AT12235U1 - PHOTOVOLTAIC ELEMENT, CONNECTION BOX AND PHOTOVOLTAIC MODULE - Google Patents

Description

Austrian Patent Office AT 12235 U1 2012-01-15

description

PHOTOVOLTAIC ELEMENT CONNECTION BOX FOR IT AND PHOTOVOLTAIC MODULE

The invention relates to a photovoltaic element, comprising at least one strand of electrically serially connected photovoltaic cells, wherein the electrical connection of the photovoltaic cells by means of cell connectors, optionally cell connectors consist of several parallel electrical conductors, and the strand a Strangeingangsverbinder, the is connected to the input of the first photovoltaic cell of the strand, and a strand output connector which is connected to the output of the last photovoltaic cell of the strand, wherein optionally consist of the strand input connector and strand output connector of a plurality of parallel electrical conductors.

The invention further relates to a junction box for a photovoltaic element.

Finally, the invention relates to a photovoltaic module with a photovoltaic element and a junction box.

Fig. 1 shows a schematic diagram of the electrical interconnection of a plurality of photovoltaic cells to a photovoltaic module, which is described as an example 60 photovoltaic cells exhibiting photovoltaic module. The individual photovoltaic cells Z1 - Z60 are in the so-called "string process". soldered serially into strands by connecting adjacent photovoltaic cells with electrically conductive cell connectors ZV. These cell connectors are usually designed as alloyed copper strips, and because of the high currents that can flow across the cell connectors, they can be in the form of multiple (e.g., two) parallel conductors. In this example, in each case 20 photovoltaic cells Z1-Z20, Z21-Z40, Z41-Z60 are connected to form one strand, so that a total of three strands S1, S2, S3 are formed. The strand output connector SA1 of the first strand S1, that is, an electrical conductor connected to the output of the last photovoltaic cell Z20 of this strand S1, is connected to the current input connector SE2 of the second strand S2, which is an electrical conductor connected to the input of the first Photovoltaic cell Z21 of this strand S2 is connected, soldered. Likewise, the strand output connector SA2 of the second string S2 is soldered to the current input connector SE2 of the third string S3. Thus, the three strands S1, S2, S3 are also connected in series. The current input connector SE1 of the first strand S1 is electrically conductively connected to the positive pole (+) of the photovoltaic module. The current output connector SE3 of the third string S3 is electrically connected to the negative terminal (-) of the photovoltaic module.

Since, in a shadowing of individual photovoltaic cells, the affected photovoltaic cell from the power generator to the power consumer, there is a risk of so-called "hot spot" formation in the photovoltaic module. In order to prevent this "hot spot" formation, the current is to be conducted past the shaded solar cell via a bypass path, wherein the bypass path is expediently formed by a bypass diode connected in antiparallel to the shaded photovoltaic cell, which prevents a larger voltage across the photovoltaic cell builds up in the reverse direction. In practice, however, it is not common to switch a bypass diode over each individual photovoltaic cell, but for manufacturing reasons, a bypass diode is usually connected via 18-20 solar cells. In the exemplary circuit of Fig. 1, one bypass diode per string is provided. Accordingly, the bypass diode BP1 is connected via the photovoltaic cells Z1-Z20 of the first strand S1, the bypass diode BP2 via the photovoltaic cells Z21-Z40 of the second strand S2 and the bypass diode BP3 via the photovoltaic cells Z41-Z60 of the third strand S3 ,

It should be noted that the strands S1, S2, S3 can be divided into sub-strands. If, for example, ten photovoltaic cells each occupy the length of the photovoltaic module, the photovoltaic cells are arranged in groups of ten parallel to one another. In this case, the tenth photovoltaic cell Z10 is connected to the eleventh photovoltaic cell Z11 by means of a cell cross connector ZQ, as are the photovoltaic cells Z30 and Z31 and 1/13 Austrian Patent Office AT12 235U1 2012-01-15 Z50 and Z51. This arrangement offers the advantage that the string input connectors SE1, SE2, SE3 and string output connectors SA1, SA2, SA3 of the three strings S1, S2, S3 are located on the same side of the photovoltaic module.

The preparation of an electrically interconnected in the manner described above photovoltaic module PM2 according to the prior art will now be described with reference to Figures 9 and 10, wherein Fig. 10 shows the detail X of FIG. 9 in an enlarged view. First, a cleaned glass sheet 1 is provided. Onto this glass pane 1 is then placed a cut front encapsulating film 2 (usually an EVA film). The photovoltaic cells Z1 - Z60 are connected to each other in strands as described above by means of cell connectors ZV and positioned with the optically active side down on the front encapsulating film 2. Each cell connector ZV consists of two parallel tracks. Subcircuits are cross-connected by means of cell cross connectors ZQ. The cell cross connectors can be covered with a lower EVA foil strip 4 for optical reasons and with a lower insulating strip 5 to prevent short circuits. Next, on the front encapsulant sheet 2, electrically conductive, so-called cross connectors QV1 ', QV2', QV3 ', QV4' are positioned, with the first cross connector QV1 'being soldered to the strand input connector SE1 of the first strand, the second cross connector QV2' being soldered to the first The third cross connector QV3 'is soldered to the second strand side output connector SA2 and the third third strand input connector SE3, and the fourth cross connector QV4' is soldered to the third third strand output connector SA3 becomes. All four cross connectors QVT, QV2 ', QV3', QV4 'are bent to an L-shape, so that a leg of the L-shape represents a connecting line. There are thus four connection lines A1-A4, which must be led outwards to the location of a junction box 11. After soldering the four cross connectors QVT, QV2 ', QV3', QV4 ', they are covered with an upper EVA film strip 14 and an upper insulating strip 13 to prevent short circuits between the cross connectors and the photovoltaic cells. Thereafter, the laminate is finished by placing a back encapsulating sheet 6 and a back cover 7 (also a sheet or glass sheet) threaded through the laminate through four external terminals A1-A4 (note the slit 7A provided in the back cover 7) ) and the whole assembly is laminated while applying pressure and heat. The laminate is then edged by a frame adhesive tape 8 and a frame consisting of frame profiles 10 and angle connectors 9. Next, the junction box 12 is fixed on the outside of the rear wall cover 7 by means of an adhesive tape 11 or a hot melt adhesive, and the four external terminals A1-4 are guided inside the junction box 12. The four external connections A1-A4 comprise the plus pole, the minus pole and the common connections for the bypass diodes, compare FIG. 1. The bypass diodes must be arranged outside the laminate due to the development of heat and the necessary heat dissipation , and are therefore integrated in the junction box 12. The four external connections A1-A4 are now contacted in the box with the bypass diodes and connection lines, resulting in the electrical connection shown in Fig. 1.

This known photovoltaic module PM2 has proven itself in practice, but has serious disadvantages in the manufacturing process. In particular, in industrial manufacturing, the cost of the four cross connectors represents a competitive disadvantage. Further, the necessary bending of the four cross connectors to an L-shape is laborious and prone to failure. The necessary soldering of the cross connector with the strand input and output connectors (usually two conductors per connector) is labor-intensive and prone to errors. And finally, the required insertion of the upper insulating strip and the upper EVA foil strip also constitutes an error-prone operation which causes labor costs.

It is an object of the present invention to overcome or at least reduce the disadvantages of the prior art.

This object is achieved by providing a photovoltaic element with the 2/13 Austrian Patent Office AT 12235 U1 2012-01-15

Characteristics of claim 1, further by providing a junction box according to the invention for connection to the photovoltaic element according to the invention, and finally by providing a photovoltaic module, which combines a photovoltaic element according to the invention with a junction box according to the invention. Advantageous embodiments of the invention will become apparent from the claims, the description and the drawings.

The invention is based on the idea of a photovoltaic element comprising at least one strand of electrically connected photovoltaic cells, wherein the electrical connection of the photovoltaic cells by means of cell connectors, and the strand a Strangeingangsverbinder connected to the input of the first photovoltaic cell of the strand is, and a strand output connector which is connected to the output of the last photovoltaic cell of the strand, has to form so that the strand input connector and strand output connector of all existing strands are led out of the photovoltaic element to the outside. As a result, in contrast to the prior art, the interconnection of the strand input connectors and strand output connectors does not have to take place within the laminate by means of cross connectors, but can take place after the completion of the photovoltaic element outside the photovoltaic element, which reduces the workload.

It may seem paradoxical at first glance that the interconnection of the strand input connectors and strand output connectors, whose number is higher than the number of external connection leads in the prior art, should bring advantages in terms of reduced workload. In fact, the inventor has recognized that soldering operations during the manufacture of the laminate are considerably more cumbersome and prone to errors.

The proposed procedure according to the invention brings in total surprisingly large improvements in terms of reducing labor and costs and reliability of the final product. These advantages are mainly due to the fact that the cost of the cross connector to be incorporated into the laminate is eliminated, the labor costs and the risk of bending the cross connectors into an L-shape are eliminated, strand input connectors and strand output connectors do not need to be soldered with cross connectors during laminate production, and upper insulating strip and the upper EVA film strip can be omitted.

For the assembly of a photovoltaic module based on the photovoltaic element according to the invention, it is advantageous if the Strangeingangsverbinder and strand output connectors are guided at an edge region of the photovoltaic element to the outside, since then a junction box can also be placed on this edge region.

In a further embodiment of the photovoltaic element according to the invention, the strand input connectors and strand output connectors are led to a side edge of the photovoltaic element to the outside, so that the rear wall of the photovoltaic element remains free of connectors.

The invention also includes a junction box for a photovoltaic element. The junction box has a housing having inlets for string input connectors and string output connectors of n (n = 1, 2, 3 ...) strings of electrically serially connected photovoltaic cells. N + 1 electrical cross connectors are provided inside the housing of the junction box, a first cross connector being connectable to the first input strand input connector and a first photovoltaic module connector, the (n + 1) th cross connector to the nth strand strand output connector and a second photovoltaic module connector second photovoltaic module connection is connectable, as well as, if n > 1, in each case the strand output connector of a strand and the strand input connector of the following strand are connectable to a common cross connector. Between cross connector, in particular between the adjacent cross connector, bypass diodes are connected. This means that in the junction box according to the invention, the cross connector and the bypass diodes are integrated, so that only the strand input connector and strand output connector of strands of electrically connected photovoltaic cells must be connected to the junction box and connected to the cross connector. Advantageously, for quick and easy connection of the strand input connector and strand output connector, the cross connectors are provided with solder pads or terminals to which photovoltaic module terminals are also connectable. If the strand input connectors and / or strand output connectors have a plurality of conductors connected in parallel, a soldering area or a terminal can be provided for each conductor.

In one embodiment of the junction box according to the invention, the photovoltaic module connections are guided to the outside of the housing. Advantageously, they are configured as cables led through the housing wall or sockets or plugs mounted in a housing wall. As a result, several photovoltaic modules are quickly, easily and without special expertise connected to one another at a construction site.

In a photovoltaic module according to the invention, which combines a photovoltaic element according to the invention and a junction box according to the invention, the string input connectors and string output connectors led outward from the photovoltaic element are guided into the junction box and connected to the cross connectors.

Advantageously, the junction box is placed at or near a side edge of the photovoltaic element. This avoids mechanical stress on the photovoltaic cells since, when the photovoltaic module is placed on a substrate, e.g. a roof truss, the junction box can not press from behind against photovoltaic cells. In addition, this placement of the junction box provides a much better heat dissipation than the conventional arrangement on the back of the photovoltaic module and avoids heat transfer to the photovoltaic cells.

In a preferred embodiment of the photovoltaic module according to the invention, the junction box extends over more than half, preferably over more than 75%, of the length of a side edge of the photovoltaic element. The junction box also receives the function of a cross member, which contributes to the torsional rigidity of the photovoltaic module.

If the connection lines are located on opposite edge regions of the junction box, photovoltaic modules according to the invention can be arranged side by side and electrically connected in series and with short connecting lines.

A high mechanical strength of the mechanical connection between junction box and photovoltaic element is achieved when the photovoltaic element is surrounded by a frame and the junction box is attached to this frame.

A constructed in accordance with the present invention photovoltaic module also brings optical advantages, since the usually be seen on the front module side cross connector accounts. The invention can be used not only for framed glass films photovoltaic modules, but also, for example, for frameless glass-glass modules.

The invention will now be explained in more detail by means of embodiments with reference to the drawings.

Fig. 1 shows a schematic diagram of the electrical connection of a plurality of photovoltaic cells to a photovoltaic module, said electrical interconnection can be provided both in the invention and in conventional photovoltaic taikmodulen; Fig. 2 shows an exploded view of a photovoltaic module according to the invention, which has a junction box according to the invention and a photovoltaic element according to the invention with according to the circuit diagram of Fig. 1 serially interconnected photovoltaic cells.

FIG. 3 shows a plan view of the interconnected photovoltaic cells of the photovoltaic module of FIG. 2.

Fig. 4 shows a longitudinal section through the finished assembled Pho tovoltaikmodul invention. 4.13

Austrian Patent Office AT 12235 U1 2012-01-15 Fig. 5 shows the back of a photovoltaic element according to the invention after its completion.

[0034] [0035]

FIG. 6 shows a detail Y of FIG. 5.

Fig. 7 shows the back of a photovoltaic element according to the invention after its completion.

Fig. 8 shows a schematic representation of a junction box according to the invention.

Fig. 9 shows the exploded view of a Photovoltaikmo-module according to the prior art described above.

FIG. 10 shows a detail X of FIG. 9.

The production of a photovoltaic module PM1 according to the invention connected according to the circuit diagram of FIG. 1 will now be described with reference to FIG. 2. First, a cleaned glass sheet 1 is provided. Onto this glass pane 1 is then placed a cut front encapsulating film 2 (usually an EVA film). The photovoltaic cells Z1-Z60 are connected to each other in the manner described above by means of cell connectors ZV to strands S1, S2, S3 and positioned with the optically active side down on the front encapsulating 2. Each cell connector ZV consists of two parallel conductors, e.g. Copper strips. Subcircuits are cross-connected by means of cell cross connectors ZQ. The cell cross connectors are covered with a lower EVA foil strip 4 and a lower insulating strip 5. Each strand S1, S2, S3 has a strand input connector SE1, SE2, SE3 and a strand output connector SA1, SA2, SA3, which are led out as connection lines to the location of a junction box 20. In this embodiment, the string input connectors SE1, SE2, SE3 and the string output connectors SA1, SA2, SA3 are each configured as two parallel electrical conductors. Thereafter, the laminate is finished by laying a back encapsulating film 6 and a back cover 7 (also a foil or a glass sheet), the electrical conductors of the strand input connectors SE1, SE2, SE3 and the strand output connectors SA1, SA2, SA3 (a total of twelve in this embodiment) Conductor) through holes 7B in the back cover 7 and the whole assembly is laminated by applying pressure and heat. The laminate is then bordered by a frame adhesive tape 8 and a frame consisting of frame profiles 10 and angle connectors 9, resulting in the inventive photovoltaic element PE1. Furthermore, a junction box 20 described in more detail below can be seen, which is fastened with screws 18 to a frame profile 10.

3 shows a top view of the interconnected photovoltaic cells Z1, Z2,... Z60 of the photovoltaic element PE2 of FIG. 2. It shows the connection of respectively 20 photovoltaic cells by means of cell connectors ZV and cell cross connectors ZQ to three strands S1, S2, S3. Further, it can be seen that the strand input connectors SE1, SE2, SE3 and the strand output connectors SA1, SA2, SA3 are led out. This lead-out of the conductors of the strand input connectors SE1, SE2, SE3 and strand output connectors SA1, SA2, SA3 through holes 7B of the back panel cover 7 is shown in FIG. 5, which shows the rear view of the photovoltaic element PE1, and FIG Fig. 5 shows best to see. It can also be seen in this representation that the strand input connectors SE1, SE2, SE3 and strand output connectors SA1, SA2, SA3 are guided outward at an edge region of the photovoltaic element PE1, namely close to a side edge enclosed by a frame element 10.

Next, the junction box 20 is mechanically fixed to the photovoltaic element PE1, as shown in Figures 4 and 7, for example, with screws 18 to a frame member 10. Then, out of the photovoltaic element PE1 outgoing strand input connector SE1, SE2, SE3 and strand output connectors SA1, SA2, SA3 are guided into the junction box 20 and connected to junction boxes QV1, QV2, QV3, QV4 integrated in the junction box (see also Fig. 8). It can be seen from the drawings that the junction box 20 is placed near a side edge of the photovoltaic element PE1. Man 5/13

Claims (12)

Austrian Patent Office AT12 235U1 2012-01-15 recognizes further that the junction box 20 extends over more than half, namely almost over the entire width of the photovoltaic element PE1. In Fig. 7 it can be seen that the connecting lines 23, 24 are located on opposite edge regions of the junction box 20, which allows a simple electrical connection with adjacent photovoltaic modules. A schematic representation of a junction box 20 according to the invention for the photovoltaic element PE1 can be seen in Fig. 8. The junction box 20 has a housing 21 which has inlets 22 for strand input connectors SE1, SE2, SE3 and strand output connectors SA1, SA2, SA3 of n (n = 1 in this example) strands S1, S2, S3 of electrically serially connected photovoltaic cells. It should be noted that the strand input and output connectors in this example are each designed as double conductors and an inlet 22 is provided for each conductor. However, it is also possible to guide a plurality of conductors of a connector through a common inlet 22, since they are already electrically connected to each other in parallel. In the interior of the housing 22 n + 1 electrical cross-connector, ie four cross-connector QV1, QV2, QV3, QV4, provided, wherein a first cross-connector QV1 by means of solder pads 29 and terminals 27 with the strand input connector SE1 of the first strand S1 and a first Photovoltaikmodul- Terminal 23 is connectable. The second cross connector QV2 is connectable to the strand output connector SA1 of the first strand S1 and the strand input connector SE2 of the second strand S2 by means of solder pads 29. The third cross connector QV3 is connectable to the strand output connector SA2 of the first strand S2 and the strand input connector SE3 of the third strand S2 by means of solder pads 29. The fourth cross connector QV4 is connectable by means of solder pads 29 or terminals 28 to the strand output connector SA3 of the third strand S3 and a second photovoltaic module connection 24. Between the adjacent cross connectors QV1, QV2 and QV2, QV3 and QV3, QV4, a bypass diode BP1, BP2, BP3 is connected in each case. At the cross connectors QV1, QV2, QV3, QV4, a separate solder pad 29 is provided for each conductor of the string input connectors and string output connectors. The outputs 23, 24 are formed as cables, which are led out through outlets 25, 26 from the housing 21 of the junction box 20. Alternatively, the outputs could also be configured as sockets or plugs mounted in a housing wall. Claims 1. Photovoltaic element (PE1), comprising at least one strand (S1, S2, S3) of electrically connected photovoltaic cells (Z1 - Z60), wherein the electrical connection of the photovoltaic cells by means of cell connectors (ZV), optionally cell connectors of several parallel connected consist of electrical conductors, and the at least one strand (S1, S2, S3) a Strangeingangsverbinder (SE1, SE2, SE3) connected to the input of the first photovoltaic cell (Z1, Z21, Z41) of the strand (S1, S2, S3) and a strand output connector (SA1, SA2, SA3) connected to the output of the last photovoltaic cell (Z20, Z40, Z60) of the strand (S1, S2, S3), wherein optionally the strand input connectors (SE1, SE2, SE3) and strand output connectors (SA1, SA2, SA3) consist of a plurality of parallel electrical conductors, characterized in that the strand input connectors (SE1, SE2, SE3) and strand output connectors (SA1, SA2, SA3) are made from d em photovoltaic element (PE1) are guided to the outside. 2. Photovoltaic element according to claim 1, characterized in that the strand input connectors (SE1, SE2, SE3) and strand output connectors (SA1, SA2, SA3) are guided at an edge region of the photovoltaic element (PE1) to the outside. The photovoltaic element according to claim 1, characterized in that the strand input connectors (SE1, SE2, SE3) and strand output connectors (SA1, SA2, SA3) are led out at or near a side edge of the photovoltaic element (PE1). 6/13 Austrian Patent Office AT 12235 U1 2012-01-15 4. junction box (20) for a photovoltaic element (PE1), with a housing (21), characterized in that the housing (21) inlets (22) for strand input connector (SE1, SE2, SE3) and strand output connector (SA1, SA2, SA3 ) of n (n = 1, 2, 3 ...) strands (S1, S2, S3) of electrically serially connected photovoltaic cells (Z1 - Z60), that in the interior of the housing (21) n + 1 electrical cross connectors (QV1 , QV2, QV3, QV4), wherein a first cross connector (QV1) is connectable to the string input connector (SE1) of the first string (S1) and a first photovoltaic module connector (23), the (n + 1) th cross connector (QV4) is connectable to the strand output connector (SA3) of the nth strand (S3) and a second photovoltaic module connection (24), that when n > 1, then each of the strand output connector (SA1, SA2) of a strand (S1, S2) and the strand input connector (SE2, SE3) of the subsequent strand (S2, S3) are connectable to a common cross connector (QV2, QV3), and that between cross connector (QV1, QV2, QV3, QV4), in particular between the adjacent cross connectors (QV1, QV2, QV2, QV3, QV3, QV4), bypass diodes (BP1, BP2, BP3) are connected. 5. Junction box according to claim 4, characterized in that the cross connectors (QV1, QV2, QV3, QV4) solder pads (29) or terminals (27, 28) for connection with Stang input connectors, strand output connectors, or photovoltaic module terminals. 6. Junction box according to claim 5, characterized in that, if the strand input connectors (SE1, SE2, SE3) and / or strand output connectors (SA1, SA2, SA3) comprise a plurality of conductors connected in parallel, for each conductor a soldering surface (29) or terminal ( 27, 28) is provided. 7. Junction box according to one of claims 4 to 6, characterized in that the photovoltaic module connections (23, 24) are guided to the outside of the housing, in particular as passed through the housing wall cable or in a housing wall mounted sockets or plugs are configured. 8. photovoltaic module (PM1) with a photovoltaic element (PE1) according to one of claims 1 to 3 and a junction box (20) according to one of claims 4 to 7, characterized in that the out of the photovoltaic element (PE1) outwardly guided strand connector (SE1 SE2, SE3) and strand output connectors (SA1, SA2, SA3) are inserted into the junction box (20) and connected to the cross connectors (QV1, QV2, QV3, QV4). 9. Photovoltaic module according to claim 8, characterized in that the junction box (20) is placed at or near a side edge of the photovoltaic element (PE1). 10. Photovoltaic module according to claim 8 or 9, characterized in that the junction box (20) over more than half, preferably over more than 75%, the length of a side edge of the photovoltaic element (PE1) extends. 11. Photovoltaic element according to claim 10, characterized in that the connection lines (23, 24) are located on opposite edge regions of the junction box (20). 12. Photovoltaic module according to one of claims 8 to 11, characterized in that the photovoltaic element (PE1) by a frame (10) is surrounded and the junction box (20) is attached to this frame (10). For this 6 sheets drawings 7/13