Wind turbine blade component comprising nonwoven fabric

Abstract

The present invention relates to a wind turbine blade component comprising a laminate structure comprising a nonwoven fabric comprising a plurality of first fibers and a plurality of second fibers, where the plurality of first fibers are randomly oriented carbon fibers entangled with the plurality of second fibers, and where the plurality of second fibers are randomly oriented carbon fibers entangled with the plurality of second fibers. The plurality of second fibers are fibers of a different type than the carbon fibers.

Description

Technical Field

[0001] The present disclosure relates to a wind turbine blade component including a nonwoven fabric and a method for manufacturing such a wind turbine blade component. Background Art

[0002] Wind energy provides a clean and environmentally friendly energy source. Wind turbines generally include a tower, a generator, a gearbox, a nacelle, and one or more rotor blades. Wind turbine blades use the known airfoil principle to capture the kinetic energy of the wind. Modern wind turbines can have rotor blades with lengths exceeding 90 meters and even exceeding 100 meters.

[0003] Wind turbine blades are typically manufactured by forming two shell parts or shell halves from multiple layers of woven fabric or fibers and resin. Wind turbine blades include multiple wind turbine blade components such as spar caps. The spar caps are placed or integrally incorporated into the shell halves and can be combined with other wind turbine blade components (such as shear webs or spar booms) to form a structural support member. The spar caps can be connected to the inside of the suction and pressure halves of the shell or integrally incorporated into the inside of the suction and pressure halves of the shell.

[0004] Numerous studies have demonstrated the advantages of using advanced materials compared to conventional materials in the field of wind turbine blades. Using advanced materials includes using materials with certain desired properties, such as low weight to reduce gravity, high strength to withstand the wind and gravity forces on the blade, high fatigue resistance to withstand cyclic loads, and high stiffness to ensure the stability of the optimal shape.

[0005] However, there is a need to replace some of the advanced and / or conventional materials used in different wind turbine blade components with cheaper and more environmentally friendly materials without compromising the performance of the wind turbine blade components. Summary of the Invention

[0006] An object of the present disclosure is to provide a wind turbine blade component including cheaper and more environmentally friendly materials without compromising the performance of the wind turbine blade component. Another object of the present disclosure is to provide a method for manufacturing such a wind turbine blade component.

[0007] Accordingly, in a first aspect, the present disclosure relates to a wind turbine blade component including a laminated structure including a nonwoven fabric including a plurality of first fibers and a plurality of second fibers, wherein the plurality of first fibers are randomly oriented carbon fibers entangled with the plurality of second fibers, and the second fibers are fibers of a type different from carbon fibers.

[0008] An important aspect of the present invention is the fact that multiple first fibers and multiple second fibers are entangled. It should be understood that the multiple first fibers are also entangled with each other. In the same way, the multiple second fibers are also entangled with each other. This is because fiber entanglement confers several advantages to the non-woven fabric compared to other non-woven fabrics used in the wind turbine industry. The non-woven fabric comprising entangled fibers described herein should not be confused with a non-woven fabric simply comprising randomly arranged or mixed fibers, where the fibers are held together by some means (such as by an adhesive or by stitching). Entanglement is understood herein to result in an entanglement of the multiple first fibers and the multiple second fibers to such an extent that the non-woven fabric can be handled and transported without other means (such as an adhesive or stitching) to hold the fibers together. Thus, in a preferred embodiment, the multiple first fibers and the multiple second fibers in the non-woven fabric are not held together by an adhesive or by stitching.

[0009] The fact that no adhesive or stitching is required to produce the non-woven fabric is advantageous because it makes the manufacturing process of the non-woven fabric cheaper and simpler. Additionally, such non-woven fabrics have some advantageous properties caused by the entanglement of the fibers, such as good permeability attributable to the arrangement of the fibers. This is advantageous if the non-woven fabric is used in a wind turbine blade component, for example as a sandwich in a spar cap, where the permeability of the sandwich is very important for the proper bonding of pultruded parts in a laminated structure. Moreover, due to the use of carbon fibers, such fabrics have good electrical conductivity, which is particularly advantageous when used in wind turbine components such as spar caps because it reduces the risk of problems caused by lightning strikes. This is because wind turbine blade components such as spar caps typically include conductive fibers, such as carbon fibers. During a thunderstorm, if the fibers of different elements are not electrically connected, a voltage difference may occur between individual carbon elements, and there is a risk of damage or even fire in the wind turbine blade component. However, due to the presence of carbon fibers in the non-woven fabric of the present invention, the non-woven fabric is conductive and suitable for use as a sandwich in a laminated structure such as the spar cap of a wind turbine blade.

[0010] One method of entangling multiple first fibers and multiple second fibers to the extent of producing a nonwoven fabric without additional means to hold the fibers together is needle felting. Needle felting may also be referred to as the needle punching method. The general principle of this method is to layer a web or felt of fiber material on a surface and then pierce the fiber material with barbed needles. The barbs of the needles used for needle felting are also called notches and should not be confused with barbs in the form of protrusions (such as barbed wire), as such barbs are difficult to penetrate into the fibers and almost impossible to pull out. Felting needles are thin and sharp, and the needle shafts come in various different specifications and shapes. A needle felting machine includes multiple needles that have angled notches along the shaft, and the notches are configured to grab the fibers and entangle them together. When the needles pierce the fiber material, some of the fibers are captured by the needles and pressed against the surface. When the needles are pulled back, the barbs pull some of the fibers up away from the surface. This needling action causes the fibers to interlock and holds the structure together. By repeating this process, the fibers will become increasingly entangled until a nonwoven fabric that can be handled and transported is produced.

[0011] During the needle felting process, multiple fibers including multiple first fibers and multiple second fibers are entangled to form a complex and unique fiber network that has a sticky, fluffy, and non-uniform structure, and the structure includes multiple fibers protruding from the plane. Needle felt nonwoven fabrics are more drapable and more flexible than other fabrics. It has good elongation properties in the X and Y directions and can thus be more easily applied to complex shapes with curvature, such as spar cap molds. In addition, the fabric has good stability and handling ability.

[0012] Due to the fiber entanglement, the needle felt material preferably includes multiple interlocked fibers. Interlocked fibers mean the configuration of two fibers in a nonwoven fabric, where the movement of one of the two fibers in one direction causes at least a portion of the other fiber of the two fibers to move in the same direction. The interlocking of a large number of fibers constitutes the polymeric structure of the nonwoven fabric.

[0013] In addition, due to the fiber entanglement, the needle felt material preferably includes multiple fibers or multiple fiber portions having a U-shaped configuration. During the needle felting process, when horizontally arranged fibers are pierced by the needles through the fiber material, this U-shaped configuration can be produced. In addition, when the needles are pulled back from the fiber material, they pull some of the fibers up, which can produce an inverted U-shaped configuration. In some embodiments, the fibers having a U-shaped configuration extend from one larger surface of the nonwoven fabric to the opposite larger surface of the nonwoven fabric, i.e., in the thickness direction.

[0014] Therefore, in some embodiments, the entangled fibers include multiple interlocked fibers and / or multiple fibers or multiple fiber portions having a U-shaped configuration.

[0015] Needled felt nonwoven fabrics can be made by hand, but can be manufactured using special barbed felting needles on industrial felting machines.

[0016] The construction of needled felt nonwoven fabrics can start with large bales of loose fibrous material. These bales of fibers can then enter a machine called a bale opener. These machines can break up the tightly packed bales of fibers so that they are easier to process. Many felts involve mixing different types of fibers together in order to achieve a desired effect. This can be accomplished by carefully weighing the fibers that enter the next processing steps (intermixing and carding) from the bale opener to achieve the correct percentage of intermixing. The breakdown and mixing of the fibers can be done in carding. Carding can involve feeding a loose fiber bed into a large wire drum. The wire can separate each strand of fiber, mix and intermix the components together, and orient the fibers in a single direction. The fibers leave the carding machine in the form of a web. This is the first time the fibers look like a fabric, but like cotton candy, the material has very little strength on it. The web can be laid onto a conveyor belt that transports the web to a cross-lapper. The cross-lapper can fold each thin layer of the web, which provides weight and thickness to the finished felt. The number of layers depends on the target thickness and weight of the finished product. After the cross-lapper, the web layers can enter a knitting machine. Knitting machines are precision machines that use barbed needles mounted on a needle bed to pierce through the layered fiber web. The needle bed needles the fibers at a rate of 600 - 2000 needle penetrations per minute. This repeated piercing of the needles causes the fibers to tangle together, which creates a strong bond. The knitting machine can be "in-line" or "off-line". For some felts, this is the end of the felt-making process. But others are subject to different finishing treatments, such as additional needling or adding more felt layers to increase density, heat treatment, calendering, singeing, and laminating.

[0017] In a preferred embodiment, the nonwoven fabric is a needled felt nonwoven fabric. In other words, the nonwoven fabric is obtained by needled felting. Making a needled felt nonwoven fabric does not require water, air, heat, and chemicals because needled felting is a pure physical and mechanical bonding method. However, nonwoven fabrics can also be made by other methods as long as multiple first fibers and multiple second fibers are tangled to such an extent that the nonwoven fabric can be handled and transported without other means (such as adhesives or stitching) to hold the fibers together.

[0018] In some embodiments, there are additional manufacturing steps after the needled felting process, such as heat pressing with a heat belt, to further reinforce the nonwoven fabric so that it is smaller in volume when handled and laid. In some embodiments, a small amount of hot melt fibers are added to the nonwoven fabric to effectively glue the fibers in the compacted form of the nonwoven fabric produced by heat pressing with a heat belt.

[0019] In another aspect of the present invention, multiple fibers can be entangled by using an air jet or a water jet to press the multiple fibers together. Thus, in another aspect of the present invention, the present disclosure relates to a wind turbine blade member that includes a laminated structure, the laminated structure including a nonwoven fabric that includes multiple first fibers and multiple second fibers, wherein the multiple first fibers are randomly oriented carbon fibers that are entangled with the multiple second fibers, and wherein the multiple first fibers and the multiple second fibers are entangled by using an air jet or a water jet to press them together.

[0020] In some embodiments, the nonwoven fabric is reinforced by a stitching pattern. Importantly, such a stitching pattern is not necessary for holding the multiple fibers in the nonwoven fabric together, but is only used to reinforce the nonwoven fabric or impart desired flow characteristics to the fabric. In some embodiments, the stitching pattern is produced by a stitching thread that includes polyester fibers or consists essentially of polyester fibers. The stitching thread can also be another material, such as carbon fiber, but polyester fibers are the most common from a technical and commercial perspective. In some embodiments, the stitching pattern includes multiple stitching rows for stabilizing the fabric for handling purposes. In some embodiments, the multiple stitching rows are arranged along the longitudinal direction and / or the transverse direction of the nonwoven fabric. The stitching pattern can be a standard chain stitch or any other type of known stitching pattern.

[0021] In a preferred embodiment, the wind turbine blade member is a spar cap. The fact that the wind turbine blade is a laminated structure means that the wind turbine blade member is a layered structure, i.e., a structure that includes several layers of consolidated material. The spar cap is a laminated structure. In a preferred embodiment, the laminated structure is a spar cap. Thus, in some embodiments, the wind turbine blade member can be composed of a laminated structure, which can be a spar cap.

[0022] In some embodiments, the multiple fibers in the nonwoven fabric are further held together by an adhesive. Importantly, in such embodiments, the adhesive is not necessary for holding the multiple fibers in the nonwoven fabric together.

[0023] In another aspect of the present invention, multiple fibers are held together by an adhesive. Thus, in another aspect of the present invention, the present disclosure relates to a wind turbine blade member that includes a laminated structure, the laminated structure including a nonwoven fabric that includes multiple first fibers and multiple second fibers, wherein the multiple first fibers are randomly oriented carbon fibers, and the multiple second fibers are fibers of a type different from carbon fibers, and wherein the multiple first fibers and the multiple second fibers are held together by an adhesive.

[0024] In some embodiments, the laminated structure includes - A plurality of fiber reinforcement elements, including a first fiber reinforcement element and a second fiber reinforcement element; and - A substantial amount of nonwoven fabric, including a first nonwoven fabric embedded in a first cured resin and disposed between the first fiber reinforcement element and the second fiber reinforcement element.

[0025] In some embodiments, each of the plurality of fiber reinforcement elements includes a plurality of stacked fiber reinforcement layers. In some embodiments, the plurality of fiber reinforcement elements are pre-cured fiber reinforcement elements, such as pultruded profiles including carbon fiber and / or glass fiber. In some embodiments, the substantial amount of nonwoven fabric is an interlayer for facilitating resin infusion between the plurality of fiber reinforcement elements. In some embodiments, the first cured resin is an epoxy resin, a polyester resin, a polyurethane resin, or a vinyl ester resin.

[0026] In some embodiments, the nonwoven fabric (embedded in the first cured resin) has a thickness between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.5 mm, such as 0.35 mm. This is the thickness of the nonwoven fabric in the laminated structure, that is, the thickness after being embedded in the first cured resin. The thickness of the nonwoven fabric is greater than its thickness before being embedded in the resin and before becoming part of the laminated structure.

[0027] In some embodiments, the nonwoven fabric (embedded in the first cured resin) has an areal weight between 50 g / m 2 and 200 g / m 2 preferably between 70 g / m 2 and 150 g / m 2 such as 75 g / m 2 80 g / m 2 or 100 g / m 2 of the nonwoven fabric.

[0028] The degree of entanglement of the fibers in the nonwoven fabric is related to the density of the nonwoven fabric. The higher the material density, the higher the degree of entanglement. Therefore, a higher density of the nonwoven fabric can be achieved by repeating the felting process (by pushing barbs through the mesh layer, and the barbs catch the scales on the fibers, thus entangling them and bonding them together).

[0029] A plurality of first fibers are carbon fibers. In some embodiments, a plurality of second fibers are also carbon fibers, that is, the only fiber type in the nonwoven fabric is carbon fiber.

[0030] In some embodiments, each of the plurality of carbon fibers is covered in a sizing layer. The sizing layer is a very thin layer of chemical substance that improves the bonding between the plurality of carbon fibers in the nonwoven fabric and a fiber reinforcement layer (such as a pultruded carbon slat of a spar cap). However, the sizing layer has a slight insulating effect on the plurality of carbon fibers. It is known to those skilled in the art that carbon fibers used in laminated structures are typically covered by a sizing layer.

[0031] In a preferred embodiment, the plurality of carbon fibers are chopped carbon fibers. In a preferred embodiment, the nonwoven fabric includes carbon fibers that protrude out of the plane of the fabric. Protruding out of the plane means that the fiber or a portion of the fiber extends in a direction not parallel to the two largest surfaces of the nonwoven fabric. In some embodiments, some of the fibers protruding out of the plane include portions that extend perpendicular or substantially perpendicular to the plane (i.e., in the thickness direction of the nonwoven fabric). In a needle-punched nonwoven fabric, some of the fibers can extend from one side of the nonwoven fabric to the other side of the nonwoven fabric. Thus, if the fabric is sandwiched between two elements (such as two pultruded slats), the fibers will contact the two elements. Preferably, the carbon fibers protruding out of the plane of the nonwoven fabric are configured to contact a fiber reinforcement layer (such as a carbon pultruded slat of a spar cap). It is advantageous for the chopped carbon fibers to protrude out of the plane because the free ends of the chopped carbon fibers are not covered by the sizing layer. Thus, the free ends of the chopped carbon fibers facilitate the circuit path between the nonwoven fabric and the fiber reinforcement layer (such as a pultruded carbon slat of a spar cap). Thus, in a preferred embodiment, the nonwoven fabric includes chopped carbon fibers, and the ends of the chopped carbon fibers are not covered by the sizing layer, and the carbon fibers protrude out of the plane of the nonwoven fabric, preferably out of the upper surface and / or the lower surface of the nonwoven fabric.

[0032] In some embodiments, each of the plurality of carbon fibers has an average length between 1 mm and 10 mm, preferably between 3 mm and 7 mm, such as between 4 mm and 7 mm. In some embodiments, each of the plurality of carbon fibers has an average length between 10 mm and 100 mm, preferably between 30 mm and 70 mm, such as between 40 mm and 70 mm. In some embodiments, the plurality of carbon fibers are carbon fiber tows, such as chopped carbon fiber tows.

[0033] In a preferred embodiment, the plurality of carbon fibers are recycled or regenerated carbon fibers. The recycled carbon fibers can be recovered by cutting longer fibers into short carbon fibers having the average length mentioned above. The use of such recycled or regenerated carbon fibers is advantageous because it makes the wind turbine components more environmentally friendly. In addition, the wind turbine industry generates a large amount of carbon waste. Therefore, compared with wind turbine components made of other materials, the use of recycled or regenerated carbon fibers in the industry makes wind turbine components including nonwoven fabrics with recycled carbon fibers sustainable. Regenerated or recycled fibers cannot be easily used in any type of fabric. However, they are particularly easy to use for needled nonwoven fabrics.

[0034] In some embodiments, the first fibers are not carbon fibers, but another type of fiber, such as glass fibers and / or polymer fibers. Such embodiments may be preferred if the nonwoven fabric is arranged as a sandwich in a spar cap including a glass fiber pultrusion. In such embodiments, the electrical conductivity of the carbon fibers is not required. That being said, if the nonwoven fabric including carbon fibers is used as a sandwich between glass pultrusions in a spar cap, it still has advantages in terms of cost and fracture toughness regardless of the electrical conductivity.

[0035] In some embodiments, the plurality of second fibers are monofilaments. The average diameter of the monofilaments can be, for example, between 100 μm and 1000 μm, preferably between 150 μm and 500 μm, such as about 250 μm or 350 μm.

[0036] In a preferred embodiment, the plurality of second fibers are polymer fibers, preferably polyester fibers.

[0037] In some embodiments, the plurality of polyester fibers have a diameter between 20 μm and 60 μm, such as between 30 μm and 60 μm, such as between 40 μm and 60 μm, such as between 50 μm and 60 μm. In some embodiments, the plurality of polyester fibers have a diameter between 20 μm and 50 μm, such as between 20 μm and 50 μm, such as between 30 μm and 50 μm, such as between 40 μm and 50 μm. In some embodiments, the plurality of polyester fibers have a diameter between 35 μm and 60 μm, such as between 35 μm and 55 μm, such as between 35 μm and 50 μm, such as between 35 μm and 45 μm, such as 40 μm.

[0038] In some embodiments, the plurality of polyester fibers have an average length between 20 and 100 mm, such as between 20 and 90 mm, such as between 20 and 80 mm, such as between 20 and 70 mm, such as between 20 and 60 mm, such as between 20 and 50 mm, such as between 20 and 40 mm, such as between 20 and 30 mm, such as between 30 and 100 mm, such as between 30 and 90 mm, such as between 30 and 80 mm, such as between 30 and 70 mm, such as between 30 and 60 mm, such as between 30 and 50 mm, such as between 30 and 40 mm. In some embodiments, the plurality of polyester fibers have an average length between 2 and 10 mm, such as between 2 and 9 mm, such as between 2 and 8 mm, such as between 2 and 7 mm, such as between 2 and 6 mm, such as between 2 and 5 mm, such as between 2 and 4 mm, such as between 2 and 3 mm, such as between 3 and 10 mm, such as between 3 and 9 mm, such as between 3 and 8 mm, such as between 3 and 7 mm, such as between 3 and 6 mm, such as between 3 and 5 mm, such as between 3 and 4 mm.

[0039] In some embodiments, the plurality of carbon fibers are carbon fiber tows, such as chopped carbon fiber tows, and the second plurality of fibers are monofilaments. It has been found that the combination of monofilaments and carbon fiber tows provides a good balance between the requirements of flow characteristics and electrical conductivity.

[0040] In some embodiments, the ratio between the plurality of carbon fibers and the plurality of second fibers in the nonwoven fabric is between 3:1 and 1:0, such as between 19:1 and 1:0, that is, the amount of carbon fibers in the nonwoven fabric is between 75% and 100%, such as between 95% and 100%. In some embodiments, the ratio between the plurality of carbon fibers and the plurality of second fibers in the nonwoven fabric is between 1:3 and 3:1, such as between 1:2 and 2:1. It has been found that such ratios can provide an optimal balance between achieving the desired flow characteristics and the characteristics regarding electrical conductivity. In some embodiments, the ratio in volume % between the plurality of carbon fibers and the plurality of second fibers in the nonwoven fabric is between 1:3 and 3:1, such as between 1:2 and 2:1. In some embodiments, the ratio in weight % between the plurality of carbon fibers and the plurality of second fibers in the nonwoven fabric is between 1:3 and 3:1, such as between 1:2 and 2:1.

[0041] In some embodiments, the nonwoven fabric further comprises a plurality of third fibers of a fiber type different from carbon fibers and polyester fibers. However, in some embodiments, the nonwoven fabric contains only two types of fibers.

[0042] Preferably, a nonwoven fabric including a plurality of first fibers entangled with a plurality of second fibers is produced as a fiber mat, which can be rolled up for storage and unrolled for use.

[0043] In a second aspect, the present invention relates to a method of manufacturing a wind turbine blade component, such as a spar cap, according to the first aspect of the present invention, wherein the method comprises the steps of: - providing a plurality of fiber reinforcement elements, which include a first fiber reinforcement element and a second fiber reinforcement element; - providing a plurality of nonwoven fabrics, which include a first nonwoven fabric including a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are randomly oriented carbon fibers entangled with the second plurality of fibers, and the second plurality of fibers are fibers of a type different from carbon fibers; - arranging the first nonwoven fabric between the first fiber reinforcement element and the second fiber reinforcement element such that the fiber reinforcement elements are separated by the first nonwoven fabric; - infusing a first resin between the plurality of fiber reinforcement elements and the plurality of nonwoven fabrics; - curing the resin to form a wind turbine blade component.

[0044] In some embodiments, the step of providing the first nonwoven fabric according to the first aspect of the present invention comprises the steps of: - providing a plurality of webs or felts including a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are carbon fibers, and the second plurality of fibers are fibers of a type different from carbon fibers, and - needling and felting the first plurality of fibers and the second plurality of fibers to entangle the fibers until a predetermined areal weight is obtained.

[0045] In a preferred embodiment, the wind turbine blade component is a spar cap.

[0046] In some embodiments, each of the plurality of fiber reinforcement elements includes a plurality of stacked fiber reinforcement layers. In some embodiments, the plurality of fiber reinforcement elements are pre-cured fiber reinforcement elements, such as pultruded elements (also known as pultrusions) including carbon fibers and / or glass fibers. In some embodiments, the plurality of nonwoven fabrics are interlayers for facilitating resin infusion between the plurality of fiber reinforcement elements. In some embodiments, the first cured resin is an epoxy resin, a polyester resin, a polyurethane resin, or a vinyl ester resin.

[0047] In some embodiments, the plurality of first fibers, i.e., carbon fibers, are recycled carbon fibers, and the step of providing recycled carbon fibers includes recycling carbon fibers from a wind turbine blade section. In some embodiments, recycling carbon fibers from a wind turbine blade section includes burning pultrusions from spar caps to obtain recycled carbon fibers. In some embodiments, the recycled carbon fibers are chopped carbon fibers.

[0048] The needle felting manufacturing process provides certain properties to nonwoven fabrics that may not be achievable by other manufacturing processes. This is because with this technique, the fibers are entangled in a specific manner.

[0049] Accordingly, in a third aspect, a wind turbine component of the present invention can be obtained by the method according to the second aspect of the present invention.

[0050] In a fourth aspect, the present invention relates to a method of manufacturing a wind turbine blade that includes a wind turbine blade component such as a spar cap according to the first aspect of the present invention, wherein the method includes the steps of manufacturing a pressure side shell half and a suction side shell half over substantially the entire length of the wind turbine blade and then closing and joining the shell halves to obtain a closed shell, wherein manufacturing the pressure side shell half or the suction side shell half includes the steps of: - Providing a blade mold for a blade shell component, the blade mold including a molding surface; - Arranging a plurality of fiber reinforcement layers on the blade molding surface; - Providing a prefabricated laminated structure that includes a plurality of fiber reinforcement elements and a plurality of nonwoven fabrics embedded in a first curing resin and arranging the prefabricated laminated structure on the fiber reinforcement layers in the blade mold; or Stacking a plurality of fiber reinforcement elements on the fiber reinforcement layers in the blade mold, wherein a plurality of nonwoven fabrics are arranged between some of the fiber reinforcement elements; - Covering the plurality of fiber reinforcement elements and nonwoven fabrics in the blade mold to form a cavity and infusing the cavity with a first resin; - Optionally curing the resin to form a blade shell component, wherein the nonwoven fabric includes a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are randomly oriented carbon fibers entangled with the second plurality of fibers, and the second plurality of fibers are fibers of a type different from carbon fibers.

[0051] In some embodiments, the fiber reinforcement elements are pultrusions including carbon fibers and / or glass fibers, and wherein the nonwoven fabric is an interlayer arranged between each of the stacked pultrusions for facilitating resin infusion between the pultrusions.

[0052] In a fifth aspect, the present invention relates to a wind turbine blade comprising a wind turbine blade member according to the first aspect of the present invention.

[0053] The different aspects of the present invention may be combined with the different embodiments described above respectively. The embodiments and features described above for the different aspects of the present invention are equally applicable to other aspects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Embodiments of the present disclosure will be described in more detail below with reference to the drawings. The drawings illustrate one way of implementing the present disclosure and should not be construed as limiting other possible embodiments falling within the scope of the appended claims.

[0055] Figure 1 is a schematic view showing a wind turbine.

[0056] Figure 2 is a schematic view showing a wind turbine blade and a spar cap structure arranged within the wind turbine blade, Figure 3 is a schematic cross-sectional view showing a spar cap including a sandwich layer arranged between fiber reinforcement elements, and Figure 4 is a schematic cross-sectional view showing a nonwoven fabric including a plurality of carbon fibers entangled with a plurality of second fibers (such as polyester fibers). DETAILED DESCRIPTION

[0057] Various exemplary embodiments and details will be described below with reference to the drawings when relevant. It should be noted that the drawings may or may not be drawn to scale, and elements of similar structure or function are denoted by similar reference numerals in all the drawings. It should also be noted that the drawings are only intended to facilitate the description of the embodiments. They are not intended as an exhaustive description of the present invention or as a limitation on the scope of the present invention. Additionally, the illustrated embodiments do not necessarily have all the aspects or advantages shown. The aspects or advantages described in connection with a particular embodiment are not necessarily limited to that embodiment and may be practiced in any other embodiment, even if not so shown or even if not so explicitly described.

[0058] Figure 1 shows a conventional modern upwind wind turbine according to the so-called "Danish concept", which has a tower 400, a nacelle 600 and a rotor with a substantially horizontal rotor shaft. The rotor includes a hub 800 and three blades 1000 extending radially from the hub 800, each blade having a blade root 1600 closest to the hub and a blade tip 1400 furthest from the hub 800.

[0059] Figure 2A shows a schematic view of a first embodiment of a wind turbine blade 1000. The wind turbine blade 1000 has the shape of a conventional wind turbine blade and includes a root region 3000 closest to the hub, an airfoil or profile region 3400 furthest from the hub, and a transition region 3200 between the root region 3000 and the airfoil region 3400. The blade 1000 includes a leading edge 1800 facing the direction of rotation of the blade 1000 when the blade is mounted to the hub, and a trailing edge 2000 facing the opposite direction of the leading edge 1800.

[0060] The airfoil region 3400 (also referred to as the profile region) has a blade shape that is ideal or nearly ideal for generating lift, while the root region 3000 has a substantially circular or elliptical cross-section due to structural considerations, which for example makes it easier and safer to mount the blade 1000 to the hub. The diameter (or chord) of the root region 3000 may be constant along the entire root region 3000. The transition region 3200 has a transition profile that gradually changes from the circular or elliptical shape of the root region 3000 to the airfoil profile of the airfoil region 3400. The chord length of the transition region 3200 generally increases as the distance r from the hub increases. The airfoil region 3400 has an airfoil profile with a chord that extends between the leading edge 1800 and the trailing edge 2000 of the blade 1000. The width of the chord decreases as the distance r from the hub increases.

[0061] The shoulder 4000 of the blade 1000 is defined as the position where the blade 1000 has its maximum chord length. The shoulder 4000 is typically located at the boundary between the transition region 3200 and the airfoil region 3400.

[0062] It should be noted that the chords of the different sections of the blade generally do not lie in a common plane because the blade can twist and / or bend (i.e., pre-bend), and thus a corresponding twisted and / or bent path is provided to the chord plane to compensate for the most common case of the local speed of the blade depending on the radius from the hub.

[0063] Figure 2 B is a schematic view showing a cross-sectional view of an exemplary wind turbine blade 1000, for example, a cross-sectional view of the airfoil region of the wind turbine blade 1000. The wind turbine blade 1000 includes a leading edge 1800, a trailing edge 2000, a pressure side 2400, a suction side 2600, a first spar cap 10a, and a second spar cap 10b. The wind turbine blade 1000 includes a chord line 3800 between the leading edge 1800 and the trailing edge 2000. The wind turbine blade 1000 includes shear webs 4200, such as a leading edge shear web and a trailing edge shear web. Alternatively, the shear web 4200 may be a spar box having spar sides such as a trailing edge spar side and a leading edge spar side. The spar caps 10a, 10b may include carbon fiber, while the remaining parts of the shell portions 2400, 2600 may include glass fiber.

[0064] Figure 3 A is a schematic cross-sectional view showing a laminated structure 2, which includes a first fiber-reinforced element 30 and a second fiber-reinforced element 40, and a first nonwoven fabric 20 embedded in a first cured resin (not visible in the figure) and disposed between the first fiber-reinforced element 30 and the second fiber-reinforced element 40.

[0065] The nonwoven fabric 20 and the fiber-reinforced elements 30, 40 each have a length in the longitudinal direction, a width in the width direction, and a thickness in the thickness direction. The length is greater than the width, and the width is greater than the thickness. The width and length of the nonwoven fabric define the plane of the nonwoven fabric. In Figure 3 A, the width and thickness of the nonwoven fabric 20 and the fiber-reinforced elements can be seen, but the length cannot be seen.

[0066] In a preferred embodiment, the first fiber-reinforced element 30 and the second fiber-reinforced element 40 are pultruded carbon fiber elements, such as pultruded profiles, and the nonwoven fabric 20 is an interlayer for promoting resin infusion between the fiber-reinforced elements 30, 40. The first fiber-reinforced element 30, the second fiber-reinforced element 40, and the nonwoven fabric 20 together form the laminated structure 2, which can form a part of a wind turbine blade member 1, for example, disposed in a spar cap 10 in a wind turbine blade, such as the spar caps 10a, 10b of the wind turbine blade 1000 as shown in Figure 2 the figure.

[0067] Figure 3 B is a schematic exploded view showing Figure 3 A. In the illustrated example, the nonwoven fabric 20 includes a nonwoven fabric upper surface 21 and a nonwoven fabric lower surface 22. In the same way, the first fiber-reinforced element 30 has a first upper surface 31 and a first lower surface 32, and the second fiber-reinforced element 40 has a second upper surface 41 and a second lower surface 42.

[0068] The first fiber-reinforced element 30 and the second fiber-reinforced element 40 are arranged such that the first lower surface 32 of the first fiber-reinforced element 50 faces the second upper surface 41 of the second fiber-reinforced element 40. The nonwoven fabric 20 is disposed between the lower surface 32 of the first fiber-reinforced element 30 and the upper surface 41 of the second fiber-reinforced element 40, for example, such that the nonwoven fabric upper surface 21 contacts the first lower surface 32, and the nonwoven fabric lower surface 22 contacts the second upper surface 41. In a preferred embodiment, the nonwoven fabric includes chopped carbon fibers extending out of the fabric plane (see Figure 4 B).

[0069] Figure 3FIG. C is a schematic cross-sectional view showing a wind turbine blade member 1, which includes a laminated structure 2 (laminated structure) of fiber reinforcement elements and a nonwoven fabric 20. In this case, the wind turbine blade member 1 is a spar cap 10 for a wind turbine blade, such as the spar caps 10a, 10b of the wind turbine blade 1000 shown in Figure 2 as shown.

[0070] The wind turbine blade member 1, i.e., the spar cap 10, includes a laminated structure 2 (laminated structure) that includes a plurality of fiber reinforcement elements, such as pultruded profiles including carbon fibers and / or glass fibers. The plurality of fiber reinforcement elements includes a first fiber reinforcement element 30 and a second fiber reinforcement element 40. Each of the plurality of fiber reinforcement elements includes a plurality of stacked fiber reinforcement layers. The plurality of fiber reinforcement elements 30, 40 are arranged in an array, in which three rows of fiber reinforcement elements are arranged adjacent to each other. Each row includes three fiber reinforcement elements arranged adjacent to each other. These rows are separated by the nonwoven fabric 20. In this embodiment, the nonwoven fabric 20 is an interlayer for facilitating resin infusion between the plurality of fiber reinforcement elements. The interlayer is embedded in a first cured resin (not visible in the figure) to hold the laminated structure 2 together.

[0071] Of course, it is obvious that the spar cap 10 may include other numbers of layers and juxtaposed fiber reinforcement elements. Although not specifically shown, the nonwoven fabric 20 may also be provided between elements adjacent in the width direction to facilitate resin flow between the elements in this direction.

[0072] Although Figure 3 not shown in A-3C, the nonwoven fabric 20 of the wind turbine blade member 1 includes a plurality of first fibers 5 and a plurality of second fibers 6, wherein the plurality of first fibers 5 are randomly oriented carbon fibers entangled with the plurality of second fibers 6, and the second fibers 6 are fibers of a type different from carbon fibers.

[0073] Preferably, the nonwoven fabric 20 is a needle-punched felt nonwoven fabric. In such embodiments, the plurality of first fibers 5 and the plurality of second fibers 6 in the nonwoven fabric 20 are not held together by an adhesive or by stitching, as this is not necessary. However, the nonwoven fabric 20 may be reinforced by a stitching pattern, wherein the stitching pattern is made of a stitching thread including polyester fibers or consisting essentially of polyester fibers, and the stitching pattern includes a plurality of stitching rows for stabilizing the fabric for handling purposes.

[0074] Preferably, the plurality of carbon fibers are recycled or regenerated carbon fibers, wherein each of the plurality of carbon fibers has an average length between 10 mm and 100 mm, preferably between 30 mm and 70 mm, and the plurality of second fibers 6 are polymer fibers, preferably polyester fibers, having a diameter between 20 μm and 60 μm, such as 40 μm, and an average length between 20 and 100 mm. Preferably, the plurality of carbon fibers are recycled or regenerated carbon fibers, wherein each of the plurality of carbon fibers has an average length between 1 mm and 10 mm, preferably between 3 mm and 7 mm, and the plurality of second fibers 6 are polymer fibers, preferably polyester fibers, having a diameter between 20 μm and 60 μm, such as 40 μm, and an average length between 20 and 10 mm. Preferably, the ratio between the plurality of carbon fibers and the plurality of second fibers 6 in the nonwoven fabric 20 is between 1:3 and 3:1.

[0075] The nonwoven fabric 20 may further include a plurality of third fibers of a fiber type different from carbon fibers and polyester fibers.

[0076] Preferably, the nonwoven fabric 20 embedded in the first cured resin has a thickness between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.5 mm, such as 0.35 mm, and an areal weight between 50 g / m 2 and 200 g / m 2 preferably between 70 g / m 2 and 150 g / m 2 such as 75 g / m 2 、80 g / m 2 or 100 g / m 2 of the nonwoven fabric.

[0077] Figure 4 A is a schematic top view showing an embodiment of the nonwoven fabric 20, which can be used for the wind turbine blade member 1 according to the present invention.

[0078] As Figure 4 visible in A, the nonwoven fabric includes a plurality of first fibers 5 and a plurality of second fibers 6. As described with respect to Figure 3 C, the plurality of first fibers 5 are randomly oriented carbon fibers 5 entangled with the plurality of second fibers 6, and as also described with respect to Figure 3 C, the second fibers 6 are fibers of a type different from the carbon fibers 6, preferably polyester fibers.

[0079] For illustrative purposes, the dimensions of the plurality of first fibers and the plurality of second fibers are enlarged. The plurality of first fibers 5 (i.e., carbon fibers) are shown by black lines, and the plurality of second fibers (e.g., polyester fibers) are shown by gray lines. The plurality of first fibers and the plurality of second fibers have different lengths, but should respectively have average lengths between 1 mm and 100 mm and between 2 mm and 200 mm, such as between 1 mm and 10 mm and between 2 mm and 10 mm or between 10 mm and 100 mm and between 20 mm and 100 mm. In Figure 4 there are more of the first plurality of fibers than the second plurality of fibers, and the ratio of the plurality of carbon fibers 5 to the plurality of second fibers 6 in the nonwoven fabric 20 is about 3:1.

[0080] The entanglement of the fibers is not shown in a manner that resembles reality. Figure 4 A is merely a schematic view showing the presence of two different fiber types in the nonwoven fabric 20 according to an embodiment of the present invention.

[0081] Figure 4 B is a schematic cross-sectional view showing an embodiment of the nonwoven fabric 20, which can be used in the wind turbine blade member 1 according to the present invention.

[0082] Figure 4 Only the plurality of first fibers 5 are shown in B. The plurality of first fibers 5 are entangled and randomly oriented carbon fibers 5 as described with respect to Figure 3 C.

[0083] Each of the plurality of carbon fibers is covered in a sizing layer. The sizing layer is a very thin layer of chemical substance that improves the bonding between the plurality of carbon fibers in the nonwoven fabric and the fiber reinforcement layer (e.g., the pultruded carbon slats of the spar cap). It is known to those skilled in the art that carbon fibers used in the industry are typically covered with a sizing layer.

[0084] In Figure 4 B, the nonwoven fabric 20 includes chopped carbon fibers that protrude from the plane of the nonwoven fabric. In Figure 4In B, the planes from which the carbon fibers protrude are the nonwoven fabric upper surface 21 and the nonwoven fabric lower surface 22 of the nonwoven fabric. In this way, the ends of the chopped carbon fibers are configured to contact the fiber reinforcement layers 30, 40 (e.g., the carbon pultruded slats of the spar cap). The carbon fiber protruding planes are advantageous because the free ends of the chopped carbon fibers are not covered by a sizing layer. Therefore, the free ends of the chopped carbon fibers are configured to facilitate the circuit path between the nonwoven fabric 20 and the fiber reinforcement layers 30, 40 (e.g., the pultruded carbon slats of the spar cap). The carbon fibers 5 are preferably between 4 mm and 7 mm. If the carbon fibers 5 are longer, then fewer carbon fibers 5 protrude from the plane. That being said, chopped carbon fibers 5 of other lengths (e.g., shorter than 4 mm or longer than 7 mm respectively) will still contribute to out-of-plane fiber orientation and conductivity. Additionally, if the carbon fibers 5 are not chopped, the free ends of each of the carbon fibers 5 will be covered by a slightly insulating sizing layer.

[0085] The present disclosure has been described with reference to preferred embodiments. However, the scope of the invention is not limited to the illustrated embodiments, and modifications and variations can be made without departing from the scope of the invention. Throughout the description, the use of terms such as "first", "second", etc. does not imply any particular order or importance, but is included for the purpose of identifying separate elements. Additionally, the designation of a first element does not imply the presence of a second element, and vice versa.

[0086] Detailed list of embodiments: 1. A wind turbine blade component, the component comprising a laminated structure, the laminated structure comprising a nonwoven fabric, the nonwoven fabric comprising a plurality of first fibers and a plurality of second fibers, wherein the plurality of first fibers are randomly oriented carbon fibers entangled with the plurality of second fibers, and the plurality of second fibers are fibers of a type different from the carbon fibers.

[0087] 2. The wind turbine blade component according to item 1, wherein the nonwoven fabric is a needle-punched felt nonwoven fabric.

[0088] 3. The wind turbine blade component (1) according to any one of the preceding items, wherein the plurality of first fibers are entangled with the plurality of second fibers to such an extent that the nonwoven fabric can be handled and transported without other means to hold the fibers together.

[0089] 4. The wind turbine blade component according to any one of the preceding items, wherein the nonwoven fabric comprises chopped carbon fibers, and the ends of the chopped carbon fibers are not covered by a sizing layer.

[0090] 5. The wind turbine blade component according to any one of the preceding claims, wherein the carbon fibers protrude from the plane of the nonwoven fabric, preferably from the nonwoven fabric upper surface and / or the nonwoven fabric lower surface.

[0091] 6. The wind turbine blade component according to any one of the preceding items, wherein each of the plurality of first fibers (i.e., carbon fibers) has an average length between 10 mm and 100 mm, preferably between 30 mm and 70 mm.

[0092] 7. The wind turbine blade component according to any one of the preceding items, wherein the plurality of first fibers (i.e., carbon fibers) are recycled or regenerated carbon fibers.

[0093] 8. The wind turbine blade component according to any one of the preceding items, wherein the plurality of second fibers are polymer fibers, preferably polyester fibers.

[0094] 9. The wind turbine blade component according to any one of the preceding items, wherein the plurality of polyester fibers have a diameter between 20 μm and 60 μm, such as 40 μm.

[0095] 10. The wind turbine blade component according to any one of the preceding items, wherein the plurality of polyester fibers have an average length of 20 to 100 mm.

[0096] 11. The wind turbine blade component according to any one of the preceding items, wherein the non-woven fabric further comprises a plurality of third fibers of a fiber type different from carbon fibers and polyester fibers.

[0097] 12. The wind turbine blade component according to any one of the preceding items, wherein the ratio between the plurality of carbon fibers and the plurality of second fibers in the non-woven fabric is between 1:3 and 3:1.

[0098] 13. The wind turbine blade component according to any one of the preceding items, wherein the non-woven fabric is embedded in a first curing resin.

[0099] 14. The wind turbine blade component according to any one of the preceding items, wherein the first curing resin is an epoxy resin, a polyester resin, a polyurethane resin, or a vinyl ester resin.

[0100] 15. The wind turbine blade component according to any one of the preceding items, wherein the non-woven fabric has a thickness between 0.1 mm and 2 mm, preferably between 0.3 mm and 0.5 mm, such as 0.35 mm.

[0101] 16. The wind turbine blade component according to any one of the preceding items, wherein the non-woven fabric has a weight between 50 g / m 2 and 200 g / m 2 preferably between 70 g / m 2 and 150 g / m 2 such as 75 g / m 2 or 80 g / m 2or 100 g / m 2 areal weight.

[0102] 17. A wind turbine blade component according to any one of the preceding items, wherein the nonwoven fabric is reinforced by a stitching pattern.

[0103] 18. A wind turbine blade component according to any one of the preceding items, wherein the stitching pattern is made of a stitching thread comprising polyester fibers or consisting essentially of polyester fibers.

[0104] 19. A wind turbine blade component according to any one of the preceding items, wherein the stitching pattern includes a plurality of stitching rows for stabilizing the fabric for handling purposes.

[0105] 20. A wind turbine blade component according to any one of the preceding items, wherein the plurality of stitching rows are arranged along the longitudinal direction and / or the transverse direction of the nonwoven fabric.

[0106] 21. A wind turbine blade component according to any one of the preceding items, wherein multiple first fibers and multiple second fibers in the nonwoven fabric are not held together by an adhesive or by stitching.

[0107] 22. A wind turbine blade component according to any one of the preceding items, wherein the laminated structure further comprises - a plurality of fiber reinforcement elements, including a first fiber reinforcement element and a second fiber reinforcement element; and - a plurality of nonwoven fabrics, including a first nonwoven fabric embedded in a first cured resin and disposed between the first fiber reinforcement element and the second fiber reinforcement element.

[0108] 23. The wind turbine blade component according to item 22, wherein each of the plurality of fiber reinforcement elements comprises a plurality of stacked fiber reinforcement layers.

[0109] 24. The wind turbine blade component according to item 22 or 23, wherein the plurality of fiber reinforcement elements are pre-cured fiber reinforcement elements, such as pultruded profiles comprising carbon fibers and / or glass fibers.

[0110] 25. The wind turbine blade component according to any one of items 22 - 24, wherein the plurality of nonwoven fabrics are interlayers for facilitating resin infusion between the plurality of fiber reinforcement elements.

[0111] 26. The wind turbine blade component according to any one of items 22 - 25, wherein the first cured resin is an epoxy resin, a polyester resin, a polyurethane resin, or a vinyl ester resin.

[0112] 27. A wind turbine blade component according to any one of the preceding items, wherein the wind turbine blade component is a spar cap.

[0113] 28. A method of manufacturing a wind turbine blade component, such as a spar cap, the method comprising the steps of: - providing a plurality of fiber reinforcement elements, including a first fiber reinforcement element (30) and a second fiber reinforcement element; - providing a plurality of nonwoven fabrics, including a first nonwoven fabric, the first nonwoven fabric including a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are randomly oriented carbon fibers entangled with the second plurality of fibers, and the second plurality of fibers are fibers of a type different from carbon fibers, - arranging the first nonwoven fabric between the first fiber reinforcement element and the second fiber reinforcement element such that the fiber reinforcement elements are separated by the first nonwoven fabric; - injecting a first resin between the plurality of fiber reinforcement elements and the plurality of nonwoven fabrics; - curing the resin to form a wind turbine blade component.

[0114] 29. The method of manufacturing a wind turbine blade component, such as a spar cap, according to item 28, wherein the step of providing the first nonwoven fabric comprises the steps of: - providing a plurality of webs or felts including a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are carbon fibers and the second plurality of fibers are fibers of a type different from carbon fibers, and - needling and felting the first plurality of fibers and the second plurality of fibers to entangle the fibers until a predetermined areal weight is obtained.

[0115] 30. The method of manufacturing a wind turbine blade component according to item 29, wherein each of the plurality of fiber reinforcement elements includes a plurality of stacked fiber reinforcement layers.

[0116] 31. The method of manufacturing a wind turbine blade component according to any one of items 29 or 30, wherein the plurality of fiber reinforcement elements are pre-cured fiber reinforcement elements, such as pultruded profiles including carbon fibers and / or glass fibers.

[0117] 32. The method of manufacturing a wind turbine blade component according to any one of items 28-31, wherein the plurality of nonwoven fabrics are interlayers for facilitating resin injection between the plurality of fiber reinforcement elements.

[0118] 33. The method of manufacturing a wind turbine blade component according to any one of items 28-32, wherein the first cured resin is an epoxy resin, a polyester resin, a polyurethane resin, or a vinyl ester resin.

[0119] 34. A method of manufacturing a wind turbine blade component according to any one of items 28 - 33, wherein the carbon fiber is recycled carbon fiber, and the step of providing the recycled carbon fiber includes recovering carbon fiber from a wind turbine blade part.

[0120] 35. A method of manufacturing a wind turbine blade component according to any one of items 29 - 34, wherein recovering carbon fiber from a wind turbine blade part includes burning pultruded profiles from a spar cap to obtain recycled carbon fiber.

[0121] 36. A method of manufacturing a wind turbine blade component according to any one of items 32 - 35, wherein the recycled carbon fiber is chopped carbon fiber.

[0122] 37. A method of manufacturing a wind turbine blade, the wind turbine blade including a wind turbine blade component such as a spar cap according to any one of items 1 - 27, the method including the steps of: manufacturing a pressure side shell half and a suction side shell half over substantially the entire length of the wind turbine blade, and then closing and joining the shell halves to obtain a closed shell, wherein manufacturing the pressure side shell half or the suction side shell half includes the steps of: - providing a blade mold for a blade shell component, the blade mold including a molding surface; - arranging a plurality of fiber - reinforced layers on the blade molding surface; - providing a pre - fabricated laminated structure, the pre - fabricated laminated structure including a plurality of fiber - reinforced elements and a plurality of non - woven fabrics embedded in a first curing resin, and arranging the pre - fabricated laminated structure on the fiber - reinforced layers in the blade mold; or stacking a plurality of fiber - reinforced elements on the fiber - reinforced layers in the blade mold, wherein a plurality of non - woven fabrics are arranged between some of the fiber - reinforced elements; - covering the plurality of fiber - reinforced elements and non - woven fabrics in the blade mold with a cover to form a cavity, and infusing the cavity with a first resin; - optionally curing the resin to form a blade shell component, wherein the non - woven fabric includes a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are randomly - oriented carbon fibers entangled with the second plurality of fibers, and the second plurality of fibers are fibers of a type different from carbon fibers.

[0123] 38. A method of manufacturing a wind turbine blade including a spar cap according to item 37, wherein the fiber - reinforced elements are pultruded profiles including carbon fiber and / or glass fiber, and wherein the non - woven fabric is an interlayer arranged between each of the stacked pultruded profiles for facilitating resin infusion between the pultruded profiles.

[0124] 39. A wind turbine blade, comprising a wind turbine blade member according to any one of claims 1 - 27. List of reference numerals 200 Wind turbine 400 Tower 600 Nacelle 800 Hub 1000 Blade 1400 Blade tip 1600 Blade root 1800 Leading edge 2000 Trailing edge 2200 Pitch axis 2400 Pressure side 2600 Suction side 3000 Root region 3200 Transition region 3400 Airfoil region 4000 Location of shoulder / maximum chord 4200 Shear web 1 Wind turbine blade member 2 Laminated structure 5 Multiple first fibers, i.e., carbon fibers 6 Multiple second fibers, e.g., polyester fibers 10 Spar cap 10a First spar cap 10b Second spar cap 20 Non - woven fabric, e.g., for sandwich in spar cap 21 Non - woven fabric upper surface 22 Non - woven fabric lower surface 30 First fiber - reinforced element, e.g., pultrusion for spar cap 31 First upper surface 32 First lower surface 40 Second fiber - reinforced element, e.g., pultrusion for spar cap 41 Second upper surface 42 Second lower surface

Claims

1. A component of a wind turbine blade (1), the component comprising a laminated structure (2), the laminated structure comprising a nonwoven fabric (20), the nonwoven fabric comprising a plurality of first fibers (5) and a plurality of second fibers (6), wherein the plurality of first fibers (5) are randomly oriented carbon fibers entangled with the plurality of second fibers (6), and the plurality of second fibers are fibers of a type different from carbon fibers.

2. The wind turbine blade component (1) according to claim 1, wherein the nonwoven fabric (20) is a needled felt nonwoven fabric.

3. The wind turbine blade component (1) according to any one of the preceding claims, wherein the plurality of first fibers are entangled with the plurality of second fibers to such an extent that the nonwoven fabric can be handled and transported without other means to hold the fibers together.

4. The wind turbine blade component (1) according to any one of the preceding claims, wherein the plurality of first fibers (5) are recycled or regenerated carbon fibers, and / or wherein the plurality of second fibers (6) are polymer fibers, preferably polyester fibers.

5. The wind turbine blade component according to any one of the preceding claims, wherein the nonwoven fabric comprises chopped carbon fibers, and the ends of the chopped carbon fibers are not covered by a sizing layer, and / or wherein the carbon fibers protrude from the plane of the nonwoven fabric, preferably from the upper surface and / or the lower surface of the nonwoven fabric.

6. The wind turbine blade component (1) according to any one of the preceding claims, wherein each of the plurality of first fibers (5) has an average length between 10 mm and 100 mm, preferably between 30 mm and 70 mm, and / or wherein the plurality of second fibers (6) have a diameter between 20 μm and 60 μm, and / or wherein the plurality of second fibers have an average length between 20 and 100 mm.

7. The wind turbine blade component (1) according to any one of the preceding claims, wherein the ratio of the plurality of first fibers (5) to the plurality of second fibers (6) in the nonwoven fabric (20) is between 1:3 and 3:1 by volume %.

8. The wind turbine blade component (1) according to any one of the preceding claims, wherein the nonwoven fabric (20) has an areal weight between 50 g / m 2 and 200 g / m 2 preferably between 70 g / m 2 and 150 g / m 2 ​9. The wind turbine blade component (1) according to any one of the preceding claims, wherein a plurality of first fibers (5) and a plurality of second fibers (6) in the nonwoven fabric (20) are not held together by an adhesive or by stitching.

10. The wind turbine blade component (1) according to any one of the preceding claims, wherein the laminated structure (2) further comprises - a plurality of fiber reinforcement elements, comprising a first fiber reinforcement element (30) and a second fiber reinforcement element (40); and - a plurality of nonwoven fabrics (20), comprising a first nonwoven fabric (20) embedded in a first cured resin and arranged between the first fiber reinforcement element (30) and the second fiber reinforcement element (40).

11. The wind turbine blade component (1) according to claim 10, wherein each of the plurality of fiber reinforcement elements (30, 40) comprises a plurality of stacked fiber reinforcement layers, and / or wherein the plurality of fiber reinforcement elements are pre-cured fiber reinforcement elements, such as pultruded profiles comprising carbon fibers and / or glass fibers, and / or wherein the plurality of nonwoven fabrics (20) are interlayers for facilitating resin infusion between the plurality of fiber reinforcement elements.

12. The wind turbine blade component (1) according to any one of the preceding claims, wherein the wind turbine blade component is a spar cap (10).

13. A method of manufacturing a wind turbine blade component such as a spar cap (10), the method comprising the steps of: - Provide a plurality of fiber reinforcement elements, which include a first fiber reinforcement element (30) and a second fiber reinforcement element (40); - Provide a plurality of nonwoven fabrics (20), which include a first nonwoven fabric (20), and the first nonwoven fabric (20) includes a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are randomly oriented carbon fibers entangled with the second plurality of fibers, and the second plurality of fibers are fibers of a type different from carbon fibers; - Arrange the first nonwoven fabric (20) between the first fiber reinforcement element (30) and the second fiber reinforcement element (40) such that the fiber reinforcement elements (30, 40) are separated by the first nonwoven fabric (20); - Infuse a first resin between the plurality of fiber reinforcement elements and the plurality of nonwoven fabrics (20); - Cure the resin to form the wind turbine blade member (10).

14. The method of manufacturing a wind turbine blade component (1) such as a spar cap (10) according to claim 13, wherein the step of providing the first nonwoven fabric (20) comprises the steps of: - Provide a plurality of meshes or felts including a first plurality of fibers and a second plurality of fibers, wherein the first plurality of fibers are carbon fibers, and the second plurality of fibers are fibers of a type different from carbon fibers, and - Needle felt the first plurality of fibers and the second plurality of fibers to entangle the fibers until a predetermined areal weight is obtained.

15. A method of manufacturing a wind turbine blade component (1) according to claim 14, wherein each of the plurality of fiber reinforced elements comprises a plurality of stacked fiber reinforced layers, and wherein the plurality of fiber reinforced elements are pre-cured fiber reinforced elements, such as pultruded profiles comprising carbon fiber and / or glass fiber, and wherein the large number of non-woven fabrics (20) are interlayers for facilitating resin infusion between the plurality of fiber reinforced elements.

16. A method of manufacturing a wind turbine blade component (1) according to any one of claims 13 to 15, wherein the plurality of first fibers (5) are recycled carbon fibers, and the step of providing the recycled carbon fibers comprises recovering carbon fibers from a wind turbine blade part.

17. A wind turbine blade comprising a wind turbine blade component according to any one of claims 1 to 12.

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