Are all portable USB battery pack chargers ("power banks") LiPo?

[John Eucist]

So I bought this USB battery pack charger ("power bank") before I noticed it says "Lithium-ion polymer" on it.  AFAIK LiPo is dangerous compared to normal "Li-ion" batteries.  Are all these power banks always LiPo or is this one unique?

[Gimlet]

I believe most phone batteries and boosters are lipo due to the higher power density and the fact that they are expecting a much gentler existence as a phone charger than our euc batteries get.

[John Eucist]

I believe most phone batteries and boosters are lipo due to the higher power density and the fact that they are expecting a much gentler existence as a phone charger than our euc batteries get.

I went and checked all my other "power banks" and none of them even bothered to STATE if it's Li-ion or LiPo (perhaps intentionally).  So perhaps they are all LiPo and only this one actually cares to state it on their package.  If anyone else knows with more certainty please chime in.

[Jason McNeil]

From my understanding, LiPos are considered reasonably safe in applications like mobile phones/laptops, etc; the risks increase exponentially when there is serialization (connecting multiple packs together) to yield the voltages needed in an EU. Because they lack the intrinsic safety elements of the 18650 cyclindricals, are more susceptible to catastrophic failure; with a 400Wh pack, this is a huge amount instantaneous energy. Consider that the a 9mm pistol bullet has 519 joules, which is only 0.1441Wh, this 400Wh battery therefore contains the energy of 2775 9mm bullets!!! 

https://en.wikipedia.org/wiki/Lithium_polymer_battery

Compared to cylindrical Li-ion cells, LiPos lack integrated safety devices such as a current interrupting device (CID) or a positive temperature coefficient (PTC) material that is able to protect against an over-current or an over-temperature

[esaj]

with a 400Wh pack, this is a huge amount instantaneous energy. Consider that the a 9mm pistol bullet has 519 joules, which is only 0.1441Wh, this 400Wh battery therefore contains the energy of 2775 9mm bullets!!! 

 

Maybe a better comparison is TNT (dynamite). 1 gram of TNT contains about 4184 joules,  1 Watt hour = 3600 Joules, so a gram of TNT ocntains about 1,162222... Wh.

So 400Wh / 1,16222... Wh/gram of TNT = about 344 grams (0,344kg) of dynamite. You probably don't want that to go off near you    Here's some facts of 1kg of TNT:

 

[Jason McNeil]

Why is a it 'better' comparison? What's impressive about the number of bullets, is most people assume a bullet contains much more energy than it in fact does.  

[esaj]

Why is a it 'better' comparison? What's impressive about the number of bullets, is most people assume a bullet contains much more energy than it in fact does.  

Well, I said "maybe", but I thought it's easier to imagine the power of a battery explosion if the power is compared to a typical explosive, and "TNT equivalent/Relative effectiveness factor" is the typical way of comparing explosives.

TNT equivalent is a method of quantifying the energy released in explosions. The "ton of TNT" is a unit of energy equal to 4.184 gigajoules (1 gigacalorie), which is approximately the amount of energy released in the detonation of a ton of TNT. The "megaton of TNT" is a unit of energy equal to 4.184 petajoules.^[1]

The relative effectiveness factor, or R.E. factor, relates an explosive's demolition power to that of TNT, in units of the TNT equivalent/kg (TNTe/kg). The R.E. factor is the relative mass of TNT to which an explosive is equivalent; the greater the R.E., the more powerful the explosive.

Although, I don't know if the batteries can actually release their energy that quickly, so it's more likely just to catch fire than actually explode like a real explosive.

[Gimlet]

With a bullet Jason the entire force of energy released by the charge is concentrated by the barrel onto the rear of the bullet head and little force is wasted until it reaches the end of the barrel.

That's a lot of force to exert on an object weighing maybe 120-150 grains. Then again my .308/762 rifles put a hell of a lot more force behind a similar weight bullet through a much longer barrel, I use 155 grains for targets out to 1,200yrds and very fast flat shooting 123 grain expanding bullets for hunting.

[Jason McNeil]

Yeah, even in the worst-case scenarios, like puncturing a series of battery pouches, the footage I've seen on YouTube shows a vigorous exothermic reaction but over a couple seconds. Explosives release all of their energy in microseconds, which is why they're so destructive.  

With a bullet Jason the entire force of energy released by the charge is concentrated by the barrel onto the rear of the bullet head and little force is wasted until it reaches the end of the barrel.

Concentrated or not, the point is still that it's energy unit equivalents. 

[Chuts]

Seems I'm late to this party by a few weeks but... from times past while looking into batteries it seems that they are practically the same thing.  Only the type of chemistry they use to store energy is the main difference.  Liion uses a solid chemical to store energy and is usually sold in a cylindrical format.  Lipo uses a polymer and is flexible and allows it to be molded into different shapes.

For the same mass you can usually store more energy into a Lipo.  Therefore it can also release a lot of energy at once too and I believe it also stays at the nominal 3.7 voltage longer than Liion.

[John Eucist]

Seems I'm late to this party by a few weeks but... from times past while looking into batteries it seems that they are practically the same thing.  Only the type of chemistry they use to store energy is the main difference.  Liion uses a solid chemical to store energy and is usually sold in a cylindrical format.  Lipo uses a polymer and is flexible and allows it to be molded into different shapes.

For the same mass you can usually store more energy into a Lipo.  Therefore it can also release a lot of energy at once too and I believe it also stays at the nominal 3.7 voltage longer than Liion.

After seeing so many recent Li-ion battery explosion and fire videos I think Li-ion and LiPo is the same basic shit and dangerous.  Governments should seriously consider making everything go LiFePO4 until an even safer technology can be mass produced.  Of course energy density will suffer but it's a compromise needed for safety.

[Chuts]

@John Eucist I thought explosions occur mainly because of damage due to user neglect?

[John Eucist]

@John Eucist I thought explosions occur mainly because of damage due to user neglect?

Could be battery short, bloated battery from overcharge, overheat, puncturing, or whatever.  The fact that a small mobile phone sized battery like this can do this makes you wonder what 64 cells of 18650 (for example my 680 Wh GW14) can do.

 

 

[Chuts]

@John Eucist Thats what I mean about user neglect.

This is for people who are not too sure regarding batteries and their use.  Using some of John's examples for what can go wrong.

• Battery Short - Usually due to aging equipment.  For example someone using the same battery for 5+ Years without changing them.  That the parts ware out from use and degradation.
• Bloated Battery - Usually with Lipo batteries as they are mostly supplied in pouches.  They need a hard container surrounding them to stop the expansion.  Again charging them and neglecting them when they have become fully charged.  If leaving unattended buy a Lipo charging bag or fireproof container.  Much cheaper than having your property burn down or personal injury.
• Overheat - Mainly due to using the same batteries constantly without rest.  Charging then using, charging then using and so on.  Have a second battery and work them in a rotation.  The more battery packs you can fit into the rotation the better.  If you can't change the battery then make sure you give it time to cool down.
• Puncturing - Apart from doing it on purpose.  You should inspect products carefully and properly after dropping them, in cases like mobile phones or in an EU scenario, crashing them, make sure batteries are not damaged from objects that may have pierced the shell.  Worse for Lipo, as mentioned they are usually supplied in a soft pouch form and can be easily pierced.  Liion as you may already know have hard casing to protect them, but with enough force even they can be pierced.

Batteries can be very dangerous, so look after yourself by looking after them.

[Jason McNeil]

Li-ions from a reputable manufacturer that have gone through proper QC processes, with PTC and/or CID are pretty much as-safe-as-you-can-get. These are tested in 140° ovens, overcharged to many times the rated voltage/amperage (20V/20A), shorted-out & go through a battery of tests to ensure they will self-destruct harmlessly.

Jumping to the conclusion that LifePo4 is the only safe chemistry, is in my opinion, a bit of an over-reaction. 

Example of the LG HE2 tests http://www.powerstream.com/p/LG-ICR18650HE2-REV0.pdf

Similar for the Samsung 25Rs http://www.powerstream.com/p/INR18650-25R-datasheet.pdf 

 

[esaj]

Li-ions from a reputable manufacturer that have gone through proper QC processes, with PTC and/or CID are pretty much as-safe-as-you-can-get. These are tested in 140° ovens, overcharged to many times the rated voltage/amperage (20V/20A), shorted-out & go through a battery of tests to ensure they will self-destruct harmlessly.

Jumping to the conclusion that LifePo4 is the only safe chemistry, is in my opinion, a bit of an over-reaction. 

Example of the LG HE2 tests http://www.powerstream.com/p/LG-ICR18650HE2-REV0.pdf

Similar for the Samsung 25Rs http://www.powerstream.com/p/INR18650-25R-datasheet.pdf 

 

Love the terms in testing, "Electrical abuse", "Mechanical abuse", "Thermal abuse".   But those tests are really rough, way beyond any normal use. For example, discharge 95A 0.5s - 80A 0.5s 45A 5sec, 30A 6s, 12s rest, continue for 100 cycles, or charging at 3 * the maximum charge current for 7 hours straight, external short circuiting fully charged battery for 1 hour straight, heating to 130C... 

Makes me think  that there either has to be really something wrong with the cell or the wheel before it would catch fire or explode (like in the video in "euc on fire"-topic), if using high quality cells. The chinese "noname"-cells could be a different matter (wouldn't be that surprised if they blow up all by themselves ). Saving in the wrong place can be really dangerous, better think twice before buying those cheap portable battery packs or noname "high capacity" replacement laptop/cellphone batteries...

[Chuts]

You should watch the new Battlebots... Some Lipo batteries are shredded and there isn't even an explosion.  Especially in Episode 4 - Tombstone vs Radioactive.  You see one Lipo being knocked out and smashed across the arena floor yet no explosion.

https://www.youtube.com/channel/UCRRCB3jKyvhoDscWknafPng