The Arrenhius Equation and the lifespan of supercapacitors?
January 13, 2024 6:21 AM Subscribe
If a 1.5 farad, 5.5 volt gold film supercapacitor has a rated service life of 20 years at 30°C and 80 years at 10°C, does that doubling continue down toits minimum specified operating temperature of -20°C?
The Arrenhius Equation appears to predict that service life will double for every 10ºC reduction in temperature. Does this indeed mean that a supercapacitor would theoretically have a service life of 640 years at -20°C?
Most of what I have found seems to focus towards the 80°C maximum end of the range of specified operating temperature and its impact on supercapacitors in hot environments.
How closely do these theoretical service life ratings apply in practical circumstances?
The Arrenhius Equation appears to predict that service life will double for every 10ºC reduction in temperature. Does this indeed mean that a supercapacitor would theoretically have a service life of 640 years at -20°C?
Most of what I have found seems to focus towards the 80°C maximum end of the range of specified operating temperature and its impact on supercapacitors in hot environments.
How closely do these theoretical service life ratings apply in practical circumstances?
... microcracking caused by thermal stress ...
In particular the difference in CTE (coefficient of thermal expansion) between different adjacent materials in the supercap. Materials expand and contract at different rates over temperature. The further you depart from the original fabrication / solidification temperature of the device, the more stress you put on each material junction, and the sooner dislocations will arise.
As the Wikipedia article says: "Currently, it is best seen as an empirical relationship." I would take it as a rough rule of thumb over a narrower range of temperatures.
Most of what I have found seems to focus towards the 80°C maximum end of the range of specified operating temperature and its impact on supercapacitors in hot environments.
Supercap clusters (and many other components rated at 70 - 80C) are used in instruments for downhole oil and gas drilling at temperatures up to 175C and even 200C. They don't last long, but they (usually) last long enough to get the job done (low hundreds of hours, I believe). At the other extreme, the instruments might be stored at -40C in Siberia before and after they are used.
I have access to a few decades of Society of Petroleum Engineers (SPE) conference papers, where I'm sure there are a few articles on supercap applications in the oilfield. I can do a search and send you a couple if you like. MeMail me if you're interested.
posted by ZenMasterThis at 11:13 AM on January 14, 2024 [2 favorites]
In particular the difference in CTE (coefficient of thermal expansion) between different adjacent materials in the supercap. Materials expand and contract at different rates over temperature. The further you depart from the original fabrication / solidification temperature of the device, the more stress you put on each material junction, and the sooner dislocations will arise.
As the Wikipedia article says: "Currently, it is best seen as an empirical relationship." I would take it as a rough rule of thumb over a narrower range of temperatures.
Most of what I have found seems to focus towards the 80°C maximum end of the range of specified operating temperature and its impact on supercapacitors in hot environments.
Supercap clusters (and many other components rated at 70 - 80C) are used in instruments for downhole oil and gas drilling at temperatures up to 175C and even 200C. They don't last long, but they (usually) last long enough to get the job done (low hundreds of hours, I believe). At the other extreme, the instruments might be stored at -40C in Siberia before and after they are used.
I have access to a few decades of Society of Petroleum Engineers (SPE) conference papers, where I'm sure there are a few articles on supercap applications in the oilfield. I can do a search and send you a couple if you like. MeMail me if you're interested.
posted by ZenMasterThis at 11:13 AM on January 14, 2024 [2 favorites]
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posted by ReferenceDesk at 11:33 AM on January 13, 2024 [5 favorites]