According to a new study jointly conducted by the Aluminum Association Inc, and Ricardo a technical research and consultant firm for automotive industries, the use of aluminum in plug-ins, hybrids, and full EVs could reduce vehicle costs by $3,000.
The study shows that the use of aluminum frame and suspension components rather than steel can reduce the weight of a vehicle by 10%. This weight reduction would reduce the load on the batteries powering these vehicles and therefore, automakers could downsize battery packs netting a reduced cost of approximately $3,000.
The study was released at the Business of Plugging In conference held in Detroit this week. Highlights of the study are listed below.
- The driving range of the vehicles could be improved approximately equal to the mass saved. Reduce the mass of the vehicle 20 percent, go 20 percent father. One example vehicle had the range extended from 80 to 97 miles.
- The heaviest vehicle in the study, at 1,822 kg, consumed about 300 Wh/mi, while the lightest at 627 kg consumed about 146 Wh/mi.
- Regenerative braking could recover about 65 percent of the energy associated with the vehicle’s momentum irrespective of the vehicle weight. But this is only about 15-20 percent of the total energy expended.
- For the lightest vehicle, about 44 percent of the energy is lost to powertrain inefficiencies, with 33 percent of the energy used to overcome air resistance, and only 24 percent is used to move the vehicle.
- As with conventional vehicles, the lighter vehicles have faster accelerations.
According to Micheal Bull, Director of Automotive Technology for Novelis, "As automakers gear up for a new generation of plug-in electric vehicles, the high cost of battery power remains a barrier. What this new report shows is that by upgrading from traditional steel to an advanced aluminum body structure, the vehicle’s stored energy requirements can be cut by about 10 percent, which could save up to $3,000 per vehicle since less power and energy is required to move the lighter vehicle.”
All of the highlights of the study as well as the statements made by Bull ignore one important fact. Aluminum is significantly more expensive in vehicle applications than steel.
This negates some of the savings potential, but does not undercut the research. Lighter vehicles less power, have a longer range or better efficiency, and accelerate better. This formula applies to traditional vehicles as well as the plug-in variety.
Source: The Aluminum Association Inc. Press Release
Detroit, October 20, 2009 – Opting for high-strength, low-weight aluminum over heavier steel structures for plug-in electric and hybrid vehicles can cut vehicle price overall by reducing the battery energy requirements and the associated costs, according to a new study released today at the Center for Automotive Research’s (CAR) Business of Plugging In conference. The study was jointly conducted by The Aluminum Association, Inc. with Ricardo, a leading technical research and strategic consultancy to the world's automotive, transport and energy industries.
Michael Bull, Director of Automotive Technology for Novelis, Inc., represented the Aluminum Association at the conference and participated in a panel discussion on future automotive changes associated with all electric vehicles.
“As automakers gear up for a new generation of plug-in electric vehicles, the high cost of battery power remains a barrier,” said Bull. “What this new report shows is that by upgrading from traditional steel to an advanced aluminum body structure, the vehicle’s stored energy requirements can be cut by about 10 percent, which could save up to $3,000 per vehicle since less power and energy is required to move the lighter vehicle.”
“Plug-in and hybrid electric cars contain precious little, and quite expensive, ‘fuel’ in the form of batteries,” added Bull. “Therefore, every effort must be made to utilize this stored energy to the highest possible efficiency. The solution lies in lowering the vehicle’s weight with aluminum as part of a holistic approach to also include advanced powertrains and batteries, enhanced thermal management, improved aerodynamics, and reduced rolling resistance.”
Highlights from the Ricardo electric vehicle study, for the federal test procedure (FTP75) drive cycle, include:
- The driving range of the vehicles could be improved approximately equal to the mass saved. Reduce the mass of the vehicle 20 percent, go 20 percent father. One example vehicle had the range extended from 80 to 97 miles.
- The heaviest vehicle in the study, at 1,822 kg, consumed about 300 Wh/mi, while the lightest at 627 kg consumed about 146 Wh/mi.
- Regenerative braking could recover about 65 percent of the energy associated with the vehicle’s momentum irrespective of the vehicle weight. But this is only about 15-20 percent of the total energy expended.
- For the lightest vehicle, about 44 percent of the energy is lost to powertrain inefficiencies, with 33 percent of the energy used to overcome air resistance, and only 24 percent is used to move the vehicle.
- As with conventional vehicles, the lighter vehicles have faster accelerations.
The purpose of the Ricardo study was to evaluate the impact of vehicle weight reductions on electric vehicle performance, range and battery size. The majority of the vehicle simulations were done using the FTP75 drive cycle with a few highway drive cycles. In general, the relationships between vehicle mass, battery weight and energy, and range are linear up to the maximum range studied of 80 miles. At this range, the battery weight doesn’t grow enough to start a significant “weight spiral.”
The study also examined the role of vehicle mass on regenerative braking; specifically the question of whether strong regenerative braking might lessen the impact of weight reduction. This turns out not to be the case. All vehicles studied could recoup about 65 percent of energy associated with moving the vehicle. But the energy balance for each vehicle changes. As the vehicle gets lighter, less energy is required to move it, while the aerodynamic losses remain constant. For the lightest vehicle the aerodynamic losses are higher than the energy to accelerate the vehicle.
Real world designs support the fact that lightweight structures are a significant enabler for these vehicle types. Examples include Tesla Motors’s Roadster, or upcoming midsized platform, Fisker Automotive’s luxury vehicle and Bright Automotive’s van. All are all using lightweight aluminum platforms for their vehicles.
“Many of the current hybrid vehicles are progressively adding lower weight components to improve the overall vehicle performance. When it comes to making electric vehicles more affordable and efficient, aluminum is proven to get you there with no compromises,” said Bull.
For a summary of the Ricardo study, or general information on the advantages of aluminum for transportation applications, visit www.autoaluminum.org. For a copy of the full study, or to arrange media interviews on the subject, please contact Kristin Tyll at 248-824-8200 or [email protected].
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About the Aluminum Association
Through its Aluminum Transportation Group, the Aluminum Association communicates the benefits of aluminum in ground transportation applications to help accelerate its penetration through research programs and related outreach activities. The ATG’s mission is to serve member companies and act as a central resource for the automotive and commercial vehicle industries on aluminum issues. Member of the ATG include: Alcoa Inc., Novelis Inc., Alcan Inc, Aluminum Precision Products Inc., Kaiser Aluminum Corporation and Sapa Group.
About Ricardo
Ricardo is a leading provider of technology, product innovation, engineering solutions and strategic consulting to the world's automotive, transport and energy industries. Combining business, product and process strategy with fundamental technical research and the implementation of large-scale new product development programs, Ricardo is able to take on the greatest challenges including business strategy and restructuring, process re-engineering, product design, development, engineering, testing and systems integration. More information is available at www.ricardo.com.
