A battery string and photovoltaic assembly

Abstract

This utility model discloses a battery string assembly and a photovoltaic module. The battery string assembly may include: a first battery column, a second battery column, a first intermediate busbar, a second intermediate busbar, and two edge busbars; both the first and second battery columns contain 2N+1 battery cells; in the first battery column, the first polarity grid line of the Nth battery cell and the first polarity grid line of the N+1th battery cell are connected to the first intermediate busbar; in the second battery column, the second polarity grid line of the N+1th battery cell and the second polarity grid line of the N+2th battery cell are connected, with the first and second polarity grid lines having opposite polarities; the second intermediate busbar is located in the extension direction of the first busbar and is connected to the second polarity grid line of the N+1th battery cell in the second battery column; the first and second battery columns are connected in series via the two edge busbars. This structure can balance the reverse voltage of the bypass diode connected to the battery string assembly and the series loss of the battery string.

Description

Technical Field

[0001] This utility model relates to a battery string and a photovoltaic module. Background Technology

[0002] For photovoltaic (PV) modules with a busbar, bypass diode, and current leads in the middle region, an equal number of cells are typically needed on both sides of the busbar in the middle region to ensure current balance. This requires an even number of cells along the length of the PV module to maintain this balance. However, research has found that string loss is related to the size of the cells; smaller cells result in lower string loss. To accommodate the entire PV module, the number of cells must increase. To ensure the busbar is located in the middle region, the number of cells along the length of the PV module must be an even multiple. This increase in the number of cells necessitates a higher reverse voltage limit for the bypass diode, leading to increased costs. For some bypass diodes, the reverse voltage limit may correspond to an odd number of cells (e.g., 2N+1, where N is a positive integer). In such cases, the existing even-number cell structure of PV modules cannot adequately balance the reverse voltage of the bypass diode and the string loss. Utility Model Content

[0003] In view of this, the present invention provides a battery string assembly and a photovoltaic module. The battery string assembly includes two battery strings, each containing an odd number of cells, which can better balance the reverse voltage of the bypass diode connected to the battery string assembly and the string loss of the battery string. Furthermore, the second intermediate bus of the battery string assembly is located in the extension direction of the first intermediate bus, so that the second intermediate bus and the first intermediate bus are aligned, which can avoid the introduction of flying wires and ensure the appearance consistency of the battery string assembly and the photovoltaic module containing the battery string assembly.

[0004] Specifically, this utility model provides the following technical solution:

[0005] In a first aspect, the present invention provides a battery string assembly, comprising: a first battery column, a second battery column, a first intermediate busbar, a second intermediate busbar, and two edge busbars;

[0006] Both the first battery column and the second battery column contain 2N+1 battery cells arranged along a first direction, where N is a positive integer;

[0007] In the first battery array, the first polarity grid line of the Nth battery cell and the first polarity grid line of the N+1th battery cell are connected by a first conductor extending along the first direction, the first battery cell to the Nth battery cell are connected in series, and the N+1th battery cell to the 2N+1th battery cell are connected in series.

[0008] In the second battery array, the second polarity grid line of the (N+1)th battery cell and the second polarity grid line of the (N+2)th battery cell are connected by a second conductor extending along the first direction. The first battery cell to the (N+1)th battery cell are connected in series, and the (N+2)th battery cell to the (2N+1)th battery cell are connected in series. The polarities of the first polarity grid line and the second polarity grid line are opposite.

[0009] The first intermediate busbar extends along a second direction perpendicular to the first direction and is connected to the first conductor; the second intermediate busbar extends along the second direction and is located in the extension direction of the first intermediate busbar and is connected to the second conductor.

[0010] The first cell of the first battery column and the first cell of the second battery column are connected in series via an edge busbar;

[0011] The 2N+1th cell of the first battery column and the 2N+1th cell of the second battery column are connected in series via another edge busbar.

[0012] Secondly, this utility model provides a photovoltaic module, including: one or more battery string groups provided in the first aspect embodiment.

[0013] The first aspect of the above-mentioned utility model has the following advantages or beneficial effects:

[0014] The first and second battery columns in the battery string assembly provided in this embodiment of the invention both contain an odd number of battery cells. The first polarity grid lines of the Nth and N+1th battery cells in the first battery column are connected to a first intermediate busbar via a first wire. Similarly, the second polarity grid lines of the N+1th and N+2th battery cells in the second battery column are connected to a second intermediate busbar via a second wire. This allows the second intermediate busbar to be located in the extension direction of the first intermediate busbar, enabling the parallel bypass diodes in the battery string assembly to connect to an odd number of battery cells, thus better balancing the reverse voltage of the bypass diodes and the series loss of the battery string. Furthermore, the second intermediate busbar of the battery string assembly is located in the extension direction of the first intermediate busbar, aligning the second and first intermediate busbars. This avoids introducing flying wires and ensures the appearance consistency of the battery string assembly and the photovoltaic module containing it.

[0015] Furthermore, a battery string group is formed by an odd number of battery cells forming a first battery column and an odd number of battery cells forming a second battery column. With the help of an edge busbar, the first to Nth battery cells of the first battery column are connected in series with the first to N+1th battery cells of the second battery column to form a first battery string. The N+1th to 2N+1th battery cells of the first battery column are connected in series with the N+2th to 2N+1th battery cells of the second battery column to form a second battery string. That is, the first battery string and the second battery string group still consist of 2N+1 battery cells connected in series. Compared with the existing battery string with 2N battery cells connected in series, by adding one battery cell in each battery string, the size of the battery cells is reduced, which can effectively reduce the string loss. Compared with the battery string with 2N+2 battery cells connected in series, the breakdown problem of the bypass diode can be avoided, and the efficiency of the battery string group can be increased. Attached Figure Description

[0016] Figure 1 This is a structural diagram showing the relative relationship between the battery string and the intermediate busbar, provided by existing technology.

[0017] Figure 2 This is a schematic diagram of the first structure of the battery string assembly according to an embodiment of the present utility model;

[0018] Figure 3 This is a schematic diagram of a second structure of a battery string according to an embodiment of the present utility model;

[0019] Figure 4 This is a schematic diagram of a third structure of a battery string according to an embodiment of the present utility model;

[0020] Figure 5 This is a schematic diagram of the relative relationship of battery strings in the first structure of a photovoltaic module according to an embodiment of the present utility model;

[0021] Figure 6 This is a schematic diagram of the relative relationship of battery strings in the second structure of a photovoltaic module according to an embodiment of the present invention;

[0022] Figure 7A According to the embodiments of this utility model, the corresponding Figure 2 A cross-sectional schematic diagram of the battery string assembly with the F1-F1 cut line;

[0023] Figure 7B According to the embodiments of this utility model, the corresponding Figure 3 A cross-sectional schematic diagram of the battery string assembly with the F2-F2 cut line;

[0024] Figure 8 According to the embodiments of this utility model, the corresponding Figure 5 A schematic diagram of a cross-section of a photovoltaic module with AA-cut lines;

[0025] Figure 9 According to the embodiments of this utility model, the corresponding Figure 5 A schematic diagram of a cross-section of a photovoltaic module with BB cut lines;

[0026] Figure 10 According to the embodiments of this utility model, the corresponding Figure 5 A cross-sectional schematic diagram of a photovoltaic module with a CC-cut line;

[0027] Figure 11 According to the embodiments of this utility model, the corresponding Figure 5 A schematic diagram of a cross-section of a photovoltaic module with DD cut lines;

[0028] Figure 12 According to the embodiments of this utility model, the corresponding Figure 5 A schematic diagram of a photovoltaic module with EE cut lines.

[0029] The attached figures are labeled as follows:

[0030] 10-Battery string group; 11-First battery column; 12-Second battery column; 13-First intermediate busbar; 14-Second intermediate busbar; 15-Edge busbar; 16-Insulating pad; 20-Bypass diode; 30-First polarity solder strip; 40-Second polarity solder strip; 50-Cover plate; 60-Encapsulating film; 70-Backplate; 100-Intermediate busbar; 200-Battery string with N series-connected cells; 300-Series busbar. Detailed Implementation

[0031] In existing technologies, photovoltaic modules with a busbar in the middle region typically consist of strings of cells with the same number of cells arranged on both sides of the middle busbar, such as... Figure 1 An exemplary structural relationship is given between a cell string 200 with N cells and an intermediate busbar 100 in a conventional photovoltaic module. Figure 1As shown, battery strings 200 with N series-connected battery cells are arranged on both sides of the intermediate busbar 100, where N is a positive integer. The battery strings 200 with N series-connected battery cells arranged on both sides of the intermediate busbar 100 are connected in parallel through the intermediate busbar 100. The battery strings 200 with N series-connected battery cells located above the intermediate busbar 100 in the first column and the battery strings 200 with N series-connected battery cells located above the intermediate busbar 100 in the second column are connected in series via a series busbar 300 to form a battery string with 2N series-connected battery cells. Similarly, the battery strings 200 with N series-connected battery cells located below the intermediate busbar 100 in the first column and the battery strings 200 with N series-connected battery cells located below the intermediate busbar 100 in the second column are connected in series via a series busbar 300 to form a battery string with 2N series-connected battery cells. The two battery strings with 2N series-connected battery cells are connected in parallel via the intermediate busbar 100 and a diode is connected in parallel at the same time. The diode controls the battery string formed by the 2N series-connected battery cells. In existing photovoltaic modules, the same number of solar cells are distributed on both sides of the central busbar 100. That is, the column containing the central busbar 100 has 2N solar cells (i.e., an even number of solar cells) along the length of the photovoltaic module. The value of N is generally determined by the reverse breakdown voltage of the bypass diode connected to the battery string and the series loss of the battery string.

[0032] Regarding the relationship between solar cells and solar strings, the open-circuit voltage of a solar cell is independent of its size, while the current in a solar cell decreases as its size decreases. Therefore, the smaller the cell size, the smaller the current, and the smaller the energy loss (i.e., string loss) of the solar string formed by connecting cells in series. To arrange the entire photovoltaic module, reducing the cell size allows for a corresponding increase in the number of cells.

[0033] Regarding the reverse breakdown voltage of bypass diodes connected in parallel with battery strings, under normal operating conditions of photovoltaic modules, the bypass diodes will withstand a reverse bias voltage (the magnitude of which is related to the number of cells in the battery string connected in parallel with the bypass diode). At this time, the leakage current through the bypass diode is very small, and the bypass diode is reverse disconnected. When one cell in the battery string connected in parallel with the bypass diode is shaded, it can no longer receive sunlight and stops generating photocurrent. The shaded battery string becomes a high-impedance load and withstands the reverse voltage generated by other normal battery strings. The bypass diode conducts in the forward direction. The more cells in the battery string, the greater the reverse voltage that the bypass diode withstands. When the reverse voltage exceeds the rated value that the bypass diode can withstand, the bypass diode will break down. Furthermore, since the reverse bias leakage current of the bypass diode increases with the temperature of the bypass diode, when the bypass diode is reverse biased at a high temperature, a large leakage current will flow through the bypass diode, causing the bypass diode temperature to increase significantly. When the heat generated by the bypass diode exceeds the maximum heat dissipation capacity of the junction box where the bypass diode is located, the temperature and leakage current of the bypass diode will continue to rise, eventually leading to the breakdown of the bypass diode, causing a short circuit in the battery string and loss of power generation of the module. We call this phenomenon the bypass diode thermal runaway (thermal escape / thermal breakdown) effect. Furthermore, the increased leakage current through shaded solar cells (leakage current refers to the unutilized current in a photovoltaic module, specifically manifested as current escaping through abnormal paths or flowing in the reverse direction under non-ideal operating conditions such as shaded or defective cells. This current does not participate in power generation but instead causes energy loss and localized heating within the photovoltaic module) leads to an increase in the transient current across the bypass diode during forward conduction. This causes the bypass diode to heat up, reducing its reverse breakdown voltage and increasing the risk of reverse breakdown. Therefore, it can be seen that the more solar cells a battery string connected in parallel with the bypass diode contains, the greater the voltage and transient current across the bypass diode during forward conduction, significantly increasing the risk of reverse breakdown.

[0034] As shown above, for photovoltaic modules of the same size, the number of cells is related to the cell size, the reverse breakdown voltage of the bypass diode, and the series loss. Smaller cell sizes result in a larger number of cells, leading to more cells per string in the photovoltaic module (i.e., a larger N). While this reduces string loss, a larger number of cells in a string requires a higher reverse breakdown voltage from the parallel-connected bypass diode, increasing its cost. Conversely, larger cell sizes result in a smaller number of cells per string in the photovoltaic module. While this reduces the reverse breakdown voltage and cost of the bypass diode, it leads to higher string loss. Therefore, to minimize string loss while meeting the bypass diode's reverse voltage requirements (controlling its cost), the cell size should be reduced as much as possible to balance the reverse breakdown voltage of the bypass diode with the string loss.

[0035] For current photovoltaic (PV) module designs (where the same number of cells are arranged on both sides of the central busbar, i.e., each column contains an even number of cells), research has found that when the number of cells on both sides of the central busbar is N, the total number of cells along the length of the PV module is 2N, and there is still some room for adjustment in the reverse voltage of the bypass diode. However, when the number of cells on both sides of the central busbar is N+1, the total number of cells along the length of the PV module is 2N+2, and the reverse voltage of the bypass diode will break down. Therefore, to further balance the reverse breakdown voltage of the bypass diode and the series loss of the cell string, maximize the application of the bypass diode, and minimize the series loss of the cell string to improve the efficiency of the PV module, it is necessary to design a PV module in which the number of cells along the length of the PV module is an odd number.

[0036] To address the aforementioned problems, this utility model provides a novel structure of battery string arrays for use in photovoltaic modules, a novel structure of photovoltaic modules, and a method for their fabrication.

[0037] The photovoltaic modules involved in this embodiment can be any type of photovoltaic module, such as double-glass modules, single-glass modules, etc. The solar cells used in the photovoltaic modules can be any type of solar cell with main grid lines or gridless solar cells (such as silicon-based solar cells, perovskite solar cells, etc., where silicon-based solar cells can be of the cross-type, back-contact type, or type with electrodes on both sides, etc.) cut from.

[0038] The terms "first," "second," etc., used in this embodiment of the utility model are used to distinguish components located in different positions or with different structures, and are not limitations on the number or order of the components. For example, the first battery column 11 refers to a column containing the first to the (2N+1)th battery cells along a certain direction (e.g., Figures 2 to 6 A battery column (arranged in the vertical direction as shown) is a column of batteries. The second battery column 12 refers to the column containing the first to the (2N+1)th battery cells arranged along the vertical direction. Figures 2 to 6 The image shows a row of batteries arranged vertically. For example, the first intermediate busbar 13 refers to the busbar connected to the first battery row 11, and the second intermediate busbar 14 refers to the busbar connected to the second battery row 12, etc.

[0039] The series connection of multiple battery cells in this embodiment generally refers to a series structure where the multiple battery cells are connected in series. In each pair of adjacent battery cells, the positive grid line of one battery cell is electrically connected to the negative grid line of the other battery cell. For example, the series connection of the first to Nth battery cells can be such that the positive grid line of the first battery cell is electrically connected to the negative grid line of the second battery cell, the positive grid line of the second battery cell is electrically connected to the negative grid line of the third battery cell, and so on, with the positive grid line of the (N-2)th battery cell connected to the (N-1)th battery cell. The negative grid lines of the first cell are electrically connected, and the positive grid lines of the (N-1)th cell are electrically connected to the negative grid lines of the Nth cell. Alternatively, the first to Nth cells can be connected in series such that the negative grid lines of the first cell are electrically connected to the positive grid lines of the second cell, the negative grid lines of the second cell are electrically connected to the positive grid lines of the third cell, and so on, with the negative grid lines of the (N-2)th cell being electrically connected to the positive grid lines of the (N-1)th cell, and the negative grid lines of the (N-1)th cell being electrically connected to the positive grid lines of the Nth cell.

[0040] The battery array involved in this embodiment of the utility model generally refers to a structure formed by connecting multiple battery cells in the same row, such as... Figures 2 to 6 As shown, multiple solar cells in the same column are connected from bottom to top or from top to bottom to form a solar cell column, and the solar cells in a solar cell column can be connected in series or in parallel.

[0041] The connection between adjacent solar cells involved in this embodiment of the invention (which can be a series connection or a parallel connection between adjacent solar cells) can be achieved through solder ribbons or conductive adhesive, etc., and the specific connection method is not limited in this embodiment of the invention. In addition, the connection between adjacent solar cells can be a solder ribbon connection to the main grid of the solar cell electrode, or for solar cells without main grids, a solder ribbon connection to the fine grid of the solar cell electrode.

[0042] The "nth" battery cell in this embodiment of the utility model generally refers to, for a battery array, in the direction of the battery array's extension (e.g., ...). Figures 2 to 6 As shown (from bottom to top), the cell number indicates the cell's position in the sequence. For example, as shown... Figures 2 to 6As shown, from bottom to top, the first battery cell is the 1st battery cell, the second battery cell is the 2nd battery cell, the Nth battery cell is the Nth battery cell, and so on.

[0043] In the accompanying drawings provided in this utility model embodiment, to clearly distinguish the positive grid lines of the battery cell, the negative grid lines of the battery cell, the solder strips or wires connected to the positive grid lines of the battery cell, and the solder strips or wires connected to the negative grid lines of the battery cell, red lines represent the negative grid lines of the battery cell or the solder strips or wires connected to the negative grid lines of the battery cell, and black lines represent the positive grid lines of the battery cell or the solder strips or wires connected to the positive grid lines of the battery cell. Furthermore, to clearly illustrate the electrical connection relationships provided in this utility model embodiment, Figures 1 to 6 The following explanation uses a back-contact solar cell as an example.

[0044] in, Figures 2 to 4 The following are partial structural schematic diagrams of battery string groups with different structures provided in the embodiments of this utility model; Figure 5 and Figure 6 This diagram illustrates the relative relationships between the various cell strings in a photovoltaic module. Figure 7A and Figure 7B A cross-sectional schematic diagram of the battery string assembly is shown; Figures 8 to 12 The diagram shows cross-sectional structures at different locations of a photovoltaic module.

[0045] This utility model embodiment provides a battery string group 10. For example... Figures 2 to 4 As shown, the battery string group 10 may include: a first battery column 11, a second battery column 12, a first intermediate busbar 13, a second intermediate busbar 14, and two edge busbars 15.

[0046] Specifically, such as Figures 2 to 4 As shown, both the first battery column 11 and the second battery column 12 contain 2N+1 solar cells, where N is a positive integer. That is, both the first battery column 11 and the second battery column 12 contain an odd number of solar cells. The value of N can be determined based on the threshold of the reverse voltage of the bypass diode 20 and the size of the solar cells cut into solar cells. It is worth noting that in... Figures 2 to 4 In this example, the number of battery cells in a battery column is counted from bottom to top.

[0047] Furthermore, in the first battery array 11, the first polarity grid line of the Nth battery cell and the first polarity grid line of the (N+1)th battery cell are connected by a first conductor (e.g., solder ribbon), the first conductor is connected to the first intermediate busbar 13, and the first to Nth battery cells are connected in series, and the (N+1)th to 2N+1th battery cells are connected in series; specifically, the second polarity grid line of the Nth battery cell and the first polarity grid line of the (N-1)th battery cell are connected by solder ribbon, and the second polarity grid line of the (N-2)th battery cell and the first polarity grid line of the (N-3)th battery cell are connected by solder ribbon. The first polarity grid lines of the first cell are connected by solder ribbons. Similarly, the second polarity grid lines of the second cell are connected to the first polarity grid lines of the first cell by solder ribbons; correspondingly, the second polarity grid lines of the (N+1)th cell are connected to the first polarity grid lines of the (N+2)th cell by solder ribbons, the second polarity grid lines of the (N+2)th cell are connected to the first polarity grid lines of the (N+3)th cell by solder ribbons, and so on, until the second polarity grid lines of the 2Nth cell are connected to the first polarity grid lines of the 2N+1th cell by solder ribbons. The first polarity grid line can be a positive grid line (such as a fine positive grid line or a main positive grid line) or a negative grid line (such as a fine negative grid line or a main negative grid line). For example,... Figures 2 to 4 As shown, the first polarity grid line is a negative grid line. Specifically, the first conductor is a first polarity solder strip 30, which connects the negative grid line of the Nth cell and the negative grid line of the (N+1)th cell. That is, in the first cell array 11, the Nth cell and the (N+1)th cell are connected in parallel. The connection between the first intermediate busbar 13 and the first polarity solder strip 30 is essentially the connection between the first intermediate busbar 13 and the negative grid line of the Nth cell and the (N+1)th cell, thus realizing the parallel connection of the Nth cell and the (N+1)th cell in the first cell array 11. The solder strip can extend along the length direction of the cell string arrangement, and the busbar can extend along a second direction perpendicular to the grid line and the solder strip.

[0048] In the second battery array 12, the second polarity grid line of the N+1th battery cell and the second polarity grid line of the N+2th battery cell are connected by a second conductor, which is connected to the second intermediate busbar 14. The first to N+1 solar cells are connected in series, and the N+2 to 2N+1 solar cells are connected in series. Specifically, the first polarity grid line of the N+1 solar cell is connected to the second polarity grid line of the Nth solar cell via solder ribbon, the first polarity grid line of the Nth solar cell is connected to the second polarity grid line of the N-1th solar cell via solder ribbon, and so on. The first polarity grid line of the second solar cell is connected to the second polarity grid line of the first solar cell via solder ribbon; correspondingly, the first polarity grid line of the N+2 solar cell is connected to the second polarity grid line of the N+3 solar cell via solder ribbon, the first polarity grid line of the N+3 solar cell is connected to the second polarity grid line of the N+4 solar cell via solder ribbon, and so on. The first polarity grid line of the 2Nth solar cell is connected to the second polarity grid line of the 2N+1 solar cell via solder ribbon. The polarities of the first and second polarity grid lines are opposite. When the first polarity gate line is a negative gate line, the second polarity gate line is a positive gate line; when the first polarity gate line is a positive gate line, the second polarity gate line is a negative gate line. For example, as... Figures 2 to 4 As shown, the second polarity grid line is the positive grid line. Specifically, the second conductor is the second polarity solder strip 40, which connects the positive grid line of the N+1th cell and the positive grid line of the N+2th cell. That is, in the second cell array 12, the N+1th cell and the N+2th cell are connected in parallel.

[0049] The second intermediate busbar 14 extends along the second direction and is located in the extension direction of the first intermediate busbar 13; for example, for such Figures 2 to 4 As shown, the first intermediate busbar 13 is connected to the first polarity solder strip 30, so that the first intermediate busbar 13 can be set at any position in the length direction of the first polarity solder strip 30, as long as it is connected to the first intermediate busbar 13. The second intermediate busbar 14 is connected to the second polarity solder strip 40, so that the second intermediate busbar 14 can be set at any position in the length direction of the second polarity solder strip 40, as long as it is connected to the second intermediate busbar 14. The flexible positions of the first intermediate busbar 13 and the second intermediate busbar 14 can be achieved so that the second intermediate busbar 14 is located in the extension direction of the first intermediate busbar 13. This avoids the need for flying wire connection when the battery column has an odd number of battery cells, where the first intermediate busbar 13 and the second busbar 14 are staggered.

[0050] Understandably, while the second intermediate busbar 14 is connected to the second polarity grid line of the N+1th cell of the second battery column 12 via the second polarity solder strip 40, since the second polarity solder strip 40 simultaneously connects the second polarity grid line of the N+1th cell and the second polarity grid line of the N+2th cell of the second battery column 12, the second intermediate busbar 14 can also be connected to the second polarity grid line of the N+2th cell of the second battery column 12 via the second polarity solder strip 40.

[0051] Furthermore, such as Figures 2 to 4 as well as Figure 7A and Figure 7B As shown, the battery string assembly 10 provided in this embodiment of the present invention may further include: an insulating pad 16 extending along a second direction, the insulating pad 16 being disposed between the first intermediate busbar 13 and the battery cell corresponding to the first intermediate busbar 13, and the insulating pad 16 being disposed between the second intermediate busbar 14 and the battery cell corresponding to the first intermediate busbar 13.

[0052] For example, targeting Figure 2 The first intermediate busbar 13 and the second intermediate busbar 14 shown cross the edges of two adjacent battery cells. Figure 7A shown Figure 2 The schematic diagram of the cross-sectional structure of section F1-F1 corresponding to the first intermediate busbar 13 and the second intermediate busbar 14 is shown in the figure. Figure 7A The diagram exemplarily illustrates the relative relationships between the (N+1)th cell of the first battery column 11, the (N+1)th cell of the second battery column 12, the insulating strip 16, the first intermediate busbar 13, the second intermediate busbar 14, the first polarity solder strip 30, and the second polarity solder strip 40. Figure 7A It can be seen that, for the structure where the first intermediate busbar 13 spans the edges of the Nth and N+1th cells of the first battery array 11, the second polarity solder strip 40 of the Nth cell in the first battery array 11 is disconnected from the second polarity solder strip 40 of the N+1th cell in the first battery array 11, making... Figure 7AThe cross-section of the (N+1)th cell in the first battery column 11 shown does not reveal the second polarity solder strip 40. Furthermore, the first polarity solder strip 30 connecting the first polarity grid line of the Nth cell in the first battery column 11 and the first polarity grid line of the (N+1)th cell in the first battery column 11 is connected above the first intermediate busbar 13. An insulating strip 16 is provided below the first intermediate busbar 13 to isolate the first intermediate busbar 13 from the cell below and the second polarity solder strip 40. Correspondingly, the second intermediate busbar 14 spans the edges of the Nth cell and the (N+1)th cell in the second battery column 12. The second polarity solder strip 40 of the Nth cell in the second battery column 12 is connected to the first polarity solder strip 30 of the (N+1)th cell in the second battery column 12, thus connecting the Nth cell and the (N+1)th cell in the second battery column 12 in series. Figure 7A The cross-section of the N+1th cell in the second battery column 12 shown in the diagram reveals the first polarity solder strip 30 located between the N+1th cell and the insulating strip 16. Furthermore, the second polarity solder strip 40 connecting the second polarity grid line of the N+2th cell in the second battery column 12 and the second polarity grid line of the N+1th cell in the second battery column 12 extends towards the second intermediate busbar 14, connecting with and above the second intermediate busbar 14. An insulating strip 16 is provided below the second intermediate busbar 14 to isolate the second intermediate busbar 14 from the Nth cell in the second battery column 12 below and the second polarity solder strip 40 thereon, as well as from the N+1th cell in the second battery column 12 and the first polarity solder strip 30 thereon.

[0053] For example, targeting Figure 3 The first intermediate busbar 13 shown is located on the back of the (N+1)th cell of the first battery column 11, and the second intermediate busbar 14 is located on the back of the (N+1)th cell of the second battery column 12. Figure 7B shown Figure 3 The schematic diagram of the cross-sectional structure of section F2-F2 corresponding to the first intermediate busbar 13 and the second intermediate busbar 14 is shown in the figure. Figure 7B The diagram exemplarily illustrates the relative relationships between the (N+1)th cell of the first battery column 11, the (N+1)th cell of the second battery column 12, the insulating strip 16, the first intermediate busbar 13, the second intermediate busbar 14, the first polarity solder strip 30, and the second polarity solder strip 40. Figure 7BAs can be seen, for the structure where the first intermediate busbar 13 is located on the back of the (N+1)th cell of the first battery column 11, the first polarity wire 30 connecting the first polarity grid line of the Nth cell of the first battery column 11 and the first polarity grid line of the (N+1)th cell of the first battery column 11 is connected above the first intermediate busbar 13. An insulating strip 16 is disposed between the first intermediate busbar 13 and the (N+1)th cell, so that the insulating strip 16 electrically isolates the first intermediate busbar 13 from the second polarity grid line of the (N+1)th cell of the first battery column 11 and from the second polarity grid line of the (N+1)th cell. The second polarity solder strip 40 is connected to the polarity grid line; correspondingly, the second intermediate busbar 14 is located on the back of the N+1th cell of the second battery column 12. The second polarity solder strip 40, which connects the second electrode grid line of the N+2th cell of the second battery column 12 and the second electrode grid line of the N+1th cell of the second battery column 12, extends above the second intermediate busbar 14. The insulating pad 16 extends below the second intermediate busbar 14 to electrically isolate the first polarity solder strip 30 (the first polarity solder strip 30 connects the first polarity grid line of the N+1th cell of the second battery column 12) from the second intermediate busbar 14.

[0054] Furthermore, the first cell of the first battery column 11 and the first cell of the second battery column 12 are connected in series via an edge busbar 15. Specifically, the second polarity grid line of the first cell of the first battery column 11 and the first polarity grid line of the first cell of the second battery column 12 are both connected to the edge busbar 15 via solder strips. The edge busbar 15 connects the first cell of the first battery column 11 and the first cell of the second battery column 12 in series, ultimately forming a first battery string by connecting the Nth cell to the first cell of the first battery column 11 and the first cell to the N+1th cell of the second battery column 12 in series. For example, as shown... Figures 2 to 4 As shown, the positive grid line of the first cell in the first battery column 11 is connected to an edge busbar 15 by a solder strip, and the negative grid line of the first cell in the second battery column 12 is connected to the edge busbar 15 by a solder strip, thereby realizing the series connection of the first cell in the first battery column 11 and the first cell in the second battery column 12.

[0055] The 2N+1th cell of the first battery column 11 and the 2N+1th cell of the second battery column 12 are connected in series by solder strips through another edge busbar 15. Specifically, the second polarity grid line of the 2N+1th cell of the second battery column 11 and the first polarity grid line of the 2N+1th cell of the second battery column 12 are both connected to the edge busbar 15 by solder strips. The edge busbar 15 enables the 2N+1th cell of the first battery column 11 and the 2N+1th cell of the second battery column 12 to be connected in series, ultimately forming a second battery string by connecting the N+1th to 2N+1th cells of the first battery column 11 and the 2N+1th to N+2th cells of the second battery column 12 in series. For example, as shown... Figures 2 to 4 As shown, the positive grid line of the 2N+1th cell of the first battery column 11 is connected to another edge busbar 15 by a solder ribbon, and the negative grid line of the 2N+1th cell of the second battery column 12 is connected to the other edge busbar 15 by a solder ribbon, thereby realizing the series connection of the 2N+1th cell of the first battery column 11 and the 2N+1th cell of the second battery column 12.

[0056] Two parallel current transmission circuits are obtained through the connection relationship of the battery string group 10 described above. The first current transmission circuit in the first battery string includes: the Nth to the 1st battery cell of the first battery column 11 and the 1st to the (N+1)th battery cell of the second battery column 12. The second current transmission circuit in the second battery string includes: the (N+1)th to the (2N+1)th battery cell of the first battery column 11 and the (2N+1)th to the (N+2)th battery cell of the second battery column 12. The first battery string includes 2N+1 battery cells connected in series, and the second battery string includes 2N+1 battery cells connected in series. The current transmission circuits in both the first and second battery strings contain 2N+1 battery cells, ensuring that the current transmission of the two parallel current transmission circuits is balanced.

[0057] It is worth noting that, since the solar cells are devices that provide electrical energy, the current flows from the negative grid line to the positive grid line inside the solar cell. Therefore, for the first battery string formed by connecting the Nth to the first solar cell of the first battery column 11 and the first to the N+1th solar cells of the second battery column 12, the current flow is as follows: the current flows from the negative grid line of the Nth solar cell of the first battery column 11 through the interior of the Nth solar cell to the positive grid line of the Nth solar cell. The positive grid line of the Nth solar cell then transmits the current to the negative grid line of the (N-1)th solar cell, and so on. The current in the negative grid line of one battery cell travels from the interior of the (N-1)th battery cell to the positive grid line of the (N-1)th battery cell, and so on. Current is transferred from the positive grid line of the second battery cell in the first battery column 11 to the negative grid line of the first battery cell in the first battery column 11. Current then travels from the negative grid line of the first battery cell in the first battery column 11 through the interior of that battery cell to the positive grid line of the first battery cell in the first battery column 11. The positive grid line of the first battery cell in the first battery column 11 then transmits the current to its connected edge busbar 15, which then transmits the current... The current flows from the negative grid line of the first cell in the second battery array 12 through the interior of the first cell to the positive grid line of the first cell in the second battery array 12. The positive grid line of the first cell in the second battery array 12 then transmits the current to the negative grid line of the second cell in the second battery array 12, and so on. The positive grid line of the Nth cell in the second battery array 12 transmits the current to the negative grid line of the (N+1)th cell in the second battery array 12. The current in the grid line is transmitted through the interior of the (N+1)th cell of the second battery column 12 to the positive grid line of the (N+1)th cell of the second battery column 12, and then reaches the second intermediate busbar 14 (i.e., the current flow direction of the first current transmission circuit: the Nth cell of the first battery column 11 → the (N-1)th cell of the first battery column 11 → ... → the 1st cell of the first battery column 11 → the edge busbar 15 connected to the 1st cell → the 1st cell of the second battery column 12 → the 2nd cell of the second battery column 12 → ... → the (N+1)th cell of the second battery column 12). Figure 2 and Figure 3 The current flow shown is to Y2 and Figure 4 The current shown flows to Y4.

[0058] For the second battery string formed by connecting the (N+1)th to (2N+1)th battery cells of the first battery column 11 and the (2N+1)th to (N+2)th battery cells of the second battery column 12, the current flow is as follows: the current flows from the negative grid line of the (N+1)th battery cell of the first battery column 11 through the interior of the (N+1)th battery cell to the positive grid line of the (N+1)th battery cell; the positive grid line of the (N+1)th battery cell transmits the current to the negative grid line of the (N+2)th battery cell; the current in the negative grid line of the (N+2)th battery cell flows through the interior of the (N+2)th battery cell to the positive grid line of the (N+2)th battery cell, and so on. The positive grid line of the 2Nth cell in the first battery column 11 transmits current to the negative grid line of the 2N+1th cell in the first battery column 11. The current in the negative grid line of the 2N+1th cell in the first battery column 11 is transmitted through the interior of the cell to the positive grid line of the 2N+1th cell in the first battery column 11. The positive grid line of the 2N+1th cell in the first battery column 11 transmits current to the edge busbar 15 to which it is connected. The edge busbar 15 transmits current to the negative grid line of the 2N+1th cell in the second battery column 12. The current in the negative grid line of the 2N+1th cell in the second battery column 12 is transmitted through the second battery column... The current is transmitted from the internal structure of the (2N+1)th cell of the second battery column 12 to the positive grid line of the (2N+1)th cell of the second battery column 12. The positive grid line of the (2N+1)th cell of the second battery column 12 then transmits the current to the negative grid line of the (2N)th cell of the second battery column 12, and so on. The positive grid line of the (N+3)th cell of the second battery column 12 transmits the current to the negative grid line of the (N+2)th cell of the second battery column 12. The current in the negative grid line of the (N+2)th cell of the second battery column 12 is transmitted through the internal structure of the (N+2)th cell of the second battery column 12 to the positive grid line of the (N+2)th cell of the second battery column 12. The current from the positive grid line of the (N+2)th cell in the second battery column 12 passes through the positive grid line of the (N+1)th cell in the second battery column 12 or the second polarity solder strip 40, and reaches the second intermediate busbar 14 (i.e., the current flow direction of the second current transmission circuit: the (N+1)th cell in the first battery column 11 → the (N+2)th cell in the first battery column 11 → ... → the (2N+1)th cell in the first battery column 11 → the edge busbar 15 connected to the (2N+1)th cell → the (2N+1)th cell in the second battery column 12 → the (2N)th cell in the second battery column 12 → ... → the (N+2)th cell in the second battery column 12). Figure 2 and Figure 3 The current flow shown is to Y1 and Figure 4 The current shown flows to Y3.

[0059] Regarding the battery string group 10 described above, the relative positional relationship between the first battery column 11 and the second battery column 12 can be such that the first battery column 11 is located on either the first side or the second side of the second battery column 12 in the width direction. For example, as shown... Figures 2 to 6 As shown, the width direction of the second battery array 12 is S1-S2, where the side corresponding to S1 is the first side of the width direction of the second battery array 12, and the side corresponding to S2 is the second side of the width direction of the second battery array 12, as shown. Figure 2 , Figure 3 and Figure 5 As shown, the first battery column 11 is located on the first side of the second battery column 12 in the width direction S1-S2. Figure 4 and Figure 6 As shown, the first battery column 11 is located on the second side of the second battery column 12 along the width direction S1-S2. The relative positional relationship between the first battery column 11 and the second battery column 12 affects the current flow direction. By flexibly arranging the relative positional relationship between the first battery column 11 and the second battery column 12, the needs of the battery string group 10 in different layout scenarios can be met, which is more conducive to the promotion of the battery string group 10.

[0060] Preferably, the aforementioned solar cells are generally back-contact structure solar cells, that is, solar cells cut from back-contact solar cells. It can be understood that... Figures 2 to 6 The back of the battery cell is shown in both images.

[0061] In this embodiment of the present invention, the first battery column 11 and the second battery column 12 in the battery string group 10 both contain an odd number of battery cells. The Nth battery cell to the first battery cell of the first battery column 11, the edge busbar 15, and the first battery cell to the (N+1)th battery cell of the second battery column 12 are connected in series to form the first battery string. The (N+1)th battery cell to the (2N+1)th battery cell of the first battery column 11, the edge busbar 15 on the other side, and the (2N+1)th to the (N+2)th battery cells of the second battery column 12 are connected in series to form the second battery string. The Nth cell of the first battery column 11 and the N+1th cell of the first battery column 11 are connected in parallel via solder ribbon and connected to the first intermediate busbar 13. The N+1th cell of the second battery column 12 and the N+2th cell of the second battery column 12 are connected in parallel via solder ribbon and connected to the second intermediate busbar 14. This allows the second intermediate busbar 14 to be located in the extension direction of the first intermediate busbar 13, enabling the bypass diode 20 connected in parallel in the battery string group 10 to connect an odd number of cells in parallel, thus better balancing the reverse voltage of the bypass diode 20 and the series loss of the battery string. Furthermore, the second intermediate busbar 14 of the battery string group 10 is located in the extension direction of the first intermediate busbar 13, aligning the second intermediate busbar 14 and the first intermediate busbar 13. This avoids introducing flying wires and ensures the appearance consistency of the battery string group 10 and the photovoltaic module containing the battery string group 10.

[0062] Furthermore, a battery string group 10 is formed by an odd number of battery cells forming a first battery column 11 and an odd number of battery cells forming a second battery column 12. The Nth and N+1th battery cells of the first battery column 11 are connected in parallel and connected to the first intermediate busbar 13, and the N+1th and N+2th battery cells of the second battery column 12 are connected in parallel and connected to the second intermediate busbar 14. With the help of the edge busbar 15, the first to Nth battery cells of the first battery column 11 and the first to N+1th battery cells of the second battery column 12 are connected in series to form a first battery string, and the N+1th to 2N+1th battery cells of the first battery column 11 and the N+2th to 2N+1th battery cells of the second battery column 12 are connected in series to form a second battery string. That is, the first battery string and the second battery string are still 2N+1 battery cells connected in series, which effectively reduces the series loss, avoids the breakdown problem of the bypass diode 20, and increases the efficiency of the battery string group 10.

[0063] Furthermore, in the aforementioned battery string group 10, the spacing between adjacent battery cells in each battery column can be 0 or negative (i.e., there is edge overlap between adjacent battery cells). This utility model provides an exemplary example. Figures 2 to 6 All descriptions assume the spacing between adjacent solar cells is 0.

[0064] Furthermore, there are various structures for the placement of the first intermediate busbar 13 and the second intermediate busbar 14.

[0065] Specifically, the first structure for the placement of the first intermediate busbar 13 and the second intermediate busbar 14 is as follows: Figure 2 and Figure 4 As shown, the first intermediate busbar 13 is disposed between the Nth and N+1th cells in the first battery array 11; the second intermediate busbar 14 is disposed between the Nth and N+1th cells in the second battery array 12. In this case, the second conductor connected to the second polarity grid line on the N+1th cell in the second battery array 12 extends to the space between the Nth and N+1th cells in the second battery array 12 to connect with the second intermediate busbar 14.

[0066] A second configuration for the placement of the first intermediate busbar 13 and the second intermediate busbar 14: The first intermediate busbar 13 is located on the back of the (N+1)th battery cell in the first battery array 11, and the second intermediate busbar 14 is located on the back of the (N+1)th battery cell in the second battery array 12. In this second configuration, the first intermediate busbar 13 and the second intermediate busbar 14 can be located at any position on the back of their respective (N+1)th battery cells. Preferably, as shown... Figure 3As shown, the first intermediate busbar 13 is disposed in the middle of the (N+1)th cell in the first battery column 11; the second intermediate busbar 14 is disposed in the middle of the (N+1)th cell in the second battery column 12. In this case, the first intermediate busbar 13 is only connected to the first polarity grid line on the back of the (N+1)th cell in the first battery column 11 or the first wire (i.e., the first polarity solder strip 30) connected to the first polarity grid line, and is insulated from the back of the (N+1)th cell in the first battery column 11 and the second polarity grid line or the solder strip connected to the second polarity grid line, for example, by being separated by an insulating gasket or insulating adhesive. Specifically, the first polarity grid line on the back of the (N+1)th cell in the first battery column 11, or the first conductor connected to the first polarity grid line, is located above the first intermediate busbar 13 and directly contacts the first intermediate busbar 13 to form an electrical connection. The back of the (N+1)th cell in the first battery column 11 and the second polarity grid line or the solder ribbon connected to the second polarity grid line are both located below the first intermediate busbar 13 and are electrically insulated by insulating adhesive. Similarly, the second intermediate busbar 14 is only connected to the second polarity grid line on the back of the (N+1)th cell in the second battery column 12, or the second conductor connected to the second polarity grid line (i.e., the second polarity solder ribbon 40), and is insulated from the back of the (N+1)th cell in the second battery column 12 and the first polarity grid line or the solder ribbon connected to the first polarity grid line, for example, by being separated by an insulating gasket or insulating adhesive. Specifically, the second polarity grid line on the back of the N+1th cell in the second battery column 12, or the second conductor connected to the second polarity grid line, is located above the second intermediate busbar 14 and is in direct contact with the second intermediate busbar 14 to form an electrical connection. The back of the N+1th cell in the second battery column 12 and the first polarity grid line or the solder strip connected to the first polarity grid line are both located below the second intermediate busbar 14 and are electrically insulated by insulating glue.

[0067] By using the various configurations of the first intermediate busbar 13 and the second intermediate busbar 14, the requirements of different photovoltaic module types (such as the position of the lead hole of the backplane 70 and the position of the bypass diode 20) can be met, so that the battery string group 10 can better meet the needs of different photovoltaic module types.

[0068] Furthermore, such as Figures 2 to 6 As shown, the battery string group 10 further includes: a first polarity solder strip 30 connected to the first polarity grid line of the Nth battery cell and the first polarity grid line of the (N+1)th battery cell of the first battery column 11; and a first intermediate busbar 13 connected to the first polarity solder strip 30. The first polarity solder strip 30 facilitates the connection between the first polarity grid line of the Nth battery cell and the first polarity grid line of the (N+1)th battery cell of the first battery column 11, ensuring the reliability of the connection between the Nth battery cell and the (N+1)th battery cell of the first battery column 11.

[0069] Furthermore, such as Figures 2 to 6 As shown, the battery string group 10 further includes: a second polarity solder strip 40 connected to the second polarity grid lines of the (N+1)th and (N+2)th battery cells of the second battery column 12; and a second intermediate busbar 14 connected to the second polarity solder strip 40. The second polarity solder strip 40 facilitates the connection between the second polarity grid lines of the (N+1)th and (N+2)th battery cells of the second battery column 12, ensuring the reliability of the connection between the (N+1)th and (N+2)th battery cells of the second battery column 12.

[0070] More specifically, for a cell size of 182mm × 94mm, the number of cells in both the first cell column 11 and the second cell column 12 is 25. By controlling the number of cells in both the first cell column 11 and the second cell column 12 to 25, the threshold of the directional voltage of the bypass diode 20 can be met, the cost of the bypass diode 20 can be controlled, and the series loss of the cell string can be effectively reduced.

[0071] Furthermore, this embodiment of the present invention also provides a photovoltaic module. The photovoltaic module may include one or more battery string groups 10 provided in any of the above embodiments. For example, as... Figure 5 and Figure 6 As shown, the photovoltaic module includes multiple battery string groups 10 provided in any of the above embodiments, such as... Figure 5 The photovoltaic module shown includes Figure 2 The battery string group 10 shown, Figure 6 The photovoltaic module shown includes Figure 4 The cell string group 10 is shown. Generally, a photovoltaic module contains only one type of cell string group 10 to ensure the direction of current transmission and the balance of current transmission. Figure 2 and Figure 4 They belong to two different battery string groups 10, therefore Figure 2 The battery string group 10 shown and Figure 4 The battery string group 10 shown is generally not in the same photovoltaic module.

[0072] Specifically, such as Figure 5 and Figure 6 As shown, in the case where a photovoltaic module includes multiple battery string groups 10, adjacent battery string groups 10 are connected in series.

[0073] More specifically, in a photovoltaic module, the arrangement order of the first cell column 11 and the second cell column 12 of multiple cell strings 10 can be two.

[0074] The first arrangement order of the first battery column 11 and the second battery column 12 of the multiple battery string groups 10 is as follows: Figure 5 and Figure 8 As shown, in a specific direction perpendicular to the extension direction of the battery string (i.e., the width direction S1-S2 of the second battery column 12 shown in the figure), the first battery column 11 and the second battery column 12 of the multiple battery string groups 10 are arranged alternately from left to right in the order of first battery column 11 first and second battery column 12 last; for each two adjacent battery string groups 10, the second intermediate busbar 14 of one battery string group 10 is adjacent to and connected to the first intermediate busbar 13 of the other battery string group 10, so that the two adjacent battery string groups 10 are connected in series.

[0075] The second arrangement order of the first battery column 11 and the second battery column 12 of the multiple battery string groups 10: as follows Figure 6 As shown, in a specific direction perpendicular to the extension direction of the battery string (i.e., the width direction S1-S2 of the second battery column 12 shown in the figure), the first battery column 11 and the second battery column 12 of the multiple battery string groups 10 are arranged alternately from left to right in the order of second battery column 12 first and first battery column 11 last; for each two adjacent battery string groups 10, the second intermediate busbar 14 of one battery string group 10 is adjacent to and connected to the first intermediate busbar 13 of the other battery string group 10, so that the two adjacent battery string groups 10 are connected in series.

[0076] Understandably, Figure 5 and Figure 6 This illustration only provides an example of the relative positions and connections of the individual cell strings in a photovoltaic module, as well as the connection between the bypass diode 20 and each cell string. Other components of the photovoltaic module... Figures 8 to 12 As shown.

[0077] To clearly illustrate the connections between battery string groups 10 Figure 8 It shows along Figure 5 A cross-sectional view along line AA in the extension direction of the first intermediate confluence zone 13 and the second intermediate confluence zone 14, from Figure 8 As can be seen, in the alternating arrangement of the first battery column 11 of the first battery string group, the second battery column 12 of the first battery string group, the first battery column 11 of the second battery string group, the second battery column 12 of the second battery string group, and the first battery column 11 of the third battery string group, the second intermediate bus 14 connected to the second battery column 12 of the first battery string group is connected to the first intermediate bus 13 connected to the first battery column 11 of the second battery string group; the second intermediate bus 14 connected to the second battery column 12 of the second battery string group is connected to the first intermediate bus 13 connected to the first battery column 11 of the third battery string group.

[0078] Figure 9 Show Figure 5A cross-sectional view of the battery string extension direction along line BB of the first battery column 11 in the middle; Figure 10 Show Figure 5 A cross-sectional view along line CC in the direction of extension of the battery string of the first battery column 11 in the middle; Figure 11 out Figure 5 A cross-sectional view of the second battery column 12 along the DD line in the battery string extension direction; Figure 12 Show Figure 5 A cross-sectional view along the line EE in the battery string extension direction of the 12th battery string in the middle; from Figures 9 to 12 The connection relationships between the cells in the first battery column 11 and between the cells in the second battery column 12 can be clearly seen.

[0079] from Figure 9 It can be seen that the second polarity grid line of the Nth cell in the first battery column 11 and the second polarity grid line of the (N+1)th cell in the first battery column 11 are electrically isolated; from Figure 10 It can be seen that the first polarity grid line of the Nth cell in the first battery column 11 and the first polarity grid line of the N+1th cell in the first battery column 11 are connected by the first polarity solder strip 30. Furthermore, from... Figure 9 and Figure 10 It can also be seen that the second polarity grid line of the first cell of the first battery column 11 is connected to an edge busbar 15 by a solder strip, and the second polarity grid line of the 2N+1th cell of the first battery column 11 is connected to another edge busbar 15 by a solder strip.

[0080] from Figure 11 It can be seen that the second intermediate busbar 14 is located between the Nth and N+1th cells of the second battery column 12. The second polarity grid line of the Nth cell of the second battery column 12 is electrically connected to the first polarity grid line of the N+1th cell of the second battery column 12. Simultaneously, the second polarity grid line of the Nth cell of the second battery column 12 and the first polarity grid line of the N+1th cell of the second battery column 12 are electrically isolated from the second intermediate busbar 14 by the insulating strip 16. Figure 12 It can be seen that the second polarity grid line of the (N+1)th cell of the second battery column 12 and the second polarity grid line of the (N+2)th cell of the second battery column 12 are connected by the second polarity solder strip 40. Furthermore, from... Figure 11 and Figure 12 It can also be seen that the first polarity grid line of the first cell of the second battery column 12 is connected to an edge busbar 15 by a solder strip, and the first polarity grid line of the 2N+1th cell of the second battery column 12 is connected to another edge busbar 15 by a solder strip.

[0081] Furthermore, such as Figure 5 and Figure 6As shown, the photovoltaic module also includes a bypass diode 20 connected in parallel to each cell string 10, wherein different bypass diodes 20 are connected in parallel to each cell string 10. That is, one bypass diode 20 manages two current circuits, reducing the number of bypass diodes 20 and ensuring that the current circuits do not affect each other.

[0082] Furthermore, such as Figures 8 to 12 As shown, the photovoltaic module may also include: a cover plate 50, an encapsulating film 60, and a back sheet 70, wherein the encapsulating film 60 is used to encapsulate the battery string group 10 between the cover plate 50 and the back sheet 70.

[0083] Furthermore, such as Figures 8 to 12 As shown, the photovoltaic module may further include an insulating strip 16 disposed between the first intermediate busbar 13 and the solar cell and between the second intermediate busbar 14 and the solar cell. In addition, the insulating strip 16 may also be disposed between the edge busbar 15 and the solar cell.

[0084] Furthermore, this utility model embodiment provides a method for preparing a battery string assembly. This method may include the following steps:

[0085] Step A1: Connect the first to the Nth battery cells of the first battery column 11 in series, connect the N+1th to the 2N+1th battery cells in series, connect the first to the N+1th battery cells of the second battery column 12 in series, and connect the N+2th to the 2N+1th battery cells in series.

[0086] Step A2: Pre-weld the first intermediate busbar 13 to M spaced-apart solder strips to form a first connection structure, pre-weld the second intermediate busbar 14 to K spaced-apart solder strips to form a second connection structure, and pre-weld the edge busbar 15 to M+K spaced-apart solder strips to form a third connection structure, where M equals K.

[0087] Step A3: Connect the M spaced-apart solder ribbons included in the first connection structure to the first polarity grid line of the Nth cell and the first polarity grid line of the N+1th cell in the first battery column 11; connect the K spaced-apart solder ribbons included in the second connection structure to the second polarity grid line of the N+1th cell and the second polarity grid line of the N+2th cell in the second battery column 12; connect the K spaced-apart solder ribbons included in a third connection structure to the second polarity grid line of the first cell in the first battery column 11 and connect the M spaced-apart solder ribbons to the first polarity grid line of the first cell in the second battery column 12; connect the K spaced-apart solder ribbons included in another third connection structure to the second polarity grid line of the 2N+1th cell in the first battery column 11 and connect the M spaced-apart solder ribbons to the first polarity grid line of the 2N+1th cell in the second battery column 12, thereby forming the battery string group provided in any of the above embodiments.

[0088] Based on existing stringing processes, the above-described battery string assembly method first forms a first connection structure, a second connection structure, and a third connection structure through step A2. This facilitates the positioning and establishment of connections between the first intermediate busbar 13, the second intermediate busbar 14, and the edge busbar 15 and the battery cells, simplifying the battery string assembly connection process, facilitating industrial production, and improving connection reliability.

[0089] Furthermore, this embodiment of the invention also provides a first method for manufacturing a photovoltaic module. This first method for manufacturing a photovoltaic module may include the method described above for manufacturing battery string arrays.

[0090] Furthermore, this embodiment of the invention also provides a second method for manufacturing a photovoltaic module. This second method for manufacturing a photovoltaic module may include the following steps:

[0091] Step B1: Sequentially lay the cover plate 50 and the upper sealing film;

[0092] Step B2: Arrange the battery cells on the upper encapsulation film, and connect the first to the Nth battery cells of the first battery column 11, the N+1th to the 2N+1th battery cells of the first battery column 11, and the first to the N+1th and the N+2th to the 2N+1th battery cells of the second battery column 12 in series. All the battery cells of the first battery column 11 are in the same column, and all the battery cells of the second battery column 12 are in the same column.

[0093] Step B3: Pre-weld the first intermediate busbar 13 to M spaced-apart solder strips to form a first connection structure; pre-weld the second intermediate busbar 14 to K spaced-apart solder strips to form a second connection structure; and pre-weld the edge busbar 15 to M+K spaced-apart solder strips to form a third connection structure, where M equals K.

[0094] Step B4: Connect the M spaced-apart solder ribbons included in the first connection structure to the first polarity grid line of the Nth cell and the first polarity grid line of the (N+1)th cell in the first battery array 11; connect the K spaced-apart solder ribbons included in the second connection structure to the second polarity grid line of the (N+1)th cell and the second polarity grid line of the (N+2)th cell in the second battery array 12; connect the K spaced-apart solder ribbons included in a third connection structure to the second polarity grid line of the first cell in the first battery array 11 and connect the M spaced-apart solder ribbons to the first polarity grid line of the first cell in the second battery array 12; connect the K spaced-apart solder ribbons included in another third connection structure to the second polarity grid line of the (2N+1)th cell in the first battery array 11 and connect the M spaced-apart solder ribbons to the first polarity grid line of the (2N+1)th cell in the second battery array 12.

[0095] Furthermore, the second method for preparing the photovoltaic module may further include, after step B4: sequentially stacking and covering the lower encapsulating film and the backsheet 70 on the cell array formed in step B4, and then performing a lamination process to form an encapsulating film 60 from the upper encapsulating film and the lower encapsulating film.

[0096] The method for manufacturing this photovoltaic module combines the series connection process between the cells with the connection between the first intermediate busbar 13, the second intermediate busbar 14 and the edge busbar 15 and the cells, realizing a manufacturing process from cells directly to photovoltaic modules. This eliminates the separate cell string manufacturing process, simplifies the manufacturing process, and effectively improves the reliability of the connection between cells.

[0097] Furthermore, the photovoltaic module manufacturing method, by first forming a first connection structure, a second connection structure, and a third connection structure, can conveniently locate and establish the connection between the first intermediate busbar 13, the second intermediate busbar 14, and the edge busbar 15 and the solar cell, simplifying the connection process between the solder strip and the busbar, which helps to achieve industrialized production and improve connection reliability.

[0098] Furthermore, this embodiment of the invention also provides a third method for manufacturing photovoltaic modules. Specifically, this third method may include the following steps:

[0099] Step C1: Sequentially lay the cover plate 50 and the upper sealing film;

[0100] Step C2: Arrange the battery string group 10 provided in any of the above embodiments on the upper encapsulation film;

[0101] Step C3: Sequentially lay the lower encapsulation film and backing plate to form a laminate;

[0102] Step C4: Laminate the laminated components to form a photovoltaic module.

[0103] The photovoltaic module prepared by this method contains 2N+1 cells in its cell string, which can better balance the reverse voltage of the bypass diode in the photovoltaic module and the series loss of the cell string in the photovoltaic module. Furthermore, it can avoid introducing flying wires in the photovoltaic module and ensure the appearance consistency of the photovoltaic module.

[0104] The structure provided by this utility model embodiment is described in detail below with reference to a specific example. Exemplarily, using... Figure 5 Taking N=12 as an example, 2N+1 is 25, meaning that each battery string and each battery column contains 25 battery cells. The first intermediate busbar 13 and the second intermediate busbar 14 are both located between the 12th and 13th battery cells in the battery column. In the odd-numbered columns (i.e., the 1st, 3rd, and 5th columns from left to right), the first intermediate busbar 13 connects the negative electrode solder strips of the 12th and 13th battery cells; the corresponding negative electrode solder strips of the battery cells (the 1st or 25th battery cell); in the even-numbered columns (i.e., the 2nd, 4th, and 6th columns from left to right), only the positive electrode solder strip of the 13th battery cell is connected to the second intermediate busbar 14, and the positive electrode solder strips of the 13th and 14th battery cells are connected to each other to form a parallel relationship. In this way, all intermediate busbars (first intermediate busbar 13 and second intermediate busbar 14) are aligned with each other, and the number of batteries in the parallel battery rows on both sides is the same, 25 each. This facilitates the installation of the junction box and eliminates the need for flying wires. Furthermore, to ensure insulation and conceal the busbars on the back of the batteries, the busbars and their connected solder strips are located on one side of the insulating strip 16, while the battery cells and solder strips not connected to the busbars are located on the other side of the insulating strip 16. A junction box with a bypass diode 20 is installed between adjacent first intermediate busbars 13 and second intermediate busbars 14. In this embodiment, the photovoltaic module has dimensions of 2382mm*1134mm and the cover glass has dimensions of 2376mm*1128mm, both of which are standard sizes. The cell size is 182mm*94mm, the cell spacing is 0mm, and the string length is 2350mm. Through testing, it was found that the short-side creepage distance of the photovoltaic module is 13.5mm, the long-side creepage distance is 13mm, and the measured power of the photovoltaic module is 666W, which is about 12W higher than the conventional 210R-66 model.

[0105] In this embodiment, it is preferred that each bypass diode 20 is connected in parallel with two battery strings (each battery string contains 25 cells). This is because when the number of cells in a battery string is greater than 25, the bypass diode 20 will experience thermal breakdown, leading to a short circuit in the parallel circuit. Furthermore, when the number of cells in a battery string is greater than 25, the hot spot temperature of the photovoltaic module cells will significantly increase, and when it exceeds 200°C, delamination of the encapsulant film from the backsheet is likely to occur. Additionally, when the number of cells in a battery string is less than 25, the cell size will increase for the same module design, resulting in increased cell current, increased string losses, and reduced power. Therefore, for a photovoltaic module with a size of 2382mm*1134mm, it is preferred that the battery string contains 25 cells. For the 2382mm*1134mm photovoltaic module provided in this embodiment, the test results for short-circuit current, module power, hot spot temperature, and thermal breakdown performance under different numbers of cells in the battery string and the same cell efficiency are shown in Table 1 below.

[0106]

[0107] As can be clearly seen from Table 1, as the size of the solar cells decreases, the number of solar cells in each string increases, the short-circuit current decreases, the module power is significantly improved, and the hot spot temperature of the module gradually increases. When the number of solar cells in each string reaches 26, the bypass diode is prone to thermal breakdown. However, when the number of solar cells in each string reaches 25, the module power is improved, and the bypass diode connected to the photovoltaic module will not experience thermal breakdown.

[0108] The above steps are provided only to help understand the method, structure, and core idea of ​​this utility model. For those skilled in the art, various improvements and modifications can be made to this utility model without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this utility model.

Claims

1. A battery string, characterized in that, include: The first battery pack (11), the second battery pack (12), the first intermediate busbar (13), the second intermediate busbar (14), and the two edge busbars (15). Both the first battery column (11) and the second battery column (12) contain 2N+1 battery cells arranged along the first direction, where N is a positive integer; In the first battery array (11), the first polar grid line of the Nth battery cell and the first polar grid line of the N+1th battery cell are connected by a first wire extending along the first direction, the first battery cell to the Nth battery cell are connected in series, and the N+1th battery cell to the 2N+1th battery cell are connected in series. In the second battery array (12), the second polarity grid line of the N+1th battery cell and the second polarity grid line of the N+2th battery cell are connected by a second wire extending along the first direction. The first battery cell to the N+1th battery cell are connected in series, and the N+2th battery cell to the 2N+1th battery cell are connected in series. The polarities of the first polarity grid line and the second polarity grid line are opposite. The first intermediate busbar (13) extends along a second direction perpendicular to the first direction and is connected to the first conductor; the second intermediate busbar (14) extends along the second direction and is located in the extension direction of the first intermediate busbar (13) and is connected to the second conductor. The first cell of the first battery column (11) and the first cell of the second battery column (12) are connected in series by an edge busbar (15); The 2N+1th cell of the first battery column (11) and the 2N+1th cell of the second battery column (12) are connected in series by another edge busbar (15).

2. The battery string pack according to claim 1, characterized in that, The first intermediate busbar (13) is disposed between the Nth battery cell and the (N+1)th battery cell in the first battery column (11); The second intermediate busbar (14) is disposed between the Nth and N+1th battery cells in the second battery array (12). The second wire in the second battery pack (12) extends to the second intermediate busbar (14) and connects to the second intermediate busbar (14).

3. The battery string pack according to claim 1, characterized in that, The first intermediate busbar (13) is located at the center of the back side of the (N+1)th battery cell in the first battery array (11). Wherein, the first intermediate busbar (13) contacts the first wire on the N+1th battery cell in the first battery column (11) and an insulating strip is provided between the N+1th battery cell in the first battery column (11) and the second polarity grid line of the N+1th battery cell; The second intermediate busbar (14) is located at the center of the back side of the (N+1)th cell in the second battery array (12). The second intermediate busbar (14) contacts the second wire on the N+1th cell in the second battery column (12) and is provided with an insulating strip between the N+1th cell in the second battery column (12) and the first polar grid line of the N+1th cell.

4. The battery string pack according to claim 1, characterized in that, The battery cell is a back-contact battery cell.

5. A photovoltaic module, characterized by include: One or more battery string packs (10) according to any one of claims 1 to 4.

6. The photovoltaic module according to claim 5, characterized in that, In the case where the photovoltaic module includes multiple battery strings (10), The adjacent battery strings (10) are connected in series. in, In the second direction, the first battery column (11) and the second battery column (12) of the plurality of battery string groups (10) are arranged alternately in the order of first battery column (11) first and second battery column (12) second or second battery column (12) first and first battery column (11) second. For each pair of adjacent battery string groups (10), the second intermediate bus (14) of one battery string group (10) is adjacent to and connected to the first intermediate bus (13) of the other battery string group (10), so that the two adjacent battery string groups (10) are connected in series.

7. The photovoltaic module according to claim 5 or 6, characterized in that Also includes: Each of the battery string groups (10) is connected in parallel with a bypass diode (20), wherein different bypass diodes (20) are connected in parallel to each of the battery string groups (10).

8. The photovoltaic module of claim 5 or 6, wherein, Also includes: Cover plate (50), encapsulating film (60) and back plate (70), wherein, The encapsulating film (60) is used to encapsulate the battery string (10) between the cover plate (50) and the back plate (70).

Images