Published on July 16th, 2016 | by Zachary Shahan


BMW+Samsung Batteries vs Tesla+Panasonic Batteries — Which Are Better?

July 16th, 2016 by  

It’s a question central to electric vehicle (EV) leadership: Who’s leading on the battery front? We’ll leave GM & LG Chem out of it for the time being, but a recent comment (+ referenced article) here on CleanTechnica brought up the question of BMW+Samsung batteries vs Tesla+Panasonic batteries, and it seemed worth discussing.

Unfortunately, we don’t have enough data to do a complete comparison of the different battery cells and battery packs used in Teslas vs the BMW i3, but I think we have some good guidance.

Price/kWh Is Critical*

The single most important component of an EV for cost-competitiveness is the cost+number of its batteries. If the carmaker has access to low-cost batteries, it can produce a car that is superficially competitive with gasoline cars in terms of the balance between upfront price and features/size, while also providing long enough range that it is acceptable for a normal consumer. (Naturally, if consumers are aware of all of the “deeper” benefits of EVs, a gasoline car can seldom compete with an EV, but consumers by and large are not aware of these benefits, so it’s generally a moot point.)

For years now, the research we’ve seen has put Tesla at the top of the list for the cost/kWh of its batteries (though, it was close to Nissan according to one estimate a couple of years ago). The most recent statements from Tesla put its battery pack costs below a surprisingly low $190/kWh — though, that’s also approximately what an estimated GM/LG Chem battery pack costs for the upcoming Chevy Bolt (based on GM’s announcement of $145/kWh LG Chem battery cells and an extra 30% estimate for the remaining pack costs, which brings a pack to $189/kWh).

Since Tesla and LG Chem are the only ones to have announced long-range electric cars for under $40,000, they’re the only ones we can solidly presume have contracts for batteries at a low enough cost to offer such cars. However, there’s plenty of hope that BMW and Nissan are coming to that point as well — but that they don’t want to undercut their current offerings by making their plans public.

For the moment, though, simply put: You can buy a large, fully electric, premium-class sedan with >200 miles of range from Tesla for $66,000 before incentives, and BMW’s subcompact (yep, subcompact) i3 costs $51,400 with under 100 miles of range. There are other factors at play as well — the i3 is made of rather expensive carbon fiber, for example, and the Model S comes with Supercharging — but it seems like a safe conclusion that BMW’s batteries are much more expensive than Tesla’s.

Price/kWh Isn’t Everything

Whether things or not are as we presume in the $/kWh side of the equation, it’s important to realize that kWh is only about initial rated capacity and doesn’t cover the full story.

Battery expert Denis Rakcheev, Founder and CEO of Versatile Energy Provider, recommended adding power density (kWh/kg) as a key parameter to consider. He summarizes:

Tesla modules are relatively cheap (one could find even cheaper lithium-chemistry batteries, but power and thermal performances of those batteries would not be great). However, Tesla’s cells are one of the most gravimetrically efficient.

The more the vehicle weighs, the more energy it will require to propel itself. Different manufactures took different approach to address this. Tesla went for a diplomatic approach: aluminum body and high-energy-density cells (140 Wh/kg, similar to the Nissan Leaf battery). BMW i3 has one of the lightest bodies, made of carbon fiber, but rather-low-density cells (95 Wh/kg), while Kia Soul EV has an ‘old school’ heavy steel frame but extremely dense lithium-polymer cells (200 Wh/kg). Thus, ideally for the customer would be a vehicle with all these advantages, maybe Faraday Future? 

(Just to give a small insight on small players and startups: in our project, VEP-Tech, we use cells with 112 Wh/kg and 210 €/kWh. From Samsung SDI, by the way.)

Aside from power density, and also aside from but related to price per kWh of initial capacity, if batteries could only be cycled (fully discharged and charged) 10 times before losing 20% of their capacity, they’d be big losers and the car companies and models using them would be in the junkyard.

This is where the reader comment noted at the top of the article and the comparison between BMW+Samsung batteries and Tesla+Panasonic batteries come in.

Long-Term Planning … It’s A Skill

Tesla+Panasonic batteries, it should be noted, have held up very well so far.

tesla battery degradation

Also, remember that Tesla provides an 8-year and “infinite mile” warranty on its batteries.

Still, that doesn’t mean Tesla has the “best” EV batteries on the market.

Tesla Motors battery cellThe article recently linked by commenter Jenny Sommer was a 2013 interview with Sven Bauer, the CEO of BMZ, which at the time was Europe’s largest battery manufacturer (and perhaps still is, but I’m not seeing current data on this). Interestingly, he said “the battery life is not very long” for the 18650 batteries Tesla uses in its cars. He added that, “the cells in the BMW i3 are state of the art.” He said they are designed to last for 20 years.

First of all, I’m not sure how much he actually knew about Tesla’s batteries, since he indicated the battery cells were the same as those in laptops, but we know that Tesla’s battery cells are actually quite different from those, and Elon, JB, and team didn’t see conventional 18650 battery cells as adequate for cars either. But moving on from that….

The question is: Will Tesla’s batteries not be great for cars after 8 years? Will they last well enough to 20 years? Will BMW’s batteries really go to 20 years without losing comparable range? (Again, let’s also ignore how many batteries the BMW i3 has, even thought that’s important for the usability of the car, just to focus on the battery qualities themselves.)

BMW i3 battery cells

BMW i3 battery cells.

These are questions none of us know definitively, but Sven seemed confident in his opinion. Asked how reliable the 20-year service life estimate for the BMW i3’s batteries is, Sven said, “It is very reliable. It is possible to prove this within exactly a month. Putting it precisely, the battery life is 20.9 years. End of life means that the battery can still be charged up to 80 percent of its original capacity.”

Again, after bouncing these comments off of Denis Rakcheev, he added more context:

Here there is an important aspect that was not touched by Mr. Sven Bauer. This is the design of the electrodes. High values of the energy density are defined by the specific area onto which lithium ions can get adsorbed. This specific area can be manipulated by, for example, adding more layers of the electrode material and/or by increasing the porosity of the electrode surface by arranging nanowire structures. Increasing the electrode-specific surface is an expensive process, that requires careful testing to ensure thermal stability and power characteristics of the cells. As a result, one gets a golden middle between energy density and power density. BMW took a cheaper way by using less-energy-dense cells. That’s why I think this comparison of ‘Goliath vs Achilles. Who’s weakness is bigger?’ starts to take shape when major details of the battery cells are compared. 

Sven Bauer noted back in the 2013 interview that there was a price tradeoff for these longer-life batteries. He didn’t put out a price, but said that BMW’s battery cells cost more than Teslas. He stated:

“Large-volume cells with 20 years’ service life such as those in the BMW i3 offer significantly higher performance, but are currently more expensive in terms of watt-hours. Significantly less effort is required, however, for the battery management. We are now also talking about prices between 250 and 300 euros per kilowatt-hour, but for considerably higher performance and a longer life.” (Remember that this interview took place in 2013, so prices aurely are quite different today.)

In response to another question, Sven said, “Tesla has a battery that works. But in comparison with this, the battery in the BMW i3 is a quantum leap.”

Denis Rakcheev’s comment here was: “It is hard to believe Mr. Bauer, unless he can provide a comparison with Tesla on these three crucial parameters: price/kWh, kWh/kg, and kWh/m3. The lifetime of the battery slowly becomes the matter of management (thermal, 80% SoC, 80% DoD, peak consumption management) of the battery and less dependent on the chemistry of the lithium-ion cell (unless we are talking about different chemistries, such as lithium-air cells, liquid-flow cells, or some other exotic combination).”

Regarding Tesla’s batteries, Sven said that, using 18650 cells, “they are never going to achieve 20 years’ battery life…. If the battery is looked after carefully, perhaps eight years tops. If you regularly drive flat out or live in a hot region such as California, where the road can reach temperatures of 60, 70 degrees [Celsius], then perhaps only four or five years.”

I have to say, it seems odd that Tesla would warranty its batteries for 8 years and unlimited miles if “8 years tops” was actually the case and 4–5 years was more likely. With those claims, though, quotes from Sven are done. And [Edit: The preceding lines have been removed because I learned — or was reminded, since I must have read this before — that Tesla’s battery warranty does not cover degradation at all.] I’ll just reiterate again: it seems Sven was basing his comments on standard 18650 battery cells that are very different from Tesla’s battery cells. As Denis added, there are several other parameters to consider, and it seemed like Sven didn’t know what those were for Tesla’s batteries and made some odd assumptions.

I asked Tesla Motors a couple of times to look at the claims above and respond regarding expected Tesla battery lifetime (to 80% capacity), expected capacity after 10 years and after 20 years, and how it is that Tesla batteries are warranted for what this battery expert projected to be the top battery lifetime (to 80% capacity) for these battery packs. Unfortunately, all I got was a link to an article in the mainstream media that discussed Tesla Energy stationary storage products — nothing about the very different batteries used in Tesla’s cars — and there wasn’t really anything new (to me) or useful in that story anyway. [Edit: Tesla representatives also did not correct the assumption that Tesla’s EV battery warranty covers degradation to a certain point.]

So, we essentially have no detail from Tesla on these battery questions. What we know, though, is that Tesla’s warranty covers the battery capacity for 8 years (that is, the capacity shouldn’t drop below 80% of the initial rating until after 8 years). Assuming Tesla didn’t choose 8 years with the expectation that many batteries would just barely last 8 years (that would be stupid), I expect most batteries should stay above 80% for at least a decade. [Edit: The preceding lines have been removed because I learned — or was reminded, since I must have read this before — that Tesla’s battery warranty does not cover degradation at all.]

Now, taking all of this into account, let’s come back to the question in the title: “BMW+Samsung Batteries vs Tesla+Panasonic Batteries — Which Are Better?”

Better is obviously a subjective term, but it is typically going to be evaluated based on a balance of cost, performance, and lifetime. It’s hard at this point to say BMW’s batteries offer the better value when Tesla has been able to take the #1 spot in the large luxury sedan market and BMW i3 sales are mediocre. Not even considering Tesla batteries’ higher power density, relatively high upfront costs are simply not loved by consumers, and consumers tend not to be very long-term thinkers with such purchases. Very few are thinking 20 years out when buying (or leasing!) a car.

That said, we don’t even know if the BMW i3’s batteries will really hold up for about twice as long as Tesla’s, and there’s the point hinted at above that a Tesla battery that drops from 250 miles of range to 200 miles of range (80%) is still much more useful than a BMW i3 battery that drops from 80 miles of range to 64 miles of range (80%), or even 72 miles of range (90%). I think I can predict which price would hold up better on the used car market.

Nonetheless, the matter is a very interesting one to me, and there are fundamentally interesting points to debate on how these companies should approach battery technology options.

We’ll have more perspective on these matters in several years when Tesla Model S and BMW i3 vehicles are a bit older, and when we have more news on BMW’s i5 and other electric car plans and offerings. Will BMW actually be able to offer something similar to the i5 Tom Moloughney envisions for a price that is competitive with the Tesla Model 3? Or is that too much to ask while BMW uses long-life but expensive Samsung SDI battery cells? Will Tesla’s batteries continue to hold up better than expected, or will their degradation leave consumers wanting an upgrade and suffering from degraded resale values in a few years? Will Tesla and BMW both stick with their initial battery decisions, or will one or both of them change course? These are all questions that I’m eager to see answered as time unfolds the future of electric cars and their battery hearts.

*I didn’t know where to slip this in, but here’s one more interesting comment from Denis: “Additional feature that contribute to the cost, performance  and possibly to the life expectancy of the battery pack is how the pack electrically assembled. Tesla uses in the magnitude of thousands of 18650 cells, whereas the majority of others use commonly 96 or 192 cells. Each Tesla’s cell measures ~ 3,2 – 3,4 Ah, whereas the other use in the range between 60 to 94 Ah. In both of these approaches there are pros and cons. Tesla’s matrix style is more expensive to assemble, cheaper to replace a small cell, easier to control temperature on a cell level. The modular design of the others is pretty much the opposite of Tesla’s: cheaper to assemble, more expensive to replace a larger cell, and uneven or more expensive thermal control due to the lower diffusion speed into the bulk size of a bigger cell.”

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About the Author

is tryin' to help society help itself (and other species) with the power of the typed word. He spends most of his time here on CleanTechnica as its director and chief editor, but he's also the president of Important Media and the director/founder of EV Obsession, Solar Love, and Bikocity. Zach is recognized globally as a solar energy, electric car, and energy storage expert. Zach has long-term investments in TSLA, FSLR, SPWR, SEDG, & ABB — after years of covering solar and EVs, he simply has a lot of faith in these particular companies and feels like they are good cleantech companies to invest in.

  • Perttu Lehtinen

    I don’t think we should even care about the battery performance after ~20 years of use. I assume that a replacement pack would be relative cheap then.

    • Bob_Wallace

      Resale value. Get part of your purchase price back in addition to what is paid for the scrap metal.

  • SkyHunter

    Tesla will be switching to their new 20700 cell sometime next year. Which makes this analysis a bit moot.

  • Bob_Wallace

    Here’s some data on Tesla batteries. It looks to me the furthest data point is about 240 miles from a battery that started at 265 miles. That’s 90.6% range remaining. At 130,000 miles.

    Based on annual average driving miles of 13,000 that’s ten years of driving for most people.

    It is a small sample, but that’s what we’ve got at the moment. Limited as it is, it suggests reaching 200,000 with 80% capacity remaining.

    And here’s a cleaner version of the article graph. One that didn’t get fuzzed out by going from png to jpg.

    • Bob_Wallace

      This mostly a test –

      I’ve been talking with Disqus about changing their image handling. Looks like they’ve modified their software. Now one can embed an image from their own files inside the text rather than have it only display at the end of the comment.

      Type something. Click on image icon and select something from your files. Type some more.

      Image displays inside the text, like it has down with image linked from another web page.

      BTW, this image. A group of cells similar to those used by Tesla. They have been cycled 6 to 8 times per day for 8 years. 20,000 cycles and holding well. Made it to about 1,200 cycles prior to hitting 80%. 80% of a 250 mile range EV would be 200 miles. 20,000 cycles at 175 miles would be 3,500,000 miles.

      More realistically, 200,000 miles in a car and then a heck of a lot of years doing utility scale storage. If this holds it would mean that a worn out EV would have significant dismantling value because the battery pack could be sold on. Rather than a “$45” crush value the battery pack would be worth a few thousand.

    • vensonata .

      The original graph can be clicked on to bring out the details of mileage etc. See my comment above for the exact mileages of a few examples and the capacity percentage of the battery. The batteries are quite variable it seems, but you will see some already in the low 80’s.

      • Bob_Wallace

        There are a few data points well below the norm, if we’re talking about the same graph. That could indicated some bad cells in that pack that need to be replaced. Overall the data I’m looking at is pretty tightly clustered.

        Of course this is a small sample. I’d really like to see what Tesla’s data look like. I wonder if they routinely get feedback from the cars.

      • Bob_Wallace

        I took the data from the owner survey on Plug in America and plotted it out.

        Some information is missing in the survey. One can’t tell whether a S85 is a 253 mile range P85D Ludicrous or a 270 mile range P85 AWD. Same for the P90, there’s a range of ranges from 270 to 294 and for the P70 with a range of ranges from 230 to 240.

        So I graphed a couple of ways. First graph (blue data points) uses median range values for each model. (For the P70s I used 235 miles.) For the second graph (red data points) I used the high end of the range. (270 miles for all S85s.) That means that there is some slop in the numbers, but comparing the two there’s not a huge amount.

        I used the median and max ranges to calculate percent capacity remaining and plotted that as a function of miles driven.

        So –

        What I’m seeing is most of the battery packs are holding up very well. There are a few packs that are low and might be packs needing service before the end of their warranty period.

        • vensonata .

          Yes, the majority are holding up well. The stragglers may be because of climate or glitches. The other possibility is the fact that one can recondition the battery by draining and fully charging it apparently, and this restores a certain percentage of capacity. The low batteries may have owners who are not aware of that. Tesla seems to advise them of that protocol

          • Bob_Wallace

            If you look at the graphs there are a few that are below 80% and all have low accumulated mileage. Less than 40k miles.

            I’m thinking that their battery packs contain some cells that were substandard and need to be swapped out.

            I haven’t found the percent range loss before the battery warranty kicks in. I’ve seen people say 30% (70% capacity remaining) but haven’t found anything official.

            If it’s 70% then the people who are now below 80% should be able to get the bad cells (if that’s the problem) replace after a bit more drop.

            BTW, the S40s and S60s dominate the lowest range remaining list. Earlier generation batteries?

          • vensonata .

            What is weird is that the Tesla 40 has a 60kwh pack! So if anything it should hold up better than an 85 kwh pack. But perhaps lithium batteries are as individual as lead acid, there are always a few laggards that drag down the whole bank. The earlier batteries may have consistency problems in manufacturing process. Hopefully this has been corrected at the gigafactory.

          • Bob_Wallace

            Musk has stated that they are changing the batteries as they go along. I’m going to go back to the data and see if most of the “worst” batteries are in earliest manufactured cars.

          • Bob_Wallace

            10 out of 315 (2.9%) report less than 85% original range.

            Out of that ten 7 are 2013 models, 1 is a 2014 and 2 are 2015.

            All of these have been driven less than 40,000 miles so it’s not the oldest cars have the most cycles on their batteries. The two 2015 cars in the group have 8.7k and 10.8k miles. Their batteries are way down with less than one year of average US driving.

            It’s just looking like some bum cells to me….

          • vensonata .

            Another interesting stat would be “What is the least degradation over 100,000 miles?” That would be something to learn from. What climate? How is it driven? Charging strategies?

  • Illuminati

    An article comparing the batteries used by BMW and Tesla, and which does not mention the Gigafactory and the impact it will have. (We talk about a 30% cost reduction!) This is a total lack of professionalism.

    Note: Tesla Gigafactory to be Inaugurated on July 29th.

    • Frank

      Comparing what one company says they are going to be able to do in the future, to a shipping product is not fair. Don’t get me wrong, I believe Tesla is going to make batteries at the very least cheaper, and likely better too. But that’s tomorrow. The article did talk about the GF, and the absence of information regarding a similar level of effort from BMW.

  • Shyam T

    I dont know which combo has the best battery but I do know which combo has more money at their disposal. That is what matters invariably.

  • hybridbear

    You can buy a large, fully electric, premium-class sedan with >200 miles of range from Tesla for $66,000 before incentives, and BMW’s subcompact (yep, subcompact) i3 costs $51,400 with under 100 miles of range. There are other factors at play as well — the i3 is made of rather expensive carbon fiber, for example, and the Model S comes with Supercharging — but it seems like a safe conclusion that BMW’s batteries are much more expensive than Tesla’s.

    Perhaps the BMW is so much more expensive because BMW doesn’t need to sell the i3 right now to be profitable. Tesla needs to sell enough cars to stay in business. I’d guess that Tesla’s gross margin on the Model S is less than BMW’s gross margin on the i3.

    • Matt

      BMW means “Best Motor-vehicle in the World” so yes of course there is a bit of a mark up for that. 😉
      But as for the true margin on a S verse i3, I do not know. The hard part for BMW is when do they really go after the EV market, at that point they would want to use there deep pockets to get market share which might lead to lower gross margin for a time. If they wait too long then it will be hard to get market share in EVs.

      • Knetter

        Bayerische Motoren Werke, German for Bavarian Motor Works.

    • Illuminati
  • Ken

    The Tesla battery is clearly vastly superior to anything BMW has. The Tesla is much faster, can charge much quicker and has more than double the range. BMW has completely failed to show or even announce any battery that can compete with those specs.

    It is also pure idiocy to claim that the BMW batteries can last 20 years with zero data to back that up while Tesla has lots of data that proves their batteries are on track to last, at least, 10 years.

    It is also quite brain dead to increase the cost of a battery just to try and make it last 20 years since the price of replacement of a Tesla battery is less than the cost of fuel for a gasoline car over the same period, anytime after the Tesla 8 year warranty.

    BMW has proved completely clueless in BEV design which is why the i3 is such a huge sales failure. The Model S outsold it, last month, by over 6 to 1, even though the Model S is more than twice as expensive and the Model X outsold it by almost 4 to 1.

    • Jørgen Mo

      The i3 is superior in many ways. It is built with light weight materials and uses only 60% of the energy of the heavy Tesla. i3 production is also far more green that Tesla and this is the whole point of BEV cars. Tesla seems to miss that. Not to mention the interior, Tesla have a lot to learn there, which is no surprise as BMW has been designing cars for exactly 100 years now. I’ve driven both the i3 and a Tesla S and although the S is quicker it is no way near the i3 when it comes to driving pleasure.

      • Are Hansen

        Why is the production of the i3 greener than the Tesla Model S ? Are you thinking of the carbon fiber body? Well, Teslas aluminum can be recycled totally, endlessly. But I guess the carbon fiber is mixed with plastic of some sort, and harder to separate/recycle?
        Of course the i3 uses much less energy driving than the Model S. The Tesla is a big, roomy car, whereas the i3 can only seat 4 people and much less baggage.
        To me it seems strange that BMW spent their money for an expensive carbon fiber body, instead of using them for a bigger battery

        • Illuminati

          “Why is the production of the i3 greener than the Tesla Model S ?”

          The BMW i3 he drove was green, and the Tesla was white.

        • Perttu Lehtinen

          Carbon fiber is impossible to get recycled properly.

      • Illuminati

        The Tesla P85D consumes 24% more energy than the i3 BMW.
        But the Tesla P85D is 80% heavier than the BMW i3.

      • Ken

        Wrong. The i3 is not superior to the Tesla in any way. If you understood basic physics you would understand that small, slow, cramped vehicles will always require less energy to move than large, fast vehicles. It has nothing to do with technology.

        If Tesla ever decided to make a slow, small cramped vehicle, they could easily make it as energy efficient. As it is, their fast, comfortable cars get close to 100 mpge which is excellent.

        You also don’t seem to realize that Tesla already made a very lightweight, carbon fiber car with the Roadster, so they are years ahead of BMW on that front as well.

        The i3 interior, as well as all BMW interiors, are very old fashioned, not ergonomic and cluttered with buttons. The fact that the company is 100 years old reflects their dinosaur designs that the sleek, simple Tesla massively outsells.

        To try and claim that there is more driving pleasure in a small, slow, cramped car than the fastest production sedan on the planet that Motor Trend has called as smooth as a $330,000 Rolls Royce is laughable.

        The fact that, the more than twice as expensive, Tesla easily outsold
        the failed i3 by more than 6 to one makes that claim even more silly.

        Tesla also easily outsells BMW gas cars in its class in both the US and Western Europe so it is clear that it is the 100 year old dinosaur company that has a lot to learn from Tesla.

        And they better hurry up because they are still years behind.

      • Perttu Lehtinen


  • mikgigs

    The batteries in EVs(e.g BMW) are never used for the max range for the reason of charge decline. This means that there is about 10 percent reserve if the battery start to fade capacity.So, the article purely speculate swith range declines.

  • Steve

    Hear Ye or Here Ye! No mention of Dr. Dahn? Sacrilegious!

    Tesla has “Dr. Battery,” lithium doctor that is:
    “Awe-struck by Tesla’s new “ludicrous” speed, the media mostly dismissed (or missed) Musk’s comment about improved battery cell chemistry. However, introducing silicon into automotive-grade lithium-ion cells represents a huge milestone for the EV (electric vehicle) industry. Silicon is widely considered to be the next big thing in anode technology, because it has a theoretical charge capacity ten times higher than that of typical graphite anodes. “It’s a race among the battery makers to get more and more silicon in,” explains Jeff Dahn, a world-renowed battery researcher. Unlocking the potential of silicon could give a company the edge needed to become an early leader in advanced battery technology. So it’s no surprise that, as Jeff Dahn elaborated, “the number of researchers around the world working on silicon for lithium-ion cells is mind-boggling.”

    Quartz also weighed in, noting that Musk “didn’t mention that, for the automobile industry, Tesla’s use of silicon is no small thing—indeed it’s a first. While battery researchers around the world have attempted the feat for years, until now no one has managed to put the potent but rambunctious element [silicon] into a working vehicle battery… It’s a mystery as to why Musk—extraordinarily vigilant and purposeful when it comes to his public image, and not one to shy from a chance to boast—passed up an opportunity to flag a scientific coup. Tesla didn’t respond to an email on this issue; in response to an earlier query regarding how much silicon the anode contains, a spokeswoman declined to add to Musk’s remarks in the call.”

    “Hmmmm. But, wait… let’s backtrack, who exactly was that guy, Jeff Dahn? Well, this summer the Wall Street Journal reported, “Tesla Motors Inc. has locked a leading advanced battery researcher into an exclusive partnership… Jeff Dahn, a professor at Dalhousie University in Nova Scotia known for his work innovating lithium-ion batteries like those Tesla uses to power its Model S sedan, will cooperate with Tesla researchers. Now working on a project with 3M Co., he will enter a research partnership with Tesla when his current work is completed. [Dahn] patented a nickel-cobalt-manganese chemistry for battery cathodes that is now commonly used in the industry. He is also the leading researcher on why lithium-ion batteries fail… [and] one of his areas of expertise is silicon anodes.”

    • vensonata .

      You must be new to Cleantechnica. Jeff Dahn, is frequently brought into the battery discussions as a leading Guru.

      • Steve

        Versonata, not new, but okay. I brought him into this battery discussion. I just felt somewhere within the article it makes sense to mention Jeff Dahn because he is now the lead architect for Tesla batteries. Sorry I didn’t knock before walking in. 🙂

      • Steve

        No, not new to Cleantechnica. I was just bringing him into the discussion like we frequently do. I felt is is germane to this discussion because Elon has admitted to using silicon in the anodes. Nobody really knows the true cost and chemistry of Tesla’s batteries.

  • dcard88

    Does the I3 still use the same batteries Bauer was discussing 3 years ago?

    • Jouni Valkonen

      probably yes as BMW as typical product cycle for BMW is about 7 years.

      • Jørgen Mo

        Current i3 batteries are 94Ah compared to the previous 60Ah, not sure if there are other differences.

  • vensonata .

    The article says: “Tesla’s warranty covers the battery capacity for 8 years (that is, the
    capacity shouldn’t drop below 80% of the initial rating until after 8
    years)” However 80% is not specified: (Copied directly from the Tesla Warranty:) “Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered under this Battery Limited Warranty.”
    So to be clear, you get 8 years unlimited mileage but no guarantee that the battery will charge to 80%…or even 50%.

    • Freddy D

      Very interesting. Would love to hear more on this subject if anyone know what tesla really warrants.

      • Ivor O’Connor

        Battery Limited Warranty
        The Model S lithium-ion battery (the “Battery”) is an extremely sophisticated powertrain component designed to withstand extreme driving conditions. You can rest easy knowing that Tesla’s state-of-the-art Battery is backed by this Battery Limited Warranty, which covers the repair or replacement of any malfunctioning or defective Battery, subject to the limitations described below. If your Battery requires warranty service, Tesla will repair the unit, or replace it with a factory reconditioned unit that has an energy capacity at least equal to that of the original Battery before the failure occurred. Your vehicle’s Battery is covered under this Battery Limited Warranty for a period of 8 years or for the number of miles/km specified below for your Battery configuration, whichever comes first:
        • 60 kWh – 125,000 miles (200,000 km)
        • 85 kWh – unlimited miles/km
        Despite the breadth of this warranty, damage resulting from intentional abuse (including intentionally ignoring active vehicle warnings), a collision or accident, or the servicing or opening of the Battery by non-Tesla personnel, is not covered under this Battery Limited Warranty. In addition, damage resulting from the following activities are not covered under this Battery Limited Warranty:
        • Exposing the vehicle to ambient temperatures above 140°F (60°C) or below -22°F (-30°C) for more than 24 hours at a time;
        • Physically damaging the Battery, or intentionally attempting, either by physical means, programming, or other methods, to extend (other than as specified in your owner documentation) or reduce the life of the Battery;
        • Exposing the Battery to direct flame; or,
        • Flooding of the Battery.
        The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use. Loss of Battery energy or power over time or due to or resulting from Battery usage, is NOT covered under this Battery Limited Warranty. See your owner documentation for important information on how to maximize the life and capacity of the Battery.

        and then

        Infinite Mile Warranty

        Elon Musk, CEO August 15, 2014

        The Tesla Model S drive unit warranty has been increased to match that of the battery pack. That means the 85 kWh Model S, our most popular model by far, now has an 8 year, infinite mile warranty on both the battery pack and drive unit. There is also no limit on the number of owners during the warranty period.

        Moreover, the warranty extension will apply retroactively to all Model S vehicles ever produced. In hindsight, this should have been our policy from the beginning of the Model S program. If we truly believe that electric motors are fundamentally more reliable than gasoline engines, with far fewer moving parts and no oily residue or combustion byproducts to gum up the works, then our warranty policy should reflect that.

        To investors in Tesla, I must acknowledge that this will have a moderately negative effect on Tesla earnings in the short term, as our warranty reserves will necessarily have to increase above current levels. This is amplified by the fact that we are doing so retroactively, not just for new customers. However, by doing the right thing for Tesla vehicle owners at this early stage of our company, I am confident that it will work out well in the long term.

        – Elon

    • Ken

      There is clear data that shows that Tesla batteries are on track to last over 10 years with capacity easily over 80% so there is no concern there.

      • vensonata .

        Here are some specific mileage and Battery capacities on various Tesla’s. These are from a graph voluntarily submitted by Tesla owners.
        Model S 60 1) 37,400 miles/155 mile range =74% capacity

        2) 39,700 miles 83% capacity
        3) 28,174 miles 85% capacity
        Model S 85 1) 34,620 miles 86% capacity
        2)69,900/ 91% capacity
        3)34,620/ 86% capacity
        4)54,400/ 89% capacity
        These are specific examples. You can see that 80% capacity may be reached well before 8 years for high mileage drivers. The question is: what happens after 80%? Apparently the reduced capacity slows drastically and the car may have many thousands of cycles between 80-60%. However the range is reduced significantly.

        • Bob_Wallace

          The S60 would have been an early model. It’s capacity loss might not be representative of more recent battery formulation.

          The other examples are above 80%. What one might expect from lithium-ion cells is a drop to 80% over 1,000 or so cycles with a large part of that drop early on.

          Here are a couple of graphs of range over miles driven.

          The Tesla S85 which has accumulated the most miles still has 90% capacity left.

        • Ken

          No. You need to look at the actual research. The data submitted by Tesla owners clearly shows a trend average of about 95% at 100,000 miles. And even at over 130,000 miles a Tesla still had over 90% range. The average driver will only put on 120,000 miles in 8 years. So there is no concern, exactly as I said.

          • vensonata .

            I gave you 3 examples of Tesla S 85 that were less than 60,000 miles and were below 90%…2 in fact, at about 86% capacity remaining. That means that battery packs are not consistent, they are subject to wide variation, perhaps according to driving conditions, but also just the battery management system and individual cell difference.
            The overall average may indeed by higher…let us hope.

          • Joe Viocoe

            I don’t think it is fair to cherry pick outliers to make blanket, generalized statements.
            Of course there are wide variations. Every automaker has them. It does matter how many of them, and how far they vary. A very few numbers of vehicles which vary greatly, doesn’t impact the statistics very much.
            This is why we have Standard Deviation. To account for, but not give too much weight to these outliers.

            I agree that Tesla doesn’t “guarantee” specific capacity loses over distances traveled… but I don’t care too much if they don’t. The statistic bear it out over time.

          • vensonata .

            Yes, outliers do not make generalized statements. They just show the full range of what is possible. I think Tesla has a policy of calling up Tesla owners whose packs are showing early aging signs and offering re conditioning or replacement just so negative publicity does not grow.

          • Ken

            Wrong. The vast majority are consistent with over 90% of range after the average distance traveled in 8 years.

            There will always be outliers which indicate either a problem with the battery or user abuse but have nothing to do with people having concerns over Tesla battery life, exactly as I said.

            Picking outliers is statistically meaningless and very misleading.

  • wattleberry

    This marks the beginning of an ongoing and crucial comparison at the heart of EV development, fascinating, not only for the products themselves but, more than ever before, between the US, which has a tradition of much cheaper vehicles, and other countries which have hitherto been able to shelter behind a history of ‘parallel development’. Not any more.
    Bring it on, it can only benefit the consumer!

  • Ivor O’Connor

    Sven Bauer knows how long his batteries will last down to the month decades away? I smell massive amounts of BS.

    I’m concerned about the BMW car being made of carbon fiber. I’ve seen countless carbon fiber racing bike frames collapse within a few years. Carbon fiber seems like it’s great for a season or two but anything more and you are risking your life. And BMW has the audacity to say their batteries are going to last in a carbon frame for 20.9 years?

    Then didn’t we see an article earlier this year with a beautiful graph showing the battery used in the Tesla being cycled repeatedly millions of times over the course of 6 years? The graph gave every indication that a Tesla car could get four million miles at close to 80% of the original capacity. I have my doubts about this but apparently we do have real empirical evidence those Tesla batteries should last decades. Maybe BMW could comment on this? “Why Herr Bauer do you believe the something contrary to the empirical data gathered on the 18650 cells in this article here?”

    Finally, if the energy to weight density on the KIA batteries is almost 50% greater than that of the Tesla’s then I’m expecting 150 kWh battery packs from Tesla in the next five years. Then we’ll start seeing Tesla’s that can do road trips that don’t require a 40 minute charge for every two hours of driving.

    • GlennM

      Hi Ivor,
      no need to worrry about Carbon fibre. Bikes are made extremely light and are designed for short life. The Beechcraft Starship, made in the early 1980’s out of CF has been tested and after 30+ years shows no loss in strength. In engineering terms once you go over a safety factor of about 1.8 for CF then fatigue life is infinite. That is an engineering term…not saying they will last for ever !

      • Ivor O’Connor

        Good to know.

      • Matt

        Yes the highest end frames are built very light and since used by racers with backers long life is not considered a requirement.

    • SkyHunter

      You can get 2 hours of driving in 20 minutes at a Tesla supercharger, about 6 miles per minute.

      • Ivor O’Connor

        No, starting at a 10% charge you can get between 4 to 5 miles per minute in the 21.5 minutes it takes to get to a 40% charge.

        If you start at 10% and charge to 65% it takes 42.5 minutes at an average of 3.3 to 4 mpm. And it gets you 140 to 178 miles depending on the Tesla. Or on road trips you inchworm your way about two hours of driving for every 45 minutes or more of charging.


    • Perttu Lehtinen

      Bicycle carbon fiber frames last “forever”. It’s extremely good stuff. The only drawback is that it might be very hard fix. That’s where steel shines.

  • jimbo

    I’ve been reading some owner reviews of the BMW i3 and some were saying the real range was not nearly what was advertised. In some ways there were only getting the 20 yr predicted range or so, from the start. I don’t think Tesla owners seem to be complaining about this sort of problem with its predicted range. Does anyone have extra info on this? By the way, the general owner reviews of the i3 were very positive.

    • Jørgen Mo

      The range of my i3 is as expected and around 160 km as stated by BMW, even a bit more with optimal conditions.

      • johnbl

        Well with an average of 4.5 miles/kWh ..I’m seeing 85-90 mile range (135-140 km) as typical for my BEV i3.

      • Ken

        You are a clear outlier as that is not what the vast majority of owners are saying.

        They are saying much less.

  • onesecond

    I really can’t take Sven Bauer too seriously, especially when I look at the first graph in this article. Looks like he doesn’t know anything about Tesla batteries. If the i3 really hold up this long, then they will be useful for secondary use as storage, but the owners of the i3 will probably not wait 20 years to switch to a more long-range EV considering all these new EVs that will be coming out.

  • JamesWimberley

    It seems odd that Tesla get a higher energy density from smaller cells, when these inherently have more packaging that doesn’t contribute to the electrochemistry. But then, I am not an engineer.

    • Brunel

      It must be the chemistry used by Tesla/Panasonic. Not the shape of cells.

  • Are Hansen

    Going for cheaper batteries with a shorter lifespan seems best at the moment. In far less than 20 years we will have dramatically better battery tech with higher density and lower price and weight

    • Jouni Valkonen

      I would say that in less than two months we have these dramatically better batteries on market as new LG batteries are entering to EV markets.

      For example comparing Tesla Powerwall and LG Chem Resu 7.0H

      capacity: 6.4 kWh | 6.4 kWh
      cost: 4000 euros | 3000 euros
      cycles: 4000 | 6000
      weight: 100 kg | 75 kg.

      This makes that LG batteries have lifetime costs less than half that of Tesla batteries. And if Tesla batteries were right on the verge of commercial feasibility, LG batteries are commercially viable by huge margin in every application in road transportation and grid storage applications.

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