After seven years of secretive development, New Castle, Pennsylvania-based Axion Power International, in conjunction with BMW, has divulged testing results for its patented lead- carbon (PbC) battery technology – which will be marketed as a key component for cars with stop-start applications. Among the findings: The PbC battery cuts emissions by 12 percent and lasts four times longer than standard lead-acid car batteries, at a third of the cost of high-end Li-ion and nickel metal hydride batteries.
During the past decade, manufacturers have introduced stop-start cars – also called micro hybrids or idle-stop vehicles – that automatically turn off their gas-fed engines when the driver brakes to slow down or stop. In many cases, the stop-start mechanism has been bundled with other fuel-efficient technologies. These models, which rely on robust batteries and starter systems, offer as much as a 10 percent reduction in fuel consumption. They are priced slightly higher than cars with conventional internal combustion engines, but are less-expensive than hybrids.
According to Boulder-based Pike Research, Europe has by far the biggest market in stop-start vehicles –largely due to the aggressive EU emission reduction goals. By contrast, the research firm says, “North America has experienced a relatively slow penetration of the technology due to less stringent emissions reduction goals and an Environmental Protection Agency (EPA) testing cycle that underestimates the benefits of the technology.”
Pike forecasts that the market for stop-start vehicles will increase at a compound annual growth rate (CAGR) of 32 percent between 2011 and 2020, reaching a total market of 37 million vehicles sold annually by the end of the forecast period.
The test results from Axion Power International and its partner Munich-based BMW , demonstrate that, compared to a high-quality lead-acid type of battery (such as the absorbed glass mat [AGM] battery currently used in most stop-start vehicles), the lead-carbon battery provides:
- Ten times the dynamic charge acceptance;
- Four times the cycle life;
- Stable round-trip energy efficiencies in the 85 percent range; and
- Thirty percent lower weight.
The problem with AGM batteries is that due to a buildup of sulfur residue on its negative electrode, it can lose as much as half its charge after only two months of driving. The PbC battery, however, which replaces the negative lead electrode with one made up of carbon assemblies, corrects this flaw – enabling the battery to work, at full charge, for eight years—four times longer than the AGM battery.
Among the automakers who are interested in the new battery are manufacturers that typically build larger vehicles, such as BMW, Daimler, VW, and Volvo – and, therefore, face a much more difficult challenge in order to comply with the new EU requirements.
Indeed, BMW has been promoting a concept called “efficient dynamics”, which, according to its marketing materials, will improve efficiency and reduce CO2 emissions with “high precision injection, auto start/stop function, [and] brake energy regeneration,” among other functionalities. BMW’s long-term strategy is to power all of the electrical loads in the vehicle with energy that is recovered by regenerative braking.
Daimler also has announced the use of an auto start/stop function that will feature two lead–acid batteries and be available on all of their passenger cars within only a couple of years.
According to the Axion white paper, Hybrid Vehicle Market Trends, Battery Requirements for the Next Decade, and Advances in Lead Acid Battery Technology towards Reduced CO2 Emissions in Europe and the United States, even companies that produce smaller vehicles, such as Ford, Peugeot, and Citroen, have been selling start/stop vehicles – which is a critical step in qualifying a new technology before large-scale production can occur.
Previously, hybrid vehicle production has focused on mild and full hybrid vehicles such as the Honda (News - Alert) Civic and Toyota Prius Hybrids. Unlike the extensive technology change required to produce mild/full hybrid vehicles, micro hybrid technology requires only minimum modifications to the vehicle platform making it an economical and rapid performance enhancement for the risk-adverse OEMs. Therefore, Axion predicts that the technology will be adopted in the United States, if at a slightly slower rate.
Finally, as far as end-of-life recycling goes, all of the PbC battery's parts can be easily and inexpensively recycled, leaving little or no environmental footprint behind.The PbC battery currently is being tested by a U.S. automaker for possible inclusion in its fleet in the near future.
Cheryl Kaften is an accomplished communicator who has written for consumer and corporate audiences. She has worked extensively for MasterCard (News - Alert) Worldwide, Philip Morris USA (Altria), and KPMG, and has consulted for Estee Lauder and the Philadelphia Inquirer Newspapers. To read more of her articles, please visit her columnist page.Edited by
Jennifer Russell
