ElectricShitbox
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Slate is staying tight lipped on a lot of the specifics about the two battery options they'll be offering.
The information we do have is that the small battery is 52.7kwh and uses 5 modules, and the big battery is 84.3kwh and uses 8 modules. That works out to 10.54kwh per module for both packs. Now, they don't directly say that they're the same modules in both packs, so they could be different cells in a different number of series that adds up to the same capacity. However, they confirm in that video that they are NMC pouch cells from SK On assembled into "proven modules".
"400v architecture" is a loose term that can mean a range of voltages, but the most common architecture for NMC chemistry batteries is 96s. That's 96 "cells" in series, with each "cell" typically being several pouch or cylindrical cells in parallel. If you call "nominal voltage" 3.7v per cell, 96s is actually a nominal 355v, or peak of 398v (I'm going to use 4.15v/cell in these calculations, as that's the cutoff I've personally seen used in a few different vehicles, but many NMC cells are rated up to 4.25v/cell).
If Slate is using two different modules for their two different packs, the standard could use five 19s modules for a 95s system. The extended pack could use eight 12s modules for a 96s system. That would keep them very close in voltage (351v and 355v nominal). This is an example, they could both be higher or lower voltage, or even be fairly different voltages. There's really not enough information to know until they tell us something new.
However, the videos I've seen at least strongly suggest that they are using 5 or 8 of the SAME modules. If that's the case, then we can get some of an idea of the layout from external constraints.
So let's do a thought experiment on how that would work, starting from the information we DO know. SK On domestically produces cells/modules for Ford, VW, and Hyundai/Kia. Of those, only Ford has modules that are big enough to cram 10.54kwh of cells in. Hyundai/Kia uses a cell size that I think would work, but assembled into many smaller modules. The VW MEB platform uses a standardized VDA module, but they seem to be around 7kwh. The Mach E and F-150 both have larger modules that could fit the information we know, but the built in cooling plates of the F-150 modules make me think they're the most likely base for the Slate modules. All the other modules I've listed here are cooled from a plate that the modules sit on top of. Slate could have two different cooling plates, or the empty slots with no modules on the small pack could be just left like that, with some of the plate cooling nothing, but a module with it's own built in plate seems easier to use here. Also, for the F-150, they use the same module architecture with between 40 and 55 individual cells (here I'm talking about individual cells not cell groups) which will work for the number of cells needed to get the right voltage and capacity (back to that later). So that's my theory for what the "proven modules" are.
Voltage is the next constraint that can narrow down some possibilities for us. Slate has confirmed Tesla Supercharger access. All but 1 supercharger site (last I read it was still 1) are capped at 500v. Now eventually, they'll be updating to "V4" charging cabinets that are 1000v capable, but for now anything that operates at a higher voltage needs to do onboard voltage conversion. So we can assume for this thought experiment that there's a upper limit of 500v for both packs. The other part of this is that there's also a lower limit of 200v for most chargers, where they won't charge a pack that's under that limit. So we have a range of 200-500v that both packs have to fit in from dead to full.
With the two packs using 5 or 8 modules, there's no way to arrange them other than 5s or 8s. You can't add a 3 additional modules to a string of 5 in any way other than continuing the series, resulting in a different system voltage. I had previously guessed in another thread that the modules could be 14s, but after running through the rest of the numbers, they have to be 13s, 14s, or 15s. Five 12s modules would equal a total 60s system for a dead voltage of 192 (I'm using 3.2v/cell as the cutoff voltage, but this can vary). Eight 16s modules would give you a 128s system with a peak voltage of 531. So with that, you can see why we're limited to between 13 and 15 cell groups per module. Even though 13s modules would theoretically work, the voltage of the small pack would be very low, so I'm just going to narrow that down to 14s or 15s.
I've been trying to find more specifics on the cell capacities that SK On already makes, and it's tough to find, but their NCM9 cells seem to range from 55ah-87.5ah, with several falling in the 60-70ah range. This size range would work for each cell group being 3 pouch cells in parallel, which would fit into the F-150 module with a 14s being 42 total cells and 15s being 45 (the F-150 had 4p10s and 5p11s modules with 40 and 55 total cells, so similar physical size). To end up with a 10.54kwh module, it would be 3 cells with a capacity of 68ah each in parallel times 14 cell groups in series, or 3 cells with a capacity of 63ah each in parallel times 15 cell groups.
So with all that, you basically end up with two possibilities.
If the modules are 14s, the standard range battery would be a 70s system with a voltage range of 224-290, and the extended range battery would be a 112s system with a voltage range of 358-464.
If the modules are 15s, the standard range battery would be a 75s system with a voltage range of 240-311, and the extended range battery would be a 120s system with a voltage range of 384-498.
Or I'm entirely wrong, and they sourced two different module layouts with the same capacity, haha. More info, Slate!
The information we do have is that the small battery is 52.7kwh and uses 5 modules, and the big battery is 84.3kwh and uses 8 modules. That works out to 10.54kwh per module for both packs. Now, they don't directly say that they're the same modules in both packs, so they could be different cells in a different number of series that adds up to the same capacity. However, they confirm in that video that they are NMC pouch cells from SK On assembled into "proven modules".
"400v architecture" is a loose term that can mean a range of voltages, but the most common architecture for NMC chemistry batteries is 96s. That's 96 "cells" in series, with each "cell" typically being several pouch or cylindrical cells in parallel. If you call "nominal voltage" 3.7v per cell, 96s is actually a nominal 355v, or peak of 398v (I'm going to use 4.15v/cell in these calculations, as that's the cutoff I've personally seen used in a few different vehicles, but many NMC cells are rated up to 4.25v/cell).
If Slate is using two different modules for their two different packs, the standard could use five 19s modules for a 95s system. The extended pack could use eight 12s modules for a 96s system. That would keep them very close in voltage (351v and 355v nominal). This is an example, they could both be higher or lower voltage, or even be fairly different voltages. There's really not enough information to know until they tell us something new.
However, the videos I've seen at least strongly suggest that they are using 5 or 8 of the SAME modules. If that's the case, then we can get some of an idea of the layout from external constraints.
So let's do a thought experiment on how that would work, starting from the information we DO know. SK On domestically produces cells/modules for Ford, VW, and Hyundai/Kia. Of those, only Ford has modules that are big enough to cram 10.54kwh of cells in. Hyundai/Kia uses a cell size that I think would work, but assembled into many smaller modules. The VW MEB platform uses a standardized VDA module, but they seem to be around 7kwh. The Mach E and F-150 both have larger modules that could fit the information we know, but the built in cooling plates of the F-150 modules make me think they're the most likely base for the Slate modules. All the other modules I've listed here are cooled from a plate that the modules sit on top of. Slate could have two different cooling plates, or the empty slots with no modules on the small pack could be just left like that, with some of the plate cooling nothing, but a module with it's own built in plate seems easier to use here. Also, for the F-150, they use the same module architecture with between 40 and 55 individual cells (here I'm talking about individual cells not cell groups) which will work for the number of cells needed to get the right voltage and capacity (back to that later). So that's my theory for what the "proven modules" are.
Voltage is the next constraint that can narrow down some possibilities for us. Slate has confirmed Tesla Supercharger access. All but 1 supercharger site (last I read it was still 1) are capped at 500v. Now eventually, they'll be updating to "V4" charging cabinets that are 1000v capable, but for now anything that operates at a higher voltage needs to do onboard voltage conversion. So we can assume for this thought experiment that there's a upper limit of 500v for both packs. The other part of this is that there's also a lower limit of 200v for most chargers, where they won't charge a pack that's under that limit. So we have a range of 200-500v that both packs have to fit in from dead to full.
With the two packs using 5 or 8 modules, there's no way to arrange them other than 5s or 8s. You can't add a 3 additional modules to a string of 5 in any way other than continuing the series, resulting in a different system voltage. I had previously guessed in another thread that the modules could be 14s, but after running through the rest of the numbers, they have to be 13s, 14s, or 15s. Five 12s modules would equal a total 60s system for a dead voltage of 192 (I'm using 3.2v/cell as the cutoff voltage, but this can vary). Eight 16s modules would give you a 128s system with a peak voltage of 531. So with that, you can see why we're limited to between 13 and 15 cell groups per module. Even though 13s modules would theoretically work, the voltage of the small pack would be very low, so I'm just going to narrow that down to 14s or 15s.
I've been trying to find more specifics on the cell capacities that SK On already makes, and it's tough to find, but their NCM9 cells seem to range from 55ah-87.5ah, with several falling in the 60-70ah range. This size range would work for each cell group being 3 pouch cells in parallel, which would fit into the F-150 module with a 14s being 42 total cells and 15s being 45 (the F-150 had 4p10s and 5p11s modules with 40 and 55 total cells, so similar physical size). To end up with a 10.54kwh module, it would be 3 cells with a capacity of 68ah each in parallel times 14 cell groups in series, or 3 cells with a capacity of 63ah each in parallel times 15 cell groups.
So with all that, you basically end up with two possibilities.
If the modules are 14s, the standard range battery would be a 70s system with a voltage range of 224-290, and the extended range battery would be a 112s system with a voltage range of 358-464.
If the modules are 15s, the standard range battery would be a 75s system with a voltage range of 240-311, and the extended range battery would be a 120s system with a voltage range of 384-498.
Or I'm entirely wrong, and they sourced two different module layouts with the same capacity, haha. More info, Slate!
