Research On Mechanical Properties Of Large Spiral Spring For Mechanical Elastic Energy Storage

Energy storage technology is one of the cutting-edge technology to solve lots of problems of modern power system, and is the indispensable key technology to build a smart grid, and support of new energy’s sustainable development. In this paper, a new type of mechanical elastic energy storage technology is proposed with the large spiral spring as key component for energy storage. The overall design scheme of mechanical elastic energy storage system is put forward. The research on mechanical properties of large spiral spring as the key part of the energy storage system. The main work of the paper are as follows:(1)This paper discusses the advantages and disadvantages of various energy storage technologies, puts forward a new type of mechanical elastic energy storage technology with large spiral spring as the energy storage component, and expounds the working principle of this energy storage technology, and the calculation methods of the general spiral spring.(2)This paper proposes the overall design scheme of mechanical elastic energy storage system, and analyzes the working principle of the system and the principle of determining key components. The system is divided into two package such as spiral spring energy storage system and electrical control system. The structure of the spiral spring energy storage box in spiral spring energy storage system is discussed, and the choice and control methods of the motor and inverter in the electrical control system is analyzed.(3) According to the shape change of the spiral spring before and in the process of energy storage, the form iterative method is declared. With this method, the Nonlinear mechanics characteristics of spiral spring is analyzed. Before storage, spiral spring’states are divided into the free state on the outside of the spiral spring box and the initial state inside. The form of free state corresponds to the logarithmic spiral, and the forms of initial state correspond to the Archimedes helix and logarithmic spiral. The spiral spring bending moment distribution is calculated with the change of the curvature. In the energy storage process, by analyzing the character of the three forms’ reciprocal transformation, the rule of the spiral spring form change and the relation of bending moment distribution and work angles are analyzed. Taking the spiral spring as a special rotating machinery, the he form iterative method for the spiral spring’s moment of inertia is proposed, by which the change rule of the moment of inertia is get in the energy storage process.(4)The balance equation, geometric equation and physical equation of the spiral spring are deduced in the state of energy storage. Establishing finite element numerical analysis model of the spiral spring, the stress distribution of spring in working status is found. By the stability analysis and modal analysis of the spiral spring, the instability critical bending moment and the frequency and vibration mode of the spiral spring is obtained.(5)The calculation formula is deduced on the energy storage’s quantity and density of spiral spring. The affecting factors of the spiral spring energy storage’s quantity and density are analyzed. By calculating the energy storage’s quantity and density of three kinds of material, it’s found that the material elastic modulus and tensile strength impact the energy storage’s quantity and density. A method of improving the spiral spring energy storage density is declared by changing the structure of the spiral spring section. The structure of the special section of spring is designed, and the energy storage density are calculated comparing with the rectangular section of spring, and the change of the stress and deform of different section of spiral spring are analyzed with maximum torque. The results show the proposed method is available.(6)The experiment prototype of the mechanical elastic energy storage system is built. The Symmetric spiral spring energy storage box is designed and manufactured, and the related electrical equipment and the test system is equipped. After setting experimental parameters, the process of energy storage and release for generating is accomplished with the experiment data. The results of experiment show that the design scheme of mechanical elastic energy storage system is reasonable and mechanical characteristics analysis results of the spiral spring is correct.