In some embodiments, Figure 2 and Figure 3 As shown, the first part of the first doping layer 200 and the second part of the second doping layer 300 are electrically connected to form a first side interface 401; the second part of the second doping layer 300 is also electrically connected to the semiconductor substrate 101, and a second side interface 402 is formed; wherein the first side interface 401 and the second side interface 402 both have a first bending structure 500, and the second side interface 402 also has a second bending structure 600. Considering that the lateral transmission speed of carriers between the first doping layer 200 and the second doping layer 300 is faster, while the lateral transmission speed between the semiconductor substrate 101 and the second part of the second doping layer 300 is slower, by providing the second bending structure 600 on the second side interface 402, the contact area of ​​the leakage channel of a single second side interface 402 can be increased, so that the lateral transmission speed at the second side interface 402 is accelerated. At the same time, the existence of the second bending structure 600 also makes the leakage points more evenly dispersed, further effectively preventing the local overheating of the back contact battery 100.

[0124] In this embodiment, the second bending structure 600 is formed only between the second portion of the second doping layer 300 and the portion of the semiconductor substrate 101 where the height difference is formed, so that no additional processing steps are required. The second bending structure 600 is usually formed on the side of the portion of the semiconductor substrate 101 where the height difference is formed during the alkaline etching process. When no height difference is formed on the semiconductor substrate 101, the second bending structure 600 will not be formed during the alkaline etching process.

[0125] As mentioned above, a single conductive connection structure 700 may include one or more side abutment surfaces 400 .

[0126] In some embodiments, 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 of the aforementioned side interface surfaces 400, such as Fig.10 g), Fig.10 h), Fig.10 i).

[0127] By setting the single conductive connection structure 700 to include at least two side docking surfaces 400, on the one hand, when the size of the 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, by dispersing the electrical connection points to at least two sides, the heat points can be dispersed to avoid local overheating, and the effect of improving the hot spot effect is better. In the overall scheme design, the total number of conductive connection structures 700 can be reduced by this design, while improving the hot spot effect and ensuring that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region. By increasing the number of side docking surfaces, while keeping the total leakage channel contact area of ​​the single conductive connection structure 700 unchanged or slightly increased, the size of the single conductive connection structure 700 can be reduced, 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, by adjusting the size of the single conductive connection structure 700, the total number of conductive connection structures 700, the arrangement method, etc., a balance can be achieved between improving the hot spot effect and ensuring the photoelectric conversion efficiency.

[0128] It is understandable that when a single battery cell has multiple conductive connection structures 700 , all conductive connection structures 700 may include at least two side abutting surfaces 400 , or only some conductive connection structures 700 may include at least two side abutting surfaces 400 .

[0129] Regarding the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, when 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 surface butt joint may also 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 interface surfaces 400 may be formed by overlapping a portion of the first doping layer 200 and a portion of the second doping layer 300 (e.g. 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 whole or part of the extension part 303 of the second doping layer and a part of the main part 204 of the first doping layer, or can be formed by overlapping the whole or part of the extension part 303 of the second doping layer and a part of the main part 204 of the first doping layer at a first position and butting at a second position. There can be one or more of the first position and the second position.

[0130] 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 Fig.10 g)), three side butt joints 400 (see Fig.10 h)), four side butt joints 400, five side butt joints 400 (see Fig.10i)), six side docking surfaces 400, or even up to nine side docking surfaces 400, etc.

[0131] Continue to refer to 10g), Fig.10 h), Fig.10 i), there is a spacing region 190 between the main portion 204 of the first doping layer and the main portion 304 of the second doping layer; the first doping layer 200 also includes an extension portion 203 of the first doping layer, and the second doping layer 300 also includes an extension portion 303 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.

[0132] In some embodiments, Fig.10 g), the extension 203 of the first doping layer and the extension 303 of the second doping layer are electrically connected at the spacing area 190 to form a conductive connection structure 700, and 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. The 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 leakage channel contact area of ​​the single conductive connection structure 700 can be increased without affecting the processing efficiency too much. "Staggered overlap" at the spacing area means that at the spacing area, a part of the end of the extension 203 of the first doping layer and a part 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. Fig.10 g) shows a structure of staggered overlap in the spacing region 190, wherein a single conductive connection structure 700 includes two side butt joints 400; wherein the two side butt joints 400 are both formed between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer.

[0133] In other embodiments, Fig.10 h), 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 perpendicular to the extension portion, 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 may include 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 covered. 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 and covered, 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. Fig.10 h) shows a structure of overlapping in the spacing region 190, wherein a single conductive connection structure 700 includes three side butt joints 400; wherein the three side butt joints 400 are all formed between the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer.

[0134] 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. Fig.10 i) 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, of which the three side docking surfaces 400 in the spacing region are formed by the extension portion 303 of the second doping layer overlapping and covering the extension portion 203 of the first doping layer, and the two side docking surfaces 400 at the junction of the spacing region and the main body 204 of the first doping layer are formed by docking between the end of the extension portion 303 of the second doping layer and the main body 204 of the first doping layer.

[0135] Combine the following Figure 2 and Figure 4 , the overall structure of the back contact battery 100 of an embodiment of the present application is described.

[0136] like Figure 2 and Figure 3 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 surface of the semiconductor substrate 101 corresponding to the main body 304 of the second doping layer is lower than the surface of the semiconductor substrate 101 corresponding to the first doping layer 200, and the extension 303 of the second doping layer overlaps the extension 203 of the first doping layer in the spacing area 190, so as to form a first side interface 401 between the side of the extension 203 of the first doping layer and the extension 303 of the second doping layer, and at the same time, a second side interface 402 is formed between the extension 303 of the second doping layer and the side of the semiconductor substrate 101 corresponding to the extension 203 of the first doping layer, wherein the first side interface 401 has a first bending structure 500, and the second side interface 402 has a first bending structure 500 and a second bending structure 600.

[0137] like Figure 4As 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 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 surface of the semiconductor substrate 101 corresponding to the main body 304 of the second doping layer is lower than the surface of the semiconductor substrate 101 corresponding to the first doping layer 200, and the extension portion 303 of the second doping layer is connected with the extension portion 203 of the first doping layer in the spacing area 190, so as to form a first side connection surface 401 between the side of the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer, and at the same time, a second side connection surface 402 is formed between the extension portion 303 of the second doping layer and the side of the semiconductor substrate 101 corresponding to the extension portion 203 of the first doping layer, wherein the first side connection surface 401 has a first bending structure 500, and the second side connection surface 402 has a first bending structure 500 and a second bending structure 600.

[0138] Figure 2 The back contact cell 100 shown may further include a first dielectric layer 131 between the first doping layer 200 and the semiconductor substrate 101, a second dielectric layer 132 between the second doping layer 300 and the semiconductor substrate 101, an insulating layer 150 between the extension 203 of the first doping layer and the extension 303 of the second doping layer, a surface passivation layer 140 above the first doping layer 200 and the second doping layer 300, a first electrode 121, and a second electrode 122. Similarly, Figure 4 The back contact battery 100 shown may also include a dielectric layer 130 located between the first doping layer 200 , the second doping layer 300 and the semiconductor substrate 101 , 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 .

[0139] 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.

[0140] 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.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] 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.

[0145] 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.

[0146] 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; generally, the first bending structure can be formed by laser etching, and the specific structure of the first bending structure can be controlled by controlling the spot size, etc.; the second bending structure can be formed by chemical etching, and the specific structure of the second bending structure can be controlled by controlling the components of the etching solution, the ratio between the components, the etching time, etc.

[0147] 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.

[0148] 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.

[0149] 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; Part of the first doping layer and part of the second doping layer are electrically connected to form a side butt joint surface, and the side butt joint surface has a first bending structure.

2. The back contact cell according to claim 1, wherein: The first bending structure includes a plurality of first abutting sections connected in a bending manner in a direction parallel to the backlight surface.

3. The back contact cell according to claim 2, wherein: At least one of the plurality of first docking sections has a second bending structure.

4. The back contact cell according to claim 3, wherein: The second bending structure includes a plurality of second abutting sections connected in a bending manner in a direction parallel to the backlight surface.

5. The back contact cell according to claim 3, wherein: The first portion of the first doped layer and the second portion of the second doped layer are electrically connected to form a first side butt joint surface; The second portion of the second doped layer is also electrically connected to the semiconductor substrate and forms a second side interface; Wherein, both the first side abutting surface and the second side abutting surface have the first bending structure, and the second side abutting surface also has the second bending structure.

6. The back contact cell according to claim 4, wherein: Each of the first docking sections has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; Each of the second docking sections has a second protrusion, and the distance between the maximum points of two adjacent second protrusions is T2; Among them, T1>T2.

7. The back contact cell according to claim 6, wherein: T1 is 5-100 times that of T2.

8. The back contact cell according to claim 6, wherein: In an extension direction perpendicular to the first bending structure, the first 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; In the extending direction perpendicular to the second bending structure, the second bending structure has a second maximum point and a second minimum point, and the distance between the second maximum point and the second minimum point is δ2; Among them, δ1>δ2.

9. The back contact cell according to claim 2, wherein: Each of the first docking sections has a first protrusion, and the distance between the maximum points of two adjacent first protrusions is T1; In an extension direction perpendicular to the first bending structure, the first 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. The back contact cell according to claim 2, wherein: In a direction parallel to the backlight surface, a single side butt joint surface has a bending and unfolding length L and an end straight length D, wherein L>1.001D.

11. The back contact cell according to claim 2, wherein: Each of the first docking sections has a first protrusion, and the first protrusion has one or more of an arc shape, a square shape, a trapezoidal shape, a triangle shape, and an irregular shape.

12. 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 11; and A packaging layer covers a surface of the battery string.

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