Back contact solar cell, cell module and photovoltaic system
By optimizing the design of the test structure pads for back-contact solar cells and reducing the gap width, the carrier collection effect of the fine grid was improved and the printing cost was reduced, thus solving the efficiency and cost problems of back-contact solar cells.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- ZHEJIANG AIKO SOLAR ENERGY TECH CO LTD
- Filing Date
- 2025-05-23
- Publication Date
- 2026-05-22
Smart Images
Figure CN224267200U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of solar cell technology, and in particular to a back-contact solar cell, a battery module and a photovoltaic system. Background Technology
[0002] Solar cells, also known as photovoltaic cells, are devices that directly convert light energy into direct current using the photovoltaic effect. Back-contact solar cells, with both positive and negative electrodes located on the back of the cell, completely avoid the shading caused by metal grid lines on the front surface, unlike bifacial solar cells. This eliminates optical losses due to metal grid line obstruction and significantly improves cell conversion efficiency.
[0003] In related technologies, back-contact solar cells typically have connecting pads on their back side for soldering ribbons to achieve series connection between cells. Simultaneously, since back-contact solar cells require current and voltage testing before leaving the factory, at least two test structures are usually required on their back side. Because the current and voltage test probes of the testing equipment need to simultaneously contact the test structures during performance testing, the test structures of back-contact solar cells must be relatively large. Typically, each test structure of a back-contact solar cell is a single large test pad, larger than the connecting pad, especially since the length of a single test pad is usually more than three times the length of the connecting pad. The large size of the test pad results in a larger discontinuity width at the test pad for the opposite polarity of the grid, leading to poor carrier collection at the test pad location and affecting cell efficiency. Furthermore, the large size of the test pad requires more paste for printing, resulting in higher printing costs for the test pads and consequently, higher printing costs for back-contact solar cells. Utility Model Content
[0004] This invention provides a back-contact solar cell, which aims to solve the problems of poor carrier collection effect and high printing cost of existing back-contact solar cells.
[0005] This invention is implemented by providing a back-contact solar cell, comprising:
[0006] Silicon substrate;
[0007] A plurality of first fine gates and a plurality of second fine gates are disposed on the back side of the silicon substrate, the plurality of first fine gates and the plurality of second fine gates are arranged alternately along a first direction, and the first fine gates and the second fine gates both extend along a second direction, the second direction intersecting the first direction;
[0008] At least one set of first pads are disposed on the back side of the silicon substrate, each set of first pads includes at least one first pad, and the first pads are electrically connected to the first fine gate.
[0009] At least one set of second pads are provided on the back side of the silicon substrate, each set of second pads includes at least one second pad, and the second pads are electrically connected to the second fine gate;
[0010] At least one first test structure is disposed on the back side of the silicon substrate. The first test structure includes two third pads spaced apart and electrically connected to each other along a first direction. The third pads are electrically connected to a first fine gate and spaced apart from a second fine gate. The third pads have the same dimensions as the first pads along the first direction and the same dimensions as the first pads along the second direction. The distance between two adjacent first pads along the first direction is greater than the distance between two third pads of the first test structure, or the distance between a third pad and an adjacent first pad along the first direction is greater than the distance between two third pads of the first test structure.
[0011] At least one second test structure is disposed on the back side of the silicon substrate. The second test structure includes two fourth pads that are adjacent to each other and electrically connected along the first direction. The fourth pads are electrically connected to the second fine gate and are spaced apart from the first fine gate. The fourth pads and the second pads have the same dimensions along the first direction and the fourth pads and the second pads have the same dimensions along the second direction. The distance between two adjacent second pads along the first direction is greater than the distance between two fourth pads of the second test structure, or the distance between a fourth pad and an adjacent second pad in the first direction is greater than the distance between two fourth pads of the second test structure.
[0012] Preferably, the first pad, the second pad, the third pad, and the fourth pad have the same shape and size.
[0013] Preferably, the distance between the two third pads of the first test structure is L2, the distance between two adjacent second fine gates is L5, L2 is greater than or equal to L5, and L2 is less than or equal to 3L5.
[0014] Preferably, the distance between the two fourth pads of the second test structure is L4, the distance between two adjacent first fine gates is L6, L4 is greater than or equal to L6, and L4 is less than or equal to 3L6.
[0015] Preferably, each group of first pads includes a plurality of first pads spaced apart along the first direction, and the ratio of the distance between two adjacent first pads along the first direction to the distance between the two third pads of the first test structure is 8 to 15; and / or, each group of second pads includes a plurality of second pads spaced apart along the first direction, and the ratio of the distance between two adjacent second pads along the first direction to the distance between the two fourth pads of the second test structure is 8 to 15.
[0016] Preferably, the ratio of the spacing between two adjacent first pads along the first direction to the spacing between the two third pads of the first test structure is 9 to 10; and / or, the ratio of the spacing between two adjacent second pads along the first direction to the spacing between the two fourth pads of the second test structure is 9 to 10.
[0017] Preferably, the spacing between the two third pads of the first test structure is greater than the length of the third pad; and / or, the spacing between the two fourth pads of the second test structure is greater than the length of the fourth pad.
[0018] Preferably, the spacing between the two third pads of the first test structure is less than or equal to twice the length of the third pad; the spacing between the two fourth pads of the second test structure is less than or equal to twice the length of the fourth pad.
[0019] Preferably, the first test structure includes a first connection portion connecting the two third pads, the width of the first connection portion being smaller than the width of the third pads, and the second fine gate forming a first interruption at the location of the first connection portion, the second fine gate being spaced apart from the first connection portion through the first interruption;
[0020] The second fine gate forms a second break at the location of the third pad, the second fine gate is spaced from the third pad through the second break, and the width of the first break is smaller than the width of the second break.
[0021] Preferably, the second test structure includes a second connection portion connecting the two fourth pads, the width of the second connection portion being smaller than the width of the fourth pads, and the first fine gate forming a third interruption at the location of the second connection portion, the first fine gate being spaced apart from the second connection portion through the third interruption;
[0022] The first fine gate forms a fourth break at the fourth pad position, the first fine gate is spaced apart from the fourth pad through the fourth break, and the width of the third break is smaller than the width of the fourth break.
[0023] Preferably, the width of the first pad is 3 to 5 times the width of the first connection portion; and / or, the width of the second pad is 3 to 5 times the width of the second connection portion.
[0024] Preferred, including:
[0025] A plurality of first main gates are disposed on the back side of the silicon substrate, the first main gates extending along the first direction and connected to the first fine gates, the first main gates being spaced apart from the second fine gates, and the first main gates having a plurality of first pads spaced sequentially along the first direction; the first test structure is disposed on the first main gates; and
[0026] A plurality of second main gates are disposed on the back side of the silicon substrate, and the plurality of second main gates and a plurality of first main gates are alternately arranged in sequence along the second direction. The second main gates extend along the first direction and are connected to the second fine gates. The second main gates are spaced apart from the first fine gates. A plurality of second pads are provided on the second main gates in sequence along the first direction. The second test structure is disposed on the second main gates.
[0027] This invention also provides a battery assembly, including the aforementioned back-contact solar cell.
[0028] This utility model also provides a photovoltaic system, including the above-mentioned battery components.
[0029] This utility model provides a back-contact solar cell by configuring a first test structure including two third pads spaced apart along a first direction. The third pads are the same size as the first pads, and the distance between two adjacent first pads along the first direction is greater than the distance between the two third pads in the first test structure, or the distance between a third pad and an adjacent first pad in the first direction is greater than the distance between the two third pads in the first test structure. Because the first test structure is configured with two spaced-apart third pads, there is no pad structure between the two third pads. Therefore, the width of the discontinuity in the second fine grid located between the two third pads can be reduced, thereby increasing the total length of the second fine grid and improving its performance. The carrier collection effect is improved, thereby enhancing battery efficiency. Simultaneously, the second test structure is configured to include two fourth pads spaced apart along a first direction. The fourth pads are the same size as the second pads, and the distance between two adjacent second pads along the first direction is greater than the distance between the two fourth pads of the second test structure, or the distance between a fourth pad and an adjacent second pad along the first direction is greater than the distance between the two fourth pads of the second test structure. Since there is no pad structure between the two fourth pads, the width of the discontinuity of the first fine gate located between the two fourth pads can be reduced, thereby increasing the total length of the first fine gate and improving the carrier collection effect of the first fine gate, thus improving battery efficiency. Furthermore, in related technologies, the length of a single test pad in a back-contact solar cell is typically more than three times the length of the connecting pad. In contrast, the sum of the lengths of the two third pads in the first test structure of this invention is only twice the length of the first pad, and the sum of the lengths of the two fourth pads in the second test structure is only twice the length of the second pad. This reduces the amount of solder paste used in the first and second test structures, lowering their printing costs and consequently reducing the printing cost of the back-contact solar cell, and ultimately, the production cost. Additionally, since the third pads are the same size as the first pads, and the fourth pads are the same size as the second pads, the design and printing of the back-contact solar cell pads are simplified. Attached Figure Description
[0030] Figure 1 A planar schematic diagram of a back-contact solar cell provided for an embodiment of this utility model;
[0031] Figure 2 A partial schematic diagram of a back-contact solar cell provided for an embodiment of this utility model;
[0032] Figure 3 An enlarged schematic diagram of the location of the first test structure of a back-contact solar cell provided in an embodiment of this utility model;
[0033] Figure 4This is an enlarged schematic diagram of the location of the second test structure for a back-contact solar cell provided in an embodiment of the present invention. Detailed Implementation
[0034] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. Examples of embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present utility model, and should not be construed as limiting the present utility model. Furthermore, it should be understood that the specific embodiments described herein are merely for explaining the present utility model and are not intended to limit the present utility model.
[0035] In the description of this utility model, it should be understood that the terms "upper", "lower", "back", "front", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0037] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the application of other processes and / or the use of other materials.
[0038] Please refer to Figures 1-4This utility model provides a back-contact solar cell, comprising:
[0039] Silicon substrate 1;
[0040] A plurality of first fine gates 2 and a plurality of second fine gates 3 are disposed on the back side 11 of the silicon substrate 1. The plurality of first fine gates 2 and the plurality of second fine gates 3 are arranged alternately along the first direction Y. The first fine gates 2 and the second fine gates 3 both extend along the second direction X, and the second direction X intersects the first direction Y.
[0041] At least one set of first pads 4 are provided on the back side 11 of the silicon substrate 1, each set of first pads 4 includes at least one first pad 4, and the first pad 4 is electrically connected to the first fine gate 2.
[0042] At least one set of second pads 5 are provided on the back side 11 of the silicon substrate 1, each set of second pads 5 includes at least one second pad 5, and the second pads 5 are electrically connected to the second fine gate 3;
[0043] At least one first test structure 6 is disposed on the back side 11 of a silicon substrate 1. The first test structure 6 includes two third pads 61 spaced apart along a first direction Y and electrically connected to each other. The third pads 61 are electrically connected to a first fine gate 2 and spaced apart from a second fine gate 3. The third pads 61 and the first pads 4 have the same dimensions along the first direction Y and the same dimensions along the second direction X. The distance L1 between two adjacent first pads 4 along the first direction Y is greater than the distance L2 between the two third pads 61 of the first test structure 6, or the distance L11 between a third pad 61 and an adjacent first pad 4 along the first direction Y is greater than the distance L2 between the two third pads 61 of the first test structure 6.
[0044] At least one second test structure 7 is disposed on the back side 11 of the silicon substrate 1. The second test structure 7 includes two fourth pads 71 that are adjacent to each other and electrically connected along a first direction Y. The fourth pads 71 are electrically connected to a second fine gate 3. The fourth pads 71 are spaced apart from a first fine gate 2. The fourth pads 71 and the second pads 5 have the same dimensions along the first direction Y. The fourth pads 71 and the second pads 5 have the same dimensions along a second direction X. The distance L3 between two adjacent second pads 5 along the first direction Y is greater than the distance L4 between the two fourth pads 71 of the second test structure 7, or the distance L12 between the fourth pad 71 and the adjacent second pad 5 in the first direction Y is greater than the distance L4 between the two fourth pads 71 of the second test structure 7.
[0045] In this embodiment of the invention, the back side 11 of the silicon substrate 1 is provided with multiple first fine grids 2 and multiple second fine grids 3 for collecting and transmitting photogenerated carriers, thereby realizing the power conversion of the back contact solar cell. The first fine grid 2 serves as either the positive or negative electrode, and the second fine grid 3 serves as either the positive or negative electrode. The back contact solar cell can be a gridless back contact solar cell, meaning that the back side 11 of the silicon substrate 1 does not have a main grid; the first pad 4 is directly printed on the first fine grid 2, and the second pad 5 is directly printed on the second fine grid 3. Alternatively, the back contact solar cell can have a main grid. Specifically, the back contact solar cell includes a first main grid 8 connected to the first fine grid 2 and a second main grid 9 connected to the second fine grid 3. The first pad 4 is printed on the first main grid 8, and the second pad 5 is printed on the second main grid 9. The accompanying drawings only illustrate the case of a back contact solar cell with a main grid. The number of first test structures 6 and second test structures 7 is the same. One first test structure 6 and one second test structure 7 form a pair of test structures for testing the electrical performance of back-contact solar cells. The first test structures 6 and second test structures 7 are arranged adjacent to each other, and the specific number of first test structures 6 and second test structures 7 is not limited. There can be 1, 2, 3 or 4 first test structures 6 and second test structures 7.
[0046] This embodiment of the invention provides a back-contact solar cell, which comprises at least one first test structure 6 and at least one second test structure 7 disposed on the back side 11 of a silicon substrate 1. The first test structure 6 includes two third pads 61 spaced apart along a first direction Y, and the third pads 61 are electrically connected to a first grid 2. The second test structure 7 includes two fourth pads 71 adjacent to each other along the first direction Y, and the fourth pads 71 are electrically connected to a second grid 3. The two third pads 61 of the first test structure 6 and the two fourth pads 71 of the second test structure 7 are used to contact the test probes of a test device. Of course, the two third pads 61 of the first test structure 6 and the two fourth pads 71 of the second test structure 7 can also be used to solder solder strips. When performing current and voltage tests on the back-contact cell, the current test probes of the test device contact one third pad 61 of the first test structure 6 and one fourth pad 71 of the second test structure 7, respectively, and the voltage test probes of the test device contact the other third pad 61 of the first test structure 6 and the other fourth pad 71 of the second test structure 7, thereby forming corresponding current test circuits and voltage test circuits.
[0047] In this embodiment of the invention, the first pad 4 and the third pad 61 have the same dimensions along the first direction Y, and the first pad 4 and the third pad 61 have the same dimensions along the second direction X. This can be understood as the first pad 4 and the third pad 61 having completely identical dimensions along the first direction Y or differing within the allowable range of processing errors, and the first pad 4 and the third pad 61 having completely identical dimensions along the second direction X or differing within the allowable range of processing errors. Similarly, the fourth pad 71 and the second pad 5 have the same dimensions along the first direction Y, and the fourth pad 71 and the second pad 5 have the same dimensions along the second direction X. This can be understood as the fourth pad 71 and the second pad 5 having completely identical dimensions along the first direction Y or differing within the allowable range of processing errors, and the fourth pad 71 and the second pad 5 having completely identical dimensions along the second direction X or differing within the allowable range of processing errors. The third pad 61 and the first pad 4 may have the same shape or different shapes. The fourth pad 71 and the second pad 5 may have the same shape or different shapes. Preferably, the third pad 61 has the same shape as the first pad 4, and the fourth pad 71 has the same shape as the second pad 5.
[0048] Please refer to Figure 2 and Figure 3 Specifically, the dimension of the third pad 61 along the first direction Y is the same as the dimension of the first pad 4 along the first direction Y, and the dimension of the third pad 61 along the second direction X is the same as the dimension of the first pad 4 along the second direction X. That is, the length W2 of the third pad 61 is equal to the length W4 of the first pad 4, and the width W1 of the third pad 61 is equal to the width W3 of the first pad 4. Please refer to... Figure 2 and Figure 4 The fourth pad 71 has the same dimensions as the second pad 5. This can be understood as the fourth pad 71 having the same dimensions along the first direction Y as the second pad 5 along the first direction Y, and the fourth pad 71 having the same dimensions along the second direction X as the second pad 5 along the second direction X. Specifically, the length W6 of the fourth pad 71 is equal to the length W8 of the second pad 5, and the width W5 of the fourth pad 71 is equal to the width W7 of the second pad 5. The second direction X is perpendicular to the first direction Y.
[0049] The specific shapes of the first pad 4, second pad 5, third pad 61, and fourth pad 71 are not limited and can be square, circular, pentagonal, hexagonal, heptagonal, octagonal, elliptical, etc. Of course, the first pad 4, second pad 5, third pad 61, and fourth pad 71 can also be other irregular shapes. The attached diagram only illustrates the case where the first pad 4, second pad 5, third pad 61, and fourth pad 71 are all octagonal.
[0050] This embodiment of the utility model provides a back-contact solar cell. A first test structure 6 is configured to include two third pads 61 spaced apart along a first direction Y. The third pads 61 have the same dimensions as the first pads 4 along the first direction Y. The third pads 61 have the same dimensions as the first pads 4 along a second direction X. The distance L1 between two adjacent first pads 4 along the first direction Y is greater than the distance L2 between the two third pads 61 of the first test structure 6, or the distance L11 between the third pad 61 and an adjacent first pad 4 along the first direction Y is greater than the distance L2 between the two third pads 61 of the first test structure 6. The distance L11 between the third pad 61 and an adjacent first pad 4 along the first direction Y is the distance from the third pad 61 to the first pad 4 closest to the third pad 61 along the first direction Y. L11 and L1 can be the same or different.
[0051] Because the first test structure 6 is configured as two small-sized third pads 61 spaced apart, with no pad structure between the two third pads 61, the width of the discontinuity of the second fine gate 3 located between the two third pads 61 can be reduced, thereby increasing the total length of the second fine gate 3, improving the carrier collection effect of the second fine gate 3, and thus improving the battery efficiency; simultaneously, the second test structure 7 is configured to include two small-sized fourth pads 71 spaced apart along the first direction Y, the fourth pads 71 having the same dimensions as the second pads 5 along the first direction Y, the fourth pads 71 and The second pads 5 have the same dimensions along the second direction X, and the distance L3 between two adjacent second pads 5 along the first direction Y is greater than the distance L4 between the two fourth pads 71 of the second test structure 7, or the distance L12 between the fourth pad 71 and the adjacent second pad 5 in the first direction Y is greater than the distance L4 between the two fourth pads 71 of the second test structure 7. The distance L12 between the fourth pad 71 and the adjacent second pad 5 in the first direction Y is the distance from the fourth pad 71 to the second pad 5 closest to the fourth pad 71 in the first direction Y. L12 and L3 can be the same or different. Since there is no pad structure between the two fourth pads 71, the width of the discontinuity of the first fine gate 2 located in the region between the two fourth pads 71 can be reduced, thereby increasing the total length of the first fine gate 2, improving the carrier collection effect of the first fine gate 2, and thus improving the battery efficiency.
[0052] Furthermore, in related technologies, the length (dimension along the first direction Y) of a single test pad in a back-contact solar cell is typically more than three times the length of the first or second pad. In contrast, the sum of the lengths W2 of the two third pads 61 of the first test structure 6 of this invention is only twice the length of the first pad 4, and the sum of the lengths W6 of the two fourth pads 71 of the first test structure 6 is only twice the length of the second pad 5. This significantly reduces the pad length dimensions of the first and second test structures 6 and 7, thereby reducing the amount of paste used and lowering the printing costs of the first and second test structures 6 and 7, ultimately reducing the printing costs of back-contact solar cells and consequently, the production costs. Additionally, since the third pads 61 are the same size as the first pad 4, and the fourth pads 71 are the same size as the second pad 5, the design and printing preparation of each pad are facilitated.
[0053] In this embodiment of the invention, the dimensions of the first pad 4 and the second pad 5 are those of conventional back-contact solar cell pads, and the dimensions of the first pad 4 and the second pad 5 can be flexibly set according to actual needs. The shape and dimensions of the first pad 4 and the second pad 5 can be the same or different. The number of groups of first pads 4 and second pads 5 is unlimited, and the first pads 4 and the second pads 5 can be set as a single group or multiple groups. Preferably, the back-contact solar cell includes multiple groups of first pads 4 and multiple groups of second pads 5, which are arranged alternately along the second direction X, and the number of groups of first pads 4 and the number of groups of second pads 5 are adapted to the number of solder ribbons. Furthermore, the number of first pads 4 in each group of first pads 4 and the number of second pads 5 in each group of second pads 5 is unlimited; each group of first pads 4 can include a single first pad 4 or multiple first pads 4; each group of second pads 5 can include a single second pad 5 or multiple second pads 5. Preferably, each group of first pads 4 includes a plurality of first pads 4 arranged at intervals along the first direction Y, and each group of second pads 5 includes a plurality of second pads 5 arranged at intervals along the first direction Y.
[0054] In a preferred embodiment of this utility model, the first pad 4, the second pad 5, the third pad 61, and the fourth pad 71 are all the same in shape and size. Since the first pad 4, the second pad 5, the third pad 61, and the fourth pad 71 are all the same in shape and size, there are only pads of a single shape and size on the entire battery cell, which makes it easier to design and print each pad.
[0055] As one embodiment of this utility model, it includes:
[0056] A plurality of first main gates 8 are disposed on the back side 11 of a silicon substrate 1. The first main gates 8 extend along a first direction Y and are connected to a first fine gate 2. The first main gates 8 are spaced apart from second fine gates 3. A plurality of first pads 4 are provided on the first main gates 8 at intervals along the first direction Y. A first test structure 6 is disposed on the first main gates 8.
[0057] A plurality of second main gates 9 are disposed on the back side 11 of the silicon substrate 1. The plurality of second main gates 9 and a plurality of first main gates 8 are alternately arranged along a second direction X. The second main gates 9 extend along a first direction Y and are connected to second fine gates 3. The second main gates 9 are spaced apart from the first fine gates 2. A plurality of second pads 5 are provided on the second main gates 9 at intervals along the first direction Y. A second test structure 7 is disposed on the second main gates 9. Optionally, the first test structure 6 and the second test structure 7 are respectively disposed on adjacent first main gates 8 and second main gates 9.
[0058] In this embodiment, the first main gate 8 is connected to multiple first fine gates 2. Each group of first pads 4 is disposed on the first main gate 8, and the number of groups of first pads 4 is the same as the number of first main gates 8. Each group of second pads 5 is disposed on the second main gate 9, and the number of groups of second pads 5 is the same as the number of second main gates 9. Two adjacent third pads 61 of the first test structure 6 are electrically connected through the first main gate 8. The second main gate 9 is connected to multiple second fine gates 3, and two adjacent fourth pads 71 of the second test structure 7 are electrically connected through the second main gate 9. The first main gate 8 is used to collect the corresponding charge carriers on the first fine gates 2, and the second main gate 9 is used to collect the corresponding charge carriers on the second fine gates 3. Due to the arrangement of the first main gate 8 and the second main gate 9, it is beneficial to collect charge carriers better and facilitate the printing and setting of pads and the soldering of pads and solder strips.
[0059] Please refer to the reference. Figures 2-4 As an embodiment of the present invention, the distance between the two third pads 61 of the first test structure 6 is L2, the distance between two adjacent second fine gates 3 is L5, L2 is greater than or equal to L5, and L2 is less than or equal to 3L5.
[0060] In this embodiment, each of the second fine grids 3 is arranged sequentially at equal intervals, and the distance L5 between two adjacent second fine grids 3 is the distance between two adjacent second fine grids 3 along the first direction Y. By controlling the distance L2 between the two third pads 61 of the first test structure 6 to be greater than or equal to L5 and less than or equal to 3L5, the distance L2 between the two third pads 61 is controlled within a suitable range. This prevents the distance L2 between the two third pads 61 from being too large, which would be inconvenient for contact testing of the current test probe and the voltage test probe, and also avoids the distance L2 between the two third pads 61 from being too small, which would result in an excessively large gap width of the second fine grid 3 between the two third pads 61. This facilitates the electrical performance testing of the back contact solar cell and improves the carrier collection effect of the second fine grid 3, thereby improving the cell efficiency.
[0061] In addition, if L2 is greater than or equal to L5 and L2 is less than or equal to 3L5, it can ensure that the number of non-pad areas spanning the second fine gate 3 between the two third pads 61 is 1 to 3. This can reduce the width design of the discontinuity of the 1 to 3 second fine gates 3 between the two third pads 61, thereby further improving the carrier collection effect of the second fine gate 3 and improving the battery efficiency.
[0062] As an embodiment of the present invention, the distance between the two fourth pads 71 of the second test structure 7 is L4, the distance between two adjacent first fine gates 2 is L6, L4 is greater than or equal to L6, and L4 is less than or equal to 3L6.
[0063] In this embodiment, the first fine grids 2 are arranged sequentially at equal intervals, and the distance between two adjacent first fine grids 2 is L6, which is the distance between two adjacent first fine grids 2 along the first direction Y. Optionally, the first fine grids 2 and the second fine grids 3 are arranged sequentially at equal intervals alternately, that is, L5 equals L6; the distance L4 between the two fourth pads 71 of the second test structure 7 is equal to the distance L2 between the two third pads 61 of the first test structure 6, which facilitates the design and printing of the back contact solar cell. In addition, optionally, the distance L1 between two adjacent first pads 4 along the first direction Y is equal to the distance L3 between two adjacent second pads 5 along the first direction Y.
[0064] In this embodiment, the distance L4 between the two fourth pads 71 of the second test structure 7 is controlled to be greater than or equal to L6, and less than or equal to 3L6. This controls the distance L4 between the two fourth pads 71 to be within a suitable range. This prevents the distance L4 between the two fourth pads 71 from being too large, which would make it difficult for the current test probe and voltage test probe to make contact tests. It also avoids the distance L4 between the two fourth pads 71 from being too small, which would result in an excessively large gap width of the first fine grid 2 between the two fourth pads 71. This facilitates the electrical performance testing of the back contact solar cell and helps to improve the carrier collection effect of the first fine grid 2, thereby improving the cell efficiency.
[0065] As an embodiment of the present invention, each group of first pads 4 includes a plurality of first pads 4 spaced apart along the first direction Y, and the ratio of the distance L1 between two adjacent first pads 4 along the first direction Y to the distance L2 between two third pads 61 of the first test structure 6 is 8 to 15.
[0066] In this embodiment, the ratio of the distance L1 between two adjacent first pads 4 along the first direction Y to the distance L2 between the two third pads 61 of the first test structure 6 is controlled to be 8~15. This is beneficial to the welding effect between the first pads 4 and the solder strip, and also facilitates the contact testing of the two third pads 61 of the first test structure 6 with the current test probe and voltage test probe of the test equipment, respectively. Moreover, it is also beneficial to improve the carrier collection effect of the second fine grid 3, thereby improving the battery efficiency.
[0067] As an embodiment of the present invention, the ratio of the distance L1 between two adjacent first pads 4 along the first direction Y to the distance L2 between two third pads 61 of the first test structure 6 is 9 to 10.
[0068] In this embodiment, the ratio of the distance L1 between two adjacent first pads 4 along the first direction Y to the distance L2 between the two third pads 61 of the first test structure 6 is further controlled to be 9~10, which not only further improves the welding effect between the first pads 4 and the solder strip, but also facilitates the contact testing of the two third pads 61 of the first test structure 6 with the current test probe and the voltage test probe, respectively.
[0069] As an embodiment of the present invention, each group of second pads 5 includes a plurality of second pads 5 spaced apart along the first direction Y, and the ratio of the distance L3 between two adjacent second pads 5 along the first direction Y to the distance L4 between the two fourth pads 71 of the second test structure 7 is 8 to 15.
[0070] In this embodiment, the ratio of the spacing L3 between two adjacent second pads 5 along the first direction Y to the spacing L4 between the two fourth pads 71 of the second test structure 7 is 8-15. This ratio is beneficial for the welding effect between the second pads 5 and the solder strip, and also facilitates the contact between the two fourth pads 71 of the second test structure 7 and the current test probe and voltage test probe of the test equipment to complete the test. Furthermore, it also helps to improve the carrier collection effect of the first fine gate 2, thereby improving the battery efficiency. Further, the ratio of the spacing L3 between two adjacent second pads 5 to the spacing L4 between the two fourth pads 71 of the second test structure 7 is 9-10. This ratio is beneficial for the welding effect between the second pads 5 and the solder strip, and further facilitates the contact between the two fourth pads 71 of the second test structure 7 and the current test probe and voltage test probe.
[0071] As an embodiment of the present invention, the distance L2 between the two third pads 61 of the first test structure 6 is greater than the length W2 of the third pad 61; the distance L4 between the two fourth pads 71 of the second test structure 7 is greater than the length W6 of the fourth pad 71.
[0072] In this embodiment, the distance L2 between the two third pads 61 of the first test structure 6 is the distance between the two third pads 61 along the first direction Y, and the length W2 of the third pad 61 is the dimension of the third pad 61 along the first direction Y. Since the distance L2 between the two third pads 61 of the first test structure 6 is greater than the length W2 of the third pad 61, it is beneficial for a larger number of first fine gates 2 to reduce the width of the gap in the region between the two third pads 61, which is beneficial for further improving the carrier collection effect of the second fine gate 3, thereby improving the battery efficiency. Similarly, the distance L4 between the two fourth pads 71 of the second test structure 7 is greater than the length W6 of the fourth pad 71, and the length W6 of the fourth pad 71 is the dimension of the fourth pad 71 along the first direction Y. This is beneficial for a larger number of first fine gates 2 to reduce the width of the gap in the region between the two fourth pads 71, which is beneficial for further improving the carrier collection effect of the first fine gate 2, thereby improving the battery efficiency.
[0073] As an embodiment of the present invention, the distance L2 between the two third pads 61 of the first test structure 6 is less than or equal to twice the length W2 of the third pad 61; the distance L4 between the two fourth pads 71 of the second test structure 7 is less than or equal to twice the length W6 of the fourth pad 71.
[0074] In this embodiment, the spacing L2 between the two third pads 61 of the first test structure 6 is controlled to be less than or equal to twice the length W2 of the third pad 61, and the spacing L4 between the two fourth pads 71 of the second test structure 7 is controlled to be less than or equal to twice the length W6 of the fourth pad 71. This can prevent the spacing L2 between the two third pads 61 and the spacing L4 between the two fourth pads 71 from being too large, which would make it inconvenient for the current test probe and the voltage test probe to make contact tests. It can also prevent the spacing L2 between the two third pads 61 and the spacing L4 between the two fourth pads 71 from being too small. This can reduce the design of the discontinuity width of the second fine gate 3 between the two third pads 61 and the design of the discontinuity width of the first fine gate 2 between the two fourth pads 71, which is beneficial to improving the carrier collection effect of the fine gate, thereby improving the battery efficiency.
[0075] As an embodiment of the present invention, the first test structure 6 includes a first connecting portion 62 connecting two third pads 61. The width of the first connecting portion 62 is smaller than the width W1 of the third pads 61. A second fine gate 3 forms a first interruption 31 at the position of the first connecting portion 62. The second fine gate 3 is spaced apart from the first connecting portion 62 through the first interruption 31.
[0076] The second fine gate 3 forms a second interruption 32 at the position of the third pad 61. The second fine gate 3 is separated from the third pad 61 by the second interruption 32, and the width L7 of the first interruption 31 is smaller than the width L8 of the second interruption 32.
[0077] In this embodiment, the two third pads 61 are electrically connected through the first connecting portion 62. The first connecting portion 62 can be part of the first main gate 8. The two third pads 61 are directly printed on the first main gate 8, or the first connecting portion 62 can be printed separately. The width directions of the third pads 61, the first interruption 31, and the second interruption 32 are all along the second direction X. Since the width of the first interruption 31 is smaller than the width of the second interruption 32, that is, the interruption width of the second fine gate 3 located at the first connecting portion 62 is smaller than the interruption width of the second fine gate 3 located at the first pad 4, the width of the first interruption 31 of the second fine gate 3 at the first connecting portion 62 can be reduced, the total length of the second fine gate 3 at the first connecting portion 62 can be increased, and the carrier collection effect of the second fine gate 3 at the first connecting portion 62 can be improved, thereby improving the battery efficiency.
[0078] As an embodiment of the present invention, the second test structure 7 includes a second connecting portion 72 connecting two fourth pads 71. The width of the second connecting portion 72 is smaller than the width W5 of the fourth pads 71. The first fine gate 2 forms a third interruption 21 at the position of the second connecting portion 72. The first fine gate 2 is spaced apart from the second connecting portion 72 through the third interruption 21.
[0079] The first fine gate 2 forms a fourth break 22 at the position of the fourth pad 71. The first fine gate 2 is separated from the fourth pad 71 by the fourth break 22, and the width L9 of the third break 21 is smaller than the width L10 of the fourth break 22.
[0080] In this embodiment, the two fourth pads 71 are electrically connected through the second connection portion 72. The second connection portion 72 can be part of the second main gate 9. The two fourth pads 71 are directly printed on the second main gate 9, or the second connection portion 72 can be printed separately. The width directions of the fourth pads 71, the third interruption 21, and the fourth interruption 22 are all along the second direction X. Since the width of the third interruption 21 is smaller than the width of the fourth interruption 22, the width of the third interruption 21 of the first fine gate 2 at the second connection portion 72 can be reduced, the length of the first fine gate 2 at the second connection portion 72 can be increased, and the carrier collection effect of the first fine gate 2 at the second connection portion 72 can be improved, thereby improving the battery efficiency.
[0081] As an embodiment of this utility model, the width of the first pad 4 is 3 to 5 times the width of the first connection portion 62; the width of the second pad 5 is 3 to 5 times the width of the second connection portion 72, which can further improve the carrier collection effect of the second fine gate 3 at the position of the first connection portion 62 and improve the carrier collection effect of the first fine gate 2 at the position of the second connection portion 72, thereby improving the battery efficiency.
[0082] As an embodiment of this utility model, the width of the first connecting part 62 is uniformly set, which facilitates the printing and processing of the first test structure 6.
[0083] In some other embodiments, the width of the middle position of the first connection portion 62 is smaller than the width of the first connection portion 62 near the third pad 61. That is, the width of the first connection portion 62 near the middle position is smaller than the width of the first connection portion 62 near the third pad 61. This makes the width of the middle position of the first connection portion 62 smaller than the width of its two ends, which further reduces the width of the discontinuity of the second fine gate 3 at the first connection portion 62, further improving the carrier collection effect of the second fine gate 3, thereby improving battery efficiency. Similarly, the width of the middle position of the second connection portion 72 is smaller than the width of the second connection portion 72 near the fourth pad 71. That is, the width of the second connection portion 72 near the middle position is smaller than the width of the second connection portion 72 near the fourth pad 71. This makes the width of the middle position of the second connection portion 72 smaller than the width of its two ends, which further reduces the width of the discontinuity of the first fine gate 2 at the second connection portion 72, further improving the carrier collection effect of the second fine gate 3, thereby improving battery efficiency.
[0084] This utility model embodiment also provides a battery assembly, which includes the back-contact solar cell of the above embodiment. It should be noted that the battery assembly has the same or similar beneficial effects as the back-contact solar cell, and the related parts between the two can be referred to each other. To avoid repetition, they will not be described again here.
[0085] This utility model embodiment also provides a photovoltaic system, which includes the battery module described in the above embodiment. It should be noted that this photovoltaic system has the same or similar beneficial effects as the battery module described above, and the related aspects between the two can be referred to each other; to avoid repetition, they will not be repeated here.
[0086] In this embodiment, the photovoltaic system can be applied in photovoltaic power plants, such as ground-mounted power plants, rooftop power plants, and floating power plants. It can also be applied to equipment or devices that utilize solar energy to generate electricity, such as user solar power supplies, solar streetlights, solar cars, and solar buildings. Of course, it is understood that the application scenarios of the photovoltaic system are not limited to these; that is, the photovoltaic system can be applied in all fields that require solar energy to generate electricity. Taking a photovoltaic power generation system network as an example, the photovoltaic system may include a photovoltaic array, a combiner box, and an inverter. The photovoltaic array may be an array combination of multiple battery modules; for example, multiple battery modules can form multiple photovoltaic arrays. The photovoltaic array is connected to the combiner box, which can collect the current generated by the photovoltaic array. The collected current flows through the inverter and is converted into AC power required by the mains power grid before being connected to the mains power grid to achieve solar power supply.
[0087] In the description of this specification, references to terms such as "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0088] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A back-contact solar cell, characterized in that, include: Silicon substrate; A plurality of first fine gates and a plurality of second fine gates are disposed on the back side of the silicon substrate, the plurality of first fine gates and the plurality of second fine gates are arranged alternately along a first direction, and the first fine gates and the second fine gates both extend along a second direction, the second direction intersecting the first direction; At least one set of first pads are disposed on the back side of the silicon substrate, each set of first pads including at least one first pad, the first pad being electrically connected to the first fine gate; At least one set of second pads are provided on the back side of the silicon substrate, each set of second pads includes at least one second pad, and the second pads are electrically connected to the second fine gate; At least one first test structure is disposed on the back side of the silicon substrate. The first test structure includes two third pads that are spaced apart and electrically connected to each other along a first direction. The third pads are electrically connected to a first fine gate and spaced apart from a second fine gate. The third pads have the same dimensions as the first pads along the first direction and the same dimensions as the first pads along the second direction. The distance between two adjacent first pads along the first direction is greater than the distance between two third pads of the first test structure, or the distance between a third pad and an adjacent first pad in the first direction is greater than the distance between two third pads of the first test structure. and At least one second test structure is disposed on the back side of the silicon substrate. The second test structure includes two fourth pads that are adjacent to each other and electrically connected along the first direction. The fourth pads are electrically connected to the second fine gate and are spaced apart from the first fine gate. The fourth pads and the second pads have the same dimensions along the first direction and the fourth pads and the second pads have the same dimensions along the second direction. The distance between two adjacent second pads along the first direction is greater than the distance between two fourth pads of the second test structure, or the distance between a fourth pad and an adjacent second pad in the first direction is greater than the distance between two fourth pads of the second test structure.
2. The back-contact solar cell according to claim 1, characterized in that, The first pad, the second pad, the third pad, and the fourth pad are all the same in shape and size.
3. The back-contact solar cell according to claim 1, characterized in that, The distance between the two third pads of the first test structure is L2, the distance between two adjacent second fine gates is L5, L2 is greater than or equal to L5, and L2 is less than or equal to 3L5.
4. The back-contact solar cell according to claim 1 or 3, characterized in that, The distance between the two fourth pads of the second test structure is L4, the distance between two adjacent first fine gates is L6, L4 is greater than or equal to L6, and L4 is less than or equal to 3L6.
5. The back-contact solar cell according to claim 1, characterized in that, Each group of first pads includes a plurality of first pads spaced apart along the first direction, wherein the ratio of the distance between two adjacent first pads along the first direction to the distance between the two third pads of the first test structure is 8 to 15; and / or, each group of second pads includes a plurality of second pads spaced apart along the first direction, wherein the ratio of the distance between two adjacent second pads along the first direction to the distance between the two fourth pads of the second test structure is 8 to 15.
6. The back-contact solar cell according to claim 5, characterized in that, The ratio of the spacing between two adjacent first pads along the first direction to the spacing between two third pads of the first test structure is 9 to 10; and / or the ratio of the spacing between two adjacent second pads along the first direction to the spacing between two fourth pads of the second test structure is 9 to 10.
7. The back-contact solar cell according to claim 1, characterized in that, The spacing between the two third pads of the first test structure is greater than the length of the third pad; and / or, the spacing between the two fourth pads of the second test structure is greater than the length of the fourth pad.
8. The back-contact solar cell according to claim 1, characterized in that, The spacing between the two third pads of the first test structure is less than or equal to twice the length of the third pad; the spacing between the two fourth pads of the second test structure is less than or equal to twice the length of the fourth pad.
9. The back-contact solar cell according to claim 1, characterized in that, The first test structure includes a first connection portion connecting two of the third pads, the width of the first connection portion being smaller than the width of the third pads, and a second fine gate forming a first interruption at the location of the first connection portion, the second fine gate being spaced apart from the first connection portion through the first interruption; The second fine gate forms a second break at the location of the third pad, the second fine gate is spaced from the third pad through the second break, and the width of the first break is smaller than the width of the second break.
10. The back-contact solar cell according to claim 9, characterized in that, The second test structure includes a second connection portion connecting two of the fourth pads, the width of the second connection portion being smaller than the width of the fourth pads, and the first fine gate forming a third gap at the location of the second connection portion, the first fine gate being spaced apart from the second connection portion through the third gap; The first fine gate forms a fourth break at the fourth pad position, the first fine gate is spaced apart from the fourth pad through the fourth break, and the width of the third break is smaller than the width of the fourth break.
11. The back-contact solar cell according to claim 10, characterized in that, The width of the first pad is 3 to 5 times the width of the first connection portion; and / or, the width of the second pad is 3 to 5 times the width of the second connection portion.
12. The back-contact solar cell according to claim 1, characterized in that, include: A plurality of first main gates are disposed on the back side of the silicon substrate, the first main gates extending along the first direction and connected to the first fine gates, the first main gates being spaced apart from the second fine gates, and the first main gates having a plurality of first pads spaced sequentially along the first direction; the first test structure is disposed on the first main gates; and A plurality of second main gates are disposed on the back side of the silicon substrate, and the plurality of second main gates and a plurality of first main gates are alternately arranged in sequence along the second direction. The second main gates extend along the first direction and are connected to the second fine gates. The second main gates are spaced apart from the first fine gates. A plurality of second pads are provided on the second main gates in sequence along the first direction. The second test structure is disposed on the second main gates.
13. A battery assembly, characterized in that, Includes the back-contact solar cell according to any one of claims 1 to 12.
14. A photovoltaic system, characterized in that, Includes the battery assembly as described in claim 13.