Main Traction Battery Upgrade i-MiEV

[MickeyS70]

Pricy? yes.

At first glance definitely, but you can easily offset that expense if you sell your old cells for solar storage and charge extra to include the original bus bars..

 

[Jiminy]

I think these press fit nuts might be a better option since we could reduce the thickness of the bus bars to 1.6mm from 3.2mm. Cost for 66 pieces of Bus B goes from $436.26 USD for 3.2mm Cu down to $231.66 for 1.6mm. I think they could be installed with a vise or arbor press, worst case. Cell height would have to be adjusted downwards by 1.5mm to accommodate the thickness of the nut. OR, maybe they can be installed in the underside of the bus bar.

 

[Jiminy]

I think Kiev is right about aluminum. The terminal blocks are aluminum so why make the bus bars copper? If we can use the pem nuts for the 3mm thread then we can get the price for 77x pieces even in 2.0mm aluminum down to a more palatable level. SCS want's $1.23 each for the press fit (pem) nuts installed. Unfortunately, their minimum part size for debur is 5 inches so we would have to knock off any interfering hard edges with a file before installing them.




Tapped 2.3mm thick aluminum:

 

[Jiminy]

Y'all will have to pardon me. I'm on a roll today.

From: https://help.leonardo-energy.org/hc...-area-of-conductor-cables-Copper-vs-aluminium

"One of the major differences between copper and aluminium is that copper has a significantly lower electrical volume resistivity than aluminium. This property quantifies how strongly a given material opposes the flow of electric current. A low value indicates a material that readily allows the movement of electric charge. On a relative scale the differences are significant: copper has a volume resistivity of 1.72e-6 Ohm-cm, compared to 2.82e-6 Ohm-cm for aluminium.

This difference is particularly relevant when designing and installing electrical networks and related components. To attribute to an aluminium conductor the same resistance as a copper conductor, the cross-sectional area of the aluminium conductor must become larger to compensate for aluminium’s higher electrical resistivity. In fact, the aluminum conductor will have a cross-sectional area 64% larger than copper for the same current-carrying capability. This leads to a number of serious drawbacks."

I think we would need to use 3.2mm thick aluminum and make it 20mm wide to replace the 18mm wide 2.0mm copper bus bar. That is roughly 64% 78% greater cross sectional area if my rusty math is correct. 36 millimeters squared vs 64. There is no material between 2.5mm and 3.2mm and 2.5mm is too thin. I hope someone checks that for me.

Jim