Announcement

Collapse
No announcement yet.

lithium maganese cells

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • lithium maganese cells

    Does any one have any information regarding lithiun maganese battery cells. I'm using lifepo4, was about to order some more when the supplier offered me great prices on lithium maganese cells, half the price of lifepo4. Had a bit of a look around about them and they seem to be much better the lifepo4, other than they don't have the same energy density.

    Any info would be appreciated before making a descision. Thanks.

  • #2
    I know a bit about then, enough to know this raises all kind of Red Flags.

    First there is no less expensive lithium battery than LFP. There is no safer lithium than LFP. So when someone offers you a lithium chemistry that is twice the cost of LFP less than LFP means there is something very wrong. If I had to guess it is all the batteries Nissain got stuck with they used in the LEAF, when they had to change th edesign because they were dying in two years and now people bought them up for pennies on the dollar trying to find suckers to buy them.

    Secondly Lithium Magnese is a OK battery with high energy density, but that high energy density makes them unstable and like Lithium cobalt are dangerous and have a bad habit of catch fire if careful thermal management is not used in a BMS. All EV's use extensive Thermal Management, no solar system has any kind of BMS made for lithium.

    Lastly like Leaf owners learned the hard way, Lithium Magnese only last a couple of years. There is no longer lasting, safer, or inexpensive lithium out there than LFP.
    MSEE, PE

    Comment


    • #3
      That's interesting, haven't read anything like that. This is what I've read about them at a number of sites, but yet to find some real information on them and have met someone who has been using them for a number of years and says they are ok.

      http://lithiuminvestingnews.com/6894...reamliner-787/

      "Lithium-manganese batteries may only have about two-thirds the capacity of their lithium-cobalt counterparts, but this type of battery is considered much safer in terms of thermal stability. Lithium-manganese batteries are used in hybrid and electric cars such as the Chevy Volt, as well as in e-bikes, power tools, portable electronics and in medical applications. Lithium-manganese batteries boast about 50 percent more energy capacity than lithium-nickel-manganese-cobalt batteries. This particular chemistry can also be designed for either optimal longevity, high specific power or high capacity."

      http://data.energizer.com/PDFs/lithi...oxide_psds.pdf

      Comment


      • #4
        I agree they are safer than LiCo, but still need Thermal Management. For solar LFP is the ticket as they require no thermal management, half the cost, and last much longer. Just makes it a no-brainier. LFP is on the low side of energy density of roughly 100 wh/Kg compared to 120 to 150 for magneses and 200 plus for LiCo, but it is that higher density that makes them unstable. High density is not a requirement for solar, long life, cost, and safety are the most important factor for solar and no better solution than LFP. Heck even DIY EV types like myself use LFP in my golf cart.
        MSEE, PE

        Comment


        • #5
          Any chemistry other than LFP is the wrong application for solar.

          On a scale, the lineup is like this from most stable, least density (large) to least stable, most density (small).

          LiCo02 - least stable. smallest / highest power density. 3.7v nominal
          LiNmC - middle of the road. 3.7v nom
          LiFePo4 (LFP). Most stable. Largest / least power density [B]3.2v[/B] nominal.


          There are varying chemistries in between, and special-sauce additives that are all competing for investor's money. LFP is yesterday's news - but that doesn't mean it is bad! LFP is greedy - that is it doesn't actually like giving up oxygen atoms, but all the rest do so willingly.

          As you go up the scale, you are paying for super high-discharge rates and tiny sizes, something like C10 or more if necessary. Nobody is going to need that capability with solar. In fact, even the LFP's could be considered somewhat too-good, that is nobody who designs a bank properly is going to exceed 0.5C.

          Also note that ONLY LiFePo4 is a nominal 3.2v cell, whereas all the rest are 3.7v nominal, and thus require different charging voltages and EXTREME charge voltage monitoring. Take one of the non-lfp cells beyond 4.2v, like to 4.3v and you have a really bad situation. Take an lfp slightly above 3.6v and you incur cell damage, but not catastrophe - that takes about 30v overcharge. See the difference in safety right there? Note that I'm not advocating being careless with lifepo4 either.

          Fit the battery to the need. There is no need for any power-density higher than LFP in a solar setup. Topping that off is that they are the SAFEST of all the lithium chemistries out there since they are at the bottom of the list. They are basically what agm's want to be when they grow up.

          The best advice I can give is to STOP learning from investor sites or news media outlets about lithium. They are paid to SPIN the facts, if they actually know them. Listen to the professors and others in academia who actually built them and used them instead. Prof Jay Whitacre comes to mind.

          This video from Prof Jeffrey Dahn is invaluable. It goes beyond just EV cars and gets to the chemistry questions.
          https://www.youtube.com/watch?v=9qi03QawZEk

          Now we're talking.

          Comment


          • #6
            Thanks and interesting. The lithium manganese Ive seen, been offered and interested in, are only 3.2-3.4v, half the price of lifepo4 and guaranteed for 2500 cycles. They are used in Ev's and also in off grid systems and when you look at the growing number of lithium variants, they seem to be close to the top of the range along side lifepo4. Price is big thing for most people, so it's very relevant to investigate all options before deciding a direction.

            I'm one of those people who likes to understand the entire technology and don't just listen to spin or those with bias to certain energy directions. To me everything is worth looking at and researching, so I get the best outcome soft the future.

            It's a pity there is not enough readable information on the different lithium technologies, if there was we would be able to make better informed decisions, rather then have to stumble along trying to disseminate all the garbage put up by those with vested interests.

            Comment


            • #7
              Originally posted by tasman View Post
              The lithium manganese Ive seen, been offered and interested in, are only 3.2-3.4v, half the price of lifepo4 and guaranteed for 2500 cycles. They are used in Ev's and also in off grid systems and when you look at the growing number of lithium variants, they seem to be close to the top of the range along side lifepo4. Price is big thing for most people, so it's very relevant to investigate all options before deciding a direction.
              Let me guess, they are advertised as new Nissan Leaf Modules from 2012 right? Along the lines of [B]this ad[/B] right?
              MSEE, PE

              Comment


              • #8
                Not a very good guess, never seen that ad and the cells I was offered, are brand new straight of the line from the Chinese manufacturer and 50-100ah cells.Take $100 of the ad price, the fact they come in 100ah and 3 year warranty, so nothing like the ad rip off.

                Comment


                • #9
                  Originally posted by tasman View Post
                  Thanks and interesting. The lithium manganese Ive seen, been offered and interested in, are only 3.2-3.4v, half the price of lifepo4 and guaranteed for 2500 cycles.
                  Ah, ok that would be either GBS or something similar. GBS cells are lifepo4, BUT just a *dash* of manganese thrown in, making them LiFe(Mn)Po4. Still basically 3.2v nominal lfp cells. This added ingredient obtains results that they like, much like Winston, which are also LFP, but use yttrium, making them LiFe(Y)Po4.

                  At the end of the day, we are still dealing with 3.2v lifepo4 for the most part. One other biggie is CALB, which uses no additional ingredients, but refines the phosphate for ever increasing current rates.

                  Still, this is wholely unlike the 3.7v nominal cells which are not LFP, which may contain large amounts of manganese, like LiNMc which are usually small cylindrical types used in powertools etc. Avoid those for your application.

                  I like and use GBS cells in my own solar application.

                  There is no real trick to maintaining LFP. The rules are pretty easy:

                  1) Don't charge any cell higher then 3.6v
                  2) Don't discharge any cell lower than 3.1v.
                  3) You don't NEED to always fully charge them, (of course you need to have calculated your capacity right in the first place to do this.)

                  Comment


                  • #10
                    If they are GBS, they are not less expensive than Calb. I do not know of a less expensive LFP than Calb. Having said that I do have GBS batteries in my cart and like them. I knew something had to be amiss because Lithium Manganese are more expensive than LFP. Only cheap Manganese batteries out there are the Nissan Leaf model years 2011 and 2012 that had a recall. It is Nissan's stock they got caught with, and sold to recover some losses EV shops bought them off Nissan for pennies on the dollar, disassembled the battery packs, removed the modules, and sell them to the unknowing public as new. Not really a bad deal, but at least folks should know what they are getting.
                    MSEE, PE

                    Comment


                    • #11
                      What makes lithium batteries a bit confusing for newcomers is the industry just lumping all lithium-based batteries together without knowing that there are differing characteristics and charge routines.

                      It is kind of like walking into a battery retailer and simply saying " I need a lead-acid battery please". Plenty of ways to get ripped off if you don't know if you need a starter battery, deep discharge, flooded, agm etc etc.

                      Same goes for lithium. To add to the confusion, I have a few small radios that now use a single LiNMc battery like Tenergy and so forth, which are 3.7v cells and NOT lfp. These very same cells go into automotive jump-starter packs, yet the radios themselves only draw something like 75ma in operation. The capability of those cells in the radio application are going to waste, but are cheap enough not to matter. I would have preferred the lower voltage LFP if I was the engineer, but they went with these.

                      So I can see the confusion when someone considers lithium for a solar setup, and not differentiating between the 3.2v lifepo4, and all the others (3.7v different chemistries) when there is really a mis-application in some consumer devices like my radios. Presumably they did that for that tiny bit of higher voltage and slightly smaller form factor.

                      All the major players like GBS, Winston, CALB etc are more than good enough for our needs. If anything else, I'd recommend GBS to newcomers purely because they come with cell-top covers to enhance the safety factor from the get-go - of course you need to actually use them!

                      Comment


                      • #12
                        Originally posted by PNjunction View Post
                        If anything else, I'd recommend GBS to newcomers purely because they come with cell-top covers to enhance the safety factor from the get-go - of course you need to actually use them!
                        As disclosure I have GBS cells, but they are used in a Golf Cart. GBS is good, but is a High-End LFP product. CALB is trusted and the most bang for the buck even though they just went up in price.

                        Looks like LFP cells have bottomed out, and now prices are rising. A month ago you could get Calb cells for 34-cents per watt hour. Today just a hair shy if 40-cents or a 15% increase.
                        MSEE, PE

                        Comment


                        • #13
                          Originally posted by Sunking View Post
                          Let me guess, they are advertised as new Nissan Leaf Modules from 2012 right? Along the lines of [B]this ad[/B] right?
                          I use Leaf modules in my off-grid cabin. 70 of them for a 35kWh battery of which I use approx. 25kWh. 7S10P which is a 14S battery since the modules are 2S2P.

                          Charging safety is not a problem. My Outback FM80 is set to 57V which for the 14S battery is 4.07V per cell. The Orion Jr. BMS controls a charger safety relay that cuts the PV input to the FM80 if any cell exceeds 4.10V. The BMS also continously balances above 3.900V for any cells 10mV higher than the lowest. Also the BMS controls a load safety relay that turns off the inverters and most 12V loads if any cell dips below 3.4V.

                          Thermal management is not neccessary in Norway, we never get Arizona temperatures here (max ~25C where the cabin is located). Also I never draw more than a little less that 0.2C from the battery bank (2x3kW inverters + a 360V 12V DC-DC). Charging is 5kW max from generator or 2.6kW max from solar (8xSunpower 327W).

                          Price paid for the modules was $3750 for 35kWh, or a little over $100/kWh. What can compete with that, price wise?

                          2015-04-25 23.39.41.jpg

                          Comment


                          • #14
                            Originally posted by jkirkebo View Post
                            I use Leaf modules in my off-grid cabin. 70 of them for a 35kWh battery of which I use approx. 25kWh. 7S10P which is a 14S battery since the modules are 2S2P.

                            Charging safety is not a problem. My Outback FM80 is set to 57V which for the 14S battery is 4.07V per cell. The Orion Jr. BMS controls a charger safety relay that cuts the PV input to the FM80 if any cell exceeds 4.10V. The BMS also continously balances above 3.900V for any cells 10mV higher than the lowest. Also the BMS controls a load safety relay that turns off the inverters and most 12V loads if any cell dips below 3.4V.

                            Thermal management is not neccessary in Norway, we never get Arizona temperatures here (max ~25C where the cabin is located). Also I never draw more than a little less that 0.2C from the battery bank (2x3kW inverters + a 360V 12V DC-DC). Charging is 5kW max from generator or 2.6kW max from solar (8xSunpower 327W).

                            Price paid for the modules was $3750 for 35kWh, or a little over $100/kWh. What can compete with that, price wise?

                            [ATTACH]7220[/ATTACH]
                            Very cool. These are new cells?

                            Comment


                            • #15
                              Originally posted by donald View Post
                              Very cool. These are new cells?
                              No, I got them from wrecked Leafs. There are maybe 20,000 Leafs in Norway and there is a steady supply of crashed ones. There isn't much demand for complete battery packs so they can usually be gotten at reasonable prices from the wrecking yards.

                              Comment

                              Working...
                              X