LFP Batteries

The LFP cells are known in the industry for highest quality standards,

this new system is just slightly more heavier and needs almost the same space as our light NCM cells.

But there is a difference.

  • Safe!
  • High energy and power density
  • Robustness and reliability
  • Some extra safety margin compered to NCM 
  • MED volume, MED weight (not really true for this one)
  • Long life
LFP CELLS


In comparison, these batteries are lighter with the LFP cells than the NCM batteries from most competitors..
safety points
  • When we start from scratch, we do extensive failure analyses before and during design stage
  • Our BMS is robust and proven, used in many industry and marine applications
  • We measure each single cell voltage and get alarms if one of the cells should get bad instant, even on a trend
  • 4/7 balancing as soon as the cells hit a certain target, this to avoid self-discharge and unneeded heat production
  • Each cell has its own cell fuse
  • Gas exhaust system
  • Pre-charge circuit for start-up
  • Black-out start, systems can start up when the ship is totally depowered, must have emergency supply battery 24V

PERFORMANCE AND LIFETIME

Like all batteries, also EPTechnologies batteries age, by usage and by calendar aging. Calendar aging is around 1% per year if kept below 30 deg storage temp and if stored at 50 to 60% SOC.

With repeated charging and discharging (cyclical ageing). The 6 year 75% SOC capacity guarantee for the batteries is only valid if below restrictions are followed. 

DoD: Depth of Discharge

SOC: State of Charge

Estimated Cycle Life assuming that

  • Never below 10% SOC better 20%
  • Never above 95% SOC better 80%
  • Average temp at 25°C, never above 40°C.
  • Usually max 1 C discharge
  • Usually max 0.5C chargeIs 8000 cycles and remaining capacity is 75%

Arrehenius Equation

We use the Arrhenius equation to calculate average temperature, as a result, the higher temperatures have higher impact. 

Guarantee

EPTechnologies guarantees the remaining capacity by the following graph depending on the DOD per cycle

STRING DATA

  • Each string can consist of 1 to 22 batteries in series for nominal, up to 844V if needed.
  • Each string has a string controller and a dasy chained com. cable, 20 kg each.
  • The string controllers have manual and remote disconnect switches and pre-charge

FOR MULTI-STRING TO PARALLEL

  • Pack control Unit PCU has double communication lines, one com. line is in stby, 10kg each. 
  • Optional slave PCU control unit that can take over if the master fails is an option.
  • Up to 24 Strings in parallel per pack controller.