DE102011004369B4 - Junction box and set of junction boxes and solar cell arrangement - Google Patents

Abstract

Junction box (1, 21) of a solar cell arrangement, wherein the junction box comprises a lower part (3) and a separate, mechanically connected to the lower part upper part (7) and in one (3) of lower part and upper part first contact elements (C1 to C5), of which one part in the assembled state are connected to the solar cells and two of which (C1; C5) are connected to a connecting cable (5a; 5b) of the solar cell arrangement, and in the other (7) of the lower part and upper part interconnected second contact elements (S1 to S5 ), which contact the first contact elements electrically in the mounted state and connect to each other, and at least one electronic functional element (25; 27; 29) are arranged for realizing at least one additional function for at least a portion of the solar cells such that the functional element in the mounted state in the Solar cell array is inserted at least functionally, wherein at least one of the outgoing of the solar cell array Ans drain cable (5a; 5b) is electrically connected to the solar cell arrangement only in the mutually mechanically connected state of lower part (3) and upper part (7).

Description

The invention relates to a junction box of a solar cell arrangement, in particular of a solar module with a plurality of solar cells connected in multiple strings, wherein the junction box comprises a lower part and a separate, mechanically connected to the lower part upper part. It further relates to a set of such solar cells and equipped with such a junction box solar cell array.

State of the art

Crystalline solar modules consist of photovoltaic cells, which are connected in series in so-called strings. A typical solar module consists of 60 series-connected solar cells. These 60 cells are interconnected in three strings of 20 cells each. These strings are bridged antiparallel in today's modules, each with typically a bypass diode. These bypass diodes have the task, when shading one or more cells of a string, to bypass the current generated by the unshaded system at this bottleneck created by the shaded cells. The diodes thereby take over the possible reduced current through the shading and pass it past the shaded cells in order to prevent a limitation of the total current flow and thus of the total solar power to be removed in the (partial) shading case. These bypass diodes are located in the solar module junction box, a plastic housing in which the solar cell connections from the module are connected with flexible, electrical cables, which in turn connect the solar modules with each other.

In the structural design of the junction boxes numerous variants have become known. Typically, they consist of a on the support of the solar cell assembly (especially the solar module) applied lower part in which the conductor elements for electrical connection of the strings and the mentioned bypass diodes are housed, and a lid placed on the lid, which closes the junction box and the therein contained electrical and electronic components.

Current developments now point to the need for a protective shutdown of the solar modules in case of danger, z. B. in a fire. This need exists but only in certain applications z. B. in roof-mounted systems. Solar modules on open space, so z. B. on heap areas, these additional costs do not generate generating variant. Other systems, however, may require additional, module-based electronic components, the z. B. a module monitoring for monitoring or theft protection or a local power adjustment for yield optimization by DC / DC converter.

This raises the problem that application-specific solar modules must be constructed with a respective electronic equipment, which makes the production and logistics consuming, by different systems must be produced and kept in stock. In a more recent design embodiment, the connection unit is separated from the functional unit by the connection unit is designed as a "simple" box, to which a second box, in which the functional unit is located, can be infected. The connection unit is connected so that a drop in the functional unit causes no functional restriction in the normal case. This means that the external connection cables are firmly connected to the "external connections" of the 60 solar cells connected in series, so that if the functional unit drops off, the bypass diodes are missing, but the solar module continues to function properly when unshaded.

Furthermore, the describes DE 10 2008 062 034 A1 a connection device of a solar module, which comprises a connection plate and a connector housing, which are each glued to the solar module.

Furthermore, the describes DE 20 2008 006 111 U1 a junction box with a lid having a contact with contact legs of a bypass diode.

Disclosure of the invention

According to the invention a junction box with the features of claim 1 is provided. Furthermore, a set of connection boxes with the features of claim 9 and a solar cell arrangement with the features of claim 10 are provided.

It proposes a junction box, in which at least one electronic functional unit in the upper part (cover) of the box is integrated. As a result, solar modules can be manufactured as standard with a junction box body in mass production. Only the plugging of the lid defines the additional function of the solar module via the circuit installed in the lid.

The invention thus includes the idea of a modular implementation of different connection or functional concepts in solar cell arrangements, especially in commonly constructed solar modules, by a standard functionality in Junction box bottom part is realized and additional components for the realization of additional functionality in the junction box upper part are housed and their function is realized by the mechanical connection between the upper and lower part. Different populated tops are advantageously interchangeable modules and allow a flexible and easily adaptable to future requirements design of solar cell assemblies.

Basically, this modularity is also possible in a functional interchanging of lower and upper parts, but this does not represent the optimal execution from the current perspective.

According to the invention, the contact elements are further configured such that at least one of the outgoing from the solar cell array connection cable is electrically connected to the solar cell assembly only when correctly mounted upper part (cover). This ensures that no current flows with the top removed, so that when servicing the tops of two adjacent modules are removed, the string can be safely operated.

In one embodiment of the invention it is provided that the first and second contact elements are designed as plug contacts, which come into contact with each other when placing the upper part on the lower part. Preferred dimensions here are the first and / or second contact elements to achieve a positioning tolerance yielding, in particular resilient, formed.

In a further constructive embodiment of the proposed junction box locking means for mechanical locking between the upper part and lower part or between the upper part and a mechanical support of the solar cell assembly are provided, which at the same time hold the first and second contact elements in engagement.

In addition to complete junction boxes, which have the features of the invention, independent lower parts, which have the features claimed in the terminal box base, as well as independent tops, which have the features claimed in the terminal box upper part, to be regarded as embodiments of the invention. In this respect, a ground-interconnected can body with connected solar cell strings and outgoing cable (plus / minus) in the form that at least one cable is not connected to the solar cell strings with not connected counterpart, the solar module is thus switched off, considered to be inventive , Likewise, a solar box lid in a modular form, so that the additional functionality of the solar module is defined by plugging, clipping or insertion of this modular cover, as to be considered according to the invention.

In further expedient embodiments, bypass diodes are provided on the one hand as electronic functional elements, which are electrically connected in the mounted state in the solar cell array. In combination herewith or independently thereof, a design is expedient in which a DC / DC and / or a DC / AC converter and / or a device for protection release is provided as electronic functional elements, which between the solar cell array and the junction box side End of the connection cable is looped. In a further embodiment, a monitoring or control unit of the solar cell arrangement, in particular a control unit for power adjustment and / or a temperature monitoring / operation control unit for temperature-dependent operation control is provided as an electronic functional unit.

As noted above, the subject matter of the present invention is in particular the junction box of a conventionally constructed solar module with string-connected crystalline type solar cells, especially silicon-based. In principle, however, a junction box constructed according to the invention can also serve as a connection unit of other solar cell arrangements, in principle also of a different type in connection with solar cells.

drawings

Incidentally, advantages and expediencies of the invention will become apparent from the following description of exemplary embodiments with reference to the figures. From these show:

1 in a schematic perspective view of the basic structure of a junction box according to an embodiment of the invention and

2 the essential electrical and electronic functional units of a set of junction boxes according to an embodiment of the invention.

1 shows a simplified perspective view of the parts of a junction box 1 a solar cell module, namely a lower part (main body) 3 with connection cables 5a and 5b and a top (lid) 7 , A wrap-around reset frame 9 on the inside of the top 7 has an undercut edge, so that in engagement with correspondingly formed (or inserted) projections 11 at the upper edge of the inner wall of the lower part 3 when placing the upper part on the lower part at the same time a latching closure of the can is effected.

In the lower part 3 is a group of first contact means C1 to C5 to recognize, while in this corresponding positioning, from the inner surface of the upper part 7 projecting vertically, second contact means S1 to S5 are arranged. In the embodiment shown here, the first contact means C1 to C5 have a substantially substantially parallelepiped shape, and the second contact means S1 to S5 are each formed of a support portion (not individually designated) and an omnidirectional contact spring springing therefrom. On the material side, the contact spring is so determined and dimensioned that the second contact elements, even with small manufacturing tolerances in the lower and upper part or the contact arrangements provided therein, securely engage the first contact elements and the electrical contact between the two is maintained over a long period of use with low contact resistance becomes.

In the shell 7 Incidentally, the support surface of the second contact elements S1 to S5 at the same time as a carrier 13 designed for additional electronic functional elements (such as a printed circuit board).

In the 1 shown constructive design is exemplary. It is conceivable z. B. instead of a clipping of the lid and an insertion of the lid in grooves, which are introduced in the solar module body. The connections C1 to C5 of the junction box are included, as in 2 can be seen, interconnected with the solar cells embedded in the solar module and the two connection cables. The connections S1 to S5 of the cover are secured to the support plate mounted in the cover 13 the electronic modules interconnected.

2 shows simplified circuit diagrams and functional circuit diagrams of the electrical / electronic components of a junction box base 21A and three different junction box tops 21B.1 . 21B.2 and 21B.3 sharing a sentence according to the invention 21 of junction boxes to realize a flexible and expandable connection functionality of solar cell assemblies.

While in the only part belonging to the sentence 21A a standard conductor configuration for interconnecting three solar cell strings 23 and the ends of the connection cables 5a . 5b For connection of adjacent modules or for connection to an inverter connected to the first contact elements C1 to C5, the three are included in the set 21 belonging tops 21B.1 to 21B.3 each connecting conductor sections and at least one additional electronic functional element. At the top 21B.1 these are three bypass diodes 25 between the second contact elements S1 / S2, S2 / S3 and S3 / S4 or a shift control unit 27 between the second contact elements S4 and S5. The top 21B.2 contains (with omission of the aforementioned switching control unit) only three bypass diodes 25 , and at the top 21B.3 are neither a switching control unit nor bypass diodes, but only a DC / DC converter 29 intended.

The electrical circuits in 2 are exemplary. Instead of the top 21B.3 illustrated embodiment with DC / DC converter can also be a micro-inverter, so a DC / AC converter, are used. Likewise, the execution of the tops 21B.1 and 21B.2 conceivable with so-called intelligent bypass diodes. In this case, intelligent bypass diodes are switching transistors which switch through with reverse polarity (bypass case) and generate significantly lower power losses due to their inherently low through-resistance.

At the top 21B.2 For example, a Control Unit CU can consist of a simple temperature monitoring circuit or, with a highly complex communication interface via remote control, can switch off the module. Each of the variants can also be combined with a module monitoring, wherein z. B. Module temperature and module voltage can be determined and sent to a central evaluation. The electronics applied in the cover can have an individual serial number which can be interrogated via an integrated or separate communication interface. Likewise, an embedding of an RFID chip is conceivable.

Also with regard to the mechanical design of the junction box parts there are numerous design options, provided that a secure mechanical closure and a long-term reliable and low-resistance electrical contacting of the first and second contact elements are ensured. In addition to plug contacts come in principle also screwed into consideration, but these are not optimal from a current perspective because of the complicated handling. For the mechanical connection of the housing parts in addition to snap or snap connections in principle also screw, but also adhesive and other compounds or combinations of different connection principles into consideration.

Claims (10)

Junction box ( 1 ; 21 ) of a solar cell arrangement, wherein the junction box is a lower part ( 3 ) and one of them separate, with the lower part mechanically connected top ( 7 ) and in one ( 3 ) of lower part and upper part first contact elements (C1 to C5), of which a part in the assembled state with the solar cells and of which two (C1; C5) with a connecting cable ( 5a ; 5b ) of the solar cell array are connected, and in the other ( 7 ) of lower part and upper part interconnected second contact elements (S1 to S5), which electrically contact and connect the first contact elements in the mounted state, and at least one electronic functional element ( 25 ; 27 ; 29 ) are arranged for realizing at least one additional function for at least a part of the solar cells such that the functional element is at least functionally inserted in the assembled state in the solar cell array, wherein at least one of the outgoing from the solar cell array connection cable ( 5a ; 5b ) only in the mutually mechanically connected state of lower part ( 3 ) and upper part ( 7 ) is electrically connected to the solar cell array. Junction box according to claim 1, wherein the first contact elements (C1 to C5) arranged in the lower part (3) and fixed in the mounted on the solar cell assembly state with the solar cells, in particular with the strings of the solar module, and the second (S1 to S5) contact elements in the upper part ( 7 ) are arranged. Junction box according to one of the preceding claims, wherein the first (C1 to C5) and second contact elements (S1 to S5) are designed as plug contacts which, when the upper part is put on ( 7 ) on the lower part ( 3 ) come into engagement with each other. Junction box according to claim 3, wherein the first (C1 to C5) and / or second contact elements (S1 to S5) to achieve a positioning tolerance resilient, in particular resilient, are formed. Junction box according to one of the preceding claims, wherein latching means ( 9 ; 11 ) for mechanical locking between upper part ( 7 ) and lower part ( 3 ) or between the upper part and a mechanical support of the solar cell arrangement, which at the same time hold the first and second contact elements in engagement with one another. Junction box according to one of the preceding claims, wherein as electronic functional elements bypass diodes ( 25 ) are provided, which are looped electrically in the mounted state in the solar cell assembly. Junction box according to one of the preceding claims, wherein as electronic functional elements a DC / DC converter ( 29 ) and / or a DC / AC converter and / or device ( 27 ) is provided for protection release, which is looped between the solar cell assembly and the junction box-side end of the connection cable. Junction box according to one of the preceding claims, wherein as electronic functional unit (CU) a monitoring or control unit (CU) of the solar cell array, in particular a control unit for power adjustment and / or a temperature monitoring / operation control unit for temperature-dependent operation control is provided. Sentence ( 21 ) of junction boxes according to one of the preceding claims, which in addition to at least one type lower part ( 21A ) in each case several to the or a lower part matching types tops ( 21B.1 ; 21B.2 ; 21B.3 ), which require a different configuration of electronic functional units ( 25 ; 27 ; 29 ) exhibit. Solar cell arrangement, in particular solar module, with a junction box according to one of claims 1 to 9.

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