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Mounting Odd Sized Battery to PCB?

Hello all, I am working on a project with a group, and i am trying to design a power board for it. I am trying to find a method of mounting the batteries so that they will be easily replaceable. I am using 2 lithium ion batteries, with surface mount connections, with dimensions of 5.8*54*60mm. I was thinking about having a small sister board ,a little bit bigger than the batteries, that I could sandwich the batteries around, and put my thermistor in between the board and a battery. Then I would connect the sister board to my main board that has my charger on it through a header or connector.

My problem with that design is that I need to find a way to mount the batteries to the pcb while still making them easily removable. I was not able to find any mounting clips for that size of battery on digikey, or various other places online. I was contemplating having holes drilled into the pcb and using zip ties to hold the batteries down, while this is tacky, it also poses a problem if the batteries fail because they tend to inflate when they fail. I also wanted to try and avoid gluing the batteries if at all possible.

I was also thinking about using the sister board as a large ground plane...

I also need a method of attaching the sister board to the larger power board, I was contemplating using two headers on each end of the sister board to form a mount, I'm not sure how secure that would be, I was also contemplating drilling holes and using metal spacers and screws to hold the boards together.

I would appreciate any help you could give me on this project, I don't have any real experience with building pcb's, only designing circuits on paper, so I would appreciate any warnings of pitfalls you think I might run into with this setup.

The entire project is going to be put inside a 10cm^3 container, so space is at a premium, and later versions of the board will be weight sensitive, and of course this is a time and money sensitive project.....but aren't they all?

Anyways, I would greatly appreciate any advice, ideas, etc. you could give me on this project. Thanks.

*ps, could somone repost this so people who block gmail accounts might be able to help me out as well? thanks*
Reply to
UAFEEUndergrad
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Waltz into your local hobby shop and buy a 2-cell LiIon pack designed for model airplane use. Then put whatever power connector you want onto it, and go.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" was written for you.
See details at http://www.wescottdesign.com/actfes/actfes.html
Reply to
Tim Wescott

We don't do homework for others here. At the very least you should provide us details on the battery type, part number and manufacturer, a web link would suffice. Have you looked into Keystone? Or how about velcro and pogo pins? Use thin strips of PC board material to make a nest for the batteries to rest in, solder them perpendicular to the main board Regards, al

Reply to
mickgeyver

I lift far fewer pads with SMT devices than I did with PTH. Pins in planes can be a PITA. OTOH, RoHS sucks the big one.

Reply to
krw

PTH and internal planes are the worst. Without preheat, it's nigh on impossible to recap a faulty motherboard (what, ~8 layers?), even with a nice and toasty soldering iron.

PTH tends to be frozen on the top, so the pad (or PTH itself) tears out. When desoldering, I like to heat it from the component side when possible!

SMT on the other hand, stick the whole board under a torch, heat it up slowly (a few minutes...ha), then scrape or knock off your bonanza of assorted parts. ;)

Tim

--
Deep Friar: a very philosophical monk.
Website: http://webpages.charter.net/dawill/tmoranwms
Reply to
Tim Williams

Surface mount connections rule OUT the "easily replaceable" part, as a bit of ham-handed unsoldering can destroy the pads.

Reply to
Robert Baer

Best way with PTH is to clip all the leads off and remove them one at a time. Then clean out the holes with a vacuum desolder tool. RoHS really does suck.

tm

Reply to
tm

Do you know what a standard roll of solder of the Sn96.5 AG03 Cu.5 variety goes for? The mil spec stuff is even more.

Reply to
MrTallyman

Only an idiot would reflow an entire board of hundreds or thousands of solder connections to service only a few. Then again, you did also say "torch".

The sad thing is that I know you to be smarter than that in other segments of the industry.

Yes, preheat is a must for servicing multi-layer through hole.

Reply to
TheGlimmerMan

"TheGlimmerMan" wrote in message news: snipped-for-privacy@4ax.com...

Poetic licence.... Tim's quite correct in his approach. We bake boards at 60 deg. for 4 hours before touching them. For BGAs it's 48 Hrs at 100 deg.

Reply to
TTman

UAFEEUndergrad schrieb:

Hello,

there are enough exchangeable lithium cells for which battery holders exist. Just select a combination of cell and holder available at digikey.

Bye

Reply to
Uwe Hercksen

MrTallyman wrote in news: snipped-for-privacy@4ax.com:

what happens if you use 63/37 Sn/Pb for the repair? does the RoHS police kick down your door? lose your license?

--
Jim Yanik
jyanik
at
localnet
dot com
Reply to
Jim Yanik

What would dimmie know about that?

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.
Reply to
Michael A. Terrell

Sometimes, with PTH - and frustration - a chainsaw comes to mind. :-(

Ed

Reply to
ehsjr

Cutting torch. ;-)

--
Politicians should only get paid if the budget is balanced, and there is
enough left over to pay them.
Reply to
Michael A. Terrell

The ROHS Police is a figment of everyone's imagination...I know of at least two small companies that don't even know what lead free solder looks like....4 years down the road. Good luck to them... :)

Reply to
TTman

IOW, it's like cutting corners and bending the rules/laws anywhere- if you're small, low profile about it, and don't visibly hurt anyone too much, you can get away with it for quite a while.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
Reply to
Spehro Pefhany

Tim is also talking about reclaiming the parts, not the boards. Of course DimBulb is too dim to read.

Reply to
krw

Who gives a crap, DimBulb?

Reply to
krw

Yes. Your board is no longer RoHS if you as much as touch an iron that has touched Pb to the board.

Reply to
krw

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