NAATBatt kicked off its electric bus safety initiative last Wednesday with the first telephonic meeting of the NAATBatt Electric Bus Safety Committee. I would like to extend special thanks to committee co-chairs John Warner and Dave Roberts and to Ben Wrightwood for their organization of the call and for their exceptional, if somewhat frightening, description of the problem that NAATBatt and its members need to address.
John Warner started by describing the size of the bus market in the United States and the nature of the mass transit bus fleet. In 2013 there were 71,699 transit buses of all types in use in the United States carrying about 7.6 million passengers. More than 40% of those buses have a power system that includes an alternative power source (anything other than diesel or gasoline, but including particulate-trap-equipped buses), with 17.5% identified as hybrid powered and about 0.1% identified as full electric vehicles. The bus fleet is also aging rapidly with an average age of 9.8 years and an estimated useful life of 12 years. About 7% of all buses are “rehabilitated” in order to extend their useful lives, with some of those rehabilitations involving the installation of a battery-powered drive train.
There is no special testing or certification of electric buses in the United States today. What testing there is for new transit buses is conducted by the Federal Transit Agency under its New Model Bus Testing Program (often referred to as “Altoona Testing” due to the location of the primary test facility). That testing program, however, focuses exclusively on structural integrity and durability, reliability, performance, maintainability, noise, and fuel economy with safety testing limited to handling and stability considerations. There is no specific testing, standards or certification of any large format batteries used in mass transit buses in the United States today, either in new or in rehabilitated buses.
Following several reported (and probably many more unreported) safety incidents, China has started efforts to regulate the safety of batteries deployed in its own fleet of electric buses, which is much larger than the electric bus fleet in the United States. Early this year, the Chinese government suspending the certification of “tri-metal” batteries (e.g., NMC and NCA chemistries) for use in electric buses because of safety concerns. As a consequence, electric bus safety is now more heavily regulated in China than in the United States—an absolutely stunning fact.
One of the participants on the call suggested that the safety peril of electric buses in the United States is the result of two distressingly common purchasing practices in the electrified bus market. The first is that the English-speaking sales and marketing personnel hired in the U.S. by primarily Chinese import companies tend to lack technical backgrounds and are overly reliant on claims they take on face value from the overseas parent company. The second is overly-aggressive BMS profiles used by imported products to “stretch” the range of electric buses. As a result there are many electric buses on the road today in the United States that are running BMS depth of discharge profiles that are far more aggressive than any U.S. light vehicle manufacturer would allow.
What U.S. industry needs to do about this issue is still an open question at NAATBatt. But it is clear that industry must do something. A serious electrified bus safety incident in the United States would be disastrous for every company involved in advanced batteries and electric drive.
The NAATBatt Electric Bus Safety Committee will meet again at 10:00 a.m., PST, on Tuesday, March 1 at the Hyatt Regency Indian Wells Resort & Spa, immediately prior to the start of the NAATBatt 2016 Annual Meeting & Conference. All NAATBatt members and other interested parties are welcome to attend. Please register for the 2016 Annual Meeting using the following link in order to participate in the discussion of this critical issue and to help shape a solution: https://naatbatt.org/conference-registration/
I look forward to seeing you in Indian Wells.