Do Electrolytic Capacitors FREEZE?

They do presumably have some temperature at which they'll freeze, given that everything (helium possibly excepted) does.

The data sheet will give an operating temperature range. For example

specifies a lower limit of -55 Celsius, which should be OK in most parts of the world (memo to self - don't move to Siberia).

That said, I would expect the performance to decrease with temperature, which could cause issues if the designer has been insufficiently conservative. Even then, I'd have thought the effect would only be noticeable when the radio was being played very loud.

Sylvia.

It's water-based, but the water does contain electrolytes, so the freezing point will be a lot lower than pure water. Brine rejects salt as it freezes , so that the ice that forms on the top of the Arctic Sea contains a lot le ss salt than sea-water. Whether this would happen in an electrolytic capaci tor is an open question for me - the electrolyte isn't sodium chloride, and I don't know nearly enough to even speculate.

Capacitors are rarely a problem in automotive applications. Automotive applications are generally specified from -40C to +85C, ambient. There are many capacitors to choose from that will satisfy that range. Inductors tend to be more problematic (and easier to forget to derate

- and tend to make things explode). Note that the electronics heats fairly rapidly after the car is started so the lower end of the temperature range is rarely a problem, particularly for infotainment components.

It's water based, IIRC the second major constituent is borax.

because the water is not pure is freezes at a reduced temperature.

oil freezes too - that's what wax is.

Jasen Betts wrote in news:q0rtp2$j7h$ snipped-for-privacy@gonzo.alcatraz:

This is (well... was) one of the primary limiting factors for cold circuit operation (sealed zero humidity box) Capacitors (electrolytic and a few other types) change characteristics of their function at reduced temperatures.

This is why contracts for products which can withstand extremes of cold or hot temperatures are so much more expensive.

Thanks for sending me on a chase. Turns out, most eleytrolytes seem to be t rioxoides or pentoxides. (just takes the right keywords)

Mostly, oxides are not really in a state of matter like an element. They ca n be really funny, don't want to melt, don't want to do anything. One elect rolyte is actually an ore !

One poster said something about them being water or oil based, which matter s. I can tell you they are mostly oil based. Oils do not freeze easily, oxi des do not freeze easily. Mixed, in SOME cases might be different but usual ly their melting, freezing, evaporating points are not much different than their component parts. I could not get absolutely specific data on this on short notice but if the laws of physics apply I should not be far off.

As such, I have some conclusions and they are partly built on my experience in the service industry.

As one poster put it, is it water or oil ? Well I say oil. Many years ago o ne lytic maker stole a formula that was not complete and used it, made grea t lytics. They were simply wonderful, initially. However over time the liqu id part of the electrolyte would leak out. It got all over the board. At fi rst it wasn't all that bad but it did corrode the copper traces off the boa rd after some time and caused all kinds of problems, and soaked into the PC material and REALLY got hairy to remove. (and was CONDUCTIVE) Since these units went up to like $7,000 I had to fix them. The cleaning process of the boards was formidable. But then I got top buck and was the only one to get them up and running. And I had to develop the process.

I can only conclude that the true electrolyte was dissolved or in suspensio n in some sort of oil. It was NOT soluble in water, it took a few chemicals to do it,. Some were so bad I had to remove some of the components from th e board before the process.

Bottom line is that heat seems to make the liquid part of the electrolyte c ome out when it leaks, but some must stay in because almost amazingly these electrolytics checked good ! And I mean leakage as well.

Oxides are generally insulators. What it seems is they are a better insulat or than air or oil alone. To add a solid to a liquid and give it better die lectric properties is a mater for a chemist. If I was a chemist I would be in South America making drugs. (well not really)

Anyway, looking at the way lytics fail, it is the lower voltage ones that d evelop leakage, like sometimes when they put one right across the B-E of a BJT, it gets leaky usually, not developing ESR. What's more we have old lyt ics sitting on the shelf too long that just go bad without a volt ever bein g out on them. Then we have them just short out for no reason.

Why ? I have done much failure mode analysis, but not being a chemist I can only report the results of the chemistry. If someone could explain all thi s about the chemistry that would be great, however that is not likely becau se nobody will have vast enough experience. To analyse all electronics repa irs for the failure modes ? I think not.

Now Jeff Lieberman here did do some temperature studies on lytics with some accurate instruments and found of course that lyitcs lose capacity and/or gain ESR at low temperatures. So you can get higher performance at higher t emperatures but it will decrease their life. (oils DO evaporate)

Now extreme cold, if you think about it from an engineering standpoint and think "Well maybe this thing will have to work at XXX degrees then I will u se a higher value that will certainly do it".

Or get fired.

In a modern SMPS, you can replace a bank of lytics that add up to 50,000uF with a 100uF and it will work. But for how long ? With whatever ESR it has, that makes it dissipate heat. That heat will cause the liquid portion of t he lytic to ooze out. It may just vent some gas or it may make a piece of l andfill out of your $5,000 Mitsubishi projection TV.

For consumer electronics, and I know most of you here would never do it, I believe that Mitsubishi KNEW about the flawed formula and bought it anyway to limit the life cycle of their products. They live by selling product, if the old product lasts forever then they sell nothing, and I got what I con sider absolute proof of it. Want it ? I have no hosting right now, though I think I can get it for one image for this, to prove what they did. And bus iness is business. In fact the whole story about the stolen formula could b e bullshit, just propagated to keep expert techs from making their conclusi ons public and wrecking their market by accusing them.

Business is business.

I'll mail you that grain of salt.

Along the lines of not quite knowing -- I understand that organic additives are used, which may be at the right concentration to give a eutectic with water and the other things. Or something near there. In which case, crystallization, or total freezing at least, won't happen until much lower temperatures.

It could also be that the combination happens to solidify into a glass, rather than crystallize.

In any case, the capacitor is completely useless at temperatures near there: ESR rises hyperbolically at low temperatures. This is due to ionic mobility, probably in turn due to viscosity, but also ionic size or somesuch. Obviously, when it completely solidifies (however it does), ESR becomes infinite, and you're left with a much lower value capacitor (since, it is still a bunch of metal wound up together, and the dielectric constant of the frozen electrolyte will be modest; but that'll be on the order of

Tim

Of course, if there's any current flowing through the capacitor, a high ESR means more ohmic heating.

Ions still migrate through solids - there are solid electrolytes - so ESR won't become infinite, and might not even become all that large.

With pure ice - and you won't get that inside an electrolytic capacitor - ionic conduction is by quantum mechanical tunneling of hydrogen ions.

What makes you think that?

This sounds like your "infinite" ESR ...

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Close, though that seems to be tantalum. So those would be wet slug, hermetically sealed tantalum? Big big $$, not the same sort of thing we're talking about unfortunately. Neat to know what's inside them.

I wonder if the same system works for aluminum. They don't claim aluminum on the patent, so it's probably somewhere between useless and corrosive? Who knows...

Tim

Yes, they are water based and freeze. ESR skyrockets below 0C. Some data sheets have graphs.

Polymer lytics and dry tantalums are much better.

In a power supply, the increased ESR will heat them up fast!

Yes, some. Glass is a good insulator at room temperature, but a modest conductor at nearly red heat (coincidentally at about annealing temperature). A matter of degree.

Sounds slow.

If there are glycols as Lasse's example has, there could be a lot more opportunity for that. Those sorts of things tend to congeal rather than crystallize, AFAIK.

Physics?

Well yeah, I just described a parallel capacitor equivalent, where the electrolytic part (1000s uF) has a temp-dependent ESR, and in parallel with that is a small non-electrolytic part (~0.1uF?) probably itself with low ESR. And then ESL in series with all of that. And also an infinite series of loss factors associated with everything, if you must be precise...

Tim

Some numbers on the first page.

ESR has a general negative TC but gets serious below 0C.

I like this question.

We have -50C freezer at work that we have test to see if products start up down around -40C/F and they did after a couple of fixes... BUT they (PV charge controller) weren't ran at any power.

What I would like to try is to place an electrolytic or two or three in there and bring out wires to be able to test this at say, -50C.

And in-between temperatures if the caps are bad at -50

On Jan 5, 2019, snipped-for-privacy@myshop.com wrote (in article):

Yes, they can freeze. The aluminum electrolytics I was looking any a few years ago froze at -20 C or so, the main symptom being that the capacitance went down to one third of warm value, and the ESR rose. The big worry was that the regulators in the power supply tree could become unstable and oscillate quite heartily.

Joe Gwinn

Why do inductors have an operating temperature range at all?

"Tom Del Rosso" wrote in message news:q0ttt0$6kh$ snipped-for-privacy@dont-email.me...

Ferrites freeze out a bit (not enough to ruin the spec in most cases, I think?), and obviously the upper limit is set by materials. I don't think there's anything beyond that -- just that they're not tested below there (and probably they can charge more if you want to buy ones that are?).

Oh, and probably resins glassifying, and shrinkage.

Tim

Joseph Gwinn wrote in news: snipped-for-privacy@news.giganews.com:

Essentially what happens is that your circuit is no longer your circuit because caps of other than designed values are currently what is in place at whatever temp below freezing you are at.

So oscillations and various other non-optimal operational modes and failure modes can occur.

"Tom Del Rosso" wrote in news:q0ttt0$6kh$ snipped-for-privacy@dont-email.me:

In the cold end they vary very little. In high temps a few things can happen. One is that the transformer varnish it was likely vacuum encapsulated in will liquify at some point.

For HV applications, this can pose an arcing potential issue. Not likely but an operating range has to be stated, and it will likely be well below the melt point of any polymers or varnishes used in its make-up.

This refers to miniature form factors of course. Huge oil bath power transformers are made with paper products and few polymers. There are plenty of isolation transformers, etc. and other designs where high temps pose no problem far higher than those a circuit board sized miniature can withstand.