DE3210312C2 - - Google Patents

Description

The invention relates to an electrical current conductor web system for flexible, foldable or rollable sun Largenerators of spacecraft made up of several modular, electric with carrier foil sections connected to one another and mechanically connected by hinges.

The solar generators currently used in satellites, such as those in the Intelsat V series, consist of light, rigid, articulated structural plates as solar cell carriers, which can be opened up to areas of up to 30 m ^{2 in the} orbit. With these structure plates, strands and flat cable strips with twistable flat cable spirals or large-diameter loops are used as connecting links for the current conductor systems and screwed or glued.

The next generation of solar generators is designed as a much larger and much lighter support structure, which preferably only consist of flexible harmonica-like folded film substrates and are spanned by telescopic mechanisms to areas of 100 m ² and more.

Because these new film surfaces with a very short distance of only about 2 mm have to be folded up to To achieve little storage space are the tried and tested so far ten, on the back of the solar generators brought flat conductor cables with plugs because of their Bending resistance moments and much too large required bending radii for this new type of solar generator not useable.

US 36 98 958 is a spacecraft with Known solar generators of the type mentioned, where the solar generators are modular and the individual carrier foil sections like a piano hinges are connected to each other and out thin, flexible substrates with applied Thin-film solar cells exist, but goes from that this publication does not show how the electrical Connections with these foldable solar generators too are designed.

The object of the invention is therefore an electrical Current conductor system of the type mentioned create with which the individual large-scale modular Carrier film sections can be equipped and which is suitable to separate the individual sections other simple and qualified for space flight graceful way to connect. The electric conductor rail system should meet the high requirements in general enough in space travel, such as high thermal Alternating stresses resulting from sun and earth shade, as well as the highest reliability requirements over the entire duration of the mission. In addition, the  electrical connecting elements should be designed so that these remain free of tensile stress at all times. The problem also needs to be solved for exchange and repair of entire solar generator sections more times non-destructive disconnection and reconnection to it possible.

This object is achieved in that the current conductor pave the way

• a) on carrier foil sections which are copper-clad, extremely thin and integrated
• b) to section conductor tracks  of the carrier film sections in the manner of a Piano hinge are formed, wherein each protruding ends of the conductor tracks on welding zones of the meet next carrier film sections and there are welded.

Further refinements of the invention result from the subclaims.

In addition to the low weight, it is particularly advantageous of the electrical conductor system also its major drawback Stability against shock-like mechanical loads conditions at the start and sufficient stiffness and Fatigue resistance to the tension forces at the Unfolding and surface tension. The conductor track system can be in the photoresist etching process are manufactured much cheaper than it is due to previously made individual full wiring using strands or flat cables was possible. In addition, there are no connections the carrier film sections the previously required Isolating plug with high space requirement and the high Additional weight of these constructions. The one for the new ones Significant increase in surface area provided by solar generators improvement by a factor of three or more compared to previous ones Constructions would address the problem of plugs with Platzbe may and weight of the previous strands or flat cables increase exponentially.

An embodiment of the invention is shown with reference to the figures. These show

Fig. 1 is a drawing of the back of a flexible foldable solar generator,

Figure 2a, b., C, d ge Examples of Stromleiterbahnenübergän, (separable and reconnectable)

Fig. 3 shows another embodiment (not separable).

In FIG. 1, the back side is shown of a flexible, foldable solar generator. The solar generator is composed of seven SPAs (Solar Panel Assembly) SPA 1 to SPA 7 . Each of these SPAs - hereinafter referred to as carrier film sections - is alternately provided on the vertical dividing lines (hinge axes 2 ) with a large number of piano band-like thin hinge sleeves 3 (see also FIGS . 2a and b), each of which is folded from a carrier film folded over to the front, flap 4 and a tube 5 inserted into the hinge axis 2 , e.g. B. consisting of aluminum or other materials are formed. The folded-over carrier foil tabs 4 and the tubes 5 are firmly glued to the carrier foil 1 (dotted area in FIGS. 2a and b).

The hinge sleeves 3 are shown in Fig. 2a and b at the one Trägerfoliensek tion in a selected division with intervene to, projecting film flaps 6 disposed while sets of changes in the adjacent support sheet section by one pitch length are arranged. As a result, they can interlock exactly when the carrier film section is assembled and connected by a thin plug-in axis 7 . All carrier foil sections have on the outside the division of the joint sleeves 3 according to FIG. 2a and on the inside the division by a division according to FIG. 2b. All carrier foil sections can thus be assembled in the same way and, if necessary, replacement sections can be inserted.

The starting material for the carrier films 1 is a polyimide film with one-sided, if necessary also double-sided copper cladding. The carrier film sections can be coated over the entire surface or only in the section connection area on the top with very thin glass fiber laminates (not shown) in order to improve the flatness after the etching process, the tear resistance and resilience on the glued joint sleeves 3 and thus overall during the unfolding permissible surface tension forces to be applied, and finally to optimize the insensitivity to all mechanical loads that occur. This thin glass fiber coating on the top does not affect the flexibility and foldability of the film composite at the fold lines 8 of the solar generator ( FIG. 1) between the dividing lines (hinge axes 2 ), even with small folding radii of less than 1 mm.

The back of the solar generator has a formed from the copper cladding in the photoresist etching tes electrical current track system 9 (see Fig. 1). The middle strand is specially designed for signal conductors. Starting from the outer carrier film section SPA 1 , the individual conductor tracks 10 for the electrical current obtained from the solar cells are guided as far as possible inside over the entire length of the solar generator to connector plugs on the satellite. After the feed to the center, the current conductor tracks of the next carrier film section run closely next to those of the outer carrier film section, etc., so that overall there is a fir-tree-like, inward increasing occupation of the rear with etched conductor tracks. All Stromlei tracks 10 begin at positive or negative connection points 11 of the solar cell modules 12th They are all guided over fold lines 8 with fold conductor path transitions 13 (see FIGS. 1 and 3) and over the hinge axes 2 at the section ends with section conductor path transitions 14 (see FIGS. 1 and 2a-d). The individual conductor tracks are formed as double conductors for reasons of redundancy. A double positive and a double negative Stromlei ter is referred to as a pair of conductors 15 . On the very outside on the long sides of the solar generator, spare current conductor pairs 16 are provided for the connection of an exchange section at any section position.

After the production of the electrical conductor track system 9 in the etching process for the purpose of insulation on the back of all support film sections SPA 1-7 a thin polyimide film is pressed on, which only leaves the copper conductor free at those points, which will later be welded to adjacent Current conductor ends must be connected.

The current conductor tracks 10 are connected to the fold conductor track transitions 13 ( FIG. 1) by a central web 17 ( FIG. 3). This widened interconnect transition area at the fold lines 8 is divided into a plurality of conductor junctions 19 again by a plurality of slots 18 which have already been etched out, in order to avoid in the event of a conductor tear at this fold point that this can continue.

The transitions at the articulation axes 2 of the dividing lines (FIGS . 2a-d) are designed as follows:

The double conductor tracks 10 of each pair of conductors 15 open in front of the hinge axes 2 of the carrier foil sections SPA 1-7 in widened end surfaces 20 which approximately take up the width of two hinge sleeves 3 and end in front of the edges of the glued carrier foil tabs 4 .

Adjacent to these pads 20 are a plurality, separated by the etched slots 18 conductor tracks continuations 21 to the end edge of the projecting film tabs 6 out only up to the dash-dotted line 22 amplifies on the front side with the thin glass fiber tissue and also to back to this line with insulating are covered. In these film tabs 6 welding window 23 (dashed and hatched ge drawn) are embossed into the polyimide film in the etching process or by means of laser ablation, so that on the surfaces of this welding window 23 from the carrier film side, the copper conductors are locally exposed bare metal.

On welding zones 24 (hatched areas) of the broadened connecting surfaces 20 , the thickness of the laminated copper is increased from the conductor track thickness to the multiple in the galvanic addition process. In the same way, in the etched welding windows 23 (polyimide film window) of the protruding film tabs 6, the conductor track copper layer is thickened to the required extent. These local copper thickenings have the purpose of creating favorable re, ie less extreme layer thickness ratios for the welds provided there, so that the welding parameters can vary within a wide tolerance range and mis-welds can thus be avoided.

When assembling the carrier film sections SPA 1-7 , these are pushed together with the back lying on the assembly table upwards so that the reciprocal joint sleeves 3 engage and align. All protruding film tabs 6 must overlap over the opposite hinge sleeves 3 on the top (= back side) of the carrier film sections, see also Fig. 2d. After threading the thin thru axles 7 into the bores of the glued-in tubes 5 , the carrier film sections are mechanically connected. Then the overlapping conductor tracks continue to be welded 21 by the etched welding window 23 close to their outer edge with the welding zones 24 thickened in copper by several welding points 25 or short welding lines. Narrow, semicircular inlays made of plastic are placed on the hinge axis 2 between the overlapping, overlapping foil tabs 6 and the joint sleeves 3 underneath. These are flexible and matched in their thickness so that they do not allow the overlapping film tabs 6 to lie flat, but instead form slight expansion shafts 26 over the articulated axis 2 , and as a result the outer edges of the tabs are moved back towards the axis.

This stretching shafts 26 (see Fig. 2c) are so di dimensioned that the film flaps 6 hinge sleeves themselves lying in together quantitative expanded state nor with sufficient play to the inside 3, so that the weld points 25 do not experience tensile stresses schmie gene in the gefal ended position .

In the unfolded position, the Dehnungswel len 26 form again and prevent that the tension forces absorbed by the piano hinge of the surface tension can have a negative effect on the welding points 25 .

The welding is preferably carried out using the laser pulse method, since the use of solar generators provided for almost flush flush surface utilization means that the pressure-sensitive solar cell modules 12 glued under the welding zones 24 must not be damaged by electrode pressure. In versions in which the welding zones 24 of the conductor tracks 10 are not covered with solar cells on the front side, resistance welding with a double electrode supplied from above can also be used. Soldering of the connection points is also possible in principle, but is not preferred in space travel on solar generators.

The illustration in FIG. 2d shows a row of the welding points 25 at the outer end of the overlapping conductor track continuations 21 as a first connection. If it becomes necessary to replace a carrier film section in the already integrated solar generator, the film tabs 6 from the underlying welding zones 24 of the adjacent carrier film section SPA 1-7 can be located next to the first rows of welding points 25 at the dividing line 27 shown in dotted lines by means of a Special scalpels are separated. After the reassembly of the carrier film sections at the exchange point, the weld connection can be made by a new weld point row 28 next to the dividing line 27 in the manner described above.

With this connection method there are therefore several repairs doors and welds possible. After completion of the Weldings and their control are released lying copper surfaces of the welds all by means of thin, self-adhesive film strip made of polyimide (not shown) taped and insulated. These insulating films If necessary, strips can be destroyed again Detach freely to carry out necessary repairs.

In the manner described, all of the electrical current lines 10 are at all carrier foil sections in the Endpha integration se connected so that the welds protected by the expansion shafts 26 and remain at each stage, such as handling, Falttests and packaging, free voltages of Zugspan. The busbars of the top-side solar cell modules 12 are welded in the same way through etched te welding window 23 in the carrier film 1 at the positive or negative connection points 11 directly to the associated conductor 10 .

Claims (7)

1. Electrical current track system for flexible, foldable or rollable solar generators of spacecraft, which consist of several modular, electrically interconnected and mechanically connected by hinges carrier foil sections, characterized in that the current tracks ( 10 )

• a) on the carrier film sections (SPA 1-7 ), which are copper-clad, are formed extremely thin-film integrated and
• b) are formed at the section interconnect transitions ( 14 ) of the carrier film sections (SPA 1-7 ) in the manner of a piano hinge, with projecting ends of the conductor tracks meeting welded areas ( 24 ) of the next carrier film sections (SPA 1-7 ) and welded there are.

2. Current conductor system according to claim 1, characterized in that the carrier film ( 1 ) of the carrier film sections (SPA 1-7 ) at the respective projecting ends of the conductor tracks ( 10 ) has correlating film tabs ( 6 ) in the welding window ( 23 ) are introduced. 3. Current conductor system according to claim 2, characterized in that the projecting film tabs ( 6 ) are designed to form expansion shafts ( 26 ). 4. conductor track system according to claim 1, characterized in that the copper thickness of the conductor tracks ( 10 ) in the welding zones ( 24 ) and the welding windows ( 23 ) is increased to a multiple. 5. conductor track system according to claim 1, characterized in that the conductor tracks ( 10 ) are covered to the outside with a thin polyimide film. 6. A conductor track system according to claim 1, characterized in that the conductor tracks ( 10 ) have longitudinal slots ( 18 ) at the projecting ends. 7. current conductor system according to claim 1, characterized in that on the outer longitudinal sides of the carrier film sections (SPA 1-7 ) replacement current conductor pairs ( 16 ) are integrated.