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

An interesting design. From my own calculations these modules look like they'll have 50-80% more surface area to dissipate heat compared to Toyota's prismatic module. The cylindrical design might allow a more even dissipation as well.

Do these cells have relief valves for exhausting hydrogen gas? What are the temperature ratings and pressure ratings of the cells?

 

I may not have expressed myself as clearly as I imagined - the heat that I'm referring to is due to the car simply sitting in the sun somewhere hot (e.g. Phoenix during the recent heat wave) since simple exposure to heat (and operation after said exposure) is hard on batteries. After sitting parked in the sun for a few hours, I'd imagine both of the batteries would both end up the same temperature (basically coming up to the ambient temperature in the car) since there's really no active temperature management when the car is off (can the battery cooling fan run when the car is off? I'm not sure on this). The early Leaf batteries and their relatively precipitous range loss in hot climates might be a good example here.

While I understand that engineers are somewhat protective of their projects, I am a little surprised by your defensiveness on the fact that the millions of stock batteries in existing Priuses provide some confidence. I agree that research and initial engineering is critical in developing any product, however I have a really hard time so easily dismissing the very real data that these packs "in the wild" provide as part of a larger development cycle (and I'd be shocked if Toyota were not tracking the performance/longevity of these vital components in service).

 

I think it's great 2K1!

What could possibly be greener for the planet than giving a Gen2 Prius a second life? That saves a lot of resources since you do not have rebuild the whole vehicle.

I wish we knew more about Gen2 Prius life data, how many % batts died for each model year etc.
How many Prii got back on the road, how many junked, how many used Prii/exported

Wonder if 3ProngPaul is still around...he might interested.

 

Very cool project. Great to see innovation in this area.

Bravo!

 

@3prongpaul was just here recently.

 

I sent him a message through other channels to be sure he saw what 2K1Toaster has put together.
An upgraded version of the Ceba setup.

 

You just aren't getting it.
It is the whole overall tone of the post.

I don't remember seeing you post ANYTHING on here for a long time......maybe EVER.
Note that I said I don't remember you, not that you weren't active at some time in the past.

The first post from you that I notice is a lengthy "sales pitch".

I've been around for a LOT of years and the overall tone of your post struck me as sounding like somebody hawking snake oil........kind of like "Too good to be true."

Since others on here seem convinced that you are 100% legit, I'm sorry that I made any comment at all.

 

Interesting.

YOU have developed them?

I know it's been posted before, but I just have to repeat it. It's amazing how they look EXACTLY the same in every way... right down to the fabricated pieces and the spot welds.

and here...

Ceba New Design Product For Prius Gen.2 & Gen.3 - Buy Car Battery For Prius Product on Alibaba.com

You are claiming invention 5+ months later, or does you buying the guts and offering them for sale as a kit count as "development"?

And you're fighting off these bits with claims that yours is somehow different.

If you have such faith in these, why are you charging 80% of Toyota list yet offering no warranty? Even Toyota gives you a warranty.

There are multiple reasons Toyota went with prismatic modules. Reliability of the Gen0 Prius in Japan using PANASONIC "D" cells was poor. This has also been evidenced by the failure rates of Honda IMA "D" cell battery packs presented here:

Consumer Reports Blasts Honda Civic Hybrid Reliability » AutoGuide.com News

2015 Subaru Outback and Legacy | Video Review - Consumer Reports

Note that the above failure rates are for Panasonic and Sanyo produced cells. Not some no-name (Ceba/EnnoPro) Chinese company.

Here are some facts associated with claims made by the OP:

1. New Toyota packs rarely sit on shelves for more than a few months unless you're in a remote location.
2. The typical failure mode of a Prius pack is a single cell.
3. Two six cell subpacks are no more prone to failure than 1 12 cell subpack, BUT
4. More cells per subpack means that more cells must be replaced when ONE cell fails. With prismatic, you replace 6. With the proposed, you replace 12 (note the higher failure rate of the 06+ Civic vs. 03-05 Civic referenced above - 12 cell vs. 6 cell subpacks).
5. Prismatic modules have a high surface area to volume ratio.
6. Prismatic modules have a thin cross-sectional area meaning heat produced in the center has less distance to travel to the heat sink (air).
7. Prismatic module cells have a very large portion of their surface area directly exposed to airflow.
8. Per NASA: Cylinders have poor aerodynamics, and they create extremely turbulent airflow (please scroll down to the "flow past a cylinder" portion). Drag of a Sphere. Tesla uses cylindrical cylinders because that's what was available at the time, 18650 cells.
9. Per the above, it is nearly impossible to get uniform flow across the entire surface of a cylinder unless the flow is very slow - uneven cooling.
10. Stacked cylinders will flow worse than single cylinders.
11. Cylindrical cells have much thicker cross sectional area (1.5-2X). Thus, heat produced in the center has MORE distance to travel to the heat sink (air).
12. Honda packs are notorious for cooling issues, and they have well spaced subpacks. Some models are staggered to improve airflow (still doesn't help per the failure data). Honda fans are dramatically more powerful than Prius fans requiring 9A/12V to run at full blast and are like a leaf blower. Prius fans will run full speed at 2A/12V.
13. Honda pack temperature readings are about 5-10°C lower when the car begins to cool the pack aggressively. This is because the core temperature is much higher than prismatic modules, and the cooling is less effective.
14. The cylindrical Prius pack has closely spaced cylinders vertically and loosely spaced cylinders horizontally, this dramatically affects the airflow, and none of it is positive.
15. The battery management system is designed for prismatic modules of approximately 0.75" thickness with a large plenum and restricted exit for high velocity airflow.
16. Given the poor airflow of cylinders and the unmodified cooling system (same computer, same temp harness), the cylindrical cells will operate at higher temperatures than prismatic modules - particularly at their centers, and the cooling system will not be as effective.
17. Lastly, prismatic modules share a common air space with six cells. During operation, the electrolyte exists in part as a vapor and can transfer from one cell to others in small amounts based on their saturation levels. This has been one of the key factors in the high reliability of the prismatic module over cylindrical cells - it behaves like 28 isolated cells more than it behaves like 168 isolated cells. When an isolated cylindrical cell vents, it's has lost a small amount of capacity and increased its internal resistance permanently.

There is no objective evidence that suggests the cylindrical option is in any way superior to the prismatic modules.

Given the compromised cooling system, it's likely their failure rate will be higher than Honda.

Given that they are Chinese made cells vs. Panasonic or Sanyo, their failure rate will likely be higher than Honda.

Cylindrical cell vs. prismatic cell data shows the cylindrical cells have a higher failure rate (Honda vs. Toyota).

Data showing failure rates of 12 cell subpacks vs. 6 cell subpacks shows a higher failure rate in 12 cell subpacks (Honda vs. Honda).

Note again that all data presented is for Panasonic and Sanyo produced cells - NOT Chinese CEBA/EnnoPro. Japan generally has a better reputation for quality, no?

And to whittle it down to TL DR:
12 cell subpacks fail more often than 6 cell subpacks.
Cylindrical cells fail more often then prismatic cells.
Cylindrical cells installed in a system designed for prismatic modules will run hotter.

All cons.

No pros.

Good luck.

 

Can't you just rely on your reputation on this site? "I'm a good guy, and everybody here knows me. If it fails inside of 12 months, I'll give you your money back if you ship the guts back to me. I promise." Heck... I think you would welcome that scenario, as you would acquire reliability data.

But no... "$2000 for my Chinese knock-off with no warranty."

17 points dismissed with a feeble "real world testing refutes... blah blah blah"? You should probably consider getting specific because they are simple facts, and you really should strive for credibility when you're hawking something with so many obvious strikes against it.

Post your real world testing so you can back up some of your claims. I've scrolled back through the whole thread, and I don't see any hard data. An unsubstantiated claim of "real world testing" is meaningless.

Carl Sagan popularized it... "Extraordinary claims require extraordinary evidence." No evidence has been provided... let alone anything extraordinary... more like.

Claim: "Better than the technology in cars with 300K miles on them and 13+ years of history".
Evidence: "Trust me. I'm working with the Chinese on this. They're cool. BTW... look at my post count."

If your real world testing was so promising, I can't believe you aren't showering us with it...

Concerning Honda, depth of discharge was only one factor in the design, and this was patched in the 06-11 civics. Their batteries still drop like flies. While the battery management allows for down to 20% this is rarely seen and the car aggressively tries to maintain > 50% SoC. At least according to to Peter Perkin's OBDIIC&C on my Insight.

I question your understanding of the Prius cooling system. The fan is on nearly any time the battery is over about 90°F at least according to my Torque Pro with the Prius PIDs and lots of recorded drives. It doesn't take much to get a battery to 90°F and higher.

Where is your comparative drive data? Where is your evaluation data after X months/years/miles? Are you alleging that your bench testing accounts for all the varied conditions in various regions? What about the regions where temps are over 100°F for weeks/months at a time? Where is your reliability data?

With all due respect, put up or shut up. Even your post count can't offset your lack of credibility in this matter.

 

Just in case I missed something, I went back over your original post. Rather than substance, it's all unsubstantiated claims with a clear marketing slant. Claim after claim about unsubstantiated superiority.

Battery acid on your case? What? You know that these don't contain acid right?

I saw you clarified later but really... "cells" 28 "cells" vs. 14 "cells"?

What I find most interesting is with all your efforts to obfuscate the origin of these cells... That first letter could certainly be a "C".



Those last two letters sure look like "BA":



Who doesn't make these again? CEBA, right? "C BA DEFINITELY DOESN'T MAKE THESE. SOMEBODY ELSE DOES! SERIOUSLY. I PROMISE."

Good job. One out of four ain't bad.

Next you'll be telling us that these are stock photos, and somebody else tried to pixel out the origin, right? CEBA doesn't make YOUR sticks... yours are better... YOU developed them. Totes.

 

Profit, yes. Community benefit, oh my goodness, no. Unless "community" is a nickname for your bank account or your LLC/corp. Then I would totally agree.

You have made multiple unsubstantiated claims that just drip with marketing BS, incorrect terminology and just plan... wrongness. Silliness about acid in batteries, silliness about some benefit of a 12 cell subpack vs. 6 cell subpack.

I have presented a wall of factual statements that all indicate your proposed configuration is disadvantaged in every way. You dismiss them with a wave of the hand as though they aren't factual. It is in fact you who is acting like the climate deniers... .Climate scientist: "here look at all this data supporting these conclusions/conditions", Denier: "no. that's wrong. I have other data I can't show you. Besides, it doesn't even warrant a response. Look, I have clean coal for you over here. You can eat it. It's healthy."

Put up, or shut up. Give some sound reasoning instead of a bunch of marketing BS.

I eagerly await either the bonfire or the data. Your choice. I predict a previously unforeseen/unspoken 3rd (or more?) option(s) will emerge...

 

On what do you base your calculations? It's late, and I'm tired, so I might have made an error... but...

"D" cell exposed surface: 33.2mm dia x 61.5mm tall = 33.2*pi * 61.5 = 6415mm^2

You don't get to count the ends because they're welded to each other.

prismatic "cell" is 42.3mm wide. 105mm tall and 18mm thick.

42.3*105*2 sides = 8820mm^2 + 1522.8 top and bottom = 10,322mm^2

VOLUME of a "D" cell is 53240mm^3
VOLUME of a prismatic cell is 79947mm^3 (most of the extra volume is the air space above each cell)

So, for every cubic mm of volume, a D cells has 0.12mm^2 of surface area
For every cubic mm of volume of a prismatic cell has 0.13mm^2 of surface area

The prismatic cell has 8% more surface for its volume.

Heat transfer can't be ignored. The core of a "D" cell is 16.2mm from the closest cooling surface.
The core of a prismatic cell is 9mm from the closest cooing surface.

Please refer to the linked NASA page for the airflow characteristics around a cylinder. See if you believe it is an improvement over flat surfaces that are directly aligned to the airflow. If you still think it's an improvement, don't forget to imagine 3 cylinders stacked on each other and how little of the cell surface will experience meaningful cooling airflow.

Less surface area.
Horrible airflow characteristics.
Thick section thickness.

None of those add to better cooling.

 

It seems to me the OP is pretty straightforward about what he is doing.

Offering a different pack option with no warranty for folks.
Basically he's saying, "Here is what I've done, and it's working. If anyone else wants to do it too, I will sell you the components."

It ain't the cheapest option out there, but so what?
Don't like it? Don't buy it.
Or buy it, and report back here. Good or bad.

He took an idea an improved on what was there.

New batteries are expensive. Look around even on sites like alibaba, etc.

Trying to provide just about any warranty on a battery product from China can be an exercise in futility.
Since there isn't years of data on the product, the OP is being pretty transparent about that.

 

Do you mind sharing your credentials?

You have shared a number of statements that you claim are facts. You are equally responsible to put up or shut up.

If you are at all interested in but one opinion, you are coming across as a raving loony with a big chip on his shoulder.

A lone warrior swinging his scythe through the poppy field, if you will.

I'm all for reasoned discussion and debate, but if this kind of ranting is the best you can do would you please stop?

If you wouldn't mind just taking a chill pill, a deep breath and pause for a bit and really think about your approach.

Thank you.

 

Your comment concerning dealings with China are telling about quality and integrity of Chinese products.

The OP isn't being transparent. He's making many marketing based claims of superiority without any substantiation where existing reliability data conflicts with his statements. These are dismissed with a wave of the hand - "trust me, look at my post count".

Is this a case of a high post-counter defending another? It's clear that you skimmed my post. The vast majority of points that I made are either self-evident, or they are supported by readily available or provided data. Please re-read with an emphasis on objectivity and comprehension.

1. Admitted partial speculation, but you can find accounts of people that have to wait a an extra day or two because the dealer doesn't have a pack in stock. Draw your own conclusion.
2. Readily evident from a wealth of forum data. Single subpack replacement frequently restores function to a pack. Voltage readings on failed subpacks are typically in the vicinity of 1.2V lower than the rest - single cell failure.
3. Supported by provided reliability data
4. Self-evident fact.
5. "High" is optimistic. "Higher" is more appropriate. Computations supplied in this thread.
6. Data provided.
7. Self-evident based on visual examination and understanding of the airflow in the pack.
8. NASA link provided.
9. Supported by NASA link provided.
10. Conclusion based on data supplied. If airflow around a single cylinder is horrible, it's a logical conclusion that multiple cylinders stacked in the flow will not improve the flow. In fact, the upstream cells actually BLOCK a large portion of the downstream cylinders from air flow.
11. Fact. Measurements provided.
12. Web research yields supporting data.
13. Personally observed data compared between the mentioned Torque Pro readings on my Prius and the OBDIIC&C readings on my Insight.
14. Physical fact supported by OP's pictures. Airflow comments supported by linked NASA data.
15. Self-evident fact.
16. Conclusion based on previously supplied facts and supporting data.
17. Self-evident facts and/or facts/conclusions based on supplied reliability data.

Maybe I do come across as a loon. It's no more loony than the multiple unsubstantiated claims of superiority that is countered by all available data.

There is no objective evidence that this configuration is more reliable than anything currently on the road. All existing data supports the opposite.

If you pull out all of the BS speculative/unsubstantiated marketing claims, I would actually have no problem with this. It's an option. Take it or leave it, but multiple factual inaccuracies and claims of superiority made solely for increasing the fatness of the OP's wallet are bogus.

My hope is that a reader reads my posts after they read the marketing material and can then make an informed choice.

So loony.