And higher c-rates for both. I think specifically what they are doing is still a mystery.PlatinumZealot wrote: ↑17 Oct 2018, 11:48As said further up in this thread...
A battery for rapid cycling - MGUH 'tings
And a battery for slower cycling - MGUK 'tings
mystery solved...
This would also explain the much bigger size of the Ferrari unit compared to Honda, despite the 25kg limit. Supercaps would be of less capacity but lighter and bigger, so the overall ES size should be bigger, but about the same mass.Brake Horse Power wrote: ↑16 Oct 2018, 23:56What if it is a 2 piece battery because part one is saft pouch type lithium battery. Part 2 is an extremely efficiënt supercap which is able to be instantly charged and uncharged. The abity to react quickly very efficient could make sense when combined with the 20hz MGU-H generating. Energy density is lower than lithium tough, so if the supercap is flooding this energy will need to go to the lithium battery.
Skeletontech actually mentions supercaps is very suitable for KERS applications.
https://www.skeletontech.com/high-end
Capacitors aren't meant for big storage, they are meant for rapid charge and discharge, to act as a buffer for a battery. They may have batteries and capacitors combined, where the capacitor has enough charge capacity to accept whatever load from the electrical machines, and to feed that energy to the ES at a more favorable rate and vice versa.subcritical71 wrote: ↑17 Oct 2018, 16:21I took a look at the use case webinar on the skeleton tech site. I have to say the 'formula car', which appears to be Formula E ??, slide doesn't make any sense to me.
https://i.imgur.com/1Ksb0fq.jpg
Positives:
- They state Li-Ion can only harvest up to 70% of braking energy
- Ultracapacitor can harvest up to 95% of braking energy
- Lighter, more saved energy, 5x less volume(!)
Negatives:
- Its a sales webinar, there are no negatives!
Inconsistencies:
- Ultracapacitor weight 25kg, Energy (Only!) 50 Wh - Am I missing something on the capacitor rating?
Edit: Here is the page with their documentation (requires signup to view): https://www.skeletontech.com/downloads
I'm sorry for my late answer.
I understand your reasoning on the difference between the demands of the race and qualifying. However I don’t think they need to be concerned about qualifying. Providing the battery is safe and can provide energy it doesn’t matter how efficient it is during qualifying. If it operates at a low efficiency at the 180kW you propose any shortfall can be made up with energy pre-charged in the pits before the qualifying session. The reckoning of energy in and out, and SOC, is done with a single sensor at the connection point between the ES and the ERS controller. It only cares about the energy flows. It won’t mind if some of that flow comes from pre-charge or not.sosic2121 wrote: ↑17 Oct 2018, 20:13I'm sorry for my late answer.
When "Ferrari 2 batteries" became a thing, I considered Li-ion + supercapacitors. After doing some research and lots of thinking, I had a "feeling" that by optimising one part of the battery, you compromise the other part too much.
Maybe if ES had to do only race laps, then you could rate battery at 60kw(or 120kw) and have SCs to add another 120(or 60).
But during Q big portion of the lap ES outputs 180kw. If SC can keep with those demands, then use li-ion batteries in the first place!?
Basically, what ever battery you choose for some part, is 10kgs of it more efficient than 20kgs of "regular" battery?
IMO I don't think so.
that is illegal per appendix 3
The amount of stored energy in any ES may not be increased whilst the car is stationary in the pit lane or garage during the qualifying session or during a race pit stop.
It can be charged prior to both race and qualifying. Hence the term “during”.
You are right, efficiency is not important during Q.henry wrote: ↑17 Oct 2018, 23:35I understand your reasoning on the difference between the demands of the race and qualifying. However I don’t think they need to be concerned about qualifying. Providing the battery is safe and can provide energy it doesn’t matter how efficient it is during qualifying. If it operates at a low efficiency at the 180kW you propose any shortfall can be made up with energy pre-charged in the pits before the qualifying session. The reckoning of energy in and out, and SOC, is done with a single sensor at the connection point between the ES and the ERS controller. It only cares about the energy flows. It won’t mind if some of that flow comes from pre-charge or not.sosic2121 wrote: ↑17 Oct 2018, 20:13I'm sorry for my late answer.
When "Ferrari 2 batteries" became a thing, I considered Li-ion + supercapacitors. After doing some research and lots of thinking, I had a "feeling" that by optimising one part of the battery, you compromise the other part too much.
Maybe if ES had to do only race laps, then you could rate battery at 60kw(or 120kw) and have SCs to add another 120(or 60).
But during Q big portion of the lap ES outputs 180kw. If SC can keep with those demands, then use li-ion batteries in the first place!?
Basically, what ever battery you choose for some part, is 10kgs of it more efficient than 20kgs of "regular" battery?
IMO I don't think so.
As an example, suppose the car starts a qualifying lap with 16MJ ceiling charge in the ES, during the lap the ES sensor sees an input during part throttle operation of 20 seconds at an average rate of 140kW. That’s 2.8MJ that might have been stored, but if the efficiency of the ES at that rate is 90% only 2.5MJ gets stored. During e-boost operation on that lap the ES sensor would see a discharge rate of 180kW. If the efficiency is similar then to send all of the charge that’s been recorded as available(2.8MJ) the ES would need to provide 3.1MJ. The shortfall of 0.6MJ would be made up for by using energy pre-charged in the car before qualifying.
These are completely made up numbers but I think they show that efficiency during qualifying is unlikely to be a consideration for battery organisation other than for consideration of battery operating temperature and cooling.
In qualifying the ES could be charged before the first lap in Q1. But it cannot be for any subsequent lap - if a driver does 2 runs in each session, that is 5 runs that they cannot pre-charge.henry wrote: ↑17 Oct 2018, 23:49It can be charged prior to both race and qualifying. Hence the term “during”.