A photovoltaic module and a method of determining a number of cells of a photovoltaic module

Abstract

The application relates to a photovoltaic module and a method for determining the number of cell pieces of the photovoltaic module, and belongs to the technical field of photovoltaic technology.The photovoltaic module comprises a panel, a first adhesive film layer, a cell unit, a second adhesive film layer and a back plate which are sequentially stacked; the cell unit comprises two symmetrical and independently arranged cell piece arrays, and each cell piece array is independently provided with an outgoing end; each cell piece array comprises a cell string arranged along a first direction, and each cell string is formed by connecting b cell pieces along a second direction, the first direction and the second direction are perpendicular, and N=a*b is satisfied; wherein N is the total number of cell pieces of each cell piece array, a>=2, b>=a / 2, and a and b are both even numbers. The application can solve the problem of serious internal electrical mismatch loss of the existing photovoltaic module in the function of adapting to a micro inverter, and can significantly reduce the mismatch loss of voltage and current, improve the operation efficiency of the photovoltaic module and the economic competitiveness.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a photovoltaic module and a method for determining the number of cells in a photovoltaic module. Background Technology

[0002] With the development of photovoltaic technology, microinverters have been widely used due to their advantages such as achieving module-level maximum power point tracking (MPPT), improving system power generation efficiency, and simplifying system design. Third-generation high-power microinverters (GEN3) often adopt a "one-to-two" architecture, where one inverter has two independent MPPT channels, each connected to two physically isolated cell strings within a photovoltaic module. This architecture requires the module to be divided into two electrically independent subarrays (each channel), each meeting the inverter's input voltage and current parameter requirements.

[0003] In traditional implementations, photovoltaic modules generally adopt a universal and standardized design logic, with the number of cells typically being 132 or 144, and their series-parallel structure is mainly optimized for centralized inverters or string inverters. This means that there is only one circuit on a photovoltaic module, and the positive and negative terminals of different photovoltaic modules are connected in series.

[0004] However, since microinverters are typically configured as a 1-to-2 architecture, two independent circuits must be connected to adapt to this architecture. Traditionally, the solar cells are divided into two paths, for example, dividing 132 cells into two 66-cell paths, with each 66 cell typically allocated as 6×11. The number 11 is odd, and due to the lack of mirror symmetry in its topology, separating them into two independent external microinverters would lead to asymmetrical layout, crossed leads, and abnormal differences in short-circuit current and operating voltage between the two paths. This would cause severe internal electrical mismatch losses, reducing the overall efficiency of the photovoltaic module by 5%–10% and increasing the unit power generation cost by 8%–15%. Furthermore, asymmetrical wiring or uneven current distribution can cause some cells to remain in reverse bias for extended periods, significantly increasing the risk of hot spots and ultimately affecting the lifespan of the photovoltaic module.

[0005] Therefore, there is an urgent need for a photovoltaic module that can adapt to the functional requirements of micro-inverters to solve the technical problems mentioned above. Summary of the Invention

[0006] Based on this, this application provides a photovoltaic module and a method for determining the number of cells in the photovoltaic module. By configuring the cell units into two symmetrical and independent cell arrays, each cell array includes an even number of cell strings, and each cell string is composed of an even number of cells connected in series. This effectively solves the problems of asymmetrical layout, crossed leads, and abnormal short-circuit current and operating voltage differences between the two outputs in existing photovoltaic modules when adapting to micro-inverters, which lead to serious internal electrical mismatch losses. It achieves the effect of significantly reducing voltage and current mismatch losses in photovoltaic modules without increasing the cost of main materials and maintaining compatibility with existing mainstream production lines, thereby improving the operating efficiency and economic competitiveness of photovoltaic modules.

[0007] To address the above problems, firstly, a photovoltaic module is provided, comprising: The panel, the first adhesive layer, the battery cell, the second adhesive layer, and the backplate are stacked in sequence. The battery unit includes two symmetrical and independently arranged cell arrays, each with its own lead-out terminal; Each battery cell array includes a battery strings arranged along a first direction. Each battery string is composed of b battery cells connected in series along a second direction. The first and second directions are perpendicular to each other and satisfy N = a × b. Wherein, N is the total number of battery cells in each battery cell array, a ≥ 2, b ≥ a ÷ 2, and both a and b are even numbers.

[0008] An optional solution is that, under preset high temperature conditions, the open-circuit voltage of each cell array is less than or equal to the preset maximum allowable voltage, and the short-circuit current of each cell array is less than or equal to the preset maximum allowable current. Under preset low temperature conditions, the maximum power point voltage of each cell array is greater than or equal to the preset minimum operating voltage.

[0009] An alternative approach is to ensure that the spacing between two adjacent battery strings in each battery cell array is at least 2 mm. The spacing between two adjacent cells in each battery string is at least 1.5 mm; The distance between the battery string and the edge of the battery cell is greater than or equal to 12mm.

[0010] An alternative approach is to include a positive electrode lead and a negative electrode lead, with the positive and negative electrode leads distributed along the horizontal direction of the battery cell. The positive terminal is led out through the positive junction box located on the back panel, and the negative terminal is led out through the negative junction box located on the back panel.

[0011] An alternative is that the spacing between the positive and negative junction boxes along the horizontal direction of the battery cell is greater than or equal to 60% of the length of a single positive or negative junction box.

[0012] An alternative is that the backplate has a positive lead hole at the positive lead-out end and a negative lead hole at the negative lead-out end. The positive and negative lead holes are staggered along the vertical direction of the battery cell.

[0013] An alternative is to have the positive lead hole and the negative lead hole staggered by a distance greater than or equal to 8mm.

[0014] An alternative approach is to ensure that the difference in the total internal interconnect resistance between the two cell arrays is less than or equal to 1 mΩ, and... Under the preset standard test conditions, the ratio of the difference in short-circuit current between the two cell arrays to the short-circuit current of any one cell array is less than or equal to 3%; the ratio of the difference in operating voltage between the two cell arrays to the operating voltage of any one cell array is less than or equal to 3%.

[0015] Secondly, a method for determining the number of solar cells in a photovoltaic module as described above is provided, the method comprising: Obtain the electrical performance data of the solar cells, and determine the size of the solar cells based on the electrical performance data and the preset maximum operating point current value; wherein, the preset maximum operating point current value is the maximum operating point current value of each MPPT of the micro inverter. Based on the size values, determine the standard electrical parameter data of the solar cell and obtain the electrical parameter constraint data; Based on electrical parameter constraint data, preset standard temperature values, preset high temperature conditions, preset low temperature conditions, and standard electrical parameter data, the maximum allowable range of the number of solar cells for each solar cell array is obtained. Based on the preset rules and the arrangement of the photovoltaic module's cell array, values ​​to be determined are selected sequentially from the maximum allowable range of cell counts to obtain the values ​​to be verified. Based on preset standard temperature values, preset high temperature conditions, and preset low temperature conditions, the electrical performance of the cell array corresponding to the value to be verified is verified to obtain the target value. Based on the target value, the total number of cells N in the cell array, as well as the values ​​of a and b, are obtained.

[0016] An optional approach is to use electrical parameter constraint data including voltage window constraint range values ​​and maximum input current constraint values, and standard electrical parameter data including standard open-circuit voltage values, standard maximum power point voltage values, standard short-circuit current values, standard open-circuit voltage temperature coefficient values, standard maximum power point voltage temperature coefficient values, and standard short-circuit current temperature coefficient values. Based on the electrical parameter constraint data, preset standard temperature values, preset high-temperature conditions, preset low-temperature conditions, and standard electrical parameter data, the maximum allowable range of cell counts for each cell array is obtained, including: Based on the voltage window constraint range, preset standard temperature, preset high temperature conditions, standard maximum power point voltage, and standard maximum power point voltage temperature coefficient, the minimum value among the ranges of the maximum allowable number of solar cells in the solar cell array is obtained. Based on the voltage window constraint range, preset standard temperature, preset low temperature conditions, standard open circuit voltage, and standard open circuit voltage temperature coefficient, the maximum value among the ranges of the maximum allowable number of solar cells in the solar cell array is obtained. Based on the maximum input current constraint value, preset standard temperature value, preset high temperature condition, standard short-circuit current value, standard short-circuit current temperature coefficient value, and preset standard component maximum value, the maximum and minimum values ​​are adjusted to obtain the maximum allowable range of the number of solar cells in the solar cell array.

[0017] Beneficial effects: By configuring the battery cells into symmetrical and independent dual-channel arrays, each channel array includes an even number of cell strings, and each cell string consists of an even number of cells connected in series, this effectively solves the problems of asymmetrical layout, crossed leads, and abnormal short-circuit current and operating voltage differences between the two output channels in existing photovoltaic modules when adapting to micro-inverters. These issues lead to severe internal electrical mismatch losses. The solution achieves significant reductions in voltage and current mismatch losses in photovoltaic modules, improving their operating efficiency and economic competitiveness, requiring only an update to the photovoltaic module layout and junction box assembly process without the need for additional equipment or molds. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of a photovoltaic module in one embodiment; Figure 2 This is a schematic diagram of the battery cell arrangement in a photovoltaic module according to one embodiment; Figure 3 This is a schematic diagram of a partial location of the backsheet in a photovoltaic module according to one embodiment.

[0019] Reference numerals: 1. Photovoltaic module; 11. Panel; 12. First encapsulant layer; 13. Cell unit; 131. Cell array; 1311. Cell string; 1312. Cell; 14. Second encapsulant layer; 15. Backsheet; 151. Positive junction box; 152. Negative junction box; 153. Positive lead hole; 154. Negative lead hole. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0021] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0022] The structures, proportions, sizes, etc., shown in the accompanying drawings are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the implementation conditions of this application. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0023] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "lateral," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the purpose of simplifying the description. They 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, and therefore should not be construed as limiting this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0024] In existing technologies, photovoltaic (PV) modules generally adopt a universal and standardized design logic, with typically 132 or 144 cells, and their series-parallel structures are primarily optimized for centralized or string inverters. This means that only one circuit exists on each PV module, and the positive and negative terminals of different PV modules are connected in series. However, since microinverters are typically a 1-to-2 architecture, two independent circuits must be connected to adapt to this architecture. Traditionally, the cells are divided into two circuits; for example, 132 cells are divided into two 66-cell circuits, and the 66-cell circuits are generally further allocated as 6×11. The number 11 is odd, and due to the lack of mirror symmetry in its topology, if it is separated and used as two independent external micro-inverters, it will lead to asymmetrical layout, crossed leads, and abnormal differences in short-circuit current and operating voltage between the two outputs. This will cause serious internal electrical mismatch losses, reducing the overall efficiency of the photovoltaic module by 5%–10% and increasing the unit power generation cost by 8%–15%. At the same time, asymmetrical wiring or uneven current will cause some cells to be in a reverse bias state for a long time, significantly increasing the risk of hot spots and affecting the lifespan of the photovoltaic module. Therefore, this application provides a photovoltaic module that, by arranging the cells in the battery unit, can significantly reduce voltage and current mismatch losses of the photovoltaic module without adding new equipment or molds, requiring only an update to the layout of the photovoltaic module and the assembly process of the junction box. This improves the operating efficiency and economic competitiveness of the photovoltaic module.

[0025] Example 1 The following detailed description of a photovoltaic module provided in this embodiment, with reference to the accompanying drawings, is provided in detail. Figure 1 , Figure 2 As shown, it includes: a panel 11, a first adhesive film layer 12, a battery unit 13, a second adhesive film layer 14, and a backplate 15 stacked sequentially; the battery unit 13 includes two symmetrically and independently arranged battery cell arrays 131, each battery cell array 131 having a separate lead-out terminal; each battery cell array 131 includes a battery strings 1311 arranged along a first direction, each battery string 1311 being formed by b battery cells 1312 connected in series along a second direction, the first direction and the second direction being perpendicular to each other, and satisfying N = a×b; where N is the total number of battery cells 1312 in each battery cell array 131, a≥2, b≥a÷2, and a and b are both even numbers.

[0026] like Figure 1As shown, the photovoltaic module 1 includes a panel 11, a first encapsulating film layer 12, a battery cell 13, a second encapsulating film layer 14, and a backsheet 15 stacked sequentially from top to bottom. The panel 11 can be made of tempered glass, the first encapsulating film layer 12 and the second encapsulating film layer 14 can both be made of EVA (ethylene-vinyl acetate) and POE (polyolefin elastomer) composite encapsulating film, and the backsheet 15 can be made of PET (polyethylene terephthalate) and encapsulated with an aluminum frame.

[0027] Specifically, such as Figure 1 , Figure 2 As shown, the battery unit 13 includes two electrically isolated cell arrays 131. The two cell arrays 131 are mirror-symmetrical at 180° along the central axis of the photovoltaic module 1 in the horizontal direction. Each cell array 131 has an individual lead-out terminal. Each cell array 131 includes a cell strings 1311 arranged along a first direction. Each cell string 1311 is composed of b cells 1312 connected in series along a second direction. The first and second directions are perpendicular to each other. The first direction can be horizontal, and the second direction can be vertical, satisfying N = a × b. Here, N is the total number of cells 1312 in each cell array 131. Therefore, the total number of cells 1312 in the photovoltaic module 1 is 2N. At the same time, it is also necessary to satisfy the conditions that a ≥ 2, b ≥ a ÷ 2, and a and b are both even numbers.

[0028] It should be noted that the constraint "b≥a÷2, where a and b are both even numbers" has a clear engineering purpose and physical significance: First, requiring "a" to be even ensures that the number of parallel battery strings 1311 in each battery array 131 is even. This allows the start and end points of all battery strings 1311 to naturally converge on the same side of the battery array 131, laying the foundation for achieving complete mirror symmetry of the layout and the same-side arrangement of leads, thereby avoiding the problems of lead crossing and path asymmetry caused by the traditional odd-numbered string layout. Second, requiring "b" to be even ensures that each battery string 1311 is composed of an even number of battery cells 1312 connected in series. This helps to achieve a more balanced current distribution and thermal management at the battery cell 1312 level, significantly reducing the risk of more severe hot spots caused by uneven voltage distribution and excessive local power dissipation, and improving the long-term reliability of the photovoltaic module 1. Finally, the ratio "b ≥ a ÷ 2" itself is an optimization of the topology of the cell array 131. It constrains the ratio of the number of series cells to the number of parallel cells 1312, preventing the series resistance from being too large due to the excessive length of a single cell string 1311, and also avoiding the problem of excessive parallel strings leading to a complex internal current collection network.

[0029] Preferably, N can be 64, and both a and b can be 8. It should be noted that the type, quantity, connection order, and interconnection ribbon path length of the cells 1312 in the two-channel cell array 131 are completely identical. In addition, the cells 1312 in the cell array 131 of this application can be N-type TOPCon half-cell cells. The N-type TOPCon half-cell cell is divided into two by laser cutting, but it is definitely not 1 / 2. Its size also determines the current magnitude. That is, it is not simply a change in shape, but more importantly, it changes the current path and magnitude, reconstructing the internal circuit topology of the photovoltaic module 1. Specifically, 1) it can reduce internal resistance loss: the path of current movement within the cell is halved, and the internal resistance loss is reduced to 1 / 4 of the original, which helps to improve the conversion efficiency of photovoltaic module 1 by 0.2%-0.5%; 2) it can improve the hot spot effect: the smaller cell size means less heat is generated when partially shaded, reducing the risk of hot spots and lowering the hot spot temperature by 15-20℃, making photovoltaic module 1 safer and more reliable; 3) it can reduce the impact of shading: the half-cell design reduces the sensitivity of the module to shading when it is installed horizontally or vertically, resulting in less power generation loss under shading; 4) it has a better appearance: the gaps between the cells of photovoltaic module 1 are finer in appearance.

[0030] The above operation, by setting the battery unit 13 as two symmetrical and independent battery cell arrays 131, each battery cell array 131 includes an even number of battery strings 1311 and each battery string is composed of an even number of battery cells 1312 connected in series, can effectively solve the problems of asymmetrical layout, crossed leads, abnormal short-circuit current and operating voltage differences between the two outputs in the existing photovoltaic module 1 when adapting to the micro-inverter function, which lead to serious internal electrical mismatch losses. It achieves the effect of significantly reducing the voltage and current mismatch losses of the photovoltaic module 1 and improving the operating efficiency and economic competitiveness of the photovoltaic module 1 without adding new equipment or molds, only requiring an update to the layout of the photovoltaic module 1 and the junction box assembly process.

[0031] Preferred, refer to Figure 1 , Figure 2 As shown, under preset high temperature conditions, the open-circuit voltage of each cell array 131 is less than or equal to the preset maximum allowable voltage, and the short-circuit current of each cell array 131 is less than or equal to the preset maximum allowable current; under preset low temperature conditions, the maximum power point voltage of each cell array 131 is greater than or equal to the preset minimum operating voltage.

[0032] The open-circuit voltage can be represented by Voc; the short-circuit current by Isc; and the maximum power point voltage by Vmp. The preset high-temperature condition can be set to 75°C; the preset low-temperature condition can be set to -10°C; the preset maximum allowable voltage can be set to 60V; the preset maximum allowable current can be set to 16A; and the preset minimum operating voltage can be set to 16V. It should be noted that the settings for the preset maximum allowable voltage, preset maximum allowable current, and preset minimum operating voltage are primarily based on the electrical parameters of the micro-inverter itself, and these settings allow for better compatibility with the micro-inverter.

[0033] Specifically, such as Figure 1 As shown, each photovoltaic module 1 can be individually connected to a microinverter, and microinverters have special electrical requirements, namely a narrow MPPT (Maximum Power Point Tracking) and a low maximum input current. Furthermore, the open-circuit voltage and operating voltage of the photovoltaic module 1 are significantly affected by temperature. Existing technology may cause the operating voltage of the photovoltaic module 1 to fall below the lower limit of the microinverter's MPPT during high summer temperatures; and during low winter temperatures, the open-circuit voltage may approach or even exceed the upper limit of the microinverter's withstand voltage, resulting in the photovoltaic module being unable to operate efficiently for approximately 10%–15% of the year. Therefore, this application requires constraints on the open-circuit voltage, short-circuit current, and maximum power point voltage of each cell array 131.

[0034] Specifically, such as Figure 2 As shown, at 75°C, the open-circuit voltage of each cell array 131 is less than or equal to 60V, i.e., Voc<=60, and the short-circuit current of each cell array 131 is less than or equal to 16A, i.e., Isc<=16; at -10°C, the maximum power point voltage of each cell array 131 is greater than or equal to 16V, i.e., Vmp>=16.

[0035] The above operations, by constraining the open-circuit voltage, short-circuit current, and maximum power point voltage of each cell array 131, make the arrangement and number of cells 1312 in each cell array 131 more in line with the requirements, thereby extending the efficient operating time within the MPPT window, reducing internal mismatch losses, and increasing annual power generation.

[0036] Preferred, refer to Figure 1 , Figure 2 As shown, the spacing between two adjacent battery strings 1311 in each battery cell array 131 is at least 2 mm; the spacing between two adjacent battery cells 1312 in each battery string 1311 is at least 1.5 mm; and the margin between the battery string 1311 and the edge of the battery cell 13 is greater than or equal to 12 mm.

[0037] Specifically, such as Figure 1 , Figure 2 As shown, the string spacing between two adjacent battery strings 1311 in each battery cell array 131 is at least 2 mm. Here, since each battery cell array 131 is composed of multiple battery cells 1312 connected in series, the operating voltage may be as high as tens of volts. Therefore, if the spacing between two adjacent battery strings 1311 is too small, creepage or air breakdown may occur in high humidity and polluted environments, leading to short circuits or leakage faults. The 2 mm spacing is a safe distance to ensure air insulation and meet safety regulations (such as IEC 61215).

[0038] The spacing between any two adjacent cells 1312 in each cell string 1311 must be at least 1.5 mm. This is because the cells 1312 (especially silicon wafers) are very brittle. During lamination, the EVA (encapsulating film) melts and flows under pressure. If the spacing between the cells 1312 is too small, the flowing EVA will generate huge, uneven shear stress on the edges of adjacent cells 1312, easily leading to microcracks in the cells 1312. Therefore, a 1.5 mm gap provides a channel for EVA flow, evenly distributing the pressure.

[0039] The battery string 1311 has a clearance of 12mm or more from the edge of the battery cell 13. This is because the edge of the battery cell 13 is the weakest point of the seal and the area with the highest stress concentration. If the battery string 1311 is too close to the edge, the sealing pressure at the edge during lamination may be insufficient, leading to delamination. Moisture can then penetrate from this point, corroding the internal circuitry and causing the battery cell 13 to fail. The 12mm clearance provides sufficient overlap area of ​​the encapsulation material at the edge of the battery cell 13 to ensure a secure seal.

[0040] The above operations, by setting the spacing of the battery strings 1311, the spacing of the battery cells 1312, and the edge margin in the battery cell array 131, achieve the effect of improving the yield and consistency of photovoltaic module 1 production and ensuring long-term reliable operation.

[0041] Preferred, refer to Figure 1 , Figure 3 As shown, the lead-out terminals include a positive lead-out terminal and a negative lead-out terminal, which are distributed along the horizontal direction of the battery cell 13; the positive lead-out terminal is led out through the positive junction box 151 provided on the back plate 15, and the negative lead-out terminal is led out through the negative junction box 152 provided on the back plate 15.

[0042] Specifically, such as Figure 1 , Figure 3As shown, each cell array 131 is individually provided with a lead-out terminal, and each lead-out terminal includes a positive lead-out terminal and a negative lead-out terminal, which are distributed along the horizontal direction of the cell 13. The positive lead-out terminal is led out through the positive junction box 151 provided on the back plate 15, and the negative lead-out terminal is led out through the negative junction box 152 provided on the back plate 15.

[0043] It should be noted that the two positive leads of the two-channel battery cell array 131 are symmetrical about the central axis of the vertical direction of the battery cell 13, and the two negative leads of the two-channel battery cell array 131 are symmetrical about the central axis of the vertical direction of the battery cell 13.

[0044] In the above operation, because in a traditional centralized layout, the current generated by the cell string 1311 on one side of the photovoltaic module 1 must flow through a long internal busbar to reach the junction box on the other side, the resistance of this path will cause significant power loss. However, the method of setting a separate lead for each cell 1312 in this application can greatly reduce internal power loss and improve power generation efficiency.

[0045] Preferred, refer to Figure 1 , Figure 3 As shown, the distance between the positive junction box 151 and the negative junction box 152 along the horizontal direction of the battery cell 13 is greater than or equal to 60% of the length of a single positive junction box 151 or negative junction box 152.

[0046] Among them, the positive junction box 151 is the junction box with the positive lead-out terminal installed, and the negative junction box 151 is the junction box with the negative lead-out terminal installed.

[0047] Specifically, such as Figure 1 , Figure 3 As shown, the spacing between the positive junction box 151 and the negative junction box 152 corresponding to each battery cell array 131 along the horizontal direction of the battery cell 13 is greater than or equal to 60% of the length of a single positive junction box 151 or negative junction box 152.

[0048] The above operation, by limiting the spacing between the positive junction box 151 and the negative junction box 152 corresponding to each solar cell array 131 along the horizontal direction of the photovoltaic module 1, achieves the effects of enhancing electrical safety, maximizing thermal isolation, preventing thermal coupling effects, and improving maintainability and fault diagnosis convenience.

[0049] Preferred, refer to Figure 1 , Figure 3 As shown, the back plate 15 has a positive lead hole 153 at the positive lead end and a negative lead hole 154 at the negative lead end; the positive lead hole 153 and the negative lead hole 154 are staggered along the vertical direction of the battery cell 13.

[0050] Specifically, such as Figure 1 , Figure 3 As shown, the back plate 15 has a positive lead hole 153 at the positive lead end and a negative lead hole 154 at the negative lead end; at the same time, the positive lead hole 153 and the negative lead hole 154 are staggered along the vertical direction of the battery cell 13.

[0051] In one feasible manner, the offset distance between the positive lead hole 153 and the negative lead hole 154 is greater than or equal to 8 mm.

[0052] Specifically, the offset distance between the positive lead hole 153 and the negative lead hole 154 is greater than or equal to 8mm.

[0053] The above operation sets the positive lead hole 153 and the negative lead hole 154 to be staggered along the vertical direction of the battery cell 13, and the staggered distance is greater than or equal to 8mm, that is, through physical isolation, the effect of preventing short circuit is achieved.

[0054] Preferred, refer to Figure 1 , Figure 2 As shown, the difference in the total internal interconnection resistance between the two battery cell arrays 131 is less than or equal to 1mΩ, and under the preset standard test conditions, the ratio of the difference in short-circuit current between the two battery cell arrays 131 to the short-circuit current of any one channel is less than or equal to 3%; the ratio of the difference in operating voltage between the two battery cell arrays 131 to the operating voltage of any one channel is less than or equal to 3%.

[0055] The preset standard test conditions refer to light conditions at 25℃.

[0056] Specifically, such as Figure 1 , Figure 2 As shown, the total internal interconnection resistance between each cell array 131 can be tested using the four-wire resistance test method. The difference in the total interconnection resistance value between different channels is less than or equal to 1mΩ.

[0057] Simultaneously, the short-circuit current and operating voltage of each cell array 131 can be measured. The ratio of the difference in short-circuit current between two cell arrays 131 to any single short-circuit current value is less than or equal to 3%. Assuming the short-circuit currents between the two cell arrays 131 are 9.5A and 9.75A respectively, the difference is 0.25A. Ratios of 0.25A to 9.5A and 9.75A respectively yield 0.25 / 9.5, which is approximately 2.63%, less than 3%. Similarly, 0.25 / 9.75 is approximately 2.56%, less than 3%, thus meeting the limiting condition. The ratio of the difference in operating voltage between two cell arrays 131 to any single operating voltage value is also less than or equal to 3%. The calculation principle is similar to the short-circuit current limit mentioned above and will not be repeated here.

[0058] The above operations, by limiting the difference between the total internal interconnection resistance between the two cell arrays 131, achieve the effects of maximizing power output, ensuring long-term reliability, and suppressing hot spot effects; by limiting the ratio of the difference in short-circuit current between the two cell arrays 131 to the short-circuit current of any one cell array, and the ratio of the difference in operating voltage to the operating voltage of any one operating voltage, the minimum output power of the photovoltaic module 1 is guaranteed, and on-site inspection is facilitated.

[0059] Example 2 The following describes in detail, with reference to the accompanying drawings, a method for determining the number of solar cells in the aforementioned photovoltaic module. Please refer to the accompanying drawings. Figure 1 , Figure 2 As shown, the process includes: acquiring electrical performance data of the solar cell 1312; determining the size of the solar cell 1312 based on the electrical performance data and a preset maximum operating point current value; determining the standard electrical parameter data of the solar cell 1312 based on the size value, and acquiring electrical parameter constraint data; obtaining the maximum allowable range of the number of solar cells 1312 in each solar cell array 131 based on the electrical parameter constraint data, preset standard temperature value, preset high temperature condition, preset low temperature condition, and standard electrical parameter data; selecting undetermined values ​​sequentially from the maximum allowable range of the number of solar cells 1312 according to preset rules and the arrangement of the solar cell array 131 of the photovoltaic module 1, to obtain the value to be verified; verifying the electrical performance of the solar cell array 131 corresponding to the value to be verified based on the preset standard temperature value, preset high temperature condition, and preset low temperature condition, to obtain the target value; and obtaining the total number N of solar cells 1312 in the solar cell array 131, as well as the values ​​of a and b, based on the target value.

[0060] The preset maximum operating point current value is the maximum operating point current value for each MPPT (Maximum Power Point Tracking) of the microinverter. Electrical performance data includes, but is not limited to, the type and efficiency of the 1312 solar cells.

[0061] The electrical parameter constraint data is for a configuration with two DC input channels, supporting a 1-to-2 architecture. Specifically, it includes voltage window constraint range values, i.e., the voltage window range for each DC input channel; and maximum input current constraint values. Standard electrical parameter data includes open-circuit voltage values, which can be obtained using STC. Voc The maximum power point voltage value can be represented by STC. Vmp The short-circuit current value can be represented by STC. Isc The open-circuit voltage temperature coefficient can be represented by γ. Voc The temperature coefficient of the maximum power point voltage can be represented by β. Vmp The temperature coefficient of short-circuit current can be represented by α. Isc express.

[0062] Specifically, the electrical performance data of the solar cell 1312 is obtained, and the size of the solar cell 1312 is determined based on the electrical performance data and the preset maximum operating point current value. In this application, the solar cells 1312 within the solar cell array 131 can be selected from mainstream N-type TOPCon half-cell cells. After determining this type, the size of the solar cell 1312 can be calculated and determined based on the battery efficiency parameters provided by the manufacturer. That is, the maximum operating point current of each MPPT of the micro-inverter is used as a benchmark, combined with the battery efficiency parameters (i.e., the maximum operating point current) of the original solar cell 1312 for matching and selection. The specific principles are as follows: If the maximum operating point current of the solar cell 1312 is less than or much less than the maximum operating point current of the micro inverter MPPT, then the solar cell 1312 shall not be adopted. If the maximum operating point current of the solar cell 1312 is greater than the maximum operating point current of the micro inverter MPPT, then the required size of the solar cell 1312 to be cut is calculated and determined according to the ratio of the two currents, thus obtaining the size of the solar cell 1312.

[0063] Based on the dimensions, the standard electrical parameter data of the solar cell 1312 is determined, and the electrical parameter constraint data is obtained. After determining the dimensions of the solar cell 1312, the standard electrical parameter data of the solar cell 1312 can then be obtained.

[0064] like Figure 1 , Figure 2As shown, since the dimensions of the solar cells 1312 within the solar cell array 131 are already determined, the corresponding standard electrical parameter data under standard conditions, i.e., under illumination conditions with a preset standard temperature of 25°C, can be directly obtained. Specifically, the standard open-circuit voltage value STC... Voc 0.735 V; Standard Maximum Power Point Voltage (STC) Vmp 0.64V; Standard short-circuit current value STC Isc The standard open-circuit voltage temperature coefficient value γ is 6.9A. Voc The standard maximum power point voltage temperature coefficient β is -0.0032 °C. Vmp The temperature coefficient of the standard short-circuit current is -0.0036 °C and α is the standard short-circuit current temperature coefficient. Isc It is 0.05% / °C.

[0065] Meanwhile, the electrical parameter constraints for cell 1312 can be obtained from the datasheet of "GEN3 Microinverter 2-in-1 (600W-1000W)", namely, a voltage window constraint range of 16-60V and a maximum input current constraint of 16A. It should be noted that in the 1-to-2 architecture, each photovoltaic module 1 is internally divided into two cell arrays 131, each connected to one of the two DC input ports of the microinverter. Therefore, the Voc of each cell array 131 is ≤ 60V, and Vmp ∈ [16, 60]V.

[0066] Based on electrical parameter constraint data, preset standard temperature values, preset high-temperature conditions, preset low-temperature conditions, and standard electrical parameter data, the maximum allowable range of 1312 cells per cell array 131 is obtained. In one feasible approach, the minimum value within the maximum allowable range of 1312 cells is obtained based on the voltage window constraint range, preset standard temperature values, preset high-temperature conditions, standard maximum power point voltage values, and standard maximum power point voltage temperature coefficient values; the maximum value within the maximum allowable range of 1312 cells is obtained based on the voltage window constraint range, preset standard temperature values, preset low-temperature conditions, standard open-circuit voltage values, and standard open-circuit voltage temperature coefficient values; and the maximum and minimum values ​​are adjusted based on the maximum input current constraint values, preset standard temperature values, preset high-temperature conditions, standard short-circuit current values, standard short-circuit current temperature coefficient values, and preset standard component maximum values ​​to obtain the maximum allowable range of 1312 cells.

[0067] Specifically, based on the voltage window constraint range, preset standard temperature, preset high temperature conditions, standard maximum power point voltage, and standard maximum power point voltage temperature coefficient, the minimum value among the maximum allowable ranges for the number of solar cells 1312 is obtained. That is, under the preset high temperature conditions, i.e., 75°C, Vmp ≥ 16 V must be satisfied. Specifically, the expression for the maximum power point voltage Vmp of a single solar cell 1312 in the solar cell array 131 at this time is as follows: Vmp=STC Vmp ×[1+β Vmp [×(75-25)]=0.640×[1+(-0.0036)×(75-25)]; = 0.5248 V; The expression for the minimum value in the maximum permissible range of 1312 battery cells is as follows: N min ×0.5248≥16 → N min ≈ 30; Based on the voltage window constraint range, preset standard temperature, preset low temperature conditions, standard open-circuit voltage, and standard open-circuit voltage temperature coefficient, the maximum value of the maximum allowable range of solar cell 1312 is obtained. That is, under the preset low temperature conditions, i.e., -10°C, Voc ≤ 60V must be satisfied. Specifically, the expression for the standard open-circuit voltage Voc of a single solar cell 1312 in the solar cell array 131 at this time is as follows: Voc=STC Voc ×[1+γ Voc [×(-10-25)]; =0.735×[1+(-0.0032×(-10-25))]; =0.8173 V; The expression for the maximum value of the maximum allowable range of 1312 battery cells is as follows: N max ×0.817≤60 → N max ≈73; Therefore, the maximum allowable range of 1312 solar cells is [31, 73].

[0068] Based on the maximum input current constraint value, preset standard temperature value, preset high temperature condition, standard short-circuit current value, standard short-circuit current temperature coefficient value, and preset standard component maximum value, the maximum and minimum values ​​are adjusted to obtain the maximum allowable range of the number of solar cells 1312. Specifically, under the preset high temperature condition, i.e., +75°C, Isc < 16A ​​must be satisfied. The expression for the input current value Isc of a single solar cell 1312 in the solar cell array 131 at this time is as follows: Isc= STCIsc × (1+ α Isc ×(75-25)); =6.90 × (1 + 0.0005 × (75 - 25)); ≈ 7.07 A < 16 A → Satisfied; Under the given conditions, no adjustment is needed to the maximum and minimum values. However, since the maximum number of commonly used cells 2N for photovoltaic module 1 is 144 half cells, i.e., N ≤ 72, the maximum allowable cell range of 1312 obtained above is finely adjusted to [31, 73] to obtain the final maximum allowable cell range of 1312 [31, 72].

[0069] According to the preset rules and the arrangement of the cell array 131 of the photovoltaic module 1, the values ​​to be determined are selected sequentially from the range of the maximum allowable number of cells 1312 in the cell array 131 to obtain the values ​​to be verified.

[0070] The preset rule refers to selecting according to the rule of decreasing by 8 from largest to smallest.

[0071] Specifically, following the rule of decreasing by 8 sequentially from largest to smallest and the arrangement of the solar cell array 131 of photovoltaic module 1, undetermined values ​​are selected sequentially from the range of the maximum allowable number of solar cells 1312. That is, under the premise of the maximum allowable range of the number of solar cells 1312 of solar cell array 131 [31, 72], following the rule of decreasing by 8 sequentially from largest to smallest and the arrangement of the solar cell array 131 of photovoltaic module 1, the largest integer N ≤ 72 is found such that N = a × b, and a≥2, b≥a÷2, where a and b are both even numbers. That is, starting from the maximum value of 72, 72 is decomposed into 72 = 8 × 9 → b = 8 (even number), a = 9 (odd number), which obviously does not meet the requirements. Continuing the search from largest to smallest and subtracting 8 from each, we find N = 72 - 8 = 64. We can decompose 64 into 64 = 8 × 8 → b = 8 (even number), a = 8 (even number), and 8 ≥ 8 ÷ 2, which satisfies the condition. Therefore, we determine N = 64 as the value to be verified.

[0072] Based on the preset standard temperature value, preset high temperature condition, and preset low temperature condition, the electrical performance of the cell array 131 corresponding to the value to be verified is verified to obtain the target value.

[0073] The electrical performance includes the standard open-circuit voltage Voc of the cell array 131 and the range of the standard maximum power point voltage Vmp of the cell array 131.

[0074] Specifically, the verification is conducted under preset standard test conditions (25℃), preset high temperature conditions (75℃), and preset low temperature conditions (-10℃) to determine whether the standard open-circuit voltage Voc of the cell array 131 corresponding to the value to be verified is less than or equal to 60 V, and whether the standard maximum power point voltage Vmp of the cell array 131 is within the range of [16, 60].

[0075] Specifically, under the preset standard test conditions, i.e., 25℃, the expression for the standard open-circuit voltage Voc of the cell array 131 corresponding to the value to be verified is as follows: Voc=N×STC Voc ×[1+γ Voc [×(25-25)]; =64×0.735×[1+(-0.0032×0)]; =24V≤60; The expression for the standard maximum power point voltage Vmp of the cell array 131 corresponding to the value to be verified is as follows: Vmp = N×STC Vmp ×[1+β Vmp [×(25-25)]; =64×0.640×[1+(-0.0036×0)]; =40.96V in the range [16,60]; Under the preset high-temperature condition of 75℃, the expression for the standard open-circuit voltage Voc of the cell array 131 corresponding to the value to be verified is as follows: Voc=N×STC Voc ×[1+γ Voc [×(75-25)]; =64×0.735×[1+(-0.0032×50)]; =39.51V≤60; The expression for the standard maximum power point voltage Vmp of the cell array 131 corresponding to the value to be verified is as follows: Vmp = N×STC Vmp ×[1+β Vmp [×(75-25)]; =64×0.640×[1+(-0.0036×50)]; =33.58V in the range [16,60]; Under the preset low-temperature condition (-10℃), the expression for the standard open-circuit voltage Voc of the cell array 131 corresponding to the value to be verified is as follows: Voc=N×STC Voc ×[1+γVoc [×(-10-25)]; =64×0.735×[1+(-0.0032×(-35))]; =52.31V≤60; The expression for the standard maximum power point voltage Vmp of the cell array 131 corresponding to the value to be verified is as follows: Vmp = N×STC Vmp ×[1+β Vmp [×(-10-25)]; =64×0.640×[1+(-0.0036×(-35))]; =46.12V in the range [16,60]; As calculated above, under the preset standard test conditions of 25℃, the preset high temperature condition of 75℃, and the preset low temperature condition of -10℃, the standard open-circuit voltage Voc of the cell array 131 corresponding to the value to be verified is less than or equal to 60 V, and the standard maximum power point voltage Vmp of the cell array 131 is within the range of [16, 60]. Therefore, the value to be verified, 64, is the target value.

[0076] Based on the target value, the total number N of solar cells 1312 in the solar cell array 131, as well as the values ​​of a and b, are obtained.

[0077] Specifically, after obtaining 64, it means that the number N of each cell array 131 is 64, the total number of cells in the entire photovoltaic module 1 is 128 half cells, and the series-parallel structure is: 8 substrings × 8 cells per channel.

[0078] It should be noted that this application document, by adjusting the arrangement of photovoltaic module 1 and the junction box assembly process, is compatible with existing lamination and stringing equipment, and has been verified to have the following advantages: 1) Its operating power is approximately 490 Wp, and the electrical mismatch of the two-channel cell array 131 is ≤ 2.5%.

[0079] 2) The annual power generation of photovoltaic module 1 increases by 5%–12%, and the LCOE decreases by 8%–15% to enhance economic competitiveness. The power generation per unit area increases by about 15%, saving rooftop resources.

[0080] 3) Under preset standard test conditions, the mismatch between the two currents can be reduced from 5-8% in the traditional solution to less than 1.5%, and the risk of hot spots is reduced by about 40%.

[0081] 4) The yield rate of mass production can reach 99.2%, which is on par with traditional photovoltaic modules.

[0082] 5) The symmetrical wiring setup increases BOM cost by less than 0.5%.

[0083] 6) For a production line with an annual output of 1GW, the payback period for the upgrade investment is less than 6 months.

[0084] That is, the settings of this application enable the photovoltaic module 1 to operate safely and efficiently across the entire temperature range.

[0085] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0086] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A photovoltaic module, characterized in that, include: The panel (11), the first adhesive film layer (12), the battery cell (13), the second adhesive film layer (14), and the back plate (15) are stacked in sequence. The battery unit (13) includes two symmetrically and independently arranged battery cell arrays (131), each of which has a lead-out terminal. Each of the battery cell arrays (131) includes a battery strings (1311) arranged along a first direction. Each battery string (1311) is composed of b battery cells (1312) connected in series along a second direction. The first direction and the second direction are perpendicular to each other and satisfy N = a × b. Wherein, N is the total number of battery cells (1312) in each battery cell array (131), a ≥ 2, b ≥ a ÷ 2, and a and b are both even numbers.

2. The photovoltaic module according to claim 1, characterized in that, Under preset high temperature conditions, the open-circuit voltage of each of the battery cell arrays (131) is less than or equal to the preset maximum allowable voltage, and the short-circuit current of each of the battery cell arrays (131) is less than or equal to the preset maximum allowable current. Under preset low temperature conditions, the maximum power point voltage of each of the battery cell arrays (131) is greater than or equal to the preset minimum operating voltage.

3. The photovoltaic module according to claim 1, characterized in that, The spacing between two adjacent battery strings (1311) in each of the battery cell arrays (131) is at least 2 mm; The spacing between two adjacent battery cells (1312) in each battery string (1311) is at least 1.5 mm; The distance between the battery string (1311) and the edge of the battery cell (13) is greater than or equal to 12 mm.

4. The photovoltaic module according to claim 1, characterized in that, The lead-out terminals include a positive lead-out terminal and a negative lead-out terminal, which are distributed along the horizontal direction of the battery cell (13); The positive terminal is led out through the positive junction box (151) provided on the back plate (15), and the negative terminal is led out through the negative junction box (152) provided on the back plate (15).

5. The photovoltaic module according to claim 4, characterized in that, The distance between the positive junction box (151) and the negative junction box (152) along the horizontal direction of the battery cell (13) is greater than or equal to 60% of the length of a single positive junction box (151) or negative junction box (152).

6. The photovoltaic module according to claim 4, characterized in that, The back plate (15) is provided with a positive lead hole (153) at the positive lead end and a negative lead hole (154) at the negative lead end. The positive electrode lead hole (153) and the negative electrode lead hole (154) are staggered along the vertical direction of the battery cell (13).

7. The photovoltaic module according to claim 6, characterized in that, The offset distance between the positive lead hole (153) and the negative lead hole (154) is greater than or equal to 8 mm.

8. The photovoltaic module according to claim 1, characterized in that, The difference in the total internal interconnect resistance between the two cell arrays (131) is less than or equal to 1 mΩ; and, Under the preset standard test conditions, the ratio of the difference in short-circuit current between the two battery cell arrays (131) to the short-circuit current of any one of them is less than or equal to 3%, and the ratio of the difference in operating voltage between the two battery cell arrays (131) to the operating voltage of any one of them is less than or equal to 3%.

9. A method for determining the number of solar cells in a photovoltaic module as described in any one of claims 1-8, characterized in that, The method includes: Obtain the electrical performance data of the battery cell (1312), and determine the size value of the battery cell (1312) based on the electrical performance data and the preset maximum operating point current value; wherein, the preset maximum operating point current value is the maximum operating point current value of each MPPT of the micro inverter. Based on the stated dimensions, the standard electrical parameter data of the battery cell (1312) is determined, and the electrical parameter constraint data is obtained. Based on the electrical parameter constraint data, preset standard temperature value, preset high temperature condition, preset low temperature condition and the standard electrical parameter data, the maximum allowable range of the number of battery cells (1312) for each battery cell array (131) is obtained; According to the preset rules and the arrangement of the cell array (131) of the photovoltaic module (1), the values ​​to be determined are selected sequentially from the range of the maximum allowable number of cells (1312) to obtain the values ​​to be verified. Based on the preset standard temperature value, the preset high temperature condition, and the preset low temperature condition, the electrical performance of the cell array (131) corresponding to the value to be verified is verified to obtain the target value, and based on the target value, the total number N of the cell array (1312) N of the cell array (131) and the values ​​of a and b are obtained.

10. The method according to claim 9, characterized in that, The electrical parameter constraint data includes voltage window constraint range values ​​and maximum input current constraint values. The standard electrical parameter data includes standard open-circuit voltage values, standard maximum power point voltage values, standard short-circuit current values, standard open-circuit voltage temperature coefficient values, standard maximum power point voltage temperature coefficient values, and standard short-circuit current temperature coefficient values. The step of obtaining the maximum allowable range of the number of solar cells (1312) for each solar cell array (131) based on the electrical parameter constraint data, preset standard temperature values, preset high-temperature conditions, preset low-temperature conditions, and the standard electrical parameter data includes: Based on the voltage window constraint range value, the preset standard temperature value, the preset high temperature condition, the standard maximum power point voltage value, and the standard maximum power point voltage temperature coefficient value, the minimum value among the range values ​​of the maximum allowable number of solar cells (1312) is obtained; Based on the voltage window constraint range value, the preset standard temperature value, the preset low temperature condition, the standard open circuit voltage value, and the standard open circuit voltage temperature coefficient value, the maximum value among the range values ​​of the maximum allowable number of solar cells (1312) is obtained. Based on the maximum input current constraint value, the preset standard temperature value, the preset high temperature condition, the standard short-circuit current value, the standard short-circuit current temperature coefficient value, and the preset standard component maximum value, the maximum value and the minimum value are adjusted to obtain the maximum allowable range of battery cells (1312).

Images