The Hybrid Systems research team at GE Global Research successfully demonstrated a dual battery system on a zero tailpipe emissions hybrid transit bus that pairs a high-energy density sodium battery with a high-power lithium battery.
GE researchers believe a dual system with high power and energy storage capacity could achieve the optimal electric driving range and acceleration requirements at a more practical size scale and cost for larger vehicles.
The research is being done as part of a $13 million research project GE is engaged in with the Federal Transit Administration (FTA) and Northeast Advanced Vehicle Consortium, funded under the National Fuel Cell Bus Program.
Many of the 843,000 buses registered in the U.S. (including most of the 63,000 transit buses and 480,000 school buses) travel less than 100 miles per day. Enabling more of these buses to transition to an all-electric, zero emissions platform would dramatically reduce CO2 emissions and petroleum fuel consumption.
Most types of batteries today come with a trade-off between power and energy storage. For example, lithium batteries, provide a lot of power for acceleration, but are not optimized to store energy for driving range. Sodium batteries are on the opposite side of the spectrum. They store large amounts of energy, but are less optimized for power. GE’s dual battery combines the best attributes of both chemistries into a single system. In the hybrid transit bus demonstration, the lithium battery focused on the high power acceleration and braking, while the sodium battery provided an even electric power flow to extend the bus range. Each type of battery does what it does best.
In addition to optimizing performance, a dual system can reduce the cost of a battery by up to 20% compared to a single battery system for vehicle applications like transit buses and delivery trucks that require significant power and energy storage capacity. The key cost advantage of a dual system is that it provides flexibility to integrate less expensive battery chemistries without having to increase the size of the battery to address a vehicle’s power and energy storage needs. A single battery system would require a more costly scale up in the size of the battery to achieve the same result.
The development of a dual battery system and partnership with the FTA is a key part of GE’s growing hybrid and electric technology portfolio. GE is actively exploring partnership opportunities across the electric vehicle value chain through its Licensing business to commercialize its dual battery technology.
GE also is developing new technologies and products to support the integration of plug-in hybrid electric vehicles (PHEV) and electric vehicles (EV) into the electric grid.
• GE is building a new battery factory in Schenectady, New York, which will commercialize GE’s new Durathon battery with best-in-class sodium technology performance.
• In July, GE announced the launch of WattStationTM, a new electric vehicle charging station that will be commercially available globally in 2011.
• In April, GE signed a Memorandum of Understanding (MOU) with the automaker, Nissan to explore new technologies that will be needed to build a reliable, dynamic smart-charging infrastructure.
• In September, GE established a technology and financing partnership with Better Place to accelerate the global deployment of an electrical vehicle infrastructure through collaboration in four key areas: standards-based technology development, battery financing, joint fleet electrification programs and consumer awareness.
Building on these investments and research activities, GE announced it would purchase 25,000 electric vehicles by 2015 for its own fleet and through its Capital Fleet Services business – the largest-ever single electric vehicle commitment. GE will initially purchase 12,000 GM vehicles, beginning with the Chevrolet Volt in 2011, and will add other vehicles as manufacturers expand their electric vehicle portfolios.
GE’s activities in hybrid and battery technologies, electric vehicle charging and PHEV and EV grid integration are closely aligned with its ecomagination initiative. Ecomagination represents the company’s commitment to deliver new clean products and technologies to market that help solve our toughest environmental challenges. GE has more than 80 eco-certified products, including cutting-edge energy efficient lighting and appliance products, which have met the Initiative’s goal of improving both operational and environmental performance. Recently, the company pledged to double its investment in clean R&D over the next five years from $5 billion to $10 billion.