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BU-808: How to Prolong Lithium-based Batteries (2023)

batteryuniversity.com

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Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#41

Post by user_7832 »

user_7832 wrote: post #13
SV_BubbleTime wrote: post #11

Earlier quoted context omitted.

> Do EV manufacturers use any other tricks not covered by this? Automotive EE here. EV aren’t ready for world wide use. That statement is constantly ignored by people in California who see zero issues with their new expensive fancy cars. Shortest version… The heating and cooling systems of the battery are there to prevent damage. BUT… who powers the heating and cooling systems? The battery of course. In a traditional…

> EV aren’t ready for world wide use. Fully agree (I'm 100% team PHEV or EREV/REEV) as a mechanical engineer. IMO BEVs and PHEVs/REEVs should be on parity in terms of tax/govt incentives, while encouraging electric use - for eg, subsidized (PH)EV charging, high(er) costs in city centres if running in ICE mode, etc. I was just curious if EV manufacturers use any other tricks that're "well known" in EV-land but not for…

I don't know why I'm being downvoted, but I live in a developing country where the tailpipe emissions from a modern well maintained car are literally cleaner than that of commercial (power) plants - potentially making EVs worse. Ofc I'm sure it's much nicer if you're in a 1st world country, but unfortunately that's not where I am.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#42

Post by user_7832 »

kanbankaren wrote: post #15
user_7832 wrote: post #13

Earlier quoted context omitted.

> EV aren’t ready for world wide use. Fully agree (I'm 100% team PHEV or EREV/REEV) as a mechanical engineer. IMO BEVs and PHEVs/REEVs should be on parity in terms of tax/govt incentives, while encouraging electric use - for eg, subsidized (PH)EV charging, high(er) costs in city centres if running in ICE mode, etc. I was just curious if EV manufacturers use any other tricks that're "well known" in EV-land but not for…

AFAIK, they charge only to 4.0 V. I think the batteries on satellites are also charged only to 4.0 V

Thanks! That's very helpful (and unsurprising) to know. Any idea if satellites use LTO batteries btw? They have much longer lives and apparently can tolerate much more abuse.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#43

Post by user_7832 »

simulator5g wrote: post #21
user_7832 wrote: post #13

Earlier quoted context omitted.

> EV aren’t ready for world wide use. Fully agree (I'm 100% team PHEV or EREV/REEV) as a mechanical engineer. IMO BEVs and PHEVs/REEVs should be on parity in terms of tax/govt incentives, while encouraging electric use - for eg, subsidized (PH)EV charging, high(er) costs in city centres if running in ICE mode, etc. I was just curious if EV manufacturers use any other tricks that're "well known" in EV-land but not for…

These acronyms are a nightmare, what the hell is a PHEV? EREV? PZEV? Consumers are just expected to know this stuff somehow, it’s nuts. Sometimes I buy parts for my car and just hope I selected the right one, because some models are PZEV/not PZEV but the sticker that would tell me has turned completely white & can’t be read.

> These acronyms are a nightmare, what the hell is a PHEV? EREV? PZEV?

PHEV is the old term, it's a plug in hybrid EV. I.e., you can plug it in and use the battery, or use the ICE engine via petrol (gasoline).

(B)EVs are pure battery EVs. Think Tesla.

REEV/EREV is range extender EV. Essentially an EV that has a small ICE engine that's very handy for making the 50 or 100km battery "run" for 500km if the need arises, by using the ICE as a generator.

In some countries, you also have "strong" and "weak" hybrids - these are not cars you can plug in (they only take petrol), but they use some motors and battery to vastly improve the efficiency of the engine. Think doubling your mileage levels of good.

> Consumers are just expected to know this stuff somehow, it’s nuts.

Yeah no I don't think that's good design either. May I ask what kind of parts do you buy that makes it so confusing? Our car (Honda) has a very simple model name, there's not a lot of variations or options to confuse to begin with.

Btw, if you want a real fun doozy, look up the parallel series hybrid system that iirc GM had. It was a beautiful beast - it could basically take any power source, and do anything with it (charge battery, run wheels etc). There's a good YouTube video on it if you search for it.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#44

Post by BLKNSLVR »

stavros wrote: post #9
BLKNSLVR wrote: post #5

Earlier quoted context omitted.

My charging solution is that I've purchased three (cheap and therefore slow) wireless charging docks that sit my phone slightly leaning backwards, therefore nicely viewable if necessary. One sits on my desk at work, one sits on my desk at home and the third sits on my bedside table (it acts like a clock radio / alarm clock). I just place it on the relevant charger while working / sleeping and it's always got enough c…

Those really make my phone overheat, so I avoid them. Didn't they heat yours up?

Sometimes the phone is warm, I wouldn't even say hot. Could be because I bought lower wattage wireless chargers - I don't need it to charge fast, I just need it to top up the battery.

The only time my phone has given me a message about heat was, indeed, in a phone holder in the car, but it wasn't even charging. We are experiencing a heat wave in Australia right now though, and the car had been sitting in the sun in a car park for an hour.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#45

Post by SV_BubbleTime »

s-y wrote: post #38
SV_BubbleTime wrote: post #11

Earlier quoted context omitted.

> Do EV manufacturers use any other tricks not covered by this? Automotive EE here. EV aren’t ready for world wide use. That statement is constantly ignored by people in California who see zero issues with their new expensive fancy cars. Shortest version… The heating and cooling systems of the battery are there to prevent damage. BUT… who powers the heating and cooling systems? The battery of course. In a traditional…

Are you a technician or an engineer? And as a follow up, what part of the vehicle do you engineer? Because this sounds a lot like a case of a dentist seeing a lot of cavities and making conclusions that teeth are "bad tech". I live in a climate that's in yearly flux from -20 to +35 C and EVs have been normal here for a long time(7+ years) with no major issues. What parameters and therefore regions does your statement…

Engineer. I started in core competency groups, worked on powertrain integration, and now, I’m a specialist. I roam around and put myself to use wherever needed. I’m now a consultant but I have badges for idk, maybe 20 facilities.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#46

Post by BLKNSLVR »

simulator5g wrote: post #22
stavros wrote: post #9

Earlier quoted context omitted.

Those really make my phone overheat, so I avoid them. Didn't they heat yours up?

They’re a joke, I used to have one in my car and the combination of sunlight & internally produced heat would make my phone shut off & display a “iPhone is too hot” message. Even when it’s cold outside.

Time for a new Vapor Cooled iphone?!

/s

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#47

Post by user_7832 »

pengaru wrote: post #26
SV_BubbleTime wrote: post #11

Earlier quoted context omitted.

> Do EV manufacturers use any other tricks not covered by this? Automotive EE here. EV aren’t ready for world wide use. That statement is constantly ignored by people in California who see zero issues with their new expensive fancy cars. Shortest version… The heating and cooling systems of the battery are there to prevent damage. BUT… who powers the heating and cooling systems? The battery of course. In a traditional…

How is this not an instance of "perfect is the enemy of good enough?"?

Honestly in this situation, hybrids (ideally of the plug in variant) are the "good enough" thing when you're shifting from ICE.

Shifting the easy 70% first gives a very nice boost, and the rest can be cajoled/fed hydrogen (if it matures by then) etc over time.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#48

Post by avidiax »

gruez wrote: post #40
avidiax wrote: post #37

I may be a bit odd, but I store lithium ion battery containing electronics in the vegetable drawer in the fridge. You lose 20% of capacity in a year if you have 100% state of charge but only 6% loss of capacity at refrigerator temperatures. So tool batteries, small electronics and whatever else that isn't used weekly gets put in. I also try to charge fully only just before use (and only if I need 100%), and store at…

>You lose 20% of capacity in a year if you have 100% state of charge but only 6% loss of capacity at refrigerator temperatures. Source? The common figure for smartphone batteries is " at least 80% capacity after 2 years", and that presumably includes cycles, not just leaving it charged.

From the article, Table 3: 100% SoC @ 25°C leaves only 80% of the original capacity after a year.

It's easy to look at that table and think that it's remaining charge after a year; it's not. It's lost capacity.

This is known in the industry as "calendar aging". So far as I know, stockpiles of lithium ion batteries are stored at a relatively low state of charge and in a cold environment for this reason among others. It's common to order a laptop battery or similar and get a unit that was manufactured a year back. It would be terrible to get a new battery that already had diminished capacity, which is what would happen if you stored them in a non-conditioned warehouse in a hot climate.

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#49

Post by averynicepen »

user_7832 wrote: post #6

+1 for battery university, they're an excellent source. Does anyone have any other suggestions for similarly technically deep (while approachable) articles on any other facet consumer electronics? My understanding from this article is that: 1. Charge the battery to as low a max percentage as possible (till about 65%) 2. Keep it as cool as possible (up to zero degrees C at least) 3. Use it as little as possible before…

Degradation is driven by many things, but a big one is heat. Elevated temperatures during both charge and discharge is very bad for battery longevity. To manage this, almost all EVs use liquid cooling, with a cold plate directly contacting as many battery cells as they can to move heat out of the battery. This coolant is then cooled by a radiator, an AC chiller, or both.

The worst temperature abuse case is DC fast charging, aka Supercharging, where high current charging creates tons of heat due to resistive losses. This is why frequent fast charging causes faster battery degradation, but ordinary charging and driving does not, because the coolant loop is sized for the DC fast charge heat transfer requirements.

Besides removing heat, adding heat into the system is also desirable. Cold weather environments approaching freezing or below is also bad for battery longevity, and more importantly, terrible for range. Resistive heaters are super power hungry, and to heat the battery coolant loop requires power from the battery. This is why, conventionally, EVs are terrible in cold weather.

> Do EV manufacturers use any other tricks not covered by this?

And now, onto the magic trick.

Heat management is so important to both the driving range and the longevity of a vehicle that EVs have moved from traditional resistive heaters to heat pumps. These magical thermodynamic devices can move heat from anywhere, including drawing heat out of cold ambient air.

When you combine that with a valve design that allows the heat pump to access the battery coolant loop, the motor drivetrain coolant loop, the cabin coolant loop, the vehicle computer(s) coolant loops, and external ambient temperature, you can have a super efficient system that shuffles heat where it's "wasted" to where it's "needed".

Tesla has an excellent video briefly covering their heat pump and their very clever Octovalve design: https://www.youtube.com/watch?v=DyGgrkeds5U

For more depth, this video covers the heat pump and the ~22 different sources of heat it can draw heat from: https://www.youtube.com/watch?v=Dujr3DRkpDU

Re: BU-808: How to Prolong Lithium-based Batteries (2023)

#50

Post by averynicepen »

avidiax wrote: post #37

I may be a bit odd, but I store lithium ion battery containing electronics in the vegetable drawer in the fridge. You lose 20% of capacity in a year if you have 100% state of charge but only 6% loss of capacity at refrigerator temperatures. So tool batteries, small electronics and whatever else that isn't used weekly gets put in. I also try to charge fully only just before use (and only if I need 100%), and store at…

Have you ever measured your battery voltages over time storing it this way? Is that 6% capacity loss theoretical or measured data? I'm intrigued. This sounds crazy, but it should technically be fundamentally sound.
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