Batteries and New Battery Technologies

Discussion in 'Boat Design' started by brian eiland, Mar 28, 2008.

  1. BertKu
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    BertKu Senior Member

    Phil, Can we philosophy for a recharging station of the future, for boats and cars. We have a field with solar panels good for 2000 m2 @ 6 hours sun energy of 200 watt per square meter will give us 2400 Kwh over and above some windmills providing a couple of hundred Kwh during the night and day. This stored in 20 charging connection points, which each has super capacitors holding the possibility for fast discharging into a 5 minutes 400 or 800 Volt battery pack. Such charging point should have a bright green light indicating that it is ready for discharge and a bright red light for indicating to the motorboat or car driver to skip as the charging point is not yet ready fully charged and ready to give energy to the user.

    I see the following problems.
    a) Will the automotive industry ever standardise on the Voltage used for cars and the motorboat industry standardised for boats. So far OceanVolt is 48 Volt and Torqeedo is 24 Volt and 345 Volt. The car/boat user has to do some very good thinking before he can re-charge his battery. Will the "pump" has a voltage selector on their system? 12, 24, 48, 345, 400, 800 Volt? or will the unit be automatic sensing the voltage required?
    b) will 20 charging points be good enough per charging point, should it not be 100 or more ?
    c) How would we pay per minute charging or do we have a kwh/money meter clocking the energy pumped into the battery.
    Volkswagen is gearing up for full production of electric cars for 2020 so does Mercedes and Audi and many other car manufacturers.
    d) will there soon be more electric dives manufactures for motorboats popping up in the world or will it stay with Torqeedo and OceanVolt.
    e) how does Tesla charge their customers with their re-charging stations.

    What are you views.
    Bert
     
  2. portacruise
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    portacruise Senior Member

    There is no infrastructure or capacity to sustain 5 or 17 minute charging comparable to a petrol station- AFAIK. It would take very special planning to not quickly run out of electric fuel at the fuel station because of the slow recharge rate of the bank at electric refuel station. Supercaps don't get around the huge conductor needed whether in parallel or not, if a hard connection is used for charging. If inductive charging is used, a massive coil of huge conductor cable as described above might have to be on the EV itself. The range of EVs is given for average to optimum conditions and can easily vary by 50%+ (due to Peukert equation, age of battery, temperature, unmatched cells, etc.). Li battery systems are easily damaged by heat, overcharge or overdischarge, so the battery electronics shut things down before the defined limits making it appear that one has used 100% the charge contained in each cell. For any battery chemistry, individual cells cannot be matched exactly, so some harmful cell reversal is bound to occur each time if any battery is run to zero- drastically shortening the battery life.

    Hope this helps.

    PC
     
  3. philSweet
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    philSweet Senior Member

    120 kWh x 20% = 24kWh in 4 minutes. 120kWh x 80% = 96kWh in 17 minutes. That's a 360kW and 340kW average, respectively. My house service connection is the standard 50kW (200A 120/240V) used in the US. And residential meters aren't continuous rated (you can get "transformer duty" panels and meters that are). Even a light industrial meter is 100kW (400A 240V). If you go to 3 phase, where available, you can get up to 800A wye 120/208V service. That's 288kW. Getting there. But if you want 360kW, you will need 3 phase wye 277/480V 800A service or 3 phase delta 480V 400A service. So this is for service station equipment, not for the home. 360kW/800V is 450 Amps. That's still a whole heap, and I'm not sure self service would be a good idea. Things can go bad VERY QUICKLY with these sort of power flows. I was standing in a new generator shack when one phase of a 700V service bolted itself to the back of one of the switchgear panel's mounting studs. I had the panel doors open. Half the stud turned to plasma and the other half shot between my knees and then through a solid poured block wall and kept going. That was before the 1200A main breaker decided to trip. The fun part was the exit door was at the opposite end of the shack and there was only about 6" of space between the wall and the running C-175-16. I came out with torn pants, ringing ears, clothes smoking from head to foot and some minor flash burns, but generally unharmed.

    But it does appear there is going to be a need for high-power-rated umbilical connectors in the near future - ones that are safe in a rich hydrocarbon environment.
     
    Last edited: May 21, 2017
  4. BertKu
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    BertKu Senior Member

    Thanks for your thoughts and sorry to learn that you also had an encounter with high currents/voltage incident. You are lucky to survive with so little damage. I see it all different. A house connection, means that the person normally has the time for recharging over 8 to 10 hours period. Immediately it changes the situation. I still think my idea from 40 years ago and today's system from Tesla, to have a 100 m2 solar panel system on most of the roofs of houses. Then fast charging of high currents could be possible. However like you said, it could be tricky for a lot of people and housewife's. Solar on all roofs, maybe not for northern Europe, but the Southern part, they have enough sunshine. Mercedes Benz also is trying to get a slice of the American market. Most likely an extra set of batteries for long distance trips could be a solution. But what about for boats. There is no standard, like I have said in a previous thread. If everybody is having a standard battery pack, a lot of problems could be made easy. I wonder what Volkswagen/Audi/BMW/Mercedes Benz has in mind for 2020 and whether those battery packs could be used for boats.
     
  5. BertKu
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    BertKu Senior Member

    Hi Porta, thanks for your thoughts. I am inclined to think different in the sense, that somehow the industry will come up with solutions and new systems. A solution is like we have it here for the 9 Kg gas cylinders. The 9 Kg gas cylinders stays the property of the gas supplier and it get exchanged. Like we could do it for battery packs. Let see what Volkswagen and the other German manufacturers are bringing onto the market in 2020. I hope I can use them for the boat. I still think that a electric fuel station of the future may supply fast exchanging of battery packs as a solution. (for a fat fee most likely). Bert
     
  6. portacruise
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    portacruise Senior Member

    Phil, your calculation seems to show 3 phase would work, at least for one car recharge at a time- but that may mean a waiting line. Do you think it would help if these are set up near trunk lines, which might allow for more stations at the same place? That plasma incident associated with hard wiring is scary, do you think induction charging would help in the vehicle case, and is it practical over a 17 minute recharge period?

    Hi, Bert. There are a lot of challenges other than standardizing (it has been tried in Israel and Denmark) with using massive battery paks- compared to 9 Kg cylinders: Standardized Electric-Car Battery Swapping Won't Happen: Here's Why http://www.greencarreports.com/news/1090933_standardized-electric-car-battery-swapping-wont-happen-heres-why

    Also this on the Tesla quick change system: Musk: Tesla "unlikely" to pursue battery swapping stations http://www.roadandtrack.com/new-cars/car-technology/news/a25872/elon-musk-tesla-battery-swap/
    Electric boat battery swapping might be an even greater challenge because of the low center of gravity preferred for the heavy battery pak.

    But who knows, some new technology may change things in the future (superconductivity breakthroughs, etc.). Induction charging might be able to circumvent the different voltage issues which you referred to above by using different coils windings on the vehicle itself.

    PC
     
  7. BertKu
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    BertKu Senior Member

    Thanks Porta, I personally think that the industry has to come up with some form of standardisation on the battery packs to make the electric cars and boats a success. It will be an impossible task to have in all cites and villages refuelling systems for all kind of batteries and battery packs. The same applies for boats. I am not worried about centre of gravity, in view that a Lithium boat battery is only low weight comparable to SLABS and other heavy batteries. Lets philosophy. Here one has an electric boat and likes to sail from Cape Town to Durban. No problem to stop at various towns and cities. But he has now to worry where do to get the same connector and the do they have the same battery to swap or recharge. What will happen, nobody will then travel with an electric boat.. Bert
     
  8. Jim Caldwell
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    Jim Caldwell Senior Member

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  9. BertKu
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    BertKu Senior Member

    Thanks Jim, indeed the right way to travel around the world. In their case they were clever and had sails added to their package. Interesting to note that they were also clever to have a South African made catamaran. Good value for money. However I was more looking at the normal electric motorboats without sails. I doubt it that they will do the same from Cape Town to Durban without having to mount their sails. What it indeed means , we cannot do it without sails. I love their Lithium battery packs. Jim thanks for that link to those interesting couple and their experience. Bert
     
  10. kerosene
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    kerosene Senior Member

    L7 drive claims a smart voltage shift system allowing low voltage packs. Essentially on massive cell or parallel connected essentially rendering need for BMS obsolete.
    Same system would make input of variable voltage DC (wind or solar) straightforward.

    It is a startup and I am slightly skeptical until we see more details.

    Technology | L7 Drive http://l7drive.eu/technology/
     
  11. kerosene
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    kerosene Senior Member

    • No need for BMS
    • Full capacity is always usable, one weak cell does not stop the vehicle
    • One device takes care of both cell management and motor control
    • Full regenerative braking capabilities
    • Maximum power available independent of the motor speed
    • Can directly charge the battery from unstable voltage sources, like solar panels
    • Only requires a simple isolated AC-DC converter for charging, intelligence is in the Drive
    • Intelligent solution suitable for all Li-ion chemistries
    • Fully scalable from 250W to 40kW and beyond.
     
  12. portacruise
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    portacruise Senior Member


    Interesting, but it is a battery management system (with more functions built in?) as the single/parallel cell cannot be allowed to go anywhere near zero or above maximum charging voltage (esp. for lithium). Also no mention of the electronic losses of L7 from the various aspects that it performs. Upconverters tend to be more lossy than downconverters as I recall. No evidence of a working product, and the basic concept has been around for quite awhile.

    PC
     
  13. kerosene
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    kerosene Senior Member

    Indeed. The cell voltage management seems doable but the other questions are same as mine. Is there really unique innovation or is it just old stuff in a new wrapping.
     
    Last edited: Oct 9, 2017
  14. kerosene
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    kerosene Senior Member

    "L7 Drive esittelee seitsemän vuotta Suomessa kehittämänsä teknologiansa ja ensimmäiset tuotteensa ensi viikolla Saksan Stuttgartissa isoilla sähköautojen, akkujen ja komponenttien EVS30-messuilla"

    "L7 Drive presents seven years in Finland in development technology, and the first products next week in Stuttgart, Germany, fair of electric vehicles, batteries and components -EVS30 Fair."
    (Quickly stitched google translation)

    Read elsewhere that the 1st product is a 1.7kw (kWh?) setup fo mopeds and alike.
     

  15. BertKu
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    BertKu Senior Member

    very interesting and we will be looking forward to the reports from the fair in Stuttgart. Bert
     
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