A main grid-free photovoltaic module

Abstract

The present invention relates to a main-grid-free photovoltaic module, comprising a front panel, a front / back conductive wire carrier, a front / back conductive wire arranged on the front / back conductive wire carrier, a photovoltaic cell, and a busbar. The positive and negative poles of adjacent photovoltaic cells in the photovoltaic cell face opposite directions, and the front / back conductive wire carrier covers the positive / back electrodes of all photovoltaic cells; the front / back conductive wires connect the photovoltaic cells in series, and / or electrically connect the first and last photovoltaic cells to the busbar. The structure of the present invention does not require the production of a separate wire-film composite electrode unit or a separate photovoltaic cell string during preparation, simplifies the production process of main-grid-free modules, reduces process steps and equipment investment, saves production electricity, saves materials, reduces costs, improves production efficiency, and maximizes the advantage of no need for precise alignment when connecting main-grid-free modules in series, and is compatible with high-density module technologies such as mosaics.

Description

Technical Field

[0001] The invention relates to the field of semiconductor and photovoltaic product manufacturing, and relates to a photovoltaic module, and in particular to a main grid-free photovoltaic module. Background Art

[0002] In recent years, thanks to the continuous efforts of major photovoltaic companies and research institutions, and the continuous research and development of high-efficiency photovoltaic cells and component technologies, the efficiency of photovoltaic power generation has become higher and higher, the cost has become lower and lower, and the competitiveness of photovoltaics has also been increasing.

[0003] Busbar-free module technology is one of the important high-efficiency module technologies. Compared with the traditional busbar technology, which is to weld the welding ribbon and the photovoltaic cell busbar together to lead the current generated by the cell or interconnect with other cells, the busbar-free module uses a thinner and denser composite metal wire to replace the traditional solar cell busbar, which will not only reduce the shading loss and improve the conductivity, but also reduce the amount of silver paste used in photovoltaic cells. Especially for some photovoltaic cells (such as heterojunction cells) that require the use of expensive low-temperature silver paste, the busbar-free module technology can greatly reduce costs. In addition, there is no need for welding ribbon-busbar alignment, which reduces the loss caused by hidden cracks in the cell and improves product stability.

[0004] The current solution for busbar-free cells is to first make multiple wire-film composite electrode units, each of which connects adjacent cells in series in pairs between photovoltaic cell strings, and needs to process the wire-film composite electrode units at the head and tail of the photovoltaic cell string separately, and then make photovoltaic cell strings through hot pressing and other methods, and then form photovoltaic modules through lamination and other steps. Although the string welding step is eliminated, the two steps of film-wire composite and hot pressing string formation are required as a replacement, and the head and tail cell wire-film composite units need to be specially manufactured, which increases the complexity of the process and also leads to potential bottlenecks in mass production. Summary of the invention

[0005] The purpose of the present invention is to provide a busbar-free photovoltaic module.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A busbar-free photovoltaic module, comprising:

[0008] Photovoltaic cell: includes at least one photovoltaic cell string, each of which includes a plurality of photovoltaic cells arranged side by side, the front and back of the photovoltaic cell form electrodes respectively, there is a gap between two adjacent photovoltaic cells, and the positive and negative electrodes face opposite directions,

[0009] Converging belt,

[0010] The front conductive component includes a front conductive wire carrier and a front conductive wire fixedly arranged on the front conductive wire carrier, wherein the front conductive wire carrier covers the front electrodes of all the photovoltaic cells; the front conductive wire connects the front electrodes of two adjacent photovoltaic cells in the same photovoltaic cell string in series, and / or electrically connects the front electrodes of the first and last photovoltaic cells in the same photovoltaic cell string to the busbar.

[0011] Back conductive assembly: including a back conductive wire carrier, a back conductive wire / conductive layer arranged on the back conductive wire carrier, the back conductive wire carrier covers the back electrodes of all the photovoltaic cells; the back conductive wire / conductive layer connects the back electrodes of two adjacent photovoltaic cells in the same photovoltaic cell string in series, and / or electrically connects the back electrodes of the first and last photovoltaic cells in the same photovoltaic cell string to the busbar;

[0012] Front panel and back panel: at least the front panel is made of glass, and the front panel covers the front conductive component; the back panel covers the back conductive component.

[0013] Further preferably, a transparent conductive film (TCO) is provided on the surface of at least one electrode of the photovoltaic cell, and the material of the transparent conductive film is a composite of one or more of ITO, IWO, ITiO, ICeO and AZO.

[0014] Further preferably, the material of the surface of at least one electrode of the photovoltaic cell is Ag, Cu, Ti, Sn, Ni, Al, Au, or a composite of Ag, Cu, Ti, Sn, Ni, Al, Au and one or more of ITO, IWO, ITiO, ICeO, and AZO.

[0015] Preferably, the photovoltaic cell is a double-sided cell, that is, the positive and negative electrodes of the photovoltaic cell are both grid electrodes, and both can be used as light-receiving surfaces.

[0016] Further preferably, the photovoltaic cell is a heterojunction cell.

[0017] Further preferably, at least the front electrodes of the photovoltaic cells have similar electrical properties, and the power and current differences are less than 10%.

[0018] Further preferably, at least the front electrodes of the photovoltaic cells have the same appearance.

[0019] Preferably, the portions of the front conductive wire and the back conductive wire that are in contact with the front electrode and the back electrode of the photovoltaic cell protrude from the front conductive wire carrier and the back conductive wire carrier.

[0020] Preferably, the front conductive wire carrier and the back conductive wire carrier fix the front conductive wire and the back conductive wire by bonding or wrapping.

[0021] Preferably, the front conductive wires and the back conductive wires are electrically and physically connected to the electrode surface of the photovoltaic cell through low-melting-point metal or alloy coatings, graphite powder, graphite wires, and conductive adhesives coated on their surfaces.

[0022] Preferably, a fixer for preventing the front conductive lines and the back conductive lines from being displaced is provided between the front conductive lines and / or between the back conductive lines, and the fixer is perpendicular to the front conductive lines and the back conductive lines.

[0023] Further preferably, the fixator is a thread made of optically transparent material.

[0024] Preferably, the number of the front conductive wires and the back conductive wires is 8-40.

[0025] Preferably, the front conductive wire carrier is a front fixed film; and the back conductive wire carrier is a back fixed film.

[0026] Further preferably, the front fixing film and the front conductive wire form a front wire-film composite electrode; the back fixing film and the back conductive wire form a back wire-film composite electrode.

[0027] Further preferably, the busbar-free photovoltaic module also includes a front adhesive film and a back adhesive film, the front adhesive film is connected to the front fixing film as a whole; the back adhesive film is connected to the back fixing film as a whole, which not only provides packaging but also plays a role in fixing the front conductive wires and the back conductive wires.

[0028] Further preferably, the thickness of the front fixing film and the back fixing film is 20-100 um.

[0029] Further preferably, the front conductive wire carrier and the back conductive wire carrier are provided with multiple layers, and the material of the layer facing the photovoltaic cell side is a low-fluidity material, and the low-fluidity material refers to materials such as PO, EVA, PVB, PE, PP or PMMA.

[0030] Preferably, the back conductive wire carrier is an adhesive layer, and the back panel, adhesive layer and conductive layer form a composite conductive back panel, which not only provides packaging and bonding effects but also serves as the back electrode of photovoltaic cells between series photovoltaic cell strings.

[0031] When preparing the busbar-free photovoltaic module of the present application, first prepare the front conductive module and the back conductive module; arrange the photovoltaic cells with positive and negative poles facing oppositely in a set area and combine the front conductive wires and the back conductive wires to form a series connection in pairs, and then laminate and form an integrated unit after stacking.

[0032] Due to the application of the above technical solution, the present invention has the following advantages and effects compared with the prior art:

[0033] The structure of the present invention does not require the production of a separate wire-film composite electrode unit or a separate photovoltaic cell string during preparation, which simplifies the production process of busbar-free components, reduces process steps and equipment investment, saves production electricity, saves materials, reduces costs, and improves production efficiency. It maximizes the advantage of not requiring precise alignment when connecting busbar-free components in series, and is compatible with high-density component technologies such as mosaics. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Attached Figure 1 This is a schematic diagram of the structure of the first embodiment;

[0035] Attached Figure 2 It is a structural cross-sectional view of the first embodiment of the present invention;

[0036] Attached Figure 3 This is a structural diagram of the second embodiment;

[0037] Attached Figure 4 This is a structural cross-sectional view of the second embodiment;

[0038] Attached Figure 5 This is a schematic diagram of the structure of the third embodiment;

[0039] Attached Figure 6 This is a structural cross-sectional view of the third embodiment;

[0040] Attached Figure 7 Schematic diagram of the structure of the photovoltaic cell in this embodiment. DETAILED DESCRIPTION

[0041] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0043] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0044] Embodiment 1:

[0045] like Figure 1 , 2 A busbar-free photovoltaic module is shown, comprising a front panel 120, a front adhesive film 130, a front wire-film composite electrode 140, a photovoltaic cell, a busbar 150, a back wire-film composite electrode 160, a back adhesive film 170 and a back panel 180. In this embodiment:

[0046] The photovoltaic cell includes at least one photovoltaic cell string 110, each photovoltaic cell string 110 includes a plurality of photovoltaic cells 111 arranged side by side, the front and back sides of the photovoltaic cell form electrodes respectively, and the positive and negative poles of two adjacent photovoltaic cells 111 face opposite directions, that is, the front electrode of one photovoltaic cell 111 is the positive pole, and the front electrodes of the two adjacent photovoltaic cells 111 are the negative poles. The segmented design allows two adjacent photovoltaic cells 111 in the photovoltaic cell string 110 to be connected in series in pairs but avoid short circuit with other photovoltaic cells 111, such as Figure 7 The photovoltaic cell 111 is a double-sided cell, and the photovoltaic cells 111 with the positive pole facing upward and the negative pole facing upward are designed differently and use opposite front and back junctions so that the two types of cells have similar electrical properties on the upper side. Preferably, the power and current differences are both less than 10%, and the number and graphic design of the grid lines on the upper side are the same.

[0047] The front line-film composite electrode 140 includes a front fixed film 141 and a front conductive wire 142 fixedly arranged on the front fixed film 141. Among them: the front fixed film 141 covers the front electrodes of all photovoltaic cells 111, and the thickness of the front fixed film 141 is 20-100um; the front conductive wire 142 is arranged along the arrangement direction parallel to the photovoltaic cell string 110, and the number of roots is 8-40, which is used to connect the front electrodes of two adjacent photovoltaic cells 111 in the same photovoltaic cell string 110 in series. In this embodiment, as shown in the figure, the front electrodes of the first and last photovoltaic cells 111 in the first, third and fifth photovoltaic cell strings 110 are electrically connected to the busbar 150 according to the design. The front fixed film 141 fixes the front conductive wire 142 at a set position by bonding, wrapping, etc., and the side of the front conductive wire 142 in contact with the photovoltaic cell 111 protrudes from the front fixed film 141. The front fixing film 141 can also provide adhesion to the conductive surface of the photovoltaic cell 111 after lamination. Specifically, the surface of the front conductive line 142 is coated with a low melting point metal coating or an alloy coating. In the subsequent lamination process, the low melting point metal or alloy coating melts to form a reliable electrical contact with the grid line of the photovoltaic cell 111.

[0048] Similarly, the structure of the back-surface wire-film composite electrode 160 is similar to that of the front-surface wire-film composite electrode 140, and the back-surface conductive wire 162 is used to connect in series the back-surface electrodes of two adjacent photovoltaic cells 111 in the same photovoltaic cell string 110. In this embodiment, as shown in the figure, the back-surface electrodes of the first and last photovoltaic cells 111 in the second, fourth and sixth photovoltaic cell strings 110 are electrically connected to the busbar 150 according to the design.

[0049] The front panel 120 and the back panel 180 are both made of glass. The front panel 120 covers the front line film composite electrode 140 ; ​​the back panel 180 covers the back line film composite electrode 160 .

[0050] The back panel 180, the back adhesive film 170 and the back wire-film composite electrode 160 are stacked and laid in sequence, and all the photovoltaic cells 111 in each photovoltaic cell string 110 are placed at the position set by the back wire-film composite electrode 160 in a staggered positive and negative arrangement. A busbar 150 is used to connect multiple photovoltaic cell strings 110 in series and parallel and conduct the current to the photovoltaic module, which is usually connected to a junction box arranged outside the module. Then the front wire-film composite electrode 140, the front adhesive film 130, and the front glass 120 are laid in sequence, and finally laminated to make a main grid-free photovoltaic module.

[0051] Embodiment 2:

[0052] like Figure 3 , 4The busbar-free photovoltaic module shown includes a front panel 220, a front fixing film 231, a front conductive wire 232, a photovoltaic cell, a busbar 250, a back fixing film 271, a back conductive wire 272 and a back panel 280. In this embodiment, the front fixing film 231 and the back fixing film 271 are both adhesive films.

[0053] The photovoltaic cell 211 is a heterojunction cell, the front electrode of which is an ITO transparent conductive layer, and the back electrode is a silver grid line screen-printed on the ITO transparent conductive layer.

[0054] The front fixing film 231 adopts a multi-layer structure, wherein the layer facing the photovoltaic cell side is a low-fluidity material, such as PO, EVA, PVB, PE, PP or PMMA, etc., which provides surface adhesion with the photovoltaic cell 211 and provides support for the front conductive wire 232 to prevent the front conductive wire 232 from being displaced during lamination and other processes. The front conductive wire 232 is compounded on the front fixing film 231, and the part of the front conductive wire 232 in contact with the photovoltaic cell 211 protrudes from the front fixing film 231. The front conductive wire 232 is in the shape of a grid that crosses horizontally and vertically, and the front electrode of the photovoltaic cell 211 is connected to the grid-shaped front conductive wire 232.

[0055] The back conductive wires 272 are compounded on the back fixing film 271, and the part of the back conductive wires 272 in contact with the photovoltaic cell 211 protrudes from the back fixing film 271. The back conductive wires 272 are arranged parallel to the arrangement direction of the photovoltaic cell string 210. A fixer perpendicular to the back conductive wires 272 is also provided between the back conductive wires 272. In this embodiment, the fixer is a transparent silk thread made of PET material, which is connected to the back conductive wires 272 by bonding, so that the displacement of the back conductive wires 272 can be avoided in processes such as lamination. The silver grid lines of the back electrodes of the photovoltaic cell 211 are vertically cross-connected with the back conductive wires 272, each forming a metal grid.

[0056] The front panel 120 is made of glass and is covered with a front fixing film 231 ; the back panel 180 is covered with a back fixing film 271 .

[0057] The back panel 280 and the back fixed film 271 compounded with the back conductive wire 272 are stacked and laid in sequence, and all the photovoltaic cells 211 in each photovoltaic cell string 210 are placed at the set position in an alternating positive and negative arrangement. The multiple photovoltaic cell strings 210 are connected in series and parallel using a busbar 250 to conduct the current out of the photovoltaic module, and then the front fixed film 231 compounded with the front conductive wire 232 and the front panel 220 are laid in sequence, and finally laminated to make a main grid-free photovoltaic module.

[0058] Embodiment three:

[0059] like Figure 5 , 6 A busbar-free photovoltaic module is shown, comprising a front panel 320 , a front adhesive film 330 , a front wire-film composite electrode 340 , a photovoltaic cell, a busbar 150 and a composite conductive back panel 380 .

[0060] This embodiment is basically the same as the first embodiment, except that, in this embodiment, a composite conductive back sheet 380 is used to replace the back line film composite electrode, the back adhesive film and the back panel. The composite conductive back sheet 380 includes a back panel 383, an adhesive layer 381 and a conductive layer 382 arranged in sequence. The composite conductive back sheet 380 not only provides packaging and bonding, but also serves as the back electrode of the photovoltaic cell 311 between the photovoltaic cell strings 310 in series.

[0061] All photovoltaic cells 311 in each photovoltaic cell string 310 are placed in the position set by the composite conductive backplane 380 in an alternating positive and negative arrangement, and a plurality of photovoltaic cell strings 310 are connected in series and parallel using a busbar 350 to conduct current out of the photovoltaic module. The front wire film composite electrode 340, the front adhesive film 330, and the front panel 320 are then laid in sequence, and finally laminated to form a main grid-free photovoltaic module.

[0062] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A busbar-free photovoltaic module, characterized in that: include: Photovoltaic cell: includes at least one photovoltaic cell string, each of which includes a plurality of photovoltaic cells arranged side by side, the front and back of the photovoltaic cell form electrodes respectively, and the positive and negative poles of two adjacent photovoltaic cells face oppositely. Converging belt, The front conductive component includes a front conductive wire carrier and a front conductive wire fixedly arranged on the front conductive wire carrier, wherein the front conductive wire carrier covers the front electrodes of all the photovoltaic cells; the front conductive wire connects the front electrodes of two adjacent photovoltaic cells in the same photovoltaic cell string in series, and / or electrically connects the front electrodes of the photovoltaic cells at the head and the tail in the photovoltaic cell string to the busbar. Back conductive assembly: including a back conductive wire carrier, a back conductive wire / conductive layer arranged on the back conductive wire carrier, the back conductive wire carrier covers the back electrodes of all the photovoltaic cells; the back conductive wire / conductive layer connects the back electrodes of two adjacent photovoltaic cells in the same photovoltaic cell string in series, and / or electrically connects the back electrodes of the first and last photovoltaic cells in the photovoltaic cell string to the busbar; The front conductive wire carrier and the back conductive wire carrier are provided with multiple layers, and the material of the layer facing the photovoltaic cell side is a low-fluidity material; a fixer for preventing the front conductive wire and the back conductive wire from being displaced is provided between the front conductive wires and / or between the back conductive wires, and the fixer is perpendicular to the front conductive wire and the back conductive wire; Front panel and back panel: at least the front panel is made of glass, and the front panel covers the front conductive component; the back panel covers the back conductive component.

2. A busbar-free photovoltaic module according to claim 1, characterized in that: A transparent conductive film (TCO) is disposed on the surface of at least one electrode of the photovoltaic cell, and the material of the transparent conductive film is a composite of one or more of ITO, IWO, ITiO, ICeO, and AZO.

3. The busbar-free photovoltaic module according to claim 1, characterized in that: The material of at least one electrode surface of the photovoltaic cell is Ag, Cu, Ti, Sn, Ni, Al, Au, or a composite of Ag, Cu, Ti, Sn, Ni, Al, Au and one or more of ITO, IWO, ITiO, ICeO, and AZO.

4. The busbar-free photovoltaic module according to claim 1, characterized in that: The photovoltaic cell sheet is a double-sided cell.

5. The busbar-free photovoltaic module according to claim 1, characterized in that: The front conductive wire and the back conductive wire are electrically and physically connected to the electrode surface of the photovoltaic cell through the low-melting-point metal or alloy coating, graphite powder, graphite wire, and conductive glue coated on their surfaces, and the parts of the front conductive wire and the back conductive wire that are in contact with the front electrode and the back electrode of the photovoltaic cell protrude from the front conductive wire carrier and the back conductive wire carrier.

6. The busbar-free photovoltaic module according to claim 1, characterized in that: The front conductive line carrier is a front fixed film; the back conductive line carrier is a back fixed film.

7. A busbar-free photovoltaic module according to claim 6, characterized in that: The front fixed film and the front conductive wire form a front wire-film composite electrode, and the back fixed film and the back conductive wire form a back wire-film composite electrode.

8. The busbar-free photovoltaic module according to claim 7, characterized in that: The busbar-free photovoltaic module further comprises a front adhesive film and a back adhesive film. The front adhesive film is connected to the front fixing film as a whole; the back adhesive film is connected to the back fixing film as a whole.

9. The busbar-free photovoltaic module according to claim 1, characterized in that: The back conductive line carrier is an adhesive layer, and the back panel, the adhesive layer and the conductive layer form a composite conductive back panel.

Images