Back contact photovoltaic cell electrode structure, photovoltaic cell interconnection method and cell assembly

Abstract

The invention provides a back contact photovoltaic cell electrode structure, a photovoltaic cell interconnection method and a cell assembly, the back contact photovoltaic cell electrode structure comprises a first polarity Pad point array, a second polarity Pad point array, a first surface insulation Pad point and a second surface insulation Pad point, the first polarity Pad point array and the second polarity Pad point array are respectively provided with corresponding welding strips along the Pad point extension direction, the welding strip is electrically connected with the Pad point; the first surface insulation Pad point is a surface insulation Pad point at a preset position along the Pad point extension direction of the first polarity Pad point array; and the second surface insulation Pad point is a surface insulation Pad point at a preset position along the Pad point extension direction of the second polarity Pad point array. By arranging the surface insulation Pad points and the welding strips, the invalid occupied space is reduced, the proportion of the effective power generation area in the back contact photovoltaic cell assembly is increased, and then the power generation efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solar cells, and in particular to a back-contact photovoltaic cell electrode structure, a photovoltaic cell interconnection method, and a cell assembly. Background Art

[0002] Photovoltaic cells are thin semiconductor sheets that can convert sunlight into electrical energy, also known as solar cells. The positive and negative electrodes of the back-contact photovoltaic cells are both located on the backlight side, allowing more light to directly shine on the semiconductor material of the cell, thereby being fully absorbed and converted into electrical energy.

[0003] In traditional back-contact photovoltaic cell interconnection processes, while the extended solder ribbon can form an effective electrical connection with the busbar, its size occupies the internal space of the back-contact photovoltaic module. This reduces the effective power generation area within the back-contact photovoltaic module, thereby affecting the module's power generation efficiency and hindering the improvement of the photovoltaic module's overall performance.

[0004] Therefore, there is an urgent need for a back-contact photovoltaic cell electrode structure, a photovoltaic cell interconnection method and a cell assembly to solve the above problems. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention provides a back-contact photovoltaic cell electrode structure, a photovoltaic cell interconnection method and a cell assembly.

[0006] The present invention provides a back-contact photovoltaic cell electrode structure, comprising a first polarity pad point array, a second polarity pad point array, a first surface insulating pad point, and a second surface insulating pad point, wherein: The polarities of the first polarity pad point array and the second polarity pad point array are opposite, and the first polarity pad point array and the second polarity pad point array are each distributed with corresponding solder strips along the extension direction of the pad points, and the solder strips are electrically connected to the pad points; The first surface insulating Pad point is a Pad point that is located at a preset position and surface-insulated along the Pad point extension direction of the first polarity Pad point array; the second surface insulating Pad point is a Pad point that is located at a preset position and surface-insulated along the Pad point extension direction of the second polarity Pad point array.

[0007] According to a back-contact photovoltaic cell electrode structure provided by the present invention, the first surface insulating pad point and the second surface insulating pad point are arranged at the head end or the tail end of the pad point array of their respective corresponding polarities, wherein: When the first surface-insulating pad point is arranged at the head end of the first polarity pad point array, the second surface-insulating pad point is arranged at the tail end of the second polarity pad point array; When the first surface-insulating pad dots are arranged at the tail end of the first polarity pad dot array, the second surface-insulating pad dots are arranged at the head end of the second polarity pad dot array.

[0008] According to a back-contact photovoltaic cell electrode structure provided by the present invention, the first surface insulating pad point and the second surface insulating pad point are further arranged at the middle position of the pad point arrays of their respective corresponding polarities, wherein: When the first surface insulating pad point is set at the nth middle position of the first polarity pad point array counted from the head end, the second surface insulating pad point is set at the nth middle position of the second polarity pad point array counted from the tail end; When the first surface insulating pad dot is set at the mth middle position of the first polarity pad dot array counting from the tail end, the second surface insulating pad dot is set at the mth middle position of the second polarity pad dot array counting from the head end.

[0009] According to a back contact photovoltaic cell electrode structure provided by the present invention, busbars are distributed in the first polarity pad point array and the second polarity pad point array, and the busbars are electrically connected to the welding ribbon; Among them, when the first surface insulation pad point and the second surface insulation pad point are set at the middle position in their respective corresponding polarity pad point arrays, and the bus strap is distributed at the location of the first surface insulation pad point or the second surface insulation pad point, the polarity of the bus strap is determined based on the corresponding polarity at the location.

[0010] The present invention also provides a photovoltaic cell interconnection method, comprising: The head ends and tail ends of adjacent back-contact photovoltaic cells are electrically connected by welding ribbons to form a back-contact photovoltaic cell string, wherein the backlight surface of the back-contact photovoltaic cell comprises the back-contact photovoltaic cell electrode structure according to any one of claims 1 to 4; the positive output port and the negative output port of the back-contact photovoltaic cell string are formed based on the connection between the busbar and the welding ribbon.

[0011] According to a photovoltaic cell interconnection method provided by the present invention, the method further comprises: A plurality of the back-contact photovoltaic cell strings are connected in series to form a back-contact photovoltaic cell series array, wherein adjacent back-contact photovoltaic cell strings are electrically connected via the busbar.

[0012] According to a photovoltaic cell interconnection method provided by the present invention, the method further comprises: The first back-contact photovoltaic cell strings in the two back-contact photovoltaic cell series arrays having mirror-image structures are electrically connected through the busbar to form a back-contact photovoltaic cell series-parallel array.

[0013] The present invention also provides a back-contact photovoltaic cell assembly, comprising the above-mentioned back-contact photovoltaic cell electrode structure.

[0014] According to a back-contact photovoltaic cell assembly provided by the present invention, optical optimization is performed on the back side of the photovoltaic cell in a non-photovoltaic cell area thereof using a photovoltaic module back side optical optimization material, wherein the photovoltaic module back side optical optimization material comprises a white adhesive film, a high-reflectivity backboard, a glazed grid glass and a reflective film tape.

[0015] The back-contact photovoltaic cell electrode structure, photovoltaic cell interconnection method and cell assembly provided by the present invention include first and second polarity Pad point arrays with opposite polarities, and the two arrays have corresponding and electrically connected welding strips along the extension direction of the Pad points; there are also first and second surface insulating Pad points, which are respectively located at preset positions in the extension direction of the Pad points of the first and second polarity Pad point arrays and are surface-insulated. This electrode structure reduces ineffective occupied space by arranging surface insulating Pad points and welding strips, thereby increasing the proportion of effective power generation area inside the back-contact photovoltaic cell assembly and thus improving power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 This is one of the schematic diagrams of the back contact photovoltaic cell electrode structure provided by the present invention; Figure 2 This is a schematic diagram of the connection between the solder strip and the Pad dot array provided by the present invention; Figure 3 This is a second schematic diagram of the back contact photovoltaic cell electrode structure provided by the present invention; Figure 4 This is the third schematic diagram of the back contact photovoltaic cell electrode structure provided by the present invention; Figure 5 This is one of the schematic diagrams of the connection between the busbar and the welding ribbon provided by the present invention; Figure 6This is the second schematic diagram of the connection between the busbar and the welding ribbon provided by the present invention; Figure 7 A schematic diagram of the process of the photovoltaic cell interconnection method provided by the present invention; Figure 8 A schematic diagram of the interconnection of a back-contact photovoltaic cell string provided by the present invention; Figure 9 A schematic diagram of a series array of back-contact photovoltaic cells provided by the present invention; Figure 10 A schematic diagram of a series-parallel array of back-contact photovoltaic cells provided by the present invention; Figure 11 This is a schematic structural diagram of the back-contact photovoltaic cell assembly provided by the present invention. DETAILED DESCRIPTION

[0018] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0019] Due to the limited output voltage and power of a single photovoltaic cell, it cannot be used directly as a power supply device. To meet practical application needs, several individual photovoltaic cells are connected in series or parallel and packaged into photovoltaic modules with practical application value.

[0020] In traditional back-contact photovoltaic modules, the pad points of the positive and negative electrodes are distributed in the same manner in the longitudinal direction and the direction perpendicular to the welding ribbon. Among them, the pad points are distributed on the front or back of the photovoltaic cell and are the core structure that can realize the collection and transmission of photogenerated charges at the positive or negative electrode. The pad points are usually composed of conductive materials, generally metallic silver.

[0021] In the series connection process of photovoltaic cells, welding is usually used to connect two adjacent back-contact photovoltaic cells, that is, the positive electrode of the upper cell is connected to the negative electrode of the lower cell through a welding ribbon, thereby forming a series unit of the back-contact photovoltaic cell. Moreover, this series connection is usually carried out in a straight line. When the series path of the back-contact photovoltaic cell needs to be changed, the welding ribbon connecting the positive or negative electrode pad point will first be led out of the cell by a certain distance, and then the busbar is used between the lead-out welding ribbons (located in the outer area of ​​the back-contact photovoltaic cell) to achieve the series connection of the positive electrode welding ribbon and the negative electrode welding ribbon of the adjacent back-contact photovoltaic cell string. Among them, the welding ribbon is a thin wire or thin strip of conductive material, generally made of metal. By welding with the positive electrode or negative electrode of the adjacent photovoltaic cell, the pad points of the same electrode array of the photovoltaic cell and the positive or negative electrodes of the adjacent photovoltaic cells can be interconnected. The busbar is a strip of conductive material, generally made of metal. One of its main functions is to provide a connection medium for the series connection of the main grid lines of the front electrode of the previous photovoltaic cell and the back electrode of the next photovoltaic cell when the series path of the photovoltaic cell string needs to be changed; the second function is to collect the photogenerated charged particles at the positive and negative electrodes of the photovoltaic cell string respectively, and connect them to the output ports of the junction box with the corresponding polarity.

[0022] In the traditional back-contact photovoltaic cell interconnection process, although the lead-out welding ribbon can be combined with the busbar to form an effective electrical connection, the lead-out size also occupies the internal space of the back-contact photovoltaic module, reducing the proportion of the effective power generation area inside the back-contact photovoltaic module, and thus reducing the power generation efficiency of the module.

[0023] Based on the problems existing in the above-mentioned prior art, the present invention designs a back-contact photovoltaic cell electrode structure, and designs one or more surface insulating pad points in the positive electrode pad point array and the negative electrode pad point array of the back-contact photovoltaic cell respectively, so that this surface insulating pad point has the same function of collecting photogenerated charges as other pad points of the same polarity, and can form effective insulation with the cell surface at the corresponding position. In addition, the surface insulating pad points in the adjacent positive electrode pad point array and the negative electrode pad point array are in the same horizontal line direction, and the horizontal line direction is consistent with the welding direction of the busbar on the back of the back-contact photovoltaic cell. The back-contact photovoltaic cell electrode structure provided by the present invention can realize the effective interconnection of the positive and negative electrodes of adjacent back-contact photovoltaic cell strings, so as to realize the change of the series connection path of the back-contact photovoltaic cells, and can greatly improve the power generation efficiency of the corresponding back-contact photovoltaic module.

[0024] Figure 1 This is one of the schematic diagrams of the back contact photovoltaic cell electrode structure provided by the present invention, such as Figure 1As shown, the present invention provides a back contact photovoltaic cell electrode structure, including a first polarity pad point array 101, a second polarity pad point array 102, a first surface insulating pad point 1011 and a second surface insulating pad point 1021, wherein: The polarities of the first polarity pad point array 101 and the second polarity pad point array 102 are opposite. The first polarity pad point array 101 and the second polarity pad point array 102 are each provided with corresponding solder strips distributed along the extending direction of the pad points, and the solder strips are electrically connected to the pad points. The first surface insulating Pad point 1011 is a Pad point at a preset position and surface-insulated along the Pad point extension direction of the first polarity Pad point array 101; the second surface insulating Pad point 1021 is a Pad point at a preset position and surface-insulated along the Pad point extension direction of the second polarity Pad point array 102.

[0025] In the present invention, the polarity of the first polarity pad array 101 and the second polarity pad array 102 are opposite. For example, if the first polarity pad array 101 is a positive polarity pad array, then the second polarity pad array 102 is a negative polarity pad array, and vice versa. This design of opposite polarity is designed to achieve effective separation and collection of positive and negative charges in the photovoltaic cell.

[0026] The first polarity pad array 101 and the second polarity pad array 102 each have corresponding solder strips distributed along the pad's extension direction, and these solder strips are electrically connected to the pads. The solder strips conduct the charge collected by the pads for subsequent collection and output, and serve as an important channel for charge transfer.

[0027] Figure 2 The schematic diagram of the connection between the solder strip and the Pad dot array provided by the present invention can be referred to Figure 2As shown, the soldering ribbon 103 is a thin wire or thin strip of conductive material that connects the positive or negative pad array of the back contact photovoltaic cell, and is usually made of metal. Metal materials have good electrical conductivity and can effectively conduct the photogenerated charges collected by the pad array. In the present invention, there is no specific requirement for the surface of the soldering ribbon. The soldering ribbon can be a smooth physical surface. This smooth surface is convenient for connection with the pad array and reduces obstacles during the connection process; it can also be designed into an optical structure that is conducive to the use of light. For example, by making a specific texture or reflective surface on the surface of the soldering ribbon, the light irradiated on the soldering ribbon can be reflected back into the battery, improving the utilization rate of light and thereby improving the power generation efficiency of the photovoltaic cell. In addition, the connection method between the soldering ribbon and the pad array in the present invention is not limited to welding and bonding. Among them, welding is to fuse the soldering ribbon and the pad array together through high temperature to form a good electrical connection; bonding is to use an adhesive such as conductive glue to bond the soldering ribbon to the pad. This method is more suitable for some occasions where there are requirements for connection stress or high temperature welding is not suitable. In addition, there may be other connection methods, as long as a stable electrical connection between the soldering ribbon and the electrode Pad point can be achieved.

[0028] The first surface insulating pad point 1011 is located at a preset position along the pad point extension direction of the first polarity pad point array 101. In the present invention, the preset position is predetermined according to the design of the battery and the charge transmission requirements, and may take into account factors such as the charge distribution inside the battery and the layout of the solder strips. Figure 1 As shown, the first surface-insulated pad dot 1011 may be disposed at an end of the first polarity pad dot array 101 .

[0029] The first surface insulating Pad point 1011 has the same function of collecting photogenerated charges of the same polarity as other Pad points in the first polarity Pad point array 101. During the operation of the photovoltaic cell, when light is irradiated on the cell, electron-hole pairs are generated, and the first surface insulating Pad point 1011 can collect photogenerated charges of the same polarity. In the present invention, the first surface insulating Pad point 1011 has surface insulating properties, which enables the first surface insulating Pad point 1011 to be effectively insulated from the welding strip or busbar connecting the Pad point array to avoid charge leakage on unnecessary paths, and can also be designed through the internal charge transfer path to transfer the collected photogenerated charges to the adjacent Pad points in the first polarity Pad point array 101, ensuring that the charges can be smoothly aggregated and conducted.

[0030] The second surface insulating pad point 1021 is located at a preset position along the pad point extension direction of the second polarity pad point array 102. Similarly, the preset position of the second surface insulating pad point 1021 is determined based on the battery design requirements. The second surface insulating pad point 1021 has opposite polarity to the first surface insulating pad point 1011, but has the same function. In the present invention, the second surface insulating pad point 1021 can not only collect photogenerated charges with the same polarity as the second polarity pad point array 102, but also has surface insulation properties, can be insulated from the relevant welding strips or bus strips, and at the same time transfer the collected charges to the adjacent pad points in the second polarity pad point array 102 through the internal charge transfer path. In addition, the number of Pad point arrays and the number of welding strips of the back contact photovoltaic cell electrode of the present invention are not limited. Typical numbers are 16, 18, 20, 24 and 30, etc. The number of positive electrode Pad point arrays and negative electrode Pad point arrays can be the same or different; the Pad point arrays of the two polarities can be a typical alternating arrangement or other forms of arrangement.

[0031] The back-contact photovoltaic cell electrode structure provided by the present invention includes first and second polarity Pad point arrays with opposite polarities, and the two arrays have corresponding and electrically connected welding strips along the extension direction of the Pad points; there are also first and second surface insulating Pad points, which are respectively located at preset positions in the extension direction of the Pad points of the first and second polarity Pad point arrays and are surface-insulated. This electrode structure reduces invalid occupied space by arranging surface insulating Pad points and welding strips, thereby increasing the proportion of effective power generation area inside the back-contact photovoltaic cell module, thereby improving power generation efficiency, optimizing the charge collection and transmission process, and helping to improve the performance of the photovoltaic cell module.

[0032] Based on the above embodiment, the first surface insulating pad point and the second surface insulating pad point are arranged at the head end or the tail end of the pad point array of their respective corresponding polarities, wherein: When the first surface-insulating pad point is arranged at the head end of the first polarity pad point array, the second surface-insulating pad point is arranged at the tail end of the second polarity pad point array; When the first surface-insulating pad dots are arranged at the tail end of the first polarity pad dot array, the second surface-insulating pad dots are arranged at the head end of the second polarity pad dot array.

[0033] In the present invention, the back-contact photovoltaic cell electrode structure comprises an array of first and second polarity pads (of opposite polarity), along with corresponding first and second surface-insulating pads. The surface-insulating pads collect photogenerated charges of the same polarity, while also providing insulation from the soldering ribbon or busbar and transferring the charge through internal pathways. Furthermore, the surface-insulating pads can be located at either the beginning or end of the pad array.

[0034] Figure 3 The second schematic diagram of the back contact photovoltaic cell electrode structure provided by the present invention can be referred to Figure 3 As shown, when the first surface insulating Pad point 1011 is placed at the head end of the first polarity Pad point array 101, in order to achieve reasonable design of the electrode structure and effective connection of charge transfer, the second surface insulating Pad point 1021 is set at the tail end of the second polarity Pad point array 102, so as to take into account the charge collection and transmission between the Pad point arrays of different polarities and the connection relationship with the welding strip and the bus strip, so that the electrical performance of the entire electrode structure is balanced and optimized, ensuring that the photogenerated charges can be efficiently collected and conducted.

[0035] For reference Figure 1 As shown, if the first surface insulating pad point 1011 is set at the end of the first polarity pad point array 101, then the second surface insulating pad point 1021 is set at the beginning of the second polarity pad point array 102. This arrangement is also designed to meet the overall design requirements of the electrode structure, ensuring that the pad point arrays of different polarities cooperate with each other during the charge collection and transmission process, avoiding charge leakage and loss, and improving the power generation efficiency of the photovoltaic cell.

[0036] In the present invention, the two photovoltaic cell configurations with back-contact photovoltaic cell electrode structures in the above embodiments can be obtained by rotating either photovoltaic cell configuration 180 degrees to obtain the other photovoltaic cell configuration, with the difference between the two configurations being the polarity of the starting array in the electrode array. The arrangement of the first surface insulating pad points 1011 and the second surface insulating pad points 1021 in the above embodiments can flexibly adapt to changes in the cell structure under different electrode starting polarities, maintaining the stability and efficiency of the electrode structure.

[0037] On the basis of the above embodiment, the first surface insulating pad point and the second surface insulating pad point are further arranged at the middle position of the pad point arrays of their respective corresponding polarities, wherein: When the first surface insulating pad point is set at the nth middle position of the first polarity pad point array counted from the head end, the second surface insulating pad point is set at the nth middle position of the second polarity pad point array counted from the tail end; When the first surface insulating pad dot is set at the mth middle position of the first polarity pad dot array counting from the tail end, the second surface insulating pad dot is set at the mth middle position of the second polarity pad dot array counting from the head end.

[0038] Figure 4 The third schematic diagram of the back contact photovoltaic cell electrode structure provided by the present invention can be referred to Figure 4 As shown, in the present invention, in addition to being set at the head end or tail end of the Pad point array, the first surface insulating Pad point 1011 and the second surface insulating Pad point 1021 can also be set at the middle position of the Pad point array of their respective corresponding polarities.

[0039] Specifically, when the first surface insulating pad point 1011 is set at the nth middle position (eg, Figure 4 In order to ensure the symmetry of the electrode structure and the coordination of charge transfer, the second surface insulating pad point 1021 needs to be set at the nth middle position of the second polarity pad point array 102 counting from the tail end (such as Figure 4 The second pad point in the vertical distribution direction from bottom to top in the second polarity pad point array 102). In the present invention, n is a positive integer, and the specific value can be determined according to factors such as the design requirements of the battery, the length of the pad point array, and the charge distribution.

[0040] For example, if the first polarity pad array 101 has multiple pads, and the first surface-insulated pad 1011 is placed at the third intermediate pad position (i.e., n=3) starting from the head end, then the second surface-insulated pad 1021 should be placed at the third intermediate pad position (counting from the tail end) in the second polarity pad array 102. This arrangement helps balance charge collection and transfer between pad arrays of different polarities, ensuring stable electrical performance of the entire electrode structure.

[0041] In the present invention, when the first surface insulating pad point 1011 is set at the mth middle position of the first polarity pad point array 101 counting from the tail end, correspondingly, the second surface insulating pad point 1021 is set at the mth middle position of the second polarity pad point array 102 counting from the head end. m is also a positive integer, and its value is based on a similar principle to n, and various parameters of the battery need to be comprehensively considered. For example, starting from the tail end of the first polarity pad point array 101, the first surface insulating pad point 1011 is placed at the second middle pad point position (i.e., m=2), and the second surface insulating pad point 1021 is placed at the second middle pad point position of the second polarity pad point array 102 counting from the head end. This setting method is also to achieve efficient collection and transmission of charges in the electrode structure, as well as good coordination between pad point arrays of different polarities.

[0042] On the basis of the above embodiment, busbars are distributed in the first polarity Pad point array and the second polarity Pad point array, and the busbars are electrically connected to the welding ribbon; Among them, when the first surface insulation pad point and the second surface insulation pad point are set at the middle position in their respective corresponding polarity pad point arrays, and the bus strap is distributed at the location of the first surface insulation pad point or the second surface insulation pad point, the polarity of the bus strap is determined based on the corresponding polarity at the location.

[0043] In the present invention, busbars are distributed within the first polarity pad array and the second polarity pad array. These busbars are electrically connected to the soldering ribbons, including but not limited to welding and bonding, as long as they ensure smooth charge conduction. The busbars are strips of conductive material, typically metal. Their surface can be either smooth or optically structured to facilitate light utilization. Their physical dimensions and distance from adjacent photovoltaic cell edges can be flexibly adjusted based on the design requirements of the photovoltaic module.

[0044] Figure 5 This is one of the schematic diagrams for connecting the busbar and the welding strip provided by the present invention, which can be referred to Figure 5As shown, at the beginning or end of the Pad point array, after the busbar 104 is connected to the welding strip, the collected charges of the same polarity are further aggregated. For example, at the beginning or end of the positive electrode Pad point array, the positive electrode welding strip is connected, and the positive electrode welding strip then transfers the charge to the positive electrode busbar; the negative electrode Pad point array is similar, so that the positive and negative electrodes of different back-contact photovoltaic cells can be electrically interconnected through the busbar to form a complete current path. In the present invention, the surface insulating Pad point has surface insulating properties, which can not only achieve effective insulation with the welding strip or busbar connected to the Pad point array, but also transfer the collected photogenerated charges to the adjacent Pad points in the Pad point array through the internal charge transfer path design.

[0045] Figure 6 This is the second schematic diagram of the connection between the busbar and the welding strip provided by the present invention. In the present invention, when the first surface insulating pad point 1011 and the second surface insulating pad point 1021 are set at the middle position of the respective corresponding polarity pad point arrays, and the busbar 104 is distributed at the position of the first surface insulating pad point 1011 or the second surface insulating pad point 1021, the polarity of the busbar 104 corresponds to the polarity at the position. For example, if the first surface insulating pad point 1011 is set at the middle position of the first polarity pad point array 101 (taking the first polarity pad point array as the positive polarity as an example), and the busbar 104 is distributed at the position of the first surface insulating pad point 1011, then the polarity of the busbar 104 is the busbar of the negative electrode (refer to Figure 6 Similarly, the polarity of the bus strip at the second surface insulation Pad point 1021 is also the same.

[0046] Through the above-mentioned design, the present invention can achieve electrical interconnection between different electrodes of different back-contact photovoltaic cells while avoiding short-circuit connection between different electrodes inside the back-contact photovoltaic cell. Regardless of whether the surface insulating Pad point is set at the head, end or middle position of the Pad point array, the normal operation and efficient power generation of the battery can be guaranteed by reasonably designing the busbar.

[0047] Figure 7 The schematic diagram of the process of the photovoltaic cell interconnection method provided by the present invention is as follows: Figure 7 As shown, the present invention provides a photovoltaic cell interconnection method, comprising: Step 701: Electrically connect the head ends and tail ends of adjacent back-contact photovoltaic cells through welding ribbons to form a back-contact photovoltaic cell string, wherein the backlight surface of the back-contact photovoltaic cell includes the back-contact photovoltaic cell electrode structure described in the above embodiment; the positive output port and the negative output port of the back-contact photovoltaic cell string are formed based on the connection between the busbar and the welding ribbon.

[0048] In the present invention, the process of manufacturing a back-contact photovoltaic cell string requires using a welding ribbon to electrically connect the head end and the tail end of adjacent back-contact photovoltaic cells. Figure 8 The interconnection diagram of the back contact photovoltaic cell string provided by the present invention can be referred to Figure 8 As shown, the positive electrode welding strip at the tail end of the previous back-contact photovoltaic cell 801 is connected to the negative electrode welding strip at the head end of the next back-contact photovoltaic cell 801 through the welding strip, so that the charge can be smoothly conducted between multiple cells.

[0049] In the present invention, the positive and negative terminals P and N of a back-contact photovoltaic cell string are formed by connecting a busbar and a welding ribbon. The output terminal is formed by connecting the busbar to the positive or negative electrode of the first cell in the string, or the positive or negative electrode of the last cell in the string. For example, connecting the busbar to the positive electrode welding ribbon of the first cell forms the positive terminal P of the string; connecting the busbar to the negative electrode welding ribbon of the last cell forms the negative terminal N of the string.

[0050] In the present invention, there is no specific limitation on the spacing Wc between adjacent back-contact photovoltaic cells; the specific value can be set based on the desired design. Furthermore, a string of back-contact photovoltaic cells can also function as a separate photovoltaic power generation unit and, through a specific packaging process, form a photovoltaic module M1. This includes single-glass photovoltaic modules, double-glass photovoltaic modules, and modules using other packaging materials and processes, such as organic polymers.

[0051] Based on the above embodiment, the method further includes: A plurality of the back-contact photovoltaic cell strings are connected in series to form a back-contact photovoltaic cell series array, wherein adjacent back-contact photovoltaic cell strings are electrically connected via the busbar.

[0052] Figure 9 The schematic diagram of the back contact photovoltaic cell series array provided by the present invention can be referred to Figure 9As shown, in the present invention, each back-contact photovoltaic cell string is formed by electrically connecting the head and tail ends of adjacent cells of a plurality of back-contact photovoltaic cells through welding ribbons. Then, a plurality of such back-contact photovoltaic cell strings are connected in series, and the series connection method is to connect the output ports of adjacent cell strings through a busbar. For example, the positive port P of the previous back-contact photovoltaic cell string is connected to the negative port N of the next cell string through a busbar, so that the current can flow through multiple cell strings in sequence, thereby forming a back-contact photovoltaic cell series array. The busbar smoothly transmits the current generated by one cell string to the next cell string, ensuring the continuity and stability of the current in the entire series array. It should be noted that the present invention does not impose specific restrictions on the string spacing Ws between adjacent back-contact photovoltaic cell strings, and the string spacing can be adjusted according to actual photovoltaic module design requirements, installation space and other factors.

[0053] The back-contact photovoltaic cell series array formed by the photovoltaic cell interconnection method of the present invention can be used as a photovoltaic power generation unit alone, and a photovoltaic module M2 is formed through a certain packaging process to convert light energy into electrical energy and play a role in the photovoltaic power generation system.

[0054] Based on the above embodiment, the method further includes: The first back-contact photovoltaic cell strings in the two back-contact photovoltaic cell series arrays having mirror-image structures are electrically connected through the busbar to form a back-contact photovoltaic cell series-parallel array.

[0055] In the present invention, multiple strings of back-contact photovoltaic cells are connected in series using the above-described embodiments. Bus bars are used to connect the positive and negative output ports of adjacent strings, forming a series array of back-contact photovoltaic cells. Within each series array of back-contact photovoltaic cells, the strings are connected sequentially, allowing current to flow through each string sequentially.

[0056] Figure 10 The schematic diagram of the back contact photovoltaic cell series-parallel array provided by the present invention can be referred to Figure 10 As shown, with the straight line where the positive and negative ports N and P are located as the axis, the formed back-contact photovoltaic cell series array is mirrored to obtain another back-contact photovoltaic cell series array with a mirror image structure. The two back-contact photovoltaic cell series arrays are in a mirror-symmetric relationship in space.

[0057] In the present invention, the busbar serves a dual purpose. On the one hand, within each series array, the busbar collects photogenerated charge and connects adjacent back-contact photovoltaic cell strings in series, ensuring smooth current transmission within the series array. On the other hand, the busbar serves as an electrical interconnection component, connecting two mirror-image series arrays of back-contact photovoltaic cells. Specifically, the busbar is used to electrically connect the first back-contact photovoltaic cell strings in the two mirror-image series arrays, placing the two series arrays of back-contact photovoltaic cells in electrical parallel.

[0058] Through the aforementioned busbar connection, the present invention forms a series-parallel array of back-contact photovoltaic cells, connecting two mirror-image arrays of back-contact photovoltaic cells in series. This increases the output current of the entire array, and thus the power generation. It should be noted that the spacing Wh between the mirror-image arrays of back-contact photovoltaic cells in series is not specifically limited in the present invention and can be set to a specific value based on the desired design, providing flexibility in array layout.

[0059] The back-contact photovoltaic cell series-parallel array formed by the photovoltaic cell interconnection method of the present invention can be used as a photovoltaic power generation unit alone, and a photovoltaic module M3 can be formed through a certain packaging process for use in a photovoltaic power generation system to achieve efficient conversion of light energy to electrical energy.

[0060] Figure 11 The schematic diagram of the structure of the back contact photovoltaic cell assembly provided by the present invention is as follows: Figure 11 As shown, the present invention provides a back-contact photovoltaic cell assembly, including the back-contact photovoltaic cell electrode structure 1101 described in the above embodiment.

[0061] In the present invention, surface-insulated pads are designed within the back-contacted positive and negative electrode pad arrays of a back-contacted photovoltaic cell. These surface-insulated pads have a dual function: on the one hand, like other pads in the same electrode pad array, they can collect photogenerated charges of the same polarity; on the other hand, they possess surface insulation properties, effectively insulating the soldering ribbons connecting the pad arrays to prevent charge leakage and short circuits, while also transferring the collected charges to adjacent pads in the pad array via internal charge transfer pathways. In back-contacted photovoltaic cell modules, this design ensures efficient and stable charge collection and transfer.

[0062] In the present invention, the designed back-contact photovoltaic cell electrode structure 1101 allows the busbar to be effectively electrically interconnected with the welding ribbon connected to the positive or negative electrode pad points, respectively, in a direction perpendicular to the positive or negative electrode pad point array. In a back-contact photovoltaic cell module, the welding ribbon is used to connect the head and tail ends between adjacent back-contact photovoltaic cells to collect the photogenerated charges generated by the cells; the busbar plays the role of aggregating the charges collected by the welding ribbon, and can realize series or parallel connection between different cell strings. This electrical interconnection method helps to improve the power generation efficiency of the module, while reducing the proportion of ineffective power generation area at the interconnection end (i.e., the area of ​​non-photovoltaic cells formed by the busbar and welding ribbon). In addition, the use of the welding ribbon on the back of the cell for electrical connection of the busbar reduces the amount of raw materials used for the welding ribbon to a certain extent, thereby reducing the production cost of the back-contact photovoltaic module; at the same time, by optimizing the electrode structure and interconnection method, the effective power generation area of ​​the module is increased, thereby improving the power generation efficiency of the photovoltaic module.

[0063] In the present invention, the back-contact photovoltaic cell electrode design and interconnection method are applicable to different numbers of electrode arrays, so that the back-contact photovoltaic cell module can flexibly adjust the number of electrode arrays according to actual needs to adapt to different power generation scales and application scenarios, such as cross-back contact cell technology (IBC), heterojunction back-contact cell technology (HBC), tunnel oxide layer back-contact cell (TBC) and back-contact cell technologies with different cross-techniques (such as HPBC, HTBC, etc.).

[0064] The back-contact photovoltaic cell assembly of the present invention is applicable to single-glass photovoltaic modules, double-glass photovoltaic modules and modules using other packaging materials and packaging processes such as organic polymers, thereby further enhancing the flexibility and adaptability of the assembly.

[0065] Based on the above embodiment, the non-photovoltaic cell area of ​​the back-contact photovoltaic cell is optically optimized using photovoltaic module back optical optimization materials, wherein the photovoltaic module back optical optimization materials include white adhesive film, high-reflectivity backboard, glazed grid glass and reflective film tape.

[0066] In the present invention, by applying these photovoltaic module back optical optimization materials to the non-photovoltaic cell area of ​​the back contact photovoltaic cell, the light irradiating the module can be utilized to the greatest extent, the waste of light energy can be reduced, and the overall power generation efficiency of the photovoltaic module can be improved.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A back contact photovoltaic cell electrode structure, characterized in that: It includes a first polarity pad point array, a second polarity pad point array, a first surface insulating pad point and a second surface insulating pad point, wherein: The polarities of the first polarity pad point array and the second polarity pad point array are opposite, and the first polarity pad point array and the second polarity pad point array are each distributed with corresponding solder strips along the extension direction of the pad points, and the solder strips are electrically connected to the pad points; The first surface insulating Pad point is a Pad point that is located at a preset position and surface-insulated along the Pad point extension direction of the first polarity Pad point array; the second surface insulating Pad point is a Pad point that is located at a preset position and surface-insulated along the Pad point extension direction of the second polarity Pad point array.

2. The back contact photovoltaic cell electrode structure according to claim 1, characterized in that: The first surface-insulated pad point and the second surface-insulated pad point are arranged at the head end or the tail end of the pad point array of their respective corresponding polarities, wherein: When the first surface-insulating pad point is arranged at the head end of the first polarity pad point array, the second surface-insulating pad point is arranged at the tail end of the second polarity pad point array; When the first surface-insulating pad dots are arranged at the tail end of the first polarity pad dot array, the second surface-insulating pad dots are arranged at the head end of the second polarity pad dot array.

3. The back contact photovoltaic cell electrode structure according to claim 1, characterized in that: The first surface-insulating pad point and the second surface-insulating pad point are further arranged at middle positions in the respective corresponding polarity pad point arrays, wherein: When the first surface insulating pad point is set at the nth middle position of the first polarity pad point array counted from the head end, the second surface insulating pad point is set at the nth middle position of the second polarity pad point array counted from the tail end; When the first surface insulating pad dot is set at the mth middle position of the first polarity pad dot array counting from the tail end, the second surface insulating pad dot is set at the mth middle position of the second polarity pad dot array counting from the head end.

4. The back contact photovoltaic cell electrode structure according to claim 3, characterized in that: A busbar is distributed in the first polarity pad point array and the second polarity pad point array, and the busbar is electrically connected to the welding ribbon; Among them, when the first surface insulation pad point and the second surface insulation pad point are set at the middle position in their respective corresponding polarity pad point arrays, and the bus strap is distributed at the location of the first surface insulation pad point or the second surface insulation pad point, the polarity of the bus strap is determined based on the corresponding polarity at the location.

5. A photovoltaic cell interconnection method, characterized in that: include: The head ends and tail ends of adjacent back-contact photovoltaic cells are electrically connected by welding ribbons to form a back-contact photovoltaic cell string, wherein the backlight surface of the back-contact photovoltaic cell comprises the back-contact photovoltaic cell electrode structure according to any one of claims 1 to 4; the positive output port and the negative output port of the back-contact photovoltaic cell string are formed based on the connection between the busbar and the welding ribbon.

6. The photovoltaic cell interconnection method according to claim 5, characterized in that: The method further comprises: A plurality of the back-contact photovoltaic cell strings are connected in series to form a back-contact photovoltaic cell series array, wherein adjacent back-contact photovoltaic cell strings are electrically connected via the busbar.

7. The photovoltaic cell interconnection method according to claim 6, characterized in that: The method further comprises: The first back-contact photovoltaic cell strings in the two back-contact photovoltaic cell series arrays having mirror-image structures are electrically connected through the busbar to form a back-contact photovoltaic cell series-parallel array.

8. A back contact photovoltaic cell assembly, characterized in that: The back contact photovoltaic cell electrode structure comprises the back contact photovoltaic cell electrode structure according to any one of claims 1 to 4.

9. The back contact photovoltaic cell assembly according to claim 8, characterized in that: The non-photovoltaic cell area of ​​the back-contact photovoltaic cell is optically optimized using photovoltaic module back optical optimization materials, wherein the photovoltaic module back optical optimization materials include white adhesive film, high reflectivity backboard, glazed grid glass and reflective film tape.

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