Lithium battery physical protection


#1

I’m building a portable electronics product that I want to have mass-produced and sold to consumers. Besides the obvious electronic protection (overtemperature, over-/undercharge), I’m worried about physical protection.

For example, it seems li-ion batteries can in rare circumstances swell up. Should I leave some extra space to allow the battery to swell and if yes, how much? I plan on covering all sharp edges (from through holes sticking through the pcb) so they can’t cut the battery. Any other measures that I should be thinking of? Any advice or pointers to information would be greatly appreciated.

Best regards,
Jim


#2

Different batteries expand different amount, depends on their surface area vs volume among the other things. You can usually get this data from the battery supplier for the specific battery. Numbers like 10% of thickness can often be seen.

Oh, and it is not “in rare circumstances” it is “always”.


#3

I’ve seen the same. 10% is a typical number, but you’ll have to get that specific number from the manufacturer.

Also agreed, it is “always”. It might be minimal, but it happens, and needs to be accounted for.


#4

Thanks for the info guys! I’ll make sure to request the specifics to my manufacturer.


#5

If I remember correctly, wasn’t the issue with the Samsung Note 7 is that it didn’t have enough space for battery expansion?

I haven’t looked into battery information much, but that’s cool to know that it lists expansion information.


#6

That was the first recall. Then they changed the supplier and had issues of electrode welding spots puncturing through the separator and thus short circuiting the battery. Well… and some other less critical issues were discovered. https://news.samsung.com/us/Samsung-Electronics-Announces-Cause-of-Galaxy-Note7-Incidents-in-Press-Conference


#7

Oooh, I didn’t know that there were two sets of recalls. Makes sense though.

Thanks for the info!