BMS on every cell

[robbiemont]

New member feeling a bit desperate, I recently bought second hand battery pack's I think they are out of a Bolt EV. the config is 2p3s x2 I want to use an active BMS how ever to connect every cell individually I will have to cut or grind the spotwelds to separate the 2 parallel config is this necessary?
Not having abms on individual cells I believe may have been part of the problem with the pack's.

 

[JackFlorey]

I want to use an active BMS how ever to connect every cell individually I will have to cut or grind the spotwelds to separate the 2 parallel config is this necessary?
Not having abms on individual cells I believe may have been part of the problem with the pack's.

In general, no. In a Tesla Model 3, for example. they use a 46P96S battery, and all 46 cells are connected together and protected by a single channel of the BMS.

 

[fechter]

Right. When cells are connected in parallel, their voltages are forced to be equal and therefore can be monitored by a single channel on the BMS. Each series group needs a separate BMS channel.

 

[lnanek]

One thing I have seen done per cell is buying nickel strips with a narrow portion that acts as a fuse where it connects to each cell. So although it doesn't make sense to wire individual cells of a p-group to the BMS vs. just the p-groups, some people do put a fuse on each individual cell.

 

[robbiemont]

Thanks, I'm looking for a BMS any recommendations? Been looking at
Daly LiFePO4 16S 48V 100A

 

[robbiemont]

That's 48 cells in total.