Chemistries

Lithium Iron Phosphate (LFP) vs. Lithium Nickel Manganese Cobalt Oxide (NMC) Chemistries

Green Cubes typically utilizes Lithium Iron Phosphate (LFP) Li-ion battery chemistry over Lithium Nickel Manganese Cobalt Oxide (NMC) or Lithium Cobalt Oxide (LCO) battery chemistry for several reasons.

The use of Phosphates in LFP batteries avoids concerns of cost and environmental contamination (i.e. entering the environment through improper disposal) of Cobalt from LCO batteries.

Cycle Life for LFP Batteries

Cycle Life for Typical LCO Batteries

LFP Batteries provide superior cycle life and Total Cost of Ownership (TCO) for the life of a mobile workstation, as profiled in the charts above.  LFP batteries deliver at least 2500 – 3000 full charge/discharge cycles before reaching 80% of original capacity.  Typical NMC batteries deliver 500 – 1000 full charge/discharge cycles before reaching 80% of original capacity.  This means that LFP batteries provide FOUR times more cycle life than typical LCO batteries.

Total Cost of Ownership for SLA, LCO and LFP Battery Chemistries

LFP Batteries provide superior total cost of ownership over Sealed Lead Acid (SLA) and NMC batteries. As an example, consider a mobile workstation with a typical 7 year lifespan.  Over this lifetime, the SLA battery would be replaced every 6 to 12 months, depending on the usage profile. An NMC/LCO battery with similar capacity will cost roughly twice as much as the SLA battery, but its cycle life of typically two years is double that of an SLA battery. The upfront cost is higher, but over the lifetime of the mobile workstation, the total cost is lower. With an LFP battery, the initial acquisition cost is about 3 to 4 times that of a SLA battery, but the cycle life will cover the entire life of the mobile workstation itself.  The LFP battery will almost certainly have a lower cost over the life of the mobile workstation.

Thermal Runaway Points for Li-ion Chemistries

LFP Batteries have an intrinsically safer cathode material than NMC/LCO batteries and do not decompose at higher temperatures. This means LFP batteries provide the best thermal and chemical stability, which results in superior safety over NMC/LCO batteries. As profiled in the charts above, a LFP battery will only enter a thermal runaway condition at 270 Celsius and release minimal energy during thermal runaway. A typical NMC/LCO battery can enter thermal runaway condition as low as 150 Celsius. All Li-ion batteries are safe, but LFP is the safest Li-ion battery chemistry available.

12V vs. 24V Power Options

Green Cubes offers both 12V and 24V power configurations for  mobile computing workstations. 

24V Power systems have advantages over 12V systems. Since 24V systems operate at a lower current rating (measured in Amps), they have less impedance drop and power loss (due to heat) through interconnect cables. Therefore, 24V power systems allow smaller, lighter weight cable sizes and put less stress on parts of the system such as battery cabling, fuses and terminals.

24V Inverters are slightly more efficient that 12V inverters when converting DC input power from the battery to 120 or 240 VAC output power. This means that a 24V system will deliver some extra run-time over a 12V system. Regardless of the battery voltage, both 12V and 24V solutions offer comparable run-time and performance to their users.