Energy Storage in Carbon Nanotube-based Springs

Applications

Energy storage in carbon nanotube-based springs can be used for portable power supplies that need both high power density and high energy density. Companies devoted to manufacturing energy storage devices, electronic devices, electronic or hybrid vehicles, and battery manufacturing would benefit from this invention. 

Problem Addressed

The deformation of elastic springs is one of the oldest and best-known forms of energy storage. The advantages of mechanical springs over other forms of energy storage include high reliability, durability, and efficiency. Although mechanical springs are typically used to power clocks and wrist watches, new advances have led to mechanical springs as a means of powering electronic devices such as vehicles and radios. However, mechanical springs exhibit low energy storage density. Energy storage devices based on the mechanical deformation of Carbon Nano Tubes (CNT) are in principle capable of much higher energy density than any known chemical battery. Moreover, CNTs also have the potential to be more efficient and to have longer lifetimes than chemical batteries. Therefore, this technology will be able to store greater amounts of energy and subsequently use that energy for practical purposes such as powering machinery or electronic devices. 

Technology

This invention uses the mechanical deformation of nanotubes or highly ordered assemblies of molecules as a means of storing energy. The deformation includes stretching, bending and twisting. The storage of macroscopically significant amounts of energy may be achieved by assembling a large number of nanotubes and deforming them in parallel. In one example, the assembly of nanotubes is stressed by screws at both ends while attached to a mechanical cam. To store energy, the cam is driven to rotate by connected piezoelectric blocks; and the reverse process releases the stored energy. The nanotubes can be made of carbon, boron, or nitrogen. The energy stored in such “super-springs” can be recovered for subsequent use either in the form of mechanical energy or in the form of electricity.

Advantages

  • High energy storage density 
  • High power density
  • Ability to drive mechanical systems directly without first converting the energy from electricity