Ever wonder how the Big Boys build a battery pack? I know I’ve struggled with getting stuff mounted securely, managing lots of tiny and not-so-tiny wires, handling huge current all while trying to make it look like something that should actually be on a motorcycle. It’s no wonder you tend to see this all concealed inside a box. Here’s the stuffing of a ca 2010 Zero X battery pack, which, as far as I know, was the same from 2008-2011.
These are what’s referred to as the “Molicel” packs, running the Molicel IMR-26700 cylindrical cells, sporting a manganese dioxide positive electrode material and a graphitic carbon negative electrode – LiMn2O4. This is giving you 3.8V and 2900mAh. The data sheet for the cells is here: IMR26700
The packs are set up in a 14s 12p configuration, which gives you about 58V at 35 Ah, or about 2kWh.
So here’s the breakdown. The stacks you see from the side are banks of 12 paralleled cells.
There are 14 stacks total. One side of the series connection is butt-to-butt inside these cardboard tubes:
The other side is along the outside bus bar strips shown here:
You’re also seeing the spade connectors for the BMS wires. On the “bottom”, you just have the bus bars.
On the way to the (relatively small) Anderson connector you get the pack fuse.
You’re also seeing some nice wrapping on those cables.
I need to track down these multi-pin connectors for the BMS harness:
They look like computer hardware to me.
So yeah. The two cells are simply butted against themselves in the tubes. I’m told it’s simply a pressure-clamp affair holding the bus bars you see coming out of the top to the pairs of cells. Held in place by a continuous elastomer retaining device. Yes. That’s right. A rubber band. Shrink-wrap those puppies together, squirt a little hot glue on them, and you’re in business. That closed-cell foam you see is just a strip hot-glued to the top of the pack.
I’m feeling a lot better about what I thought was kind of a mickey-mouse construction of my Turnigy pack. Hell, my CALB pack looks downright perfesshional.