The present invention relates to an arrangement for mounting and/or demounting of photovoltaic modules. In particular, the present invention relates to simultaneous

replacement of used foil-based photovoltaic modules with new foil-based photovoltaic modules.

BACKGROUND OF THE INVENTION

The most efficient solar cells have been, and still are, crystalline silicon based solar cells. However, one huge disadvantage of such solar cells is that they require large amounts of energy during manufacturing. Moreover several of the materials used in crystalline silicon based solar cells are so rare that it is not possible to manufacture enough solar cells to cover today's world consumption of electricity.

Accordingly, there has been a need for finding an alternative way of converting solar energy into electrical energy than by using the above-mentioned high efficient crystalline silicon based solar cells.

A promising candidate for replacing crystalline silicon based solar cells is the less efficient and cheap foil-based photovoltaic modules/solar cells which may be manufactured with thicknesses being smaller than 500 μιη. However, the foil-based photovoltaic modules tend to wear out faster than traditional crystalline silicon based solar cells, and for that reason foil- based photovoltaic modules are to be replaced more often.

Therefore, there is a need for a new and an effective arrangement (and associated method) which allows for easy and quick mounting and/or demounting of foil-based photovoltaic modules.

Also, there is a need for a new and an effective arrangement (and associated method) which allows for easy and quick replacement of used foil-based photovoltaic modules with new foil- based photovoltaic modules in an essentially simultaneous process. In large scale

photovoltaic installations simultaneous replacement of cheap foil-based photovoltaic modules may in fact replace costly and time consuming cleaning of dusty modules. Thus, it may be seen as an object of embodiments of the present invention to provide an arrangement that facilities demounting and/or mounting of foil-based photovoltaic modules.

DESCRIPTION OF THE INVENTION

The above-mentioned object is complied with by providing, in a first aspect, a photovoltaic arrangement comprising : a support structure defining a mounting surface onto which a photovoltaic module is detachably mounted; the support structure comprising retaining means for detachably retaining the photovoltaic module relative to the mounting surface, the retaining means being movable between a retaining position in which it retains the photovoltaic module relative to the mounting surface and a non-retaining position in which it does not retain the photovoltaic module relative to the retaining surface, and a mounting/demounting unit comprising at least one mounting/demounting apparatus which when the mounting/demounting unit is moved along the mounting surface, causes the photovoltaic module to be mounted to or demounted from the support structure. The photovoltaic module may comprise a carrier foil, and the total thickness of the photovoltaic module may be below 500 μιη. The limited total thickness of the photovoltaic module allows it to be curved and shaped so as to meet specific demands. Curving and shaping of the photovoltaic modules in a transverse direction may be advantageous during mounting of said modules. The total thickness of the photovoltaic module may be below 500 μιη, such as below 250 μιη, such as below 100 μιη.

The support structure may be a rigid structure secured to ground. The mounting surface, which is defined by the support structure, is angled relative to ground. This allows that photovoltaic modules attached thereto may capture maximum solar energy. As stated the support structure may comprise retaining means/elements for detachably retaining the photovoltaic module relative to the mounting surface. The retaining means are advantageous in that they allow for easy mounting, demounting or simultaneous replacement of photovoltaic modules. In order to allow mounting, demounting or replacement of photovoltaic modules the retaining means may be movable between a retaining position in which it retains the photovoltaic module relative to the mounting surface and a non-retaining position in which it does not retain the photovoltaic module relative to the mounting surface. The retaining means may be implemented in various ways. In an exemplifying embodiment a number of spring-loaded retaining means in the form of spring loaded clamps may be provided. The retaining means may be attached to the mounting surfaces at appropriate intervals.

The mounting /demounting unit may be adapted to move the retaining means between the retaining position and the non-retaining position when moved along the mounting surface. In fact the mounting/demounting unit may be adapted to locally move the retaining means between the retaining and the non-retaining position when moved along the mounting surface. By locally is meant that only retaining means around the mounting/demounting unit is activated. Thus, in a first embodiment the mounting/demounting unit is advantageous in that it may locally move the retaining means from the retaining to the non-retaining position, and subsequently insert at least a part of a new photovoltaic module into a space defined between two retaining surfaces, and subsequently move the retaining means from the non- retaining to the retaining position whereby the new photovoltaic module is retained between the two retaining surfaces. During insertion of the new photovoltaic module the carrier foil, and thereby the photovoltaic module itself, may advantageously be curved or bended in a transverse direction to ease insertion into the space defined between two retaining surfaces.

In a second embodiment, the mounting/demounting unit may be adapted to locally move the retaining means from the retaining to the non-retaining position, and subsequently remove at least a part of a used photovoltaic module away from a space defined between two retaining surfaces, and subsequently move the retaining means from the non-retaining to the retaining position.

In a third embodiment, the mounting/demounting unit may comprise a first

mounting/demounting apparatus and a second mounting/demounting apparatus so that essentially simultaneous replacement of used photovoltaic modules with new photovoltaic modules may be performed. The first and second mounting/demounting apparatuses are arranged and configured such that when the mounting/demounting unit is moved along the mounting surface, the first mounting/demounting apparatus is adapted to remove a used photovoltaic module, whereas the second mounting/demounting apparatus is adapted to insert a new photovoltaic module between two retaining surfaces. Thus, the used

photovoltaic module is replaced with the new photovoltaic module in an essentially one step and an essentially simultaneous process. The one step/simultaneous process is advantageous in that it allows replacement of thousands of square meters of photovoltaic modules every day. During insertion of the new photovoltaic module the carrier foil, and thereby the photovoltaic module itself, may advantageously be curved or bended in a transverse direction to ease insertion into the space defined between two retaining surfaces.

At least one of the mounting/demounting apparatuses is/are slidably arranged such that it may be moved relative to the mounting/demounting unit in a direction transverse to a longitudinal direction of the photovoltaic module. The mounting/demounting apparatuses may comprise one or more rotatably mounted barrels - each of said barrels being rotatable around respective centre axes. The barrels may comprise curved outer surfaces along a transverse direction onto which photovoltaic modules are adapted to be arranged. The curved outer surfaces reduce the projected width of the photovoltaic modules. A photovoltaic module having a real width of for example 40 cm may be curved in the transverse direction so that its projected width is reduced to 30-35 cm. Pre-curving the photovoltaic modules on the barrels ease a subsequent mounting of the photovoltaic module on the mounting surface of the support structure.

In a second aspect, the present invention relates to a mounting/demounting unit for use in relation to the first aspect of the present invention.

In a third aspect, the present invention relates to a method for mounting a photovoltaic module having a total thickness below 500 μιη, the method comprising the steps of moving retaining means from a retaining position to a non-retaining position, inserting at least a part of a new photovoltaic module into a space defined between two retaining surfaces, moving the retaining means from a non-retaining to the retaining position whereby the new photovoltaic module is retained between the two retaining surfaces.

Thus, the third aspect of the present invention relates to mounting of a new foil-based photovoltaic module. The new foil-based photovoltaic module is retained in position by retaining means/elements which may be implemented as spring loaded clamps. During insertion of the new photovoltaic module it may advantageously be curved or bended in a transverse direction to ease insertion into the space defined between the two retaining surfaces.

In a fourth aspect, the present invention relates to a method for demounting a photovoltaic module having a total thickness below 500 μιη, the method comprising the steps of move the retaining means from the retaining position to the non-retaining position, remove at least a part of a used photovoltaic module away from a space defined between two retaining surfaces, and move the retaining means from the non-retaining to the retaining position. Thus, the fourth aspect of the present invention relates to demounting of a used foil-based photovoltaic module. The used foil-based photovoltaic module is retained in position by retaining means/elements which may be implemented as spring loaded clamps.

In a fifth aspect, the present invention relates to a method for replacing a photovoltaic module having a total thickness below 500 μιη, the method comprising the steps of - providing a first mounting/demounting apparatus and a second mounting/demounting apparatus, removing, using the first mounting/demounting apparatus, a used photovoltaic module, and inserting, using the second mounting/demounting apparatus, a new photovoltaic module in between two retaining surfaces, whereby the used photovoltaic module is replaced with the new photovoltaic module.

The step of removing the used photovoltaic module may involve moving retaining means from retaining positions to the non-retaining positions. Similarly, the step of inserting the new photovoltaic module may involve moving retaining means from non-retaining positions to retaining positions.

According to the fifth aspect the used photovoltaic module is replaced with the new photovoltaic module in an essentially one step and an essentially simultaneous process. The one step/simultaneous process is advantageous in that it allows replacement of thousands of square meters of photovoltaic modules every day.

During insertion of the new photovoltaic module the photovoltaic module may

advantageously be curved or bended in a transverse direction to ease insertion into the space defined between two retaining surfaces.

In a sixth aspect, the present invention relates to a method for mounting/demounting a photovoltaic module having a total thickness below 500 μιη, the method comprising the step of providing a mounting/demounting unit comprising at least one mounting/demounting apparatus which, when the mounting/demounting unit is moved along the mounting surface, causes the photovoltaic module to be mounted or demounted to a support structure.

The mounting or demounting to the support structure may be accomplished by activating retaining means, said retaining means being movable between a retaining position in which it retains the photovoltaic module relative to the mounting surface and a non-retaining position in which it does not retain the photovoltaic module relative to the retaining surface.

Alternatively or in combination therewith the photovoltaic module may be mounted by an appliance of an adhesive element which retains the photovoltaic module relative to the mounting surface.

In a seventh aspect the present invention relates to a photovoltaic arrangement comprising : a support structure defining a mounting surface onto which a photovoltaic module having total thicknesses below 500 μιη is detachably mounted; and a mounting/demounting unit comprising at least one mounting/demounting apparatus which when the mounting/demounting unit is moved along the mounting surface, causes the photovoltaic module to be mounted to or demounted from the support structure.

The support structure may comprise retaining means for detachably retaining the

photovoltaic module relative to the mounting surface, the retaining means being movable between a retaining position in which it retains the photovoltaic module relative to the mounting surface and a non-retaining position in which it does not retain the photovoltaic module relative to the retaining surface.

In any of the above aspects the total thickness of the photovoltaic module may be below 250 μιη, such as below 100 μιη. Thus, the photovoltaic modules are highly flexible structures. BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be explained in further details with reference to the accompanying figures where

Fig. 1 shows a polymer foil-based photovoltaic module, Fig. 2 shows an electrical diagram of a foil-based photovoltaic module, Fig. 3 shows rows of foil-based photovoltaic modules,

Fig. 4 shows an arrangement for mounting or demounting foil-based photovoltaic modules,

Fig. 5 shows an arrangement for mounting new and demounting used foil-based photovoltaic modules, Fig. 6 shows how foil-based photovoltaic modules can be mounted, and

Fig. 7 shows how spring-loaded retaining means can be opened and closed.

While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of examples in the drawings and will be described in detail herein. It should be understood, however, that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF THE INVENTION

In its most general aspect the present invention relates to an arrangement and an associated method for mounting and/or demounting of foil-based photovoltaic modules. This includes removal of used photovoltaic modules and mounting of new photovoltaic modules in a one step process, i.e. essentially simultaneously. The arrangement and the associated method of the present invention are advantageous in that thousands of square meters of photovoltaic modules may be mounted, removed or replaced effectively and within a short period of time. The foil-based photovoltaic modules to be handled by the arrangement and method of the present invention are depicted in Fig. 1. Fig. 1 depicts an exemplifying polymer based photovoltaic module 100 comprising a carrier element 101 in the form of an organic polymer foil. On the carrier element a plurality of photovoltaic cell units 102 are provided. Each photovoltaic cell unit comprises 16 photovoltaic cells 103 which are electrically connected in series. Moreover, the units are also electrically connected in series. In order to do this, each unit 102 comprises an end-photovoltaic cell 104 which is designed such that a part of it extends between the respective two photovoltaic cells. Although not visible in Fig. 1, it will be appreciated that an interconnecting electrical conductor is provided between each of the photovoltaic cells which are electrically connected to each other. In Fig. 1, these interconnecting electrical conductors are provided in the thin white spaces between the photovoltaic cells 103.

In Fig. 1, eight photovoltaic cell units are provided. However, due to the design of the solar cell, an unlimited number of photovoltaic cell units may be provided as indicated by the infinity sign 106. Due to the topography of the photovoltaic module, it may be manufactured in an endless manner such that a user may simply cut the solar cell at a desired length and use the end cell as the positive module terminal and as the negative module terminal.

Fig. 2 depicts an electrical diagram representing the polymer based organic solar cell where N photovoltaic cell units are connected in series. Electrically each photovoltaic cell unit may be modeled by a photocurrent generator I _L 112 ^1,2 ' ^{3, "N} , a diode 114 ^1,2,3,"N described by the Shockley diode equation in parallel with a shunt resistance Rp ^{1,2,3, N} 116 ¹ ' ^{2,3, N} , and with a series resistance Rs ¹ ' ² ' ³ ' ^ llS ¹ ' ² ' ³ ' ^.

For a set of series connected solar cells, each cell experiences a voltage drop. The voltage of the full set of solar cells is the sum of the voltage drops over each cell when the same current flows through the cell.

Polymer based photovoltaic modules are typically arranged in rows as depicted in Fig. 3 thereby forming a photovoltaic power installation 300. The rows of the photovoltaic modules 301 are angled relative to ground via support structures 302 having mounting surfaces 303 in order capture maximum solar energy. The support structures 302 are secured to ground via mounting tracks 304. The overall length of the photovoltaic modules as well as the number of rows may obviously vary from installation to installation. A single photovoltaic power installation may involve several thousand square meters of active photovoltaic elements.

The polymer based photovoltaic modules can be secured to the mounting surfaces of the support structure in various ways. In an exemplifying embodiment a number of spring loaded retaining elements in the form of spring loaded clamps can be applied in order to keep photovoltaic modules in position relative to an associated mounting surface. The retaining elements may be attached to the mounting surfaces at appropriate intervals along the length of the mounting surfaces, such as at intervals varying between 25 cm and 200 cm.

Retaining elements are in a so-called retaining position when securing photovoltaic modules to an associated mounting surface. The retaining element may be shifted to a non-retaining position which allows used photovoltaic modules to be removed. Optionally, new photovoltaic modules may be inserted to replace the used modules while a retaining element is in the non-retaining position. To retain the new photovoltaic module in position the retaining element is shifted to the retaining position. It should be noted however that other types of retaining means, such as adhesives, clamps, U-shaped tracks etc., are applicable as well.

Fig. 4 depicts a mobile arrangement 400 adapted to be moved along rows of photovoltaic modules when foil-based photovoltaic modules are to be mounted or demounted. The arrangement comprises a frame structure 401 with four wheels 402-405 attached thereto. A wagon 406 being slidable along tracks 407, 408 is adapted to carry a barrel 409 of foil- based photovoltaic modules. Thus, the barrel 409 of foil-based photovoltaic modules may be moved in a two-dimensional pattern - 1) in a longitudinal direction of the rows, and 2) in a transverse direction relative to the longitudinal direction. The barrel 409 is free to roll around its center axis 410 so that photovoltaic modules may be rolled out or rolled onto the barrel. Suitable braking means (not shown) may be provided.

Fig. 5 also depicts a mobile arrangement 500 adapted to be moved along rows of

photovoltaic modules when foil-based photovoltaic modules are to be mounted and demounted simultaneously. The arrangement comprises a frame structure 501 with four wheels 502-505 attached thereto. A wagon 506 being slidable along tracks 507, 508, 509 is adapted to carry barrels 510, 511 of foil-based photovoltaic modules. Thus, the barrels 510, 511 of foil-based photovoltaic modules may be moved in a two-dimensional pattern - 1) in a longitudinal direction of the rows, and 2) in a transverse direction relative to the longitudinal direction.

The barrels 510, 511 are free to roll around their respective center axes 512, 513 so that photovoltaic modules may be rolled out or rolled onto the barrel. Suitable braking means (not shown) may be provided. It might be so that the barrel 510 carries photovoltaic modules to be rolled out (mounting), whereas barrel 511 is for collecting (demounting) photovoltaic modules.

The mobile arrangement 500 depicted in Fig. 5 is suitable for simultaneous replacement of used photovoltaic modules with new photovoltaic modules. Such as simultaneous

replacement process is advantageous in that it allows replacement of thousands of square meters of photovoltaic modules every day.

The flexible properties of the foil-based photovoltaic modules are utilized during mounting of the modules by curving the foil along its transverse direction. As an example, a foil-based photovoltaic module having a width of 40 cm is curved so that its projected width is reduced to for example 30-35 cm. The reduced projected width eases the mounting process in that the foil-based photovoltaic modules can be easily slighted in place relative to the retaining elements which may be positioned for every 50 cm along the length of the module. The transverse curving of the foil-based photovoltaic modules may alternatively be achieved by applying barrels 409, 510, 511 having correspondingly curved outer surfaces. Fig. 6 shows an example of a mounting arrangement 600 according to the present invention. In particular, Fig. 6 shows how a foil-based photovoltaic module 601 may be mounted to a support structure (not shown) using spring-loaded clamps 602-604 positioned along the edges of the foil. The foil-based photovoltaic module is coiled at structure 605 which is adapted to be moved along the support structure in the direction indicated by the arrow 606. The curved element 607, the cylindrical roll 608 and the ski-shaped member 609 move with the structure 605. As indicated in Fig. 6 the curved element 607 curves the foil along its transverse direction. The ski-shaped member 609, which moves with the structure 605, opens the spring-loaded clamp 604 by providing a down-ward oriented force on to it so that the foil is allowed to enter a region between two retaining surfaces of the clamp 604. When the ski-shaped member 609 has passed by the spring-loaded clamp 604, the clamp 604 closes and holds the foil 601 in a fixed relationship relative to the support structure. Another clamp (not visible) is positioned opposite to the clamp 604, i.e. on the opposite side of the foil. This oppositely arranged clamp is activated by a separate ski-shaped member. The rotatably mounted cylindrical roll 608 ensures that the foil is positioned correctly on the support structure. The closed spring-loaded clamps 602, 603 keep the foil in a correct position.

Fig. 7 shows an alternative arrangement 700 for opening and closing the spring-loaded clamps 701 and 702. The top portion of Fig. 7 is shown as a cross-sectional view, whereas the lower portion of Fig. 7 is a top view. The clamps 701, 702 are spring-loaded clamps where a certain amount of force is required in order to open (dotted lines) the clamps. Referring now to the lower portion of Fig. 7, the arrow 711 indicates the foil width whereas reference numerals 703-707 illustrate clamp 701 in the following different positions; 703: fully closed, 704: partly opened, 705: fully opened, 706: partly opened and 707 fully closed. Thus, reference numerals 703-707 illustrate the various states of the clamp 701 when the track 708 passes it in the direction of the arrow. The oppositely arranged track 709 has a similar effect on clamp 702 when passing it. The tracks 708, 709 may be positioned at or around the arranged of Fig. 6 involving the structure 605, the curved element 607 and the roll 608 (marked as 710 in Fig. 7). Thus, the tracks 708, 709 have a similar effect as the ski- shaped members mentioned in relation to Fig. 6 all though the tracks 708, 709 lift the clamps 701, 702 away from the foil. Also, contrary to the arrangement shown in Fig. 6 the foil-based photovoltaic modules need not to be curved in the arrangement shown in Fig. 7.

It should be noted however that the foil-based photovoltaic module can be mounted to the support structure using other means, such as for example adhesives or none spring-loaded clamping elements which are moved in and out of intervention during passage of the mounting/demounting unit. Examples of none spring-loaded clamping element involve U- shaped tracks arranged along the edges of the foil-based photovoltaic module.