The present invention pertains to a photovoltaic panel.
The present invention further pertains to a method of manufacturing a photovoltaic panel.
Perovskites, are promising materials for use as a photovoltaic material in a photovoltaic layer of a photovoltaic panel. The name ‘perovskites’ is used to denote materials having an ABX3 crystal structure. The most commonly studied perovskite for photovoltaic cells is methylammonium lead trihalide (CH3NH3PbX3, where X is a halogen atom such as iodine, bromine or chlorine), with an optical bandgap between 1.5 and 2.3 eV depending on halide content. Another example is formamidinum lead trihalide (H2NCHNH2PbX3) having bandgaps between 1.5 and 2.2 eV. So far it has not been possible to find suitable alternatives for the component lead. Tin-based perovskite photovoltaic materials such as CH3NH3SnI3 have also been investigated. Probably these Tin based perovskite will in the future, be combined with Lead based perovskites, either in mixtures or as separate layers in a tandem or even triple configuration. A common concern is that lead and also Tin as a component of the perovskite materials may enter the environment in case defects are present in the panel.
It is an object of the invention to provide a photovoltaic panel having a construction that mitigates the risk that lead and or tin present in the photovoltaic layer enters the environment.
It is a further object of the invention to provide a method of manufacturing such a photovoltaic panel.
A photovoltaic panel according to the object specified above, is provided as defined in claim 1. The photovoltaic panel as claimed therein comprises in the order named a first electrically conductive layer, a photovoltaic layer of a perovskite photovoltaic material, a second electrically conductive layer, and a protective coating that at least forms a barrier against moisture. It is noted that any of these layers may be one of a stack of similar layers. Therein the individual layers in the stack of similar layers may be formed of mutually different materials and have mutually different properties. For example, the first /second electrically conductive layer may be one of a stack of first/second electrically conductive layers. The photovoltaic layer of a perovskite photovoltaic material may be one of a stack of photovoltaic layers of a perovskite photovoltaic material. Individual layers in the stack of photovoltaic layers may be formed of a respective material, for example of perovskite photovoltaic materials of mutually different types or of mutually different compositions of perovskite photovoltaic materials. For example two or three or more of such photovoltaic layers may be provided. A stack of one or more photovoltaic layers of a perovskite photovoltaic material may further comprise one or more layers of another photovoltaic material. The protective coating may also be provided as a stack of layers, for example a stack of inorganic layers of a different type alternating each other, for example of mutually different ceramic materials that alternate each other. In addition to the above-mentioned layers other layers may be present, for example one or more hole injection layers, one or more hole transport layers, one or more electron injection layer and/or one or more electron transport layers. The first electrically conductive layer of the photovoltaic panel is partitioned along first partitioning lines extending in a first direction. In case the first electrically conductive layer is one of a stack of similar layers, then all layers of this stack are partitioned along these first partitioning lines. This also applies to any other electrically conductive layers, such as hole/electron injection/transport layers between the first electrically conductive layer and the photovoltaic layer. Furthermore, the second electrically conductive layer and the photovoltaic layer are partitioned along second partitioning lines extending in the first direction and along third partitioning lines extending in a second direction different from the first direction. In case the second electrically conductive layer is one of a stack of similar layers, then all layers of this stack are partitioned along these second partitioning lines and third partitioning lines. This also applies to any other electrically conductive layers, such as hole/electron injection/transport layers between the second electrically conductive layer and the photovoltaic layer. Likewise, if the photovoltaic layer is one of a stack of layers then all layers of this latter stack are partitioned along these second partitioning lines and third partitioning lines. The first and the second partitioning lines alternate each other and a space defined by the first and the third partitioning lines is filled with a protective filler material forming a barrier against moisture. Therewith photovoltaic cells are defined that are encapsulated by the protective material of the coating and the protective filler material.
In addition to the above-mentioned sets of partitioning lines, further partitioning lines may be provided at oblique angles with respect to the earlier mentioned partitioning lines that partition the top layers of the photovoltaic panel into triangular portions, for example up to but not including the bottom electrode. This additional partitioning facilitates folding the photovoltaic panel in a three dimensional shape. The spaces formed between the triangular portions may be filled with a protective material. If necessary additional conductive elements may be provided to electrically interconnect mutually separate portions.
The encapsulation of the perovskite photovoltaic material in photovoltaic cells substantially limits an amount of the photovoltaic material that could enter the environment in case of a defect. The protective material is part of an encapsulation that encapsulates the first electrically conductive layer, the second electrically conductive layer and the photovoltaic layer. The encapsulation forms a barrier against moisture, therewith effectively protecting against an ingress of moisture that in contact with the photovoltaic layer would result in a degradation of the latter.
The encapsulation may for example additionally comprise a substrate of the panel. If the substrate as such does not form a sufficiently effective barrier for moisture, it may be provided with additional barrier layer. In an embodiment the first electrically conductive layer may serve as a substrate. Alternatively, the first electrically conductive layer may be a layer on a substrate.
A method according to the further object is claimed in claim 9. The method of manufacturing a photovoltaic panel subsequently comprises:
Providing a first electrically conductive layer that is partitioned along first partitioning lines extending in a first direction;
Providing at least one photovoltaic layer of a perovskite photovoltaic material, the at least one photovoltaic layer being partitioned along second partitioning lines extending in the first direction;
Providing a second electrically conductive layer that electrically contacts the first electrically conductive layer along fourth lines in the first direction;
Providing a protective material into spaces defined by second partitioning lines extending in the first direction, and by third partitioning lines extending in a second direction different from the first direction and which spaces partition the second electrically conductive layer and the photovoltaic layer wherein respective ones of the fourth lines are arranged between respective ones of the first partitioning lines and a respective nearest one of the second partitioning lines;
Providing a protective material as a protective coating layer therewith providing a plurality of photovoltaic cells having a respective encapsulated portion of the photovoltaic layer.
An embodiment of the method may further comprise the step of inspecting individual photovoltaic cells of the plurality of photovoltaic cells. Upon detection of a defect of one of the individual photovoltaic cells, the photovoltaic material contained in the defect cell may be removed. Therewith it also is avoided that photovoltaic material in the defect photovoltaic cell can enter the environment.
The photovoltaic panel obtained therewith is characterized in that it comprises a space free from photovoltaic material that is bounded by a wall of protective material to an area defined by a pair of mutually subsequent first partitioning lines and a pair of mutually subsequent third partitioning lines.
As an alternative, upon detection of defects, it may be decided to withdraw the defect product from the production line, for example in case it is detected that the product comprises more than a predetermined number of defects, for example if more than one defect occurs in a serial arranged subset of the photovoltaic cells.
As noted above, a layer may comprise two or more sublayers. For example the photovoltaic layer may be provided as a bilayer of a p-type and an n-type organic material and/or as sublayers sensitive for mutually different ranges of the solar spectrum. Also an electrode layer may further be provided as two or more layers, for example a first sublayer serving as a bulk layer and a second sublayer serving to provide a desired workfunction.
In addition further layers and other elements may be present in the photovoltaic plane, for example a hole injection layer, an electron injection layer, electric insulation layers, a mechanical support layer, electrically conductive elements, sensor elements e.g. for diagnostic purposes and the like.
In an embodiment, the photovoltaic panel comprises a planarizing layer, e.g. a resin layer having a thickness in the range of 0.1 to 100 micron, between the second electrically conductive layer and the protective coating. Therewith the encapsulation properties of the protective coating are improved.
For an optimal sealing, this planarizing layer is provided preferably in a manufacturing process preferably before the (laser) structuring of the second electrodes to ensure the good sealing of the elements.
As becomes apparent from the description the wording “line” is not intended in the purely mathematical sense of a geometrical object having only a length and no other dimensions, but as an interruption in the material having a length and a finite two-dimensional cross-section with dimensions that are substantially smaller than its length, e.g. at most 0.01 times its length.
These and other aspects are described in more detail with reference to the drawing. Therein:
Like reference symbols in the various drawings indicate like elements unless otherwise indicated.
As shown in particular in
As also shown in
As can be seen in
As mention above, only a portion of the photovoltaic panel is shown in
In the embodiment shown, the photovoltaic panel 1 includes the substrate 5 as an additional layer. The substrate 5 may contribute to the encapsulation of the photovoltaic cells and provide for a mechanical reinforcement. In addition or alternatively, the substrate may serve as electrical conductor, to electrically connect one or both electrically conductive layers to external conductors. Mechanical reinforcement may for example be provided by a substrate layer of glass, a metal or a polymer. To serve as a moisture barrier, the substrate may for example include one or more barrier layers, e.g. including one or more inorganic layers, optionally alternated with an organic decoupling layer. To provide for electrical conduction, the substrate may for example comprise one or more metal layers, for example a par of metal layers arranged on mutually opposite sides of an insulating layer. A substrate layer may provide more than one of the above-mentioned functions. For example a glass layer may serve as a moisture barrier and provide for mechanical support, and a metal layer may provide for these functions and additionally serve as an electrical conductor. In an embodiment the first electrically conductive layer 10 may serve as a substrate. In that case an additional moisture barrier material may be provided in the spaces formed by the first partitioning lines L11, L12 etc. and/or as one or more barrier layers at a side of the first electrically conductive layer 10 opposite the photovoltaic layer 20. In a manufacturing process, the photovoltaic panel may for example be released from a carrier used during the manufacturing process, or such carrier may be dissolved at the end of the manufacturing process.
In this embodiment one or more of the third partitioning lines L31, L32 extend through the first electrically conductive layer 10 and therewith also partition the first electrically conductive layer 10.
As set out above,
In embodiments, a subset of the third partitioning lines may be provided as third partitioning lines L31, L32 that extend through the first electrically conductive layer 10 as shown in
It is advantageous if at least a subset of the third partitioning lines L31, L32 have a depth bounded by the first electrically conductive layer 10. Therewith mutually neighboring cells in the direction D1 can serve as a shunt for each other, should one of them be dysfunctional. This is schematically illustrated in
In
In operation photovoltaic currents I1, I2, I3 of substantially equal strength will flow in the second direction D2.
In this embodiment one or more of the third partitioning lines L31, L32 extend through the first electrically conductive layer 10 and therewith also partition the first electrically conductive layer 10. This embodiment is provided with transverse electrically conductive elements T411, . . . , T41m, . . . , T41n; T421, . . . , T42m, . . . , T42n arranged between a respective first partitioning line L11; L12 and a respective subsequent second partitioning line L21; L22. The transverse electrically conductive elements electrically connect the second electrically conductive layer 30 with the first electrically conductive layer 10 and therewith are an alternative for the electrical connections as provided by the electrically conductive material in the spaces defined by the fourth partitioning lines in the embodiment of
A method of manufacturing a photovoltaic panel of
Therein
The partitioned first electrically conductive layer 10 may be provided in a single step, for example by a masked deposition process, or by printing. Alternatively the partitioned first electrically conductive layer 10 may be provided in a first substep as a continuous layer, followed by a patterning process in a second substep, e.g. by etching, mechanical removal or by ablation with a laser. The lines may have a width w1 depending on further processing steps. For example, if the width w1 is substantially large, e.g. 1 micron or larger, a sufficient electrical insulation is provided by photovoltaic material to be applied in a subsequent step. A smaller width w1 is possible if an insulating material is provided into the removed regions of the first electrically conductive layer 10.
In an alternative embodiment, the spaces defined by the third partitioning lines L31, L32, may extend partly or fully through the first electrically conductive layer 10.
In a further alternative embodiment a protective material may be provided into the spaces defined by the second and third partitioning lines L21, L22 L31, L32 before applying the protective coating, for example using a different protective material than the material used for the coating.
In an embodiment, the spaces defined by the second and third partitioning lines L21, L22 L31, L32 may be applied by a controlled deposition process of the second electrically conductive layer 30 and/or the photovoltaic layer 20, e.g. by printing or by a masked deposition method. Therewith the spaces are already formed in the deposition process. Alternatively the openings may be provided subsequent to the deposition process by a removal step, such as etching, and laser drilling or cutting. Also combinations are possible, for example the spaces in the photovoltaic layer 20 may be formed subsequent to its deposition and the spaces in the second electrically conductive layer may be formed in the deposition process.
In an optional subsequent step S5 as shown in
In the subsequent step S6 the photovoltaic material contained in the defect cell, e.g. C22, may be removed for example by treatment with a laser 120 controlled by the signal processing device 100. Also other means may be used. For example the material contained in the cell may be removed by mechanical interaction or by an etching step. If the defect is sufficiently large, the photovoltaic material contained in the defect cell, e.g. C22, may be removed by rinsing the cell with a liquid, such as water. Also the step of rinsing may be applied as an additional step, for example subsequent to the laser treatment step as shown in
Upon completion of step S6, a photovoltaic panel is obtained as shown in
Number | Date | Country | Kind |
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17183569.7 | Jul 2017 | EP | regional |
Filing Document | Filing Date | Country | Kind |
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PCT/NL2018/050521 | 7/26/2018 | WO | 00 |