Solar module arrangement method and four-series rectangular cell arrangement structure

Abstract

The application provides a solar module arrangement method and a four-string rectangular cell arrangement structure. The arrangement can achieve better performance and balance. The structure is symmetrical in upper and lower parts, each part has two strings of cells, the start and end points of the four strings are arranged on two sides, and the four strings are wrapped from the inside to the outside. The middle part of the inner string and the outer string is a single string turning arrangement mode. In addition, two side columns are arranged to cover the inner string, the number of cell pieces of each string is equal, the width of the string n is w n , the height of the string n is r n , the width of the outer string (n+1) is w n+1 =w n +2, the height of the two side columns is r n+1 , the number of two strings is equal, r n+1 ·w n+1 =r n ·(w n ‑2), and a recursive formula r n+1 =r n ·(w n ‑2) / (w n +2) is obtained. Since w n is an even number and at least 4, it is assumed that the w1 of the innermost string is 4, and w n =2·(n+1) is obtained. It is assumed that the module array has x rows and y columns, according to Σr=x / 2, the w n of the outermost string is y, and the corresponding r value is solved.

Description

Technical Field

[0001] This invention relates to the technical field of solar cell module layout design methods, specifically to a solar cell module layout method and a four-string rectangular cell layout structure. Background Technology

[0002] Due to the characteristics of photovoltaic cells, the larger the light-receiving area, the greater the current. However, the voltage of a single-junction cell is generally only on the order of 0.5 to 1V. Therefore, single-junction cells must be connected in series to output power. Before 2013, the circuit structure of mainstream commercial crystalline silicon modules was simply all cells connected in series, with the current entering from one end and meandering in an S-shape to the other end. Driven by the pursuit of production capacity, the silicon wafers used in the photovoltaic industry have become increasingly larger. To improve the collection efficiency of photocurrent over a large area, i.e., to reduce series resistance and thus increase module power, the electrode wiring structure of the cells has continuously evolved, with grid lines becoming thinner and denser, and the number of main grid lines increasing from 2 or 3 to more than 10. Later, it was discovered that if the cell area is reduced, for example, by cutting the cell in half, the current path is shorter over the smaller area, resulting in higher collection efficiency, i.e., a smaller series resistance per unit area. Therefore, re-optimizing the electrodes over a smaller area can both increase module power and reduce the number of grid lines, achieving both efficiency improvement and cost reduction. This led to the development of cell slicing technology, with half-sliced ​​cells (two-cell modules) becoming the mainstream module configuration, along with six-cell shingled technology. For N-cell modules, if simply strung together, the voltage would become N times the original, and the current would become 1 / N of the original. To maintain downstream compatibility and reduce the impact of shading, N-cell modules are generally connected in parallel in N strings, maintaining operating voltage and current essentially the same as the original single-string module.

[0003] The planar layout design of a two-segment battery module is relatively simple. It mirrors the original single-string circuit layout, sharing the middle busbar, and outputting power from both positive and negative ends, achieving highly efficient space utilization. Figure 1 As shown, A represents the original single-string arrangement, and the arrows indicate the direction of current (the number of rows is for example).

[0004] Using 3-cell, 4-cell, 5-cell, 6-cell, etc., module performance can be further improved. However, if compatibility of operating current and voltage specifications must still be maintained, then modules with N-cell cells must use N strings of the same number of cells connected in parallel. When N>2, how to lay these cell strings on a plane to achieve the best performance, or to achieve the best balance, is an urgent problem to be solved.

[0005] For rectangular (or quasi-rectangular with chamfers, not discussed further) solar cells, matrix arrangement is the most natural and space-efficient layout. Based on this, to reduce series resistance, the use of busbars should be minimized. In a single-string module, the most suitable arrangement is a straight string, with busbars only at the start and end points. While this achieves maximum module output power, such a narrow, elongated shape is clearly inconvenient for production and use. Therefore, the cell strings are laid out in a meandering, rectangular pattern, with busbars connecting the bends, while also accommodating the arrangement of bypass diodes (such as...). Figure 1 The dashed frame has become a traditional design element.

[0006] When multiple strings are connected in parallel, reducing the number of turning busbars becomes an option because the parallel strings can be arranged in parallel to expand the width. For example, a component of 6 strings can be designed as 6 straight strings arranged in parallel. Although longer busbars are needed at the start and end points, the overall benefit is greater because the intermediate turning busbars are completely eliminated. If turning in the middle of the strings is still necessary due to insufficient width or other reasons, then the length of the busbars at the start and end points should be reduced to make the start and end points of each string as close as possible. If the limit is one turning point, an example of an even number of strings arranged in parallel that conforms to this principle is as follows: Figure 2 and Figure 3 The examples (row numbers are for illustrative purposes) show strings of 4 and 6 respectively. The arrangement of odd-numbered strings can be obtained by taking half the arrangement of even-numbered strings; for example, the arrangement of a string of 3 can be obtained by... Figure 3 The upper half is obtained.

[0007] from Figure 2 and Figure 3 The comparison shows that: Figure 3 Although it can support a 6-string arrangement, the bus length is not the shortest; like Figure 2 By placing the start and end points at the centers of the four closest adjacent solar cells, the shortest possible bus length between the start and end points is achieved while still supporting a larger number of cells in series. Therefore, using four cells in parallel to form a module is ideal. However, with current solar cell sizes, a four-column module is considered a low-power configuration. If a higher-power module is to be made using four cells without wanting a narrow, elongated shape, the number of columns must be increased, meaning the number of bends must also be increased. If in... Figure 2Adding further bends and horizontal expansion requires the number of module columns to be a multiple of 4; otherwise, the endpoints of the upper and lower battery strings cannot reconnect, necessitating the use of long busbars to wind them back. However, the mainstream large-format design uses 6 columns, and expanding to 8 columns introduces more upstream and downstream compatibility issues. If the module width must remain at 6 columns, besides using long busbars as described above, authorized patent CN217881541U and pending patent CN119092578A both use a essentially similar method: adding an extra vertical long busbar in the middle to wind out first, then using two columns of parallel battery strings to wind back to the endpoint. This method is not only uneconomical but also increases series resistance, reducing the potential module power. Summary of the Invention

[0008] To address the shortcomings of existing technologies that cannot achieve good performance or a good balance when photovoltaic modules containing N strings of the same number of rectangular solar cells are laid out on a plane with N>2, this invention provides a solar module arrangement method. This invention also provides a four-string rectangular solar cell arrangement structure formed by the solar module arrangement method, which effectively solves this problem.

[0009] The solar module arrangement method is as follows: when the number of battery strings N≥4 and N is even, the modules are divided into two symmetrical blocks, one above the other. Each block has N / 2 battery strings. The start and end points of the strings are arranged on both sides, wrapping each other from the inside out. The innermost string is a single string with a turning arrangement. The middle part of all the outer strings is also a single string with a turning arrangement. Two side columns are added to wrap the strings inside. The number of cells in each string is equal.

[0010] Let the width of string n be w. n Let the height of string n be r. n Then the width of its outermost string (n+1) is w. n+1 = w n + 2, height is r n+1 Since the number of pieces in the two sequences is equal, we can obtain r. n+1 ·w n+1 =r n · (w n - 2), i.e., r n+1 = r n ·(w n - 2) / (w n +2), because w n It is an even number and at least 4. Assuming the innermost string w1=4, it is easy to obtain w n = 2 · (n+1), and the recurrence relation can be obtained sequentially:

[0011] r2 = r1 · 2 / 6

[0012] r3 = r1 · 2 · 4 / (6 · 8)

[0013] r4 = r1·2·4·6 / (6·8·10)

[0014] ...

[0015] r n = r1·2 / [n ·(n+1)]

[0016] Suppose the component array has x rows and y columns. According to Σr = x / 2, the outermost string w n = y, which can solve for the corresponding r value under various conditions, thus obtaining the specific arrangement; where: N: represents the number of battery strings; n: represents the serial number; w: string width, in terms of the number of battery cells; r: string height (excluding the outermost two side columns), in terms of the number of battery cells; x: module length, in terms of the number of battery cells; y: module width, in terms of the number of battery cells;

[0017] When N is odd, you can take the upper or lower half of the arrangement of 2N strings.

[0018] This method can also be used when N is 2, that is, take the upper or lower half of the arrangement where N is 4.

[0019] Thus, this invention provides a new arrangement of two or more (including two) rectangular solar cells. This design can be laid out on a plane to achieve better performance or a better balance.

[0020] The solar module arrangement method forms a four-string rectangular cell arrangement structure, which is divided into two symmetrical parts, each with two strings of cells. The start and end points of these four strings are arranged on both sides, wrapping around each other from the inside out. The inner string is a single string with a turning arrangement; the middle part of the outer string is also a single string with a turning arrangement, plus two side columns, forming a "gate" shape that wraps around the inner string. Since the output voltage of each string must be consistent, the number of cells in each string is equal.

[0021] For the two battery strings in the upper half, y = w2 = w1 + 2, r2 = r1·(w1 - 2) / (w1 + 2) = r1·(y - 4) / y.

[0022] Then, based on r2 + r1 = x / 2, we can solve for r1 = x / 4·y / (y-2) and r2 = x / 4·(y-4) / (y-2).

[0023] Since r2 > 0, y > 4. Also, y must be even; otherwise, the endpoints of the upper and lower battery strings wouldn't converge. Therefore, y must be at least 6. This arrangement of components requires at least 6 columns, which perfectly satisfies the width of the current large-format design. After determining y, we can obtain x based on the total number of battery cells in the component = x·y, and then obtain r. Because r must be an integer, the number of rows x cannot be arbitrarily chosen.

[0024] The advantages of this arrangement are: 1. The starting and ending points of the battery string converge at the center of the four most adjacent battery cells, resulting in the shortest convergence length; 2. There are fewer restrictions on the width of the module layout, requiring only an even number of columns of 6 or more, which can meet the needs of mainstream module sizes. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the mainstream 2-string 6-column component layout;

[0026] Figure 2 This is a schematic diagram of a 4-string, 4-column component with each string arranged in parallel.

[0027] Figure 3 This is a schematic diagram of a 6-string, 6-column component with each string arranged in parallel.

[0028] Figure 4 This is a schematic diagram of the arrangement of the four components of the present invention;

[0029] Figure 5 This is an example of a 4-string component 60-page layout using the present invention;

[0030] Figure 6 This is a schematic diagram of the arrangement of the three components of the present invention. Detailed Implementation

[0031] This invention provides a method for arranging solar modules. When the number of battery strings N≥4 and N is even, the modules are divided into two symmetrical sections, each with N / 2 battery strings. The starting and ending points of these strings are arranged on both sides, wrapping around each other from the inside out. The innermost string is arranged in a single-string turning pattern. The middle part of all the outer strings is also arranged in a single-string turning pattern, plus two side columns, forming a "gate" shape that encloses the strings inside. Since the output voltage of each string must be consistent, the number of cells in each string is equal.

[0032] Without loss of generality, when the number of battery strings N≥4 and N is even, the batteries are divided into two symmetrical sections, each with N / 2 battery strings. The start and end points of the strings are arranged on both sides, wrapping each other from the inside out. The innermost string is a single string with a turning arrangement. The middle part of all the outer strings is also a single string with a turning arrangement, plus two side columns to wrap the strings inside. The number of cells in each string is equal.

[0033] Let the width of string n be w. n Let the height of string n be r. n Then the width of its outermost string (n+1) is w. n+1 = w n + 2, height is r n+1 Since the number of pieces in the two sequences is equal, we can obtain r. n+1 ·w n+1 =r n · (wn - 2), i.e., r n+1 = r n ·(w n - 2) / (w n +2), because w n It is an even number and at least 4. Assuming the innermost string w1=4, it is easy to obtain w n = 2 · (n+1), and the recurrence relation can be obtained sequentially:

[0034] r2 = r1 · 2 / 6

[0035] r3 = r1 · 2 · 4 / (6 · 8)

[0036] r4 = r1·2·4·6 / (6·8·10)

[0037] ...

[0038] r n = r1·2 / [n ·(n+1)]

[0039] Suppose the component array has x rows and y columns. According to Σr = x / 2, the outermost string w n = y, which can solve for the corresponding r value under various conditions, thus obtaining the specific arrangement; where: N: represents the number of battery strings; n: represents the sequence number; w: string width, in terms of the number of battery cells; r: string height (excluding the outermost two side columns), in terms of the number of battery cells; x: module length, in terms of the number of battery cells;

[0040] y: Module width, in terms of the number of solar cells;

[0041] When N is odd, you can take either the upper or lower half of the 2N string arrangement; for example... Figure 6 As shown, Figure 6 It is a 3-string arrangement, and also the upper half of a 6-string distribution;

[0042] This method can also be used when N is 2, that is, taking the upper or lower half of the arrangement where N is 4. Figure 4 The upper or lower half of the text;

[0043] As mentioned above, this design is best suited for four rectangular solar cells connected in parallel, and therefore can be used as the layout for a four-cell solar module. Of course, it can also be extended to use rectangular solar cell modules of other specifications, provided that the current and voltage specifications allow.

[0044] The following is in conjunction with the appendix Figure 4The description describes a four-string rectangular solar cell arrangement structure formed by the arrangement of solar modules. It consists of two symmetrical sections, each with two strings of cells. The starting and ending points of these four strings are arranged on both sides, wrapping around each other from the inside out. The inner strings are arranged in a single-string, turning pattern. The middle part of the outer strings is also arranged in a single-string, turning pattern, plus two side columns, forming a "gate" shape that encloses the inner strings. Since the output voltage of each string must be consistent, the number of cells in each string is equal.

[0045] For the two battery strings in the upper half, y = w2 = w1 + 2, r2 = r1·(w1 - 2) / (w1 + 2) = r1·(y - 4) / y.

[0046] Then, based on r2 + r1 = x / 2, we can solve for r1 = x / 4·y / (y-2) and r2 = x / 4·(y-4) / (y-2).

[0047] Since r2 > 0, y > 4. Also, y must be even; otherwise, the endpoints of the upper and lower battery strings wouldn't converge. Therefore, y must be at least 6. This arrangement of components requires at least 6 columns, which perfectly satisfies the width of the current large-format design. After determining y, we can obtain x based on the total number of battery cells in the component = x·y, and then obtain r. Because r must be an integer, the number of rows x cannot be arbitrarily chosen.

[0048] Taking a mainstream component with a width of 6 columns as an example, according to the aforementioned derivation, y=6, r1=3 / 8·x, r2=x / 8.

[0049] To achieve a module with current and voltage specifications close to the original 60-cell full-panel design, 60 four-cell modules need to be strung together, totaling 4 strings and 240 cells. Therefore, x=40, r1=15, r2=5. Essentially, this means... Figure 4 Magnified 5 times vertically. The complete layout is as follows: Figure 5 .

[0050] To approximate the original 72-cell full-cell design, 72 four-cell batteries need to be strung together, resulting in 4 strung groups of 288 cells. Therefore, x=48, r1=18, r2=6. Essentially, this involves... Figure 4 It is magnified 6 times in the vertical direction.

[0051] Because both designs have 6 columns, their length and width are basically the same as similar components, ensuring maximum transportation and installation compatibility.

[0052] If we deviate from the conventional approach and design the component with 8 columns, then y=8, r1=x / 3, r2=x / 6.

[0053] To achieve a module with current and voltage specifications close to the original 60-cell full-size module, it is necessary to use 60 four-cell modules as a string, for a total of 4 strings, or 240 cells. Therefore, x=30, r1=10, r2=5, meaning the module has 30 rows and 8 columns, with the inner string having 10 rows and 6 columns, and the middle part of the outer string having 5 rows.

[0054] To approximate the original 72-cell full-size design, 72 four-cell batteries need to be strung together, resulting in 4 strungs and 288 cells. Therefore, x=36, r1=12, r2=6, meaning the component has 36 rows and 8 columns, with the inner string having 12 rows and 6 columns, and the middle part of the outer string having 6 rows.

[0055] These two designs are quite similar in length and width, resulting in a "short and stout" shape, especially the 60-piece set, which is very close to a square. More shape options allow for greater adaptability to various usage scenarios.

[0056] The following example illustrates the case where N=3 strings:

[0057] Let w1=4 again. Then, since the number of columns y= w3=8, r2= r1 / 3, r3= r1 / 6, we can solve for r1=2 / 3·x, r2=2 / 9·x, and r3=1 / 9·x.

[0058] Therefore, if we want to get close to the current and voltage specifications of the original 60-cell module, we would use 60 three-cell modules as a string, for a total of 3 strings of 180 cells. However, x = 180 / 8 is not divisible, so this design is not feasible.

[0059] To achieve a module with current and voltage specifications close to the original 72-cell full-panel design, using 72 three-cell modules per string, totaling 3 strings and 216 cells, with x=27, r1=18, r2=6, and r3=3, this design is feasible, equivalent to... Figure 6 Magnified vertically by 3 times.

Claims

1. Solar module arrangement method, the number of cell strings N≥4, when N is even, divide into two parts symmetrically, each part has N / 2 strings of cells, the starting point and the end point of the above strings are arranged in two sides, from inside to outside, the innermost string is a single string of turning arrangement; the middle part of all outer strings is also a single string of turning arrangement, plus two side columns to cover the inner strings, the number of cells in each string is equal; Let the width of string n be w n , and the height of string n be r n , then the width of the outer string (n+1) is w n+1 = w n + 2, and the height is r n+1 , by the number of tiles of two strings being equal, we get r n+1 ·w n+1 =r n · (w n - 2), that is r n+1 = r n ·(w n - 2) / (w n +2), because w n is even and at least 4, assuming the innermost string w1=4, we easily get w n = 2 · (n+1), and in turn we can get the recursive relationship: r2= r1 · 2 / 6 r3 = r1· 2·4 / (6·8) r4= r1· 2·4·6 / (6·8·10) …… r n = r1·2 / [n ·(n+1)] Assuming the component array has x rows and y columns, according to Σr = x / 2, the outermost string w n = y, the corresponding r value in various cases can be solved, and the specific arrangement is obtained; wherein: N: represents the number of cell strings; n: represents the serial number; w: string width, in terms of the number of cells; r: string height (not including the outermost two side columns), in terms of the number of cells; x: module length, in terms of the number of cells; y: module width, in terms of the number of cells; When N is odd, the upper half or the lower half of the arrangement of 2N strings can be taken.

2. The four-string rectangular cell arrangement structure formed by the solar module arrangement method according to claim 1, characterized in that: Divide into two parts symmetrically, each part has 2 strings of cells, the starting point and the end point of the four strings are arranged in two sides, from inside to outside, the inner string is a single string of turning arrangement; the middle part of the outer string is also a single string of turning arrangement, plus two side columns to cover the inner string, the number of cells in each string is equal; For the two cell strings in the upper half, y = w2 = w1+2, r2 = r1·(w1 -2) / (w1+2) = r1·(y-4) / y, Then according to r2 + r1 = x / 2, r1= x / 4·y / (y-2), r2 = x / 4·(y-4) / (y-2) can be solved, r2>0, so y>4, and y should be even, otherwise the end points of the cell strings in the upper and lower parts cannot return together, so y is at least 6, that is, the module arranged in this way has at least 6 columns, which can meet the width of the current large version; after y is determined, according to the total number of cells in the module x·y, x can be obtained, and then r can be obtained; because r must be an integer, the number of rows x cannot be arbitrarily taken.

Images