Battery string group, preparation method of battery string group and photovoltaic module

Abstract

The invention relates to the technical field of photovoltaic, and discloses a battery string group, a preparation method of the battery string group and a photovoltaic module, the battery string group comprises N groups of battery strings arranged in parallel, each battery string comprises a plurality of battery fragments arranged in series, the battery fragments are 1 / M battery pieces, N is greater than M, and M is greater than or equal to 2. Under the condition that the same number is needed for an array device, compared with photovoltaic modules prepared by N cutting M and photovoltaic modules prepared by N cutting N, the system voltage of the system is reduced by 27-29%, so that the probability of hot spot occurrence is reduced, the correspondingly compared photovoltaic module system voltage needs to be increased to 2000V, and the system voltage of the photovoltaic modules needs to be increased to 2000V, so that the system voltage of the photovoltaic modules needs to be increased to 2000V and the system voltage of the photovoltaic modules needs to be increased to 2000V and the system voltage of the photovoltaic modules needs to be increased to 2000V. According to the assembly with the 1500V system voltage, the effect similar to the 2000V system voltage of a compared photovoltaic assembly can be achieved.

Description

Technical Field

[0001] This application relates to the field of photovoltaic technology, and in particular to a battery string, a method for preparing the battery string, and a photovoltaic module. Background Technology

[0002] With the application and development of photovoltaics, cost reduction and efficiency improvement have always been constant themes. Multi-segment modules involve cutting a single cell into multiple smaller segments, such as 6-segment, 5-segment, or 4-segment cells, which are then connected in parallel. The typical parallel connection method is N-segment N-parallel; for example, a two-segment cell is a two-parallel design, and a 6-segment cell is a 6-parallel design. Currently, segmented cell module designs offer advantages such as low current and high-density packaging.

[0003] However, the photovoltaic modules currently produced by slitting have higher voltages, which makes them more prone to hot spots.

[0004] The information disclosed in the background section is only for enhancing the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] Based on this, a battery string assembly, a method for preparing the battery string assembly, and a photovoltaic module are provided. The battery string assembly can be used to further reduce the voltage of the photovoltaic module and reduce the probability of hot spots.

[0006] Therefore, in a first aspect, embodiments of this application provide a battery string group, including N sets of battery strings arranged in parallel, each battery string including multiple battery segments arranged in series, wherein each battery segment is 1 / M battery cells, and N is greater than M, and M is greater than or equal to 2.

[0007] In one embodiment, the number of battery segments in each battery string is less than or equal to 26.

[0008] In one embodiment, the system further includes a first busbar, a second busbar, and a third busbar. The first busbar is used to connect one end of the N sets of battery strings connected in parallel, the second busbar is used to connect the other end of the N sets of battery strings connected in parallel, and the third busbar is used to connect the first busbar and the second busbar.

[0009] In one embodiment, a fourth busbar is further included for connecting N sets of the battery strings arranged in parallel. The fourth busbar is located between the first busbar and the second busbar, and is arranged parallel to the first busbar and the second busbar. The fourth busbar is connected to the third busbar.

[0010] In one embodiment, the width of the first busbar gradually increases from both ends toward the connection point with the third busbar, and / or the width of the second busbar gradually increases from both ends toward the connection point with the third busbar; and / or the width of the fourth busbar gradually increases from both ends toward the connection point with the third busbar.

[0011] In one embodiment, at least two third busbars are provided, one of which is connected to the first busbar and the fourth busbar, and the other of which is connected to the second busbar and the fourth busbar, with the two third busbars being staggered.

[0012] In one embodiment, the battery cell is a rectangle with a side length of ≥182mm, and the voltage of the battery string gradually decreases as the side length of the battery cell gradually increases.

[0013] Secondly, embodiments of this application provide a method for preparing a battery string assembly as described in any of the above claims, wherein the method for preparing the battery includes: The battery cells are cut to obtain battery segments, which are 1 / M battery cells; Multiple battery segments are connected in series to form a battery string, and the number of battery strings is N, where N is greater than M and M is greater than or equal to 2. The N groups of batteries are connected in series and parallel.

[0014] In one embodiment, the battery cell is subjected to anti-cutting leakage treatment before cutting, and / or the battery cell is subjected to edge passivation treatment after cutting.

[0015] Thirdly, embodiments of this application provide a photovoltaic module, including a junction box and a battery as described above connected to the junction box, wherein the lead-out hole of the junction box is arranged perpendicularly to the cable.

[0016] According to the battery string group, battery string group preparation method, and photovoltaic module provided in the embodiments of this application, the battery string group includes N sets of battery strings arranged in parallel, and each battery string includes multiple battery cells arranged in series. Each battery cell is 1 / M cells, where N is greater than M, and M is greater than or equal to 2. When comparing the photovoltaic modules prepared by N-cut M-parallel configuration and those prepared by N-cut N-parallel configurations in an array, the system voltage of this application is 27-29% lower, thereby reducing the probability of hot spots. The corresponding photovoltaic module system voltage of the comparison needs to be increased to 2000V. The 1500V system voltage module of this application can achieve a similar effect to the 2000V system voltage of the comparison photovoltaic module. Attached Figure Description

[0017] Figure 1 This diagram illustrates the structure of the first type of battery string assembly provided in this application embodiment; Figure 2 This paper shows a circuit diagram of a battery string assembly provided in an embodiment of this application; Figure 3 This illustration shows a schematic diagram of the structure of a second type of battery string assembly provided in an embodiment of this application; Figure 4 This illustration shows a structural diagram of the third type of battery string assembly provided in an embodiment of this application; Figure 5 This illustration shows a schematic diagram of the structure of a first type of photovoltaic module provided in an embodiment of this application; Figure 6 This invention provides a schematic diagram of the structure of a fourth type of battery according to an embodiment of this application. Figure 7 This invention provides a schematic diagram of the structure of a second type of photovoltaic module according to an embodiment of the present application. Figure 8 This invention provides a schematic diagram of the structure of a third type of photovoltaic module according to an embodiment of the present application. Figure 9 This diagram illustrates the structure of the first type of junction box provided in this application embodiment; Figure 10 This diagram illustrates the structure of a second junction box provided in an embodiment of this application.

[0018] Explanation of reference numerals in the attached figures: 1. Battery string; 11. Battery segment; 2. First busbar; 3. Second busbar; 4. Third busbar; 5. Fourth busbar; 6. Junction box; 61. Lead wire hole. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0021] The structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0022] The orientations or positional relationships indicated by terms such as "upper," "lower," "left," "right," "middle," "longitudinal," "lateral," "horizontal," "inner," "outer," "radial," and "circumferential" used in this specification are based on the orientations or positional relationships shown in the accompanying drawings and are only for the purpose of simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0023] Multi-segment modules involve cutting a single cell into multiple smaller segments, such as 6-segment, 5-segment, or 4-segment modules, and then connecting them in parallel. The typical parallel connection method is N-segment N-parallel; for example, a two-segment module is a two-parallel design, and a 6-segment module is a 6-parallel design. Currently, multi-segment cell module designs offer advantages such as low current and high-density packaging. However, current multi-segment cell modules have higher voltages, which increases the risk of hot spots.

[0024] To solve the above problems, refer to Figures 1-3 , Figure 1 This diagram illustrates the structure of the first type of battery string assembly provided in this application embodiment. Figure 2 This paper shows a circuit diagram of a battery string assembly provided in an embodiment of this application; Figure 3 This diagram illustrates the structure of a second type of battery string assembly provided in an embodiment of this application.

[0025] This application provides a battery string group, including N sets of battery strings 1 connected in parallel. Each battery string 1 includes multiple battery segments 11 connected in series. Each battery segment 11 consists of 1 / M battery cells, where N is greater than M and M is greater than or equal to 2.

[0026] It's important to understand that battery segment 11 is a 1 / M battery cell, meaning a whole battery cell is cut into battery segments 11. Multiple battery segments are connected in series to form battery strings 1, and then N sets of battery strings 1 are connected in parallel to obtain the battery. Here, N is greater than M, and M is greater than or equal to 2. For example, M is 2, and N is 3, 4, or 5 sets.

[0027] In one example, with M = 4 and N = 6, the solar cells are cut to obtain four independent cell segments 11 of the same specifications. These cell segments 11 are connected in series to form six cell strings 1. The six cell strings 1 are then connected in parallel. Subsequent steps include encapsulant film laying, backsheet laying, EL testing, appearance inspection, lamination, framing, junction box installation, and other testing and manufacturing processes to complete the photovoltaic module fabrication. The photovoltaic module is tested, and its open-circuit voltage is approximately 38.3V. When M = 4 and N = 4, the photovoltaic module's open-circuit voltage is approximately 48.7V; when M = 6 and N = 6, the open-circuit voltage is approximately 50.1V.

[0028] When comparing photovoltaic modules prepared by N-cut M-parallel and N-cut N-parallel methods in an array with the same quantity required, the voltage of the modules prepared by this application is 27-29% lower. Furthermore, the system voltage of the photovoltaic modules prepared by this application is 1500V. Under the same conditions, the capacity of the installed module system is close to that of the existing system with a voltage increased to 2000V. The 1500V system voltage module of this application can achieve a similar effect to the 2000V system voltage of the compared photovoltaic modules.

[0029] In some alternative embodiments, the number of battery segments 11 in each battery string 1 is less than or equal to 26. When the number of battery segments 11 in the battery string 1 is greater than 26, the voltage is prone to being too high, making the diodes easily damaged.

[0030] In some optional embodiments, a first busbar 2, a second busbar 3, and a third busbar 4 are also included. The first busbar 2 is used to connect one end of N sets of parallel-connected battery strings 1, the second busbar 3 is used to connect the other end of the N sets of parallel-connected battery strings 1, and the third busbar 4 is used to connect the first busbar 2 and the second busbar 3. The arrangement of the first busbar 2, the second busbar 3, and the third busbar 4 can be used to connect multiple battery strings 1 in parallel. An insulating strip is provided below the first busbar 2 and the second busbar 3, and the first busbar 2 and the second busbar 3 are hidden on the back of the battery strings 1. The third busbar 4 integrates a diode to block "inter-string reverse discharge" and protect faulty battery strings 1.

[0031] Reference Figures 1-6 , Figure 4 This diagram illustrates the structure of the third type of battery string assembly provided in this application embodiment. Figure 5 This diagram illustrates the structure of the first type of photovoltaic module provided in this application embodiment. Figure 6 This diagram illustrates the structure of the fourth type of battery provided in an embodiment of this application.

[0032] In some optional embodiments, a fourth busbar 5 is also included for connecting N sets of parallel battery strings 1. The fourth busbar 5 is located between the first busbar 2 and the second busbar 3, and is arranged parallel to the first busbar 2 and the second busbar 3. The fourth busbar 5 is connected to the third busbar 4. Only one fourth busbar 5 may be provided, or multiple fourth busbars may be provided, depending on the number of battery segments 11. The provision of the fourth busbar 5 can increase the number of battery segments 11, while simultaneously balancing current or voltage and preventing local overload.

[0033] Reference Figures 4-7 , Figure 7 This diagram illustrates the structure of a second photovoltaic module according to an embodiment of this application. In some optional embodiments, the width of the first busbar 2 gradually increases from both ends toward the connection point with the third busbar 4; and / or, the width of the second busbar 3 gradually increases from both ends toward the connection point with the third busbar 4; and / or, the width of the fourth busbar 5 gradually increases from both ends toward the connection point with the third busbar 4. This arrangement results in lower resistance in the portions of the first busbar 2, the second busbar 3, and the fourth busbar 5 near the terminals of the third busbar 4, thereby reducing current conduction losses, reducing material usage, and facilitating increased output power.

[0034] Reference Figure 3 In some optional embodiments, at least two third busbars 4 are provided. One third busbar 4 is connected to the first busbar 2 and the fourth busbar 5, and the other third busbar 4 is connected to the second busbar 3 and the fourth busbar 5. The two third busbars 4 are staggered. The third busbars 4 have positions for leading out the positive and negative terminals. In one example, the fourth busbar 5 connected to the first busbar 2 has a position for leading out the positive terminal, and the fourth busbar 5 connected to the second busbar 3 has a position for leading out the negative terminal. The staggered arrangement of the two third busbars 4 ensures that at least one of the positive and negative terminal positions is not located in the middle of the battery, facilitating connection to the cable in the junction box. Compared to having the positive and negative terminal positions located in the middle of the battery, this arrangement reduces the amount of cable used.

[0035] Reference Figures 4-8 , Figure 8 This diagram illustrates the structure of a third type of photovoltaic module provided in an embodiment of this application. In one example, in one cell, the fourth busbar 5 connected to the first busbar 2 is located on the left side, and the fourth busbar 5 connected to the second busbar 3 is located on the right side. In another cell, the fourth busbar 5 connected to the first busbar 2 is located on the right side, and the fourth busbar 5 connected to the second busbar 3 is located on the left side. In some optional embodiments, the solar cells are rectangular with a side length ≥ 182mm, and the voltage of the battery string gradually decreases as the side length of the solar cells gradually increases. The solar cells can be square or rectangular, and this application does not impose any limitation. The side length of the solar cells can be 182mm*182mm, 182mm*190mm, 182mm*210mm, 210mm*210mm, etc., and this application does not impose any limitation.

[0036] In one example, when the cell dimensions are 182mm*182mm, the measured open-circuit voltage of a 4-cut, 6-parallel photovoltaic module is approximately 38.3V. In another example, when the cell dimensions are 210mm*210mm, the measured open-circuit voltage of a 4-cut, 6-parallel photovoltaic module is approximately 35.4V.

[0037] That is, with the same number of cuts and the same number of battery strings, the voltage gradually decreases as the size of the battery cells increases.

[0038] This application also includes a method for preparing a battery string assembly, comprising: Step 1: Cut the battery cell to obtain battery segment 11, which is a 1 / M battery cell; Step 2: Connect multiple battery segments 11 in series to form battery string 1. The number of battery strings 1 is N, where N is greater than M and M is greater than or equal to 2. Step 3: Connect N sets of batteries in series and then in parallel.

[0039] In step 1, the size of the battery cell is first selected, and then the battery cell is processed to prevent cutting and leakage. The battery cell is then laser-cut, and the edges of the battery cell are passivated after cutting to obtain M battery segments of the same specifications 11, where M is greater than or equal to 2. The batteries are sorted and tested according to requirements. Alternatively, the battery cells before cutting can be treated to prevent cutting and leakage, or the battery cells after cutting can be treated to passivate the edges. In step 2, multiple battery segments 11 are connected in series to form battery strings 1. The number of battery strings 1 is N, where N is greater than M.

[0040] In step 3, the battery string 1 is stacked according to the circuit layout of this application, and the corresponding first bus bar 2, second bus bar 3, third bus bar 4 and fourth bus bar 5 are set at the corresponding positions. The first bus bar 2, second bus bar 3, third bus bar 4 and fourth bus bar 5 can be set by welding, gluing or other methods. An insulating strip is set below the first bus bar 2 and second bus bar 3. The first bus bar 2 and second bus bar 3 are hidden on the back of the battery cell. The battery string 1 composed of N M-cut battery segments 11 is connected in parallel, and the number of battery segments 11 connected in series in each battery string 1 between two horizontal fourth bus bars 5 is less than or equal to 26.

[0041] The subsequent steps include film laying, backsheet laying, EL testing, appearance inspection, lamination, framing, junction box installation, and other testing and manufacturing steps to complete the component manufacturing.

[0042] Reference Figures 1-10 , Figure 9 This diagram shows a structural schematic of the first type of junction box provided in an embodiment of this application. Figure 10 This illustration shows a structural schematic of a second type of junction box provided in an embodiment of this application. This application also includes a photovoltaic module, which includes a junction box 6 and a battery string group as described above connected to the junction box 6. The lead-out hole 61 of the junction box 6 is arranged perpendicularly to the cable.

[0043] The battery comprises N sets of parallel-connected battery strings 1, each battery string 1 comprising multiple series-connected battery segments 11. Each battery segment 11 consists of 1 / M battery cells, where N is greater than M, and M is greater than or equal to 2. When comparing the photovoltaic modules prepared by N-cut M-parallel configuration and those prepared by N-cut N-parallel configurations in an array, the system voltage of the present application is 27-29% lower, thus reducing the probability of hot spots. Furthermore, while the system voltage of the photovoltaic modules in the present application remains unchanged at 1500V, the system voltage of the corresponding comparison photovoltaic modules needs to be increased to 2000V. The 1500V system voltage module of the present application achieves a similar effect to the 2000V system voltage of the comparison photovoltaic modules.

[0044] Among them, the lead-out hole 61 of the junction box 6 is set perpendicular to the cable to reduce the impact of cable bending stress.

[0045] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0046] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery string assembly, characterized in that, It includes N sets of parallel battery strings (1), each battery string (1) includes multiple battery segments (11) connected in series, each battery segment (11) is 1 / M battery cells, where N is greater than M and M is greater than or equal to 2.

2. The battery string pack according to claim 1, characterized in that, The number of battery segments (11) in each battery string (1) is less than or equal to 26.

3. The battery string pack according to claim 1, characterized in that, It also includes a first busbar (2), a second busbar (3) and a third busbar. The first busbar (2) is used to connect one end of the N sets of parallel battery strings (1), the second busbar (3) is used to connect the other end of the N sets of parallel battery strings (1), and the third busbar (4) is used to connect the first busbar (2) and the second busbar (3).

4. The battery string pack according to claim 3, characterized in that, It also includes a fourth busbar (5) for connecting N sets of the battery strings (1) in parallel. The fourth busbar (5) is located between the first busbar (2) and the second busbar (3). The fourth busbar (5) is arranged parallel to the first busbar (2) and the second busbar (3). The fourth busbar (5) is connected to the third busbar (4).

5. The battery string pack according to claim 4, characterized in that, The width of the first busbar (2) gradually increases from both ends toward the connection point with the third busbar (4); and / or, the width of the second busbar (3) gradually increases from both ends toward the connection point with the third busbar (4); and / or, the width of the fourth busbar (5) gradually increases from both ends toward the connection point with the third busbar (4).

6. The battery string pack according to claim 4 or 5, characterized in that, At least two third busbars (4) are provided. One third busbar (4) is connected to the first busbar (2) and the fourth busbar (5). Another third busbar (4) is connected to the second busbar (3) and the fourth busbar (5). The two third busbars (4) are staggered.

7. The battery string pack according to claim 1, characterized in that, The battery cell is a rectangle with a side length of ≥182mm, and the voltage of the battery string gradually decreases as the side length of the battery cell gradually increases.

8. A method for preparing a battery string assembly, characterized in that, The method for preparing the battery according to any one of claims 1-7 comprises: The battery cells are cut to obtain battery segments (11), and the battery segments (11) are 1 / M battery cells; Multiple battery segments (11) are connected in series to form a battery string (1), and the number of battery strings (1) is N, where N is greater than M and M is greater than or equal to 2. The N sets of battery strings (1) are connected in parallel.

9. The method for preparing a battery string according to claim 8, characterized in that, The battery cells are treated to prevent leakage during cutting before cutting; and / or, the battery cells are treated to passivate the edges after cutting.

10. A photovoltaic module, characterized in that, Includes a junction box (6) and a battery string assembly according to any one of claims 1-7 connected to the junction box (6), wherein the lead-out hole (61) of the junction box (6) is arranged perpendicular to the cable.

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