Given the following comment, by Weber, I decided to try to narrow-down what the Kilowatt Labs "Supercapacitor Array", can, and can not be.
Except that graphene supercaps that obey the known laws of physics (as opposed to magical ones), occupy about 20 times the volume of an LTO battery with the same energy storage capacity, and presently cost about 50 times as much.
Can't work with that, so I'll try to tighten it up some.
The volume of a "coke can" varies greatly, from 135 ml, up to 500 ml. There are 19 different sizes of coke can:
https://www.ad-informatica.com/davidean ... lsizes.jpg
(gawd bless the internet)
The US standard can size is 355 ml, and Australian standard can, 375 ml.
Phrases like, "the size of a coke can", don't help us much. We need farads per millilitre (or cubic cm) to assess energy-verses-volume implications of the claimed graphene supercaps F capacity.
But let's assume the existing ultracaps equal, 355 ml of volume, for 3000 farads.
The Arvio graphene supercapacitor brochure spec says that the 3550 Wh Kilowatt Labs "Capacitor Module", has these dimensions:
(w x d x h)
600mm x 534mm x 200mm (+/-2%)
[NOTE: +/- 2% variation in width is +/-12 mm, so two cases of this product could vary in width, by as much as 24 mm! I don't think I've ever seen an error margin on a case's dimension specs before, obviously not CAD/CAM manufacture.]
Looking at the image of the "Super Capacitor" array, on the Kilowatt Labs site ( http://kilowattlabs.com/energy-storage-technology.html
), it is reasonable to presume the 160 rectangular prism devices displayed there must be oriented width wise (600 mm wide) across the case. Given that layout, the individual device's width dimension, can be no wider than 25 mm, in order to fit that whole supercap array layout into a 600 mm wide case.
From visual examinations of the depicted supercap array's architecture, it appears the individual devices are at most 4 times longer than they are wide.
So it's very likely the 160 retangular prism supercap device's dimensions are (or else very close to) 25 mm × 25 mm × 100 mm.
Volume of a cylinder with diameter 25 mm, length 100 mm = 49.1 ml.
But volume of a rectangular prism, with width 25 mm, height 25 mm, length 100 mm = 62.5 ml.
160 devices × 62.5 ml = 10,000 ml*
* Total volume of all 160 depicted supercap array devices as scaled to just fit into a case that's 600 mm wide.
So Kilowatt Labs have, at best, no more than 10,000 ml of volume for graphene (with that particular architecture) to acheive its claims, per a single 2.7V and 3550 Wh "Capacitor Module".
10,000 ml ÷ 355 ml [coke cans] = 28.2 cans
28.2 coke cans × 3000F = 84,507F (Supercap)
So we have a fairly solid basis for volume comparisons with a 355 ml USA 'coke can' @3000F for an ultracap (if that's useful).
Kilowatt Labs is claming a graphene energy density just less than 1/3 that best density recently published. They claim other companies are currently bringing similar graphene-based products to market (see quote at bottom).
MicrotronTec claims to manufacture the graphene supercaps in China. MicrotronTec says:
Unlike conventional ultracaps using Activated Carbon, Microtron’s storage cells use graphene. The higher surface area of graphene allows Microtron to deploy ultracap cells with capacitance values of up to 140,000 farads vs the 3,000 farads in most ultracapacitors on the market today.
Assuming the 140,000F refers to their Capacitor Module" prototype's F value:
140,000F [supercap array] ÷ 160 devices = 875F per supercap device.
If a 355 ml ultracapacitor is 3000F, then the deduced calculated 62.5 ml devices in the Kilowatts supercap array, would be:
355 ml ÷ 62.5 ml = 5.68 devices per coke can volume.
3000F ÷ 5.68 = 528.2F per device (if an ultracap)
160 devices ÷ 528.2 = 84.507F (ultracap)
That is, if it were a currently available ultracap tech, rather than graphene.
84.507F ÷ 140,000F = 0.603
So MicrotronTec are claiming their graphene supercapacitor devices have 39.9% more farads per ml, than the best current ultracaps, and that they can make and package the graphene caps extremely cheaply, into these long lived devices.
Frankly, it's possible that MicrotronTec's prototype 'Capacitor Module' can package 140,000 farads into a case of 600mm x 534mm x 200mm.
Having said all the above, we don't know that these 25 mm × 100 m supercaps actually exist, and if they do, what farads they actually store per device. But 140,000F is the only number they have claimed.
Kilowatt Labs's marketing chiefs seem to think the buyer should not know such things--just trust us.
Nah, sorry, extraordinary claims require extraordinary evidence---or get rejected.
We need images and specs on the actual devices, and full colour photos of the interior of a 3.55 kWh case, and an explanation of what each part is, and what these do, in full.
Both Kilowatt Labs and Paul (Supercaps) from Arvio claim a "very low percentage" of Li battery array is used, in the "Capacitor Module" (which is in line with 'TCrypytos' conclusion that a large expensive battery array makes little sense electronically, or economically). Plus the Arvio Supercapacitor Brochure specs says:
"Self-discharge | 5% after 25 days"
But that implies a substantial Li battery array is drained at that point, and at best there's just 95% charge left in the supercaps, but this will be a lot less storage remaining than the insinuated 95% of total 3550 Wh.
Yeah, right, would it really be more like ~50% of the total rated storage after that 25 days on standby?
A customer should know that sort of thing.
Why so much ambiguity? Why do we even need to figure this out? Where's the transparancy? If Kilowatt Labs wants to sell these in Australia, they need to accept that it's time to lift the dress and show us what they've got.
Graphene supercapacitors serve as energy storage alternative to traditional electrolytic batteries. Among advantages are fast charging, long life span and environmentally friendly production. Graphene supercapacitors produced by Skeleton Technologies have been commercially available since around 2015 and were first used in some specialized applications instead of traditional batteries. By 2017, commercial graphene supercapacitor units were available for industrial power applications, with maximal power output of 1500 kW. In 2016, Adgero announced a regenerative braking system (KERS) for large trucks that employed a graphene-based supercapacitor.
Given the rate of development, it's not out of the question that this graphene "Capacitor Module" is for real. But there is no evidence yet that this device is one of them. Equally, there's no clear evidence that it isn't, yet.