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 .
