Electromechanical Energy Storage: The Flywheel

Currently, engineers all over the world are racing to develop zero-emissions vehicles (ZEV) that can supplant today\u27s internal combustion (IC) engine-powered vehicles which waste energy and pollute the air. Their most difficult task is to engineer a drive that combines low or zero pollution with high efficiency, reliability, affordability, and safety. Furthermore, the system must be able to deliver the high torques and accelerations that drivers have come to expect from present vehicles. It is obvious to carmakers that the first company to produce such a drive train will have a significant advantage over competitors. Furthermore, inn the continuing battle for clean air, several governments have adopted legislation forcing carmakers to increase their efforts. For example, California has already enacted a special 2% by 1998 ZEV mandate. This means that at least two percent of the vehicles carmakers sell in 1998 must be zero-emission vehicles. For every car less than 2%, a fine of $5,000 is imposed. To this end, engineers are designing and experimenting with different electric (EV) and hybrid electric vehicle (HEV) drive trains. While EV and HEV designs use energy more efficiently and with less pollution than their IC engine-powered counterparts, they usually lack in performance and/or range. This lack is due primarily to the inefficient and low energy storage systems included in both drive train configurations, in most cases, a stack of electro-chemical (EC) batteries. The EC battery is the least expensive and most readily available option for carmakers but, it is also inefficient, of low energy density, and uses hazardous materials that pose disposal and recycling questions. The thrust of this paper is to introduce the electromechanical battery (EMB) and to demonstrate it as a viable alternative to the shortcomings of current energy storage technology