Manganese Spinel Li ion Batteries 101

[ydnas7]

Manganese Spinel Li ion Batteries are the dominant form of automotive Lithium ion battery, used in EVs, PHEVs and HEVs, ie LEAF, Volt, Hyundai/Kia hybrids etc. This is due to its desireable safety, cost and history.

The general principle is that by doping -> capacity is traded for robustness
ALL Commercial Manganese Spinel cathodes are doped, the reduction in capacity is about 20% below theoretical non doped manganese spinel. This is primarily achieved by slightly elevating the Li content, it also is achieved by adding small amount of Al, Mg, Ti, Ni etc.

The robustness is improved, which generally means temperature tolerance, cycle life, rate capacity and safety all improve at the same time, BUT energy capacity is reduced and the supply is more niche.

Blending a nickel based cathode (NCA, NMC) into a manganese spinel mix improves both robustness and energy capacity, but then adds further safety issues and higher costs. Nissan LEAF cells and Mitsubishi i cells are both blended cathode powder cells. (perhaps Nissan is using a layering trick, to improve short duration power)

Manganese Spinel batteries longevity is very dependant upon electroyte, long life LTO batteries often are Manganese Spinel based, but because they have a different -ve anode, they can use a different electroplyte, and its becasue they use a different electrolyte that they are so robust. When Nissan states they have tweaked electroylte, it means that there could be significant improvement...all else being equal.

 

[EVDRIVER]

?? Please post this in the new battery tech thread.

 

[ydnas7]

this is not about new batteries, its about past and current batteries, the choices that were made, why they there made and the options that were available.

It may stray onto near term future possibilities, but its meant to be primarily a reflective thread, about in production technology.

commodity cathode
An example is TRONOX 100 http://www.tronox.com/wp-content/uploads/2012/04/TR-LMO-100-brochure.pdf" onclick="window.open(this.href);return false;
its representative of mass produced cathode, and as such if it was blended with a little NCA is probably similar to LEAF tech. which is itself somewhat more robust than LG cells

a speciatly cathode - patented dopants
TRONOX 200 http://www.tronox.com/wp-content/uploads/2012/04/TR-LMO-200-brochure.pdf" onclick="window.open(this.href);return false;. Note its tests are at 60degress celcius.

 

[RegGuheert]

...is probably similar to LEAF tech. which is itself somewhat more robust than LG cells

Can you provide any documentation to support this claim? In another thread we are discussing the real possibility that LG used ceramic-coated separators while Nissan did not. That difference apparently could result in the LG battery having better high-temperature characteristics.

Am I off-base here? If so, please shed some light on the differences between the robustness of the two batteries. TIA!

 

[DanCar]

What is the other thread?
http://www.bizjournals.com/charlotte/blog/power_city/2013/08/analyst-polypore-still-a-supplier-for.html?ana=RSS&s=article_search&utm_source=dlvr.it&utm_medium=gplus" onclick="window.open(this.href);return false;

At the end of the article:
“Our sources indicate the new battery design will include single-layer polypropylene separator from Polypore.” The new separator will include an aluminum oxide ceramic coating, which is used to resist material breakdown from high temperatures

 

[mwalsh]

At the end of the article:
“Our sources indicate the new battery design will include single-layer polypropylene separator from Polypore.” The new separator will include an aluminum oxide ceramic coating, which is used to resist material breakdown from high temperatures

Also already being covered elsewhere. Please try to keep up:

http://www.mynissanleaf.com/viewtopic.php?f=4&t=13192&start=425" onclick="window.open(this.href);return false;

 

[DanCar]

Also already being covered elsewhere. Please try to keep up:

http://www.mynissanleaf.com/viewtopic.php?f=4&t=13192&start=425" onclick="window.open(this.href);return false;

Do you really expect everyone to read every thread? Please try to be more cordial.

 

[mwalsh]

Do you really expect everyone to read every thread?

Yes. Or at least do a quick search first:

http://www.mynissanleaf.com/search.php?keywords=ceramic+separator&terms=all&author=&sc=1&sf=all&sk=t&sd=d&sr=posts&st=0&ch=300&t=0&submit=Search" onclick="window.open(this.href);return false;

In fact, in the post before yours RegGuheert even TELLS you it's being discussed elsewhere.

 

[ydnas7]

...is probably similar to LEAF tech. which is itself somewhat more robust than LG cells

Can you provide any documentation to support this claim? In another thread we are discussing the real possibility that LG used ceramic-coated separators while Nissan did not. That difference apparently could result in the LG battery having better high-temperature characteristics.

Am I off-base here? If so, please shed some light on the differences between the robustness of the two batteries. TIA!

which LG batteries are being discussed, PHEV batteries or EV batteries, as the more robust a battery is in power delivery, the more robust it tends to be in longevity requirements. Renault is happy to lease the Kangoo without cooling (Nissan NEC cells) but the ZOE has cooling (LG cells).

Generally ceramic-coated separators are used to improve safety, no mention of longevity. http://industrial.panasonic.com/www-data/pdf2/ACI4000/ACI4000CE25.pdf" onclick="window.open(this.href);return false; LG's implementation does somewhat improve battery life but I wouldn't expect anyone else implementation of cermic-coating to improve longevity (unless its specifically designed to)

LG, Mitsubishi, Nissan are all using Mn based Li ion batteries. Mitsubishi and Nissan even use cathode from the same supplier. But the cell factories are very different. Nissan is stacked like a book, Mitsubishi is wound like a flat spindle, and LG is kinda different using a stacking/winding combo, there is also a Z stack that LG was earlier thought to use, but don't. http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2012/energy_storage/arravt001_es_koo_2012_p.pdf" onclick="window.open(this.href);return false;

A point is, the performance of these batteries is a tuneable tradeoff/compromise/optimise. So far, for EVs, Mn spinel class batteries, the global sales are going to ambient cooled cells, but for layered cell (ie Tesla) class sales are to refrigerated cells. I suspect the primary driver is both cases is safety and what the battery supplier requirement for sale.

 

[AndyH]

A point is, the performance of these batteries is a tuneable tradeoff/compromise/optimise. So far, for EVs, Mn spinel class batteries, the global sales are going to ambient cooled cells, but for layered cell (ie Tesla) class sales are to refrigerated cells. I suspect the primary driver is both cases is safety and what the battery supplier requirement for sale.

Be careful here as Tesla are not using LiMn cells - they're using commodity LiCo cells. These are the cells with metallic lithium and a propensity to burn when abused. These cells NEED active thermal management to be safe - the LiMn do not.

Yes, they can all benefit from thermal management for other reasons - like reducing the degradation rate in hot climates - but there are other primary reasons for Tesla's use of coolant in the battery boxes. (But this, too, has already been covered in the other thread. )

 

[surfingslovak]

Yes, this was true with the Roadster. I heard from an owner that on occassion the car would throttle AC in the cabin to ensure that the pack was properly cooled. While the recent Plug In Anerica study has shown that these cells are aging well and will likely surpass the expectations placed on them, it's clear that the pack is cooled aggressively because the cell chemistry and the pack design (large enclosed block with a small surface area) require it. Tesla has reportedly switched to NCA as their battery chemistry of choice with the Model S. They claim that these are automotive-grade cells in a commodity 18650 packaging. That said, the recent well-publicized fire in Kent, WA following an accident involving road debris highlights how important safety is as a factor for favorable public reception of EVs. It would also appear that the cells Tesla is using in the Model S are still more volatile than manganese spinel, which all major automakers seem to prefer. I believe that no fires involving manganese spinel cells have been reported aside from the Chevy Volt incident, which was supposedly triggered by a leaking coolant in a crash-tested vehicle several weeks after it was placed in storage (there was another discussion on that topic). I'm not sure if it's worth continuing this thread though. Perhaps it should be merged into the other one mentioned above by EVDRIVER. Another alternative is to make its title more unique. As Andy said, manganese spinel has been discussed many times before, and if this thread is supposed to be an FAQ, it would be good to collect the links to previously posted information as a summary in the first post.

 

[RegGuheert]

...is probably similar to LEAF tech. which is itself somewhat more robust than LG cells

Can you provide any documentation to support this claim? In another thread we are discussing the real possibility that LG used ceramic-coated separators while Nissan did not. That difference apparently could result in the LG battery having better high-temperature characteristics.

Am I off-base here? If so, please shed some light on the differences between the robustness of the two batteries. TIA!

which LG batteries are being discussed, PHEV batteries or EV batteries, as the more robust a battery is in power delivery, the more robust it tends to be in longevity requirements.

Thanks for the reply!

We were comparing the LEAF's longevity characteristics with those of the Volt. What I think you are saying here is that since the Volt battery has a power capability which is roughly double that of the LEAF (~130% the power with 2/3 the battery capacity), it should also have better longevity. Is that correct? I can see some merit in that concept, but at the same time I assume the Volt battery experiences both higher rates of discharge and higher depths-of-discharge (given the same application below 40 miles per day). Of course that usage difference will affect cycling losses mostly and the issue with the LEAF seems to be more with calendar losses. Do you think the ceramic separator affects calendar losses, or not?

Renault is happy to lease the Kangoo without cooling (Nissan NEC cells) but the ZOE has cooling (LG cells).

I'm convinced marketing decisions by automotive companies cannot be used as a gauge for the appropriateness of a given technology for a given application. Only real-life results can answer that question.

Generally ceramic-coated separators are used to improve safety, no mention of longevity. http://industrial.panasonic.com/www-data/pdf2/ACI4000/ACI4000CE25.pdf" onclick="window.open(this.href);return false; LG's implementation does somewhat improve battery life but I wouldn't expect anyone else implementation of cermic-coating to improve longevity (unless its specifically designed to)

Here is a link to the discussion of the separators used in the Volt. As you say, the trade name of the separator material has the word "safety" in it, so assumedly that is the primary function. But if you read back a few pages in that thread, you will see that NEC (and possibly AESC) is moving to ceramic separators for the specific purpose of improving the ability of their battery to withstand more heat.

A point is, the performance of these batteries is a tuneable tradeoff/compromise/optimise. So far, for EVs, Mn spinel class batteries, the global sales are going to ambient cooled cells, but for layered cell (ie Tesla) class sales are to refrigerated cells. I suspect the primary driver is both cases is safety and what the battery supplier requirement for sale.

IMO, vehicle cost and battery lifetime are also very significant factors which will determine which battery works in which application. The LEAF approach is not working out in hot climates and Nissan is making adjustments. Time will tell if it will be enough.

I've always felt that ambient cooling is the best solution given appropriately heat-tolerant battery technology. But can Mn-spinel-class batteries really fit that requirement? The LEAF batteries have not yet demonstrated that it can. Even in the coolest climates in the U.S. the calendar losses appear to be dominant except for the case of very-high-mileage applications. What that means is that these vehicles likely will not achieve a good lifetime in low-mileage applications, even in cool climates.

 

[AndyH]

Let's set the wayback machine to 2010:

http://www.mynissanleaf.com/viewtopic.php?f=9&t=456

http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2009/energy_storage/es_07_alamgir.pdf

Calendar aging is expected for all lithium battery types. LiMn was selected for further development because it was less expensive than other options, not because it gives the best cycle life or calendar life - it gives neither. The pros/cons of common variants are listed in the linked presentation.

 

[AndyH]

While the recent Plug In America study has shown that these cells are aging well and will likely surpass the expectations placed on them...

Thanks - I think the PiA studies are exciting.

I look forward to seeing numbers from Smart, as they're not only using LiMn with ceramic separators, but they have liquid heating/cooling and the V03 refrigeration option for their battery.

This should give us a decent pool of data with which to compare Nissan's current and hot-weather battery and their decision to go with passive cooling.

 

[ydnas7]

Most EVs sold in world are ambinet temperature control or available as ambient temperature cooled.
Presumably, a factor is automaker's ownership of battery production.

Nissan LEAF ~ 90,000 sold, only available with ambient temperature control. ~50% partial ownership of battery production

Mitsubishi i ~ 30,000 units sold, basic model is ambient temperature control, QC model has refrigerated cooling for QC, cold temperature has heating. simple to modify for cabin cooling to battery, see http://myimiev.com/forum/viewtopic.php?f=14&t=1515&start=10" onclick="window.open(this.href);return false;
Mitsubishi/s has partial ownership of battery production.

Tesla model S ~25,000 units sold, all models have a strong refrigerated, liquid cooling. Chemistry is a layered cathode (NCA). Nil ownership of battery production, (Panasonic has minor ownership in Tesla)

Renault Kangoo ZE ~10,000 units sold, only available with ambient temperature control. ~42% ownership of Nissan which has a ~50% partial ownership of battery production. http://www.arro.org.au/_dbase_upl/ERG_Kangoo_ZE_ph2_nov_13.pdf" onclick="window.open(this.href);return false;

Twizy is kinda like an electric quad bike, presumably with cooling for battery but not for vehicle occupant.
Renault ZOE is catching up to Kangoo ZE sales, ZOE uses LG cells and has refrigerated cooling for cells, No ownership of LG cell production by Renault.

other EVs sales todate are mostly compliance, and small volume.
so of the the world's top 4 EVs, 3 are ambient temp cooled. those 3 are Manganese spinel based.

PHEVs is another matter...

 

[ydnas7]

page 24 http://my.stust.edu.tw/sysdata/74/19374/doc/1440a2c5997808f6/attach/936764.pdf" onclick="window.open(this.href);return false;
LMO 231.7 gram,
LNO 49.7 gram

 

[Nubo]

page 24 http://my.stust.edu.tw/sysdata/74/19374/doc/1440a2c5997808f6/attach/936764.pdf" onclick="window.open(this.href);return false;
LMO 231.7 gram,
LNO 49.7 gram

Interesting. That presentation puts the AESC cell cost below $400/kWh.