DE102010014299A1 - System for converting solar energy into electric power, has control unit that deactivates and replaces solar cells with new cells, when power generated from solar cells differ with respect to target power - Google Patents

Abstract

The system has several solar cells that are arranged on tape (18). The predetermined number of solar cells along active region is activated. The power generated from the solar cells is compared with target power. The activated cells are deactivated when the generated power differ with respect to the target power. The deactivated cells are removed and replaced with new cells when the generated power differs with respect to the target power. The replaced cells are activated.

Description

Technical area

This invention relates to a novel construction of a system for generating electrical energy using solar technology based on polymer technology. A basically similar system can also be used in the generation of light by means of polymer-based components. For generating electrical energy from light or for generating light from electrical energy components are often used today, consisting of polymers or polymer-based materials or a combination of polymers and inorganic materials. Such components are z. Polymer-based solar cells and OLEDs, d. H. organic light-emitting diodes. In general, however, despite improved sealing / packaging techniques, such organic devices tend to undergo relatively rapid aging (degradation) under the influence of moisture and / or oxygen. To ensure the efficiency of systems containing such devices, therefore, these components must be frequently replaced. The present invention realizes an arrangement and method for automatic replacement of "spent", i. H. degraded building elements by a kind of production line production. The "used" Bauelemete be replaced by new components under with the help of the so-called "roll-to-roll" method. This enables large-scale applications such as solar fields or light fields to be realized with virtually constant power or constant efficiency over time.

Background and state of the art

Polymer-based solar cells serve z. For power generation, while OLEDs, d. H. organic light-emitting diodes for generating light. It is known that such organic components or components with organic components are indeed relatively inexpensive to produce in high volume and also have an acceptable for the production price efficiency, but also that they age rapidly, so their performance or their efficiency decreases rapidly. M. a. W., the affected component no longer meets the target specification in a short time. With the current state of technology and knowledge, it is questionable whether this aging problem can ever be solved in principle with organic components. It is similarly unclear whether electrical contacts can be made to such polymers or long-lasting polymer-based materials. Currently, such devices that are to be operated over a longer period, almost always hermetically encapsulated as possible. Frequently, this sealing or encapsulation is carried out in an inert gas atmosphere, which of course requires considerable time and expense. For encapsulation itself gas-tight films or layers are usually used, which have an extremely low transmission of moisture and oxygen and thus reduce the degradation of the polymer.

The problems identified have led to partial solutions, some of which are described below.

In several patents encapsulated or sealed solar cells are described in which photosensitive, photovoltaic layers are coated with a transparent material. As a material are, as I said, polymers and polymer compounds.

That's how it describes U.S. Patent 6,093,757 a compound and a method for encapsulating a solar cell, wherein particular emphasis is placed on a UV resistance of the protective layer. in the U.S. Patent 6,693,237 For the same purpose, a polymer compound is specified with which a particularly resistant protection of the solar cell is to be achieved. In the EP Application 0 658 943 a solar cell is described whose protective layer has special weather resistance. These examples are mostly individual solar cells, which are encapsulated accordingly.

Also the article "Degradation of organic solar cells" by Kenji Kawano et al. published in Solar Energy Materials and Solar Cells, Volume 90, 2006, pp. 3520-3530 , refers to the degradation, here the organic solar cells in air.

One approach is to arrange solar cells several times in the U.S. Patent 7,259,322 shown. There, a band of individual solar cells is described, in which the individual cells are electrically and mechanically connected to each other.

By means of doctor blade technology on textiles, that is to say in principle a flexible carrier, flatly applied solar cells made of polymers are included in the article "Strategies for incorporation of polymer photovoltaics into garments and textiles" by Frederik C. Krebs et al. described. The article was published in Solar Energy Materials and Solar Cells, Volume 90, 2006, pp. 1058-1067 released.

The production of OLEDs by means of the so-called roll-to-roll method is described in an article by Anil Duggal in the journal OLEDs of 11 March 2008, see http://www.grcblog.com/?p=247 : "World's first demonstration of" roll-to-roll "processed OLEDs". However, this is a message without technical details.

In the published PCT application WO 2007/115318 describes the control of the roll-to-roll production of photovoltaic cells, wherein in particular the layer thicknesses of the applied layers are controlled and controlled. The cells thus produced are then separated or separated for use.

In the EP Application 1 713 311 [0006] US-4,783,974 discloses a method and an arrangement for manufacturing electronic components by means of a roll-to-roll process, wherein the use of forming, recessed rolls in conjunction with functional, ie conductive, ink for producing printed electronic circuits is in the foreground.

None of the cited publications and publications describe or disclose the method according to the invention described in more detail below or the corresponding arrangement of the use of the roll-to-roll principle for remedying the degradation or aging problem in components for the production or use of electrical energy. Also, none of the cited publications and publications, individually or in combination, suggests such an approach.

The invention

Based on the above-described problems, the present invention has set itself the goal of degradation problems in an organic-based system for the generation or use of electrical energy, eg. As in light or solar technology, eliminate or at least minimize. So z. B. in a photovoltaic system a fairly even power output can be guaranteed. This is, in short, achieved by making the individual cells of the system by means of a pressure-like process as a continuous belt in a relatively short period of time. In this case, the "fresh" pulled out of the roll section with preferably several cells is activated immediately, d. H. used for power generation or light output. At the same time, the active cells are continuously monitored, e.g. B. by monitoring the efficiency of the photovoltaic system or the intensity of the emission field. Upon deterioration of this property (s), the used band section is turned off, i. H. out of service. Subsequently, the consumed band component is led out of the system for disposal and a new band section is activated, i. H. fed into the system parallel to this process step, the use of which begins with the shutdown of the previous or a short time thereafter. The band sections will be produced and changed intermittently preferably. However, a continuous production and an intermittent activation is feasible.

In other words, the invention is a system for converting radiant energy into electrical energy and vice versa using ribbon-shaped cells or elements having wear-susceptible organic constituents. It is characterized by the fact that the cells are produced as a band in a quasi-continuous process in the form of a roll-to-roll process and in an active area in each case a predetermined number of completed cells for energy conversion electrically switched on, d. H. is activated. In this case, an actual property of at least one activated cell is preferably monitored at short intervals and compared with a predetermined desired property. Given a predetermined deviation of the measured actual property from the desired property, the active cells will be switched off electrically and the band will be transported forward by the predetermined number of cells. In this case, the previously active lines are removed from the active area and replaced by new cells, and subsequently the latter electrically turned on or activated.

In a photovoltaic system, the cells themselves are preferably polymer-based solar cells having a transparent metal-oxide layer and a transparent film for protecting the surface.

In a light-generating system, the cells are designed as light-generating cells, in particular LEDs or OLEDs.

Furthermore, a timer can be provided in the system, which independently of or in addition to a monitored actual property of an activated cell, controls the onward transport of the band in a time-dependent manner. The measured or monitored actual property can z. B. be the power delivered and done the comparison with a predetermined target power. Alternatively, the measured actual property can be the efficiency and the comparison can be made with a predetermined desired efficiency.

Overall, the monitoring of the actual property of an activated cell and the comparison with a predetermined desired property can be carried out continuously. Likewise, the manufacturing process can be formed continuously and a storage space can be provided in front of the active area, to which the continuously produced strip is fed and is led out of the latter for the intermittent activation of the cells.

The power transmission serve according to an embodiment of the invention on or on each Cell arranged on the band electrodes, which are contacted upon activation of a cell of the active region fixed, movable metallic contacts. These electrodes may preferably be covered with a foil which, when activated, is pierced by fixed, possibly movable metallic contacts.

Furthermore, in the system is a measuring and control unit 20 provided, which controls the production of the cells, the transport of the tape and the activation of the cells located in the active area.

For the production of the cells, according to a further embodiment of the invention, at least two unwinding devices can be provided, on which there is a supply of band-shaped materials for the production of the cells. Downstream of this, a corresponding coating unit can be arranged and, behind the active region, a take-up roll for receiving the tape with inactive, used-up cells.

Controlling the system will cause the output power of the system to fluctuate only to a limited extent, which variation can be adjusted by varying the limit (s) of allowable degradation.

The advantage of such a system is also that existing printing methods and machines can be used, which both simplifies manufacturing and limits costs.

As described in detail below, the so-called roll-to-roll technology known from printing and other techniques can be used for the production of the tape with the cells for the intended purpose. Although this technology is already used for the production of OLEDs, solar cells u. Like., But only for the serial production thereof and not in the way, as it is used for the present invention. For the process presented in this invention, the roll-to-roll machine used for manufacture is an integral part of the overall system, since the polymer-based devices degrade slowly and continuously after their manufacture or activation of the solar cell, i. H. gradually lose efficiency. The fundamental difference with other solar power generating systems is the fact that in this invention the power generating medium (the solar cell) is considered as a consumable which is exchanged continuously or intermittently after a certain service life. The fact that such a system works economically and environmentally friendly is based on the fact that the consumables used to produce the solar cell can be provided very cheaply in high volumes and, because of the mainly polymeric constituents, can be disposed of in an environmentally friendly manner or even be reused.

Description of exemplary embodiments

Hereinafter, the invention will be explained in detail with reference to embodiments shown in the accompanying drawings. On the drawings show:

1a a schematic diagram of a solar cell system with the roll-to-roll principle according to the invention;

1b a part of the roller device used;

2 a solar cell tape according to the invention; and

3 - 5 the manufacture and position of the contacts on the solar cell strip.

In 1a schematically a solar cell system using the roll-to-roll principle is shown. A foil tape, here a solar cell tape 18 , is used in a roller device containing the two rollers 16 and 17 contains and in 1b is shown in more detail, manufactured and leaves this roller device in the direction of pickup roller 19 ,

This take-up roll 19 pulls the solar cell ribbon 18 into the activation area and picks up the spent solar cell ribbon. The latter is, as soon as the role is full, disposed of, ie preferably recycled.

The solar cells themselves will be in 2 shown in more detail. Here is just explained that each of the three "active" solar cells 21a to 21c one contact each 44a to 44c at the top, which also receives the activating radiation, and one contact each 45a to 45c has at the bottom. These contacts are used for power and power consumption. Furthermore, a measuring and control unit 20 provided on the one hand the connection of the solar cell system with a power grid (not shown), z. As the public grid, controls, so essentially the solar cell system turns on the network when the voltage or power of the solar cell system is sufficient and on the other hand disconnects from the grid with decreasing voltage or power. In addition, by means of the measuring and control unit 20 also a voltage / current control of the solar cell system done.

The mentioned connection of the solar cell system with the network via the connections 10 , this connection through the measuring and control unit 20 monitored and regulated. In case of power loss, this measuring and control unit gives 20 , if necessary via a computer, the signal to release the contacts 44a to 44c respectively. 45a to 45c and to replace the spent portion of the solar cell ribbon 18 ,

The efficiency of the solar cell system when exposed to sunlight can be easily monitored by the current obtained. If the measured power drops due to the degradation of the solar cell units 21a . 21b . 21c below a critical value - eg. As by contamination or material fatigue - initiated by the measuring and control unit or provided in her computer the automatic replacement of the active cells of the solar cell ribbon 14 by moving it. In the process, the spent cells will be affected by the roll movement, see 1a and 1b , led out of the active zone and fed new / fresh solar cells. For the exchange, the contacts, z. As grinding, clamping or punch contacts, in the 4 and 5 are shown solved, allowing the intended exchange.

1b shows the principle of the roll-to-roll method used, ie the part of a corresponding roller device, wherein here only the important last part of the production is shown. From a supply roll 11 , or Vorproduktionseinheit, is a band-shaped film 12 that z. B. a photosensitive material (eg., Polymer layer with n- or p-contact) and may contain a film for encapsulation, unwound. From another supply roll 13 , or pre-production unit is a second band-shaped film 14 unwound, the z. B. may contain a further photosensitive material (polymer with p- or n-contact) and a film for encapsulation. Between the two slides 12 and 14 one or more further unwinding devices can be provided for further band-shaped films, or coating units for the above-mentioned films.

In fact, in most cases more than two unwinding devices or multi-layer coating units will be present since conventional solar cells or OLEDs consist of more than two layers of material. So z. B. the photosensitive layer or the luminescent layer usually provided with a protective layer. Their unwinding device, to stay with the example, would then be above the first roll 11 arranged or the encapsulation layer would already be part of the film 12 , If an insulating layer is to be provided between the photosensitive layer or the luminescent layer, its unwinding device would be between the first supply roll 11 and the second supply roll 13 in 1 arranged.

The two slides 12 and 14 are now using the roles 15 . 16 and 17 connected, wherein one or more of these roles can be heated. The resulting foil tape 18 , z. B. a solar cell tape, leaves the roller device in the direction of the arrow. This is the first step of the inventive method.

2 shows the solar cell ribbon 18 in a spread state in a top view. These are individual solar cells 21a to 21c arranged as similar units. In operation, the solar cell ribbon is moved in the direction of the arrow, in each case a predetermined number, z. B. three solar cells as in 1 shown, are active, ie are in the range activating radiation. The foil tape lies on and gets along isolated slide rails 22 moved there and also isolated from Niederhaltern 23 on these rails 22 held.

After removing the film, the next step is the solar cell strip 14 (or the film) according to the design of the solar cells 21a to 21c contacted. The extension or movement of the solar cell strip can be realized by rolling at the beginning and end of the slide rails. Similar to a writable film of an overhead projector, the solar cell strip can then be transported further if the degraded solar cell units lose their power, and thus new (unused) solar cell units can be transported 21a . 21b . 21c over the slide rails 22 be confiscated.

In the 3 to 5 Schematically different designs of solar cells are shown as units 21a . 21b . 21c in the extended solar cell strip 14 are located.

3 shows a single one of the polymer-based solar cell units 21a . 21b . 21c of the solar cell strip in cross section. The active layer 31 consists of an active polymer material. For example, poly (3, 4-ethylene dioxythiophene) -poly (styrene sulfonic acid) (PEDOT: PSS) or z. Example, a combination of PEDOT-PSS with thin layers of conjugated polymer / methanofullerene mixed layers or poly (fluorene) -based hole transport layers, which can contribute to an increase in performance of the polymer-based solar cell.

On top of this active layer 31 is a first electrode 32 arranged, which is transparent or semitransparent, so that incident light or incident radiation is the active layer 31 can reach. Frequently, for such an electrode transparent, conductive metal-oxide films ( so-called TCOs) because of their excellent conductivity properties and their high transparency in the visible spectral range used. The first electrode 32 serves as an anode, for example. On the bottom of the active layer 31 is a second electrode 33 arranged, which does not need to be transparent and in the example serves as a cathode. The films or films used as protection for the entire assembly 35 and 36 are also shown in the overview. These films seal the polymer-based solar cells especially against moisture and oxygen. These are the two slides 35 and 36 by means of the in 1b shown applied roll-to-roll method and at their side of the solar cell seams by means of two seals 34 and 34 ' glued or welded. This can be z. B. by an applied (not shown) adhesive or with an ultrasonic, laser or hot air welding done.

This is the otherwise unprotected solar cell through the films or films 35 and 36 sealed.

In this way, that arises in the 1a and 1b shown and described in connection solar cell ribbon. However, this still lacks the contact to the outside to decrease the electrical power.

One way for this contacting is in 4 shown. Two appropriately trained, preferably metallic, sharpened contacts 44 respectively. 45 are pressed at a suitable point on the solar cell strip and pierced there the respective film 36 respectively. 35 , Then each of these contacts forms 44 respectively. 45 a conductive connection with the corresponding electrodes 32 and 33 and thus allows the transmission of electrical power.

In 5 a second possibility is shown, like the two electrodes 32 and 33 , where yes the generated electrical power is available to be connected to the outside. These are a first connection line 51 from the first electrode 32 on one side of the cell and correspondingly a second connection line 52 from the second electrode 32 on the other side of the cell led to the outside.

The first connection line 51 is preferably, at least where it is in the active layer 31 is transparent or at least translucent designed to not adversely affect the yield of the solar cell. You can z. B. before applying the film 36 already on the solar cell facing side of the film 36 be arranged so that they are the first electrode when applying the film 32 contacted. Accordingly, the second connection line 52 also already on the solar cell side facing the film 35 be attached so that they are the second electrode when joining the films 33 contacted. As in the example of 5 the connection line 51 and 52 stand out laterally from the films, these electrodes without puncturing the film, z. B. be contacted by grinding or clamping contacts, which then similar to in 4 shown allows a power transmission.

A similar method as described in the previous paragraph may also be used to generate light by LED or OLED arrays. Here, not an array of solar cells, but an array of flexible LEDs or OLEDs by means of the beschribenen roll-to-roll method is generated. Subsequently, the array, similar to the examples in the 4 respectively. 5 are described, contacted. In the next step, power is now supplied to the system, thus initiating the generation of light via the LEDs by means of spontaneous emission.

After degradation of the component, the contacts are released again from the object. Subsequently, by the mechanism already described, the film with the degraded LEDs or OLEDs from the central region of the system by the roller movement led out and at the same time are "fresh", d. H. new LEDs or OLEDs fed into the system. Re-contact allows the system to resume normal operation while the spent LEDs or OLEDs are removed from the system.

It is obvious that the described system and method can be modified and extended in many ways. It is thus possible, for example, to supply the "spent" cells or elements directly to a recycling process in a reprocessing plant. Ideally, even a kind of closed circuit can be provided, in which the reprocessing of the elements or cells takes place by means of the roll-to-roll method according to the invention. Thereafter, the renewed elements or cells can in turn be supplied to the active circuit or introduced into it.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 6093757 [0005]
• US 6693237 [0005]
• EP 0658943 [0005]
• US 7259322 [0007]
• WO 2007/115318 [0010]
• EP 1713311 [0011]

Cited non-patent literature

• "Degradation of organic solar cells" by Kenji Kawano et al. published in Solar Energy Materials and Solar Cells, Volume 90, 2006, pp. 3520-3530 [0006]
• "Strategies for incorporation of polymer photovoltaics into garments and textiles" by Frederik C. Krebs et al. described. The article was published in Solar Energy Materials and Solar Cells, Volume 90, 2006, pp. 1058-1067 [0008]
• http://www.grcblog.com/?p=247 [0009]

Claims (13)

System for the conversion of radiant energy into electrical energy and vice versa using band-shaped cells or elements which have wear-susceptible organic constituents, characterized in that - the cells act as a band ( 18 ) are produced in a quasi-continuous production process in the form of a roll-to-roll process, - in an active area in each case a predetermined number of completed cells for energy conversion electrically switched on, that is activated, - an actual property of at least one activated cell is preferably monitored at short intervals and compared with a predetermined desired property, - in the case of deviation of the measured actual property of the desired property by a predetermined difference, the active cells are electrically switched off, - then the band ( 18 ) is transported forward by the predetermined number of cells, whereby the previously active cells are removed from the active area and replaced by new cells, and - then the new cells are electrically switched on, ie activated. System according to claim 1, characterized in that the cells are polymer-based solar cells, in particular a transparent metal oxide layer ( 31 ) and a transparent film ( 32 ) to protect the surface. System according to claim 1, characterized in that the cells are designed as light-generating cells, in particular LEDs or OLEDs. A system according to claim 1, characterized in that a timer is provided which independently of or in addition to a monitored actual property of an activated cell controls the further transport of the tape time-dependent. System according to claim 1, characterized in that the measured actual property is the power output and the comparison is made with a predetermined desired power. System according to claim 1, characterized in that the measured actual property is the efficiency and the comparison is carried out with a predetermined desired efficiency. System according to claim 1, characterized in that the monitoring of the actual property of an activated cell and the comparison with a predetermined desired property is carried out continuously. System according to at least one of the preceding claims, characterized in that the manufacturing process is formed continuously and in front of the active area a storage space is provided to which the continuously produced strip is supplied and from which it is led out for the intermitterende activation of the cells. System according to at least one of the preceding claims, characterized in that each cell of the belt has electrodes ( 32 . 33 ), which, upon activation of a cell, are arranged in the active region in a fixedly arranged, movable metallic contacts ( 44 . 45 ) are contacted. System according to claim 9, characterized in that the electrodes ( 32 . 33 ) of a cell with a foil ( 35 . 36 ) are covered, which, when activated by the stationary, movable metallic contacts ( 44 . 45 ) are pierced. System according to at least one of the preceding claims, characterized in that a measuring and control unit 20 is provided, which controls the production of the cells, the transport of the band and the activation of the cells located in the active region. System according to at least one of the preceding claims, characterized in that - at least two unwinding devices ( 11 . 13 ) are provided on which there is a supply of band-shaped materials for the production of the cells, - this downstream, a coating unit is provided, which consists of several roles ( 15 . 16 . 17 ), and - behind the active area a take-up roll ( 19 ) for receiving the tape ( 18 ) is arranged with the inactive, spent cells. System according to claim 12, characterized in that at least one of the rollers ( 15 . 16 . 17 ) of the coating unit is heated.

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