Making a custom battery pack for MiEV

[MickeyS70]

Haha, we customized studs and provide busbars ,spacer also available ：）

Doesn't look like these cells will fit across the CMU boards I'm afraid...

LEV50: 171mm x 44mm x 98mm
CATL93: 172mm x 42mm x 90mm
SVOLT90: 148 mm x 39mm x 102mm (short and high)

[edit] actually the CMUs are only 65mm wide, but the excess height is going to be a (mission impossible??) challenge..

 

[stoatwblr]

It's worth noting that both the CATL and SVOLT cells are limited to 1C charge/3C discharge whilst the original LEV50s are 2.5C charge/6C discharge

That puts the allowable currents at _about_ the same for discharge, but charging will need to be limited a little (not that I've ever seen Chademo exceed 65A even with 150kW chargers, so the existing programmed limits may be fine)

One of the things that I've been wondering about would be shoehorning LiFePO4 cells into the packs. I know that would require serious reprogramming and potentially mean a 20% reduction in peak power, however they tend to have vastly greater tolerance of charge/discharge currents as long as the low-end thermal requirements are met (ie: no charging below freezing and a pack heater probably needed) and they have longer cycle lifetimes than NMC

There's a bigger problem eyeing most of us in cold(ish) climates where road salt is used: Chassis corrosion. These are repurposed JDM cars and have fairly poor rust protection. It may not be worthwhile investing several thousand dollars in a new battery pack if the car ends up failing annual safety inspections due to rotted-out suspension mounts

What are people finding under the skirts when the battery pack is dropped out?

 

[jray3]

What are people finding under the skirts when the battery pack is dropped out?

My cars here in Western Washington are pretty rust-free, but the car that spent a few winters on salty roads in Colorado was much worse, with several of the splash tray retainer bolts snapping off when I dropped the pack.

 

[Jiminy]

Except CATL93,what other batteries are suitable for Mitsubishi imiev & outlander?
We have solution without changing the original bracket!

Your task is simple: Make an exact copy of the LEV50/LEV50N battery cell in every dimension but with newer chemistry. This includes perfectly copying the terminal base plates and 8mm terminal studs. Make it a direct swap for the stock Yuasa cells with no other parts needed. Use a chemistry with little or no silicone so swelling will be reduced at EOL. Sell IR matched sets of 93 cells (5 spares). Confirm quality with high grade equipment to measure IR and include a report with every set. Crate them up and you will get orders. $3500 per set plus sea freight.

I'm so surprised that this hasn't already been done. Seems like there are tons of generic "Catl 94Ah" cells of various dimensions close to but not including 171/44/98. Make an exact copy and you will be off to the races! I have OE Yuasa cells to send you if you need a template.

 

[AlcidesR]

Your task is simple: Make an exact copy of the LEV50/LEV50N battery cell in every dimension but with newer chemistry. This includes perfectly copying the terminal base plates and 8mm terminal studs. Make it a direct swap for the stock Yuasa cells with no other parts needed. Use a chemistry with little or no silicone so swelling will be reduced at EOL. Sell IR matched sets of 93 cells (5 spares). Confirm quality with high grade equipment to measure IR and include a report with every set. Crate them up and you will get orders. $3500 per set plus sea freight.

I'm so surprised that this hasn't already been done. Seems like there are tons of generic "Catl 94Ah" cells of various dimensions close to but not including 171/44/98. Make an exact copy and you will be off to the races! I have OE Yuasa cells to send you if you need a template.

that would be a cherry on top of the cake! i would order 90 cells (just in case) on the next day!
I'm still trying to find out to "fool" the CAN to make the bateries fit the spec!

 

[CeeJay09]

that would be a cherry on top of the cake! i would order 90 cells (just in case) on the next day!
I'm still trying to find out to "fool" the CAN to make the bateries fit the spec!

I ordered 8 of these SVolt cells and tested them recently. The test was between 4.1v-3.3v to measure the capacity in an imiev with no CAN bridge. the cells ranged from 68.5AH to 71AH at a constant 30A load. I am in discussion with the suppliers to have these cells fitted with lazer welded tabs that mimick the cell tabs on the imiev. I will upload the files for the 3d printing files for the spacings and any clamping methods I come up with for these cells. I hope that I can get someone to assist me with accessing the remaining capacity from 4.35v-2.75v once this is completed

 

[CeeJay09]

I ordered 8 of these SVolt cells and tested them recently. The test was between 4.1v-3.3v to measure the capacity in an imiev with no CAN bridge. the cells ranged from 68.5AH to 71AH at a constant 30A load. I am in discussion with the suppliers to have these cells fitted with lazer welded tabs that mimick the cell tabs on the imiev. I will upload the files for the 3d printing files for the spacings and any clamping methods I come up with for these cells. I hope that I can get someone to assist me with accessing the remaining capacity from 4.35v-2.75v once this is completed

I am in the process of testing the full voltage range capacity and will post those results once complete

 

[MickeyS70]

I hope that I can get someone to assist me with accessing the remaining capacity from 4.35v-2.75v once this is completed

There are several good reasons why EVs don’t use the full cell voltage, safety and cell longevity to name a few…

 

[JoeS]

I ordered 8 of these SVolt cells and tested them recently. The test was between 4.1v-3.3v to measure the capacity in an imiev with no CAN bridge. the cells ranged from 68.5AH to 71AH at a constant 30A load....

Thanks for doing the tests. I, for one, would be delighted with 70Ah at 4.1v max/cell.

 

[MickeyS70]

I am in the process of testing the full voltage range capacity and will post those results once complete

CATL93 have around 87Ah within the triplet ‘range’ using OEM recommendations.

More important than capacity imho, how are you planning to deal with the excessive height of the cells, they are fitted sideways iirc and 5x4mm (25mm worst case) of additional space might be tricky to find?

 

[JoeS]

Thanks for doing the tests. I, for one, would be delighted with 70Ah at 4.1v max/cell.

I forgot to include "...with a form factor identical to LEV50/LEV50N"