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Eve 280ah prismatic grade A Cells battery build

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JJJALLOFFGRID

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My question is to compress each battery build or to not compress. All cells are New Grade A version 3 Cells. None are swollen. I've seen so many mixed views on this subject. Any advise would be much appreciated.
Thank You
Joey
 
Simpler question might be what busbars are you going to use to connect the cells and where will the battery live? The smallest footprint for a battery is to compress them. If you don't compress then the standard busbars you get with the cells will not be safe to use since you will need some insulator between the cells and then using the busbars that come with them will just barely fit. Any expansion of cells in that scenario would put stress directly on the terminals. If you don't compress you can still use the standard busbars but you'll have to rearrange the cells so that they take up a lot more space.

As far as the basic general question of compressing or not watch this video to get basics of why some people compress and why some don't and it is still okay:
 
I think the most important thing is what the manufacturer recommends in the specs for your specific cells.

You may eventually decide to approach compression in a way that optimizes some other aspect of your installation.
 
rhino said:
Simpler question might be what busbars are you going to use to connect the cells and where will the battery live? The smallest footprint for a battery is to compress them. If you don't compress then the standard busbars you get with the cells will not be safe to use since you will need some insulator between the cells and then using the busbars that come with them will just barely fit. Any expansion of cells in that scenario would put stress directly on the terminals. If you don't compress you can still use the standard busbars but you'll have to rearrange the cells so that they take up a lot more space.

As far as the basic general question of compressing or not watch this video to get basics of why some people compress and why some don't and it is still okay:
Click to expand...
Unless somebody is living in the back of a Camero.. or squeezing the battery into a battery box that has no extra space at all.. cell dividers are not going to add that much extra to the pack... if the bus bars aren’t going to accomadate a cell divider... then a decent round file should help... compress or not compress... has any pack been around long enough to truly gauge which is better..? If the pack is going into a RV or the like... then compression is probably a good idea.. Andy’s Off Grid Garage will have a very pragmatic approach to this problem..
 
JJJALLOFFGRID said:
My question is to compress each battery build or to not compress. All cells are New Grade A version 3 Cells. None are swollen. I've seen so many mixed views on this subject. Any advise would be much appreciated.
Thank You
Joey
Click to expand...
My other slant on this ... what if the cells do expand over time, or during a charge cycle.. and are under compression... where does that expansion go..? Top to bottom...?
 
Culchee said:
data relating to A123 pouch cells...
Click to expand...
Applies to EVE cells as well, they are almost the same as A123. Other Li battery chemistries also swell during cycling and if placed into large prismatic shape they need compressive force to extend cycle life. This document also references magic 12 psi number = 300kgf for LF280K dimensions.
 
From the German battery engineer where the information in Andy's video I linked to above comes from, it is only the first few cycles that benefit from compression from the initial bubbles within the electrolyte forming. After that the compression has little to no affect. The expansion and contraction after those first few cycles can not be contained because it is happening at an atomic level.

Irregardless of that it has been shown by many people that the age of the battery will degrade the battery well before you see any benefit from increased cycling lifespan from compressing the cells in a solar storage situation. How many cycles are people seeing in a solar installation? It is likely less then 100 per year. Even that A123 graph for the 12 psi shows over 10,000 cycles. That's over 100 years in a solar installation ;)
 
cells are bound to swell after sometime.. anything like keeping the cells fully charged or fully discharged for a long time will swell the cells quite quickly.. incorrect busbars cm heat the terminals affecting cell performance and contributing to cell swelling as well. so there is no real answer to this.

they recommend compressing because if not compressed and your cell swells, it will put high pressure on the terminals. You dont have to keep them very tight. You can choose to opt to keep some ventilation gap between cells but keep the busbar in a similar way, not too tight. The real problem is when your cells swell and you have compressed it tightly, and you have to open the cells, it will throw it out in a springy action, sometimes, you wont be able to unscrew the terminals... you will have a hard time disassembling the battery.
 
AntronX said:
Yes, to avoid wearing out battery terminal threads.
Click to expand...
Got a link or something?

I'm also building a battery from Eve 105's so interested in what other folks used for their build, the material these are made of, etc.

Thanks
 
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