TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

Battery development rate

Discussion in 'Electric Vehicles' started by Realistic EV Fan, Aug 14, 2014.

  1. Realistic EV Fan

    Joined:
    Aug 14, 2014
    Messages:
    13
    Location:
    Edmonton
    I wonder what is the battery performance increase rate from development. Currently some already stated that batteries improve at a rate of about 7 to 8% a year. I am very much beyond skeptical about the fact. Already there are signs that the next-generation battery for the model three will be about 10 to 15% better. Realistically the biggest determining factor in battery performance is the chemistry and that is not increasing at a very fast rate at all. It is not like electronics or software, chemistry development is in fact slow and painstaking. Both the research is slow and then even testing the battery takes even more time just to find out that it doesn't perform on one of the tests. There are roughly about five categories to which a battery has to perform, not just energy capacity per weight.


    • But we must provide good energy capacity per mass and volume. While lithium air batteries can increase today's batteries capacity per weight by 15 fold, their lifespan of about eight cycles of charge and discharge makes them currently quite useless.


    • An automobile battery must also be powerful and have a high rate of charge and discharge. Super capacitors are amazing at extremely quick charge and discharge but fail miserably in terms of actually storing a lot of energy.


    • An automobile battery must be cheap to produce. Replacing expensive and toxic metals with anodes and cathodes made from sulfur and silicone can make battery production a lot cheaper. But their limitation in durability currently makes them not so good for automotive use.


    • The battery must be able to deal with extreme temperature changes. The temperature management system definitely can help when the vehicle is traveling. But even the storing of battery in a very hot climate inside the vehicle that with all of the class outside greenhouse effect can greatly reduce the lifespan of the battery. Using the battery in extreme cold, before the battery warms up, and for example make lithium ion batteries reduction in life and performance. It seems that the worse the chemistry in terms of performance like lead acid or nickel cadmium, the better they are at handling wild swings in temperature.


    • The biggest cost factor in owning an electric vehicle is the replacement cost of the battery. Durability of a battery is therefore paramount. Already solid-state batteries have the advantage of up to 10 full durability compared to today's liquid electrolyte lithium-ion batteries. But their low power limits their charging and discharging rates to below what is acceptable for an electric vehicle. Even storing the battery at high temperature can greatly reduce its life. Side reactions usually increase with temperature in the side reactions are usually nonreversible and slowly chewing up the reactants inside the battery wearing it out. There's also corrosion increasing with temperature which also shortens the life of the battery with age at higher temperature.

    Since the new battery must be able to perform well in all five categories it is hard to find chemistry that does just that and so realistically it seems to be safe and conservative estimate than battery improvement is roughly about 2% a year. The model three will be released in 2017 and I likely have a 10 to 15% improvement in battery over the 2012 Model S. I calculated the improvement from a number of years between car development and the percent increase in battery density per mass. The more optimistic look yields about 3% improvement a year.

    I'm curious to what most people think the battery development rate is? There's a lot of optimistic exaggeration but if you look down on what has actually been released in what type of time frame than one can see future electric vehicles to have similar performance to today's in the next five years. Yes 10 to 15% improvement is actually fairly noticeable for the average commute, but it's not going to change how one drives the EV in terms of planning and range of use.
     
  2. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    Elon and JB Straubel say 7-8% per year. So I think it's 7-8% per year. Your analyzis is otherwise very much correct.
     
  3. Realistic EV Fan

    Joined:
    Aug 14, 2014
    Messages:
    13
    Location:
    Edmonton
    But Elon contradicts this.

    Even Elon contradicts himself stating Model III Battery will be 10 to 15% better. With four years in development that should be a conservative 28%+.:confused: Obviuosly development is not perfectly linear, but it seems on track for 20 to 30 % increase in energy density in the next 8 to 1- years. So next gen Model s should have 100 to 110 kWh Battery. Hopefully cost comes down a lot faster then that as it is critical right now for affordabilty vs ICE.
     
  4. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    Who knows what is meant by "better"? That battery in Gen 3 will be in another format, price range. Cell wise it's gonna be 7% per year on average, with some step changes in the curve. The "battery" as you say i.e. the battery pack is more than the cells. If you were to keep the exact same form factor with the S/X I bet in y number of years as compared to 2012 you could make a battery pack with 1.07^y times more capacity at roughly the same price. However, with the Model 3 they are probably going for somewhat smaller packs and a much lower selling price - the actual cost to Tesla is not known to us. Also don't equate neither cost nor selling price with "rate of improvement" since you have economics of scale (Gigafactory) etc. that lowers price regardless of technical/chemical improvements, but those two processes happen in parallel.
     
  5. Matias

    Matias Active Member

    Joined:
    Apr 2, 2014
    Messages:
    1,590
    Location:
    Finland
    Here's direct quote from Q2 2014 conference call

    "Colin Langan – UBS


    And on the Giga Factory, I mean is the chemistry going to be the same battery chemistry that you're currently using or is that part of the discussions that are going on with Panasonic?


    Elon Musk


    There are improvements to the chemistry, as well as improvements to the [indiscernible]. So we would expect to see an energy density improvement, and of course a significant cost improvement.


    JB, do you want to [indiscernible]?


    JB Straubel


    Yeah, that's, you know, the cathode and anode materials themselves are next generation, so we're -- I mean we're seeing improvements in the maybe 10% to 15% range on the chemistry itself.


    Elon Musk


    Yeah, in terms of energy density."

    - - - Updated - - -

    So they say in Gigafactory cells energy dencity will be 10-15% better than now. Tesla has used same energy dencity cells from 2012 and Gigafactory will be online maybe 2017. So in five years 10-15% improvement. This is obviously much less than 7-8 %/ year.
     
  6. Grendal

    Grendal Active Member

    Joined:
    Jan 31, 2012
    Messages:
    2,521
    Location:
    Santa Fe, New Mexico
    The sixth factor is cost. If calculate the reduction in cost into the equation then you have your 7% per year. Because mathematically if you calculate the energy density gain and cost factor drop you can easily see the 28% improvement that you are talking about. It might even be more than that with the gigafactory price reduction thrown in.
     
  7. Realistic EV Fan

    Joined:
    Aug 14, 2014
    Messages:
    13
    Location:
    Edmonton
    Definittion of better battery

    I guess everybody has a different definition of better. To me a better battery is lower cost, higher capacity and longer durability keeping all else the same compared to today's lithium-ion battery.
    The key ingredient to electric cars is the battery, technology is the only thing that can both reduce the cost and weight as well as extend durability for the life of the car which is usually considered to be 15 years.
    Unfortunately improving technology is a lot harder than it looks. It's an endless process of trial and error to get something actually better. Innovation is frustration of taking an educated stab at a new idea and then constantly being disappointed and hoping eventually actually something better to comes out.
    Economy of scale can provide some cost relief, but economy of scale do not reduce the cost of raw materials needed. Economy of scale cannot extend the life of the battery for the entire life of the car which is also critical for the adoption of the electric vehicle. Sure one can change the battery, but the cost of the new battery becomes proportionately high compared to the entire value of a 10-year-old vehicle.
    Technology has to solve the remaining obstacles and electric vehicles.


    • Extend the life of the battery for the entire life of the car which plays heavily into the overall cost of the vehicle over its lifetime.


    • Further reduce battery cost and weight so as to increase range of affordable electric vehicles to a minimum of 400 km or 250 miles being probably the ideal as vehicle range degrades with low temperatures in northern climates as well as due to degradation of the battery. Also the actual range is probably going to be less than 250 km or 160 miles a day as to extend battery life most people can not charge to full capacity on an everyday basis.


    Charging speed is always going to be against electric vehicles. But personally I don't think the speed of recharging is a critical flaw. It's something that can be lived with and people can adapt to it. It's rare for somebody to need more than 250 km of actual range in a day.
     
  8. abasile

    abasile Independent Software Eng.

    Joined:
    Oct 21, 2012
    Messages:
    362
    Location:
    San Bernardino Mts., CA (Elev. 6100' / 1800m)
    I think it can be well argued that today's battery Li-ion longevity, weight, power, and energy density are already "good enough" for the mass market. Tesla battery packs seem to be retaining their capacity well enough, and vehicle weight is a challenge but by no means a showstopper.

    The primary area in which improvements are needed, to reach the mass market, is cost. If price/performance improves by 7-8% per year, then I think we are on the right track.
     

Share This Page