BBC: Li-ion battery may not have overheated in Dreamliner

Lion batteries are safe as long as they are properly cared for. Not over charged, or under charged, or over heated. Any one of those three can cause the battery to rupture and flame. They are a whole lot safer than Lipo batteries though. Nick a case on one of those packs so air gets in and kiss it and whatever it is in or near goodbye.

I fly Electric power RC planes and use both Lion and Lipo packs in them, and only had an issue with one, thankfully it was nearly depleted and only a 1S 250mah pack, it shorted on a crash and puffed up and got hot, but didnt burst.

Key is to maintain the proper charge/discharge levels and temps and these batteries are fine. Most likely the cause of that incident is directly related to the power level management system and not the batteries.

 

I'll second this as everything I've read indicates battery management is the key. But the higher energy density is so attractive it just makes sense to spend more time doing and testing the whole system.

I will need a starter battery for my plane and already there are off-the-shelf LiON/LiPO starter batteries available. Many have seen service in motorcycles so we're not talking about totally untested technology. Just it is different and that is what folks have to get used to.

Bob Wilson

 

Li-cobalt in the Dreamliner


Li-NMC in PiP


Source

 

I was recently thinking that I didn't like Li Ion in general as it fails too fast in my personal experience. (2 years in cordless screwdriver, ~3 years in JVC camera, 3 years aftermarket for same camera, etc. All with light use).
But I did forget about my laptop battery which still has (estimation) ~75% capacity left after >5 years of use

But indeed, as stated: battery management is probably half or more of the equation...

(PS also just remembered I recently put a 23 (!) year old lithium AA-sized cell (3.6V) into my daughter's LED-bicycle rear-light. OK, so it's not rechargeable, but still quite impressive)

 

And there is the problem. If the packs sit for any length of time with a full or depleted charge in them, they fail after a certain period of time. However, if you shelve them with a storage charge, which on a Lipo is 3.8v per cell, shelf life is virtually limitless.

One thing you never want to do is store the pack in the device for any length of time unused, that does the most damage to them. I recently acquired a few RC airplanes that the Lion packs were left connected, and never fully cycled or set to storage charge, they were ruined, and started to leak. There was also a Lipo that was severely puffed up from being discharged.

 

Two terms will get mixed into this discussion:

Li-Po, Lithium Polymer, which is more a construction than a chemistry, usually used to distinguish from the original Li-Ion construction, though both are really lithium ion;

LiFePO, Lithium Iron Phosphate chemistry, as opposed to LiCo or LiNMC (nickel manganese cobalt) or several other varieties.

 

I thought the bbc article said the batteries were not over charged, meaning the specs on the batteries are wrong or there is a manufacturing defect.
Dreamliner Probe Turns to Battery Maker - WSJ.com

 

Maybe due to cosmic ray.

 

So we're looking at the charred remains of the battery and it didn't overheat? What planet do they live on!
Boeing let the smoke out! It's not the first one, it's not the last one, which is the reason they are grounded!
Time to invest in "proper" charge and temp control electronics! Whatever that is or needs to be.

Yes, the NiMH battery cell has a lot going for it, though I agree energy density is not one of its' better attributes.

 

The only thing the investigators have said is that the battery was not charged at too high a voltage for its spec. That means the charging electronics are not at fault. It could be the battery, or it could be that it was discharged too quickly. They are looking at everything, but right now it seems the focus is on the battery itself.

There are normally at least 2 fail safes. I'm sure boeing did invest in electronics. GS Yuasa has never had a aircraft battery before.

Why do you think nimh would be better? This is a brand new design, and they are replacing hydraulics with electronics. Let's let the investigators investigate. THe way back is to add the weight of hydraulics. No one wants nimh in the planes. Airbus is lucky that they get to watch and adjust their Li battery/electronics based on the investigation. Boeing and JAL are very lucky no one got hurt.

 

The local news, here in Boeing's back yard, is that the JAL battery in Boston was not subjected to overvoltage. The ANA battery in Japan has not yet reached the same level of investigation.

My memory of earlier reports is that both are the same battery model, but but at different locations in the plane. JAL at the rear, ANA at the front?

 

Thank you USB these are good references I am saving them. But these plots do not seem to explain why anyone would use the Li-cobalt. I assume it is smaller size per energy stored and that's important for aircraft/phone design?

 

Do you have a reliable source that the Prius plugin cells use NMC cathodes?

I haven't seen anything definitive about the Prius plugin battery chemistry. Panasonic's newest and most advanced cylindrical cells that are publicly documented and available for general sale are NCA however Panasonic is known to be working on "Sanyo Y" cells which use blended LMO/NMC cathodes (like the Chevy Volt, reportedly).

NCA is generally considered somewhat safer than Lithium Cobalt cells but less safe than LMO, LMO/NMC, or Lithium NMC cells.

 

I think Li-Cobalt has the highest energy per weight, though the spider charts put them equally. Perhaps the difference is slightly different.

Another reason to pick Li-Cobalt may be due to slightly lower production cost since most of the consumer electronic batteries uses it.

 

NMC (Sanyo) according to Dr.Anderman (see page 42). Can you share your source that said "Sanyo Y" cell has LMO mixed?

AESC (Nissan Leaf) battery is said to be LMO+NCA.

 

Ok, yes I see that now. That's very suggestive although it does not explicitly say that the 2012 production plugin Prius is using the NMC Sanyo prismatic cells listed in the table. I'm willing to believe that until better evidence comes along.

For "Sanyo Y", see the 3 energy.gov reports that come up from the google search below.

Google: "sanyo y" nmc

 

This one? It is 18650 laptop battery size though. 1900mAh is lower than the ones used in Tesla Model S (3.4 Ah).

Here, Dr.Anderman said Sanyo HV cells are using LMO/NMC. He didn't specifically say the PHEV cells that Sanyo was working also use LMO/NMC.

The info on HV cells seems to be conflicting.