Lithium-manganese or LiFEPO4 for 72V, which is safer?

[4LivesPerGallon]

Hi, newbie "manganese" question re 18650 Lithium manganese for 72V 200lb 'cycle --- this a good idea? Said to be much cheaper than a Li-Fe pack.

The 18650's will be in 18650 "banks" that have HVC and LVC BMS, but not at a cell-level. So, what happens is an individual 18650 fails or shorts?

Asking for actual experiences. Thank you.

 

[dogman dan]

See Justins thread on battery potting experiments. Some video of a cell going into thermal runaway there.

 

[999zip999]

? What's the battery for ? What controller ? What sizr battery ah ?

 

[liveforphysics]

While it's true various cathode materials decompose at different temperatures, in practice it hardly matters because the SEI is the weak link to send them into runaway before the cathode starts liberating it's Oxygen.

Essentially, the safest cell is the cell designed to be safest and made with good QC practices. This could equally be a Cobalt Oxide cell or Iron Phosphate or Manganese Spinel or NCM or NCA.

To say one is safer than another from looking at the Cathode material composition alone is impossible.

 

[4LivesPerGallon]

While it's true various cathode materials decompose at different temperatures, in practice it hardly matters because the SEI is the weak link to send them into runaway before the cathode starts liberating it's Oxygen.

Essentially, the safest cell is the cell designed to be safest and made with good QC practices. This could equally be a Cobalt Oxide cell or Iron Phosphate or Manganese Spinel or NCM or NCA.

To say one is safer than another from looking at the Cathode material composition alone is impossible.

What is the SEI?

What do you think of the 5-way graphical representation of the different Lithium batteries? Based on Battery University, it appears that LIFEPO4 is the safest and longest-lived Lithium battery type.

http://batteryuniversity.com/learn/article/types_of_lithium_ion

 

[okashira]

While it's true various cathode materials decompose at different temperatures, in practice it hardly matters because the SEI is the weak link to send them into runaway before the cathode starts liberating it's Oxygen.

Essentially, the safest cell is the cell designed to be safest and made with good QC practices. This could equally be a Cobalt Oxide cell or Iron Phosphate or Manganese Spinel or NCM or NCA.

To say one is safer than another from looking at the Cathode material composition alone is impossible.

Exactly. I'd take a Panasonic made NCA over a Chinese LiFePO4 any day if safety mattered

 

[999zip999]

Quality. Quality. Start with a cell that can easily handle the load. High quality lifepo4 is expensive and are big and heavy. Long cycle life. I have 830 cycles and use at 90amps briefly. A123. Lot's of newer 18650 that can handle big loads and they are sealed in a can. Time will tell as we must wait 4-5 years. Hell my battery could last 4 more years or 8 years total. There a guy that has a 5 year cellman 48v 20ah lifepo4 A123.