Architecture
The 20C1600K BESS container has modular architecture with:
Liquid cooled battery packs made with LFP cells and a Battery Management Unit (BMU).
Battery cluster / strings with a Controller (CMU).
Separate AC/DC Inverters (PCS) for each battery string.
Liquid temperature control system and HVAC dehumidifier.
Firefighting system, backup power.
BESS controller (GPC) to handle safety, automatic operation and data and control communication with external BESS and EMS SCADA.
Container description
The 20C1600K system uses a customized container with a stronger load-bearing case and reinforcement steel frames in the middle while maintaining the same dimensions as a 20ft HC container.
Anti-corrosion materials are used for the paint of the container shell to improve the anti-corrosion performance of the container.
The shell interlayer is installed with 50mm thermal insulation rock wool to improve the thermal insulation performance of the system.
In the battery compartment, there are battery Strings, liquid cooling unit, air conditioners for dehumidification and cable slots, etc. Battery Strings are installed on both sides of the battery container, lighting, thermal sensors, smoke sensors, firefighting pipe and other equipment are installed above the side aisle.
In the electrical compartment, there are PCS, GPC, Firefighting Control System, power distribution system, BESS controller with 24h back up power, air conditioner and auxiliary power supply distribution system.
Independent string inverters
Over time, charge and discharge performance of parallel battery racks will vary due to divergences in the internal resistance of the cells.
Tests have shown that capacity loss increases by up to 2 % per year when eight racks are connected in parallel compared to non-parallel connections. Batteries connected in parallel can also lead to current loops and barrel effects due to voltage differences, resulting in a reduction in the usable capacity of the system.
Tests data also show that when two battery racks are connected in parallel and the SOC differs by 8%, after a complete charge-discharge cycle, the total discharge capacity of the energy storage system with independent PCS inverters (ACDC or DCDC) is increased by up to 7%.
Specifications
AC side
Nominal capacity | 1,600kW/3,086kWh |
Rated AC output power | 1,600kW |
Max. AC output power | 1,760kVA |
Rated output voltage | 690V |
Output voltage range | 586.5~759Vac (Optional) |
Rated frequency | 50/60Hz |
Rated output current | 8×167.3Aac |
Adjustable power factor | 0.1~1 leading or lagging (Controllable) |
THDi | <1.5% (at rated power) |
Max efficiency | 98.7% |
Output wiring | 3 phase 3 wire |
DC side
Rated voltage | 1,228.8Vdc |
Lower voltage limit | 1,075.2Vdc |
Upper voltage limit | 1,363.2Vdc |
Rated current | 8*162.7A |
Battery cell capacity | 314Ah |
Total number of cells | 3,072 |
Cells per battery module | 48 in series |
Battery modules per string | 8 in series |
Strings per container | 8 in parallel |
Actual capacity | 3,086 kWh |
General
BESS Container dimensions | W6,058xD2,438xH2,896mm |
BESS weight | 31T |
IP protection | IP54 |
Operating temperature range | Normal: -35~45℃ |
Relative humidity | 0~95% (non-condensing) |
Max working altitude | 2,000m/6,562ft |
BESS cooling | Liquid cooling & air conditioner |
Control system communication | Modbus TCP |
Certifications | UL9540, IEC62619, EN 50549-2, IEC 61000-2&-4, IEC 62477, UL 1973, EN50549-2, IEEE 1547, FCC, UN3536 |
BESS capacity over project life
The evaluation point is on MV transformer POC output point, considering the auxiliary electrical loss and internal consumption.
Cells are rated to 10,000 full cycles (0.5P 25°C 100% DOD) to > 70% of initial capacity. In normal operating conditions, BESS is rated at 9,000 full cycles over 12 to 15 years to > 70% of initial capacity (see below degradation curves).
Most likely scenario: 1 full cycle per day or about 365 full cycles per year over 15 years at 0.5P rate.
High usage scenario: up to 2 full cycles per day (about 700 full cycles per year) over 15 years at 0.5P rate.
BESS energy efficiency
Measurement point | Single trip efficiency | Round trip efficiency |
Battery | 97.60% | 95.26% |
DC-PCS Cable | 99.80% | 94.88% |
PCS | 98.50% | 92.05% |
PCS-MCCB | 99.90% | 91.87% |
MV Transformer | 98.50% | 89.13% |
BESS MV transformer POC | 99.80% | 88.78% |
Accumulated Efficiency BESS AC BUS | 95.85% | 91.87% |
Accumulated Efficiency MV POC | 94.22% | 88.78% |
Certifications
The 20C1600K is fully certified according to UL and CE latest safety standards and thermal runaway tested as per UL9540A:
UL9540 certified.
UL9540A thermal runaway certified.
UL1973 certified.
IEC 62619 certified.
CE-LVD and CE-EMC.
UL1741, IEC 62477, EN 50549-1&-2, LVD for PCS .
UN38.3, UN3536, etc.
Fingrid SJV2019 certified by TUV for PCS.