New video – Battery tech!

Aptera Community Aptera Discussions New video – Battery tech!

Aptera Community Aptera Discussions New video – Battery tech!

  • New video – Battery tech!

  • Peter Jorgensen

    Member
    May 13, 2022 at 12:34 pm

    https://www.youtube.com/watch?v=0Klxngp4H8U

    New video is up for 41kwh battery!

  • Peter Jorgensen

    Member
    May 13, 2022 at 12:41 pm

    Looks like the 400 mile version will have a 41 kwh usable pack.

    6 modules

    416 cells per module

    2496 cells total.

    – If these are Samsung INR21700-50E battery cells then:

    5ah per cell means 0.018 kwh per cell so 44.928 kwh total. So maybe 3kwh is unusable.

    So each module is 7.488 kwh total or 6.833 kwh usable.

    I’m guessing they’ll make these packs:

    4 module (27.3 kwh) pack

    8 module(54.664 kwh) or 10 module (68.33kwh)

    14 module (95.662 kwh) or 16 module (109.33kwh)

    • kerbe2705

      Member
      May 13, 2022 at 4:33 pm

      As most EV traction packs have a buffer of between 10 and 20%, that would put Aptera’s capacity somewhere between 45 and 50 kWh. So your 44.9 figure could be right on the money!

  • Hee-Choon Lee

    Member
    May 13, 2022 at 1:14 pm

    Thanks for the heads up! Really refreshing piece of news about a critical aspect of Aptera.🙂

  • Curtis Cibinel

    Member
    May 13, 2022 at 5:23 pm

    Based on this data I projected the numbers based on the math. I am really having issues making a combination that makes the ranges come out roughly correct.

    The biggest issue is that if you assume modules will be constant having 3 in the 250 mile underperforms and 4 overperforms. By having a low pack weight overhead (15%), high battery reserve (15%) and very low base weight of 950lb (without battery or driver) others are 10% over EPA rating and the 3 module 250 mile is at only 240 miles. It could be that different packs will have different module sizes because 3 or 4 modules of this size gave either far too little or too much range. If you plugged the constants from motormatchup and used a 60 mph speed is roughly EPA the range would be more like 530 miles for this “400 mile” pack. The 1000 mile version might need as many as 18-20 modules (134 kwh) weighing 1400-1600lb.

    https://docs.google.com/spreadsheets/d/1Tuu7avKH2dS_JPk7aiP2av09a1f1WE0OvvNH6fdHpiQ/edit#gid=1285203539

    Note: Make a copy to play with the numbers – please share it if you can get closer. Only the Aptera Battery Sizes tab has these new more complex calculations. Orange fields are the numbers being fed into the calculations that can be changed. Edited with Ken’s suggestion for more battery reserve but the 400 is still overperforming but adding modules or weight changes throws the number curves off even more for the other ranges.

    Important: These numbers contain a ton of assumptions and estimates. Only the Cd and these pack details are actually confirmed.

    PS: the forum ate my comment on edit multiple times… Thankfully I always backup because it isnt the first time. Tweeked the numbers again and again to get as close to inline with intended ranges.

    • Andy Tymczyszyn

      Member
      May 13, 2022 at 9:31 pm

      They’ll go for 4 and just add a larger buffer. The shorter the range the more they’ll be hitting the high current DC, and the battery will die faster.

      If you’ve got a 600 or 1000 miles then you almost done need to even stop on a road trip to fill, just park at the hotel and charge slower overnight. Big difference with the small cell.

      • Curtis Cibinel

        Member
        May 13, 2022 at 10:04 pm

        That would be an obscenely large battery buffer and would effectively devalue the other options. To match the range curves of the others that is a huge battery reserve (30%). They might end up making the 250 mile using LFP (which would still have me evaluating if its worth downgrading because the range would be far more usable). I did the math on LFP with either easily available commodity cells 160 wh/kg or state of the art 210 wh/kg from GHT; it is definitely doable given that the shell has enough space for a crazy massive 1000 mile battery.

        • Bob Kirchner

          Member
          May 15, 2022 at 10:24 am

          One possible advantage to an obscenely large buffer is the ability to charge at full power over all or nearly all of the battery’s usable capacity, which would have real appeal in an EV with 250 miles range.

    • Russell Fauver

      Member
      May 14, 2022 at 10:09 am

      The way the modules are designed it looks like they could leave a few cells out to achieve the desired capacity. I think I remember Tesla doing that with one of their packs.

      • Curtis Cibinel

        Member
        May 14, 2022 at 10:24 am

        It seems like if they had their intended drag and amount of battery reserve (6% if you run the usable numbers vs cell specs) that the pack is overperforming. Perhaps the use of mirrors is hurting the drag or auxiliary load for screens, control is more substantial. Regardless if you assume similar factors vs the calculations for 60 mph the “1000 mile” will need a monstrously large pack with 18-20 modules and 7488-8320 cells (more than the Lucid Air); EVs have their own form of the rocket equation problem as they get heavier. The 1000 mile will also weigh about 1000 lb more than the 400 mile so I wouldn’t expect it to be as nimble.

        • kerbe2705

          Member
          May 14, 2022 at 11:15 am

          @Curtis Cibinel “…18-20 modules…”?

          Without doing any math whatsoever (just sticking to arithmetic…): If Aptera opts for a 20% buffer, the 400 mile pack would be 48 kWh, or 8 kWh per module (6 modules). Extrapolating from that, one could see the 250 mile pack at 32 kWh (4 modules), the 600 mile pack at 72 kWh (9 modules) and the 1K mile pack at 120 kWh (15 modules).

          • Curtis Cibinel

            Member
            May 14, 2022 at 11:59 am

            You would be 100% correct if batteries had no mass. Unfortunately they do (quite a lot in fact) and you need more batteries to handle the weight of more batteries (similar to the rocket equation).

            Without even accounting for bus bars, electronics or containers the extra 2170 cells of 15 modules (9 more than the 400 mile) you describe would weigh 570 lb. Packaging obviously has mass and adding batteries to offset the extra weight is the reason for 3-5 more expected modules (18-20 total). Efficiency drops due to the weight and its impact on rolling force by ~20% due to ~1000lb of extra battery pack mass. Even if everything is really massively efficient (10% extra weight over just the cells in the pack) that is 18 modules / ~800lb and ~16% efficiency difference.

            • kerbe2705

              Member
              May 14, 2022 at 9:45 pm

              See? THIS is why there need to be more unicorns involved! 🙂

            • John Malcom

              Member
              May 16, 2022 at 10:17 am

              EXTREMELY limited supply of those☹ run the cost up to high

  • Curtis Cibinel

    Member
    May 13, 2022 at 10:33 pm

    Aptera Owners Club did a video breaking things down. https://www.youtube.com/watch?v=nXNYlMqQ0Jk

  • guyf

    Member
    May 14, 2022 at 12:06 am

    There’s been a few other comments looking at the pack configurations/capacities for each model, but I’m curious to see how they manage the power draw, especially on the smaller packs.

    Assuming it is the Samsung INR21700-50E cells, each cell is rated for 9.8A continuous, or 14.7A peak. 2496 cells at 3.6V gives about 88kW continuous max load, or 132kW peak. Assuming the battery is full (4.2V) we get 103kW continuous or 154kW peak.

    Given that the 250 mile model will have a smaller pack, the maximum pack ampacity will have to be lower. The 150kW motor configuration, drivetrain efficiency losses and accessory consumption could all add up to very high power draw.

    I assume Aptera has verified with the manufacturer that the batteries are fine with the peak loads for the associated times and temperatures, but if anyone works in this area I’d be interested to know what the limits are of these cells.

    • Joshua Rosen

      Member
      May 15, 2022 at 12:27 pm

      The maximum current drawn is controlled by software, they can set the maximum acceleration to whatever is required to protect the batteries and the motors. There is no reason for all of the variants to have the same acceleration. If I had to guess the 250 mile version and the 1000 mile version will both be slower than the 400 and 600 mile versions, the 250 because it’s current limited and the 1000 because of weight. As for which will be quicker between the 400 and 600, it’s anybody’s guess, I wouldn’t be surprised if they split the difference, the 2WD 400 will be quicker than the 600 mile version because of weight but the 600 mile AWD will be quicker than the AWD 400 mile version because the extra motor means that it will need 1.5X as much current to max out the motors. This is all just wild ass guesses on my part, in addition to the limits caused by the batteries and motors there is also the controller and the cooling system to consider, Aptera has the numbers so they know what the limits are but they’ve only released a subset of the numbers for the rest of us. Also because it’s software controlled they can make choices for other reasons than just hardware limits. For example they could choose to nobble the quicker variants so that they all have the same performance. They could also choose to nobble the cars so that they can copy what Tesla does with Acceleration Boost. For those of you who don’t own a Tesla, Acceleration Boost is a $2000 option that allows you to cut .5 second off of the 0-60 time on the Models 3 and Y. It would be wise for Aptera to do the same, almost nobody needs the 3.5 0-60 of the AWD, limit it to 4.5 seconds, which is still too quick for my tastes, and sell an Acceleration Boost software upgrade that gets you to 3.5. For those who need 3.5 seconds it will be worth the price and and for Aptera it will be more money in their pockets.

      • John Malcom

        Member
        May 15, 2022 at 1:19 pm

        All musing at this point. Until Aptera announces otherwise, we have to accept what they have announced. From the sales and marketing perspective Aptera must deliver against announced performance lest they be accused of bait and switch.

        Up charges for better anything would provide an opportunity to recoup planned revenue from inflation, but not until they have a foothold in the market.

    • Curtis Cibinel

      Member
      May 15, 2022 at 1:38 pm

      This all assumes that the Samsung INR21700-50E is the one and only cell. From the video we seem to have different kinds in view. Different cells generally have different nominal capacity, costs and discharge rates; weights and voltage are very constant. It is possible that the high capacity slow discharge samsung inr21700-50e will be for some large packs and others will use different cells (cheaper with faster discharge). The samsung INR21700-40T might be a good choice for the 250 mile since the extra weight of the smaller 4,000 mah (vs 5,000) capacity wont be a big deal and it can discharge at 30A (plenty to feed the motors 150KW even when nearly depleted). If they are going outside samsung other brands make cells like the LR2170SF which are cheaper and balance capacity and output amps (4500mah / 13.5 amps).

      The selection of the cells is a critical balance of engineering and economics; this is not simple and the answer could differ by pack size or even selection of AWD. Aptera has a team of very smart people evaluating the options. Depending how much discount they get at wholesale (I’d assume ~20%) the cells alone could still make up about 1/3rd of the cost of the Aptera.

      • John Malcom

        Member
        May 15, 2022 at 3:43 pm

        Agree! Thanks for sharing your technical insight with us.

        It is important not to get fixated on one type of cell at this point. Cost, performance, durability and many other factors go into the evaluation and selection of batteries.

        I agree too, that smart people are working on battery engineering (We have recently seen them) and am confident that they will be able to select the most cost effective and efficient choice especially if may account for 1/3 of the p[rice of the vehicle.

      • Paul Kirchner

        Member
        May 16, 2022 at 10:23 am

        In the video, Aptera Owner’s Club thought the battery was a 50G, not an E.

        • Curtis Cibinel

          Member
          May 16, 2022 at 11:02 am

          Good catch. I had trouble finding specs on the 50G and had read something that said they were the same. Looking closer it appears while they are very similar but 50G is a hair better and notably has more cycle life. I suspect the G may be a slight refresh of the E. Regardless guyf is correct that small packs of these cells would be able to provide full power to the motors and these cells are a super expensive component.

          Finding scale wholesale prices is understandably nearly impossible but 10-15% better than prices for 1000+ cells listed on sites is probably a reasonable guess which is why the cells would be a huge part of the vehicle cost. The 400 mile version with the cell count they described is $9.5K just in cells if they can get them for $3.80 wholesale; this number is likely wrong but it should within +- 10%.

  • Patrick Liebknecht

    Member
    May 14, 2022 at 3:03 pm

    Daniel said “now we have to test to see if our solar panels will charge the batteries”

    Seriously ? Am I the only one who heard that ?

    • Curtis Cibinel

      Member
      May 14, 2022 at 3:08 pm

      They designed as subassemblies. Actually charging should be trivial but is an “integration test”. Don’t lose sleep any problems will be control related; the design is sound

    • Markus Schmid

      Member
      May 15, 2022 at 3:24 am

      Humorous remarks always bear the risk of getting misunderstood, especially when lacking the possibility of swift verbal interaction as it is the case with internet content.

    • Alain Chuzel

      Member
      May 15, 2022 at 6:21 am

      It may be you were the “only one who heard that”. My bet is most heard what Daniel actually said (at 1:25 of original vid/not Aptera Owner’s Club vid) which was “how the solar charging integrates into our battery pack”.

  • John Malcom

    Member
    May 13, 2022 at 5:22 pm

    A lot of good work on your part.

    With only two of the factors confirmed at this point I wouldn’t be concerned about the calculation coming out “Right” not even sure the information provided is final. Still a lot of work to do and things can/will change.

    Still a lot of progress since Luke held up a single 2170 cell in the first battery maker video. Now a veritable army of young engineers working on battery packs.

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