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TinyBrain
(@tinybrain)
Active Member

https://s7d9.scene7.com/is/image/Audiusastaging/battery-liquidcooling?wid=1331&fit=constrain

e-tron has the following specs

300kW system power
432 pouch cells Li-Ion = 95kWh capacity

e-motors
front 125kW
rear 140kW

batteries
36 cell modules with each 12 cells and 60Ah per cell

system voltage
396V high voltage

these are the online specs. But I struggle to understand the math, pls help.

12 cells x 60Ah/cell = 720Ah, right?
36 modules x 720Ah = 25920Ah, right?

36 modules x 12 cells/module = 432 cells, right?

25920Ah x 396V = 10264320 Wh = 10264.32kWh, right?

how can they say 95kWh of capacity of the e-tron? I kindly ask for help.

4 fun see this

https://cdn.motor1.com/images/mgl/rgZbO/s1/audi-e-tron-prototype-at-pikes-peak.jpg

Quote
Posted : 04/05/2019 9:12 am
C.R.S.
(@c-r-s)
Active Member

The background intel on middle-school physics must be guarded by strong internal policy in your organization, segregated from the SoC forensics team.
Seriously, how ridiculous is that game supposed to get?

ReplyQuote
Posted : 04/05/2019 1:26 pm
TinyBrain
(@tinybrain)
Active Member

There is encrypted communication in the e-tron. To understand a project I start on basics.

ReplyQuote
Posted : 05/05/2019 5:41 am
athulin
(@athulin)
Community Legend

There is encrypted communication in the e-tron. To understand a project I start on basics.

Which very probably is the right place to start.

But are such studies 'forensic'?

No. They are part and parcel of the expertise a 'e-tron forensic expert' needs to have. But they're not 'computer and digital forensics'. Just as the study of how a Lenovo laptop is designed from scratch is not 'forensic' but rather part of PC architecture or perhaps IT or Electronic Architecture in general, although knowledge of exactly how laptop power supply and battery power works may be important to settle question what it really means when the suspect claims to have turned his particular laptop off.

Perhaps I should say that I interpret the word 'forensics' as 'being closely related to issues that legal processes need to have expert information about', and 'computer forensics' to relate closely to computers. It's not a synonym to 'hacking', in any sense of the word. General fact finding and collection, as well as research of any topic, is not forensics (to me) unless there is a clear connection with legal question.

Thus, my immediate impression is that this is rather off topic, at least for this particular forum 'General Discussion'.

Once the level of computer-based information contain in a e-tron, and questions about access and interpretation are formulated, I would judge it to be on-topic again. But then we're out of 'fundamental studies' and have reached a more advanced level, just as 'forensic pathology' does not concern itself with general medical question, except as they relate to a particular pathological problem, even though the pathologist must have that general knowledge.

As interest in car forensics does not seem to warrant a dedicated forum (though that is clearly a question for the admins), my suggestion would be to ping this group for interest in this and similar matter, but generally keep further discussion in the Off-Topic forum.

The general 'tilt?' feeling of other responses may suggest that I'm not alone in thinking so.

ReplyQuote
Posted : 05/05/2019 7:59 am
armresl
(@armresl)
Senior Member

So he would be in General, Mobile, and then Off Topic.

As interest in car forensics does not seem to warrant a dedicated forum (though that is clearly a question for the admins), my suggestion would be to ping this group for interest in this and similar matter, but generally keep further discussion in the Off-Topic forum.

The general 'tilt?' feeling of other responses may suggest that I'm not alone in thinking so.

ReplyQuote
Posted : 05/05/2019 10:14 am
jaclaz
(@jaclaz)
Community Legend

So, once said that it is an Off Topic, the issue is that to take a "basic" challenge you also need some "basic" knowledge[1] AND risk when the info is not enough or "as is" doesn't make sense to take some (common sense) assumptions.

Besides, it makes NO SENSE whatsoever to post a link to an image and NOT one to the technical specifications that are mentioned, and that likely you got from here
https://insideevs.com/news/340435/audi-e-tron-under-the-skin-battery-pack-motors-amp-more/

Here is the liquid-cooled battery pack - 95 kWh. It consists of 36 modules, 12 cells each - total 432 cells. The cells are pouch type, 60 Ah, supplied by LG Chem. The nominal voltage of the system is 396 V.

The voltage of 396 Volts is the voltage level of the motor (circuit) and it is "nominal".

A single cell is (normally) around 3.5-3.9 Volts, let's try with 3.6 V

If they are connected in series, that would make a module with
12*3.6=43.2 Volts (and still 60Ah)

Now, let us image that modules are grouped in 4 "rows", each one made of 9 cells in series
9*43.2= 388.8 V (and still 60Ah)

And now, let's assume that the four "rows" above are assembled in parallel
4*60Ah=240 Ah (and still 388.8 V)

The result is a system that has a nominal voltage level of 388.8 V (if you use 3.665 volts the above calculation will come out almost exactly 396 V) and has 240 Ah of capacity.

Now, 396V*240Ah=95040 Wh = 95 kWh

Viceversa, you could take the 95 kWh declared, i.e. 95000 Wh and divide them by the nominal voltage
95000/396=239.89 Ah

Then 240 Ah/60 Ah=4 => definitely there are four "groups" (or "rows") of modules
and
396/12/3.5=9.42 =>9
396/12/3.6=9.16 =>9
396/12/3.7=8.91 =>9
396/12/3.8=8.68 =>9
396/12/3.9=8.46 =>8

so, let's try with 9 modules per group
4 groups * 9 modules * 12 cells= 432

It seems fine to me.

jaclaz

[1] In this case, besides knowing that V*A=W, you need to know that connecting batteries together in series sums up V (and NOT A) while connecting them in parallel sums up A (and NOT V)

ReplyQuote
Posted : 15/05/2019 6:13 pm
TinyBrain
(@tinybrain)
Active Member

toda

ReplyQuote
Posted : 16/05/2019 8:06 am
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