What 282 kWh CATL LFP look like

[yabert]

I was really lucky and was able to bought new old stock of four 70.5 kWh CATL batteries built to be use on electric truck (class 6-7... you know, big truck, but not semi).
I didn't really know what was inside at the time of purchase except they are 70.5 kWh, 96S (309V nominal) and 228Ah cells build in 2020. My main goal was to have one 24V or 48V 70.5 kWh battery in our house and sell the other 211 kWh.
I received the 4 batteries few days ago and I uncrated one to see how it build.
I measure the voltage between one terminal and the disconnected MSD, 315V, good.
I removed the lid and fu*k, the cells terminals are welds and not bolted
Few seconds later, aaaaaaah! they are weld in pack of 16S, nice ?
So 6 packs of 16S 228Ah with 6 BMS ''slave'' (no fets, no contactors to cut power).
Awesome, I will be able to sell many 48V 11.7 kWh 170 lbs batteries at good price... well, not really.
As battery designer myself, I was intrigued by the manner those prismatic cells was hold on the big aluminum chill plate. Kind of strapped support? Tie down with bolts?
No, they are glue/bond on the chill plate and look to be impossible to separate except by cutting the chill plate.

Well, it seem like I could fairly easily cut the chill plate in two and have 35 kWh batteries, but it almost certainly the smallest battery I can do with this. The main problem is evidently the weight as 35 kWh is 450 lbs. Not so easy to move around.
There is also the size of 70 kWh, 2050×640×240mm (81 x 25 x 9.5''). Not really small.

Anyhow, those batteries seem really well build with compression straps and casted end plates, rubicond flexible PCB to reach BMS, wire bond fused between terminals and PCB, heat pads at each side of the cells, huge busbars, everything look good quality.

 

[yabert]

There is two connectors marked ''LV output'' on each 70 kWh battery to control external relays.
I used translate to know what is wrote on the stickers of those wires coming from BMS's and exit the battery via connectors. I still don't know if those pink/purple wires are CAN signals.
And why 12P?
Any thoughts?

 

[redalertdt]

Cool, what are you planning to sell them for?

 

[yabert]

Cool, what are you planning to sell them for?

what... not sure to understand. Do you mean:
-When: In few weeks. I have to complete the set up to move 1000 lbs around in the garage.
-Why: Because I really don't need 282 kWh of storage in our small house with only 1500W of solar install. 70.5 kWh in the house + 64 kWh on wheels in the driveway is way enough.

 

[oglark]

what... not sure to understand. Do you mean:
-When: In few weeks. I have to complete the set up to move 1000 lbs around in the garage.
-Why: Because I really don't need 282 kWh of storage in our small house with only 1500W of solar install. 70.5 kWh in the house + 64 kWh on wheels in the driveway is way enough.

I think he is asking how much money you are looking to sell the half of the battery you are not going to keep.

I am more interested in how you found them. One of my long-term projects on my bucket list is an EV conversion and I am interested in how you sourced that battery.

 

[740GLE]

Also anyone buying EV packs better assume welded connections, I can’t fathom any EV that would have bolted connections common found in DIY packs.

Just a hunch

 

[yabert]

Also anyone buying EV packs better assume welded connections

You are right. There is the Ford Fusion energi battery who is build from cells with bolted connection, but except that, most are weld.
The thing is not every welded connections are created equal.
From Nissan Leaf 2S modules with useful M4 nut center tap, to the 6S modules of an Ioniq 5, or a 10S modules of a Chevy Bolt without nuts compare to a Kia Soul EV 10S modules with M5 bolts at each cells, passing by the 23S and 25S modules of a Tesla 3, there is a lot of different welded connections.
When it's time to rearrange a 360V battery to build a 48V battery, the job can be fairly easy up to almost impossible.

And to add, considering those CATL battery are not typical EV battery, used 228ah prismatic cells and are use for heavy truck, I wouldn't have been surprised if all the connections was bolted.

 

[SolaroSsaurius]

I was really lucky and was able to bought new old stock of four 70.5 kWh CATL batteries built to be use on electric truck (class 6-7... you know, big truck, but not semi).
I didn't really know what was inside at the time of purchase except they are 70.5 kWh, 96S (309V nominal) and 228Ah cells build in 2020. My main goal was to have one 24V or 48V 70.5 kWh battery in our house and sell the other 211 kWh.
I received the 4 batteries few days ago and I uncrated one to see how it build.
I measure the voltage between one terminal and the disconnected MSD, 315V, good.
I removed the lid and fu*k, the cells terminals are welds and not bolted
Few seconds later, aaaaaaah! they are weld in pack of 16S, nice ?
So 6 packs of 16S 228Ah with 6 BMS ''slave'' (no fets, no contactors to cut power).
Awesome, I will be able to sell many 48V 11.7 kWh 170 lbs batteries at good price... well, not really.
As battery designer myself, I was intrigued by the manner those prismatic cells was hold on the big aluminum chill plate. Kind of strapped support? Tie down with bolts?
No, they are glue/bond on the chill plate and look to be impossible to separate except by cutting the chill plate.

Well, it seem like I could fairly easily cut the chill plate in two and have 35 kWh batteries, but it almost certainly the smallest battery I can do with this. The main problem is evidently the weight as 35 kWh is 450 lbs. Not so easy to move around.
There is also the size of 70 kWh, 2050×640×240mm (81 x 25 x 9.5''). Not really small.

Anyhow, those batteries seem really well build with compression straps and casted end plates, rubicond flexible PCB to reach BMS, wire bond fused between terminals and PCB, heat pads at each side of the cells, huge busbars, everything look good quality.

Thanks for sharing!
What a beauty!!

 

[yabert]

What a beauty!!

Yes. It's really well build and I think it should give a good idea of how to build a DIY stationairy battery pack.
All the good procedures are there: Straps to compress cells, insulator at strategic places, solid end plates who can fix cells in place, plastic insulator between end plate and cell, heatpads, etc.

Simply forget the fused PCB for the BMS, the glue to fix the cells on the chill plate and the chill plate.

 

[chriscappuccio]

Are these meant for TEVVA trucks?

 

[SparkyJJO]

what... not sure to understand. Do you mean:
-When: In few weeks. I have to complete the set up to move 1000 lbs around in the garage.
-Why: Because I really don't need 282 kWh of storage in our small house with only 1500W of solar install. 70.5 kWh in the house + 64 kWh on wheels in the driveway is way enough.

SURE you do!

.... If I had that, I'd use it anyway. Just because.

Could get through an entire winter of not a lick of sunshine that way!

 

[yabert]

I think he is asking how much money you are looking to sell the half of the battery you are not going to keep.

I plan to sell 3/4 of the battery I have (211 kWh) for around 100$/kWh as is. A bit more if I work to build 48V battery.
Of course, I will not lose a second of time to manage shipping across the border and I expect to sell them at 100-150 km around Montreal. Local pickup.

I am more interested in how you found them. One of my long-term projects on my bucket list is an EV conversion and I am interested in how you sourced that battery.

I repeated this many time, but for an EV conversion you will need way more stuff than a good battery.
Motor, controller, charger, DC-DC, charge port, junction box, compatible CV shafts, brake booster, cluster, shifter, etc... all those parts are fairly available at the scrap yard
The easiest/cheapest way is to buy an entire crash EV.

 

[yabert]

Are these meant for TEVVA trucks?

No, but similar 6 wheels truck able to move 26 000 lbs around.

 

[yabert]

More pic of the wires bond pcb, BMS connectors and BMS.

 

[yabert]

How to separate this 70 kWh battery in six 11.7 kWh 48V battery?
Ideas are welcome.
I think about this since a week now.
The best would be to dissolve/remove the glue/epoxy who fix all the cells in place on the aluminum chill plate. I bet any product who can dissolve the glue will caused damages to the cells insulator (blue wrap). ?
Another idea should be to mill the chill plate in 6. The aluminum plate is roughly 1/2'' under the cells, so let say I cut 7/16'' and broke the 1/16'' left, that would work.
But how to do this with precision? The angle grinder is exclude, I don't have a 6x2 fts CNC...?
To add, the aluminum chill plate is an extrusion, so probably a soft 6063 alloy who is a pain to mill.
For information there is only 1/8'' between group of 16 cells.

Any idea is welcome.

 

[Skypower]

Perhaps a better way is to work with what you have and not cut it up.

 

[hwy17]

I would not want to remove the compression if it wasn't necessary for 16s. That's one of the coolest parts of these packs is the engineered compression.

 

[yabert]

Perhaps a better way is to work with what you have and not cut it up.

Yes and no. I have six 48V battery per 70 kWh. No way I will build a 96S battery. High voltage (309V) is a big downside and I'm far from interest to integrate a 96S BMS.
Another way, there is actually 6 BMS (one per 16S battery). This is the way to go, but of course I absolutely don't know how it work

The weight is the main point. 70 kWh is 1000 lbs and only 170 lbs for 11.7 kWh.
The second point is to put 16S battery in parallel. It's way easier if all battery have the main + on the same side and the main - on the other side (which is not the case right now).

 

[SparkyJJO]

Parallel BMS is easy enough.
Like I said earlier, if I had that I'd absolutely find a way to use it all!

 

[Skypower]

Well then, saw it. I’m assuming it’s the bottom plate that I see. If so, I’d flip it over and use a metal cutting circular saw with an aluminum blade. I’d clamp a guide bar (a flat strip of metal) for the saw’s depth plate to run against. Since it’s a soft aluminum you might consider several increasingly deeper passes and a use wax to minimize metal sticking. I have this little M18 metal cutting saw and it the most impressive hand tool I own. The only thing wrong with it is the job is over too soon (fun) and I didn’t have it years ago.