METHOD FOR MANUFACTURING A WIND TURBINE BLADE

Abstract

A method for manufacturing a wind turbine blade, includes the steps of: arranging an upper mould including a pre-casted fibre lay-up on a lower mould comprising a dry fibre lay-up and a mould core, applying vacuum to a space between the upper and lower moulds and the mould core, infusing at least the dry fibre lay-up and a connection region between the dry fibre lay-up and the pre-casted fibre lay-up with a resin, and curing the resin.

By having the pre-casted fibre lay-up in the upper mould, the packing and positioning of dry composite materials on top of the mould core is avoided.

Claims

1. A method for manufacturing a wind turbine blade, comprising the steps of: arranging an upper mould comprising a pre-casted fibre lay-up on a lower mould comprising a dry fibre lay-up and a mould core, applying vacuum to a space between the upper and lower moulds and the mould core, and infusing at least the dry fibre lay-up and a connection region between the dry fibre lay-up and the pre-casted fibre lay-up with a resin, and curing the resin.

2. The method according to claim 1, wherein the dry fibre lay-up and/or the pre-casted fibre lay-up includes a core material.

3. The method according to claim 1, wherein the connection region comprises an overlap region in which the pre-casted fibre lay-up and the dry fibre lay-up overlap each other.

4. The method according to claim 2, wherein the pre-casted fibre lay-up and/or the dry fibre lay-up comprises the core material in the overlap region.

5. The method according to claim 3, wherein both the dry fibre lay-up and the pre-casted fibre lay-up comprise at least one tapered edge portion overlapping each other in the overlap region.

6. The method according to claim 1, wherein the pre-casted fibre lay-up and the dry fibre lay-up are in direct contact with each other in the connection region.

7. The method according to claim 1, wherein an auxiliary material is disposed between a surface of at least one edge portion of the pre-casted fibre lay-up and a surface of at least one edge portion of the dry fibre lay-up.

8. The method according to claim 1, wherein the dry fibre lay-up in the lower mould has a main portion inside a cavity of the lower mould and at least one extending portion extending from the main portion beyond a side edge of the cavity of the lower mould, and wherein the method comprises, before the step of arranging the upper mould on the lower mould, the steps of arranging the mould core on the dry fibre lay-up in the lower mould and folding up the at least one extending portion of the dry fibre lay-up onto the mould core.

9. The method according to claim 8, wherein a continuation portion of the at least one extending portion has the same layer structure and/or the same thickness as the main portion, the continuation portion being continuous with the main portion.

10. The method according to claim 8, comprising, after the step of folding up the at least one extending portion onto the mould core, the step of fixing the at least one folded-up extending portion at the mould core.

11. The method according to claim 1, comprising, before the step of arranging the upper mould comprising the pre-casted fibre lay-up on the lower mould, the step of fixing the pre-casted fibre lay-up to the upper mould.

12. The method according to claim 1, comprising, before the step of applying vacuum, the step of covering the mould core with a vacuum bag, and wherein the vacuum is applied to a space between the upper and lower moulds and the vacuum bag.

13. The method according to claim 1, comprising, before the step of arranging the upper mould on the lower mould, the step of arranging one or more reinforcement beams on the dry fibre lay-up.

14. The method according to claim 1, comprising, before the step of arranging the upper mould on the lower mould, the step of arranging a web, and wherein at least the dry fibre lay-up, the connection region and the web is infused with resin.

15. The method according to claim 14, wherein the web is configured to transversally connect the pre-casted fibre lay-up and the dry fibre lay-up, once cured, within an interior cavity of the blade.

Description

BRIEF DESCRIPTION

[0074] Some of the embodiments will be described in detail, with reference to the following figures, wherein like designations denote like members, wherein:

[0075] FIG. 1 shows a wind turbine according to an embodiment;

[0076] FIG. 2 shows a cross-section view of a pre-casted fibre lay-up forming a first shell of a blade of the wind turbine of FIG. 1, the pre-casted fibre lay-up being manufactured in an upper mould turned upside down;

[0077] FIG. 3 shows a cross-section view of a dry fibre lay-up forming, once casted and cured, a second shell of the blade of the wind turbine of FIG. 1, the dry fibre lay-up being arranged in a lower mould;

[0078] FIG. 4 shows a view similar as FIG. 3 with a mould core and a web arranged on the dry fibre lay-up in the lower mould;

[0079] FIG. 5 shows a view similar as FIG. 4 with extending portions of the dry fibre lay-up being folded up onto the mould core;

[0080] FIG. 6 shows the upper mould with the pre-casted fibre lay-up of FIG. 2 during arrangement on the lower mould with the dry fibre lay-up of FIG. 5;

[0081] FIG. 7 shows a view similar as FIG. 6 with the upper mould being arranged on the lower mould, wherein the pre-casted fibre lay-up is overlapping with the dry fibre lay-up in an overlap region;

[0082] FIG. 8 shows a view similar as FIG. 7 with resin infused;

[0083] FIG. 9 shows a further embodiment of an overlap of a pre-casted fibre lay-up and a dry fibre lay-up;

[0084] FIG. 10 shows another embodiment of an overlap of a pre-casted fibre lay-up and a dry fibre lay-up; and

[0085] FIG. 11 shows a flowchart illustrating a method for manufacturing the wind turbine blade of the wind turbine of FIG. 1.

DETAILED DESCRIPTION

[0086] In the figures, like reference numerals designate like or functionally equivalent elements, unless otherwise indicated.

[0087] FIG. 1 shows a wind turbine 1 according to an embodiment. The wind turbine 1 comprises a rotor 2 having one or more blades 3 connected to a hub 4. The hub 4 is connected to a generator (not shown) arranged inside a nacelle 5. During operation of the wind turbine 1, the blades 3 are driven by wind to rotate and the wind's kinetic energy is converted into electrical energy by the generator in the nacelle 5. The nacelle 5 is arranged at the upper end of a tower 6 of the wind turbine 1. The tower 6 is erected on a foundation 7 such as a monopile or tripile. The foundation 7 is connected to and/or driven into the ground or seabed.

[0088] In the following an improved method for manufacturing a wind turbine blade 3 is described with respect to FIGS. 2 to 11.

[0089] In step S1 of the method, and upper mould 8 is provided for pre-casting a fibre lay-up 9′, as shown in FIG. 2. The pre-casted fibre lay-up 9″, once cured and assembled, will become a first shell 10 of the manufactured blade 3 (FIG. 7). For step S1, the upper mould 8 is turned upside down, as shown in FIG. 2. A mould cavity 11 of the upper mould 8 is packed with dry fibre lay-up 9′. Since the upper mould 8 is turned upside down, the fibre lay-up 9′ can be packed towards a well-defined geometry, in contrast to the case in which a fibre lay-up is packed onto a flexible mould core.

[0090] The fibre lay-up 9′, 9″ in the example of FIG. 2 comprises an outer laminate 12 and an inner laminate 13. Further, the fibre lay-up 9′, 9″ comprises a core material, e.g., a balsa core, between the outer laminate 12 and the inner laminate 13. Here, it comprises a trailing edge balsa core 14 and a leading edge balsa core 15. The outer laminate 12, the respective balsa core 14, 15, and the inner laminate 13 form a sandwich structure.

[0091] The fibre lay-up 9′, 9″ has a first tapered portion 17 and a second tapered portion 18 at its left and right edges in FIG. 2. In each of these tapered portions 17, 18, the inner laminate 13, the respective balsa core 14, 15, and the outer laminate 12 is tapered. Hence, the tapered portions 17, 18 each have a continuous inclined surface 19, 20.

[0092] The fibre lay-up 9′, 9″ in FIG. 2 further comprises a pre-casted beam 16. The beam 16 is, for example, a suction-side beam or a pressure-side beam of the blade 3.

[0093] The dry fibre lay-up 9′ is pre-casted by a known vacuum infusion process, as described in EP 1 310 351 A1. In this vacuum infusion process, the fibre lay-up 9′ is covered with a vacuum bag (not shown), and the vacuum bag is sealed (not shown) at horizontal portions 21, 22 of the upper mould 8. Further, a vacuum is generated in a space covered by the vacuum bag, resin (not shown) is infused into the fibre lay-up 9′ and cured, resulting in the pre-casted fibre lay-up 9″ shown in FIG. 2.

[0094] In step S2 of the method, a lower mould 23 is provided, as shown in FIG. 3. The lower mould 23 is packed with a dry fibre lay-up 24′.

[0095] The dry fibre lay-up 24′ comprises an outer laminate 25 and an inner laminate 26. Further, the dry fibre lay-up 24′ comprises a core material, such as a leading edge balsa core 27 and a trailing edge balsa core 28. Hence, the fibre lay-up 24′ has a sandwich structure, wherein a respective balsa core 27, 28 is sandwiched in between outer and inner laminates 25, 26.

[0096] The fibre lay-up 24′ further comprises a pre-casted beam 29. The beam 29 is, for example, a pressure-side beam or a suction-side beam of the blade 3.

[0097] The lower mould 23 comprises a mould cavity 30 and horizontal portions 31, 32 extending from side edges 33, 34 of the mould cavity 30.

[0098] The dry fibre lay-up 24′ is packed into the lower mould 23 by arranging a main portion 35 of the dry fibre lay-up 24′ inside the cavity 30. In this example, the main portion 35 comprises a first main portion 36 and a second main portion 37. The first main portion 36 is arranged to the left side in FIG. 3 of the beam 29. The second main portion 37 is arranged to the right side in FIG. 3 of the beam 29.

[0099] Further, extending portions 38, 39 of the dry fibre lay-up 24′ extend from the main portion 35, i.e. from the first main portion 36 and the second main portion 37, beyond the side edges 33, 34 of the cavity 30, respectively.

[0100] The extending portion 38 comprises a first continuation portion 40 and a first tapered portion 42. The extending portion 39 comprises a second continuation portion 41 and a second tapered portion 43.

[0101] In this example, the continuation portion 40 has the same layer structure of the outer laminate 25, the leading edge balsa core 27, and the inner laminate 26 as the first main portion 36 of the fibre lay-up 24′. Further, the continuation portion 40 has the same thickness d1 as the first main portion 36. Furthermore, the continuation portion 41 has the same layer structure of the outer laminate 25, the trailing edge balsa core 28, and the inner laminate 26 as the second main portion 37 of the fibre lay-up 24′. Further, the continuation portion 41 has the same thickness d2 as the second main portion 37.

[0102] In each of the first and second tapered portions 42, 43, the inner laminate 26, the respective balsa core 27, 28, and the outer laminate 25 are tapered. Hence, the tapered portions 42, 43 each have a continuous inclined surface 44, 45.

[0103] In step S3 of the method, a mould core 46 is arranged on the dry fibre lay-up 24′, as shown in FIG. 4. The mould core 46 comprises a first mould core portion 47 and a second mould core portion 48. Each of the first and second mould core portions 47, 48 comprises, for example, a firm inner core 49, 50, and a flexible external portion 51, 52. The flexible external portions 51, 52 comprise, for example, a foam material which can be compressed.

[0104] Before arranging the mould core portions 47, 48, each of them is covered with a vacuum bag 53, 54, as shown in FIG. 4. The vacuum bags 53, 54 are sealed.

[0105] In step S4 of the method, a shear web 55 is provided on the dry fibre lay-up 24′ and in between the first and second mould core portions 47 and 48. In the example shown in the figures, the web 55 is a dry lay-up. In other examples, the web 55 may also be pre-casted.

[0106] Step S4 may be performed simultaneously with step S3 of arranging the mould core portions 47, 48.

[0107] In step S5 of the method, the extending portions 38, 39 of the dry fibre lay-up 24′ are folded up onto the respective first and second mould core portions 47, 48 of the mould core 46, as shown in FIG. 5.

[0108] In step S6 of the method, the extending portions 38, 39 are fixed to the respective first and second mould core portions 47, 48. In detail, the extending portion 38 is fixed to the first mould core portion 47 covered with the vacuum bag 53 by means of a first adhesive tape 56. Further, the extending portion 39 is fixed to the second mould core portion 48 covered with the vacuum bag 54 by means of a second adhesive tape 57.

[0109] In step S7 of the method, the pre-casted fibre lay-up 9″, which was pre-casted in the upper mould 8 in step Si (FIG. 2), is fixed to the upper mould 8. The pre-casted fibre lay-up 9″ is, for example and as shown in FIG. 6, fixed to the upper mould 8 by means of attaching a first foil 58 and a second foil 59 each to the pre-casted fibre lay-up 9″ and the upper mould 8. The foils 58, 59 are sealed. FIG. 6 shows as example sealings 60. A vacuum is generated in a space covered by the foils 58, 59 which holds the pre-casted fibre lay-up 9″ in the upper mould 8 while turning it and lowering it onto the lower mould 23 in the next step.

[0110] Step S1 and S7 may be performed before steps S2 to S6, simultaneously with steps S2 to S6, or after steps S2 to S6.

[0111] In step S8 of the method, the upper mould 8 is arranged on the lower mould 23, as shown in FIG. 6. Arranging the upper mould 8 on the lower mould 23 includes turning the upper mould 8 from the position in FIG. 2 to the position in FIG. 6. FIG. 6 shows a state in which the fibre lay-up 9″ is already fixed to the upper mould 8, and the upper mould 8 is lifted, turned around and is being lowered onto the lower mould 23.

[0112] FIG. 7 shows a state in which the upper mould 8 has been arranged on the lower mould 23. The pre-casted fibre lay-up 9″ and the dry fibre lay-up 24′ overlap each other in both a first and a second overlap region 61, 62. FIG. 7 shows an insert with an enlarged view of the overlap region 61. In particular, the tapered portion 18 of the pre-casted fibre lay-up 9″ and the tapered portion 42 of the dry fibre lay-up 24′ are overlapping each other in the overlap region 61. Thereby, the inclined surface 20 of the tapered portion 18 and the inclined surface 44 of the tapered portion 42 are in direct contact with each.

[0113] Similar, the tapered portion 17 of the pre-casted fibre lay-up 9″ and the tapered portion 43 of the dry fibre lay-up 24′ are overlapping each other in the overlap region 62. Thereby, the inclined surface 19 of the tapered portion 17 and the inclined surface 45 of the tapered portion 43 are in direct contact with each.

[0114] In this example, as can be seen in the insert of FIG. 7, the layer structure of the pre-casted fibre lay-up 9″ including the outer and inner laminates 12, 13 and the respective core material 14, 15 match the layer structure of the dry fibre lay-up 24′ including the outer and inner laminates 25, 26 and the respective core material 27, 28.

[0115] In step S9 of the method, a vacuum is generated in a space 63 defined by the upper and lower moulds 8, 23 and the vacuum bags 53, 54 covering the mould core portions 47, 48, as shown in FIG. 8.

[0116] In step S10, resin 65 is introduced in the space 63. In particular, the resin 65 is introduced in that part of the space 63 comprising the dry fibre lay-up 24′, the connection regions 66, 67, and the web 55. The resin 65 is, for example, introduced by a vacuum infusion process such as Vacuum Assisted Resin Transfer Moulding (VARTM). For further details of the generation of the vacuum, the infusion and curing of the resin 65, it is referred to EP 1 310 351 A1.

[0117] The example illustrated in the figures shows a case where the web 55 is a dry lay-up. In this case, the web 55 is entirely infused with the resin 65, as shown.

[0118] In other examples, a pre-casted web instead of the web 55 may be used. Then, the resin 65 would only be infused in an upper and lower connection portion of such a web (i.e. in a region where such a web would be connected with the beam 16 and in a region where such a web would be connected with the beam 29) but not in a vertical portion of such a web.

[0119] FIG. 8 shows exemplary inlet channels 64 through which the resin 65 is infused. With the drawn-in resin 65, the dry fibre lay-up 24′, the connection regions 66, 67 (between the dry fibre lay-up 24′ and the pre-casted fibre lay-up 9″), and the web 55 are casted in a single process step.

[0120] Each of the connection regions 66, 67 includes, in particularly, the respective overlap region 61, 62. In this example, the connection regions 66, 67 are larger than the overlap regions 61, 62, respectively. In another embodiment, the connection regions 66, 67 and overlap regions 61, 62 may be the same, respectively.

[0121] As the fibre lay-up 9″ in the upper mould 8 is pre-casted, the resin 65 has to only fill the dry fibre lay-up 24′, the connection regions 66, 67 and the web 55 but not the remaining portion of the pre-casted fibre lay-up 9″ during the vacuum infusion process in step S9. Thus, the resin 65 has to travel a shorter path and fill a smaller volume compared to the case in which a fibre lay-up in the upper mould 8 is in a dry condition, i.e. without resin.

[0122] In step S11, the infused resin 65 is cured by a known process to obtain a cured and assembled blade shell. As shown in FIG. 8, the pre-casted fibre lay-up 9″ in the upper mould 8 becomes in the manufactured blade 3 the first half shell 10. Further, the fibre lay-up 24″ in the lower mould 23 becomes, once infused and cured, in the manufactured blade 3 a second half shell 68. The web 55, once cured, transversally connects the first half shell 10 and the second half shell 68 within an interior cavity 71 of the blade 3.

[0123] In this example, the resulting fibre-reinforced resin laminate of the shells 10, 68 has the same structure comprising the inner laminates 13, 26, the core materials 14, 15, 27, 28, and the outer laminates 12, 25 throughout the overlap regions 61, 62 and the connection regions 66, 67. Therefore, a blade 3 having a shell with homogenous properties, such as homogenous strength and weight, across the overlap and connection regions 61, 62, 66, 67 is obtained.

[0124] In step S12 (not shown), the mould core portions 47, 48 and the vacuum bags 53, 54 are removed from the blade 3, e.g., through a root section of the blade 3.

[0125] With this method, a blade is manufactured in which the first and second shells 10, 68 are connected with each other by a laminate joint which is a light and at the same time strong joint.

[0126] In a further embodiment, as shown in FIG. 9, an overlap region 161 of a pre-casted fibre lay-up 109″ in an upper mould 108 and a dry fibre lay-up 124′ in a lower mould 123 does not contain a core material 115, 127. Thus, in the overlap region 161, the outer and inner laminates 112, 113 of the pre-casted lay-up 109″ overlap with the outer and inner laminates 125, 126 of the fibre lay-up 124′, 124″ in the lower mould 123. However, the core material 115 of the pre-casted fibre lay-up 109″ does not overlap with the core material 127 of the fibre lay-up 124′, 124″ in the lower mould 123.

[0127] In a further embodiment, as shown in FIG. 10, an auxiliary material 69 is disposed in an overlap region 262 of a pre-casted fibre lay-up 209″ in an upper mould 208 and a fibre lay-up 224′, 224″ in a lower mould 223. The auxiliary material 69 is, for example, a PUR material. It is applied in the example of FIG. 10 to form a sharp edge 70 of an aerodynamic profile of the blade 3, e.g. at a trailing edge of the airfoil.

[0128] The auxiliary material 69 is arranged in the example of FIG. 10 between an inclined surface 219 of a tapered edge portion 217 of the pre-casted fibre lay-up 209″ and an inclined surface 245 of a tapered edge portion 243 of the fibre lay-up 224′, 224″ in the lower mould 223. Furthermore, a mini-web 229 is arranged connecting the pre-casted fibre lay-up 209″, the auxiliary material 69 and the fibre lay-up 224′, 224″.

[0129] Although the present invention has been disclosed in the form of preferred embodiments and variations thereon, it will be understood that numerous additional modifications and variations could be made thereto without departing from the scope of the invention.

[0130] For the sake of clarity, it is to be understood that the use of “a” or “an” throughout this application does not exclude a plurality, and “comprising” does not exclude other steps or elements.