More Bad Press for Lithium Batteries

[Michael]

Lithium Batteries seem to get such a bad press for their use in Garden Railways. You get the forums with their exploding battery videos and scare stories and now in the latest publication from the U.K. based 16mm Narrow Gauge Modellers Society, "The Guide to 16mm Scale Modelling", you get the following in the 'Loco Control' section:

"Li Po batteries are also available, but are definitely avoided by anyone considered less than an expert. Speak to loco manufacturers who have experimented with this battery type and you'll get horrible stories of how they gave up with Li Po after blowing things up."

So what if we did take a modern Li-Ion cell and abuse it like in the vidoes and scare stories? Well a few years ago whilst selecting a suitable lithium battery for my locos I came across the following test report for the Samsumg 30Q 18650 Li-Ion cell that I eventually choose and are in several of my locos.

https://eu.nkon.nl/sk/k/30q.pdf

To summarise, various test are performed on the cell and the results are compared as follows:


As for the tests, well all those that proliferate the fear factor:

Overcharge: Connect to a 20 Volt, 20 Amp power supply for 30 minutes (normally 4.2 volts)

Short Circuit: 10mohms at 23°C for 120 seconds

Temperature: Hot oven, 140°C for 70 minutes

Mechanical abuse: Massive dent in middle of cell

The results for the 30Q are as follows, all at level 1 or below, no exploding batteries. Yes they get hot, maximum temperature 128°C (overcharge), 87°C (short circuit).



Of course with an appropriate protection board, required by these batteries and a fuse to suit the current requirements of the loco, the above situations won't occur.

Perhaps they are not so bad after all.

Posted for information only, not to start a heated debate on the pros and cons of lithium batteries

Michael

 

[Greg Elmassian]

Interesting how the watt hour capacity at 1c (3 amps) is almost the same as discharging at 20 amps.

Samsung seems to be the industry standard for larger packs.

It takes a lot to have these cells cause issues, often it is a short circuit that starts a fire, not really the battery.

Greg

 

[stockers]

Chalk and cheese - The report seem to have jumped seemlessly from Li-pos to Li-ions. They are very different. Li-pos get hot and expand and then leak and then catch fire if you over charge them, Li-ions are rather more stable in this situation - as stated above.

 

[dunnyrail]

Chalk and cheese - The report seem to have jumped seemlessly from Li-pos to Li-ions. They are very different. Li-pos get hot and expand and then leak and then catch fire if you over charge them, Li-ions are rather more stable in this situation - as stated above.

Well said Alan, most of us probably have Li-ons in our phones, iPads and many other things. Not sure how many use them in Dead Rail conversions, would be interesting to know.

 

[Greg Elmassian]

you will find that virtually all modern cell phones have li-po batteries

 

[PhilP]

Well said Alan, most of us probably have Li-ons in our phones, iPads and many other things. Not sure how many use them in Dead Rail conversions, would be interesting to know.

NO!

In order to get them thin enough, and in the form-factor needed, they are nearly ALL Li-po batteries. - Flexible 'pouches' that can be folded into small spaces.

Hence my saying that many people carry one about, close to parts they hold dear!

Then they stuff 'em in a back-pocket, and sit on 'em!!

But put them safely in a loco, and "Ooooh! No! The sky is falling in!!"


Overall, they are (if treated sensibly) no-more 'unsafe' than Lead-Acid, Gas, Spirit, even Coal (cinders, sparks)..

 

[dunnyrail]

So to get this clear a Li-Ion is a LiPo in a different plastic box? Probably not quite so, but some of the tech reading in the 2 links below may help understanding. The third link is just one of probably lots of sites talking about safety of the two types.

Audrey Victoria Li-Po vs Li-ion battery,what are the difference bet...

The history of lithium polymer batteries dates back to the 1970s. Their first design included a dry solid polymer electrolyte similar to a plastic film. Therefore, this type of battery can achieve a very thin design while still maintaining a relatively good battery life. In addition, lithium...

www.ovonicshop.com

Li-polymer Battery: Substance or Hype? – Battery University

Find out what made lithium-polymer battery systems popular. Most users cannot distinguish between a regular Li-ion and one with polymer architecture.

batteryuniversity.com

How safe are the batteries (Lithium-Ion/Li-Po) in smartphones and tablets?

How safe are the batteries (Lithium-Ion/Li-Po) in smartphones and tablets? After the continuous barrage of the Samsung Galaxy Note7 fiascos, now more than ever, people are afraid of their smartphones exploding. While this type of an accident may seem unlikely, it’s important to unde

www.fixez.com

This is not a simple matter, just look at the mess that Samsung got themselves into and also Boing Dreamliner's with their well published Battery Fires.

I know this thread was started in a manner that hoped would not get into a discussion of what is best or worse. Thus I have not commented but given links to allow reasoned self learning and views to be taken.

Believe me there are acres of discussion on the merits or not of both types!

 

[PhilP]

So to get this clear a Li-Ion is a LiPo in a different plastic box?

No..

A Li-ion battery looks very like any other cell you think of commonly.. - It is 'just' a different chemistry inside.



Left to right:
A '3S' block of 18650 Li-ion cells, an Eneloop NiMH 'AA' cell, a 14500 Li-ion cell..

Note the 14500 cell is physically the same size as the 'AA' cell, but 3.77V (as opposed to 1.2V for the Eneloop). - The difference being the Li-ion cell has a 'flat-top' positive terminal, which is 'better' (larger surface-area) for making into packs / having tags spot-welded onto.

So the Li-ion 'cells' are a metal can, just like the Eneloop cell. - Both will vent if abused, by the 'gland' around the positive terminal.

Li-ion cells are more robust, as the outer is metal, and the internal construction is more uniform.

A Li-po cell is (basically) a plastic-pouch, with flexible electrodes (and separators).. These can then be 'folded' into different shapes, or rolled-up, to fit into a soft/hard outer plastic case.

Part of the 'problem' with Li-po's is this folding, as it stresses the construction, and quite often brings the electrodes closer together. - This causes a 'point of stress' in the package as a whole.


Does that help at all?

 

[stockers]

yes.

 

[GAP]

I have 2 LiPos and do not rapid charge them using a smart charger, subject them to physical abuse and have protection circuitry built into the motor drivers that will not allow over discharge.
I am quite comfortable with using them, although I do charge them uninstalled for added peace of mind, after looking at the way a friend who is an aircraft flyer treats his large collection, fast charge/discharge, I think my 2 have a very easy life.
I slow charge using a smart charger and slow discharge under load with the under voltage cutoff set at a level higher than recommended.
My batteries are commercially constructed and are not subjected to any folding or other modifications that change the construction configuration.
I make my own NiMH battery packs using tagged cells and again no modification of the shape takes place.
If you treat your cells/batteries with some respect and they will last for a long time, abuse them and they will turn around and bite you big time.
A large proportion of those videos on the net show people abusing their batteries and then saying "danger, danger".

 

[GAP]

Well said Alan, most of us probably have Li-ons in our phones, iPads and many other things. Not sure how many use them in Dead Rail conversions, would be interesting to know.

I do.
I have 2 in different locos, see my post in this thread about I treat them.
I think you will find that they are more prominent than you think.

 

[PhilP]

A large proportion of those videos on the net show people abusing their batteries and then saying "danger, danger".

A very good point...

Would anybody here, pop a spanner across a 12V car battery?
Would it be any less 'spectacular' than shorting a Lithium battery?

PLEASE! - If you are reading this, and think it a 'good-idea'.. DON'T!

(The problem with designing for idiots, is nature will always breed a bigger one!)

 

[Greg Elmassian]

One of the links above gave the best information, for all intents and purposes, todays li-po and li-ion are pretty much identical in terms of operation and capability.

li-ion does come in cylindrical cells, which can take more physical abuse than the "bag" type.

Very few model railroaders use the super fast charging rates that the model airplane guys do, like 10C.

So for use, it's what is convenient, and I would guess that the cylindrical cells, or the hard shell prismatic cells would be best just because of their added physical protection.

I see so many arguments that li-ion is good and safe and li-poly is bad and unsafe, and even vice versa. Electrically modern cells are basically identical.

Very few modern rechargable consumer devices do NOT have a lithium based cell. We just need to take more care, but as wisely stated earlier, it's in your phone, toothbrush, watch, computer, etc.

Greg

 

[The Shed]

A little surprised at this comment from the sixteen millers "Li Po batteries are also available, but are definitely avoided by anyone considered less than an expert. Speak to loco manufacturers who have experimented with this battery type and you'll get horrible stories of how they gave up with Li Po after blowing things up."

Never had an issue, common sense, and good practice to follow the manufacturer's advice on both the battery and the charger.



Bottom battery pack a follow on from this posting.
2 Steam Trams with Deltang Radio Control, My Loco Sound cards and LiPo Batteries. - G Scale Central

 

[PhilP]

Yes, I saw that comment, and it grated, a little!

 

[Paul M]

Could be something to do with the hot and steamy atmostphere? I dont know if that will affect them

 

[Rhinochugger]

Could be something to do with the hot and steamy atmostphere? I dont know if that will affect them

Wot, the 16 millers? Clearly has

 

[PhilP]

Yep!
No eyebrows..
No finger-prints..
Burnt trouser-legs (spirit)..



And that is before they start on Li-po batteries!

 

[Paul M]

Yep!
No eyebrows..
No finger-prints..
Burnt trouser-legs (spirit)

The marks of a real man (& woman)

 

[Northsider]

Now we are clearly into thread drift, can I ask Phil where I can buy a coal-fired mobile phone (post #6)? Sounds like my kinda thing! But then I have no eyebrows or finger prints and my trousers frequently catch fire!