Battery pack cutaway

Interesting photo of the Battery pack.

neat!, do you have the dimensions?

Herm said:

neat!, do you have the dimensions?

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Surprised you hadn't seen it before. At the Drive Nissan Leaf events, they had one of these as part of the displays w/the lid propped open, instead of cut like that.

This looks computer-drawn, perhaps, instead of being a photo?

garygid said:

This looks computer-drawn, perhaps, instead of being a photo?

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How about this one?

http://www.flickr.com/photos/43375161@N00/4836467051/in/set-72157624599742550/

garygid said:

This looks computer-drawn, perhaps, instead of being a photo?

Click to expand...

Gary, it's very likely a photo, albeit a heavily photoshopped one. The header of that image contains the strings "Ducky" and "Adobe", which means that it was saved in Photoshop.

What are the actual dimensions of the "tuna can" modules? Did people finally decide on 24 or 27 Kw for the entire pack???

cwerdna said:

Surprised you hadn't seen it before. At the Drive Nissan Leaf events, they had one of these as part of the displays w/the lid propped open, instead of cut like that.

Click to expand...

Never made it to a Leaf driving event. Just ordered the car sight unseen.

Even at delivery the salesman wanted to show us the leaf before doing the paper work. We said no, lets just do the paper work first, then we will look at the Leaf.

TRONZ said:

What are the actual dimensions of the "tuna can" modules? Did people finally decide on 24 or 27 Kw for the entire pack???

Click to expand...

http://www.eco-aesc-lb.com/en/product.html

Cell type: Laminate type
Cathode material: LiMn2O4 with LiNiO2
Anode material: Graphite
Rated capacity (0.3C): 33.1 Ah
Average voltage: 3.8 V
Weight: 799 g
Dimensions
-Length: 290 mm
-Width: 216 mm
-Thickness: 7.1mm

Module
Number of cells: 4
Construction: 2 parallel, 2 series
Dimensions
Length: 303 mm
Width: 223 mm
Thickness: 35 mm
Weight: 3.8 kg


There are 48 modules total, which is 192 cells. If each cell is 125.78 watt-hours (3.8V * 33.1Ah) then the entire pack is 24652 watt-hours, or 24kWh nominal. That's the manufacturer's specs, so it's not really known if this includes in-service padding or if Nissan added more padding on top of anything these ratings may or may not include.
=Smidge=

Thank You!

Smidge204 said:

That's the manufacturer's specs, so it's not really known if this includes in-service padding or if Nissan added more padding on top of anything these ratings may or may not include.
=Smidge=

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Thank you for posting that!

In terms of the rated capacity, please have a look at the discharge curve. If you integrate the area below the blue line, you will get the amount of energy supplied by the battery during a moderate discharge. This area seems to be close to the rated capacity of 125Wh. It's not clear if the cell was charged to 4.1V, which corresponds to our 100% charge, or something higher. If the results found in studies on other lithium manganese cells are transferrable, then the cell maximum would be in fact at 4.17V, and anything above or below that voltage would yield less energy.

By the looks of it, the rated capacity does include both the padding on the top, i.e. the delta between 4.17 and 4.1V, and at the bottom, i.e. the delta between the end of turtle at 3.2V and cell minimum at 2.5V. Given this data, it's unlikely that the total pack capacity is much different from 24 kWh.

On a related note, 85% to 87% ratio between usable to rated capacity seems to be a common theme among the recently publicized EVs. This in turn would support the empirically determined 21 kWh of usable capacity.

Smidge204 said:

There are 48 modules total, which is 192 cells. If each cell is 125.78 watt-hours (3.8V * 33.1Ah) then the entire pack is 24652 watt-hours, or 24kWh nominal. That's the manufacturer's specs, so it's not really known if this includes in-service padding or if Nissan added more padding on top of anything these ratings may or may not include.
=Smidge=

Click to expand...

Cell manufacturers usually dont pad anything, but since AESC is partially owned by Nissan who knows?. We really wont know until someone buys a module and tests it* , testing equipment is widespread in the EV community.. I am really surprised that no real tests have surfaced yet and we will soon come up on the 1 year anniversary. Those modules must be under armed guard at the dealerships.

* So far all the "evidence" we have is circular reasoning, to my knowledge no one has even instrumented a Leaf to actually measure the energy flow.. something that anyone can do with cheap tools from Sears. Measuring the actual efficiency of the charger should be easy also.

Not to be canibalistic... but some one needs to total a LEAF so we can grab the drivetrain parts.

TRONZ said:

Not to be canibalistic... but some one needs to total a LEAF so we can grab the drivetrain parts.

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Even then it will probably be cheaper to just pony up the $600 Nissan wants for a single module.

We think that the SOC-Meter (F1.08) shows Battery Pack
voltage and current (and calculates power).