Prius Battery Replacement (GenII) Like you've never seen - NEW Cylindrical Cells

Some will install a new pack only if you buy it from them. You cannot buy a pack elsewhere and have them install it. You cannot just take the pack and install it yourself. And since the dealer price for any part is suggested by Toyota but can be set to whatever they want, that's one cause for the large price differences you see posted. That plus the shop rate and extras make the total cost variable.

 

You miss the part where I said "some"? That includes my two local Toyota dealers though. And if you read just above as to what I was replying to, you'll see a valid expert installer was denied a hv pack from a dealer so went to another.

 

The skeptic in me says that most of these stories are like this. Not just with hybrids. Go in and there is a multi-thousand dollar repair bill, but the dealer is willing to pay you more than they have convinced you the car is worth if you trade into a nice new shiny car. And people fall for it all the time unfortunately.

 

Yep, good for a quick fix but that's about it.

"No vents" is again a simplification. Venting occurs when the battery is overcharged for a prolonged period. If the battery is overcharged slightly, some excess hydrogen and oxygen gasses will be formed within the cell. Forming these gasses is how a NiMH cell charges. The water in the electrolyte separates into hydrogen and hydroxyl on the negative plate. The hydrogen goes back into the alloy. When discharging the hydrogen desorbed back into the hydroxyl making water again. Different reactions on the positive plate, but not important to this. If you charge the battery too fast hydrogen is created faster than it can be absorbed back into the alloy. A battery can take some that extra gas as the pressure increases. As the pressure gets too high, the cell explodes if there is no vent. A flat design like Toyota can take less pressure than a cylinder before deforming permanently. When this happens, the magic cannot be put back into the cell.

Having said that, these cells do vent. But they are not controlled vents. Venting only happens during some time of catastrophic event. The HV ECU makes sure to baby the battery, that's why they last so long. On the Toyota cells, the extra hyrdrogen and some oxygen gasses go up the vents into the tubes and down and out the car. On these, the vents are designed into the "bump" ontop of each individual 1.2v cell. Each cylinder has a vent. But it is activated at higher pressure and the gas escapes into the main battery chamber, no special vent tubes. Since it rarely if ever happens on the normal cells, it should absolutely never happen with a cylinder. If it does, there is something else terrible happening and that is most likely one of the least of your problems.

Ceba manufactured the plastic as in they contracted it to an outside plastic injection company. Moulds were modified as improvements, and Ceba's contractors used. I am being told they may use the improved parts in their kits now too.

And yes a different Chinese company used different batteries to actually get 6.5Ah in a cell. I do not want to divulge the manufacturer at this point. First rule of East Asian business is keep your contacts to yourself. This battery manufacturer takes the cells, wraps them in the PVC skins, welds the ends of the row interconnects, and laser marks the tops. These are packaged and freighted to some space in a warehouse I use in China. Ceba sends the plastic-only kits to this warehouse. I have some people put it all in small boxes on a skid pallet, wrap it up, and send it out. For now I have been doing everything air freight since there are no restrictions for NiMH batteries in the cargo holds of planes like there are for Lithium batteries. Nothing is done in the US except for the final sale at this point.

There are good Chinese manufacturers and cheap Chinese manufacturers. Just like the USA. Generally people buy Chinese made knockoffs because they can get them cheaper. China is not a cheap place, it has a very high standard of living in these industrialized areas. It is not the 1980's anymore. If you want cheap to buy, it is also cheap to manufacture, usually meaning cheap in quality.

The batteries I get shipped to me are tested at the manufacture individually before sleeved and welded. The test process is a lot sooner in the assembly than at the end looking at individual modules. I have looked at quite a few of these modules in person and remotely. The wonders of the internet is a laptop with some lab eval equipment can be hooked up to hardware on the opposite side of the world and data can be had live. The failure rate of the modules should be low as they are pre-selected before being built as a module. Early cell failures won't characterize properly, won't be made into a cell, and wont end up in a car. It would have to be a cell that passed QC in a few places where it shouldn't have or suffered damage after manufacturing. These are not things that can be measured with such a small sample set.

Cost is roughly $100/module at this point for a brand new module. Obviously if I have surplus ones from testing those would fit into a used pack better.

On the stock pack, battery sensor #2 is usually the highest. And it is at the center of the pack... <cough><cough> When you get into the 50C range, you're cooking it good, and that's bad.

On the strenuous runs, the packs get up to 50C. The fan is whirring as loudly as possible. The more relevant data is the time it spends superheated. On the stock pack basically once it heated up, it stayed at the higher temperature dropping a almost nothing on some downhills after fully charged. It would take a couple minutes of being parked and stationary before the fan would start to turn down from max rpms but it would keep running. With this pack it was easier to see where the pack gets hit because almost everywhere on the way down by halfway down the fan would audibly change lower. And on the way up, it takes a few seconds before it kicks on again.

Now keep in mind, unless you live in the Rocky Mountains, you won't really have this type of environment. 6%+ grades at 80mph up and down. A few miles up, a few miles down, and repeat for a couple hours if you want. And of course some roads are 80mph then sharp braking to a 10mph switchback then back up to 80mph. The battery hates this.

I can also get the temps up to max fan temps with high speed and hard acceleration driving. We have 75mph speedlimits in lots of places, again not "normal" for the rest of the country. And even the flat spots gain and lose 1000ft of elevation every few tens of miles.

In normal city driving I noticed about 4C to 5C cooler temperatures for the same drives. But that doesn't really mean much. It means more in the extremes which is not which gets hotter but which cools down faster.

 

As I've said many times, direct evidence contradicts what you're saying. You have done no such testing so maybe it is you you should go away until you do some research and testing. As far as I know, you're not one of the 3 factory owners in China with this system. I am fairly confident you are not me. That means you do not have any of these cells let alone any of these cells installed in a Prius and have driven real world miles with it.

Out of the 2 of us, only 1 of us has real world miles and that is me. My evidence shows that your calculations are wrong. The many posts on here about the thermals of the pack (sensor #2 being higher) and the higher failure rate of central modules, also support my claim.