The Gen 4 Prius models all have Li-Ion other than the Package 1 which uses NiMH due to costs. What is the process of changing NiMH Battery to Li-Ion? Being a Mechanical Engineer, I know there's a way. And I've seen many posts of people adding additional battery packs to their Prius to extend range. Questions that come up 1. Software changes? Are there any needed. 2. Cable connections to Li-Ion pack? Benefits of Li-Ion to NiMH 1. Lighter weight. Better handling and fuel consumption 2. Higher energy hold 3. Better Charge rates. Issues with Li-Ion 1. Really cold weather. Like all batteries it becomes bad. But being from Texas, that's 3 months out of the year. So not worried about it.
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
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.
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.
Don't mind giving up the 100k warranty. Have seen the Gen 3 batteries hold up very strong to those miles. Don't see the difficulty as a problem but lack of information provided out there, and lack of folks who are afraid to try something new. Think it won't bring the cost benefits for sure, but believe it would be a nice project to learn and see what it brings in results in helping others in the group
There are a ton of videos out there. Just google search and you'll see. Only issue is most of these companies have gone out of business. So it's doable but the education is now gone.
Human beings also asked similar questions in the past regarding going to the moon or flying. The question still got asked by "new" people, many failed, but due to it being asked many times over many years, there became the ability to achieve greater things.
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
