OT - Chevy Volt/Electric Cars

Submitted by JeepinBen on July 14th, 2010 at 4:08 PM

Saw this article today 


Talking about how Chevy plans to offer an 8 year warranty on the battery in the Volt.

I took an Internal Combustion Engines class at Michigan (ME 438) a couple of years ago, and a main concern of the professor was the battery life/robustness over the lifecycle of the vehicle. His example was laptop batteries. They often have crappy lifecycles - they last 6 hours when you buy the laptop, within a couple of years, 3 hours.

Based on this example it seems like hybrid batteries will be similar, they're both pretty advanced battery technology, and i know laptop batteries are getting better, but I think that a diminished range is a real issue with hybrids/electric vehicles moving forward.

Anyone (EEs? CSEs?) know why GM is ready to stand behind these batteries (the single most expensive part of the vehicle) this long? If battery technology is this advanced, I think electric cars might really be the way to go in the future (although you can't get a stick shift hybrid... so that's a no-go for me)




July 14th, 2010 at 4:19 PM ^

I'm a Mechanical Engineer, and I like IC as well. The problem is if it is dying, and if it should. I think that hybrid technology can actually help IC engines (it allows them to be better programmed/more efficient/run Atkinson cycle rather than Otto) but I don't like the downsides (expensive batteries dying every 2 years, no manual transmissions, impossible to work on at home, etc.) 

Thats why I figured i'd see what other people thought


July 14th, 2010 at 6:48 PM ^

You should still be able to do this - as long as there are moving parts in a car, there will be maintenance required that can be performed at home. And while the drive train is completely different, there will still be a transfer of power from the motor to the wheels where you can tinker around. It'll help to plug into your car with a computer if you're a weekend stock racer, but that's true with most of today's IC cars that use electronic fuel injectors, right? Not being a weekend racer I'm not sure, but I didn't think that you guys used carburetors.


July 15th, 2010 at 8:55 AM ^

The big issue with working on them at home comes from the huge electrical charges associated within the vehicles. 

When the Prius came out (i want to say the 2nd gen?) in the service manual there were  specific instructions as to where you can do maintenance at home, and where you cant. If you touch certain areas of the hybrid (without gloves/boots) you can die. Most systems on the hybrid are un-work-on-able except in a really controlled environment (Rubber mats on the floor, rubber boots, rubber gloves, NO WATER... good luck in a Michigan winter) that means that a lot of these vehicles can't be serviced at home or by your general mom-and-pop repair shop. You have to go to dealers for most hybrid services.

Wheels and tires, and some interior stuff would be fine, but all powertrain systems, brakes, that kind of stuff is now too electronic to mess with on your own


July 14th, 2010 at 4:23 PM ^

Who also heard similar concerns about Li+ batteries in a combustion class, I believe that GM is probably taking the cost of replacing the batteries upon themselves. There was also talk in the class about how useful batteries that would no longer meet standards for cars can be sold to utility companies to help "level" the production of electrical power, so it may make more business sense to warranty the batteries for a long time in order to ensure they're off the road yet still being used.


July 14th, 2010 at 4:25 PM ^

Its a marketing issue. Very likely, GM's focus groups brought to light a question of confidence in new technology and/or new infrastructure. The 8-year warranty is meant to provide would-be buyers a measure of confidence that GM will stand behind its vehicles. I'm willing to bet that the warranty does not cover battery life, however, only durability issues of the battery pack itself.


July 14th, 2010 at 4:32 PM ^

They do not intend to make money on this car. They will limit the production and lose money on each one, but benefit from the PR and move up the learning curve. FWIW, they make all their money on trucks right now.


July 14th, 2010 at 4:31 PM ^

A couple things:

- GM's designed the Volt so that the gas engine kicks in to power the battery when the battery drops below something like 25% of total charge, and they've also fixed it so that when you plug in the battery, it doesn't charge up beyond something like 80 or 85%.  That's for battery-life purposes - they die when you do things to them like charge them all the way and then run them down all the way, over and over and over.  Laptops usually just drain the battery all the way.

- If GM's right about their 40 mile thing, people aren't gonna drive the car long enough to kick in the gas engine frequently enough to notice the battery life cutting in half, even if it does, which because of the above, GM figures it won't.

- The warranty probably covers total failure of the battery, not a gradual burnout of its lifecycle.


July 14th, 2010 at 5:26 PM ^

I work for a company that supplies batteries for the OEM's.  The battery chemistries that are used in hybrids and EV's are expected to last 10 to 15 years, which means that they have to meet a power requirement after 10 years and 15 years, and is based on cycles rather than miles. So yes the range will go down after extended use, but the industry is trying to push these limits even further. GM's 8 year warranty is pretty understandable for a new technology and is similar to what Mazda ended up giving for its rotary engine. I would not expect a large drop in range until 12-15 yrs if the cells were made well.

The main issue with battery technology is weight and cost. Economies of scale would hopefully bring cost down. There are also some new lithium technologies that could have amazing power density, but are years away since they can only accept 1 charge. Anyway, hope that helps.


July 14th, 2010 at 6:01 PM ^

I took ME 438 last year; great class, but Assanis wasn't teaching it. I do engine research at Michigan, so I may be a little biased, but I don't think the technology is there yet for electric/hybrid vehicles. I think GDI, HCCI, and small-scale diesels are the best choice right now until the energy density of battery technology catches up. I saw a study out of UW that uses a gasoline pilot charge and a diesel main charge and got great fuel economy and emissions.


July 14th, 2010 at 6:36 PM ^

If I remember right, HCCI isn't quite there yet either, right? I also remember that we're getting a lot closer to controlling the emissions from diesel engines, which would be awesome.

To the OP: IC engines still have so much room for improvement, it would almost be a shame if they actually did become obsolete before being optimized. But even the Volt's generator runs on IC, so if plug-ins do become affordable for the average car buyer tomorrow, there's still a place for the IC engine. It may not be in the traditional Otto cycle, and may not directly run the car, but it's stil internal combustion.


July 14th, 2010 at 7:04 PM ^

I work in emissions, and actually, new diesel engines on many cars (not big truck diesels) run cleaner than the comparable gas engine.  This is mainly due to much stricter emissions regs for diesels and Urea systems to clean the exhaust, but the particulate emissions on diesel vehicles are almost nonexistant.

formula 1

July 14th, 2010 at 10:32 PM ^

If by GDI, you mean Gasoline Direct Injection, then it is in production already in many vehicles. The first vehicles to market with this technology was Audi a few years back. Then BMW, Mercedes, GM, Ford etc. have followed with implementations since. Current production cars with GDI in include the Cadillac CTS, Ford Mustang , BMW 1,3,5,7 series, and many others.


July 15th, 2010 at 9:06 AM ^

Mitsubishi started with GDI back in the 80's and stratified charge worked great. The problem with it was emissions related. The stratified charge produced more soot and particulate matter in the chamber, and we weren't good enough at post combustion exhaust treatment, so we couldn't use this form of combustion

Now we are much better at post-combustion emissions cleaning, and Direct Injection is again an option. A good example is the new Mustang/Camaro V6s, they get huge power, and good economy out of GDI.

The main future of IC engines (I believe) is somewhat of a molding of typical gasoline and diesel technology. There are already a lot of cross overs (GDI, turbocharging, glow plugs for diesels) This is where HCCI comes in, it's another blending of the gas and diesel technologies. 

I think that what will be interesting is where the $$ comes in to do this kind of research. the IC engine is a pretty un-tapped resource in a lot of ways. A typical Otto cycle is about 25% thermodynamically efficient (for every 4 calories of chemical energy in with gasoline, you get 1 calorie of mechanical energy out) while diesels start at around 35-40%. Adding complexity (Turbo/supercharging, GDI, etc) ups this percentage. The issues come in with costs. The main reason a diesel is more expensive than a gas engine (Think Golf vs. Golf TDI) is that diesel engines are a lot more complicated to design and build (and, as mentioned elsewhere, have more complicated exhaust aftertreatments) 

VW is actually currently working on a "dual charger" (or twin charger, i cant remember) engine that is about 1.3L and gets 200 HP. It's got a supercharger for low RPMs and a Variable Gate Turbocharger for the higher RPMs... Dunno if it's coming state side, but I think this kind of research and development is just as important if not more important than electric vehicle technology. 

Glad to hear I'm not alone here on the board, and that there are plenty of ME's./Car Dorks who stand by the IC engine

Steve in PA

July 14th, 2010 at 8:00 PM ^

I think it was called Mark V or something like that.  It was a Freestyle with a hybrid diesel/electric drivetrain.  I was very interested, but I think they've dropped it.  I'm very interested in the Nissan Leaf with a range of 100 miles.

I like the idea of "tinkering" with electric cars at home.  Most of my electronics are "modified" and my daughter's Barbie Jeep has been hotrodded.  I wanted to just replace a burnt up motor and found http://www.modifiedpowerwheels.com/.  Her Jeep is now 2x as fast and the batteries/motors were cheaper than stock.

GM standing behind the warranty is not difficult at all.  They have the backing of the US government and the associated credit line that goes with it.  Someone mentioned earlier that they make their money on trucks and last I saw that was still 100% correct.


July 14th, 2010 at 7:34 PM ^

if you want to further a new technology.  This takes any concern out of the customers mind and they can focus on the purchase of a vehicle that moves the country away from our oil infatuation.  Battery technology has come along way.  However, there will be issues as with any new technology ... even gas-powered vehicles have an extended warranty ... go figure.  In this case, the customer is protected.  Go Blue!


July 14th, 2010 at 9:28 PM ^

A bit away from the topic at hand but it's likely to be a major factor nonetheless.......

I think the biggest factor working against the Volt might be the payoff period, as it relates to smaller cars, such as the Cruze. I don't think it's going to be the reliability of the batteries. A few admitted assumptions here:

I think I read that a Volt is going to sell for ~ $40K, with a $7,500 tax credit, for a net of about $32,500.

A Chevy Cruze will probably go for, what, $18,000? Let's assume that these prices are after sales tax, delivery charges, etc, and absent of any interest charges on any monthly payments.

There's a $14,500 price difference there, after tax credits. For the average consumer, the logic behind buying the Volt, primarily, is to save money on gas. Let's take the Volt at face value and say that it gets the 250 MPG that GM was talking about a few months ago. Let's also assume that the Cruze will return 40 MPG. Let's assume all maintenance costs are relatively comparable, and that the batteries in the Volt hold up (both dangerous assumptions, but let's not make too much of a mess here, shall we?).

After 100,000 miles, the Volt has used 400 gallons of gas over the life of the vehicle. The Cruze has used 2,500. The Volt has saved 2,100 gallons of gas. At $3/gallon, the Volt has saved $6,300, far short of the $14,500 price differential.

The payback period, with gas at $3 per gallon, is just over 230,000 miles.

At $4/gallon, it's just over 172,600 miles.

At $6.75/gallon, it's just under 102,300 miles.

People aren't going to like what I have to say here, but if General Motors is going to put a $40,000 price tag on the Volt, people are going to be far better off financially buying the 40 MPG Cruze instead of a 250 MPG Volt, unless gas prices go absolutely apeshit over the next 5 years, far more than what we've seen in the past 3-4 years.


July 14th, 2010 at 9:49 PM ^

but the value is probably not going to be the reason most buyers are going to buy this car. Most will probably be early adapters who want something that makes them feel better by driving a car that drives 90% of the time in electric mode. The majority are probably already wealthy (celebs) who want a limited edition car that makes them feel superior to the average schmo driving a gas car or truck. This is a test run to support future technologies that will allow quantity of scales to get the price down for the average consumer.


July 14th, 2010 at 10:37 PM ^

You realize that the electricity to move the car when running on battery mode has to come from somewhere right? And it's likely a coal fired plant that then incurs losses in transmission from the plant to your car? Anyone that thinks hybrids are the future likely failed their math classes as a child.


July 14th, 2010 at 10:46 PM ^

I agree that what we available today is not the final solution, but you gotta crawl before you can walk right? If tree huggers wanted to drive the most eco-friendly vehicle they could it would probably be a small diesel car. But IC technology is getting close to plateauing, I hope that some of the development being done today can lead to some REAL efficiency breakthroughs in the future.


July 14th, 2010 at 10:51 PM ^

Sure, but it's a shame so much money is being wasted on ethanol and electric cars when the technology to implement clean diesel/bio-diesel exists. Plus, think about what happens when you have to dispose of that battery pack. Lots of nasty chemicals.

Besides, the better solution is smaller, less powerful cars and people making an effort to use less energy. Instead we get people thinking they are saving the environment by driving a hybrid.

To your edit: Sure, once higher compression, small turbos, DI, and a couple other technologies are cost effective, paired with a small car you'll see the equivalent of Jetta's getting 50mpg.

Oh wait shit that already exists.


July 14th, 2010 at 11:04 PM ^

I am fully aware the electricity is not magic and does not come from hugs and rainbows. I also understand that there are going to be mechanical and electrical losses in any system. As stated earlier I actually an ME from Uof M (had to do ok in math to do so)  that works on batteries for hybrids and electric vehicles and understand that they are not perfect systems. The point of electrification is that although most of the electricity comes from coal plants, there are a lot of new technologies that allow for us to diversify where we get our electricity from. This includes, hydro, wind, solar, nuclear, coal, even collecting the methane from manure to create energy. The idea would be to diversify where we get our energy so that we can become more energy dependant (this still includes gas) and use more renewable resources to accomplish this.

There are also some benefits to the coal burning plants as well.  Currently, power plants are not efficient as they have to provide a lot of energy during the day, while having to cut back at night. Electric cars would help balance out this inequity.

Does this mean I own a hybrid, no. Does this mean that I am going to go buy the Volt, no. Do I understand the importance of the vehicle, yes. My comment before was purely a response to describe why people would buy the Volt, and its not because they are going for the most economic value.


July 14th, 2010 at 11:55 PM ^

I agree with your statement and appreciate the response. I just want to clarify "Electric cars would help balance out this inequity." I get that the power costs to bring capacity online is a waste if that capacity could remain constant, but the flattening would be better served if peak was reduced rather than off-peak increasing.

Edit: Not because I didn't think you understood the inequity, but I don't want people that aren't familiar to think adding more electricity demand at night is a good thing and start running their lights overnight just cause.


July 15th, 2010 at 9:08 AM ^

Comes from small children in the form of screams and laughs. I saw it on Monsters, Inc. And everyone knows that laughter has a far greater energy density.


July 14th, 2010 at 9:55 PM ^

will be around for a very long time. In the short term, there's nothing that can really compete on a cost and practical basis. Significant investment is still needed in battery development and infrastructure for providing charging stations. In the meantime IC will continue to improve efficiency (whether or not technologies like HCCI pan out). And even as oil prices go up and make electric more cost competitive, renewable IC fuels will also become more competitive, whether this be biofuels, natural gas, or hydrogen. Even longer term one has to start thinking about lithium being a limited resource, especially with it's growing everyday demand. Some might point to fuel cells but there are large hurdles to overcome in membrane technology. Even then a hydrogen powered IC engine may be better when considering chemical requirements and sustainability issues with fuel cells.


July 14th, 2010 at 10:38 PM ^

Nissan is claiming 70-80% percent battery life after 10 years for its new Leaf. The only catch is, of course, that battery life is affected by charging habits.
Type: Laminated lithium-ion battery Total capacity (kWh): 24 Power output (kW): Over 90 Number of modules: 48 Battery pack
Charging times: -Quick charger DC50kW (0 to 80%): apx. 30 min -Home-use AC240V charging dock (0-100%): less than 8 hrs Battery layout: Under seat & floor Battery life: After 10 years, the battery is expected to have 70-80 percent of its original storage capacity



July 14th, 2010 at 10:43 PM ^

I read something about six months ago (it might have been Motor Trend) that when Ford was testing their Fusion Hybrids, they were going to rate the batteries to last 150,000 miles, and there were many instances where the batteries were topping 300,000 miles. If GM can do that, they have an out-and-out winner on their hands, assuming that they can drop $10K off of the sticker over the next few years.

As it stands now, the Volt is a niche vehicle. Companies such as General Motors do not survive on niches. Otherwise they could just sell a few Corvettes and call it a day. If they can lower the price of the vehicle over time, and the batteries can hold their own north of 150,000 miles, this will become a mainstream vehicle over time, and a winner in the showroom.