Changing NiMH Battery to Li-Ion- Gen 3 Prius

Given the difficulty and expense, what gain to you expect from this? (i.e. mpg or cost savings)
And what about the 100K or 150K warranty that you'll be giving up?

Mike

 

1) yes

2) yes

1) meh

2) meh

3) meh

1) meh

2) not worth the paper it’s printed on

 

If you're doing it for the fun of it or for the challenge, then have at it. If your goal is :

1. Lighter weight. Better handling and fuel consumption
2. Higher energy hold
3. Better Charge rates.

Then you'll never see the paypack on it.

I've thought many times of buying a Gen 4 LION battery just for the fun of it to see if I could build a Gen 2 model for our spare 2005. Plenty available out there at the $1000 range but I'm having a hard time pulling the trigger on something that may end up just being a Frankenstein paperweight....

If you do this, keep up with progress posts on here. I'll certainly keep reading.

 

Any problems with your current battery, is it dying? If not I would definitely leave it be.

 

A straight out retrofit would need a whole new charge and monitoring system while maintaining the same power to the motors and ac systems to retrofit. Which would involve a dramatically different inverter converter, not one out of any existing car. The old battery has its own ecu and monitoring which would have to be mimicked on the network as well. Maybe a supplemental lithium pack with its own charge controller and monitoring. I suppose someone could rip out the existing cells and replace with lithium by ensuring the existing battery ecu saw the same 201vdc and maintained the same number of voltage monitoring points in the battery even though lithium volts per cell is not the same. All while still requiring a supplemental lithium charging and safety system built in. I think you are better off with existing aftermarket NiMH cell strategies in the same battery enclosure. Or buying a newer model built for lithium which, in itself, is a more dangerous battery requiring a high level of quality power electronics engineering.

 

Whatever battery cells you choose will need to handle 130 amps discharge. Unless you have a parallel configuration. If fitting into the existing case, you'll need cells with the correct dimensions to pack in without crossing the bus bars. They should also handle the temperature range at the max current discharge, etc.

Without fitting all your cells in the original case you'll then have to invent air foils and add fans, etc. It can get complicated.

 

Being a skeptical, link me to those posts. I am serious.

 

I think we get this idea/post once or twice a year from new members.

 

yup

 

Clearly there are not a "lack of folks" willing to try. They tried it and found it was not worth the effort. There were blow by blow threads on this site as they progressed. Lithium chemistry must be charged and managed differently and there is a whole interconnected network of ecus and software which must be functional with any changes or the car won't run. The others did match the Prius battery voltage and charging algorithms without lithium. They were costly and provided little return for the money. The real benefit of lithium is its lighter weight and increased energy density. The problems here are cost, compatibility and fire danger. The Prius battery cooling would have to be improved, probably with liquid cooling as most other ev use these days. To get enough lithium to gain ev range might be a thought, but the Prius ecus won't allow useful ev operation other than low speeds. Bottom line: if someone can cost effectively retrofit new lithium packs in place of the Prius systems for less than $2000, there might be a business case.

 

Not to sound closed minded but post #15 sums it. Back in the day, when nickel cad battery were it, then nimh was the next thing when it came to AA, AAA, D C batteries. Nicd chargers couldn’t charge nimh ones. Plug in play, it required a whole new charging system so everything had to be reenginered. Warning label said don’t charge nimh cells with nicd charger with fire flames icon warnings.

 

#15 "Bottom line: if someone can cost effectively retrofit new lithium packs in place of the Prius systems for less than $2000, there might be a business case."

revisiting an old post, but looks like it has now been done - by Dr. Prius app guy - Toyota hybrid battery upgrade pack– Lithium Prius

 

not yet, but hopefully. as far as a oneoff, it would be an expensive, time consuming endeavor.

which is why, like all of these threads, the o/p never returned.

apparently, he is not a wright brother, or goddard