Show me your "18650 on a PCB" solutions - Page 1
Forum section: electronics / projects

author: dusan
author_rank: Regular Contributor
timestamp: June 09, 2024, 12:10:34 pm
content: I just found out that if I get rid of the battery holder and mount battery directly on PCB I can fit my project into 30% smaller box. I'm looking for an inspiration how to mount 18650 directly on PCB. Please post even if you think your solution is inferior to others, it may work better for me as every project is different. Thanks.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 09, 2024, 01:07:57 pm
content: The most common solution is to spot weld tabs to your batteries. You can even buy batteries that already have these tabs and can be soldered directly into the PCB.Some people claim to have success with soldering wires directly to the battery by using a hot iron, keeping the heating time to an absolute minimum, and cool with water (wet cloth) directly after soldering. But I'm not sure what that does to battery internals and it's probably a bad idea.You can also buy batteries (or battery packs) with wires and a plug on them.For the rest, I'm quite happy you can buy decent battery holders for 18650. For AA for example the battery holders are usually so bad that they become very unreliable.

author: Psi
author_rank: Super Contributor
timestamp: June 09, 2024, 01:10:42 pm
content: You can get sort of "curved L" shape SMT spring metal battery contacts.What about a battery sized internal routed cutout in the PCB for the battery to sink into.Then the top and bottom battery contracts are SMT.Since the battery is sitting in the middle of the PCB they will align to the center of the battery.Then you only need something to restrain the battery, which could be a velcro strap that threads through two long slots in the PCB either side of the bigger cutout where the battery sits.

author: ArdWar
author_rank: Frequent Contributor
timestamp: June 09, 2024, 01:32:27 pm
content: Quote from: Doctorandus_P on June 09, 2024, 01:07:57 pmDon't do that please.Either do a proper spot welding, or use one ofthose naked terminalinstead. Less plastic while still replaceable.Beware of its tendency to damage battery insulator sleeve and potentially causing short circuit however.

author: voltsandjolts
author_rank: Unknown
timestamp: June 09, 2024, 01:44:54 pm
content: I recently purchased a FNIRSI SWM-10 battery tab spot welder, £45 delivered to UK from FNIRSI store on aliexpress.https://www.aliexpress.com/store/2939001It's near it's limits doing 0.1 nickel tab to 18650, but does a good job of it. Might be OK for 0.15 at max settings.If saving space is critical for you, then tab welding is the only way to get shorter than a spring clip type fitment.

author: RoGeorge
author_rank: Super Contributor
timestamp: June 09, 2024, 01:51:10 pm
content: Quote from: dusan on June 09, 2024, 12:10:34 pmDepends what do you mean by 30% smaller.18650 is one of the most common type, but that is only one of the standardized sizes for cylindrical Li-Ion batteries (18x650 mm is diameter x length). If that is too big, maybe choose a smaller cylindrical battery, or maybe a flat format one.

author: voltsandjolts
author_rank: Unknown
timestamp: June 09, 2024, 01:56:32 pm
content: Quote from: RoGeorge on June 09, 2024, 01:51:10 pmHmm, yeh, I think 650mm long would be too big18mm x 65mm, format 0, which means cylindrical.

author: DimitriP
author_rank: Super Contributor
timestamp: June 09, 2024, 09:24:49 pm
content: How about this clip from digikey ?DigiKey Part Number 36-54-NDManufacturer Keystone ElectronicsManufacturer Product Number 54Description BATT CONT CLIP 18650 1CEL PC PINhttps://mm.digikey.com/Volume0/opasdata/d220001/medias/images/1124/MFG_54.jpg

author: tszaboo
author_rank: Super Contributor
timestamp: June 09, 2024, 10:04:31 pm
content: I buy it as a 1S1P pack, with protection circuit and NTC, with JST 2.5mm connector. Cable tie to PCB.Not for my ATEX stuff obviously.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: June 10, 2024, 01:48:55 am
content: Quote from: voltsandjolts on June 09, 2024, 01:56:32 pmEuhm, no.Length is in 100um instead of whole mm.CR2032 is for example 3.2mm thick.https://en.wikipedia.org/wiki/Button_cell#Package_size

author: voltsandjolts
author_rank: Unknown
timestamp: June 10, 2024, 09:32:33 am
content: Quote from: Doctorandus_P on June 10, 2024, 01:48:55 amIEC standard 60086-1 describes the naming convention for cylindricalprimarycells, which works as you described.IEC standard 61960-3 describes the naming convention for lithium secondary cells, but the 18650 designation precedes this and doesn't conform.There is conflicting information out there for 18650, a term which was coined back in the early 1990's. Some say 0=cylindrical, some say 0=65.0mm. I don't see a definitive explanation from Sony or Panasonic, one of whom likely instigated it.Quote

author: voltsandjolts
author_rank: Unknown
timestamp: June 10, 2024, 09:35:04 am
content: OP: there is also 17500 lithium ion cells, shorter with reduced capacity of course.