I've been doing a lot of reading about Lithium-ion batteries and more I read the less I like them
Just last night I was trying to attach the accessory battery pack to the back of a portable DVD player.
Fortunately it was not charged. Because one of the cells ruptured when I pressed it into place.
There was nothing Sharp in the case to puncture it. It ruptured from flexure. When that happened it swelled up & the plastic case split open. The thing started getting warm and I took it outside and stuck it in a bucket.
Fortunately the state of charge was low so it never passed enough current to get hot. There were two cells in the battery case & the one which remained unruptured I purposely ruptured by poking it with an ice pick.
The reaction was immediate but not very strong because the battery was discharged. These were two pretty good sized cells inside a plastic case, each about the size of an iPhone.
Also lithium ion cells need to be especially regulated when used in pairs and multiples. You're only going to get as much performance out of a lithium ion battery pack as the weakest cell in the pack. (Not the cell with the lowest state of charge but the cell with the lowest potential capacity to accept charge) If you charge the strongest cells in the pack up to the maximum it will exacerbate this effect, in that the pack will seem dead, but if you remove the offending cell it will come back to life.
Unfortunately lithium ion cells will not all produce the same exact amount of power and it varies by as much as several percent.
Just last night I was trying to attach the accessory battery pack to the back of a portable DVD player.
Fortunately it was not charged. Because one of the cells ruptured when I pressed it into place.
There was nothing Sharp in the case to puncture it. It ruptured from flexure. When that happened it swelled up & the plastic case split open. The thing started getting warm and I took it outside and stuck it in a bucket.
Fortunately the state of charge was low so it never passed enough current to get hot. There were two cells in the battery case & the one which remained unruptured I purposely ruptured by poking it with an ice pick.
The reaction was immediate but not very strong because the battery was discharged. These were two pretty good sized cells inside a plastic case, each about the size of an iPhone.
Also lithium ion cells need to be especially regulated when used in pairs and multiples. You're only going to get as much performance out of a lithium ion battery pack as the weakest cell in the pack. (Not the cell with the lowest state of charge but the cell with the lowest potential capacity to accept charge) If you charge the strongest cells in the pack up to the maximum it will exacerbate this effect, in that the pack will seem dead, but if you remove the offending cell it will come back to life.
Unfortunately lithium ion cells will not all produce the same exact amount of power and it varies by as much as several percent.
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