Thought experiment - A Leaf with Lead Acid Batteries

[DaveinOlyWA]

Id rather see all 3

What would a LEAF wi th a 16 kwh battery cost?

It would cost almost exactly the same as this car.
http://autos.yahoo.com/mitsubishi/i-miev/2012/" onclick="window.open(this.href);return false;

The biggest complaint with the Leaf is lack of range. This would just make those complaints louder.

I would much rather see a Leaf with a 36kwh battery instead of a 16 or even a 24 like it has now.

kjd

 

[JeremyW]

I think it might be interesting to add a NiMH LEAF to the experiment. Particularly regarding battery degradation. I keep reading of RAV4-EV owners who claim that their packs are still like new!

Starting with this we see that the RAV4-EV (first gen) has a ~27kWh battery pack, weighing in at 461kg (1,016 lb). Scaling it down to what the leaf comes with: 24kWh, 410 kg (904 lb). Compare that to 300 kg (660lb) of the leaf battery. Not bad.

Now, lets look at occupied volume. I found the data sheet for the NiMH module here. The volume of one module is 7.87L, and one module is roughly 1.14kWh giving 6.90 L/kWh. The leaf cells are a bit thin on the volume dimensions. The closest I could find was the AESC website here... 0.1229L and 0.014kWh for an example cell using the same chemistry giving ~8.77L/kWh

Huh. Wasn't expecting that. I'll let others do more research, but even the AESC website shows overlap on their "technology graph" between NiMH and Li-Ion as far as volumetric energy density is concerned, so the numbers are at least plausible.

I'd also like to note that going with Lithium means your cell voltages are much higher. This has advantages in inverter and wiring design considerations, as well as lower amperage through the cells means less (I squared R) loss and less heat.

I seem to recall that the Cobasys patents for the Ovonics NiMH will expire not to far in the future. Might we see a return to NiMH for mass-market EVs?

Maybe, if they can be made cheaper than Li-Ion. I'd watch Toyota, as they are the NiMH experts. If anyone is going to, it'll be them.

Jeremy

 

[DaveinOlyWA]

i think we want to stay away from linking hybrid technology to EV technology because they could not be more different.

Toyota's huge technical advantage in hybrids and NiMH will do nothing for them in the EV world. maybe the same battery but the application is simply too different to make any comparisons

 

[adric22]

i think we want to stay away from linking hybrid technology to EV technology because they could not be more different.

I couldn't disagree more. Manufacturing a reliable hybrid means learning how to integrate large scale batteries in a car and keep them cool. It means creating motor controllers and cooling systems for those controllers that are reliable. They must integrate regenerative braking, cell balancing, cell monitoring, electric HVAC systems, electric coolant pumps, backup capacitors for braking systems, etc.. There are just so many technologies that cross over between hybrids and EVs I couldn't begin to name it all.

 

[DaveinOlyWA]

i think we want to stay away from linking hybrid technology to EV technology because they could not be more different.

I couldn't disagree more. Manufacturing a reliable hybrid means learning how to integrate large scale batteries in a car and keep them cool. It means creating motor controllers and cooling systems for those controllers that are reliable. They must integrate regenerative braking, cell balancing, cell monitoring, electric HVAC systems, electric coolant pumps, backup capacitors for braking systems, etc.. There are just so many technologies that cross over between hybrids and EVs I couldn't begin to name it all.

well then, lets add it up. the Prius only uses 40% of battery capacity. so instead of it being a "few hundred" lbs heavier it would be several hundred pounds heavier. we think that just because a Prius can run 400,000 miles without a battery replacement that we could do that in an EV environment? well, that aint gonna happen without some major developmental work.

right now, Prius batteries are suffering premature failure in AZ...now "premature" is relative since they are still going beyond their warranty but i would be pretty upset if my Prius needed a new pack after 175,000 miles when all my northern neighbors are going 250,000 to 400,000

also, Toyota is not stupid. if they had the answers, you seriously think they would have put out the lamest plug in vehicle on the market? trust me. they also know that the foundation built on their hybrid knowledge would not hold up much in the EV world

 

[adric22]

well then, lets add it up. the Prius only uses 40% of battery capacity. so instead of it being a "few hundred" lbs heavier it would be several hundred pounds heavier. we think that just because a Prius can run 400,000 miles without a battery replacement that we could do that in an EV environment? well, that aint gonna happen without some major developmental work.

I didn't say a hybrid was "exactly" like an EV. I just said that there is a lot of cross over technology and knowledge of working with hybrids is a big step towards EVs. You asserted that knowledge of hybrids would be of NO benefit, and I disagreed.

 

[DaveinOlyWA]

well then, lets add it up. the Prius only uses 40% of battery capacity. so instead of it being a "few hundred" lbs heavier it would be several hundred pounds heavier. we think that just because a Prius can run 400,000 miles without a battery replacement that we could do that in an EV environment? well, that aint gonna happen without some major developmental work.

I didn't say a hybrid was "exactly" like an EV. I just said that there is a lot of cross over technology and knowledge of working with hybrids is a big step towards EVs. You asserted that knowledge of hybrids would be of NO benefit, and I disagreed.

ok, no problem, we all have our thoughts and i value yours.

hybrid technology is the marriage of gas engines and electric motors. Toyota excels because, well that is easy. they get 50 mpg and after 8+ years its hard to say the rest of the auto industry is playing catch up but that is basically the case.

EVs have no fall back. its battery or nothing which means completely different drive train, BMS, depth of discharge, HVAC, i mean, its literally a totally different technology. discharging to 5% SOC then charging to 95% SOC is a completely different technology at play.

 

[ztanos]

well then, lets add it up. the Prius only uses 40% of battery capacity. so instead of it being a "few hundred" lbs heavier it would be several hundred pounds heavier. we think that just because a Prius can run 400,000 miles without a battery replacement that we could do that in an EV environment? well, that aint gonna happen without some major developmental work.

I didn't say a hybrid was "exactly" like an EV. I just said that there is a lot of cross over technology and knowledge of working with hybrids is a big step towards EVs. You asserted that knowledge of hybrids would be of NO benefit, and I disagreed.

ok, no problem, we all have our thoughts and i value yours.

hybrid technology is the marriage of gas engines and electric motors. Toyota excels because, well that is easy. they get 50 mpg and after 8+ years its hard to say the rest of the auto industry is playing catch up but that is basically the case.

EVs have no fall back. its battery or nothing which means completely different drive train, BMS, depth of discharge, HVAC, i mean, its literally a totally different technology. discharging to 5% SOC then charging to 95% SOC is a completely different technology at play.

It's a different battery technology. The main drive components are rather similar. Look at the volt which can be considered a hybrid. Take out the gas engine and you have a LEAF with a smaller battery.

 

[ztanos]

i think we want to stay away from linking hybrid technology to EV technology because they could not be more different.

right now, Prius batteries are suffering premature failure in AZ...now "premature" is relative since they are still going beyond their warranty but i would be pretty upset if my Prius needed a new pack after 175,000 miles when all my northern neighbors are going 250,000 to 400,000

To the same token. Do you think that most car owners get mad when their engine only makes it to 500,000 before needing to be rebuilt when they know that others have made it farther?

 

[Herm]

You all may think different, but you dont want to own a 10 year old battery.. you will be sick from envy about all the other options available in 10 years. Batteries will improve, and they will improve a lot.

 

[ztanos]

You all may think different, but you dont want to own a 10 year old battery.. you will be sick from envy about all the other options available in 10 years. Batteries will improve, and they will improve a lot.

I'm also sick with envy from all the other options from my 2001 Saturn SC2 with 155,000 miles. What does that say? Newer technology is better? Duh!