The US Department of Energy (DOE) released the EV Everywhere Grand Challenge Blueprint, which describes plug-in vehicle (PEV) technology and deployment barriers, and provides an outline for DOE’s technical and deployment goals for electric vehicles to 2022. DOE will pursue these targets in cooperation with a host of public and private partners.
President Obama announced the DOE “Clean Energy Grand Challenge” in March 2012 with the goal of enabling US companies to be the first in the world to produce plug-in electric vehicles (PEVs) that are as affordable and convenient for the average American family as today’s gasoline-powered vehicles within the next 10 years. In September 2012, DOE requested public comment on an EV Everywhere Initial Framing Document. (Earlier post.)
Technical targets in the Blueprint fall into four areas: battery R&D; electric drive system R&D; vehicle lightweighting; and advanced climate control technologies. Some specific goals for 2022 include:
Cutting battery costs from their current $500/kWh to $125/kWh
Eliminating almost 30% of vehicle weight through lightweighting
Reducing the cost of electric drive systems from $30/kW to $8/kW
The targets are “stretch goals” established with consultation with stakeholders across the industry.
When these goals are met, the levelized cost of an all-electric vehicle with a 280-mile range will be comparable to that of an ICE vehicle of similar size. Even before these ambitious goals are met, the levelized cost [purchase cost + operating cost] of most plug-in hybrid electric vehicles—and of all-electric vehicles with shorter ranges (such as 100 miles)—will be comparable to the levelized cost of ICE vehicles of similar size. Although there is little evidence that levelized cost plays an important role in vehicle purchase decisions for most consumers, there is substantial evidence that initial purchase price plays an important role—and meeting these targets will help to reduce the purchase price for plug-in electric vehicles. In light of uncertainty concerning consumer preferences and manufacturer plans for PEVs, DOE is selecting ambitious technical goals for this program.—Blueprint
Batteries. In the near-term (2012-2017), DOE sees an opportunity to more than double the battery pack energy density from 100 Wh/kg to 250 Wh/kg through the use of new high-capacity cathode materials, higher voltage electrolytes, and the use of high capacity silicon or tin- based intermetallic alloys to replace graphite anodes.
Despite current promising advances, DOE cautions that much more R&D will be needed to achieve the performance and lifetime requirements for deployment of these advanced technologies.
For the longer term, (2017-2027) while “beyond Li-ion” battery chemistries such as lithium-sulfur, magnesium-ion, zinc-air, and lithium-air, offer the potential of significantly greater energy densities, breakthrough innovation will be required for these new battery technologies to enter the PEV market, according to DOE.
Electric drive systems. Developing advanced power electronic, electric motor, and traction drive system technologies that will leapfrog current on-the-road technologies with a system-level emphasis to improve fuel efficiency and reduce cost are key to meeting the EV Everywhere Grand Challenge.
Achieving the targets will require R&D in several areas including permanent magnet materials, non-rare earth magnets, advanced capacitors, thermal and electrical packaging, wide bandgap (WBG) semiconductors, and motor laminations.
Cost and performance targets in this technology area include:
Electric motors. Develop new low-cost and highly efficient motor designs, alternative magnetic materials with reduced rare earth content, and improved motor manufacturing methods. Long-term emphasis on non-rare earth motor architectures will reduce motor costs and mitigate rare earth market uncertainties for the original equipment manufacturers and their suppliers.
Power electronics. Develop affordable WBG devices, high- temperature capacitors, advanced packaging, high voltage operation, and new circuit topologies. Designs using WBGs will increase as manufacturing processes enable improved device yield and performance. In addition, this research includes advancements in thermal management such as low cost heat transfer technologies, thermal stress and reliability, and thermal systems integration.
Traction drive system. Integrate power electronic and motor technologies along with traction drive control strategies, innovative integrated system designs, and thermal management.
On-board chargers. Reduce the cost for on-board chargers, followed by overcoming packaging and thermal limitations.
Overall, DOE is seeking a 4x cost reduction, a 35% size reduction, a 40% weight reduction, and a 40% loss reduction in the electric drive system from 2012 to 2022. That would take a 55 kW system cost of $1,650 down to $440 and increase power density from 1.1 kW/kg to 1.4 kW/kg.
Vehicle lightweighting. Reducing the weight of a PEV can extend the electric range, reduce the size and cost of the battery, or support a combination of the two. By 2022, DOE is seeking to reduce weight by 35% for the body structure, 25% for the chassis and suspension, and 5% for the interior.
To achieve this, lightweight metals and composites must be an attractive choice by meeting both cost and structural requirements. Materials properties related to mechanical behavior, crash response, and durability of vehicle structures must be improved. Techniques for predicting material behavior must be integrated with design methods to enable reduced cost, such as by minimizing input material quantities or decreasing cycle time.
Lightweight material systems include carbon fiber composites, magnesium alloys, advanced high strength steel, and aluminum alloys; and techniques to join combinations of these materials in a cost effective manner are also critical.
Climate control technologies. Using less energy in PEVs to achieve comfortable climate control will allow for a smaller, less expensive battery, and thus contribute to lowering the cost of PEVs. EV Everywhere will focus on the following specific research areas:
Energy load reduction and energy management strategies can minimize energy consumption by reducing the thermal loads that the systems must address. Advanced windows and glazing, surface paints, advanced insulation, thermal mass reduction, and ventilation and seating technologies can better control heat transfer between the passenger cabin and the environment, minimizing the thermal loads that the Heating, Ventilation and Air-Conditioning (HVAC) systems must address to ensure passenger comfort.
Advanced HVAC equipment, such as advanced heat pumps or novel heating/cooling subsystems, can reduce the auxiliary loads. Innovative heating and cooling concepts to achieve passenger comfort, such as infrared and thermoelectric devices and phase change materials, can also reduce energy requirements.
Cabin pre-conditioning while the vehicle is connected to the grid can reduce the amount of energy needed from the battery upon initial vehicle operation to either pull-down (hot conditions) or raise (cold conditions) the temperature in the cabin. Another approach to cabin pre-conditioning is to utilize waste heat generated within the battery and/or charging circuit during charging.