Do Electrolytic Capacitors FREEZE?

I have never known what the electrolyte is made from, inside of
electrolytic capacitors. Is it a water based material, or oil based? 
If its water based, it will likely freeze if left outdoors in cold
weather. For example, your car radio has caps, and if it's parked
outdoors in the winter, the caps in it will freeze. Yet, I have never
found my car radio working poorly in cold weather. This makes me believe
the electrolyte must be oil based.....

Does anyone know?

On 6/01/2019 11:48 am, tubeguy@myshop.com wrote:
> I have never known what the electrolyte is made from, inside of
> electrolytic capacitors. Is it a water based material, or oil based?
> If its water based, it will likely freeze if left outdoors in cold
> weather. For example, your car radio has caps, and if it's parked
> outdoors in the winter, the caps in it will freeze. Yet, I have never
> found my car radio working poorly in cold weather. This makes me believe
> the electrolyte must be oil based.....
> 
> Does anyone know?
> 

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

https://docs-apac.rs-online.com/webdocs/0bec/0900766b80becf93.pdf

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.

On Sunday, January 6, 2019 at 11:48:59 AM UTC+11, tub...@myshop.com wrote:
> I have never known what the electrolyte is made from, inside of
> electrolytic capacitors. Is it a water based material, or oil based? 
> If its water based, it will likely freeze if left outdoors in cold
> weather. For example, your car radio has caps, and if it's parked
> outdoors in the winter, the caps in it will freeze. Yet, I have never
> found my car radio working poorly in cold weather. This makes me believe
> the electrolyte must be oil based.....
> 
> Does anyone know?

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 less salt than sea-water. Whether this would happen in an electrolytic capacitor is an open question for me - the electrolyte isn't sodium chloride, and I don't know nearly enough to even speculate.

-- 
Bill Sloman, Sydney

On Sat, 05 Jan 2019 18:48:46 -0600, tubeguy@myshop.com wrote:

>I have never known what the electrolyte is made from, inside of
>electrolytic capacitors. Is it a water based material, or oil based? 
>If its water based, it will likely freeze if left outdoors in cold
>weather. For example, your car radio has caps, and if it's parked
>outdoors in the winter, the caps in it will freeze. Yet, I have never
>found my car radio working poorly in cold weather. This makes me believe
>the electrolyte must be oil based.....
>
>Does anyone know?

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.

On 2019-01-06, tubeguy@myshop.com <tubeguy@myshop.com> wrote:
> I have never known what the electrolyte is made from, inside of
> electrolytic capacitors. Is it a water based material, or oil based? 
> If its water based, it will likely freeze if left outdoors in cold
> weather. For example, your car radio has caps, and if it's parked
> outdoors in the winter, the caps in it will freeze. Yet, I have never
> found my car radio working poorly in cold weather. This makes me believe
> the electrolyte must be oil based.....

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.

-- 
  When I tried casting out nines I made a hash of it.

Jasen Betts <jasen@xnet.co.nz> wrote in
news:q0rtp2$j7h$1@gonzo.alcatraz: 

> On 2019-01-06, tubeguy@myshop.com <tubeguy@myshop.com> wrote:
>> I have never known what the electrolyte is made from, inside of
>> electrolytic capacitors. Is it a water based material, or oil
>> based? If its water based, it will likely freeze if left outdoors
>> in cold weather. For example, your car radio has caps, and if it's
>> parked outdoors in the winter, the caps in it will freeze. Yet, I
>> have never found my car radio working poorly in cold weather. This
>> makes me believe the electrolyte must be oil based.....
> 
> 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.
> 

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 trioxoides or pentoxides. (just takes the right keywords)

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

One poster said something about them being water or oil based, which matters. I can tell you they are mostly oil based. Oils do not freeze easily, oxides do not freeze easily. Mixed, in SOME cases might be different but usually 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 one lytic maker stole a formula that was not complete and used it, made great lytics. They were simply wonderful, initially. However over time the liquid part of the electrolyte would leak out. It got all over the board. At first it wasn't all that bad but it did corrode the copper traces off the board 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 suspension 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 the board before the process. 

Bottom line is that heat seems to make the liquid part of the electrolyte come 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 insulator than air or oil alone. To add a solid to a liquid and give it better dielectric 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 develop 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 lytics sitting on the shelf too long that just go bad without a volt ever being 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 this about the chemistry that would be great, however that is not likely because nobody will have vast enough experience. To analyse all electronics repairs 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 temperatures 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 use 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 the lytic to ooze out. It may just vent some gas or it may make a piece of landfill 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 consider 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 business is business. In fact the whole story about the stolen formula could be bullshit, just propagated to keep expert techs from making their conclusions public and wrecking their market by accusing them. 

Business is business. 

I'll mail you that grain of salt.

<bill.sloman@ieee.org> wrote in message 
news:2e221313-8d6e-42c4-a8de-e48e9a942fbf@googlegroups.com...
>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 less salt than sea-water. Whether this would happen in an electrolytic 
>capacitor is an open question for me - the electrolyte isn't sodium 
>chloride, and I don't know nearly enough to even speculate.
>

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 
0.1uF versus a nominal value of 1000s uF, useless for the same purpose).

Tim

-- 
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/ 

On Sunday, January 6, 2019 at 9:05:37 PM UTC+11, Tim Williams wrote:
> <bill.sloman@ieee.org> wrote in message 
> news:2e221313-8d6e-42c4-a8de-e48e9a942fbf@googlegroups.com...
> >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 less salt than sea-water. Whether this would happen in an electrolytic 
> >capacitor is an open question for me - the electrolyte isn't sodium 
> >chloride, and I don't know nearly enough to even speculate.
> >
> 
> 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. 

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

> Obviously, when it completely solidifies (however it does), ESR 
> becomes infinite,

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.

> 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;

What makes you think that?

> but that'll be on the order of 
> 0.1uF versus a nominal value of 1000s uF, useless for the same purpose).

This sounds like your "infinite" ESR ...

-- 
Bill Sloman, Sydney 

søndag den 6. januar 2019 kl. 11.05.37 UTC+1 skrev Tim Williams:
> <bill.sloman@ieee.org> wrote in message 
> news:2e221313-8d6e-42c4-a8de-e48e9a942fbf@googlegroups.com...
> >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 less salt than sea-water. Whether this would happen in an electrolytic 
> >capacitor is an open question for me - the electrolyte isn't sodium 
> >chloride, and I don't know nearly enough to even speculate.
> >
> 
> 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.
> 

http://www.freepatentsonline.com/6939774.html