LFP Flashcards
What does LFP Composition consist of?
The electrolyte, which contains the lithium ions
The separator, allows lithium ions to flow through the battery while preventing the movement of electrons
The cathode, where lithium ions are stored until the battery is charged
The anode, where lithium ions are stored until the battery discharges
The better cathode is at absorbing Lithium ions the better the mileage/SOH of the battery
Popular NMC Batteries
Model Capacity Price*
Tesla Powerwall 13.5 kWh $8,500
LG RESU10H Prime 9.6 kWh $7,000
Generac PWRCell 9 kWh $10,000
Popular LFP Batteries
Model Capacity Price
sonnenCore 10 kWh $9,500
Enphase IQ 10 10.08 kWh $9,000
BYD Battery Box HVS 10.24 kWh $7,000
It’s important to consider how much electricity you’re able to get out of your battery to truly determine what’s the best value
The easiest way to explain this is with an example. Let’s compare the sonnenCore battery with the LG Chem Prime
sonnenCoreLG Chem PrimeChemistry
LFP NMC
Capacity 10 kWh 10 kWh
Cost (before installation) $9,500 $7,000
Energy output during warranty period*58,000 kWh 32,000 kWh
Comparing sonnenCore and LG Chem Prime solar batteries
Augmentation Size on Storage Blocks
~ 500 KWH on a 4MVA system
- RTE and usable energy for 0.5CP, 0.25CP, 0.1CP that CATL guarantees.
- Degradation tool:
- 1 cycle/day at 0.5CP and 0.25CP for rack. How the ambient temperature will impact it?
- 1 cycle/day at 0.5CP with i.e. #20 racks in parallel.
- 1 cycle/day at 0.25CP with i.e. 30-40 racks in parallel.
- Auxiliary consumptions
- i.e. 1 cycle/day at 0.5CP and 0.25CP for rack in different temperature conditions.
- 2D, 3D mechanical drawings.
- Lifting method (weight, lifting points and center of gravity);
- System interfaces: mechanical (how and where to anchor the rack, wires entries etc.), DC power wires and AC auxiliary cross section and terminal required, communication wire and terminal required (max wires length).
- Short circuit current test report, arc-flash calculation, MSD type.
- BMS mech drawing, electrical and communication interfaces and requirements.
- What is the rating of the fuse on each rack? provide the datasheet.
- Thermal simulation/test results.
- Seismic simulation approved anchoring. After a seismic event like IBC high seismic area (IV), how does the rack react?
- SOC error reset strategy
- MBMU: Communication with rack’s SBMU is via Canbus 2.0, max distance is 50m, all racks are connected in daisy chain. Andy will send common repeater datasheet
- CATL is working with DNV-GL for all product fleet
- Rack fuse is 400A, 250kA
IP65 vs IP54
Issue of the Arizona fire, the container was an IP54 with no ventilation and no over-pressure rupture risk, when the fire Marshalls opened the container door they vented adding oxygen that led to the deflagration. Measuring in addition to the thermal runaway spread also the gas concentration and kind of gas helping you to understand the level of danger
Stat-X - how to calculate right size for the canister?
The agent calculation, kg needed
Seismic
- IBC/ASCE values (SS,SMS,SDS etc), California building code 2019 and new IBC as well as ASCE, the rail “Z,Y” simulation result is close to the tensile failure, what is the margin CATL uses?
- Looking the number in this simulation the rack will move/bend/oscillate, has CATL performed simulations to the inner modules to understand what will the impact be on them?
- Will the max acceleration pass the max acceleration a module may withstand?
Short Circuit Current
CATL melting time is around 0.7ms and the clearing time is around 1.135ms
SCC value melting time and clearing time should be added to spec
Incoming/outgoing section of CC panel. Red/Yellow black conductors are going to PCS, red jacket conductors are DC feeds from other two battery cabinets
No means of disconnect from PCS to isolate this section and work on it de energized if the entire PCS section is not de-energized. Other two associated cabinets have no means of being disconnected from this section
Almost impossible to replace the DC fuses short of disassembling entire front section including removing the NADER disconnect (above the orange insulator, not shown).
Type of insulating materials used. The orange piece in picture appears as solid metal and sipped in some sort of insulating material or coated
Explain how the incoming Aux power conductors are routed and connected to 225 Amp CB in this compartment.
Provide specifications for these buses used to feed all distribution breakers.
MV, LV Codes for AC/DC Panel
Provide details on lugs and crimping methodology.
Provide detailed BOM and UL certification for all components used, including but not limited to wires, sleeves, lugs, fuse holders, insulation wraps/covers and shrink tubes, terminal blocks and circuit breakers/disconnects.
Provide information and function for SPD (in 480 VAC compartment).
Equipment grounds?
480 VAC Color coding should be per NEC
Panduit used as wire way should be rated for 480VAC circuits (only control wires).
External service disconnect required for CC cabinet – NEC Code requirement section(s): 408.3(F4), 408.5, 409.30
Battery Container feeding CC panel require Disconnecting means – 408.4(a)
HVAC disconnecting means on container 2 and 3 : 705.2010.NEC Code 705.16, 705.20., 705.21
Provide clearances and insulation material used on the three-phase buses
Provide details on how this bussing is supported.
Explain how this Buss is being protected from accidental contact. Some area’s may be exposed and is 480 V
Code Issues Main DC Disconnect
CC Panel Main DC Contactor is required to have a means of operation and visual verification external to the dead front/panel door. An E-Stop is not sufficient. (UL 508A Section 31.2.4 pg 56)
Servicing: How do you change any components?
Fuses, Disconnect Switches, bus Bars and connections?
UPS section above the 2500 AMP molded disconnect switch
Provide detail how this section is isolated from incoming DC section
Provide details how the UPS is cooled and ensure air circulation is adequate
Thermal management design needed to indicate proper cooling of this compartment.
Provide details how to remove and work on the UPS system if needed.
Procedure on how to test, service and replace components on the section above UPS compartment.
Outgoing cables (to PCS) 1500VDC Section
Procedure on replacing the 2500 AMP Fuse if required
Fuse and cable sizing needs to be verified in compliance with NEC
Fusing & Isolation
Each DC conductor exiting containers should be provided with an Isolating disconnect and Overcurrent protection.
Its highly likely incremental OC protection (Fusing) will be required at some interval DC Bus/Battery rack aggregation.
Fusing is like required to protect the Bus/container-to-container cables from a bi-directional fault current coming from Inverters and Battery racks simultaneously. This fusing needs to be determined from a complete DC short circuit analysis scenario
Common Questions
Provide detailed BOM with cutsheets and UL Listing information
NEC Code non-compliances : 480.6(a,d)
Note on cable schedule/Routing:
All cables co-located in cable tray at bottom of container, comms and Power Cable to be segregated throughout the entire cabinets.
Proposed FATs should include resistance testing of bus bar bolted connections
Arc Flash Label for Large Eqp
see nfpa 110.16b
