Back contact cell, cell assembly and photovoltaic system

Abstract

The invention is suitable for the technical field of solar cells, and provides a back contact cell, a cell assembly and a photovoltaic system, in the back contact cell, a first opening is formed in a first part, located on a first doping layer, in a back passivation film layer, a first conductive blocking part is arranged at the first opening, a first printing paste layer is arranged on the first part, and a second conductive blocking part is arranged at the second part. The first printing paste layer is electrically connected with the first conductive blocking part. Thus, through the arrangement of the first conductive blocking part and the first printing slurry layer, the blocking function of the first conductive blocking part can reduce the probability that deep-energy-level elements in the first printing slurry layer enter the first doping layer and the silicon wafer and even completely block the deep-energy-level elements, the defects caused by introduction of the deep-energy-level elements are reduced, and the yield of the silicon wafer is improved. Therefore, the electrical performance of the back contact battery is ensured. Meanwhile, the thickness of the first printing paste layer is set to be larger than that of the first conductive blocking part, so that the transverse conductive performance of the back contact battery can be improved, the transmission loss is reduced, and the electrical performance and efficiency are further improved.

Description

Technical Field

[0001] The present application relates to the technical field of solar cells, and in particular to a back-contact cell, a cell string, a cell assembly and a photovoltaic system. Background Art

[0002] A back-contact solar cell is a cell in which both the emitter and base contact electrodes are placed on the back of the cell. The light-receiving surface of the cell is not blocked by any metal electrodes, thereby effectively improving the efficiency of the cell.

[0003] In the related art, a P-type doped layer and an N-type doped layer are provided on the back of a back-contact solar cell, a P-type electrode is provided on the P-type doped layer, and an N-type electrode is provided on the N-type doped layer. However, the electrical performance and efficiency of the back-contact solar cell in the prior art need to be improved. Summary of the invention

[0004] The present application provides a back-contact cell, a cell assembly and a photovoltaic system.

[0005] The present application is implemented in this way. The back contact battery of the embodiment of the present application includes:

[0006] A silicon wafer having a front side and a back side facing each other;

[0007] a first doping layer and a second doping layer, wherein the first doping layer and the second doping layer are arranged on the back surface at intervals along a first direction and both extend along a second direction, the second direction intersects the first direction, and the first doping layer and the second doping layer have opposite doping types;

[0008] a back passivation film layer, the back passivation film layer being stacked on at least the first doping layer and the second doping layer, the back passivation film layer comprising a first portion stacked on the first doping layer, and a first opening being formed on at least one of the first portions;

[0009] at least one first conductive barrier structure, the first conductive barrier structure comprising 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;

[0010] A first printing paste layer is provided on the first portion and is electrically connected to the first conductive barrier, wherein a thickness of the first printing paste layer is greater than a thickness of the first conductive barrier.

[0011] In some embodiments, a ratio between a thickness of the first printing paste layer and a thickness of the first conductive barrier portion is greater than 1 and less than or equal to 5,000.

[0012] In some embodiments, a ratio between a thickness of the first printing paste layer and a thickness of the first conductive barrier portion is greater than 1 and less than or equal to 500.

[0013] In some embodiments, the back contact battery further includes a first anti-oxidation protection layer, and the first anti-oxidation protection layer is stacked on the first printing paste layer.

[0014] In some embodiments, the first anti-oxidation protective layer includes at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer or an inorganic film layer.

[0015] In some embodiments, the back contact battery further includes a first welding layer, which is stacked on the first printing paste layer, and the first welding layer is used for welding with a welding ribbon.

[0016] 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 comprising tin and silver, an alloy layer comprising tin and bismuth, an alloy layer comprising tin and copper, and an alloy layer comprising tin and nickel.

[0017] In some embodiments, the back contact battery further includes a first metal plating layer stacked on the first printing paste layer.

[0018] In some embodiments, the first metal plating layer includes at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

[0019] In some embodiments, the back contact battery further includes a second anti-oxidation protection layer or a second welding layer stacked on the first metal plating layer.

[0020] In some embodiments, the second anti-oxidation layer protection includes at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer or an inorganic film layer.

[0021] 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 comprising tin and silver, an alloy layer comprising tin and bismuth, an alloy layer comprising tin and copper, and an alloy layer comprising tin and nickel.

[0022] In some embodiments, the first conductive barrier comprises 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.

[0023] In some embodiments, the first printing paste layer includes at least one of a copper paste printing layer, an aluminum paste printing layer, a copper-aluminum paste printing layer, a silver-coated copper paste printing layer, a nickel-coated copper paste printing layer, and a tin-coated copper paste printing layer.

[0024] In some embodiments, on the first part, the number of the first openings is multiple, the multiple first openings are arranged at intervals along the second direction, the number of the first conductive blocking parts corresponds one-to-one to the number of the first openings, and the first printing paste layer is electrically connected to all the first conductive blocking parts.

[0025] In some embodiments, each of the first conductive blocking portions is independent of each other; or, the first conductive blocking structure also includes a plurality of first conductive connecting portions, which connect two adjacent first conductive blocking portions, and the first conductive connecting portions are arranged on the first portion and are not in contact with the first doping layer.

[0026] In some embodiments, in the first conductive barrier structure, a portion of the first conductive barrier portion located in the first opening and in contact with the first doping layer has a length of 5um-5000um in the second direction, and a distance between two adjacent first openings in the second direction is 10um-2000um.

[0027] In some embodiments, in the first conductive barrier structure, the length of the first conductive barrier portion located in the first opening and in contact with the first doping layer in the second direction is 10um-500um, and the distance between two adjacent first openings in the second direction is 10um-500um.

[0028] In some embodiments, in the first conductive barrier structure, the length of the first conductive barrier portion located in the first opening and in contact with the first doping layer in the second direction is 10um-50um, and the distance between two adjacent first openings in the second direction is 30um-300um.

[0029] In some embodiments, in a single first conductive barrier structure, a ratio of a sum of contact areas of all the first conductive barrier portions with the first doping layer to an area of ​​the first doping layer is greater than or equal to 0.0001 and less than 1.

[0030] In some embodiments, in a single first conductive barrier structure, a ratio between a sum of contact areas of all the first conductive barrier portions with the first doping layer and an area of ​​the first doping layer is 0.0001-0.1.

[0031] In some embodiments, in a single first conductive barrier structure, a ratio between a sum of contact areas of all the first conductive barrier portions with the first doping layer and an area of ​​the first doping layer is 0.0005-0.02.

[0032] In some embodiments, the thickness of the first printing paste layer is 5um-50um; and / or

[0033] The thickness of the first conductive barrier portion is greater than or equal to 10 nm and less than 5 um.

[0034] In some embodiments, the back passivation film layer further includes a second portion stacked on the second doping layer, and a second opening is formed on at least one of the second portions;

[0035] The back contact battery further comprises:

[0036] at least one second conductive barrier structure, the second conductive barrier structure comprising 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;

[0037] A second printing paste layer is disposed on the second portion and is electrically connected to all of the second conductive barrier portions.

[0038] In some embodiments, a thickness of the second printing paste layer is greater than a thickness of the second conductive barrier.

[0039] In some embodiments, a ratio between a thickness of the second printing paste layer and a thickness of the second conductive barrier portion is greater than 1 and less than 5,000.

[0040] In some embodiments, a ratio between a thickness of the second printing paste layer and a thickness of the second conductive barrier portion is greater than 1 and less than 500.

[0041] In some embodiments, the back contact battery further includes a third anti-oxidation protection layer, and the third anti-oxidation protection layer is stacked on the second printing paste layer.

[0042] In some embodiments, the back contact battery further includes a third welding layer, the third welding layer is stacked on the second printing paste layer, and the third welding layer is used for welding with a welding ribbon.

[0043] In some embodiments, the back contact battery further includes a second metal plating layer stacked on the second printing paste layer.

[0044] In some embodiments, the second metal plating layer includes at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

[0045] In some embodiments, the back contact battery further includes a fourth anti-oxidation protection layer or a fourth welding layer stacked on the second metal plating layer.

[0046] In some embodiments, on the second part, the number of the second openings is multiple, the multiple second openings are arranged at intervals along the second direction, the number of the second conductive blocking parts corresponds one-to-one to the number of the second openings, and the second printing paste layer is electrically connected to all the second conductive blocking parts.

[0047] In some embodiments, each of the second conductive blocking portions is independent of each other; or, the second conductive blocking structure also 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 are arranged on the second portion and are not in contact with the second doped layer.

[0048] In some embodiments, in the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 5um-5000um, and the distance between two adjacent second openings in the second direction is 10um-2000um.

[0049] In some embodiments, in the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 10um-500um, and the distance between two adjacent second openings in the second direction is 10um-500um.

[0050] In some embodiments, in the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 10um-50um, and the distance between two adjacent second openings in the second direction is 30um-300um.

[0051] In some embodiments, in a single second conductive barrier structure, a ratio between a sum of contact areas of all the second conductive barrier portions with the second doping layer and an area of ​​the second doping layer is greater than or equal to 0.0001 and less than 1.

[0052] In some embodiments, in a single second conductive barrier structure, a ratio between a sum of contact areas of all the second conductive barrier portions with the second doping layer and an area of ​​the second doping layer is 0.0001-0.1.

[0053] In some embodiments, in a single second conductive barrier structure, a ratio between a sum of contact areas of all the second conductive barrier portions with the second doping layer and an area of ​​the second doping layer is 0.0005-0.02.

[0054] In some embodiments, the thickness of the second printing paste layer is 5um-50um; and / or

[0055] The thickness of the second conductive barrier is greater than or equal to 10 nm and less than 5 um.

[0056] The present application also provides a battery assembly, which includes several of the above-mentioned back-contact batteries.

[0057] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0058] In the back contact battery, battery assembly and photovoltaic system in the embodiment of the present application, a first opening is formed on the first part of the back passivation film layer located on the first doped layer, a first conductive barrier is provided at the first opening, a first printing paste layer is provided on the first part, and the first printing paste layer is electrically connected to the first conductive barrier to achieve the output of current. In this way, through the arrangement of the first conductive barrier and the first printing paste layer, the blocking function of the first conductive barrier can reduce the probability of deep energy level elements in the first printing paste layer entering the first doped layer and the silicon wafer, or even completely block the deep energy level elements, reduce the defects introduced by the deep energy level elements, and thus ensure the electrical performance of the back contact battery. At the same time, the arrangement of the first printing paste layer can achieve the convergence output of the current, and setting the thickness of the first printing paste layer to be greater than the thickness of the first conductive barrier can improve the lateral conductivity of the back contact battery, reduce the transmission loss, and further improve the electrical performance and efficiency of the back contact battery.

[0059] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a module schematic diagram of the photovoltaic system provided in an embodiment of the present application.

[0061] Figure 2 It is a module schematic diagram of the battery assembly provided in an embodiment of the present application.

[0062] Figure 3 is a schematic diagram of the planar structure of a back contact battery provided in an embodiment of the present application;

[0063] Figure 4 yes Figure 3 Schematic diagram of the cross-sectional structure of the back contact battery along line IV-IV;

[0064] Figure 5 yes Figure 3 Another schematic diagram of the cross-sectional structure of the back contact battery along line IV-IV;

[0065] Figure 6 yes Figure 3 Another schematic cross-sectional structure diagram of the back contact battery along line IV-IV;

[0066] Figure 7 yes Figure 3 Another schematic cross-sectional structure diagram of the back contact battery along line IV-IV;

[0067] Figure 8 yes Figure 3 Schematic diagram of the cross-sectional structure of the back contact cell along line VIII-VIII;

[0068] Fig. 9 yes Figure 3 Another schematic diagram of the cross-sectional structure of the back contact cell along line VIII-VIII;

[0069] Fig.10 yes Figure 3 Another schematic cross-sectional structure diagram of the back contact cell along line VIII-VIII;

[0070] Fig.11 yes Figure 3 Another schematic cross-sectional structure diagram of the back contact cell along line VIII-VIII;

[0071] Fig.12 is a schematic diagram of a planar structure of a back contact battery provided in an embodiment of the present application when a welding strip is provided;

[0072] Fig.13 This is another planar structural schematic diagram of a back-contact battery provided in an embodiment of the present application when a welding strip is provided.

[0073] Description of main component symbols:

[0074] Photovoltaic system 1000, battery assembly 200, back contact battery 100, silicon wafer 10, front side 11, back side 12, first doping layer 20, second doping layer 30, back side passivation film layer 40, first part 41, first opening 411, second part 42, second opening 421, first conductive barrier 51, first conductive connection 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 111, second conductive connection 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 DESCRIPTION

[0075] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application is further described in detail below 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 throughout represent the same or similar elements or elements with the same or similar functions. It should be noted that the embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limiting the present application. In addition, it should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0076] In the description of the present application, it should be understood that the terms "up", "down", "left", "right", "horizontal", "vertical", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0077] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "several" is two or more, unless otherwise clearly and specifically defined.

[0078] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0079] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, and does not indicate the relationship between the various embodiments and / or settings discussed in itself. In addition, the various specific processes and examples of materials provided by the present application, but those of ordinary skill in the art can be aware of the application of other processes and / or the use scenarios of other materials.

[0080] See also Figure 1 and Figure 2 The photovoltaic system 1000 in the embodiment of the present application may include the battery assembly 200 in the embodiment of the present application, and the battery assembly 200 in the embodiment of the present application may include several back-contact batteries 100 in the embodiment of the present application.

[0081] In the embodiment of the present application, a plurality of back-contact cells 100 in a battery assembly 200 may be connected in series to form a plurality of battery strings, and each battery string may be connected in series, in parallel, or in a combination of series and parallel to realize current convergence output, for example, Fig.12 and Fig.13 As shown, the connection between the individual cells can be achieved by welding the welding strip 210, and the connection between the individual cell strings can be achieved by bus bars. In some embodiments, the individual cell strings can form a cell array, which is then packaged together by a front plate, a front film, a rear film, and a back plate to form a battery assembly 200.

[0082] See also Figure 3 and Figure 4 The back contact cell 100 in the embodiment of the present application may include a silicon wafer 10 , a first doping layer 20 , a second doping layer 30 , a back passivation film layer 40 , a first conductive barrier structure and a first printing paste layer 60 .

[0083] The silicon wafer 10 has a front side 11 and a back side 12 opposite to each other. The first doping layer 20 and the second doping layer 30 are arranged on the back side 12 at intervals along a first direction and both extend along a second direction, the second direction intersecting the first direction. The first doping layer 20 and the second doping layer 30 have opposite doping types, one of which is a P-type doping layer and the other is an N-type doping layer. In some embodiments, the back contact battery 100 has a plurality of first doping layers 20 and a plurality of second doping layers 30, and the plurality of first doping layers 20 and the plurality of second doping layers 30 can be arranged alternately along the first direction. Figure 3 As shown, in some embodiments, the first direction and the second direction may be the longitudinal direction and the lateral direction of the back contact battery 100, respectively, and the two directions are perpendicular to each other. Of course, in other embodiments, the first direction and the second direction may also be other directions, for example, two diagonal directions of the battery sheet, which is not specifically limited here.

[0084] It should be noted that, in the present application, in some embodiments, the first doping layer 20 and the second doping layer 30 may be directly located in the silicon wafer 10. For example, they may be directly diffused on the silicon wafer 10, thereby directly forming the first doping layer 20 and the second doping layer 30 in the silicon wafer 10. In other embodiments, the first doping layer 20 and the second doping layer 30 may also be both disposed on the silicon wafer 10. For example, both may be formed on the silicon wafer 10 by deposition. Of course, in some embodiments, one of the first doping layer 20 and the second doping layer 30 may also be located in the silicon wafer 10, and the other may be located on the silicon wafer 10, which is not specifically limited here.

[0085] The back passivation film layer 40 is at least stacked on the first doping layer 20 and the second doping layer 30. In some embodiments, the back passivation film layer 40 can completely cover the back side 12 of the entire silicon wafer 10. Figure 4 As shown, the back passivation film layer 40 may include a first portion 41 stacked on the first doping layer 20 (ie, a portion of the back passivation film layer 40 corresponding to the first doping layer 20 ), and a first opening 411 is formed on the first portion 41 .

[0086] like Figure 4 As shown, the number of the first conductive barrier structure is at least one, and the first conductive barrier structure includes a first conductive barrier portion 51 . The first conductive barrier portion 51 is at least partially disposed in the first opening 411 and in contact with the first doping layer 20 .

[0087] The first printing paste layer 60 is disposed on the first portion 41 of the back passivation film layer 40 and is electrically connected to the first conductive barrier 51, and the thickness of the first printing paste layer 60 is greater than the thickness of the first conductive barrier 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.

[0088] It should be noted that in the embodiment of the present application, the function of the first conductive blocking portion 51 is to effectively block the deep energy level elements in the first printing paste layer 60 while forming a conductive ohmic contact with the first doping layer 20, thereby reducing the probability of the deep energy level elements in the first printing paste layer 60 entering the doping layer or even the silicon wafer 10.

[0089] In the back contact cell 100, the cell assembly 200 and the photovoltaic system 1000 in the embodiment of the present application, a first opening 411 is formed on the first portion 41 on the first doping layer 20 in the back passivation film layer 40, a first conductive barrier 51 is provided at the first opening 411, a first printing paste layer 60 is provided on the first portion 41, and the first printing paste layer 60 is electrically connected to the first conductive barrier 51 to achieve the output of current. In this way, through the arrangement of the first conductive barrier 51 and the first printing paste layer 60, the blocking function of the first conductive barrier 51 can reduce the probability of deep energy level elements in the first printing paste layer 60 entering the first doping layer 20 and the silicon wafer 10, or even completely block the deep energy level elements, reduce the defects introduced by the deep energy level elements, and thus ensure the electrical performance of the back contact cell 100. At the same time, the first printing paste layer 60 can realize the current converging output, and the thickness of the first printing paste layer 60 is set to be greater than the thickness of the first conductive barrier 51, which can improve the lateral conductivity of the back contact battery 100, reduce the transmission loss, and further improve the electrical performance and efficiency of the back contact battery 100. That is to say, in the technical solution of the present application, while improving the lateral conductivity to reduce the transmission loss, the deep energy level elements in the first printing paste layer 60 can be effectively blocked from entering the first doping layer 20 and the silicon wafer 10, thereby further improving the performance of the back contact battery 100 and improving the efficiency of the back contact battery 100.

[0090] Specifically, in the embodiment of the present application, the silicon wafer 10 can be a single crystal silicon wafer or a polycrystalline silicon wafer, and it can be a P-type silicon wafer or an N-type silicon wafer, which is not specifically limited here. 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, which can be a single-layer film structure or a multi-layer film structure with two or more layers, which is not specifically limited here.

[0091] In addition, in the present application, it is preferred that the first opening 411 is provided on all the first portions 41 on the first doping layer 20, and the first conductive barrier 51 is located at the first opening 411. Of course, in some embodiments, the first opening 411 may be provided on some of the first portions 41 on the first doping layer 20, which is not specifically limited here. In the present application, the first conductive barrier structure may be provided on all the first portions 41, or only on some of the first portions 41, which is not specifically limited here.

[0092] It should be noted that, in the embodiment of the present application, the first printing paste layer 60 refers to a paste layer formed by screen printing with a paste, rather than a film layer formed by PVD coating or the like in the field of solar energy technology.

[0093] In some embodiments, a ratio between the thickness of the first printing paste layer 60 and the thickness of the first conductive barrier 51 is greater than 1 and less than or equal to 5,000.

[0094] Thus, by setting the thickness ratio of the two within this reasonable range, the cost can be controlled while ensuring the barrier performance of the first conductive barrier 51 and improving the lateral conductive performance.

[0095] Specifically, in such an embodiment, the thickness ratio between the two may be, for example, 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.

[0096] Further, in such an embodiment, the ratio between the thickness of the first printing paste layer 60 and the thickness of the first conductive barrier 51 is preferably greater than 1 and less than or equal to 500. Thus, by setting the thickness ratio of the two within this preferred range, the barrier performance and the lateral conductive performance can be ensured while reducing the cost as much as possible.

[0097] Specifically, in such an embodiment, the thickness ratio between the two may be, for example, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 or other values ​​greater than 1 and less than 500, without limitation herein.

[0098] In some embodiments, the thickness of the first printing paste layer 60 may be 5 um-50 um.

[0099] Thus, by setting the thickness of the first printing paste layer 60 within this reasonable range, it is possible to avoid the effect of improving the lateral conductivity performance being not as expected due to its too low thickness, and to avoid the cost being too high due to its too thick thickness. In other words, such a setting can improve the lateral conductivity and reduce the transmission loss while controlling the cost.

[0100] Specifically, in such an embodiment, the thickness of the first printing paste layer 60 may be, for example, 5um, 6um, 7um, 8um, 9um, 10um, 15um, 20um, 25um, 35um, 40um, 45um, 50um or any value between 5um-50um.

[0101] In such an embodiment, the thickness of the first conductive barrier 51 follows the ratio rule described above, and preferably, the thickness ratio of the first printing paste layer 60 to the first conductive barrier 51 is greater than 1 and meets or is equal to 500.

[0102] In some embodiments, the thickness of the first conductive barrier 51 may be greater than or equal to 10 nm and less than 5 μm. In this way, it can be shown that the thickness of the first conductive barrier 51 is too small to fully block the deep energy level elements, resulting in poor blocking effect, and it can also avoid being too thick and causing high cost. In other words, such a setting can ensure the blocking effect while avoiding high cost.

[0103] Specifically, in such an embodiment, the thickness of the first conductive barrier 51 may be, for example, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1um, 1.5um, 2um, 2.5um, 3um, 3.5um, 4um, 4.5um, 4.9um or any value greater than 10nm and less than 5um.

[0104] 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-coated copper paste printing layer, a nickel-coated copper paste printing layer, and a tin-coated copper paste printing layer.

[0105] Thus, the first printing paste layer 60 adopts such a printing paste layer, which can reduce the cost while ensuring the conductive performance of the first printing paste layer 60 .

[0106] Specifically, in such an embodiment, 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 screen printing or the like, and then the low-temperature paste is cured by drying or the like, and the first printing paste layer 60 only forms a conductive contact with the first conductive barrier 51, and does not burn through the first portion 41 of the back passivation film layer 40 to contact the first doping layer 20.

[0107] In some embodiments, the first conductive barrier 51 may be 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.

[0108] In this way, the first conductive barrier layer 51 can not only effectively block the deep energy level elements in the first printing paste layer 60, but also make it have better conductivity and improve the carrier collection efficiency. At the same time, it itself is not easy to cause a significant reduction in the minority carrier lifetime in the body region.

[0109] Specifically, in some embodiments, the first conductive barrier 51 may be made of a burn-through paste, for example, a burn-through silver paste, a burn-through aluminum paste, etc. In this case, the first opening 411 may be formed directly by burning through a partial area of ​​the first part 41 during the process of forming the first conductive barrier 51.

[0110] Of course, in some embodiments, the first conductive barrier 51 can also be prepared by PVD or other methods. For example, in some embodiments, the first conductive barrier 51 can be a film layer such as a PVD silver layer or a PVD aluminum layer. For example, in some embodiments, a plurality of first openings 411 can be formed on the first portion 41, and then a silver layer or an aluminum layer is plated at the first openings 411 by PVD to form a plurality of isolated first conductive barrier 51, and then the isolated first conductive barrier 51 is electrically connected together by printing the first printing paste layer 60.

[0111] See also Figure 5 In some embodiments, the back contact battery 100 may further include a first welding layer 70 , which is disposed on the first printing paste layer 60 , and the first welding layer 70 is used for welding with the welding ribbon 210 .

[0112] Thus, by further arranging a welding layer on the first printing paste layer 60 , it is possible to improve the stability during welding of the welding strip 210 , thereby preventing the first printing paste layer 60 from directly welding with poor welding formation and resulting in poor welding stability.

[0113] 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 including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel. In this way, the soldering performance with the soldering ribbon 210 can be improved while forming an excellent conductive contact with the first printing paste layer 60.

[0114] See also Figure 5 In some embodiments, the back contact battery 100 may further include a first anti-oxidation protection layer 72, which is stacked on the first printing paste layer 60. The anti-oxidation capacity of the first anti-oxidation protection layer 72 is greater than that of the first printing paste layer 60. Figure 5 The first welding layer 70 is replaced by a first anti-oxidation protection layer 72 .

[0115] In this way, by setting the first anti-oxidation protection layer 72, the first printed paste layer 60 can be protected from oxidation, effectively preventing the first printed paste layer 60 from being exposed to the air for a long time during the transportation and storage of the back contact battery 100 to generate oxides, thereby causing the welding performance and the conductive performance to deteriorate.

[0116] In some embodiments, the first anti-oxidation protective layer 72 may be a layer structure with excellent anti-oxidation performance, for example, it may include at least one of a tin layer, a nickel layer, an alloy layer including tin and copper, an alloy layer including tin and nickel, an alloy layer including tin and silver, an alloy layer including tin and bismuth, a metal oxide layer, an organic film layer, or an inorganic film layer. The first anti-oxidation protective layer 72 may be formed on the first printing paste layer 60 by PVD deposition, inkjet, or the like.

[0117] In some embodiments, the first anti-oxidation film layer 90 may also be used for welding with a welding ribbon, and the first anti-oxidation film layer 90 may be welded with the welding ribbon together with the first printing paste layer 60 .

[0118] See also Figure 6 In some other embodiments, the back contact battery 100 may further include a first metal plating layer 80 stacked on the first printing paste layer 60 .

[0119] Thus, by providing the first metal plating layer 80 on the first printing paste layer 60 , the conductive performance can be enhanced and the transmission loss can be reduced. Meanwhile, the first printing paste layer 60 can be protected and the reliability and weather resistance of the first printing paste layer 60 can be improved.

[0120] In such an embodiment, the first metal plating layer 80 may include at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

[0121] Thus, the above-mentioned type of metal coating is formed by electroplating or chemical plating, which can control the cost while ensuring the welding performance and conductive performance.

[0122] Please continue reading Figure 6 In some embodiments, the back contact battery 100 may further include a second anti-oxidation protection layer stacked on the first metal plating layer. The second anti-oxidation protection layer 90 has an anti-oxidation capability greater than that of the first metal plating layer 80.

[0123] In this way, by setting the first metal coating 80, its welding performance with the welding strip 210 can be guaranteed, and the second anti-oxidation protective layer 90 can protect the first metal coating 80, effectively preventing the first metal coating 80 from being exposed to the air for a long time during the transportation and storage of the back contact battery 100 to generate oxides, thereby causing the welding performance and the conductive performance to deteriorate. At the same time, it can also effectively prevent the phenomenon of organic matter, dust and other impurities adhering to the surface, resulting in poor appearance and affecting efficiency.

[0124] In some embodiments, the first metal plating layer 80 may be preferably an electroplated copper layer. The electroplated copper layer has better welding performance, lower cost, and better electrical conductivity, which can improve the collection efficiency of carriers.

[0125] Specifically, it can be understood that the first metal plating layer 80 plays a role in welding and collects carriers through the first printing paste layer 60 and the first conductive barrier 51. It needs to be made of a relatively active metal, such as the electroplated copper layer mentioned above. However, the highly active metal plating layer is prone to oxidation, resulting in poor subsequent welding performance. Therefore, the present application can effectively avoid such a situation by providing a second anti-oxidation protective layer 90 on the first metal seed layer.

[0126] Specifically, in such an embodiment, the first metal plating layer 80 may be a metal electroplating layer with strong activity, 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 a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, and a metal oxide layer, which can be formed on the first metal plating layer 80 by PVD deposition, inkjet, etc.

[0127] Of course, in other embodiments, the second anti-oxidation protective layer 90 may also include an organic film layer or an inorganic film layer capable of resisting oxidation, such as an inorganic film layer having a chain structure, which is not specifically limited here, and is preferably an inert metal layer. That is, in the present application, the second anti-oxidation protective layer 90 may include at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer, or an inorganic film layer.

[0128] In some embodiments, the second anti-oxidation protective layer 90 may also be a magnetic layer. In this way, during the welding process with the welding strip 210, the second anti-oxidation protective layer 90 can adsorb the welding strip 210, which can effectively prevent the welding strip 210 from being offset during the welding process, and improve the stability and reliability of welding. In other words, the second anti-oxidation protective layer 90 can effectively prevent the first metal plating layer 80 from being oxidized and can also position and pre-fix the welding strip 210 during the welding process.

[0129] Specifically, in such an embodiment, the magnetic layer refers to a film layer that has a magnetic adsorption function itself or a film layer that has a magnetic adsorption function after being powered on, and the magnetic layer can be made entirely of magnetic materials.

[0130] Of course, it can be understood that in some embodiments, the second anti-oxidation protective layer 90 may not be a magnetic layer made entirely of magnetic materials, but rather has a magnetic material component in the second anti-oxidation protective layer 90. 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 anti-oxidation protective layer can generate magnetic attraction to the welding strip 210.

[0131] In addition, some metal particles may splash out during the welding process. The magnetic attraction force can be used to adsorb some metal particles, thereby reducing the surface contamination of the battery cell, improving the light absorption capacity of the battery cell, and improving the light conversion efficiency of the battery cell.

[0132] See also Figure 6 In some embodiments, the second anti-oxidation protection layer 90 may not be provided on the first metal coating layer 80, but a second welding layer 92 may be provided. In this case, the second welding layer 92 is stacked on the first metal coating layer 80 and is used for welding with the welding strip 210. Figure 6 The second anti-oxidation protection layer 90 is replaced by a second welding layer 92.

[0133] In this way, the second welding layer 92 can ensure the welding performance with the welding strip, and at the same time can also protect the first metal plating layer 80.

[0134] In such an embodiment, the second welding layer 92 may include at least one of a tin layer, a nickel layer, a tin paste layer, an alloy layer including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel. In this way, it is possible to ensure excellent conductive properties while ensuring welding performance.

[0135] In some embodiments, only one continuous first opening 411 may be provided on the first portion 41 . In this case, the first conductive barrier structure includes only one first conductive barrier portion 51 disposed at the first opening 411 .

[0136] See also Figure 4-Figure 7 In some embodiments, on the first portion 41, the number of the first openings 411 may be multiple, and the multiple first openings 411 are arranged at intervals along the second direction. The number of the first conductive blocking portions 51 corresponds to the number of the first openings 411 one by one, and the first printing paste layer 60 is electrically connected to all the first conductive blocking portions 51.

[0137] In this way, a plurality of first openings 411 arranged at intervals are formed only on a partial area of ​​the first portion 41 and the first conductive barrier 51 is arranged only within the first opening 411. This can reduce the proportion of the area of ​​the metallized region on the first doping layer 20, reduce the recombination caused by metallization, and improve the efficiency of the back contact battery 100.

[0138] Specifically, in the embodiment of the present application, the first conductive barrier 51 may be located only in the first opening 411 (eg Figure 4-Figure 7 As shown), it may also be partially located in the first opening 411, and the other part extends to above the first portion 41 at the edge of the first opening 411, and the specific details are not limited here.

[0139] See also Figure 4-Figure 7 In some embodiments, when a plurality of spaced first openings 411 are provided on the first portion 41, each first conductive barrier 51 is independent of each other (ie, not in direct contact). In this way, the material used in the first conductive barrier structure can be reduced, thereby lowering the cost.

[0140] Specifically, in such a case, the first conductive barrier 51 may be located only in the first opening 411. Of course, in some embodiments, the first conductive barrier 51 may also partially protrude from the first opening 411 and extend to the first portion 41 at the edge of the first opening 411. In such a case, the first printing paste layer 60 surrounds the portion of the first conductive barrier 51 protruding from the first opening 411.

[0141] See also Figure 7In some embodiments, the first conductive barrier structure may further include a plurality of first conductive connection portions 52 , wherein the first conductive connection portions 52 connect two adjacent first conductive barrier portions 51 , and the first conductive connection portions 52 are disposed on the first portion 41 and are not in contact with the first doping layer 20 .

[0142] In this way, by providing the first conductive connecting portion 52 , a plurality of first conductive blocking portions 51 can be connected into a whole, thereby increasing the contact area between the first conductive blocking structure and the first printing paste layer 60 and improving the conductive performance.

[0143] In some embodiments, in the first conductive barrier structure, the length of the first conductive barrier portion 51 in the first opening 411 and in contact with the first doping layer 20 in the second direction is 5um-5000um, and the distance between two adjacent first openings 411 in the second direction is 10um-2000um.

[0144] In this way, it is possible to avoid the situation where the length of a single first conductive blocking portion 51 is too large, resulting in an excessively large metallization area and thus an excessively large composite and thus affecting efficiency; it is also possible to avoid the situation where the length of a single first conductive blocking portion 51 is too small, resulting in an excessively small contact area between the first printed paste layer 60 and thus easily resulting in unstable contact between the first printed paste layer 60.

[0145] At the same time, setting the spacing between two adjacent first openings 411 within the above reasonable range can also avoid the metallization area from being too large, and can also avoid the spacing between two adjacent first openings 411 being too large, which causes the carriers to be transmitted over a long distance during the collection process and causes excessive transmission losses. In other words, such a setting can control the metallization area within a reasonable range, avoid excessive metallization recombination losses, and avoid excessive carrier transmission losses, thereby balancing the relationship between recombination and transmission losses caused by metallization, so that the two achieve a better matching effect, thereby improving the electrical performance of the back contact battery 100.

[0146] Specifically, in such an embodiment, the length of the portion of the first conductive barrier 51 that is located in the first opening 411 and in contact with the first doping layer 20 in the second direction may be, for example, 5um, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, 400um, 500um, 1000um, 1500um, 2000um, 2500um, 3000um, 4000um, 5000um or any value between 5um-5000um.

[0147] The spacing between two adjacent first openings 411 in the second direction may be, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, 400um, 500um, 1000um, 1500um, 2000um or any value between 10um-2000um.

[0148] Furthermore, in some embodiments, in the first conductive barrier structure, the length of the first conductive barrier portion 51 located in the first opening 411 and in contact with the first doping layer 20 in the second direction may preferably be 10um-1000um, and the spacing between two adjacent first openings 411 in the second direction is 10um-1000um.

[0149] In this way, the recombination and transmission losses caused by metallization can be better matched, further improving the electrical performance of the back contact battery 100 .

[0150] Furthermore, in some embodiments, in the first conductive blocking structure, the length of the portion of the first conductive blocking portion 51 located in the first opening 411 and in contact with the first doping layer 20 in the second direction may be further preferably 10um-500um, and the spacing between two adjacent first openings 411 in the second direction is 10um-500um.

[0151] Specifically, in such an embodiment, in the first conductive barrier structure, the length of the portion of the first conductive barrier 51 located in the first opening 411 and in contact with the first doping layer 20 in the second direction may be further preferably 10um-100um, and the spacing between two adjacent first openings 411 in the second direction is 30um-500um. Most preferably, it is 10um-50um and 30um-300um.

[0152] That is to say, in the present application, in the first conductive blocking structure, the length of the first conductive blocking portion 51 located in the first opening 411 and in contact with the first doping layer 20 in the second direction is most preferably 10um-50um, and the spacing between two adjacent first openings 411 in the second direction is 30um-300um.

[0153] Specifically, through repeated research and demonstration by the inventors of the present application, by setting the above two values ​​within the most preferred range, the recombination and transmission losses brought by metallization can be optimally matched, and the performance of the back contact battery 100 can be optimized.

[0154] Specifically, in such an embodiment, the length of the portion of the first conductive barrier 51 located in the first opening 411 and in contact with the first doping layer 20 in the second direction may be, for example, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, or any value between 10um and 50um. The spacing between two adjacent first openings 411 in the second direction may be, for example, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, or any value between 30um and 300um.

[0155] In some embodiments, in a single first conductive barrier structure, the ratio of the sum of the contact areas of all the first conductive barriers 51 with the first doping layer 20 to the area of ​​the first doping layer 20 is greater than or equal to 0.0001 and less than 1. It should be noted that the area ratio here refers to the ratio of the sum of the contact areas of all the first conductive barriers 51 located on a single first doping layer 20 with the first doping layer 20 to the area of ​​the single first doping layer 20.

[0156] In this way, it is possible to avoid the metallization area on the first doping layer 20 being too small, which would lead to excessive carrier transmission losses, and it is also possible to avoid the metallization area being too large, which would lead to high metallization recombination and affect efficiency, thereby balancing the relationship between metallization recombination and carrier transmission losses and optimizing the performance of the back contact battery 100.

[0157] Furthermore, in such an embodiment, the area ratio between the two may preferably be 0.0001-0.5. In this way, the relationship between the balanced metallization recombination and the carrier transmission loss can be further optimized, so that the two can achieve a better matching effect.

[0158] In such an embodiment, the ratio between the two may be further preferably 0.0001-0.1, more preferably 0.0005-0.05, and most preferably 0.0005-0.02. That is to say, in the embodiment of the present application, 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 doping layer 20 and the area of ​​the first doping layer 20 is most preferably greater than or equal to 0.0005 and less than or equal to 0.02.

[0159] Specifically, through repeated research and demonstration by the inventors of this application, by setting the ratio of the above two within the most preferred range of 0.0005-0.02, the recombination and transmission losses brought by metallization can be optimally matched, and the performance and efficiency of the back contact battery 100 can be optimized.

[0160] See also Figure 8In some embodiments, the back passivation film layer 40 further includes a second portion 42 (i.e., a portion of the back passivation film layer 40 corresponding to the second doping layer 30) stacked on the second doping layer 30, and a second opening 421 is formed on the second portion 42. The back contact battery 100 further includes a second conductive barrier structure and a second printing paste layer 120. The second conductive barrier structure includes a second conductive barrier portion 111, which is at least partially disposed in the second opening 421 and in contact with the second doping layer 30. The second printing paste layer 120 is disposed on the second portion 42 and the second printing paste layer 120 is electrically connected to the second conductive barrier portion 111.

[0161] In this way, a second opening 421 is formed on the second portion 42 of the back passivation film layer 40 located on the second doping layer 30, a second conductive barrier 111 is provided at the second opening 421, a second printing paste layer 120 is provided on the second portion 42, and the second printing paste layer 120 is electrically connected to the second conductive barrier 111 to achieve current output. In this way, through the arrangement of the second conductive barrier 111 and the second printing paste layer 120, the blocking function of the second conductive barrier 111 can reduce the probability of deep energy level elements in the second printing paste layer 120 entering the second doping layer 30 and the silicon wafer 10, and even completely block the deep energy level elements, reduce the defects introduced by the deep energy level elements, and thus ensure the electrical performance of the back contact battery 100.

[0162] In the present application, it is preferred that the second opening 421 is provided on the second portions 42 on all the second doping layers 30, and the second conductive barrier 111 is located at the second opening 421. Of course, in some embodiments, the second opening 421 may be provided on the second portions 42 on some of the second doping layers 30, which is not specifically limited here. In the present application, the second conductive barrier structure may be provided on all the second portions 42, or only on some of the second portions 42, which is not specifically limited here.

[0163] It should be noted that, in the embodiment of the present application, the second printing paste layer 120 refers to a paste layer formed by screen printing using a paste, rather than a film layer formed by PVD coating or the like in the field of solar energy technology.

[0164] In some embodiments, the thickness of the second printing paste layer 120 is greater than the thickness of the second conductive barrier 111. In this way, the second printing paste layer 120 can realize the current convergence output, and the thickness of the second printing paste layer 120 is set to be greater than the thickness of the second conductive barrier 111, which can improve the lateral conductivity of the back contact battery 100, reduce transmission loss, and further improve the electrical performance and efficiency of the back contact battery 100. That is to say, in this embodiment, while improving the lateral conductivity to reduce transmission loss, the deep energy level elements in the second printing paste layer 120 can be effectively blocked from entering the second doping layer 30 and the silicon wafer 10, thereby further improving the performance of the back contact battery 100 and improving the efficiency of the back contact battery 100.

[0165] In some embodiments, a ratio between a thickness of the second printing paste layer 120 and a thickness of the second conductive barrier 111 is greater than 1 and less than or equal to 5,000.

[0166] In this way, by setting the thickness ratio of the two within this reasonable range, the cost can be controlled while ensuring the barrier performance of the second conductive barrier 111 and improving the lateral conductive performance. Specifically, in such an embodiment, the thickness ratio between the two can be, for example, 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.

[0167] Further, in such an embodiment, the ratio between the thickness of the second printing paste layer 120 and the thickness of the second conductive barrier 111 is preferably greater than 1 and less than or equal to 500. Thus, by setting the thickness ratio of the two within this preferred range, the barrier performance and the lateral conductive performance can be ensured while reducing the cost as much as possible.

[0168] Specifically, in such an embodiment, the thickness ratio between the two may be, for example, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 or other values ​​greater than 1 and less than 500, without limitation herein.

[0169] In some embodiments, the thickness of the second printing paste layer 120 is 5 um-50 um.

[0170] Thus, by setting the thickness of the second printing paste layer 120 within this reasonable range, it is possible to avoid the effect of improving the lateral conductivity performance being unable to achieve the expected effect due to its too low thickness, and to avoid the cost being too high due to its too thick thickness. In other words, such a setting can improve the lateral conductivity and reduce the transmission loss while controlling the cost.

[0171] Specifically, in such an embodiment, the thickness of the second printing paste layer 120 may be, for example, 5um, 6um, 7um, 8um, 9um, 10um, 15um, 20um, 25um, 35um, 40um, 45um, 50um or any value between 5um-50um.

[0172] In such an embodiment, the thickness of the second conductive barrier 111 follows the ratio rule described above, and preferably, the thickness ratio of the second printing paste layer 120 to the second conductive barrier 111 is greater than 1 and meets or is equal to 500.

[0173] In some embodiments, the thickness of the second conductive barrier 111 may be greater than or equal to 10 nm and less than 5 μm. In this way, it can be shown that the thickness of the second conductive barrier 111 is too small to fully block the deep energy level elements, resulting in poor blocking effect, and it can also avoid being too thick and causing high cost. In other words, such a setting can ensure the blocking effect while avoiding high cost.

[0174] Specifically, in such an embodiment, the thickness of the second conductive barrier 111 may be, for example, 10nm, 20nm, 30nm, 40nm, 50nm, 60nm, 70nm, 80nm, 90nm, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1um, 1.5um, 2um, 2.5um, 3um, 3.5um, 4um, 4.5um, 4.9um or any value greater than 10nm and less than 5um.

[0175] 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-coated copper paste printing layer, a nickel-coated copper paste printing layer, and a tin-coated copper paste printing layer.

[0176] Thus, the second printing paste layer 120 adopts such a printing paste layer, which can reduce the cost while ensuring the conductive performance of the second printing paste layer 120 .

[0177] Specifically, in such an embodiment, 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 screen printing or the like, and then the low-temperature paste is cured by drying or the like, and the second printing paste layer 120 only forms a conductive contact with the second conductive barrier 111, and does not burn through the second portion 42 of the back passivation film layer 40 to contact the second doping layer 30.

[0178] 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 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.

[0179] In this way, the second conductive barrier layer 51 can not only effectively block the deep energy level elements in the second printing paste layer 120, but also make it have better conductivity and improve the carrier collection efficiency. At the same time, it itself is not easy to cause a significant reduction in the minority carrier lifetime in the body region.

[0180] Specifically, in some embodiments, the second conductive barrier 111 may be made of a burn-through paste, for example, a burn-through silver paste, a burn-through aluminum paste, etc. In this case, the second opening 421 may be formed directly by burning through a partial area of ​​the second portion 42 during the process of forming the second conductive barrier 111.

[0181] Of course, in some embodiments, the second conductive barrier 111 can also be prepared by PVD or other methods. For example, in some embodiments, the second conductive barrier 111 can be a film layer such as a PVD silver layer or a PVD aluminum 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 is plated at the second openings 421 by PVD to form a plurality of isolated second conductive barrier 111, and then the isolated second conductive barrier 111 is electrically connected together by printing the second printing paste layer 120.

[0182] See also Fig. 9 In some embodiments, the back contact battery 100 may further include a third welding layer 130 , which is disposed on the second printing paste layer 120 , and the third welding layer 130 is used for welding with the welding ribbon 210 .

[0183] Thus, by further arranging a welding layer on the second printing paste layer 120 , it is possible to improve the stability during welding of the welding strip 210 , thereby preventing the second printing paste layer 120 from being directly welded and causing poor welding stability.

[0184] 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 including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel. In this way, the soldering performance with the soldering ribbon 210 can be improved while forming an excellent conductive contact with the second printing paste layer 120.

[0185] See also Fig. 9 In some embodiments, the back contact battery 100 may further include a third anti-oxidation protection layer 132, which is stacked on the second printing paste layer 120. The anti-oxidation capacity of the third anti-oxidation protection layer 132 is greater than that of the second printing paste layer 120. Fig. 9 The third welding layer 130 is replaced by a third anti-oxidation protection layer 132.

[0186] In this way, by setting the third anti-oxidation protection layer 132, the second printed paste layer 120 can be protected from oxidation, effectively preventing the second printed paste layer 120 from being exposed to the air for a long time during the transportation and storage of the back contact battery 100 to generate oxides, thereby causing the welding performance and the conductive performance to deteriorate.

[0187] In some embodiments, the third anti-oxidation protective layer 132 may be a layer structure with excellent anti-oxidation performance, for example, it may include at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer, or an inorganic film layer. The third anti-oxidation protective layer 132 may also be formed on the second printing paste layer 120 by PVD deposition, inkjet, etc.

[0188] In some embodiments, in such embodiments, the third anti-oxidation film layer 90 may also be used for welding with a welding ribbon, and the third anti-oxidation film layer 90 may be welded with the welding ribbon together with the second printing paste layer 120 .

[0189] See also Fig.10 In some other embodiments, the back contact battery 100 may further include a second metal plating layer 140 stacked on the second printing paste layer 120 .

[0190] Thus, by providing the second metal plating layer 140 on the second printing paste layer 120 , the conductive performance can be enhanced and the transmission loss can be reduced. Meanwhile, the second printing paste layer 120 can be protected and the reliability and weather resistance of the second printing paste layer 120 can be improved.

[0191] In such an embodiment, the second metal plating layer 140 may include at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

[0192] Thus, the above-mentioned type of metal coating is formed by electroplating or chemical plating, which can control the cost while ensuring the welding performance and conductive performance.

[0193] Please continue reading Fig.10 In some embodiments, the back contact battery 100 may further include a fourth anti-oxidation protection layer 150 stacked on the second metal plating layer 140. The fourth anti-oxidation protection layer 150 has an anti-oxidation capability greater than that of the second metal plating layer 140.

[0194] In this way, by providing the second metal coating 140, its welding performance with the welding strip 210 can be guaranteed, and the fourth anti-oxidation protection layer 150 can protect the second metal coating 140, effectively preventing the second metal coating 140 from being exposed to the air for a long time during the transportation and storage of the back contact battery 100 to generate oxides, thereby causing the welding performance and the conductive performance to deteriorate. At the same time, it can also effectively prevent the phenomenon of organic matter, dust and other impurities adhering to the surface, resulting in poor appearance and affecting efficiency.

[0195] In some embodiments, the second metal coating 140 may be preferably an electroplated copper layer, which has better welding performance, lower cost, and better electrical conductivity, thereby improving carrier collection efficiency.

[0196] Specifically, it can be understood that the second metal plating layer 140 plays a welding role and collects carriers through the second printing paste layer 120 and the second conductive barrier 111. It needs to be made of a relatively active metal, such as the electroplated copper layer mentioned above. However, the highly active metal plating layer is prone to oxidation, resulting in poor subsequent welding performance. Therefore, the present application can effectively avoid such a situation by providing a fourth anti-oxidation protective layer 150 on the first metal seed layer.

[0197] Specifically, in such an embodiment, the second metal plating layer 140 may be a metal electroplating layer with strong activity, such as an electroplated copper layer, and the fourth anti-oxidation protection layer 150 may be an inert metal layer. For example, in some embodiments, the fourth anti-oxidation protection layer 150 may include a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, and a metal oxide layer, which can be formed on the second metal plating layer 140 by PVD deposition, inkjet, etc.

[0198] Of course, in other embodiments, the fourth anti-oxidation protective layer 150 may also include an organic film layer or an inorganic film layer capable of resisting oxidation, such as an inorganic film layer having a chain structure, which is not specifically limited here, and is preferably an inert metal layer. That is to say, in the present application, the fourth anti-oxidation protective layer 150 may include at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer, or an inorganic film layer.

[0199] In some embodiments, the fourth anti-oxidation protective layer 150 may also be a magnetic layer. In this way, during the welding process with the welding strip 210, the fourth anti-oxidation protective layer 150 can adsorb the welding strip 210, which can effectively prevent the welding strip 210 from being offset during the welding process, and improve the stability and reliability of welding. In other words, the fourth anti-oxidation protective layer 150 can effectively prevent the second metal plating layer 140 from being oxidized and can also position and pre-fix the welding strip 210 during the welding process.

[0200] Specifically, in such an embodiment, the magnetic layer refers to a film layer that has a magnetic adsorption function itself or a film layer that has a magnetic adsorption function after being powered on, and the magnetic layer can be made entirely of magnetic materials.

[0201] Of course, it can be understood that in some embodiments, the fourth anti-oxidation protection layer 150 may not be a magnetic layer made entirely of magnetic materials, but rather has a magnetic material component in the fourth anti-oxidation protection layer 150. 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 anti-oxidation protection layer can generate magnetic attraction to the welding strip 210.

[0202] In addition, some metal particles may splash out during the welding process. The magnetic attraction force can be used to adsorb some metal particles, thereby reducing the surface contamination of the battery cell, improving the light absorption capacity of the battery cell, and improving the light conversion efficiency of the battery cell.

[0203] See also Fig.10 In some embodiments, the fourth anti-oxidation protection layer 150 may not be provided on the first metal coating layer 80, but a fourth welding layer 152 may be provided. In this case, the fourth welding layer 152 is stacked on the second metal coating layer 140 and is used for welding with the welding strip 210. Fig.10 The fourth anti-oxidation protection layer 150 is replaced by a fourth welding layer 152.

[0204] In this way, the fourth welding layer 152 can ensure the welding performance with the welding strip, and at the same time, the second metal plating layer 140 can be protected.

[0205] In such an embodiment, the fourth welding layer 152 may include at least one of a tin layer, a nickel layer, a tin paste layer, an alloy layer including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel. In this way, it can have excellent conductive properties while ensuring welding performance.

[0206] In some embodiments, only one continuous second opening 421 may be provided on the second portion 42 . In this case, the second conductive barrier structure includes only one second conductive barrier portion 111 disposed at the second opening 421 .

[0207] See also Figure 8-Figure 10 In some embodiments, on the second portion 42, the number of the second openings 421 may be multiple, and the multiple second openings 421 are arranged at intervals along the second direction. The number of second conductive blocking portions corresponds to the number of second openings 421 one by one, and the second printing paste layer 120 is electrically connected to all second conductive blocking portions 111.

[0208] In this way, a plurality of second openings 421 arranged at intervals are formed only on a partial area of ​​the second portion 42 and the second conductive barrier 111 is arranged only within the second openings 421. This can reduce the proportion of the area of ​​the metallized region on the second doping layer 30, reduce the recombination caused by the metallization, and improve the efficiency of the back contact battery 100.

[0209] Specifically, in the embodiment of the present application, the second conductive barrier 111 may be located only in the second opening 421 (eg Figure 8-Figure 10 As shown), it may also be partially located in the second opening 421, and the other part extends to above the second portion 42 at the edge of the second opening 421, and the specific details are not limited here.

[0210] See also Figure 8-Figure 10 In some embodiments, when a plurality of spaced second openings 421 are provided on the first portion 41, each second conductive barrier 111 is independent of each other (ie, not in direct contact). In this way, the material used in the second conductive barrier structure can be reduced, thereby reducing costs.

[0211] Specifically, in such a case, the second conductive barrier 111 may be located only in the second opening 421. Of course, in some embodiments, the second conductive barrier 111 may also be partially protruding from the second opening 421 and extending to the second portion 42 at the edge of the second opening 421. In such a case, the second printing paste layer 120 surrounds the portion of the second conductive barrier 111 protruding from the second opening 421.

[0212] See also Fig.11In some embodiments, the second conductive barrier structure may further include a plurality of second conductive connection portions 112 , wherein the second conductive connection portions 112 connect two adjacent second conductive barrier portions 111 , and the second conductive connection portions 112 are disposed on the second portion 42 and are not in contact with the second doping layer 30 .

[0213] In this way, the second conductive connecting portion 112 can be provided to connect a plurality of second conductive blocking portions 111 into a whole, thereby increasing the contact area between the second conductive blocking structure and the second printing paste layer 120 and improving the conductive performance.

[0214] In some embodiments, in the second conductive barrier structure, the length of the second conductive barrier portion 111 in the second opening 421 and in contact with the second doping layer 30 in the second direction is 5um-5000um, and the distance between two adjacent second openings 421 in the second direction is 10um-2000um.

[0215] In this way, it is possible to avoid the situation where the length of a single second conductive blocking portion 111 is too large, resulting in an excessively large metallization area and thus an excessively large composite and thus affecting efficiency; it is also possible to avoid the situation where the length of a single second conductive blocking portion 111 is too small, resulting in an excessively small contact area between the second printed paste layer 120 and thus easily resulting in unstable contact between the second printed paste layer 120.

[0216] At the same time, setting the spacing between two adjacent first openings within the above reasonable range can also avoid the metallization area from being too large, and can also avoid the spacing between two adjacent second openings 421 being too large, which causes the carriers to be transmitted over a long distance during the collection process and causes excessive transmission losses. In other words, such a setting can control the metallization area within a reasonable range, avoid excessive metallization recombination losses, and avoid the transmission loss process of carriers, thereby balancing the relationship between the recombination and transmission losses caused by metallization, so that the two achieve a better matching effect, thereby improving the electrical performance of the back contact battery 100.

[0217] Specifically, in such an embodiment, the length of the portion of the second conductive barrier 111 that is located in the second opening 421 and in contact with the second doping layer 30 in the second direction may be, for example, 5um, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, 400um, 500um, 1000um, 1500um, 2000um, 2500um, 3000um, 4000um, 5000um or any value between 5um-5000um.

[0218] The spacing between two adjacent second openings 421 in the second direction may be, for example, 10um, 20um, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, 400um, 500um, 1000um, 1500um, 2000um or any value between 10um-2000um.

[0219] Furthermore, in some embodiments, in the second conductive barrier structure, the length of the second conductive barrier portion 111 located in the second opening 421 and in contact with the second doping layer 30 in the second direction may preferably be 10um-1000um, and the spacing between two adjacent second openings 421 in the second direction is 10um-1000um.

[0220] In this way, the recombination and transmission losses caused by metallization can be better matched, further improving the electrical performance of the back contact battery 100 .

[0221] Furthermore, in some embodiments, in the second conductive blocking structure, the length of the portion of the second conductive blocking portion 111 located in the second opening 421 and in contact with the second doping layer 30 in the second direction may be further preferably 10um-500um, and the spacing between two adjacent second openings 421 in the second direction is 10um-500um.

[0222] Specifically, in such an embodiment, in the second conductive barrier structure, the length of the portion of the second conductive barrier 111 located in the second opening 421 and in contact with the second doping layer 30 in the second direction may be further preferably 10um-100um, and the spacing between two adjacent second openings 421 in the second direction is 30um-500um. Most preferably, it is 10um-50um and 30um-300um.

[0223] That is to say, in the present application, in the second conductive blocking structure, the length of the portion of the second conductive blocking portion 111 located in the second opening 421 and in contact with the second doping layer 30 in the second direction is most preferably 10um-50um, and the spacing between two adjacent second openings 421 in the second direction is 30um-300um.

[0224] Specifically, through repeated research and demonstration by the inventors of the present application, by setting the above two values ​​within the most preferred range, the recombination and transmission losses brought by metallization can be optimally matched, and the performance of the back contact battery 100 can be optimized.

[0225] Specifically, in such an embodiment, the length of the portion of the second conductive barrier 111 located in the second opening 421 and in contact with the second doping layer in the second direction may be, for example, 10um, 15um, 20um, 25um, 30um, 35um, 40um, 45um, 50um, or any value between 10um and 50um. The spacing between two adjacent second openings 421 in the second direction may be, for example, 30um, 40um, 50um, 60um, 70um, 80um, 90um, 100um, 200um, 300um, or any value between 30um and 300um.

[0226] In some embodiments, in a single second conductive barrier structure, the ratio of the sum of the contact areas of all the second conductive barriers with the second doped layer to the area of ​​the second doped layer is greater than or equal to 0.0001 and less than 1. It should be noted that the area ratio here refers to the ratio of the sum of the contact areas of all the second conductive barriers 111 located on a single second doped layer 30 with the second doped layer 30 to the area of ​​the single second doped layer 30 .

[0227] In this way, it is possible to avoid the metallization area on the second doping layer 30 being too small, which would lead to excessive carrier transmission loss, and it is also possible to avoid the metallization area being too large, which would lead to high metallization recombination and affect efficiency, thereby balancing the relationship between metallization recombination and carrier transmission loss and optimizing the performance of the back contact battery 100.

[0228] Furthermore, in such an embodiment, the area ratio between the two may preferably be 0.0001-0.5. In this way, the relationship between the balanced metallization recombination and the carrier transmission loss can be further optimized, so that the two can achieve a better matching effect.

[0229] In such an embodiment, the ratio between the two may be further preferably 0.0001-0.1, more preferably 0.0005-0.05, and most preferably 0.0005-0.02. That is to say, in the embodiment of the present application, 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 doping layer 30 and the area of ​​the second doping layer 30 is most preferably greater than or equal to 0.0005 and less than or equal to 0.02.

[0230] Specifically, through repeated research and demonstration by the inventors of this application, by setting the ratio of the above two within the most preferred range of 0.0005-0.02, the recombination and transmission losses brought by metallization can be optimally matched, and the performance and efficiency of the back contact battery 100 can be optimized.

[0231] See also Fig.12In some embodiments, in the battery assembly 200, a plurality of welding strips 210 for connecting the back contact batteries 100 in series may be arranged at intervals along the second direction and cross-arranged with all the first doping layers 20 and the second doping layers 30. Among two adjacent welding strips 210, one welding strip 210 is conductively connected to all the first printing paste layers 60 and insulated from the second printing paste layer 120 (when the back contact battery 100 has the first welding layer 70 or the second welding layer 92 mentioned above, it may be welded to the first welding layer 70 or the second welding layer 92). When the back contact battery 100 has the first metal coating layer 80 described above, it can be welded to the first metal coating layer 80), and another welding strip 210 is conductively connected to all the second printing paste layers 120 and is insulated from the first printing paste layer 60 (when the back contact battery 100 has the third welding layer 130 or the fourth welding layer 152 described above, it can be welded to the third welding layer 130 or the fourth welding layer 152, and when the back contact battery 100 has the second metal coating layer 140 described above, it can be welded to the second metal coating layer 140).

[0232] See also Fig.11 In some other embodiments, in the battery assembly 200, each first printing paste layer 60 may be provided with a welding strip 210, which can be welded to the first welding layer 70 or the second welding layer 92 when the back contact battery 100 has the first welding layer 70 or the second welding layer 92, and can be welded to the first metal plating layer 80 when the back contact battery 100 has the first metal plating layer 80 described above. Each second metallization layer is also provided with a welding strip 210, which can be welded to the second welding layer 92130 when the back contact battery 100 has the second welding layer 92130 described above, and can be welded to the second metal plating layer 140 when the back contact battery 100 has the second metal plating layer 140 described above.

[0233] In the description of this specification, the description with reference to the terms "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiments or examples are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0234] In addition, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A back contact battery, characterized in that: include: A silicon wafer having a front side and a back side facing each other; a first doping layer and a second doping layer, wherein the first doping layer and the second doping layer are arranged on the back surface along a first direction and are spaced apart and extend along a second direction, the second direction intersects the first direction, and the first doping layer and the second doping layer have opposite doping types; a back passivation film layer, the back passivation film layer being stacked on at least the first doping layer and the second doping layer, the back passivation film layer comprising a first portion stacked on the first doping layer, and a first opening being formed on at least one of the first portions; at least one first conductive barrier structure, the first conductive barrier structure comprising 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 provided on the first portion and is electrically connected to the first conductive barrier, wherein a thickness of the first printing paste layer is greater than a thickness of the first conductive barrier.

2. The back contact cell according to claim 1, characterized in that: A ratio between a thickness of the first printing paste layer and a thickness of the first conductive barrier portion is greater than 1 and less than or equal to 5,000.

3. The back contact battery according to claim 2, characterized in that: A ratio between a thickness of the first printing paste layer and a thickness of the first conductive barrier portion is greater than 1 and less than or equal to 500.

4. The back contact cell according to claim 1, characterized in that: The back contact battery further includes a first anti-oxidation protection layer, which is stacked on the first printing paste layer.

5. The back contact cell according to claim 4, characterized in that: The first anti-oxidation protective layer includes at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer or an inorganic film layer.

6. The back contact cell according to claim 1, characterized in that: The back contact battery further includes a first welding layer, which is stacked on the first printing paste layer and is used for welding with a welding ribbon.

7. The back contact cell according to claim 6, characterized in that: The first soldering layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel.

8. The back contact cell according to claim 1, characterized in that: The back contact battery further includes a first metal plating layer stacked on the first printing paste layer.

9. The back contact battery according to claim 8, characterized in that The first metal plating layer includes at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

10. The back contact cell according to claim 8, characterized in that The back contact battery further includes a second anti-oxidation protection layer or a second welding layer stacked on the first metal plating layer.

11. The back contact cell according to claim 10, characterized in that The second anti-oxidation layer protection includes at least one of a tin layer, a nickel layer, an alloy layer comprising tin and copper, an alloy layer comprising tin and nickel, an alloy layer comprising tin and silver, an alloy layer comprising tin and bismuth, a metal oxide layer, an organic film layer or an inorganic film layer.

12. The back contact cell according to claim 10, characterized in that: The second solder layer includes at least one of a tin layer, a nickel layer, a solder paste layer, an alloy layer including tin and silver, an alloy layer including tin and bismuth, an alloy layer including tin and copper, and an alloy layer including tin and nickel.

13. The back contact cell according to claim 1, characterized in that: 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 cell according to claim 1, characterized in that The first printing paste layer includes at least one of a copper paste printing layer, an aluminum paste printing layer, a copper-aluminum paste printing layer, a silver-coated copper paste printing layer, a nickel-coated copper paste printing layer, and a tin-coated copper paste printing layer.

15. The back contact cell according to claim 1, characterized in that On the first part, there are multiple first openings, the multiple first openings are arranged at intervals along the second direction, the number of the first conductive blocking parts corresponds to the number of the first openings, and the first printing paste layer is electrically connected to all the first conductive blocking parts.

16. The back contact cell according to claim 15, characterized in that Each of the first conductive barrier parts is independent of each other; or, the first conductive barrier structure further includes a plurality of first conductive connecting parts, the first conductive connecting parts connecting two adjacent first conductive barrier parts, and the first conductive connecting parts are arranged on the first portion and are not in contact with the first doping layer.

17. The back contact cell according to claim 15, characterized in that: In the first conductive barrier structure, the length of the first conductive barrier portion located in the first opening and in contact with the first doping layer in the second direction is 5um-5000um, and the distance between two adjacent first openings in the second direction is 10um-2000um.

18. The back contact cell according to claim 17, characterized in that In the first conductive barrier structure, the length of the first conductive barrier portion located in the first opening and in contact with the first doping layer in the second direction is 10um-500um, and the distance between two adjacent first openings in the second direction is 10um-500um.

19. The back contact cell according to claim 18, characterized in that In the first conductive barrier structure, the length of the first conductive barrier portion located in the first opening and in contact with the first doping layer in the second direction is 10um-50um, and the distance between two adjacent first openings in the second direction is 30um-300um.

20. The back contact cell according to claim 15, characterized in that In a single first conductive barrier structure, a ratio of a sum of contact areas of all the first conductive barrier portions with the first doping layer to an area of ​​the first doping layer is greater than or equal to 0.0001 and less than 1.

21. The back contact cell according to claim 20, characterized in that In a single first conductive barrier structure, a ratio between a sum of contact areas of all the first conductive barrier portions with the first doping layer and an area of ​​the first doping layer is 0.0001-0.

1.

22. The back contact cell according to claim 21, characterized in that In a single first conductive barrier structure, a ratio between a sum of contact areas of all the first conductive barrier portions with the first doping layer and an area of ​​the first doping layer is 0.0005-0.

02.

23. The back contact cell according to claim 1, characterized in that The thickness of the first printing paste layer is 5um-50um; and / or The thickness of the first conductive barrier portion is greater than or equal to 10 nm and less than 5 um.

24. The back contact cell according to any one of claims 1 to 23, characterized in that: The back passivation film layer further includes a second portion stacked on the second doping layer, and a second opening is formed on at least one of the second portions; The back contact battery further comprises: at least one second conductive barrier structure, the second conductive barrier structure comprising 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 of the second conductive barrier portions.

25. The back contact cell according to claim 24, characterized in that The thickness of the second printing paste layer is greater than the thickness of the second conductive barrier.

26. The back contact cell according to claim 25, characterized in that A ratio between a thickness of the second printing paste layer and a thickness of the second conductive barrier portion is greater than 1 and less than 5,000.

27. The back contact cell according to claim 26, characterized in that A ratio between a thickness of the second printing paste layer and a thickness of the second conductive barrier portion is greater than 1 and less than 500.

28. The back contact cell according to claim 24, characterized in that The back contact battery further includes a third anti-oxidation protection layer, and the third anti-oxidation protection layer is stacked on the second printing paste layer.

29. The back contact cell according to claim 24, characterized in that The back contact battery further includes a third welding layer, which is stacked on the second printing paste layer and is used for welding with a welding ribbon.

30. The back contact cell according to claim 24, characterized in that The back contact battery further includes a second metal plating layer stacked on the second printing paste layer.

31. The back contact cell according to claim 30, characterized in that The second metal plating layer includes at least one of an electroplated copper layer, an electroplated nickel layer, an electroplated copper-tin alloy layer, an electroplated copper-silver alloy layer, a chemically plated copper layer or a chemically plated nickel layer, a chemically plated copper-tin alloy layer, and a chemically plated copper-silver alloy layer.

32. The back contact cell according to claim 30, characterized in that The back contact battery further includes a fourth anti-oxidation protection layer or a fourth welding layer stacked on the second metal plating layer.

33. The back contact cell according to claim 24, characterized in that On the second part, there are multiple second openings, the multiple second openings are arranged at intervals along the second direction, the number of the second conductive blocking parts corresponds to the number of the second openings, and the second printing paste layer is electrically connected to all the second conductive blocking parts.

34. The back contact cell according to claim 33, characterized in that Each of the second conductive barrier portions is independent of each other; or, the second conductive barrier structure further includes a plurality of second conductive connecting portions, the second conductive connecting portions connecting two adjacent second conductive barrier portions, and the second conductive barrier portions are arranged on the second portion and are not in contact with the second doped layer.

35. The back contact cell according to claim 33, characterized in that In the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 5um-5000um, and the distance between two adjacent second openings in the second direction is 10um-2000um.

36. The back contact cell according to claim 35, characterized in that In the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 10um-500um, and the distance between two adjacent second openings in the second direction is 10um-500um.

37. The back contact cell according to claim 36, characterized in that In the second conductive barrier structure, the length of the second conductive barrier portion located in the second opening and in contact with the second doping layer in the second direction is 10um-50um, and the distance between two adjacent second openings in the second direction is 30um-300um.

38. The back contact cell according to claim 24, characterized in that In a single second conductive barrier structure, a ratio of a sum of contact areas of all the second conductive barrier portions with the second doping layer to an area of ​​the second doping layer is greater than or equal to 0.0001 and less than 1.

39. The back contact cell according to claim 38, characterized in that In a single second conductive barrier structure, a ratio between a sum of contact areas of all the second conductive barrier portions with the second doping layer and an area of ​​the second doping layer is 0.0001-0.

1.

40. The back contact cell according to claim 39, characterized in that In a single second conductive barrier structure, a ratio between a sum of contact areas of all the second conductive barrier portions with the second doping layer and an area of ​​the second doping layer is 0.0005-0.

02.

41. The back contact cell according to claim 24, characterized in that The thickness of the second printing paste layer is 5um-50um; and / or The thickness of the second conductive barrier portion is greater than or equal to 10 nm and less than 5 um.

42. A battery assembly, characterized in that: A back contact battery comprising any one of several claims 1-41.

43. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 42.

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