Well done. Thank you! People not interested in the technicalities should skip to 19:40 - knowing that the reasoning for this guidance is explained in terrific technical detail in the previous portion of the video.
What this video taught me is that either there will be decades of small changes that will fix and improve each individual piece of this problem, or that there needs to be a radical change in chemical and structural design of batteries in order to eliminate these issues. This was a very in depth discussion, and I'm glad to have seen just how difficult and complex this problem is, and I'm also glad you included ways that the average person could improve the longevity of their batteries with the explanation.
this is such an amazing video that i paused and wrote every word you said! you know what you are talking about so well and it shows (unlike other youtubers where they clearly researched the topic for 2 hours before making a video). thank you so much coming from a PhD student specialized in solid-state electrolytes
"If you have managed to reach the end of this video" lol. This video is brilliant. There are plenty of videos explaining what to do and what not to do when it comes to EV use and charging. Nothing comes close to this video in terms of explaining why.
I wish I could give this 10 thumbs up. Best comprehensive description of lithium-ion battery degradation that I've ever seen. I worked in the battery industry and I know batteries VERY well, and this video taught me a few things I didn't know. Well done!
It is astounding, and a revealing insight into the sad state of online information sharing, that only a few hundred people have "liked" this excellent video in the almost three years that it has been posted.
Here's a few interesting questions regarding phones: 1) Do these same basic principles apply to Li-Po batteries? 2) Does using your phone while charging make any difference as opposed to running on battery? Would it be beneficial to do so? 3) Is wireless charging (which is naturally slower than wall plugs) potentially more damaging since it supposedly generates more heat? Or does the slower rate make it a safer alternative? 4) And lastly - can phone batteries be preserved for much longer by applying the same tactics to prolong life due to slower charging rates and less time directly under sunlight than electric vehicles? ---- My Galaxy s6's battery (5 years old) is in the valley of doom at this point lasting a whopping 25 minutes. It takes that long to go from 100% - 70% at which point it dies. I did not apply any of these tactics in the past to preserve it's life and greedy companies don't let us replace the battery easily. So now I'm going for the Note 20 Ultra and so I really want to know if I can get that thing to last the next 5 years even better! Let me know pls, thanks 😎
Very nice. It would be very helpful to add a circle or something over whatever it is you currently talking about so that it's easy to follow for someone who isn't very familiar with the layout of the materials/structure.
Very nice explanation of degradation mechanism in an clear exhaustive way. Just one comment: for the NMC or NCA batteries, its better to store at SOC100 rather than SOC70 to SOC80. Since keeping the cell at SOC70~SOC80 degrades worse than SOC100. This is a spoon shape and can be explained by the non-monotonic anisotropic stress accumulation(ASA) due to special M-H2-H3 phase transformation of Ni-rich lattice. When the battery is at approximately 70% SOC, it enters M-H2 phase transition region and experiences maximal ASA, which leads to the most severe structure degradation and the lowest capacity retention. Its quite an Anomalous calendar aging behaviour of Ni-rich cathode batteries. Overall, nice video and keep it up!!!!!!
What a master lesson, and how well explained. Congrats and thank you! Question: you mention that Anode volume increases about 13% for NCM and NCA. With that, can we say that the Cathode volume decreases 13% as well?
No, the volume changes in the cathode are far less radical. I don't know if it's because it has more stable voids, or if there's just more cathode material per unit of lithium. It might be a combination of both. Silicon anodes can store far more lithium than graphite, but they expand and contract even more, which is a big challenge.
There's a kind of positive feedback situation in their use as well. Useable capacity is high charge - low charge, but as your battery degrades you will need to push this to a higher high charge and a lower low charge for the same energy, but this accelerates the degradation.
Depth of discharge is a parameter that drivers have some control of. For example, I can choose to charge once per day, adding 60% SoC, or twice per, 30% a time. While it's clear that the shorter charges are preferable, can you comment about whether what's worse for the battery, idle time at 100%, or larger depth of discharge?
Excellent overview. I knew about dendrite formation, but learned even more. Thx! Pack calibration aside... What about maintaining SoC at or near 50%? Better still? Particularly for long term storage/vacation? And better to leave unplugged when charging is not needed?
Thank you for this video! Very informative, as usual. You should make more of these but of course I'm the consumer here and I have no idea how much time you pour into each video, so I won't bug you any further :p Also, you corrected one of my long time mistakes: I thought the I in SEI stood for Interface...
Excellent video! You mentioned trying to avoid fast charging when battery is hot. In the case of 2170 Tesla cells, what is considered hot? The common knowledge of owners seems to be that Supercharging will occur quicker if you "drive faster / highway speeds" just before charging. Is this a bad idea for longevity even though supercharging may actually take less time when hot?
Awesome video. I've just purchased a model 3 and i have a question. I dont have acces to a charger at home yet and use one at my friends hosue every 2 or 3 days. For the battery health is it better to charge everyday and top the battery up to 85%? Or if i stay in the range of between 25% - 85% i can charge my car every 2-3 days? Love your content.
What role does a "buffer" play in degradation? For example, Fords Mach E smaller batter is 76kwh but has a usable 68kwh, and the larger battery has a 99kwh capacity but is limited to 88 usable. I suppose this is about a 10% buffer. Thank you if you get a chance to answer. Some of this was a bit over my head but I'm interested in learning. I would also be interested in how a buffer is implemented exactly? At the top end, low end or somehow a bit of each.
I really wished more people would watch this before championing for EVs. Also, most batteries might not have enough usable range after 10 years due to all these factors.
Yes, the usable life of an EV battery is much shorter than the expected life of a vehicle, so - unlike vehicles with engines - replacement of this major component should be expected once in the life of the vehicle. That's okay, if it considered in the cost and environmental consequences of the vehicle choice. One city (Edmonton, Canada) that recently started adding battery-electric buses to its fleet budgeted for complete battery replacement at 12 years, and was provided with a 12-year battery warranty from the bus manufacturer.
Most EVs come with a 10 year warranty on the battery. The average car ownership in the US is 6 years. Although there are plenty of people who keep cars for 10-20 years, this is not necessary common. EVs in their current state are perfectly fine for 85% of people. I have a 2012 Nissan Leaf with only 15% battery degradation and the Leaf doesn’t even have thermal management. There are plenty of Tesla Model 3s and Chevy Bolts who only experience 5% degradation after 100,000 miles. So it’s rare for a battery to degrade past the point of usable during ownership. People also confuse degradation with function. Most EV batteries are manufactured to function for 300-500k miles. So it’s also a rarity that a battery will ever just stop working during the ownership of one.
Very interesting. So when a particular Auto maker provides an estimated battery range/life. Have they taken into account all these degradation processes? And if so how accurate can be their estimations understating the difficulty in which simultaneous chemical processes can affect progressive resistance and battery life.
A recent Fully Charged video showed a battery powered ferry that tops-up after every short crossing. They keep the battery within 40% and 66% Accubattery shows 40-66% is just 5% of a cycle wear for this 26% depth of discharge (calendar wear should also be reduced at this lower charge state) 26% of 300 miles is 78 miles -- if the car can cope with repeated shallow cycling and not charging above 66%? 26% or 80 kWh is 21 kWh, so a charger would top-up in about Constant 7kW charge: 21/7 = 3 h Constant 50kW charge: 21/50 = 0.42 h = 25 mins
Staying within a narrow SoC window will help to reduce degradation, primarily because mechanical stress and number of electrode structural changes is reduced. The precise optimum SoC will differ for different battery chemistries and electrode designs.
So I just got my Tesla and I'm curious say I run to the store and use only like 15 miles or so. Should I plug in my Tesla and recharge it to 90% or just wait untill the end of the day and then charge.
Congratulations! If you don't need the range, don't plug it in. I tend to charge to 85% on weekdays for my commute, and leave at 60% at the weekend unless I'm going on a trip. Now that we're on lock down, I've left it unplugged at about 50 % soc.
Hi. Watched all Tesla videos and this one. Awesome work. Too bad you are not a regular content creator. Tesla claims 8 years warranty on their batteries I read. Some websites say that even if you don't use the batteries, just enough to keep them at a nice (storage) voltage in 3 years they will have to be renewed. I suppose batteries are better now. But looking after your batteries like charging them only to to 3.92V and never deepcycling them and after 5 to 10 years, if your $10K-20K battery turns out to be nothing but paper weight, it will be devastating. You won't save enough from the fuel to make up for that kind of cost. People don't talk about that.
Thanks, I make as many as I can. Tesla have proved that their batteries should last for over 8 years, by having cars in the field for more than 8 years. Realistically, you'll should be concerned about battery life when the vehicle is 12-15 years old...
@@EVTechExplained would you be able to say the same thing about other brand name batteries like Samsung or LG? If I invest in them and say use them only 4 months a year. Do you think they'll last 12-15 years?
@@EVTechExplained NMC or otherwise(chemistry agnostic)? They do have different cycling performance. I wonder if their cycling performance correlates to their life span performance. Thanks a lot for responses.
I wonder if there are battery limiters available for EVs? For small devices like iPhones, battery limiters like Chargie can be used. I use it personally to limit my charging to 80% and possibly maximize my lithium-ion battery life. But I wonder if there is a similar device for full-blown Electric Vehicles.
It becomes further complicated when considering the correlations between the root causes (16:00). For example, the charging power (high current on the chart) will impact the battery temperature. Also depth of discharge (DOD) is another factor often considered to be effective which could be defined as the difference between the state of charges before and after discharging (through normal usage or V2G service). Moreover, in theory, energy cycles is also a parameter which could be controlled by EV chargers. It just depends on whether or not the EV charger considers the charge/discharge cycles in their operation algorithms.
Sorry for a silly question, but what is the correspondence between anode/cathode and positive/negative terminals of the cell? Anode and cathode refer to current flow direction, so they reverse depending on if the cell is being charged or discharged. What process do anode/cathode in this video refer to: charging or discharging? that's why i don't understand the correspondence. Positive and negative terminals never reverse under normal operation, and so it is a better name, imo... Oh, and thanks for this in-depth video, very interesting.
found the answer. 9:12 "during charge, [positive] lithium ions are transferred from the cathode to the anode" So, cathode is the positive terminal, anode is the negative terminal.
If a battery loses 50% of it's capacity, how is the efficiency of the charge affected? In other words, how does energy in vs energy out change as a lithium battery degrades?
hi i have a query. i was checking an article from research gate where they say storing the battery at soc of 15% will cause 1-1.5% approx calendar ageing around 25 degree celcius .....but they also had battery vs FCE(full cycle equevalent) degredation graph where using a ev between 10-30% SOC causes the slowest degredation compared to 20-30% .. ..thus using below 15% SOC upto 10% infact is better than using between 15-25%...i am a bit confused... and i have been storing my battery around 10% SOC during calendear ageing as far as possible...so if its detrimental then i will keep SOC around 15-20%..thank you so much .. the battery used in my ev sccooty is typical NMC battery from manufacture phyllion 48V 28AH
Awesome! One question, for daily usage on a Tesla P100D, would it be better to - Keep in the 75% to 35% SoC range, resulting in some short high current discharges (pedal to the metal!), for example, 5C for a few seconds at 40% SoC, or - Keep a higher cycle like 85% to 45%, so that those short high power discharges occur at a higher average SoC? What I'm really asking is what's better: to have an average SoC of 55%, or to have an average SoC of 65%.... both taking into consideration the existance of short high power discharges? Probably the right answer is: to a 75% to 35% cycle, but only floor it if the SoC is > 50%, or so.
Not an engineer, but those both seem to be within the healthy SoC range, and the graph at 11:15 shows mostly linear potential voltage within the stability window. I know this doesn't address high current discharge directly, but being within the recommended range shouldn't change for a few seconds of high discharge. I would say the 85%-45% is safer from not dipping into a low SoC and of course remember to let your battery cool down before charging!
I have made my model 3 for about 1 year. About twice I have ran the battery down to 5% and immediately plugged it in afterwards. Is the problem with a low state of charge (e.g.
One problem is electrode stress related from going to very low soc, and the other is related to storage at very close to zero. Occasionally going to low soc is not problem. I've also had my Model 3 for about 1 year, and I also have gone down to 5% 2-3 times. If it is rare for you to do it, don't worry.
Thx I have question Like in present world situation because of covid all transportation in India stopped in this case ,If a lifepo4 battery pack has 1. Been charged charged for 100% and not used(discharged) for more than a month what happens to it. 2. Same case with 50% charge 3. Same case with 10% charge in battery Wat are disadvantages or nothing happens to it in all cases Does degradation takes place
What do you mean by avoid charging immediately after aggressive usage? You mean long high speed stretches? But isn't that what we do on Suc and isn't the battery preconditioning on Tesla what this is for? Also on my Model 3 I noticed that when I drive at lower speeds at about 90km/h the battery starts preconditioning 15 minutes early when I set Supercharger as a destination (Tesla feature), but it doesn't when I drive 150. This shows me that with 150 the battery is already around optimum temperature. Not sure if Tesla cools or just heats the battery for Supercharger. What are your thoughts?
Does batteries behave like living beings? Can swollen li-ion batteries damage car? What are fire hazard in ev ? What is the maintenance costs of EV vs fuel cars? What is the payback time for an ev
Hi would you please able to share the reference research articles based on your talk on the root causes of battery degradation and preventive measure. thanks. I will share my email address or you may kindly put the reference here. thanks
My brain is small. I need just concrete short recommendations how to degrade as much and as fast as possible the battery. I must reach in 2 years 74% now it's 88% and it's a f shame. Hopefully they'll give me a new battery these mfers. Sorry I'm really disappointed with my battery but i still love my car❤❤
In 7:30, the reduction of porosity size of the SEI as it thickens, makes it possible for Li+ to not fully dissolved. Question here, if the porosity size is smaller, wouldn't the pre-solved Li+ (before entering anode) been more cleanly "stripped", hence more fully disolved, AFTER they penetrate the SEI layer? Completely opposite logic here, I wish I made it clear here and hopefully anyone can shed some light on it?