Can someone please run a science test on 18650?

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Jan 31, 2008
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Rhone-Alpes
Hi, Please can you test compression limit that an 18650 can withstand... Is it 20 pounds? 90 pounds?

Please can you compress some 18650's on some bathroom scales and measure on a precise caliper how many KG can change the height of the 18650? Do you have high-precision calipers at 10 microns?

I just placed 20 pounds / 10kg on a cell and the calipers measure the same... you probably have better equipment than me!!!

Cheers!!!
 
Why you do dat?
 
Because nobody knew, even vaguely, if it's 20 pounds/ 120 pounds, the previous time Wrecker Magoo asked this question in 2014!!!

Sorry I just found a science document: :) https://www.researchgate.net/public..._18650_battery_cells_under_axial_compression

The good news: They can take 600 kilograms before they explode
The bad news: They flex by 2.5 microns per kg until 10kg and 10 microns per kg at higher loads.

The 1mm gap of the positive side is completely compressed at 75 kg...

It's for weldless boxes! A strong spring is more reliable when jumping from 5ft ledges on a trail bike... So I wanted to know if 2kg springs are totally OK... I know they are, I just needed to be scientifically certain? What do you think? If you had 1/30'th of the compression it takes to completely flatten the positive side, is that too high?

Does the research document states when the elastic modulus of the steel is exceeded and the battery is permanently squashed??? Perhaps you can squash one permanently by 2.5 microns if you apply 15kg?
 
The thickness of metal in the poisitive electrode, and also the quality of the metal will vary from one manufacturer to the next.

One issue for compression-contact boxes is that the positive and negative ends might crumple slightly, long before they have a catastrophic collapse.
 
Indeed it does. The ranges of the steel can are 170-250u. The max force / the resistance kN until the battery was compressed exactly by 1000u was 70-80kg for all the cells tested, and then the short circuit happens at 500-600kg.

Even though there's lots compression contacts in the industry, There's not much information from the industry for compression forces... So the information may arise when a company has the funds to compress 100'ds of cells for thousands of hours and find out the physical properties.
 
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