Aug 02

Spark EV versus Volt Battery

 

By George S. Bower

Note – GSB told me he had an article for you today. Normally we’d run a Volt sales story, but we can break tradition and cancel that. Just kidding! (kdawg, those last two words mean j/k … j/k.). :) . Not that everyone doesn’t already know it, but Volt sold 1,788 units in July to Leaf’s 1,864. Calendar YTD, Leaf is up by 60 units at 11,703 sold. Comparing July 2013 to July 2012, Leaf’s doing really well and is up 371.9 percent over the mere 395 units it sold in July 2012 versus Volt’s 1,849 sold in July 2012. YTD compared to 2012, the Leaf’s tally is up 270.3 percent. Calendar YTD in 2012, Volt was at 10,666 units. This year Volt’s at 11,643 CYTD. In short: Volt is mildly ahead, and Leaf appears to be coming on stronger, but also, Nissan practically had no where to go but up.

Layout

 

We saw in another article presented here that the Spark EV co axial transmission offered some advantages relative to simplicity, weight and packaging compared to the Volt transmission. Could the Spark’s battery offer some advantages over the Volt battery as well?

We all know that the Volt uses a “T” pack configuration as shown in figure 1.

Slide1
 

The Spark battery has 336 prismatic shaped cells like the Volt only configured in a square box that fits under the rear seat and in and below the rear hatch storage area as shown in figures 2, 3 and 4.

Slide2
Slide3
Slide4
 

Battery Stats

 

A comparison of the Spark and Volt battery is presented in figure 5

Slide5
 

The Spark’s battery is rated at 21.4 kwh versus 16.5 for the Volt…….not surprising since the Spark is a pure EV designed to go 82 miles on a charge while the Volt is an extended range vehicle designed for 40 mile EV range.

Also not surprising is that the Spark battery pack is larger volumetrically at 133 liters versus 100 liters for the Volt and also heavier at 560 lb versus 435 lb for the Volt.

The Spark pack uses a much higher percentage of its rated capacity at 81 percent versus 65 percent for the Volt. This may be due to the robust nature of the packs Fe chemistry relative to number of charge cycles, tolerance to heat and tolerance to high charge rates. This tolerance to high charge rates shows up in the Spark’s ability to charge to 80 percent of full charge in 20 minutes while the Volt has no quick charge capability. Translated into C rate, we see the Spark’s battery can charge at 2.3 C…..pretty high by any automotive standard.

I mentioned ruggedness and tolerance to high charge rates and high temperatures as a virtue of Spark’s Fe chemistry.

Little known is that the Spark uses a much simpler cooling scheme than the Volt. As shown in figure 6, the Volt uses aluminum, liquid cooled plates between every other cell. The Spark however uses only 2 thermal exchange plates (separated by a thermal matt) located in the bottom of the battery box resulting in a simplified, lower cost and higher reliability design as shown in figure 7.

Slide6
Slide7
 

When looking at the Spark battery, one is tempted to say that the pack looks smaller than the Volt. We know it is larger than the Volt at 133 liters versus 100 for the Volt but it also has a much higher kwh rating so while the pack may be 33 percent larger in Volume it also has 60 percent more energy. So on a volume per kwh basis the Spark pack is actually smaller than the Volt. These figures are shown in figure 8.

Slide8
 

Which battery is better? There are trade off of course but personally I think the Sparks battery is better. It is more robust, can handle higher charge rates and has a simpler, lower cost cooling scheme.

I think this battery would make an excellent choice for Volt gen 2.0

What do you think?

Hat tip to WOT who mentioned the battery cooling in the tray via the GM-Volt forum.

This entry was posted on Friday, August 2nd, 2013 at 5:55 am and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

COMMENTS: 92


  1. 1
    nasaman

    +15

     

    Vote -1 Vote +1

    nasaman
     Says

     

    Aug 2nd, 2013 (6:07 am)

    I agree, George: I also think Spark’s battery, using newer, more robust Fe chemistry allowing simplified thermal control would make an excellent choice for Volt gen 2.0!*

    *Also, this battery should allow 5 seats, higher charging rates and longer AER in Volt gen 2.0!


  2. 2
    taser54

    +4

     

    Vote -1 Vote +1

    taser54
     Says

     

    Aug 2nd, 2013 (6:17 am)

    I think that Volt 2.0 will maintain its use of LG manufactured cells in its pack; however, I believe that GM will utilize the simplified cooling system found in the spark pack. This cooling design would also free GM from using the T-shaped battery pack configuration.


  3. 3
    xiaowei1

    +29

     

    Vote -1 Vote +1

    xiaowei1
     Says

     

    Aug 2nd, 2013 (7:01 am)

    I have been giving this a bit of thought. GM should not be touting a “gen 2″, they should be simply changing the model year number making incremental changes along the way (big or small). why? many people are finical about technology and wanting the latest – this also keeps resale value. I for one, am waiting for “gen 2″ to purchase knowing it is “imminent”. I have been led to believe there will be significant changes all round in just about every aspect of the car. this may mean upgraded electronics, new purpose build engine, more HP from the electric motor, longer lasting battery, much cheaper price… etc… why would I not want to wait? the mentality that comes with this is “yes, you can buy now, but if you just wait a year, your product will be twice as good.” this is not like buying when the volt just came out, we are 5 years in and the new one is almost here… expectation of future product upgrades has killed off companies in the past as people wait for the new technology. so GM should not be saying “gen 2″ is coming, they should be saying, 2014, 2015, 2016, etc… model is coming. I hope that makes sense.


  4. 4
    Dave G

    +13

     

    Vote -1 Vote +1

    Dave G
     Says

     

    Aug 2nd, 2013 (7:22 am)

    xiaowei1: the mentality that comes with this is “yes, you can buy now, but if you just wait a year, your product will be twice as good.”

    I doubt Volt 2.0 will be much better. In fact, the extra weight in the current Volt makes it ride like a dream. A lighter, more efficient Volt may not ride as smoothly.

    The problem with the current Volt is that it costs too much to build. The major aim of Volt 2.0 is cost reduction. GM wants to Volt to become profitable. So I doubt Volt 2.0 will have a more powerful motor, or significantly more electric range, as this would increase cost.

    In the meantime, GM is offering $5000 cash incentives on 2013 Volts, and dealers are adding serious discounts on top of that. So as a consumer, I don’t think there’s much reason to wait.


  5. 5
    Loboc

    +14

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Aug 2nd, 2013 (7:37 am)

    Put either battery configured as 120 true AER in an Impala and I’m in. EV’s just aren’t there yet for large geographic area cities like the metroplex (DFW).

    I’m at 60-80miles per day a lot. I burn gas almost every day in my Volt. Heck, just sell me 50% more battery!


  6. 6
    Fred

     

    Vote -1 Vote +1

    Fred
     Says

     

    Aug 2nd, 2013 (8:18 am)

    xiaowei1,

    That’s why it’s best to lease instead of buy.


  7. 7
    Jackson

    +2

     

    Vote -1 Vote +1

    Jackson
     Says

     

    Aug 2nd, 2013 (8:51 am)

    Loboc: Put either battery configured as 120 true AER in an Impala and I’m in. EV’s just aren’t there yet for large geographic area cities like the metroplex (DFW).

    The Atlanta metro is also very large, but I see plenty of EVs (mostly LEAFs). Do you drive everywhere in your metroplex on a daily basis? Most people in Atlanta have their paths from work to home, and do shopping etc at points in between. Unfortunately, the Atlanta metro is a fairly good example of “Generica,” and you can find pretty much anything you want within 2 – 3 adjacent neighborhoods/communities. There is the occasional downtown trip for entertainment venues, or cross-metro for restaurants, outlets etc; but that’s what a range-extender is for!

    I’m at 60-80miles per day a lot. I burn gas almost every day in my Volt. Heck, just sell me 50% more battery!

    So you’re getting 80 – 90 mpg on those days. Enjoy!

    That’s not to say that I wouldn’t love 50% more AER … perhaps GM can provide more as they lower costs; today’s article offers some hope. 50% seems unlikely in the near term, though.


  8. 8
    kdawg

    +4

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (9:03 am)

    Would the Spark’s battery work in the Volt’s application? I thought it was different chemistries for different applications? Thing’s like C-rate change.

    Let’s say it would. How far could the Volt travel on the Spark’s battery? The Volt weighs 800lbs more than the Spark EV, but it is more aerodynamic. If we could use just 1/2 of the Spark’s battery, that would reduce the weight of the Volt by 155lbs and still maintain the 40 mile range (maybe even more). Then we need to look at cost. If only we knew the cost of these two packs, but judging on the price difference between the Spark EV and the Volt, I have to think the Spark’s battery tech is cheaper. So using 1/2 the pack of the Spark EV would also reduce the price of the Volt.

    I’m like most Volt owners and want more EV range. Maybe GM should offer the Volt with either 1/2 the Spark EV pack, or a full pack version. So you could buy the 40mile/day Volt or the 80mile/day Volt. This would allow the Volt to compete with the BMW i3 on the AER range.


  9. 9
    Jackson

    +4

     

    Vote -1 Vote +1

    Jackson
     Says

     

    Aug 2nd, 2013 (9:15 am)

    nasaman: this battery should allow 5 seats [ ... ] in Volt gen 2.0!

    Seating for 5 is an often-mentioned wish, but wouldn’t be that useful in a car of this size, IMO (unless you have 3 kids). I’ve had 3-across back seating (theoretically) in several small cars, but needed it only rarely (3 adult passengers were never comfortable for long). Let Voltec get even modestly larger, and the 3-across rear seat will be a bigger* deal.

    * … so to speak. ;-)


  10. 10
    Tim Hart

    +3

     

    Vote -1 Vote +1

    Tim Hart
     Says

     

    Aug 2nd, 2013 (9:18 am)

    GM definitely needs to produce a Volt that affords them a profit otherwise they have no incentive to spend money educating the public about how great and unique it is. And the vast majority of the public still doesn’t understand that.


  11. 11
    Loboc

    +7

     

    Vote -1 Vote +1

    Loboc
     Says

     

    Aug 2nd, 2013 (9:35 am)

    nasaman,

    Jackson,

    I’d rather have two good-sized seats than three jump seats in the back. Volt could use about 3″ more legroom back there though.


  12. 12
    George S. Bower

    +1

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (9:40 am)

    kdawg:
    If only we knew the cost of these two packs,

    There is another reason why the Spark pack should be lower cost/kwh.

    The current Volt battery consists of a multitude of plastic resin pieces that form the main cooling passages (or large tubes) that run down the side of the battery. These tubes then feed the aluminum plates with the Dexcool liquid coolant. From what I remember from the article I read (and couldn’t find) these plastic resin pieces are a super high tolerance “push together” fit.

    With the simple Spark design, these plastic resin frames that push together are totally eliminated.

    I wish I could have found the article on this aspect of the Volt design.

    If any of you can find it please post it.


  13. 13
    Dave86

    +11

     

    Vote -1 Vote +1

    Dave86
     Says

     

    Aug 2nd, 2013 (9:41 am)

    We’ve had a lot of battery articles here at gm-volt.com recently, and they have been greatly appreciated. (One of these 400whr/kg breakthroughs is going to find its way into an EV…)

    Thanks, George, for a terrific write-up.


  14. 14
    Ziv

    +2

     

    Vote -1 Vote +1

    Ziv
     Says

     

    Aug 2nd, 2013 (9:42 am)

    Seating for 5 in a Volt is nice, but cheaper and roomier is what is really important.
    Offer an MPV5 for the people that need seating for 5 but offer a Volt Gen II using the D2xx platform with a bigger back seat and choices on whether you get a 40 mile AER or a 60 mile AER.
    And punch up the 0-60 times a bit, too, while you are at it.


  15. 15
    Jackson

    +1

     

    Vote -1 Vote +1

    Jackson
     Says

     

    Aug 2nd, 2013 (9:58 am)

    Ziv: Offer an MPV5 for the people that need seating for 5

    Is this what the “5″ in MPV5 stands for?


  16. 16
    Jackson

     

    Vote -1 Vote +1

    Jackson
     Says

     

    Aug 2nd, 2013 (10:07 am)

    With a 3-across rear seat, wouldn’t the Volt pack of today be split into two? You’d have the base of the “T” ahead of the rear seat, and the cross of the “T” separated at the rear. If there is a crucial reason for staying with the LG cells, perhaps the Volt Gen II could “split the difference,” offering LG Chem in one and A123 Shenzou in the other.

    This would be far from ideal, unless the series/parallel can be adjusted to provide the same voltage for both packs, and/or a common amperage charge rate for both is adopted (engineers please weigh in).

    You’d want to do this to increase range a bit while lowering some cost if you would be limited by low availability of A123 cells (which could happen if the Spark EV really takes off). Hopefully A123 supply is good, and the added complexity won’t be necessary; but this represents a possible intermediate solution if needed.

    If both packs were designed to be identical in size, full A123 operation for a future model could be a “push-pull click-click” modification (you’d likely change out the charger, too).


  17. 17
    Steve-o

    +4

     

    Vote -1 Vote +1

    Steve-o
     Says

     

    Aug 2nd, 2013 (10:11 am)

    I thought I heard that the D2XX platform would be 5 inches longer, so gen 2 will either have more leg room in back or more room for a larger battery without the T shape. It’s hard to imagine a whole Spark battery going in there, because there still has to be a gas tank, 12V battery, and DC-to-DC converter. With two power plants and 5 radiators, the area under the hood is already packed, so it seems like that all still has to go in back.

    The cooling layer under the battery is surprising. I missed it in the forums. That looks fine for heating the battery, but how do you cool the top of a hot battery with the cooling system underneath it? The electrolyte doesn’t circulate in the cells, does it?


  18. 18
    stuart22

    +5

     

    Vote -1 Vote +1

    stuart22
     Says

     

    Aug 2nd, 2013 (10:14 am)

    I agree with Ziv about upping road performance. If there’s any lesson Tesla has taught us, it is that the quickest way to creating an iconic legend about yourself is to kick the pants off of the top performing models of iconic brands like Mercedes and BMW. Those YouTube videos of a Model S unexpectedly outdragging a growling M5 went viral, shutting the door on any doubts that the Model S could ever be a serious contender in the auto market.

    There will be more EVs hitting the market between now and when the Gen Two Volt rolls out. Until then, if Chevy wants to keep people’s attention on the Gen One Volt they need to create some enthusiasm among the buying public – a sporty performance model could do that. A Volt sports sedan with better acceleration, a bit quicker steering and slightly tuned suspension – and of course, paddles for controlling regen – would fill the bill.


  19. 19
    Jackson

    +1

     

    Vote -1 Vote +1

    Jackson
     Says

     

    Aug 2nd, 2013 (10:23 am)

    stuart22: if Chevy wants to keep people’s attention on the Gen One Volt they need to create some enthusiasm among the buying public – a sporty performance model could do that. A Volt sports sedan with better acceleration, a bit quicker steering and slightly tuned suspension – and of course, paddles for controlling regen – would fill the bill.

    Cadillac is making it, it’s called the ELR. Sportiness comes at the cost of AER though, and there will be only 30 miles. IMO this makes it a toy for those who can afford it; and most of those would spring for the model S.

    A sporty Volt should probably wait until there is more battery capacity at lower cost. Hopefully it would get more than 40 miles on electricity, which would translate to over 55 in an ‘eco’ mode.

    I find ‘sport mode’ to be more than adequate, but I’m not a sports car guy. I use the mode rarely, and my wife not at all; the big deal for us is electric range. Perhaps this should be the standard Volt, leaving ‘sportiness’ up to the driver (which you can do today, to a degree).


  20. 20
    taser54

     

    Vote -1 Vote +1

    taser54
     Says

     

    Aug 2nd, 2013 (10:39 am)

    George S. Bower,

    Dana provides the cooling plates for the volt battery http://ev.sae.org/article/9506

    Now I stumbled across this article about a cooling plate that looks similar to the one used by the spark
    http://techon.nikkeibp.co.jp/english/NEWS_EN/20130527/283866/


  21. 21
    kdawg

    +4

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (10:44 am)

    Jackson,

    Things like “seating for 5″, or “0-60 in 6 seconds” are not things people use every day (or at all). But they are selling points and metrics people use to judge cars. People want to know that if for some reason, no matter how remote, they have that function/ability. That’s why the range extender is in the Volt. Many people don’t use it, but it’s comforting to know it’s there. Anything less than a worse-case what-if scenario is considered a compromise by many buyers.


  22. 22
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (11:11 am)

    taser54:
    George S. Bower,

    Dana provides the cooling plates for the volt battery http://ev.sae.org/article/9506

    Now I stumbled across this article about a cooling plate that looks similar to the one used by the spark
    http://techon.nikkeibp.co.jp/english/NEWS_EN/20130527/283866/

    good find.
    Now if we could find the article about the Volts plastic resin push together frames we’d have it.


  23. 23
    Noel Park

    +3

     

    Vote -1 Vote +1

    Noel Park
     Says

     

    Aug 2nd, 2013 (11:32 am)

    Loboc:
    nasaman,

    Jackson,

    I’d rather have two good-sized seats than three jump seats in the back. Volt could use about 3″ more legroom back there though.

    #11

    i agree. +1

    I have had my Volt for well over 2 years and I have NEVER had 4 people in it. But it’s pretty cramped for that 3rd person in the back


  24. 24
    Noel Park

    +4

     

    Vote -1 Vote +1

    Noel Park
     Says

     

    Aug 2nd, 2013 (11:33 am)

    Dave86: Thanks, George, for a terrific write-up.

    #13

    Second the motion. +1


  25. 25
    pjkPA

     

    Vote -1 Vote +1

    pjkPA
     Says

     

    Aug 2nd, 2013 (11:54 am)

    So how many of these “Leaf” sales are in Japan? .. where the Volt costs $80,000!


  26. 26
    Mark Z

    +1

     

    Vote -1 Vote +1

    Mark Z
     Says

     

    Aug 2nd, 2013 (12:00 pm)

    George, Thank you for the great graphics. I like the front to back balance of motor and battery in the Spark. Now, with the 95 CU rating of Impala, GM should start designing a large luxury Impala Volt for high AER around town and total EV performance across the country with a powerhouse of a motor/generator. GM could add some 120/240 volt electrical outlets to power the house!


  27. 27
    Evan

    +1

     

    Vote -1 Vote +1

    Evan
     Says

     

    Aug 2nd, 2013 (12:08 pm)

    *Also, this battery should allow 5 seats, higher charging rates and longer AER in Volt gen 2.0!

    Or more likely, relatively the same AER, with more cargo room, and at a lower price.


  28. 28
    Evan

    +1

     

    Vote -1 Vote +1

    Evan
     Says

     

    Aug 2nd, 2013 (12:08 pm)

    pjkPA:
    So how many of these “Leaf” sales are in Japan? .. where the Volt costs $80,000!

    The sales numbers listed are in the USA.


  29. 29
    kdawg

    +4

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (12:23 pm)

    Mark Z: GM should start designing a large luxury Impala Volt

    I agree, but not an Impala. In fact, not any existing GM cars. It should be a stand-alone, purpose-built EV.


  30. 30
    pjkPA

     

    Vote -1 Vote +1

    pjkPA
     Says

     

    Aug 2nd, 2013 (12:23 pm)

    Good article…

    two questions…
    What is the weight distribution for the spark… the Volt is 50/50.
    Cooling system… which one would you want in very hot weather? Or when you need a quick warm up in very cold weather?


  31. 31
    George S. Bower

    +3

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (12:26 pm)

    Jackson: Cadillac is making it, it’s called the ELR.

    I’d really like to see GM build a 200 mile range Tesla fighter.
    Might as well make it a Model X fighter.
    Scale up the Spark EV coaxial trans and put one front and back for AWD.
    Put the batteries in the floor and use the same spark EV cooling mat system.
    Then bring all light weight weapons to bear from their latest and greatest Corvette.
    Awesome.


  32. 32
    Zeede

    +1

     

    Vote -1 Vote +1

    Zeede
     Says

     

    Aug 2nd, 2013 (12:30 pm)

    Steve-o: The cooling plates are on the bottom, but there are aluminum fins that run up between each cell that are connected to the cooling plates. Since each cell is relatively thin, this should suffice.


  33. 33
    volt11

    +3

     

    Vote -1 Vote +1

    volt11
     Says

     

    Aug 2nd, 2013 (12:41 pm)

    If they get the CS-mode mileage up to 50mpg, they could go with a smaller gas tank, like 6 gallons. That leaves more room for battery.

    I don’t see the big deal about adding room for 5. No matter what, you couldn’t get 3 adults in back with anything resembling comfort. I also like the rear console style. However, I DO want more legroom in back. To me the Volt (especially in an SS version) has the potential to be a nice alternative to the Porsche Panamera plug-in hybrid at half the cost. (Really that’s what the ELR should have been, only at maybe 2/3 the cost.) I’d rather see the Volt get nicer instead of cheaper. Make a plug-in hybrid Cruze to cover the lower end of the market. Add an i3 style range extender option to the Spark EV. Finally add a CUV version of the Volt. Those 4 cars could make a great Chevy green lineup that’s unsurpassed in the industry. (Not to leave out the eAssist versions of the Malibu and Impala, but those in the real world are sub-30 mpg ICE cars.)


  34. 34
    ziv

    +7

     

    Vote -1 Vote +1

    ziv
     Says

     

    Aug 2nd, 2013 (12:41 pm)

    I drive myself and 3 other Realtors on tour every Tuesday, and I have my clients in the car every week. If there are 4 of us in my Volt, and the other front seat rider is over 5’10″, I put the most petite person in the back behind me and move the seat up around 5″. It isn’t comfortable for me, but it is ok for a woman that is less than 5’4″ or so.
    I could REALLY use a few more inches of rear seat leg room in the next Volt. After that, I think the charger HAS to be 6.6 kW and I am good. I really hate to stop for lunch, have my car on a L2 charger for an hour, and only pick up 9 miles of AER. On busy days, the 3.3 kW charging rate is a real disappointment.
    I would love to have more assertive acceleration, but it isn’t a deal killer if it is the same as my current Volt or just a little faster.

    Noel Park: #11

    i agree.+1

    I have had my Volt for well over 2 years and I have NEVER had 4 people in it.But it’s pretty cramped for that 3rd person in the back


  35. 35
    Steve-o

     

    Vote -1 Vote +1

    Steve-o
     Says

     

    Aug 2nd, 2013 (12:45 pm)

    Zeede:
    Steve-o:The cooling plates are on the bottom, but there are aluminum fins that run up between each cell that are connected to the cooling plates.Since each cell is relatively thin, this should suffice.

    Thanks. The cooling fins are the part I had missed before. That sounds like it could work.


  36. 36
    kdawg

    +1

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (12:47 pm)

    George S. Bower: I’d really like to see GM build a 200 mile range Tesla fighter.

    Me too, but I always wonder what the public wants. What’s important to each buyer? 0-60mph time? All electric range? Overall range? Price?

    I made the spreadsheets below comparing all of the plug-in vehicles out now. If you can assign a weight to each criteria, it may help you in choosing which plug-in to buy. Someone with more free time and who’s good at web-page design should make a “Help Me Choose A Plug In” webpage, where people could place a priority on each metric from 0-10 and it would calculate the plug-in that most closely matches their criteria. (I did not do include cargo space or seating… not enough time)

    (this pic may show up too small so I included the direct link as well. Or you can go to kdawg.com and choose the “Compare” tab at the bottom)

    http://i901.photobucket.com/albums/ac211/kdawg2011/Comparison_Plugins_zps785145dd.jpg

    Comparison_Plugins_zps785145dd.jpg


  37. 37
    DonC

    +1

     

    Vote -1 Vote +1

    DonC
     Says

     

    Aug 2nd, 2013 (12:50 pm)

    Great write up George. Nice pick up about the cooling.

    Technically I think the claim that the Spark pack has 60% more energy by volume is dubious. You get that by using “usable” energy, but you want to use total energy. It would be easy enough to use 80% of the Volt pack. You would just have to be prepared to see your EV range drop over time. The systems are too different to compare the way you’re doing it. The only realistic comparison would be based on total capacity.

    As you can see from the specs, the A123 cells are less energy dense (this is for mass as is customary) but deliver more power. No surprise here. They are also safer.

    However, we don’t know what the current generation of LG Chem cells are like. We do know that they will probably use the magnesium layer-layer technology from Argonne Laboratories, which will significantly increase energy density and robustness of the cells.

    I also think that some of the cooling/heating and general coddling of the battery pack was unnecessary. I’ve always said that the first generation Volt would be the best built because we’d see a lot of belts and suspenders.


  38. 38
    Computer-codger

    +1

     

    Vote -1 Vote +1

    Computer-codger
     Says

     

    Aug 2nd, 2013 (12:50 pm)

    Another outstanding article, George.


  39. 39
    kdawg

    +1

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (12:55 pm)

    DonC: Technically I think the claim that the Spark pack has 60% more energy by volume is dubious. You get that by using “usable” energy, but you want to use total energy. It would be easy enough to use 80% of the Volt pack. You would just have to be prepared to see your EV range drop over time.

    Also, you are never going to fully use the Spark EV pack (and strand yourself), but you will consistently use the Volt’s entire usable energy. All depends if the Spark EV battery is used with a RE or not.


  40. 40
    DonC

    +2

     

    Vote -1 Vote +1

    DonC
     Says

     

    Aug 2nd, 2013 (1:11 pm)

    kdawg: Me too, but I always wonder what the public wants. What’s important to each buyer? 0-60mph time? All electric range? Overall range? Price?

    Price always matters. For a pure EV or even an EREV, range will always matter. After that it depends on what you’re selling. I doubt buyers for the the MB S Class or BMW 7 Series or the Chevy Impala know what the 0-60 times are. Surely a Prius buyer doesn’t know, or, if they do, they don’t care. It depends on what you’re trying to sell.

    Also what people say they want and what they’ll buy aren’t always the same. We’ve seen tons of comments here about how people want an electric SUV/CUV. Well there is one. It’s the Toyota RAV4-E, which happens to sport a drive train made by Telsa, a 7 second 0-60 time, and an EPA range of over 100 miles. Should be a hot number. However, Toyota has to take out all the stops to sell 100 of them a month. My take is that this failure has resulted from using the last generation body, which makes the RAV4-E look old and dowdy.

    Which brings us back to the question of what customers want. Some of that depends on what you have to work with. With electrics you have quite a bit. They can easily be faster and they will always be smoother and quieter than ICEs. Rather than going the eco route I think GM would get higher transaction prices by making a hot looking four door (the ELR shows they know how to do this) with a sub 6 second 0-60 time. That means a bigger motor and cells which are more power dense or more cells. Both mean more weight but Tesla has proved that if there is one thing people don’t care about it’s mass. They can forget about the range extender — no one is going to care much about that either — and market it with the Great Taste/Less Filling approach — speed AND luxury at an affordable price (affordable being relative).


  41. 41
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (1:29 pm)

    Zeede:
    Steve-o:The cooling plates are on the bottom, but there are aluminum fins that run up between each cell that are connected to the cooling plates.Since each cell is relatively thin, this should suffice.

    No this is not my understanding. The cooling all comes from the bottom.
    There are no cooling plates in between cell in the Spark battery system.

    This all comes from WOT
    start reading at #21
    http://gm-volt.com/forum/showthread.php?61386-Spark-battery-geometry-for-Volt&p=803369#post803369


  42. 42
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (1:41 pm)

    DonC:

    Technically I think the claim that the Spark pack has 60% more energy by volume is dubious.

    If you look at the last figure, the volumetric energy density is only 20% better.
    Also I would submit that using “usable” kwh instead of pack rating is the ONLY fair way to rate the pack. It all has to do with cycle life. If you don’t know the cycle life you don’t know anything. You might have a great looking battery based on total pack kwh’s but if the cycle life is so bad you have to oversize the battery by a factor of 2 then the rating based on total pack kwh means nothing.

    One arguement that I might believe though is that the Volts battery is way overdesigned compared to the Spark—-ie that it has enough life in it that we could increase DOD.


  43. 43
    George S. Bower

    +1

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (1:45 pm)

    Computer-codger:
    Another outstanding article, George.

    Thanks computer codger and all others that made compliments. Everyone should know that I don’t make any money doing this. I only do it because I love it. It’s really engineering oriented and it excercises the engineering part of my brain which is good….not to mention that I’m an EV nut.


  44. 44
    Charles509

    +5

     

    Vote -1 Vote +1

    Charles509
     Says

     

    Aug 2nd, 2013 (2:03 pm)

    I had a small investment in A123 before their bankruptcy and subsequent sale to the Chinese corporation,Wanxiang, so I have followed them closely. A123 was one of the finalist for the supplier of the Volt battery. I believe that GM did not select them because they were a new company and there were concerns about their reliability. I guess some of their concerns were justified in the light of the manufacturing problems at their new plant which famously caused battery failures for Fisker. But, their has never been much doubt that A123 battery nanophosphate lithium ion battery technology was superior to all others at the time. Their nano phosphate EXT technology is even better at temperature extremes, and this may be the battery technology used in the Spark EV. Hopefully, A123′s battery will be used in the Gen. 2 Volt (2015).

    Envia Systems, which GM has invested in, has demonstrated batteries with 3x the energy density of the current batteries, so these could also appear in a Gen. 2 Volt.

    Either way, it’s an exciting time to be an electric car enthusiast!


  45. 45
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (2:16 pm)

    George S. Bower: Everyone should know that I don’t make any money doing this.

    LOL, I’ve gotten rich off of posting at GM-Volt.com. (If you count all the time at work I spend typing away here) :)


  46. 46
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 2nd, 2013 (2:18 pm)

    Charles509: Hopefully, A123′s battery will be used in the Gen. 2 Volt (2015).
    Envia Systems, which GM has invested in, has demonstrated batteries with 3x the energy density of the current batteries, so these could also appear in a Gen. 2 Volt.

    I can’t see GM dumping LG since they just built that new plant in Holland, MI. I would expect LG licensing the technology from Envia, and creating some new battery configuration.


  47. 47
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (2:37 pm)

    kdawg: I can’t see GM dumping LG since they just built that new plant in Holland, MI.I would expect LG licensing the technology from Envia, and creating some new battery configuration.

    I was somewhat concerned about the plant as well if they got dumped. We don’t need any more fodder for the unbelievers.

    re: making money..me thinks maybe you were being sarcatic. Well maybe ClarksonCote is making some money selling inverter systems.


  48. 48
    Robert Pyke

    +1

     

    Vote -1 Vote +1

    Robert Pyke
     Says

     

    Aug 2nd, 2013 (2:40 pm)

    Note that that in another posting it is reported that LG Chem are going to expand the number of lines at the Holland MI plant by September 2015. They must have some commitment from GM in order for them to say that?


  49. 49
    taser54

     

    Vote -1 Vote +1

    taser54
     Says

     

    Aug 2nd, 2013 (3:37 pm)

  50. 50
    Noel Park

     

    Vote -1 Vote +1

    Noel Park
     Says

     

    Aug 2nd, 2013 (3:40 pm)

    kdawg: LOL, I’ve gotten rich off of posting at GM-Volt.com.(If you count all the time at work I spend typing away here)

    #45

    Yeah, I figure that the “Toyota Boys” are the only ones who make any money, LOL. +1


  51. 51
    Streetlight

     

    Vote -1 Vote +1

    Streetlight
     Says

     

    Aug 2nd, 2013 (4:03 pm)

    George S. Bower: One arguement that I might believe though is that the Volts battery is way overdesigned compared to the Spark—-ie that it has enough life in it that we could increase DOD.

    Hi George: Well done. Interesting finding today’s topic about the SPARK after going through today’s Design News’ daily e-mail newsletter ‘DN Daily’ which features a review of 18 various EV models’ high voltages. Your SPARK-VOLT comparison table’s spot on.

    Note the SPARK’s voltage is a tad over VOLT—369 VDC…360 VDC respectively. Voltage must be factored in power ratings. Now the DN Daily feature underscores how traction battery voltages are increasing to benefit motor design and improve power dissipation. (LEAF runs 365 VDC; where Toyota’s Prius PHV plug-in hybrid uses a 650V electrical architecture. Source: DN Daily Aug 2, 2013)

    http://www.designnews.com/author.asp?section_id=1366&dfpLayout=blog&dfpPParams=ind_184%2Cindustry_auto%2Cbid_318%2Caid_266061&doc_id=266061&image_number=1

    We touched on the issue of ‘overdesign’ some time ago. Hardly is VOLT’s battery pack anything ‘over-design’. The proof is VOLT’s near-spotless battery trouble record (vs. total VOLT miles) Indeed, SPARK’s battery is in every sense a progeny of VOLT’s battery design.

    I believe GM has VOLT 1.1 capable of 50 AER/50 mpg in the bag. Furthermore, I believe the COMBO SAE high speed charger 80%/20 min is not only a game changer, but a necessary feature GM should endeavor as standard equipment for all presents designs.


  52. 52
    George S. Bower

    +1

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (4:04 pm)

    taser54,

    wow great find, thx

    Here are the plastic resin “repeating frames” that have been eliminated in the Spark design. Note that these frames form a manifold to distribute water to the cooling plates between each cell.

    voltbatteryrepeatingframes1_zpse2336110.jpg

    voltbatteryrepeatingframes2_zpse5c43f5c.jpg


  53. 53
    Richard

    +2

     

    Vote -1 Vote +1

    Richard
     Says

     

    Aug 2nd, 2013 (4:59 pm)

    The Spark battery certainly should be superior to the Volt’s. It’s 3+ years newer tech and experience.

    I see no reason why the Spark’s prism packs couldn’t be used in the Volt’s form factor; including the new cooling schema.


  54. 54
    HiFlite

     

    Vote -1 Vote +1

    HiFlite
     Says

     

    Aug 2nd, 2013 (4:59 pm)

  55. 55
    HiFlite

     

    Vote -1 Vote +1

    HiFlite
     Says

     

    Aug 2nd, 2013 (5:00 pm)

    BTW, I thought the Volt’s battery could also be heated via a heat exchanger in the ICE cooling circuit. Is this notion incorrect?


  56. 56
    ClarksonCote

     

    Vote -1 Vote +1

    ClarksonCote
     Says

     

    Aug 2nd, 2013 (5:40 pm)

    George S. Bower:

    re: making money..me thinks maybe you were being sarcatic. Well maybe ClarksonCote is making some money selling inverter systems.

    Haha, hardly. It’s more an interesting exercise than a money maker. There just isn’t the volume to make up for the basic costs of the business (like insurance).

    But maybe there will be one day, with increasing volumes of EV’s on the road.


  57. 57
    George S. Bower

    +1

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (5:51 pm)

    HiFlite:
    BTW, I thought the Volt’s battery could also be heated via a heat exchanger in the ICE cooling circuit. Is this notion incorrect?

    Yes,
    the Volt’s battery can only be heated via a resistive element.
    WOT wrote a great article on the Volt’s heating and cooling systems:
    http://gm-volt.com/2010/12/09/the-chevrolet-volt-coolingheating-systems-explained/


  58. 58
    DonC

     

    Vote -1 Vote +1

    DonC
     Says

     

    Aug 2nd, 2013 (6:30 pm)

    George S. Bower: It all has to do with cycle life. If you don’t know the cycle life you don’t know anything.

    But the cycle life OF THE PACK is determined by the number of cells. Double the number of cells and, for a given number of miles, you halve the cycles. Also note that the Spark comes with an 8 year 100,000 mile warranty but the Volt has to come with a 10 year 150,000 warranty. That difference could influence the percent of the pack you use.

    When calculating energy density either by volume or mass the only real way to do it is based on total not usable capacity.


  59. 59
    Steve-o

     

    Vote -1 Vote +1

    Steve-o
     Says

     

    Aug 2nd, 2013 (6:31 pm)

    George S. Bower: No this is not my understanding. The cooling all comes from the bottom.
    There are no cooling plates in between cell in the Spark battery system.

    OK, now I’m confused again. Heat rises, and the only cooled surface of the battery is on the bottom. The Spark battery isn’t thin heightwise, so how is this type of cooling effective? Why doesn’t half of the cell volume bake? Is the electrolyte such a great thermal conductor that cooling fins aren’t necessary, or is the heat in the battery generated exclusively on the bottom?


  60. 60
    HiFlite

    +1

     

    Vote -1 Vote +1

    HiFlite
     Says

     

    Aug 2nd, 2013 (6:50 pm)

    ^ Heat rises only in the case of a temperature difference across a convective medium (water, air, etc). The Spark looks to be conductively cooled. (Conductive in the sense of a material moving heat thru itself). There is no up or down with conductive or radiative cooling.


  61. 61
    nasaman

     

    Vote -1 Vote +1

    nasaman
     Says

     

    Aug 2nd, 2013 (7:18 pm)

    DonC: …”Double the number of cells and, for a given number of miles, you halve the cycles”…

    Don, this makes no sense —my many years of experience with 15+ year batteries makes me absolutely sure that the number of cycles before overall battery performance deteriorates doesn’t matter —whether a battery has FIVE cells or a THOUSAND cells! The only mitigating factor is, of course, that the more cells a battery has, the less likely that cell failure(s) will cause a total failure
    of the entire battery. If you disagree, please explain… (maybe it’s just semantics?)


  62. 62
    George S. Bower

    +2

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 2nd, 2013 (7:53 pm)

    Steve-o,

    Your intuition is correct.
    From a purely heat transfer POV the Sparks system is inferior.
    The only explanation is that the Sparks battery chemistry has a higher tollerance to temperature. So you don’t need such a perfect (expensive) system.


  63. 63
    Steve-o

    +1

     

    Vote -1 Vote +1

    Steve-o
     Says

     

    Aug 2nd, 2013 (8:35 pm)

    George S. Bower:
    Steve-o,

    Your intuition is correct.
    From a purely heat transfer POV the Sparks system is inferior.
    The only explanation is that the Sparks battery chemistry has a higher tollerance to temperature. So you don’t need such a perfect (expensive) system.

    Thanks, and, as HiFlite said, the Spark must be cooled conductively, indicating that the cells are at least good enough thermal conductors to get the job done, along with an apparently wider temperature tolerance. One way or the other, I’m sure the GM engineers didn’t overlook anything obvious. I just wondered how the physics worked out.

    We have often said the Volt is over-engineered. This must be just one example of that.


  64. 64
    DonC

    +2

     

    Vote -1 Vote +1

    DonC
     Says

     

    Aug 2nd, 2013 (10:15 pm)

    nasaman: If you disagree, please explain… (maybe it’s just semantics?)

    Battery cells degrade with every charge/discharge cycle and cells are rated for how many cycles they can go through before EOL. For example, someone in the forums today said the Volt cells are rated for 5000 cycles (no idea if this is true). The ratings and testing are done for full cycles. Partial cycles don’t count as a full cycle, they just count as part of a cycle. Moreover, lithium cells don’t like to be charged to the top or discharged to the bottom. If you can charge them in the middle of the cells’ SOC they can last more cycles than if you added up the partial cycles.

    Applying this to the Volt, assume that you drive the Volt 40 miles a day and that the battery pack has a total capacity of 40 miles. That means in one year you will put 365 cycles on the battery. Now double the pack size. Now you’re only using half the SOC over the course of a day. It will now take two days to run the battery through one charge cycle. Over the course of a year you’re now only putting 187 cycles on the battery. Double the pack size again and over the course of a year you’re only putting 91 cycles on the cells.

    If you made a pack out of cells that didn’t degrade much over time, like the A123 cells, and you put a lot of cells into the pack, like 80 kWh worth, then the pack would probably last more or less forever because you’d be putting so few cycles on the cells.


  65. 65
    DonC

    +3

     

    Vote -1 Vote +1

    DonC
     Says

     

    Aug 2nd, 2013 (10:22 pm)

    Steve-o: We have often said the Volt is over-engineered. This must be just one example of that.

    No doubt there is a little of this but you can’t overlook the chemistry. The A123 cells are probably just more heat tolerant. Keep in mind that A123 claimed they had cells that were impervious to temperature swings.

    Battery chemistry isn’t everything though. Fisker probably went bankrupt because A123 had problems with the battery production. Given that the LG Chem cells have been more or less bulletproof, I’d say GM made the right call.


  66. 66
    xiaowei1

    +2

     

    Vote -1 Vote +1

    xiaowei1
     Says

     

    Aug 3rd, 2013 (1:02 am)

    Dave G,

    that does not make a lot of sense to say “gen 2″ wont be much better. its has to be, its the next generation that builds on the old technology and brings you a completely revamped product. it may very well be that gen 2 is not the massive upgrade, but GM themselves tell us there is 10k coming of the price, expect a purpose built engine, battery tec is expected to change (enhancing life and potentially retaining value). there are many unknown things, but we know its significant enough to say “Gen 2″… I liked Freds response @ post 6 : “That’s why it’s best to lease instead of buy”. Unfortunately, for me its not an option as I am in Australia and will be paying 60k+ for a Volt (no rebates, no discounts). if they knock of 10k from the price in the US, that’s potentially 15k off the price here.

    what ever is said and done, i would still argue people expect “gen 2″ to be more than a marginal improvement (well, the majority of us), and as open minded as I am, it has actually caused me to hold off on my purchase (though the price is also a consideration). I was hoping for 2014 model to be gen 2, and it still might be, but if I now have to wait another year, so be it, as the price is still too high here in OZ.


  67. 67
    Tim Shevlin

    +3

     

    Vote -1 Vote +1

    Tim Shevlin
     Says

     

    Aug 3rd, 2013 (2:06 am)

    Fascinating forum discussion here. You can be sure that every idea offered here has been discussed by G. M. engineers–oh, two years ago. The next 5 years promise to be very exciting. Hope some of the improvements are retro-fittable. I do enjoy driving a current model…..for awhile.


  68. 68
    Eco_Turbo

     

    Vote -1 Vote +1

    Eco_Turbo
     Says

     

    Aug 3rd, 2013 (7:40 am)

    Electric utilities have a special protected status because of the huge investment that was needed in the early days of electricity to build the infrastructure necessary to distribute it to houses and factories. Maybe we should take away this utility status unless they come up with a way to make their $.60/gallon equivalent fuel usable in all cars. This would include better storage (batteries) and delivery (charging stations). A PPGe of $.60/gallon for everybody would bring on a tide that would float all ships to new heights. I’m not sure exactly how electric co-ops work, but I think it is (was) a way for the customers to own their local electric utility for the purpose of distributing the risk of bringing electricity to rural areas, where the cost of distribution was prohibitively high. What electric transportation needs now, sounds very similar to what electric appliances needed and got in the early part of the last century. I’m afraid that what is developing now is a system whereby utilities will be able to charge more for their fuel. Which would be easy given the cost of gasoline now, and few discussions about PPGe.


  69. 69
    haroldC

    +1

     

    Vote -1 Vote +1

    haroldC
     Says

     

    Aug 3rd, 2013 (9:53 am)

    kdawg: I agree, but not an Impala. In fact, not any existing GM cars. It should be a stand-alone, purpose-built EV.

    A Buick Electra………….
    haroldC


  70. 70
    kdawg

    +3

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 3rd, 2013 (10:33 am)

    haroldC: A Buick Electra………….

    Buick-Electra-Concept.jpg


  71. 71
    Eco_Turbo

    +2

     

    Vote -1 Vote +1

    Eco_Turbo
     Says

     

    Aug 3rd, 2013 (10:50 am)

    haroldC,

    kdawg,

    We’ll never get those cars unless somebody comes up with better batteries and infrastructure. Right now there is only one person working on that in a real way, and his name appropriately starts with an E.


  72. 72
    George S. Bower

    +1

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 3rd, 2013 (11:16 am)

    kdawg:

    Excellent Buick electra kdawg,
    now do this to it
    sparkEVcutaway_zps1a1857f3.jpg

    to show a rendering of the engineering guts of it. Put in the 2 spark EV coaxial gearbox and batteries in the floor. A pure EV with 200 mile range and AWD


  73. 73
    Eco_Turbo

     

    Vote -1 Vote +1

    Eco_Turbo
     Says

     

    Aug 3rd, 2013 (1:04 pm)

    George S. Bower: batteries in the floor.

    Anything to do with a car that’s “floored”, must be good. 8-)


  74. 74
    taser54

     

    Vote -1 Vote +1

    taser54
     Says

     

    Aug 3rd, 2013 (1:23 pm)

    Tim Shevlin,

    Tim, that seems like a backhanded compliment.


  75. 75
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 3rd, 2013 (1:58 pm)

    Eco_Turbo: We’ll never get those cars unless somebody comes up with better batteries and infrastructure. Right now there is only one person working on that in a real way, and his name appropriately starts with an E.

    Eestor?

    (i kid… i kid)


  76. 76
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 3rd, 2013 (8:30 pm)

    OT: I’m in Wixom MI right now and just saw a Spark EV driving down the road. How the heck did they get one in Michigan so quick?


  77. 77
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 3rd, 2013 (9:41 pm)

    kdawg:
    OT: I’m in Wixom MI right now and just saw a Spark EV driving down the road. How the heck did they get one in Michigan so quick?

    Good one kdawg
    way to be sarcastic
    Did it have leather seats?


  78. 78
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 3rd, 2013 (9:46 pm)

    Eco_Turbo: Anything to do with a car that’s “floored”, must be good.

    This thread is about over so we can look at “gas head” photos

    I love this custom bike made from a 52 Vincent Black Shadow motor.

    I want one to ride to the post office :)

    TheBalck52Vincent_zps1a70a887.jpg


  79. 79
    Sean

     

    Vote -1 Vote +1

    Sean
     Says

     

    Aug 4th, 2013 (12:41 am)

    No thanks George if I were to ride a Motorcycle I rather drive electric not a gas guzzler like that.


  80. 80
    Eco_Turbo

     

    Vote -1 Vote +1

    Eco_Turbo
     Says

     

    Aug 4th, 2013 (9:35 am)

    George S. Bower,

    If the post office wasn’t too far away, I guess you could carry the mail in your mouth! Nice motor, at first I thought it might be a V4.


  81. 81
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 4th, 2013 (11:03 am)

    George S. Bower: Good one kdawg
    way to be sarcastic
    Did it have leather seats?

    No I’m serious. There was one driving around last night. I wasn’t quick enough to snap a pic.

    They must of had it shipped here from California or Oregon.


  82. 82
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 4th, 2013 (11:49 am)

    kdawg: No I’m serious.There was one driving around last night. I wasn’t quick enough to snap a pic.

    They must of had it shipped here from California or Oregon.

    I stupidly thought Michigan was one of the states where Spark EV will be sold (cuz of Detroit). but looks like I was wrong. Did it have alloy wheels? How did it look?


  83. 83
    no comment

    +1

     

    Vote -1 Vote +1

    no comment
     Says

     

    Aug 4th, 2013 (1:19 pm)

    kdawg:
    Would the Spark’s battery work in the Volt’s application?I thought it was different chemistries for different applications?Thing’s like C-rate change.

    I’m like most Volt owners and want more EV range.Maybe GM should offer the Volt with either 1/2 the Spark EV pack, or a full pack version.So you could buy the 40mile/day Volt or the 80mile/day Volt.This would allow the Volt to compete with the BMW i3 on the AER range.

    as a general rule, you have to be careful in these volt vs spark comparisons because they are different cars. the spark layout would probably not work for the volt because the volt has to accommodate a gas tank, which the spark does not. i suspect the same can be said with respect to those who call for the volt to adopt a “skateboard” battery layout as you see in many BEVs. again, BEV’s don’t have to design around a gas tank.

    secondly, i think that the issue with fast charging was that gm was concerned about the impact on battery life. unlike a tesla or leaf, fast charging is not vital in operating the volt because of the presence of the generator. in many regards, the volt was designed to be a practical EV for the masses and less specifically for early adopters who are more interested in the technology and are more likely to own the car as a “special purpose” car (i.e. local commuting, &c.).

    i too would like more EV range, like 100 miles, but as a practical matter, for day to day driving, and with a 120 outlet, the 40 miles for the volt is pretty much all that you can get in an overnight charge. since the volt has a generator, gm is able to keep manufacturing cost down by not providing more battery capacity than is needed for day to day driving.

    the bmw i3 is basically a BEV; from what i understand, even if you got the range extender option, you would probably not want to drive in extended range mode any more than you would have to do so. by contrast, when the volt enters range extended mode, the drive characteristics are basically unchanged (other than for the sound and vibration of the generator).

    the volt was designed to be a practical car and not to be a “dream” or “concept” car. by contrast, the tesla, nissan leaf and bmw i3 are niche cars by design. the market segment of early adopters that is most likely to buy an EV, at the present time, is looking for a niche car, so EV range is the most important attribute. for long term viability, EVs have to get beyond the niche – and “fast charging” is probably not going to be what gets EVs out of the niche. i think that elon musk realizes that because he came up with the “battery swap” idea, which is even less scalable than the supercharge station idea.


  84. 84
    no comment

     

    Vote -1 Vote +1

    no comment
     Says

     

    Aug 4th, 2013 (1:24 pm)

    Loboc:

    I’m at 60-80miles per day a lot. I burn gas almost every day in my Volt. Heck, just sell me 50% more battery!

    unless you have a dedicated 240v EVSE in your garage, you are not going to be able to recharge 80 miles in an overnight charge. if you have a 120v outlet, even if you had more battery charge capacity, you would be in the same situation: you would recharge 40miles in an overnight charge (which in this case would be a half charge) and you would end up switching to the generator after you would have used up your 40 miles of overnight charge.


  85. 85
    no comment

     

    Vote -1 Vote +1

    no comment
     Says

     

    Aug 4th, 2013 (1:33 pm)

    George S. Bower: I’d really like to see GM build a 200 mile range Tesla fighter.

    this is where i think that gm is making a mistake with the elr. i don’t think that the 30 mile EV range is going to cut it in a car that is targeted for the luxury segment. this is a car where you really do want to take more of a “cost no object” approach and deliver a car with an EV range of 100 to 150 miles with range extender. then you would have a car in which you would drive EV for the vast majority of local driving with a range extender for extended driving. this is something that you would not be able to do in a tesla. in that case, you would also want fast charge capability. here, it is my sense is that gm might have gone a bit too conservative when it came to the elr.


  86. 86
    Steve-o

     

    Vote -1 Vote +1

    Steve-o
     Says

     

    Aug 4th, 2013 (2:37 pm)

    no comment: unless you have a dedicated 240v EVSE in your garage, you are not going to be able to recharge 80 miles in an overnight charge.

    It isn’t so cut and dried. If you are only home 10 hours every day, that’s all the charge you can get at 12A, which most people can probably manage. However, many people that work 8 hours a day are home more than 12 hours most days, so they could get more than 40 miles per day. If you take long trips occasionally, you can catch up to a full charge after a few days, even if you can’t get a full charge in one day.

    There are lots of scenarios that make this moot, though, like opportunities to charge away from home, or installing a 240V charger. I can’t say a battery that would last more than 40 miles would be useless for very many people.


  87. 87
    Eco_Turbo

     

    Vote -1 Vote +1

    Eco_Turbo
     Says

     

    Aug 4th, 2013 (5:17 pm)

    George S. Bower: I’d really like to see GM build a 200 mile range Tesla fighter.

    From what I’ve heard and read, if GM doesn’t, Tesla probably will. IOW, a less costly version.


  88. 88
    George S. Bower

     

    Vote -1 Vote +1

    George S. Bower
     Says

     

    Aug 4th, 2013 (7:24 pm)

    Eco_Turbo:
    George S. Bower,

    If the post office wasn’t too far away, I guess you could carry the mail in your mouth!

    Good one Eco.
    That’s about the truth.


  89. 89
    kdawg

     

    Vote -1 Vote +1

    kdawg
     Says

     

    Aug 4th, 2013 (11:30 pm)

    George S. Bower: How did it look?

    Pretty sharp. I actually like the solid Voltec grills (i know others don’t), but they are an easy way to say “Hey, I’m different”.


  90. 90
    stuart22

     

    Vote -1 Vote +1

    stuart22
     Says

     

    Aug 5th, 2013 (12:21 am)

    When plugging a Spark in to recharge, is the battery charged to 100% SOC each time, or does it stop somewhere below, such as 80%?


  91. 91
    how to increase youtube views

     

    Vote -1 Vote +1

    how to increase youtube views
     Says

     

    Aug 8th, 2013 (8:53 pm)

    Its like you read my mind! You seem to know a lot about this, like you
    wrote the book in it or something. I think that you could do with a few pics to drive the message home a little bit,
    but instead of that, this is excellent blog. A great read.
    I will definitely be back.


  92. 92
    pjwood

     

    Vote -1 Vote +1

    pjwood
     Says

     

    Aug 20th, 2013 (10:40 am)

    George S. Bower,

    So now that we have the post showing the “.004″ inch plastic tolerance that exists between every other Volt cell, it amplifies the point you were making in post #12. The Volt battery is over-engineered, likely to a cost detriment. I remembered that original article, too, as .004″ is a common air-cooled valve clearance spec. Add what may be >100 feet of coolant webbing, concern for leaks and age, and the production cost begins to quack like a duck.

    They SHOULD do the Impala EREV, because efficiency is the only thing missing from its top Consumer’s score. Buyers don’t need a whole new car. They need to try that model “over there, the one that’s ~4k more than the hybrid”, with more torque, without the weak buzzy on/off, that can save an additional $1,000+ every year. The Big Mac that offers quiet luxury, in a bow tie.

    Like the new Corvette’s modes, I’d even accept a PHEV assist mode, where the engine fires in ‘Sport’, anticipating a 7.0 second 0-60, that the user can otherwise leave at a Volt-like 9.5, in all-electric. Just give ME control of the engine. Chevrolet is showing us, with the Corvette, how far the modal efficiency envelope can be pushed. Let’s get going, guys!

    Car & Driver used to publish interior decibels, oddly when new buyers were younger. GM could lead in a class where I bet they find this criteria still matters. An EV makes a natural premium vehicle. IMO, its the anti-regulatory mind-set of the board rooms and many journalists, that is leading to this great “Miss”.

    Great piece, George. Thanks for the link back, on 8/20.