Page 1 of 3

Modular Rebuildable Repairable 18650 battery.

Posted: Feb 10, 2016 7:53 pm
by shawname
Thought I'd introduce a way of assembling 18650 cells into a battery that does not commit the cells by spot welding. The battery can be disassembled to be repaired, to have the cells upgraded, or reconfigured to change voltage or ampacity.

"BatteryBlocs®" are built from parallel groups of 4, 6, 8 and 10 cells. The cells are held together with "magnetic compression." The Blocs are stacked to multiply voltage and/or amperage. They are designed to fit into 4 inch plastic fencepost sheaths, but can also be assembled into a powerwall or even a radial design. I think they look real cool, and I love showing off my batteries.

I saw the need for a battery I could control after disappointments with Chinese made batteries. I worked for a couple of years designing and testing the concept, and when I thought I couldn't improve it anymore I tested it by riding my Mundo around the USA on a door to door 4 month 9,750 mile journey. Upon returning, I took the lessons learned and refined the battery case design into what it is today, there is a patent pending. The book is on Amazon, "Loop the USA, an ebike Odyssey", by Shawn McCarty.

I'm just starting to market the cases and would appreciate feedback. http://www.batteryblocs.com

Image

[moderator edit to fix link, and add pic]

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 10, 2016 10:59 pm
by Hillhater
Any testing done on the resistance of the magnets compared to spot welded connections ?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 9:17 am
by Scottydog
Personally I'm quite impressed! I think the concept of small mini modules makes it easier to maintain good pressure on the connections with the tensioning bolts. Obviously the bolts needed to be plastic, but is the idea that they create a degree of elasticity and keep even pressure? The modular system is great!

I've often thought about 18650 packs, but purchasing complete welded ones for massive capacities seemed daunting.

Personally I think plated copper plates would be more appealing, the steel ones less so, though I guess a degree of stiffness is important? Aluminium perhaps? Would a conductive paste also be good?

I liked the video explanations, only watched one.

Didn't check you page, but to have the full dimensions for each size along with assembled weights would be good also!

awesome job!

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 9:19 am
by Scottydog
Just saw the calculator on the website! Awesome going to download! :D

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 9:26 am
by Scottydog
I see the ones on the site look 3D printed, are the production ones to be molded of some sort?

Also the addition of pack size and weight would be good. That addition to the spreadsheets could be good.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 11:25 am
by shawname
Hillhater wrote:Any testing done on the resistance of the magnets compared to spot welded connections ?
15 magnets stack to about 1" with no measurable resistance on my ohm meter. They are nickel plated neodymium.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 11:36 am
by shawname
Scottydog wrote:Personally I'm quite impressed! I think the concept of small mini modules makes it easier to maintain good pressure on the connections with the tensioning bolts. Obviously the bolts needed to be plastic, but is the idea that they create a degree of elasticity and keep even pressure? The modular system is great!

I've often thought about 18650 packs, but purchasing complete welded ones for massive capacities seemed daunting.

The battery I looped the USA with was a 68 amp hour 50.4 (14S) battery. That's 3.4 KW. Working on a 100 volt 44 amp one for a customer- with a 125 amp draw!


Personally I think plated copper plates would be more appealing, the steel ones less so, though I guess a degree of stiffness is important? Aluminium perhaps? Would a conductive paste also be good?

Sure gave this some thought, and did the math, but the galvanized steel is magnetic, and not much less conductive than nickel. Used in .032 thickness it has very little resistance. The connectors can always be doubled for even less resistance.


I liked the video explanations, only watched one.

Didn't check you page, but to have the full dimensions for each size along with assembled weights would be good also!

Hmmm, yes, they are in the products page. At least the dimensions. I should put the weight as well, thanks.

awesome job!
Thanks!

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 11:49 am
by shawname
Yes, the plastic parts of the cases are 3d printed from PLA. They are complex and 3d printing is very cost effective. Injection molding would give a better finish, but I can't justify the cost of the molds.

The plastic parts hold up quite well when not exposed to the elements. If left in the sun or exposed on an ebike, they can be brushed with Spar Varnish, which gives a nice shiny protective shell and provides UV protection.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 12:45 pm
by Grizzl-E
Hey if you haven't tried it yet pick up some petg filament. It prints almost as easy as pla but is stronger than abs. It's become my new go to filament for anything production.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 1:57 pm
by bowlofsalad
shawname wrote:
Hillhater wrote:Any testing done on the resistance of the magnets compared to spot welded connections ?

The magnets are nickel plated neodymium. A 1" stack - 15 magnets- shows no measurable resistance on my Klein ohmmeter.
Are you using galvanized steel for these kits?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 2:41 pm
by shawname
Yes, I am using galvanized 1010 steel. The steel is 12% as conductive as copper. The zinc coating is 27% as conductive as copper.

Compared to spot welding? You need resistance to weld. Solid nickel strips are 22% as conductive as copper. And the battery builder may have used nickel plated steel- it's the most common connector. And the strips are small compared to BatteryBlocs connectors.

The larger the connector the less resistance. And the larger the connection area the less resistance. That's why BatteryBlocs' connectors are massive and the tops are open to allow massive contact area.

I'm not saying one way is better than another, I do both in my shop depending on the job. I spot weld when I have to fit the cells into a small preexisting case. But when I am just building a battery, I go for the modularity and solidness of BatteryBlocs.

Staying with the same material also prevents galvanic action- it plagued me on some of the earlier aluminum/stainless designs!

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 2:56 pm
by Scottydog
I watched the videos, see magnets are used also, that makes the need for the steel correct? Neat design, the fence post packaging is a good one! :D

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 11, 2016 5:56 pm
by shawname
Cool, thanks for taking the time.

Yes, the fence posts work great. They are a good size, 4" fits between the knees!

I'll do another video soon on the endcaps- with cell loggers and xt60 and xt90 connectors and sensor wire connections.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 19, 2016 9:45 am
by shawname
I've been working with the PTEG filament on your suggestion, thank you. It does print well. It bridges less well than PLA, and there is a big bridge on the BatteryBloc case. Also, it is less rigid than PLA..... I can see where this would be desirable in some cases, but I like the structural integrity of PLA for BatteryBlocs.

Thanks for the suggestion though.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Feb 26, 2016 10:14 pm
by Grizzl-E
No worries. Glad to see you making this idea work and available. I have been trying a similar base concept with milled pcb boards on either side of a printed spacer pack. Partially to make it rebuildable and partially to make it easier to travel with an ebike battery. Pop off the sides and you have a large number of 12~ wh batteries that don't have any carry on restrictions. I have had trouble using a punch to raise the connectors though without destroying the pcb board it the process

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 5:06 am
by spinningmagnets
I am really impressed by these...paradigm shift?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 10:38 am
by tiny_n_terrible
A similar concept was tried years ago by a motorized bicyclist named Safe.
He used parallel tubes of batteries to achieve the desired voltage and amperage output.
Vibration and inertia from road hazards and bumps caused random open circuits through out the battery pack.
He could not get his battery pack to work reliably.
Maybe you can ?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:10 pm
by shawname
Thank you for your comment.

My pack is reliable. The neodymium magnets provide button tops for the cells and make it easy to assemble. It's the nylon bolts that provide the compressive strength. A feature of BatteryBlocs is that it can flex and vibrate and not have any spot welds break!

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:35 pm
by JumperJackFlash
Really clever idea.

How much strain can the bolts take?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:44 pm
by ejonesss
the cells that you sell you say sold with kit purchase.

if i buy a 10 pack kit then am i able to buy 10 cells? or how does that sold with purchase work?

i like your product it looks very good but i will wait until i see if it stays around because i have seen many products come and go and even get taken over by other companies who then sell them from china.

i am glad to see that you are in the united states especially when buying cells because of the hazmat with batteries.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:51 pm
by shawname
Yes, I stock Panasonic 18650B cells at 3350 mah hours. I build battery packs both spot welded and with BatteryBlocs and so always stock those cells. I sell the cells at a bit over cost as an incentive to purchase BatteryBlocs. You can buy the number of cells it takes to fill your BatteryBlocs order, but I can't afford to sell the cells without a BatteryBlocs order. I order the cells in 1000 cell lots from my supplier in Hong Kong.

Hope this explains it!

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:52 pm
by shawname
JumperJackFlash wrote:Really clever idea.

How much strain can the bolts take?

Hmm, they are nylon bolts rated for 16 foot lbs torque. A 10 pack has four of them. When tightened they clamp the cells tightly, but not so tightly the cells can't be rotated with resistance.

Does this help?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:58 pm
by ejonesss
shawname wrote:Yes, I stock Panasonic 18650B cells at 3350 mah hours. I build battery packs both spot welded and with BatteryBlocs and so always stock those cells. I sell the cells at a bit over cost as an incentive to purchase BatteryBlocs. You can buy the number of cells it takes to fill your BatteryBlocs order, but I can't afford to sell the cells without a BatteryBlocs order. I order the cells in 1000 cell lots from my supplier in Hong Kong.

Hope this explains it!

do you mean under cost? because if you sell over cost then you can afford so the only i can think of to not be able to afford is to sell under cost

still it is a very good deal at $4 a piece where as other places sell them at $8 a piece.

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 27, 2016 12:59 pm
by JumperJackFlash
Have the nylon bolts ever snapped during rough riding?

Re: Modular Rebuildable Repairable 18650 battery.

Posted: Aug 28, 2016 4:46 pm
by ejonesss
Scottydog wrote:Personally I'm quite impressed! I think the concept of small mini modules makes it easier to maintain good pressure on the connections with the tensioning bolts. Obviously the bolts needed to be plastic, but is the idea that they create a degree of elasticity and keep even pressure? The modular system is great!

I've often thought about 18650 packs, but purchasing complete welded ones for massive capacities seemed daunting.

Personally I think plated copper plates would be more appealing, the steel ones less so, though I guess a degree of stiffness is important? Aluminium perhaps? Would a conductive paste also be good?

I liked the video explanations, only watched one.

Didn't check you page, but to have the full dimensions for each size along with assembled weights would be good also!

awesome job!


magnets do not stick to Aluminium or copper anyone who works with scrap metals knows this it is the easiest to tell if a piece of metal is tin or steel or not.