Battery orientation questions

[hecateh]

Hi All, I have finally started putting my battery together, comprised of the cells from an MG ZS EV 44kWh pack. I was in the process of mounting them to the wall in a sideways orientation with the base of the battery facing the wall, long side down (so internal cell short side down) and I stumbled on someone doing a similar project with a BMW i3 battery which was still inside its case. Their project had comments asking whether or not its ok to mount sideways like that and it got me thinking I have no idea if my own cells can do the same. So I came to ask if anyone can point me in the right direction before I ruin my stack of cells! I have been scouring the web all day trying to find any details on the cell limitations before I start to attach them, so any help appreciated!

Pictures of the cells attached:

 

[Korishan]

Mounting sideways isn't really the issue. The big issue is the weight applied to the bottom-most cells. The manufacturers have said it's ok to use them sideways. One thing that hasn't been tested yet is the long term affects of using cells in horizontal position under high compression on the bottom and virtually zero compression on the top cell because, well, these haven't been used like this for long periods yet. So it's still up in the air as to whether or not it is bad to use them in horizontal position over long periods of time and capacity of those cells.

I would recommend having a shelf to hold the weight at the 4 in height. Some cases are actually built with those shelf wings for this purpose, but not common yet.

Sooooo, basically at this point use them stacked like this at your own risk. Make sure to keep the cells monitored and check for cells getting more and more balancing required under normal conditions. Ie - if a cell normally gets balanced at <1Ah per cycle then starts to climb up to 5Ah per cycle there may be an issue developing. Numbers are just example, tho. Just keep an eye on outliers.

 

[hecateh]

Thanks for your prompt reply, this gives me great confidence as I wasn't going to be stacking them on each other, they would be bolted to a frame on the wall, using their mounting holes, just in a rotated position.

 

[Dala]

Depends on the battery manufacturer. Most EV packs are OK with sideways orientation. Checkout this document for the Nissan LEAF, meaning it is OK to put the battery on its side for a vertical mount, but it is not allowed to put it with the HV connectors facing up for some reason.

 

[hecateh]

Interesting, thanks for the info, I wonder where they get these rules from, I am going to imagine its from experience and someone doing something unexpected.