Lithium battery degradation over years
- Thread starter Vikas
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The batteries on most cars don't completely charge or discharge which is why they last longer than one in your phone. It's also why Tesla and others can warranty them for 10 years or 150,000 miles (mandatory in 15 states now).
I'm sorry, what the internet doesn't need is unsubstantiated conjecture about how hybrid/electric car batteries don't last... it's been over a decade since the Prius/Insight came out. Battery life hasn't been a major issue. Get over it. There are plenty of reasons not to buy one (ROI, performance, hassle of charging) but this isn't one of them.
I'm sorry, what the internet doesn't need is unsubstantiated conjecture about how hybrid/electric car batteries don't last... it's been over a decade since the Prius/Insight came out. Battery life hasn't been a major issue. Get over it. There are plenty of reasons not to buy one (ROI, performance, hassle of charging) but this isn't one of them.
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Originally Posted By: bepperb
The batteries on most cars don't completely charge or discharge which is why they last longer than one in your phone. It's also why Tesla and others can warranty them for 10 years or 150,000 miles (mandatory in 15 states now).
I'm sorry, what the internet doesn't need is unsubstantiated conjecture about how hybrid/electric car batteries don't last... it's been over a decade since the Prius/Insight came out. Battery life hasn't been a major issue. Get over it. There are plenty of reasons not to buy one (ROI, performance, hassle of charging) but this isn't one of them.
Quoted for truth.
This thread sucks.
The batteries on most cars don't completely charge or discharge which is why they last longer than one in your phone. It's also why Tesla and others can warranty them for 10 years or 150,000 miles (mandatory in 15 states now).
I'm sorry, what the internet doesn't need is unsubstantiated conjecture about how hybrid/electric car batteries don't last... it's been over a decade since the Prius/Insight came out. Battery life hasn't been a major issue. Get over it. There are plenty of reasons not to buy one (ROI, performance, hassle of charging) but this isn't one of them.
Quoted for truth.
This thread sucks.
True that there is a lot of false, incomplete, and misleading information available on the internet - much of which many take as gospel.
I did note, however, that very recently a highly-regarded consumer research organization that uses surveys and statistical analysis did publish that, in their findings, the Honda hybrid batteries have a high failure rate - some 100X the Toyota Prius in the first few years. This was on battery packs that were 3-5 years old. The trend seems to continue. The Toyota prius, based on their surveys and statistical analysis, shows a very low failure rate even at 10 years.
I did note, however, that very recently a highly-regarded consumer research organization that uses surveys and statistical analysis did publish that, in their findings, the Honda hybrid batteries have a high failure rate - some 100X the Toyota Prius in the first few years. This was on battery packs that were 3-5 years old. The trend seems to continue. The Toyota prius, based on their surveys and statistical analysis, shows a very low failure rate even at 10 years.
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Yes, the longer you want your battery pack to last, the more conservatively you design it. Deep discharges are what kills batteries. When the state of charge gets down to 30%, it's time to call it "empty" and require a recharge. Also, don't try to charge the battery too quickly, or discharge it too quickly either. I-squared * R heating of the circuits reduces efficiency. And if you want good performance in winter weather, better park the car inside and keep the battery warm. Also don't let the battery or power control electronics get hotter than ~140F, or their efficiency drops due to higher electrical resistivity.
Did I miss any of the normal complaints about batteries?
Did I miss any of the normal complaints about batteries?
I knew that slow-charging was best and that quick charging was bad - but I was unaware that you do not want to drain it below 30%. hmm... no "memory effect" problems with lithium polymer or whatever they are?
30 Mile Honda Fit EVs get down to single digits pretty quickly too ...
Slow charging is not good for lithium ion batteries. Each manufacturing sets are preferred charging rate for their 18650s.
It is very true that they degrade over cycles it's proven by hobby chargers that measure capacity.
Capacity retention has come a long way though such as well Panasonic cells. Here is a data sheet of one of the most popular high quality 18650 on the market.
http://industrial.panasonic.com/www-data/pdf2/ACA4000/ACA4000CE254.pdf
You can see the capacity is still 2500 mAh out of 3100 after 300 full cycles. Partial cycles don't have the same effect on capacity.
It is very true that they degrade over cycles it's proven by hobby chargers that measure capacity.
Capacity retention has come a long way though such as well Panasonic cells. Here is a data sheet of one of the most popular high quality 18650 on the market.
http://industrial.panasonic.com/www-data/pdf2/ACA4000/ACA4000CE254.pdf
You can see the capacity is still 2500 mAh out of 3100 after 300 full cycles. Partial cycles don't have the same effect on capacity.
JHZR2
Staff member
Slow charging is better because it reduces the over potentials and thermal issues. All batteries have calendar life associated with chemical aging that is temperature dependent.
Capacity fade and impedance growth are linked but not necessarily the same phenomena. Certain LI-ion chemistries are more probe to aging than others.
Many Chibese 18650 cells are absolute junk too.
Capacity fade and impedance growth are linked but not necessarily the same phenomena. Certain LI-ion chemistries are more probe to aging than others.
Many Chibese 18650 cells are absolute junk too.
Charging at 0.18 C is a good idea because the cell is virtually full at 4.20v but higher currents will get the cell to 4.20 v quickly but capacity will still be low until constant voltage is applied and current drops to the determined rate. This is of course if you have a good cc cv charge.
I just don't want to confuse battery new comers who confuse slow charging with trickle charging which is a big no no with lithium ion cells.
There's not enough time for me to discuss how many garbage Chinese cells are on the market. I've seen tiny button cells soldered inside 18650 shells filled with plaster, also even RCR123 cells too inside the same shell. Amsoil used laptop cells without protection circuits even when claiming to have one. Buyer beware big time with 18650, stick to name brands. Panasonic, Eagletac, AW, Callies Kustoms, Orbtronic to name a few.
Back on topic though... Just don't keep the car after the 10 year battery warranty is up and you're golden. Unless of course you can afford a new pack out of pocket, then by all means run it into the ground and see how long it lasts.
I just don't want to confuse battery new comers who confuse slow charging with trickle charging which is a big no no with lithium ion cells.
There's not enough time for me to discuss how many garbage Chinese cells are on the market. I've seen tiny button cells soldered inside 18650 shells filled with plaster, also even RCR123 cells too inside the same shell. Amsoil used laptop cells without protection circuits even when claiming to have one. Buyer beware big time with 18650, stick to name brands. Panasonic, Eagletac, AW, Callies Kustoms, Orbtronic to name a few.
Back on topic though... Just don't keep the car after the 10 year battery warranty is up and you're golden. Unless of course you can afford a new pack out of pocket, then by all means run it into the ground and see how long it lasts.
A properly managed, thermally controlled, carefully produced battery pack cannot be compared to the performance of Chinese hobby lithium batteries.
The R+D involved in the Tesla Model S battery pack was substantial.
Yes, I understand some Tesla roadsters were driven to battery exhaustion, then parked for extended periods of time without charging. Leading to a "Bricked" battery. This is a real risk that must be managed. For example, the cars can now alert you and Tesla that the state of charge is below 5%. There are other management solutions also. So far, the Model S has done well with regard to this.
The R+D involved in the Tesla Model S battery pack was substantial.
Yes, I understand some Tesla roadsters were driven to battery exhaustion, then parked for extended periods of time without charging. Leading to a "Bricked" battery. This is a real risk that must be managed. For example, the cars can now alert you and Tesla that the state of charge is below 5%. There are other management solutions also. So far, the Model S has done well with regard to this.
Prius and Lithium have nothing to do with each other.
I got that chart from our vendor who is going to supply us a battery back up power supply for our next generation product. These are built from Sony Li(NiMnCo)O2 12x18650 3S4P package. I am assuming these guys know what they are shipping us. That chart really surprised me. The operational life of this pack is going to 5 years and we are designing so that these can be replaced in field.
I am wondering if NiMh have better life span than Lithium. Prius has stellar battery reputation.
I got that chart from our vendor who is going to supply us a battery back up power supply for our next generation product. These are built from Sony Li(NiMnCo)O2 12x18650 3S4P package. I am assuming these guys know what they are shipping us. That chart really surprised me. The operational life of this pack is going to 5 years and we are designing so that these can be replaced in field.
I am wondering if NiMh have better life span than Lithium. Prius has stellar battery reputation.
JHZR2
Staff member
What is the temperature assumption for that degradation rate? Rates of operation?
The high-voltage operation of NCM (>4.3 V) required for high capacity can cause more rapid loss over numerous cycles. The surface lattice structures of NCM can undergo transformation, especially under charge conditions, with surface changes fom a rhombohedral phase to spinel and rock salt phases. High voltage, top of charge conditions, which are necessary for maximum energy density create a highly oxidative environment and is bad for the electrolyte and the materials of the cathode. This you create insulating phases and a larger SEI, which results in impedance-based voltage drop and sluggish kinetics.
The high-voltage operation of NCM (>4.3 V) required for high capacity can cause more rapid loss over numerous cycles. The surface lattice structures of NCM can undergo transformation, especially under charge conditions, with surface changes fom a rhombohedral phase to spinel and rock salt phases. High voltage, top of charge conditions, which are necessary for maximum energy density create a highly oxidative environment and is bad for the electrolyte and the materials of the cathode. This you create insulating phases and a larger SEI, which results in impedance-based voltage drop and sluggish kinetics.
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