After Gutenberg

Azure Dynamics has placed their electric power trains into delivery vans, such as all-electric ones made in the UK by Smith Electric — precursors to Modec of London (Auroooh). Azure also has experimented with combined battery / capacitor energy storage.

As previously noted, developers are experimenting with combinations of energy storage to extend the range of electric vehicles since batteries cannot absorb nearly all the power that is available from regenerative braking / suspension. The chemical reaction in a battery is much too slow; more than 50% of this energy is wasted.

Several times in the past this blog has noted the use of power-type super capacitors. Azure Dynamics is perhaps the best example; they have built delivery vans with electric drives that included super capacitors. With the decreasing size of such energy storage, there even has been a “proof-of-concept” car. But, such an approach, sending “regen” from brakes and suspension into the “power-rich”,ultra capacitor module, which then gets depleted before any additional charge is drawn from the battery module, is not yet affordable.

A commentator to Yahoo Groups, the electric-vehicles-for-sale forum, recently call attention to a 2005 Physics News Update about a different approach to fabrication of ultra capacitors. The UCLA author indicates the process uses a simple dielectric layer of lithium fluoride sandwiched between Au, Cu, or Al electrodes. Thus, no electrolyte is necessary, which affords better device applications.

This blog recently noted development of thin-film capacitor materials with higher energy storage. The increased capacity was the result of uniform dispersal of nano-size particles in as high a density as possible throughout a polymer matrix.

This was after noting research led by Professor Palusinski. University of Arizona researchers have constructed ultra capacitors using commercially available porous membranes with a pore diameter ranging from 15 nanometers to 1 micron and a hole density of 10 million to 100 trillion pores per square centimeter. They then fill the pores with a conductive metal. The resultant “conductive honeycomb” has a much larger surface area and ability to store electricity than a conductor surface equal to the membrane surface.

Both LTC and Altairnano want to be known for their safe, lithium traction batteries. A battery management system is fundamental to safe operation, particularly when charging the battery pack, either from the Grid or regenerative braking / suspension. Excellent design in power electronics is needed to match the performance of the high density, high output, energy storage to ensure high reliability, long-life, and safety. This is especially true with a combined approach when there are additional DC-DC power electronics to integrate two, different, power supplies.

This blog also mentioned another example of progress toward hybrid energy storage. Michael Graetzel and colleagues at the Swiss Federal Institute of Technology are researching ways to modify the molecular charge transport layer in lithium-ion battery cathodes. Since advanced lithium batteries with improved electrodes already are in production, there exists a fast track for further improvements leading to better performing traction batteries.