Photovoltaic module

Abstract

The invention relates to the photovoltaic field, in particular to a photovoltaic module, which comprises a plurality of battery strings, each battery string comprises a plurality of solar batteries arranged along a first direction, and each solar battery comprises a battery piece body and a plurality of bonding pads arranged on the battery piece body; the plurality of first bus bars extend along a second direction, and the plurality of first bus bars are respectively positioned at two opposite ends of the battery string and are electrically connected with the battery string; the at least one electric connecting piece extends along the first direction and is electrically connected with the two oppositely arranged first bus bars; wherein the battery piece body comprises a first area, the first area is an area, close to the connecting position of the first bus bar and the electric connecting piece, on the battery piece body, and in the first area, the area of at least one bonding pad is larger than the area of bonding pads located in other areas, except the first area, on the battery piece body; and the reliability and the manufacturing yield of the photovoltaic module can be improved at least.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of photovoltaics, and in particular to a photovoltaic module. BACKGROUND

[0002] With the rapid development of the photovoltaic industry, the structure design and manufacturing process of photovoltaic modules as the core components of solar power generation systems are constantly optimized. Currently, a photovoltaic module is usually formed by connecting multiple cell pieces in series through a welding band to form a cell string, and then connecting multiple cell strings in parallel / series through a busbar.

[0003] However, the mechanical stress generated by the deformation or displacement of the jumper during the packaging or use of the photovoltaic module will be transmitted to the busbar and the welding band connection area, damaging the stability of the welding interface and affecting the reliability of the photovoltaic module. SUMMARY

[0004] The present disclosure provides a photovoltaic module that can at least improve the reliability and manufacturing yield of the photovoltaic module.

[0005] In one aspect, the present disclosure provides a photovoltaic module, comprising: a plurality of cell strings, the cell string comprising a plurality of solar cells arranged along a first direction, the solar cell comprising a cell piece body and a plurality of pads disposed on the cell piece body; a plurality of first busbars, the plurality of first busbars extending along a second direction, the plurality of first busbars being respectively located at opposite ends of the cell string and electrically connected with the cell string; at least one electrical connector, the electrical connector extending along the first direction and electrically connected with two first busbars arranged opposite to each other; wherein the cell piece body comprises a first region, the first region being a region of the cell piece body close to a connection position of the first busbar and the electrical connector, and in the first region, an area of at least one pad is greater than an area of a pad in other regions of the cell piece body except the first region.

[0006] Optionally, the plurality of pads are arranged on the cell piece body along the first direction and the second direction; in the first region, along the first direction, the area of the pad close to the connection position is greater than the area of the pad away from the connection position, and along the second direction, the area of the pad close to the connection position is greater than the area of the pad away from the connection position.

[0007] Optionally, in the first region, along the first direction, the area ratio between two adjacent pads is greater than the area ratio between two adjacent pads along the second direction.

[0008] Optionally, the area ratio between two adjacent pads in the first direction is 0.90-0.99.

[0009] Optionally, the area ratio between two adjacent pads in the second direction is 0.80-0.95.

[0010] Optionally, the cell body comprises a second region, which is a region other than the first region on the cell body; in the second region, the pad area close to the first region is greater than the pad area away from the first region in the first direction, and the pad area close to the first region is greater than the pad area away from the first region in the second direction.

[0011] Optionally, the area ratio between two adjacent pads in the first direction in the first region is greater than the area ratio between two adjacent pads in the second region, and the area ratio between two adjacent pads in the second direction in the first region is greater than the area ratio between two adjacent pads in the second region.

[0012] Optionally, the area ratio between two adjacent pads in the first direction in the first region is 0.90-0.99, and the area ratio between two adjacent pads in the second direction in the first region is 0.80-0.95.

[0013] Optionally, the area ratio between two adjacent pads in the first direction in the first region is 0.90-0.99, and the area ratio between two adjacent pads in the second direction in the first region is 0.80-0.95.

[0014] Optionally, the area of the pad is 0.15mm²-1mm².

[0015] Optionally, the ratio of the width of the cell body in the second direction to the width in the first direction is 2-4.

[0016] The technical solutions provided by the present disclosure have at least the following advantages: The photovoltaic module provided by the present disclosure increases the contact area of the pad and the solder ribbon by designing the area of at least one pad in the first region, i.e., the region close to the connection position of the bus bar and the electrical connector, to be greater than the pad area in other regions, thereby improving the welding strength; thus, the stress transmitted to the bus bar due to the stretching or thermal deformation of the electrical connector can be effectively alleviated, the risk of solder ribbon detachment or virtual welding is reduced, and the reliability and manufacturing yield of the photovoltaic module are ultimately improved. BRIEF DESCRIPTION OF DRAWINGS

[0017] One or more embodiments are illustrated by way of example in the figures that form a part of this disclosure and which are shown by way of illustration in which like references indicate similar elements, and in which, unless otherwise specified, the figures are not necessarily drawn to scale. The figures depict one or more embodiments that can be implemented individually and independently from one another.

[0018] Figure 1 is a partial structure diagram of a conventional photovoltaic module in the prior art; Figure 2 is Figure 1 is an enlarged diagram of the position circled in the figure. In the conventional photovoltaic module, when a string of cell strings needs to be connected to a junction box through a long jumper 1, the other end of the long jumper 1 is welded on a busbar 2. In actual production and reliability testing, it is found that the long jumper 1 generates a continuous pulling force due to its own gravity, thermal expansion or mechanical stretching during lamination or subsequent use, which causes displacement of the busbar 2 connected thereto. Further, this displacement is directly transmitted to the solder strip 3 welded with the busbar, so that the solder joint bears additional shearing or peeling stress, which easily causes the solder strip 3 to be pulled off under the action of stress concentration, thereby causing virtual welding or even open circuit, which seriously affects the reliability of the photovoltaic module. Figure 3 is a structure diagram of a photovoltaic module provided by an embodiment of the present disclosure; Figure 4 is a partial structure diagram of a photovoltaic module provided by an embodiment of the present disclosure; Figure 5 is a partial structure diagram of another photovoltaic module provided by an embodiment of the present disclosure; Figure 6 is a partial structure diagram of still another photovoltaic module provided by an embodiment of the present disclosure.

[0019] Reference signs: long jumper 1, busbar 2, solder strip 3, cell string 20, first busbar 21, electrical connecting piece 22, solar cell 201, cell piece body 202, solder pad 203, first area 204, first sub-cell string 206, second sub-cell string 207, second busbar 24, second area 208. DETAILED DESCRIPTION

[0020] Reference Figure 1 and Figure 2 , Figure 1 is a partial structure diagram of a conventional photovoltaic module in the prior art; Figure 2 is Figure 1 is an enlarged diagram of the position circled in the figure. In the conventional photovoltaic module, when a string of cell strings needs to be connected to a junction box through a long jumper 1, the other end of the long jumper 1 is welded on a busbar 2. In actual production and reliability testing, it is found that the long jumper 1 generates a continuous pulling force due to its own gravity, thermal expansion or mechanical stretching during lamination or subsequent use, which causes displacement of the busbar 2 connected thereto. Further, this displacement is directly transmitted to the solder strip 3 welded with the busbar, so that the solder joint bears additional shearing or peeling stress, which easily causes the solder strip 3 to be pulled off under the action of stress concentration, thereby causing virtual welding or even open circuit, which seriously affects the reliability of the photovoltaic module.

[0021] To solve this problem, the industry usually considers increasing the welding area between the welding strip and the bus bar or using higher strength solder to improve the connection firmness. However, these methods may cause problems such as cost increase, process complexity increase, or heat damage to other areas; more importantly, the stress source is in the local stress concentration of the connection structure, and the traditional pad design cannot specifically cope with this local high stress area.

[0022] Based on the in-depth analysis of the above technical problems, the present disclosure provides a photovoltaic module, by increasing the pad area on the cell near the connection position of the bus bar and the electrical connector, thereby improving the welding strength in this area, effectively relieving the stress transmitted to the bus bar due to the stretching or thermal deformation of the electrical connector, reducing the risk of welding strip disconnection or false welding, and ultimately improving the reliability and manufacturing yield of the photovoltaic module.

[0023] In the description of the embodiments of the present disclosure, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present disclosure, the meaning of "multiple" is more than two, unless otherwise explicitly and specifically limited. Similarly, "multiple groups" means more than two groups (including two groups), and "multiple pieces" means more than two pieces (including two pieces).

[0024] In this document, the reference to "embodiments" means that the specific features, structures or properties described in connection with the embodiments can be included in at least one embodiment of the present disclosure. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. The skilled person explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0025] In the description of the embodiments of the present disclosure, the term "and / or" is only a description of the association relationship between the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists, A and B exist, and B exists. In addition, the character " / " in this document generally represents a "or" relationship between the front and rear associated objects.

[0026] In the description of the embodiments of the present disclosure, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience of describing the embodiments of the present disclosure and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present disclosure. For example, if the devices or elements in the drawings are inverted, the elements described as "under" or "below" or "under" or "bottom" of other elements or features will be oriented "above" or "top" of the other elements or features. Therefore, the term "under" can cover both upward and downward orientations depending on the context in which the term is used, which will be apparent to those skilled in the art. The materials can be oriented in other ways (e.g., rotated 90 degrees, inverted, flipped), and the spatially relative descriptions used herein can be interpreted accordingly.

[0027] In the description of the embodiments of the present disclosure, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium, or can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present disclosure can be understood according to the specific circumstances.

[0028] In the corresponding drawings of the embodiments of the present disclosure, the thickness and / or area of the layers, films, panels, regions, etc. are exaggerated for better understanding and ease of description. Throughout the specification, the same reference signs represent the same elements. It should be understood that when describing a component (such as a layer, film, region, or substrate) on or on the surface of another component, the component can be "directly" on the surface of the other component, or there can be an intermediate component between the two components. Conversely, when describing a component on the surface of another component, or a component "directly on" another component, or a component surface forming or provided with another component, it is meant that there is no intermediate component between the two components. In addition, when describing a component "formed substantially" on another component, it means that the component is not formed on the entire surface (or front surface) of the other component, nor on a portion of the edge of the entire surface.

[0029] In the description of the embodiments of the present disclosure, when a certain component "includes" another component, unless otherwise specified, other components are not excluded, and other components can be further included. A first component is formed or disposed above or on a second component, or a first component is formed or disposed on a surface of a second component, or a first component is formed or disposed on a side of a second component, which can include an embodiment in which the first component and the second component are in direct contact, and can also include an embodiment in which additional components can be between the first component and the second component, so that the first component and the second component can not be in direct contact. For simplicity and clarity, various components can be arbitrarily drawn in different proportions. In the drawings, some layers / components can be omitted for simplicity. As no specific description is given, a first component formed or disposed on a surface of a second component means that the first component is in direct contact with the second component. Among them, the "component" mentioned above can refer to a layer, a film, a region, a part, a structure, etc.

[0030] The terms used in the description of various described embodiments herein are only used to describe specific embodiments and are not intended to be limiting. As used in the description of various described embodiments and the appended claims, "the component" is also intended to include the plural, unless the context clearly indicates otherwise. Among them, the component includes layers, films, regions, or plates, etc.

[0031] The embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. However, those skilled in the art can understand that in the embodiments of the present disclosure, many technical details are proposed in order to enable the reader to better understand the present disclosure. However, the technical solutions claimed by the present disclosure can be implemented even without these technical details and based on various changes and modifications of the following embodiments.

[0032] Figure 3 The structural schematic diagram of the photovoltaic module provided by the embodiments of the present disclosure is shown.

[0033] Reference Figures 3 to 4 The photovoltaic module includes a plurality of cell strings 20, a plurality of first bus bars 21, and at least one electrical connection 22.

[0034] Specifically, the battery string 20 includes a plurality of solar cells 201 arranged along a first direction X, the solar cell 201 including a cell body 202 and a plurality of pads 203 disposed on the cell body 202; a plurality of first bus bars 21 extending along a second direction Y, the plurality of first bus bars 21 being respectively located at opposite ends of the battery string 20 and electrically connected with the battery string 20; and an electrical connector 22 extending along the first direction X and electrically connected with the two first bus bars 21 oppositely arranged; wherein the cell body 202 includes a first region 204, the first region 204 being a region of the cell body 202 close to a connection position of the first bus bar 21 and the electrical connector 22, and in the first region 204, an area of at least one pad 203 is greater than an area of a pad 203 in a region of the cell body 202 other than the first region 204.

[0035] A photovoltaic module is used to convert solar energy into electrical energy.

[0036] In some embodiments, the battery string 20 includes a solder strip for connecting adjacent solar cells 201.

[0037] The solar cell 201 can be one of a PERC (Passivated Emitter Rear Cell) cell, an IBC (Interdigitated Back Contact) cell, a TOPCON (Tunnel Oxide Passivated Contact) cell, a heterojunction cell, a solar thin film cell, and a stacked cell, or any combination thereof. The solar thin film cell includes, but is not limited to, a perovskite solar thin film cell, a copper-indium-selenium solar thin film cell, a gallium arsenide solar thin film cell, and a cadmium sulfide solar thin film cell. The stacked cell includes, but is not limited to, a perovskite cell stacked with a crystalline silicon cell, a perovskite cell stacked with a perovskite cell, and a perovskite cell stacked with a thin film cell.

[0038] The solar cell 201 can be a main grid cell, which can shorten the current conduction path, reduce internal loss, and thus improve the power of the photovoltaic module.

[0039] The present disclosure does not limit the number of solder points and grid lines. The number of transverse main grid lines can be 6, 8, etc., and the number of grid lines corresponding to the longitudinal solder points can be 10, 12, 14, 16, 18, 20, etc., which can be flexibly adjusted according to the actual cell design.

[0040] The solar cell 201 can also be a main grid-free cell, which uses a solder strip instead of the original main grid to directly connect with the fine grid, thereby greatly reducing the consumption of silver paste and thus reducing the cost of the photovoltaic module.

[0041] The battery string 20 includes a first sub-battery string 206 and a second sub-battery string 207 arranged along the first direction X. The first busbar is located on the side of the first sub-battery string away from the second sub-battery string, and also on the side of the second sub-battery string away from the first sub-battery string 206. The first busbar 21 is an end busbar for electrically connecting with the battery string 20.

[0042] The electrical connection 22 extends along the first direction X and is electrically connected with the first busbar 21.

[0043] It should be noted that the connection position of the electrical connection 22 and the first busbar 21 is a mechanical stress concentration area. When the electrical connection 22 is long, such as for connecting a remote terminal box, the stretching or deformation of the electrical connection 22 generated during lamination, handling or thermal cycling will be transmitted to the solder strip welded with the first busbar 21 through the first busbar 21, which is easy to cause the solder strip to be off-welded or false-welded.

[0044] Therefore, the area of the pad 203 in the first area on the battery piece body 202 corresponding to the connection position is increased to increase the contact area of the pad 203 and the solder strip, so as to improve the welding strength and avoid the solder strip being off-welded or false-welded.

[0045] In some embodiments, the photovoltaic module further includes a second busbar 24 located between the first sub-battery string 206 and the second sub-battery string 207 and electrically connected with the first sub-battery string 206 and the second sub-battery string 207.

[0046] The electrical connection 22 is electrically connected with the second busbar 24.

[0047] The connection position of the electrical connection 22 and the second busbar 24 is also a mechanical stress concentration area. Similarly, the area of the pad 203 in the first area on the battery piece body 202 corresponding to the connection position of the electrical connection 22 and the second busbar 24 can be increased to increase the contact area of the pad 203 and the solder strip, so as to improve the welding strength and avoid the solder strip being off-welded or false-welded.

[0048] The photovoltaic module provided by the present disclosure increases the area of at least one pad in the first area near the connection position of the busbar and the electrical connection of the battery piece, so as to increase the contact area of the pad and the solder strip, thereby improving the welding strength. Therefore, the stress transmitted to the busbar due to the stretching or thermal deformation of the electrical connection can be effectively alleviated, the risk of the solder strip being off-welded or false-welded is reduced, and the reliability and manufacturing yield of the photovoltaic module are ultimately improved.

[0049] The embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings.

[0050] ReferenceFigure 5 In some embodiments, the plurality of pads 203 are arranged along the first direction X and the second direction Y on the cell body 202; in the first area 204, along the first direction X, the pad 203 closer to the connection position has a larger area than the pad 203 farther away from the connection position, and along the second direction Y, the pad 203 closer to the connection position has a larger area than the pad 203 farther away from the connection position.

[0051] In other words, the pad 203 area in the first area 204 gradually decreases from the connection position outward, so that the area of the pad 203 closest to the connection point of the electrical connector 22 and the first bus bar 21, which is the area with the most concentrated stress, is provided with the largest welding contact area, thereby significantly enhancing the mechanical strength and tensile capacity of the local solder joint; at the same time, the gradient distribution of the pad 203 area avoids unnecessary material waste in the non-stress concentration area, effectively inhibits the problem of solder strip disconnection or false welding caused by the displacement of the first bus bar 21 due to the stretching of the electrical connector 22, and improves the manufacturing yield and long-term operation reliability of the assembly.

[0052] In some embodiments, in the first area 204, the area ratio between two adjacent pads 203 along the first direction X is greater than the area ratio between two adjacent pads 203 along the second direction Y.

[0053] Specifically, the change of the pad 203 area in the extension direction of the electrical connector 22 is relatively gentle, while the area gradient change in the extension direction of the first bus bar 21 is more significant.

[0054] Since the electrical connector 22 extends along the first direction X and is connected to the first bus bar 21, the tensile force generated by the electrical connector 22 is mainly conducted to the pad 203 along the first direction X, so in this direction, the gradient of the pad 203 area decreasing from the connection position outward is smaller to maintain a higher welding strength; while in the direction of the bus bar extension with smaller stress, the pad 203 area can be significantly reduced to reduce material usage; to balance the connection reliability and manufacturing economy.

[0055] In some embodiments, the area ratio between two adjacent pads 203 along the first direction X is 0.90-0.99; for example, it can be 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98 or 0.99.

[0056] If the ratio is less than 0.90, the pad 203 area decreases too quickly in this direction, and although the pad 203 far from the connection point saves material, the solder joint adjacent to the high stress area may have insufficient area and decreased strength, increasing the risk of disconnection.

[0057] Controlling the area ratio to be 0.90-0.99 means that the area is reduced by only 1%-10% per pad 203 pitch away from the connection position, forming a smooth transition, effectively strengthening the high stress area and avoiding local stress mutation.

[0058] In some embodiments, the area ratio between two adjacent pads 203 in the second direction Y is 0.80-0.95; for example, it can be 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, or 0.95.

[0059] In the second direction Y, the pad 203 area can be reduced more significantly without significantly affecting the connection reliability. The ratio as low as 0.80, i.e., the area is reduced by 20%, can still ensure sufficient solder strength, while significantly reducing the amount of silver paste.

[0060] The steeper area reduction gradient helps to quickly reduce the size of the pad 203 in the low stress area, reducing the consumption of conductive paste and improving economy.

[0061] Reference Figure 6 In some embodiments, the cell body 202 includes a second area 208, which is the area of the cell body 202 other than the first area 204; in the second area 208, the area of the pad 203 close to the first area 204 is greater than that of the pad 203 away from the first area 204 in the first direction X, and the area of the pad 203 close to the first area 204 is greater than that of the pad 203 away from the first area 204 in the second direction Y.

[0062] It can be understood that although the second area 208 is subjected to less stress than the first area 204, the edge area adjacent to the first area 204 is still affected by a certain degree of stress transmission.

[0063] By setting the pad 203 area gradient in the second area 208 to decrease from inside to outside, the moderately high stress area can be moderately strengthened without significantly increasing the material cost, further improving the structural robustness of the solder interface of the entire solar cell 201. At the same time, the pad 203 area away from the first area 204 is moderately reduced, which helps to reduce the consumption of conductive materials such as silver paste and optimize the manufacturing cost.

[0064] Reference Figure 6In some embodiments, the area ratio between two adjacent pads 203 in the first region 204 is greater than the area ratio between two adjacent pads 203 in the second region 208 along the first direction X, and the area ratio between two adjacent pads 203 in the first region 204 is greater than the area ratio between two adjacent pads 203 in the second region 208 along the second direction Y.

[0065] In the first region 204 where the stress concentration is more significant, the pad 203 area decreases at a smaller gradient from the connection position outward, so as to maintain a higher local solder strength; while in the second region 208 where the stress is weaker, the pad 203 area is allowed to decrease at a larger gradient, so as to save material.

[0066] Such a zoned differentiated gradient layout makes the pad 203 size distribution match the actual mechanical load distribution, providing sufficient reinforcement in high stress areas while controlling costs in low stress areas, balancing the connection reliability of the assembly and the manufacturing economy.

[0067] In some embodiments, the area ratio between two adjacent pads 203 in the first region 204 is 0.90-0.99 along the first direction X, for example, it can be 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98 or 0.99; and the area ratio between two adjacent pads 203 in the second region 208 is 0.80-0.95, for example, it can be 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94 or 0.95.

[0068] Along the first direction X, the pad area gradient in the first region 204 changes relatively gently to maintain the solder strength in high stress areas, ensuring that the critical solder joints have sufficient mechanical anchoring force and electrical contact area to resist the stress caused by the stretching or thermal deformation of the electrical connector.

[0069] Along the first direction X, the pad area gradient in the second region 208 changes significantly to effectively save conductive materials such as silver paste and reduce manufacturing costs while ensuring basic solder reliability.

[0070] In some embodiments, the ratio of the area between two adjacent pads 203 in the first region 204 along the second direction Y is 0.90-0.99, for example, it can be 0.90, 0.91, 0.92, 0.93, 0.94, 0.95, 0.96, 0.97, 0.98, or 0.99; the ratio of the area between two adjacent pads 203 in the second region 208 along the second direction Y is 0.80-0.95, for example, it can be 0.80, 0.81, 0.82, 0.83, 0.84, 0.85, 0.86, 0.87, 0.88, 0.89, 0.90, 0.91, 0.92, 0.93, 0.94, or 0.95.

[0071] The gradient of the pad area in the first region 204 along the second direction Y is relatively flat, so as to maintain the welding strength of the high stress area and ensure that the critical pads have sufficient mechanical anchoring force and electrical contact area to resist the stress caused by the stretching or thermal deformation of the electrical connector.

[0072] The gradient of the pad area in the second region 208 along the second direction Y is significantly changed, so as to effectively save the conductive material such as silver paste and reduce the manufacturing cost while ensuring the basic welding reliability.

[0073] In some embodiments, the area of the pad 203 is 0.15 mm2-1 mm2; for example, it can be 0.15 mm2, 0.2 mm2, 0.25 mm2, 0.3 mm2, 0.35 mm2, 0.4 mm2, 0.45 mm2, 0.5 mm2, 0.55 mm2, 0.6 mm2, 0.65 mm2, 0.7 mm2, 0.75 mm2, 0.8 mm2, 0.85 mm2, 0.9 mm2, 0.95 mm2, or 1 mm2.

[0074] It is worth noting that in the above pad area decreasing design, if the area of a certain pad 203 calculated by the gradient is less than 0.15 mm2, the area of the pad 203 is limited to 0.15 mm2; at the same time, the area of all pads 203 located on the side of the pad 203 away from the connection position of the first bus bar 21 and the electrical connector 22 is also uniformly set to 0.15 mm2. The setting of the lower limit value aims to ensure that even in the low stress area, the pad 203 still has sufficient area to maintain reliable welding strength and electrical connection performance, avoiding problems such as false welding, poor wetting, or insufficient mechanical strength due to too small area.

[0075] In the first region 204, the area of the pad 203 closest to the connection position of the first bus bar 21 and the electrical connector 22 can be 0.48 mm2-1 mm2.

[0076] Due to the tensile or thermal stress from the electrical connector 22 near the connection position, if the area of the pad 203 is too small, it is easy to cause insufficient welding strength, leading to de-soldering or false soldering. If the area of the nearest pad 203 is increased to more than 0.48 mm2, the solder wetting area and mechanical anchoring force can be significantly increased, effectively resisting external stress transmission. At the same time, setting the upper limit to 1 mm2 can avoid excessive increase of the pad 203 causing silver paste waste or light loss.

[0077] In some embodiments, the ratio of the width of the cell body 202 in the second direction Y to the width in the first direction X is 2-4.

[0078] Specifically, the standard whole-silicon cell is usually approximately square. If it is cut into two pieces along the first direction X, the aspect ratio of the obtained single cell piece is about 1.7:1, which is less than the lower limit value 2 defined in the embodiments. The setting of the aspect ratio range is intended to clearly define that the embodiments of the present disclosure are applicable to multi-cut cell structures, and exclude conventional two-cut cells.

[0079] The solar cell 201 can be a three-cut cell, a four-cut cell, or an eight-cut cell, etc.

[0080] It should be noted that the multi-cut cell described herein can be obtained by cutting a standard whole cell, or can be directly prepared from a silicon wafer that meets the corresponding size specifications.

[0081] The photovoltaic module provided by the present disclosure increases the contact area of the pad and the solder strip by designing the area of at least one pad in the area near the connection position of the cell and the bus bar, i.e., the first area, to be larger than the pad area in other areas, thereby improving the welding strength. This can effectively alleviate the stress transmitted to the bus bar due to the stretching or thermal deformation of the electrical connector, reduce the risk of solder strip de-soldering or false soldering, and ultimately improve the reliability and manufacturing yield of the photovoltaic module. Further, by using a differentiated area reduction strategy in the high-stress area and the low-stress area, a relatively gentle area reduction gradient is maintained in the high-stress area to ensure that the key solder joint has sufficient mechanical anchoring force and electrical contact area to effectively resist external stress. In the low-stress area, a more significant area reduction is allowed, which significantly reduces the use of conductive materials such as silver paste and reduces manufacturing costs while ensuring basic soldering reliability. This zoned optimization design achieves a synergistic improvement in reliability and economy. In addition, by limiting the area range of the pad, the solder wetting area and mechanical anchoring force can be significantly increased to effectively resist external stress transmission, while avoiding excessive increase of the pad causing silver paste waste or light loss.

[0082] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present disclosure, and in actual applications, various changes can be made in form and details without departing from the spirit and scope of the present disclosure. Any person skilled in the art can make various modifications and changes without departing from the spirit and scope of the present disclosure, and therefore the protection scope of the present disclosure should be subject to the scope defined by the claims.

Claims

1. A photovoltaic module, characterized in that, include: Multiple battery strings, each battery string including multiple solar cells arranged along a first direction, each solar cell including a cell body and multiple pads disposed on the cell body; Multiple first busbars extend along a second direction and are located at opposite ends of the battery string and electrically connected to the battery string. At least one electrical connector extends along the first direction and is electrically connected to two opposing first busbars; The battery cell body includes a first region, which is a region on the battery cell body near the connection position between the first busbar and the electrical connector. In the first region, the area of ​​at least one of the solder pads is larger than the area of ​​solder pads located in other regions on the battery cell body other than the first region.

2. The photovoltaic module according to claim 1, characterized in that, The plurality of pads are arranged on the cell body along the first direction and the second direction; Within the first region, along the first direction, the area of ​​the pads closer to the connection position is greater than the area of ​​the pads farther from the connection position, and along the second direction, the area of ​​the pads closer to the connection position is greater than the area of ​​the pads farther from the connection position.

3. The photovoltaic module according to claim 2, characterized in that, Within the first region, along the first direction, the area ratio between two adjacent pads is greater than the area ratio between two adjacent pads along the second direction.

4. The photovoltaic module according to claim 3, characterized in that, Along the first direction, the area ratio between two adjacent pads is 0.90 to 0.

99.

5. The photovoltaic module according to claim 3, characterized in that, Along the second direction, the area ratio between two adjacent pads is 0.80 to 0.

95.

6. The photovoltaic module according to claim 2, characterized in that, The battery cell body includes a second region, which is the other region on the battery cell body besides the first region; Within the second region, along the first direction, the area of ​​the pads closer to the first region is greater than the area of ​​the pads farther from the first region, and along the second direction, the area of ​​the pads closer to the first region is greater than the area of ​​the pads farther from the first region.

7. The photovoltaic module according to claim 6, characterized in that, Along the first direction, the area ratio between two adjacent pads in the first region is greater than the area ratio between two adjacent pads in the second region, and along the second direction, the area ratio between two adjacent pads in the first region is greater than the area ratio between two adjacent pads in the second region.

8. The photovoltaic module according to claim 7, characterized in that, Along the first direction, the area ratio between two adjacent pads in the first region is 0.90 to 0.99, and the area ratio between two adjacent pads in the second region is 0.80 to 0.

95.

9. The photovoltaic module according to claim 7, characterized in that, Along the second direction, the area ratio between two adjacent pads in the first region is 0.90 to 0.99, and the area ratio between two adjacent pads in the second region is 0.80 to 0.

95.

10. The photovoltaic module according to claim 1, characterized in that, The area of ​​the pad is 0.15mm² to 1mm².

11. The photovoltaic module according to claim 1, characterized in that, The ratio of the width of the battery cell body in the second direction to its width in the first direction is 2 to 4.

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