Crashworthiness testing of electric and hybrid vehicles

Electric and hybrid vehicles are increasingly being offered as a means to provide personal transportation with less negative impact on the environment and lower operational cost. While still representing a small portion of fleets in industrialized countries, the availability of these types of vehicles is growing. Electric and hybrid vehicles comprised approximately 1 percent of new vehicle sales in the United States in 2004, and by 2013 this had grown to almost 4 percent. As a result, there is considerable interest in the crash safety of these vehicles and, in particular, potential hazards unique to their electrical drive systems such as electrocution, fire, and electrolyte spillage. This paper summarizes the crash test experience of electric/hybrid vehicle from the Australasian New Car Assessment Program (ANCAP) and Insurance Institute for Highway Safety (IIHS). Since 2004, ANCAP and IIHS have subjected 42 hybrid and electric drivetrain vehicles to a variety of crashworthiness tests including both moderate and small overlap front crashes, side crashes, and roof strength tests. Crashworthiness results are summarized with special attention paid to the risk of electrical drive system hazards, and laboratory best practice related to electric vehicle testing is described. The crashworthiness of hybrid and electric drive vehicles is typically similar to that of vehicles with internal combustion engines. IIHS has assigned eight good ratings, three acceptable ratings, and three poor ratings in frontal crash tests (both moderate and small overlap tests); 10 good ratings and one poor rating in side crash tests; and eight good ratings and one acceptable rating in roof strength tests. To date, ANCAP has assigned one 4-star rating and two 5-star ratings to electric vehicles in its evaluation program. Neither organization observed damage to the batteries or other portions of the electrical drive systems that indicated a potential risk. Safety precautions and inspections of the electrical systems have evolved to include post-crash checks for isolation of high voltage from the chassis, leakage of volatile gases, and physical damage of the systems. In addition, vehicles are quarantined and observed after a test to ensure hidden damage does not result in fire risk developing over time. Ten years of crash testing electric/hybrid vehicles by ANCAP and IIHS, covering a wide range of crash conditions, indicates the variation in crashworthiness performance of hybrid/electrical drive vehicles is comparable with the variation observed with conventionally powered vehicles. Neither ANCAP nor IIHS has observed problems associated with the electrical drive systems in tests of more than 40 hybrid and electrical vehicles. This observation suggests safety designers are providing good protection of the electrical drive systems in crashes represented by federal and consumer information tests. While vehicles with high-voltage batteries present unique challenges to laboratory safety, ANCAP and IIHS experience suggests these potential hazards can be managed. Using appropriate tools and taking extra steps to ensure isolation of the battery from other parts of the vehicle has resulted in the successful execution of electric vehicle crash tests by both organizations without injury or other dangerous incident.