OBSESSIVE COMPULSIVE DISORDER AND A123 BATTERY CELLS

What do you mean obsessive/compulsive?

This week we continue our obsession on A123 cells. I fear this obsession on developing a mechanical package for these cells to use in a car is going to cost me my entire viewership of our EVTV weekly show.

But we continue to pursue it for a number of reasons.

FIRST. We think this higher power cell opens the door to a different kind of power pack for electric vehicles. Not dramatically different, but just conceptually different. Our DIY crowd lives in a strange space of time, space, and money restrictions that VW and BMW simply do not face.

As a result, EVTV has lived in a strange grey zone of tension between those who want to build excellent electric vehicles and those who want to do it inexpensively. There is a little army of guys out there still building lead acid vehicles because they perceive the $3000 of lead cost as workable and $10,000 for Lithium as not. They desperately want to be perceived as "pioneers" in the electric vehicle movement. When I tell them they are not only NOT pioneers, but actually damaging to the cause, it drives them into a frenzy of hostility and abuse mostly directed at the messenger ME.

Let me repeat: lead is dead. IT is at this point a NOT very interesting science project. It is not a car. ANd it reenforces false stereotypes about electric cars among the public. If you have a lead powered electric car, please hide it from view.

But the desire for a lesser cost battery, and the willingness to settle for less range, just might be an itch we can scratch with the A123 MD1HD-A 20Ah pouch cell.

Here's why. This cell only has 20Ah of energy in it and in testing, really more like 19 Ah. But it can put out 20C of POWER and so it's POWER density is quite high. To drive a 1000Amp controller and motor, would only require three of these cells in parallel. A 60Ah pack would cover up to 1350 amps actually which encompasses the power requirements of every single vehicle we've done at EVTV including the eCobra.

And so a 100 Ah pack is actually overkill for a normal car with regards to power or instantaneous current requirements. But it is a smaller pack than we normally use.

As an exercise, let's redesign our pack for Speedster Part Duh. This vehicle is limited to 120v by the controller. If we did a 100Ah version of this at 5 cells in parallel, we would actually be a little less than that, probably 90-95Ah. At let's say at 120v, such a pack would of course have 10,800 kWh. But the weight of the cells, not counting any modules, would be more like 180 lbs instead of our current 450 lbs and could conceivably bring our wH per mile down to 200. That's a 54 mile range to 100% DOD and of course 43.2 miles to 80%.

The national average for a daily drive is 39.4 miles and 78% of the population can deal with a car that does 40 miles or less.

The car would be lighter. And the cost of the cells based on our last purchase would be $4770. The cost of the cells we HAVE in it now for an 80 mile safe range is a bit over $8000 with shipping.

And so we have lead acid, with 1200 lbs of cells and about a 30 mile range at $3000, the CALB 180's with an 80 mile range at 450 lbs of cells at $8000, and the A123 at 180 lbs and 43 mile range at $4800.

The A123 fills in nicely and the CAR actually PERFORMS better than either of the other options because of lower cell weight and so lower vehicle weight.



But perhaps most importantly, the initial cost is closer to the lead $3000 cost than it is to the CALB 180's $8000 cost. And the car is not only fully functional, but probably super functional as it will drive better at a light weight than it will with the CALB 180 cells.

IF you then like the car, and need more range, ADDING cells to the system is almost a trivial exercise.




And so we see these cells as allowing a whole new group of our viewers who mostly view, finally get started to build. That's a big play for us and a big play toward the adoption of electric drive for personal mobility worldwide.

REASON TWO. I'm just incensed at the hubris of Miet Ming Chang and the A123 group in accepting $249 million dollars and publicly dissing ANYONE not an OEM qualified in their mind to be an OEM right on their web site WITH my tax dollars in their jeans. I'm further incensed that they would lay off 125 hapless yucks the first time Fisker hits a glitch, saving themselves what $7 million a year in payroll while lunching at the Fish on their $249 million dollar grant.

I'm THEN incensed that they actually make the cells in Korea, and have MADE IN USA printed on them there.

And then I'm enormously entertained that FISKER has now missed the milestones on THEIR Department of Energy LOANS and have shut down their production and layed off 65 workers. This is a company A123 invested $30 million dollars in, and lo Fisker announced A123's cells to be the very highest quality available.

Now A123 has a rather diminished need for cells.

And so it APPEARS that the Asian factories, facing plummeting demand from A123, are actually selling the cells out the back door to Chinese traders. And there we purchase them.

Several people have alluded to the fact that these may be "reject" cells from QA or "seconds" or otherwise undesirable cells. I would note that EVERY person I have heard this from also sells competing batteries. It is just dehumanizing to watch the "who's ox got gored" scenario play out EVERY TIME in EXACTLY the same way.

Our examination and testing would tend to indicate that the cells we are receiving are brand new and of acceptable quality per the published specification. At some price, the performance is what the performance is and we find 18.5 to 19.5 Ah of energy density and a full 23C tested current capacity very persuasive at these prices.

So reason two is simply that it tickles my fancy to buy cells from China purportedly made in the USA from a US manufacturer who's head is so far rammed up their own ass you would have to e-mail them JPEGS of sunlight if you ever want them to know what it looks like.

REASON THREE has to do with establishing the ongoing market price of these cells. The factory and traders have to make some level of profit to continue making the cells at all. I don't know where the floor is. Our first purchase was a little over 2 months ago at $36 per cell I think. Our latest purchase in December was at $20 per cell plus shipping and paypal charges. Nathan Knoppenberg reported this week a quote of $17.40 FOB china. I asked my guy and he quoted $19.20. As these two quotes were from the same company and our viewers have already purchased several thousand cells from this guy, I kind of went ballistic on him. His response is that I can have them at whatever price I want to pay.

Lower pricing is good. You want to squeeze. But when you squeeze all the oxygen out of the room, understand that the supply might just disappear.. In infant industries such as this, while you are seeking the lowest price, understand that it is generally in your interest for these people who make motors, controllers, batteries, et al to remain in business and for it to actually be an attractive business for others as well.

In any event, CALB cells are at $1.20 per amp hour and TS/Winston/Sinopoly somewhere around $1 to $1.05. At anything like $19 and below, these A123 cells suddenly make sense in a lot of ways. At $15 they pretty much kill off the larger prismatics.

REASON FOUR - it may just be a better battery. A little over a year ago, in our December 6, 2010 blog entry "What heSaid, What I said" a professor Jay Whitacre of Carnegie Mellon University did a video addressing the Carnegie Mellon EV club and talking about batteries, battery management systems, chemistry, etc. This guy has had quite a career specifically with Lithium batteries going back to the NASA/Jet Propulsion Lab and a decade of it. In this video, he several times held up the A123 cell as the "gold standard" by which LiFePo4 cells should be compared. Since then, A123 has done several presentations to DOE as to how they have improved their cells, and mostly this 20 Ah cell. It is a LONG way from the little can cells used in the deWalt power tools.
(Incidentially deWalt as it turns out has a patent on a little BOTTOM BALANCING battery charger).

Now Daniel A Cogswell and Martin Z. Bazant of MIT have published a paper, Coherency strain and the kinetics of phase separation in LiFePO4 that would appear to imply that fracturing of the crystalline matrix in LiFePo4 cells may be DIMINISHED by the use of HIGHER current levels during charge and discharge. In other words, the harder you work em, the longer they last. I have for about a year now thought that the disconnect in the broad electric vehicle community that I feel is about really smart people NOT looking hard enough at these LiFePo4 cells because of their lowish energy density. They don't REALLY know why these cells work, and yet they are moving on to others that have none of the same advantages, for a few ma of energy. How about driving THIS chemistry to its limits first.

Our latest module uses a mold we made from a CALB 180 prismatic cell using Mold Star 30 Platinum Silicone Rubber from a company titled SMOOTH-ON. This took about 16 hours to cure but gives me a very durable but flexible rubber mold to pour cast urethane in. The material needs no release agent when used with urethanes. So you just pour it in and in 10 minutes pull it out.

The urethan resin we used this week (resin du jour as we try a lot of different ones) is their SMOOTH CAST ONYX which has a deep glossy black finish. It takes about 40 ounces in our mold. The bad news there is there is this stuff is $94 per gallon meaning we could do three batteries per gallon or EACH cell would take about $31 plus shipping just of resin. We probably need to find something less expensive.

Assuming about $10 worth of hardware, $31 in resin, and six cells at $26.50 our little battery costs about $200 each for 115 Ah. And our 36 cells in Speedster Duh, instead of the theoretical $4800, is more like $7200. Of course, that is with 120 Ah instead of the 100Ah described at the beginning. But you can see that the form and the cost of the actual modularization of these pouch cells is what it is entirely about. You can wipe out the advantage of them if you have too high a costs in the module. And of course you wipe out the advantage if the modules can't handle the current or lead to early cell death.

So we are doing more work on a module. But we had kind of hoped our viewers would do some work in this area as well.

We also took a first look at Valery Mitzikhov's EMW Bluetooth Dashboard for Android in this episode. MORE ON THAT LATER. This is a fascinating device with a few early version problems.

Yes, the audio is wretched in the first part of the show. Brain forgot to change batteries in the Juiced Link. We would not have even HAD a show but for our new backup TASCAM DR-100 recorder. But even there, he had the microphone pointed at the wall instead of at us and so the sound is like being in a bathroom. We'll do better. I hope....



Jack