E-flex Aerodynamics and Battery Mass

In an interview with Denise Grey, the Autoblog Green interviewer mentions a recent tour of the E-flex Design Studio in Warren [Michigan] with Bob Boniface. During that tour, discussion turned to the aerodynamics of the Volt.

The Volvo ReCharge Concept is a plug-in series hybrid with advanced lithium batteries that give it a range of over 60 all-electric miles. Volvo engineers claim 66 per cent lower CO2 emissions than the best hybrids available today, read the Toyota Synergy Drive. Doing the right thing — Big Electric - Little ICE, especially when it is a flex-fuel ICE — is the carrot, Bugs. “Hey, I have reduced my CO2 emissions to less than 120 grams per kilometer while getting 160 kilometers to the gallon.”

The ABG interviewer learned that, even at lower speeds, i.e., city speeds, “aerodynamics had much more effect on the range of the vehicle than mass.”

They [the E-flex designers] could increase the mass a little bit with bigger battery or just heavier components, and have a less of an impact than the aerodynamics. Presumably, that is because by not burning off kinetic energy through aerodynamic drag; you can recapture that as regenerative braking.

Note: Since orders now can be placed in California for an Aptera, one might suspect a greater emphasis on aerodynamics has returned.

This blog previously has noted the important correlation between aerodynamics and fuel efficiency at high speeds. One developer found that installing an aeroshell over the truck bed, plus other aerodynamic improvements, e.g., side skirts, frontal air dam, grille cover, underbelly, covered rear wheel wells, reduced the Cd (Drag co-efficient) of the truck an estimated 0.25 (same as a Honda Insight). He saw highway fuel economy jump from 25 mpg to 33 mpg at 70 mph. The same principle applies if considering mega-joules rather than gallons of gasoline, and would seem to more critical at lower speeds than previously thought.

The size of the generator set, a.k.a. “genset”, a.k.a., range extender, depends upon a number of factors. The vehicle coefficient of drag is a critical factor, i.e., a good rule of thumb is sizing the genset to overcome resistance from the aerodynamic of the vehicle. For its day, the GM EV1 featured superb aerodynamics.

The relevance to the ABG interview with the director of Hybrid Vehicle Energy Storage Systems for General Motors, was whether the advanced lithium batteries now being tested allow for rapid recharging. Some manufacturers of advanced lithium batteries tout the ability of their products to capture energy quickly. Such capability means that more kinetic energy can be reclaimed.

Dr. Grey indicated that her lab currently was not testing this feature. Given the high cost of advanced lithium batteries and their shorter life span compared to ultra capacitors, there still would seem to be a business case for the latter to provide rapid energy storage, if it can be done in a cost effective manner.

Tyler Hamilton1, an energy reporter and business columnist for the Toronto Star, Canada’s largest daily newspaper, who previously has reported on EEStor development, now tells us that EEStor has partnered with Lockheed Martin. While he puts a good spin on this news, it is discouraging to EV enthusiasts looking for a cost effective means of providing rapid charging. War is big business; there is no way that we can compete with the deep pockets of the military and homeland security.

Defense contractors effectively will lock in this potentially disruptive technology. According to Glenn Miller, vice-president of technical operations and applied research at Lockheed Martin Missiles and Fire Control, “The EEStor energy storage technology provides potential solutions for the demanding requirements for energy in military and homeland defense applications.”

“It’s later than we all expected,” writes the Toronto Star Reporter, “but ‘late 2008? at least gives us something new to measure the company by. Besides, it appears the late 2008 applies just to Lockheed.” According to one source close to EEStor. ZENN Motors “expects delivery before Lockheed Martin as the existing plant is exclusively for ZENN production.” I would liken it to waiting for Godot to arrive in Chevrolet Volt.Similar Posts:

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1EEStor partners with Lockheed Martin

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