What is the nominal battery voltage for the Tesla Model 3 batt pack options?

[A2be]

Are there any public specifications, from Tesla or from the after-market technicians who've examined Model 3's in the wild, that specify the nominal Li-ion battery voltage for each of the various Model 3 configurations?

I got the following battery energy storage specs from @Zoomit earlier today. I would love to fill in at least the three blanks on nominal battety pack voltage.


Model 3 Long Range : 75 kWh Pack voltage = ___V
Model 3 Mid Range : 62 kWh (discontinued)
Model 3 Std Range+ : 52 kWh Pack voltage = ___V
Model 3 Std Range : 48 kWh (software limited SR+ pack) Pack voltage = ___V


(Rationale: I'm building a comparison matrix on my Model 3 with an EV conversion I built back in 1980, built out of a junkyard Mazda RX-3 internal combustion engine (ICE) vehicle.)

 

[Zoomit]

All the Model 3's use a 96s battery configuration. The Li-ion chemistry they use has a nominal voltage right around 3.65v, which gives a 350v nominal voltage. Here's a reference from Tesla that includes this: https://iaspub.epa.gov/otaqpub/display_file.jsp?docid=46585&flag=1

See also: What's the battery voltage from 0% to 100%?

 

[A2be]

Does that mean all of the battery strings in all Model 3 batt pack always have 96-batteries in a serial string?

... and that therefore, the various batt packs of diverse kWh energy capacity are merely built up of more or fewer of these 96-battery "modules"?

That would be super cool to find somewhere where that is all described or laid out.

 

[Ampster]

Do you mean to say more or less number of parallel cells in each module? 96 modules is the same for each pack.

 

[Zoomit]

Does that mean all of the battery strings in all Model 3 batt pack always have 96-batteries in a serial string?

... and that therefore, the various batt packs of diverse kWh energy capacity are merely built up of more or fewer of these 96-battery "modules"?

That would be super cool to find somewhere where that is all described or laid out.

Do you mean to say more or less number of parallel cells in each module? 96 modules is the same for each pack.

The Model 3 battery pack contains 4 modules. Within each module the individual cells are arranged in bricks. Those bricks are not separable but just represent the electrical groups of the cells.

Long Range:
2 modules have 23 bricks in series and 2 have 25 bricks in series. Each LR brick contains 46 cells in parallel. 4416 total cells
2x 23s46p + 2x 25s46p = 96s46p

Standard Range:
All 4 modules have 24 bricks. Each SR brick contains 31 cells. 2975 total cells
4x 24s31p = 96s31p

New Tesla Model 3 Battery Details, Images & Video Released
Tesla Model 3: Exclusive first look at Tesla’s new battery pack architecture
SR & SR+ Battery Questions & Thoughts

Here's my guess at the SR module layout.

 

[A2be]

The Model 3 battery pack contains 4 modules. Within each module the individual cells are arranged in bricks. Those bricks are not separable but just represent the electrical groups of the cells.

Long Range:
2 modules have 23 bricks in series and 2 have 25 bricks in series. Each LR brick contains 46 cells in parallel. 4416 total cells
2x 23s46p + 2x 25s46p = 96s46p

Standard Range:
All 4 modules have 24 bricks. Each SR brick contains 31 cells. 2975 total cells
4x 24s31p = 96s31p

New Tesla Model 3 Battery Details, Images & Video Released
Tesla Model 3: Exclusive first look at Tesla’s new battery pack architecture
SR & SR+ Battery Questions & Thoughts

Here's my guess at the SR module layout.

That is very helpful Zoomit.

Is there a good short definition of "s" and of "p"?

I don't see a legend anywhere and this is just a bit Tesla inside-baseball esoteric.

 

[Zoomit]

s vs p? just battery nomenclature for in series vs in parallel.

 

[A2be]

s vs p? just battery nomenclature for in series vs in parallel.

That is all super helpful @Zoomit.

I built an EV conversion in 1980, from an old junkyard Mazda RX-3. Sold it to a guy in Wisconsin in 2003. I decided to tell a bit of its history and comparison to my base model Tesla Model 3, writing a few tweets on Twitter most days since the day I got my Tesla a month ago.

THERE.IS.NO.COMPARISON!

I'm done with all the stories, and now just plan to put up a comparison matrix on a few key metrics (power, energy, batt characteristics, etc.). If all goes well, I'll get that finished up and post it on Twitter tomorrow.

 

[timk225]

350 volts. Tree fiddy.

 

[darth_vad3r]

The Model 3 battery pack contains 4 modules. Within each module the individual cells are arranged in bricks. Those bricks are not separable but just represent the electrical groups of the cells.

Long Range:
2 modules have 23 bricks in series and 2 have 25 bricks in series. Each LR brick contains 46 cells in parallel. 4416 total cells
2x 23s46p + 2x 25s46p = 96s46p

Standard Range:
All 4 modules have 24 bricks. Each SR brick contains 31 cells. 2975 total cells
4x 24s31p = 96s31p

New Tesla Model 3 Battery Details, Images & Video Released
Tesla Model 3: Exclusive first look at Tesla’s new battery pack architecture
SR & SR+ Battery Questions & Thoughts

Here's my guess at the SR module layout.

Shouldn’t the ratio of the capacity of the LR vs SR+ be 46:31?

E.g. 74:49.9, or 74.2:50, or 77.2:52?

75kWh and 52kWh referenced in OP (sourcing you?) doesn’t match with the ratio of the cells in parallel being 46:31?

Or is there a magical “spare” cell in each brick that can sub in if another fails?

That would make the ratio 45:30. I don’t even know if that’s something that’s possible with the way the bricks are wired, I think they don’t have that fine control over cells within a brick, do they? Just the thermal fuse style fine wire attachments that can permanently take a cell out of a brick if it goes haywire. Can they otherwise control cells individually??

 

[Zoomit]

Shouldn’t the ratio of the capacity of the LR vs SR+ be 46:31?

E.g. 74:49.9, or 74.2:50, or 77.2:52?

75kWh and 52kWh referenced in OP (sourcing you?) doesn’t match with the ratio of the cells in parallel being 46:31?

Or is there a magical “spare” cell in each brick that can sub in if another fails?

That would make the ratio 45:30. I don’t even know if that’s something that’s possible with the way the bricks are wired, I think they don’t have that fine control over cells within a brick, do they? Just the thermal fuse style fine wire attachments that can permanently take a cell out of a brick if it goes haywire. Can they otherwise control cells individually??

The BMS controls and balances only at the brick level, as far as I understand.

But to address your first question, the capacities are likely ratioed by 46:31 as you suggest. Unless the engineers choose to create, say a 2 kWh buffer at the bottom, not a 2% buffer. (just throwing out numbers)

There's considerable debate about what the actual usable capacities are. You can read some perspectives in this thread:
Tesla's 85 kWh rating needs an asterisk (up to 81 kWh, with up to ~77 kWh usable)

One camp is based on personal testing, another camp is based on the Tesla documents submitted to the EPA.

Also, I learned the SR pack is configured a little differently. Here's a new graphic:

 

[A2be]

Hey @Zoomit.

I finished getting the data I wanted to collect for that comparison matrix, and posted this two-tweet thread on Twitter today, to end the 30 days of stories I've been telling about my first EV (named Rex) that I built from a junkyard Mazda RX-3 in 1980, and drove from 1980-2003,

and also some about #my2ndEV is a #TeslaModel3

Thought you might be a bit interested. I think you'll enjoy the table, but especially the second tweet with some summaries of how far EV technology has advanced in 40 years; and Tesla has been seriously advancing it!

 

[Zoomit]

Hey @Zoomit.

I finished getting the data I wanted to collect for that comparison matrix, and posted this two-tweet thread on Twitter today, to end the 30 days of stories I've been telling about my first EV (named Rex) that I built from a junkyard Mazda RX-3 in 1980, and drove from 1980-2003,

and also some about #my2ndEV is a #TeslaModel3

Thought you might be a bit interested. I think you'll enjoy the table, but especially the second tweet with some summaries of how far EV technology has advanced in 40 years; and Tesla has been seriously advancing it!

Wow, that RX-3 was impressive, for what it was. Genuinely home-grown. The Model 3 must be like the Starship Enterprise in comparison.

 

[A2be]

Wow, that RX-3 was impressive, for what it was. Genuinely home-grown. The Model 3 must be like the Starship Enterprise in comparison.

Yeah, very homegrown. here's the first tweet in the series when I kicked it off on the day I received my Model 3, here's the torque/current/speed and top-speed theory day, and here's when I had fun identifying my EV conversion as "ugly and slow and boring, like a golf cart" which is exactly what Elon said in a 2014 60-Minutes interview that I linked to.

 

[coug77]

Would be cool if you share more details about your conversion just for the
history.