Flywheel Energy Storage: in Automotive Engineering

Description

Storing energy is one of the most important challenges of our time. Energy storage systems are not only essential for switching to renewable energy sources, but also for all mobile applications. Electro-mechanical flywheel energy storage systems (FESS) can be used in hybrid vehicles as an alternative to chemical batteries or capacitors and have enormous development potential. In the first part of the book, the Supersystem Analysis, FESS is placed in a global context using a holistic approach. External influences such as the vehicle, driver and operating strategy, including socio-psychological aspects, are analyzed with regard to their interaction with the memory. From this, optimal application scenarios are derived and the development goals relevant for market success are defined. In the second part, the consideration of the subsystem, those critical components in the FESS are identified which are responsible for the achievement of the technical target properties. From the point of view of maximum cost reduction, specific solutions for the design of the key components are presented and their suitability is validated through empirical studies on the housing, bearing and rotor as well as through overall prototypes.This book is a translation of the original German 1st edition Schwungradspeicher in der Fahrzeugtechnik by Armin Buchroithner published by Springer Fachmedien Wiesbaden GmbH, part of Springer Nature in 2019.  Formula Symbols Acknowledgments Summary Contents Abbreviations 1: Introduction 1.1 Structure of this Book 1.2 Motivation for a Holistic Assessment of the System ``Energy Storage-Vehicle-Environment´´ 1.3 Initial Situation: Europe in the Energy Revolution 1.4 The Role of the Transport Sector 1.5 The Future of Transportation References 2: Complexity, Importance, and Overall System Dependency of the Vehicle Operating Strategy 2.1 A Holistic View: Vehicle, Driver, and Environment 2.2 Subsystem of Flywheel Energy Storage 2.2.1 Fundamentals of Kinetic Energy Storage 2.2.2 Differentiation According to Transmission of the Stored Energy 2.2.2.1 Purely Mechanical FESS 2.2.2.2 Electromechanical FESS 2.2.3 System Components of a FESS 2.3 State of the Art in the Field of Flywheel Energy Storage Systems 2.3.1 Existing Systems: Stationary FESS 2.3.2 Mobile Flywheel Energy Storage Systems for Vehicles References 3: Supersystem of Mobile Flywheel Energy Storage 3.1 Vehicle and Vehicle Topology 3.2 Features of the Primary Drive 3.3 Properties of Mobile Energy Storage Devices 3.4 Geography, Infrastructure, and Intended Use of the Vehicle 3.4.1 Geography and Infrastructure 3.4.2 Intended Use of the Vehicle 3.5 Driver and Energy Psychology References 4: Interaction Between Subsystem and Supersystem of Mobile Flywheel Energy Storage 4.1 Examples of Direct Influence on the Super- and Subsystem of FESS 4.2 Optimization of the Supersystem 4.2.1 Influence of the Driving Cycle on the FESS 4.2.2 Energy Requirements of the Vehicle 4.2.2.1 Theoretically Recoverable Energy 4.2.2.2 Effective Speed Range for Regenerative Braking 4.2.3 Profitability of a FESS in a Vehicle References 5: Optimizing the Supersystem of Mobile Energy Storage 5.1 Emotion Versus Ratio: Passenger Car Versus Commercial Vehicle 5.2 Aspects of the Supersystem of Public Transport and Commercial Vehicles 5.2.1 Energy Efficiency of Commercial Vehicles 5.2.1.1 Simulation of Driving Cycles and Operating Strategies in Public Transport 5.2.2 Operating Conditions for Hybrid Propulsion Systems and Energy Storage Requirements 5.3 Individual Transport and Personal Cars 5.3.1 Aspects of the Supersystem ``Personal Car´´ 5.3.2 Driver and Psychology 5.3.3 Target Characteristics of Mobile Flywheel Energy Storage Devices 5.3.3.1 Economic Consideration 5.4 Energetic Threshold Specifications 5.4.1 Determination of Energetic Threshold Specifications for FESS 5.5 Relevant Findings of the System Analysis 5.5.1 Summary: Optimization of the Supersystem of a FESS 5.5.2 General, Desirable FESS Improvements References 6: Subsystem Optimization 6.1 Deviation of Desired from Actual Characteristics 6.1.1 Analysis of the Cost and Weight of the System Components of Two FESS Prototypes 6.2 Internal System Interdependencies: Interactions Between Critical Components 6.2.1 Categorization of the Interdependencies 6.2.2 Critical Interdependencies in the FESS Subsystem 6.2.3 Identification of Critical Components 6.2.3.1 The Bearing System as Technical Enabler 6.3 Results: Critical Components in FESS References 7: Rotors for Mobile Flywheel Energy Storage 7.1 Essential Physical Relationships of FESS Rotor Design 7.2 Analysis of Existing Systems/State of the Art 7.2.1 Composite Flywheels 7.2.1.1 Advantages of Composite Flywheel Rotors 7.2.1.2 Disadvantages of Composite Rotors 7.2.2 Steel Flywheels 7.2.2.1 Development Goals for Steel Rotors 7.3 Requirements Derived from the Supersystem Analysis 7.4 Solution Approach/Case Study: CMO Rotor 7.4.1 System Description Clean Motion Offensive Flywheel 7.4.2 The CMO Rotor Concept 7.4.2.1 Balancing of the CMO Rotor 7.4.2.2 Burst Behavior of the CMO Rotor 7.5 Solution Approach/Case Study: FIMD Flywheel 7.5.1 Structure of the FIMD Rotor 7.5.1.1 Choice of Material 7.5.1.2 Assembly and Conditioning of the Rotor 7.5.2 Burst Testing the FIMD Rotor 7.5.2.1 Qualitative Postmortem Analysis 7.5.3 Summary of Results: Fully Integrated Multi-Disk Rotor (FIMD) References 8: Flywheel Energy Storage Housing 8.1 Requirements Derived from Supersystem Analysis 8.2 Safety Requirements for Mobile Energy Storage Devices 8.3 Analysis of Existing Systems/State of the Art 8.3.1 Example: Safety Housing for Composite Rotors of Stationary FESS 8.4 Relevant Findings from Past Research Projects 8.4.1 Particle Kinematics 8.5 Practical Design of FESS Housings 8.6 Analytical Calculation Methods for Designing FESS Burst Containments 8.6.1 Calculation According to Lockheed Missiles Company [6] 8.6.2 Calculation According to Giancarlo Genta [7] 8.6.3 Calculation According to NASA [5] 8.7 Application of the Calculation Methods and Comparison of the Results 8.7.1 Summary and Plea for Empirical Burst Containment Studies 8.8 Qualitative Analysis and Overview of Previous Burst Tests 8.9 Empirical Investigation of FESS Burst Containments 8.9.1 Commercially Available Spin Pits and Testing Services 8.9.2 Structure of the Burst Test Bench 8.9.3 Method and Experimental Procedure 8.9.4 Energy Balance 8.9.5 Summary of Previous Findings References 9: Bearings for Flywheel Energy Storage 9.1 Analysis of Existing Systems and State of the Art 9.2 Requirements Derived from the Supersystem Analysis 9.2.1 Determination of Bearing Loads 9.3 Gyroscopic Reaction Forces in Flywheel Energy Storage 9.3.1 The Supersystem of FESS Bearings: Analysis of Environmental Parameters 9.3.2 Influence of FESS-Specific Operating Conditions on Bearing Design 9.4 Complexity and Importance of FESS Bearing Design 9.5 Determination of Gyroscopic Bearing Loads 9.5.1 Step 1: Analytical Estimation 9.5.1.1 Results of the Analytical Assessment 9.5.2 Step 2: Numerical Simulation 9.5.2.1 Load Collective and Peak Values 9.5.2.2 Estimation of Heavy Misuse Bearing Loads 9.5.2.3 Results of the Numeric Simulation 9.5.3 Step 3: Empirical Verification 9.5.3.1 Results of the Empirical Verification 9.5.3.2 Evaluation of the Empirical Verification 9.5.4 Conclusion Regarding Gyroscopic FESS Bearing Loads 9.6 Imbalance Forces in Energy Storage Flywheels 9.6.1 Balancing and Balancing Options of the FIMD Rotor Case Study 9.6.1.1 Problems of Subcritical Rotor Operation 9.6.1.2 Estimation of the Natural Frequency of the FIMD Rotor Bearing System 9.6.1.3 Influence of Bearing Stiffness on the Natural Frequency of the FIMD Rotor System 9.6.1.4 Commissioning and Problems of FIMD Rotor Bearing System 9.6.1.5 Analysis of the FIMD Rotor Bearing System 9.7 Resilient Bearing Seats for Rolling Bearings in FESS 9.7.1 Case Study CMO Flywheel Energy Storage System 9.7.2 Investigation of Alternative Bearing Seat Concepts: Practical Example LESS 9.7.2.1 Increasing Bearing Life Through the Use of Resilient Bearing Seats 9.7.2.2 Summary: Bearing Loads in FESS 9.8 Thermal Properties of FESS Bearings 9.8.1 Test Rig for Determining the Thermal Conductivity of Rolling Bearings References 10: Stationary FESS for Modern Mobility 10.1 Reduction of Torque Loss of FESS Bearings 10.1.1 Bearing Concepts for Stationary Flywheel Energy Storage Systems 10.2 Loads and Friction Losses in Rolling Bearings for FESS Applications 10.2.1 Bearing Loads of Stationary Flywheel Energy Storage Systems 10.2.2 Analytical Determination of Bearing Torque Loss 10.3 Bearing Load Reduction for Energy Storage Flywheels with Roller Bearings 10.3.1 Reduction of Axial Loads 10.3.1.1 Option 1: Attracting Arrangement with Hard Ferrite Ring 10.3.1.2 Option 2: Two Magnets in Repelling Arrangement 10.3.1.3 Option 2b: Repelling Arrangement of Two SmCo Disk Magnets 10.4 Reduction of Radial Bearing Loads 10.4.1 Cast Silicone Bearing Seat 10.4.1.1 Results 10.5 FlyGrid: Flywheel Energy Storage for EV Fast Charging and Grid Integration 10.5.1 Developments in Electric Mobility 10.5.2 Aims of the FlyGrid Project 10.5.3 Core Element Flywheel Energy Storage References 11: Summary and Outlook