How do I remove the contacts from a coin cell? - Page 1
Forum section: electronics / beginners

author: Legion
author_rank: Frequent Contributor
timestamp: January 24, 2015, 06:37:11 pm
content: I'm not sure how these contacts are fixed to the coin cell. I want to replace the battery but reuse the contacts since I don't have replacements. They don't want to come off and I'm concerned about the metal fatiguing if I keep fiddling with it.How do I remove them from the battery?Image attached.

author: SeanB
author_rank: Super Contributor
timestamp: January 24, 2015, 06:49:38 pm
content: They are spot welded to the cell. You will either have to buy cells with tabs already welded to the cell or a cell with solder in pins already welded to it, or use a coin cell holder, or go find a local battery repacker and ask them to weld some tabs onto a new cell for you.

author: Legion
author_rank: Frequent Contributor
timestamp: January 24, 2015, 07:03:47 pm
content: That's unfortunate. I guess they really never intended for anyone to replace the battery.

author: firewalker
author_rank: Super Contributor
timestamp: January 24, 2015, 07:09:58 pm
content: Drill the spot welds with a thin drill.Alexander.

author: Zero999
author_rank: Super Contributor
timestamp: January 24, 2015, 07:22:21 pm
content: Yes you may be able to remove them with a small drill but how do you plan to attach them to the new battery? You need to spot weld them. Soldering is no an option because it will cause the battery to explode.

author: SeanB
author_rank: Super Contributor
timestamp: January 24, 2015, 08:21:45 pm
content: Find an old board with a soldered in lithium cell and unsolder that, then use it.

author: PA0PBZ
author_rank: Super Contributor
timestamp: January 24, 2015, 08:28:08 pm
content: Get something like this:or this:and be a bit creative.

author: SeanB
author_rank: Super Contributor
timestamp: January 24, 2015, 08:35:26 pm
content: For some quick work just use a small brass pad on top and bottom with the wires soldered to them, and held to the cell with a short piece of heat shrink tube.

author: Legion
author_rank: Frequent Contributor
timestamp: January 25, 2015, 02:11:56 am
content: PA0PBZ: Holders won't fit. It's from a Tennokoe Bank and it only has room for the cell. I found some coin cells on digikey that have spot welded contacts which I could make work.

author: Electric flower
author_rank: Regular Contributor
timestamp: January 25, 2015, 09:33:36 pm
content: Are those contacts necessary?If not, i'd recommend using something like this, it's conductive tape that has conductive adhesive, solder bit of wire on tape and then connect tape to battery so you don't overheat battery by soldering directly to it. Then connect or solder wires to the board or whatever. I would also use some electrical tape to tape up the battery to something so it doesn't flap around (hot glue also might do the trick)http://www.ebay.com/bhp/conductive-copper-tape

author: miguelvp
author_rank: Super Contributor
timestamp: January 26, 2015, 02:17:08 am
content: Are those CR-2320?Why don't you just buy them with tabs? (first two google results for cr-2320 with tabs)http://www.bbmbattery.com/coin-cells/3937-cr-2320-coin-cell-with-tabs.htmlhttp://www.batterybob.com/product.asp?intProdID=397040Or us a thinner battery holder and shrinkwrap it so the battery stays put.

author: CZroe
author_rank: Contributor
timestamp: September 20, 2019, 03:04:38 pm
content: This thread may be old but it still come up in relevant Google searches so I thought I'd contribute a bit of my experience with the OP's original question.I have had the battery tab spot welds sheer clean off an internal battery by putting a game cartridge in the freezer (trying to freeze sticker adhesive to make it brittle). It was Ken Griffey Junior's Major League Baseball for Super Nintendo Entertainment System, but I was unable to intentionally duplicate the originally-unintended result when I tried to deliberately do that with a couple original copies of Pokemon Red on original Game Boy (had two different tabbed batteries but we're not bootlegs). Probably a lot of factors in play here, like how fast the temperature drops, how dissimilar the temperature gets between the tabs and the cell, and how spaced apart the spot welds are (Game Boy batteries are smaller).Anyway, I never wanted to waste my cold-in-a-can on that curiosity because SNES cartridges are big enough to mount a battery holder and tabbed batteries for Game Boy games are easily available. I do wonder if a quick squirt would pop the tab right off or if getting it nice and warm before touching the spot welds to dry ice might work more consistently.For those who don't know, Tennokoe Bank is a PC Engine "HuCard," which is a credit-card sized game cartridge format for a Japanese videogame console. In order to accommodate the battery it is already thicker than a standard HuCard so there is no room for a holder and VERY little room for improvisation without just abandoning the idea of stealthily closing it back up.I like the copper tape idea but I have to wonder if there will be increased resistance. These batteries originally lasted decades (heck, many STILL work) so even a slight change could cut that life back significantly. This device is intended to backup game saves from a console that only temporarily retains them using a capacitor. Yes, a non-removable battery that can't even be recharged was the longer-term/more-permanent way to store the game save files.It's also the only way to transfer saves between consoles so it's basically an early battery-backed SRAM memory card. Too bad HuCard format didn't use PCMCIA like Neo Geo memory cards from the same era.Now that I've said all that, I'd like to point out that there are a lot of cool DIY videos and projects out there for making your own spot welder specifically for the purpose of building custom battery packs from lithium cells and nickel strips. You could use the same concept to add tabs to any CR2320 battery... or re-attach them if they can be consistently removed with cold as I suspect they might.