Photovoltaic cell, module, and system

Abstract

The present disclosure provides a photovoltaic cell, a module, and a system. A first opening is formed in a first part of a back passivation film layer that is located on a first doping layer. A first conductive barrier portion is provided at the first opening. A first print paste layer is provided on the first part. The first print paste layer is electrically connected to the first conductive barrier portion. The thickness of the first print paste layer is greater than the thickness of the first conductive barrier portion.

Description

Photovoltaic cells, modules and systems

[0001] Cross-reference of related applications

[0002] This disclosure claims priority to Chinese patent application No. 202510005698.4, filed on January 2, 2025, with the China National Intellectual Property Administration, entitled “Back Contact Battery, Battery Module and Photovoltaic System”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to the field of solar cell technology, and more particularly to a back-contact cell, cell string, cell module and photovoltaic system. Background Technology

[0004] A back-contact solar cell is a type of cell in which both the emitter and base contact electrodes are placed on the back of the cell. The light-receiving surface of this cell is not obstructed by any metal electrodes, thereby effectively improving the cell's efficiency.

[0005] In related technologies, back-contact solar cells have P-type and N-type doped layers on their back side, with P-type electrodes on the P-type doped layer and N-type electrodes on the N-type doped layer. However, the electrical performance and efficiency of existing back-contact solar cells still need improvement.

[0006] Public content

[0007] This disclosure provides a back-contact battery, a battery module, and a photovoltaic system.

[0008] This disclosure is implemented as follows: the back contact battery of this disclosure includes: a silicon wafer having a front side and a back side; a first doped layer and a second doped layer, the first doped layer and the second doped layer being disposed at a distance along a first direction on the back side and both extending along a second direction, the second direction intersecting the first direction, and the first doped layer and the second doped layer having opposite doping types; a back passivation film layer, the back passivation film layer being at least stacked on the first doped layer and the second doped layer, the back passivation film layer including a first portion stacked on the first doped layer, at least the first portion having a first opening formed thereon; at least one first conductive barrier structure, the first conductive barrier structure including a first conductive barrier portion, the first conductive barrier portion being at least partially disposed within the first opening and in contact with the first doped layer; a first printing paste layer, the first printing paste layer being disposed on the first portion and electrically connected to the first conductive barrier portion, the thickness of the first printing paste layer being greater than the thickness of the first conductive barrier portion.

[0009] In some embodiments, the ratio between the thickness of the first printed paste layer and the thickness of the first conductive barrier is greater than 1 and less than or equal to 5000.

[0010] In some embodiments, the ratio between the thickness of the first printed paste layer and the thickness of the first conductive barrier is greater than 1 and less than or equal to 500.

[0011] In some embodiments, the back contact battery further includes a first antioxidant protective layer, which is stacked on the first printing paste layer.

[0012] In some embodiments, the first antioxidant protective layer includes at least one of a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

[0013] In some embodiments, the back contact battery further includes a first welding layer, which is stacked on the first printed paste layer and is used for welding with a solder strip.

[0014] In some embodiments, the first solder layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, and an alloy layer containing tin and nickel.

[0015] In some embodiments, the back contact battery further includes a first metal plating layer stacked on the first printed paste layer.

[0016] In some embodiments, the first metal plating layer includes at least one of electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer.

[0017] In some embodiments, the back contact battery further includes a second antioxidant protective layer or a second welding layer stacked on the first metal plating layer.

[0018] In some embodiments, the second antioxidant protective layer includes at least one of a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

[0019] In some embodiments, the second solder layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, and an alloy layer containing tin and nickel.

[0020] In some embodiments, the first conductive barrier includes at least one of a silver layer, an aluminum layer, a nickel layer, a titanium layer, an aluminum metal alloy layer, an aluminum-silicon alloy layer, an aluminum paste layer, a silver paste layer, a titanium alloy layer, a graphite layer, and a transparent conductive film layer.

[0021] In some embodiments, the first printing paste layer includes at least one of copper paste printing layer, aluminum paste printing layer, copper-aluminum paste printing layer, silver-plated copper paste printing layer, nickel-plated copper paste printing layer, and tin-plated copper paste printing layer.

[0022] In some embodiments, the first portion has a plurality of first openings, which are spaced apart along a second direction. The number of first conductive blocking portions corresponds one-to-one with the number of first openings. The first printing paste layer is electrically connected to all the first conductive blocking portions.

[0023] In some embodiments, the back contact battery satisfies one of the following: each first conductive barrier is independent of the others; the first conductive barrier structure further includes a plurality of first conductive connections, the first conductive connections connecting two adjacent first conductive barriers, the first conductive connections being disposed on the first portion and not in contact with the first doped layer.

[0024] In some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is 5 μm-5000 μm, and the spacing between two adjacent first openings in the second direction is 10 μm-2000 μm.

[0025] In some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is 10 μm-500 μm, and the spacing between two adjacent first openings in the second direction is 10 μm-500 μm.

[0026] In some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is 10 μm-50 μm, and the spacing between two adjacent first openings in the second direction is 30 μm-300 μm.

[0027] In some embodiments, in a single first conductive barrier structure, the ratio between the sum of the contact areas of all first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is greater than or equal to 0.0001 and less than 1.

[0028] In some embodiments, in a single first conductive barrier structure, the ratio between the sum of the contact areas of all first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is 0.0001-0.1.

[0029] In some embodiments, in a single first conductive barrier structure, the ratio between the sum of the contact areas of all first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is 0.0005-0.02.

[0030] In some embodiments, the back contact battery satisfies at least one of the following: the thickness of the first printed paste layer is 5um-50um; the thickness of the first conductive barrier portion is greater than or equal to 10nm and less than 5um.

[0031] In some embodiments, the back passivation film layer further includes a second portion stacked on the second doped layer, at least one second portion having a second opening formed thereon; the back contact cell further includes: at least one second conductive barrier structure, the second conductive barrier structure including a plurality of second conductive barrier portions, the second conductive barrier portions being at least partially disposed within the second opening and in contact with the second doped layer; and a second printing paste layer, the second printing paste layer being disposed on the second portion and electrically connected to all the second conductive barrier portions.

[0032] In some embodiments, the thickness of the second printed paste layer is greater than the thickness of the second conductive barrier portion.

[0033] In some embodiments, the ratio between the thickness of the second printed paste layer and the thickness of the second conductive barrier is greater than 1 and less than 5000.

[0034] In some embodiments, the ratio between the thickness of the second printed paste layer and the thickness of the second conductive barrier is greater than 1 and less than 500.

[0035] In some embodiments, the back contact battery further includes a third antioxidant protective layer, which is stacked on the second printing paste layer.

[0036] In some embodiments, the back contact battery further includes a third welding layer, which is stacked on the second printed paste layer and is used for welding with the solder strip.

[0037] In some embodiments, the back contact battery further includes a second metal plating layer stacked on the second printed paste layer.

[0038] In some embodiments, the second metal plating layer includes at least one of electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer.

[0039] In some embodiments, the back contact battery further includes a fourth antioxidant protective layer or a fourth welding layer stacked on the second metal plating layer.

[0040] In some embodiments, the second portion has a plurality of second openings, which are spaced apart along a second direction. The number of second conductive blocking portions corresponds one-to-one with the number of second openings, and the second printing paste layer is electrically connected to all the second conductive blocking portions.

[0041] In some embodiments, the back contact battery satisfies one of the following: each of the second conductive blocking portions is independent of each other; the second conductive blocking structure further includes a plurality of second conductive connecting portions, the second conductive connecting portions connecting two adjacent second conductive blocking portions, and the second conductive blocking portions being disposed on the second portion and not in contact with the second doped layer.

[0042] In some embodiments, in the second conductive barrier structure, the length of the portion of the second conductive barrier located within the second opening and in contact with the second doped layer in the second direction is 5 μm-5000 μm, and the spacing between two adjacent second openings in the second direction is 10 μm-2000 μm.

[0043] In some embodiments, in the second conductive barrier structure, the portion of the second conductive barrier located within the second opening and in contact with the second doped layer has a length of 10 μm-500 μm in the second direction, and the spacing between two adjacent second openings in the second direction is 10 μm-500 μm.

[0044] In some embodiments, in the second conductive barrier structure, the portion of the second conductive barrier located within the second opening and in contact with the second doped layer has a length of 10 μm-50 μm in the second direction, and the spacing between two adjacent second openings in the second direction is 30 μm-300 μm.

[0045] In some embodiments, in a single second conductive barrier structure, the ratio between the sum of the contact areas of all second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is greater than or equal to 0.0001 and less than 1.

[0046] In some embodiments, in a single second conductive barrier structure, the ratio between the sum of the contact areas of all second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is 0.0001-0.1.

[0047] In some embodiments, in a single second conductive barrier structure, the ratio between the sum of the contact areas of all second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is 0.0005-0.02.

[0048] In some embodiments, the back contact battery satisfies at least one of the following: the thickness of the second printed paste layer is 5μm-50μm;

[0049] The thickness of the second conductive barrier is greater than or equal to 10 nm and less than 5 μm.

[0050] This disclosure also provides a battery assembly including a plurality of the aforementioned back contact batteries.

[0051] This disclosure also provides a photovoltaic system, which includes the aforementioned battery module.

[0052] In the back-contact battery, battery module, and photovoltaic system of this disclosure, a first opening is formed on a first portion of the back passivation film layer located on the first doped layer. A first conductive barrier is provided at the first opening, and a first printed paste layer is provided on the first portion. The first printed paste layer is electrically connected to the first conductive barrier to achieve current output. Thus, through the provision of the first conductive barrier and the first printed paste layer, the blocking function of the first conductive barrier can reduce the probability of deep-level elements in the first printed paste layer entering the first doped layer and the silicon wafer, or even completely block deep-level elements, reducing defects introduced by deep-level elements and thus ensuring the electrical performance of the back-contact battery. Simultaneously, the provision of the first printed paste layer can achieve current convergence output. Setting the thickness of the first printed paste layer to be greater than the thickness of the first conductive barrier can improve the lateral conductivity of the back-contact battery, reduce transmission losses, and further improve the electrical performance and efficiency of the back-contact battery.

[0053] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0054] Figure 1 is a schematic diagram of the modules of the photovoltaic system provided in the embodiments of this disclosure.

[0055] Figure 2 is a schematic diagram of the battery assembly provided in an embodiment of this disclosure.

[0056] Figure 3 is a schematic diagram of the planar structure of the back contact battery provided in an embodiment of this disclosure;

[0057] Figure 4 is a schematic cross-sectional view of the back contact battery along line IV-IV in Figure 3.

[0058] Figure 5 is another cross-sectional structural diagram of the back contact battery along line IV-IV in Figure 3.

[0059] Figure 6 is another cross-sectional view of the back contact battery along line IV-IV in Figure 3.

[0060] Figure 7 is another cross-sectional view of the back contact battery along line IV-IV in Figure 3.

[0061] Figure 8 is a schematic cross-sectional view of the back contact battery along line VIII-VIII in Figure 3.

[0062] Figure 9 is another cross-sectional structural diagram of the back contact battery along line VIII-VIII in Figure 3;

[0063] Figure 10 is another cross-sectional view of the back contact battery along line VIII-VIII in Figure 3.

[0064] Figure 11 is another cross-sectional view of the back contact battery along line VIII-VIII in Figure 3.

[0065] Figure 12 is a schematic planar structure diagram of a back contact battery provided with a solder strip according to an embodiment of this disclosure;

[0066] Figure 13 is another planar structural diagram of the back contact battery provided in the embodiment of this disclosure when a solder strip is provided.

[0067] Key component symbols: Photovoltaic system 1000, battery module 200, back contact cell 100, silicon wafer 10, front side 11, back side 12, first doped layer 20, second doped layer 30, back passivation film layer 40, first part 41, first opening 411, second part 42, second opening 421, first conductive barrier part 51, first conductive connection part 52, first printing paste layer 60, first welding layer 70, first anti-oxidation protective layer 72, first metal plating layer 80, second anti-oxidation protective layer 90, second welding layer 92, second conductive barrier part 111, second conductive connection part 112, second printing paste layer 120, third welding layer 130, third anti-oxidation protective layer 132, second metal plating layer 140, fourth anti-oxidation protective layer 150, fourth welding layer 152. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this disclosure, and should not be construed as limiting this disclosure. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining this disclosure and are not intended to limit this disclosure.

[0069] In the description of this disclosure, it should be understood that the terms "upper", "lower", "left", "right", "lateral", "longitudinal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this disclosure and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this disclosure.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this disclosure, "several" means two or more, unless otherwise explicitly specified.

[0071] In this disclosure, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0072] The following disclosure provides numerous different embodiments or examples for implementing various structures of this disclosure. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this disclosure. Furthermore, at least one of the reference numerals and letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and arrangements discussed. In addition, various specific examples of processes and materials are provided in this disclosure, but those skilled in the art will recognize at least one other application of processes and use cases for other materials.

[0073] Please refer to Figures 1 and 2. The photovoltaic system 1000 in this embodiment may include the battery module 200 in this embodiment, and the battery module 200 in this embodiment may include a plurality of back contact batteries 100 in this embodiment.

[0074] In embodiments of this disclosure, multiple back-contact batteries 100 in the battery assembly 200 can be connected in series to form multiple battery strings. The current output of each battery string can be achieved through one of the following methods: series connection, parallel connection, or a combination of series and parallel connections. For example, as shown in Figures 12 and 13, the connection between individual battery cells can be achieved by welding solder strips 210, or the connection between individual battery strings can be achieved by busbars. In some embodiments, the individual battery strings can form a battery cell array, and then be encapsulated together by a front panel, a front adhesive film, a rear adhesive film, and a back panel to form the battery assembly 200.

[0075] Please refer to Figures 3 and 4. The back contact battery 100 in this embodiment may include a silicon wafer 10, a first doped layer 20, a second doped layer 30, a back passivation film layer 40, a first conductive barrier structure, and a first printed paste layer 60.

[0076] The silicon wafer 10 has a front side 11 and a back side 12. A first doped layer 20 and a second doped layer 30 are disposed at intervals along a first direction on the back side 12 and both extend along a second direction, which intersects the first direction. The first doped layer 20 and the second doped layer 30 have opposite doping types, one of which is a P-type doped layer and the other is an N-type doped layer. In some embodiments, the back contact cell 100 has a plurality of first doped layers 20 and a plurality of second doped layers 30, which may be arranged alternately along the first direction. As shown in FIG3, in some embodiments, the first direction and the second direction may be the longitudinal direction and the transverse direction of the back contact cell 100, respectively, and they are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, such as the two diagonal directions of the cell, which are not limited here.

[0077] It should be noted that, in some embodiments of this disclosure, the first doped layer 20 and the second doped layer 30 may both be directly located within the silicon wafer 10. For example, they can be directly diffused onto the silicon wafer 10 to form the first doped layer 20 and the second doped layer 30 directly within the silicon wafer 10. In other embodiments, the first doped layer 20 and the second doped layer 30 may both be disposed on the silicon wafer 10. For example, they can both be formed on the silicon wafer 10 by deposition. Of course, in some embodiments, one of the first doped layer 20 and the second doped layer 30 may be located within the silicon wafer 10, while the other may be located on the silicon wafer 10; no specific limitation is made here.

[0078] A back passivation film layer 40 is at least stacked on the first doped layer 20 and the second doped layer 30. In some embodiments, the back passivation film layer 40 may completely cover the back side 12 of the entire silicon wafer 10. As shown in FIG4, the back passivation film layer 40 may include a first portion 41 (i.e., the portion of the back passivation film layer 40 corresponding to the first doped layer 20) stacked on the first doped layer 20, and a first opening 411 is formed on the first portion 41.

[0079] As shown in Figure 4, the number of first conductive barrier structures is at least one. The first conductive barrier structure includes a first conductive barrier portion 51, which is at least partially disposed within the first opening 411 and in contact with the first doped layer 20.

[0080] A first printed paste layer 60 is disposed on a first portion 41 of the back passivation film layer 40 and is electrically connected to a first conductive barrier portion 51. The thickness of the first printed paste layer 60 is greater than the thickness of the first conductive barrier portion 51. In this document, the “thickness” of each structure refers to the length of the structure in the thickness direction of the back contact battery 100.

[0081] It should be noted that, in the embodiments disclosed herein, the function of the first conductive blocking portion 51 is to effectively block deep-level elements in the fabrication of the first printed paste layer 60 while forming a conductive ohmic contact with the first doped layer 20, thereby reducing the probability of deep-level elements in the first printed paste layer 60 entering the doped layer or even the silicon wafer 10.

[0082] In the back contact battery 100, battery module 200, and photovoltaic system 1000 of the embodiments of this disclosure, a first opening 411 is formed on the first portion 41 of the back passivation film layer 40 located on the first doped layer 20. A first conductive barrier portion 51 is provided at the first opening 411, and a first printed paste layer 60 is provided on the first portion 41. The first printed paste layer 60 is electrically connected to the first conductive barrier portion 51 to realize current output. In this way, through the provision of the first conductive barrier portion 51 and the first printed paste layer 60, the blocking function of the first conductive barrier portion 51 can reduce the probability of deep-level elements in the first printed paste layer 60 entering the first doped layer 20 and the silicon wafer 10, or even completely block deep-level elements, reduce the defects introduced by deep-level elements, and thus ensure the electrical performance of the back contact battery 100. Meanwhile, the first printed paste layer 60 enables current convergence and output. Setting the thickness of the first printed paste layer 60 to be greater than the thickness of the first conductive barrier portion 51 improves the lateral conductivity of the back contact battery 100, reduces transmission losses, and further enhances the electrical performance and efficiency of the back contact battery 100. In other words, in the technical solution of this disclosure, while improving lateral conductivity to reduce transmission losses, it effectively blocks deep-level elements in the first printed paste layer 60 from entering the first doped layer 20 and the silicon wafer 10, thereby further improving the performance of the back contact battery 100 and increasing its efficiency.

[0083] Specifically, in this embodiment, the silicon wafer 10 can be a monocrystalline silicon wafer or a polycrystalline silicon wafer, and it can be a P-type silicon wafer or an N-type silicon wafer, without any specific limitation. The back passivation film layer 40 can be at least one of an aluminum oxide film layer, a silicon nitride film layer, a silicon oxynitride film layer, and a silicon oxide film layer, and it can be a single-layer film structure or a multilayer film structure with two or more layers, without any specific limitation.

[0084] Furthermore, in this disclosure, it is preferable that all the first portions 41 of the first doped layer 20 have a first opening 411, and the first conductive blocking portion 51 is located at the first opening 411. Of course, in some embodiments, the first opening 411 may be formed on only some of the first portions 41 of the first doped layer 20, and this is not limited here. In this disclosure, the first conductive blocking structure may be provided on all the first portions 41, or it may be provided on only some of the first portions 41, and this is not limited here.

[0085] It should be noted that, in the embodiments disclosed herein, the first printing paste layer 60 refers to a paste layer formed by screen printing using paste, and not a film layer formed by PVD coating or other methods in the field of solar energy technology.

[0086] In some embodiments, the ratio between the thickness of the first printed paste layer 60 and the thickness of the first conductive barrier portion 51 is greater than 1 and less than or equal to 5000. Thus, by setting the thickness ratio within this reasonable range, costs can be controlled while ensuring the blocking performance of the first conductive barrier portion 51 and improving its lateral conductivity.

[0087] Specifically, in such embodiments, the thickness ratio between the two can be, for example, one of the following: 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000.

[0088] Furthermore, in such an embodiment, the ratio between the thickness of the first printed paste layer 60 and the thickness of the first conductive barrier portion 51 is preferably greater than 1 and less than or equal to 500. Thus, by setting the thickness ratio within this preferred range, both barrier performance and lateral conductivity can be guaranteed while minimizing costs.

[0089] Specifically, in such embodiments, the thickness ratio between the two can be, for example, one of the following values: 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, or any other value greater than 1 and less than 500, without any specific limitation herein.

[0090] In some embodiments, the thickness of the first printed paste layer 60 can be 5μm-50μm. Setting the thickness of the first printed paste layer 60 within this reasonable range avoids the situation where its thickness is too low, resulting in the desired improvement in lateral conductivity, and also avoids the situation where its thickness is too high, leading to excessive costs. In other words, this setting can improve lateral conductivity and reduce transmission losses while controlling costs.

[0091] Specifically, in such an embodiment, the thickness of the first printing paste layer 60 can be any value between 5 μm and 50 μm. For example, the thickness of the first printing paste layer 60 can be one of 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 25 μm, 35 μm, 40 μm, 45 μm, and 50 μm.

[0092] In such an embodiment, the thickness of the first conductive barrier portion 51 follows the ratio rule mentioned above, and preferably the thickness ratio of the first printed paste layer 60 to the first conductive barrier portion 51 is greater than 1 and less than or equal to 500.

[0093] In some embodiments, the thickness of the first conductive blocking portion 51 can be greater than or equal to 10 nm and less than 5 μm. This avoids the situation where the thickness of the first conductive blocking portion 51 is too small, resulting in insufficient blocking of deep-level elements and poor blocking effect, while also preventing excessive thickness from leading to excessive cost. In other words, this design ensures effective blocking while avoiding excessive cost.

[0094] Specifically, in such an embodiment, the thickness of the first conductive barrier portion 51 can be any value between greater than 10 nm and less than 5 μm. The thickness of the first conductive barrier portion 51 can be, for example, one of the following: 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, or 4.9 μm.

[0095] In some embodiments, the first printing paste layer 60 may include at least one of a copper paste printing layer, an aluminum paste printing layer, a copper-aluminum paste printing layer, a silver-plated copper paste printing layer, a nickel-plated copper paste printing layer, and a tin-plated copper paste printing layer. Thus, using such a printing paste layer for the first printing paste layer 60 can reduce costs while ensuring the conductivity of the first printing paste layer 60.

[0096] Specifically, in such embodiments, the first printing paste layer 60 can be made of low-temperature paste. For example, the copper paste printing layer can be made of low-temperature copper paste, the aluminum paste printing layer can be made of low-temperature aluminum paste, and the copper-aluminum paste printing layer can be made of low-temperature copper-aluminum paste. During the manufacturing process, the low-temperature paste can be printed by means of screen printing or the like, and then cured by means of drying or the like. The first printing paste layer 60 only forms conductive contact with the first conductive barrier portion 51, and will not burn through the first portion 41 of the back passivation film layer 40 to contact the first doped layer 20.

[0097] In some embodiments, the first conductive blocking portion 51 may be at least one of a silver layer, an aluminum layer, a nickel layer, a titanium layer, an aluminum alloy layer, an aluminum-silicon alloy layer, an aluminum paste layer, a silver paste layer, a titanium alloy layer, a graphite layer, and a transparent conductive film layer. Thus, the first conductive blocking portion 51 can not only effectively block deep-level elements in the first printed paste layer 60, but also give it superior conductivity, improving carrier collection efficiency. At the same time, it is less likely to cause a significant reduction in the minority carrier lifetime in the bulk region.

[0098] Specifically, in some embodiments, the first conductive barrier portion 51 may be made of a burn-through paste, such as a burn-through silver paste, a burn-through aluminum paste, etc. In such cases, the first opening 411 may be formed by directly burning through a portion of the first portion 41 during the formation of the first conductive barrier portion 51.

[0099] Of course, in some embodiments, the first conductive barrier portion 51 can also be fabricated by PVD or other methods. For example, in some embodiments, the first conductive barrier portion 51 can be a PVD silver layer, PVD aluminum layer, or other film layer. For example, in some embodiments, a plurality of first openings 411 can be formed on the first portion 41 firstly, and then a silver layer or an aluminum layer can be deposited on the first openings 411 by PVD to form a plurality of isolated first conductive barrier portions 51. Then, the isolated first conductive barrier portions 51 are electrically connected together by printing a first printing paste layer 60.

[0100] Referring to Figure 5, in some embodiments, the back contact battery 100 may further include a first welding layer 70, which is disposed on the first printed paste layer 60 and is used for welding to the solder ribbon 210. Thus, by providing an additional welding layer on the first printed paste layer 60, the stability during the welding process of the solder ribbon 210 can be improved, avoiding poor weld formation and thus poor welding stability resulting from direct welding of the first printed paste layer 60.

[0101] Specifically, in such an embodiment, the first solder layer 70 may include at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, and an alloy layer containing tin and nickel. This allows for improved soldering performance with the solder ribbon 210 while simultaneously forming excellent conductive contact with the first printed paste layer 60.

[0102] Referring to Figure 5, in some embodiments, the back contact battery 100 may further include a first antioxidant protective layer 72, which is stacked on the first printed paste layer 60. The antioxidant capacity of the first antioxidant protective layer 72 is greater than that of the first printed paste layer 60. That is, the first welding layer 70 in Figure 5 is replaced by the first antioxidant protective layer 72. In this way, by setting the first antioxidant protective layer 72, the first printed paste layer 60 can be protected against oxidation, effectively preventing the first printed paste layer 60 from being exposed to air for a long time during the transportation and storage of the back contact battery 100, which would generate oxides and lead to a deterioration in welding performance and conductivity.

[0103] In some embodiments, the first antioxidant protective layer 72 may be a layer structure with excellent antioxidant properties. For example, it may include at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer. The first antioxidant protective layer 72 may be formed on the first printing paste layer 60 by means of PVD deposition, inkjet printing, or the like.

[0104] In some embodiments, the first antioxidant protective layer 72 can also be used for welding with the solder ribbon, which can be welded together with the first printing paste layer 60 to the solder ribbon.

[0105] Referring to Figure 6, in some other embodiments, the back contact battery 100 may further include a first metal plating layer 80 stacked on the first printed paste layer 60. Thus, by providing the first metal plating layer 80 on the first printed paste layer 60, conductivity can be enhanced, transmission loss reduced, and the first printed paste layer 60 can be protected, improving its reliability and weather resistance.

[0106] In such an embodiment, the first metal plating layer 80 may include at least one of the following: electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer. Thus, by using electroplating or electroless plating to form the aforementioned type of metal plating layer, cost can be controlled while ensuring weldability and conductivity.

[0107] Please refer to Figure 6. In some embodiments, the back contact battery 100 may further include a second antioxidant protective layer 90 stacked on the first metal plating layer. The antioxidant capacity of the second antioxidant protective layer 90 is greater than that of the first metal plating layer 80. Thus, by providing the first metal plating layer 80, its welding performance when welded to the solder ribbon 210 can be guaranteed, while the second antioxidant protective layer 90 can protect the first metal plating layer 80, effectively preventing the first metal plating layer 80 from being exposed to air for a long time during transportation and storage, thus avoiding the formation of oxides and resulting in poor welding performance and conductivity. At the same time, it can also effectively prevent the phenomenon of organic matter, dust and other impurities adhering to the surface, which would lead to poor appearance and affect efficiency.

[0108] In some embodiments, the first metal plating layer 80 is preferably an electroplated copper layer. Electroplated copper layers have better solderability, lower cost, and better conductivity, which can improve the collection efficiency of charge carriers.

[0109] Specifically, it can be understood that the first metal plating layer 80 serves both as a welding layer and as a carrier collection layer through the first printed paste layer 60 and the first conductive barrier portion 51. It requires a relatively active metal for fabrication, such as the electroplated copper layer mentioned above. However, highly active metal plating layers are prone to oxidation, leading to poor subsequent welding performance. Therefore, this disclosure effectively avoids this situation by providing a second anti-oxidation protective layer 90 on the first metal seed layer.

[0110] Specifically, in such embodiments, the first metal plating layer 80 may be a highly active metal electroplating layer, such as an electroplated copper layer, and the second anti-oxidation protective layer 90 may be an inert metal layer. For example, in some embodiments, the second anti-oxidation protective layer 90 may include at least one of a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, and a metal oxide layer, which may be formed on the first metal plating layer 80 by means of PVD deposition, inkjet printing, etc.

[0111] Of course, in other embodiments, the second antioxidant protective layer 90 may also include an organic or inorganic film layer capable of resisting oxidation, such as an inorganic film layer with a chain structure. Specific details are not limited here, but an inert metal layer is preferred. That is, in this disclosure, the second antioxidant protective layer 90 may include at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

[0112] In some embodiments, the second antioxidant protective layer 90 may also be a magnetic layer. Thus, during the welding process with the solder ribbon 210, the second antioxidant protective layer 90 can adsorb the solder ribbon 210, effectively preventing the solder ribbon 210 from shifting during welding, improving the stability and reliability of the welding process. In other words, the second antioxidant protective layer 90 can effectively prevent oxidation of the first metal plating layer 80 while also positioning and pre-fixing the solder ribbon 210 during welding.

[0113] Specifically, in such embodiments, the magnetic layer refers to a film layer that has magnetic adsorption function itself or a film layer that has magnetic adsorption function after being energized. The magnetic layer can be made entirely of magnetic materials.

[0114] Of course, it is understood that in some embodiments, the second antioxidant protective layer 90 may not be a magnetic layer made entirely of magnetic materials, but may contain magnetic material components. For example, magnetic materials may be added to inert metal layers such as tin layer, nickel layer and metal oxide layer mentioned above, so that the antioxidant protective layer can generate magnetic attraction to solder ribbon 210.

[0115] In addition, some metal particles may be spattered during the welding process. The magnetic attraction can be used to attract some of these metal particles, thereby reducing surface contamination of the solar cells, improving the light absorption capacity of the solar cells, and increasing the light conversion efficiency of the solar cells.

[0116] Referring to Figure 6, in some embodiments, instead of a second antioxidant protective layer 90, a second welding layer 92 may be provided on the first metal plating layer 80. In this case, the second welding layer 92 is stacked on the first metal plating layer 80 and is used for welding with the solder strip 210. That is, the second antioxidant protective layer 90 in Figure 6 is replaced by the second welding layer 92. Thus, the provision of the second welding layer 92 can ensure the welding performance with the solder strip, while also protecting the first metal plating layer 80.

[0117] In such an embodiment, the second solder layer 92 may include at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, or an alloy layer containing tin and nickel. This allows for excellent electrical conductivity while ensuring solderability.

[0118] In some embodiments, only one continuous first opening 411 may be formed on the first portion 41. In such cases, the first conductive blocking structure includes only one first conductive blocking portion 51, which is disposed at the first opening 411.

[0119] Referring to Figures 4-7, in some embodiments, the first portion 41 may have multiple first openings 411, which are spaced apart along the second direction. The number of first conductive blocking portions 51 corresponds one-to-one with the number of first openings 411, and the first printed paste layer 60 is electrically connected to all the first conductive blocking portions 51. Thus, by forming a plurality of spaced first openings 411 only in a portion of the first portion 41 and by providing first conductive blocking portions 51 only within the first openings 411, the proportion of the metallized area on the first doped layer 20 can be reduced, reducing recombination caused by metallization and improving the efficiency of the back contact battery 100.

[0120] Specifically, in the embodiments disclosed herein, the first conductive blocking portion 51 may be located only within the first opening 411 (as shown in Figures 4-7), or it may be partially located within the first opening 411, with the other part extending above the first portion 41 at the edge of the first opening 411. No specific limitation is made here.

[0121] Referring to Figures 4-7, in some embodiments, when the first portion 41 has a plurality of spaced first openings 411, each first conductive barrier portion 51 is independent of each other (i.e., does not directly contact each other). In this way, the amount of material used in the first conductive barrier structure can be reduced, thereby lowering the cost.

[0122] Specifically, in such a case, the first conductive blocking portion 51 may be located only within the first opening 411. Of course, in some embodiments, the first conductive blocking portion 51 may also partially protrude from the first opening 411 and extend to the first portion 41 of the edge of the first opening 411. In such a case, the first printing paste layer 60 surrounds the portion of the first conductive blocking portion 51 that protrudes from the first opening 411.

[0123] Referring to Figure 7, in some embodiments, the first conductive barrier structure may further include a plurality of first conductive connection portions 52. Each first conductive connection portion 52 connects two adjacent first conductive barrier portions 51. The first conductive connection portions 52 are disposed on the first portion 41 and do not contact the first doped layer 20. Thus, by providing the first conductive connection portions 52, the plurality of first conductive barrier portions 51 can be connected into a whole, increasing the contact area between the first conductive barrier structure and the first printed paste layer 60, thereby improving conductivity.

[0124] In some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction is 5 μm-5000 μm, and the spacing between two adjacent first openings 411 in the second direction is 10 μm-2000 μm. This avoids the situation where the length of a single first conductive barrier 51 is too large, resulting in an excessively large metallization area and excessive recombination, thus affecting efficiency. It also avoids the situation where the length of a single first conductive barrier 51 is too small, resulting in an insufficient contact area with the first printed paste layer 60, which could easily lead to unstable contact between the two layers.

[0125] Meanwhile, setting the spacing between two adjacent first openings 411 within the aforementioned reasonable range can prevent the metallized area from being too large, and also prevent excessive carrier transport distance and transmission loss during collection caused by excessively large spacing between two adjacent first openings 411. In other words, this setting can control the metallized area within a reasonable range, avoiding excessive metallization recombination loss and excessive carrier transport loss, thereby balancing the relationship between recombination and transport loss caused by metallization, achieving a better matching effect, and thus improving the electrical performance of the back contact battery 100.

[0126] Specifically, in such an embodiment, the length of the portion of the first conductive barrier portion 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction can be any value between 5μm and 5000μm, for example, one of 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 1000μm, 1500μm, 2000μm, 2500μm, 3000μm, 4000μm, and 5000μm.

[0127] The spacing between two adjacent first openings 411 in the second direction can be any value between 10μm and 2000μm, such as one of 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 1000μm, 1500μm, and 2000μm.

[0128] Furthermore, in some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction is preferably 10μm-1000μm, and the spacing between two adjacent first openings 411 in the second direction is 10μm-1000μm.

[0129] This allows for a better match between the recombination and transport losses caused by metallization, further improving the electrical performance of the back contact battery 100.

[0130] Furthermore, in some embodiments, in the first conductive barrier structure, the length of the portion of the first conductive barrier portion 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction is preferably 10μm-500μm, and the spacing between two adjacent first openings 411 in the second direction is 10μm-500μm.

[0131] Specifically, in such an embodiment, in the first conductive barrier structure, the length of the portion of the first conductive barrier 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction is preferably 10 μm-100 μm, and the spacing between two adjacent first openings 411 in the second direction is 30 μm-500 μm. Most preferably, it is 10 μm-50 μm and 30 μm-300 μm.

[0132] That is to say, in this disclosure, in the first conductive barrier structure, the length of the portion of the first conductive barrier portion 51 located in the first opening 411 and in contact with the first doped layer 20 in the second direction is preferably 10μm-50μm, and the distance between two adjacent first openings 411 in the second direction is 30μm-300μm.

[0133] Specifically, through repeated research and demonstration by the inventors of this disclosure, by setting the above two values ​​within this optimal range, the recombination and transmission losses caused by metallization can achieve the best matching effect, and the performance of the back contact battery 100 can reach its optimal level.

[0134] Specifically, in such an embodiment, the length of the portion of the first conductive blocking portion 51 located within the first opening 411 and in contact with the first doped layer 20 in the second direction can be any value between 10 μm and 50 μm, for example, one of 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm. The spacing between two adjacent first openings 411 in the second direction can be any value between 30 μm and 300 μm, for example, one of 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, and 300 μm.

[0135] In some embodiments, in a single first conductive barrier structure, the ratio between the sum of the contact areas of all first conductive barrier portions 51 and the first doped layer 20 and the area of ​​the first doped layer 20 is greater than or equal to 0.0001 and less than 1. It should be noted that this area ratio refers to the ratio of the sum of the contact areas of all first conductive barrier portions 51 and the first doped layer 20 on a single first doped layer 20 to the area of ​​that single first doped layer 20. This avoids situations where the metallization area on the first doped layer 20 is too small, leading to excessive carrier transport losses, and also avoids situations where the metallization area is too large, leading to high metallization recombination and affecting efficiency. This balances the relationship between metallization recombination and carrier transport losses, optimizing the performance of the back contact battery 100.

[0136] Furthermore, in such an embodiment, the area ratio between the two is preferably 0.0001-0.5. This further optimizes the relationship between balancing metallization recombination and carrier transport losses, achieving a better matching effect.

[0137] In such embodiments, the ratio between the two is preferably 0.0001-0.1, more preferably 0.0005-0.05, and most preferably 0.0005-0.02. That is to say, in the embodiments of this disclosure, in a single first conductive barrier structure, the ratio between the sum of the contact areas of all the first conductive barrier portions 51 and the first doped layer 20 and the area of ​​the first doped layer 20 is most preferably greater than or equal to 0.0005 and less than or equal to 0.02.

[0138] Specifically, through repeated research and demonstration in this disclosure, by setting the ratio of the two above in the optimal range of 0.0005-0.02, the recombination and transmission losses caused by metallization can be optimally matched, and the performance and efficiency of the back contact battery 100 can be optimized.

[0139] Referring to Figure 8, in some embodiments, the back passivation film layer 40 further includes a second portion 42 (i.e., the portion of the back passivation film layer 40 corresponding to the second doped layer 30) stacked on the second doped layer 30, and a second opening 421 is formed on the second portion 42. The back contact battery 100 also includes a second conductive barrier structure and a second printed paste layer 120. The second conductive barrier structure includes a second conductive barrier portion 111, which is at least partially disposed within the second opening 421 and in contact with the second doped layer 30. The second printed paste layer 120 is disposed on the second portion 42 and is electrically connected to the second conductive barrier portion 111. Thus, the second opening 421 is formed on the second portion 42 of the back passivation film layer 40 located on the second doped layer 30, the second conductive barrier portion 111 is disposed at the second opening 421, and the second printed paste layer 120 is disposed on the second portion 42. The second printed paste layer 120 is electrically connected to the second conductive barrier portion 111 to achieve current output. Thus, by providing the second conductive barrier 111 and the second printed paste layer 120, the blocking function of the second conductive barrier 111 can reduce the probability of deep-level elements in the second printed paste layer 120 entering the second doped layer 30 and the silicon wafer 10, or even completely block the deep-level elements, reduce the defects introduced by the deep-level elements, and thus ensure the electrical performance of the back contact battery 100.

[0140] In this disclosure, it is preferable that all second portions 42 of the second doped layer 30 have second openings 421, and the second conductive blocking portion 111 is located at the second opening 421. Of course, in some embodiments, only some of the second portions 42 of the second doped layer 30 may have second openings 421, and this is not limited here. In this disclosure, all second portions 42 may have second conductive blocking structures, or only some of the second portions 42 may have second conductive blocking structures, and this is not limited here.

[0141] It should be noted that, in the embodiments disclosed herein, the second printing paste layer 120 refers to a paste layer formed by screen printing using paste, and not a film layer formed by PVD coating or other methods in the field of solar energy technology.

[0142] In some embodiments, the thickness of the second printed paste layer 120 is greater than the thickness of the second conductive barrier portion 111. Thus, the second printed paste layer 120 enables current convergence output, and setting the thickness of the second printed paste layer 120 to be greater than the thickness of the second conductive barrier portion 111 improves the lateral conductivity of the back contact battery 100, reduces transmission losses, and further enhances the electrical performance and efficiency of the back contact battery 100. That is, in this embodiment, while improving lateral conductivity to reduce transmission losses, it effectively blocks deep-level elements in the second printed paste layer 120 from entering the second doped layer 30 and the silicon wafer 10, thereby further improving the performance of the back contact battery 100 and increasing its efficiency.

[0143] In some embodiments, the ratio between the thickness of the second printed paste layer 120 and the thickness of the second conductive barrier portion 111 is greater than 1 and less than or equal to 5000. Thus, by setting the thickness ratio within this reasonable range, cost can be controlled while ensuring the blocking performance of the second conductive barrier portion 111 and improving its lateral conductivity. Specifically, in such embodiments, the thickness ratio can be, for example, one of the following: 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500, 5000.

[0144] Furthermore, in such an embodiment, the ratio between the thickness of the second printed paste layer 120 and the thickness of the second conductive barrier portion 111 is preferably greater than 1 and less than or equal to 500. Thus, by setting the thickness ratio within this preferred range, both barrier performance and lateral conductivity can be guaranteed while minimizing costs.

[0145] Specifically, in such embodiments, the thickness ratio between the two can be, for example, one of the following values: 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, or any other value greater than 1 and less than 500, without any specific limitation herein.

[0146] In some embodiments, the thickness of the second printing paste layer 120 is 5μm-50μm. Setting the thickness of the second printing paste layer 120 within this reasonable range avoids the situation where its thickness is too low, resulting in the desired improvement in lateral conductivity, or it is too thick, leading to excessive cost. In other words, this configuration can improve lateral conductivity and reduce transmission loss while controlling costs.

[0147] Specifically, in such an embodiment, the thickness of the second printing paste layer 120 can be any value between 5μm and 50μm, for example, one of 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 15μm, 20μm, 25μm, 35μm, 40μm, 45μm, and 50μm.

[0148] In such an embodiment, the thickness of the second conductive barrier portion 111 follows the ratio rule described above, and preferably the thickness ratio of the second printing paste layer 120 to the second conductive barrier portion 111 is greater than 1 and less than or equal to 500.

[0149] In some embodiments, the thickness of the second conductive blocking portion 111 can be greater than or equal to 10 nm and less than 5 μm. This avoids the situation where the thickness of the second conductive blocking portion 111 is too small, resulting in insufficient blocking of deep-level elements and poor blocking effect, while also preventing excessive thickness from leading to excessive cost. In other words, this design ensures effective blocking while avoiding excessive cost.

[0150] Specifically, in such an embodiment, the thickness of the second conductive barrier portion 111 can be any value between greater than 10 nm and less than 5 μm, for example, one of the following: 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, and 4.9 μm.

[0151] In some embodiments, the second printing paste layer 120 may include at least one of a copper paste printing layer, an aluminum paste printing layer, a copper-aluminum paste printing layer, a silver-plated copper paste printing layer, a nickel-plated copper paste printing layer, and a tin-plated copper paste printing layer. Thus, using such a printing paste layer for the second printing paste layer 120 can reduce costs while ensuring the conductivity of the second printing paste layer 120.

[0152] Specifically, in such embodiments, the second printing paste layer 120 can be made of low-temperature paste. For example, the copper paste printing layer can be made of low-temperature copper paste, the aluminum paste printing layer can be made of low-temperature aluminum paste, and the copper-aluminum paste printing layer can be made of low-temperature copper-aluminum paste. During the manufacturing process, the low-temperature paste can be printed by means of screen printing or the like, and then cured by means of drying or the like. The second printing paste layer 120 only forms conductive contact with the second conductive barrier portion 111, and will not burn through the second portion 42 of the back passivation film layer 40 to contact the second doped layer 30.

[0153] In some embodiments, the second conductive barrier 111 may be at least one of a silver layer, an aluminum layer, a nickel layer, a titanium layer, an aluminum alloy layer, an aluminum-silicon alloy layer, an aluminum paste layer, a silver paste layer, a titanium alloy layer, a graphite layer, and a transparent conductive film layer. Thus, the second conductive barrier layer 51 can not only effectively block deep-level elements in the second printing paste layer 120, but also give it superior conductivity, improving carrier collection efficiency. At the same time, it is less likely to cause a significant reduction in the minority carrier lifetime in the bulk region.

[0154] Specifically, in some embodiments, the second conductive barrier portion 111 may be made of a burn-through paste, such as a burn-through silver paste, a burn-through aluminum paste, etc. In such cases, the second opening 421 may be formed by directly burning through a portion of the second portion 42 during the formation of the second conductive barrier portion 111.

[0155] Of course, in some embodiments, the second conductive barrier portion 111 can also be fabricated by PVD or other methods. For example, in some embodiments, the second conductive barrier portion 111 can be a PVD silver layer, PVD aluminum layer, or other film layer. For example, in some embodiments, a plurality of second openings 421 can be formed on the second portion 42 first, and then a silver layer or an aluminum layer can be deposited on the second openings 421 by PVD to form a plurality of isolated second conductive barrier portions 111. Then, the isolated second conductive barrier portions 111 are electrically connected together by printing a second printing paste layer 120.

[0156] Referring to Figure 9, in some embodiments, the back contact battery 100 may further include a third welding layer 130, which is disposed on the second printed paste layer 120 and is used for welding to the solder ribbon 210. Thus, by providing an additional welding layer on the second printed paste layer 120, the stability during the welding process of the solder ribbon 210 can be improved, avoiding poor weld formation and thus poor welding stability resulting from direct welding to the second printed paste layer 120.

[0157] Specifically, in such an embodiment, the third solder layer 130 may include at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, or an alloy layer containing tin and nickel. This allows for improved soldering performance with the solder ribbon 210 while simultaneously forming excellent conductive contact with the second printed paste layer 120.

[0158] Referring to Figure 9, in some embodiments, the back contact battery 100 may further include a third antioxidant protective layer 132, which is stacked on the second printing paste layer 120. The antioxidant capacity of the third antioxidant protective layer 132 is greater than that of the second printing paste layer 120. That is, the third welding layer 130 in Figure 9 is replaced by the third antioxidant protective layer 132. In this way, by setting the third antioxidant protective layer 132, the second printing paste layer 120 can be protected against oxidation, effectively preventing the second printing paste layer 120 from being exposed to air for a long time during the transportation and storage of the back contact battery 100, which would generate oxides and lead to a deterioration in welding performance and conductivity.

[0159] In some embodiments, the third antioxidant protective layer 132 may be a layer structure with excellent antioxidant properties. For example, it may include at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer. The third antioxidant protective layer 132 may also be formed on the second printing paste layer 120 by PVD deposition, inkjet printing, or other methods.

[0160] In some embodiments, the third antioxidant protective layer 132 can also be used for soldering with the solder ribbon, which can be soldered together with the second printing paste layer 120.

[0161] Referring to Figure 10, in some other embodiments, the back contact battery 100 may further include a second metal plating layer 140 stacked on the second printed paste layer 120. Thus, by providing the second metal plating layer 140 on the second printed paste layer 120, conductivity can be enhanced, transmission loss reduced, and the second printed paste layer 120 can be protected, improving its reliability and weather resistance.

[0162] In such an embodiment, the second metal plating layer 140 may include at least one of the following: electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer. Thus, by using electroplating or electroless plating to form the aforementioned types of metal plating layers, cost can be controlled while ensuring weldability and conductivity.

[0163] Please continue referring to Figure 10. In some embodiments, the back contact battery 100 may further include a fourth antioxidant protective layer 150 stacked on the second metal plating layer 140. The antioxidant capacity of the fourth antioxidant protective layer 150 is greater than that of the second metal plating layer 140. Thus, by providing the second metal plating layer 140, its welding performance when welded to the solder ribbon 210 can be guaranteed, while the fourth antioxidant protective layer 150 can protect the second metal plating layer 140, effectively preventing the second metal plating layer 140 from being exposed to air for a long time during transportation and storage, thus avoiding the formation of oxides and resulting in poor welding performance and conductivity. At the same time, it can also effectively prevent the phenomenon of organic matter, dust and other impurities adhering to the surface, which would lead to poor appearance and affect efficiency.

[0164] In some embodiments, the second metal plating layer 140 is preferably an electroplated copper layer. Electroplated copper layers have better solderability, lower cost, and better conductivity, which can improve the collection efficiency of charge carriers.

[0165] Specifically, it can be understood that the second metal plating layer 140 serves both as a welding layer and as a carrier collection layer via the second printed paste layer 120 and the second conductive barrier portion 111. It requires a relatively active metal for fabrication, such as the electroplated copper layer mentioned above. However, highly active metal plating layers are prone to oxidation, leading to poor subsequent welding performance. Therefore, this disclosure effectively avoids this situation by providing a fourth anti-oxidation protective layer 150 on the first metal seed layer.

[0166] Specifically, in such embodiments, the second metal plating layer 140 may be a highly active metal electroplating layer, such as an electroplated copper layer, and the fourth antioxidant protective layer 150 may be an inert metal layer. For example, in some embodiments, the fourth antioxidant protective layer 150 may include a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, or a metal oxide layer, which may be formed on the second metal plating layer 140 by means of PVD deposition, inkjet printing, etc.

[0167] Of course, in other embodiments, the fourth antioxidant protective layer 150 may also include an organic or inorganic film layer capable of resisting oxidation, such as an inorganic film layer with a chain structure. Specific details are not limited here, but an inert metal layer is preferred. That is, in this disclosure, the fourth antioxidant protective layer 150 may include at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

[0168] In some embodiments, the fourth antioxidant protective layer 150 may also be a magnetic layer. Thus, during the welding process with the solder ribbon 210, the fourth antioxidant protective layer 150 can adsorb the solder ribbon 210, effectively preventing the solder ribbon 210 from shifting during welding, improving the stability and reliability of the welding. In other words, the fourth antioxidant protective layer 150 can effectively prevent oxidation of the second metal plating layer 140 while also positioning and pre-fixing the solder ribbon 210 during the welding process.

[0169] Specifically, in such embodiments, the magnetic layer refers to a film layer that has magnetic adsorption function itself or a film layer that has magnetic adsorption function after being energized. The magnetic layer can be made entirely of magnetic materials.

[0170] Of course, it is understood that in some embodiments, the fourth antioxidant protective layer 150 may not be a magnetic layer made entirely of magnetic materials, but may contain magnetic material components. For example, magnetic materials may be added to inert metal layers such as the tin layer, nickel layer and metal oxide layer mentioned above, so that the antioxidant protective layer can generate magnetic attraction to the solder ribbon 210.

[0171] In addition, some metal particles may be spattered during the welding process. The magnetic attraction can be used to attract some of these metal particles, thereby reducing surface contamination of the solar cells, improving the light absorption capacity of the solar cells, and increasing the light conversion efficiency of the solar cells.

[0172] Referring to Figure 10, in some embodiments, instead of the fourth antioxidant protective layer 150, a fourth welding layer 152 may be provided on the first metal plating layer 80. In this case, the fourth welding layer 152 is stacked on the second metal plating layer 140 and is used for welding with the solder strip 210. That is, the fourth antioxidant protective layer 150 in Figure 10 is replaced by the fourth welding layer 152. Thus, the fourth welding layer 152 ensures the welding performance with the solder strip and also protects the second metal plating layer 140.

[0173] In such an embodiment, the fourth solder layer 152 may include at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, or an alloy layer containing tin and nickel. This allows for excellent electrical conductivity while ensuring solderability.

[0174] In some embodiments, only one continuous second opening 421 may be formed on the second portion 42. In such cases, the second conductive blocking structure includes only one second conductive blocking portion 111, which is disposed at the second opening 421.

[0175] Referring to Figures 8-10, in some embodiments, the second portion 42 may have multiple second openings 421, which are spaced apart along a second direction. The number of second conductive blocking portions corresponds one-to-one with the number of second openings 421, and the second printed paste layer 120 is electrically connected to all the second conductive blocking portions 111. Thus, by forming a plurality of spaced second openings 421 only in a portion of the second portion 42 and by providing second conductive blocking portions 111 only within the second openings 421, the proportion of the metallized region on the second doped layer 30 can be reduced, reducing recombination caused by metallization and improving the efficiency of the back contact battery 100.

[0176] Specifically, in the embodiments of this disclosure, the second conductive blocking portion 111 may be located only within the second opening 421 (as shown in Figures 8-10), or it may be partially located within the second opening 421, with the other part extending above the second portion 42 at the edge of the second opening 421. No specific limitation is made here.

[0177] Referring to Figures 8-10, in some embodiments, when the first portion 41 has several spaced second openings 421, each second conductive barrier portion 111 is independent of each other (i.e., not in direct contact). This reduces the amount of material used in the second conductive barrier structure, thus lowering costs.

[0178] Specifically, in such a case, the second conductive blocking portion 111 may be located only within the second opening 421. Of course, in some embodiments, the second conductive blocking portion 111 may also be a second portion 42 that partially protrudes from the second opening 421 and extends to the edge of the second opening 421. In such a case, the second printing paste layer 120 surrounds the portion of the second conductive blocking portion 111 that protrudes from the second opening 421.

[0179] Referring to Figure 11, in some embodiments, the second conductive barrier structure may further include a plurality of second conductive connection portions 112. Each second conductive connection portion 112 connects two adjacent second conductive barrier portions 111. The second conductive connection portions 112 are disposed on the second portion 42 and do not contact the second doped layer 30. Thus, by providing the second conductive connection portions 112, the plurality of second conductive barrier portions 111 can be connected into a single unit, increasing the contact area between the second conductive barrier structure and the second printing paste layer 120, thereby improving conductivity.

[0180] In some embodiments, in the second conductive barrier structure, the portion of the second conductive barrier 111 located within the second opening 421 and in contact with the second doped layer 30 has a length of 5 μm-5000 μm in the second direction, and the spacing between two adjacent second openings 421 in the second direction is 10 μm-2000 μm. This avoids the situation where the length of a single second conductive barrier 111 is too large, resulting in an excessively large metallization area and excessive recombination, thus affecting efficiency. It also avoids the situation where the length of a single second conductive barrier 111 is too small, resulting in an insufficient contact area with the second printed paste layer 120, which could easily lead to unstable contact.

[0181] Meanwhile, setting the spacing between two adjacent first openings within the aforementioned reasonable range can prevent the metallized area from becoming too large, and also prevent the spacing between two adjacent second openings 421 from becoming too large, which would cause excessively long carrier transport distances during collection and result in excessive transport losses. In other words, this setting can control the metallized area within a reasonable range, avoiding excessive metallization recombination losses and carrier transport losses, thereby balancing the relationship between recombination and transport losses caused by metallization, achieving a better matching effect, and thus improving the electrical performance of the back contact battery 100.

[0182] Specifically, in such an embodiment, the length of the portion of the second conductive barrier portion 111 located within the second opening 421 and in contact with the second doped layer 30 in the second direction can be any value between 5μm and 5000μm, for example, one of 5μm, 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 1000μm, 1500μm, 2000μm, 2500μm, 3000μm, 4000μm, and 5000μm.

[0183] The spacing between two adjacent second openings 421 in the second direction can be any value between 10μm and 2000μm, for example, one of 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 200μm, 300μm, 400μm, 500μm, 1000μm, 1500μm, and 2000μm.

[0184] Furthermore, in some embodiments, in the second conductive barrier structure, the length of the portion of the second conductive barrier 111 located within the second opening 421 and in contact with the second doped layer 30 in the second direction is preferably 10 μm-1000 μm, and the spacing between two adjacent second openings 421 in the second direction is 10 μm-1000 μm. This allows for a better matching effect between recombination and transport losses caused by metallization, further improving the electrical performance of the back contact battery 100.

[0185] Furthermore, in some embodiments, in the second conductive barrier structure, the length of the portion of the second conductive barrier portion 111 located within the second opening 421 and in contact with the second doped layer 30 in the second direction is preferably 10μm-500μm, and the spacing between two adjacent second openings 421 in the second direction is 10μm-500μm.

[0186] Specifically, in such an embodiment, in the second conductive barrier structure, the length of the portion of the second conductive barrier 111 located within the second opening 421 and in contact with the second doped layer 30 in the second direction is preferably 10 μm-100 μm, and the spacing between two adjacent second openings 421 in the second direction is 30 μm-500 μm. Most preferably, it is 10 μm-50 μm and 30 μm-300 μm.

[0187] That is to say, in this disclosure, in the second conductive barrier structure, the length of the portion of the second conductive barrier portion 111 located in the second opening 421 and in contact with the second doped layer 30 in the second direction is preferably 10μm-50μm, and the distance between two adjacent second openings 421 in the second direction is 30μm-300μm.

[0188] Specifically, through repeated research and demonstration by the inventors of this disclosure, by setting the above two values ​​within this optimal range, the recombination and transmission losses caused by metallization can achieve the best matching effect, and the performance of the back contact battery 100 can reach its optimal level.

[0189] Specifically, in such an embodiment, the length of the portion of the second conductive barrier 111 located within the second opening 421 and in contact with the second doped layer in the second direction can be any value between 10 μm and 50 μm, for example, one of 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm. The spacing between two adjacent second openings 421 in the second direction can be any value between 30 μm and 300 μm, for example, one of 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 200 μm, and 300 μm.

[0190] In some embodiments, in a single second conductive barrier structure, the ratio between the sum of the contact areas of all second conductive barrier portions 111 on the second doped layer and the area of ​​the second doped layer is greater than or equal to 0.0001 and less than 1. It should be noted that this area ratio refers to the ratio of the sum of the contact areas of all second conductive barrier portions 111 on the single second doped layer 30 to the area of ​​the single second doped layer 30. This avoids both excessively small metallization area on the second doped layer 30 leading to excessive carrier transport loss and excessively large metallization area leading to high metallization recombination affecting efficiency, thereby balancing the relationship between metallization recombination and carrier transport loss and optimizing the performance of the back contact battery 100.

[0191] Furthermore, in such an embodiment, the area ratio between the two is preferably 0.0001-0.5. This further optimizes the relationship between balancing metallization recombination and carrier transport losses, achieving a better matching effect.

[0192] In such embodiments, the ratio between the two is preferably 0.0001-0.1, more preferably 0.0005-0.05, and most preferably 0.0005-0.02. That is, in the embodiments of this disclosure, in a single second conductive barrier structure, the ratio between the sum of the contact areas of all the second conductive barrier portions 111 and the second doped layer 30 and the area of ​​the second doped layer 30 is most preferably greater than or equal to 0.0005 and less than or equal to 0.02.

[0193] Specifically, through repeated research and demonstration in this disclosure, by setting the ratio of the two above in the optimal range of 0.0005-0.02, the recombination and transmission losses caused by metallization can be optimally matched, and the performance and efficiency of the back contact battery 100 can be optimized.

[0194] Referring to Figure 12, in some embodiments, in the battery assembly 200, a plurality of solder ribbons 210 for connecting the various back contact batteries 100 in series may be spaced apart along a second direction and intersected with all the first doped layers 20 and the second doped layers 30. In two adjacent solder ribbons 210, one solder ribbon 210 is electrically connected to all the first printed paste layers 60 and insulated from the second printed paste layer 120 (when the back contact battery 100 has the first welding layer 70 mentioned above, it can be welded to the first welding layer 70; when the back contact battery 100 has the second welding layer 92 mentioned above, it can be welded to the second welding layer 92). 92 welding (when the back contact battery 100 has the first metal plating layer 80 mentioned above, it can be welded to the first metal plating layer 80), another welding strip 210 is electrically connected to all the second printing paste layers 120 and insulated from the first printing paste layer 60 (when the back contact battery 100 has the third welding layer 130 mentioned above, it can be welded to the third welding layer 130; when the back contact battery 100 has the fourth welding layer 152 mentioned above, it can be welded to the fourth welding layer 152; when the back contact battery 100 has the second metal plating layer 140 mentioned above, it can be welded to the second metal plating layer 140).

[0195] Referring to Figure 11, in some other embodiments, in the battery assembly 200, each first printed paste layer 60 may have a corresponding solder ribbon 210. When the back contact battery 100 has the first welding layer 70 mentioned above, the ribbon 210 can be welded to the first welding layer 70; when the back contact battery 100 has the second welding layer 92 mentioned above, the ribbon 210 can be welded to the second welding layer 92; and when the back contact battery 100 has the first metal plating layer 80 mentioned above, the ribbon 210 can be welded to the first metal plating layer 80. Each second metallization layer also has a corresponding solder ribbon 210. When the back contact battery 100 has the third welding layer 130 mentioned above, the ribbon 210 can be welded to the third welding layer 130; and when the back contact battery 100 has the second metal plating layer 140 mentioned above, the ribbon 210 can be welded to the second metal plating layer 140.

[0196] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with the described embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0197] Furthermore, the above description is merely a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A back-contact battery, comprising: A silicon wafer having opposing front and back sides; A first doped layer and a second doped layer are disposed on the back surface at intervals along a first direction and both extend along a second direction, the second direction intersecting the first direction, and the doping types of the first layer and the second layer are opposite. A back passivation film layer, wherein the back passivation film layer is at least stacked on the first doped layer and the second doped layer, the back passivation film layer includes a first portion stacked on the first doped layer, and at least one of the first portions has a first opening formed thereon; At least one first conductive barrier structure, the first conductive barrier structure including a first conductive barrier portion, the first conductive barrier portion being at least partially disposed within the first opening and in contact with the first doped layer; A first printing paste layer is disposed on the first portion and electrically connected to the first conductive barrier portion, wherein the thickness of the first printing paste layer is greater than the thickness of the first conductive barrier portion.

2. The back contact battery according to claim 1, wherein, The ratio between the thickness of the first printed paste layer and the thickness of the first conductive barrier portion is greater than 1 and less than or equal to 5000.

3. The back contact battery according to claim 2, wherein, The ratio between the thickness of the first printed paste layer and the thickness of the first conductive barrier portion is greater than 1 and less than or equal to 500.

4. The back contact battery according to claim 1, wherein, The back contact battery also includes a first antioxidant protective layer, which is stacked on the first printing paste layer.

5. The back contact battery according to claim 4, wherein, The first antioxidant protective layer includes at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

6. The back contact battery according to claim 1, wherein, The back contact battery also includes a first welding layer, which is stacked on the first printed paste layer and is used for welding with the solder strip.

7. The back contact battery according to claim 6, wherein, The first solder layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, and an alloy layer containing tin and nickel.

8. The back contact battery according to claim 1, wherein, The back contact battery also includes a first metal plating layer stacked on the first printed paste layer.

9. The back contact battery according to claim 8, wherein, The first metal plating layer includes at least one of electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer.

10. The back contact battery according to claim 8, wherein, The back contact battery also includes a second antioxidant protective layer or a second welding layer stacked on the first metal plating layer.

11. The back contact battery according to claim 10, wherein, The second antioxidant protective layer includes at least one of the following: a tin layer, a nickel layer, an alloy layer containing tin and copper, an alloy layer containing tin and nickel, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, a metal oxide layer, an organic film layer, and an inorganic film layer.

12. The back contact battery according to claim 10, wherein, In the case where the back contact battery includes the second solder layer, the second solder layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer containing tin and silver, an alloy layer containing tin and bismuth, an alloy layer containing tin and copper, and an alloy layer containing tin and nickel.

13. The back contact battery according to claim 1, wherein, The first conductive barrier includes at least one of a silver layer, an aluminum layer, a nickel layer, a titanium layer, an aluminum metal alloy layer, an aluminum-silicon alloy layer, an aluminum paste layer, a silver paste layer, a titanium alloy layer, a graphite layer, and a transparent conductive film layer.

14. The back contact battery according to claim 1, wherein, The first printing paste layer includes at least one of copper paste printing layer, aluminum paste printing layer, copper-aluminum paste printing layer, silver-plated copper paste printing layer, nickel-plated copper paste printing layer, and tin-plated copper paste printing layer.

15. The back contact battery according to claim 1, wherein, In the first part, there are multiple first openings, which are spaced apart along the second direction. The number of first conductive blocking portions corresponds one-to-one with the number of first openings. The first printing paste layer is electrically connected to all the first conductive blocking portions.

16. The back contact battery according to claim 15, wherein, The back contact battery satisfies one of the following: each of the first conductive blocking portions is independent of each other; the first conductive blocking structure further includes a plurality of first conductive connecting portions, the first conductive connecting portions connecting two adjacent first conductive blocking portions, the first conductive connecting portions being disposed on the first portion and not in contact with the first doped layer.

17. The back contact battery according to claim 15, wherein, In the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is μm-5000μm, and the distance between two adjacent first openings in the second direction is 10μm-2000μm.

18. The back contact battery according to claim 17, wherein, In the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is 10μm-500μm, and the spacing between two adjacent first openings in the second direction is 10μm-500μm.

19. The back contact battery according to claim 18, wherein, In the first conductive barrier structure, the length of the portion of the first conductive barrier located within the first opening and in contact with the first doped layer in the second direction is 10μm-50μm, and the distance between two adjacent first openings in the second direction is 30μm-300μm.

20. The back contact battery according to claim 15, wherein, In a single first conductive barrier structure, the ratio between the sum of the contact areas of all the first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is greater than or equal to 0.0001 and less than 1.

21. The back contact battery according to claim 20, wherein, In a single first conductive barrier structure, the ratio between the sum of the contact areas of all the first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is 0.0001-0.

1.

22. The back contact battery according to claim 21, wherein, In a single first conductive barrier structure, the ratio between the sum of the contact areas of all the first conductive barrier portions with the first doped layer and the area of ​​the first doped layer is 0.0005-0.

02.

23. The back contact battery according to claim 1, wherein, The back contact battery satisfies at least one of the following: the thickness of the first printed paste layer is 5μm-50μm; The thickness of the first conductive barrier is greater than or equal to 10 nm and less than 5 μm.

24. The back contact battery according to any one of claims 1-23, wherein, The back passivation film layer further includes a second portion stacked on the second doped layer, and at least one of the second portions has a second opening formed thereon; The back contact battery also includes: At least one second conductive barrier structure, the second conductive barrier structure including a plurality of second conductive barrier portions, the second conductive barrier portions being at least partially disposed within the second opening and in contact with the second doped layer; A second printing paste layer is disposed on the second portion and is electrically connected to all the second conductive blocking portions.

25. The back contact battery according to claim 24, wherein, The thickness of the second printing paste layer is greater than the thickness of the second conductive barrier portion.

26. The back contact battery according to claim 25, wherein, The ratio between the thickness of the second printed paste layer and the thickness of the second conductive barrier is greater than 1 and less than 5000.

27. The back contact battery according to claim 26, wherein, The ratio between the thickness of the second printed paste layer and the thickness of the second conductive barrier is greater than 1 and less than 500.

28. The back contact battery according to claim 24, wherein, The back contact battery also includes a third antioxidant protective layer, which is stacked on the second printing paste layer.

29. The back contact battery according to claim 24, wherein, The back contact battery also includes a third welding layer, which is stacked on the second printing paste layer and is used for welding with the solder strip.

30. The back contact battery according to claim 24, wherein, The back contact battery also includes a second metal plating layer stacked on the second printed paste layer.

31. The back contact battery according to claim 30, wherein, The second metal plating layer includes at least one of electroplated copper layer, electroplated nickel layer, electroplated copper-tin alloy layer, electroplated copper-silver alloy layer, electroless copper plating layer, electroless nickel plating layer, electroless copper-tin alloy layer, and electroless copper-silver alloy layer.

32. The back contact battery according to claim 30, wherein, The back contact battery also includes a fourth antioxidant protective layer or a fourth welding layer stacked on the second metal plating layer.

33. The back contact battery according to claim 24, wherein, In the second part, there are multiple second openings, which are spaced apart along the second direction. The number of second conductive blocking portions corresponds one-to-one with the number of second openings. The second printing paste layer is electrically connected to all the second conductive blocking portions.

34. The back contact battery according to claim 33, wherein, The back contact battery satisfies one of the following: each of the second conductive blocking portions is independent of each other; the second conductive blocking structure further includes a plurality of second conductive connecting portions, the second conductive connecting portions connecting two adjacent second conductive blocking portions, and the second conductive blocking portions being disposed on the second portion and not in contact with the second doped layer.

35. The back contact battery according to claim 33, wherein, In the second conductive barrier structure, the portion of the second conductive barrier located within the second opening and in contact with the second doped layer has a length of 5μm-5000μm in the second direction, and the spacing between two adjacent second openings in the second direction is 10μm-2000μm.

36. The back contact battery according to claim 35, wherein, In the second conductive barrier structure, the portion of the second conductive barrier located within the second opening and in contact with the second doped layer has a length of 10μm-500μm in the second direction, and the spacing between two adjacent second openings in the second direction is 10μm-500μm.

37. The back contact battery according to claim 36, wherein, In the second conductive barrier structure, the portion of the second conductive barrier located within the second opening and in contact with the second doped layer has a length of 10μm-50μm in the second direction, and the spacing between two adjacent second openings in the second direction is 30μm-300μm.

38. The back contact battery according to claim 24, wherein, In a single second conductive barrier structure, the ratio between the sum of the contact areas of all the second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is greater than or equal to 0.0001 and less than 1.

39. The back contact battery according to claim 38, wherein, In a single second conductive barrier structure, the ratio between the sum of the contact areas of all the second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is 0.0001-0.

1.

40. The back contact battery according to claim 39, wherein, In a single second conductive barrier structure, the ratio between the sum of the contact areas of all the second conductive barrier portions with the second doped layer and the area of ​​the second doped layer is 0.0005-0.

02.

41. The back contact battery according to claim 24, wherein, The back contact battery satisfies at least one of the following: the thickness of the second printed paste layer is 5μm-50μm; The thickness of the second conductive barrier is greater than or equal to 10 nm and less than 5 μm.

42. A battery assembly, characterized in that, Includes the back contact battery as described in any one of claims 1-41.

43. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 42.

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