Technological improvements and falling prices of battery technology will see more electric vehicles (EV) on the road in the coming years. Many automakers including, Tesla, BAIC, BMW, Volkswagen, BYD, Hyundai, Mitsubishi and Renault-Nissan are offering various EV models, with a range of body styles and pricing. However, the recent explosions of two Tesla Model S in Hongkong and Shanghai, a NIO ES8 at a residential plot in Wuhan City, China, a Tesla Model 3 on a highway in Moscow and a Hyundai Kona in the owner’s garage in Montreal, Canada, have created doubts among car buyers about the safety of electric cars.
The probability of an EV catching fire is actually lower than cars with internal combustion engines (ICE). According to the Fatality Analysis Reporting System, fire was found in 2.6% of EVs and 4.4% of ICE vehicles, in cases of fatal vehicle crashes. These cases were analysed between 1993-2013 in the US from a database of 60,000 annual crashes. This blog explains the reasons EV catch fire and looks at initiatives being taken by automakers to make EVs safer.
Too many charging standards to follow:
EV chargers follow standards including CHArge de Move (CHAdeMO), Combined Charging System (CCS), Tesla Supercharger, and Guobiao (GB/T). Different charging standards also increase the chances of the problem in supplying different power and voltage for charging infrastructure builders. A uniform global charging standard can go a long way to overcome this issue. In 2017, Infineon, and STMicroelectronics joined Charging Interface Initiative e.V. to develop global charging standard.
Overcharging and overheating are the reasons for damaging battery cells:
Electric vehicles are safer than ICE vehicles due to lower flammability of Li-ion batteries. However, liquid electrolyte in battery cells can overheat with prolonged exposure to defective voltage regulators, alternators or the improper use of chargers. Thermal runaway can occur leading to a fire. Even, charging EVs designed for slow charging with fast chargers can damage battery packs, charging connectors, and compromise battery integrity.
Electric vehicles need small but periodic maintenance:
The electrical systems used in electric vehicles including the battery, electric motor, and related electronic components, require periodic maintenance. Even though EVs required less maintenance than ICE vehicles, ignoring the need for servicing can lead to compromised safety.
More preventions should be taken in battery and wiring harness design by automakers:
NIO, a Chinese EV start-up recalled nearly 5,000 ES8 electric SUVs built between 02/04/2018 and 19/10/2018 for fire catching risk. In June 2019, Audi also recalled more than 540 e-Tron models in the US due to problems in the wiring harness, which was causing moisture to seep into the individual battery cells. Automakers should continue to check more with potential issues with battery design, high voltage wiring harness, battery boxes, waterproofing, charging, and temperature management.
Additional safety measures taken by EV automakers:
- Most automakers have shifted to liquid cooling technology to keep the battery temperature in a safe range while the car is in use.
- Tesla uses an extra aluminium plate for fire protection between the battery pack and passenger compartment. This is not mandatory or standard yet in electric vehicles.
- Leading automakers including Toyota, Tesla, Volkswagen, BYD and BMW are investing heavily in developing next-generation solid-state battery technology that should lead to safer batteries.
Electric vehicles reduce tailpipe emissions and operating costs, but their new technologies create new problems. The combined efforts of automakers, component suppliers, battery suppliers and regulatory authorities will help to make electric vehicles safer and assist the transition towards electric mobility.