Why Do Blister Packs With Button Cells Need Air Vents? - Page 1
Forum section: electronics / beginners

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 19, 2013, 01:07:06 pm
content: Ordered these from China and noticed blister pack has air vents (see attached picture). Why do button cell batteries need these? I didn't notice same vents on AA battery backs.

author: Rerouter
author_rank: Super Contributor
timestamp: April 19, 2013, 01:14:25 pm
content: i would assume its more for the packaging, as the difference from sea-level especially by airmail could crinkle or partly break the seal on the packaging otherwise

author: SeanB
author_rank: Super Contributor
timestamp: April 19, 2013, 04:16:00 pm
content: It is for the sealing of the cells into the packaging, as this is done with a heating pad that presses down onto a sheet of cardboard that in turn is pressed down onto the plastic blisters in a jig. No air holes means you get collapsed blisters when you remove the packaged unit from the jig as the air inside the blisters cools rapidly and the card is coated with a thermoplastic film that melts to seal to the blister PVC. Expensive for the tooling ( or you make them in wood) and the ejector pins are very expensive, and last only for around 10k of operations.

author: gibbled
author_rank: Regular Contributor
timestamp: April 19, 2013, 11:44:12 pm
content: I always thought those holes were for probing to check if the battery still holds a charge without opening the package.

author: Psi
author_rank: Super Contributor
timestamp: April 20, 2013, 12:26:05 am
content: I thought they were just a hole to use your finger and tear the cardboard away with.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: April 20, 2013, 08:09:28 am
content: Quote from: gibbled on April 19, 2013, 11:44:12 pmIs doing this possible without opening the package? How can this be done? I can only assume this can be done with multimeter.

author: orbiter
author_rank: Frequent Contributor
timestamp: April 20, 2013, 11:26:11 am
content: Quote from: gibbled on April 19, 2013, 11:44:12 pmYou'd have to have a pretty good probe to get through that hole & then round to negative side of the battery to complete the measurement

author: Fsck
author_rank: Super Contributor
timestamp: April 20, 2013, 11:29:03 am
content: Quote from: Psi on April 20, 2013, 12:26:05 amditto.

author: gibbled
author_rank: Regular Contributor
timestamp: April 23, 2013, 01:50:29 am
content: Lol about the pretty good probes, my blister packs are also perforated on the blister side. Very probe friendly...

author: Razor512
author_rank: Regular Contributor
timestamp: April 23, 2013, 02:33:28 am
content: I feel they are for probing also,. They came in handy at the store when I had to buy a replacement battery for a motherboard, and I did not want to wait for a shipment.Many stores do not sell those batteries very often and will have lots of old and to get one that was at the proper voltage I have to test about 4 different batteries. (Most were in the upper 2V but I was finally able to get one that was at 3.26V which is where cr2032 batteries are at when they are mostly fresh and not shitting on a shelf since the paleolithic age)

author: amyk
author_rank: Super Contributor
timestamp: April 23, 2013, 06:49:10 am
content: Quote from: gibbled on April 23, 2013, 01:50:29 amThose are definitely for probing.

author: G7PSK
author_rank: Super Contributor
timestamp: April 23, 2013, 09:18:54 am
content: I also thought that they were to ease the removal from the packaging, but my experience is that you still need industrial power tools to complete the removal.