Thermoplastic Blade Joint Welding for Lighter Wind Turbine Assembly

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Solution Overview

Problem

The challenges in manufacturing large wind turbine blades include the complexity and weight of metal joints, fatigue and corrosion issues, long curing times for adhesive joints, and the difficulty in transporting and assembling large mold components.

Innovation Solution

The method involves using thermoplastic materials for edge joining portions of composite elements, which are plastic welded to form wind turbine blades, reducing the need for adhesives and allowing for efficient assembly and repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metal parts are used to join blade segments, then the blade segments can be connected structurally, but the weight of the wind turbine blade increases and the joints suffer from fatigue and corrosion

Engineering Contradiction:
Improvejoint strengthVSAvoidblade weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from metal to thermoplastic composite, transforming the joining method from metallic fastening to thermoplastic welding. This parameter change eliminates the weight penalty of metal parts while maintaining joint strength through the thermoplastic material's mechanical properties and welding characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials (thermoplastic matrix with fibers) for the joining portions instead of metal parts. The composite material provides both the necessary structural strength for joining and reduces weight compared to metal, while also eliminating corrosion issues inherent to metallic joints.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If adhesive or glue is used to join blade parts, then the parts can be connected, but the preparation process becomes complex and curing time increases

Engineering Contradiction:
Improvejoining process simplicityVSAvoidcuring time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The patent replaces the chemical bonding mechanism of adhesives with a thermal-mechanical welding process. Instead of relying on chemical curing reactions that take time, the thermoplastic welding uses heat to melt and fuse materials, followed by mechanical pressing, which significantly reduces the joining time and eliminates complex surface preparation requirements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Length of moving object

If larger molds are used to manufacture larger wind turbine blades, then larger blades can be produced, but transporting the blades becomes more difficult

Engineering Contradiction:
Improveblade lengthVSAvoidtransportability
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The patent divides the blade manufacturing process into segments that can be produced separately in smaller molds and then joined together using thermoplastic welding. This segmentation allows each segment to be manufactured in manageable sizes for easy transport, while the thermoplastic joining process creates strong connections that match or exceed the strength of monolithic blade construction.

Inventive Principle:
Principle #1Segmentation

4Ease of operation

If more molds with reduced size are used to manufacture wind turbine blades, then the blade can be assembled from smaller parts, but the number of joining operations increases

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidnumber of joining operations
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges multiple blade segments through thermoplastic welding into a unified structural assembly. The welding process combines the segments so effectively that the final product achieves monolithic-like structural integrity, making the multiple joining operations invisible in the finished product and eliminating the need for visible fasteners or adhesive joints.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances structural integrity, reduces weight, and simplifies the manufacturing process while enabling easier maintenance and recycling of wind turbine blades.

Implementation Method 1

Each of the first and the second composite elements comprises one or more edge joining portions having a thermoplastic material. The method comprises positioning one edge joining portion of the first composite element to face one edge joining portion of the second composite element and plastic welding the one edge joining portion of the first composite element to the one edge joining portion of the second composite element.

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 2

plastic welding the one edge joining portion of the first composite element to the one edge joining portion of the second composite element

Methodology Applied
Scientific EffectPlastic welding: Welding

Data Source

PatentEP4342659B1Joining composite elements of wind turbine blades
Publication Date: 2025.11.26 LM WIND POWER AS
  • EP4342659B1 patent drawingFigure 1
  • EP4342659B1 patent drawingFigure 2~3
  • EP4342659B1 patent drawingFigure 4~5C

AI summary

A method for joining a first composite element (100) and a second composite element (200) of a wind turbine blade comprises positioning one edge joining portion (120) of the first composite element (100) to face one edge joining portion (220) of the second composite element (200). In addition, the method comprises plastic welding the one edge joining portion of the first composite element to the one edge joining portion of the second composite element. The edge joining portions (120, 220) are thermoplastic. Meanwhile, main portions (110, 210) of the first and second composite elements may be thermoplastic, or thermoset. In some cases, a shaped connector (160) containing thermoplastic and having the same shape as the void is between first and second composite elements (100, 200) when plastic welding them together. In some cases, the composite elements (100, 200) may comprise a core.