[Kevin Sharpe]

I've been stripping down some "Gen 2" Leaf Modules and thought I'd share the details because they are a lot easier to work with than the older "Sardine Can" design.

I'll start with some photo's and add more details over the next few days

 

[Kevin Sharpe]

Note that you can separate the outer aluminium 'skin' using simple tools, no need to cut anything. Separating the aluminium 'skin' from the insulator protecting the cell pouch takes some time because it has strong adhesive.

 

[Kevin Sharpe]

Not much weight in the skins and spacers...

 

[Kevin Sharpe]

Nissan no longer have modules that swap the positive/negative terminals around, but they do have some with additional mounting hardware (12 of the 48 modules in the battery). This hardware can be easily removed although it could be useful for improving battery rigidity...

 

[Caps18]

Pretty interesting. I have taken apart the first gen LEAF batteries and have all the pieces on the floor. I'm not removing the aluminum shell though.

 

[electro wrks]

It looks like to me the way the Al shells are bonded to the pouches, the shells may be important for heat transfer (both heating and cooling) in the battery pack. Do the adhesive patches look like they're made of a heat conducting material? If so, it may be something to think about if the pouches are used without the shells.

 

[Karter2]

Any test/performance data from these cells ?
Much change to the earlier type. .
Capacity ?
DCIR. .?
Discharge plots ?

PS:... Have you tried the drop of Isprop Alcohol trick, to separate the glue from the shells.

Oh, and thanks Kevin for posting these pics ...very interesting.

 

[Kevin Sharpe]

It looks like to me the way the Al shells are bonded to the pouches, the shells may be important for heat transfer (both heating and cooling) in the battery pack. Do the adhesive patches look like they're made of a heat conducting material?

The adhesive is not a heat conducting material and nor IMO is the 'plastic sheet' which I tested with a heat gun on one side and my hand on the other

It's clear from the pack design that no active cooling/heating of the modules is undertaken in the Leaf. I'll include temperature measurements when I test the cells.

 

[Kevin Sharpe]

Any test/performance data from these cells ?
Much change to the earlier type. .
Capacity ?
DCIR. .?
Discharge plots ?

We've produced no test data but I'm happy to run any tests that people would find useful. If you have a particular test setup or process let me have the details.

PS:... Have you tried the drop of Isprop Alcohol trick, to separate the glue from the shells.

Worked like a charm... thanks!

Oh, and thanks Kevin for posting these pics ...very interesting.

No problem... happy to share... were seeing ~3 Leaf's a day at auction in the UK so only a matter of time before these modules get really cheap

 

[Karter2]

Kevin,
I could not see from the previous photos, but what are the internal cell connections like ?
Welded ?, crimped ?, screw clamps ?. .??
Does it look feasible to re terminate a module to be 4S, 1P without major rework. .?

PS: I read the 2016 leaf will have a 30kWhr pack with modules of 4S,2p , presumably with 40Ahr cells?

http://insideevs.com/2016-nissan-leaf-107-miles/

As for the actual pack structure, the original 24 kWh battery is made up of 48 modules composed of 4 cells each, for a total of 192 cells. The new 30 kWh battery has double the cells per module (8), but still 192 cells in total. Nissan once again points to automotive-specific battery formats as a superior commodity.

 

[Kevin Sharpe]

Kevin,
I could not see from the previous photos, but what are the internal cell connections like ?
Welded ?, crimped ?, screw clamps ?. .??
Does it look feasible to re terminate a module to be 4S, 1P without major rework. .?

Here are some photos of the internal cell connections. I believe the tabs are cold welded to copper strips and IMO it does not look impossible to rewire the cells internally

 

[Yabert]

Ultrasonic welding. Nice!
Similar to the welding on chevy Volt cells and on some good electric motors.

Thanks to share Kevin.

 

[Kevin Sharpe]

PS: I read the 2016 leaf will have a 30kWhr pack with modules of 4S,2p , presumably with 40Ahr cells?

I believe the new "Gen 3" module is simply using two of the "Gen 2" style modules stacked together but with a higher capacity cell... I'm investigating a 4 module stack to save a little weight and thickness

One of the things I like about the Leaf battery's is that we already have three cell capacity's to choose from

 

[Kevin Sharpe]

No room for cooling/heating at the module level (and none included in the battery pack)...

 

[dcb]

Here are some photos of the internal cell connections. I believe the tabs are cold welded to copper strips and IMO it does not look impossible to rewire the cells internally

Thanks for posting, it looks fairly identical to the previous generation, with attendant headaches for reconfiguring for higher voltage.

 

[Kevin Sharpe]

final tally of easily removable parts and stripped down modules (note two different scales in use and while the KERN is calibrated the Salter is not )

 

[Karter2]

Here are some photos of the internal cell connections. I believe the tabs are cold welded to copper strips and IMO it does not look impossible to rewire the cells internally

Superb photos Kevin.
Yes , US welded,....or one Mutha of a crimp !
Thanks again.

 

[winzeracer]

Just modeled the Leaf cell. If anyone needs it let me know. Modeled in Solidworks 2015

 

[winzeracer]

I didn't model the guts. I doubt many would need that

 

[ekwok117]

Oh sweet! I would love the model. PM'd