Flat Copper Winding for High Fill Factor Energy Converters

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Solution Overview

Problem

Existing methods for producing coil windings in energy converters, such as electromagnetic actuators and rotating electrical machines, face inefficiencies due to low copper fill factors with round enamelled copper wire, which can be improved but at high cost and complexity with cast coils.

Innovation Solution

A method using a copper strip with a rectangular cross-section, processed through stamping, laser cutting, or water jet cutting to create a repeating pattern, allowing for a high copper fill factor with simpler and cheaper manufacturing, followed by annealing and insulating coating to restore conductivity and isolate edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If round enamelled copper wire is used for coil windings, then the manufacturing process is simple, but the copper fill factor is low (40-55%)

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcopper fill factor
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The patent transitions from using round copper wire (one-dimensional circular cross-section) to copper strip with rectangular cross-section (two-dimensional rectangular cross-section). This dimensional change allows the copper to fill the winding space more efficiently, achieving a copper fill factor of up to 70% while maintaining manufacturing simplicity through standard strip processing techniques.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If cast coils with rectangular cross-section are used, then the copper fill factor increases to approx. 70%, but the manufacturing process becomes time-consuming and cost-intensive

Engineering Contradiction:
Improvecopper fill factorVSAvoidmanufacturing complexity and cost
Core Design Contradiction:
Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent changes the cross-sectional parameters of the copper conductor from circular to rectangular, and introduces a repeating pattern with specific geometric parameters (rectangular cutouts) in the copper strip. This parameter optimization allows achieving high copper fill factor (up to 70%) through simpler and more cost-effective manufacturing processes like stamping, compared to traditional cast coil methods.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the complex casting process with simpler mechanical processing methods such as stamping, laser cutting, or water jet cutting to create the repeating pattern in the copper strip. This substitution significantly reduces manufacturing time and cost while achieving the same high copper fill factor.

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

3Ease of manufacture

If copper strip is cut or stamped to create repeating pattern, then manufacturing is simpler and cheaper, but edge isolation is required to prevent electrical shorts

Engineering Contradiction:
Improvemanufacturing simplicity and costVSAvoidedge isolation requirement
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent applies an electrically insulating coating to the copper strip before forming the repeating pattern. This coating automatically provides electrical isolation at the cut edges and surfaces, eliminating the need for additional edge treatment steps. The insulating coating serves multiple functions: electrical isolation, oxidation protection, and manufacturing facilitation.

Inventive Principle:
Principle #25Self-service

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 enables a high copper fill factor with simpler and more cost-effective manufacturing processes, improving the efficiency of energy converters by increasing the copper fill factor from 40-55% to up to 70% while maintaining electrical conductivity and isolating edges.

Implementation Method 1

the spiral body is annealed after cold working. Sufficient electrical conductivity can be restored by the annealing treatment.

Methodology Applied
Scientific EffectAnnealing: Annealing

Implementation Method 2

the spiral body is coated with an electrically insulating material after the annealing treatment. As a result, the punched or cut edges can advantageously also be isolated in the manufacturing process.

Methodology Applied
Scientific EffectCoating: Coatings

Data Source

PatentEP2845208B1Flat copper winding for generating magnetic fields in electrical energy converters with high bulk factors
Publication Date: 2020.01.22 ROBERT BOSCH GMBH
  • EP2845208B1 patent drawingFigure 1~2
  • EP2845208B1 patent drawingFigure 3
  • EP2845208B1 patent drawingFigure 4

AI summary

The invention relates to a method for producing a flat copper winding (1). The invention further relates to an energy converter produced according to said method.