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I'm a little skeptical about the lithium batteries.

Toyota is slow to offer a PHEV.

NiMH batteries have longer life and reliability at this time.

My gut feeling is GM never should have sold the EV1 battery copyrights to Chevron - should have expanded on it for the Volt.

My gut feeling is lithium problems will somehow kill the Volt.

Of course it may be others are smarter with lithium than GM.

I would love to get my hands on a NiMH powered EV -- there are actually two Ford Ranger EVs fitting this description currently up on eBay.

However, I do think there is reasonable hope that lithium can be made to work quite well. Nissan's record with lithium powered EVs is pretty decent and I look forward to seeing their Leaf on the road.

It seems Ford is going with a Manganese Spinal chemistry, and I've seen at least one reference indicating that those batteries may have the same thermal runaway issues that LiCo chemistries do... that would put me off of the Ford implementation. Perhaps I'm wrong, though?

Either way, I watch this field with great interest!

Now... will I be able to get a 300mi AER vehicle powered by an EESU sometime in 2012? ;)

If I remember correctly Ricardo from A123 said at Green Drive Expo that the A123 batteries have been tested for over 9000 charge discharge cycles and still hold over 80% change. If you charge 1 time a day that's about 24 years or about 12 years if you charge 2 time a day. As long as the battery chemistry holds up over that many years these batteries will be fine. I dont have any worries about them.

I put some faith in Li-Ion batteries based on a few high-quality devices that have far outlived my expectations. For example I have a Norelco electric shaver that I bought in 2003 with a lithium polymer cell. Yes, it's a light-duty application. But I'm absolutely floored by the fact that it runs for months of daily use on a single charge after 6 and a half years. Age alone should have killed it off by now.

I also have a ThinkPad for work that has a special battery management utility so that I can set charge thresholds. I hold it to 30% min / 85% max (unless I need it for a trip or something) and its measured capacity is still 100% of its rated capacity after nearly two years. So it's not just about the better cells, but having the knowledge to use them intelligently.

I put some faith in Li-Ion batteries based on a few high-quality devices that have far outlived my expectations. For example I have a Norelco electric shaver that I bought in 2003 with a lithium polymer cell. Yes, it's a light-duty application. But I'm absolutely floored by the fact that it runs for months of daily use on a single charge after 6 and a half years. Age alone should have killed it off by now.

I also have a ThinkPad for work that has a special battery management utility so that I can set charge thresholds. I hold it to 30% min / 85% max (unless I need it for a trip or something) and its measured capacity is still 100% of its rated capacity after nearly two years. So it's not just about the better cells, but having the knowledge to use them intelligently.

The lifetime effects of different charge/discharge and temperature profiles is very significant. Your parameters (30/85) should keep you well above the knee in the lifetime curve. According to my understanding, the real knees in the curve are at 20/90. However, accurately measuring actual SOC on a single Li-Ion cell with consumer grade instrumentation is not a trivial task. Doing the same prediction on a module level is much more difficult. Setting your limits at 30/85 is a very wise decision and likely the primary reason why your Thinkpad battery has such a remarkable endurance. Unfortunately, this is an expensive option for automotive companies. The battery pack is composed of dozens of modules. They have 3 choices:
1. Do as Brick has done - set the limits very conservatively and pay the cost of not using the full capacity.
2. Extensively characterize the battery and develop software algorithms that accurately predict the battery SOC under all customer usage scenarios. This requires an enormous investment of time and money before production commences.
3. Hope that battery lifetime is well correlated with cell manufacturer predictions.

I am not much of a gambler - I only see 2 realistic choices.

I would love to get my hands on a NiMH powered EV -- there are actually two Ford Ranger EVs fitting this description currently up on eBay.

However, I do think there is reasonable hope that lithium can be made to work quite well. Nissan's record with lithium powered EVs is pretty decent and I look forward to seeing their Leaf on the road.

It seems Ford is going with a Manganese Spinal chemistry, and I've seen at least one reference indicating that those batteries may have the same thermal runaway issues that LiCo chemistries do... that would put me off of the Ford implementation. Perhaps I'm wrong, though?

Either way, I watch this field with great interest!

Now... will I be able to get a 300mi AER vehicle powered by an EESU sometime in 2012? ;)

I do not think that there is a single battery chemistry in the world that cannot be forced into a thermal runaway condition under the wrong treatment. I have seen the results when a 6 volt lead acid battery was abused (the air force never investigate whether it was a charging or shorting issue). The battery put a dome shaped bulge in 1/2 thick steel plate.

The key is to avoid the conditions that will cause thermal runaway. The test data I have seen indicates that lithium manganese oxide chemistries definitely require significant controls to manage this. As a general rule, the higher the energy density of the battery, the tighter the controls must be in order to manage thermal conditions.

Chuck, I think the answer to your question is "YES" - at least for now. I'm all for:

Condemning the NiMH patent under eminent domain.
Immediately placing NiMH technology into the public domain, and
Compensating the owner for a prorated share of its original investment, plus lost royalty revenue based on the current rate of sales. This might only be a few billion at most, considering they seem not to be licensing out very many large format cells at the moment. The benefit to society of doing this would outweigh the cost many, many times over.


I think the above compensation is generous. Thomas Jefferson opposed granting patents, period, for exactly the monopolistic reasons we see in play today. Catch me in a different mood, and I'll probably tell you we should give Cobasys NOTHING in return for what they have done.

I do think Li will eventually become the preferred choice, but it's probably at least a couple years off. Besides open questions about battery lifespan, my understanding is NiMH still has a cost advantage. Maybe not for long as Li costs continue to drop, but I don't think we're there yet.

That-selling the rights to Chevron- is one of the downsides of capitalism.Capitalism, and the free market in general-don't have any "national interest."
Bright folks developed GMs battery technology, but it was sold off to folks who intentionally buried it.

The free market isn't always good for the USA- energy policy is a good indication of that.We the USA- can be held hostage by any of several unfriendly countries-Ven,SA,Iraq,Iran..If any of those countries decides just just quit producing we would be screwed until we developed alternatives, and undertook extreme conservation.

Sorry to be veering wide.
I would be fine with the older technology. I had a lithium battery flashlight blow up on me once-nasty little bluish explosion and fire-acrid smoke etc
Charlie

The lifetime effects of different charge/discharge and temperature profiles is very significant. Your parameters (30/85) should keep you well above the knee in the lifetime curve. According to my understanding, the real knees in the curve are at 20/90. However, accurately measuring actual SOC on a single Li-Ion cell with consumer grade instrumentation is not a trivial task. Doing the same prediction on a module level is much more difficult. Setting your limits at 30/85 is a very wise decision and likely the primary reason why your Thinkpad battery has such a remarkable endurance. Unfortunately, this is an expensive option for automotive companies. The battery pack is composed of dozens of modules. They have 3 choices:
1. Do as Brick has done - set the limits very conservatively and pay the cost of not using the full capacity.
2. Extensively characterize the battery and develop software algorithms that accurately predict the battery SOC under all customer usage scenarios. This requires an enormous investment of time and money before production commences.
3. Hope that battery lifetime is well correlated with cell manufacturer predictions.

I am not much of a gambler - I only see 2 realistic choices.
Here's an easier solution - allow the driver to select the maximum charge level. It can default to 85%, but allow up to 100% if the driver chooses to do so for a long trip. There really isn't any real need for a soft low limit as it would not normally discharge that low.

Personally I would never trust the average consumer to make a decision like that. Those of us who understand the tradeoffs and the ramifications will tend to make good choices and get long lives out of the packs. Appliance drivers don't think abou these things. "Well, I paid for a big battery why can't I use the whole thing?!?" Dead battery in less than two years and a consumer who doesn't understand why. This is one of those things...expensive and new with plenty of market risk...that really does need to be child-proofed.

Personally I would never trust the average consumer to make a decision like that. Those of us who understand the tradeoffs and the ramifications will tend to make good choices and get long lives out of the packs. Appliance drivers don't think abou these things. "Well, I paid for a big battery why can't I use the whole thing?!?" Dead battery in less than two years and a consumer who doesn't understand why. This is one of those things...expensive and new with plenty of market risk...that really does need to be child-proofed.
Call it "long trip mode" and explain to the customer that misusing it for short trips will void the warranty.

I think you'd still have issues with the people who drive long distances every day.

Or, even more likely, those who are like my wife and let their devices all but die before plugging them in. The best way to use an EV is to plug it in every night. Most people probably will try to go as many days on a charge as they can instead. :(

Every expensive bit of consumer technology needs to be idiot proofed.If it isn't someone will cook their battery in short order and the manufacturer will get bad publicity.

Better idiot proof the battery tech software. If more adept consumers want to run closer to the edge, they'll be able to buy some sort of bypass program to allow that.
Many Prius II owners have the EV buttons that the Euros get .I'm not sure why-we in the USA- are denied the EV button ,since we apparently already have software that will protect the battery pack from being drained too low.This isn't a great example since it is more or less a OEM option not an aftermarket hack.

Charlie

Every expensive bit of consumer technology needs to be idiot proofed.If it isn't someone will cook their battery in short order and the manufacturer will get bad publicity.

Better idiot proof the battery tech software. If more adept consumers want to run closer to the edge, they'll be able to buy some sort of bypass program to allow that.
Many Prius II owners have the EV buttons that the Euros get .I'm not sure why-we in the USA- are denied the EV button ,since we apparently already have software that will protect the battery pack from being drained too low.This isn't a great example since it is more or less a OEM option not an aftermarket hack.

Charlie

Agreed.

In this case, Charlie's point is even more important than normal hi-tech precautions. Cooking a Li-Ion battery is not a trivial issue ...