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.
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.
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.
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....
I heard that of 4 Chevrolet Volts involved in crash testing, 3 ended up burning down. 75% suffered total destruction. Of course I'm not sure I believe that, if Chevrolet conducted the crash tests and got those kinds of results then I'm sure they wouldn't have released the car for production.
anytime you sit in a vehicle that has enough stored enegery to propel a 4000+ pound object some 300 miles you are taking a risk.
Fortunately gasoline is a fairly safe fuel - its hard to ignite in bulk liquid form, msotly the vapors are extremely volatile.
The lithium is also hazardous, shorts created by physical shocks in abnormal conditions like collisions risk igniting the batteries. Apparently damage to the cooling system can also cause delayed fires - this is particularly worrisome because circulation cooling systems are active whereas all the gas tank protection is primarily passive in nature.
I guess we'll know a little farther down the road.
Manwhile, is it true that GM has only sold 6-10,000 of the very hyped Volts? Are they on track saleswise?
I'd also like to add that many automotive fires have been caused by far lower energy density storage devices, namely the lead acid battery! While the battery itself may have had few ignition issues the vehicle wiring has had plenty. A short in a starter motor solenoid can result in an overheating starter motor and/or its power cable. Fusable links in many instances have not opened on time. With the trend to thinner and thinner wiring to reduce vehicle weight and the talk about raising the bus voltage to 24 or 48 volts to further reduce losses, the peak fault currents will rise even for non electric drive vehicles.
Regardless of the energy source, the density and amount of "fuel" required to power a practical vehicle will always be dangerous. However, it is kinetic energy that poses the biggest threat to a vehicle's inhabitants.
I understand your question. Is there a significant risk to the consumer, like there was with the Pinto? Others appear to have missed the point. It is interesting that there have already been 3 fires, with so few sold. However, the question should not be asked if there is an issue with the Chevy Volt Lithium-Ion batteries but if there is an issue with all electric/hybrid cars with large battery systems. Lithium-ion batteries were not stable enough to be used in consumer products until very recently. Before this, they we would explode above 70 degrees F. Consumers tend to think batteries are benign things - safe. They are energy storage devices and if mistreated can hurt people. They do catch fire and when they do, they burn hot. They also explode and they tend to explode in a cascading fashion.
To me for Chevy to be willing to buy back the vehicles from worried purchasers means that GM is starting to pay attention to customer reaction; after all GM has a reputation of putting vehicles on the road and letting the customer find the bugs for them.
I don't disagree with all you state, I agree that if done appropriately, electrics will always be safer than a compairable gasoline car. Ultimately, any basic safety analysis would start with a comparison of energy density and volitility, both of which are higher with gasoline right now and probably will continue to be for the next 10 years... though batteries are improving.
Yes, my states aren't 100% comparable, you'd have to reduce everything and make it a per capita comparison. But still, one can look at this data and make a general order of magnitude comparison to draw the conclusions I did. If you disagree with the conclusions, then do the hard math and challenge them.... but I suspect your just challenging my methods and not my conclusions in which case I agree and attribute the problem to laziness.
I do disagree with the claim of "catostrophic failure" of lithum batteries when they fail. Again, an honest attempt at quick comparison, worst case senarios only: When a lithum battery falses, we end up with a short which could catch fire assuming the cooling system fails. When a gasoline tank fails, say in the case of the pino, gas leaks onto a hot surface, igntites, and could potentially ignitude the gas tank (it does happen though rarely) and you get an explosion. An explosion is obviously more dangerous than a fire in most circumstances. I could honestly say that a gasoline powered car could, theoreticaly, be more safer than an electric, but it would require greater isolation than their lithium battery counterparts due to energy density. They could cordin off the gas tank into isolated sections, but to pass the safety rating of electrics, it would have to contain more isolation. Generally, lithum batterys do not fail "catastrophically"... I mean, can you name one catastrophy that has resulted from a lithum battery failure? It all goes back to energy density.
Basically it was a design flaw that left the car more susceptible to fire in a rear-end collision. I was read-ended while driving a Pinto. The car was totaled, but no fire.
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
3 
