Chevy Volt batteries have caught fire. The National Highway Traffic Administration (NHTSA) is investigating, and General Motors has offered to buy Volts back from any owner who fears the electric cars will catch fire.
So does it mean the Chevy Volt is unsafe? The short answer is, no -- Volts won't be spontaneously bursting into flames on our nation's highways. Rather, according to experts we spoke with, the Volt fires prove that automotive engineers have been justified in employing elaborate and expensive cooling systems in their electric vehicles.
Chevy Volt in a side crash test, performed by the Insurance Institute for Highway Safety.
The truth is, there's always been a well-understood fire risk associated with lithium-ion batteries. "The chemistry is edgy," Donald Sadoway, professor of materials chemistry at the Massachusetts Institute of Technology, told Design News in an email. "The electrolyte is an organic liquid that is flammable, highly volatile at even moderately elevated temperature and in the presence of metallic lithium, which can form on the negative electrode at high charging rates."
Elton Cairns, a professor of chemical and biomolecular engineering at the University of California-Berkeley, explains: "In a lithium-ion battery, you've got electrodes that are tens of microns from one another. If you deform the cell case and it causes the electrodes to touch one another, there's an internal short circuit. That can cause the cell to rapidly discharge and, in so doing, heat up."
All of that might sound like a prescription for an epidemic of electric car fires, but it isn't. Why? Because of the aforementioned cooling systems. The Volt employs a fluid coolant that circulates through 1mm-thick channels machined into 144 metal plates that sit between the battery's cells. Using the coolant, the Volt draws the heat away from the core of its big battery.
Similarly, Toyota's Prius PHV, a plug-in hybrid, uses three fans for air circulation, along with ductwork, and 42 sensors to monitor the temperature of its lithium-ion battery. Virtually every manufacturer of production EVs also employs battery management systems and multiple microcontrollers to track the operation of the battery pack at every moment.
Remember, when GM first tested airbags, the prototypes kept decapitating the dummies.
The danger of any exotic chemical batteries and energy cells is well known. The Bolder TMF cell can do a similar job powering hybrids...Remember the Chrysler EXS created some time ago? Bolder uses a LEAD ACID combination with plastic shielding isolating EVERY CELL in the pack. That cell system was used in the ESX. No fires, no leakage except from the damaged cells in a collision...The amount of standard car battery electrolyte is contained in the matrix. No more than a few drops per cel actually leaks out.
Contrast that to the problems the ( re) VOLT (ing) has.
Used regular materials in power pack construction and the problem goes away.
Too bad the company got outsourced to the pacific rim....
Rod, according to Hollywood, your Pinto experience is not typical. If you do a survey of all car crashes in films or on TV, all car crashes result in fire & an explosion. This is specially true if you are a bad guy.
I think at this point we clearly don't know the complete range of risks in the Volt. Nor, re the earlier comment, do we know exactly how many Volts have been sold. We'll be keeping up with both issues in our continuing coverage on Design News; thanks for the comments and for bringing these issues to the fore.
We still don't know enough about what happened and when we do, we will report it. But too many times, stories in the newspapers and TV news about such subjects take on the apperance of a witch hunt, then they disappear. Consider Toyota's unintended acceleration "problem." Little was written when Transportation Secretary Ray LaHood said this after the NHTSA investigation: "The jury is back. The verdict is in. There is no electronic-based cause for unintended high-speed acceleration in Toyotas. Period." And what about the infamous General Motors pickup trucks -- the ones that were profiled on NBC Dateline in a story called "Waiting to Expode?" Those vehicles, too, were supposed to be death traps...until it was learned that NBC faked the explosions with remote control explosives. Again -- I repeat -- we don't yet know what happened here. And, yes, there are anomalies. So, yes, government agencies should certainly investigate this fire (or fires, as the case may be). But until we do know anything definitive, I'm siding with the engineers. For the most part, they have a good track record.
Yes, Hollywood does love its pyrotechnics. Hollywood does twist your expectations. Makes you wonder why more of the accidents you see at the side of the road are not bursting into flames.
That's over 300,000 gasoline vehicle fires per year.
Any time you store large volumes of energy there is the risk of fire. I'd rather be sitting in a vehicle with a well-designed battery pack than a tank full of highly flammable gasoline.
Alongside gasoline-fueled fires, a big cause of automotive deaths remains distracted driving. According to the National Highway Traffic Safety Administration (pdf download), some 33,000 deaths were caused in 2009 by drowsy driving. I don't know if there are stats yet for accidents caused by texting while driving, but I'd bet the numbers are pretty scary. That said, this stuff as well as gas are discrete from the issues raised by Lithium Ion batteries, which need to be investigated.
I'm not saying that it doesn't need to be investigated. I'm just saying that we have to put the risks in perspective. Gasoline fires are depressingly common.
We should also note that the fires in question happend a week or two after the damage to the pack was incurred. Most people don't sit in their damaged cars for two weeks.
Good point, dgb. Consider this: A gallon of gasoline contains about 30 kWh of energy. That means that a 15-gallon gas tank holds about 450 kWh. In contrast, a Volt battery contains 16 kWh -- equivalent to about half a gallon of gas.
These batteries have caused numerous product recalls including thousands of computers and just last month I got a message from Apple recalling my 1st generation, 5 year old iPod due to battery fires!! Apparently as these units aged, they have become more susceptable to initiating fires.
As with all systems, we learn to live with risk managment, by both the provider of the product and the user of the product. However, as systems become more complex, the potential failure modes increase and the reliability decreases. Just remember that the more cells you stuff in a battery and the more electronics you pack around it and its vehicles interfaces, the higher the probability of a failure.
With LEDs dropping in price virtually every year, automakers have begun employing them, not only on luxury vehicles, but on entry-level models, as well.
The 3D printing revolution seems to have a knack for quickly moving technology ahead by way of collaborative effort and even a little friendly competition -- all of course in the name of scientific advancement.
Advantech has launched a new series of motion-control I/O modules to meet the increased demands that come with more distributed industrial systems that require control of a growing number of axes and devices.
Using almost 200 light-emitting diodes in the front and back of the new 2014 CTS, Cadillac designers are showing how LEDs can change the character of a vehicle.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 3
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
A quick look into the merger of two powerhouse 3D printing OEMs and the new leader in rapid prototyping solutions, Stratasys. The industrial revolution is now led by 3D printing and engineers are given the opportunity to fully maximize their design capabilities, reduce their time-to-market and functionally test prototypes cheaper, faster and easier. Bruce Bradshaw, Director of Marketing in North America, will explore the large product offering and variety of materials that will help CAD designers articulate their product design with actual, physical prototypes. This broadcast will dive deep into technical information including application specific stories from real world customers and their experiences with 3D printing. 3D Printing is
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
4 
