Part 4: Equipment-level inspection and operation and maintenance SOP of the thermal management and temperature control system on the energy storage side of the photovoltaic power station
This article corresponds to the panoramic topology diagram of the energy storage power station [Module 4: Thermal Management and Temperature Control System], covering the peripheral mechanical protection of the battery compartment, door anti-condensation and slight positive pressure, liquid cooling source unit (Chiller), expansion tank, coolant water quality analysis and replacement SOP, and air-cooled air-conditioning system.
1. SOP for battery compartment peripheral mechanical protection, sealing to prevent condensation and micro-positive pressure system maintenance
The battery compartment is usually an explosion-proof structure of a 20-foot or 40-foot standard container, and the protection level must reach IP54 / IP65.
(1) Hatch door mechanical seal and anti-condensation control
Inspection of hatch sealing: Check the EPDM rubber sealing strips on all sides of the battery hatch. It is required that there is no hardening, cracking, peeling or powdering; the hatch is closed and buckled tightly, and there is no gap for light transmission. Check the three-point anti-theft lock and hinge, and add anti-rust grease. Check that the rainproof eaves and drainage channels are not damaged or blocked.
Anti-condensation and micro-positive pressure system maintenance:
Anti-condensation control: When the relative humidity in the cabin is ≥ 70% RH, the anti-condensation heater in the cabin must start automatically. Check that there is no accumulation of debris on the surface of the heater and no burning smell.
Slightly positive pressure control: A battery cabin equipped with a fresh air system must maintain a slightly positive pressure of 10 ~ 30 Pa in the cabin to prevent the intrusion of sand, dust and high-humidity air outside the cabin.
(2) Maintenance SOP for Explosive Vent Panel
The explosion relief device is the ultimate safety barrier for physical and directional pressure relief when the battery undergoes thermal runaway and produces a large amount of flammable gas, resulting in overpressure in the cabin.
Pre-tightening force inspection: Check the explosion vent panel and breakable bolts on the top of the container. The tightening torque of the bolts must be strictly controlled at 10.0 ± 1.0 N·m (too tight will cause the explosion to fail when overpressure occurs, and too loose will cause the seal to fail).
Safety distance: It is strictly prohibited to lay any cables, bridges or pile debris within 3 meters above the explosion vent and in the direction of the injection; there should be no obstruction by the explosion-proof bird net.
Explosion vent sensor: Check the extreme position travel switch attached to the explosion vent panel. When testing the action of the travel switch, SCADA must receive a "cabin explosion alarm" within <1s.
2. Equipment-level inspection and maintenance SOP for thermal management liquid cold source unit (Chiller unit)
The liquid cooling thermal management system circulates coolant (ethylene glycol aqueous solution) in the cold plate of the battery pack to control the battery core temperature at 20 ℃ ~ 30 ℃. The maximum temperature difference of the battery cells in the entire cabin is ≤ 3.0 ℃.
(1) Maintenance of circulating water pump and expansion tank
Circulating water pump operation inspection: Check the three-phase operating current balance of the water pump (deviation < 2%); use a sound level meter to measure the water pump bearing noise, which must be < 65 dB.
Check the water pump inlet and outlet pressure gauges. The pressure difference between inlet and outlet ΔP = Pout - Pin must be stable between 0.15 ~ 0.30 MPa. If the pressure difference is < 0.08 MPa, it means that the water pump is corroded or the pipeline is seriously blocked; if the pressure difference is > 0.40 MPa, it means that the pipeline is seriously blocked. The water pump mechanical seal has no leakage or water leakage.
Expansion Tank (Expansion Tank) precharge pressure verification: The expansion tank is used to absorb the volume changes of the coolant's thermal expansion and contraction and to suppress water hammer.
Verification SOP: When the water pump stops running and the pipeline is depressurized, use a pressure gauge to measure the nitrogen pressure at the valve at the top of the expansion tank. The standard pre-charge pressure must be 0.10 ~ 0.15 MPa. If liquid spurts out when the valve is pressed, the internal rubber diaphragm is ruptured and the expansion tank must be replaced.
(2) Maintenance of condenser and compressor
Cleaning of condenser fins: Use dry compressed air or high-pressure water gun (pressure < 0.3 MPa) every quarter to flush the dust accumulated on the aluminum fins of the condenser to ensure the cooling air volume.
Compressor refrigerant pressure detection: Check the high-pressure side pressure (usually 1.5 ~ 2.2 MPa) and low-pressure side pressure (usually 0.3 ~ 0.5 MPa, taking R410A / R134a refrigerant as an example) of the refrigeration compressor. There are no continuous air bubbles in the sight glass and no traces of refrigerant leakage.
(3) Three-way electronic regulating valve and PTC liquid heater
Three-way electronic control valve action proportion verification: The three-way valve automatically adjusts the proportion of coolant flowing through the refrigeration evaporator or bypass pipeline according to the inlet and outlet water temperature. Check the response of the stepper motor, there must be no jamming during the switching of opening 0% ➔ 100%, and the opening feedback error is < 2%.
PTC liquid heater maintenance (low temperature environment): When the ambient temperature is <5°C and the battery is in a low temperature state, the PTC heater starts to heat the coolant. Use a 1000V megger to measure the insulation resistance of the PTC heating tube to ground, which must be ≥ 100 MΩ; measure the balance of the PTC three-phase resistance to ensure that the low-temperature heating function is normal.
3. Coolant water quality analysis, Y-type filter cleaning, fluid replenishment and exhaust SOP
Coolant is the "blood" of the liquid cooling system. Deterioration of water quality will cause corrosion and scaling of the liquid cooling plate or cause the breakdown of the battery's high-voltage insulation to ground.
(1) Coolant key water quality testing standard table
(2) SOP for the entire process of Y-type filter cleaning and pipeline replenishment and exhaust
Step 1: Stop the water pump of the liquid cooling unit, cut off the main power supply, and close the main water inlet and outlet valve of the liquid cooling unit.
Step 2: Connect the hose to the low drain valve, drain about 5L of coolant, and reduce the pipeline pressure to 0 MPa.
Step 3: Use a wrench to unscrew the nut at the bottom of the Y-type filter and take out the 100-mesh stainless steel filter.
Step 4: Rinse the scale, impurities and metal shavings trapped in the filter with clean water, blow dry with compressed air, replace the fluororubber (FKM) sealing ring and install it back.
Step 5: Connect the electric filling pump to the liquid filling port and inject the original premixed glycol coolant until the expansion tank level reaches 2/3 of the mark.
Step 6: Start the water pump to circulate at low speed for 10 minutes, and open the exhaust valve at the highest point of the battery compartment to exhaust.
Step 7: When the exhaust valve no longer sprays bubbles and the pressure gauge stabilizes at 0.18 ~ 0.22 MPa, tighten the exhaust valve and complete the fluid replenishment and exhaust.
4. Equipment-level maintenance of cabinet air-cooled air-conditioning system (air-cooled power station/auxiliary air-cooled)
Evaporator/condenser and fan: Check the running current balance of the internal and external circulation fans, and there is no abnormal noise; clean the evaporator dust filter.
Drainage and condensate water catchment pan: Check that the condensate water drainage hose is unobstructed and that there is no accumulation of water in the water catchment pan that could cause algae to become clogged.
Refrigerant leakage inspection: Use an electronic leak detector to detect the copper pipe welding joints to ensure that there is no leakage of pressure difference and refrigerant.
Photovoltaic power station energy storage side thermal management temperature control system equipment level inspection on-site inspection sign-in form
Power station name: _______________________________ Inspection date: ____ month ____ day, 2026
Inspection area: periphery of battery compartment and liquid cooling unit (Chiller) area Inspection person in charge: ____________________
1. Field equipment inspection and test data records:
2. Inspection defect registration and defect elimination dispatch:
3. Inspection sign-in and review signature:
Inspection engineer (signature): _______________ Supervision engineer (signature): _______________
Review (signature) of the shift leader: _______________ Sign-in and filing time: ____ hour on ____ month ____ day 2026