Im dissasembling 18650 power pack. help their are sparks and smoke - Page 1
Forum section: electronics / beginners

author: lmancinicrawford
author_rank: Newbie
timestamp: January 23, 2024, 09:03:17 pm
content: im disassembling a power pack right and im using plyers to rip the spot welds off. In the process, there were sparks and at one point a smoke patch appeared. Im scared its going to blow up. Ive attached and image of my progress. Is there any safe way to remove the welds? I've also snipped the BMS. Ive added an image of the plyers i was using. i was doing a twisting motion

author: audiotubes
author_rank: Regular Contributor
timestamp: January 23, 2024, 09:14:21 pm
content: Call the Fire Department

author: Gyro
author_rank: Super Contributor
timestamp: January 23, 2024, 09:27:33 pm
content: Scarily this is nothing new on the forum...https://www.eevblog.com/forum/beginners/how-to-prevent-sparks-while-salvaging-18650-cells-from-old-battery-packs

author: lmancinicrawford
author_rank: Newbie
timestamp: January 23, 2024, 09:28:58 pm
content: ive already looked through that feed. i just dont understand where he cut to not short the battery hence yy i have made my own post

author: shapirus
author_rank: Super Contributor
timestamp: January 23, 2024, 09:32:44 pm
content: In a nutshell, you want to cut the connecting strips, not the cells. Don't try to tear them off, as it can damage the cells. Be extra careful around the positive terminals, as operating near them means a greater risk of creating a short circuit.Lastly, don't do this at home. Or if you do, have a fire-proof enclosure handy.

author: amyk
author_rank: Super Contributor
timestamp: January 24, 2024, 01:05:51 am
content: Quote from: shapirus on January 23, 2024, 09:32:44 pmThis. Keep in mind that the cans of the cells are negative. Cut the strips connecting them together, one at a time, and then you can peel them off the cells carefully.

author: sleemanj
author_rank: Super Contributor
timestamp: January 24, 2024, 01:58:06 am
content: I would break them down into five 2S3P modulesFirst remove all the outer shell and wires so you can get to the cells.The long strip of 6 along the side I marked 1 will then easily bend out and give you plenty of room to cut the strips on the other side attaching that block to the other cells.Then blocks 2 and 3 should also fold out and cut off, and then 2 and 3 can be folded apart and cutFinally 4 and (what's left of) 5 can be separated.Once you have those 5 blocks isolated, if you need them further isolated then you can proceed in the same manner, just folding the blocks open like a book and cutting the links between cells.

author: Infraviolet
author_rank: Super Contributor
timestamp: January 24, 2024, 05:19:55 pm
content: What is it you want the cells for? If you've salvaged the pack from somewhere it is always possible the cells might be in a pretty rotten condition and not much use even when separated out. Also, not only should you make sure to do all this disassembly outside and on a surface that can't catch fire (concrete, not dry grass...), but also if you sucessfully salvage any cells then any future charging of them probably ought to be done outside too.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 24, 2024, 06:49:31 pm
content: cover the other nodes with tapes or something insulating while trying to brute force dismantle a node at a time all you like. with a little bit time spent to gain common sense and look around, you can understand how it works and where the short can be caused. they all just some parallel + series configuration nothing rocket science.

author: MarkT
author_rank: Frequent Contributor
timestamp: January 25, 2024, 12:48:12 am
content: Those long nosed pliers are obviously at risk of shorting to other strips than the one you are cutting - this is a job for side-cutters.

author: inse
author_rank: Super Contributor
timestamp: January 25, 2024, 08:09:23 am
content: I also dismantled a simular battery pack and used a dremel-type tool with a cutting wheel to separate the blocks.Mine had the cells arranged in a plastic grid, so I had to cut EVERY tab to remove them.It is safer to remove the tabs from single cells or even keep them to solder new packs in case you don’t want to or can’t spot weld new ones.

author: CaptDon
author_rank: Super Contributor
timestamp: January 25, 2024, 02:26:57 pm
content: 6 cells in parallel....WOW... and in close proximity!!! There's a fireball in the making!!! That thing would look spectacular in a total thermal runaway!!! Kind of like those Tesla battery storage units the size of a shipping container. They tend to burn for about 24 hours straight.

author: Mechatrommer
author_rank: Super Contributor
timestamp: January 26, 2024, 03:00:20 am
content: from the look of it... 3 parallel cells of 8.4V per pack, and there are 5 packs, not sure whats underneath whether series or parallel connection. if series, it is 42V pack altogether somewhere 3-9Ah.