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Featured Discussion: NexPower V3 Sodium-ion Battery Announcement

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by mudder, Jul 4, 2024.

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  1. fuzzy1

    fuzzy1 Senior Member

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    I haven't followed all of this particular topic. But considering your posting history on previous topics, I sure hope Jack has better witnesses lined up.
     
  2. mudder

    mudder Member

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    More feedback on the prototype unit I've inspected:

    The "BMS" is nearly identical to the V1 unit I reviewed previously. Specifically, there is no supervisory control method... still just using a voltage comparator fixed to ~3.52 volts. When active, each individual discharge resistor pulls ~120 mA (sinking into a 33 ohm load).

    Fortunately the Signal Soother circuitry isn't present on the V3 hardware. Good riddance. However, there's still no per-cell knowledge anywhere in the system.

    Airflow isn't stellar, and is non-uniform due to cells just being glued together. Specifically, there's no mechanical member that separates the cells. The V3 announcement video shows what I'm talking about @7:34. Here's a screen grab showing how close the cells are in their model:
    [​IMG]

    In addition to poor airflow, this close spacing (some cells are actually touching) poses a short circuit risk, as cells with different voltage potential are only separated by a couple layers of heat shrink. Wearing through the heat shrink is possible due to lacking mechanical support which could lead to rubbing. I would like to see more space, and also mechanical support members between cells. There's certainly room inside for this, as both sides are stuffed with foam (probably to force airflow through the small gaps between cells).

    The "BMS" wires route directly over unmeasured cells... there's an effort made to place kapton tape between the wire and the cell, but there are sharp radii between the wires and cylinder corners. I'd like to see the wires routed elsewhere. I can actually see the wear from whatever is pushing against the outer enclosure when installed in the car.

    The cell terminals are still soldered.
    The busbars are still too thin.

    With the pack initially resting at 228.4 volts, charging at 10 amps immediately raises pack voltage to 233.1 volts.
    Therefore, total pack ESR(charging) is 470 mOhm. This is a single data point, but we can still predict the general heat generation inside the pack under load. For example, discharging at 125 amps will theoretically self-heat the pack at an astonishing 7.3 kW! That's ~105 watts heat generated inside each cell under heavy assist. Not great.

    Notes:
    -ESR is non-linear, and will increase as current increases. In other words, my 10 amp test is erring in NexPower's favor.
    -My ESR measurement includes all QTY70 cells, plus all interconnects. I subtracted out the 1.24 mOhm fuse I placed between the modules... because I like fuses.
    -I don't actually know the Prius' peak assist and regen current values. However, my understanding is the gen3 Prius' electric motor can deliver 27 kW... I assume it can do that when Vpack = 240 volts, which is the value I used in the above calculation. Again, this (probably) errs in NexPower's favor.
     
    #62 mudder, Jul 30, 2024
    Last edited: Jul 30, 2024
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  3. mudder

    mudder Member

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    I'm done discussing potential legal matters for now, and will ignore further correspondence regarding said topic. If Jack wishes to serve me, he has my contact info. I will of course publicly disclose any such legal complaint as soon as I receive it. Until then, let's focus on the technical merits.

    They certainly do. My prototype unit is less than three months old. I would certainly hope that the final design was mostly locked in that close to release.

    Counterpoint: If Jack's latest V3 hardware is better than my prototype, it would make sense that Jack would want me to review that hardware instead. I can only review the product that's in front of me. If @jacktheripper agrees to send me new hardware (that I will pay for), I will review it instead. Information wants to be free. I am just the messenger.
     
  4. fuzzy1

    fuzzy1 Senior Member

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    I seem to remember the Gen3 battery power limit being in the 26 or 27 kW range, temperature permitting. The rest of the power to MG2 must come from the ICE via MG1.
     
  5. mudder

    mudder Member

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    Thanks for the info. OK I will update my original post with your estimate.
     
  6. mudder

    mudder Member

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    OK, here are my concerns with the V3 NexPower prototype I received today. As noted in the video, this prototype was manufactured in 2024MAY.


    FYI: I am aware that the printed pictures I showed in this video are washed out. See:
    -post#49 for the cell discharge curve, and;
    -post#54 for the cell voltage measurements.
     
  7. Xeico

    Xeico Junior Member

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    This is just trash.
    Looks like someone is unteachable.
    Is it 70 cells in series?
    Can you take a photo of how they connect the cells together?
     
    #67 Xeico, Jul 30, 2024
    Last edited: Jul 30, 2024
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  8. AzusaPrius

    AzusaPrius Senior Member

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    "I would like to see more space, I would like to see wires routed different" jesus christ I could only imagine what you put your parent through.

    How about we would like to see something from you, a prototype or finished product.

    All we get is you complaining about a working product and how you would have it done, yet you are not making anything.

    Bless your broken heart
     
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  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Nah, what's funny is pretty much every post you write.......I was a firm believer that you had an unusual comprehension of reality, even prior to these battery threads. All you've done since, is guarantee it. You seem to believe that if you repeat the same ignorance over and over, it will become true.
     
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  10. BuckleSpring

    BuckleSpring Junior Member

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    Thanks for the info.
    Some perspective from my non-EE POV:
    • Shipping the prototype units to an end user with the service disconnect bypassed is so bad I can't even put into words. Even if this was made known to the beta tester, that's a critical safety device, what if a beta tester were to (as an example) have their AC compressor serviced/replaced by a tech who didn't know the disconnect was bypassed? Or, God forbid, a Beta tester was involved in an accident and the police/firefighters needed to disconnect the HV system. It seems like such a legal liability that I couldn't imagine shipping that hardware to any end user.
    • I still don't really see the point in the non-GT pack. I await further info (from Jack or otherwise) about usable capacity of both compared, cooling properties, etc. From my perspective, ignoring usable capacity and heat and other possible deficiencies, the serviceability of the non-GT pack just isn't worth the tradeoff for.... a 15 minute quicker install time? I highly question the RMA strategy for this pack.
    • The only real/main advantage to the non-GT pack that I can see is using the cylindrical cells vs pouch cells. If done properly, there's nothing wrong with a pouch cell, but I do worry about an individual pouch puffing up over time (especially with some questionable factory QC or subpar BMS), what the clamp situation looks like, etc. Even with that being said, the serviceability of GT seems like a no-brainer comparatively.
    • The man-in-the-middle "BMS" is pretty good IMHO. The "BMS" it shipped with may not be up to snuff, but like you said, someone could fairly easily design a proper BMS to take its place, assuming the mechanical deficiencies on the final product are resolved
    • I hope the mechanical deficiencies are sorted by the ship date. A honeycomb separator you pointed out wouldn't be hard to manufacture. I can't imagine these are flying off of the shelf and they're shipping dozens a day, and judging by their previous products/prototypes, Jack and team probably have some kind of small 3D print farm, this seems like a good application to put it to use until a proper mass-produced molded piece is feasible/warranted
    • The BMS board not triggering a Red Triangle with a wire disconnected seems like a shockingly bad oversight, there's nothing stopping it from overcharging the cells with a broken wire. Even if they fix the whole cable routing and soldering issue by August (or later, Jack if you're reading this, there's nothing wrong with a product delay if it makes the end product better), if something were to happen during install or just over time through natural vibrations you get with a vehicle, you could/will end up with a failed cell scenario, which leads to unhappy customers or RMA, and RMA for the non-GT doesn't look like it'd be cheap for the company.
     
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  11. AzusaPrius

    AzusaPrius Senior Member

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    @TMR-JWAP
    Oh no here comes the main troll..
     
  12. AzusaPrius

    AzusaPrius Senior Member

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    @TMR-JWAP and all you do is ride the troll train kid, I have never seen a thread created by you with anything worth reading.

    All you do is troll other people threads and post your lame nice person comments and useless thoughts.

    But I guess every forum needs a troll like you to cheerlead other trolls.
     
  13. ChapmanF

    ChapmanF Senior Member

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    That wasn't my question, was it? If you're going to toss around the words slander and libel, that can't mean you "don't know" what he found. You'll have to be saying he didn't find what he says he found.

    Is that what you're saying?
     
  14. AzusaPrius

    AzusaPrius Senior Member

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    Look here chap he can say anything he wants right?

    It would he up to him paying a third party to evaluate his claims and prove them to be true and correct.

    All I know that is true and correct is that he is taking a product that is working and slandering and libeling the company that makes it.

    Its as if I were to buy a radio and I open it up for no reason, not because it does not work but because I want to and then I go about talking trash on it on how I think they should have used these batteries or resistors or wire gauge.

    That would just be my opinion and the damage of my opionion can be concidered slander or libel in a court of law.
     
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  15. BuckleSpring

    BuckleSpring Junior Member

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    This is good to do, fair, and even common. I frequently do this to (usually lower end) Chinese goods to find their weak points and correct them before an issue occurs. Stuff like poor solder joints, bad cable routing, using the wrong gauge of wire, etc.
     
  16. AzusaPrius

    AzusaPrius Senior Member

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    Until a company wants to sue you for your opinion that is causing harm to their business.
     
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  17. Tideland Prius

    Tideland Prius Moderator of the North
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    *Thread closed*

    Since the behaviour in this thread exhibited by some members are not in the spirit of PriusChat, I've closed this thread.
     
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