Design Article
It's the battery, stupid
Christoph Hammerschmidt
11/18/2009 8:27 AM EST
But not only cold days take their toll. On hot summer days, it was the equipment such as pumps and fans necessary to keep electronics and batteries at their operational temperature that consumed extra power, again reducing the driving range.
And while in a normal car with combustion engine the tank can be filled in minutes, owners of e-cars have to be much more patient. The charging process takes as much time as a transatlantic flight, the tester of an Audi R8 e-tron noted. To charge a BMW e-Mini took some 12 hours when connected to a standard power outlet; when a three-phase power outlet was used, charging time was reduced to five hours — still much too long for everyday use.
To complete the negative picture, the energy costs for the electric sets of wheels appear not to be as low as e-car prophets have predicted. For the e-Mini, the electric power consumed burdened the driver's budget not less than a diesel car. While this calculation has been done on the basis of the high fuel prices in Germany, and in other countries the result may look somewhat friendlier, it shows that e-cars are not the economic sister of conventional cars (even if one does not take in account their high price).
So is e-car a dead-end street? Are critics such as Aston-Martin boss Ulrich Bez right who recently dismissed the e-car discussion as insubstantial hype? Wouldn't it make sense to focus R&D budgets on improving the efficiency of conventional drives? After all, there has been remarkable progress in the past years and engineers in tier ones promise to bring down fuel consumption by another 30 percent, so wouldn't it make sense to go this direction?
I don't think so. Indeed, it's the batteries that currently are the weakest part in the e-car concept. However, this is not a new insight; all battery manufacturers and e-car OEMs don't get tired of emphasizing this point. We should not forget that e-cars and the related technology are still in their infancy. It will take a decade or more to bring them to a performance level comparable to what we see in today's conventional cars. This takes a lot of stamina.
Hey, this is like the moon landing project: In the beginning, the goal was so high that many doubted it ever could be achieved. We now know that it paid out not to give up. The same wisdom holds true for alternative drive technologies and concepts — despite these disappointments.
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fastniky
11/24/2009 12:33 PM EST
Ever hear of Proterra? Look up proterraonline.com
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Roger P.
11/24/2009 2:35 PM EST
It is about time that the matter of the exagerrated ranges of electric vehicles is being addressed. The true ranges are far less than stated. Battery service lives and replacement costs also need to be addressed. First-generation electric vehicles will be a disappointment to their owners and have poor resale values once the second generation hits the market. I am not looking forward to the day when our roads are blocked by stalled electric vehicles whose operators believed in their stated ranges. Electric vehicles should be banned from high-speed motorways until such time as they can demonstrate ranges of at least 100 km at sustained, typical, motorway speeds, i.e., 100 km/h to 130 km/h.
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Bobmoto4
11/24/2009 4:46 PM EST
Talking about charge time, everyone sleeps for longer than it takes to charge a vehicle. The only issue is range for a given day. The EV is perfect for 95% of drivers that commute to work daily. You have a full charge each day, and taken off-peak when rates are low. With complementary grid-tied solar on your home's roof, the grid will get free load leveling, which helps the power companies, and can net-zero your energy cost for daily driving.
So Roger, have you not heard of the Tesla that actually makes 390kM per charge, and, is faster than most ICE vehicles? Take it from someone that drives electric, you will not randomly be stuck on the road! It is no more likley than driving a gas vehicle, considering there is a guage to look at for remaining range. Your comment about banning a vehicle type based on your mis-perception is a clear sign that you have not been following the technology very closely.
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Tony41
11/24/2009 5:32 PM EST
I am an engineer and I drive a Prius with 150k miles on it. The battery has not been a problem in this type of use. I expect it to last to 300k.
However, I have problems with all of the claims coming from all of the car companies about battery use. The all electric car would be the best thing to hit the car industry, but batteries will not work as the only power source. A battery will never be able to supply the kind of power needed for these applications. I have done the math no electrical storage device can run a car the way I use it. You will always need a separate generator producing power using gas, hydrogen, natural gas, solar nuclear...etc.
Even with the perfect battery (not yet invented) you will never be able make this work with only a battery as the power source. Come on guys, you must have a few smart people that have told you this.
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RDWRIOR
11/24/2009 9:51 PM EST
I work for GM. Reading this blog and the comments reminded me of a discussion I had more than a decade ago with one of my former colleagues. Earlier that day we had been given a presentation by another colleague regarding the EV1 electric vehicle program. (This was about one year after that vehicle was made available for lease to the public in CA and AZ, and years before the program was terminated. The impression then was that the program would be sustained for the foreseeable future.)
One of the topics presented was future battery technology that would extend the EV1 vehicle's (relatively low) range. When I discussed this later with my colleague, I expressed skepticism that future battery technologies would ever deliver "breakthrough" performance. It seemed that EV proponents really believed that it was just a matter of time (and research money) before a "perfect" battery would be developed. My thinking then -- and now -- is that such a breakthrough is extremely unlikely in the near future, and may never be found. The desired characteristics (low mass, high power density, fast recharge time, etc.) have been important for decades. Certainly there have been "cost is no object" military and space programs that would have been the catalyst for such battery development. So, where are the "super" batteries?! (BTW - My colleague, who was a "veteran" of the '60s aerospace industry in CA, agreed with my rationale and shared my skepticism.)
Just about every popular, mid-size gasoline/diesel engine vehicle sold today in the US can achieve at least 300 miles of unrefueled range in highway use, and can be refueled from empty in 10 minutes or less. Does anyone think that a "pure" battery EV will EVER offer the same performance? Maybe in 10-15 years evolving battery technology will be able to offer the same "unrefueled" range in a vehicle of similar size/mass, but a 10 minute recharge? Not likely, if ever, in my opinion. This is why I expect EVs will never be more than a small segment of the personal vehicle market -- they do not (and likely never will) offer the freedom of driving range that gasoline/diesel engines can offer. EVs will be acceptable for some people, mostly urban dwellers, with short distance driving needs. But even some of those potential urban customers will probably be dissuaded by the knowledge that their one-day driving range (i.e., before an overnight recharge) is as limited as a traditional vehicle is to just one tank of fuel. Also, some of those who actually do adopt EVs are eventually going to forget to recharge the vehicle. For them, we can expect these sorts of exchanges with their employers:
Boss: "Why didn't you make it to work on time this morning?"
EV-owning employee: "I forgot to recharge my car's battery last night!"
I'm all for continued battery development, but there seems to be a notion that some sort of "perfect" battery will be developed if just enough time and money are devoted to the project. I'm highly skeptical of that. Development resources are always finite. Devoting a large share of those finite resources to battery EVs -- based on the notion that this type of vehicle is the one best solution for future personal transportation needs -- is silly, in my opinion.
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Bobmoto4
11/25/2009 10:38 PM EST
I didn't mention on my earlier post that the charge time CAN be less than 15 minutes, regardless of the pack size. Before you laugh at this notion, consider this: with a bank of batteries in a room (at a charging station), massive currents can be delivered to a vehicle over some fat cables. This would require a "stiff" grid connection to achieve the same results, i.e. less practical.
When vehicle packs are considered end of life, there is still 70-80% capacity in them and will be turned into battery banks for fast charging. The power companies already do this with lead acid to back up the grid, and we are talking massive currents.
The cells that are now in production (and which I am using in my high performance conversion), can charge to 80% in 15 minutes, and are the first generation LiIon iron phosphate (A123 cells).
To address Tony41's statement that there couldn't be a battery that supplies the kind of power he demands. This is NOT the case at anymore. I have a pack than can deliver much more HP than you will ever have in your vehicle. Power density is such that I can deliver 930 HP in my BMW electric. I don't have a motor that can draw this yet.
But I have been demonstrating this power density on my electric motocross bike with a significantly smaller pack. The only issue is range, at that has already doubled in the last 2 years.
IBM is hard at work on a new chemistry that they have recently stated with confidence the expectation of at least 10X the energy density over Li Ion cells. Right now, all around the planet, there is massive development efforts going on to develop a better cell, now that there is such desire for electric transportation, which was not the case in past years.
Full performance EV's are far from silly.
check out this site: evdrive.com
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henkmol
12/1/2009 3:56 AM EST
Hi, I work as a mechatronics research and development engineer for a tier 2 mechanical components maker in industry and automotive. I have a lot of questions about e-vehicles and I have problems to make the technical and business ends meet. Q1: what is the cost today of a kWh of LiFePO4 battery and why. Reading the conclusions of Lux Research, the Li battery cost per kWh is now 200 times as high as the lithium feedstock cost per kg (4.6 euro/kg for Li2CO3) Can anyone confirm or revise the numbers. Q2: what is the forseeable cost in 4 years from now per kWh. If it does not sink below a some 250 euro/kWh then it cannot become a mass market unit. Q3: who can recycle worn Li batteries and how is it done, what is the energy balance in this recycling. Q4: What impact with the "smart grid" have on your charging needs. After all, if the grid is faced with hundreds of thousands of cars to be charged, the demand jump cannot be handled, especially in the summer season where some 30% of a grid's power in the afternoon and evening dissapears into fixed installed airco's. Really, in the summertime electricity consumption generally far surpasses wintertime consumption. Adding a few percent of e-cars to a national fleet will simply crash the net - this will therefore not happen. Will a car owner accept that the electricity network manager controls when and how much he can charge? Will a car owner also accept a substantial investment into a local energy storage, say a 1m3 10kWh super capacitor to fast charge his car, in his basement? Q5: What is the preferred electrical motor in a road vehicle, DC Brushless or AC induction, and what size and weight per kW peak power do such motors need. If needed in large volumes, DC brushless (say 75 kW rated) motor manufacturing will run into lack of critical heavy rare earth metal (dysprosium) needed in the magnets to operate them under automotive temperatures.
Thanks, regards and keep up the debate, Henk Mol.
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jack1234
12/2/2009 4:42 PM EST
Gentlemen, i am a power electronics design engineer who worked on EV's.
Why all the hub-ub about the pure EV? there are enough hybrid cars on the road to end this string of "clever" remarks that the EV is doomed to failure. Who says we ever have to find the "prefect" battery? It may never happen and so what? The Honda and Toyota hybrids are fine already with enough range and enough cost savings on fuel.
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