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GM Provides Glimpse of Battery Strategy and Approach for the Future with Briefing on Gen 1 Volt Pack; Work on Gen 2 and Gen 3 Packs Already Underway, With a Focus on Cost

by Mike Millikin and Jack Rosebro

The Gen 1 Volt 16 kWh pack, comprising more than 200 cells grouped into modules. GM is defining a “reuse” strategy for cells, packs and modules within its future vehicle line-up. Click to enlarge.

Three key General Motors executives involved with the Chevrolet Volt this week held a media briefing on the state of GM’s battery pack strategy for the Chevrolet Volt and its current Gen 1 pack as well as subsequent generations (Gen 2 and Gen 3) of battery packs destined for the underlying Voltec platform. They also delivered an update on the progress of the Volt’s development cycle.

Executive Director of Global Engineering–Hybrids, Electric Vehicles, and Batteries Robert Kruse, Volt Vehicle Chief Engineer Andrew Farah, and Director of Global Battery Systems Engineering Denise Gray took turns describing work completed so far as well as next steps for the project.

GM is emphasizing the role of thermal management and control systems in the overall pack and vehicle performance. Click to enlarge.

Kruse took particular care to note that, while having an excellent battery cell is important, the cell is just the starting place. GM views its value-add to the overall pack—and hence to the vehicle—as the thermal management and electronic controls. That rationale lies behind the company’s determination to manufacture the modules and packs for its vehicles in its own plant. (Earlier post.)

Kruse said that GM has developed all the software, electronic controls and pack engineering in-house, and that the process will continue with the portfolio into the future. GM regards the ability to do so as a core competency, and GM therefore made the strategic decision to have that capability inside the company.

Undertray of the Volt, showing the integration of the T- shaped battery pack as a structural element. Click to enlarge.

The current state of the Volt. More than 30 mules—similar-sized Chevrolet vehicles that have been modified to accept Volt powertrains—are already up and running, with another 50 expected to be built and put through their paces by the summer.

The team reiterated its commitment to the Volt’s 40-mile all-electric range (AER), especially as compared to a vehicle with the attendant costs of a battery pack with a several-hundred-mile all- electric range, but said that no commitment had yet been made on the business model (e.g. sale or lease) that will be employed for the Volt’s 16 kWh battery pack when the vehicle goes on sale November 2010, a date to which GM remains “confident and committed,” according to Kruse.

Undercarriage of the Volt during the 35 mph crash test. The battery pack is the orange T-shaped element. Click to enlarge.

A 35 MPH frontal crash test has already been conducted on at least one Volt mule to the satisfaction of the company, with particular emphasis given to the integrity of the battery pack during the test. Kruse also emphasized GM’s preference for fast charging as opposed to the “battery swap” model promoted by Better Place, which would require a significantly different chassis design and which Kruse termed “problematic”.

We began in January 2007, we are on track, and I think in some places we have accelerated our learning,”" commented Denise Gray, who runs GM’s battery development labs, which the company says are the largest in the country. “We spent all of 2008 evaluating cells.

Despite current market conditions, GM is still aggressively developing talent from within the company, with fifty engineers currently enrolled in a “learn while you earn” program related to the Volt, and another 50 expected to be transferred to the program this summer.

While officials emphasized that they are satisfied with the chemistry, thermal management, controls, and performance of the vehicle’s current battery pack, costs per kWh remain high, and development beyond the current pack is primarily focused on cost reduction. Gray noted that the costs of battery-powered personal electronics have declined sharply and expressed optimism that the transport sector might see similar gains. Each of Volt’s 200-plus battery cells will initially be produced in South Korea by LG Chem. However, GM plans to move battery production to the US as soon as possible.

Although the team declined to specify a cost per kilowatt-hour for the Volt during the briefing, Jon Lauckner, Vice President of Global Program Management, rebuffed speculation earlier this month, writing on the GM Fastlane blog (earlier post) that the current Volt battery pack is “many hundreds of dollars less” than the US$1,000 per kWh cited in a recent Carnegie Mellon study, and that “new concepts” promise to move the cost to as low as $US 250 per kWh.

Remarking that “I’m only going to do this job once,” Kruse mentioned another cost-cutting measure: the decision to design the global platform to more stringent European Union recyclability standards.

Gen 2, Gen 3 and Reusability. GM, said Kruse, is “thinking long term with our EV strategy.”

We are making a significant investment in vehicle electrification in the Volt, the Voltec powertrain and the battery itself. We believe that vehicle electrification is the future of the industry...and that master of battery technology is key to us and our success. We still have a lot of work to do. We are very encouraged by what we have done so far, and are gaining optimism with experience and exposure.

Because of our commitment, we have resources working on Gen 2 and Gen 3 [battery packs] while we are still launching the Gen 1 system. That speaks to our long-term commitment to vehicle electrification.

—Bob Kruse

GM’s “reuse” strategy. Click to enlarge.

The primary motivation for the Gen 2 and Gen 3 systems is to reduce cost, to make it more viable for the mass market, Kruse said. The GM team did not engage in a deeper discussion of the potential relative contribution of cells, thermal management and controls to reducing the cost in Gen 2 and Gen 3, but Kruse did say that “as we get close to production, we’ll take the cover off of the T pack, and you’ll see the sophistication and elegance of design.

Kruse did outline what GM is calling its “reuse” strategy in the battery area—i.e., the ability to apply cells, modules and packs across different vehicles:

  • Cells. Cells of the same specification will be widely applied in a range of vehicles.

  • Modules. Cell modules will be used across a class of vehicles/applications.

  • Complete packs (including controls). Complete packs will be applied across vehicles within a architecture. The Volt pack, for example, will be applied in the Opel Ampera.


Account Deleted

Good to hear that they are on schedule. GM appears to believe that fast charging will rule over battery swapping and that makes sense to me. Apart from GMs argument about design flexibility it is also a problem that a battery swapping station will be extremely expensive to build compared to a fast charging station. Furthermore, many batteries can now be charged to 70% capacity in less than 10 minutes and the latest discovery in nanodoping by MIT promises even better charging times in the future. To quote a Gismac report “The specific power observed for the modified LiFePO4 (170kWkg at a 400C rate and 90kWkg at a 200C rate) is two orders of magnitude higher” than typical lithium batteries. See http://www.gizmag.com/lithium-ion-battery-breakthrough-mit/11244/.

It should not cost a lot for an ordinary high-way gas station to add a 360kW charging station. Assuming it costs 50.000 USD per charging station you could add fast charging capability to 50000 gas stations for only 2.5 billion USD. This should more than cover all high-way gas stations in the US. Some firms are already offering 360kW charging stations for this purpose such as Thunder-sky. See http://www.thunder-sky.com/products_en.asp?fid=95&fid2=98

Hopefully the US, Japan, EU and China will soon legislate to require high-way gas stations to have at least one 360kW capable charger and that they can get a subsidy to set it up. That would be really helpful for the emerging EV and PHEV industry.


Considering that they are talking about a car with a range extender, charging stations should not an issue.


The best ev1 prototype was when they put a small 30KW Williams turbine in the boot of the car as a range extender. The only problem was the turbine cost $1 million. A 30 KW cogeneration Reinhardt Turbine piston turbine weighs only 30KG (including the generator) and it costs less than $500.

If GM takes this approach they will release a Volt for $12K instead of $40k. The battery pack only needs a few KW hours and inexpensive lead acid batteries.

Volt's with 65% efficient Reinhardt Turbine's could be part of a distributed smart-grid energy solution for the world. Why plug in when your 30KW generator can be more efficient than the utility's power plant?

Come on GM, let's change the paradigm! What is good for GM is good for America and the world in this situation.


GM made a huge bet on the Volt. But the bet is for high sales volumes with production optimized for lowest costs.

i.e. the standard model for US auto producers since 1910.

And they are making sure the the new platform and drivetrain will be usable across their product line.

e.g. building to EU standards as well as US.

Two concerns: batteries and warranties.

What about batteries? If they do not become available and affordable in high volumes then what could be salvaged from this huge investment?

Customers are also going to demand an impressive warranty. And they will expect a GM able to support it.

And a question for the masses. Will faster charging prove important in boosting sales?

With only a 40 mile electric range it seems to me that people simply won't interrupt their driving for even a ten minute charge.

But if charging at work or at home becomes the norm then it needn't be very fast.

Account Deleted

The fast charge capability of a battery for PHEV use is important because it enable the battery to do more regenerative braking. The electric motor in the Volt is much larger than in a normal hybrid (3 to 4 times) so it can also generate much more energy from regenerative braking. I don’t have the exact numbers but would not be surprised if the Volt can generate 100kW or more at max braking and that would destroy a non-fast charging battery. I fully agree that the fast charging capability of a PHEV otherwise is not really important but still nice to have.

However, for pure EVs it is not just nice to have but much more of a necessity for widespread use.

About the cost of the battery this is of cause a most important topic. I have observed the kWh price of lithium batteries drop from 1000+ USD in 2007 to now 500 to 600 USD per kWh. This is retail prices in the US for LiFePO4 with 2000 times cycle capability. For instance, Thunder-sky batteries at 600 USD per kWh see http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=4992 or China HiPower for about 500 USD per kWh http://www.cloudelectric.com/product_p/ba-lb-200-3.2.htm.

To repeat these are retail prices so the out of factory price must be considerable lower. I managed to get the number from Thunder-sky using babel translator of a Chinese webpage that has the information needed to see that out of factory cost for Thunder-sky batteries is 312,5 USD per kWh at most. This is what GM or others with their purchasing power can get it for today. See http://www.thunder-sky.com/home_en.asp?id=483&typeid=79&orderby=42

For a 100 miles range in an EV car you need about 20kWh of battery. This is 20*300= 6000 USD which is an affordable premium for most. But the range is unappealing unless you know that the EV can be fast charged at any high-way station. Pentagon could pay the 2.5 billion USD that it costs to get such a network started nationwide. Heavy duty long-haul trucking could also be done cheaper right now with these batteries than with 2 USD a gallon for diesel. But EV heavy duty trucks will not come until they know they can charge quickly at any high-way gas station.


The five-hour charge time on my car means that I almost always end up relying on gas for any trips out after work. If I could charge up at work, I'd still have a little bit left over when I got home so that I could do errands on electric drive. A ten-minute charge time at a filling station sounds pretty appealing to me--but I am guessing that it would be a pretty hard sell for the typical in-a-hurry consumer who is used to a sixty-second fillup on gas. I think that GM has miscalculated in one area: they should have spent a great deal more effort on light-weighting the car so that the battery pack could be smaller and hence quicker to charge. Even if they had to introduce a car that was a lot smaller--like a Chevette--that would only be a commuter car, it would have been better than having to have a monstrously-large battery pack.


I must reiterate SJC's comment:
"Considering that they are talking about a car with a range extender, charging stations should not an issue."

Yes, they should have made it more lightweight but don't forget this is an EV, with electric drive, and a range extending ICE...so, this thing can go far on only a little gas. If it only had a 20 mile electric range, it's a great vehicle.


Why not a small 1 or 2 cylinder turbodiesel engine instead of a petrol range extender?
Since the engine will only run to charge the battery it only needs to put out about 10-20kW. Add LPG or CNG injection (using diesel as a pilot) to the engine would allow home fillups of fuel as well as overnight recharging and would turn the vehicle into a backup generator and V2G system.

Abandon the corn ethanol madness and instead use sorghum biogas along with sewage biogas mixed with natural gas to provide transport fuels.

For the same land area biogas will take a car three times as far as ethanol
Biogas can make use of exisiting natural gas infrastructure

Overnight charge from nuclear plants with 2MW wind turbines close to major roads to provide fast charging infrastructure, localy produced biogas mixed with natural gas as the fuel of choice for range extenders.


There were two comments in this press release that I found irritating, though not at the level that Lutz used to induce. First of all, given an opportunity to deny that they are going to pull an EV1 crushing fiasco again, they dropped the ball, stating that selling or leasing the Volt are both options that they are considering. Way to win back the people are still pissed about the EV1 getting crushed after the leases ended.
Second, Patil of CPI/LG Chem stated that the cost per available kWh was down to $1000 and falling, for a total pack price for the Volt of $8000. Lauckner though used much more vague phraseology when he said the pack will be :many hundreds of dollars less: than the US$1,000 per kWh cited by CM... Perhaps Patil was talking about the cell price vs. the pack price, and it is early days, but $500 a kWh for a pack that should last 10-12+ years is a huge positive, and then to have it walked back to around $800 per kWh...
With regards to smaller engines, I think GM is right to start with an existing engine that may be a bit more powerful that what we will need. If the first Gen can't cruise at 65 or 70 mph after the Customer Depletion Point (GM has a real way with words) due to a hill or a head wind, the car magazines would trash the Volt. The Volt is the first ER-EV produced in substantial numbers, it has to be able to perform like an ICE, not creep up hills like an underpowered VW Vanagon.


It really does not matter what GM uses for a range extender since 78% of the users will not need it in their daily drive. Use the cheapest engine they have in their inventory. Same thing with super fast recharging, just not needed for 78% of the public.

If you fall outside this 78% range then perhaps the Volt is not for you.

If we are talking about a large 18 wheeler truck then the efficiency of the range extender genset is paramount.. these vehicles need to go hundreds of miles daily.

A 30 KW cogeneration Reinhardt Turbine piston turbine weighs only 30KG (including the generator) and it costs less than $500.

Excuse me.. is this wonder available yet? when can GM order 50,000 of them?..10-15 years?


I think I read that the Volt will do 80mph going uphill continuously on a 6% grade road, with a depleted battery. Those roads are rare in the US and are the max grade allowed.

The Vanagons with their 90hp engine were lucky to do 55 going uphill.

Personally I would be happy with 55mph in those conditions.


If the first Gen can't cruise at 65 or 70 mph after the Customer Depletion Point (GM has a real way with words) due to a hill or a head wind, the car magazines would trash the Volt. The Volt is the first ER-EV produced in substantial numbers, it has to be able to perform like an ICE, not creep up hills like an underpowered VW Vanagon.


The range of any vehicle will be extended if its mass can be reduced.

I have invented a way to make cars safer in collisions. It will allow a significant mass reduction in the doors, trunk, side pillars, and other chassis parts.

Please look at my website www.safersmallcars.com



"With only a 40 mile electric range it seems to me that people simply won't interrupt their driving for even a ten minute charge."

The 40 mile AE range was selected because hard data shows some 80% of commutes are UNDER this range. If you want uninterrupted driving Volt uses the freakin' genset! Buy a tank of E85! And, um, don't most people spend ten minutes filling a gas tank these days? Ten minutes is your issue??


sulleny: No ten minutes isn't my issue.

Clearly I was posing a question about unknown customer behaviour. Behaviour that will not become known until a lot of people are driving hybrids with forty mile electric range.

What will those people do? And what relative values will they assign to fast charging and various electric ranges such as 20, 40, or more miles?

Would they stop at around forty miles and recharge? I doubt it. I suspect they would just drive on using the ICE, complete their activities, and top off by charging overnight or at work where the car will be parked for several hours.

If that scenario is correct then buying a recharge at commercial stations may not become the norm and fast charging may not be highly valued.

Someone pointed out accepting fast charge helps in recovering energy during braking. I think capacitance will prevail for that. But that is all a technical and cost issue and may the better method win.

Contrary to your sneer I am quite aware the Volt has an ICE.


With regard to smaller engines falling short with possible lack of power you must consider the series hybrid power profile is unlike no other.

It happens that the conventional method to connect an internal combustion engine through a multi-ratio gearbox may be a good way to use an engine's torque but it is a very poor way to utilise its power, whereas series hybrids are primarily about power, not torque.

As an example, if road conditions produce a torque demand that exceeds what the conventional powertrain can handle - when using its most propitious gear - then the vehicle will slow until the torque demand falls back into balance with what the powertrain can provide.
The engine rpm cannot reach its max rpm where it develops max power so it cruises in what we call a torque stall condition. It's a situation that exists where the engine is producing perhaps 70% of its max power. That said it is not uncommon for less scientifically minded people to declare the vehicle powertrain to be underpowered.

The series hybrid allows its engine to spin up to max revs at any time thus allowing the powertrain to capture that extra 30% that was previously lost when using a manual gearbox.
As you accelerate using the gearchanges of a manual box you are persistently robbing the engine of achieving its max revs and therefore its maximum power. Tentatively I calculate that a 65Hp engine in a series hybrid will yield the same performance as a 100Hp engine coupled to a conventional manual transmission.

So if you're wondering what's this got to do with the price of rice, the difference is that the maximum torque from a manual transmission is constant for each gear.
On the other hand the torque from a series hybrid drive powertrain is not constant. As road conditions attempt to slow up a series hybrid, its torque will tend to increase commensurately in order to maintain constant power. As you might expect torque stall will occur at a much higher road speed or gradient than with a manual transmission.

Interestingly the Prius powertrain although not a complete series hybrid will display the effect of a constant power profile from 51mph through to 100mph.

In 2005, a Toyota racing team changed the transaxle ratio from 4.113 to something close to 3.00 and allowed the engine to 6000rpm and to develop about 91Hp. The vehicle with this engine was able to acheive 128 mph on the Bonneville Flats. Search this website for more details. Gives you some idea of what a 1.5L 4 cyl engine is capable of with the right powertrain.


The main reason gm can afford to spend so much on the volt is its basicaly the same exact work to be done on ALL thier future cars.

By 2040 every car will be erev bev or fuel cell and the volt is the prototype of all those.


Excellent point wintermane2000.

They only have to engineer this once to get the ball rolling. Afterwards, it will be fine tuning.

I predict that GM will be caught flat footed, having underestimated the demand for the Volt. A huge backlog will only drive up the price, which would be unfortunate. What we need is a very affordable EV (under 20K) to really get the EV revolution moving.


danm, I hope that you are right, that there will be a huge demand for the Volt at a net price of around $31,000+. I think if GM is still around they will sell all of their production in 2010-2011, but when the tax credits run out they will start to slow down. I hope that other makers and GM will be able to produce ER-EV's much more inexpensively due to the economies of scale.
But I think there will be two schools of low carbon cars for the near future, i.e. 2013-2015. There will be the ER-EV types that will use smaller 10 kWh to 20 kWh batteries to get unlimited range from a relatively inexpensive battery as pack prices drop from $700-$800 per total kWh to $250-$300 kWh. But they will be hindered by the weight and expense of needing the ICE generator. If someone can build a lightweight turbine, etc. that is powerful, lightweight and cheap, the ER-EV may end up being the car choice for the next 20-30 years.
Then there will be the BEV's, which will use 30-60 kWh packs to give reasonable range and rely on quick recharges to get back to 50-70% of the full kWh capacity. So if you have 50 kWh batteries, and you get 250 miles on the first charge, you pull in to a rapid recharge fuel station with 25 miles of range left in the pack and recharge in 10-15 minutes back to 190+ miles of range. So on a roadtrip you would have to pull over every 2 1/2 hours.
If you drive a lot of longer roadtrips, you would probably buy an ER-EV, if you drive mostly around town, you would probably find better utility in a BEV. The question is, how fast will the ICE generators inexpensively 'add lightness', and how fast will the price of kWh's drop? If the ICE can get lighter fast, and battery prices drop but don't go below $250 kWh, the ER-EV's will have a long run. If battery packs are built within 3 or 4 years at less than $250 a kWh, the BEV's will probably rule the road. But due to the systemic advantages and disadvantages of each, I wouldn't be surprised to see both hang on for quite a while, though one or the other will predominate.
I hope the economy holds on long enough for us to see this play out sooner, rather than later. I would love to see the US use 18m gallons a day of oil, then 16m, then 14m, while China and India use the same technology to reduce their own demand for oil, and then see what would happen to Venezuela, Saudi Arabia, Russia, Nigeria, the Sudan, Iran, etc. The US, Canada and Norway will end up producing enough for themselves and not take much of a hit. The oil thugs will take a huge hit. The problem though is that if the demand for oil goes down, so will the price, which means the ER-EV's and BEV's will have to get produced even cheaper and have to run even more efficiently to compete with ICE autos that are running on dirty oil that is cheap because most of us are using BEV's....
My head hurts...


...the difference is that the maximum torque from a manual transmission is constant for each gear.

I think this is very wrong, and your point (of series hybrid superiority) is based on it.

The purpose of shifting to lower gear going uphill is to increase torque at the (driven) wheels.
For the same engine rpm you vary torque at the wheels by changing gears.

The thing you're missing is engine efficiency vs rpm.
The nice thing about series hybrid is that the engine can be run at the rpm where it is the most fuel efficient, or where the genset combination (engine + generator) has the highest efficiency.



I may not remember correctly but I believe more than 1/2 of all oil used by the US is not related to transportation [too lazy to look it up right now] and only 1/4 of the oil we use is produced at home...therefore, even with the total displacement of oil as a fuel for transportation, we will still need to import oil. Maybe we can get 5Mbpd from Canada...but the "oil thugs" would definitely take a huge hit. Now, with such a huge hit, if they don't further develop and diversify their economies I see them devolving even more and staying just as difficult to deal with in the future.


If we really are on the down side of the peak oil curve then no need to worry about price of oil dropping. Once the US economy bounces back, oil prices will roar back. This will keep EV development on track.

Once the first EV's get on the market and people see the low maintenance, high reliabiliy (due to simplicity compared to ICE) the momentum will keep building.


Patrick, if you include trucking as transport, we use 66% of our oil on transport. If it is just light duty vehicles we are talking about, it is about 46-49% of our oil usage if memory serves, maybe 9-10m bbl a day for light duty vehicles. We produce 12.5m bbl a day, exporting 1.5m bbl, but our total oil use is 20.6m bbl a day. . So we produce and keep 11m bbl daily and import 9.5m bbl daily. There is no way we will completely stop using oil product for transport but if we could just start to trim the 10m bbl that go to LDV a bit, say reduce that 10m bbl to 8m, that would free up 2/80 (total world production is around 80m bbl/day) of the world production. None of the OPEC countries can be convinced to reduce their production so their would be an oil glut, at least at first, dropping oil prices. Then, a few years later, oil demand would go up as China says, forget conservation, give me cheap oil, and the price would go back up. I just don't want the Volt type vehicles to get marginalized by their own success at allowing the US to import less foreign oil.
danm, you are right about the Hubbert Peak Oil situation, but it will take years for the numbers to drop drastically, and if the Volt, and the Tesla S sedan, and the IMiev, and the Prius plug-in and the Ford electric car show up soon, I hope they will become a large enough portion of the total automobiles that maybe, maybe our oil use would go down more than the Peak Oil scenario will, allowing a glut to emerge. I want an oil glut to reduce oil cost, and rapidly growing ER-EV, BEV and PHEV sales. I want my cake and to eat it too! Mostly, though, I want to see less oil burned in the USA, and in the world.
And is it just me, or is there an echo in here?




Your production numbers are pretty far off so you convinced me to stop being lazy. Obviously you are mixing in numbers for REFINED product with CRUDE OIL and creating quite a bit of confusion for anyone reading your response.

US produced 5.4 million bbl/day 3/13/09(of crude oil)
US imported 9.2 million bbl/day 3/13/09(of crude oil)
US exported 0.029 million bbl/day 3/13/09(of crude oil)

Total product supplied for 3/13/09 is 18.8 million bbl/day(refined product). The difference in import versus export of refined product is around 1.4 million bbl/day. I am going to have to guess (without wasting time actually crunching the numbers) that the export products were created from oil purchased outside of the current supply inputs (maybe where the supply was drawn down) and thus the imports of refined product cannot really be directly weighted against the export of refined product - but pure speculation in order to make up the "missing" few million barrels per day. Also there are 1.4 million barrels/day of "blending" components used in making gasoline that could help to "balloon" the numbers so it appears that more barrels are used than supplied.




Hi Patrick, you are right, I was wrong on the amount the US produces. I re-read both my EIA docs and checked wiki and they both state that we consume 20.68m bbl of petroleum products daily, but that is about all I got right. They also state that the US produces between 8.4m bbl and 7.2m bbl of petroleum daily.
It is funny, my whole point was that I wanted to see our oil use drop due to the increasing supply of electrically powered cars and trucks, and I ended up searching the EIA for info I don't really care about.
So my point is: We use a shitload of gasoline derived from petroleum products in our cars and I hope that the Volt, and other BEV's and ER-EV's reduce that amount significantly. But even if half of the cars on the road are BEV's or ER-EV's it won't be a silver bullet because oil refined into gasoline used by light duty vehicles is less than half of the oil we use.




As long as the topic is future batteries:

"Spin Battery: Physicist Develops Battery Using New Source Of Energy"


Thought I would throw that in as an FYI.

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