Kapton Tape vs wood clamp?

[ericfx1984]

I am getting ready to build a pair of Eve 230ah 4s batteries... Curious about using kapton Tape vs a wood skid with all thread

 

[sunshine_eggo]

If your goal is to compress the cells, wood/allthread. If you just want to secure them to each other, Kapton.

 

[ericfx1984]

If your goal is to compress the cells, wood/allthread. If you just want to secure them to each other, Kapton.

do they NEED compressed?

 

[noenegdod]

do they NEED compressed?

No one really knows for certain if what is commonly being done is of any value or even a detriment.

Personally, I would never use just straight all thread and nuts. Too much risk for over compression and no resiliency. I used springs with rods and nuts and know exactly where I stand in terms of force on the cells but probably would not have bothered if I was not mobile.

Tape is by far the safest, but you may leave a little life on the table. Dont stress too much about it. Way to much is made of this topic. Do what makes the most sense for your application and forget about it. If you loose a little or gain a little, it isnt going to make or break you.

 

[Brett V]

I put a couple wraps of 1" filament tape on, followed by a layer of kapton tape. Have had no problems at all.

 

[sunshine_eggo]

do they NEED compressed?

No.

Eve lists two cycle life numbers. One for compressed and one for uncompressed. Compressed has a longer cycle life.

 

[Samsonite801]

I would compress them alone for the simple fact that it prevents them from ever bulging (which bulging can also cause stretch pressure on the bus bars and cell terminal mounting bosses later as the cells start to push apart).

And especially for mobile applications, where there is shock/vibration involved, I would only want them clamped so the cells can't wiggle around and cause more stress on the bus bar mounting bosses...

A clamp assembly also makes it easier to move around the battery if needed (when not in a box). Holds them all as one tight unit. You can still put that into a box as well of course.

 

[MadMax03]

Compress in the middle with a tie-down/ratchet strap, wrap snug with kapton above and below, remove strap, kapton in the middle.

 

[time2roll]

I used the wood skid with two zip ties.

 

[Haizhung]

Look at this setup, which is quite nicely done and probably similar to what @noenegdod mentioned when he said springs, bolts and nuts.
I like the amount of rods for equal pressure distribution. I just find it hard to find the right springs to create the recommended force of about 13-20Nm pressure.

 

[MadMax03]

I think ya'll are taking this compression thing waaaay too far, but it's really cool to see the ingenuity you guys put into it! Great stuff!

 

[codfish]

Regardless of how you secure the cells, a bit of something non-conductive between the cells is a really good idea. The thin plastic covering them will not hold up to much and I wonder if it will degrade with time like most plastics do. The aluminum cases are conductive and sometimes seem to carry a voltage. If the plastic goes, and there is contact between cells & any stray volts or moisture => aluminum case will corrode => probably something bad (electrolyte spill?)