Results 1 to 27 of 27

Thread: Tesla (the company) batteries

  1. #1
    Join Date
    Oct 2006
    Posts
    3,714

    Tesla (the company) batteries

    I keep reading about recent successes of not only Tesla cars but also other things powered by the kinds of batteries those cars have, including big rigs and power storage systems connected to power plants to essentially delay power delivery from when generation is at a highest to when demand is. But it wasn't very long ago that all indications were that battery technology just wasn't anywhere near being able to handle such things (because of things like vehicle range, recharging time, and power-to-weight ratio, and that's without even beginning to think about overall life span or environmental issues or mining of rare elements can run out of fairly quickly). Unless Tesla's achievements are being overstated, it seems that their battery technology must have suddenly gotten several times as good as it was before, within just a decade or two. How did that happen? What's so different about the batteries they're using now?

  2. #2
    Join Date
    Sep 2006
    Posts
    453
    Tesla is in cahoots with Panasonic on batteries. As far as I am aware they've had no significant break-through in the basic battery cell compared to anyone else. It seems that what they have done well is optimize combining large numbers of cells into large packs and management systems for the charging and discharging of the cells. That and production of battery packs. If you are not already familiar with it maybe google about the Tesla Gigafactory. It is a very large and innovative battery production facility that is a key component of Tesla's long term business plans.

    It seems likely that sometime fairly soon there will be a significant increase in energy capacity of lithium ion batteries, perhaps a doubling. There are several different concepts for improved anodes that reportedly could achieve such an increase and it seems plausible that at least one of them will pan out. It is possible that Tesla has such a new anode battery currently in the works, but they haven't announced anything like that.

  3. #3
    Join Date
    Jun 2004
    Location
    The Great NorthWet
    Posts
    13,089
    That's my understanding as well. Last year Santa gave me a rechargeable headlamp. It has a pair of 18650 size batteries. On looking that up, I was surprised to use that's what's used in Tesla cars. Just a few more of them.

    When Boeing was having trouble with the batteries on the 787 a few years back, Musk was quite critical of the supplier for making a custom monolithic battery instead of an assembly of small cells like Tesla.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  4. #4
    Join Date
    Sep 2006
    Posts
    453
    Yes. Though Tesla did fairly recently switch to a different size cell, 21 mm diameter x 70 mm long, designated 2170. The 2170 is reportedly being used in Powerwalls and the Model 3 while past and current Model S and X use the earlier 18650. There are rumors that they may start producing a bigger cell, 44 mm diameter x 160 mm long, the 44160.

  5. #5
    Join Date
    Apr 2005
    Posts
    2,218
    Quote Originally Posted by Delvo View Post
    I keep reading about recent successes of not only Tesla cars but also other things powered by the kinds of batteries those cars have, including big rigs and power storage systems connected to power plants to essentially delay power delivery from when generation is at a highest to when demand is. But it wasn't very long ago that all indications were that battery technology just wasn't anywhere near being able to handle such things (because of things like vehicle range, recharging time, and power-to-weight ratio, and that's without even beginning to think about overall life span or environmental issues or mining of rare elements can run out of fairly quickly). Unless Tesla's achievements are being overstated, it seems that their battery technology must have suddenly gotten several times as good as it was before, within just a decade or two. How did that happen? What's so different about the batteries they're using now?
    Li-Ion batteries are only a factor of 2 or so better in energy density than NiMH batteries.

    The 14500 Li-ion cell is the same physical size as an AA cell. I was a little surprised to see the volumetric energy density is about the same as well.

    I think Li-Ion win out because they can supply high peak power without damage and also no memory effect.

  6. #6
    Join Date
    Jan 2010
    Location
    Wisconsin USA
    Posts
    2,579
    Quote Originally Posted by kzb View Post
    Li-Ion batteries are only a factor of 2 or so better in energy density than NiMH batteries.

    The 14500 Li-ion cell is the same physical size as an AA cell. I was a little surprised to see the volumetric energy density is about the same as well.

    I think Li-Ion win out because they can supply high peak power without damage and also no memory effect.
    2 times by weight or volume?
    The moment an instant lasted forever, we were destined for the leading edge of eternity.

  7. #7
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    The electric airplane also uses loads of those small cells, no doubt to improve cooling. Those lithium cells can take a lot of current for clever fast charging but once charged they overheat unless you cut back. They will then if correctly charged gives many times more charge cycles than NiCd which develop internal crystals. It's the internal resistance factor. The problem with lithium is the call voltage does not change so clever chargers have to use in out memory and temperature sensing. In a large cell the core temp can rise and they don't like that! I imagine the in out memory method gets out of sync if the rate of charge /discharge varies because that messes up the internal resistance factor. Internal temperature sensors would be indicated but tricky for hundreds of small cells. Can you rely on a sampling approach? The Boeing experience suggests not. Just one overheating seems to go exothermic so damage spreads.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  8. #8
    Join Date
    Apr 2005
    Posts
    2,218
    Quote Originally Posted by Copernicus View Post
    2 times by weight or volume?
    Weight I would think.

    As I said, and you can check this yourself, a 14500 Li-Ion cell does not seem to have a better volumetric energy density than the same-size NiMH AA cell. The voltage is higher but the milliamps are lower.

  9. #9
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    did you see that Elan Musk just installed the world's largest battery in Australia? He said he would do it, (Tesla would do it) in 100 days or it would be free. It took 63 days (from memory). 129 MWh 100MW output. ...Well it impresses me, that's a lot of little grey cells.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  10. #10
    Join Date
    Jun 2007
    Posts
    264
    Tryed to hook up two power tool 18v li packs in parallel to cut discharge heating on a el lawnmower
    they just let the smoke out and died quickly

  11. #11
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Quote Originally Posted by nota View Post
    Tryed to hook up two power tool 18v li packs in parallel to cut discharge heating on a el lawnmower
    they just let the smoke out and died quickly
    you are literally playing with fire, the mower clearly has a much bigger motor and current drain. Your parallel probably left out the third wire connection too. What battery does the mower usually use, a 12v lead acid perhaps?
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  12. #12
    Join Date
    Jun 2007
    Posts
    264
    Quote Originally Posted by profloater View Post
    you are literally playing with fire, the mower clearly has a much bigger motor and current drain. Your parallel probably left out the third wire connection too. What battery does the mower usually use, a 12v lead acid perhaps?
    pair of motor cycle sized 12v lead/acid now dead original for 24v 20amps
    motor ran ok on 18v 4 amp li pack but discharge rate heated battery a lot
    I hoped to cut the discharge rate by using two units in parallel for a hoped for 1/2 amp share reduction and less heating

    it is a 18v + - connection what is the 3rd connection for ??
    what should the 3rd wire hook to and what does it do
    lawnmower only needs the plus/minus to work

  13. #13
    Join Date
    Jun 2004
    Location
    The Great NorthWet
    Posts
    13,089
    I've been wondering what the third connection on my tool batteries is for pretty much since I got them.
    Cum catapultae proscriptae erunt tum soli proscript catapultas habebunt.

  14. #14
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Quote Originally Posted by nota View Post
    pair of motor cycle sized 12v lead/acid now dead original for 24v 20amps
    motor ran ok on 18v 4 amp li pack but discharge rate heated battery a lot
    I hoped to cut the discharge rate by using two units in parallel for a hoped for 1/2 amp share reduction and less heating

    it is a 18v + - connection what is the 3rd connection for ??
    what should the 3rd wire hook to and what does it do
    lawnmower only needs the plus/minus to work
    The mower motor will run at 18/24 times the speed but the current will be nearly the same. Actually the nominal rating only reveals the motor resistance for first inrush current 1.2 ohms. The current once at speed depends on the load. The motor free running would take a small current once up to speed.

    Your lithium cells from a power tool are not used to that kind of current, especially for a long time, as in a mower. they can deliver 10 Amps, but for a short burst. They will get hot and catch fire if you persist.

    The third terminal gives the charger or the device a temperature value in order to protect the batteries. There will be no equivalent on the mower because they designed it to run on lead acid batteries and chose the right size. Those will also get hot on high current and they could fail too, but in general if the right size they will work on average grass cutting loads.

    Unfortunately if you investigate a proper Lithium battery to drive the mower, they do exist for electric scooters for example, the price will freak you out. the only economical batteries at this time will be lead acid and even those are expensive. Gel lead acid can be found online, they might be cheaper than going to a store.

    Are you sure about the volts, many motor cycle batteries are 6 volts? In which case your current on 18 volts would be even worse.

    You could investigate desulphating ideas for rescuing lead acid batteries, it involves short high voltage shocks which help restore the plates, and it does work if you have the time. There are self powered devices that use the battery itself to provide the shocks and with new batteries they do, in my experience, prolong lead acid life. Restoring old, apparently dead, lead acid is more hit and miss.

    I really would stick to lead acid for your mower project, sorry to disappoint.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  15. #15
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Quote Originally Posted by Trebuchet View Post
    I've been wondering what the third connection on my tool batteries is for pretty much since I got them.
    As noted to nota, all lithium batteries have thermal sensors and they help keep them safe in both charge and discharge. Generally it seems to work well. Otherwise Lithium really does catch fire even in clever systems like Boeing must have had. I have had a Lithium drill with battery in the handle for many years now, i've had to fix the charging contacts a few times, but the duration of charge and power seem as good as ever. I'm a fan.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  16. #16
    Join Date
    Sep 2006
    Posts
    453
    My kids recently acquired a 56 volt lithium ion battery powered electric blower for a hover-craft project. This is a consumer product available at Home Depot in the US, and various places via the internet. It can put out 600 CFM. The battery is 5Ah. I believe they make a 7.5Ah battery that can be bought separately as well. The same company makes electric mowers that use the same battery. So, Lithium-ion batteries seem well capable of powering the mower, but finding a battery with the output properties you need for your particular mower is not likely.

    Given that the tool and the battery need to communicate temperature data for safe operation, and that in your case of trying to jury rig Lithium-ion batteries to power a tool not designed for that, it doesn't sound like a good idea. In any case, it isn't something you are going to be able to do on the cheap.

  17. #17
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Quote Originally Posted by Darrell View Post
    My kids recently acquired a 56 volt lithium ion battery powered electric blower for a hover-craft project. This is a consumer product available at Home Depot in the US, and various places via the internet. It can put out 600 CFM. The battery is 5Ah. I believe they make a 7.5Ah battery that can be bought separately as well. The same company makes electric mowers that use the same battery. So, Lithium-ion batteries seem well capable of powering the mower, but finding a battery with the output properties you need for your particular mower is not likely.

    Given that the tool and the battery need to communicate temperature data for safe operation, and that in your case of trying to jury rig Lithium-ion batteries to power a tool not designed for that, it doesn't sound like a good idea. In any case, it isn't something you are going to be able to do on the cheap.
    Note that a 56 v battery at say 5 amps is already 280 watts. And it will be protected by a third terminal.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  18. #18
    Join Date
    Aug 2013
    Posts
    324
    Quote Originally Posted by Trebuchet View Post
    I've been wondering what the third connection on my tool batteries is for pretty much since I got them.
    If it's a white connector it is probably for balancing the individual cells within the battery if you use a balancing charger.



    The only real downside for the battery farm is that, depending on how often they are used, the individual batteries have to be replaced every 10 to 20 years so the mega battery requires continual maintenance and is not a set and forget installation.

  19. #19
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    I still think its the thermistor terminal. Battery balancing is done in the factory for Lithium but because of the constant cell potential it's difficult to do in the field. The electrons in and out pass through all the series cells, and parallel connections have to be separately charged. Ie a nearly flat cell and a fully charged cell show the same voltage and internal resistance. That's a good thing for your power tool, it works until it stops. It's a problem for a charger but generally you assume the cells are all the same as produced in the factory, so in series there is no balancing required. The temperature is monitored for safety and long life.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  20. #20
    Join Date
    Jun 2007
    Posts
    264
    Quote Originally Posted by profloater View Post
    The mower motor will run at 18/24 times the speed but the current will be nearly the same. Actually the nominal rating only reveals the motor resistance for first inrush current 1.2 ohms. The current once at speed depends on the load. The motor free running would take a small current once up to speed.

    Your lithium cells from a power tool are not used to that kind of current, especially for a long time, as in a mower. they can deliver 10 Amps, but for a short burst. They will get hot and catch fire if you persist.

    The third terminal gives the charger or the device a temperature value in order to protect the batteries. There will be no equivalent on the mower because they designed it to run on lead acid batteries and chose the right size. Those will also get hot on high current and they could fail too, but in general if the right size they will work on average grass cutting loads.

    Unfortunately if you investigate a proper Lithium battery to drive the mower, they do exist for electric scooters for example, the price will freak you out. the only economical batteries at this time will be lead acid and even those are expensive. Gel lead acid can be found online, they might be cheaper than going to a store.

    Are you sure about the volts, many motor cycle batteries are 6 volts? In which case your current on 18 volts would be even worse.

    You could investigate desulphating ideas for rescuing lead acid batteries, it involves short high voltage shocks which help restore the plates, and it does work if you have the time. There are self powered devices that use the battery itself to provide the shocks and with new batteries they do, in my experience, prolong lead acid life. Restoring old, apparently dead, lead acid is more hit and miss.

    I really would stick to lead acid for your mower project, sorry to disappoint.
    had the li batterys on hand for power tools
    they are 18v normal 20v peak at full charge 4 amps each drop to about 16v at near full discharge auto shutoff
    two 12v lead/acid originals for 24v rated 20 amps BUT lead/acid will not live if full discharged so 10 working amps if expected to live long
    vs 2 18v li at 4amps each that will almost fully discharge for 8 amps work done vs 10amp l/a real useful power

    have a desulphating charger for 12v car batterys
    tryed it on the mower l/a battery stone dead from over discharged use with no good results

  21. #21
    Join Date
    Jun 2007
    Posts
    264
    really do not like sealed l/a battery in the tropic's gel or not they lose water over time do to charging or evap
    and that water can't be replaced in a gel cell or mat ether

    I have cut open a regular sealed liquid l/a battery to add needed water to get a few more months use more then once
    can't do that to a gel or mat unit
    and both mat or gel die quickly if over discharged even a few times

  22. #22
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Quote Originally Posted by nota View Post
    really do not like sealed l/a battery in the tropic's gel or not they lose water over time do to charging or evap
    and that water can't be replaced in a gel cell or mat ether

    I have cut open a regular sealed liquid l/a battery to add needed water to get a few more months use more then once
    can't do that to a gel or mat unit
    and both mat or gel die quickly if over discharged even a few times
    I guess you are tough on your batteries, taking them outside their comfort zone. You are right that lead acid do not like complete discharge but it's recommended to use cell voltage to determine when to stop. Lithium does allow near complete discharge but you should still stop when the volts drop. Lithium devices do that but rigging to your motor risks overheating and complete discharge as you found. If a gel type is out gassing it is working too hard, you need to use a bigger size. I have over used them and they swell quite alarmingly. But used within their limits they last five years. I know it's frustrating but a correctly sized battery gives better service. A push mower counts as good exercise too!
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  23. #23
    Join Date
    Oct 2006
    Posts
    3,714
    Quote Originally Posted by Darrell View Post
    It seems that what they have done well is optimize combining large numbers of cells into large packs and management systems for the charging and discharging of the cells.
    I just ran into some other battery-related news that makes this all sound very bad. The thing about Apple slowing down phones that are a few years old is apparently meant to preserve diminishing battery power. But if it's fundamentally the same stuff, and that stuff wears out that significantly in such a short time, then Tesla is building cars and even power-plant load-smoothing systems that will all be dead spectacularly quickly!

  24. #24
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    Just like lead acid, the key issue is whether recycling works. With lead it works pretty well. It's part of the total cost of the system.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  25. #25
    Join Date
    Feb 2011
    Posts
    378
    Tesla recently used Samsung batteries in the Australia battery project, which AIUI use a more advanced chemistry.

  26. #26
    Join Date
    Apr 2011
    Location
    Norfolk UK and some of me is in Northern France
    Posts
    7,546
    I believe the cylindrical type of cell is cheaper than the flat type used in mobile phones, although the energy density of the latter is higher, the life is also shorter. The so called polymer type use microporous separators but there is still a wet electrolyte inside. The development is no doubt in the details of production, quality and consistency. Those will be guarded secrets that make all the difference in the end.
    sicut vis videre esto
    When we realize that patterns don't exist in the universe, they are a template that we hold to the universe to make sense of it, it all makes a lot more sense.
    Originally Posted by Ken G

  27. #27
    Join Date
    Mar 2003
    Posts
    542
    I'm a big fan of Li ion batts, I fitted a set to the Amarouke about 6 months ago for camping and running the fridge, lights etc. 60Ahr (4x3v cells in series) replaced 2x 120Ahr deepcycle LA's, last longer by about a third, totally maintenance free, last at least three times as long if not considerably more (10-20 years against 3-5 yrs) and a major weight reduction (7kg against about 30kg)

    They do require a balancer- but again its a fit and forget module, and I got a nice little monitor that checks all the bats individually and as a group, has programmable audible alarms and cuts the batts off if anything goes wrong or if they are discharged

    The same company I bought mine off make a huge range- their biggest is a monster 10000Ahr cell.
    IMHO, lead acid is deader than the dodo, and good riddance

    Considering the amount of kit I bought, it was remarkably cheap to replace the twin deep cycles with these batts- replacement deepcycles were going to cost around $580, the lions ended up a tad over $800, so not that much more for a huge performance and lifespan increase

    in the pics, you can see the balancer just to the left of the batts. fuses go to the monitor for safety (as each wire goes straight to a battery terminal so dont want any possible shorts, unlike LA batts these babys deliver BIG current!) and the monitor just above the fridges plug- used 5 core trailer cable as the monitor leads. One thing about these batts is they have to be under compression, hence the heavy aluminium box with bolts for that, also helps with heat dissipation as a big heatsink
    Attached Images Attached Images
    R.I.P. Bad Astronomy

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •