by E. Reta Sober
July 31, 2018
Lithium-ion (Li-Ion) batteries have been in the news a lot recently.
Valued for their light weight and powerful energy storage potential, Li-Ion batteries are finding increasing applications in a diverse range of products, including motor vehicles. But Li-Ion technology is still developing and, as such continues to experience growing pains.
Li-Ion batteries are particularly susceptible to thermal runaway, during which a cell’s temperature increases unrestrained until the cell catches fire. Thermal runaway is most frequently the result of manufacturing imperfections or damage to the cell.
High-speed vehicle collisions are the leading cause of electric vehicle (EV) fires, as in the case of a fatal crash involving a Tesla Model X in the Bay Area this past March. Similar events have transpired in Austria and Switzerland as well.
On occasion, however, EVs have caught fire long after an accident, such as the Tesla Model S in Yorkshire that received repairs after a minor fender bender but dissolved into flames while parked two weeks later.
More disconcerting are instances in which previous damage did not precipitate the blaze, as when a Model S caught fire while parked, but not charging, at the Jinquiao Supercharger Station in Shanghai in March 2017.
And still other EV fires have resulted from bad electrical connections – including the Model S that caught fire during a test run in Biarritz, France in August 2016 – or apparent short circuits, as when a Model S burned down while charging at a Supercharger in Gjerstad, Norway or when 55 Anhui Ankai Automobile electric buses burned to the ground at the Crab Island amusement park in Beijing in May 2017.
Fires involving EVs pose unique challenges for first responders, who are trained in how to handle gasoline fires but less well prepared for dealing with electrical emission hazards. While Tesla advises applying water directly to the battery to cool the cell during an incineration, water may prove ineffective against a Li-Ion battery fire (water with copper material is more effective, though limited availability and funds make it a less viable option). In most cases, quarantining the vehicle and letting the fire burn itself out is the best option!
In addition to soot, Li-Ion battery fires can also release high levels of toxic gases, such as carbon monoxide, hydrogen fluoride, and metal particulates. As a result, additional safety measures such as SCBA respiratory protection, fog streams, and high-velocity positive-pressure ventilation fans that protect bystanders downwind are necessary.
No OEM wants their vehicles going up in flames – it’s just not good press! And given the impact such malfunctions can have on consumer confidence in and perceptions of a brand, OEMs have understandably taken great strides to prevent EV fires and help consumers recover when they occur.
For example, Tesla maintains a dedicated first responders page, which includes model-specific emergency response sheets and guides. The company also equips its vehicles with a “cut loop” inside the front cargo compartment that, when severed, will deactivate most high-voltage links in the vehicle. A second cut loop can be found in the rear of the vehicle.
Still, EVs are no more likely to meet a fiery end than other vehicles: any energy storage device carries a risk, and most EV fires follow a high-speed accident.
Moreover, there are hundreds of thousands of vehicle fires in the US every year, with Ford recalling 570,000 vehicles susceptible to engine fires in 2017. Likewise, Hyundai-Kia began recalling more than 37,000 hybrids worldwide on June 15, 2018 due to an oil leak that could result in fire. Driving an EV poses no greater risk to the driver and occupants than using other motor vehicles on the market. Thus, while EV battery technology certainly should be improved, the larger battle facing EV manufacturers is that against bad press.
Need more information? For historical demand data and forecasts by product, region, and vehicle segment, see The Freedonia Group’s Global Hybrid & Electric Vehicles study. This study also covers market environment factors, industry structure, company market share, and leading companies.
E. Reta Sober is an industry analyst at The Freedonia Group where she writes studies related to electrical equipment, machinery, and the automotive industry.
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