WO2011144546A1 - Electrical connection device intended for electrically connecting a photovoltaic panel - Google Patents

Abstract

Electrical connection device (3) intended for electrically connecting a photovoltaic panel (2), especially intended to connect two photovoltaic panels (2) together, characterized in that it comprises electrical conductors (10) the cross sections of which have aspect ratios higher than 50, in particular higher than 200.

Description

 Electrical connection device for electrically connecting a photovoltaic panel.

The present invention relates to a device for electrical connection of photovoltaic panels. The invention also relates to a photovoltaic panel connection system comprising such an electrical connection device. The invention also relates to a photovoltaic panel comprising such an electrical connection device. The invention also relates to a building cover assembly comprising such a photovoltaic panel or such a connection system. The invention finally relates to a method of producing such a cover assembly.

It is of course known to install photovoltaic panels on roofs of buildings. However, the installation of photovoltaic panels in these places poses many problems. Indeed, we now know photovoltaic panels including connection boxes on their rear face. An exemplary housing is described in EP1102354. These housings are large: typically 50 mm x 80 mm for the smallest. Their thickness is in particular 12 mm for the finest and can even be greater than 20 mm for standard housings. These housings are designed to be mounted on the rear face of the photovoltaic panels on which they are glued. The connection to the rows of photovoltaic cells is through an opening in the bottom of these housings. Conductive bars (busbars) connecting the photovoltaic cells together are connected to an elastic connection internal to the housing. Cables crimped on this internal connectivity ensure the connection to the rest of the installation. These connection boxes also include bypass diodes (or antiparallel since they are mounted antiparallel to the terminals of the rows of cells, generally every 18 cells) to ensure the protection of the cells vis-à-vis the shading. These bypass diodes are for example Schottky diodes, encapsulated in the housings and are generally removable to be changed in case of failure.

SUBSTITUTE SHEET (RULE 26) These known housings glued to the rear face of building cover elements such as steel tanks made of sheet metal, pose unacceptable problems. Indeed, the connection to the photovoltaic panels stuck on the other side of the steel tray requires a cutting of the sheet for the passage of electrical connections. Such a cut presents two problems:

 - It causes a rupture of the watertightness which requires an additional sealing device. A new approval of the cover element is then necessary because it ensures the dual function of supporting the photovoltaic panels and waterproofing of the roof.

 - the modification of the basic product by piercing it poses a problem of trust for the profession of roofers and architects. The protuberance formed by the case glued to the rear face also poses a mechanical problem. On delivery, the cover elements are arranged in packets in which they are superimposed on each other. Each complete package is mounted on the roof by lifting gear. Roofers then slide these roofing elements over the roof to position them. Housings positioned on the underside make these operations delicate because they may be torn off during handling. Furthermore, when the entire roof is mounted, the housings placed on the rear face are no longer accessible. It is therefore necessary for the electrician and the roofer to intervene simultaneously, which poses significant problems of organization of the building sites and wasted time for the electrician. Furthermore, when the photovoltaic panels attached to the cover elements are handled, if they are exposed to solar radiation, voltages of several hundred volts may be present at their connection son. This is restrictive and dangerous.

Thus, the standard boxes are not suitable for these applications. The object of the invention is to provide an electrical connection device for remedying the problems mentioned above and improving the electrical connection devices known from the prior art. In particular, the invention provides an electrical connection device for producing a connection system, a photovoltaic panel and a cover element that are suitable for an application of photovoltaic panels arranged on the roof of a building. The invention makes it possible in particular to facilitate the installation of photovoltaic panels on the roof, to make reliable the waterproofing function of the roof while maintaining a great flexibility of arrangement of the photovoltaic panels with each other.

The electrical connection device according to the invention is intended to electrically connect a photovoltaic panel, in particular to connect two photovoltaic panels together. The connection device comprises electrical conductors whose straight sections have a ratio of dimensions greater than 5, preferably greater than 50, in particular greater than 200. The electrical conductors may be joined into a sheet, preferably a flexible sheet.

The connection device may comprise a bypass diode connecting two electrical conductors to each other.

The diode may be of surface mount type or chip type.

The connection device may comprise a jumper electrically connecting two electrical conductors to each other. The connection device may include a holder for receiving an electrical conductive element for connecting an electrical conductor of the connection device to an electrical conductor of another connection device.

According to the invention, the electrical connection system for photovoltaic panels comprises a first connection device, in particular a first connection device defined above, a second connection device, in particular a second connection device defined above and connection means. electrical conductor of the first connecting device to an electrical conductor of the second connecting device.

The electrical connection means may comprise at least one electrically conductive element, in particular a blade or a wire, mounted tight, for example clamped, on supports electrically connected to the electrical conductors, in particular supports welded to the electrical conductors.

The connection system may comprise a housing enclosing the electrical connection means.

The housing may contain at least one bypass diode connecting two electrical conductors to each other and / or at least one bridge electrically connecting two electrical conductors to each other.

The housing may include housings for receiving fixing pins.

The housing may include a frame and a cover. According to the invention, a photovoltaic panel comprises a set of photovoltaic cells and at least one connection device defined above, and preferably two connection devices defined above.

The at least one connection device can be electrically connected to the set of photovoltaic cells under this set.

According to the invention, a cover assembly comprises a roofing element of a building and at least one photovoltaic panel defined above.

The at least one photovoltaic panel can be assembled by gluing on the cover element.

According to the invention, a cover assembly comprises a roofing element of a building, at least two photovoltaic panels, in particular at least two previously-defined photovoltaic panels and a connection system connecting the at least two photovoltaic panels, in particular a photovoltaic panel. connection system defined above, the at least two photovoltaic panels and the connection system being arranged on the same face of the cover element.

The cover member may include pins for fixing a connection system housing.

According to the invention, a method of manufacturing a cover assembly defined above comprises the following steps:

 provide a cover element;

- fixing an electrically insulating film on a surface of the cover element; fix photovoltaic panels connected by connection systems previously defined on the electrically insulating film.

The fixing steps can be performed, at least primarily, by gluing.

The accompanying drawings show, by way of example, an embodiment of a connection device according to the invention. Figures 1 and 2 are diagrams of front and section of a set of photovoltaic panels according to the invention, arranged on a roof.

FIG. 3 represents electrical schematics of arrangements of several photovoltaic panels according to the invention.

FIGS. 4 and 6 are diagrams of photovoltaic panels connected to each other by means of an electrical connection system according to the invention.

Figure 5 is a diagram illustrating the connection of a photovoltaic panel to an electrical connection device according to the invention.

Figure 7 is a diagram illustrating a variant of a connection means, used in a connection system according to the invention. Figure 8 is a diagram of a cross section of an electrical conductor used in the connection device according to the invention.

A cover assembly according to the invention is described hereinafter with reference to FIGS. 1 and 2. The cover assembly comprises a building cover element 1, photovoltaic panels 2 and connection systems 4 connecting the panels. PV. Unlike what is known photovoltaic panels and connection systems are arranged on the same face of the element 1 cover.

Three groups of three photovoltaic panels are arranged on a cover element. The covering element is for example made of a ribbed metallic material, such as steel, flat surfaces being formed between two successive ribs. The cover element could be made of any other material, such as zinc or copper, and have any other shape. In particular, a cover element could have only a flat range between two ribs.

On each of the flat beaches were arranged three photovoltaic panels. A first photovoltaic panel is connected to a second photovoltaic panel by means of a first connection system 4 and the second photovoltaic panel is connected to a third photovoltaic panel by means of a second connection system 4. At the ends of this group of three photovoltaic panels, a connection device 3 is provided for connecting the group of photovoltaic panels to other photovoltaic panels or other electrical elements.

Thus, the connection system is used to connect together the photovoltaic panels of a row (glued on the flat part of the cover element). They also serve to connect such a row to another row of another cover element placed above or below on the roof. The connection system also allows connection to the electronic power converters of the photovoltaic system at the ridge of the roof. For example, there is no lateral connection between the rows, each row is independent. In this way, the connection system makes it possible to interconnect the photovoltaic panels bonded for example to a steel tank intended for especially the roofs of industrial buildings. This housing provides the connection between panels and the connection to the rest of the installation at the ends of the steel tray. Preferably, as shown in FIGS. 4, 6 and 7, the electrical connection system 4 comprises a first connection device 3, a second connection device 3 and a connection means 16, 25, 16 ', 25' of electrical connection. an electrical conductor 10 of the first electrical conductor connecting device 10 of the second connecting device.

Preferably, the electrical connection means comprises at least one electrically conductive element, in particular a blade 25 or a wire 25 ', tightly mounted, for example pinched, on supports 16, 16' in electrical connection with the electrical conductors. Preferably, the supports are welded to the electrical conductors. The connecting means may also comprise a corrugated blade. All these means allow an electrical connection with one or more degrees of freedom of positioning of the supports, and therefore conductors relative to each other. More preferably, the connection system comprises a housing 22 enclosing the connection means or means. The housing may also include at least one bypass diode 7 connecting two electrical conductors to each other and / or at least one bridge 18 electrically connecting two electrical conductors to each other.

The housing may comprise a frame 22 and a cover closing this frame. The housing is extra flat: its thickness is about equal to that of photovoltaic panels encapsulated under glass, typically of the order of 6mm. It is also airtight and can therefore be arranged on the cover elements on the same side as the panels. Its reduced thickness allows to limit the retention of water, leaves, twigs and particles, especially dust on the roof that is equipped.

Preferably, the housing comprises housings 23 intended to receive fixing pins 24. The fixing pins are integral with the covering element, in particular welded thereto, if the covering element is metallic.

The housing thus makes it possible to connect several conductors of two different connection devices to each other. In the different figures, each connection device 3 comprises several conductors 10, in particular four conductors. The connection device generally has a sheet-like shape, in particular a flexible sheet, formed by two insulating layers between which the electrical conductors are arranged. Preferably, the electrical conductors are arranged parallel or substantially parallel to each other. More preferably, the straight sections of the conductors have a space ratio greater than 5, or even greater than 20, or even greater than 50, or even greater than 100, or even greater than 200. By "space ratio" is meant, as shown in FIG. 8, the ratio of the width L of the conductor to the thickness H of the conductor. The section of the conductor is not necessarily rectangular or is not necessarily strictly rectangular.

Such a connection device structure makes it possible to obtain large electric current passage sections while maintaining a very fine thickness. Thus, such a connection device can be connected to a photovoltaic panel on its rear face, that is to say on the face opposite to the face intended to receive solar radiation. In addition, this small thickness allows to allow the connection device to extend under the photovoltaic panel, between the latter and the cover element. Alternatively, such a connecting device having a very small thickness can penetrate in the photovoltaic panel at one of its edges, that is to say between the face intended to receive the solar radiation and the face opposite to the latter. Preferably, at the ends of the connection device, openings are made at the conductors in one or other of the insulating layers covering the conductors, so as to allow the electrical connection including by performing a weld. In FIG. 5, there are thus made, at a first end of the connection device, openings 12 for the welding of electrical conductors 11 and openings 13 for welding conducting bars 14. Similarly, it is realized, at the second end of the connection device, openings 15 for welding supports 16 of the conduction element 25 and / or openings 20, 21 for welding a bypass diode 7 electrically connecting two electrical conductors the same connection device. Preferably, the bypass diode is of the surface mount type and is attached to one of the conductors. This ensures excellent cooling of the diode. Indeed, it exploits the thermal properties of the electrical conductor and its environment. The choice of such a component also limits the thickness of the housing. The thickness of such diodes is in fact less than 4 mm. In order to gain in thickness, it is possible to use chip-type diodes.

Preferably, the connection device is made as follows: a first film of insulating material is provided in which cutouts are produced, a second film of insulating material is provided in which cutouts are optionally also produced, strips of material are provided; conductive and we put in place the different strips of conductive material between the two insulating films previously mentioned. The insulating films used make it possible to insulate for voltages of up to several thousand volts, the current voltages present between the conductors and between drivers and other elements of the system reach several hundred volts.

Subsequently, the connection devices are connected to the photovoltaic panels, especially at the busbars thereof. Finally, the photovoltaic panels equipped with connection devices are connected together by setting up connection boxes between them. To do this, is placed beforehand, under the connection devices and the location of the connection box, an insulating film, especially when the cover elements are conductive. This frame is then placed on this film, possibly in the form of pins made on the cover element, the frame 22. The conductive elements 25, 25 'are also placed on the supports intended to receive them. A lid is then placed on the frame and fixed, for example by gluing. Then a gel is injected into the casing thus formed. This gel is for example a silicone gel to ensure resistance to moisture.

The invention also relates to a photovoltaic panel 2 comprising an assembly 30 of photovoltaic cells 6 and a connection device as described above. Preferably, the connection device is electrically connected to all the photovoltaic cells in this set. Alternatively, the connection device can enter the set of cells at one of its edges. The invention also relates to a cover assembly comprising a cover element 1 of a building and one or more photovoltaic panels described above. Preferably, the photovoltaic panel (s) are bonded together on the cover element. The invention also relates to a cover assembly comprising a cover element 1 of a building, two photovoltaic panels 2 as described above and a connection system 4 connecting the two photovoltaic panels, the two photovoltaic panels and the connection system being arranged on the same face of the element 1 cover.

Two examples of electrical connection of two groups of two photovoltaic panels are shown in FIG. 3. These circuits represent the photovoltaic panels 2 and the photovoltaic cells 6 that compose them as well as the connection systems 4 that allow the connection of the photovoltaic panels to each other. . In these diagrams, the bypass diodes 7 are also shown in the connection systems. The structure of the connection system is compatible with panels having one or two rows of photovoltaic cells.

The invention also relates to a method of manufacturing such a cover assembly. Such a method comprises the following steps:

 - provide a cover element;

 in the case where the cover member is made of electrically conductive material, attaching an electrically insulating film to a surface of the cover member;

 fix photovoltaic panels connected by connection systems such as those mentioned above.

Preferably, these fixing steps are performed, at least mainly, by gluing. The use of thin connection devices to connect the photovoltaic panels to the housing enables the direct connection of the photovoltaic panel conductor bars with a sufficient level of insulation: class II insulation (ie a double isolation) is necessary for the safety of people. This is achieved by the structure of the connecting devices consisting of 3 layers: insulating material - conductive material - insulating material to ensure both conduction electrical current generated by the panels and the electrical insulation compared to the cover elements.

As seen previously:

 - the connection devices and the housings (base or frame and cover) are glued to the cover element with a flexible glue guaranteeing a good hermeticity;

 - The cover is glued to the base with the same type of glue; and

a gel, for example silicone, is injected into the casing to expel the air;

 The problems of condensation in the housing and water infiltration are thus adjusted. The photovoltaic panel cover elements can thus be mounted on the exposed roof face without fear of short circuit or corrosion problems.

The life of the bypass diodes is extended. Indeed, the reliability of such electronic components strongly depends on their operating temperature (on average: lifetime reduced by a factor of 2 every additional 10 ° C). Cooling the diodes improves their service life. Compared to the state of the art, in the standard housings where the diodes are cooled by the surrounding air, the diodes are soldered on the conductors of the connection devices, these being themselves glued to the elements of blanket. The latter (conductors and cover element) thus serve as heat radiators for the diodes and make it possible to cool them efficiently (junction temperature of 1 10 ° C for an ambient temperature of 70 ° C and a current of 10A, against a temperature of 140 ° C). ° C to 150 ° C for a diode mounted as in the prior art). The lifetime of the diodes being greatly improved, it is no longer necessary to be able to change them easily: they can therefore be in a glued housing in which a gel has been injected. Preferably, particularly when the covering elements are metallic, an insulating film is glued under the connection systems, in particular under the housings to provide class II insulation. Thus, the dielectric strength with respect to the cover element is sufficient, particularly at a housing where, via two interrupted connection devices and a quick connection means, the electrical connection of two upstream and downstream panels is made.

The connection means of two connection devices comprises two supports or bases welded to the connection devices and a member such as a nickel-plated copper terminal bar which is plugged in at the time of the electrical connection of the panels together and before bonding the housing cover. and gel injection therein. Thus, the electrical connection of the two connecting devices of the upstream and downstream panels is done at the factory at the housing before bonding the lid and injection. This connection allows a very fast connection, the passage of a high current (typically of the order of 10A) with a low temperature rise, a small footprint in at least one direction and a large tolerance to defects in positioning and alignment of photovoltaic panels to be connected to each other.

The connection devices preferably have a length greater than that strictly necessary. The conductive bars of the photovoltaic panels are welded to the connection devices at the level of cutouts in the insulating material forming the reception areas. These reception areas are represented by the references 12 and 13 of FIG. 5. The assembly is then folded in accordion to adjust the overflow of the connection device with respect to the edge of the photovoltaic panel as a function of the desired space between two successive panels on the cover element. In the end, the different layers of the assembly are in order from the top: photovoltaic panel, busbars, device connection, glue and cover element. Thus, the space between two photovoltaic panels is variable and adjustable and the layout of the panels on the roofing elements is thus facilitated. Advantageously, a small channel is provided between the edge of the upstream panel and the body of the housing to allow rainwater to flow by causing impurities of small size. The water flows on the panel, then into the channel and then empties on the sides of the cover element, especially between the edges of the panels and the ribs of the cover element when it consists of a steel tray. As seen above, the thickness of the housing is approximately that of the photovoltaic panels. In this way, the large impurities are not retained by oversize. The channel mentioned above can cause dust and prevent them from accumulating, which could eventually degrade the performance of the system. To improve the evacuation of dust, the shape of the housing can also be rounded.

As previously seen, pins may be provided on a cover element, for example these pins may be welded to the steel tanks (thus without drilling). These pins are housed in compartments provided for this purpose in the housings, especially in the corners of the housings. Thus, for security reasons, the connection box can serve as a mechanical stop to the upstream panels. The gluing of the housings is insufficient to fulfill this function correctly. This makes it possible to secure, in certain extreme conditions, the fixing of the photovoltaic panels on the roof, these being only glued on the covering elements. This avoids any risk of sliding panels on the roof and any risk that they fall on the ground (with significant danger for people in the vicinity of the building). As seen above, thanks to the invention, the connection boxes are no longer mounted on the rear face of the cover elements. This type of assembly no longer requires the drilling of the sheet and solves the problems mentioned above.

In this text, the term "roofing element" shall be understood to include a roof covering element of a building or a roofing element of a wall of a building, that is, to say as a cladding element.

Claims

claims 1. Device (3) for electrical connection for electrically connecting a photovoltaic panel (2), in particular for connecting two photovoltaic panels (2) to each other, characterized in that it comprises electrical conductors (10) whose straight sections have a dimension ratio greater than 50, in particular greater than 200. 2. Device according to claim 1, characterized in that the electrical conductors are joined into a sheet, preferably a flexible sheet. 3. Device according to one of the preceding claims, characterized in that it comprises a bypass diode (7) connecting two electrical conductors together. 4. Device according to the preceding claim, characterized in that the diode is of surface mount type or chip type. 5. Device according to one of the preceding claims, characterized in that it comprises a bridge (18) electrically connecting two electrical conductors together. 6. Device according to one of the preceding claims, characterized in that it comprises a support (16; 16 ') for receiving an electrical conductive element (25; 25') for connecting an electrical conductor. (10) of the connection device to an electrical conductor of another connection device. 7. System (4) for the electrical connection of photovoltaic panels comprising a first connection device (3), in particular a first connection device according to one of the claims. previous, a second connection device (3), in particular a second connection device according to one of the preceding claims and an electrical connection means (15, 16, 25, 16 ', 25') of an electrical conductor ( 10) of the first connection device to an electrical conductor (10) of the second connection device. 8. Connection system according to the preceding claim, characterized in that the electrical connection means comprises at least one electrically conductive element (25; 25 '), in particular a blade or a wire, mounted tight, for example pinched, on supports (16; 16 ') in electrical connection with the electrical conductors (10), in particular supports welded to the electrical conductors. 9. Connection system according to the preceding claim, characterized in that it comprises a housing (22) enclosing the electrical connection means (25; 25 '). 10. Connection system according to the preceding claim, characterized in that the housing encloses at least one bypass diode (7) connecting two electrical conductors together and / or at least one bridge (18) electrically connecting two electrical conductors between them. 1 1. Connection system according to claim 9 or 10, characterized in that the housing comprises housings (23) for receiving pins (24) fixing. 12. Connection system according to one of claims 9 to 1 1, characterized in that the housing comprises a frame (22) and a cover. 13. Photovoltaic panel (2) comprising a set (30) of photovoltaic cells (6) and at least one connection device (3) according to one Claims 1 to 6, and preferably two connecting devices (3) according to one of Claims 1 to 6. 14. Photovoltaic panel (2) according to the preceding claim, characterized in that the at least one connection device is electrically connected to the assembly (30) of photovoltaic cells in this set. 15. Cover assembly comprising a building cover element (1) and at least one photovoltaic panel (2) according to claim 13 or 14. 16. Cover assembly according to the preceding claim, characterized in that the at least one photovoltaic panel is assembled by gluing on the cover element. Cover assembly comprising a building cover element (1), at least two photovoltaic panels (2), in particular at least two photovoltaic panels according to claim 12 or 13 and a connection system (4) connecting the photovoltaic panels (2). at least two photovoltaic panels, in particular a connection system according to one of claims 7 to 12, the at least two photovoltaic panels and the connection system being arranged on the same face of the element (1) cover. 18. Cover assembly according to the preceding claim, characterized in that the element (1) cover comprises pins for fixing a housing of the connection system. 19. A method of manufacturing a covering assembly according to one of claims 15 to 18, characterized in that it comprises the following steps: provide a cover element; attaching an electrically insulating film to a surface of the cover member;  fixing photovoltaic panels connected by connection systems according to one of claims 7 to 12 on the electrically insulating film. Manufacturing method according to the preceding claim, characterized in that the fixing steps are performed, at least mainly, by gluing.