I know the subject of the 300kgf ‘fixture’ (compression clamp) to extend cycle life of 280Ah LiFePO4 cells manufactured by EVE from 2500 cycles without fixture to 3500 cycles with fixture has been discussed in various threads on other subjects, but I could not find any single thread dedicated to that subject and now that I have my 280Ah cells and am beginning to think about how to assemble my battery, I am interested in current ‘best practices’ on this subject.
I have run my first charge and discharge cycle without any clamp/fixture and the cells do swell quite a bit.
So if the fixture is calibrated to 300kgf when the cells are empty, force is likely to far exceed that level once the cells are full.
And if the cells are filled before the clamp/fixture is calibrated, already-established swelling is likely to distort the battery far more than if a constant force of 300kgf had been applied during charging.
So my current thinking is to calibrate the clamp/fixture when close to empty (at least not yet bulging) and then to recalibrate every 0.1C or so as the battery charges to full.
There will still be less than 300kgf as the full battery dischargres but when bulging gets most extreme, there should be 300kgf in counter force and overall stability of cell position should be good.
Anyone else who has already faced this issues and solved these problems care to chime in?
My current plan is to use two 1/2” ABS plastic endcaps and two threaded rods per side to create the clamp/fixture.
If anyone has found a good solution to putting an entire 8S 24V 280Ah battery into a stock case with a 300kgf clamping fixture solution, I’m also interested in that..,
I have run my first charge and discharge cycle without any clamp/fixture and the cells do swell quite a bit.
So if the fixture is calibrated to 300kgf when the cells are empty, force is likely to far exceed that level once the cells are full.
And if the cells are filled before the clamp/fixture is calibrated, already-established swelling is likely to distort the battery far more than if a constant force of 300kgf had been applied during charging.
So my current thinking is to calibrate the clamp/fixture when close to empty (at least not yet bulging) and then to recalibrate every 0.1C or so as the battery charges to full.
There will still be less than 300kgf as the full battery dischargres but when bulging gets most extreme, there should be 300kgf in counter force and overall stability of cell position should be good.
Anyone else who has already faced this issues and solved these problems care to chime in?
My current plan is to use two 1/2” ABS plastic endcaps and two threaded rods per side to create the clamp/fixture.
If anyone has found a good solution to putting an entire 8S 24V 280Ah battery into a stock case with a 300kgf clamping fixture solution, I’m also interested in that..,