[xevion]

Does anyone know if Gen 3 Nissan leaf battery modules have internal cell fuses? I'm going to wire my modules up to my BMS today, and I was told having cell fuses is best practice. I know on some battery modules there are internal cell fuses but can't find any info about the Gen 3 Nissan modules. Mine are the 7S3P modules from a 2019 Leaf.

As a follow up question, if the cells are not fused internally what type of fuses should I use, or should I use cell fuses at all? Thanks!

 

[brian_]

No one uses fuses for the power connections to individual cells except with cylindrical cells... so no, there shouldn't be any in any Leaf battery module, and none need to be added.

I don't know if there are fuses on the BMS tap connections, but I doubt it.

 

[Eli81]

Cell-level fusing for power is only best practice/necessary when you have large numbers of cells in parallel, like with Tesla modules. With lots of parallel cells, the current through each one is low, allowing you to use a fuse value that will blow if something goes awry.

Since the Leaf modules are only 3P, you would need like 200A fuses on each cell - impractical and unnecessary.

If you mean for the voltage sense connections, there are none there either - the wires are welded directly to the cell bus bars. Some EV modules do have voltage sense level fusing, like Kia Soul EV modules, but most manufacturers don't bother - the thin voltage sense wires themselves are basically fuses.

Of course, it wouldn't hurt anything to add your own, and would help protect against fire if the harness were to get smashed.