6 ms·

Modern EV Batteries Rarely Fail: Study

60 points by bilsbie 3y ago

r00fus 3y ago
I fully expect my 2017 EV to last for 15 years without significant degradation[1]. I see the usability of EV batteries like Solar panels - in about 10 years, they get to at worst 90% range, and are probably usable well into 20+ years. Battery tech is what makes our present and future tech economy possible [2]. [1] I don't baby my EV - always charge to 100%, use fast chargers, don't worry about getting it to 10% or lower. It has lost maybe 5% of it's rated capacity. [2] with apologies to CEO Morgan from SMAC.
- dainiusse 3y ago
  That is unrealistic expectation for 15 years, especially for a 2017 EV.
  - treffer 3y ago
    Is it? The article lists 2015 as the year where things improved a lot, 2017 is well past that. The numbers are low and even that's inflated due to recalls. I've seen >>10 year old laptops where the battery is still good enough to go from charger to charger. Just go to ebay and check out 2009 MacBooks. That's ~15 years now. I don't think this is unrealistic if you can live with the heavier degradation.
  - aetch 3y ago
    15 years is completely realistic, I only started having problems with my 2007 Ford Escape Hybrid after 17 years of heavy use and 260k miles. Keep in mind that 2007 was when the 1st generation hybrids were just coming out, too, so technology is much better today. Don’t forget that there are other parts of a car that degrades as well with time. Eventually most well used cars will have an engine or powertrain issue if they even make it to 15 years to use without being totaled in an accident or simply sold second hand or misused.
    - fransje26 3y ago
      The 2007 Ford Escape Hybrids were using a lot of shared parts with the Toyota Prius, so the battery pack is definitely not Li-ion. The newer high-density Li-ion packs will not survive 15 years without loosing significant capacity, if they survive at all.
      - aetch 3y ago
        The escape hybrid had a nickel cadmium battery. I don’t see why a li-ion battery pack wouldn’t be usable for 15 years with good battery management. Both battery and ICE cars have reduced performance and range due to capacity/efficiency degradation so replacing and recycling a battery or engine at 15 years to restore performance is not unreasonable. No car, EV or ICE lasts forever. Likewise, most people want to upgrade to a newer flashier car before 15 years.
        dainiusse 3y ago
        Because we have plenty of real life examples for cars that have a lot less age.
        satiric 3y ago
        The battery chemistry is completely different; You can't assume similar characteristics.
        fransje26 3y ago
        > I don’t see why a li-ion battery pack wouldn’t be usable for 15 years. For 2 reasons, primarily. First, Toyota chose nickel-cadmium batteries because of their higher charge-cycle life, at the cost of a much lower energy density (about half that of li-ion). Secondly, they designed their system so that the discharge rate and the discharge level of their battery pack stayed low, thereby maximizing the lifetime of their battery pack, at the cost, once more, of extra weight. So those two aspects combined mean that you can expect a much longer real-life usage of your battery pack before reduced performance becomes an issue. I fully agree that a battery pack replacement after 15 years could be considered reasonable (as long as the build quality of the rest of the car warrants it, which is not a given nowadays). But if the mean-time between replacement is around 5 years, then it becomes unreasonable.
  - audunw 3y ago
    Our 8 year old 2015 Kia Soul EV is about 15% degraded (on the worst cell, which could be replaced individually btw). Battery degradation is generally fairly linear between 100% to 70% SoH. So I don’t see why I shouldn’t expect another 8 years on it. It depends on how much it is driven of course. The mileage is probably a bit below average on that one. I have a short commute to work. We did some road trips in it though. You gotta take into account that old EVs with small batteries will probably often be used as a second car, and so used less often. That’s the case for us since we got a newer bigger car as our family grew. We don’t take the Kia on road trips anymore and my wife takes the bus to work.
PaulKeeble 3y ago
The projection on most of these batteries life times now is 500k+ miles before they hit 80% of their capacity. The car around the battery will be falling to pieces before they reach that point. Its not like there weren't quite a lot of ICE lemon vehicles with engine and other problems that caused issues, its always been part of any industry and there will still be packs in the future that don't perform as they should for as long as they are meant to. EVs generally will require less maintenance as they are substantially simpler vehicles with less moving parts.
- SV_BubbleTime 3y ago
  I’m an automotive EE. This may be a rating you heard somewhere but the truth with practical real-world use is… debatable. If you run these in a lab, ok, maybe, according to someone trying to sell you batteries. If you run your vehicle at a spread of -20F to 120F, absolutely not. I can promise you that the vehicles we are working on go past 2032 and they’re all still ICE. These EVa are just not replacements for ICE. They make great supplements and town cars. It’s a marketing failure, and I’m not sure the pie in the sky “your car will fail before your battery” claim is helpful. I’m pretty sure the only people that would jump on that are EV owners, which I am, and don’t.
  - LeFantome 3y ago
    Not sure what kind of EV you have. Ours goes over 150 km most weekdays, somewhere beteeen 20 km and 200 km on weekend days, and has taken the family on multiple 1000 km or more road trips now. My wife drives the EV most days. I cannot count the number of times I have been running late and had to stop to fill my gas guzzler up. It is freeway most of the way to work ( no gas stations ) and I have risked it more than once. The EV “tank” is full every morning so it never puts her through that. In practice, I have way more range anxiety in my ICE vehicle than my wife does in her EV. Supplements and town cars? If I could afford a new vehicle, my ICE vehicle would be the supplement.
    - dieselgate 3y ago
      You present a valid argument but I think comparing an EV being charged every morning to not always having a full fuel tank in an ICE, in the morning, is apples to oranges. From that perspective the EV has an advantage but it’s not a direct comparison.
dieselgate 3y ago
Cool study and great to see some data on this. The numbers seemed pretty good to start out with - lower single digit failure percentage - but then they get an order of magnitude more reliable to tenths of a percent failure. I’m mostly curious what happens when an EV has been neglected or left un running for long durations.
- metadat 3y ago
  The battery gets depleted in my rivian pretty fast if it's sitting. I left it unplugged when I went out of town for 10 days and came back to a nearly dead truck. It depletes at around 4-8% per day even when parked in the garage and not in active use.
  - kybernetikos 3y ago
    That seems wrong, might be worth getting it checked. (I have an EV but not a rivian)
    - metadat 3y ago
      The technicians say it's working as intended, maybe I have a setting wrong? I'm sure it's doing ..something.. Shrug
      - jeffrallen 3y ago
        Tell them there is NO WAY that is normal. I have left my Renault Zoe for a month and a half with a few percent loss. You have a warranty issue. Get it fixed before it's too late.
        metadat 3y ago
        A Renault is kinda irrelevant, I have both a Rivian R1T and R1S. They both behave the same. It's really up to the manufacturer how active they want the system to be when it's sitting in park. I'm sure they could improve it, but as another poster mentioned, maybe it's in a sentry mode or similar. I have an e-bike that I almost never plug in and it holds its charge just fine with almost no depletion after several months of sitting. Your mileage will vary :)
whatever1 3y ago
When they do though then you are stuck with a brick. In the US there is a federal mandated warranty of 100k miles. But this leaves the used market in limbo (one of the reasons that EVs have horrible residual value). If the failure rates are indeed so low then where are the insurance products for extended battery warranties? If the numbers are correct it would be a ludicrous business.
- ZeroGravitas 3y ago
  These products exist. Why do you think they don't? It's a fairly obvious outgrowth of similar extended warranty products for ICE cars, where people would also be stuck with a brick if a major component failed. A more interesting question is whether the prices reflect this science. Insurance are usually pretty good at this as it's their job, but in small markets they might play it safe.
- DanielHB 3y ago
  I work in the industry and from what I see the "bad" batteries are usually manufacturing problems and they stop working very early in their lifecycle. The degradation of charge capacity though is almost always completely dependent on usage patterns though, if you trickle-charge instead of fast-charge, don't do a lot of full cycles (100% to empty) and keep them in reasonable temperatures they will lose very little charge capacity. BMS systems in cars have been getting better and regulating the temperature of the batteries even when the car is off though. Unfortunately the used market doesn't have a reasonable way to measure charge capacity, the only way out is for regulations to force disclosure of current charge capacity and total power cycled through the battery and tools to get that information out. Those two metrics would provide similar information compared to mileage for a gas-powered car. Also if I had the capital, space and know-how I would be buying every single dirty-cheap used EV I could get my hands on and store the batteries. Soon those batteries are going to be a gold mine for recycling. Recycling li-ion batteries is like aluminium recycling, very energy intensive but you get almost all the raw materials back and recycled aluminium is cheaper than newly mined aluminium. Soon you will see people shipping those used batteries to places with cheap energy for recycling (like Iceland for aluminium recycling). The process is more complicated than aluminium and there aren't that many spent batteries around which is why this is not a big thing yet.
jeffrallen 3y ago
Another data point: the startups Renault was funding to reuse old vehicle batteries in stationary applications once they went below 85% capacity were starved of batteries to use, because the Renault battery packs last so long. They had to pivot to recycling tool batteries by shredding them! Source: I have a 6 year old Renault Zoe with more than 95% of it's original capacity. The only thing that's wearing out is the suspension and interior. The battery will outlast 3 chassis at this rate, it it was possible to transfer it to a new car.
erictd 3y ago
Since there are zillions of Model Ys out there, what will the replacement battery market look like when mine finally fails in n more years? Will there be relatively inexpensive batteries with the same kWh as mine? Will there be more expensive batteries with more or much more storage available? I guess I'll find out.
- theshrike79 3y ago
  There's already a secondhand market that replaces and upgrades Nissan Leaf batteries. Same goes for Teslas. The official Tesla service will always replace the whole slab for massive $$$$. Smaller independent shops (mostly self-taught currently) can replace individual failed blocks from donor batteries pretty cheaply. (Less money than an head gasket change or a clutch replacement.)

60 points by bilsbie 3y ago

I fully expect my 2017 EV to last for 15 years without significant degradation[1]. I see the usability of EV batteries like Solar panels - in about 10 years, they get to at worst 90% range, and are probably usable well into 20+ years. Battery tech is what makes our present and future tech economy possible [2]. [1] I don't baby my EV - always charge to 100%, use fast chargers, don't worry about getting it to 10% or lower. It has lost maybe 5% of it's rated capacity. [2] with apologies to CEO Morgan from SMAC.

dainiusse 3y ago
That is unrealistic expectation for 15 years, especially for a 2017 EV.
- treffer 3y ago
  Is it? The article lists 2015 as the year where things improved a lot, 2017 is well past that. The numbers are low and even that's inflated due to recalls. I've seen >>10 year old laptops where the battery is still good enough to go from charger to charger. Just go to ebay and check out 2009 MacBooks. That's ~15 years now. I don't think this is unrealistic if you can live with the heavier degradation.
- aetch 3y ago
  15 years is completely realistic, I only started having problems with my 2007 Ford Escape Hybrid after 17 years of heavy use and 260k miles. Keep in mind that 2007 was when the 1st generation hybrids were just coming out, too, so technology is much better today. Don’t forget that there are other parts of a car that degrades as well with time. Eventually most well used cars will have an engine or powertrain issue if they even make it to 15 years to use without being totaled in an accident or simply sold second hand or misused.
  - fransje26 3y ago
    The 2007 Ford Escape Hybrids were using a lot of shared parts with the Toyota Prius, so the battery pack is definitely not Li-ion. The newer high-density Li-ion packs will not survive 15 years without loosing significant capacity, if they survive at all.
    - aetch 3y ago
      The escape hybrid had a nickel cadmium battery. I don’t see why a li-ion battery pack wouldn’t be usable for 15 years with good battery management. Both battery and ICE cars have reduced performance and range due to capacity/efficiency degradation so replacing and recycling a battery or engine at 15 years to restore performance is not unreasonable. No car, EV or ICE lasts forever. Likewise, most people want to upgrade to a newer flashier car before 15 years.
      - dainiusse 3y ago
        Because we have plenty of real life examples for cars that have a lot less age.
      - satiric 3y ago
        The battery chemistry is completely different; You can't assume similar characteristics.
      - fransje26 3y ago
        > I don’t see why a li-ion battery pack wouldn’t be usable for 15 years. For 2 reasons, primarily. First, Toyota chose nickel-cadmium batteries because of their higher charge-cycle life, at the cost of a much lower energy density (about half that of li-ion). Secondly, they designed their system so that the discharge rate and the discharge level of their battery pack stayed low, thereby maximizing the lifetime of their battery pack, at the cost, once more, of extra weight. So those two aspects combined mean that you can expect a much longer real-life usage of your battery pack before reduced performance becomes an issue. I fully agree that a battery pack replacement after 15 years could be considered reasonable (as long as the build quality of the rest of the car warrants it, which is not a given nowadays). But if the mean-time between replacement is around 5 years, then it becomes unreasonable.
- audunw 3y ago
  Our 8 year old 2015 Kia Soul EV is about 15% degraded (on the worst cell, which could be replaced individually btw). Battery degradation is generally fairly linear between 100% to 70% SoH. So I don’t see why I shouldn’t expect another 8 years on it. It depends on how much it is driven of course. The mileage is probably a bit below average on that one. I have a short commute to work. We did some road trips in it though. You gotta take into account that old EVs with small batteries will probably often be used as a second car, and so used less often. That’s the case for us since we got a newer bigger car as our family grew. We don’t take the Kia on road trips anymore and my wife takes the bus to work.

PaulKeeble 3y ago

The projection on most of these batteries life times now is 500k+ miles before they hit 80% of their capacity. The car around the battery will be falling to pieces before they reach that point. Its not like there weren't quite a lot of ICE lemon vehicles with engine and other problems that caused issues, its always been part of any industry and there will still be packs in the future that don't perform as they should for as long as they are meant to. EVs generally will require less maintenance as they are substantially simpler vehicles with less moving parts.

SV_BubbleTime 3y ago
I’m an automotive EE. This may be a rating you heard somewhere but the truth with practical real-world use is… debatable. If you run these in a lab, ok, maybe, according to someone trying to sell you batteries. If you run your vehicle at a spread of -20F to 120F, absolutely not. I can promise you that the vehicles we are working on go past 2032 and they’re all still ICE. These EVa are just not replacements for ICE. They make great supplements and town cars. It’s a marketing failure, and I’m not sure the pie in the sky “your car will fail before your battery” claim is helpful. I’m pretty sure the only people that would jump on that are EV owners, which I am, and don’t.
- LeFantome 3y ago
  Not sure what kind of EV you have. Ours goes over 150 km most weekdays, somewhere beteeen 20 km and 200 km on weekend days, and has taken the family on multiple 1000 km or more road trips now. My wife drives the EV most days. I cannot count the number of times I have been running late and had to stop to fill my gas guzzler up. It is freeway most of the way to work ( no gas stations ) and I have risked it more than once. The EV “tank” is full every morning so it never puts her through that. In practice, I have way more range anxiety in my ICE vehicle than my wife does in her EV. Supplements and town cars? If I could afford a new vehicle, my ICE vehicle would be the supplement.
  - dieselgate 3y ago
    You present a valid argument but I think comparing an EV being charged every morning to not always having a full fuel tank in an ICE, in the morning, is apples to oranges. From that perspective the EV has an advantage but it’s not a direct comparison.

dieselgate 3y ago

Cool study and great to see some data on this. The numbers seemed pretty good to start out with - lower single digit failure percentage - but then they get an order of magnitude more reliable to tenths of a percent failure. I’m mostly curious what happens when an EV has been neglected or left un running for long durations.

metadat 3y ago
The battery gets depleted in my rivian pretty fast if it's sitting. I left it unplugged when I went out of town for 10 days and came back to a nearly dead truck. It depletes at around 4-8% per day even when parked in the garage and not in active use.
- kybernetikos 3y ago
  That seems wrong, might be worth getting it checked. (I have an EV but not a rivian)
  - metadat 3y ago
    The technicians say it's working as intended, maybe I have a setting wrong? I'm sure it's doing ..something.. Shrug
    - jeffrallen 3y ago
      Tell them there is NO WAY that is normal. I have left my Renault Zoe for a month and a half with a few percent loss. You have a warranty issue. Get it fixed before it's too late.
      - metadat 3y ago
        A Renault is kinda irrelevant, I have both a Rivian R1T and R1S. They both behave the same. It's really up to the manufacturer how active they want the system to be when it's sitting in park. I'm sure they could improve it, but as another poster mentioned, maybe it's in a sentry mode or similar. I have an e-bike that I almost never plug in and it holds its charge just fine with almost no depletion after several months of sitting. Your mileage will vary :)

whatever1 3y ago

When they do though then you are stuck with a brick. In the US there is a federal mandated warranty of 100k miles. But this leaves the used market in limbo (one of the reasons that EVs have horrible residual value). If the failure rates are indeed so low then where are the insurance products for extended battery warranties? If the numbers are correct it would be a ludicrous business.

ZeroGravitas 3y ago
These products exist. Why do you think they don't? It's a fairly obvious outgrowth of similar extended warranty products for ICE cars, where people would also be stuck with a brick if a major component failed. A more interesting question is whether the prices reflect this science. Insurance are usually pretty good at this as it's their job, but in small markets they might play it safe.
DanielHB 3y ago
I work in the industry and from what I see the "bad" batteries are usually manufacturing problems and they stop working very early in their lifecycle. The degradation of charge capacity though is almost always completely dependent on usage patterns though, if you trickle-charge instead of fast-charge, don't do a lot of full cycles (100% to empty) and keep them in reasonable temperatures they will lose very little charge capacity. BMS systems in cars have been getting better and regulating the temperature of the batteries even when the car is off though. Unfortunately the used market doesn't have a reasonable way to measure charge capacity, the only way out is for regulations to force disclosure of current charge capacity and total power cycled through the battery and tools to get that information out. Those two metrics would provide similar information compared to mileage for a gas-powered car. Also if I had the capital, space and know-how I would be buying every single dirty-cheap used EV I could get my hands on and store the batteries. Soon those batteries are going to be a gold mine for recycling. Recycling li-ion batteries is like aluminium recycling, very energy intensive but you get almost all the raw materials back and recycled aluminium is cheaper than newly mined aluminium. Soon you will see people shipping those used batteries to places with cheap energy for recycling (like Iceland for aluminium recycling). The process is more complicated than aluminium and there aren't that many spent batteries around which is why this is not a big thing yet.

jeffrallen 3y ago

Another data point: the startups Renault was funding to reuse old vehicle batteries in stationary applications once they went below 85% capacity were starved of batteries to use, because the Renault battery packs last so long. They had to pivot to recycling tool batteries by shredding them! Source: I have a 6 year old Renault Zoe with more than 95% of it's original capacity. The only thing that's wearing out is the suspension and interior. The battery will outlast 3 chassis at this rate, it it was possible to transfer it to a new car.

erictd 3y ago

Since there are zillions of Model Ys out there, what will the replacement battery market look like when mine finally fails in n more years? Will there be relatively inexpensive batteries with the same kWh as mine? Will there be more expensive batteries with more or much more storage available? I guess I'll find out.

theshrike79 3y ago
There's already a secondhand market that replaces and upgrades Nissan Leaf batteries. Same goes for Teslas. The official Tesla service will always replace the whole slab for massive $$$$. Smaller independent shops (mostly self-taught currently) can replace individual failed blocks from donor batteries pretty cheaply. (Less money than an head gasket change or a clutch replacement.)