DE102015120521A1 - Bifacial photovoltaic module - Google Patents

Abstract

In various embodiments, a bifacial photovoltaic module is provided. The bifacial photovoltaic module (100, 200, 300) comprises a laminate (138) with a plurality of solar cells (136) having a photosensitive front (160) and a photosensitive back (150), wherein between each two solar cells (136) a translucent Cell gap (142) is provided; and a module rear wall (124) secured to at least two side edges of the laminate (138) with translucent openings (220), the module rear wall (124) having a plurality of reflector struts (230) arranged below the cell columns (142), the translucent openings (220). below the solar cells (136) and reflect incident light from the front to the cell back.

Description

The invention relates to a bifacial photovoltaic module.

A photovoltaic module usually has a plurality of photovoltaic cells electrically coupled to each other. The photovoltaic cells are usually arranged side by side within a photovoltaic module at a distance from each other, so that between each two adjacent photovoltaic cells, a cell gap is formed, which is usually filled with a transparent encapsulating material.

The light passing through the cell gap, which thus does not hit the light incident side of the photovoltaic cells, does not contribute to the performance of a photovoltaic module.

For this reason, various developments have been made to harness this light. So it is possible to increase the power of a photovoltaic module by capturing light in the cell columns. In today's photovoltaic module, approximately 30% of the light striking the cell slits is re-applied to the photovoltaic cells by total reflection on the top glass cover of the photovoltaic cells. However, light scattered behind the photovoltaic cells is lost and absorbed in the backside metallization.

By default, a transparent encapsulation with a highly reflective film on the back is used. Alternatively, an attempt can be made to address this problem by using a white encapsulation (eg EVA: ethylene vinyl acetate). However, the use of such an encapsulation has the disadvantage that the lamination process commonly used must be controlled so that no white encapsulation material surrounds the cell edge of a respective photovoltaic cell.

This is usually costly and expensive and can not be used for bifacial cell and module designs because no light can reach the cell backside.

A so-called bifacial solar cell is, for example, in DE 10 2004 049 160 B4 described.

According to various embodiments, the photovoltaic module is mechanically stabilized by a module rear wall and increases the electrical power provided by the respective photovoltaic cell.

Various embodiments relate to a bifacial photovoltaic module comprising a laminate having a plurality of solar cells with a photosensitive front and a photosensitive back. The plurality of solar cells are electrically coupled together in the laminate and embedded in an encapsulating material. In each case between two solar cells, a translucent cell gap is provided. Furthermore, a first transparent cover is provided over the encapsulating material covering the front of the plurality of solar cells. Furthermore, a second transparent cover is provided over the encapsulating material covering the back of the plurality of solar cells.

Furthermore, the bifacial photovoltaic module has a module rear wall with light-permeable openings attached to the laminate on at least two side edges of the laminate. The module rear wall has a plurality of reflector struts arranged below the cell gaps, which delimit light-transmitting openings below the solar cells.

Illustratively, the module rear wall has a grid, for example, with openings corresponding essentially to the shape of the solar cells. The grid struts which bound the openings are, for example, dimensioned such that their width corresponds at least to the width of a respective cell gap (preferably wider in order to ensure the light capture in obliquely). The back of the module is located below the laminate below the solar cells, so that in a bottom view, the mesh struts substantially cover the cell gaps (and possibly even a minor portion of the solar cells) and the openings are underneath the solar cells extend laterally into the cell gaps.

As a reflector strut may be understood an elongated structure having small width and / or thickness, with others: rod-shaped structure; which has a high reflectivity with respect to light, for example a diffuse reflectivity of more than 50%, preferably a diffuse reflectivity of more than 70%, optimally a diffuse reflectivity of more than 90%.

The module backplane forms a protective structure for the laminate and, in addition, can improve the performance of the photovoltaic module and mechanically stabilize the photovoltaic module. Thus, a protective, performance-enhancing and mechanically stabilizing property can be realized in one component.

In various embodiments, the bifacial photovoltaic module may further comprise a plurality of frame profiles. A photovoltaic module may preferably be two on opposite sides or four frame profiles. The frame profiles can be interconnected and form a circumferential module frame.

The frame profiles are preferably arranged at a right angle to the module rear wall. The module rear wall is arranged by means of the frame profiles at a distance from the laminate and connected to the laminate. This allows a secure attachment of the laminate with the module rear wall and the photovoltaic module as a whole.

In one embodiment, the module rear wall is adhesively bonded to at least one outer edge and / or the back of the laminate. This allows a reliable positioning of the reflector struts below the cell gaps, so that they can not be moved, for example, in a mechanical load of the photovoltaic module in operation. This enables optimum operation of the photovoltaic module according to the manufacturing specifications.

In yet another embodiment, the module rear wall has a plurality of spacers arranged between the reflector struts and the cell gaps. The spacers can ensure a minimum distance between the reflector struts of the module rear wall and the back of the laminate, so that the distance is subject to no or substantially no fluctuations, for example, during a mechanical load of the photovoltaic module in operation. This allows a mechanical stabilization of the photovoltaic module.

In yet another embodiment, the plurality of spacers are in contact with the back side of the solar cell laminate. The surface of the spacers in contact with the back is flat. This allows mechanical stabilization of the laminate, preferably via adhesive contacts, and deflection prevention for the laminate. The solar cells are not damaged by the spacers, since the spacers do not touch the solar cells, but are arranged below the cell gaps.

In yet another embodiment, the solar cells are arranged in a plurality of rows and columns, and the plurality of spacers are arranged below crossings of cell columns.

In yet another embodiment, the surface shape of the spacers located in contact with the rear side is adapted to the surface shape of the crossing points. This allows optimal stabilization of the photovoltaic module without impairing the optical properties or the efficiency of the photovoltaic module.

In yet another embodiment, the reflector struts have a diffusely reflecting surface facing the rear side. This allows reflection of the light incident through the cell gaps on the reflector struts toward the photosensitive backside of the bifacial solar cells, thereby increasing the efficiency of the photovoltaic module.

In yet another embodiment, the reflector struts have an albedo of at least 50%, for example at least 90%.

In yet another embodiment, the laminate facing surface of the reflector struts is white.

In yet another embodiment, the reflector struts are designed such that at least a portion of the light that passes through at least one cell gap of the plurality of cell gaps is reflected onto the rear sides of the solar cells. This allows reflection of the light incident through the cell gaps on the reflector struts toward the photosensitive backside of the bifacial solar cells, thereby increasing the efficiency of the photovoltaic module.

In yet another embodiment, the reflector struts are disposed at a distance of several cm, for example in a range of about 1 cm to about 10 cm, from the backside of the laminate.

In yet another embodiment, the gap width of at least one cell gap of the plurality of cell gaps is in a range of about 3 mm to about 50 mm.

In yet another embodiment, at least a portion of the plurality of spacers is adhesively bonded to the back of the laminate. This allows a mechanical stabilization of the photovoltaic module.

In yet another embodiment, the laminate has a glass cover on the back. This causes a mechanical protection of the solar cells with respect to the module rear wall, in the event that the photovoltaic module is deflected.

In a further embodiment, the frame profiles and the module rear wall are formed in one piece. This allows a simple and durable structure, since a tight connection between the frame profiles and the module back wall is not required.

In another embodiment, the frame profiles and the module rear wall are separate and interconnected pieces. This makes it possible to form the frame profiles and the module rear wall in different methods and from different materials, for example with different optical and / or electrical properties. This allows the frame profiles and the module backplane to be optimized independently of each other.

In yet another embodiment, at least two opposing frame profiles have openings for improved air circulation between the module rear wall and the laminate.

In yet another embodiment, the frame profiles and / or the module rear wall are formed from plastic.

In yet another embodiment, the frame profiles and / or the module rear wall are formed from sheet metal.

In yet another embodiment, the frame profiles or the module rear wall have at least one mounting structure formed on an outer edge of the frame profiles for fastening, for example two mounting structures on opposite outer edges of the frame profiles or the module rear wall for fastening the photovoltaic module. This allows easy installation of the photovoltaic module.

In yet another embodiment, the mounting structure has a Klemmfalz, a plurality of openings or a plurality of holes for fastening. In various embodiments, the bifacial photovoltaic module has a plurality of bifacial photovoltaic modules according to an embodiment described above. The plurality of bifacial photovoltaic modules are fastened together by means of the mounting structures.

In other words, in various embodiments, the photovoltaic module has a plurality of bifacial photovoltaic modules with two mounting structures on opposite outer edges of the frame profiles or the module rear wall for fixing each of a photovoltaic module, wherein the mounting structures have a Klemmfalz or openings for fastening, and wherein the plurality of bifacial photovoltaic modules are fastened together by means of the mounting structures.

In yet another embodiment, the frame profiles have at least two mutually offset mounting structures, for example, two opposite frame profiles on two staggered mounting structures on.

In one embodiment, the mounting structures of the bifacial photovoltaic modules are arranged offset in each case such that the plurality of bifacial photovoltaic modules are arranged flat to each other.

In other words: In various embodiments, in each case one photovoltaic module has two opposite frame profiles, the mutually staggered mounting structures, wherein the mounting structures of the plurality of bifacial photovoltaic modules are each staggered such that the plurality of bifacial photovoltaic modules to each other evenly arranged are.

Embodiments of the invention are illustrated in the figures and are explained in more detail below.

Show it

1 a cross-sectional view of a portion of a bifacial photovoltaic module according to various embodiments;

2A , B are schematic views of a bifacial photovoltaic module according to various embodiments;

3 a view of a portion of a bifacial photovoltaic module according to various embodiments;

4 schematic cross-sectional views of reflector struts of a bifacial photovoltaic module according to various embodiments; and.

5 a bifacial photovoltaic module with multiple bifacial photovoltaic modules according to various embodiments.

In the following detailed description, reference is made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology such as "top", "bottom", "front", "back", "front", "rear", etc. is used with reference to the orientation of the described figure (s). Because components of embodiments can be positioned in a number of different orientations, the directional terminology is illustrative and is in no way limiting. It should be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. It is understood that the features Unless specifically stated otherwise, the various exemplary embodiments described herein may be combined. The following detailed description is therefore not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims.

As used herein, the terms "connected," "connected," and "coupled" are used to describe both direct and indirect connection, direct or indirect connection, and direct or indirect coupling. In the figures, identical or similar elements are provided with identical reference numerals, as appropriate.

For example, the physical quantities used herein relating to optical properties may be wavelength dependent so that they are understood to mean values averaged over the wavelength range of visible light (eg, 400 nm to 800 nm).

In various exemplary embodiments, a photovoltaic cell, for example a solar cell, is understood to mean a device which has radiant energy of predominantly visible light and infrared light (for example at least part of the light in the visible wavelength range of approximately 300 nm to approximately 800 nm; that in addition also ultraviolet (UV) radiation and / or infrared (IR) radiation can be converted to about 1150 nm), for example from sunlight, directly converted into electrical energy by means of the so-called photovoltaic effect.

In various exemplary embodiments, a photovoltaic module, for example a solar module, is understood to mean an electrically connectable device with a plurality of photovoltaic cells, for example a plurality of solar cells (which are interconnected in series and / or in parallel), and optionally with weather protection (for example glass). , an embedding and a framing are connected.

1 shows a cross-sectional view of a portion of a bifacial photovoltaic module according to various embodiments.

Various embodiments relate to a bifacial photovoltaic module 100 , wherein a section of an edge portion of such a solar cell module 100 in 1 is shown.

The photovoltaic module 100 has a laminate 138 with several electrically (in series and / or parallel) coupled solar cells 136 with a photosensitive front 160 and a photosensitive back 150 that the front 160 opposite.

The several solar cells 136 are in an encapsulating material 132 embedded. The encapsulating material 132 For example, from ethylene vinyl acetate, EVA, is on the front 160 and the back 150 the solar cells 136 arranged and surrounds the solar cells 136 essentially complete, although still an electrical contact of the solar cells 136 through the encapsulating material 132 is made possible through.

Over the encapsulating material 132 is a first transparent cover 130 provided, which is glued, for example, on the encapsulating material, and which the front sides 160 the solar cells covered.

On the first transparent cover 130 opposite side of the encapsulating material 132 is a second transparent cover 134 over the encapsulating material 132 provided, for example, also glued to this, wherein the second transparent cover 134 the backs 150 the solar cells covered. The second transparent cover 134 is for example a glass cover.

The solar cells 136 are arranged to each other such that in each case between two solar cells 136 a translucent cell gap 142 is provided. The gap width of at least one cell gap 142 the multiple cell column 142 is in a range of about 3 mm to about 50 mm. In various embodiments, the solar cell 136 have the following dimensions: a width in a range of about 5 cm to about 50 cm, a length in a range of about 5 cm to about 50 cm, and a thickness in a range of about 50 μm to about 300 μm.

In various embodiments, the solar cells form 136 , the encapsulating material 132 , the first transparent cover 130 and the second transparent cover 134 a laminate 138 with solar cells, also referred to as module laminate 138 ,

Light (in 1 illustrated by means of the arrow 140 ) falls from a light source coming to the front 160 the solar cells 136 one. Light behind the photovoltaic module 100 is backblasted (Albedo), at least partially falls on the back 150 the solar cells 136 one.

Furthermore, the bifacial photovoltaic module has one with the laminate 138 at least two Side edges of the laminate, for example, three or four side edges of the laminate, for example, opposite side edges of the laminate, attached module backplane 124 on.

The module back wall 124 has several below the cell columns 142 arranged reflector struts, the translucent openings below the solar cells 136 limit (see also 2 ). Through the translucent openings backscattered light (albedo) at least partially on the back 150 the solar cells 136 come to mind.

The reflector struts of the module rear wall 124 defining the openings may be formed such that at least a portion of the light passing through at least one cell gap 142 the multiple cell column 142 passes on the backs 150 the solar cells 136 is reflected.

In other words, the reflector struts are designed such that at least part of the light passing through at least one cell gap 142 the multiple cell column 142 passes through, on the reflector struts on the backs 150 the solar cells 136 is reflected, that is deflected towards the back.

By using a bifacial solar cell 136 in a solar cell module or photovoltaic module 100 with two transparent covers 130 . 134 For example, a glass-glass solar cell module may have the initial drawback of power loss due to light scattering behind the solar cell 136 be used deliberately advantageous. To the light scattering behind the bifacial solar cell 136 To reinforce, the reflector struts 124 behind the solar cells 136 be colored white and the laminate 138 can be run or be transparent. The deeper the cell gap 142 between the solar cells 136 is, the more light can be from the laminate 138 be caught because the opening angle of the light scattering cone, which can still escape, is getting smaller. Ideally, nearly 100% of the light between the solar cells 136 be used.

The gap width of the cell columns 142 may for example be larger than in a conventional solar cell module. For example, the gap width may be in a range of about 3 mm to about 50 mm or even more, for example in a range of about 10 mm to about 50 mm.

In various embodiments, the bifacial photovoltaic module 100 Furthermore, a frame profiles 106 exhibit. The frame profiles 106 are at an angle to the module rear wall 124 arranged, for example, perpendicular or substantially perpendicular. In other words: the frame profiles 106 are raised with respect to the module rear wall 124 ,

The module back wall 124 is for example by means of the frame profiles 106 at a distance 128 to the laminate 138 arranged and with the laminate 138 connected. The distance 128 may be several cm, for example in a range of about 1 cm to about 10 cm.

The frame profiles 106 can have one or more terminals 102 . 104 exhibit to the laminate 138 to embrace and hold on its edge. The clamps 102 . 104 may be provided with a buffer material, for example soft rubber or a bond, to the laminate 138 not to damage.

In various embodiments, the module rear wall 124 several between the reflector struts and the cell columns 142 arranged spacers 122 on. In other words: the spacers 122 are like the reflector struts below the cell columns 142 arranged, and can therefore also be referred to as raised portions of the reflector struts.

The several spacers 122 are in contact with the back, for example 150 of the laminate 138 , The in contact with the back 150 surface of the spacers 122 is just. In other words: the spacers 122 are with respect to the reflector struts raised structures that extend along the distance 128 between the reflector struts and the laminate 138 extend.

The spacers 122 can be light-reflecting and perform a supporting and / or connecting task, such as the reflector struts in the distance 128 from the laminate 138 arrange, attach firmly, or the like.

For example, at least part of the plurality of spacers 122 adherent with the back 150 of the laminate 138 connected.

The reflector struts are thus outside the laminate 138 arranged. The reflector struts 124 may be striated or latticed below the cell columns 142 be formed and between adjacent support structures 122 be arranged (see also 3 ).

By means of the spacers 122 are clearly cavities 126 between the solar cell module 138 and the plane of reflector struts 124 whose height (ie distance from the bottom of the laminate 138 up to the top of the reflector struts 124 ) in a range of about 0.5 cm to 20 cm, for example in a range of about 1 cm to 10 cm, for example about 3 cm.

In various embodiments, the module rear wall 124 adherent with at least one outer edge and / or the back 150 of the laminate 138 connected.

An adherent connection or an adhesive connection is for example a cohesive connection, for example an adhesive connection, for example with a silicone as a connecting means. Alternatively or additionally, a firmly adhering connection is a frictional connection, for example a screwed or riveted connection or a clamping connection, for example by means of the clamps 102 . 104 ,

In various embodiments, the reflector struts 124 and the spacers 122 be formed in one piece or have a common piece. For example, the reflector struts 124 In addition, a reflective coating on the common piece of the reflector struts 124 and the spacer 122 exhibit.

For example, the module rear wall 124 by means of the spacers 122 adhesively bonded to the back of the laminate, for example by means of an adhesive bond, for example with silicone as a bonding agent.

The solar cells 136 can bifacial solar cells 136 be, for example, completely bifacial solar cells 136 or partially bifacial solar cells 136 , In the case that the solar cells 136 partially bifacial solar cells 136 are, the solar cells can 136 as so-called PERC solar cells 136 (PERC: Passivated Emitter Rear Cell), ie as solar cells 136 whose back is passivated.

The solar cells 136 have a photovoltaic layer which, according to various embodiments, has a base region and an emitter region. The base region is doped, for example, with dopant of a first doping type (also referred to as a first conductivity type), for example with dopant of the p-type doping, for example with dopant III. Main group of the periodic table, for example with boron (B). The emitter region is doped, for example, with dopant of a second doping type (also referred to as second conductivity type), the second doping type being opposite to the first doping type, for example with n-doping type dopant, for example with dopant of main group V of the Periodic Table, for example with phosphorus ( P).

In various embodiments, a selective emitter may optionally be formed in the emitter region. Furthermore, on the front 160 the solar cell 136 electrically conductive current collecting structures (for example, a metallization such as a silver metallization, which may be formed by burning a silver paste (the silver paste may be formed of silver particles, glass frit particles and organic auxiliaries)) such as so-called contact fingers and / or so-called busbars (not shown).

In various embodiments, an antireflection layer (for example comprising or consisting of silicon nitride) may optionally be applied to the exposed upper surface of the emitter region.

Furthermore, a plurality of metallic solder pads (not shown) may be provided, wherein each solder pad is electrically conductively connected to the emitter region, for example by means of a current collecting structure.

In various embodiments, the regions of increased dopant concentration may be doped with a suitable dopant, such as phosphorus. In various embodiments, the second conductivity type may be a p-type conductivity, and the first conductivity type may be an n-type conductivity. Alternatively, in various embodiments, the second conductivity type may be an n-type conductivity, and the first conductivity type may be a p-type conductivity.

For ease of explanation, the individual elements are on the front 160 the solar cell 136 are provided, not shown in the figures.

Furthermore, the solar cell 136 on her back 150 a dielectric layer structure (also referred to as Passivierungsstruktur) on. The dielectric layer structure has, for example, a double layer of thermal oxide and silicon nitride. However, alternative layer structures are also readily possible for the dielectric layer structure. For example, an arbitrary layer stack may be provided with layers having one or more of the compounds silicon nitride, silicon oxide or aluminum oxide in the dielectric layer structure.

• – einen im Wesentlichen ganzflächigen ersten Teilbereich, der im Wesentlichen im Mittenbereich des Substrates auf der dielektrischen Schichtenstruktur angeordnet ist und mittels Kontaktlöchern (auch bezeichnet als Kontaktöffnungen, beispielsweise lokale Kontaktöffnungen (LCO, local contact openings)), welche sich durch die dielektrische Schichtenstruktur hindurch erstrecken, mit dem Substrat, beispielsweise mit dem Basisbereich des Substrates, elektrisch leitend verbunden ist (in diesem Zusammenhang ist darauf hinzuweisen, dass in verschiedenen Ausführungsbeispielen auch eine Metallisierungspaste verwendet werden kann, die eingerichtet ist, die Nitridschicht zu durchbrechen (so genannte durchfeuernde Metallisierungspaste). Damit kann auch ohne Laseröffnung ein Kontakt durch die dielektrische Schichtenstruktur hindurch hergestellt werden); sowie
• – einen zweiten Teilbereich, der im Wesentlichen im Randbereich des Substrates auf der dielektrischen Schichtenstruktur angeordnet ist;
• – der zweite Teilbereich wird beispielsweise von Stromsammelstrukturen, die den Stromsammelstrukturen auf der Vorderseite 160 des Substrates ähnlich sind, gebildet;
• – beispielsweise können in dem zweiten Teilbereich elektrisch leitfähige Kontaktfinger (beispielsweise aus demselben Material, beispielsweise aus demselben Metall, wie der erste Teilbereich, beispielsweise aus Aluminium, oder aus einem anderen Material, beispielsweise einem anderen Metall) vorgesehen sein;
• – die Form der Stromsammelstrukturen ist grundsätzlich beliebig;
• – die Stromsammelstrukturen sind zumindest teilweise elektrisch leitend mit dem ersten Teilbereich und/oder (ebenfalls beispielsweise mittels Kontaktlöchern mit dem Substrat, beispielsweise mit dem Basisbereich des Substrates, verbunden.

Metallization is provided on the opposite side of the dielectric layer structure from the substrate. The metallization thus has, in various embodiments, essentially two subregions, namely

• A substantially full-area first partial area, which is arranged substantially in the middle region of the substrate on the dielectric layer structure and by means of contact holes (also referred to as contact openings, for example local contact openings (LCO)) which extend through the dielectric layer structure , is electrically conductively connected to the substrate, for example to the base region of the substrate (in this context, it should be noted that in various embodiments, a metallization paste can be used which is adapted to break through the nitride layer (so-called firing metallization paste). Thus, even without laser opening, contact can be made through the dielectric layer structure); such as
• A second subregion, which is arranged substantially in the edge region of the substrate on the dielectric layer structure;
• For example, the second subregion is made up of current collecting structures that correspond to the current collecting structures on the front side 160 of the substrate are formed;
• For example, electrically conductive contact fingers (for example of the same material, for example of the same metal, such as the first subregion, for example of aluminum, or of another material, for example a different metal) may be provided in the second subregion;
• - The form of the current collecting structures is basically arbitrary;
• - The current collection structures are at least partially electrically conductive with the first portion and / or (also, for example, by means of contact holes with the substrate, for example, connected to the base region of the substrate.

The shape and coupling of the individual elements of the current collecting structures may be arbitrary, for example contact fingers and / or at least one metal grid and / or metallic honeycombs and / or other openings in the metal surface (with any desired surface cross section) may be provided as described above.

Furthermore, a plurality of metallic solder pads may be provided, wherein each metallic solder pad is electrically connected to the metallization.

The solar cells 136 each have a substrate. The substrate may include or consist of at least one photovoltaic layer. Alternatively, at least one photovoltaic layer may be arranged on or above the substrate. The photovoltaic layer may include or consist of semiconductor material (such as silicon) or a compound semiconductor material (such as a III-V compound semiconductor material (such as GaAs).) In various embodiments, the silicon may comprise or consist of single crystal silicon, polycrystalline silicon, amorphous silicon, and / or microcrystalline silicon In various embodiments, the photovoltaic layer may include or consist of a semiconductor junction structure such as a pn junction structure, a pin junction structure, a Schottky-type junction structure, and the like. can be provided with a basic doping of a first conductivity type.

In various exemplary embodiments, the basic doping in the substrate may have a doping concentration (for example a doping of the first conductivity type, for example a p-doping, for example doping with boron (B)) in a range from approximately 10 ¹³ cm ^-3 to 10 ¹⁸ cm ^-3 , for example in a range of about 10 ¹⁴ cm ^-3 to 10 ¹⁷ cm ^-3 , for example in a range of about 10 ¹⁵ cm ^-3 to 2 x 10 ¹⁶ cm ^-3 .

In other words, the front 160 the solar cells 136 is the light incident side. With others: the front 160 is the light source and the incident light 140 facing. The substrate of the solar cells may have a front side contact structure on or on the front side. In addition, the emitter layer or the emitter region, for example a main doping region, for example an area with a high dopant concentration, is arranged on the front side. The backside 150 lies the front 160 across from. In other words: the back 150 is the side away from the light source and the incoming light. The backside 150 has a backside contact structure. In other words: on the back 150 of the substrate, a backside contact structure is formed or provided.

Moreover, at the back 214 arranged the back surface field (BSF). On the back of the reflected or reflected light (albedo) can occur.

Even if the solar cell 136 a PERC solar cell 136 However, the embodiments are not on such a PERC solar cell 136 limited. The described semi-bifacial solar cell 136 can be of any type of solar cell 136 be, only with each adapted backside metallization.

For example, is the back of the substrate of a solar cell 136 not fully passivated as with a PERC solar cell, so may additionally in the edge region in which the rear side of the base region is partially exposed, these are additionally covered with a passivation layer and the second subregion of the current collecting structure can then be arranged on the passivation layer. The passivation layer may include or may be silicon nitride. The passivation layer may include one or more dielectric layers.

2A and 2 B show schematic views of a bifacial photovoltaic module 200 according to various embodiments. The photovoltaic module according to 2A . 2 B is similar to the photovoltaic module according to 1 Therefore, to avoid repetition of the description of the characteristics of the photovoltaic module according to 1 which is also for the aspects of the photovoltaic module according to 3 to 5 applies except for the differences explained below.

In 2A are the reflector struts described above 230 the module rear wall 124 , which means the reflector struts 230 limited openings 220 and the frame profiles 106 illustrated. In addition, from the schematic view in 2A you can see that the frame profiles 106 are formed raised with respect to the module rear wall 124 , In other words: the frame profiles 106 may be formed as raised side walls of the module rear wall.

The frame profiles 106 and the module back wall 124 can be formed from one piece, ie, different, physically connected sections of a workpiece. In other words: the frame profiles 106 can as a raised, formed for receiving the laminate edge of the module rear wall 124 be educated.

Alternatively, the frame profiles 106 and the module back wall 124 separate and interconnected pieces. For example, the module back wall 124 have an area between the laminate 138 and the frame profiles 106 is arranged, for example, is adhesively bonded, for example by means of a clamping or adhesive connection.

In various embodiments, the frame profiles 106 and / or the module back wall 124 made of plastic, for example, a glass fiber reinforced plastic or a polyethylene; for example by means of injection molding, as a foam or foil. Alternatively, the frame profiles 106 and / or the module back wall 124 formed of sheet metal, for example of galvanized steel, aluminum or stainless steel; for example by means of deep drawing and stamping and / or welding. Alternatively or additionally, the opening in the module rear wall by means of a laser or a punch in a sheet, a plate or a film can be formed.

The frame profiles 106 and the module back wall 124 can be electrically non-conductive, for example in the form of a plastic frame.

In 2A is the back of the photovoltaic module 200 with several solar cells 136 shown above the module back wall 124 and the frame profiles 106 are arranged. Furthermore, a holding structure 250 of the photovoltaic module 200 for fixing the photovoltaic module 200 shown on a photovoltaic module external bracket.

over every opening 220 is at least one solar cell 136 or below at least one solar cell 136 is at least one opening 220 provided and in 2A seen. Furthermore, in 2 B you can see that the solar cells 136 in various embodiments may be arranged in multiple rows and columns, and the cell columns 142 or reflector struts 230 below the cell columns can also form multiple rows and columns and thus the cell columns 142 or the reflector struts 230 can form several intersection points. At the crossing points are several, in 2 B For example, four solar cells 136 , directly adjacent to each other or adjacent.

3 shows a view of a portion of a bifacial photovoltaic module according to various embodiments. In particular, in 3 a detail of a perspective view of the module rear wall and the frame profiles shown, wherein the reflective surface of the reflector struts 124 , the openings 220 which are arranged below the solar cells, and diamond-shaped spacers 122 as detailed in 4 be described. It can also be seen that the spacers 122 in various embodiments in several rows and columns below crossings of cell columns 142 can be arranged.

This in 3 not shown laminate can on the flat surface of the spacer 122 to be ordered.

The substrate of the solar cell 136 may be made of a solar cell wafer, and may have, for example, a round shape such as a circular shape or a polygonal shape such as a square shape. In various embodiments, the solar cells 136 However, the solar module also have a non-square shape. In these cases, the solar cells 136 of the solar module for example, by cutting (for example, cutting) and thus dividing one or more (in their form as a standard solar cell 136 Solar cell (s) to several non-square, square to the square (pseudo-square) or square solar cells 136 be formed.

In various configurations, the in contact with the back 150 surface shape of the spacers 122 be adapted to the surface shape of the crossing points. For example, the spacers 122 be designed as reflectors with a diamond shape or diamond shape. For example, in the case of pseudo-square solar cells with the corners removed in a diagonal cut, four directly adjacent solar cells may have a diamond-shaped cell gap 142 form. In this respect, a spacer with a diamond or diamond-shaped surface shape of the contact surface with the back of the laminate is adapted to the surface shape of the intersections of a laminate with pseudo-square solar cells.

The in contact with the back 150 surface shape of the spacers 122 For example, it may be adapted to the surface shape of the points of intersection such that the surface shape has the same or essentially the same shape and dimensions as the surface shape of the point of intersection, ie the same or essentially the same area and the same or essentially the same shape.

4 12 shows schematic cross-sectional views of reflector struts of a bifacial photovoltaic module according to various embodiments.

In various embodiments, the reflector struts 400 . 410 . 420 . 430 one of the back 150 facing, diffusely reflecting surface 440 on. Alternatively, the surface 440 formed reflective reflective.

For example, the reflector struts have an albedo of at least 50%, for example at least 90%.

For example, the laminate 138 facing surface of the reflector struts 230 White.

In various embodiments, at least part of the reflector struts 400 formed such that they have a trapezoidal cross-section. Alternatively or additionally, at least part of the reflector struts 410 formed so that they have a square or rectangular cross-section. Alternatively or additionally, at least part of the reflector struts 400 formed such that they have a trapezoidal cross-section. In other words, the reflector struts 400 . 410 can be a substantially straight and / or flat surface 440 exhibit.

Alternatively or additionally, at least part of the reflector struts 420 formed to have a tapered rounded, spherical or convex reflective surface 440 exhibit. Alternatively or additionally, at least part of the reflector struts 430 formed so that it has a rounded or concave reflective surface 440 exhibit. In other words, the reflector struts 420 . 430 can have a substantially rounded and / or curved surface 440 exhibit.

In various embodiments, the reflector struts 230 a width substantially equal to, equal to, or greater than the nip width of the cell column.

In various embodiments, the reflector struts 230 a length substantially equal to, equal to, or smaller than the length of the solar cells.

The distance 128 between the reflector struts and the laminate is measured as the distance from the reflective in the direction of the laminate top of the reflector struts to the back of the laminate. The thickness of the reflector struts may be dependent on the material and method of which they are made, so that the reflector struts are stable with respect to the mechanical stresses of the photovoltaic module during operation.

For example, have the reflector struts 230 between two crossing points a width in a range of about 2 mm to about 50 mm and a height in a range of about 2 mm to about 50 mm. The length of the reflector struts between two crossing points results from the side length of the solar cells, for example 157 mm.

The reflector struts 230 are formed, for example, from a metal sheet or a metal layer coated with a plate, such as a plastic plate. The metal of the reflector struts 124 may be a dull metal or a mirrored embossed metal, which may, for example, have small dents of the order of a few mm in diameter. Furthermore, the reflector struts 124 instead of metal, also have or be formed from a plate coated with a white ceramic pressure or a white plastic structure. Generally, in this context any diffuse reflective material for the reflector struts 124 or as a coating of the reflector struts 124 be used, for example, as at least partial coating, for example, at least laterally below the cell columns 142 ,

5 shows a bifacial photovoltaic module with multiple bifacial photovoltaic modules according to various embodiments.

In various embodiments, the frame profiles 106 at least one on an outer edge of the frame profiles 106 trained assembly structure 510 . 520 for fixing the photovoltaic module. The mounting structure 510 . 520 For example, has a Klemmfalz or more openings, such as holes / slots for mounting on. The mounting structure 510 . 520 For example, it is formed as a pin, flange or a flange portion, each of which may have a Klemmfalz or more holes for mounting.

Alternatively, the mounting structure 510 . 520 on the frame profiles 106 be attached, for example, be molded, for example, adherent to it.

A mounting structure 510 . 520 can be arranged on the front and / or longitudinal side of the respective photovoltaic module. A mounting structure 510 . 520 can be arranged centric or eccentric to the photovoltaic module.

In various embodiments, the frame profiles 106 at least two mutually staggered mounting structures 510 . 520 on. In various embodiments, the bifacial photovoltaic module 500 several bifacial photovoltaic modules 100 . 200 . 300 according to an embodiment described above. The several bifacial photovoltaic modules 100 . 200 . 300 are by means of mounting structures 510 . 520 fastened together.

For example, the mounting structures 510 . 520 the bifacial photovoltaic modules 100 . 200 . 300 each arranged offset such that the plurality of bifacial photovoltaic modules 100 . 200 . 300 are arranged flat to each other, as in 5 is illustrated.

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

• DE 102004049160 B4 [0007]

Claims (20)

Bifacial photovoltaic module ( 100 . 200 . 300 ) comprising: a laminate ( 138 ) with several solar cells ( 136 ) with a photosensitive front side ( 160 ) and a photosensitive back ( 150 ), wherein the plurality of solar cells ( 136 ) in the laminate ( 138 ) are electrically coupled together and in an encapsulating material ( 132 ) and in each case between two solar cells ( 136 ) a translucent cell gap ( 142 ) is provided; wherein a first transparent cover ( 130 ) over the encapsulating material ( 132 ), which the front ( 160 ) of the plurality of solar cells ( 136 covered); and wherein a second transparent cover ( 134 ) over the encapsulating material ( 132 ), which the back ( 150 ) of the plurality of solar cells ( 136 ), and one on at least two side edges of the laminate ( 138 ) fixed module rear wall ( 124 ) with translucent openings ( 220 ), whereby the module rear wall ( 124 ) several below the cell columns ( 142 ) arranged reflector struts ( 230 ), the translucent openings ( 220 ) below the solar cells ( 136 ) limit. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to claim 1, further comprising: two or four frame profiles ( 106 ), by means of which the module rear wall ( 124 ) at a distance ( 128 ) to the laminate ( 138 ) and with the laminate ( 138 ) connected is. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to claim 1 or 2, wherein the module rear wall ( 124 ) adherent with at least one outer edge and / or the back ( 150 ) of the laminate ( 138 ) connected is. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 3, wherein the module rear wall ( 124 ) several between the reflector struts ( 230 ) and the cell columns ( 142 ) arranged spacers ( 122 ), wherein the plurality of spacers ( 122 ) in contact with the back ( 150 ) of the solar cell laminate ( 138 ) are; and being in contact with the back ( 150 ) surface of the spacers ( 122 ) is just. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to claim 4, wherein the solar cells ( 136 ) are arranged in several rows and columns; and wherein the plurality of spacers ( 122 ) below crossings of the cell columns ( 142 ) are arranged. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to claim 5, wherein the in contact with the back ( 150 ) surface shape of the spacers ( 122 ) is adapted to the surface shape of the crossing points. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 6, wherein the reflector struts ( 230 ) one of the back ( 150 ) facing, diffusely reflecting surface; the reflector struts ( 230 ) have an albedo of at least 50%, preferably at least 90%. Bifacial photovoltaic module according to one of claims 1 to 7, wherein the laminate ( 138 ) facing surface of the reflector struts ( 230 ) is white. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 8, wherein the reflector struts ( 230 ) are formed such that at least a portion of the light passing through at least one cell gap ( 142 ) of the plurality of cells ( 142 ), on the backsides ( 150 ) of the solar cells ( 136 ) is reflected. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 9, wherein the reflector struts ( 230 ) at a distance ( 128 ) from about 2 mm to about 50 mm from the back ( 150 ) of the laminate ( 138 ) are arranged. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 10, wherein the gap width of at least one cell column ( 142 ) s of the multiple cell columns ( 142 ) in a range is from about 2 mm to about 30 mm. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 4 to 11, wherein at least a part of the plurality of spacers ( 122 ) adherent to the back ( 150 ) of the laminate ( 138 ) connected is. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 1 to 12, wherein the laminate ( 138 ) on the back ( 150 ) has a glass cover. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 2 to 13, wherein the frame profiles ( 106 ) and the module rear wall ( 124 ) are formed in one piece. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 2 to 14, wherein at least two opposing frame profiles ( 106 ) Openings for improved air circulation between the module rear wall ( 124 ) and laminate. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 2 to 15, wherein the frame profiles ( 106 ) and / or the module rear wall ( 124 ) are made of plastic / is. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 2 to 16, wherein the frame profiles ( 106 ) and / or the module rear wall ( 124 ) are formed from sheet metal is / is. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to one of claims 2 to 17, wherein the frame profiles ( 106 ) or the module rear wall ( 124 ) at least on two opposite outer edges formed mounting structures ( 510 . 520 ) for fixing the photovoltaic module ( 100 . 200 . 300 ) exhibit. Bifacial photovoltaic module ( 100 . 200 . 300 ) comprising a plurality of bifacial photovoltaic modules ( 100 . 200 . 300 ) according to claim 18, wherein the mounting structures ( 510 . 520 ) have a Klemmfalz or openings for fastening, and wherein the plurality of bifacial photovoltaic modules ( 100 . 200 . 300 ) by means of the assembly structures ( 510 . 520 ) are fastened together. Bifacial photovoltaic module ( 100 . 200 . 300 ) according to claim 18 or 19, wherein two opposing frame profiles ( 106 ) mutually staggered mounting structures ( 510 . 520 ), wherein the mounting structures ( 510 . 520 ) of the bifacial photovoltaic modules ( 100 . 200 . 300 ) are each arranged offset in such a way that the plurality of bifacial photovoltaic modules ( 100 . 200 . 300 ) are arranged flat to each other.

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