For high drain applications, 18650 cells are being slowly supplanted by 21700 cells, or sometimes LiPo pouches (which can offer higher currents do to their construction. But the 21700 cells, from a safety perspective, are just a more dangerous 18650—if mishandled.

One of my favorite sources for cylindrical Lithium cells is the 18650 Battery Store. They have excellent pricing, service, and selection and specialize in cylindrical Lithium cells including the newer 21700 form factor. (They also offer battery building supplies and prismatic LiFePO4 cells and complete batteries)

I recently received a promotional email from them that included a reduced price on Samsung 40T(3) 21700 cells. These are among the best you can get and offer 4000mAh capacity with a 35A continuous current rating and peak currents even higher. They are used by premium cordless tool manufacturers in their high end packs, and in other demanding applications—good stuff.

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But at that much capacity, and those kind of currents, it shouldn't take much to work out they are not to be toyed with. They have excellent internal protection but since they are high drain cells, the protection doesn't stop them from producing very high currents into a short. They meet the L3 standard for low resistance short circuits but that includes >200℃ and smoke, and it's time limited.

A short circuit or other unintentional low resistance connection across the battery has the potential to cause severe injury and very hot fires. Because of this, Samsung provides a warning printed directly on the cell when they are sold at retail...

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And, the 18650 Battery Store Listing includes an extensive set of cautions passed on from Samsung, according to Samsung policies (though I suspect they wouldn't need that to include them considering their own legal exposure as the seller). You can see the list on the site, but along with the general warning, it includes a couple of salient bullet points...

[...]
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But, it seems, reading comprehension is not among the chief skills of people who buy these cells. Among the many positive reviews on the listing are some that can make you rethink any faith in humanity* you might retain. Here are some exemplars of the rocket science being done by some of the 18650 Battery Store's customers...

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...and there are more. I suspect that it's probably not a lack of reading comprehension but instead a lack of respect for the energy these batteries can store. It's a sense of "that's just something lawyers made them say", and of knowing better than the scientists and engineers who made these things. Just like the person who gets seat belt religion after being in a collision, these folks won't take safety seriously until they are the ones appearing on the news, or have a close call.

I am not sure what we can do about this. The "We never wore seatbelts when we were kids and nothing happened to us!" mentality is irrational. Of course something happened to "us", just not to the person scoffing at safety measures. The willful ignorance combined with no—or a confused—understanding of probabilities makes such people immune to rational discussion.

But, these cells, and the batteries made of them, are dangerous when misapplied or mishandled. Like driving under the influence, it's not just a personal choice to accept risk—it puts others who did not choose it in danger. One of the difficulties is that the percentages involved are low, and this makes it seem "safe". The trouble is the absolute numbers are still high and even if the risk seems low, the hazard is severe and the potential outcome—no matter if it is only once out of ten thousand (for example)—is both extremely grave and not restricted to the person who chose to ignore the warnings.

This video has some good information. And, while the UL test involved disabling safety mechanisms, that's the point...

And while that was staged, there are many (many) cases that are organic...

(this is not political, please don't make it so)

the possible outcome, and the seatbelts after the collision mentality

another one

one, very sad, last one—from other sources, the shop had very poor safety practices when charging​

and, this panel discussion by firefighters is informative, if long.

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You can find many examples of fire videos on YouTube, and the more spectacular ones are all over the news, so why are people ignoring the danger? I don't feel I have any definitive answer to this, but I think there are probably many contributing factors whose superposition add up to the perfect storm of stupid behavior. It doesn't take a stupid person to make this mistake, but it does take education to fix it.

When I was growing up, in the 60s, there were many campaigns targeted at children concerning things like ecology, smoking cessation, gender equality, and racial prejudice. My experience is that I internalized those messages, and people of my generation did so in general. A focus on messages about sane safety measures and critical thinking about it as a part of being a smart adult would probably go a long way to help with this.

But there is a confounding factor I fear is going to be hard to walk back. The idea of "questioning authority" is a powerful and essential one. It should be part of everyone's philosophical toolbox. It keeps us safe from deception and even tyranny in the extreme case. But, the appearance of the method is not the same as the practice. What people claim is skepticism is, in the current environment, almost always something else.

It involves rejecting some authority whose conclusions are unacceptable in favor of one that comports with our own prejudice and desire. But that alternative authority will not be questioned at all. It also involves a strange belief that we can read the work of experts and somehow reject their conclusions even if we only understand a fraction of the evidence and rationale. "Internet research" can be very powerful if it involves actually understanding the material that is found, or it can be nothing but a way to justify a preferred outcome if evidence is cherry picked and misused with a faulty logical framework.

In any case, the very difficult work of vetting an expert in a world of growing specialization and sophistication isn't something a non-expert can do. The best we can do is to evaluate the case made by other experts in the field under examination and use logic that doesn't depend on subject matter expertise that we don't and can't reasonably possess.

But, this requires that we accept ambiguity and face our own ignorance. Often, this is not something people can or are willing to do. We live own a world where deontological systems are considered inherently superior to consequentialist ones by the majority of people. Where "gurus" are something people believe in, and where people are happy to surrender their agency while shouting that scientific consensus is nonsense.

Pragmatism, part of the possible rescue of our world, is vilified on all sides as "unprincipled" and not even considered because the word has become contaminated by libelous and self-serving rhetoric by those folks who benefit from (the appearance of) idealism. This has nothing to do with "intelligence". Some of the smartest people in the world fall prey to this, their intelligence does not provide immunity to the endemic cognitive bias that is part of being human. If anything, high intelligence makes it much harder to escape the carefully constructed personal mental prison we are each at risk of building to defend our prejudices.

So, what is the solution to the Lithium cell problem? Certainly not one thing. Education first seems prudent. Sensible regulation also seems appropriate. It might also be that civil or even criminal penalties for those who ignore the warnings and go on to cause personal injury or property damage due to the negligence may be warranted.

But, for the latter, the former—education—is a necessary prerequisite. People must be given the chance to understand the potential danger of their actions before being held accountable for them. The combination of education and regulation might make that practical. I hope something happens, though, because battery power is not going to be less common for high-energy human activity, only more.


*I'm not a misandrist by any stretch but it does strike me that these reviews all appear to come from male humans. I don't think this is something about the nature of men, but I do think it is a symptom of how men are nurtured by society. I really wish it was possible for people to examine these things, but they are so foundational they can't be seen to be questioned—they just appear to be "how things are".

 

People have accepted the risk of battery fires because of the value they add to their normal daily lives. Our (users and regulators) daily experience with batteries and charging systems for batteries, has for over a century been an safe one (mainly due to limited energy density of the batteries in most cases) so the inertia to a change in the perception of deadly risk is understandable. We don't ban having matches and lighters by the billions, being carried in the pocket everyday by millions, driving cars loaded with flammable fuels while smoking because we accept the risk of that too.

 

People have accepted the risk of battery fires because of the value they add to their normal daily lives. Our (users and regulators) daily experience with batteries and charging systems for batteries, has for over a century been an safe one (mainly due to limited energy density of the batteries in most cases) so the inertia to a change in the perception of deadly risk is understandable. We don't ban having matches and lighters by the billions, being carried in the pocket everyday by millions, driving cars loaded with flammable fuels while smoking because we accept the risk of that too.

I agree. We have to learn to live with the risks that normally come with new technologies that improve our quality of life. The AC/DC current wars come to mind ...

 

Our only hope is that they die young, before reproducing.

 

I agree. We have to learn to live with the risks that normally come with new technologies that improve our quality of life. The AC/DC current wars come to mind ...

I think electric vehicles are great stuff. Quiet, non-polluting at the point of use, and simpler than ICE-powered alternatives. But if the while we do live with acceptable risks from technology the rub is what “acceptable” means. In the cases where the risk is endemic to the technology we have to decide whether the cost-benefit is favorable.

Frankly, we are not always very good at that, and the poor decision making can be helped along by people and corporations with a vested interest in the adoption of the technology and no particular interest in the common good except where it affects their bottom line. If they can engineer a situation where adopting the technology isn’t really optional (see the history of the automobile in the US), and manipulate laws with regulatory capture, the decision can effectively be take out of “our” hands.

In the automobile example, the proliferation of cars in the street lead to a massive increase in deaths and injuries. The car makers took many steps to ensure the car would replace people, public transportation, carts, and all of the traditional use of the street because it was incompatible.

They did things like buy up and shut down the street car lines so people were forced to buy cars if they wanted to live outside the city proper. They invented jaywalking and used it to blame the victims of cars driving on the streets that were actually made for people. They did a lot of other things, too.

It didn’t have to go that way, see the Netherlands for an alternative. Cars on the street were rejected there and an alternative solution was developed. It was literally outraged mothers who didn’t want to see their kids being killed that refused to allow the takeover of the street. Today, you can drive in the Netherlands as you can here—but you do it on roads for cars. not the street that was intended for people and slow moving vehicles.

My fear is that rather than take sensible measures including regulation and education, the large amount of money to be made will drive vested interests to take similar steps to what the car makers did forcing the technology on the public in a much riskier form than is necessary.

 

People have accepted the risk of battery fires because of the value they add to their normal daily lives. Our (users and regulators) daily experience with batteries and charging systems for batteries, has for over a century been an safe one (mainly due to limited energy density of the batteries in most cases) so the inertia to a change in the perception of deadly risk is understandable. We don't ban having matches and lighters by the billions, being carried in the pocket everyday by millions, driving cars loaded with flammable fuels while smoking because we accept the risk of that too.

But that’s my point. People haven’t really accepted a battery fire happening to them. They‘ve accepted it happening to someone else. The current state of the art in Lithium-power consumer goods runs from very safe to ”ticking time bomb”. The early mistakes by Samsung and others lead to the rapid development of safer versions of the technology.

Today you can carry your phone with almost no concern at all that there is a Lithium cell in it. But, you can’t do the same with your vape pen. Why is that? Because Samsung, et al, is willing to bear the cost in reduced profits and somewhat reduced sales caused by the slightly more expensive technology required.

The manufacturers of the vape pens are not willing to forego the profits and they must keep the costs down because of the extreme price sensitivity their practices have bred. This is one of the advantages of a regulatory approach. It sets a baseline, and it means that if you need to lower your price you are going to have to do it somewhere other than in safety mechanisms.

As far as matches and lighters, and smoking in cars, neither of these things pose much risk at all. Lighters don’t suddenly and without apparent reason burst into flames and explode, nor do matches. Smoking materials in the passenger compartment of cars don’t pose a risk worth worrying about in relation to the fuel system. If lighters exploded at random and a cigarette could ignite your gas tank, there would be a hue and cry to change that—like there should be about the vape pens and electric vehicles.

Things don’t have to be as risky as they are. It’s not the technology, it’s the social and commercial aspects that are driving that risk. We know how to manufacture safe versions, that we are not is what needs addressing not how to push the cost of the unsafe products onto society in general and people not using them.

 

Which is why the FAA bans Li Ion batteries from being brought on board airlines except in certain approved devices. Asia is currently experiencing many fires in both cars and electric two wheelers. Even here in the US many parking garages and multi apartment buildings are banning electric cars, scooters, and bikes indoors. Hydrogen is being touted as a better solution but from my experience with hydrogen it really scares me to think about it in a vehicle. Propane wasn't so bad but hydrogen? When hydrogen is released from pressure the change in energy is often sufficient to ignite it unlike most flammable gases. The Air Products truck drivers who delivered hydrogen to our plant told me that hydrogen fires were very common on their trucks.

 

Which is why the FAA bans Li Ion batteries from being brought on board airlines except in certain approved devices. Asia is currently experiencing many fires in both cars and electric two wheelers. Even here in the US many parking garages and multi apartment buildings are banning electric cars, scooters, and bikes indoors. Hydrogen is being touted as a better solution but from my experience with hydrogen it really scares me to think about it in a vehicle. Propane wasn't so bad but hydrogen? When hydrogen is released from pressure the change in energy is often sufficient to ignite it unlike most flammable gases. The Air Products truck drivers who delivered hydrogen to our plant told me that hydrogen fires were very common on their trucks.

Unfortunately, Hydrogen is DOA as a fuel for transportation. The economics don’t work, and there are too many technical problems. Battery-powered vehicles make the most sense, but we will either have to move to something like LiFePO4 which is inherently safer or find a way to make conventional Lithium cells that doesn’t require a flammable electrolyte.

Since we don’t seem to be able to count on even having the known, working safety measures in place for the current cylindrical and prismatic cells it seems that only an inherently safe solution is ultimately workable.

 

In a country that has more guns than people, batteries is not the problem.

 

But that’s my point. People haven’t really accepted a battery fire happening to them. They‘ve accepted it happening to someone else.

That's the 'reptile' (primitive and animalistic) brain response to personal danger in general until the threat is imminent and directly on you. The guy next to you in the foxhole will get the random bullet in the head, not you, so I'm not surprised.
I think the current regulatory response to the battery risk is typical for the actual dangers presented when blended with the risks the public perceives daily in general.

As we discovered during the COVID response, safety has a cost (many times unforeseen) even with the best intentions.

https://www.nytimes.com/2023/09/05/briefing/covid-school-absence.html/
Where Are the Students?

For as long as schools have existed, so have these morning struggles. Nonetheless, children overcame them almost every day, sometimes with a strong nudge from parents. Going to school was the normal thing to do.

Then, suddenly, it wasn’t.

The long school closures during the Covid pandemic were the biggest disruption in the history of modern American education. And those closures changed the way many students and parents think about school. Attendance, in short, has come to feel more optional than it once did, and absenteeism has soared, remaining high even as Covid has stopped dominating everyday life.

 

Excellent post!

What I find horrifying is the public's general lack of understanding about what "energy" is.
The consumer demand for more and more battery capacity ignores the inherent and unavoidable risks associated with concentrating all that energy into a small item.

The average consumer barely comprehends the relative amounts of energy that appliances consume.

 

What I find horrifying is the public's general lack of understanding about what "energy" is.

This: