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; a spacer region is arranged between the main body part of the first doping layer and the main body part of the second doping layer; wherein the first doping layer further comprises an extension part of the first doping layer, the extension part of the first doping layer at least extends across part of the spacer region and extends below the second doping layer, and the extension part of the first doping layer is electrically connected with the second doping layer. The invention also provides a photovoltaic module. According to the back contact battery, the relative position of the second electrode and the laminated structure does not need to be considered, and the alignment problem does not need to be considered.

Description

Technical Field

[0001] The present application 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 application, 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; there is a spacing area between the main body of the first doping layer and the main body of the second doping layer;

[0006] The first doping layer further includes an extension portion of the first doping layer, the extension portion of the first doping layer at least extends across a portion of the spacing region and extends below the second doping layer, and the extension portion of the first doping layer is electrically connected to the second doping layer.

[0007] In the back-contact battery of the present application, by extending the extension portion of the first doping layer at least across a portion of the spacing area and extending below the second doping layer, a side docking surface can be formed at the electrical connection between the first doping layer and the second doping layer. The side docking surface is a built-in diode with a lower reverse breakdown voltage, which is beneficial for the back-contact battery to have a lower reverse breakdown voltage when it is blocked, thereby reducing the risk of hot spots in the back-contact battery. Since the extension portion of the first doping layer extends below the second doping layer, in the subsequent metallization process, the second electrode corresponding to the main body of the second doping layer and the extension portion of the first doping layer will obviously be separated by the second doping layer. Therefore, when printing the second electrode, there is no need to consider the relative position of the second electrode and the stacked structure, and there is no need to consider alignment issues, which makes the processing efficiency higher. At the same time, it does not affect the current collection of the second electrode, and will not cause a short circuit between the second electrode and the second doping layer.

[0008] Optionally, the second doping layer further includes an extension of the second doping layer, the extension of the second doping layer at least extends across a portion of the spacing region, and the extension of the first doping layer and the extension of the second doping layer are electrically connected to form a conductive connection structure. The electrical connection of the extension avoids short circuits caused by the connection of electrical connection points between the electrodes and doping layers of different conductivity types during metallization.

[0009] Optionally, in the extension direction of the spacing region, the length of the extension portion of the first doped layer included in at least one conductive connection structure is equal to the length of the extension portion of the second doped layer; and / or, in the extension direction of the spacing region, the length of the extension portion of the first doped layer included in at least one conductive connection structure is greater than the length of the extension portion of the second doped layer; and / or, in the extension direction of the spacing region, the length of the extension portion of the first doped layer included in at least one conductive connection structure is less than the length of the extension portion of the second doped layer. By extending the extension portion of the first doped layer below the extension portion of the second doped layer and making the two have the same length, short circuits caused by the connection of the electrical connection points of the electrodes and doped layers of different conductivity types during metallization are avoided, but due to the need for accurate alignment, there may be problems with difficult processing. By setting the length of the extension portion of the first doped layer located below to be longer, the electrical connection reliability at the overlap is higher and easier to process. By setting the length of the extension of the second doping layer located above to be longer, a single conductive connection structure can have three side docking surfaces; on the one hand, when the size of a 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 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 the hot spot effect. In the overall scheme design, this design can reduce the total number of conductive connection structures, improve the hot spot effect, and ensure that the photovoltaic module has a high photoelectric conversion efficiency in the forward voltage region. By increasing the number of side docking surfaces, the size of the single conductive connection structure can be reduced while keeping the total leakage channel contact area of ​​the single conductive connection structure unchanged or slightly increased, and the influence of the conductive connection structure on the appearance can be reduced, so that the design space of the back contact battery is larger. Therefore, by adjusting the size of the single conductive connection structure, the total number of conductive connection structures, the arrangement method, etc., a balance can be achieved between improving the hot spot effect and ensuring the photoelectric conversion efficiency.

[0010] Optionally, the first doping layer further includes an extension of the first doping layer, the extension of the first doping layer extends across the spacing region and extends below the main body of the second doping layer, and the extension of the first doping layer is electrically connected to the main body of the second doping layer. In the subsequent metallization process, the second electrode arranged corresponding to the main body of the second doping layer and the extension of the first doping layer (especially the portion of the extension of the first doping layer and the main body of the second doping layer forming a laminated structure) will obviously be separated by the main body of the second doping layer. Therefore, when printing the second electrode, there is no need to consider the relative position of the second electrode and the laminated structure, and there is no need to consider the alignment problem, so that the processing efficiency is higher, and at the same time, it does not affect the current collection of the second electrode, and will not cause a short circuit between the second electrode and the second doping layer.

[0011] Optionally, the extension portion of the first doping layer extends below the main body portion of the adjacent second doping layer, and the end thereof extends below the main body portion of the second doping layer.

[0012] Optionally, a second electrode is disposed above the second doping layer;

[0013] A distance between an end of the extension portion of the first doping layer and an upstream side of a projection of the contact portion of the second electrode in the extension direction of the extension portion of the first doping layer is W1, where W1>0.

[0014] Optionally, a width of the spacing region in an extension direction of the extension portion of the first doping layer is W2, wherein W2>W1.

[0015] Optionally, the extension portion of the first doping layer extends below the main body portion of the adjacent second doping layer, and the end thereof extends beyond a downstream side of the main body portion of the second doping layer.

[0016] Optionally, an extension portion of a first doping layer extends below a main portion of an adjacent second doping layer, and an end extends beyond a downstream side of the main portion of the second doping layer, and the end further extends to an upstream side of a main portion of another first doping layer adjacent to the main portion of the second doping layer.

[0017] Optionally, the main body of the first doping layer includes a strip-shaped portion of the first doping layer, and the main body of the second doping layer includes a strip-shaped portion of the second doping layer;

[0018] In which, the extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the strip portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the strip portion of the second doping layer, and the extension portion of the first doping layer and the strip portion of the second doping layer are electrically connected.

[0019] Optionally, the main body of the first doping layer includes a strip portion of the first doping layer and a connecting portion of the first doping layer, wherein the connecting portion of the first doping layer is used to connect multiple strip portions of the first doping layer; the second doping layer includes a strip portion of the second doping layer and a connecting portion of the second doping layer, wherein the connecting portion of the second doping layer is used to connect multiple strip portions of the second doping layer;

[0020] The back contact battery also includes one or more of the following structures:

[0021] The extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the strip portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the strip portion of the second doping layer, and the extension portion of the first doping layer is electrically connected to the strip portion of the second doping layer;

[0022] The extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the connection portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the connection portion of the second doping layer, and the extension portion of the first doping layer is electrically connected to the connection portion of the second doping layer;

[0023] The extension portion of the first doped layer extends from the entire or partial area of ​​the connecting portion of the first doped layer toward the strip portion of the second doped layer, and the extension portion of the first doped layer extends across the spacing area and extends below the strip portion of the second doped layer, and the extension portion of the first doped layer is electrically connected to the strip portion of the second doped layer.

[0024] Optionally, a stacked structure having at least two side abutting surfaces is formed between the extension portion of the first doping layer and the second doping layer.

[0025] Optionally, the side butt joint surface has a bent structure;

[0026] The bending structure includes a plurality of connecting sections connected in a bending manner in a direction parallel to the backlight surface.

[0027] Optionally, each docking section has a protrusion, and the distance between the maximum points of two adjacent protrusions is T1;

[0028] 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;

[0029] Among them, 0.00005≤T1 / δ1≤500000.

[0030] In a second aspect of the present application, a photovoltaic assembly is provided, comprising:

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

[0032] Encapsulation layer, the encapsulation layer covers the surface of the back contact battery.

[0033] Based on the detailed description of the specific embodiments of the present application in combination with the accompanying drawings below, those skilled in the art will become more aware of the above and other objects, advantages and features of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Features, advantages and exemplary embodiments of the present application will be described below with reference to the accompanying drawings, in which like reference numerals indicate like elements, and in which:

[0035] Figure 1It is a partial schematic diagram of some components of a back-contact battery according to an embodiment of the present application, in which three side docking surfaces are shown with thick solid lines.

[0036] Figure 2 Is has Figure 1 The side butt joint of the back contact battery of one embodiment of the present application is along Figure 1 Schematic diagram of the cross-sectional structure in the X direction.

[0037] Figure 3 yes Figure 2 The back contact of the battery Figure 1 Schematic diagram of the cross-sectional structure in the Y direction.

[0038] Figure 4 It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which three side docking surfaces are shown with thick solid lines.

[0039] Figure 5 yes Figure 4 The back contact of the battery Figure 4 Schematic diagram of the cross-sectional structure in the X direction.

[0040] Figure 6 It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which two side docking surfaces are shown with thick solid lines.

[0041] Figure 7 It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which two side docking surfaces are shown by thick solid lines.

[0042] Figure 8 This is a schematic diagram of the distribution relationship between the first doping layer and the second doping layer of the back contact battery of an embodiment of the present application.

[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 of an embodiment of the present application.

[0044] Fig.10 yes Figure 1 Schematic diagram of a single side docking surface.

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

[0046] Fig.12 It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which a side docking surface is shown by a thick solid line.

[0047] Fig.13It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which a side docking surface is shown by a thick solid line.

[0048] Fig.14 It is a partial schematic diagram of some components of a back-contact battery according to another embodiment of the present application, in which three side docking surfaces are shown with thick solid lines. DETAILED DESCRIPTION

[0049] Hereinafter, embodiments of the present application 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 application. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present application.

[0050] Various structural schematic diagrams according to embodiments of the present application 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 further design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0051] In the context of the present application, 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 application clearer, the present application 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 application and are not used to limit the present application.

[0052] 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. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0053] In the description of this application, 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 this application can be understood according to specific circumstances.

[0054] The present application embodiment 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; there is a spacing area 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer; wherein the first doping layer 200 also includes an extension portion 203 of the first doping layer, the extension portion 203 of the first doping layer at least extends across part of the spacing area 190 and extends below the second doping layer 300, and the extension portion 203 of the first doping layer and the second doping layer 300 are electrically connected.

[0055] In the back contact battery 100 of the embodiment of the present application, by extending the extension portion 203 of the first doping layer at least across a portion of the spacing area 190 and extending below the second doping layer 300, a side butt surface 400 can be formed at the electrical connection between the first doping layer 200 and the second doping layer 300, and the doping layers of opposite conductivity types are locally electrically connected to form a built-in diode with a lower reverse breakdown voltage, which is beneficial for the back contact battery 100 to have a lower reverse breakdown voltage when it is blocked, thereby reducing the risk of hot spots in the back contact battery 100; since the extension portion 203 of the first doping layer extends below the second doping layer 300, in the subsequent metallization process, the second electrode 122 provided corresponding to the main body 304 of the second doping layer and the extension portion 203 of the first doping layer will obviously be separated by the second doping layer 300, so when printing the second electrode 122, there is no need to consider the relative position of the second electrode 122 and the stacked structure 160, and there is no need to consider the alignment problem, so that the processing efficiency is higher, and at the same time, it does not affect the current collection of the second electrode 122, and does not cause a short circuit between the second electrode 122 and the second doping layer 300.

[0056] The stacked structure 160 formed by the extension portion 203 of the first doped layer and the second doped layer 300 is mainly used to prevent hot spots, and can also be called a hot spot prevention structure, a hot spot prevention conductive connection structure, or a conductive connection structure. A single battery cell can have one or more stacked structures 160. A single "battery cell" can be a full-cell battery cell, a half-cell battery cell, or a battery cell of other specifications.

[0057] The embodiment of the present application also provides a photovoltaic module (not shown in the figure), wherein the photovoltaic module includes 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.

[0058] The back contact battery 100 according to the embodiment of the present application will be described in more detail below with reference to the accompanying drawings.

[0059] 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.

[0060] In some embodiments, the second doping layer 300 further includes an extension portion 303 of the second doping layer, the extension portion 203 of the first doping layer at least extends across a portion of the spacing region 190 and extends below the extension portion 303 of the second doping layer, and the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected to form a conductive connection structure 700. The electrical connection of the extension portion avoids short circuits caused by the connection of electrical connection points between electrodes and doping layers of different conductivity types during metallization.

[0061] In other embodiments, the side butt surfaces 400 of different sizes or numbers can be obtained by adjusting the size or coverage relationship of the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer. The size of the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer specifically refers to the length of the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer in the extension direction of the spacing region 190. The "extension direction of the spacing region" refers to the extension direction of the main body portion 204 of the first doping layer and the main body portion 304 of the second doping layer that define the spacing region 190, which will be specifically referred to below. Figure 8 and Fig. 9 Describe in detail.

[0062] like Fig.12As shown, in some embodiments, the extension portion 203 of the first doping layer extends across a portion of the spacing region 190 and extends below the extension portion 303 of the second doping layer, and the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected to form a conductive connection structure 700, wherein in the extension direction of the spacing region 190, the length of the extension portion 303 of the second doping layer is equal to the length of the extension portion 203 of the first doping layer. In this case, a single conductive connection structure 700 includes a side interface 400. The extension portion 203 of the first doping layer extends below the extension portion 303 of the second doping layer and the two have the same length, so that the extension portion 303 of the second doping layer just covers and overlaps the top of the extension portion 203 of the first doping layer. In other words, the entire area of ​​the end of the extension portion 303 of the second doping layer just covers the top of the entire area of ​​the end of the extension portion 203 of the first doping layer, and only a side interface is formed at the side of the end of the extension portion 203 of the first doping layer facing the extension portion 303 of the second doping layer. From the projection on the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer on the semiconductor substrate and the projection of the end of the extension 203 of the first doped layer on the semiconductor substrate completely overlap. Here, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By extending the extension 203 of the first doped layer below the extension 303 of the second doped layer and making the two have the same length, it is avoided that the electrical connection points of the electrodes and the doped layers of different conductivity types are connected during metallization to cause a short circuit, but due to the need for accurate alignment, there may be problems with difficult processing. Therefore, in other embodiments, the length of the extension 303 of the second doped layer is not equal to the length of the extension 203 of the first doped layer.

[0063] like Fig.13As shown, in other embodiments, the extension portion 203 of the first doping layer extends across a portion of the spacing region 190 and extends below the extension portion 303 of the second doping layer, and the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected to form a conductive connection structure 700, wherein in the extension direction of the spacing region 190, the length of the extension portion 303 of the second doping layer is less than the length of the extension portion 203 of the first doping layer. In this case, a single conductive connection structure 700 includes a side butt joint 400. The extension portion 203 of the first doping layer extends below the extension portion 303 of the second doping layer and the length of the extension portion 203 of the first doping layer is longer, so that the extension portion 303 of the second doping layer can only cover a portion of the end of the extension portion 203 of the first doping layer, in other words, the entire area of ​​the end of the extension portion 303 of the second doping layer covers above the local area of ​​the end of the extension portion 203 of the first doping layer, and only a side butt joint is formed at the side of the end of the extension portion 203 of the first doping layer facing the extension portion 303 of the second doping layer. From the projection on the semiconductor substrate, the projection of the end of the extension 303 of the second doped layer on the semiconductor substrate is within the projection of the end of the extension 203 of the first doped layer on the semiconductor substrate. Similarly, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By setting the length of the extension 203 of the first doped layer located below to be longer, the electrical connection reliability at the overlap is higher and it is easier to process.

[0064] like Fig.14As shown, in some other embodiments, the extension portion 203 of the first doping layer extends across part of the spacing region 190 and extends below the extension portion 303 of the second doping layer, and the extension portion 203 of the first doping layer and the extension portion 303 of the second doping layer are electrically connected to form a conductive connection structure 700, wherein 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 side butt surfaces 400. The extension portion 203 of the first doping layer extends below the extension portion 303 of the second doping layer and the length of the extension portion 303 of the second doping layer is longer, so that the extension portion 303 of the second doping layer can cover the entire portion of the end of the extension portion 203 of the first doping layer, in other words, the local area of ​​the end of the extension portion 303 of the second doping layer covers above the entire area of ​​the end of the extension portion 203 of the first doping layer, 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 303 of the second doped layer on the semiconductor substrate completely covers the projection of the end of the extension 203 of the first doped layer on the semiconductor substrate. Similarly, the specific length ratio of the end to the entire extension is not limited and can be adjusted as needed. By setting the length of the extension 303 of the second doped layer located above to be longer, a single conductive connection structure 700 can have three side docking surfaces. By setting a single conductive connection structure 700 to include three 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, while improving the hot spot effect, 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.

[0065] In other embodiments, the extension portion 203 of the first doping layer extends across the spacing region 190 and extends below the main body portion 304 of the second doping layer, and the extension portion 203 of the first doping layer is electrically connected to the main body portion 304 of the second doping layer. In this way, in the subsequent metallization process, the second electrode 122 arranged corresponding to the main body portion 304 of the second doping layer and the extension portion 203 of the first doping layer (especially the portion of the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer forming the stacked structure 160) will obviously be separated by the main body portion 304 of the second doping layer. Therefore, when printing the second electrode 122, there is no need to consider the relative position of the second electrode 122 and the stacked structure 160, and there is no need to consider the alignment problem, so that the processing efficiency is higher, and at the same time, it does not affect the current collection of the second electrode 122, and does not cause a short circuit between the second electrode 122 and the second doping layer 300.

[0066] In the back contact battery 100 of the embodiment of the present application, the extension portion 203 of the first doping layer extends below the main portion 304 of the second doping layer, that is, the main portion 304 of the second doping layer covers the portion of the extension portion 203 of the first doping layer below the main portion 304 of the second doping layer, and a stacked structure 160 having at least two side docking surfaces 400 is formed between the extension portion 203 of the first doping layer and the main portion 304 of the second doping layer. The stacked structure 160 has at least two side docking surfaces 400. On the one hand, when the size of a single stacked structure 160 is certain, the contact area of ​​the leakage channel of the single stacked structure 160 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 be used to reduce the total number of stacked structures 160, while improving the hot spot effect and ensuring that the photovoltaic module has a higher photoelectric conversion efficiency in the forward voltage region; and by increasing the number of side docking surfaces 400, while keeping the total leakage channel contact area of ​​the single stacked structure 160 unchanged or slightly increased, the size of the single stacked structure 160 can be reduced, the impact of the stacked structure 160 on the appearance can be reduced, and the design space of the back contact battery 100 is larger. Therefore, by adjusting the size of the single stacked structure 160, the total number of stacked structures 160, the arrangement method, etc., a balance can be achieved between improving the hot spot effect and ensuring the photoelectric conversion efficiency.

[0067] It can be understood that, herein, "first doping layer" and "second doping layer" are only for convenience of description, and the first doping layer 200 and the second doping layer 300 can be interchanged in terms of function and relative setting position, etc. For example, alternatively, the back contact battery 100 of the embodiment of the present application may include: 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 first doping layer 200 and the second doping layer 300 have opposite conductivity types; 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; wherein the second doping layer 300 also includes an extension portion 303 of the second doping layer, the extension portion 303 of the second doping layer extends across the spacing region 190 and extends below the main body 204 of the first doping layer, and the extension portion 303 of the second doping layer is electrically connected to the main body 204 of the first doping layer.

[0068] 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 shown.

[0069] 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. 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.

[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 a local area of ​​the strip portion 201 of the first doping layer toward the strip portion 301 of the second doping layer, and the extension portion 203 of the first doping layer extends across the spacing region 190 and extends below the strip portion 301 of the second doping layer, so that the extension portion 203 of the first doping layer and the strip portion 301 of the second doping layer are electrically connected to form a stacked structure 160 having at least two side butt surfaces 400, such as Figure 8 As shown by marks 801 and 802.

[0071] Alternatively, the second doping layer 300 may further include an extension portion 303 of the second doping layer, the extension portion 303 of the second doping layer extending from a local area of ​​the main body portion 304 of the second doping layer toward the first doping layer 200, that is, extending from a local area of ​​the strip portion 301 of the second doping layer toward the strip portion 201 of the first doping layer, and the extension portion 303 of the second doping layer extends across the spacing region 190 and extends below the strip portion 201 of the first doping layer, so that the extension portion 303 of the second doping layer and the strip portion 201 of the first doping layer are electrically connected to form a stacked structure 160 having at least two side butt surfaces 400, as shown in FIG. Figure 8 As shown by marks 803 and 804.

[0072] 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.

[0073] Regarding the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, when the extension portion 203 of the first doping layer extends below the main portion 304 of the second doping layer, the first doping layer 200 and the second doping layer 300 may both be formed on the semiconductor substrate 101; or, 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, when the extension portion 303 of the second doping layer extends below the main portion 204 of the first doping layer, the first doping layer 200 and the second doping layer 300 may both be formed on the semiconductor substrate 101; or, 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. Since "first doping layer" and "second doping layer" are only for the convenience of description, the first doping layer 200 and the second doping layer 300 may be interchangeable, so the alternatives are also within the protection scope of the present application.

[0074] 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.

[0075] The aforementioned “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.

[0076] 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. 9In 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.

[0077] 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, and the extension portion 203 of the first doping layer extends across the spacing region 190 and extends below the strip portion 301 of the second doping layer, so that the extension portion 203 of the first doping layer is electrically connected to the strip portion 301 of the second doping layer and forms a stacked structure 160 having at least two side butt surfaces 400, as shown in FIG. Fig. 9 As shown by the marks 902 and 904 in the figure; or, the extension portion 203 of the first doping layer extends from the local area of ​​the strip portion 201 of the first doping layer toward the connecting portion 302 of the second doping layer, and the extension portion 203 of the first doping layer extends across the spacing area 190 and extends below the connecting portion 302 of the second doping layer, so that the extension portion 203 of the first doping layer and the connecting portion 302 of the second doping layer are electrically connected to form a stacked structure 160 having at least two side butt surfaces 400, as shown in FIG. Fig. 9As shown by the marks 903 and 905 in the figure; or, the extension portion 203 of the first doping layer extends from the entire or partial area of ​​the connecting portion 202 of the first doping layer toward the strip portion 301 of the second doping layer (usually the end of the strip portion 301 of the second doping layer adjacent to the connecting portion 202 of the first doping layer), and the extension portion 203 of the first doping layer extends across the spacing region 190 and extends below the strip portion 301 of the second doping layer, so that the extension portion 203 of the first doping layer and the strip portion 301 of the second doping layer are electrically connected to form a stacked structure 160 having at least two side butt surfaces 400, as shown in FIG. Fig. 9 As shown in the mark 901.

[0078] Alternatively, the second doping layer 300 may further include an extension portion 303 of the second doping layer, the extension portion 303 of the second doping layer extending from a local area of ​​the main body portion 304 of the second doping layer toward the first doping layer 200, that is, extending 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. The specific arrangement between the extension portion 303 of the second doping layer and the main body portion 204 of the first doping layer is similar to the above, and will not be repeated here.

[0079] As for the formation method of the extension portion 203 of the first doping layer, the positions of the first doping layer 200 and the second doping layer 300 relative to the semiconductor substrate 101, and the specific structure of the spacing region 190, they are similar to the above and will not be described in detail here.

[0080] The aforementioned “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. Fig. 9In 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.

[0081] As mentioned above, the “first doping layer” and the “second doping layer” can be interchanged. Hereinafter, the structure of the back contact battery 100 of the embodiment of the present application will be described by taking the first doping layer 200 having the extension portion 203 of the first doping layer as an example.

[0082] As described above, the extension portion 203 of the first doped layer extends across the spacing region 190 and extends below the main portion 304 of the second doped layer, so that the extension portion 203 of the first doped layer and the main portion 304 of the second doped layer are electrically connected to form a stacked structure 160 having at least two side interface surfaces 400 .

[0083] Optionally, in the back contact battery 100 of the embodiment of the present application, the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer are electrically connected to form two side butt joint surfaces 400 or three side butt joint surfaces 400 .

[0084] The number of side butt joints 400 formed depends on the position of the end of the extension portion 203 of the first doping layer relative to the main body portion 304 of the second doping layer. Specifically, when the end of the extension portion 203 of the first doping layer does not extend to the downstream side of the main body portion 304 of the second doping layer (i.e., the end of the extension portion extends to the position directly below the main body portion 304 of the second doping layer and ends at a position that does not exceed the main body portion 304 of the second doping layer), the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer can be formed with three side butt joints 400, such as Figure 1 and Figure 4As shown; when the end of the extension portion 203 of the first doping layer extends to the downstream side of the main body portion 304 of the second doping layer, or extends beyond the downstream side of the main body portion 304 of the second doping layer, or extends beyond the downstream side of the main body portion 304 of the second doping layer and further extends to the upstream side of the main body portion 204 of another first doping layer adjacent to the main body portion 304 of the second doping layer, two side butt surfaces 400 are formed, as shown in FIG. Figure 6 and Figure 7 shown.

[0085] Herein, "upstream" and "downstream" are determined based on the first doping layer 200 having the extension portion 203 of the first doping layer, along the extension direction of the extension portion 203 of the first doping layer. For example, if 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, the strip portion 301 of the second doping layer is located downstream; and, for the strip portion 301 of the second doping layer itself, it has two sides in the extension direction of the extension portion 203 of the first doping layer, wherein the side close to the strip portion 201 of the first doping layer is the upstream side of the strip portion 301 of the second doping layer, and the other side away from the strip portion 201 of the first doping layer is the downstream side of the strip portion 301 of the second doping layer. For another example, 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 connection portion 302 of the second doping layer, and the connection portion 302 of the second doping layer is located downstream; and for the connection portion 302 of the second doping layer itself, it has two sides in the extension direction of the extension portion 203 of the first doping layer, wherein the side close to the strip portion 201 of the first doping layer is the upstream side of the connection portion 302 of the second doping layer, and the other side away from the strip portion 201 of the first doping layer is the downstream side of the connection portion 302 of the second doping layer. For another example, the extension portion 203 of the first doping layer extends from the entire or local area of ​​the connection portion 202 of the first doping layer toward the end of the strip portion 301 of the second doping layer adjacent to the connection portion 202 of the first doping layer, and the end of the strip portion 301 of the second doping layer adjacent to the connection portion 202 of the first doping layer is located downstream.

[0086] In some embodiments, the extension portion 203 of the first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end extends below the main body portion 304 of the second doping layer and terminates at a position that does not exceed the main body portion 304 of the second doping layer. In this case, three side abutment surfaces 400 are formed between the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer, such as Figure 1 and Figure 4As shown. By extending the end of the extension portion 203 of the first doping layer to below the main body portion 304 of the second doping layer and terminating at a position that does not exceed the main body portion 304 of the second doping layer, three side butt joint surfaces 400 can be formed, which can increase the total leakage channel contact area, and the single stacked structure 160 can improve the hot spot effect better, thereby reducing the total number of stacked structures 160, while improving the hot spot effect to ensure that the photovoltaic module has a higher photoelectric conversion efficiency in the forward voltage region; and, since the end of the extension portion 203 of the first doping layer only needs to extend to below the main body portion 304 of the second doping layer, the amount of material used is reduced, and the material cost is reduced.

[0087] A second electrode 122 is disposed above the second doping layer 300. The second electrode 122 has a contact portion 1220 that contacts the second doping layer 300. Figure 2 and Figure 5 As shown. Generally, the second electrode 122 may include a transmission portion and a contact portion 1220, and the transmission portion forms an electrical contact with the second doping layer 300 through the contact portion 1220. Similarly, the first electrode 121 may include a transmission portion and a contact portion, and the transmission portion forms an electrical contact with the first doping layer 200 through the contact portion. In the case where the end of the extension portion 203 of the first doping layer extends below the main body portion 304 of the second doping layer, there are two situations that are distinguished by the different relative positions of the end of the extension portion 203 of the first doping layer and the projection of the contact portion 1220 of the second electrode 122. In the first case, the end of the extension portion 203 of the first doping layer does not extend beyond the projection of the contact portion 1220 of the second electrode 122. In other words, the end of the extension portion 203 of the first doping layer does not extend beyond the downstream side of the projection of the contact portion 1220 of the second electrode 122, as shown in FIG. Figure 1 and Figure 2 In the second case, the end of the extension portion 203 of the first doping layer extends beyond the projection of the contact portion 1220 of the second electrode 122. In other words, the end of the extension portion 203 of the first doping layer has a portion of the downstream side that exceeds the projection of the contact portion 1220 of the second electrode 122, as shown in FIG. Figure 4 and Figure 5 As shown. The “projection of the contact portion of the second electrode” is the projection of the contact portion 1220 of the second electrode 122 on the semiconductor substrate 101; and, in the extension direction of the extension portion 203 of the first doping layer, the projection of the contact portion 1220 of the second electrode 122 has an upstream side and a downstream side. The relative position of the end of the extension portion 203 of the first doping layer and the projection of the contact portion 1220 of the second electrode 122 discussed above specifically refers to the relative position of the end of the extension portion 203 of the first doping layer and the downstream side of the projection of the contact portion 1220 of the second electrode 122.

[0088] refer to Figure 1 In some embodiments, the distance between the end of the extension portion 203 of the first doping layer and the upstream side of the projection of the contact portion 1220 of the second electrode 122 in the extension direction of the extension portion 203 of the first doping layer is W1, where W1>0. There is a distance between the end of the extension portion 203 of the first doping layer and the upstream side of the projection of the contact portion 1220 of the second electrode 122, and W1>0, indicating that there is a spacing between the end of the extension portion 203 of the first doping layer and the upstream side of the projection of the contact portion 1220 of the second electrode 122. On the one hand, the collected leakage current can be quickly conducted away through the electrode, shortening the transmission path of the leakage current, which is conducive to further improving the anti-hot spot effect, and on the other hand, it can further reduce the amount of materials used and reduce the material cost. Assuming that the width of the second doping layer 300 in the extension direction of the extension portion 203 of the first doping layer is W3 (not shown in the figure), W1 can be ≤1 / 2W3. Usually, W3∈(30 microns-1000 microns). W3 is, for example, 30 microns, 100 microns, 400 microns, 800 microns, 1000 microns. Optionally, 1000 microns>W1>30 microns. W1 is, for example, 35 microns, 50 microns, 100 microns, 150 microns, 200 microns, 500 microns, 900 microns. By setting W1 to be greater than 30 microns, the reliability of the connection can be ensured, and setting W1 to be less than 1000 microns prevents the leakage area of ​​a single anti-hot spot structure from being too large, thereby affecting the forward power generation efficiency.

[0089] Continue to refer Figure 1 , the width of the spacing region 190 in the extension direction of the extension portion 203 of the first doping layer is W2, wherein W2>W1. By setting W2>W1, the leakage current of the back contact cell 100 in normal working conditions can be made smaller, further ensuring that the photovoltaic module has a higher photoelectric conversion efficiency in the forward voltage region. W2 is as large as possible, usually W2≤1000 microns. Usually, W2∈(35 microns-1000 microns). W2 is, for example, 35 microns, 100 microns, 400 microns, 500 microns, 1000 microns.

[0090] Specifically, Figure 1In the embodiment, the extension portion 203 of the first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end thereof extends below the main body portion 304 of the second doping layer, and the distance W1 between the end of the extension portion 203 of the first doping layer and the upstream side edge of the projection of the contact portion 1220 of the second electrode 122 in the extension direction of the extension portion 203 of the first doping layer is greater than 0. Among them, three side butt joints 400 are formed between the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer, including a first side butt joint 401, a second side butt joint 402, and a third side butt joint 403, wherein the extension directions of the first side butt joint 401 and the second side butt joint 402 are parallel to the extension direction of the extension portion 203 of the first doping layer, and the extension direction of the third side butt joint 403 is perpendicular to the extension direction of the extension portion 203 of the first doping layer. W1 is the distance between the point or line closest to the upstream side of the projection of the contact portion 1220 of the second electrode 122 among the three side abutting surfaces 400 and the upstream side of the projection of the contact portion 1220 of the second electrode 122. Figure 1 , W1 is the distance between the third side abutting surface 403 and the upstream side of the projection of the contact portion 1220 of the second electrode 122 . Figure 2 is along Figure 1 The schematic cross-sectional structure diagram along the X direction shows the third side abutting surfaces 403 , W1 , and W2 , wherein the contact portion 1220 of the second electrode 122 is offset relative to the stacked structure 160 . Figure 3 is along Figure 1 The cross-sectional structure schematic diagram along the Y direction shows the first side butt joint surface 401 and the second side butt joint surface 402.

[0091] 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.

[0092] The width of the main body 204 of the first doping layer in the extension direction of the extension 203 of the first doping layer is W4 (not shown in the figure), and usually, W4∈(30 microns-1000 microns). W4 is, for example, 30 microns, 100 microns, 400 microns, 800 microns, or 1000 microns.

[0093] The effective electrical doping concentration of the extension portion 203 of the first doping layer at the spacing region 190 is generally less than 1E20 cm -3 . Preferably, less than 1E19cm -3. This can effectively reduce the electrical connection current between the main body 204 of the first doping layer and the main body 304 of the second doping layer, thereby reducing reverse leakage and improving the photovoltaic conversion efficiency of the battery. By adjusting the effective electrical doping concentration and the total leakage channel contact area of ​​the side docking surface 400, a balance can be achieved between improving the hot spot effect and ensuring the photovoltaic conversion efficiency. The effective electrical doping concentration of the extension 203 of the first doping layer at the spacing area 190 is, for example, 1E19cm -3 、1E18cm -3 、1E17cm -3 、1E16cm -3 、1E15cm -3 .

[0094] refer to Figure 4 In other embodiments, the end of the extension portion 203 of the first doping layer extends below the main portion 304 of the second doping layer and extends beyond the projection of the contact portion 1220 of the second electrode 122. Figure 1 Compared with the scheme in Figure 4 In the solution, the amount of material used increases and the transmission path of the leakage current increases, but since there is no need to strictly control the relative position between the end of the extension portion 203 of the first doping layer and the contact portion 1220 of the second electrode 122, the processing efficiency is higher.

[0095] Specifically, Figure 4 In the embodiment, the extension portion 203 of the first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end extends below the main body portion 304 of the second doping layer and extends beyond the projection of the contact portion 1220 of the second electrode 122. Three side butt joints 400 are formed between the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer, including a first side butt joint 401, a second side butt joint 402, and a third side butt joint 403, wherein the extension directions of the first side butt joint 401 and the second side butt joint 402 are parallel to the extension direction of the extension portion 203 of the first doping layer, and the extension direction of the third side butt joint 403 is perpendicular to the extension direction of the extension portion 203 of the first doping layer. Figure 5 is along Figure 4 The schematic diagram of the cross-sectional structure along the X direction shows the third side interface 403, wherein the contact portion 1220 of the second electrode 122 is located above the stacked structure 160. In addition, the second electrode 122 may also have multiple contact portions 1220, such as two contact portions 1220, wherein one contact portion 1220 is located above the stacked structure 160, and the other contact portion 1220 is offset relative to the stacked structure 160.

[0096] In other embodiments, the extension portion 203 of the first doped layer extends below the main body portion 304 of the adjacent second doped layer, and the end extends beyond the downstream side of the main body portion 304 of the second doped layer. In this case, two side docking surfaces 400 are formed between the extension portion 203 of the first doped layer and the main body portion 304 of the second doped layer. Compared with the formation of three side docking surfaces 400, although the number of side docking surfaces 400 is reduced, since the length of a single side docking surface 400 in the extension direction of the extension portion 203 of the first doped layer increases, the total leakage channel contact area can still be increased, and a single stacked structure 160 has a better effect in improving the hot spot effect, thereby reducing the total number of stacked structures 160, while improving the hot spot effect and ensuring that the photovoltaic module has a higher photoelectric conversion efficiency in the forward voltage region.

[0097] Taking the first doping layer 200 having the extension portion 203 of the first doping layer (the first doping layer 200 may also be referred to as the upstream first doping layer) as a reference, the main body 304 of the second doping layer may have another main body 204 of the first doping layer downstream of the extension portion 203 of the first doping layer (the first doping layer 200 may also be referred to as the downstream first doping layer), such as Figure 6 and Figure 7 As shown. In the case where the end of the extension portion 203 of the first doping layer extends beyond the downstream side of the main body portion 304 of the second doping layer, there are two situations to distinguish whether the end of the extension portion 203 of the first doping layer reaches the main body portion 204 of another first doping layer. In the first case, the end of the extension portion 203 of the first doping layer does not reach the main body portion 204 of another first doping layer. At this time, the end of the extension portion 203 of the first doping layer is located in the downstream spacing area 190 between the main body portion 304 of the second doping layer and the main body portion 204 of the downstream first doping layer, as shown in FIG. Figure 6 In the second case, the end of the extension portion 203 of the first doping layer reaches the main body portion 204 of another first doping layer. At this time, the end of the extension portion 203 of the first doping layer at least reaches the upstream side of the main body portion 204 of the downstream first doping layer, as shown in FIG. Figure 7 shown.

[0098] refer to Figure 7In some embodiments, the extension portion 203 of a first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end extends beyond the downstream side of the main body portion 304 of the second doping layer, and the end further extends to the upstream side of the main body portion 204 of another first doping layer adjacent to the main body portion 304 of the second doping layer. In this case, the main bodies 204 of the two first doping layers upstream and downstream of the main body portion 304 of the second doping layer are connected through the extension portion 203 of the first doping layer, so that the leakage current collected at the side interface 400 of the stacked structure 160 can be quickly transmitted to both sides and then conducted away through the electrodes on both sides, shortening the transmission path of the leakage current, which is conducive to further improving the anti-hot spot effect.

[0099] Specifically, Figure 7 In the embodiment, the extension portion 203 of the upstream first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end thereof extends beyond the downstream side of the main body portion 304 of the second doping layer, and the end thereof further extends to the upstream side of the main body portion 204 of the downstream first doping layer adjacent to the main body portion 304 of the second doping layer. Two side butt joints 400 are formed between the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer, including a first side butt joint 401 and a second side butt joint 402, wherein the extension directions of the first side butt joint 401 and the second side butt joint 402 are parallel to the extension direction of the extension portion 203 of the first doping layer.

[0100] refer to Figure 6 In other embodiments, the extension portion 203 of the first doping layer extends below the main portion 304 of the adjacent second doping layer, and the end extends beyond the downstream side of the main portion 304 of the second doping layer, but does not reach the main portion 204 of another first doping layer. Figure 7 Compared with the scheme in Figure 6 In the scheme, the transmission speed of the leakage current is reduced, but the material consumption is reduced and the material cost is reduced.

[0101] Specifically, Figure 6 In the embodiment, the extension portion 203 of the first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the end extends beyond the downstream side of the main body portion 304 of the second doping layer, but does not reach the main body portion 204 of another first doping layer. Two side butt joints 400 are formed between the extension portion 203 of the first doping layer and the main body portion 304 of the second doping layer, including a first side butt joint surface 401 and a second side butt joint surface 402, wherein the extension direction of the first side butt joint surface 401 and the second side butt joint surface 402 is parallel to the extension direction of the extension portion 203 of the first doping layer.

[0102] Reference below Figure 8 and Fig. 9 , several examples of the back contact battery 100 according to the embodiment of the present application are described.

[0103] exist Figure 8 In the embodiment, at mark 801, the extension portion 203 of the first doping layer extends below the main body portion 304 of the adjacent second doping layer, and the terminal end extends to below the main body portion 304 of the second doping layer; at mark 802, the extension portion 203 of the first doping layer and the terminal end extend beyond the downstream side of the main body portion 304 of the second doping layer, and the terminal end further extends to the upstream side of the main body portion 204 of another first doping layer adjacent to the main body portion 304 of the second doping layer; at mark 803, the extension portion 303 of the second doping layer extends below the main body portion 204 of the adjacent first doping layer, and the terminal end extends to below the main body portion 204 of the first doping layer; at mark 804, the extension portion 303 of the second doping layer and the terminal end extend beyond the downstream side of the main body portion 204 of the first doping layer, and the terminal end further extends to the upstream side of the main body portion 304 of another second doping layer adjacent to the main body portion 204 of the first doping layer.

[0104] exist Fig. 9In the embodiment, at mark 901, the extension portion 203 of the first doped layer (the extension portion is formed by extending from the connecting portion 202 of the first doped layer toward the end of the strip portion 301 of the adjacent second doped layer) extends below the end of the strip portion 301 of the adjacent second doped layer, and the end thereof extends below the strip portion 301 of the second doped layer; at mark 902, the extension portion 203 of the first doped layer (the extension portion is formed by extending from the strip portion 201 of the first doped layer toward the strip portion 301 of the adjacent second doped layer) extends below the strip portion 301 of the adjacent second doped layer, and the end thereof extends below the strip portion 301 of the second doped layer; at mark 903, the extension portion 203 of the first doped layer (the extension portion is formed by extending from the end of the strip portion 201 of the first doped layer toward the connecting portion 302 of the adjacent second doped layer) extends below the strip portion 301 of the adjacent second doped layer. The doped layer extends below the connecting portion 302, and the end thereof extends below the connecting portion 302 of the second doped layer; at mark 904, the extension portion 203 of the first doped layer (the extension portion is formed by extending from the strip portion 201 of the upstream first doped layer toward the strip portion 301 of the adjacent second doped layer) extends below the strip portion 301 of the adjacent second doped layer, and the end thereof extends to the strip portion 201 of the downstream first doped layer downstream of the strip portion 301 of the second doped layer; at mark 904, the extension portion 203 of the first doped layer (the extension portion is formed by extending from the end portion of the strip portion 201 of the upstream first doped layer toward the connecting portion 302 of the adjacent second doped layer) extends below the connecting portion 302 of the adjacent second doped layer, and the end thereof extends to the end portion of the strip portion 201 of the downstream first doped layer downstream of the connecting portion 302 of the second doped layer.

[0105] In some embodiments, in the back contact battery 100 of the embodiment of the present application, the side docking surface 400 has a bent structure 500, in other words, the side docking surface 400 is not a flat surface. When there are multiple side docking surfaces, one or more of them may have a bent structure 500. In the back contact battery 100 of the embodiment of the present application, compared with the docking surface with a planar structure, the side docking surface 400 with a bent structure 500 can increase the leakage channel contact area of ​​a single side docking surface 400, effectively reduce the total number of anti-hot spot structures, and minimize the battery conversion efficiency loss caused by the PN region contact while improving the hot spot effect.

[0106] 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.10 ), 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.

[0107] 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 400 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 400, and the end straight line length D of the one or more local sections is 10 microns. The bending unfolding 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.

[0108] 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.

[0109] 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.

[0110] 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.

[0111] 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 1 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. The directions of the first side butt joint surface 401 and the second side butt joint surface 402 parallel to the backlight surface 112, the extension directions of the side butt joint surfaces, and the extension directions of the bending structure 500 are specifically Figure 1 The left and right directions of the third side docking surface 403, the direction parallel to the backlight surface 112, the extending direction of the side docking surface, and the extending direction of the bending structure 500 are specifically Figure 1 Up and down direction.

[0112] 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.

[0113] 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.10 and Fig.11 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.

[0114] In the bending structure 500, a section having a complete protrusion alone is referred to as a "joint section".

[0115] refer to Fig.10 and Fig.11 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.

[0116] 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.

[0117] 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.

[0118] exist Fig.11 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.

[0119] exist Fig.11 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.

[0120] exist Fig.11 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.

[0121] exist Fig.11 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.

[0122] exist Fig.11e), 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.

[0123] exist Fig.11 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.

[0124] exist Fig.11 g) and Fig.11 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.

[0125] exist Fig.11 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.

[0126] exist Fig.11 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.

[0127] The bending condition of the bending structure 500 is described in detail below with reference to the accompanying drawings.

[0128] refer to Fig.10 , 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] Combine the following Figure 2 , the overall structure of the back contact battery 100 of an embodiment of the present application is described.

[0133] 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 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; there is a spacing area 190 between the main body 204 of the first doping layer and the main body 304 of the second doping layer; wherein the first doping layer 200 also includes an extension portion 203 of the first doping layer, the extension portion 203 of the first doping layer extends across the spacing area 190 and extends below the main body 304 of the second doping layer, and the extension portion 203 of the first doping layer and the main body 304 of the second doping layer are electrically connected.

[0134] 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.

[0135] 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 application may be a "back contact battery without a main grid". In this case, the electrode structure in the back contact battery 100 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 the first direction and be spaced apart along the second direction. Alternatively, the back contact battery 100 of the embodiment of the present application may also be a "back contact battery with a main grid. In this case, the back contact battery 100 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 the first direction and extend along the second direction, and are electrically coupled to collector electrodes of the same conductivity type as themselves. The bus structure may be a structure that extends over the entire cell, or a structure that extends over only part of the cell.

[0136] The materials of the various layers and electrodes of the back contact battery in the embodiment of the present application can refer to any material that can be used to prepare the back contact battery in the prior art. The materials of each layer are briefly described below.

[0137] 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.

[0138] 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.

[0139] 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 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.

[0140] 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.

[0141] 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.

[0142] The method for preparing the back contact battery of the embodiment of the present application can refer to any method in the prior art that can be used to prepare the back contact battery, 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, it can be formed by laser etching, and the specific structure of the bending structure can be controlled by controlling the spot size, etc.

[0143] 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.

[0144] 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 application. 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.

[0145] The embodiments of the present application are described in detail above. However, aspects of the present application 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 application.

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; there is a spacing area between the main body of the first doping layer and the main body of the second doping layer; The first doping layer further includes an extension portion of the first doping layer, the extension portion of the first doping layer at least extends across a portion of the spacing region and extends below the second doping layer, and the extension portion of the first doping layer is electrically connected to the second doping layer.

2. The back contact cell according to claim 1, wherein: The second doping layer further includes an extension portion of the second doping layer, the extension portion of the second doping layer at least extends across a portion of the spacing region, and the extension portion of the first doping layer and the extension portion of the second doping layer are electrically connected to form a conductive connection structure.

3. The back contact cell according to claim 2, wherein: In the extension direction of the spacing region, the length of the extension portion of the first doping layer included in at least one of the conductive connection structures is equal to the length of the extension portion of the second doping layer; and / or, in the extension direction of the spacing region, the length of the extension portion of the first doping layer included in at least one of the conductive connection structures is greater than the length of the extension portion of the second doping layer; and / or, in the extension direction of the spacing region, the length of the extension portion of the first doping layer included in at least one of the conductive connection structures is less than the length of the extension portion of the second doping layer.

4. The back contact cell according to claim 1, wherein: The extension portion of the first doping layer extends across the spacing region and extends below the main portion of the second doping layer, and the extension portion of the first doping layer is electrically connected to the main portion of the second doping layer.

5. The back contact cell according to claim 4, wherein: The extension portion of the first doping layer extends below the main portion of the adjacent second doping layer, and the end thereof extends below the main portion of the second doping layer and terminates at a position that does not exceed the main portion of the second doping layer.

6. The back contact cell according to claim 5, wherein: A second electrode is disposed above the second doped layer; A distance between an end of the extension portion of the first doping layer and an upstream side of a projection of the contact portion of the second electrode in an extension direction of the extension portion of the first doping layer is W1, where W1>0.

7. The back contact cell according to claim 5, wherein: The width of the spacing region in the extension direction of the extension portion of the first doping layer is W2, wherein W2>W1.

8. The back contact cell according to claim 1, wherein: The extension portion of the first doping layer extends below the main body portion of the adjacent second doping layer, and the end thereof extends beyond the downstream side of the main body portion of the second doping layer.

9. The back contact cell according to claim 4, wherein: An extension portion of one of the first doping layers extends below the main portion of the adjacent second doping layer, and the end extends beyond the downstream side of the main portion of the second doping layer, and the end further extends to the upstream side of the main portion of another first doping layer adjacent to the main portion of the second doping layer.

10. The back contact cell according to claim 1, wherein: The main body of the first doping layer includes a strip-shaped portion of the first doping layer, and the main body of the second doping layer includes a strip-shaped portion of the second doping layer; The extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the strip portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the strip portion of the second doping layer, and the extension portion of the first doping layer and the strip portion of the second doping layer are electrically connected.

11. The back contact cell according to claim 1, wherein: The main body of the first doping layer includes a strip portion of the first doping layer and a connecting portion of the first doping layer, wherein the connecting portion of the first doping layer is used to connect multiple strip portions of the first doping layer; the second doping layer includes a strip portion of the second doping layer and a connecting portion of the second doping layer, wherein the connecting portion of the second doping layer is used to connect multiple strip portions of the second doping layer; Wherein, the back contact battery further includes one or more of the following structures: The extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the strip portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the strip portion of the second doping layer, and the extension portion of the first doping layer is electrically connected to the strip portion of the second doping layer; The extension portion of the first doping layer extends from a local area of ​​the strip portion of the first doping layer toward the connection portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the connection portion of the second doping layer, and the extension portion of the first doping layer is electrically connected to the connection portion of the second doping layer; The extension portion of the first doping layer extends from the entire or partial area of ​​the connecting portion of the first doping layer toward the strip portion of the second doping layer, and the extension portion of the first doping layer extends across the spacing area and extends below the strip portion of the second doping layer, and the extension portion of the first doping layer and the strip portion of the second doping layer are electrically connected.

12. The back contact cell according to claim 1, wherein: A stacked structure having at least two side butting surfaces is formed between the extension portion of the first doping layer and the second doping layer.

13. The back contact cell according to claim 12, 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.

14. The back contact cell according to claim 13, 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.

15. 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 14; and A packaging layer covers a surface of the battery string.

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