In a project co-funded by the US Department of Energy and managed by Ecotality North America, the Advanced Lead Acid Battery Consortium (ALABC) has demonstrated the durability of lead-carbon batteries in the high-rate, partial state-of-charge operation of a hybrid electric vehicle. A Honda Civic hybrid retrofitted with lead-carbon UltraBattery modules (earlier post) (provided by East Penn Manufacturing) has recorded more than 100,000 miles (161,000 km) of courier duty in the local area of Phoenix, AZ.
The HEV demonstrator, which was first retrofitted and put into fleet duty by Ecotality in November 2011, achieved the benchmark—and continues to run smoothly—in the varying temperatures and elevations of the Phoenix area in just under two-years of operation with no significant loss in battery capacity. The hybrid has also achieved comparable MPG performance with that of the same model powered by Nickel-Metal Hydride (NiMH) batteries but at a significantly lower cost, ALABC said.
The UltraBattery Retrofit Project DP1.8 and Carbon Enriched Project C3 were established to demonstrate the suitability of advanced lead battery technology in hybrid electrical vehicles (HEVs). The fleet testing is the last task in the Ecotality/DOE work program.
In the C3 Project, valve-release, lead-acid batteries containing high levels of carbon in the negative electrode are being designed, manufactured, and evaluated under laboratory-simulated test cycles. In order to streamline both research projects, the battery evaluation component of the C3 Project was combined with the retrofit project. Researchers at the DOE’s Idaho National Lab issued a report on the development and testing of the UltraBattery hybrid in August 2012.
An important objective of the project has been to benchmark the performance of the UltraBatteries manufactured by both Furukawa Battery Co., Ltd., Japan (Furakawa) and East Penn Manufacturing Co., Inc. (East Penn). Accordingly, UltraBattery packs from both Furakawa and East Penn have been characterized under a range of conditions. Resistance measurements and capacity tests at various rates show that both battery types are very similar in performance. Both technologies, as well as a standard lead-acid module (included for baseline data), were evaluated under a simple HEV screening test. Both Furakawa and East Penn UltraBattery packs operated for over 32,000 HEV cycles, with minimal loss in performance; whereas the standard lead-acid unit experienced significant degradation after only 6,273 cycles. The high-carbon, ALABC battery manufactured in Project C3 also was tested under the advanced HEV schedule. Its performance was significantly better than the standard lead-acid unit, but was still inferior compared with the UltraBattery. The batteries supplied by Exide as part of the C3 Project performed well under the HEV screening test, especially at high temperatures. The results suggest that higher operating temperatures may improve the performance of lead-acid-based technologies operated under HEV conditions—it is recommended that life studies be conducted on these technologies under such conditions.—“Development and Testing of an UltraBattery - Equipped Honda Civic”
According to the DOE report, as of the end of August 2012, the vehicle had accumulated more than 60,000 miles and had experienced a wide range of driving conditions. The battery capacity was 7.54 Ah (at a C1 rate) after 51,000 miles driven, which is a very minimal capacity loss when comparing an average 7.55 Ah for the new modules.
The vehicle delivers an average of a 44-mpg (5.3 l/100km) fuel economy when driving under mild temperature and in reasonably flat terrain. This drops to approximately 35 mpg (6.7 l/100km) when the temperature increases and the terrain becomes hillier. The original 2010 Civic Hybrid carried an EPA fuel economy rating of 42 mpg combined (40 city, 45 highway).
The lead-carbon UltraBattery technology was originally developed by Australia’s Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Furukawa Battery of Japan and supplied by East Penn Manufacturing of Lyon Station, PA. This battery design combines a traditional lead-acid battery with a carbon-enhanced supercapacitor in one singular and highly-effective component.
The ALABC tested Furukawa’s UltraBattery modules in 2010 in a Honda Insight demonstrator and also reached the 100,000-mile mark, but the results were achieved on a test track in Millbrook, UK.
When we first achieved 100,000 with the UltraBattery Insight vehicle in Millbrook, we raised several eyebrows, but we realized that automakers wanted to see how the modules would operate in real-world conditions, and preferably in a bigger hybrid electric vehicle with more power demand on the battery. That’s when we approached the US DOE and Ecotality about operating a vehicle in a fleet in and around Phoenix.—Dr. Boris Monahov, program manager
In the funding arrangement with the DOE, ALABC representatives engaged Ecotality North America to retrofit a Honda Civic HEV by replacing its NiMH batteries with UltraBattery modules supplied by East Penn.
Ecotality ran extensive tests on East Penn’s UltraBattery design and was able to reach 167,000 miles in laboratory testing simulating actual vehicle operations. Following the simulation tests, Ecotality engineered the actual conversion of the vehicle and put it into daily route duty in a courier fleet. Today, the demonstration vehicle continues to run on a daily schedule and the batteries are operating better than expected.
East Penn obtained a patent in 2008 to produce the UltraBattery energy storage technology, and it has used UltraBattery modules in its own demonstration hybrid (also based on a Honda Civic HEV). That vehicle undergoes consistent road testing and battery system analysis at East Penn’s manufacturing complex in Lyon Station, PA, and it has already racked up 65,000 miles of real-world duty.
After reaching 50,000 miles, the battery pack of this car showed no performance degradation and the individual battery voltages of the pack actually converged as they aged—suggesting UltraBattery technology can diminish the complexity and expense of other battery technologies and their battery monitoring systems.
East Penn, along with its subsidiary Ecoult, is also evaluating their UltraBattery units as the main power source in a successful smart grid demonstration facility in Lyon Station. This energy storage facility, which was also supported by a grant from the Department of Energy, is the second DOE Smart Grid Demonstration Program to be launched using UltraBattery technology.
The Consortium intends to continue running the hybrid it to see how long the batteries will last. The ALABC will also seek additional research and development projects to not only study the performance of UltraBattery modules and other lead-carbon designs, but also other applications of these batteries in automotive and energy storage capacities.