Solar cell and photovoltaic module
By employing a grid structure with a dual-channel transmission mode in solar cells, the problem of poor welding caused by insufficient grid height was solved, achieving stable current transmission and improved efficiency, while reducing module rework rate and cost.
Patent Information
- Application Number
- CN202423187513.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2034-12-24
AI Technical Summary
Insufficient grid height in existing solar cells leads to poor welding. The solder ribbon and silver paste undergo a silver-eating reaction at high temperatures, affecting current transmission. Furthermore, existing TOPCon technology increases wet weight and shading, impacting efficiency.
A dual-channel transmission mode is adopted, with multiple pairs of spaced main grid lines and auxiliary grid lines. Conductive connectors are placed between the main grid lines to form a dual connection path, increasing the welding window and opening a new current collection channel. The centipede-foot structure is eliminated to save slurry and reduce the shading area.
It effectively solves the problem of weld breakage, reduces component rework rate, increases current transmission path, reduces cost and improves photoelectric conversion efficiency.
Smart Images
Figure CN223859565U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to photovoltaic technology field, specifically, a solar cell and photovoltaic module are related. BACKGROUND
[0002] At present, photovoltaic technology is changing at a speed of changing with each new day, and efficiency improvement and cost reduction are constantly updated and iterated. The finer and shorter grid lines will bring greater wet weight and efficiency benefits. However, the risk brought by the low height of the fine grid is that the welding of the component solder strip is poor. Component preparation has always been a key downstream processing link of the cell sheet, and the welding problem has always been a difficulty in the production and preparation of the cell sheet.
[0003] The existing cell sheet production mode is step printing, that is, the cell sheet pattern formed by the matching printing of the main grid and the fine grid can ensure that the main grid part that needs to be welded and transmit current matches the silver paste base for welding, and the fine grid part that needs to collect and summarize the current is superimposed on the basis after the main grid is printed. The advantage of this is that the functions of the main grid and the fine grid are separated, which can minimize the consumption of a part of the silver paste, and by reducing the line width and line height of the grid line, the cost control of the cell sheet can be realized without affecting the overall efficiency. However, the solder strip and the silver paste will have a silver corrosion reaction at high temperature, and the insufficient height of the cell sheet grid line will affect the final welding yield. When the silver is completely corroded by the tin, the solder will be broken, which will cause poor current transmission.
[0004] In addition, the existing TOPCon technology adopts centipede foot secondary printing, that is, on the basis of the existing two-four printing with fine grid of centipede foot, the printing of the centipede foot area in the front and back main grid is increased again, so as to achieve the required grid line height of the welding window. The result of this is that it will increase the wet weight. At the same time, because the main grid paste has stronger widening performance, it will have a greater impact on the shading of the cell sheet. Because the main grid paste is printed before the fine grid, the corrosion ability of the main grid to the silicon sheet is not strong, and it cannot form effective ohmic contact, so it will also cause efficiency loss.
[0005] Therefore, there is an urgent need to provide a new grid line electrode structure that can effectively solve the problem of poor conduction caused by solder breakage after reducing the height of the grid line. Utility model content
[0006] The purpose of the utility model includes providing a solar cell and photovoltaic module, which can avoid the problem of poor conduction caused by solder breakage after reducing the height of the grid line.
[0007] The embodiment of the utility model can be implemented as follows:
[0008] In a first aspect, the utility model provides a solar cell, which comprises a cell sheet and a grid line electrode, the grid line electrode is arranged on the surface of the cell sheet and forms ohmic contact with the cell sheet.
[0009] The grid line electrode comprises a plurality of pairs of main grid lines, a plurality of auxiliary grid lines and a plurality of conductive connecting pieces, the plurality of pairs of main grid lines are arranged at intervals, and each pair of main grid lines is connected with the plurality of auxiliary grid lines;
[0010] Each pair of main grid lines comprises a first main grid line and a second main grid line arranged at intervals, and a conductive connecting piece is arranged between the first main grid line and the second main grid line on each pair of main grid lines.
[0011] In an optional embodiment, the plurality of pairs of main grid lines extend along a first direction, and the plurality of pairs of main grid lines are arranged in parallel;
[0012] The plurality of auxiliary grid lines extend along a second direction perpendicular to the first direction, and the plurality of auxiliary grid lines are arranged in parallel.
[0013] In an optional embodiment, the interval between the first main grid line and the second main grid line on each pair of main grid lines is 1.5mm-3mm.
[0014] In an optional embodiment, the interval between two adjacent auxiliary grid lines is 0.9mm-1.3mm, and the interval between two adjacent pairs of main grid lines is 10mm-12mm.
[0015] In an optional embodiment, each pair of main grid lines is provided with an end pad at both ends, and each end pad is provided with two pairs of fish-tail lines.
[0016] In an optional embodiment, each fish-tail line comprises a first fish-tail line segment and a second fish-tail line segment, the first fish-tail line segment and the second fish-tail line segment are arranged intermittently, and the extension direction of the first fish-tail line segment is the same as that of the main grid line.
[0017] The second fish-tail line segment extends obliquely outward, and the interval between the two second fish-tail line segments on each pair of fish-tail lines gradually increases from inside to outside.
[0018] In an optional embodiment, the distance along the second direction that the end pad extends is a width, the interval between the two pairs of fish-tail lines is greater than the width of the end pad, and the interval between the first main grid line and the second main grid line on each pair of main grid lines is greater than the width of the end pad.
[0019] In an optional embodiment, at least one intermediate pad is arranged between the first main grid line and the second main grid line on each pair of main grid lines.
[0020] In an optional embodiment, the conductive connecting piece is a solder strip.
[0021] In a second aspect, the utility model provides a photovoltaic module, comprising the solar cell of any one of preceding embodiments.
[0022] The beneficial effects of the solar cell and the photovoltaic module provided by the embodiment of the utility model include: a plurality of pairs of main grid lines are arranged, each pair of main grid lines comprises a first main grid line and a second main grid line which are arranged at intervals, and a conductive connecting piece (such as a solder strip) is arranged between the first main grid line and the second main grid line on each pair of main grid lines. The double-channel transmission mode provided by the utility model carries out double-connection line path conduction, and even if the fine grid is welded off due to too low height, the connection lines on both sides can collect the current in the solder strip passing area. At the same time, the solder strip welding left-right offset window is enlarged, the component rework rate can be reduced, a new current collection channel is opened, and the current transmission path is increased. BRIEF DESCRIPTION OF DRAWINGS
[0023] In order to more clearly illustrate the technical scheme of the embodiment of the utility model, the following will briefly introduce the drawings needed to be used in the embodiment, and it should be understood that the following drawings only show some embodiments of the utility model, and therefore should not be regarded as a limitation to the scope. For ordinary skilled in the art, other related drawings can also be obtained according to these drawings without creative labor.
[0024] Figure 1 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure.
[0025] Figure 2 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure. Figure 1 The enlarged view of the A area in the figure.
[0026] Figure 3 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure.
[0027] Figure 4 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure. Figure 3 The enlarged view of the B area in the figure.
[0028] Figure 5 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure. Figure 4 The schematic diagram of the fine grid appearing welding-off in the figure.
[0029] Figure 6 The structure schematic diagram of the solar cell provided for the embodiment is shown in the figure. Figure 5 The enlarged view of the C area in the figure.
[0030] Figure 7 The schematic diagram of the current transmission being blocked after welding-off in the figure.
[0031] Icon: 100-solar cell;110-grid electrode;111-main grid line;1111-first main grid line;1112-second main grid line;112-sub grid line;113-conductive connecting piece;121-end pad;132-fork line;1321-first fork line segment;1322-second fork line segment;123-intermediate pad;
[0032] 200 - solar cell; 201 - sub busbar; 202 - main busbar; 203 - solder strip. DETAILED DESCRIPTION
[0033] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.
[0034] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.
[0035] It should be noted that: similar reference numbers and letters represent similar items in the following drawings, therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.
[0036] In the description of the present application, it should be noted that if the terms "upper", "lower", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, which is only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.
[0037] In addition, if the terms "first", "second" and the like appear, they are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.
[0038] It should be noted that the features in the embodiments of the present application can be combined with each other without conflict.
[0039] In addition, in order to facilitate understanding, the professional terms involved in the embodiments of the present application are explained in detail in the following table:
[0040] Professional term 1: sub busbar line, used for collecting carriers generated in the solar cell;
[0041] Professional term 2: main busbar line, the main busbar line is connected with the sub busbar line, collects the carriers collected by each sub busbar, and bears the welding;
[0042] Professional term 3: centipede foot, as the lap joint design at the junction of the main and auxiliary grid, can make the welding strip left and right offset have fault tolerance space, and the area will increase the grid line height after superposition, meet the height required by component welding;
[0043] Professional term 4: harpoon line, the open design of the battery piece edge makes the welding strip also have offset allowance, and connects the edge grid line, prevents the current transmission from being blocked after the edge grid is broken;
[0044] Professional term 5: pad point, a silver base designed to provide welding tension on the main grid at intervals, which can replace the single main grid to meet the welding.
[0045] The overall structure, working principle and technical effects of the solar cell 100 are described in detail below through embodiments and in conjunction with the drawings.
[0046] Please refer to Figure 1 The utility model provides a kind of solar cell 100, including battery piece and grid line electrode 110, grid line electrode 110 is arranged on the surface of battery piece and forms ohmic contact with battery piece, and the generated carrier is collected by grid line electrode 110 and exports current.
[0047] Please combine Figure 1 And Figure 2 Grid line electrode 110 includes multiple pairs of main grid lines 111, multiple auxiliary grid lines 112 and multiple conductive connecting pieces 113, multiple pairs of main grid lines 111 are arranged at intervals, and each pair of main grid lines 111 is connected with multiple auxiliary grid lines 112, which can transport carriers to multiple pairs of main grid lines 111, and then the carriers on multiple pairs of main grid lines 111 export current. Each pair of main grid lines 111 includes first main grid line 1111 and second main grid line 1112 arranged at intervals, and one conductive connecting piece 113 is arranged between the first main grid line 1111 and the second main grid line 1112 of each pair of main grid lines 111.
[0048] In the prior art, the reduction of the height of the fine grid will cause the welding of the grid line to be broken by the silver-eating reaction, which will further cause poor transmission, and the root cause of this situation is that the transmission path is blocked, and the current of the fine grid cannot be transmitted to the main grid and the pad point. The silver-eating reaction is a chemical change under the thermal reaction of tin metal welding strip and silver material grid line, and the welding strip and grid line can be welded together through the reaction by 320-380℃ furnace irradiation, to ensure the transmission of current.
[0049] Therefore, the embodiment of the utility model discloses double channel transmission mode replaces the existing main grid design, carries out double connection line path conduction. Through setting up multiple pairs of main grid line 111, each pair of main grid line 111 includes the first main grid line 1111 and the second main grid line 1112 of interval setting, and the electrically conductive connecting piece 113 (such as solder strip) is set between the first main grid line 1111 and the second main grid line 1112 on each pair of main grid line. Multiple pairs of main grid line 111 form double channel transmission mode, carry out double connection line path conduction, even if the fine grid is welded off because the height is too low, the connecting line on both sides can collect the current of the solder strip passing area. At the same time, the main grid connecting line moves to the centipede foot end point of the original solder pad, and the solder strip welding left and right offset window expands, which can reduce the assembly rework rate, open a new current collection channel and increase the current transmission path.
[0050] In addition, the fine grid centipede foot on the solar cell 100 provided by the utility model is cancelled, the original centipede foot is not needed to pad the height of the solder strip, the amount of paste is saved, the light-shielding area is reduced, and the cost is reduced and the efficiency is improved.
[0051] Specifically, the preparation method of the main grid line 111 and the auxiliary grid line 112 is not limited, and can be formed by traditional silver paste printing. The specific process can refer to the preparation of the existing main grid and auxiliary grid.
[0052] In some embodiments, the multiple pairs of main grid lines 111 extend along a first direction (i.e. Figure 2 Y direction) and the multiple pairs of main grid lines 111 are arranged in parallel; and the multiple auxiliary grid lines 112 extend along a second direction (i.e. Figure 2 X direction) approximately perpendicular to the first direction, and the multiple auxiliary grid lines 112 are arranged in parallel. The parallel arrangement of the grid lines is easier to control during the preparation process and is convenient to operate. All the auxiliary grid lines 112 are approximately perpendicular to the main grid lines 111 (the main grid lines 111 can have a small angle inclination, such as 1°-3°), which is beneficial to reduce the transmission distance of the carriers and improve the output efficiency of the solar cell.
[0053] In some embodiments, the interval between the first main grid line 1111 and the second main grid line 1112 on each pair of main grid lines 111 is 1.5-3 mm, such as 1.5 mm, 2.0 mm, 2.5 mm, 3.0 mm, etc. The interval between two adjacent sub-grid lines 112 is 0.9-1.3 mm, such as 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, etc. The interval between two adjacent pairs of main grid lines 111 is 10-12 mm, such as 10 mm, 11 mm, 12 mm, etc. By adjusting the interval of each grid line in the grid line electrode 110, and thus adjusting the distribution of the grid lines, the photoelectric conversion efficiency can be improved. Specifically, the interval between two adjacent pairs of main grid lines 111 refers to the horizontal distance between the first main grid line 1111 and the second main grid line 1112 of the adjacent pair of first main grid lines 1111.
[0054] In some embodiments, at least one intermediate pad 123 is arranged between the first main grid line 1111 and the second main grid line 1112 on each pair of main grid lines 111. The end pads 121 are arranged at both ends of each pair of main grid lines 111, and two pairs of fish-tail lines 132 are arranged on each end pad 121. The fish-tail lines 132 arranged on the end pads 121 at both ends mainly have two functions: (1) they can prevent edge grid breakage, which can cause blackening phenomenon due to the failure to collect electrons; and (2) they can form an opening to allow the solder ribbon to have a deviation amount when passing through, and the fish-tail can collect edge electrons.
[0055] In preferred embodiments, each fish-tail line 132 includes a first fish-tail line segment 1321 and a second fish-tail line segment 1322, which are arranged discontinuously and connected to different positions of the sub-grid line 112. The first fish-tail line segment 1321 extends in the same direction as the main grid line 111, and the positions of the two first fish-tail line segments 1321 correspond to the positions of the first main grid line 1111 and the second main grid line 1112. The second fish-tail line segment 1322 extends obliquely outward, and the interval between the two second fish-tail line segments 1322 on each pair of fish-tail lines 132 gradually increases from the inside to the outside, approximately forming a horn shape. The segmented fish-tail line 132 can ensure the transmission of the current edge while the overall printing deviation can ensure the neatness in the appearance of the printing. In the preparation process, the fish-tail is formed by two separate printings, and is not the result of one printing, so it is not easy to produce printing deviation.
[0056] In some embodiments, the distance that the end pad 121 extends along the second direction is the width, the spacing between the two pairs of harpoon lines 132 is greater than the width of the end pad 121, and the spacing between the first main gate line 1111 and the second main gate line 1112 on each pair of main gate lines 111 is greater than the width of the end pad 121. By adjusting the size relationship between the harpoon lines 132, the main gate lines 111 and the end pad 121, a better buffering effect can be achieved, and the main gate lines are less likely to develop microcracks when soldered with the solder wire.
[0057] This utility model embodiment also provides a photovoltaic module, including the above-mentioned solar cell 100, multiple solar cells 100 forming a cell string, which is then encapsulated to form a photovoltaic module for photoelectric conversion in power plants and other scenarios.
[0058] Example 1
[0059] The structural diagram of the solar cell 100 provided in this embodiment is as follows: Figure 1 , Figure 2 As shown. The steps for designing the battery cell graphic are as follows:
[0060] (1) First, fix the solder strip (copper wire with tin-plated lead solder) on the battery cell by dispensing. The solder strips are set in parallel.
[0061] (2) Main grid lines 111 and sub-grid lines 112 are prepared by screen printing process. The main grid lines 111 are all along the first direction (i.e., Figure 2 Extending in the Y direction, and multiple pairs of main grid lines 111 are arranged in parallel; multiple sub-grid lines 112 are all along the second direction (i.e., Figure 2 Extending in the X direction, multiple sub-gate lines 112 are arranged in parallel. Between the first main gate line 1111 and the second main gate line 1112 on each pair of main gate lines 111. Each pair of main gate lines 111 has end pads 121 at both ends, and each end pad 121 has two pairs of harpoon lines 132.
[0062] The spacing between the first main gate line 1111 and the second main gate line 1112 on each pair of main gate lines 111 is 2.0 mm. The spacing between two adjacent sub-gate lines 112 is 1.1 mm, and the spacing between two adjacent pairs of main gate lines 111 is 11 mm.
[0063] Comparative Example 1
[0064] like Figure 3 and Figure 4 As shown, the solar cell 200 provided in this comparative example has a single-channel transmission mode for the main grid line, including a main grid 202, a sub-grid 201, and a solder strip 203. Except for the main grid 202, which differs from the structure of Example 1, the other structures and parameters are the same as in Example 1.
[0065] It should be noted that the single-channel transmission mode provided by Comparative Example 1 is designed to weld the solder tape to the pad of the main grid alone, but under the trend of low wet weight reduction, the disadvantages of the design gradually emerge, because the wet weight of the sub-grid is too low, the overall grid line of the sub-grid is very low, and the required height cannot be met in the centipede foot area, which will cause the grid line to be broken by the silver corrosion reaction during welding, as shown in Figure 5 and Figure 6 . Figure 7 The crossed-out part in the middle indicates that the current transmission in this area is blocked after the solder is broken, and the current in this area cannot be directly conducted from the main grid to the solder tape above. The current can only be transmitted through a longer path, the longer the path, the greater the series resistance, the more current loss, the greater the efficiency impact, and the lower the benefit of the battery piece. The present application adjusts the transmission path to transmit current from the main grid, so that the fine grid covered by the solder tape will not affect the overall transmission even if it is broken. Compared with Comparative Example 1, the main grid of Example 1 has the following advantages: (1) The centipede feet of the pad points are overlapped on both sides of the main grid, and the middle area is a window for soldering the solder tape. The soldering of the solder tape usually has a deviation, that is, the solder tape cannot be soldered on the main grid every time. In actual production, there is a deviation of 0.5mm left and right. The main grid of Example 1 is at both ends of the centipede foot, and the accuracy of the component end can be controlled under the condition of widening the range of qualified rate and reducing the loss of rework. (2) After the main grid is divided into two sides, the current is collected to the pad point through the two sides, and the middle solder tape area does not need the cushioning of the centipede foot, that is, the sub-grid centipede foot can be removed, and a larger part of the shading can be omitted. According to the calculation, the shading increase of the two-sided main grid is less than the shading of the omitted centipede foot, the total amount of light of the battery piece is increased, and the conversion efficiency of the battery piece can be increased. (3) The two-sided main grid collects current in multiple channels, which can effectively solve the problem that the sub-grid after the solder tape is broken cannot be collected, that is, the solder tape is collected from the two-sided main grid to the pad without the cushioning of the centipede foot.
[0066] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any skilled person in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A solar cell, characterized by, The solar cell includes a cell piece and a grid line electrode, the grid line electrode is arranged on the surface of the cell piece and forms ohmic contact with the cell piece; The grid line electrode includes a plurality of pairs of main grid lines, a plurality of sub-grid lines and a plurality of conductive connecting pieces, the pairs of main grid lines are arranged at intervals, and each pair of main grid lines is connected with the plurality of sub-grid lines; Each pair of main grid lines includes a first main grid line and a second main grid line arranged at intervals, and a conductive connecting piece is arranged between the first main grid line and the second main grid line of each pair of main grid lines.
2. The solar cell according to claim 1, characterized in that, The pairs of main grid lines extend along a first direction, and the pairs of main grid lines are arranged in parallel. The plurality of sub-grid lines extend along a second direction perpendicular to the first direction, and the plurality of sub-grid lines are arranged in parallel.
3. The solar cell according to claim 1 or 2, characterized in that, The interval between the first main grid line and the second main grid line of each pair of main grid lines is 1.5-3 mm.
4. The solar cell according to claim 3, characterized in that, The interval between adjacent two sub-grid lines is 0.9-1.3 mm, and the interval between adjacent two pairs of main grid lines is 10-12 mm.
5. The solar cell according to claim 2, characterized in that, Each pair of main grid lines is provided with an end pad at both ends, and each end pad is provided with two pairs of fish-tail lines.
6. The solar cell according to claim 5, characterized in that, Each fish-tail line includes a first fish-tail line segment and a second fish-tail line segment, the first fish-tail line segment and the second fish-tail line segment are arranged intermittently, and the extension direction of the first fish-tail line segment is the same as that of the main grid line. The second fish-tail line segment extends obliquely outward, and the interval between the two second fish-tail line segments of each pair of fish-tail lines gradually increases from inside to outside.
7. The solar cell according to claim 5, characterized in that, The distance of the end pad extending along the second direction is the width, the interval between the two pairs of fish-tail lines is greater than the width of the end pad, and the interval between the first main grid line and the second main grid line of each pair of main grid lines is greater than the width of the end pad.
8. The solar cell according to claim 5, characterized in that, At least one intermediate pad is arranged between the first main grid line and the second main grid line of each pair of main grid lines.
9. The solar cell according to claim 1, characterized in that, The conductive connecting piece is a solder strip.
10. A photovoltaic module, characterized by, The solar cell includes the solar cell according to any one of claims 1-9.