Distributed roof photovoltaic grid-connected power generation system

Abstract

The invention relates to the field of photovoltaic power generation equipment, in particular to a distributed roof photovoltaic grid-connected power generation system which comprises a plurality of battery pieces and a one-way conduction module, the battery pieces are distributed in the horizontal direction, and the battery pieces are connected in series to form a plurality of power generation sub strings; the number of the battery pieces of the power generation sub-strings close to the outer ring is smaller than the number of the battery pieces of the power generation sub-strings close to the inner ring. The one-way conduction modules are arranged at the head end and the tail end of the power generation sub string in parallel. According to the invention, the adverse effect of shadow shielding on the photovoltaic system is reduced, so that the photovoltaic generating capacity is ensured.

Description

Technical Field

[0001] The present application relates to the field of photovoltaic power generation equipment, and in particular to a distributed rooftop photovoltaic grid-connected power generation system. Background Art

[0002] A distributed rooftop photovoltaic system is a photovoltaic power generation system installed on the roof of a building. With the continuous improvement of environmental protection standards, its application scope is gradually expanding, so as to make full use of the solar energy on the roof, convert the solar energy into electricity and integrate it into the power generation grid, reducing the consumption of non-renewable resources.

[0003] In the existing related technology, refer to Figure 1 The photovoltaic system includes a plurality of power generation strings, which are connected in series, and each power generation string also includes a plurality of battery cells connected in series, so that a high voltage is formed by connecting a plurality of battery cells in series.

[0004] In order to alleviate the impact of the hot spot effect, a single or multiple power-generating electronic strings will be connected in parallel to a unidirectional conduction module D, which is in a cut-off state when any cell of the power-generating electronic string is not blocked, and in a conduction state when any cell of the power-generating electronic string is blocked, thereby stopping the power-generating electronic string in the blocked area to avoid overheating and damage due to the power generation current of other cells. For details, please refer to the invention patent with announcement number CN 115395878 A, entitled A Smart Anti-Hot Spot Photovoltaic Module.

[0005] With regard to the above-mentioned related technologies, the solar cells near the outside are easily blocked by the parapet and the shadows of other new and old buildings with higher elevations, so that the photovoltaic electronic string where the solar cells are located is short-circuited by the unidirectional conduction module D, thereby affecting the photovoltaic power generation efficiency.

[0006] For example, refer to Figure 1 Under the cover of the shadow area S, the three columns of the left-side electricity-generating strings are all blocked by the cells 1, and thus the four columns of the left-side electricity-generating strings stop generating electricity under the action of the two unidirectional conduction modules 2 on the left. Moreover, as time goes by, when the shadow area S gradually moves to the right, more electricity-generating strings will stop generating electricity, which will have a greater adverse impact on the photovoltaic power generation. Summary of the invention

[0007] In order to reduce the adverse effects of shadowing on the photovoltaic system and thus ensure photovoltaic power generation, the present application provides a distributed rooftop photovoltaic grid-connected power generation system.

[0008] The distributed rooftop photovoltaic grid-connected power generation system provided in this application adopts the following technical solution: A distributed rooftop photovoltaic grid-connected power generation system, comprising a battery cell and a unidirectional conduction module, wherein the battery cell is provided with a plurality of battery cells, the plurality of battery cells are distributed in a horizontal direction, the plurality of battery cells respectively form a plurality of power generation strings, or the plurality of battery cells are connected in series to form a plurality of power generation strings; The number of cells in the power-generating substrings close to the outer circle is less than the number of cells in the power-generating substrings close to the inner circle; The one-way conducting modules are arranged in parallel at the head and tail ends of the electron-generating string.

[0009] By adopting the above technical solution, the power generation sub-strings closer to the outer circle that are more easily blocked by shadows are provided with fewer solar cells, so that the number of power generation sub-strings in which all solar cells stop generating electricity due to individual solar cells being blocked by shadows is reduced, thereby reducing the adverse effects of shadow blocking on the photovoltaic system, thereby ensuring photovoltaic power generation.

[0010] Optionally, the number of battery cells in the power generating substring close to the outer circle is less than or equal to 10.

[0011] By adopting the above technical solution, it is beneficial to reduce the adverse effect of shadowing on the photovoltaic system while reducing the rated withstand voltage of the unidirectional conduction module, thereby ensuring the photovoltaic power generation.

[0012] Optionally, the number of battery cells in the power generating substring close to the inner circle is less than or equal to 20.

[0013] By adopting the above technical solution, it is beneficial to reduce the adverse effect of shadowing on the photovoltaic system while reducing the rated withstand voltage of the unidirectional conduction module, thereby ensuring the photovoltaic power generation.

[0014] Optionally, the number of cells in the power generation substring close to the shadow area is less than the number of cells in the power generation substring far from the shadow area.

[0015] By adopting the above technical solution, the one-way conduction modules are set up in a targeted manner for the power generation electronic strings close to the shadow area, and then the setting density of the one-way conduction modules is allocated according to the actual shadow shielding situation, thereby ensuring good photovoltaic power generation while ensuring the cost.

[0016] Optionally, the number of cells in the power-generating substring close to the corner of the shadow area is less than the number of cells in the power-generating substring far from the shadow area.

[0017] By adopting the above technical solution, the boundary of the shadow area is usually set obliquely with the arrangement direction of each battery cell, so that when the shadow area gradually moves over time, the battery cells located at the corners of the shadow area are usually shaded for a longer time, thereby making it easier for the power generation substring near the corners of the shadow area to stop generating electricity for a long time. By specifically reducing the number of battery cells in the power generation substring near the corners of the shadow area, the number of affected battery cells can be effectively reduced.

[0018] Optionally, the distributed rooftop photovoltaic grid-connected power generation system also includes a unidirectional input module and a unidirectional output module, the unidirectional input module is connected in series to the negative pole of the distributed rooftop photovoltaic grid-connected power generation system, and the unidirectional output module is connected in series to the positive pole of the distributed rooftop photovoltaic grid-connected power generation system.

[0019] The adoption of the above technical solution is helpful to reduce the overheating and damage caused by the external reverse current on each battery cell after all the battery cells are blocked by shadows and stop working.

[0020] Optionally, a plurality of the electronic strings are connected in series end to end.

[0021] The adoption of the above technical solution is conducive to ensuring the power generation voltage of the distributed rooftop photovoltaic grid-connected power generation system.

[0022] Optionally, the battery cell is a half-cell battery cell.

[0023] The adoption of the above technical solution is helpful to reduce the internal loss of the battery cell.

[0024] In summary, the present application includes at least one of the following beneficial technical effects: 1. The power generation sub-strings closer to the outer circle that are more easily blocked by shadows are provided with fewer cells, so that the number of power generation sub-strings where all cells stop generating electricity due to individual cells being blocked by shadows is reduced, thereby reducing the adverse effects of shadow blocking on the photovoltaic system, thereby ensuring the photovoltaic power generation; 2. There are more one-way conduction modules near the outer ring, which limits the lateral spacing between two adjacent battery cells, which is conducive to reducing the length of the wiring harness required to connect the one-way conduction modules; 3. Targetedly encrypt the one-way conduction modules for the photovoltaic strings close to the shadow area, and then allocate the setting density of the one-way conduction modules according to the actual shadow blocking situation, so as to ensure good photovoltaic power generation while ensuring the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an overall schematic diagram of the existing power generation system of this application.

[0026] Figure 2 It is an overall schematic diagram of the power generation system of Example 1 of the present application.

[0027] Figure 3 It is a schematic diagram of the marking distribution of the battery cell in Example 1 of the present application.

[0028] Figure 4 This is a schematic diagram of the marking distribution of the one-way conduction module in Example 1 of the present application.

[0029] Figure 5 It is a schematic diagram of the implementation of Example 1 of the present application when individual power generation sheets are shielded.

[0030] Figure 6 It is a schematic diagram of the implementation of Example 1 of the present application when it is obscured by shadow S1.

[0031] Figure 7 It is a schematic diagram of the implementation of Example 1 of the present application when it is obscured by a shadow S.

[0032] Figure 8 It is a schematic diagram of the implementation of Example 2 of the present application when it is blocked by the moving shadow S.

[0033] Explanation of the reference numerals: 1. Battery cell; 2. One-way conduction module; 3. One-way input module; 4. One-way output module. DETAILED DESCRIPTION

[0034] The following is combined with Figure 1-8 This application is described in further detail.

[0035] Embodiment 1: Embodiment 1 of the present application discloses a distributed rooftop photovoltaic grid-connected power generation system. Figure 1 The distributed rooftop photovoltaic grid-connected power generation system includes a battery cell 1, a unidirectional conduction module 2, a unidirectional input module 3 and a unidirectional output module 4.

[0036] Reference Figure 2 , the unidirectional input module 3 is located at the negative pole of the power generation system, and the unidirectional output module 4 is located at the positive pole of the power generation system. In Example 1 of the present application, the unidirectional output module 4 and the unidirectional input module 3 are both diodes, the positive pole of the unidirectional output module 4 is connected in series to the negative pole of the power generation system, and the negative pole of the unidirectional input module 3 is connected in series to the positive pole of the power generation system.

[0037] Reference Figure 2, there are several battery cells 1, and the types of several battery cells 1 are all half-cell batteries, and several battery cells 1 are distributed in a horizontal and vertical grid array along the horizontal direction. Several battery cells 1 form several power-generating sub-strings one by one, or several battery cells 1 are connected in series to form several power-generating sub-strings, and several power-generating sub-strings are arranged in series head to tail. The number of battery cells 1 of the power-generating sub-string close to the outer circle is less than the number of battery cells 1 of the power-generating sub-string close to the inner circle. In addition, the number of battery cells 1 of the power-generating sub-string close to the outer circle is 1-10 pieces, and the number of battery cells 1 of the power-generating sub-string close to the inner circle is 2-20 pieces, so as to reduce the adverse effects of shadow shielding on the photovoltaic system under the premise of reducing the rated withstand voltage value of the unidirectional conduction module 2, thereby ensuring the photovoltaic power generation. Specifically, in Example 1 of the present application, the number of battery cells 1 of the power-generating sub-string close to the outer circle is 1 piece, and the number of battery cells 1 of the power-generating sub-string close to the inner circle is 2 pieces.

[0038] In addition, in the present application, "the power generation substrings near the outer circle" refers to: for any two adjacent power generation substrings distributed along the radial direction, one of the power generation substrings is closer to the edge of the array of battery cells 1 than the other power generation substring. Similarly, "the power generation substrings near the inner circle" refers to: for any two adjacent power generation substrings distributed along the radial direction, one of the power generation substrings is closer to the center of the array of battery cells 1 than the other power generation substring. "Radial direction" refers to: the direction corresponding to the straight line passing through the geometric center of the array of battery cells 1 in the horizontal direction.

[0039] There are a plurality of unidirectional conducting modules 2, which are respectively arranged corresponding to each power generation substring, and the unidirectional conducting modules 2 are arranged in parallel at the head and tail ends of the power generation substring. The rated withstand voltage of the unidirectional conducting module 2 is greater than the voltage formed by the series connection of each battery cell of the power generation substring, and the unidirectional conducting module 2 is in a cut-off state when any battery cell 1 of the power generation substring is not blocked, and is in a conducting state when any battery cell 1 of the power generation substring is blocked, so that the corresponding parallel power generation substring stops generating electricity when it is turned on.

[0040] In the embodiment 1 of the present application, for the convenience of subsequent description, a plurality of battery cells 1 and a plurality of unidirectional conductive modules 2 are marked respectively. Figure 3 , the cell 1 located in the lower left corner is marked as P11, and the cell 1 located in the upper right corner is marked as P66; refer to Figure 4 , the one-way conducting module 2 located at the lower left corner is marked as D21, and the one-way conducting module 2 located at the upper right corner is marked as D117.

[0041] Reference Figure 5 , when individual cell 1, such as P12, is shaded: D12 is turned on, causing P12 to stop generating electricity, so compared to Figure 1The power generation system shown in the figure reduces 5 solar cells 1 that stop generating power due to shading. For another example, when P22 or P32 is shaded, D62 is turned on, causing P22 and P32 to stop generating power. Figure 1 The power generation system shown reduces the number of solar cells 1 that stop generating electricity due to shading by four, thereby reducing the adverse effects of shadow shading on the photovoltaic system and ensuring the photovoltaic power generation.

[0042] Reference Figure 6 , when multiple cells 1 are shaded at the same time, for example, when the power generation system is shaded by shadow S1: When the power generation system is shaded by shadow S1: P11, P21 and P31 are shaded by shadow S1, at this time D21, D31 and D51 are turned on, and P11, P21 and P31 stop generating electricity, so compared with Figure 1 The power generation system shown reduces 15 solar cells 1 that stop generating electricity due to shading; For example, refer to Figure 7 , when the power generation system is under the shade of shadow S: P11, P21, P31, P12, P22, P32, P13, P23, P14, P15 and P16 are shaded by shadow S, at this time D21, D31, D51, D12, D62, D13, D44, D15, D16 and D27 are turned on, P11, P21, P31, P12, P22, P32, P13, P23, P14, P24, P15 and P16 stop generating electricity, so compared with Figure 1 The power generation system shown reduces 6 solar cells 1 that stop generating electricity due to shading, thereby reducing the adverse effects of shadow shading on the photovoltaic system and ensuring photovoltaic power generation.

[0043] The implementation principle of a distributed rooftop photovoltaic grid-connected power generation system in Example 1 of the present application is as follows: the power generation sub-strings closer to the outer circle that are more easily blocked by shadows are provided with fewer battery cells 1, so that the number of power generation sub-strings where all battery cells 1 stop generating electricity due to individual battery cells 1 being blocked by shadows is smaller, thereby reducing the adverse effects of shadow blocking on the photovoltaic system and ensuring the photovoltaic power generation.

[0044] Embodiment 2: Embodiment 2 of the present application discloses a distributed rooftop photovoltaic grid-connected power generation system, which is mainly different from Embodiment 1 in that the configuration of the power generation string and the configuration of the unidirectional conduction module 2 are different.

[0045] Reference Figure 7, the lower left of the power generation system is the shadow area, that is, the maximum area range that is more susceptible to the shadow shielding for a long time during the operation of the power generation system, and in Example 2 of the present application, the boundary of the shadow area is consistent with the shadow S. In addition, the number of battery cells 1 of at least one power generation sub-string located on the left side, that is, close to the shadow area, is reduced compared to the number of battery cells 1 of at least one power generation sub-string located on the right side, that is, far away from the shadow area. And for the power generation sub-strings all located on the left side, the number of battery cells 1 of the power generation sub-string close to the lower left side, that is, close to the corner of the shadow area, is further reduced compared to the number of battery cells 1 of the power generation sub-string close to the upper right side, that is, far away from the corner of the shadow area, so as to reduce the number of unidirectional conduction modules 2 arranged in parallel with both ends of the power generation sub-string, thereby reducing the adverse effects of shadow shielding under the premise of controlling the cost of the power generation system.

[0046] Continue to refer to Figure 8 , under the cover of shadow S, a total of 11 cells 1 stop generating electricity, so compared with Figure 1 The power generation system shown in the figure reduces 7 solar cells 1 that stop generating electricity due to shading. When the shadow S moves to the lower left over time and changes to the shadow S', a total of 4 solar cells 1 stop generating electricity, so compared with Figure 1 The power generation system shown in FIG. 1 reduces 14 cells 1 that stop generating electricity due to shading. When the shadow S' moves further to the lower left over time and changes to the shadow S", a total of 1 cell 1 stops generating electricity, so compared to Figure 1 The power generation system shown reduces five solar cells 1 that stop generating electricity due to shading, thereby reducing the adverse effects of shadow shading on the photovoltaic system and ensuring photovoltaic power generation.

[0047] The implementation principle of a distributed rooftop photovoltaic grid-connected power generation system in Example 2 of the present application is as follows: for the boundaries of the shadow area which are usually set at an angle to the arrangement direction of each battery cell 1, the number of battery cells 1 of the power generation string close to the corners of the shadow area is targetedly reduced, and the number of battery cells 1 of the power generation string away from the corners of the shadow area is increased, so that when the battery cells 1 gradually move in the shadow area over time, the number of affected battery cells 1 is reduced while ensuring the cost.

[0048] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A distributed rooftop photovoltaic grid-connected power generation system, characterized by: A battery cell (1) and a unidirectional conduction module (2), wherein the battery cell (1) is provided with a plurality of battery cells (1), the plurality of battery cells (1) are distributed in a horizontal direction, the plurality of battery cells (1) respectively form a plurality of electron-emitting strings, or the plurality of battery cells (1) are connected in series to form a plurality of electron-emitting strings; The number of battery cells (1) of the power-generating sub-string close to the outer circle is less than the number of battery cells (1) of the power-generating sub-string close to the inner circle; The one-way conducting module (2) is arranged in parallel at the head and tail ends of the electron-generating string.

2. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1, characterized in that: The number of battery cells (1) of the power generating string close to the outer circle is less than or equal to 10.

3. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1 or 2, characterized in that: The number of battery cells (1) of the power generating electronic string close to the inner circle is less than or equal to 20.

4. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1, characterized in that: The number of battery cells (1) of the power-generating substring close to the shadow area is less than the number of battery cells (1) of the power-generating substring far from the shadow area.

5. A distributed rooftop photovoltaic grid-connected power generation system according to claim 4, characterized in that: The number of battery cells (1) of the power-generating substring close to the corner of the shadow area is less than the number of battery cells (1) of the power-generating substring far from the shadow area.

6. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1, characterized in that: It also includes a unidirectional input module (3) and a unidirectional output module (4), wherein the unidirectional input module (3) is connected in series to the negative pole of the distributed rooftop photovoltaic grid-connected power generation system, and the unidirectional output module (4) is connected in series to the positive pole of the distributed rooftop photovoltaic grid-connected power generation system.

7. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1, characterized in that: A plurality of said electronic strings are arranged in series end to end.

8. A distributed rooftop photovoltaic grid-connected power generation system according to claim 1, characterized in that: The type of the battery cell (1) is a half-cell battery cell.

Images