@Skyart 180mm x 115mm x 45mm
Neither, they are prismatic cells.
These particular cells seem to have minimal compression in their package. There’s actually about a 5mm gap between each cell in these modules, and there’s a small bit of what looks like dense foam compressing the sides of the cells to each other and keeping them from rattling around.
Price drop on all battery modules 
Just added, check it out!
These were another case where it was hard to find good, verifiable sources for specs. There are lots of other listings online that list all kinds of different specs for these modules, but I was not able to find any good sources for anyone’s claims. If anyone knows anything they can point me to, I would be thrill to hear it!
In the mean time, this is what I chose to list for the specs I couldn’t find (underlined in red):
What do yall think of that method for rating these modules?
For anyone who should be wanting to buy something like this, that mathematical explanation of the ratings seems sound to me.
This phrase hit me right in the feels.
I cant count how many times I have been asked a… how do I put this nicely… “uneducated” question from a would-be-customer and I just want to reply “I dont think it’s safe for you to buy this battery.” 
I’m glad to hear that! My main conern with what I listed there was where the data was sourced. Basically, I dont know if using the car’s specs to derive the module’s specs is the best way to go about it.
I would guess that the car’s specs are going to be well inside the maximum specs for the cells/modules, but I could be totally wrong about that.
im pretty sure most car don’t use amps anywhere close to stressing the battery cells inside, even if they have cooling system in place to keep the cells happy. they have all the real estate to put in however many cells they want inside. it would be a liability issue if their car system stress the cells too much to a point where they either degrade to impact range in short period, or worse, going kaboom when parked or being driven.
That’s a great point, and it’s exactly what I suspect the truth to be.
But I dont know for sure, and I get a bit stressed trying to avoid putting bad info out into the world haha. There is already so much “info” out there on product pages, forums, “news” articles, etc. etc. etc., that’s completely un-sourced, un-verifiable, and contradictory to other sources. And then when someone puts that bad info out, it spreads and gets used as a citation for someone else’s bad info.
I want to make sure everything I put out is verifiable, so others can check my work and come to the same conclusion rather than just having to take mt word for it, which seems to be the norm in the battery module resale industry.
this is hard to do
unless car oem hand out their battery pack info, or else no one is supposed to know what’s inside, how its built and what amps their are rated for. any test report generated by the public needs to be done in their own workshop / home / garage whatnot, im not trying to shoot down peple who do these test, in fact, i love them, they are doing great work for a lot of community, but how scientific the test is done / how trustworthy is such individual also needs to be taken into account for if such publication is made.
for oem battery pack resale industry, i would only expect official specs list that oem stated, spec datasheet sure would help, but source needed. anything else is either “unofficial / tested by general public” and has to be mentioned in red bold or something that potential customer is aware of.
sorry for wall of text
Just listed these CATL modules
I never was able to find out what car these came out of, but I was able to find enough info about the cells/modules after a lot of digging to be confident in the specs listed. The capacity on these are huge for their size!
Two things on the mfr rating:
First basic-ish one, have you checked that this is used in a “1P” configuration? If there are multiples of these packs paralleled up, you may need to divide the current for both charging and discharging by 2/3/whatever. Potentially easy to find out, you might already have done it
Second is maybe nitpicking; the manufacturer’s rating for peak output power might assume full almost full charge, so the peak output current would be a bit lower. I don’t have a source that this happens though, and it does sort of go against good and useful naming practices, but it’s a very easy technical point to defend if they got called out and it’s a nice marketing tool so the cynicism is getting to me
The explanation and way it’s presented is good and having the logic laid out is great because if I was buying it I’d be able to verify or recalculate with my own assumptions (I could get max current assuming full charge, or estimate available energy in a 90%-10% discharge based on standard curves, or that kind of thing)
Yep! Nearly every EV battery I have researched is a ##s1p configuration, using thiccboi prismatic cells. Tesla is one of the few who do things differently, and even they have started to use prismatic cells (in the Model 3 being sold to the Chinese market, specifically).
Yeah this is something that I definitely considered when deciding to use that spec. Almost all of the specs that manufacturers release about their EVs and batteries and whatnot (which isnt much) are based on nominal SoC, so I used the nominal voltage for my calculations.
I agree that it’s concerning to use those numbers and assume that I know what the manufacturers meant by them, so that’s why I showed my work in case someone else wants to check my math and come to a different conclusion using information I was not able to find 
We have been selling out of these LTO battery modules as fast as we can break down the packs. One of the packs we broke down showed clear signs of water ingress at some point in the past.
While I dont want to recommend that anyone buys these modules (since they might be dangerous or useless depending on the damage, see product description for more info), if you want to get your hands on some of these cells to mess around with and you dont mind breaking down the module and cleaning/testing the cells… Well then this might be your cheapest option!
They are listed for $150, but the listing is set up to automatically accept offers of at least $130, just a tip. 
Man I always wondered how the “OBO” thing worked with big commercial sites on ebay, I thought it was just trying to game the filtering and make their listings come up in more people’s searches
Follow-up question:
But if it’s 1200W per cell then that’s like 25C discharge and a total ~29kW which is hilariously high
For some listings, this is definitely the case. On the back end, eBay encourages sellers to use stuff like OBO and insists that it leads to higher sales. For us, it allows us to put up flexible pricing which is good since a lot of the stuff we are selling is used/untested in addition to being really niche, so pinning down an exact value is difficult.
Per cell, according to this datasheet from Toshiba:
Unless I am reading it wrong? It’s very possible that I have either misunderstood the numbers in that datasheet, or done some math wrong when making my product description.
whoa partner those are some angry pixies in that cell. Yeah looks like you’re right about 1200W per cell, I guess it now makes sense that that’s a 10s limited power. I’m still mentally trying to get my head around what the config would have looked like in that car, because it had 20kWh total so that should be a craaazy amount of power. 36 bricks of 12 cells?
My guess is it’s a (12x12)S 3P setup. 12 bricks in series for 331V nominal, that’s in the right range of EVs (Leaf is a good benchmark at 350V). I guess it’s just been a while since I did the maths on how many modules you need to get to EV level capacity, even if you have big lads like this rather than 18650s. That gives you a theoretical burst battery power above half a megawatt though, which is truly wild
There were 18 of these double-modules in a pack, though I dont know exactly how they were connected regarding series and parallel.
Pretty much every EV pack I have looked into does not put modules in parallel, and the only time I have found modules which have cells in parallel are the Kia Niro EV and the Nissan Leaf packs, where their modules have a few cells in parallel. The modules are always connected in series, as far as I can tell.
That would be strange for the Fit-EV though, because if all 18 of these 24s modules were connected in series then there would be 432 cells in series, or a nominal voltage of 993.6V. That seems… a bit high
Yeah nearly all the EV batteries I have come across so far are right around 350V nominal, +/-10V. Seems to be something of an industry standard.
Speaking of the Kia Niro EV…
These modules are absolutely nuts. They weigh a ton, and the specs are crazy. If you want to build an electric go-kart or something, these could be great. Put two of the 10s in series and you have a 13kWh 20s battery. Put the two 9s in series and you’ve got a 12kWh 18s battery.
I dont recommend putting these modules in anything that you have to lift They are nearly 70lbs each. They actually come in the car bolted in pairs to a cooling plate, so I had to dead-lift 150lbs of battery just to get them off the floor and onto my workbench so I could break them down. I had to do that 5 times 
Sir, you need to buy an engine hoist, asap
