Stacked Flywheel Rotor Segmentation for Energy Storage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing energy storage systems, including flywheel systems, face limitations in size, cost, storage efficiency, and material constraints that restrict the thickness and energy storage capacity of flywheel rotors, necessitating the development of innovative solutions to enhance kinetic energy storage while reducing costs and logistical challenges.
Innovation Solution
A high-strength metal alloy flywheel rotor with specific material characteristics, such as yield strength and fracture toughness, and a unique design featuring a fishtail shape and interconnected sub-rotors, which allows for increased diameter and reduced thickness, enabling greater energy storage capacity and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If rotor thickness is increased to store more kinetic energy, then energy storage capacity is improved, but material constraints (through-hardening depth) limit the maximum thickness to 8-14 inches for low-alloy steel
Solution Approach 1:
The rotor is divided into multiple segments or layers with varying material compositions. Inner layers use high-alloy steel suitable for thick sections, while outer layers use lower-alloy steel optimized for surface hardness. This segmentation allows each layer to be manufactured within its material's optimal thickness range while collectively achieving greater total rotor mass and energy storage capacity.
2Quantity of substance
If rotor diameter is scaled up to increase energy storage capacity, then kinetic energy storage is improved, but capital investment in tooling and manufacturing complexity increases substantially
Solution Approach 1:
The large-diameter rotor is constructed by assembling multiple smaller forged or cast segments around a central hub. These segments can be manufactured using standard-sized tooling, avoiding the need for expensive custom tooling for large-diameter forgings. The segments are then joined using welding, bolting, or interference fit techniques to form the complete large-diameter rotor structure.
Solution Approach 2:
Multiple separately manufactured rotor components (segments, hubs, rims) are combined to form the complete rotor assembly. This merging approach allows each component to be optimized and manufactured independently using appropriate processes and tooling, then assembled into the final large-diameter structure, reducing overall manufacturing complexity and tooling investment.
3Quantity of substance
If rotor diameter is increased to store more energy, then energy storage capacity is improved, but shipping and handling logistics become more challenging
Solution Approach 1:
The rotor is designed as an assembly of separable segments that can be shipped individually in standard cargo containers or on conventional transport equipment. After delivery to the installation site, the segments are assembled on-site to form the complete large-diameter rotor. This eliminates the need for specialized oversized transport equipment and reduces shipping costs and logistical complexity.
4Quantity of substance
If higher strength materials are used to increase rotor thickness, then energy storage capacity is improved, but material cost and manufacturing complexity increase
Solution Approach 1:
Different regions of the rotor use different material compositions optimized for their specific functional requirements. The inner core uses high-strength, high-alloy steel to withstand the highest centrifugal stresses and enable greater thickness. The outer regions use lower-alloy steel with sufficient strength for their position, reducing material cost while maintaining overall rotor integrity and energy storage capacity.
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
The solution provides improved kinetic energy storage capacity at reduced costs, with the ability to manufacture larger rotors that can store tens to hundreds of kWh of energy, while minimizing stress and logistical challenges associated with large diameters and constrained thickness.
Implementation Method 1
the rotor material's yield strength, fracture toughness, maximal intrinsic defect size, cyclic fatigue characteristics
Implementation Method 2
the rotor material's yield strength, fracture toughness, maximal intrinsic defect size, cyclic fatigue characteristics
Implementation Method 3
A flywheel is one type of energy storage system that stores energy as rotational kinetic energy
Data Source
AI summary
Embodiments of the subject invention are directed to a flywheel rotor that includes two or more sub-rotors stacked one on top of another, in which each sub-rotor is rotationally symmetric and disk shaped, where the axial centers of each sub-rotor in the stack are rotationally aligned, and each sub-rotor has an upper and a lower journal that extends outward from the origin of the center section of the primary rotational mass of the sub-rotor. Each pair of adjacent sub-rotors in the stack has a lower journal of an upper sub-rotor that is disposed above an upper journal of a lower sub-rotor. Also, there is a joining mechanism between each pair of adjacent sub-rotors that fixedly connects the lower journal of the upper sub-rotor to the upper journal of the lower sub-rotor.