This question is prodded by having recently paid a well-known Indiana Prius recycling business (ABY) to replace the traction battery in my daughter's 2010 with a new Toyota one. The process went well and quick and I was on the road headed back to Indianapolis within an hour of arriving. While he worked on the car Steve talked (as he is known to do) mentioning that Toyota in the past year has dramatically raised the price of new Gen 2 and Gen 3 battery packs. If what Steve cited is correct, the price increase represents predatory behavior by T whose purpose is clear: to flush remaining old Prii off the roads. No way that battery pack needs to cost that much. PrimeEarth's tooling was long ago paid for. I have watched with a bit of amusement the growth of the hybrid battery refurbishment industry over the past few years. 13 years ago I tried a couple of refurb'ed batteries in Prii and the experience was underwhelming. In those days refurb shops had no equipment to "treadmill" the cells and determine which ones had remaining life. The term internal cell resistance was never mentioned in ads or reviews, probably because there was little equipment to measure that parameter and the folks doing the refurb'ing generally have little technical training. Today it appears the refurb'ers use repurposed charging hardware designed for radio-controlled airplanes and cars. Technically trained people have even networked these hobbyist chargers and can today operate them from laptops and provide charge/discharge curves for cells. But I've noticed that the home-brew treadmill apparatus sold on the internet assumes that the Prius battery pack has been disassembled down to its individual cells. While the battery stack is disassembled and its cells exercised, their dimensional thickness changes and reassembling the battery stack into its compression frame can be difficult. As a practicing electrical engineer who designs and builds circuit boards for a living it occurs to me that it should be possible to "treadmill" cells and sort them by discharge capacity while they are still bolted together in a stack. In other words, it should be possible to acquire detailed data about each cell with them still compressed in Toyota's factory frame and bus-barred together. Doing this could be riskier from a safety standpoint because the cell stack's normal voltage is greater than 200VDC, but lots of consumer electronic hardware contains unsafe voltages from which the user is adequately protected. The known protection methods are line operated power supplies designed with double isolation and enclosing the entire sub-assembly in a well-designed polymeric housing. Is what I'm I describing (a line-operated battery charge/discharge device tolerant of high common mode voltage) something that has already been designed?
Yes, you can get the entire pack refurbished, charge and discharged quite easily. Hybrid Automotive was one of the early adopters of this, since then there may be better and more reliable equipment than what they are putting out. It's not necessarily accurately measuring the remaining capacities of any of the modules, but to recondition them by discharging the modules to a really low voltage then recharging them back up....doing this for a few cycles will recondition them and bring the modules back to a healthy balance again.
Oh you're not going to get down to the cells unless you're going to cut hermetically sealed prismatic modules be interesting trying to plastic weld them back together .
Im an electric engineer as well. I also happen to work for a Toyota plant and was hybrid system trained many moons ago where they attempted to scare us away from ever attempting to do exactly what you are describing. Well, im currently looking to do exactly what you are describing as I dont scare easily. I've built a battery charger/discharger (because im too cheap to buy one). I've actually not had the time to test its function but looking forward to it. I said all of this to 2nd what JC said. Regarding the acquisition of cell data from the pack without breaking it down, I don't know how this would be possible without 1st installing electronics and hardware within the pack itself. I dare say that if it were already capable, the dealerships would be using this technology. If this is something you were to design, and build, I bet you would make a killing as every handy hybrid owner would know in real time, the condition of their battery. Let me know if im way off base.
Techstream actually has a bunch of information you can pull while the battery is in the car. It just doesn't break it down to each individual module. It does it in blocks. But there are apps available that can generally give you a decent idea of the condition of the battery block. Anything professionally built is not worth it for the home user, the PLC equipment will cost thousands to monitor the battery. Just better off buying a new battery and call it a day. The best testing tool to use is probably the car itself. As it throws 100a at the battery. If there is a problem module (when the battery SOC is low), it would fail quite quickly with 100a thrown at it.
I think the first questionable assumption is a recycling business installed a new battery. Assuming a reconditioning outfit restores bad modules is not true either, bad modules are replaced with better used stock. Life of the rebuilt assemblies is still short unless they actually installed brand new oem nimh modules. The idea of individual "reconditioning" old modules in place seems difficult but not impossible if you are willing to install isolation devices between modules and individually switch each module into and out of the circuit for a "reconditioning" attempt by automated equipment carried in the trunk. I think it would be easier to install a set of the cheaper cylindrical nimh cells and have the same net result, eg a lower cost - albeit temporary, solution than a dealer offers. Of course there was a company doing just that with cylindrical nimh but reliability issues and short lifespans sullied their reputation.
cylindrical solutions that have been pushed here on Priuschat have only lasted about 3 years, they are not very good. And the guy pushing those batteries no longer come to the forum anymore, claiming he has so much business he can't keep up with us little guys. Bunch of BS The recycling business is probably AutoBeYours, they seem to be good at what they do, been in the business long enough to do a decent job with the Prius recycling business
I cannot believe there's so much BS with batteries going thru similar w volt ELR crap. Bunch of nonsense can do companies out they're cannot be hard to fill three rectangle shaped boxes w modules and two cooling passages you'd think . He he . Oh well few more years.
