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About the article I was given from:
Lithium-ion Safety Concerns Battery University
Could this portion possibly be what they're misconstruing?
"In addition to the mechanical safeguards, the electronic protection circuit external to the cells opens a solid-state switch if the charge voltage of any cell reaches 4.30V. A fuse cuts the current flow if the skin temperature of the cell approaches 90°C (194°F). To prevent the battery from over-discharging, the control circuit cuts off the current path at about 2.50V/cell."
Are they talking about the same volts as a PV lithium battery? (or are they full of it?) My vv goes up to 5v, thank you very much.... and obviously is not shutting off at 2.5v. What?
Actually, the voltage of the battery and what the PV can put out aren't the same thing, as fabricator4 points out. Voltage regulators change the battery output to what's needed or desired (within the laws of physics of course
). Batteries are chemical beasties and the voltage any kind of cell can produce depends on the chemistry in ways which remind me I only took one year of chemistry in college and no more.
If you care, you can check the chart about halfway down here:
Lithium-based Batteries Information. You don't have to "study" it or anything, just notice the voltages listed have to do with the chemistry (LiMn2O4 puts out 3.8 volts and charges at 4.2 etc.). That's just true in general of the battery. X chemistry produces Y voltage per cell. I've never bothered to look but I'm sure there are chemical type reasons the common battery we stick in our TV remotes is always multiples of 1.5 volts (1.5, 3.0, 6.0, 9.0... all multiples of 1.5 and, yeah, there are 4.5 volt batteries out there, they're just not common... there may be 7.5 and 10.5 for that matter).
And, of course, because of physics and chemistry and all, integrated circuits that run all our fancy widgets often prefer 5 volts. So when I putz around with "widgets", I more likely than not have 9 volt batteries lying around but need 5 volts. So I have a batch of cheap voltage regulator chips that change the 9 to 5. This kind of thing is so common in the electronics world, it's literally down to dirt cheap chips that will change X voltage to Y and you don't "build" anything. You buy the regulators you want, slap 'em in the circuit.
On top of that, there are the "variable" regulators. Of which, you have one. Or a few. I have three. They're called "Joyetech Twist batteries".
I spin a knob and the regulator says, "ah, he wants 4 volts". And the battery being a 3.6 or 3.8 (lithium ions seem to cluster around 3.7 and are often just marked 3.7v) isn't a problem. An output higher than the battery is producing will run through the charge faster but I like my vape warm and I don't care I'm having to recharge a little more often.
But the output of the PV does not have to be exactly the input of the battery. There are limits (laws of physics and all) but there is wiggle room.
The discussion you quote above, though, applies
in general to lithium ions. Including to the cell phone your supervisor may well have up against her head on a regular basis. I would suggest donning a mask when she talks on her phone and explaining, when asked, "You said lithium ion batteries produce carcinogens" but, there again, we see why Mark does not play well with others.
(Most of my professional life, I've been an independent contractor and "work at home" type. I just do not do well in an office environment.
)
Anyway. Now standardized circuitry keeps the batteries in check. Which is what they're talking about there. Notice this bit:
A fuse cuts the current flow if the skin temperature of the cell approaches 90°C (194°F). To prevent the battery from over-discharging, the control circuit cuts off the current path at about 2.50V/cell."
In the early days (almost twenty years ago), there were some dramatic failures of lithium ions. Laptops catching fire for instance. Big, dramatic recalls (though the failure rate was about one in 200,000 which is pretty low but, still, people were rattled over the idea of something meant to be in their laps bursting into flames... and yeah, that's a disturbing thought
). Any battery that is discharging too fast will heat up. "Dead short" a battery from your TV remote, it'll heat. Might even burn you. I've almost got burnt from plain old 9 volt batteries when I've slipped and shorted one.
So there are fuses built into these batteries now that cut the power if the battery's temp gets too high. In fact, so much work has gone into making them safe, they're safer than the one in your car. Lead acids are actually very dangerous batteries. I'll change my own car battery (and mom's) but I have heavy gloves and eye protection on. I'll trust a lithium ion over a lead acid any day.
(Car batteries actually produce amperage high enough to stop your heart. My PV can't do that.)
But, yes, your battery has a high voltage limit and low voltage limit. And your PV has circuitry to enforce that. We've been doing this a while and know these batteries pretty well. They're very, very safe.
In fact, your health and life are at
far greater risk driving to work. 20 years of lithium ions, I can't think of a single death caused by one. Cars? Those things have killed around a million people in the same period...
