How to improve the heat dissipation of high-voltage batteries

Stop.... don't waste your time on a pitty party.
If you read the threads, everyone who only replaces bad block has the same issue.
Green bean seems to be the worse. Even using the Prolong system is a not a permanant fix.
Sometimes you have to do what you need to do with the finances you have.

At best you are doing a temperary patch. If you enjoy doing it, keep doing it. If you are doing it
to try to save money, you'll end up spending more that a new battery. But you are also using
a lot of time and work each time. And you risk getting stranded at the worst time.

 

Don’t apologize for advocating good forum behavior. In the end you are just like a majority on this forum; diy to save money and gain a sense of satisfaction. Some need to do it but most simply want to save a new car payment so they can have a big house and more grown up toys.

Many of us have wives or children who commute to work or school every day in all weather conditions. Reliability is important. We may live 45 miles out in the country or commute through an hour’s worth of traffic.

So for that small group of active Prius owners, new hybrid cells provide peace of mind and the new cost is small relative to our resources. In fact, a new hybrid battery is often less than three new car payments and the insurance does not go up.

In exchange for hours behind the wheel every week, we are often paid ten or twenty times the salary of someone in Fiji. We think we have escaped big city crime and we know the hybrid battery is the least of our problems for ten to fifteen years.

Odds are few if any Fiji wives or children are commuting to work on 70 mph freeways like Americans routinely accept as part of their normal.

 

You do know ALL the blocks will (should) charge to the same voltage? They won't stay at 6.4v.

 

???? That makes no sense. How are YOU charging the battery while you're driving?

 

Interesting thread.
Our OP, James, in post 23, indicates he found and repaired ducting issues.

FWIW My initial thoughts to answer this question was to increase air flow in and out.

 

I've read this thread and understand it well enough, I'm very familiar with Grid charging at the pack level. I'm not experienced with Grid Charging individual modules, but I've read a lot about how it's done. There are six individual cells in a single module. There are 28 modules in a Gen 2 or Gen 3 Prius pack.
Many people that post to a thread about how to maintain a battery pack in haste or misunderstanding will call a module a cell. It's extremely confusing for everyone, and many of us make that mistake. No worries, as I leaned how to keep my NiMH packs working in my hybrid, I ran into many many misused terms in descriptions and have leaned to read between the lines of the actual words. But in the beginning of learning that is the most frustrating part.

I think what others posting above are trying to explain is, in my words - that modules in the middle of the pack are know to get warmer / hotter than the modules on the out side ends of the pack. One way of minimizing degradation of this issue is, After grid charging and balancing each module reassemble by moving the center modules to the outside ends of the pack while moving the modules on the outside of the pack to the center.

There is a concept called "the memory effect" that is obvious with ( NiMH cells, modules, packs ) when cells or modules or packs get out of balance. The grid charge is used to reduce the difference in charge and discharge capacity.

If we could grid charge one cell at a time, we would be able to see on out volt and amp meters which cells were out of balance and the capacity of each cell. And we would be able to, with a little luck, be able to balance the modules more closely.

Most hobby chargers with charge one module at a time and do there best to give as much data as possible regarding how each cell in the module is performing. But that is not always as accurate as we'd like it to be.
This quad port charger will charge 4 modules at the same time and there are a few Priuschat members that own this one.

Same is true to an even greater degree when grid charging at the pack level, even with a very expensive and complex machine built for that task. https://99mpg.com/projectcars/gridcharger/

available from Hybrid Revolt Hybrid ReVolt Smart Grid Charger [HR-GC1] - $799.99 : HybridReVolt: Hybrid Battery Repair

The difference is the time spent on one cycle gets reduced at the pack level in much the same way as the time to cycle a module is greatly reduced than triing to cycle each of the 6 cells in a module.

I hope my post is not to difficult to read for a non english reader.

 

When you charge at the settings you posted above, are you almost monitoring the modules temperatures as the modules are charging and discharging? Using a fan to help in keeping the modules from heating up is recommended.

Also, Monitoring the battery pack behavior while being used in the car is just as important as monitoring the charge discharge cycling. In My Opinion DrPrius is by far the best app for real time data of the Gen2 and Gen3 Prius pack data.

 

Balancing the pack at its low voltage sounds like an interesting process, especially while cycling older modules.
Some others have gone as far and matching 2 modules with each other to form a block so there would be 14 blocks in the pack. Just another way of cycling and assembling a pack that some have found useful.

Here is youtube about how one hybrid mechanic balances his modules after cycling to add a final test before reassembly. I'm sure he also monitors module surface charge and self discharge besides what he shows in this video.

Yes, off-gassing, loss of electrolyte is never a good thing for any battery.

 

Let me correct this for you. , although Toyota's charging and discharging strategy is 40%-80%

The internal combustion engine turns on to charge the hybrid battery at 40%.

 

Is that a misspelling in the graph text?





yes it’s a joke

 

I see, yes it must be very difficult and frustrating when in the car and the pack voltage drops like in those screenshots.
I also have 3 packs for a 06 civic. And they are all in a similar state as your prius pack appears to me from my observations and your descriptions. I also struggle with how much to spend on batteries for my gen 2 civic hybrid for several reasons, mostly due to the difference in the cars assist and regen after it's last service at 110K miles.. The cars Honda Update, new programming is even worse in the winter when it's freezing cold, than when temps are milder in the summer and fall.

The car assists at very low / freezing temps as soon as I touch the Go Pedal. It's extremely frustrating and I'm sure that assist during the cars warm-up cycle is not to friendly to my old battery packs.

 

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