New nano foam polymer lithium batteries are relatively compact, light weight and have been designed to allow greater storage of electrical charge than other types of battery. They hold the potential to significantly increase the range of electric vehicles of the future. However, more importantly, this new type of battery can be molded into virtually any conceivable shape (Topix, 29/06/11). This capability naturally leads to the idea of replacing most if not all of the structural elements of a traditional automobile frame by battery elements that have been moulded into the same shapes as the various elements that make up the frame.
The design of the outer package or housing of the battery depends to a certain extent on the components it has to accommodate and the physical protection it has to provide for them. These components are not just the cells, but also protection devices, electronic circuits, interconnections and connectors which must all be specified before the final battery case can be designed. New technological advances has resulted in the miniaturization of most of these components, meaning the there are now few limitations on the shapes that battery systems can be designed.
Low power cells are usually connected together using nickel strips which are welded to the cell terminals or the case. Soldering is not recommended since the soldering process is apt to apply large, uncontrolled amounts of heat to the battery components which may damage the separators or the vents which are normally made of plastic. Modern computer controlled resistance welders allow much more precise control of the welding process, both limiting the amount of heat applied to the battery and localising the heat to a small desired area. Welding also provides a stronger, low resistance joint. The interconnecting strips often have complex shapes and profiles which may be stamped out of flat strip in a progressive die.
The essence of this innovation is therefore to eliminate the need for a "battery pack" in an electric vehicle and to replace it by a frame made up of structural elements that are all component parts of a "distributed battery pack." In essence, the entire vehicle becomes an energy storage unit, and not just the battery pack.