wind turbine blades

Abstract

A wind turbine blade comprising an elongated blade body (7) extending from a root (8) to a tip (9) and having a trailing edge (11), wherein at least one beam-shaped reinforcement device (18) is integrated into the blade body (7) adjacent to the trailing edge (11) for reinforcing the region (12) of the trailing edge (11), the reinforcement device (18) extending partially over the length of the blade body (7), wherein the reinforcement device (18) is a precast carbon beam (19) comprising carbon fibers.

Description

Technical Field

[0001] The invention relates to a wind turbine blade comprising an elongated blade body extending from a root to a tip and having a trailing edge, whereby at least one beam-like reinforcement device is integrated into the blade body adjacent to the trailing edge for reinforcing the region of the trailing edge, the reinforcement device extending partially over the length of the blade body. Background Art

[0002] Modern wind turbines include several, typically three, wind turbine blades attached to a rotor. As is generally known, the blades interact with the wind to cause the rotor to rotate.

[0003] Each wind turbine blade comprises an elongated blade body with a root portion, which serves to attach the blade to the rotor hub. The blade body extends from the root to the tip. The cross-sectional shape of the elongated blade body varies significantly over its length. The cylindrical root section transforms into a flattened airfoil-shaped cross-section that tapers toward the tip. As is well known, flat blades have a leading edge and a trailing edge on opposite sides of the blade body. In particular, the cross-sectional shape of the blade body in the region of the trailing edge varies significantly over the length of the blade body.

[0004] Reinforcements are necessary at or within the blade body to provide the required stiffness, taking into account the loads acting on the blade. High stiffness is required in the edge region and in the trailing edge region, where, as mentioned above, the shape and thickness vary significantly. To reinforce the trailing edge region, one or more beam-like reinforcements in the form of glass fiber beams are integrated into the blade body. Each beam comprises a plurality of individual glass fiber connecting plies embedded in a matrix (e.g., resin). Given the required mechanical properties and stiffness, the design of these glass fiber reinforced beams is challenging, as beam thickness is constrained by the limited space near the trailing edge. Consequently, integration of the beam-like glass fiber reinforcements is difficult.

[0005] Another issue is that the thick trailing glass beam design results in an irregular trailing core shape that is long and slender, which increases the difficulty of manufacturing the trailing core. The trailing core is arranged adjacent to the glass beam, and because the shape of the glass beam is quite complex and varies along its length, the trailing core is also difficult to manufacture and shape.

[0006] Finally, the relatively thick glass beam reinforcement significantly increases the blade mass and mass moment, which in turn has an impact on the arrangement of other structural components, such as the shell and the root, and has serious implications for the blade load-bearing capacity and the design of the hub. Summary of the Invention

[0007] It is an object of the present invention to provide an improved wind turbine blade.

[0008] In order to solve this problem, an innovative wind turbine blade is characterized in that the reinforcement means is a pre-cast carbon beam comprising carbon fibers.

[0009] In this innovative wind turbine, the beam-like reinforcement is implemented as a precast carbon beam composed of carbon fibers. This carbon beam is precast or prefabricated and can therefore be easily arranged in the mold where the blade is manufactured, where it is individually positioned and melted. This carbon beam replaces the glass fiber beam reinforcements used in the prior art, which are built up layer by layer in the mold and ultimately impregnated. Consequently, this innovative blade no longer exhibits the drawbacks associated with in-mold integration of glass fiber layer beams.

[0010] The carbon beam comprises carbon fibers embedded in a casting agent, preferably a resin or resin matrix. Because the beam is precast, it can be precisely formed to the desired shape, taking into account the available space in the trailing edge area. Consequently, it can be precisely adjusted to a given geometry and designed to meet specific requirements, particularly with regard to the desired mechanical properties.

[0011] Furthermore, the carbon beam exhibits enhanced mechanical properties over comparable glass beams, allowing carbon beams including carbon fibers to be smaller in their design while providing better mechanical properties due to the strengthened or reinforced trailing edge region.

[0012] In case of a smaller design, the weight is also reduced, resulting in a reduction in the weight or mass of the blade, which ultimately makes it possible to modify the entire blade design, especially with regard to the root area and the like.

[0013] Several embodiments are provided regarding the final configuration of the carbon beam. According to a first embodiment, the carbon beam is constructed from a single pultruded carbon fiber profile, or from one or more stacks of two or more pultruded carbon fiber profiles cast in a matrix material. According to this embodiment, the carbon beam is constructed from one or more pultruded carbon fiber profiles, preferably two or more pultruded carbon fiber profiles stacked one on top of the other. The beam may include only one such stack, or it may include two or more stacks arranged side by side. Biaxial material (preferably carbon biaxial material) may be inserted between each two adjacent stacks of pultruded carbon fiber to enhance the transverse performance of the carbon beam. Each pultruded carbon fiber profile includes carbon fibers embedded in a matrix material (e.g., resin). Finally, the entire stack or stacks are embedded in a matrix material (e.g., resin) to secure the stacked profiles and ultimately construct the beam. The matrix material may be different from the resin used to secure the stacked profiles.

[0014] Because the beam is made from individually stacked pultruded carbon fiber profiles, the overall cross-sectional shape of the final carbon beam can be varied. Thus, the stack, and therefore the height and / or width of the carbon beam, varies over the length of the beam. For example, the final carbon beam can become thicker and wider from root to tip, which can be achieved by varying the number of stacked profiles and by using profiles of varying widths. This allows for simple design changes in the carbon beam and allows it to be adapted to a given space.

[0015] Preferably, the carbon beam has a rectangular cross section. The invention is not limited to such a rectangular cross section, and also depending on the given space and the integration of the carbon beam in the entire blade body shell, a trapezoidal, polygonal or partially circular cross section etc. may be advantageous.

[0016] For integrating carbon beams, which preferably have a rectangular cross-section or at least one rectangular edge region, e.g., preferably, an elongated core element with a wedge-shaped cross-section is arranged at least on one side of the carbon beam and extends at least partially over the length of the beam. If a rectangular carbon beam is used, corresponding wedge-shaped core elements are preferably arranged on both sides. These preferably extend over at least a portion of the carbon beam's length, preferably over the entire beam length, and allow for a softer transition from the carbon beam to the adjacent shell region, which is mechanically connected to the shell region by means of a fiber web and a corresponding impregnated matrix material, the shell being constructed from the impregnated matrix material.

[0017] Preferably, the carbon beam is positioned on one side, close to the outer layer or surface of the blade body. In this embodiment, while offering excellent mechanical properties, the thickness of the carbon beam is quite small. Therefore, the beam can be positioned laterally on the blade body, preferably on the suction side, although it is also possible to provide two carbon beams on both sides (i.e., pressure and suction sides). One or both carbon beams are positioned close to the trailing edge, but do not necessarily extend directly into the extreme edge region. As mentioned above, due to the very slenderness or thinness of the carbon beam, it can be easily integrated into the shell arrangement. This can be achieved by covering the carbon beam with a corresponding fiber web impregnated with a resin matrix, for example.

[0018] Since the carbon beam can be arranged only on one blade side close to the outer blade surface, it is preferably necessary to place a corresponding reinforcement beam on the other side. Here, a reinforced glass beam comprising glass fibers can be integrated, which is arranged opposite to the carbon beam at the opposite side close to the outer layer or surface of the blade body. The carbon beam is connected to the reinforced glass beam by means of a connecting plate embedded in the corresponding resin matrix, so that the two beams arranged on the opposite blade body side are firmly connected to the corresponding shell area and to each other, so that the trailing edge area is well reinforced. In an alternative, a second carbon beam can also be integrated close to the outer layer at the opposite side, which second carbon beam is arranged like the first carbon beam, and the two carbon beams are connected by means of a connecting plate embedded in the resin matrix. Here, a carbon beam to carbon beam connection is given.

[0019] To fill the remaining space in the trailing edge region extending directly to the edge, a foam core element extending toward the trailing edge is preferably, viewed in cross-section, at least partially sandwiched between the upper and lower shells of the blade body, and in particular, between the carbon beam and the glass beam. As mentioned, it is possible to integrate only one carbon beam into the upper or lower shell, or two carbon beams into the upper and lower shells, or one carbon beam and one glass beam into the upper and lower shells. However, the final beam arrangement is such that the remaining space in the trailing edge region is filled with a foam core element that extends along the trailing edge region to the tip and into the trailing edge. Thus, this foam core element is sandwiched between the outer and inner shells, which can be provided with corresponding beams.

[0020] Finally, preferably, another core element is connected to the wedge-shaped core element and / or the glass beam near the corresponding outer layer. Each upper and lower shell is constructed with a corresponding additional core element, which is preferably connected to the integrated beam, whether carbon beam or glass beam. If the wedge-shaped core element is arranged near the carbon beam, the additional core element is connected to the wedge-shaped core element. The connection is also achieved by means of a fiber connecting sheet layer covering the connection area and impregnated with a corresponding resin matrix.

[0021] The carbon beam previously described in the first embodiment is made from several pultruded carbon fiber profiles. In an alternative, the carbon beam can be made from several pultruded carbon fiber rods or carbon fiber rovings cast in a matrix material. According to this embodiment, rather than using individual carbon fiber profiles, preferably rectangular ones, pultruded carbon fiber rods, for example, having a circular or oval shape, are used. The pultruded carbon fiber rods are arranged side by side and above and below each other, as needed and as the space available. When the pultruded carbon fiber rods are arranged in a multi-rod arrangement, the shape of the pultruded carbon fiber rods can also be adjusted or changed in a manner such that, when ultimately embedded in the precast matrix material, they can be deformed to a certain extent and the resulting carbon beam can be formed integrally. This arrangement thus allows for alternative configurations of the carbon beam and, in particular, allows the carbon beam to be formed to have a cross-section corresponding to the space defined by the outer layer, the trailing edge, and the shell, as will be described later.

[0022] As an alternative to using carbon fiber rods, carbon fiber rovings can also be used, which are precast in a matrix material. These rovings can be used in the form of strands or in the form of webs that can be stacked on top of each other to create a web stack. The shape of the web stack can also be adjusted due to the available space. The rovings are then impregnated with the matrix material.

[0023] The carbon beam of this second embodiment exhibits the same positive aspects and features as the carbon beam according to the first embodiment. It can also be formed into a thin, plate-like carbon beam as in the first embodiment, or it can be adjusted to a given space in the trailing edge region so as to be shaped in a certain manner to fill it, as will be described in detail below.

[0024] A carbon beam made of fiber rovings cast in a matrix material can consist solely of carbon fiber rovings. Alternatively, it is also possible for the carbon beam to consist of mixed carbon / glass fiber rovings. If the rovings are used in the form of a web, a stack can be constructed that, when the entire stack is ultimately impregnated in a resin material, is a mixed stack of carbon fibers and glass fibers.

[0025] Preferably, the carbon beam extends toward the trailing edge and is positioned adjacent to the surface of at least one outer layer and the blade body, respectively. In addition to the first alternative, the carbon beam, regardless of its configuration in the second embodiment, extends directly into the trailing edge, correspondingly extending into its end near the trailing edge. It is positioned adjacent to or attached to at least one side of the blade body, shell, or outer layer, but it may also preferably extend to the opposite side of the blade body, with a cross-section corresponding to the space defined by the outer layer, upper and lower shells, and the trailing edge, respectively. According to this embodiment, the cross-section of the carbon beam, made from pultruded carbon fiber rods or rovings or fiber webs impregnated with a corresponding matrix material, corresponds to a given space in the trailing edge region or directly at the trailing edge. This allows the space to be filled with a carbon beam having enhanced mechanical properties, thereby directly reinforcing the trailing edge itself. The remaining small space, particularly the space between the carbon beam and the final edge, can be filled with glass fiber webs and matrix material, using only a minimal amount of web and resin to fill the space, as the majority of the space is filled by the innovative carbon beam.

[0026] Furthermore, a foam core element can be placed adjacent to the carbon beam, extending further into the blade body and between the outer layers and the two shells. This foam core element further fills and reinforces the space in the trailing edge region. The foam core element is connected to additional shell core elements, which are placed in the two outer layers and in the upper and lower shells, respectively, to provide reinforcement.

[0027] In addition to a wind turbine blade, the invention also relates to a wind turbine having a rotor comprising several wind turbine blades as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings. However, the accompanying drawings are only schematic diagrams and are designed only for illustrative purposes and are not intended to limit the present invention. The accompanying drawings show:

[0029] Figure 1 shows a schematic diagram of an innovative wind turbine comprising three innovative wind turbine blades,

[0030] Figure 2 shows a partial cross-sectional view of a wind turbine blade in the region of a trailing edge of a first embodiment of a wind turbine blade,

[0031] Figure 3 showing a partial cross-sectional view of a wind turbine blade in the region of a trailing edge of a second embodiment of a wind turbine blade, and

[0032] Figure 4 is a cross-sectional view of another embodiment of a carbon beam. DETAILED DESCRIPTION

[0033] Figure 1 A schematic diagram of an innovative wind turbine 1 is shown, comprising a tower 2 having a nacelle 3 attached to the top of the tower, and a rotor 4 having a hub 5 to which are attached three wind turbine blades 6. Each wind turbine blade comprises a longitudinal blade body 7 having a root 8 and a tip 9 at the end of the blade body, the blade being attached to the hub via the root 8. Each blade 6 also has, on the other side, a leading edge 10 and a trailing edge 11, as viewed in the direction of rotation. The respective trailing edge region of each blade 6 is specially designed according to the present invention, as will be described in more detail below.

[0034] Figure 2 A first embodiment of an innovative wind turbine blade 6 is shown as a partial cross-section of a trailing edge region 12 extending into a trailing edge 11. The blade body 7 comprises a first or upper shell 13 and a second or lower shell 14. The first or upper shell 13 comprises an outer layer 15 or a stack of layers, while the second or lower shell 17 comprises an outer layer 16 or a stack of layers, which consists of one or preferably several fiber webs that are ultimately impregnated in a resin matrix.

[0035] Due to this shell construction, the interior 17 of the blade body 7 is hollow, making it necessary to reinforce the shell structure. Problems arise particularly in the trailing edge region 12, which varies significantly in cross section as viewed from root to tip.

[0036] According to the present invention, at least one reinforcement device 18 is integrated into the shell structure, here into the second or lower shell 14. This reinforcement device 18 takes the form of a precast or prefabricated carbon beam 19 comprising carbon fibers. In this embodiment, the carbon beam 19 is made from a stack of three individual pultruded carbon fiber profiles 20, stacked one on top of the other with biaxial carbon layers (not shown) between the profiles. The three individual pultruded carbon fiber profiles 20 are precast in a matrix material, typically a resin, that secures the individual profiles to the single carbon beam. The matrix material 30 is shown as an encapsulating material, but it also impregnates the stack between the respective profiles, which may be separated by interlayer glass fiber webs to allow for impregnation of the interlayer areas.

[0037] like Figure 2As shown, the carbon beam has a rectangular cross-section because all of the pultruded carbon fiber profiles 20 have rectangular cross-sections. Obviously, by varying the width of the individual carbon fiber profiles 20, the overall width of the stack or carbon beam 19 can be varied. Furthermore, simply by using pultruded carbon fiber profiles 20 with varying widths, the cross-sectional shape can be changed from, for example, a rectangular shape to a trapezoidal shape, etc. Finally, obviously, by varying the number of stacked carbon fiber profiles 20, the height of the stack, and thus the height of the resulting carbon beam 19, can also be varied.

[0038] A carbon beam 19 is arranged at the second or lower shell 14, adjacent to the outer layer stack or layer 16. On either side of the carbon beam 19, elongated core elements 21 having a wedge-shaped cross-section are arranged to provide a smooth transition to the outer layer 16. These wedge-shaped core elements 21 may be made of wood such as balsa or foam material, among others.

[0039] Adjacent to the right wedge-shaped core element 21, another core element 22 is arranged, which also has a wedge-shaped edge section so that it fits smoothly with the core element 21. The core element 22 is also integrated into the shell 14 and strengthens it.

[0040] On the opposite side of the first or upper shell 13, another reinforcement means 23 in the form of a reinforced glass beam 24 is integrated into the shell 13 and adjacent to the outer layer 15. The glass beam 24 comprises a stack of individual glass fiber web plies embedded in a shell resin matrix and strengthens the first or upper shell 13.

[0041] The carbon beams 19 and the glass beams 23 are connected by a web 25 which acts as a side web closing the trailing edge region 12 relative to the hollow interior 17 of the blade body 7. The webs 25 are also embedded in the resin matrix material and are therefore firmly attached to the corresponding internal fiber webs 26, thus covering the core elements 20, 21 and the carbon beams 19 and the core element 27 arranged in the upper shell 13 and connected to the glass beams 24, respectively.

[0042] like Figure 2 As further shown, the remaining space between the upper and lower shells 13, 14 and the connecting plate 25 is filled with a foam element 28 which, viewed in cross section, extends towards the trailing edge 11 and is directly connected to the resin-impregnated shells 13, 14 and is partially sandwiched between the carbon beam 19 and the wedge-shaped core element 21 on one side and the glass beam 24 on the other side. This foam element 28 completely fills the remaining space and reinforces the immediate edge area.

[0043] The carbon beam 19 offers exceptional mechanical properties and allows for excellent reinforcement and strengthening of the trailing edge region 12. It allows replacing the massive fiberglass webs and fiber-embedded resins typically used to fill the trailing edge region and reinforcing the trailing edge region by constructing fiberglass beams extending along the trailing edge and the trailing edge region, respectively. Thus, by integrating the relatively small carbon beam 19, the mass of the blade can be significantly reduced. During blade manufacture, the carbon beam 19 is easy to handle, as it can be placed directly into the shell mold used to manufacture the shell. Furthermore, lightweight foam elements 28 can be used to fill the remaining portion of the space in the trailing edge region 12, which also contributes to a reduction in mass.

[0044] The carbon beam 19 extends at least partially over the length of the trailing edge 11, but it extends almost completely into the tip 9. Over its length, it may vary in width and / or height depending on the given space and the required reinforcement or mechanical stability and performance.

[0045] Figure 3 Another embodiment of an innovative wind turbine blade 6 is shown, again comprising a blade body 7 having a trailing edge 11 and a trailing edge region 12. It also comprises a first or upper shell 13 having an outer layer 15 and a second or lower shell 14 having an outer layer 16.

[0046] In this embodiment, reinforcement means 18 in the form of carbon beams 19 are also integrated in the trailing edge region 12, but in a manner similar to that of FIG. Figure 3 In contrast, the carbon beam 19 is here arranged very close to the trailing edge 11 and has a cross section which corresponds at least partially to a given cross section of the space between the upper and lower shells 13 , 14 .

[0047] Here, the carbon beam 19 comprises a plurality of pultruded carbon fiber rods 29 embedded in a matrix material 30, which is again preferably a resin. The carbon fibers extend longitudinally, for example, toward the tip 9 and are embedded in the matrix material. The carbon fiber rods 29 are soft in some way and can therefore be arranged in such a way that they can be deformed in some way so as to shape the entire cross-section of the carbon beam 19, as shown in FIG. Figure 3 In this final form or mould, the rods 29 are then impregnated or embedded in a matrix material 30 which is subsequently cured so that a stable but specially designed carbon beam 19 can be constructed.

[0048] The remaining space between the carbon beam 19 and the trailing edge 11 is filled with a fiber web 31 embedded in a resin matrix 32 , which also embeds the corresponding web layers constituting the upper shell 13 and the lower shell 14 .

[0049] A foam element 28 is arranged adjacent to the carbon beam 19, which also extends between the two shells 13, 14 and fills the remaining space in the trailing edge region 12 between the two shells 13, 14 and the connecting plate 25, which connects the core elements 22 and 27 here. The core elements 22 and 27 are arranged in the shells 13 and 14 and are covered by the corresponding connecting plates 26, while the entire arrangement in the trailing edge region 12 is finally impregnated with the shell matrix material.

[0050] Also in this embodiment, the carbon beam 19, including the pultruded rods 29, extends partially over the length of the trailing edge, but extends almost completely to the tip 9. Here too, it can of course vary in its width and height, since it is designed to fill as much as possible the space which varies significantly along its length to the tip 9.

[0051] Although Figure 3 A carbon fiber beam 19 is shown which is made of a plurality of individual pultruded carbon fiber rods 29 comprising the corresponding carbon fibers, but a carbon fiber beam 19 of comparable shape design can also be constructed by using carbon fiber rovings and embedding them in a matrix. Such a carbon beam 19 consisting of carbon fiber rovings 33 embedded in a matrix material 30 is Figure 4 , shown in cross-section in FIG. A hybrid beam can be constructed using only carbon fiber rovings, or using both carbon and glass fibers. The rovings extend along the longitudinal axis of the carbon beam 19 and thus along the trailing edge 11 to the tip. Finally, carbon fiber webs can also be used. Several fiber webs are stacked to form a web stack, which is then embedded in the matrix material. This web stack can consist solely of carbon fiber webs or layers, but it can also be a hybrid stack comprising several interlayer glass fiber webs or layers, which allow the entire stack to be better impregnated in its volume.

[0052] Although the present invention has been described in detail with reference to the preferred embodiments, the present invention is not limited to the disclosed examples, and those skilled in the art can derive other variations from the disclosed examples without departing from the scope of the present invention.

Claims

1. A wind turbine blade comprising an elongated blade body (7) extending from a root (8) to a tip (9) with a trailing edge (11), wherein: At least one beam-shaped reinforcement device (18) is integrated into the blade body (7) adjacent to the trailing edge (11) for reinforcing the region (12) of the trailing edge (11), the reinforcement device (18) extending partially over the length of the blade body (7), characterised in that the reinforcement device (18) is a precast first carbon beam (19) comprising carbon fibres.

2. The wind turbine blade according to claim 1, wherein: The first carbon beam (19) is made of a single pultruded carbon fiber profile, or a stack of two or more pultruded carbon fiber profiles (20), or several of the stacks arranged side by side and cast in a matrix material (30).

3. The wind turbine blade according to claim 2, wherein: A layer of biaxial material is arranged between two stacked pultruded carbon fiber profiles (20).

4. The wind turbine blade according to claim 2, wherein: The biaxial carbon layer is arranged between two stacked pultruded carbon fiber profiles (20).

5. The wind turbine blade according to any one of claims 2 to 4, characterized in that The height and / or width of the stack varies over the length of the first carbon beam (19).

6. A wind turbine blade according to any one of claims 2 to 4, characterized in that The first carbon beam (19) has a rectangular, trapezoidal, polygonal or partially circular cross section.

7. A wind turbine blade according to any one of claims 2 to 4, characterized in that An elongated core element (21) having a wedge-shaped cross-section is arranged at least at one side of the first carbon beam (19) and extends at least partially over the length of the first carbon beam (19).

8. The wind turbine blade according to claim 7, wherein: The first carbon beam (19) is arranged on one side, close to the first outer layer (16) of the blade body (7).

9. The wind turbine blade according to claim 8, wherein: The first carbon beam (19) is connected to a reinforced glass beam (24) including glass fibers or to a second carbon beam, the glass beam (24) or the second carbon beam being arranged at an opposite side relative to the first carbon beam (19) near a second outer layer (15) of the blade body (7) and connected to the first carbon beam (19) via a connecting plate (25).

10. A wind turbine blade according to any one of claims 2 to 4, characterized in that Viewed in cross-section, a foam core element (28) extending towards the trailing edge (11) is at least partially sandwiched between upper and lower shells (13, 14) of the blade body (7).

11. The wind turbine blade according to claim 9, wherein: Viewed in cross-section, a foam core element (28) extending towards the trailing edge (11) is at least partially sandwiched between the first carbon beam (19) and the glass beam (24).

12. The wind turbine blade according to claim 9, wherein: Further shell core elements (22, 27) are connected to the first carbon beam (19) or to the elongated core element (21) and / or to the glass beam (24) adjacent the respective first outer layer (16) and second outer layer (15).

13. The wind turbine blade of claim 1, wherein: The first carbon beam (19) is made of a plurality of pultruded carbon fiber rods (29) or carbon fiber rovings (33) cast in a matrix material (30).

14. The wind turbine blade according to claim 13, wherein: The first carbon beam (19) comprises only carbon fiber rovings or mixed carbon / glass fiber rovings (33).

15. A wind turbine blade according to claim 13 or 14, characterized in that The first carbon beam (19) extends toward the trailing edge (11) and is arranged adjacent to at least one of a first outer layer (16) and a second outer layer (15) of the blade body (7).

16. The wind turbine blade according to claim 15, wherein: The first carbon beam (19) extends to opposite sides of the blade body (7) and has a cross section corresponding to a space defined by upper and lower shells (13, 14) of the blade body (7) and the trailing edge (11).

17. The wind turbine blade according to claim 16, wherein: A foam core element (28) is arranged adjacent the first carbon beam (19), extends further into the blade body (7) and extends between the upper and lower shells (13, 14).

18. The wind turbine blade according to claim 17, wherein Further shell core elements (22, 27) are connected to the foam core element (28) adjacent both the first outer layer (16) and the second outer layer (15).

19. Wind turbine having a rotor (4) comprising several wind turbine blades (6) according to any one of the preceding claims.

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