This seems to be a more and more common subject for the J school graduate crowd.  Unfortunately, not all articles dealing with the danger of eBike battery fires are without some substance.  The problem is real.  Thermal Runaway is a problem with any lithium battery chemistry.  The casual J school graduate article on the subject usually fails to differentiate in his or her discussion the subtle and not so subtle differences in safety from one type of lithium battery chemistry to the other, most of the time they ignore the fact that those differences in battery chemistry are even important.  Their impetus seems to be that of painting the whole subject of lithium battery fire safety with a single broad brush and ignoring the "details".

Well, those details are important and there are vast differences in both fire safety and performance from one lithium battery chemistry to another.  The safest lithium battery chemistry, as related to the problem of lithium battery Thermal Runaway, may be Lithium Titanate, but more about that later.

The latest attack on lithium batteries for eBikes comes from the National Renewable Energy Laboratory:

Why the US's main sustainable energy center just banned e-bikes (electrek.co)

NREL Has Just Issued A Ban On All E-Bikes And E-Scooters – Here’s Why (insideevs.com)

OK, so what about painting with a broad brush as in the ban of "All E-Bikes"?

Take a look at one of the chemistries that has been considered much safer for over a decade or more.  Lithium Iron Phosphate.  I have 2 of these LiFePO4 battery powered E Bikes in my garage and in general they truly are much safer regarding the issue of Thermal Runaway, Fire and Explosion.  However, they are not exempt from such untoward events.

Some general information about E Bike safety and E Bike battery fires:

E-Bike Battery Safety And Fires | Electric Bike Report | Electric Bike, Ebikes, Electric Bicycles, E Bike, Reviews

E-bike fires: why they happen, and how you can prevent them | TechRadar

So, does using the more common type of E Bike battery, LiFePO4, buy you immunity from this tragic problem?  Well, the quick answer is:  No. 

See this abstract from The Journal of Energy Storage for October, 2020:

Thermal runaway and fire behaviors of lithium iron phosphate battery induced by over heating - ScienceDirect

So, they do occur even in the generally viewed safer form of Lithium Iron Phosphate batteries.  You still have to be mindful with this type of lithium battery chemistry, though they do provide a safer alternative compared to some of the other lithium battery chemistries out on the market.  But are there still safer lithium chemistries available to the consumer vs lithium iron phosphate?

Patience, Grasshopper.  Let's first examine the problem as related to lithium iron phosphate chemistry in a little bit deeper detail, there is that word again: "detail".  Be sure, by the way, to pay particular attention to the chart in the article linked below with the word "Cleversolarpower.com" above the chart and located under the subtitle:  "Overcharge:". 

Notice the section of that chart colored in Green.  That corresponds to the 20-80 "Rule" for charging lithium ion batteries in order to preserve cycle life of the battery.  They flat last longer if you don't allow them to fall below 20% SOC or to rise above 80% SOC, SOC being the State Of Charge.  Charging above 80%, for instance, requires more energy to force that last 20% of energy into the storage of the battery and thus generates more heat during that process so it is quite possible that the 20-80% Rule, if diligently observed by the consumer, will not only increase the life of the battery but also increase the safety factors involved as well. That goes for any lithium battery chemistry, not just lithium iron phosphate batteries.

 Are Lithium Iron Phosphate (LiFePO4) Batteries Safe? A Comprehensive Guide (cleversolarpower.com) 

OK, you have patiently ground through all of the verbiage above and possibly even looked at one or even two of the links provided, so where is the icing on the cake, eh?  Some lithium battery chemistry that is even more safe than the LiFePO4 battery chemistry.

Lithium Titanate.

Keep in mind that I am only providing a sampling of the differences in lithium battery chemistry.  Those who paint all lithium battery chemistries with the same brush do a disservice to the reader.  If you start looking for this broad brush journalistic treatment of a complex subject you will discover rather quickly that most authors of articles, especially those that feature the problem of actual Thermal Runaway situations, never even bring up the subject of distinguishing between the different types of lithium battery chemistries.  They treat all lithium batteries as if they came from the same mold. 

Think of it this way:  If an author decided to write an article on cars and treated the Yugo or the new Russian "Amber" in the same manner as the Maserati then how much would you value the conclusions of that author regarding the entire subject of "Cars"?  There are big differences from one end of the scale in that subject to the other end of the scale.  The same big differences apply when dealing with the subject of lithium batteries.  One size shoe doesn't feet all the different types and sizes of feet.

Just a quick aside regarding that new Russian "Amber":  This Russian EV Looks Absolutely Ridiculous (motor1.com)

Comic relief now finished and back to the main topic:  Lithium Titanate batteries:

Move Over Lithium-Ion—There's a New E-Bike Battery in Town (powermag.com)

Lithium-titanate batteries: Everything you need to know (climatebiz.com)

For the "Techies" (Full Disclosure:  I am NOT a "Techie", far from it!), this more technical view of Lithium titanate batteries should be of interest:

Lithium Titanate (LTO) Cells - Technical Advantages | GWL Group

OK, that concludes my foray into the subject of Lithium Battery Safety... and I didn't even broach the advantage of solid state batteries vs those with liquid or gell electrolytes. 

Like I said in the beginning:  A broad brush approach to talking about lithium battery safety is simply an indicator of sloppy journalism.  Be on guard for those who weld the broad brush when reading about their take on the safety of lithium batteries. 

If they don't at least give some basic lip service to the diffeences from one type of battery chemistry to another then avoid their conclusions and their article.

Onward through the FOG!

Okiedo