Smart Car EV battery...

[steveo]

Does anyone have any detail/pictures of one?

specifically:

the cells inside?
cells model info?
Specs?
cells in parrallel?
cells in series?
Voltage?
Max discharge/charge rating?

I can't seem to find anyone on the net thats posted info/teardown info ..

thanks
-steveo

 

[wb9k]

No tech details, but as a side note of perhaps some interest, I saw several of these vehicles on the road during a recent trip to Stuttgart. They have some sort of car-loaning program going with these--they are very plainly marked as fleet cars. I was told they are available for use by anyone who wants to participate in the program.

 

[Hillhater]

I believe the Smart EV uses the tesla built 18 kW hr pack. 18650 cells in modules of 330 cells 15 S, 22 P.

Some. Of those used modules are available from EV West
http://www.evwest.com/catalog/product_info.php?cPath=46&products_id=329

 

[circuit]

Yup, it looks like Tesla is making battery packs for other vendors, Smart included. Good for them.

 

[okashira]

Should be past tense

Tesla built SOME packs for the smart EV, and the Rav4; Mercedes b-class, but they have already switched to other sources

 

[wb9k]

Should be past tense

Tesla built SOME packs for the smart EV, and the Rav4; Mercedes b-class, but they have already switched to other sources

Sounds like what GM did with A123....

 

[okashira]

Should be past tense

Tesla built SOME packs for the smart EV, and the Rav4; Mercedes b-class, but they have already switched to other sources

Sounds like what GM did with A123....

I doubt that. GM probably discovered that Iron Phosphate is not suitable for a consumer EV (poor calendar life)
of course noone is going to say that, no need to make A123's bankruptcy even worse... :wink:
Tesla packs were probably just too expensive.

 

[wb9k]

Poor calendar life my eye, our cells are among the best out there in that regard. Our packs were too expensive too. They were after our systems integration expertise, so they paid for it....for a little while. I would imagine others are after the same from Tesla. The bankruptcy was long over by the time GM dropped A123. In fact, it was over before we even started building the pack.

 

[liveforphysics]

GM probably discovered that Iron Phosphate is not suitable for a consumer EV (poor calendar life)

The two big factors in calendar life are cell voltage and temperature. LiFePO4 wins for putting minimal voltage stress on the electrolyte, so if all else were the same quality/purity/etc, it would have a longer calendar life than higher cell voltage alternatives.

The industry moved away from LiFePO4 because it's a dead-end path for applications where energy density matters. They moved away from A123's cells in particular for many reasons ranging from political BS to quality to safety.

 

[okashira]

I thought this had already made the rounds in this forum, but apparently not!

https://www.youtube.com/watch?v=pxP0Cu00sZs

summary calendar life:
LiFe < LiMn (and various hybrids) < LiCo (includes the usual LiPo and laptop cells < NCA < Lithium titanate

Sure cell voltage matters, but only when you focus on one chemistry.
It's all in the little things too, (manufacturing process, quality, additives, etc); the things you can't easily identify. I'd trust a panasonic NCA cell over a chinese NCA (if they existed) cell any-day.

 

[wb9k]

GM probably discovered that Iron Phosphate is not suitable for a consumer EV (poor calendar life)

The two big factors in calendar life are cell voltage and temperature. LiFePO4 wins for putting minimal voltage stress on the electrolyte, so if all else were the same quality/purity/etc, it would have a longer calendar life than higher cell voltage alternatives.

The industry moved away from LiFePO4 because it's a dead-end path for applications where energy density matters. They moved away from A123's cells in particular for many reasons ranging from political BS to quality to safety.

I know you're not a fan, and that's fine...you're clearly not alone. But can you name one A123 customer that has dropped A123 for safety reasons? I can't. Who makes a cell of equivalent capability that fails more safely? We still build more packs for hybrid buses than anyone. A123 always has been and remains the battery leader in the area of big industrial hybrids and EV's. With the securing of the next generation Volvo HEV bus for China (a pack that will be built in Livonia, NOT in China) and others that have announced they are staying with us for the next generation--even after looking at the alternatives anew--this doesn't appear to be changing any time soon. The cells are pretty big at the racetrack, too. So, I think a statement like "The industry...moved away from A123's cells in particular..." as though this is something that has actually happened is a tad premature. Perhaps certain corners of the EV world that once were interested in the LFP have decided it's not the cell for them, but you speak as though all the world has given up on A123 and it's just not the case. A123 is looking beyond LFP themselves because they realize it's not the be-all end-all. But maligning A123 on safety? Really?

 

[wb9k]

I thought this had already made the rounds in this forum, but apparently not!

https://www.youtube.com/watch?v=pxP0Cu00sZs

summary calendar life:
LiFe < LiMn (and various hybrids) < LiCo (includes the usual LiPo and laptop cells < NCA < Lithium titanate

Sure cell voltage matters, but only when you focus on one chemistry.
It's all in the little things too, (manufacturing process, quality, additives, etc); the things you can't easily identify. I'd trust a panasonic NCA cell over a chinese NCA (if they existed) cell any-day.

A123's powder structure gives its LFP cells performance that is far above the norm for LFP. 2,000 to 3.000 cycles before losing 20% of capacity is common for these cells. Only LTO is better in this regard (there's that lower voltage again), one reason A123 is now developing an LTO cell. They're also developing an NMC cell for the passenger car market because energy density has become king in that sector.

 

[Punx0r]

I look forward to seeing what A123 can do with other cell chemistries. They seemed to make a purse from the Sow's Ear that is LiFePO4 Just look at the other, junky, available LiFePO4 cells available.

 

[circuit]

summary calendar life:
LiFe < LiMn (and various hybrids) < LiCo (includes the usual LiPo and laptop cells < NCA < Lithium titanate

How can this be correct? I know someone who is using 26650 A123 cells, the old ones in paper sleeve. We bought those cells from China ~6 years ago. These were pulled from unknown batteries, all dirty, etc. The pack was soldered and is still used in ebike, with peaks of up to 10C. There is no visible decay in capacity.
Unfortunately I can not say that about any 18650 of other battery builds.

I believe the main concern about using A123 cells was their price and energy density. They were just too damn heavy and expensive. $75 for a 20Ah cell? Seriously? 4 times more expensive than other solutions.

 

[Hillhater]

Tesla built SOME packs for the smart EV, and the Rav4; Mercedes b-class, but they have already switched to other sources

it might be more useful if you could indicate what those other sources are !