BMW Batteries Have 15-Year Life In EVs


The 2017 BMW i3 got an upgraded 33.4 kWh battery, good for 114 miles of range

BMW’s head of battery development, Andreas Raith, interviewed by the CarAdvice, says that lithium-ion batteries in all-electric and plug-in hybrid cars are designed for “15 years and beyond.”

BMW i3 Battery opened up

There is nothing to worry about as BMW took a conservative approach to achieve 70% of battery capacity after 15 years. The field data collected so far indicates that results are better than envisioned.

Life-expectancy for BEVs and PHEVs is on par with ICE cars.

To make batteries durable, BMW utilized thermal management system with liquid cooling.

Andreas Raith said:

“It’s not a marketing statement, those batteries are designed to last as long as the vehicle,”

“We can prove that with the field data that we see today coming in from our existing fleet of plug-in hybrids… it’s fair to say and I think it’s a statement for the entire industry and community, everyone is so concerned about [battery] life time and the engineering community as a whole takes a very conservative approach to preserving those batteries.”

“BMW specification in case of durability is no different between combustion engines or battery driven vehicles.”

When 15 years pass, capacity, available power and efficiency will fade,but the battery still will be working. Some may keep driving the old car, while others will maybe take the battery out for energy storage systems before recycling.

“As soon as the [recycling] pipeline fills up, and it takes so many years to fill up, there is substantial value in those batteries.”

“On the automotive side, we expect the pipeline to be pretty solid, and those materials lithium, nickel, copper, there is no toxic in there, it’s just metals and its very recyclable.”

Source: CarAdvice

Category: BMW

39 responses to "BMW Batteries Have 15-Year Life In EVs"
  1. Djoni says:

    AFAIK, the cooling of the BMW pack is done with the refrigerant.
    Althought, it condensate to liquid in the condenser, it,s vapor or gas in the evaporator stage, and this is send to a plate beneath the battery pack.
    No liquid ever touch the pack.
    I think it’s a very clever and efficient way of cooling that BMW chose to do.

    1. L'amata says:

      I wonder how they warm them up in cold weather..

      1. alohart says:

        Warming the battery pack to at most 10º C / 50º F prior to driving while plugged into an EVSE is done via resistance elements below the pack.

        I don’t believe resistance heating is used while driving. Instead, the electrical resistance of current flowing through the cells while driving heats the cells naturally.

    2. Bill Howland says:

      If you mean that literally that no ‘liquid’ touches the batteries (I had thought this was a supposed (I always thought trvial) improvement on the indirect expansion systems used by everyone else) – in other words vaporized (boiled) refrigerant is touching the batteries, that would mean boiling the refrigerant first, and the typical refrigerant, 134A, has a relatively low vaporous specific heat, meaning the refrigerant ‘evaporating temperature’ would be much colder than necessary. If it is a direct expansion system, I don’t see any harm in just letting the refrigerant boil in the proximity of the batteries since then the high latent heat of vaporization of R134A would remove the heat at a relatively HIGH (i.e. efficient) evaporation temperature.

      I know that sounds like tech gobbledy gook to some, but what I mean is, your freezer set to -20 degrees F takes many more KWH/TON of cooling than does your window air conditioner set at 76 degrees F. WHY? Its easier to ‘pump’ heat from 76 degrees to 105 degrees F than it is to pump -20 degree F heat to 90 degrees F.

      If the BMW system is a true direct expansion system and avoids the chilled water loop of absolutely everyone else, that means the battery compartment has to be sealed to withstand 60-100 PSI evaporating pressures and everything must be totally leakproof INCLUDING all wiring entering and leaving the compartment. That is why I really DOUBT their system is anything special other than using piping to transfer the boiling refrigerant to an aluminum plate, and in that sense ONLY is the system direct expansion (i.e. it works just like your fridge or central air conditioner), and minimizing sealing requirements for the refrigerant system and there is actually no refrigerant physically touching the batteries at any time other than at the other side of an aluminum plate.

      1. Bill Howland says:

        If one of the advantages of BMW batteries are ‘Liquid Cooling’, I’d like to know how that materially differs from the ‘Liquid Cooling’ I had on my Roadster, Volt, ELr, and Bolt batteries – where the liquid is water with some ethylene glycol added to prevent it from freezing and busting everything up.

        If BMW’s system is a true direct expansion system, than the only thing that is ‘liquid cooling’ prior to hitting the batteries is the REFRIGERANT ITSELF!!

        EX: 110 degree F Liquid entering the evaporator, where the evaporating equilibrium temperature is 37 degrees F, must ‘waste’ refrigerating effect COOLING ITSELF first down to 37 degrees F before it can boil other ‘non-waste’ refrigerant to do any useful cooling.

        So the German BMW pseudo-tech statement is actually bogus since it is the vaporous refrigerant that does the cooling – unless of course this is just a plain chilled water system as absolutely everyone else uses as illustrated.

        1. Bill Howland says:

          Of course, ‘excess refrigerant’ evaporators, where the majority of the refrigerant boils inside the proximity of the aluminum plate (if this is a direct expansion system) – the rest of the refrigerant is ‘wasted’ to lower the other ‘rest’ of the refrigerant down to evaporating temperature – then this ‘majority’ of the liquid awaiting to boil is just called a FLOODED evaporator, something they’ve used for 100 years.

          I find it hard to analyze exactly what the BMW system is, since they could spell it out in plain english. (or plain german). But doing so would indicate this is being done the same was as any kind of refrigeration has been done for over 100 years now, and it wouldn’t sound so great in advertising brouchures.

          1. Will says:

            You completely lost me and probably lost the majority of readers. This is too technical 🙂 I don’t even look into it that much. If the cooling system works, then it works. If it doesn’t, it doesn’t.

      2. Peter says:

        Totally agree.
        Tesla’s construction works fine why do something else.

      3. Steven says:

        Wait, you mean not everyone understands basic Thermodynamics?
        Well, that would explain all the crazy ads I use to see in the back of PM magazine.

  2. Brett says:

    Hmm. My 6 month old Leaf battery is already at 91% according to Leaf Spy. Sure though, maybe in 15 years it will be above 70%.

    1. Bryan says:

      Hmm, my leased Leaf will go back to Nissan in September and has 34K miles. Still 10 bars and full range. I took it into the dealership a couple of months ago and they tested the battery. They said whatever I am doing keep it up. Negligible degradation so far.
      It is interesting how some of them last and others don’t.

      1. Bryan says:

        Did it again, 12 bars. All of them are still available. 10 white and 2 red.

      2. menorman says:

        I bought my Leaf used at 30k, it lost its first bar at 37k. Pushing 50k now, haven’t lost any additional bars yet. 2013 24kWh with no DCFC in SoCal now, but it spent most of its life in the Yay Area.

    2. philip d says:

      I think all anecdotal experiences with Leaf battery pack longevity will be outliers out of the entire pool of EV battery packs and their long term performances.

      The Leaf is the only major volume EV that still doesn’t use an active battery management system that makes use of active cooling whether it be liquid or refrigerant.

      Because of this the Leaf will continue to show inconsistent pack performance depending on many different variables and shouldn’t be representative of EV battery packs in general.

    3. Tom says:

      Hmmm…the article is about BMW which did a whole different thing.

    4. John Doe says:

      The New Leaf, that comes with the upgraded battery will have thermal management.

      1. wavelet says:

        Source? I’ve seen folks here say they _hope_ that’ll be the case, but AFAIK there’s been no statement on this.
        Some people may be basing it on the current-gen e-NV200’s pack apparently having active cooling, but again, not proof.

        1. simone says:

          Leaf 40kwh will still use AESC cell without thermal management , so they will fade soon.
          Leaf 60kwh is a rebranded Renault Zoe2 , it uses LG cell with active thermal management and have the correct charging port (CCS Combo + 22kwAC ) , the Zoe is well known for his long life battery

  3. Brett says:

    Yeah. Well in fairness my 2011 Leaf got a new battery added in July 2017. It sat at 100% and 99% through the hot summer months, then took a dive when winter came. So maybe it is just the winter. I’m not upset though. I only paid 20% or $1290 for the replacement battery. I just worry about BMW giving customers wildly unrealistic expectations. Sure my battery lacks liquid cooling. But even Spark owners have noticed drops in range over time. Maybe it’s better to promote cheap battery replacement costs over (likely) impossible battery life.

    1. pjwood1 says:

      Not “wildly unrealistic”. Teslas lose 2-4%, then stabilize. Few ever report more than 5-10%. I would think of it in terms of n initial plateau loss. Can’t say anything about 15 years, yet.

      1. SJC says:

        Tesla Model 3 said 70% after 10 years, I heard nothing about battery pack replacement price.

  4. William says:

    Has the battery warranty been revised/updated to a newer 15 year/180K mile / 70% capacity degradation policy?

    Kudos to BMW engineers, if they have actually managed the above remarkable feat, in providing this warranty for their batteries thermal management system / capability. This BMW demonstration, just shows how flawed and short sighted the Nissan Leaf engineers were in going without any battery TMS.

    The 2016-17 Nissan Leaf, with its 30 kWh battery, currently carries a 8 year/ 100 k mi. degradation warranty. (8 of 12 capacity bars on the dash display) representing approximately 30% degradation at roughly 70% battery capacity.

    1. Jason says:

      Actually, Leaf losses first SoH bar at 15% then the others at either 6.5% or 7.5% (can’t remember which), so by the time you lost 4 SoH bars you are down to either 65% or 62%, not 70%.

  5. Tom says:

    Hey wait…I’ve been assured by posters here that BMW is clueless. This guy is an engineer…no possible way he is right.

    1. mx says:

      This isn’t
      Possibly, you’re confused?

      1. Nick says:

        Hahaha! +1

        Looks like the original poster is lost. 🙂

  6. Some Guy says:

    I’m quite sure that lithium ion batteries can achieve a long lifetime. I have seen a commercial cell go beyond 5000 cycles (charged and discharged completely) and had over 75% capacity left (note, not lithium iron phosphate cells, were this is standard). Also longevity is not a problem, apparently. I have a 15 year old pack that is still operational (at around two thirds of the original capacity), powering a notebook for quick on site service of older machinery and a 17 year old single cell (about the same performance). And that is tech from, well, more than 15 years ago, when the manufacturers did not really care how long the cells should work. They can be engineered to die early, so one has to buy a new phone. They can be engineered to last long, for EV applications.

  7. MalcolmM says:

    I’m trying to get up to speed on my understanding of the lithium batteries currently in use in EV cars.

    My only experience with lithium batteries is lithium polymer (lipo) batteries in remote control planes. With lipos, we have found that we have to avoid as much as possible keeping the cells at full charge (4.2v per cell for most of our lipos). Flyers who fully charge their lipos and then leave them sitting for days and weeks report much shorter cycle life and capacity retention.

    Is there any similar effect in EV car lithium batteries? My plan when I buy an EV car in a year or two was to try and avoid keeping it fully charged as much as possible, particularly if I don’t plan to drive it for a few days. Would I be wasting my time?

    1. alohart says:

      An EV’s battery management system prevents its battery pack from being charged to its absolute maximum charge level. In an i3 for example, the maximum usable charge level is ~95% with the minimum usable charge level ~10%. Nevertheless, a battery cell remaining at 95%, especially in warm weather, would almost certainly degrade faster than a cell that remains at a lower charge level.

      Many U.S. EV owners can’t be bothered to restrict the charge levels of their battery packs, maybe because most of them lease and don’t care about battery pack longevity. It’s easier to just plug in an EVSE when arriving home and to unplug it before departing the following day.

      We plan to keep our i3 for many years, so it’s not a problem for me to restrict the charge level unless I need full range the following day or I want battery cell balancing to occur which happens only at high charge levels.

      1. Will says:

        A good EV will restrict the charge level by default and require the user to manually override the limit if they’ll be going on a road trip. Tesla require you override the 80% limit each time you plug in.

    2. Asak says:

      Yes, you should do that. It may not be necessary, but it can only help. I only charge my e-Golf to 70%, unless I know I need the max range and then I override the charge timer (the e-Golf has a button next to the charge port that makes this easy).

      Of course the other side of the coin is to try not to run the battery all the way down either, although sometimes it will inevitably happen (not all the way flat but close).

  8. Steve says:

    Let’s assume 15,000 miles per year average.

    70% after 15 years? (225,000 miles)

    Tesla cars are currently tracking to have 80% after 520,000 miles, which is 34 years.

    1. ekranoplan says:

      Not according to Tesla Bjorn : model x pack died completely at around 76,000mi. Whole 750kg unit was replaced.

  9. carcus says:

    When I look through this data:

    I don’t see 34 year Tesla batteries. I see 80% at year 8-10-12. So assuming a roughly linear degradation, Tesla batteries would be the same as BMW, …. about 70% at about year 15.

    BUT — I suspect a lot (the majority?) of people will not be happy with their EV once they reach 80%. … and year 8-10-12 will be the end. 15 years in a PHEV (i3Rex,..) .. yah, that might work.

  10. Phaedrus says:

    My february 2014 BMW i3 does not show a noticable degradation at 54.000km, although a software update has freed some extra capactity some time ago. I do drive spirited from time to time, but I avoid sustained high current discharging, like driving fast on the highway. Most of the time I charge to 100%, but after a full charge, I drive a couple of 100 meters home from the public charging station. To my understanding, in doing so, there is much less risk of degradation due to sustained high pack voltage. And indeed, 100% charge is in reality 95% charge.

    1. ekranoplan says:

      Bmw recommend long full charge to help battery balancing. Degredation still around 3% per year even if not used

  11. Tony Marco says:

    Lovin’ my 2014 BMW i3 Rex !

    My December 2014 i3 Rex does not show any noticeable degradation either currently at 51,000 km, but I only charge to 85% daily, charging to 100% on occasion. But then driving right after, so it’s never sitting at 100% very long.

    Now with access to the Full gas tank, range extender has jumped 25-30% in winter.

    Looking forward to the 300km total range in the summer!

    1. Will says:

      and how often do you need the extender?

      1. Tony Marco says:

        Only use the range extender on trips out of town and sometimes when the charge stations are busy.

        On 51,000 km less than 2,000 km are on the range extender.

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