Arrangement structure of anti-shading short lead assembly

Abstract

The utility model relates to an arrangement structure of an anti-shading short lead assembly, which is characterized in that a plurality of battery pieces are welded in series to form a battery piece string, a plurality of rows of battery piece strings are connected in parallel through interconnection strips, the battery piece strings connected in parallel are welded on a bus bar to form a parallel battery piece group, and a plurality of parallel battery piece groups are connected in series to form the anti-shading short lead assembly. A positive junction box is arranged at the positive output end of the battery piece rectangular array, a negative junction box is arranged at the negative output end of the battery piece rectangular array, diodes in the positive junction box and the negative junction box are connected with battery piece sets at the two ends in parallel, an intermediate junction box is assembled on a middle battery piece, and diodes in the intermediate junction box are connected with a middle battery piece set in parallel. And the formed assembly is arranged in the frame body, so that a complete arrangement structure of the short lead assembly is formed. According to the utility model, the influence of shading can be reduced, more power is generated compared with a traditional assembly, and intervals among arrays are reduced, so that the installed capacity is improved under the same area, the area utilization rate is improved, and the maximum generating capacity is obtained.

Description

Technical Field

[0001] The utility model relates to a short lead wire component and a shade arrangement scheme that is universal for horizontal and vertical laying and resistant to shade. The new component can generate more electricity than traditional components under shade conditions, thereby enabling photovoltaic power stations of the same area to obtain maximum power generation. Background Art

[0002] With the popularization of distributed solar power stations and the implementation of noon valley electricity policies in many provinces across the country, third-party investors in distributed power stations are currently facing vicious competition. On the one hand, rooftop resources are gradually decreasing and becoming increasingly difficult to obtain, and on the other hand, the electricity price discounts offered by investors are getting lower and lower. In order for third-party investors to obtain positive returns, third-party investors must carefully cultivate the roof design. After installing the power station, not only the maximum annual power generation per square meter of roof can be obtained, but also the maximum annual power generation per kilowatt of installed capacity must be considered.

[0003] To obtain the maximum power generation on the same roof, it is not possible to simply cover the entire roof with components. Instead, multiple factors must be fully considered: component type efficiency, single-sided or double-sided, array orientation, array angle, array spacing, inverters and corresponding strings, etc. The maximum installed capacity of multiple components at the expense of the array angle cannot achieve the maximum power generation on the same roof. According to the experiment, a normal array (no shade between arrays) is designed under the condition of selecting the best solar power generation angle of the local fixed array, and then the gap between the two arrays is reduced so that the bottom row of components of the same array works in full or part of the shade in winter. In this way, several arrays can be arranged and the installed capacity can be effectively increased. At the same time, special anti-shading components are selected to minimize the impact of shading on component power generation, so that the maximum power generation can be obtained on one roof.

[0004] Most of the common photovoltaic modules available on the market currently use three-part junction boxes, and the junction boxes are installed in the middle of the module. Figure 1 When ordering PV modules with junction boxes in the middle of the module, it is necessary to distinguish between horizontal and vertical installation. The length requirements of the cables on the junction boxes are different for horizontal and vertical installation.

[0005] Under normal circumstances, vertically mounted modules are modules with long frames adjacent to each other in the east-west direction and can be connected in series when the lead length of the junction box is about 0.3m. Horizontally mounted modules are modules with short frames adjacent to each other in the east-west direction and can be connected in series. The lead length of the traditional module junction box needs to be 1.1m-1.4m depending on the length of the module. If traditional photovoltaic modules with long leads are used in vertical installation, cables will be wasted. If modules with short leads are used in horizontal installation, the leads are not long enough and additional connecting wires will be added.

[0006] In the case of vertical installation, once the lower part of the module is shaded, more than one cell, the general photovoltaic whole-cell module on the market will almost 100% stop generating electricity. If the lower part of the conventional half-cell module is shaded by more than one half-cell, the power generation capacity will be reduced by almost 50%. In the case of horizontal installation, if the conventional 60 whole-cell (or 72 whole-cell) or 120 half-cell (or 144 half-cell) modules are shaded by more than one cell, the power generation capacity will be reduced by about 1 / 3.

[0007] Given that the performance of common components on the market today is affected by at least 1 / 3, or even 1 / 2, of 100% power generation once more than one cell is shaded, it is not possible to meet the requirement of less impact on power generation under shaded arrangements. Therefore, it is necessary to develop new components that can resist shade. Utility Model Content

[0008] The purpose of the utility model is to overcome the above-mentioned shortcomings and provide an arrangement structure of a short-lead component that is resistant to shading and can generate more electricity than traditional components under shading conditions.

[0009] The purpose of the utility model is achieved in this way:

[0010] The invention discloses an arrangement structure of an anti-shading short-lead assembly. A plurality of battery cells are welded in series to form a battery cell string. Then, a plurality of rows of battery cell strings are connected in parallel by interconnecting strips. The parallel battery cell strings are welded on a bus bar to form a parallel battery cell group. Then, a plurality of parallel battery cell groups are connected in series to form a battery cell rectangular array. A positive junction box is installed at the positive output end of the battery cell rectangular array, and a negative junction box is installed at the negative output end. The diodes in the positive junction box and the negative junction box are connected in parallel with the battery cell groups at both ends. An intermediate junction box is installed at the middle battery cell assembly. The diodes in the intermediate junction box are connected in parallel with the middle battery cell group. The formed assembly is installed in a frame, thereby forming a complete arrangement structure of the short-lead assembly.

[0011] When connecting two adjacent modules, the lead of the negative output junction box of the previous photovoltaic module is connected to the lead of the positive output junction box of the next photovoltaic module. After multiple photovoltaic modules are connected in this way, a string is formed.

[0012] Leave a 1cm gap between the battery cell and the frame to prevent dust accumulation.

[0013] The beneficial effects of the utility model are:

[0014] The utility model arranges several cells into a rectangular array in a regular manner, connects the cells in a certain arrangement, uses a junction box and a diode in an intermediate body, and then connects each group of cells in parallel to form a new type of photovoltaic module. This can reduce the impact of shading, generate more electricity than traditional modules, and reduce the interval between arrays, thereby achieving an increase in installed capacity and area utilization under the same area, and obtaining the maximum power generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the interior of a traditional half-cell module.

[0016] Figure 2 It is a schematic diagram of the utility model.

[0017] Figure 3 This is a schematic diagram of the connection between two adjacent components when laid horizontally.

[0018] Figure 4 This is a schematic diagram of the connection between two adjacent components when laid vertically.

[0019] Figure 5 Schematic diagram of the component's anti-dust design.

[0020] Figure 6 Schematic diagram of the shading condition when the components are laid horizontally.

[0021] Figure 7 Schematic diagram of the shading situation when the components are laid vertically.

[0022] Figure 8 This is a schematic diagram of the components in a horizontal array.

[0023] Fig. 9 This is a schematic diagram of the components when they are arranged in a vertical array.

[0024] Fig.10 This is a schematic diagram of the normal layout of color steel tiles on the north slope.

[0025] Fig.11 This is a schematic diagram of the shade arrangement of the north slope of the colored steel tiles.

[0026] Among them: battery cell 1, interconnection bar 2, bus bar 3, positive junction box 4, intermediate junction box 5, negative junction box 6, frame 7. DETAILED DESCRIPTION

[0027] See also Figures 2 to 11 The utility model relates to an arrangement structure of an anti-shading short-lead component, in which a plurality of battery cells 1 (silicon photovoltaic cells) are welded in series to form a battery cell string, and then a plurality of rows of battery cell strings are connected in parallel by interconnection bars 2, and the parallel battery cell strings are welded on a bus bar 3 to form a parallel battery cell group, and then a plurality of parallel battery cell groups are connected in series to form a rectangular array of battery cells.

[0028] The positive output end of the rectangular array of battery cells is equipped with a positive junction box 4, and the negative output end is equipped with a negative junction box 6. The diodes in the positive junction box 4 and the negative junction box 6 are connected in parallel with the battery cell groups at both ends. The middle battery cell is assembled with an intermediate junction box 5. The diodes in the intermediate junction box 5 are connected in parallel with the middle battery cell group. The formed assembly is installed in a frame 7, thereby forming a complete arrangement structure of the short lead assembly. It is better to select the middle position of the parallel battery cells as the installation position of the junction box.

[0029] When connecting two adjacent modules, connect the lead of the negative output junction box of the previous PV module to the lead of the positive output junction box of the next PV module. Multiple PV modules are connected in this way to form a string. Figure 3 , Figure 4 It can be seen that when laying horizontally, the lead wire of the junction box can be 0.3m. When laying vertically, the size of one end of the junction box can be 0.75m. The 0.75m can be used for both horizontal and vertical laying, and is obviously shorter than the 1.1-1.4m required by conventional components.

[0030] A gap of about 1 cm can be left between the battery cell 1 and the frame 7. The white glass area of ​​about 1 cm is used to prevent dust accumulation, which can solve the problem of dirt accumulation between the frame and glass of conventional components affecting the power generation of the battery cell.

[0031] When the components are arranged on colored steel tiles, the component layout diagram and array string can be Figure 3 or Figure 4 As shown, the distance between two adjacent rows of photovoltaic modules is Figure 3 , Figure 4 Shown in series.

[0032] When the modules are arranged on the ground or on a concrete roof, the module strings are arranged in a horizontal array, such as Figure 8 As shown, each array is equipped with three modules horizontally, and the two rows of modules on each array are connected in series to form a string. The modules in the bottom row can form a straight string, or the modules at the bottom of two adjacent arrays can be connected in series to form a U string.

[0033] When a horizontal array is used, three horizontal blocks are not the only solution. For example, the top two blocks can also be laid horizontally using other components, and the bottom block can be an anti-shading component. Moreover, the top two horizontal components can also be changed to vertical components, as long as the bottom component is an anti-shading component.

[0034] When a vertical array is used, two modules are installed vertically in each array to form a U string.

[0035] Under normal circumstances, there should be enough space between arrays to prevent shading in winter. However, since distributed power stations are built on roofs, where every inch of land is valuable and the area is limited, how to install more and generate more power has always been a challenging research topic. In order to avoid shading, the traditional design generally leaves a space between two adjacent arrays according to the height difference between the front and rear arrays × (2-2.5) times. The new anti-shading component can greatly compress the array spacing, improve the effective utilization rate of the roof and the ground, and increase the solar energy installation and corresponding power generation under the same area.

[0036] The following is a calculation of the proportion of components that can be installed in the same area after using the utility model and the corresponding power generation change rate:

[0037] According to experiments and experimental data, after adopting the new anti-shading component, the array spacing calculation formula is:

[0038] D=Ki*L*Sinθ or D=Ki*ΔH.

[0039] Where: D: array spacing;

[0040] △H: inter-array transition difference;

[0041] Ki: array spacing coefficient;

[0042] L: array component width;

[0043] θ: angle between the array and the ground;

[0044] Color steel south slope: Ki = 1;

[0045] Color steel north slope: Ki = 1.5;

[0046] Color steel east and west slope: Ki = 1.2;

[0047] Ground or concrete roof: Ki = 1 ～ 1.5.

[0048] In this way, the utility model can install about 20% to 40% more capacity than the conventional design under the condition of the same roof area. The annual power generation of the unit kilowatt component caused by shading is only reduced by about 2% to 5% compared with the non-shading arrangement according to different regions and different roofs.

[0049] 1. When the best solar angle of the fixed array on the cement roof is about 22°, the installed capacity can be increased by approximately:

[0050] according to Figure 8 Array, assuming the selected component size is 2200*1090, the optimal array angle is 22 degrees, and the middle interval under normal conditions without shading is D=2.2*3*(1.09+0.015)*sin22 0 =2.7m.

[0051] The shade row method is 1.35 times, so the interval is D = 1.35*3*(1.09+0.015)*sin22 0 =1.68m.

[0052] Under the condition of 2.2 times without shading, the area utilization rate is:

[0053]

[0054] Under the condition of 1.35 times of shading, the area utilization rate is:

[0055]

[0056] Therefore, the proportion of solar energy installed capacity increased by the shading arrangement method is approximately:

[0057]

[0058] A rough estimate of the impact of shading arrangement on local cement roofs on power generation:

[0059] After the power station selected new components and 1.35 times the shade arrangement, daily observations showed that there was no shade in the 8 months from mid-to-late March, April, May, June, July, August, September, October, and early to mid-November when the height difference was 1.35 times as the spacing, and 100% power generation was possible.

[0060] The solar cells will start to be shaded in late November, and by the end of January or early February, up to half of the lower row of components will be shaded. Then the shading will be gradually reduced until all shading is removed in early March.

[0061] The 2200×1090 module used in the design is a five-row 210-cell parallel module. The array is arranged in three rows of horizontal modules with a spacing of 1.68m, which can cover up to 50% of the bottom module. Assuming that the horizontal shading method is used to cover up to 50% of the cells of the bottom module, then relative to the remaining 2.5 modules array, a spacing of +0.5 module width has been left, and in fact, the calculation formula for no shading continues to be satisfied. Therefore, assuming that the gap between two modules is 1.5cm, then D=2.2 * sin22 0 * 2.5 * 1.105=2.28m.

[0062] The shading design uses the reserved spacing: 1.68 plus the half width of the shaded module 1.09 / 2 + the gap 0.015, a total of 2.24m, as the actual spacing basically meets 2.28m. Therefore, it can be determined that when the 1.68m spacing is selected, when three rows of modules are arranged horizontally in winter, the lower module will be shaded by half at most.

[0063] According to the statistics of the APP of power stations that have generated electricity without shade, the eight months from mid-to-late March (April, May, June, July, August, September, October and early November) account for about 80% of the total power generation, and the remaining four months account for about 20% of the annual power generation. In the remaining four months, the shade changes from 0% to 50% (i.e. half shade), and then from 50% shade to no shade. That is to say, the actual average utilization rate of the lowest shade components in these four months is about 75%.

[0064] Due to the special design of the utility model, in the case of horizontal laying, the power generation after shading in front and behind is basically proportional to the area illuminated by light. Therefore, the actual power generation ratio of the bottom module in the shaded condition to the unshaded condition throughout the year is estimated as follows:

[0065]

[0066] Considering that the other two modules are not shaded, the power generation of the three modules can reach 2.95A, and the actual impact is only 1.7%. Therefore, the spacing of the new modules is 1.68m, and when the capacity is increased by 21.6%, the overall power generation is only affected by 1.7%.

[0067] 2. When the best solar angle of the fixed array on the north slope of the steel tile roof is about 22°, after adopting the utility model:

[0068] Color steel tile factory buildings are divided into north-south slopes and east-west slopes according to their orientation. The current conventional arrangement method is flat paving. However, after flat paving, the power generation of the south slope, east slope and west slope is acceptable, while the power generation of the north slope is much worse. If the angle method is adopted, the best angle is adopted and no shading is guaranteed, the roof utilization rate is extremely low. Therefore, the following is a calculation of how to arrange the utility model on the north slope of the color steel tile and how much power can be generated.

[0069] like Fig.10 , take the north slope angle as 5°, the component width as 1.09m, and the actual installation angle as 22° (relative to the north slope color steel house, the component angle is 27°).

[0070] Next, we calculate the spacing between components. First, we calculate the spacing when there is no 5° inclination:

[0071] D1=2.2*1.09*sin22 0 =0.898m.

[0072] Then calculate the compensation at a 5° tilt angle.

[0073] D2: 2.2*(0.898+1.09*cos27°)sin5 0 =0.36.

[0074] Actual unshaded interval = 0.898 + 0.36 = 1.26 m (1.26).

[0075] (This is actually equivalent to a non-shading coefficient of 3.08 when calculating array spacing).

[0076] In this way, the utilization rate of the north slope at a spacing of 1.267m is:

[0077] like Fig.11 If the shade row method is used, and only 0.6m is left between the two arrays, the utilization rate can be increased to:

[0078]

[0079] Therefore, the proportion of solar energy installed capacity that can be increased by using the shading arrangement method is approximately:

[0080]

[0081] Next, we estimate the impact on power generation. We first calculate the maximum shading ratio A of the components when there is a 0.6m gap between the two arrays:

[0082] 0.60+1.09*A*cos27°=3.08*1.09*(1-A)*sin22 0 .

[0083] A=29.5% was calculated.

[0084] like Fig.11 The local array begins to be shaded in mid-to-late November and reaches maximum shade in mid-to-late January, then gradually decreases until there is no shade at all in early March.

[0085] Therefore, the actual average component utilization rate is about 85% during the four shade months.

[0086] The power generation capacity is 80% in the 8 months without shading and 20% in the 4 months with shading.

[0087] Therefore, the actual component power generation utilization rate is: 80%+20%×85.0%=97.0%.

[0088] That is, after adopting the shade arrangement method on the north slope of the color steel tile, using the best angle increases the solar energy installed capacity by about 41.9% compared to the non-shade arrangement, and only affects the overall power generation by 3.0%.

[0089] If cement roof is made of Fig. 9 The vertical laying method, due to the segmented design of the components, if the front array shades the rear array and covers the bottom section, the bypass diode in the junction box of the bottom section will be turned on, and the overall power generation will be affected by only a few percent. Compared with the traditional whole-piece components that do not generate 100% of power and half-piece components that affect 50% of power generation, the utility model undoubtedly has better performance and less impact.

[0090] Regardless of whether the components are laid horizontally or vertically, they can effectively deal with left and right shading and top and bottom shading, and can continue to generate more electricity than traditional components and achieve better power generation effects under shading conditions.

[0091] like Figure 6 When the utility model is laid horizontally, the components are shaded by the front array, and the power generation is basically proportional to the illuminated area. The non-shaded area does not affect the power generation. When the array is shaded by high obstacles on the left and right, such as a high parapet, only a fraction of the components on one side will be affected when the sun rises in the morning and sets in the evening. (Specifically, it depends on how many battery cell groups are connected in series and the number of batteries corresponding to each battery cell group)

[0092] like Figure 7 When the utility model is laid vertically, the shading of the components caused by the front array only affects the lower section being shaded, affecting about a fraction of the total area. For example, the shading caused by the left and right obstacles to the array only affects the power generation of the shaded area. However, considering the wooden barrel effect, if the south slope array is laid vertically and the same array is continuously connected in series, the east-west shading caused by the parapet will produce a wooden barrel effect, and the current of the unshaded components will be limited. Therefore, unless the components with consistent shading on the east and west sides are connected in series separately, the actual laying mode and the way of connecting the shaded strings separately can obtain greater benefits.

[0093] In addition, considering that multiple battery cells are connected in parallel, the current will be too large. In actual production, the battery cells can be cut into smaller pieces. For example, 210*210 can be cut into 210*52.5 or 210*35 strips before production, which will achieve better results.

[0094] In addition, according to observations, when the module is installed at a certain angle, dust accumulates in the 1cm area next to the bottom frame. The distance between the battery cell and the frame of the traditional module is very short, generally only a few mm. Therefore, dust often accumulates on the bottom frame glass of the module and gradually affects part of the bottom row of battery cells. This affects the normal power generation of the entire module or even the entire string of modules. Because the frame is about 1.5mm thick, the design of leaving more than 1cm blank can ensure that at a lower angle, dust accumulates in the white glass area of ​​no more than 1cm, thereby ensuring that all battery cells are not affected by dust accumulation and ensuring the normal power generation of the module. The positive factor brought about by this is that the 1cm blank design can avoid 3% (or even 5%) of the power generation affected by dust accumulation. This fully solves the problem that after the module has been used for a long time, even if it is cleaned frequently, the dirt between the frame and the glass of the traditional module is not easy to clean, causing the module to generate 3% to 5% less power.

[0095] In summary, the utility model fixed array photovoltaic power station, when using the best angle in the lower reaches of the Yangtze River, adopts a new anti-shading component and a corresponding shading arrangement scheme, which can increase the installed capacity by more than 21.6%, and the power generation loss caused by shading does not exceed 1.7%. Even more bold designs can be adopted, such as Fig.11 Increasing the installed capacity by 41.9% only affects the total power generation by 3.0%, and the anti-dust design can increase the power generation by about a few percent. The actual installed capacity of the utility model can be increased by 20% to 40% compared with the conventional design, and the actual increased power generation per square meter of roof or floor area can reach more than 40%. When achieving the same power generation, the floor area (or roof) can be effectively reduced by 40%. Compared with flat tiling, although the installed capacity has increased significantly, the power generation of each kilowatt component in the flat tiling situation is only about 80% of the optimal angle (there are differences in different regions, this is the data from Jiangyin), and the flat tiling cannot use bifacial components to obtain 15%-20% back gain. At the same time, dust easily accumulates on the surface of the flat tiling components, which will affect the power generation by at least 5%. Therefore, at an installed area utilization rate of 68.8% and an installed area utilization rate of 69.4%, bifacial power generation components are used. Although the installed capacity is 22% less than that of the flat tiling with an area utilization rate of 90%, the actual power generation of the same area is still more than 20% more than that of the flat tiling with an area utilization rate of 90%.

Claims

1. An arrangement structure of an anti-shading short lead assembly, characterized in that: Several battery cells are welded in series to form a battery cell string, and then several rows of battery cell strings are connected in parallel with interconnecting strips. The parallel battery cell strings are welded on the bus bar to form a parallel battery cell group. Then several parallel battery cell groups are connected in series to form a battery cell rectangular array. The positive output end of the battery cell rectangular array is equipped with a positive junction box, and the negative output end is equipped with a negative junction box. The diodes in the positive junction box and the negative junction box are connected in parallel with the battery cell groups at both ends. The middle battery cell is assembled with an intermediate junction box, and the diodes in the intermediate junction box are connected in parallel with the middle battery cell group. The formed assembly is installed in a frame, thereby forming a complete short-lead assembly arrangement structure.

2. The arrangement structure of the anti-shading short lead assembly according to claim 1, characterized in that: When connecting two adjacent modules, the lead of the negative output junction box of the previous photovoltaic module is connected to the lead of the positive output junction box of the next photovoltaic module. After multiple photovoltaic modules are connected in this way, a string is formed.

3. The arrangement structure of the anti-shading short lead assembly according to claim 1, characterized in that: Leave a 1cm gap between the battery cell and the frame to prevent dust accumulation.

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