capacitor lipo hybrid. did i predict the future again?

[jimmyhackers]

a while ago in this post i mentioned using capcitors with lead acid batteries to reduce the peukert effect.

im sure i did a whole seperate topic/thread on it but i can find it anymore. (illuminati deleted it )

https://endless-sphere.com/forums/viewtopic.php?f=30&t=69344

recently ive seen more interest in using capacitors in conjunction with batteries and wonder if this is a relativly new idea. or weather it has been around for longer than 4 years (when i started doing it).

have i given another golden gem of an idea away? (other one was getting electricty/power froma cars exhaust)

 

[flat tire]

Lithium batteries don't suffer from peukert effect and the idea of putting a power turbine after a combustion motor is over 100 years old.

 

[jimmyhackers]

i kind of think they do suffer from a form of the peukert effect, although much less pronounced.

a lipo under heavy load will heat up....this wasted heat must be energy lost/wasted.
the heavier the load the more heat generated..i think?

i could be wrong as im not sure how detremental this is to a lipobattery, and if it is actually a thing....
i.e. say a 2ah battery at a 2amp load would last an hour and produce 10btus of wasted heat over this time. but would the same battery at a 4amp load last 30minutes and still produce 10btus of wasted heat? or would it last a shorter time than 30mins or produce more than 10btus?

i feel this isn't talked about as a form of the peukert effect, it probably is somewhere and has a proper name.

either way.....industry is starting to use capacitors in conjunction with batteries (even lipos). for quick storage and release in braking and motor boosting. i know these system are more complicated than my "add capacitor to battery" method but the idea of sharing the load between the two to spare the battery from high current spikes is the same.

i suppose when i think about it....industries sort of been doing this for ages....capacitors are there to smooth out current spikes in almost everything.

p.s. my other idea was to bolt an alternator to the exhaust half of a turbo. i posted on a car forum over 10years ago as i couldnt find anyone else who had made one... everyone said the idea was stupid......about 3-4 years later, a company starts producing them for trucks...it more likely that they didnt copy me...but i do find it funny how sometimes i have the same good but totally random idea as someone else.

 

[Grantmac]

+15 years ago I had the idea of placing the hot side of a Stirling engine into the exhaust system of a car. Haven't seen it done yet but still think it has potential.

Likewise a turbo with an alternator/motor in the center section. Add electricity to spool, charge when in steady state or deceleration.

Alas I think EVs will take over first.

 

[jimmyhackers]

evs have already taken over my life

my 306 has been sitting gathering dust for the past 2 years on my drive.

i use my ebikes for everything now.

 

[liveforphysics]

Every lithium battery you've ever used is already intrensically a super capacitor in parallel with an electrochemical cell.

This is why EVs don't have any use for adding external super caps to the battery.

 

[nicobie]

Every lithium battery you've ever used is already intrensically a super capacitor in parallel with an electrochemical cell.

This is why EVs don't have any use for adding external super caps to the battery.

I didn't know that.

Thanks!

Nick

 

[jimmyhackers]

that is very intersting. thanks for the info, love your videos btw.

although that is the case....lipo batteries still fail. meaning sometimes they are degraded/broken due to overdischarge/charge, but also they take abuse through going over the C rating of the cell (too much current draw).

as this happens in certain cases you could argue that the inherant "supercacitance" of a lipo cells isnt enough in certain situations.

i dont think adding supercapcitors to a lipo woud hurt it.
the only forseeable problem would be leaving the battery/capcitors sitting for a while as the capcitors would slowly burn off power.

i suppose if you got the right rated cells for your application you wouldnt need to bother with any of this.

 

[billvon]

Every lithium battery you've ever used is already intrensically a super capacitor in parallel with an electrochemical cell.

Well, it's a capacitor, at least.

And I would add that pretty much every battery - every battery that has parallel plates with a small amount of electrolyte between them, which is almost all of them - is also a capacitor. Some more so and some less so depending on plate area, dielectric constant of the electrolyte (and separator if used) and the distance from plate to plate.

 

[liveforphysics]

Every lithium battery you've ever used is already intrensically a super capacitor in parallel with an electrochemical cell.

Well, it's a capacitor, at least.

And I would add that pretty much every battery - every battery that has parallel plates with a small amount of electrolyte between them, which is almost all of them - is also a capacitor. Some more so and some less so depending on plate area, dielectric constant of the electrolyte (and separator if used) and the distance from plate to plate.

Supercap = Double layer capacitor. They are different than conventional caps, and the way they store charge is intrinsic to LIB's as well, just doesn't represent a significant portion of the energy storage, but does represent how it behaves when receiving pulses of input or output current.

 

[SamRich]

I work in medical imaging and Battery + Cap solution have been use for decades in the portable x-ray business that typically use SLA - although systems are slowly migrating to Li-ion.
The Cap +battery is a good solution when you need very short, very high current burst (think 200A for 1s).
I suppose it would be cool for short acceleration bursts on an ebike, but they are somewhat complicated systems to put together since you need to step up the voltage of the Caps above your battery voltage to get useful energy since caps will discharge from Max V to 0V. Your load will also need to handle that wide range of voltage. For an x-ray generator that is fine, but trickier for simple motor controller to handle. It's do-able but the added cost/weight/complexity would not be worth IMO - outside drag racing perhaps.

 

[jimmyhackers]

INDEED. this hybridization of a battery/cap does have its applications it would seem. but those applications are limited

its all wether the constant slow drain of a capacitor outweighs the power lost due to high dischagre current spikeswithout caps.

so for a long cruising ebike that stays on flat roads and top speed for long amounts of time. its probably useless

but say for a trails bike/motocross which envolves constantly messing with the throttle it could show some benefit.

i think just adding them simply in parrallel to any battery must be effective.
although i do know with other systems now, supercapcitors are being used to take in regen braking and then re disperse this energy back into the motor under acceleration to negate this wear on the battery.

iv been toying with this idea, as regen braking seems to provide a useless amount of energy for recharging the battery, but its should be more than enough to power a brake light.

doesnt anyone make a retrofit braking system that adds regen/power generation from the motor?. if not i figure making one would be rather simple.