Prius Battery Replacement Kit (GenII/GenIII) with NEW custom cells

Late to the party, this is a terrific solution. Your models are the same as two, 7.2V modules tied together but with the advantage of much more surface area. Heat is the enemy and this solution suggests a much improved cooling flow.

There are three temperature sensors in the OEM battery pack. Where do they go on this pack?

Are there any intra-module, baffles to ensure the cooling air passes by all three cell strings?

For @ericbecky, given past heat issues, I would recommend a through heat stress test in the future. It doesn't take high ambient temperatures but doing high-speed, maximum acceleration up and down a reasonably tall, steep hill and turning around and descending in "D". The hill climb will bring the SOC down and the descent in "D" will put a charge back in, the exothermic event. It is called 'heat pumping' and puts the maximum stress on the battery.

I would recommend using something like TechStream to record the battery temperatures. If @2k1Toaster can point you to the cell data sheet, you can track the temperatures against the cell rating. It helps if the cooling fan comes on as a 'stopping point.'

In an ideal world, every stick would be instrumented but that can be expensive. As a workaround, a non-contact, IR thermometer would work. Just have the top cover loosely attached so it can be quickly pulled. Heat pump the pack and then scan the sticks looking for the hot spot. Rig up a cell phone video recording on a duct-tape and sticks fixture and survey the pack.

Kudos for the design and approach. Well done!

Bob Wilson

 

Eric! Those pictures are cool. The deltas between individual blocks is just so tight. Nice one there.
Can you make a graphic presentation using ithe tech stream or the hybrid assist app you're using?

 

Are you limiting your speed due to the battery or something else?

 

No reason other than I'm just not much of a speeder and the roads I commute on have lower speed limits. Generally speed limit of 55 or 45.

Occasionally I'll do some interstate driving. There the speed limit is 70. And you will generally see me in the right lane because... Well... I don't generally feel a need to go beyond the speed limit.

 

I know I'm being greedy here, but theoretically speaking, if there was a 2.0 version of these cells that would be able to have noticeably more Amp Hours or capacity, would that mess with the BMS and ECUs of the car - or would it be a viable way to improve our cars? Of which for the most part modding is incredibly restrictive outside of chassis and suspension.

A man can dream, right?

 

The Prius ECU simply doesn’t care. It follows the same W-hr discharge and charge capacity range no matter the ability to go beyond that.

 

I think that might be because of the battery chemistry(NIMH), or what?

What then happens if its a Li-ion? Won't there be some impacts on the electronics? Aren't there a certain voltage/amp-hr thresholds for the BMS, etc?

 

On the sidelones, is the voltage capacity of the newly installed pack motr than the stock one? What happens to the battery ECU, and all that? Can the hybrid system cope with the increased voltages and amp-hrs? I do know, more juice, equates to more range.

 

It is usually not good to change or mix battery chemistries. The charger is designed for a particular battery chemistry. Getting it wrong can let the magic fire & smoke out.

 

I'm referring to the newly installed NIMH cylindrical modules.
Is the newly designed pack of the same total voltage(301..volts) as the stock prismatic pack that was removed from the car? That's my concern

 

Do you think you can mix your new modules along with OEM ones for those who like to play "Whack-a-mole"?

 

Could you sell/ship to customers in Canada?

 

Thanks for the reply. That was what I was thinking. Thought you had more cells in there, than the stock HV battery pack.

 

Hey everyone, I haven't posted on here in a while. I have been doing mobile H/EV repairs for 2 years (10 years on ICE vehicles) and I am opening a shop December 1st. that only works on H/EV. I am very happy to see that someone has finally made this happen and I am very hopeful that it works well. I really hope this works because I have numerous customers every month that need packs installed and new OEM packs are just too expensive; it basically financially totals the vehicle. I will be ordering one of these for a gen 2 to experiment with. If all goes good you can count me in on this. Right now I get at least 5 inquiries per month for pack replacement. I rebuild packs but i've been looking for a good new module replacement for a while.