Photovoltaikmodul

Abstract

Photovoltaic module comprising three solar cell string groups connected in series, each of the solar cell string groups comprising four parallel solar cell strings (11), each of the solar cell strings (11) comprising a plurality of cut cells (111) and the plurality of cut cells (111) being quarter cells formed by cutting an entire solar cell; the three series-connected solar cell string groups are distributed along a first direction (X) and the cut cells (111) in each of the solar cell strings (11) are distributed along a second direction (Y); and a head section and an end section of each of the solar cell strings (11) are each connected to a busbar, wherein the busbar comprises a first busbar (12) located at two ends of the photovoltaic module along the second direction (Y), and a second busbar (13) located in a middle section of the photovoltaic module along the second direction (Y), and wherein the first busbar (12) is located on a rear surface of the photovoltaic module.

Description

TECHNICAL AREA

[0001] The present disclosure relates to the technical field of photovoltaic power generation, in particular a photovoltaic module. TECHNICAL BACKGROUND

[0002] Photovoltaic modules can convert solar radiation energy directly into electrical energy, primarily based on the photovoltaic effect of crystalline silicon. This means that when light quanta from sunlight are absorbed by semiconducting crystalline silicon, electron-hole pairs are created. When these electron-hole pairs reach a pn junction, which consists of p-type and n-type crystalline silicon, they are separated by an electric field on either side of the junction. When these electron-hole pairs are connected to an external load, a photocurrent is generated, and the electrical energy is delivered.

[0003] The photoelectric conversion efficiency of conventional photovoltaic modules is relatively low. Therefore, improving the photoelectric conversion efficiency of photovoltaic modules is a pressing problem that needs to be solved. SUMMARY

[0004] The present disclosure provides a photovoltaic module for improving the photoelectric conversion efficiency of the photovoltaic module.

[0005] One embodiment of the present disclosure provides a photovoltaic module comprising three series-connected solar cell string groups. Each solar cell string group comprises four parallel-connected solar cell strings. The solar cell string comprises a plurality of cut cells, wherein the cut cells are quarter cells formed by cutting a whole solar cell. The three series-connected solar cell string groups are distributed along a first direction, and the cut cells in each solar cell string are distributed along a second direction. A head section and a tail section of each of the solar cell strings are each connected to a busbar.The busbar comprises a first busbar located at two ends of the photovoltaic module along the second direction, and a second busbar located in a middle section of the photovoltaic module along the second direction, with the first busbar being located on a rear surface of the photovoltaic module.

[0006] In one or more embodiments, a first insulating element is provided between the first busbar and the cut cell.

[0007] In one or more embodiments, the photovoltaic module further comprises a bridge extending in the second direction. The bridge is connected to the first busbar and is located between adjacent solar cell string groups, and a second insulating element is provided between the bridge and the cut cell.

[0008] In one or more embodiments, the first insulating element and the second insulating element are integrally formed.

[0009] In one or more embodiments, the bridge comprises a first bridge that is not connected to the second busbar and a second bridge that is connected to the second busbar. The first bridge includes a first output end near the second busbar, and the first output end is provided with a first junction box. The second bridge includes a second output end near the second busbar, and the second output end is provided with a second junction box.

[0010] In one or more embodiments, the quarter cells formed by cutting the entire solar cell comprise two edge cells and two middle cells, and the cut cells in the solar cell string are the edge cells; or the cut cells in the solar cell string are the middle cells; or the cut cells in the solar cell string comprise both the edge cells and the middle cells.

[0011] In one or more embodiments, if the cut cells in the solar cell string include both the edge cells and the middle cells, the edge cells and the middle cells are arranged alternately.

[0012] In one or more embodiments, a length L of the cut cell satisfies: 180 mm ≤ L ≤ 220 mm, and a width W of the cut cells satisfies: 45 mm ≤ W ≤ 55 mm.

[0013] In one or more embodiments, the number n of cut cells contained in each solar cell string satisfies: 18 ≤ n ≤ 24.

[0014] In one or more embodiments, a distance d between adjacent cut cells in the solar cell string is satisfied to be: -0.5 mm ≤ d ≤ 1.0 mm.

[0015] According to the present disclosure, the cut cells in the solar cell string are changed from half cells to quarter cells, and an arrangement with three parallel quadruple strings is used to reduce the area of ​​the cut cells, reduce the power loss in each solar cell string, and avoid the reduction in the overall current of the photovoltaic module caused by the use of cut cells with a smaller area, thereby improving the photoelectric conversion efficiency of the photovoltaic module. Furthermore, the first busbar is located on the rear surface of the photovoltaic module, i.e.,along a thickness direction of the cut cells, whereby most of the projection of the first busbar on the solar cell string overlaps with it, thereby reducing the area fraction of the busbar in the photovoltaic module, increasing the area fraction of the solar cell string in the photovoltaic module and thus further improving the photoelectric conversion efficiency of the photovoltaic module.

[0016] It is understood that the above general description and the detailed description below serve only to illustrate the information and cannot limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic structural diagram of a photovoltaic module according to one or more embodiments of the present disclosure; Fig. 2 is a circuit diagram of the in Fig. 1 photovoltaic module shown; Fig. 3 is a schematic structure diagram of the in Fig. 1 Photovoltaic module shown, in which a bridge, a first insulating element and a second insulating element are not inserted and a first busbar is not folded to a rear surface of the photovoltaic module; Fig. 4 is a schematic structure diagram of a substructure of the in Fig. 1 of the photovoltaic module shown; Fig. 5 is a top view of a [unclear] in the Fig. 1. First exit end shown; Fig. 6 is a side view of the [image / description] in the Fig. 1. First starting point shown; Fig. 7 is a top view of a [unclear] in the Fig. 1. Second exit end shown; Fig. Figure 8 is a schematic structural diagram of an entire solar cell, cut into four cells; Fig. Figure 9 is a schematic structural diagram of a photovoltaic module according to one or more embodiments of the present disclosure, in which the first busbar has not yet been folded over to the rear surface of the cut cells; and Fig. 10 is a schematic structure diagram of the in Fig. 9 shown photovoltaic module, in which the first busbar is folded over to the rear surface of the cut cells. Reference symbol: 11 solar cell strings; 111 sliced ​​cells; 112 solder strips; 12 first busbar; 13 second busbar; 13a second connecting wire; 14 first bridge; 14a first connecting wire; 15 second bridge; 16 first insulating element; 17 second insulating element; 21 first bypass diode; 22 second bypass diode; 23 third bypass diode.

[0017] The drawings are included in the description and form part of it. They illustrate embodiments according to the present disclosure and, together with the description, serve to explain the principles of the present disclosure. DESCRIPTION OF THE EXECUTION FORMS

[0018] To better understand the technical solutions of the present disclosure, embodiments of the present disclosure are described in detail below in conjunction with the drawings.

[0019] It is clarified that the described embodiments represent only some, and not all, embodiments of the present disclosure. All other embodiments that are obtained by those skilled in the art in this field based on the embodiments in the present disclosure without creative effort fall within the scope of protection of the present disclosure.

[0020] The terms used in the embodiments of this disclosure serve only to describe specific embodiments and are not intended to limit the present disclosure. As used in the embodiments of this disclosure and the appended claims, the singular forms "a / an", "the", and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] It is understood that the term "and / or" used here merely describes an associative relationship that denotes an associated object, and that there can be three relationships, for example A and / or B, and that it can mean: only A, both A and B, and only B. Furthermore, the symbol " / " here generally means that the objects before and after the symbol represent an "or" relationship.

[0022] It should be noted that positional terms such as "on / over", "below / under", "left", and "right", which are described in embodiments of the present disclosure, are described with reference to the angles shown in the drawings and are not to be interpreted as limitations of the embodiments of the present disclosure. Furthermore, it should be understood in context that when an element is described as being "on / over" or "below / under" another element, it is possible that one element is directly "on / over" or "below / under" another element, or that it is "on / over" or "below / under" another element via an intermediate element.

[0023] Currently, a conventional photovoltaic module typically consists of six solar cell strings connected in series to form a solar cell string group, and then two solar cell string groups are connected in parallel (i.e., two parallel six-string arrangements). The cut cells in the solar cell string are half-cells, formed by cutting the entire solar cell, so the area of ​​the cut cell is relatively large. Each solar cell generates a relatively larger number of charge carriers, and the current in each solar cell string is relatively high. According to the relationship that the power loss of electrons in the transfer process is proportional to the square of the current, the losses of the photovoltaic module are relatively high.

[0024] Furthermore, both the head and end sections of the solar cell string are connected to a busbar to conduct the current within the string. Because the busbars are located at the head and end sections of the solar cell string, the area occupied by the solar cells within the photovoltaic module is relatively small, which affects the photoelectric conversion efficiency of the module.

[0025] Embodiments of the present disclosure provide a photovoltaic module. As described in Fig. 1 and Fig. As shown in Figure 2, the photovoltaic module comprises three series-connected solar cell string groups (a dashed box in Figure 2). Fig. Figure 1 shows one of the solar cell string groups). Each solar cell string group comprises four parallel-connected solar cell strings 11 (a dashed box in Fig. Figure 2 shows one of the solar cell strings 11). The solar cell string 11 comprises a plurality of cut cells 111, and the cut cells 111 are quarter cells formed by cutting the entire solar cell. The cut cells 111 in a solar cell string 11 are electrically connected via a solder strip 112.

[0026] The cut cells 111 in the solar cell string 11 use quarter cells instead of half cells, and an arrangement with three parallel quadruple strings is used to reduce the area of ​​the cut cells 111, reduce the power loss in each solar cell string 11 and avoid the reduction in the overall current of the photovoltaic module caused by using the cut cells 111 with a smaller area, thereby improving the photoelectric conversion efficiency of the photovoltaic module.

[0027] In some embodiments, the current of a single solar cell string 11 in the photovoltaic module of the present disclosure is half the current of a single solar cell string in the conventional photovoltaic module, compared to a conventional photovoltaic module which uses an arrangement with two parallel six-strings, thereby reducing 3 / 4 of the power loss of the single solar cell string 11 and increasing the total power of the photovoltaic module by at least 5 W.

[0028] To simplify the description, the first direction X is defined as the direction in which three series-connected solar cell string groups are arranged, the second direction Y as the direction in which the cut cells 111 are arranged in the solar cell string 11, and the third direction Z as the thickness direction of the cut cells 111. One end of the solar cell string 11 along the second direction Y is a head section of the solar cell string 11, and the other end of the solar cell string 11 is a tail section of the solar cell string 11.

[0029] Furthermore, both the head and tail sections of the solar cell string 11 are connected to a busbar via the solder strip 112. The busbar comprises: a first busbar 12 located at both ends of the photovoltaic module along the second direction Y, and a second busbar 13 located in the middle of the photovoltaic module along the second direction Y. The first busbar 12 is located on the rear surface of the photovoltaic module, and both the first busbar 12 and the second busbar 13 extend along the first direction X.The fact that the second busbar 13 is located in the center of the photovoltaic module along the second direction Y means that the second busbar 13 can be arranged on a center line of the photovoltaic module along the second direction Y, or at a position offset to the left or right of the photovoltaic module along the second direction Y. That is, the second busbar 13 is not located at either end of the photovoltaic module along the second direction Y.

[0030] The first busbar 12 is located on the rear surface of the photovoltaic module, i.e., along the third direction Z. Most of the projection of the first busbar 12 onto the solar cell string 11 overlaps with the solar cell string 11, thereby reducing the area fraction of the busbar within the photovoltaic module, increasing the area fraction of the solar cell string 11 within the photovoltaic module, and further improving the photoelectric conversion efficiency of the photovoltaic module. The rear surface of the photovoltaic module refers to the backlit area of ​​the photovoltaic module.

[0031] In some embodiments, such as in Fig. 1 and Fig. As shown in Figure 2, the four solar cell strings 11 in the solar cell string group are arranged in two configurations along the first direction X and the second direction Y. That is, the four solar cell strings 11 are arranged in two rows and two columns. For the sake of simplicity, the end of each solar cell string 11 distributed along the second direction Y is defined as the end section, and the end not facing the other solar cell strings 11 is defined as the head section. That is, the head sections of the solar cell strings 11 are all connected to the first busbar 12, and the end sections of the solar cell strings 11 are all connected to the second busbar 13.

[0032] As in Fig. As shown in Figure 3, two first busbars 12 are provided at both ends of the photovoltaic module along the second direction Y. One of the first busbars 12 is longer, and the other is shorter. The longer first busbar 12 is connected to the solar cell strings 11 in two solar cell string groups, and the shorter first busbar 12 is connected to the solar cell strings 11 in only one solar cell string group.

[0033] In some embodiments, two shorter first busbars 12, located at both ends of the photovoltaic module along the second direction Y, are connected to the same solar cell string 11.

[0034] Accordingly, three second busbars 13 are provided, and each second busbar 13 is connected to the solar cell strings 11 in a solar cell string group.

[0035] In some embodiments, the photovoltaic module further comprises a bridge extending along the second direction Y, and the bridge is connected to the busbar and is located between adjacent solar cell string groups. The bridge comprises a first bridge 14 and a second bridge 15. The first bridge 14 is connected to two longer first busbars 12 and not to the second busbar 13. The second bridge 15 is connected to two shorter first busbars 12 and also to the second busbar 13, which is located midway along the first direction X. Reference numeral 15 in the drawings denotes the bridges.

[0036] In some embodiments, the shorter first busbar 12 extends along the first direction X beyond the edge of the connected solar cell string group to facilitate the connection between the shorter first busbar 12 and the second bridge 15.

[0037] Furthermore, as in Fig. Figure 4 shows a first insulating element 16 provided between the first busbar 12 and the cut cells 111, and the width of the first insulating element 16 is greater than the width of the first busbar 12 to prevent the first busbar 12 and the cut cells 111 from contacting each other.

[0038] The bridge is generally a conductive metal strip. To prevent a short circuit caused by contact between the bridge and the cut cells 111, a second insulating element 17 is provided between the bridge and the cut cells 111. The width L1 of the second insulating element 17 is greater than the width L2 of the bridge to effectively prevent contact between the bridge and the cut cells 111, thereby improving the safety and reliability of the photovoltaic module. Reference numerals 16 and 17 in the drawings denote the first and second insulating elements, respectively.

[0039] In some embodiments, the width L2 of the bridge ranges from 4 mm to 8 mm and the thickness of the bridge ranges from 0.15 mm to 0.4 mm. If the width of the bridge is less than 4 mm and the thickness of the bridge is less than 0.15 mm, the cross-sectional area of ​​the bridge is relatively small, resulting in poor current-carrying capacity, so that the bridge cannot carry the current in the photovoltaic module. If the width L2 of the bridge is greater than 8 mm, the overlap area between the bridge and the cut cells 111 increases, and the risk of microcracks in the cut cells 111 due to the bridge may increase during lamination.If the photovoltaic module is a double-glass module, both sides of the cut cells 111 are configured to absorb sunlight, and an excessively wide bridge increases the shading of the cut cells 111, thus impairing the photoelectric conversion efficiency of the photovoltaic module. Therefore, the width L2 of the bridge can be 4 mm, 6 mm, 8 mm, etc. Along the first direction X, the distance between adjacent cut cells 111 is 1.6 mm, which is less than the width L2 of the bridge, so the bridge can be positioned on one side of the cut cells 111 in the thickness direction.If the bridge thickness is greater than 0.4 mm, the size of the bridge protruding from the cut cells 111 is larger, which increases the possibility of microcracks in the cut cells 111 caused by pressure on the bridge during lamination, and also increases the possibility of bridge deformation, causing the bridge to contact the cut cells 111 and resulting in a short circuit. Therefore, the bridge thickness can be 0.15 mm, 0.3 mm, 0.4 mm, etc.

[0040] In some embodiments, the difference between the width L1 of the second insulating element 17 and the width L2 of the bridge satisfies the condition: 6 mm ≤ L1-L2 ≤ 10 mm. For example, the difference L1-L2 can specifically be: 6 mm, 6.5 mm, 7 mm, 8 mm, 9 mm, 9.5 mm, 10 mm, etc.

[0041] The difference L1-L2 should be neither too large nor too small. If the difference L1-L2 is too small (e.g., less than 6 mm), the bridge tends to shift out of the second insulating element 17, and the second insulating element 17 cannot prevent the bridge from contacting the cut cells 111. If the difference L1-L2 is too large (e.g., greater than 10 mm), the width L1 of the second insulating element 17 is larger, resulting in higher material costs. Therefore, the difference L1-L2 should be within a reasonable range.

[0042] In some embodiments, the thickness h1 of the second insulating element 17 satisfies the condition: 0.2 mm ≤ h1 ≤ 0.5 mm. For example, the thickness h1 of the second insulating element 17 can specifically be: 0.2 mm, 0.25 mm, 0.3 mm, 0.4 mm, 0.45 mm, 0.5 mm, etc.

[0043] The thickness h1 of the second insulating element 17 should be neither too large nor too small. If the thickness h1 of the second insulating element 17 is too small (e.g., less than 0.2 mm), its strength and reliability will be reduced, and it will be easily damaged by external forces, resulting in ineffective prevention of contact between the bridge and the cut cells 111. If the thickness h1 of the second insulating element 17 is too large (e.g., greater than 0.5 mm), its cost will be higher. Therefore, the thickness h1 of the second insulating element 17 should be within a reasonable range.

[0044] In some embodiments, the second insulating element 17 can comprise an insulating layer and an adhesive layer. The insulating layer can be made of polyethylene terephthalate (PET), and the adhesive layer can be made of ethylene vinyl acetate copolymer (EVA).

[0045] The width, thickness and material of the first insulating element 16 can be identical to those of the second insulating element 17, so that the first insulating element 16 and the second insulating element 17 can be cut from the same batch of roll material.

[0046] In some other embodiments, the width, thickness or material of the first insulating element 16 may be identical or different from those of the second insulating element 17.

[0047] Furthermore, the first insulating element 16 and the second insulating element 17 are integrally formed, so that in the assembly of the photovoltaic module the first insulating element 16 and the second insulating element 17 can be attached together to the cut cells 111, thereby simplifying the steps for assembling the photovoltaic module.

[0048] It is understood that the first insulating element 16 and the second insulating element 17 can also be arranged in a split configuration, so that when mounting the photovoltaic module, the first insulating element 16 and the second insulating element 17 are each attached to the cut cells 111 and a part of the first insulating element 16 overlaps a part of the second insulating element 17 to ensure the insulating effect of the position where the first insulating element 16 and the second insulating element 17 are located close together on the first busbar 12.

[0049] The first insulating element 16, which is arranged at one end of the photovoltaic module along the second direction Y, can be a single piece or multiple pieces. If the first insulating element 16 consists of multiple pieces, each piece of the first insulating element 16 corresponds to a solar cell string group.

[0050] In the above embodiments, the length L of the cut cell 111 satisfies: 180 mm ≤ L ≤ 220 mm, and the width W of the cut cell 111 satisfies: 45 mm ≤ W ≤ 55 mm, so that the strand length of the solar cell strand 11 formed by the cut cells 111 can comply with the creepage distance required by the photovoltaic module, thereby ensuring the normal use of the photovoltaic module, and bringing the size of the photovoltaic module formed by the arrangement with four parallel triple strands close to the size of the photovoltaic module formed by the two parallel six-strand arrangements, thus enabling the photovoltaic module in embodiments of the present disclosure to be manufactured or assembled without special processes or steps, thereby reducing production costs.

[0051] In the embodiments described above, the position where the first bridge 14 and the second busbar 13 are located close to each other is defined as the first output end, and the position where the second bridge 15 and the second busbar 13 are located close to each other is defined as the second output end. A first junction box is provided at the first connection wire end, and the two second busbars 13 and the first bridge 14 are connected to the first junction box. A second junction box is provided at the second connection wire end, and a second busbar 13 and the second bridge 15 are connected to the second junction box. The first junction box and the second junction box are connected to an external device.

[0052] In some embodiments, such as in Fig. 5 and Fig. As shown in Figure 6, the first bridge 14 includes a first connecting wire 14a at the first output end, and the second busbar 13 includes a second connecting wire 13a at the first output end. The two second connecting wires 13a and one first connecting wire 14a are arranged in a triangular pattern.

[0053] In some embodiments, such as in Fig. As shown in Figure 7, the second bridge 15 and the connected second connecting wire 13 share a third connecting wire (not shown in the drawing) at the second output end, and the second connecting wire 13, which is not connected to the second bridge 15, has a fourth connecting wire (not shown in the drawing). The third and fourth connecting wires are spaced apart along the first direction X.

[0054] In the above embodiments, the first busbar 12 can be folded towards the rear surface of the photovoltaic module. As in Fig. 1 and Fig. As shown in Figure 3, the head section of the solar cell string 11 is first connected to the first busbar 12 via the solder strip 112, and the end section of the solar cell string 11 is connected to the second busbar 13 via the solder strip 112. Then, the first insulating element 16 is attached to the rear surface of the photovoltaic module, and the first busbar 12 is folded over to the rear surface of the photovoltaic module using a tool. At this point, the first insulating element 16 is located between the first busbar 12 and the cut cells 111.

[0055] If the solder strip 112 connected to the first busbar 12 extends from the front surface of the photovoltaic module to the first busbar 12, the solder strip 112 is connected to a side of the first busbar 12 facing the cut cells 111. At this point, the first busbar 12 can protect the connection between the first busbar 12 and the solder strip 112. If the solder strip 112 connected to the first busbar 12 extends from the rear surface of the photovoltaic module to the first busbar 12, the solder strip 112 is connected to a side of the first busbar 12 away from the cut cells 111, so that the radius at the bend point of the solder strip 112 is relatively large, which makes the solder strip 112 less prone to breakage.To prevent the thickness of the solder strip 112 from being too great, which would lead to a heavy load on the cut cells 111 during lamination, the solder strip 112 can be inclined relative to the second direction Y, so that the solder strip 112 before folding and the solder strip 112 after folding do not overlap in the third direction Z.

[0056] It is understood that the first busbar 12 can also be arranged directly on the rear surface of the photovoltaic module and that the first busbar 12 contacts the solder strip 112 by forming holes in the first insulating element 16 corresponding to the solder strip 112, so that the first busbar 12 is electrically connected to the cut cells 111 and thus the first busbar 12 does not need to be folded.

[0057] In the above embodiments, the photovoltaic module comprises, as shown Fig. Figure 2 shows a first bypass diode 21, a second bypass diode 22, and a third bypass diode 23. For the sake of simplicity, the following are shown in Figure 2: Fig. Figure 2 defines a first solar cell string group, a second solar cell string group, and a third solar cell string group from left to right. The first solar cell string group is connected in reverse direction in parallel to the first bypass diode 21 via the first bridge 14, the second solar cell string group is connected in reverse direction in parallel to the second bypass diode 22 via the first bridge 14, and the third solar cell string group is connected in reverse direction in parallel to the third bypass diode 23 via the second bridge 15.

[0058] In some embodiments, the first bypass diode 21 is connected in reverse parallel to the first solar cell string group via the first bridge 14 (i.e., the first bypass diode 21 is connected in parallel to the first solar cell string group, but with opposite polarity). If one of the cut cells 111 on the solar cell string 11 in the first solar cell string group is blocked or fails, resulting in a hot-spot effect (i.e.,Some cut cells 111 in the photovoltaic module have a short-circuit current due to blockage, cracks or other reasons which is below the operating current of the module, so that these cut cells 111 are in a blocking state and consume the energy generated in other areas), the first bypass diode 21 can form a forward voltage so that the current bypasses the blocked or failed solar cell string 11 and flows through the first bypass diode 21 without affecting the normal current generation of other solar cell strings 11 in the first solar cell string group.

[0059] The second bypass diode 22 is connected in parallel with the second solar cell string group via the first bridge 14 in the opposite direction (i.e., the second bypass diode 22 is connected in parallel with the second solar cell string group, but with opposite polarity). If a cut cell 111 on the solar cell string 11 in the second solar cell string group is blocked or fails, resulting in a hot-spot effect, the second bypass diode 22 can form a forward bias so that the current bypasses the blocked or failed solar cell string 11 and flows through the second bypass diode 22 without affecting the normal current generation of the other solar cell strings 11 in the second solar cell string group.

[0060] The third bypass diode 23 is connected in parallel with the third solar cell string group via the second bridge 15 in the opposite direction (i.e., the third bypass diode 23 is connected in parallel with the third solar cell string group, but with opposite polarity). If a cut cell 111 on the solar cell string 11 in the third solar cell string group is blocked or fails, resulting in a hot-spot effect, the third bypass diode 23 can form a forward bias so that the current bypasses the blocked or failed solar cell string 11 and flows through the third bypass diode 23 without affecting the normal current generation of the other solar cell strings 11 in the third solar cell string group.

[0061] Furthermore, the number of cut cells 111 is the same in the first solar cell string group, the second solar cell string group and the third solar cell string group, so that the number of cut cells 111 is the same in the three solar cell string groups, which means that the number of cut cells 111 protected by the three bypass diodes is the same, which can improve the working stability of the three bypass diodes and further improve the protective effect of the three bypass diodes on the photovoltaic module.

[0062] In the embodiments described above, the number n of cut cells 111 contained in each solar cell string 11 satisfies the condition: 18 ≤ n ≤ 24. For example, the number n can specifically be 18, 19, 21, 22, 23, 24, etc. The number n of cut cells 111 contained in each solar cell string 11 should be neither too large nor too small. If the number of cut cells 111 in each solar cell string 11 is too small (e.g., less than 18), the overall size of the photovoltaic module is relatively small, making it impossible to assemble with conventional photovoltaic module production equipment, thus reducing the effective light absorption area of ​​the photovoltaic module. If the number of cut cells 111 in each solar cell string 11 is too large (e.g. more than 24), the overall size of the photovoltaic module is relatively large, so that it cannot be assembled with the conventional production device for photovoltaic modules.

[0063] Furthermore, in the solar cell string 11, the distance d between adjacent cut cells 111 satisfies the condition: -0.5 mm ≤ d ≤ 1.0 mm. The distance d can, for example, be -0.5 mm, -0.2 mm, 0.0 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, etc.

[0064] If the distance d between adjacent cut cells 111 is negative, the adjacent cut cells 111 partially overlap, so that there is no gap between them. This increases the area fraction of the cut cells 111 in the photovoltaic module, further increasing the effective light absorption area and improving the photoelectric conversion efficiency of the photovoltaic module. In some embodiments, the adjacent cut cells 111 can be welded together using a shingle sealing technology.

[0065] If the distance d between adjacent cut cells 111 is 0, the adjacent cut cells 111 lie next to each other, so that there is no gap between the cut cells 111, thereby increasing the area fraction of the cut cells 111 in the photovoltaic module, further increasing the effective light absorption area in the photovoltaic module and improving the photoelectric conversion efficiency of the photovoltaic module.

[0066] If the distance d between adjacent cut cells 111 is greater than 0, a gap exists between the adjacent cut cells 111. Therefore, the distance d should not be too large (e.g., not greater than 1.0 mm) to prevent the area fraction of the cut cells 111 in the photovoltaic module from becoming too small, which would result in a relatively small effective light absorption area in the photovoltaic module.

[0067] In the above-mentioned embodiments, as in Fig. As shown in Figure 8, the quarter cells formed by cutting the entire solar cell comprise two edge cells 111a and two center cells 111b. Some of the corners of the edge cells 111a are chamfered, and the four corners of the center cells 111b are right angles.

[0068] In some embodiments, the area S of a single chamfer at the edge cell 111a satisfies the following condition: 0.5 mm 2 ≤S≤10 mm 2 For example, the area S can specifically be 0.5 mm². 2 , 0.8 mm 2 , 1.0 mm 2 , 2.0 mm 2 , 5 mm 2 , 8 mm 2 , 9 mm 2 , 10 mm 2 etc.

[0069] The area S of the individual chamfer at the edge cell 111a should be neither too large nor too small. If the area S of the individual chamfer is too large (e.g., greater than 10 mm) 2), the light-receiving area of ​​the cut cells 111 is relatively small, which impairs the photoelectric conversion efficiency of the photovoltaic module. If the area S of the individual bevel is too small (e.g., less than 0.5 mm²) 2 The stress concentration cannot be effectively reduced, leading to microcracks or cracks in the solar cell. Therefore, the area S of the individual chamfer on the edge cell 111a should be within a reasonable range.

[0070] In some embodiments, the cut cells 111 in the solar cell string 11 are the edge cells 111a. Since the edge cells 111a have fewer cut edges and less damage, the photovoltaic module formed by the solar cell strings created by connecting the edge cells 111a has a higher photoelectric conversion efficiency. In some embodiments, the cut cells 111 in the solar cell string 11 are the middle cells 111b, thereby reducing waste resulting from not using the middle cells 111b. In some embodiments, the cut cells 111 in the solar cell string 11 include both the edge cells 111a and the middle cells 111b, further reducing storage pressure and cut cell waste when many edge cells 111a or many middle cells 111b are arranged.

[0071] In some embodiments, the solar cell strings 11 in the solar cell string group are all solar cell strings 11 formed by connecting the edge cells 111a. In some embodiments, the solar cell strings 11 in the solar cell string group are all solar cell strings 11 formed by connecting the middle cells 111b. The solar cell strings 11 in the solar cell string group comprise both the solar cell strings 11 formed by connecting the edge cells 111a and the solar cell strings 11 formed by connecting the middle cells 111b, and the two are arranged alternately.

[0072] If the cut cells 111 in the solar cell string 11 include both the edge cells 111a and the middle cells 111b, the edge cells 111a and the middle cells 111b are arranged alternately, thus facilitating the arrangement and linking of the cells. It is understood that the edge cells 111a and the middle cells 111b of the solar cell string 11 can also be distributed randomly or according to other rules.

[0073] In the embodiments described above, the types of cut cells 111 include, among others, passivated emitter backside cells (PERC), tunnel oxide passivated contact (TOPCON), heterojunctions with intrinsic thin film (HIT), perovskite solar cells (PSC), etc. The embodiments described in the present disclosure do not specifically limit the types of cut cells 111 in the photovoltaic module.

[0074] In the TOPCON solar cell, the cell comprises, sequentially along its thickness, a metal-silver electrode, a silicon nitride passivation layer on the front surface, a boron-doped emitter, an N-type substrate silicon layer, a diffusion doping layer, an ultrathin silicon oxide layer, doped polysilicon, a silicon nitride layer, and a metal-silver electrode. The rear surface of the solar cell consists of a layer of ultrathin silicon oxide (1 nm to 2 nm) and a layer of phosphor-doped microcrystalline amorphous mixed silicon film, which together form a passivated contact structure. This structure can prevent minority carrier and hole recombination, thereby increasing the open-circuit voltage and short-circuit current of the solar cell. The ultrathin oxide layer can block minority electron and hole recombination while simultaneously allowing many electrons to tunnel into a polysilicon layer.A good passivation effect of the ultrathin silicon oxide and a heavily doped silicon layer causes a curvature of the surface energy band of a silicon wafer, resulting in a field passivation effect that significantly increases the probability of electron tunneling, reduces the contact resistance and improves the open-circuit voltage and short-circuit current of the solar cell, thereby improving the conversion efficiency of the solar cell.

[0075] In the HIT solar cell, the HIT solar cell comprises, along its thickness, a front low-temperature silver electrode, a front conductive film, an N-type amorphous silicon layer, an intrinsic amorphous silicon film, an N-type silicon layer as a substrate, an intrinsic amorphous silicon film, a P-type amorphous silicon film, a rear conductive film, and a rear low-temperature silver electrode.

[0076] In the PERC solar cell, the PERC solar cell comprises, sequentially along its thickness, a front metal-silver electrode, a front silicon nitride passivation layer, a phosphor layer emitter, a P-type substrate silicon layer, a local aluminum back field, a metal-aluminum back electrode, and a rear passivation layer (Al2O3 / SiN). x In the PERC solar cell, a passivation layer is used to passivate the rear surface and replace a back field made entirely of aluminum, thereby improving the internal back reflection of light on a silicon substrate, reducing the recombination rate on the rear surface and increasing the efficiency of the solar cell by 0.5% to 1%.

[0077] In a PSC solar cell, the perovskite solar cell comprises, along its thickness, a substrate material, a conductive film, an electron transport layer (titanium dioxide), a perovskite absorption layer (hole transport layer), and a metal cathode. The perovskite material has a relatively high light absorption coefficient and a relatively long charge carrier diffusion distance. After the photons absorbed by the perovskite are converted into electrons, the electrons can be easily collected by an electrode with lower loss, generating a relatively high photovoltage and photocurrent. Thus, the perovskite solar cell exhibits a relatively high photoelectric conversion efficiency.

[0078] In some embodiments, such as in Fig. 9 and Fig. As shown in Figure 10, the type of cut cell 111 is a Back Contact (BC).

[0079] In the BC solar cell, an emitter, a surface field, and a metal electrode are arranged on the rear surface of the solar cell and distributed interdigitally. The front surface of the solar cell is coated with a SiN x / SiO x -Provided with a double-layer anti-reflection passivation layer so that the front surface of the solar cell is not shielded by the metal electrode, allowing the solar cell to receive more incident light, reducing optical loss and improving photoelectric conversion efficiency.

[0080] Since the metal electrodes of the BC solar cell are all located on the rear surface of the cut cells 111, the solder strips 112, which connect the cut cells 111 and the first busbar 12, are also located on the rear surface of the cut cells 111, and the solder strips 112 are connected to a side of the first busbar 12 that is away from the cut cells 111, so that the solder strips 112 have a larger radius at a bending point, which makes the solder strips 112 less likely to break.

[0081] In some embodiments, the cut cell 111 is a tandem solar cell comprising an upper solar cell, an interleaved layer, and a lower solar cell. The interleaved layer is connected to and located between the lower and upper solar cells. The upper solar cell can be a perovskite solar cell, a cadmium telluride solar cell, a copper indium gallium selenide solar cell, or a gallium arsenide solar cell. The lower solar cell can be a PERC solar cell, a TOPCON solar cell, a HIT solar cell, or a BC solar cell. The interleaved layer can be selected from a transparent, high-refractive-index material, such as a transparent conductive metal oxide (ITO) film.An effective intermediate layer must have high light transmittance to reduce reflection and absorption of light at the interface of the layer, as well as good conductivity to reduce the influence of series resistance on the performance of the device.

[0082] The above descriptions are only preferred embodiments of the present disclosure and are not intended to limit the present disclosure, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement, and the like made within the scope of and in accordance with the present disclosure shall fall within the scope of protection of the present disclosure.

Claims

[1] Photovoltaic module comprising three solar cell string groups connected in series, each of the solar cell string groups comprising four solar cell strings (11) connected in parallel, each of the solar cell strings (11) comprising a plurality of cut cells (111) and the plurality of cut cells (111) being quarter cells formed by cutting an entire solar cell; the three series-connected solar cell string groups are distributed along a first direction (X) and the cut cells (111) in each of the solar cell strings (11) are distributed along a second direction (Y); and a head section and an end section of each of the solar cell strings (11) are each connected to a busbar, wherein the busbar comprises a first busbar (12) located at two ends of the photovoltaic module along the second direction (Y), and a second busbar (13) located in a middle section of the photovoltaic module along the second direction (Y), and wherein the first busbar (12) is located on a rear surface of the photovoltaic module. [2] Photovoltaic module according to claim 1, wherein a first insulating element (16) is provided between the first busbar (12) and the cut cell (111). [3] Photovoltaic module according to claim 2, further comprising a bridge extending in the second direction (Y), wherein the bridge is connected to the first busbar (12) and is located between adjacent solar cell string groups, and wherein a second insulating element (17) is provided between the bridge and the cut cell (111). [4] Photovoltaic module according to claim 3, wherein the first insulating element (16) and the second insulating element (17) are integrally formed. [5] Photovoltaic module according to claim 3, wherein the bridge comprises a first bridge (14) which is not connected to the second busbar (13) and a second bridge (15) which is connected to the second busbar (13); and the first bridge (14) comprises a first output end near the second busbar (13) and the first output end is provided with a first junction box; and the second bridge (15) comprises a second output end near the second busbar (13) and the second output end is provided with a second junction box. [6] Photovoltaic module according to claim 1, wherein the quarter cells formed by cutting the entire solar cell comprise two edge cells (111a) and two middle cells (111b), and wherein the cut cells (111) in the solar cell string (11) are the edge cells (111a); or the cut cells (111) in the solar cell string (11) are the middle cells (111b); or the cut cells (111) in the solar cell string (11) include both the edge cells (111a) and the middle cells (111b). [7] Photovoltaic module according to claim 6, wherein, if the cut cells (111) in the solar cell string (11) comprise both the edge cells (111a) and the middle cells (111b), the edge cells (111a) and the middle cells (111b) are arranged alternately. [8] Photovoltaic module according to any one of claims 1 to 7, wherein a length L of the cut cell (111) satisfies the following condition: 180 mm ≤ L ≤ 220 mm, and a width W of the cut cell (111) satisfies the following condition: 45 mm ≤ W ≤ 55 mm. [9] Photovoltaic module according to one of claims 1 to 7, wherein a number n of the cut cells (111) contained in each solar cell string (11) satisfy the following condition: 18 ≤ n ≤ 24. [10] Photovoltaic module according to one of claims 1 to 7, wherein in the solar cell string (11) a distance d between adjacent cut cells (111) satisfies the following condition: -0.5 mm ≤ d ≤ 1.0 mm.

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