4 ms·

More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB (if we exclude non-negotiable part

by atoav 3y ago

More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB (if we exclude non-negotiable parts like connectors, buttons, displays, etc.) But I'd like to add that it might take a long while for the results of this work getting into market. For circuit designers it is crucial to know under which conditions and after which time capacitors fail (and in which way they fail). This is all knowledge that has to be generated before such a thing goes to market. And usually you don't wanna be the early adopter on things like these

logtempo 3y ago
is it a big deal ? Any components need to pass some conformity tests, and testing capacitors is an established process. There are bike with supercapacitors out there, so it's definitly not that far from the market.
tomxor 3y ago
> More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB I don't think it's that simple, energy density and power density seem to be roughly inversely related across technologies. i.e the more energy you can pack per unit mass the slower it is to get it in and out. A substantially lower power density could actually make the equivalent component larger or heavier for many purposes. Super capacitors already exist that bridge the gap between electrolytic capacitors and chemical batteries. If you compare the specific energy with the specific power of each the ratio drastically changes from left to right in this table with old electrolytics beating everything when it comes to power: https://en.wikipedia.org/wiki/Supercapacitor#Comparison_with_other_storage_technologies https://en.wikipedia.org/wiki/Supercapacitor#Comparison_with... On the other hand this comparison is per unit mass, and these technologies differ vastly in volume density, so a comparison per unit volume would reduce the differences in power density. I'm pretty sure the order for power density will be the same though.
- ComputerGuru 3y ago
  > energy density and power density seem to be roughly inversely related across technologies. i.e the more energy you can pack per unit mass the slower it is to get it in and out. This sounds really elegant and simple to the point where people might take it as an axiomatic fact but the very existence of both nuclear fission and fusion stops it from being a general rule. They’re both discharging power from individual atoms and it would actually be great if we had a way to slow down the rate of discharge.
  - lazide 3y ago
    It also has plenty of plain old basic chemistry examples showing it false - lithium ion vs lead acid, gasoline vs fuel oil, etc.
  - tomxor 3y ago
    Yes, it's only a high level observation, but one that seems to hold true for electrical storage so far, i.e where there is a closed system with an electrical input and output. For fusion there are also various direct energy conversion methods for electrical output, but not the reverse, i.e i don't think there is method for nucleosynthesis directly from charged particles. In a more general sense, sure, power vs energy relation doesn't hold, but when limiting the system to the requirements to be a self contained electrical storage component, this relationship seems to emerge.
crote 3y ago
> More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB Not really. Most modern electronics don't need significant capacitance in F. Your selection of capacitors will be dominated by a very large number of physically small, low-value bypass capacitors, one each placed as close as possible to every single power pin. The main thing you care about is their inductance - which is why you want them small and close to the pin. I'm already using the smallest parts the factory lets me without charging a premium fee, so nothing to gain here. Beyond that there might be a handful of bulk capacitors distributed among the power rails, but those are rare and already rice-sized. Making those smaller wouldn't hurt, but it's not the first property you'd be selecting it on, and the potential gains are pretty much wasted on anything which isn't an iPhone. There are still some rather bulky capacitors in things like chargers and power supplies, but those aren't exactly space-limited.

by atoav 3y ago

logtempo 3y ago

is it a big deal ? Any components need to pass some conformity tests, and testing capacitors is an established process. There are bike with supercapacitors out there, so it's definitly not that far from the market.

tomxor 3y ago

> More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB I don't think it's that simple, energy density and power density seem to be roughly inversely related across technologies. i.e the more energy you can pack per unit mass the slower it is to get it in and out. A substantially lower power density could actually make the equivalent component larger or heavier for many purposes. Super capacitors already exist that bridge the gap between electrolytic capacitors and chemical batteries. If you compare the specific energy with the specific power of each the ratio drastically changes from left to right in this table with old electrolytics beating everything when it comes to power: https://en.wikipedia.org/wiki/Supercapacitor#Comparison_with_other_storage_technologies https://en.wikipedia.org/wiki/Supercapacitor#Comparison_with... On the other hand this comparison is per unit mass, and these technologies differ vastly in volume density, so a comparison per unit volume would reduce the differences in power density. I'm pretty sure the order for power density will be the same though.

ComputerGuru 3y ago
> energy density and power density seem to be roughly inversely related across technologies. i.e the more energy you can pack per unit mass the slower it is to get it in and out. This sounds really elegant and simple to the point where people might take it as an axiomatic fact but the very existence of both nuclear fission and fusion stops it from being a general rule. They’re both discharging power from individual atoms and it would actually be great if we had a way to slow down the rate of discharge.
- lazide 3y ago
  It also has plenty of plain old basic chemistry examples showing it false - lithium ion vs lead acid, gasoline vs fuel oil, etc.
- tomxor 3y ago
  Yes, it's only a high level observation, but one that seems to hold true for electrical storage so far, i.e where there is a closed system with an electrical input and output. For fusion there are also various direct energy conversion methods for electrical output, but not the reverse, i.e i don't think there is method for nucleosynthesis directly from charged particles. In a more general sense, sure, power vs energy relation doesn't hold, but when limiting the system to the requirements to be a self contained electrical storage component, this relationship seems to emerge.

crote 3y ago

> More energy density in capacitors is a big thing, as capacitors are easily the biggest parts you will have to use on your PCB Not really. Most modern electronics don't need significant capacitance in F. Your selection of capacitors will be dominated by a very large number of physically small, low-value bypass capacitors, one each placed as close as possible to every single power pin. The main thing you care about is their inductance - which is why you want them small and close to the pin. I'm already using the smallest parts the factory lets me without charging a premium fee, so nothing to gain here. Beyond that there might be a handful of bulk capacitors distributed among the power rails, but those are rare and already rice-sized. Making those smaller wouldn't hurt, but it's not the first property you'd be selecting it on, and the potential gains are pretty much wasted on anything which isn't an iPhone. There are still some rather bulky capacitors in things like chargers and power supplies, but those aren't exactly space-limited.