from the making-better-use-of-what-you've-got dept.
Predicting the slow death of lithium-ion batteries:
Batteries fade as they age, slowly losing power and storage capacity.
[...] Now, a model developed by scientists at Stanford University offers a way to predict the true condition of a rechargeable battery in real-time. The new algorithm combines sensor data with computer modeling of the physical processes that degrade lithium-ion battery cells to predict the battery’s remaining storage capacity and charge level.
“We have exploited electrochemical parameters that have never been used before for estimation purposes,” said Simona Onori, assistant professor of energy resources engineering in Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth). The research appears Sept. 11 in the journal IEEE Transactions on Control Systems Technology.
The new approach could help pave the way for smaller battery packs and greater driving range in electric vehicles. Automakers today build in spare capacity in anticipation of some unknown amount of fading, which adds extra cost and materials, including some that are scarce or toxic. Better estimates of a battery’s actual capacity will enable a smaller buffer.
“With our model, it’s still important to be careful about how we are using the battery system,” Onori explained. “But if you have more certainty around how much energy your battery can hold throughout its entire lifecycle, then you can use more of that capacity. Our system reveals where the edges are, so batteries can be operated with more precision.”
The accuracy of the predictions in this model – within 2 percent of actual battery life as gathered from experiments, according to the paper – could also make it easier and cheaper to put old electric car batteries to work storing energy for the power grid. “As it is now, batteries retired from electric cars will vary widely in their quality and performance,” Onori said. “There has been no reliable and efficient method to standardize, test or certify them in a way that makes them competitive with new batteries custom-built for stationary storage.”
Not just car batteries — I'd like to know if it could be applied to cell phones, tablets, and laptops.
Journal Reference:
Anirudh Allam, Simona Onori. Online Capacity Estimation for Lithium-Ion Battery Cells via an Electrochemical Model-Based Adaptive Interconnected Observer, IEEE Transactions on Control Systems Technology (DOI: 10.1109/TCST.2020.3017566)
(Score: 2) by looorg on Tuesday September 15 2020, @06:39PM (7 children)
Just curious but how much of the battery capacity is drained to check how much battery capacity/life there is left?
(Score: 1, Insightful) by Anonymous Coward on Tuesday September 15 2020, @07:23PM
enough to force, er, encourage you to buy a new phone?
(Score: 2, Informative) by nostyle on Tuesday September 15 2020, @07:38PM (4 children)
The voltage level of the battery generally indicates the charge status of the battery, and measuring that voltage can be accomplished with virtually no drain on the battery.
The "life" or charge capacity of a battery is a different thing and it degrades over the sequence of charge cycles. To track this degradation one would probably want to keep a historical record of charge/discharge cycles. As to how much that will drain the battery, it would depend on what sort of computer you were running and what software was keeping/analyzing that history.
(Score: 1) by CloudStroller on Wednesday September 16 2020, @01:21AM (3 children)
As far as I understand, for lithium batteries this is not true. They have (fairly) constant voltage profiles until they are fairly drained. Advanced battery monitors do some kind of coulomb-counting.
(Score: 0) by Anonymous Coward on Wednesday September 16 2020, @02:44AM
That would explain all the fires. It turns out that lithium batteries do not "balance" the cells well on charging, and it is over-voltage of an individual cell which causes catastrophic failure.
(Score: 2) by fakefuck39 on Wednesday September 16 2020, @02:45AM
da fuq you talking about. they do not have constant voltage profiles. they charge up to 4.2V at full (which is actually like 90% charge) and go down to 3.3 when they say empty (which is actually like 10% charge left). "advanced" battery monitors look at the voltage and tell you the capacity.
(Score: 2) by sjames on Wednesday September 16 2020, @02:17PM
You're thinking of NiCd and NiMH. Those maintain a nearly constant 1.2V then fall off a cliff right at the end of the discharge cycle.
LiIon batteries have a more steady voltage decline through the cycle. The difficulty with them is that they experience more wear at the extremes of their charge state, so there is always a tradeoff between capacity and lifetime. If you see a sudden cutoff, that's a protection circuit to avoid over-discharge. That's quite common as an over-discharged LiIon battery is effectively dead and attempting to recharge it can be quite "exciting".
(Score: 2) by DeathMonkey on Tuesday September 15 2020, @08:00PM
You're already doing that monitoring, though, to populate that battery gauge at the top of the screen.
I would doubt that preserving that data causes much more battery drain.
(Score: 2) by JoeMerchant on Tuesday September 15 2020, @07:02PM
These models are going to be developed, at great expense and effort, for a particular production process and then applied to as many production lines as possible.
Beware when your "super value" batteries use this same model, but have "economized" the process in one or more ways which invalidates the model, and instead of getting 2% more life from your battery due to the excellent fitting of the model to the physical device, you experience a 20% or more loss of battery life (and/or hazardous conditions) due to the model allowing your "super value" batteries to operate in.... less than optimal states.
🌻🌻 [google.com]
(Score: 3, Interesting) by MIRV888 on Tuesday September 15 2020, @07:29PM (4 children)
Relative to other lithium-ion bats I have in various devices, drone batteries die fast. Never more than a year and they are shot. I gather it's the high discharge rates. Motors pull a lot of load very quickly. I would love to have a means by which to know the batteries actual flight time / discharge capacity. Because when they go, it can be quickly. That is not good while airborne.
(Score: 2) by JoeMerchant on Tuesday September 15 2020, @07:46PM (2 children)
Puffy batteries are your first clue... if you are in a safety critical application: puffed batteries are done.
🌻🌻 [google.com]
(Score: 1) by MIRV888 on Tuesday September 15 2020, @07:57PM (1 child)
For sure, but even unpuffed they reach an end of service life that isn't always obvious. I generally toss them when I am at about 75% of original flight time. That's never more than a year for me. I fly about once a week.
(Score: 5, Informative) by JoeMerchant on Tuesday September 15 2020, @08:51PM
I worked at a fixed wing drone design/manufacturer. They designed custom LiPo packs, nothing exotic, just a pack of rectangular cells each maybe 0.5cm thick. Our flight crew had a pretty religious battery maintenance routine and they could get 100+ flights out of a pack, but... the drone had a 60 minute advertised flight time, which it could do, but only barely and when you'd push it to get 60 minutes those packs might last 5 flights tops. That flight time was also very dependent on thermals - 60 minutes was doable in still air, but if the conditions were "sinking air" you'd have to really torture the battery pack to get 60 minutes. For the 100+ flights routine, they'd be setting up for landing around 45 minutes, max.
🌻🌻 [google.com]
(Score: 2) by fakefuck39 on Wednesday September 16 2020, @02:53AM
FYI - lesson I learned from vaping. Get a lower amp-hour rated battery with a higher max draw, and it'll not only last longer per charge, it'll last more charges. I now get ones with double the amps I need, even though it's lower capacity.
also, order from a battery store and get a good brand like panasonic. it's literally all fake on amazon - I compare to official spec weight of models and it doesn't match - tried several times.
(Score: 5, Interesting) by drussell on Tuesday September 15 2020, @07:45PM (1 child)
Oh, great.... So now they'll be able to do an even more severe job of building things down to a price....
When they engineer out that "excess" cost, they tend to also engineer out every last remaining drop of decent quality.
I'm all for more accurate guesstimates of remaining battery capacity / cycle life, but that's not what this will be used for.
(Score: 1, Touché) by Anonymous Coward on Tuesday September 15 2020, @08:16PM
This reminds me of the CAD tools that can calculate material strength easily and precisely. My most hated application of that tool is when they use it to design reinforcing ribs into a paper thin piece of plastic that is hollow underneath (where the ribs go) so that they get away with the least amount of plastic possible. The plastic flxes and creaks in use and eventually shatters. All to save a fraction of a penny in plastic.
Here's to lithium ion battery packs that wear out quicker!
(Score: 2) by Mojibake Tengu on Tuesday September 15 2020, @10:13PM
Can I have β-decay microreactors instead yet?
Something like this one:
https://phys.org/news/2018-06-prototype-nuclear-battery-power.html [phys.org]
Respect Authorities. Know your social status. Woke responsibly.
(Score: 0) by Anonymous Coward on Wednesday September 16 2020, @12:22AM (2 children)
Heard all kinds of conflicting stuff like
never/always discharge to 0%
Never/always recharge to 100%
Don’t store at a charge level of x%
(Score: 3, Interesting) by CloudStroller on Wednesday September 16 2020, @01:24AM (1 child)
Conflicting advice is usually for different chemistries. Always discharge to 0% - older NiCad batteries. Never recharge to 100% - newer Lithium, though some reckon that manufacturers re-calibrate their battery gauges so that when your phone says 100% then it's actually a bit lower. I don't believe this myself, so I tend to charge to 80% or so.
(Score: 0) by Anonymous Coward on Wednesday September 16 2020, @04:34AM
And let go. Move on with your life.
(Score: 1) by Coligny on Wednesday September 16 2020, @03:40AM
"Better estimates of a battery’s actual capacity will
enable a smaller buffer"
Sure, they really do need more excuses to make even worse quality...
Thank again to the "but... the algorythm..." mantra.
If I wanted to be moderated by mor0nic groupthinking retards I would still be on Digg and Reddshit.