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Battery Experts Seek Lower Costs, Better Technology

Discussion in 'Prius, Hybrid, EV and Alt-Fuel News' started by bwilson4web, Apr 27, 2014.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I get a Ward's newsletter and it had this article about a Tokyo conference:
    Source: Battery Experts Seek Lower Costs, Better Technology | Asia Pacific content from WardsAuto

    On my recent 1,400 mile trip to pickup the airplane engine, I used the corporate cellphone to listen to podcasts and listen to our music collection on our older iPad. When I stopped outside of Cincinnati to figure out their by-pass, I took the Garmin in and ran it on battery while the iPhone was charged, waiting for dinner. These are the only LiON powered devices that provided significant value during the trip that was so practical because of our 2010 Prius using NiMH traction battery. In effect, we're in a transitional period of battery technology.

    So the article goes on to state:
    Source: ibid

    As LiON battery production capacity continues to increase, there will come a time when the battery supply train reaches excess capacity and 'the bidding wars' will start a sharp decline. A 'knee in the curve,' we will all benefit.

    Bob Wilson
     
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  2. bisco

    bisco cookie crumbler

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    there is still a disconnect in the business world. with all the communications devices we have today, companies insist on flying and driving people all over the world for sales meetings and such. personal relationships still work best, but it exacts a toll on the environment.
     
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  3. Former Member 68813

    Former Member 68813 Senior Member

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  4. austingreen

    austingreen Senior Member

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    As LiON battery production capacity continues to increase, there will come a time when the battery supply train reaches excess capacity and 'the bidding wars' will start a sharp decline. A 'knee in the curve,' we will all benefit.
    [/quote]


    I think we are already in the knee, and those forecasts were quite pessimistic. From your quote


    The DOE expects lower volume but a drop to $300/kwh or less by 2020. Tesla's megafactory definitely would have costs under $300/kwh and should be running long before 2020. Some are predicting $200/kwh. Note these are for batteries with cooling systems. A battery like the prius liftback without active cooling probably will be between $300-$400/kwh in 2010, but.... you require less kwh (although more control electronics) for usable state of charge and power than nimh. Probably 1 kwh lithium is the equivalent of a 1.3 kwh nimh in terms of performance of usable SOC and available power.
     
  5. movingforward

    movingforward Member

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  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    No.

    Bob Wilson
     
  7. Trollbait

    Trollbait It's a D&D thing

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    Capacitors can accept and release electricity quicker than a battery. In theory, it could 'boost' a hybrid if the motor is sized to take advantage of the higher rate of energy. It wouldn't be like a turbo. A turbo can boost as long as you willing to dump the fuel into the engine. The capacitor will quickly deplete, making such use more like a nitrous charge. Maybe the overboost function of some current, smaller engines is a better analogy. They can briefly increase max power output by around 20hp for something like a passing event. But parallel hybrids are already capable of this by combining ICE and motor plus battery output together. A capacitor could bring the motor up to speed quicker, but that rate increase will only be an actual advantage on a race track.

    The advantage of a capacitor for consumer vehicles is the reason Mazda uses one. They can capture more brake energy than the battery can. From there, the capacitor will charge the battery or provide some energy directly to accessories or the motor.
    MAZDA: Brake Energy Regeneration System | Environmental Technology
     
  8. movingforward

    movingforward Member

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    Last I checked, I think this current generation of the Prius' main electric motor still have 50hp of unused capability.

    If Toyota engineers incorporates a capacitor into the current synergy drive system, my guess would be that they can capture another 10% of efficiency in fuel economy and at the same time increase power output by almost 40% to 180hp with zero sacrifice whatsoever. Isn't Toyota running this setup (ultracapacitors) for their Le Mann's race car? Am I way off on this idea?
     
  9. Trollbait

    Trollbait It's a D&D thing

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    The LeMans car does use ultracaps, but no battery. I believe it has less total energy in them than the Prius in its battery. So it results in the SOC being quickly depleted beyond just what the high speeds would do. Other teams are just using batteries.
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Yes - I understand the Toyota racer uses ultracaps.

    Yes - you are way off about "50hp of unused capability." Here is my executive summary:

    There are MG1 and MG2 which are the two motors in the Prius. If you take the engine power times 28%, you get MG1 power. This happens to be the gear ratio of the Power Split Device, (PSD) that sends 72% of the engine power via the gears to the wheels while 28% takes the MG1 -> MG2 path. Engine power to the wheels requires 28% of it passing through MG1. Furthermore, MG2 is larger than MG1 by the capacity of the traction battery. Electric motors are terribly expensive because they use copper and very strong, rare-earth, magnet rotors. So both MG1 and MG2 are sized to match the engine capacity and no larger. For these reasons there is no "50hp of unused capability."

    Now if your goal is to make a "street racer" Prius, look at the solid rear axle. See if you can find a differential that will fit with a powerful, electric motor. Add an independent, motor controller and battery and you'll have the extra 50hp you want. There are 'wheel motors' but still experimental which means $$$ if you can buy one.

    Bob Wilson
     
  11. movingforward

    movingforward Member

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    ya right...anyway, according to Toyota engineers and the monthly magazine issues they send to owners the Atkinson cycle ICE produces 98hp and the electric motors are capable of producing 80hp. The 3rd gen Prius is rated at 134hp combined so where did the other 44hp go?
     
  12. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Ah, I see the problem. There are only two sources of power:
    • 98 hp - engine
    • (134-98 hp) 745 kw/hp = 26.8 kW the traction battery power
    The other "44hp" cycles in the transaxle:
    [​IMG]
    This recycled power (aka., "heretical mode") simply cycles inside the transaxle:
    • 98hp * 28% = 27 hp ## fraction that has to pass between MG1 and MG2
    • 2*27 hp = 54 hp ## never leaves the transaxle
    • 44hp / 54hp = 81% ## roughly the electrical loss of the MG1-MG2 path
    Understanding how the power flows inside the Prius transmission is not easy. But it really comes down to two power sources, ICE and traction battery. The additional motor capacity is required to transfer the 98 hp through the power split device (PSD) to the wheels.

    Bob Wilson
     
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  13. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I'll add more details to these charts later but you'll notice the traction battery, a limited power source (*), is not shown:
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]

    The traction battery power can be added but it is limited by the power controller and battery characteristics. Stuffing ultracaps in with the battery does not increase the power capacity of the water-cooled, inverter electronics. Fortunately, it protects itself from melting from an overload.

    If you want to make a Prius street racer, find a differential that will fit with an electric motor. Then replace the rear axle and add a power controller operated by the driver.

    GOOD LUCK!
    Bob Wilson

    * - At full power, the traction battery energy can be exhausted in about 2 minutes. Then the Prius reverts to ICE only power which is less than the "134hp." The Prius actually has two power values at the wheel:
    1. With traction battery energy, ~134hp
    2. Without traction battery energy because it has reach 40% state of charge (SOC), ~98hp minus losses
     
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  14. movingforward

    movingforward Member

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    I'm more interested in a super dino efficient car with AWD capabilities like a Subaru/Audi and I think Toyota engineers can achieve that feat with the extra power that's not tapped into in the electric motor. I know the battery will drain quickly when you floor it but with lithium batteries and an ultra-capacitor incorporated in the current HSD, I'm sure Toyota can make it happen! Now after reading that post you put up, Bob, thank you BTW, and if it is true that power is loss due to PSD then it is with great sadness to say that Prius' Achilles heel will prevent it from ever being THE awesome hybrid vehicle it could have been.
     
  15. GasperG

    GasperG Senior Member

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    Still the battery is limited to 26 kW, if you used supercap you could improve throttle response greatly with couple of ms with full 60 kW power (waiting for ICE to rev up). The other advantage is that you don't need to size supercap to 1.3 kWh but only to usable minimum of around 0.5 kWh or even less. You would need a bigger 12 V battery, for starting power for situations when you leave the car parked too long (a week?).

    Does anyone have the specs for Mazda i-eloop capacitor? What is the capacity and weight of that thing? Do we know what is the capacity and weight of Nishinbo supercap in TS040?
     
  16. telmo744

    telmo744 HSD fanatic

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    Switch to more energy deterioration when compressing/expanding...
     
  17. austingreen

    austingreen Senior Member

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    Probably the easiest thing to do is to start with a prius phv and add a mg3, perhaps the same as mg2 (80hp) but geared directly to give more torque at highway speeds and faster. Then the problems are getting more power and control. Toyota isn't giving up the control algorithm, so they have to do it, and electronic all wheel drive is rumored as an option in the next generation. That 4.4 kwh battery is probably good for anouther 30 kw (45hp) in 10 second bursts (it should be 38 kw and can probably give up anouther 19kw (half) in bursts for a total of 57kw) compared to the 1.4 kwh nimh (27kw), but panasonic only releases those specs to manufacturers. Add in wiring, controller, inverter, software, and you are good to go at around 180 hp electronic all wheel drive, with up to 80 hp on the rear axle. Give yourself a boost button to time the over power of the battery, when it cools you can boost again. If you want to go bigger electronic hp wise you can add the super caps and bigger motors, simply adding a super cap and its electronics + a mg3 sized like mg2 to the the nimh prius could boost you 80 more ponies.


    The power limitations are the battery and electronics, on the motor side, but quickly get to the psd for sustained hp. The psd needs to be built to handle the power of the ice and mg1.
     
  18. austingreen

    austingreen Senior Member

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    The supercap is 177kw. It should be at most 6MJ which is 1.7kwh, but likely much smaller and used multiple times in a lap. I don't see any size or weight specs for it.
     
  19. GasperG

    GasperG Senior Member

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    With around 6 heavy braking points in LeMans the capacity must be at least 1 MJ or 277 Wh and probably is around here somewhere.
    There are different kind of supercapacitors, one with high energy density and the one with high power density, just like there are different kind of batteries (Li-Air or A123).

    I was just wondering what actual products of supercap exists in reality?