Enersys "Zero Volt" Lithium Ion

JoeRodge

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Has anyone heard of this technology? Enersys is a pretty well known company. Hard to believe you can discharge a battery to 0V and have it come back, multiple times, without any more degradation than discharging to 3V.

https://www.enersys.com/Lithium_Ion_-_Zero_Volt.aspx?langType=1033


EnerSys recently acquired Quallion, LLC, whose patented Zero-Volt™ technology enables a lithium ion battery to be completely discharged to an inert state, stored in this condition for an extended period, and then recharged without any permanent damage to the battery or reduction in capacity or performance.
 

magellan

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Very interesting (and promising if true). I'll do that.

Being able to discharge all the way to zero gives you three times the voltage range, or thereabouts. I would wonder what the usable increase in capacity is. I can see several hurdles to overcome, not the least of which would be the dreaded dendritic crystal formation problem.
 

DIWdiver

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Wide voltage range doesn't mean crap. The best battery would have a limited voltage range, after which it would rapidly or suddenly drop to zero. It is very difficult to design a circuit that can efficiently convert power from a widely variable voltage source. The narrower the range, the better.

Voltage range also means nothing about capacity. When talking about a specific chemistry, using a wider voltage range definitely gives you higher capacity. But when talking about two different chemistries, the one with the wider voltage range does NOT necessarily have the larger capacity.

That's not to say that this isn't an exciting development. There are definitely advantages to a cell that's tolerant of over discharge, and especially to one that's tolerant to storage in a deeply or over-discharged condition. But until we see capacity, energy density, cycle ratings, etc., I'm not ready to jump off the bus I'm riding today.
 

Gauss163

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Being able to discharge all the way to zero gives you three times the voltage range, or thereabouts. I would wonder what the usable increase in capacity is [...]

The motivation has little to do with capacity gains (which will be minimal). Rather (near) zero-volt storage greatly increases safety (e.g. it increases thermal runaway threshold temperature and greatly decreases amount ofrunaway gas production, and eliminates all toxic gases, etc), so e.g. they can be shipped much more safely.
 

magellan

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Hi DIW,

Ahh, it's a safety thing. I just figured someone had finally invented a way to get more power or capacity, or some significant additional performance, from the extra volts, thereby overcoming the usual narrow operating parameters of batteries (as you pointed out). Now that would have been news.

But I suppose batteries, being these hybrid electro-chemical beasties and not just purely electrical devices, may always have these limitations.

Of course, in the case of lithium ion batteries, safety is nothing to sneeze at, as anyone who hangs out for very long on CPF knows.
 
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magellan

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The motivation has little to do with capacity gains (which will be minimal). Rather (near) zero-volt storage greatly increases safety (e.g. it increases thermal runaway threshold temperature and greatly decreases amount ofrunaway gas production, and eliminates all toxic gases, etc), so e.g. they can be shipped much more safely.

Well, safety is certainly important too, and as anyone who spends much time here learns, there's a lot you can do to observe proper battery safety and charging discipline. But you're more likely to get run over crossing the street in broad daylight than to have a lithium ion battery incident—even if you're in the habit of abusing your batteries—which I don't—although of course certain chemistries are more tolerant than others.

So (not having read any articles yet, but I will), I assume we're talking about current lithium ions of some sort? NiMH batteries, by comparison, are already able to be completely discharged, IIRC.

A brief search turned up this approach for a zero volt capable lithium ion battery:

[FONT=museo_sans300]"Thus, modifying the amount of reversible lithium in a cell with anode pre-lithiation is a promising concept to achieve lithium ion cells with high tolerance to near zero volt storage without modification to typical cell construction parameters or use of unconventional materials."

[/FONT]https://pubs.rsc.org/en/content/articlelanding/2016/ee/c6ee00836d#!divAbstract

Is there some reason pre-lithiation wasn't done before?

Also, I'm not sure I'm understanding how pre-lithiation works. Are they saying that using this approach, discharging to zero doesn't generate much heat or hydrogen gas, etc? If so, it sounds like not much real work is being done during that phase, otherwise there would be more heat generated and released. Hence, there's very little increase in energy or capacity (as DIY explained), but the battery still has the capability of going to near zero, to take advantage of those beneficial effects. But I'm not sure I'm understanding this correctly.
 
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