Main-grid-free back contact battery, battery assembly and photovoltaic system

Abstract

The utility model is suitable for the technical field of solar cells, and provides a main-grid-free back contact cell, a cell assembly and a photovoltaic system, and a silicon substrate of the main-grid-free back contact cell is provided with a first test contact structure and a second test contact structure which are used for being in contact with probes with different polarities of a test device. The first test contact structure is conductively connected with all the first fine grids, and the second test contact structure is conductively connected with all the second fine grids. Thus, through the arrangement of the first test contact structure and the second test contact structure, the area of the first test contact structure and the area of the second test contact structure are larger than those of a single first fine grid and a single second fine grid, and when electrical performance testing, EL testing, hot spot testing and the like are carried out on the main-grid-free back contact battery, the testing efficiency is improved. The positive and negative probes of the testing device can be in stable contact with the first testing contact structure and the second testing contact structure respectively, so that the testing difficulty is reduced, and the testing reliability and stability are improved.

Description

Technical Field

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

[0002] In the related art, in a busbar-less back-contact solar cell, a busbar-less design is adopted on the back side. Due to the busbar-less design on the back side, when the battery is subjected to electrical performance tests (such as IV testing) and hot spot performance tests, it is difficult for the test probe to form a stable electrical contact with the battery, resulting in greater testing difficulty and poor test reliability and stability. Utility Model Content

[0003] The present application provides a busbar-free back-contact battery, battery assembly and photovoltaic system, aiming to solve the technical problem in the prior art that the probe cannot form stable contact when testing the busbar-free back-contact battery, resulting in poor test reliability and stability.

[0004] The present application is implemented as follows: a busbar-less back-contact battery according to an embodiment of the present application comprises:

[0005] a silicon substrate having opposite front and back surfaces;

[0006] A plurality of first fine grids and a plurality of second fine grids are provided on the back surface, wherein the plurality of first fine grids and the plurality of second fine grids are alternately arranged in sequence along a first direction and extend along a second direction, wherein the second direction intersects the first direction; and

[0007] a first test contact structure and a second test contact structure disposed on the back surface;

[0008] Among them, the first test contact structure is conductively connected to all the first fine gates and crosses with several second fine gates, the second fine gates that cross the first test contact structure are disconnected at the first test contact structure, the second test contact structure is conductively connected to all the second fine gates and crosses with several first fine gates, the first fine gates that cross the second test contact structure are disconnected at the second test contact structure, and the first test contact structure and the second test contact structure are respectively used to contact probes of different polarities in the test device.

[0009] The present application also provides a battery assembly, which includes several busbar-free back-contact batteries as described in any one of the above items.

[0010] The present application also provides a photovoltaic system, which includes the above-mentioned battery assembly.

[0011] In the busbar-free back-contact cell, cell assembly, and photovoltaic system of the embodiments of the present application, a first test contact structure and a second test contact structure for contacting probes of different polarities of a test device are provided on the silicon substrate, and the first test contact structure is conductively connected to all first fine grids, and the second test contact structure is conductively connected to all second fine grids. In this way, by providing the first test contact structure and the second test contact structure, the first test contact structure and the second test contact structure have a larger area than a single first fine grid and a single second fine grid. When performing electrical performance tests (such as IV testing), EL testing, and hot spot testing on the busbar-free back-contact cell, the positive and negative probes of the test device can form stable contact with the first test contact structure and the second test contact structure, respectively, thereby reducing the difficulty of testing and improving the reliability and stability of testing.

[0012] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a module schematic diagram of a photovoltaic system provided by an embodiment of the present application;

[0014] Figure 2 Schematic diagram of a module of a battery assembly provided in an embodiment of the present application;

[0015] Figure 3 Schematic diagram of the planar structure of a busbar-free back contact battery provided in an embodiment of the present application;

[0016] Figure 4 yes Figure 3 An enlarged schematic diagram of the busbar-free back contact cell at IV;

[0017] Figure 5 yes Figure 3 Another partial enlarged schematic diagram of the busbar-less back contact cell at V;

[0018] Figure 6 1 is another schematic planar structural diagram of a busbar-free back contact battery provided in an embodiment of the present application;

[0019] Figure 7 yes Figure 6 An enlarged schematic diagram of the busbar-free back contact cell at position VII;

[0020] Figure 8 yes Figure 6 An enlarged schematic diagram of the busbar-free back contact cell at position VIII;

[0021] Figure 9 1 is another schematic planar structural diagram of a busbar-less back contact battery provided in an embodiment of the present application;

[0022] Figure 10 1 is another schematic planar structural diagram of a busbar-less back contact battery provided in an embodiment of the present application;

[0023] Figure 11 yes Figure 9 A magnified schematic diagram of the busbar-free back contact cell at position XI;

[0024] Figure 12 yes Figure 9 Another enlarged schematic diagram of the busbar-less back contact cell at position XI;

[0025] Figure 13 yes Figure 10 An enlarged schematic diagram of the busbar-free back contact cell at position XIII;

[0026] Figure 14 yes Figure 10 Another enlarged schematic diagram of the busbar-less back contact cell at position XIII;

[0027] Figure 15 1 is another schematic planar structural diagram of a busbar-less back contact battery provided in an embodiment of the present application;

[0028] Figure 16 1 is another schematic planar structural diagram of a busbar-less back contact battery provided in an embodiment of the present application;

[0029] Figure 17 This is another schematic planar structural diagram of a busbar-less back contact battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions, and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and examples. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. In addition, it should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0031] In the description of this application, it should be understood that the terms "length", "width", "up", "down", "top", "bottom", "horizontal", "longitudinal", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, "several", "plurality" and "multiple roots" mean two (roots) or more (roots), unless otherwise clearly specified.

[0033] In the description of this application, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections, electrical connections, or mutual communication; they can refer to direct connections or indirect connections through an intermediate medium; they can refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0034] In this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0035] The disclosure below provides many different embodiments or examples for realizing different structures of the present application. In order to simplify the disclosure of the present application, the components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present application. In addition, the present application may repeat reference numbers and / or reference letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present application provides examples of various specific processes and materials, but those skilled in the art will appreciate the application of other processes and / or the use scenarios of other materials.

[0036] See also Figure 1-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, the battery assembly 200 in the embodiment of the present application may include several battery strings, and the battery string may include several main-grid-free back-contact batteries 100 in the embodiment of the present application.

[0037] In the present application, multiple busbar-less back-contact cells 100 in a battery assembly 200 can be serially connected via welding ribbons to form a battery string. The battery strings in the battery assembly 200 can be connected in series, in parallel, or in a combination of series and parallel to achieve current convergence output. For example, busbars can be used to connect the battery strings.

[0038] See also Figure 3 The busbar-less back-contact cell 100 in the embodiment of the present application may include a silicon substrate 10 , a plurality of first fine gates 20 , a plurality of second fine gates 30 , a first test contact structure 40 , and a second test contact structure 50 .

[0039] The silicon substrate 10 has a front side and a back side 11 opposite to each other. A plurality of first fine gates 20 and a plurality of second fine gates 30 are arranged on the back side 11 of the silicon substrate 10. The plurality of first fine gates 20 and the plurality of second fine gates 30 are alternately arranged in sequence along a first direction. In addition, the first fine gates 20 and the second fine gates 30 both extend along a second direction, which intersects the first direction.

[0040] Specifically, if Figure 3 As shown, the first direction and the second direction may be the longitudinal direction and the lateral direction of the busbarless back contact solar cell 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, the first direction and the second direction may be the diagonal direction of the silicon substrate 10, respectively, and the specific embodiment is not limited here.

[0041] Please continue reading Figure 3 The first test contact structure 40 and the second test contact structure 50 are also both arranged on the back side 11 .

[0042] The first test contact structure 40 is conductively connected to all the first fine gates 20 and crosses some second fine gates 30 . The second fine gates 30 crossing the first test contact structure 40 are disconnected at the first test contact structure 40 .

[0043] The second test contact structure 50 is conductively connected to all the second fine gates 30 and crosses some of the first fine gates 20 . The first fine gates 20 crossing the second test contact structure 50 are disconnected at the second test contact structure 50 .

[0044] The first test contact structure 40 and the second test contact structure 50 are respectively used to contact probes of different polarities in the test device. For example, the first test contact structure 40 can contact a first probe, and the second test contact structure 50 can contact a second probe, where one of the first probe and the second probe is a positive probe and the other is a negative probe.

[0045] It should be noted that, in the present application, “the first test contact structure 40 is conductively connected to all the first fine grids 20” means that when in contact with the probe of the test device, all the first fine grids 20 can be conductively connected to the probe of the test device through the first test contact structure 40. The setting method can be that all the first fine grids 20 are directly connected to the first test contact structure 40 to form a whole or are connected to form a whole through other connection structures (such as the first bus electrode 60 below) and then conductively connected to the probe through the first test contact structure 40. Alternatively, the first test contact structure 40 can include multiple parts (such as multiple first test parts 41 below), and each first test part 41 is conductively connected to part of the first fine grids 20. During the test process, the probe on each first test part 41 is used to conductively connect them, so that all the first fine grids 20 can be conductively connected to the probe of the test device during the test.

[0046] Similarly, "the second test contact structure 50 is conductively connected to all second fine grids 30" means that when contacted by a probe of a test device, all second fine grids 30 can be conductively connected to the probe of the test device through the second test contact structure 50. The arrangement can be such that all second fine grids 30 are directly connected to the second test contact structure 50 to form a whole, or connected to form a whole through other connection structures (such as the second bus electrode 70 described below) and then conductively connected to the probe through the second test contact structure 50. Alternatively, the second test contact structure 50 can include multiple parts (such as multiple second test parts 51 described below), each second test part 51 correspondingly conductively connected to a portion of the second fine grids 30. During the test process, the probe on each second test part 51 is used to conductively connect them, so that all second fine grids 30 can be conductively connected to the probe of the test device during testing. The test device can be an IV test device, an EL test device, or other equipment.

[0047] In addition, in the present application, the intersection of the fine gate and other structural components (such as the test contact structure mentioned above, the test part mentioned below, etc.) can be understood as the fine gate directly crossing and connecting with other structures in the second direction and having an intersection, or the extension line of the fine gate in the second direction crossing with other structures and having an intersection.

[0048] Furthermore, in the present application, the fine gate crossing the test contact structure being disconnected at the test contact structure means that the fine gate is discontinuous at the test contact structure, or the fine gate crossing the test contact structure only extends to one side of the test contact structure.

[0049] In the busbar-less back-contact cell 100, cell assembly 200, and photovoltaic system 1000 of the embodiments of the present application, a first test contact structure 40 and a second test contact structure 50 for contacting probes of different polarities of a test device are provided on the silicon substrate 10. The first test contact structure 40 is conductively connected to all first fine grids 20, and the second test contact structure 50 is conductively connected to all second fine grids 30. Thus, by providing the first test contact structure 40 and the second test contact structure 50, the first test contact structure 40 and the second test contact structure 50 have a larger area than a single first fine grid 20 and a single second fine grid 30. When the busbar-less back-contact cell 100 is subjected to electrical performance tests (e.g., IV tests), EL tests, and hot spot tests, the positive and negative probes of the test device can form stable contacts with the first test contact structure 40 and the second test contact structure 50, respectively, thereby reducing the difficulty of testing and improving test reliability and stability.

[0050] Specifically, it is understood that in the present application, the back side 11 of the silicon substrate 10 has a plurality of first doped layers (not shown) and second doped layers (not shown), which are P-type doped layers and N-type doped layers, respectively. A back passivation layer (not shown) is provided on the first doped layers and the second doped layers. The first fine gate 20 is correspondingly disposed above the first doped layers and penetrates the back passivation layer to form an ohmic contact with the first doped layers. The second fine gate 30 is correspondingly disposed on the second doped layers and penetrates the back passivation layer to form an ohmic contact with the second doped layers. That is, the first fine gate 20 and the second fine gate 30 have opposite polarities, with one being a positive fine gate and the other being a negative fine gate.

[0051] Taking IV testing as an example, when performing IV testing on the main-grid-free back-contact battery 100 of the present application, the positive probe and the negative probe of the testing device can be formed into stable contact with the first test contact structure 40 and the second test contact structure 50 respectively, thereby obtaining IV test data of the main-grid-free back-contact battery 100.

[0052] Taking the hot spot test as an example, when performing a hot spot test on the busbar-less back contact battery 100 of the present application, the positive probe and the negative probe of the test device can be formed into stable contact with the first test contact structure 40 and the second test contact structure 50 respectively, and then the scene of the busbar-less back contact battery 100 being blocked is simulated to observe the temperature of various parts of the busbar-less back contact battery 100.

[0053] Please continue reading Figure 3 In some embodiments, the first test contact structure 40 may include a plurality of first test portions 41 spaced apart from each other, each first test portion 41 correspondingly intersecting a plurality of first fine gates 20 and a plurality of second fine gates 30 , and the second fine gates 30 intersecting the first test portion 41 are disconnected at the first test portion 41 ;

[0054] The second test contact structure 50 includes a plurality of second test portions 51 spaced apart from each other. Each first test portion 41 intersects with a plurality of first fine gates 20 and a plurality of second fine gates 30 . A first fine gate 20 intersecting a second test portion 51 is disconnected at the second test portion 51 .

[0055] Thus, during testing, each first test portion 41 and each second test portion 51 can be contacted by one or more test probes, thereby achieving electrical continuity between all first fine gates 20 and one polarity of the test device, and between all second fine gates 30 and the other polarity of the test device. Furthermore, by configuring the first test contact structure 40 to include a plurality of spaced first test portions 41 and configuring the second test contact structure 50 to include a plurality of spaced second test portions 51, multiple shorter transmission paths can be used during testing, reducing losses and improving test accuracy.

[0056] Specifically, in such an embodiment, each first test part 41 and each second test part 51 can correspond to contact with a probe, and the testing device has a probe row. During the test process, the probe on the probe row with the same polarity as the first test part 41 contacts and is connected to the first test part 41, and the probe on the probe row with the same polarity as the second test part 51 contacts and is connected to the second test part 51, and the probes with the same polarity on the probe row are conductive together.

[0057] In some embodiments, the area of ​​a single first test portion 41 and a single second test portion 51 may be 1.5 mm 2 -20mm 2 .

[0058] In this way, setting the areas of the first test section 41 and the second test section 51 within this reasonable range can avoid the first test section 41 and the second test section 51 from being too small, which results in the first test section 41 and the second test section 51 being unable to form stable contact with the test probe; and can also avoid the first test section 41 and the second test section 51 from being too large, which results in a small area on the back side 1111 where no metal fine grid is set, thereby affecting the current collection efficiency.

[0059] Specifically, in such an embodiment, the area of ​​the first test portion 41 and the second test portion 51 may be, for example, 1.5 mm 2 , 2mm 2 , 2.5mm 2 , 2.78mm 2 , 3mm 2 , 3.5mm 2 , 4mm 2 , 4.5mm 2 , 5mm 2 , 5.5mm2 , 6mm 2 , 6.5mm 2 , 7.5mm 2 , 8mm 2 , 8.5mm 2 , 9mm 2 , 9.5mm 2 , 10mm 2 , 11mm 2 , 12mm 2 , 13mm 2 , 14mm 2 , 15mm 2 , 16mm 2 , 17mm 2 , 18mm 2 , 19mm 2 , 20mm 2 or 1.5mm 2 -20mm 2 Any value between , not limited here.

[0060] It should be noted that in the embodiment of the present application, the first test portion 41 and the second test portion 51 may be filled with physical points of welding material or metal material, or may be a mesh structure composed of multiple metal wires, which is not specifically limited here.

[0061] See also Figure 3 In some embodiments, the silicon substrate 10 has a first edge 101 and a second edge 102 at both ends in the second direction, a first bus electrode 60 is provided at the first edge 101, and a second bus electrode 70 is provided at the second edge 102;

[0062] The first bus electrode 60 is electrically conductively connected to all the first fine grids 20 , and the second bus electrode 70 is electrically conductively connected to all the second fine grids 30 .

[0063] In this way, by respectively setting the first bus electrode 60 and the second bus electrode 70 at the first edge 101 and the second edge 102, the first bus electrode 60 can connect all the first fine grids 20 into a whole, and then conduct with the probe through the plurality of first test parts 41, and the second bus electrode 70 can connect all the second fine grids 30 into a whole, and then conduct with the probe through the plurality of first test parts 41.

[0064] Specifically, if Figure 3As shown, in such an embodiment, the first bus electrode 60 may be disposed near the first edge 101, and all the first fine grids 20 and all the second fine grids 30 are located on the side of the first bus electrode 60 facing the second edge 102. The second bus electrode 70 may be disposed near the second edge 102, and all the first fine grids 20 and all the second fine grids 30 are located on the side of the second bus electrode 70 facing the first edge 101. In other words, in this context, the first bus electrode 60 and the second bus electrode 70 are located at the two end positions of the first fine grid 20 and the second fine grid 30 in the first direction, respectively. There is no fine grid between the first bus electrode 60 and the first edge 101, and there is no fine grid between the second bus electrode 70 and the second edge 102.

[0065] In addition, in such an embodiment, the first bus electrode 60 and the second bus electrode 70 may not penetrate the back passivation layer and contact the doped layer below, and they only play the role of bus conduction. It is also possible that the first bus electrode 60 only contacts the doped layer located below the first bus electrode 60 and has the same polarity as the first bus electrode 60, and the second bus electrode 70 only contacts the doped layer located below the second bus electrode 70 and has the same polarity as the second bus electrode 70.

[0066] In some embodiments, in the second direction, the distance between the first bus electrode 60 and the first edge 101 is 0.5 mm-2 mm.

[0067] Thus, setting the distance between the first bus electrode 60 and the first edge 101 within this reasonable range can effectively avoid the distance between the two being too large, which would result in an excessively large area of ​​the edge region without fine grids and thus lead to excessive efficiency loss.

[0068] Specifically, in such an embodiment, the distance between the first bus electrode 60 and the first edge 101 can be, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or any value between 0.5mm-2mm, and is not limited here.

[0069] Similarly, in some embodiments, in the second direction, the distance between the second bus electrode 70 and the second edge 102 is 0.5 mm-2 mm.

[0070] Thus, setting the distance between the second bus electrode 70 and the second edge 102 within this reasonable range can effectively avoid the distance between the two being too large, which would result in an excessively large area of ​​the edge region without fine grids and thus cause excessive efficiency loss.

[0071] Specifically, in such an embodiment, the distance between the second bus electrode 70 and the second edge 102 can be, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or any value between 0.5mm-2mm, and is not limited here.

[0072] In some embodiments, the width of the first bus electrode 60 is greater than the width of the first fine grid 20 , and the width of the second bus electrode 70 is greater than the width of the second fine grid 30 .

[0073] In this way, by increasing the width of the first bus electrode 60 and the second bus electrode 70 , the transmission loss can be reduced.

[0074] Further, see Figure 3 and Figure 4 In some embodiments, the second fine grid 30 includes a first discontinuous fine grid 31 and a first continuous fine grid 32. The first continuous fine grid 32 does not cross the first test portion 41. The first discontinuous fine grid 31 crosses the first test portion 41 and is insulated from the first test portion 41. At least a portion of the first discontinuous fine grid 31 forms a first grid line segment 35 between the first test portion 41 and the first bus electrode 60. The first grid line segment 35 is insulated from the first test portion 41 and the first bus electrode 60. The first grid line segment 35 is connected to the first continuous fine grid 32 closest to the first grid line segment 35.

[0075] It is understandable that, because the polarity of the first gate line segment 35 is opposite to that of the first test portion 41, the first gate line segment 35 is an isolated gate line segment located between the first test portion 41 and the first edge 101, and the current collected by the first gate line segment 35 cannot be efficiently converged. Therefore, in this embodiment, by connecting the first gate line segment 35 to the adjacent first continuous fine grid 32, the current collected by the first gate line segment 35 can be converged to the adjacent first continuous fine grid 32, thereby achieving convergence, thereby improving the efficiency of the busbar-less back contact cell 100.

[0076] Further, see Figure 4 In such an embodiment, a first isolation region 23 is provided on the first fine gate 20 located between the first gate line segment 35 and the first continuous fine gate 32 closest to the first gate line segment 35, and the first gate line segment 35 and the first continuous fine gate 32 closest to the first gate line segment 35 are connected by a first connecting line 80 passing through the first isolation region 23 along the first direction.

[0077] In this way, by disposing the first isolation region 23 and the first connecting line 80 , the first gate line segment 35 can be converged and transmitted, thereby improving efficiency.

[0078] Specifically, in such an embodiment, the first connecting line 80 may not penetrate the back passivation layer and contact the doped layer below, so as to avoid leakage caused by contact with doped layers of different polarities. That is, in such an embodiment, the first connecting line 80 may only play the role of current collection and transmission, and does not contact the doped layer.

[0079] Of course, such an embodiment is only a preferred embodiment. It can be understood that in some embodiments, the first gate line segment 35 may not be connected to the adjacent first continuous fine gate 32 to achieve convergence (that is, the first isolation region 23 and the first connecting line 80 are not set), but the current transmission and convergence are achieved through the body region. No specific restrictions are made here.

[0080] See also Figure 4 In some embodiments, the number of first fine gates 20 crossing each first test portion 41 is three, and the number of second fine gates 30 crossing each first test portion 41 is two.

[0081] In this way, the area of ​​the first test portion 41 can be guaranteed while avoiding a large efficiency loss caused by an excessive number of first gate line segments 35 . At the same time, there is no need to form the first discontinuity region 23 on more first fine gates 20 .

[0082] Further, see Figure 3 and Figure 5 In some embodiments, the first fine gate 20 may include a second discontinuous fine gate 21 and a second continuous fine gate 22, the second continuous fine gate 22 does not cross the second test portion 51, the second discontinuous fine gate 21 crosses the second test portion 51 and is insulated from the second test portion 51, at least a portion of the second discontinuous fine gate 21 forms a second gate line segment 25 between the second test portion 51 and the second bus electrode 70, the second gate line segment 25 is insulated from the second test portion 51 and the second bus electrode 70; the second gate line segment 25 is connected to the second continuous fine gate 22 closest to the second gate line segment 25.

[0083] It is understandable that, because the second gate line segment 25 and the second test portion 51 have opposite polarities, the second gate line segment 25 is an isolated gate line segment located between the second test portion 51 and the second edge 102, and the current collected by the second gate line segment 25 cannot be efficiently converged. Therefore, in this embodiment, by connecting the second gate line segment 25 to the adjacent second continuous fine grid 22, the current collected by the second gate line segment 25 can be converged to the adjacent second continuous fine grid 22, thereby achieving convergence, thereby improving the efficiency of the busbar-less back contact battery 100.

[0084] Further, see Figure 5In such an embodiment, a second isolation region 33 is provided on the second fine gate 30 located between the second gate line segment 25 and the second continuous fine gate 22 closest to the second gate line segment 25, and the second gate line segment 25 and the second continuous fine gate 22 closest to the second gate line segment 25 are connected by a second connecting line 90 passing through the second isolation region 33 along the first direction.

[0085] In this way, by disposing the second isolation region 33 and the second connection line 90 , the current convergence transmission of the second gate line segment 25 can be achieved, thereby improving efficiency.

[0086] Specifically, in such an embodiment, the second connecting line 90 may not penetrate the back passivation layer and contact the doping layer below, so as to avoid leakage caused by contact with doping layers of different polarities. That is, in such an embodiment, the second connecting line 90 may only play the role of current convergence transmission and does not contact the doping layer.

[0087] Of course, it is not difficult to understand that such an embodiment is only a preferred embodiment. It is understandable that in some embodiments, the second gate line segment 25 may not be connected to the adjacent first continuous fine gate 32 to achieve convergence (that is, the second isolation area 33 and the second connecting line 90 are not set), but the current transmission and convergence are achieved through the body area. No specific restrictions are made here.

[0088] See also Figure 5 In some embodiments, the number of the second fine gates 30 crossing each second test portion 51 is three, and the number of the first fine gates 20 crossing each second test portion 51 is two.

[0089] In this way, the area of ​​the second test portion 51 can be guaranteed while avoiding a large efficiency loss caused by an excessive number of second gate line segments 25 . At the same time, there is no need to form the second discontinuity region 33 on more second fine gates 30 .

[0090] See also Figure 6 and Figure 7 In some embodiments, among the first discontinuous fine grids 31 intersecting the first test portion 41 , at least one first discontinuous fine grid 31 does not extend between the first test portion 41 and the first bus electrode 60 ;

[0091] On the extension line of the first discontinuous fine grid 31 that does not extend between the first test part 41 and the first bus electrode 60, the main grid-less back contact battery 100 is provided with a first reinforcement electrode 110. The first reinforcement electrode 110 is located between the first test part 41 and the first bus electrode 60 and its two ends are respectively connected to the first bus electrode 60 and the first test part 41.

[0092] In this way, by disposing the first enhancement electrode 110 , the loss during the process of merging to the first test portion 41 can be reduced, thereby improving efficiency.

[0093] Specifically, if Figure 7 As shown, such an embodiment is Figure 3 The embodiment shown differs in that Figure 3 One or more first gate line segments 35 are replaced with a first enhancement electrode 110 connecting the first bus electrode 60 and the first test portion 41 . The first enhancement electrode 110 may not penetrate the back passivation layer and contact the underlying doping layer to avoid short circuit.

[0094] In such an embodiment, in order to further reduce transmission loss, a conductive material may be filled in the space formed by the first reinforcement electrode 110 and the two adjacent first fine gates 20 .

[0095] In such an embodiment, since the carriers in the doped layer below the first enhancement electrode 110 cannot be directly collected by the second fine gate 30, but can only be collected by the second fine gate 30 through lateral transmission in the body region, in order to ensure efficiency, Figure 7 As shown, in the present application, each first test portion 41 may preferably be provided with only one corresponding first reinforcement electrode 110 .

[0096] In some embodiments, the width of the first reinforcement electrode 110 is greater than the widths of the first fine gate 20 and the second fine gate 30. In this way, by increasing the width of the first reinforcement electrode 110, transmission loss can be reduced.

[0097] See also Figure 6 and Figure 8 In some embodiments, among the second discontinuous fine grids 21 intersecting the second test portion 51 , at least one second discontinuous fine grid 21 does not extend between the second test portion 51 and the second bus electrode 70 ;

[0098] On the extension line of the second discontinuous fine grid 21 that does not extend to between the second test portion 51 and the second bus electrode 70, the main grid-less back contact battery 100 is provided with a second reinforcement electrode 120. The second reinforcement electrode 120 is located between the second test portion 51 and the second bus electrode 70 and its two ends are respectively connected to the second bus electrode 70 and the second test portion 51.

[0099] In this way, by disposing the second enhancement electrode 120 , the loss during the process of merging to the second testing portion 51 can be reduced, thereby improving efficiency.

[0100] Specifically, if Figure 8 As shown, such an embodiment is Figure 4 The difference between the embodiments in Figure 4One or more second gate line segments 25 are replaced with a second enhancement electrode 120 connecting the second bus electrode 70 and the second test portion 51 . The second enhancement electrode 120 may not penetrate the back passivation layer and contact the underlying doping layer to avoid short circuit.

[0101] In such an embodiment, in order to further reduce transmission loss, a conductive material may be filled in the space formed by the second enhancement electrode 120 and the two adjacent second fine gates 30 .

[0102] In such an embodiment, since the carriers in the doped layer below the second enhancement electrode 120 cannot be directly collected by the first fine gate 20, but can only be collected by the first fine gate 20 through lateral transmission in the body region, in order to ensure efficiency, as shown in FIG. Figure 8 As shown, in the present application, each second testing portion 51 may preferably be provided with only one corresponding second reinforcement electrode 120 .

[0103] In some embodiments, the width of the second reinforcement electrode 120 is greater than the widths of the first fine gate 20 and the second fine gate 30. In this way, by increasing the width of the second reinforcement electrode 120, transmission loss can be reduced.

[0104] See also Figure 9 In some embodiments, the silicon substrate 10 has a first edge 101 and a second edge 102 at both ends in the second direction, and a third edge 103 and a fourth edge 104 at both ends in the first direction.

[0105] Along the direction from the third edge 103 to the fourth edge 104, the back side 11 includes a first edge area 105, a middle area 107 and a second edge area 106. The first test portion 41 arranged in the first edge area 105 is a first edge test portion 411, the first test portion 41 arranged in the second edge area 106 is a second edge test portion 412, and the first test portion 41 arranged in the middle area 107 is a first middle test portion 413.

[0106] In which, the first edge test portion 411 is conductively connected to all the first fine gates 20 in the first edge region 105, and the second fine gates 30 in the first edge region 105 that cross the first edge test portion 411 all have first isolated segments 36 between the first edge test portion 411 and the first edge 101. In the first edge region 105, a first connecting electrode 130 connected to all the first isolated segments 36 is provided at the first edge 101, and the first connecting electrode 130 is also conductively connected to the second fine gates 30 in the first edge region 105 that do not cross the first edge test portion 411.

[0107] The second edge test portion 412 is conductively connected to all first fine gates 20 in the second edge region 106. The second fine gates 30 in the second edge region 106 that intersect the second edge test portion 412 each have a second isolated segment 37 between the second edge test portion 412 and the first edge 101. In the second edge region 106, a second connecting electrode 140 connected to all second isolated segments 37 is provided at the first edge 101. The second connecting electrode 140 is conductively connected to the second fine gates 30 in the second edge region 106 that do not intersect the second edge test portion 412.

[0108] In the middle region 107 , a third connecting electrode 150 is further provided at the first edge 101 . The third connecting electrode 150 connects all the first fine gates 20 in the middle region 107 .

[0109] Thus, the first and second connection electrodes 130 and 140 can be provided to connect isolated segments in the upper and lower edge regions, and the third connection electrode 150 can be provided to connect all first fine gates 20 in the middle region 107 .

[0110] Specifically, in such an embodiment, the first connection electrode 130, the third connection electrode 150, and the second connection electrode 140 can all extend along the first direction and be arranged at intervals. The first connection electrode 130, the third connection electrode 150, and the second connection electrode 140 can all be located at the ends of the first fine gate 20 and the second fine gate 30, and no fine gates can be provided between the first connection electrode 130, the third connection electrode 150, and the second connection electrode 140 and the first edge 101.

[0111] Furthermore, in such an embodiment, in the second direction, the distances between the first connection electrode 130 , the third connection electrode 150 , and the second connection electrode 140 and the first edge 101 may be 0.5 mm-2 mm.

[0112] In this way, it is possible to effectively avoid the situation where the spacing is too large, resulting in an excessively large area of ​​the edge region where fine grids are not provided, and thus causing excessive efficiency loss.

[0113] Specifically, in such an embodiment, the distance between the first connecting electrode 130, the third connecting electrode 150 and the second connecting electrode 140 and the first edge 101 may be, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm or any value between 0.5 mm and 2 mm, and is not limited here.

[0114] In some implementations, the widths of the first connection electrode 130 , the third connection electrode 150 , and the second connection electrode 140 are greater than the widths of the first fine gate 20 and the second fine gate 20 , thereby reducing transmission loss.

[0115] In such an embodiment, in order to ensure that during the test process, all first fine grids 20 can be combined together for test bus output, and all second fine grids 30 can also be combined together for test bus output, the following two embodiments can be used to achieve this:

[0116] First example: Please refer to Figure 9 In some embodiments, a fourth connection electrode 160 may be provided at the second edge 102 , and the fourth connection electrode 160 may be conductively connected to all the second test portions 51 and all the second fine gates 30 .

[0117] In this case, the first connection electrode 130 and the second connection electrode 140 can both be directly connected to the fourth connection electrode 160 via the second fine gate 30, thereby connecting all the second fine gates 30 together to achieve conduction with the probe. For the bus output of the first fine gates 20, during the test process, all the first fine gates 20 can be connected together by connecting the probes on the first edge test section 411, the second edge test section 412, and the first intermediate test section 413.

[0118] That is, in such an embodiment, the first connecting electrode 130 , the second connecting electrode 140 and the third connecting electrode 150 replace the first bus electrode 60 described above, and the fourth connecting electrode 160 is equivalent to the second bus electrode 70 described above.

[0119] In some implementations, the width of the fourth connection electrode 160 is greater than the widths of the first fine gate 20 and the second fine gate 20 , thereby reducing transmission loss.

[0120] In some embodiments, in the second direction, the distance between the fourth connection electrode 160 and the second edge 102 may be 0.5 mm-2 mm.

[0121] Specifically, in such an embodiment, the distance between the fourth connecting electrode 160 and the second edge 102 can be, for example, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, 2mm or any value between 0.5mm-2mm, and is not limited here.

[0122] Second embodiment: Please refer to Figure 10In some embodiments, the second test portion 51 disposed in the first edge region 105 is a third edge test portion 511 , the second test portion 51 disposed in the second edge region 106 is a fourth edge test portion 512 , and the second test portion 51 disposed in the middle region 107 is a second middle test portion 513 ;

[0123] The third edge test portion 511 is cross-connected with all second fine gates 30 in the first edge region 105. The first fine gates 20 in the first edge region 105 that cross the third edge test portion 511 each have a fourth isolated segment 26 between the third edge test portion 511 and the first edge 101. Within the first edge region 105, a fifth connection electrode 190 connected to all fourth isolated segments 26 is provided at the second edge 102. The fifth connection electrode 190 is also conductively connected to the first fine gates 20 in the first edge region 105 that do not cross the third edge test portion 511.

[0124] The fourth edge test portion 512 is cross-connected with all first fine gates 20 in the second edge region 106. The second fine gates 30 in the second edge region 106 that cross the fourth edge test portion 512 each have a fifth isolated segment 27 between the fourth edge test portion 512 and the first edge 101. Within the second edge region 106, a sixth connection electrode 1100 connected to all fifth isolated segments 27 is provided at the second edge 102. The sixth connection electrode 1100 is conductively connected to the first fine gates 20 in the second edge region 106 that do not cross the fourth edge test portion 512.

[0125] The fifth connection electrode 190 and the sixth connection electrode 1100 are both connected to the third connection electrode 150 through the first fine gate 20;

[0126] In the middle region 107 , a seventh connecting electrode 1110 is further provided at the second edge 102 . The seventh connecting electrode 1110 connects all the second fine gates 30 in the middle region 107 .

[0127] In this case, a first connecting electrode 130 and a fifth connecting electrode 190 are provided on both sides of the first edge region 105, a second connecting electrode 140 and a sixth connecting electrode 1100 are provided on both sides of the second edge region 106, and a third connecting electrode 150 and a seventh connecting electrode 1110 are provided on both sides of the middle region 107. The fifth connecting electrode 190 and the sixth connecting electrode 1100 are both connected to the third connecting electrode 150 via the first fine gates 20, thereby directly connecting all the first fine gates 20. For the bus output of the second fine gates 30, during the test process, the conduction of all the second fine gates 30 can be achieved by connecting the probes on the third edge test portion 511, the fourth edge test portion 512, and the second middle test portion 513.

[0128] Specifically, in such an embodiment, the fifth connection electrode 190, the seventh connection electrode 1110, and the sixth connection electrode 1100 can all extend along the first direction and be spaced apart. The fifth connection electrode 190, the seventh connection electrode 1110, and the sixth connection electrode 1100 can all be located at the ends of the first fine gate 20 and the second fine gate 30, and no fine gates can be provided between the fifth connection electrode 190, the seventh connection electrode 1110, and the sixth connection electrode 1100 and the second edge 102.

[0129] Furthermore, in such an embodiment, in the second direction, the distance between the fifth connection electrode 190 , the seventh connection electrode 1110 , and the sixth connection electrode 1100 and the second edge 102 may be 0.5 mm-2 mm.

[0130] In this way, it is possible to effectively avoid the situation where the spacing is too large, resulting in an excessively large area of ​​the edge region where fine grids are not provided, and thus causing excessive efficiency loss.

[0131] Specifically, in such an embodiment, the distance between the fifth connecting electrode 190, the seventh connecting electrode 1110 and the sixth connecting electrode 1100 and the second edge 102 may be, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm, 2 mm or any value between 0.5 mm and 2 mm, and is not limited here.

[0132] In some embodiments, the widths of the fifth connection electrode 190 , the seventh connection electrode 1110 , and the sixth connection electrode 1100 are greater than the widths of the first fine gate 20 and the second fine gate 20 , thereby reducing transmission loss.

[0133] See also Figure 11 In some embodiments, in the intermediate region 107, at least a portion of the second fine gate 30 crossing the first intermediate test portion 413 has a third isolated segment 38 (similar to the first gate line segment 35 described above) between the first intermediate test portion 413 and the third connection electrode 150, and the third isolated segment 38 is connected to the second fine gate 30 (similar to the first continuous fine gate 32 described above) that is closest to the third isolated segment 38 and does not cross the first intermediate test portion 413.

[0134] It is understood that because the third isolated segment 38 has an opposite polarity to the first intermediate test portion 413, the third isolated segment 38 is an isolated gate line segment located between the first intermediate test portion 413 and the first edge 101, and the current collected by the third isolated segment 38 cannot be efficiently converged. Therefore, in this embodiment, by connecting the third isolated segment 38 to the adjacent second fine grid 30, the current collected by the third isolated segment 38 can be converged to the adjacent second fine grid 30, thereby achieving convergence and improving the efficiency of the busbarless back contact cell 100.

[0135] Further, see Figure 11 In such an embodiment, a first discontinuity region 24 (similar to the first isolation region 23 described above) is provided on the first fine gate 20 located between the third isolated segment 38 and the second fine gate 30 closest to the third isolated segment 38. The third isolated segment 38 and the first fine gate 20 closest to the third isolated segment 38 are connected by a first bus bar 170 (similar to the first connecting line 80 described above) passing through the first discontinuity region 24 along a first direction.

[0136] In this way, by providing the first discontinuous area 24 and the first bus line 170 , the bus transmission of the third isolated segment 38 can be achieved, thereby improving efficiency.

[0137] Specifically, in such an embodiment, the first bus line 170 may not penetrate the back passivation layer and contact the doped layer below, so as to avoid contact with doped layers of different polarities and cause leakage. That is, in such an embodiment, the first bus line 170 may only play the role of bus transmission and does not contact the doped layer.

[0138] Of course, such an embodiment is only a preferred embodiment. It can be understood that in some embodiments, the third isolated segment 38 may not be connected to the adjacent first fine grid 20 to achieve busbar current (that is, the first discontinuity region 24 and the first bus line 170 are not provided), but the current transmission and busbar current are achieved through the body region. No specific limitation is made here.

[0139] In some embodiments, the number of first fine gates 20 crossing each first intermediate test portion 413 is three, and the number of second fine gates 30 crossing each first intermediate test portion 413 is two.

[0140] In this way, the area of ​​the first intermediate test portion 413 can be guaranteed, thereby avoiding a large efficiency loss caused by an excessive number of third isolated segments 38 . At the same time, there is no need to form the first discontinuous regions 24 on more first fine gates 20 .

[0141] See also Figure 12In some embodiments, among the second fine gates 30 intersecting the first intermediate test portion 413 , at least one second fine gate 30 does not extend between the first intermediate test portion 413 and the third connection electrode 150 (i.e., at least one second fine gate 30 does not have the third isolated segment 38 );

[0142] In this case, on the extension line of the second fine grid 30 that does not extend between the first intermediate test part 413 and the third connecting electrode 150, the main grid-less back contact battery 100 is provided with a first transmission electrode 180 (similar to the first enhancement electrode 110 mentioned above). The first transmission electrode 180 is located between the first intermediate test part 413 and the third connecting electrode 150 and its two ends are respectively connected to the first intermediate test part 413 and the third connecting electrode 150.

[0143] In this way, by disposing the first transmission electrode 180 , the loss during the process of merging to the first test portion 41 can be reduced, thereby improving efficiency.

[0144] Specifically, if Figure 12 As shown, such an embodiment is Figure 11 The difference between the embodiments in Figure 11 One or more of the third isolated segments 38 are replaced with a first transmission electrode 180 connecting the third connection electrode 150 and the first intermediate test portion 413 . The first transmission electrode 180 may not contact the underlying doping layer through the back passivation layer to avoid short circuit.

[0145] In such an embodiment, in order to further reduce transmission loss, a conductive material may be filled in the space formed between the first transmission electrode 180 and two adjacent first fine gates 20 .

[0146] In some embodiments, the width of the first transmission electrode 180 is greater than the widths of the first fine gate 20 and the second fine gate 30. In this way, by increasing the width of the first transmission electrode 180, transmission loss can be reduced.

[0147] See also Figure 10 and Figure 13 In some embodiments, in the intermediate region 107, at least a portion of the first fine gate 20 that crosses the second intermediate test portion 513 has a sixth isolated segment 28 (similar to the second gate line segment 25 described above) between the second intermediate test portion 513 and the seventh connection electrode 1110, and the sixth isolated segment 28 is connected to the first fine gate 20 (similar to the second continuous fine gate 22 described above) that is closest to the sixth isolated segment 28 and does not cross the second intermediate test portion 513.

[0148] It is understood that because the polarity of the sixth isolated segment 28 is opposite to that of the second intermediate test portion 513, the sixth isolated segment 28 is an isolated gate line segment located between the second intermediate test portion 513 and the first edge 101, and the current collected by it cannot be efficiently converged. Therefore, in this embodiment, by connecting the sixth isolated segment 28 to the adjacent first fine grid 20, the current collected by the sixth isolated segment 28 can be converged to the adjacent first fine grid 20, thereby achieving convergence, thereby improving the efficiency of the busbarless back contact cell 100.

[0149] See also Figure 13 In some embodiments, a second discontinuous region 34 (similar to the first discontinuous region 23 described above) is provided on the second fine gate 30 located between the sixth isolated segment 28 and the first fine gate 20 closest to the sixth isolated segment 28, and the sixth isolated segment 28 and the first fine gate 20 closest to the sixth isolated segment 28 are connected via a second bus bar 1120 (similar to the second connecting line 90 described above) passing through the second discontinuous region 34 along the first direction.

[0150] In this way, by providing the second discontinuous area 34 and the second bus line 1120 , the bus transmission of the sixth isolated segment 28 can be achieved, thereby improving efficiency.

[0151] Specifically, in such an embodiment, the second bus line 1120 may not penetrate the back passivation layer and contact the doped layer below, so as to avoid leakage caused by contact with doped layers of different polarities. That is, in such an embodiment, the second bus line 1120 may only play the role of bus transmission and not contact the doped layer.

[0152] Of course, such an embodiment is only a preferred embodiment. It can be understood that in some embodiments, the sixth isolated segment 28 may not be connected to the adjacent first fine grid 20 to achieve current convergence (that is, the second discontinuity area 34 and the second bus line 1120 are not set), but the current convergence is achieved through the body area. No specific limitation is made here.

[0153] See also Figure 13 In some embodiments, the number of the second fine gates 30 crossing each second intermediate test portion 513 is three, and the number of the first fine gates 20 crossing each second intermediate test portion 513 is two.

[0154] In this way, it is possible to avoid a large loss of efficiency due to an excessive number of sixth isolated segments 28 while ensuring the area of ​​the second intermediate test portion 513 .

[0155] See also Figure 14 In some embodiments, among the first fine gates 20 intersecting the second intermediate test portion 513 , at least one first fine gate 20 does not extend between the second intermediate test portion 513 and the seventh connection electrode 1110 ;

[0156] On the extension line of the first fine grid 20 that does not extend between the second intermediate test portion 513 and the seventh connecting electrode 1110, the main grid-less back contact battery 100 is provided with a second transmission electrode 1130 (similar to the first enhancement electrode 110 mentioned above). The second transmission electrode 1130 is located between the second intermediate test portion 513 and the seventh connecting electrode 1110 and its two ends are respectively connected to the second intermediate test portion 513 and the seventh connecting electrode 1110.

[0157] In this way, by disposing the second transmission electrode 1130 , the loss during the process of merging to the first test portion 41 can be reduced, thereby improving efficiency.

[0158] Specifically, if Figure 14 As shown, such an embodiment is Figure 13 The difference between the embodiments in Figure 13 One or more of the sixth isolated segments 28 are replaced with a second transmission electrode 1130 connecting the seventh connection electrode 1110 and the second intermediate test portion 513 . The second transmission electrode 1130 may not penetrate the back passivation layer and contact the underlying doping layer to avoid short circuit.

[0159] In such an embodiment, in order to further reduce transmission loss, a conductive material may be filled in the space formed between the second transmission electrode 1130 and two adjacent second fine gates 30 .

[0160] In some embodiments, the width of the second transmission electrode 1130 is greater than the widths of the first fine gate 20 and the second fine gate 30. In this way, by increasing the width of the second transmission electrode 1130, transmission loss can be reduced.

[0161] See also Figure 3 、 Figure 6 as well as Figure 9 and Figure 10 In some embodiments, all first test portions 41 are disposed close to the first edge 101 (i.e., the distance between the first test portion 41 and the first edge 101 is less than the distance between the first test portion 41 and the second edge 102 ) and are spaced apart and arranged in a row in the first direction;

[0162] All the second testing portions 51 are disposed close to the second edge 102 (ie, the distance between the second testing portion 51 and the second edge 102 is smaller than the distance between the second testing portion 51 and the first edge 101 ) and are arranged in a row in the first direction.

[0163] In this way, by arranging the first test parts 41 and the second test parts 51 in a row, the difficulty of the manufacturing process can be reduced.

[0164] In such an embodiment, the first test portions 41 are all used for welding with the welding ribbon; and / or the second test portions 51 are all used for welding with the welding ribbon.

[0165] In this way, the first test portion 41 and the second test portion 51 can be used for testing and also serve as welding points in the subsequent welding process of forming a battery string, thereby achieving functional reuse and reducing the use of slurry.

[0166] Specifically, in such an embodiment, it is preferred that both the first test portion 41 and the second test portion 51 are used for welding with a welding ribbon, and the polarity of the welding ribbon welded with the first test portion 41 is different from the polarity of the welding ribbon welded with the second test portion 51 .

[0167] In such an embodiment, in the second direction, the distance between the first test portion 41 and the first edge 101 is greater than or equal to 2 mm.

[0168] In this way, the first test portion 41 can be prevented from being too close to the first edge 101 and causing cracks during the welding process. In other words, this arrangement can reduce the risk of the first test portion 41 cracking during welding.

[0169] Further, in such an embodiment, in the second direction, the distance between the first test portion 41 and the first edge 101 is preferably 3 mm to 10 mm.

[0170] In this way, the risk of cracking can be reduced while preventing the first enhancement electrode 110 (first transmission electrode 180 ) disposed between the first test portion 41 and the first edge 101 from being too long, thereby causing the area of ​​the non-metallized doped region to be too large and affecting efficiency.

[0171] Specifically, in such an embodiment, the distance between the first test portion 41 and the first edge 101 may be, for example, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm or any value between 3 mm and 10 mm.

[0172] Furthermore, in some embodiments, in the second direction, the distance between the second testing portion 51 and the second edge 102 is greater than or equal to 2 mm.

[0173] In this way, the second testing portion 51 can be prevented from being too close to the second edge 102 and causing cracks during the welding process. In other words, this arrangement can reduce the risk of the second testing portion 51 cracking during welding.

[0174] Further, in such an embodiment, in the second direction, the distance between the second testing portion 51 and the second edge 102 is preferably 3 mm-10 mm.

[0175] In this way, the risk of cracking can be reduced while preventing the first enhancement electrode 110 (first transmission electrode 180 ) disposed between the second test portion 51 and the second edge 102 from being too long, thereby causing the area of ​​the non-metallized doped region to be too large and affecting efficiency.

[0176] Specifically, in such an embodiment, the distance between the second test portion 51 and the second edge 102 may be, for example, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or any value between 3mm-10mm.

[0177] See also Figure 15 In some embodiments, all of the first test portions 41 and the second test portions 51 may be disposed close to the first edge 101 , and in the first direction, the first test portions 41 and the second test portions 51 are alternately arranged in a row.

[0178] In this case, the first test section 41 and the second test section 51 are located in the same column. To avoid electrical leakage, the first test section 41 and the second test section 51 are not used for welding. Of course, in a possible embodiment, one of the first test section 41 and the second test section 51 can also be used for welding the welding ribbon. It is only necessary to cover the other with an insulating layer for insulation during welding.

[0179] See also Figure 16 In some embodiments, all of the first test sections 41 and the second test sections 51 are arranged close to the first edge 101 (that is, the distances between the first test sections 41 and the second test sections 51 and the first edge 101 are smaller than the distances between the first test sections 41 and the second test sections 51 and the second edge 102). In the first direction, the first test sections 41 and the second test sections 51 are alternately arranged, the first test sections 41 are arranged in a row, and the second test sections 51 are arranged in a row. In the first direction, the first test sections 41 are closer to the first edge 101 than the second test sections 51.

[0180] In this case, the first test portion 41 can be used for welding with the welding ribbon, and the second test portion 51 can also be used for welding.

[0181] See also Figure 17In some embodiments, the first test portion 41 closest to the third edge 103 (i.e., the first edge test portion 411 closest to the third edge 103 in the first edge area 105) includes a first welding portion 414 and a first connecting portion 415 connected to the first welding portion 414 on the side facing the third edge 103. The first welding portion 414 is used for welding to the welding ribbon. In the first direction, the distance between the first welding portion 414 and the third edge 103 is greater than 2 mm.

[0182] In this way, it is possible to avoid the distance between the first welding portion 414 and the third edge 103 being too small, which may easily lead to cracks during the welding process.

[0183] In such an embodiment, in the first direction, the distance between the first welding portion 414 and the third edge 103 is 3 mm-10 mm.

[0184] In this way, it is possible to avoid the distance between the first welding portion 414 and the third edge 103 being too small, which may easily cause cracks during the welding process, and it is also possible to avoid the distance being too large, which may cause excessive slurry usage and increase costs.

[0185] Specifically, the distance between the first welding portion 414 and the third edge 103 may be, for example, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or any value between 3mm-10mm.

[0186] In some embodiments, the first test portion 41 closest to the fourth edge 104 (and the first edge test portion 411 closest to the fourth edge 104 in the first edge area 105) includes a second welding portion 416 and a second connecting portion 417 connected to the second welding portion 416 on the side facing the fourth edge 104, and the second welding portion 416 is used for welding to the welding strip. In the first direction, the distance between the second welding portion 416 and the fourth edge 104 is greater than 2 mm.

[0187] In this way, it is possible to avoid the distance between the second welding portion 416 and the fourth edge 104 being too small, which may easily lead to cracks during the welding process.

[0188] In such an embodiment, in the first direction, the distance between the second welding portion 416 and the fourth edge 104 is 3 mm-10 mm.

[0189] In this way, it is possible to avoid the distance between the second welding portion 416 and the fourth edge 104 being too small, which may easily cause cracks during the welding process, and it is also possible to avoid the distance being too large, which may cause excessive slurry usage and increase costs.

[0190] Specifically, the distance between the second welding portion 416 and the fourth edge 104 may be, for example, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or any value between 3mm-10mm.

[0191] See also Figure 17 In some embodiments, the first test portion 51 closest to the third edge 103 (i.e., the third edge test portion 511 closest to the third edge 103 in the first edge area 105) includes a third welding portion 514 and a third connecting portion 515 connected to the third welding portion 514 on the side facing the third edge 103. The third welding portion 514 is used for welding to the welding strip. In the first direction, the distance between the third welding portion 514 and the third edge 103 is greater than 2 mm.

[0192] In this way, it is possible to avoid the distance between the third welding portion 514 and the third edge 103 being too small, which may easily lead to cracks during the welding process.

[0193] In such an embodiment, in the first direction, the distance between the third welding portion 514 and the third edge 103 is 3 mm-10 mm.

[0194] In this way, it is possible to avoid the distance between the third welding portion 514 and the third edge 103 being too small, which may easily cause cracks during the welding process, and it is also possible to avoid the distance being too large, which may cause excessive slurry usage and increase costs.

[0195] Specifically, the distance between the third welding portion 514 and the third edge 103 may be, for example, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or any value between 3mm-10mm.

[0196] In some embodiments, the second test portion 51 closest to the fourth edge 104 (and the fourth edge test portion 512 closest to the fourth edge 104 in the second edge area 106) includes a fourth welding portion 516 and a fourth connecting portion 517 connected to the fourth welding portion 516 on the side facing the fourth edge 104, and the fourth welding portion 516 is used for welding to the welding strip. In the first direction, the distance between the fourth welding portion 516 and the fourth edge 104 is greater than 2 mm.

[0197] In this way, it is possible to avoid the distance between the fourth welding portion 516 and the fourth edge 104 being too small, which may easily lead to cracks during the welding process.

[0198] In such an embodiment, in the first direction, the distance between the fourth welding portion 516 and the fourth edge 104 is 3 mm-10 mm.

[0199] In this way, it is possible to avoid the distance between the fourth welding portion 516 and the fourth edge 104 being too small, which may easily cause cracks during the welding process, and it is also possible to avoid the distance being too large, which may cause excessive slurry usage and increase costs.

[0200] Specifically, the distance between the fourth welding portion 516 and the fourth edge 104 may be, for example, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, 8.5mm, 9mm, 9.5mm, 10mm or any value between 3mm-10mm.

[0201] See also Figure 17 In some embodiments, within the first edge region 105 , the number of the first edge testing portion 411 and the number of the third edge testing portion 511 can be single, the first edge testing portion 411 is disposed close to the first edge 101 , and the third edge testing portion 511 is disposed close to the second edge 102 ;

[0202] A plurality of first PAD points 210 and a plurality of second PAD points 220 are further provided in the first edge region 105. The plurality of first PAD points 210 and the plurality of second PAD points 220 are alternately arranged along the second direction. In the second direction, the plurality of first PAD points 210 and the plurality of second PAD points 220 are both located between the first edge testing portion 411 and the third edge testing portion 511. The first PAD points 210 and the second PAD points 220 are both used for welding with the welding ribbon.

[0203] The first PAD point 210 is connected to the first fine gate 20 in the first edge region 105 and insulated from the second fine gate 30 . The second PAD point 220 is connected to the second fine gate 30 in the first edge region 105 and insulated from the first fine gate 20 .

[0204] In this way, the first PAD point 210 and the second PAD point 220 can be used as starting points for welding the welding ribbon, thereby improving welding reliability.

[0205] Specifically, in such an embodiment, the structure of one of the first PAD point 210 and the second PAD point 220 is the same as the first edge test portion 411 and is located on the same straight line as the first edge test portion 411 in the second direction, and the structure of the other one is the same as the third edge test portion 511 and is located on the same straight line as the third edge test portion 511 in the second direction.

[0206] Furthermore, in some embodiments, within the second edge region 106 , the number of the second edge testing portion 412 and the fourth edge testing portion 512 can be single, the second edge testing portion 412 is disposed close to the first edge 101 , and the fourth edge testing portion 512 is disposed close to the second edge 102 ;

[0207] A plurality of third PAD points 230 and a plurality of fourth PAD points 240 are further provided in the second edge region 106. The plurality of third PAD points 230 and the plurality of fourth PAD points 240 are alternately arranged along the second direction. In the second direction, the plurality of third PAD points 230 and the plurality of fourth PAD points 240 are all located between the second edge testing portion 412 and the fourth edge testing portion 512. The third PAD points 230 and the fourth PAD points 240 are both used for welding with the welding ribbon.

[0208] The third PAD point 230 is connected to the first fine gate 20 in the second edge region 106 and is insulated from the second fine gate 30 . The fourth PAD point 240 is connected to the second fine gate 30 in the second edge region 106 and is insulated from the first fine gate 20 .

[0209] The third PAD point 230 is aligned with the first PAD point 210 in the second direction, and the fourth PAD point 240 is aligned with the second PAD point 220 in the second direction.

[0210] In this way, the first PAD point 210 and the third PAD point 230 can serve as the starting point and the ending point of the same welding strip, and the second PAD point 220 and the third PAD point 230 can serve as the starting point and the ending point of the same welding strip, thereby further improving the reliability of welding.

[0211] Specifically, in such an embodiment, the structure of one of the third PAD point 230 and the fourth PAD point 240 is the same as the second edge test portion 412 and is located on the same straight line as the second edge test portion 412 in the second direction, and the structure of the other one is the same as the fourth edge test portion 512 and is located on the same straight line as the fourth edge test portion 512 in the second direction.

[0212] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0213] Although the embodiments of the present application have been shown and described, those skilled in the art will appreciate that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and intent of the present application, and that the scope of the present application is defined by the claims and their equivalents.

Claims

1. A busbar-less back contact battery, characterized in that: include: a silicon substrate having opposite front and back surfaces; a plurality of first fine grids and a plurality of second fine grids provided on the back surface, wherein the plurality of first fine grids and the plurality of second fine grids are alternately arranged in sequence along a first direction and extend along a second direction, wherein the second direction intersects the first direction; and a first test contact structure and a second test contact structure disposed on the back surface; Among them, the first test contact structure is conductively connected to all the first fine gates and crosses with several second fine gates, the second fine gates that cross the first test contact structure are disconnected at the first test contact structure, the second test contact structure is conductively connected to all the second fine gates and crosses with several first fine gates, the first fine gates that cross the second test contact structure are disconnected at the second test contact structure, and the first test contact structure and the second test contact structure are respectively used to contact probes of different polarities in the test device.

2. The busbar-less back contact cell according to claim 1, characterized in that: The first test contact structure includes a plurality of first test portions spaced apart from each other, each of the first test portions correspondingly intersecting a plurality of the first fine gates and a plurality of the second fine gates, and the second fine gates intersecting the first test portion are disconnected at the first test portion; The second test contact structure includes a plurality of second test portions arranged at intervals. Each of the first test portions crosses a plurality of the first fine gates and a plurality of the second fine gates. The first fine gates crossing the second test portion are disconnected at the second test portion.

3. The busbar-less back contact cell according to claim 2, characterized in that: The silicon substrate has a first edge and a second edge at both ends of the second direction, a first bus electrode is provided at the first edge, and a second bus electrode is provided at the second edge; The first bus electrode is conductively connected to all the first fine grids, and the second bus electrode is conductively connected to all the second fine grids.

4. The busbar-less back contact cell according to claim 3, characterized in that: The width of the first bus electrode is greater than the width of the first fine grid, and the width of the second bus electrode is greater than the width of the second fine grid; and / or The distance between the first bus electrode and the first edge is 0.5 mm to 2 mm; and / or The distance between the second bus electrode and the second edge is 0.5 mm-2 mm.

5. The busbar-less back contact cell according to claim 3, characterized in that: The second fine grid includes a first discontinuous fine grid and a first continuous fine grid, the first continuous fine grid does not cross the first test portion, the first discontinuous fine grid crosses the first test portion and is insulated and isolated from the first test portion, at least part of the first discontinuous fine grid forms a first gate line segment between the first test portion and the first bus electrode, the first gate line segment is insulated from the first test portion and the first bus electrode; the first gate line segment is connected to the first continuous fine grid closest to the first gate line segment.

6. The busbar-less back contact cell according to claim 5, characterized in that: A first isolation region is provided on the first fine gate located between the first gate line segment and the first continuous fine gate closest to the first gate line segment. The first gate line segment and the first continuous fine gate closest to the first gate line segment are connected by a first connecting line passing through the first isolation region along the first direction.

7. The busbar-less back contact cell according to claim 5, characterized in that: The number of the first fine gates crossing each of the first test portions is three, and the number of the second fine gates crossing each of the first test portions is two.

8. The busbar-less back contact cell according to claim 5, characterized in that: Among the first discontinuous fine grids intersecting the first test portion, at least one of the first discontinuous fine grids does not extend between the first test portion and the first bus electrode; On the extension line of the first discontinuous fine grid that does not extend between the first test part and the first bus electrode, the main grid-less back contact battery is provided with a first reinforcement electrode, and the first reinforcement electrode is located between the first test part and the first bus electrode and has its two ends connected to the first bus electrode and the first test part respectively.

9. The busbar-less back contact cell according to claim 8, characterized in that: The width of the first enhancement electrode is greater than the widths of the first fine gate and the second fine gate.

10. The busbar-less back contact cell according to claim 3, characterized in that: The first fine grid includes a second discontinuous fine grid and a second continuous fine grid, the second continuous fine grid does not intersect the second test portion, the second discontinuous fine grid intersects the second test portion and is insulated from the second test portion, at least a portion of the second discontinuous fine grid forms a second grid line segment between the second test portion and the second bus electrode, and the second grid line segment is insulated from the second test portion and the second bus electrode; The second gate line segment is connected to the second continuous fine gate closest to the second gate line segment.

11. The busbar-less back contact cell according to claim 10, characterized in that: A second isolation region is provided on the second fine gate located between the second gate line segment and the second continuous fine gate closest to the second gate line segment. The second gate line segment and the second continuous fine gate closest to the second gate line segment are connected via a second connecting line passing through the second isolation region along the first direction.

12. The busbar-less back contact cell according to claim 10, characterized in that: The number of the second fine gates crossing each second test portion is three, and the number of the first fine gates crossing each second test portion is two.

13. The busbar-less back contact cell according to claim 12, characterized in that: Among the second discontinuous fine grids intersecting the second test portion, at least one of the second discontinuous fine grids does not extend between the second test portion and the second bus electrode; On the extension line of the second discontinuous fine grid that does not extend between the second test part and the second bus electrode, the main grid-less back contact battery is provided with a second reinforcement electrode, and the second reinforcement electrode is located between the second test part and the second bus electrode and has its two ends connected to the second bus electrode and the second test part respectively.

14. The busbar-less back contact cell according to claim 13, characterized in that: The width of the second enhancement electrode is greater than the widths of the first fine gate and the second fine gate.

15. The busbar-less back contact cell according to claim 2, characterized in that: The silicon substrate has a first edge and a second edge at both ends of the second direction, and a third edge and a fourth edge at both ends of the first direction; Along the direction from the third edge to the fourth edge, the back surface includes a first edge region, a middle region, and a second edge region, the first test portion disposed in the first edge region is a first edge test portion, the first test portion disposed in the second edge region is a second edge test portion, and the first test portion disposed in the middle region is a first middle test portion; wherein the first edge test portion is conductively connected to all the first fine gates in the first edge region, and each of the second fine gates in the first edge region that crosses the first edge test portion has a first isolated segment between the first edge test portion and the first edge; within the first edge region, a first connecting electrode connected to all the first isolated segments is provided at the first edge, and the first connecting electrode is also conductively connected to each of the second fine gates in the first edge region that does not cross the first edge test portion; The second edge testing portion is conductively connected to all the first fine gates in the second edge region, and each of the second fine gates in the second edge region that crosses the second edge testing portion has a second isolated segment between the second edge testing portion and the first edge. In the second edge region, a second connecting electrode connected to all the second isolated segments is provided at the first edge, and the second connecting electrode is conductively connected to each of the second fine gates in the second edge region that does not cross the second edge testing portion. In the middle region, a third connecting electrode is further provided at the first edge, and the third connecting electrode connects all the first fine grids in the middle region.

16. The busbar-less back contact cell according to claim 15, characterized in that: In the second direction, the distance between the first connecting electrode, the third connecting electrode and the second connecting electrode and the first edge is 0.5 mm-2 mm; and / or Widths of the first connecting electrode, the third connecting electrode, and the second connecting electrode are greater than widths of the first fine gate and the second fine gate.

17. The busbar-less back contact cell according to claim 15, characterized in that: A fourth connecting electrode is provided at the second edge, and the fourth connecting electrode is conductively connected to all the second test portions and all the second fine grids.

18. The busbar-less back contact cell according to claim 17, characterized in that: In the second direction, the distance between the fourth connection electrode and the second edge is 0.5 mm to 2 mm; and or The fourth connecting electrode has a width greater than that of the first fine gate and the second fine gate.

19. The busbar-less back contact cell according to claim 15, characterized in that: In the middle region, the second fine gate that at least partially crosses the first middle test portion has a third isolated segment between the first middle test portion and the third connection electrode, and the third isolated segment is connected to the second fine gate that is closest to the third isolated segment and does not cross the first middle test portion.

20. The busbar-less back contact cell according to claim 19, characterized in that: A first discontinuous region is provided on the first fine grid located between the third isolated segment and the second fine grid closest to the third isolated segment. The third isolated segment and the first fine grid closest to the third isolated segment are connected by a first bus bar passing through the first discontinuous region along the first direction.

21. The busbar-less back contact cell according to claim 15, characterized in that: Among the second fine grids intersecting the first intermediate test portion, at least one of the second fine grids does not extend between the first intermediate test portion and the third connection electrode; On the extension line of the second fine grid that does not extend between the first intermediate test part and the third connecting electrode, the main grid-less back contact battery is provided with a first transmission electrode, and the first transmission electrode is located between the first intermediate test part and the third connecting electrode and has its two ends respectively connected to the first intermediate test part and the third connecting electrode.

22. The busbar-less back contact cell according to claim 21, characterized in that: The width of the first transfer electrode is greater than widths of the first fine gate and the second fine gate.

23. The busbar-less back contact cell according to claim 15, characterized in that: The second test portion provided in the first edge region is a third edge test portion, the second test portion provided in the second edge region is a fourth edge test portion, and the second test portion provided in the middle region is a second middle test portion; The third edge test portion is conductively connected to all the second fine gates in the first edge region, and the first fine gates in the first edge region that intersect the third edge test portion each have a fourth isolated segment between the third edge test portion and the first edge. Within the first edge region, a fifth connecting electrode connected to all the fourth isolated segments is provided at the second edge, and the fifth connecting electrode is also conductively connected to the first fine gates in the first edge region that do not intersect the third edge test portion. The fourth edge test portion is cross-connected with all the first fine gates in the second edge region, the second fine gates in the second edge region that cross the fourth edge test portion each have a fifth isolated segment between the fourth edge test portion and the first edge, and within the second edge region, a sixth connection electrode connected to all the fifth isolated segments is provided at the second edge, and the sixth connection electrode is conductively connected to the first fine gates in the second edge region that do not cross the fourth edge test portion; The fifth connecting electrode and the sixth connecting electrode are both connected to the third connecting electrode through the first fine grid; In the middle region, a seventh connecting electrode is further provided at the second edge, and the seventh connecting electrode connects all the second fine grids in the middle region.

24. The busbar-less back contact cell according to claim 23, characterized in that: In the second direction, the distance between the fifth connection electrode, the seventh connection electrode, and the sixth connection electrode and the second edge may be 0.5 mm-2 mm; and / or The widths of the fifth connection electrode, the seventh connection electrode, and the sixth connection electrode are all greater than the widths of the first fine gate and the second fine gate.

25. The busbar-less back contact cell according to claim 23, characterized in that: In the middle region, at least part of the first fine gate that crosses the second middle test portion has a sixth isolated segment between the second middle test portion and the third connection electrode, and the sixth isolated segment is connected to the first fine gate that is closest to the sixth isolated segment and does not cross the second middle test portion.

26. The busbar-less back contact cell according to claim 25, characterized in that: A second discontinuous region is provided on the second fine grid located between the sixth isolated segment and the first fine grid closest to the sixth isolated segment, and the sixth isolated segment and the first fine grid closest to the sixth isolated segment are connected by a second bus bar passing through the second discontinuous region along the first direction.

27. The busbar-less back contact cell according to claim 23, characterized in that: Among the first fine grids intersecting the second intermediate test portion, at least one of the first fine grids does not extend between the second intermediate test portion and the seventh connection electrode; On the extension line of the first fine grid that does not extend between the second intermediate test part and the seventh connecting electrode, the main grid-less back contact battery is provided with a second transmission electrode, and the second transmission electrode is located between the second intermediate test part and the seventh connecting electrode and has its two ends respectively connected to the second intermediate test part and the seventh connecting electrode.

28. The busbar-less back contact cell according to claim 27, characterized in that: The second transfer electrode has a width greater than widths of the first and second fine gates.

29. The busbar-less back contact cell according to claim 2, characterized in that: The silicon substrate has a first edge and a second edge at both ends of the second direction, and a third edge and a fourth edge at both ends of the first direction; All the first test parts are arranged close to the first edge and are arranged in a row in the first direction; all the second test parts are arranged close to the second edge and are arranged in a row in the first direction.

30. The busbar-less back contact cell according to claim 29, characterized in that: The first test parts are all used for welding with welding ribbons; and / or The second test parts are all used for welding with welding ribbons.

31. The busbar-less back contact cell according to claim 30, characterized in that: In the second direction, the distance between the first test portion and the first edge is greater than or equal to 2 mm; and / or, in the second direction, the distance between the second test portion and the second edge is greater than or equal to 2 mm.

32. The busbar-less back contact cell according to claim 31, characterized in that: In the second direction, the distance between the first test portion and the first edge is 3 mm-10 mm; and / or The distance between the second testing portion and the second edge is 3 mm to 10 mm.

33. The busbar-less back contact cell according to claim 2, characterized in that: The silicon substrate has a first edge and a second edge at both ends of the second direction, and a third edge and a fourth edge at both ends of the first direction; all the first test parts and the second test parts are arranged close to the first edge, and in the first direction, the first test parts and the second test parts are arranged alternately in a row.

34. The busbar-less back contact cell according to claim 2, characterized in that: The silicon substrate has a first edge and a second edge at both ends in the second direction, and a third edge and a fourth edge at both ends in the first direction; all the first test portions and the second test portions are arranged close to the first edge; In the first direction, the first test parts and the second test parts are alternately arranged at intervals, the first test parts are arranged in a row, and the second test parts are arranged in a row; in the first direction, the first test parts are closer to the first edge than the second test parts.

35. The busbar-less back contact cell according to claim 34, characterized in that: The first test parts are all used for welding with welding ribbons; and / or The second test parts are all used for welding with welding ribbons.

36. The busbar-less back contact cell according to claim 30 or 35, characterized in that: The first test portion closest to the third edge includes a first welding portion and a first connecting portion connected to the first welding portion on a side facing the third edge, the first welding portion being used for welding to a welding ribbon; the first test portion closest to the fourth edge includes a second welding portion and a second connecting portion connected to the second welding portion on a side facing the fourth edge, the second welding portion being used for welding to a welding ribbon; In the first direction, the distance between the first welding portion and the third edge is greater than 2 mm, and the distance between the second welding portion and the fourth edge is greater than 2 mm; and / or, The second test portion closest to the third edge includes a third welding portion and a third connecting portion connected to the third welding portion on a side facing the third edge, the third welding portion being used for welding to a welding ribbon; the second test portion closest to the fourth edge includes a fourth welding portion and a fourth connecting portion connected to the fourth welding portion on a side facing the fourth edge, the fourth welding portion being used for welding to a welding ribbon; In the first direction, a distance between the third welding portion and the third edge is greater than 2 mm, and a distance between the fourth welding portion and the fourth edge is greater than 2 mm.

37. The busbar-less back contact cell according to claim 36, characterized in that: In the first direction, the distance between the first welding portion and the third edge is 3 mm-10 mm, and the distance between the second welding portion and the fourth edge is 3 mm-10 mm; and / or, In the first direction, the distance between the third welding portion and the third edge is greater than 3 mm-10 mm, and the distance between the fourth welding portion and the fourth edge is 3 mm-10 mm.

38. The busbar-less back contact cell according to claim 23, characterized in that: In the first edge region, the number of the first edge testing portion and the number of the third edge testing portion are both single, the first edge testing portion is arranged close to the first edge, and the third edge testing portion is arranged close to the second edge. In the first edge region, a plurality of first PAD points and a plurality of second PAD points are further provided, the plurality of first PAD points and the plurality of second PAD points are alternately arranged along the second direction, and in the second direction, the plurality of first PAD points and the plurality of second PAD points are all located between the first edge testing portion and the third edge testing portion; Among them, the first PAD point and the second PAD point are both used for welding with the soldering ribbon, the first PAD point is connected to the first fine grid in the first edge area and is insulated from the second fine grid, and the second PAD point is connected to the second fine grid in the first edge area and is insulated from the first fine grid.

39. The busbar-less back contact cell according to claim 38, characterized in that: In the second edge region, the number of the second edge testing portion and the number of the fourth edge testing portion can be one, the second edge testing portion is arranged close to the first edge, and the fourth edge testing portion is arranged close to the second edge; A plurality of third PAD points and a plurality of fourth PAD points are further provided in the second edge region. The plurality of third PAD points and the plurality of fourth PAD points are alternately arranged along the second direction. In the second direction, the plurality of third PAD points and the plurality of fourth PAD points are all located between the second edge test portion and the fourth edge test portion. The third PAD points and the fourth PAD points are both used for welding with the welding ribbon. The third PAD point is connected to the first fine gate in the second edge region and insulated from the second fine gate, and the fourth PAD point is connected to the second fine gate in the second edge region and insulated from the first fine gate; The third PAD point is aligned with the first PAD point in the second direction, and the fourth PAD point is aligned with the second PAD point in the second direction.

40. A battery assembly, characterized in that: A busbar-free back contact cell comprising any one of claims 1-39.

41. A photovoltaic system, characterized in that: A battery assembly comprising the battery assembly of claim 40.

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