USA tightens battery shipping regulations

[shemozzle999]

http://phmsa.dot.gov/hazmat/phmsa-issues-lithium-ion-battery-safety-advisory-related-to-air-transportation

 

[SteveRuss]

http://phmsa.dot.gov/hazmat/phmsa-issues-lithium-ion-battery-safety-advisory-related-to-air-transportation

It makes you wonder how safe these things are when totally flat (and I know that's not good for them). They say 30%. I wonder what maths that's based on..

 

[anotherkiwi]

They are very safe if you immerge them in salt water when flat then punch a hole through with a nail. That way they become completely safe and you can trash them with no risk of pollution...

 

[flecc]

It makes you wonder how safe these things are when totally flat (and I know that's not good for them). They say 30%. I wonder what maths that's based on..

Probably based on that being considered a good level for safe storage. A bit pointless though, since lithium battery fires and explosions almost always result from inadequate quality control in manufacture and can occur regardless of charge level.

Lithum doesn't and shouldn't exist in metallic form in cells, but under some poor manufacturing standards lithium crystals can form. These grow in jagged and irregular formations and can pierce cell internal insulations, setting up short circuits. The resulting heat swells the cell which can burst, spilling it's burning content. In the worst case, the cell can spread the damage to surrounding cells, causing the battery casing to swell and explode into a fierce fire.
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[mike killay]

Flecc,
Do you know what was the cause of the Belgian Post Office bike fires?
I see that they are back to non electric bikes now.

 

[flecc]

Flecc,
Do you know what was the cause of the Belgian Post Office bike fires?
I see that they are back to non electric bikes now.

I don't know the specific cause Mike, but can guess that it was almost certainly as I described since that is by far the most common cause.

There is an added factor I didn't mention above though, the constitution of the cathode. Worst for instability were the original cobalt cathodes, causing many fires. To solve that manganese cathodes were introduced but they reduced the battery performance, so some compound cathodes were developed containing several constituents. Cobalt has been reintroduced as one constituent to get the best performance but in some formulations might have started to cause problems. There are many compound cathode formulations, cell companies having their own developed favourites and constantly experimenting with new ones.
.

 

[mike killay]

Thanks Flecc,

 

[flecc]

Flecc,
Do you know what was the cause of the Belgian Post Office bike fires?
I see that they are back to non electric bikes now.

Battery fires aside, it could be they gave up on e-bikes for the same reason our Royal Mail gave up it's plans for 16,000 of them.

That was the rapid changes in the pattern of mail being delivered. They managed to cope with the huge increases in junk mail, but the measures for that couldn't cope with the numbers of packages which the huge growth in online sales had brought. That in bulk not only grew beyond what a postman could reasonably carry, but beyond what a trade bike could either.

The solutions I know of here have been in some cases box trolleys which the postman wheels along from house to house, or a system of dual manned van deliveries which has proved very efficient.
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