Electric car battery fires spark design scrutiny from engineers

GM's Cadillar Lyriq is part of an ambitious plan to expand electric vehicles and the carmaker is hiring 3,000 engineers and software developers to do the work. Meanwhile, a GM team is developing diagnostic software after safety problems with batteries led to recalls of some Chevrolet Bolt EVs. (GM)

 

President Biden promoted clean energy and electric vehicles in his new $2.2 trillion infrastructure plan while carmakers are ramping up production of millions more EVs in the next few years.

Unfortunately, some EV batteries have caught fire, raising the specter of safety and rattling some potential buyers. EV battery fires are infrequent, but the chances of one occurring have caught the eye of engineers at sensor startups who are designing new tech to track the health of batteries and prevent fires.

On a grand scale, General Motors is working up a software solution to put thousands of recalled Chevrolet Bolt EVs back in service.   General Motors said Thursday it is planning to roll out state-of-the-art software in April to allow early diagnosis of the potential for fires in recalled Bolt EVs.

“We have hundreds of engineers working around the clock on the issue and we have made progress on identifying the cause and potential remedies,” GM said in a statement to Fierce Electronics. A spokesman would not discuss the details of GM’s advanced diagnostics solution.

Last fall, GM issued a recall of nearly 51,000 Bolts in model years 2017-2019 for the potential of an unattended fire in the high-voltage battery pack under the back seat’s bottom cushion, according to the National Highway Traffic Safety Administration.

The vehicles’ cell packs have the potential to smoke and ignite internally, said NHTSA, which confirmed five known fires with two injuries. At least one of the fires spread from the vehicle and ignited a home.  The agency said until the vehicles have been repaired, the safest place to park them is outside away from homes.

GM recalled Bolts with high voltage batteries produced at LG Chem’s Ochang, Korea, factory. Those batteries may pose a risk of fire when charged to full or very close to full capacity. Meantime, dealers have a software update that limits the vehicles to 90% of a full charge.

Some experts are hopeful that GM will apply its Bolt diagnostics solution to other vehicles down the road.

Other EV battery safety problems have been reported leading to recalls. BMW recalled 10 BMW and Mini plug-in models in the U.S. last fall and Hyundai recalled Kona Electric SUVs in the States.

Underwriters Laboratories estimates about one in 12 million lithium-ion cells have caught fire but that is significant percentage with up to 8 billion cells produced each year, according to a CNN report.

Theoretically, sensors and related software will warn an EV owner in advance of a fire, reducing the chance of vehicle damage or personal injury.  EVs are generally equipped with Battery Management Systems to monitor voltage, temperature and wear in battery cells, but some experts say the systems don’t go far enough.

A Finnish lithium-ion battery diagnostics provider named Akkurate Oy recently announced new financing to accelerate further product development. It markets a remote monitoring and diagnostics product called Diagnose to offer real-time statistics on battery health to prevent potential safety problems.

Metis Engineering, a startup in Bristol, England, announced on Thursday a Controller Area Network-based sensor designed to detect the early onset of catastrophic battery failure.  It detects small increases in pressure inside a battery cell that can be caused by rising temperature when a cell is overworked or somehow has been damaged.

A pressure data spike triggered by a venting battery can be cross-checked with hydrogen, humidity and volatile organic compound levels in the Metis air quality sensor.  If a battery explodes, the sensor also can indicate the pressure that the battery enclosure has been under.

Typical Battery Management Systems often do not measure every cell temperature in an EV, which means that a single cell with an intrinsic weakness may not be detected early on, Metis said. Some EVs have hundreds or even thousands of individual cells inside a battery.

“Detecting early onset of battery failure in EVs will enable the industry to maintain the terrific rate of growth as new forms of electric transport are developed,” said Joe Holdsworth, manager director of Metis, in a statement.  “Detection will significantly reduce the risk of catastrophic battery failures.”

While detection technology is available in the short-term, some EV enthusiasts believe the long-term solution is for EVs to come equipped with a solid-state battery which contains no electrolyte, making it safer.

“The big breakthrough to watch is the solid-state battery,” said Matt DeLorenzo, senior managing editor at Kelley Blue Book, in a recent interview.

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