Cathode Electrode Materials

[Anonymous]

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[Link]

I knew LiCo was more energy dense than LiFe, but I didn't know it was that much of a volumetric difference.

Looks like I'll have to at least try some high-rate packs on the "finished" BMX and see how it tackles half pipes. 8)

 

[dirty_d]

where can i get some lifepo4 for $25-$35 per kWh?

 

[Link]

LOL yeah. That too. I'm seeing prices more in line with $700kWh for the cheap stuff. :lol:

 

[Anonymous]

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[Link]

The chart confused me, what with listing the energy density of the thing. Plus batteries are pretty much defined by their cathode materials, so the the material and the battery itself have become sort of synonymous. :?

 

[Anonymous]

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[PJD]

I knew LiCo was more energy dense than LiFe, but I didn't know it was that much of a volumetric difference."

I sure did. LiFePO4 is bulky. My 40AH LiFePO4 pack fills the same volume in the battery boxes as the 40AH lead acid pack did. But it is a lot lighter, and with virtually no Peukerts effect, the actually-usable volumetric energy density is a lot higher.

 

[recumbent]

Great write-up, thanks for posting it for us.

"Thermal management of litium based cells is a critical element for achieving desired performance and calender life"

That's an important statement. They also said: 45-50 deg-C (about 120 deg-F) is the temperature limit.

Thanks again, I read almost all of it.

 

[Link]

I sure did. LiFePO4 is bulky. My 40AH LiFePO4 pack fills the same volume in the battery boxes as the 40AH lead acid pack did. But it is a lot lighter, and with virtually no Peukerts effect, the actually-usable volumetric energy density is a lot higher.

Is there a voltage difference between the packs? Because my 960Whr LiFe pack is volumetrically smaller and lighter than my 324Whr lead pack, and that's even before figuring in sag and Peukert. :?

 

[PJD]

"Is there a voltage difference between the packs?"

Nope. The 16 Thundersky cells's working voltage at 20 deg. C and a bit over a 2C load is exactly the same as freshly-charged lead acid - 48-49 volts. So, presumably if I discharged each pack at C/20, I'd get about 1920 WH out or each.