A back contact cell, cell string, cell module
By alternating semiconductor regions of different polarities on the back surface of the back contact solar cells and setting up an extended area, and by using fine grid lines and main grid lines to cross-connect and an intermediate busbar, the problems of large gaps and poor busbar effect of the back contact solar cells are solved, thereby improving the efficiency and aesthetics of the module.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- GOLD STONE (FUJIAN) ENERGY CO LTD
- Filing Date
- 2025-07-23
- Publication Date
- 2026-06-16
Smart Images
Figure CN224368232U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of back contact battery technology, and in particular to a back contact battery cell, battery string, and battery assembly. Background Technology
[0002] A back-contact battery is a type of battery in which both the emitter and base contact electrodes are placed on the back of the battery. The light-receiving surface of this battery is not obstructed by any metal electrodes, which effectively increases the short-circuit current of the battery cells. At the same time, the back can accommodate wider metal grid lines to reduce series resistance and thus improve the fill factor. Furthermore, this type of battery with no obstruction on the front not only has high conversion efficiency but also looks more aesthetically pleasing.
[0003] For conventional back-contact solar cells, the cells are interconnected via solder ribbons. Due to limitations in module packaging technology, a 1-2mm gap needs to be maintained between adjacent cells to prevent short circuits and damage. This reduces the actual area of the cells within the module, thus lowering the module's efficiency. Furthermore, current is only collected between cells via solder ribbons, and finally integrated via busbars, resulting in generally poor current collection efficiency.
[0004] It should be noted that this content only provides background technology related to this utility model, and does not necessarily constitute prior art or publicly known technology. Utility Model Content
[0005] The purpose of this invention is to provide a back-contact battery cell, battery string, and battery module that, by setting an extended area, increasing the intermediate busbar, and using a secondary busbar, increases the battery cell's current collection capacity, reduces the gap between battery cells, and indirectly improves the module's conversion efficiency.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] This utility model discloses a back-contact battery cell, which includes a battery cell body with a PN junction layer structure. The back surface of the battery cell body has several first semiconductor regions and second semiconductor regions with different polarities alternately distributed along the Y-axis direction. Corresponding first and second fine grid lines are provided on the first and second semiconductor regions.
[0008] The main body of the battery cell has a first semiconductor expansion region on one side along the Y-axis, and two or more first fine grid lines are provided on the first semiconductor expansion region; a second semiconductor expansion region is provided on the other side, and two or more second fine grid lines are provided on the second semiconductor expansion region; the width of the first semiconductor expansion region or the second semiconductor expansion region is 0.5-3mm.
[0009] The backlight surface of the battery cell body is provided with a plurality of paired first main grid lines and second main grid lines along the X-axis direction; the first main grid lines are respectively connected to a plurality of first fine grid lines on the battery cell and are insulated from the second fine grid lines; the second main grid lines are respectively connected to a plurality of second fine grid lines on the battery cell and are insulated from the first fine grid lines.
[0010] Furthermore, the first main grid line is connected to the first fine grid line of the first semiconductor widening region and the first semiconductor region respectively. A second insulating block is provided at the intersection of the first main grid line and the second fine grid line to insulate the second fine grid line and connect the first fine grid line on the cell in series. The second main grid line is connected to the second fine grid line of the second semiconductor widening region and the second semiconductor region respectively. A first insulating block is provided at the intersection of the second main grid line and the first fine grid line to insulate the first fine grid line and connect the second fine grid line on the cell in series.
[0011] Furthermore, the main body of the battery cell is provided with a passivation layer, an anti-reflection layer, an N-type silicon wafer, a PN junction semiconductor layer, and a conductive film layer in sequence from the light-receiving surface to the back-light-receiving surface. The conductive film layer is provided with insulating grooves between semiconductor layers of different polarities to provide insulation.
[0012] This utility model also discloses a back-contact battery string, characterized in that it includes:
[0013] A plurality of battery cells, wherein the battery cells are the back contact battery cells described above;
[0014] The first solder strip is bonded and connected to the first main grid on the battery cell;
[0015] The second solder strip is bonded and connected to the second main grid on the solar cell;
[0016] An intermediate busbar is disposed between two adjacent battery cells; one side of the intermediate busbar is attached to and connected to the first fine grid line of the first semiconductor widening region of the battery cell and is connected to the first solder ribbon; the other side is attached to and connected to the second fine grid line of the second semiconductor widening region of another battery cell and is connected to the second solder ribbon.
[0017] Furthermore, the width of the intermediate busbar is 2mm-6mm and the thickness is <0.2mm.
[0018] Furthermore, the spacing between adjacent battery cells is 0.5mm-1.0mm.
[0019] Furthermore, the materials of the first solder strip, the second solder strip, and the intermediate busbar are low-temperature materials with a melting point below 150°C, and the coating adopts any one or more combinations of tin-lead-bismuth material layer, tin-lead-bismuth-silver material layer, tin-bismuth-silver material layer, and tin-lead material layer.
[0020] This utility model also discloses a back contact battery assembly, which includes the aforementioned back contact battery string.
[0021] The advantages of this utility model are:
[0022] This invention widens the PN region on both sides of the conventional back-contact battery along the Y-axis, so that each side forms a different battery polarity. Based on the conventional back-contact battery current collection, thin busbars are introduced into adjacent cells for current guidance. This allows the current to be collected from the fine grid to the main grid, and then collected again to the edge fine grid, enhancing the cell's current collection capability. Furthermore, by adding intermediate busbars and superimposed solder strips to the module package, the gap is reduced from 1-2mm in the prior art to 0.5mm-1.0mm, greatly reducing the gap between cells, increasing the area ratio of cells in the module package, and improving the module's conversion efficiency. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this utility model and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 This is a schematic diagram of the structure of the back contact battery cell in this embodiment.
[0025] Figure 2 This is a diagram showing the parallel arrangement of the back-contact solar cells.
[0026] Figure 3 This is a schematic diagram of the structure after the middle busbar is welded to the back contact battery cell.
[0027] Figure 4 This is a schematic diagram (a) of the battery string after welding the solder strips.
[0028] Figure 5 This is a schematic diagram (II) of the battery string after welding the solder strips.
[0029] Explanation of key component symbols:
[0030] 1. Fine gate line at the P-terminal; 2. Fine gate line at the N-terminal; 3. Widened region of the P-terminal semiconductor; 4. Widened region of the N-terminal semiconductor;
[0031] 5. P-pole main busbar; 6. N-pole main busbar; 7. N-pole insulating block; 8. P-pole insulating block; 9. P-pole solder strip; 10. N-pole solder strip; 11. Intermediate busbar. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0033] In this utility model, unless otherwise stated, directional terms such as "up," "down," "left," and "right" are generally understood in conjunction with the accompanying drawings and the directions shown in actual applications.
[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.
[0035] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0036] The endpoints and any values of the ranges disclosed herein are not limited to the precise ranges or values, and should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of the various ranges, the endpoint values of the various ranges and individual point values, and individual point values can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. The terms "optional" and "discretionary" mean that they may or may not be included (or may or may not be present).
[0037] like Figure 1As shown, this utility model discloses a back-contact solar cell, which includes a solar cell body with a PN junction layer structure. The back surface of the solar cell body has several alternating first semiconductor regions and second semiconductor regions of different polarities distributed along the Y-axis. In this embodiment, the first semiconductor region is a P-type semiconductor region, and the second semiconductor region is an N-type semiconductor region. Corresponding P-type fine grid lines and N-type fine grid lines are provided on the P-type and N-type semiconductor regions.
[0038] Specifically, in this embodiment, a P-type semiconductor extension region is provided on one side of the main body of the solar cell along the Y-axis, and two or more P-type fine gate lines are provided on the P-type semiconductor extension region; an N-type semiconductor extension region is provided on the other side, and two or more N-type fine gate lines are provided on the N-type semiconductor extension region. The width of the P-type semiconductor extension region or the N-type semiconductor extension region is 0.5-3mm, wherein the width of the P-type semiconductor extension region is greater than that of the N-type semiconductor extension region. The number of fine gate lines is also proportional to the width of the semiconductor extension region.
[0039] The back surface of the solar cell has several pairs of P-type main grid lines and N-type main grid lines arranged along the X-axis. The P-type main grid lines are connected to several fine P-type grid lines on the solar cell and are insulated from the fine N-type grid lines. Similarly, the N-type main grid lines are connected to several fine N-type grid lines on the solar cell and are insulated from the fine P-type grid lines. The grid lines and main grid lines are arranged in a finger-like, intersecting structure.
[0040] Specifically, the P-type main grid line is connected to the P-type fine grid line in both the P-type semiconductor widening region and the P-type semiconductor region. An N-type insulating block is placed at the intersection of the P-type main grid line and the N-type fine grid line to insulate the N-type fine grid line while simultaneously connecting the P-type fine grid lines on the solar cell in series. Similarly, the N-type main grid line is connected to the N-type fine grid line in both the N-type semiconductor widening region and the N-type semiconductor region. A P-type insulating block is placed at the intersection of the N-type main grid line and the P-type fine grid line to insulate the P-type fine grid line while simultaneously connecting the N-type fine grid lines on the solar cell in series.
[0041] The main body of the solar cell is provided with a passivation layer, an anti-reflection layer, an N-type silicon wafer, a PN junction semiconductor layer, and a conductive film layer in sequence from the light-receiving surface to the back-lighting surface. The conductive film layer is provided with insulating grooves between semiconductor layers of different polarities to provide insulation.
[0042] like Figures 2 to 5 As shown, this embodiment also discloses a back contact battery string, which includes: a plurality of battery cells, a P-type solder strip, an N-type solder strip, and an intermediate busbar.
[0043] The battery cell is the back contact battery cell mentioned above.
[0044] The P-electrode solder strip is bonded and connected to the P-electrode main grid on the solar cell.
[0045] The N-electrode solder strip is bonded and connected to the N-electrode main busbar on the solar cell.
[0046] The intermediate busbar is positioned between two adjacent solar cells. One side of the intermediate busbar is bonded to the fine grid lines of the P-polar semiconductor widening region of the solar cell and connected to the P-polar solder ribbon; the other side is bonded to the fine grid lines of the N-polar semiconductor widening region of the other solar cell and connected to the N-polar solder ribbon.
[0047] The central busbar is located below the solder ribbon and is attached to the solar cell, meaning it sits between the solder ribbon and the solar cell. Since the solder ribbon that contacts the solar cell is on the back side, this design allows the central busbar to cover the solder ribbon when the battery strings are assembled into a module, making it invisible from the front of the module. The color of the central busbar is similar to that of the solar cell, thus achieving a full-screen visual effect.
[0048] The width of the intermediate busbar is 2mm-6mm, and the thickness is <0.2mm. The spacing between adjacent cells is 0.5mm-1.0mm. The materials for the P-electrode solder strip, N-electrode solder strip, and intermediate busbar are low-temperature materials with a melting point below 150℃. The coating uses any one or more combinations of tin-lead-bismuth material layers, tin-lead-bismuth-silver material layers, tin-bismuth-silver material layers, and tin-lead material layers to facilitate solder strip welding.
[0049] like Figures 1 to 5 As shown, the method for manufacturing the above-mentioned back contact battery string includes the following steps:
[0050] Printed fine gate lines: P-type fine gate lines are printed along the Y-axis on the P-type semiconductor region and the P-type semiconductor extended region, and N-type fine gate lines are printed along the Y-axis on the N-type semiconductor region and the N-type semiconductor extended region.
[0051] Printed insulating blocks: Several P-pole insulating blocks are printed on the P-pole fine grid lines, and several N-pole insulating blocks are printed on the N-pole fine grid lines.
[0052] Printed main grid lines: Print the P-pole main grid lines along the X-axis direction of the P-pole fine grid lines and the N-pole insulating block, and print the N-pole main grid lines along the X-axis direction of the N-pole fine grid lines and the P-pole insulating block.
[0053] Welding intermediate busbars: Several solar cells are laid out in parallel with a gap of 0.5mm-1.0mm. Intermediate busbars are welded between two adjacent solar cells. One side of the intermediate busbar is bonded to the fine grid lines and main grid lines of the P-polar semiconductor extension region of the solar cell, and the other side is bonded to the fine grid lines and main grid lines of the N-polar semiconductor extension region of another solar cell.
[0054] Solder strip welding: Solder the P-pole solder strip onto the P-pole main bus line and the intermediate busbar connected to it, and solder the N-pole solder strip onto the second main bus line and the intermediate busbar connected to it. For example... Figure 4 As shown, in this embodiment, the two solder strips on the same X-axis of two adjacent solar cells have the same polarity. Therefore, two adjacent solar cells are connected to the intermediate busbar by two solder strips that are staggered. This allows for solder strip series connection by arranging the cells in parallel without cutting the entire cell, avoiding the cutting process and the risk of damage during cutting.
[0055] The position of the cell insulation block can also be changed so that the polarities of the two solder strips on the same X-axis of two adjacent cells are opposite. This allows the same solder strip to connect the main grids of two adjacent cells with different polarities to the intermediate busbar. Figure 5 As shown. This method can greatly simplify the efficiency of welding strips.
[0056] This embodiment also discloses a back contact battery assembly, which includes the aforementioned back contact battery string.
[0057] The preferred embodiments of this utility model have been described in detail above; however, this utility model is not limited thereto. Within the scope of the technical concept of this utility model, various simple modifications can be made to the technical solution of this utility model, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed by this utility model and are all within the protection scope of this utility model.
Claims
1. A back-contact solar cell, comprising a solar cell body having a PN junction layer structure, wherein a plurality of first semiconductor regions and second semiconductor regions of different polarities are alternately distributed on the back surface of the solar cell body along the Y-axis direction; and corresponding first and second fine grid lines are disposed on the first and second semiconductor regions. Its features are: The main body of the battery cell has a first semiconductor expansion region on one side along the Y-axis, and two or more first fine grid lines are provided on the first semiconductor expansion region; a second semiconductor expansion region is provided on the other side, and two or more second fine grid lines are provided on the second semiconductor expansion region; the width of the first semiconductor expansion region or the second semiconductor expansion region is 0.5-3mm. The backlight surface of the battery cell body is provided with a plurality of paired first main grid lines and second main grid lines along the X-axis direction; the first main grid lines are respectively connected to a plurality of first fine grid lines on the battery cell and are insulated from the second fine grid lines; the second main grid lines are respectively connected to a plurality of second fine grid lines on the battery cell and are insulated from the first fine grid lines.
2. The back contact battery cell according to claim 1, characterized in that: The first main grid line is connected to the first fine grid line of the first semiconductor expansion region and the first semiconductor region respectively. A second insulating block is provided at the intersection of the first main grid line and the second fine grid line to insulate the second fine grid line and connect the first fine grid line on the cell in series. The second main grid line is connected to the second fine grid line of the second semiconductor expansion region and the second semiconductor region respectively. A first insulating block is provided at the intersection of the second main grid line and the first fine grid line to insulate the first fine grid line and connect the second fine grid line on the cell in series.
3. The back contact battery cell according to claim 1, characterized in that: The main body of the battery cell is provided with a passivation layer, an anti-reflection layer, an N-type silicon wafer, a PN junction semiconductor layer, and a conductive film layer in sequence from the light-receiving surface to the back-lighting surface. The conductive film layer is provided with insulating grooves between semiconductor layers of different polarities to provide insulation.
4. A back-contact battery string, characterized in that: include: A plurality of battery cells, wherein the battery cells are back contact battery cells as described in any one of claims 1 to 3; The first solder strip is bonded and connected to the first main grid on the battery cell; The second solder strip is bonded and connected to the second main busbar on the solar cell. An intermediate busbar is disposed between two adjacent battery cells; one side of the intermediate busbar is attached to and connected to the first fine grid line of the first semiconductor widening region of the battery cell and is connected to the first solder ribbon; the other side is attached to and connected to the second fine grid line of the second semiconductor widening region of another battery cell and is connected to the second solder ribbon.
5. The back contact battery string according to claim 4, characterized in that: The width of the intermediate busbar is 2mm-6mm and the thickness is <0.2mm. The intermediate busbar is located between the solder strip and the battery cell.
6. The back contact battery string according to claim 4, characterized in that: The spacing between adjacent battery cells is 0.5mm-1.0mm.
7. The back contact battery string according to claim 4, characterized in that: The materials of the first solder strip, the second solder strip, and the intermediate busbar are low-temperature materials with a melting point below 150°C, and the coating adopts any one or more combinations of tin-lead-bismuth material layer, tin-lead-bismuth-silver material layer, tin-bismuth-silver material layer, and tin-lead material layer.
8. A back-contact battery assembly, characterized in that: Includes the back contact battery string as described in any one of claims 4 to 7.