Why Battery PCS Cooling Air Does Not Reverse When Power Does
A battery PCS changes electrical power in both directions. Charging and discharging both generate conversion losses, so the heat still needs a route out. The video follows an air-cooled PCS and separates its electrical power flow from its cooling-air path.
Follow the air through the process
Electrical power can travel both ways
A battery power conversion system, or PCS, charges a battery and returns power to the grid. Its cooling fans have a different job: removing conversion heat.
Charging also generates heat
During charging, the converter transfers power from the AC side to the DC battery side. Switching and conduction losses heat the power devices.
Discharging still generates heat
During discharge, electrical power travels the other way. Losses still produce heat inside the converter. The cooling-air direction does not have to follow the power direction.
Heat leaves through the same air path
In this air-cooled example, heat conducts into the metal heat sink. Air passes between the fins and carries heat to the outlet in both modes.
Match cooling to both operating modes
Check heat losses across the intended charging and discharging duties. The installed air path, ambient conditions and control strategy determine the cooling requirement.
Airflow function
- Move air through the power-device heat-sink channels.
- Remove conversion heat in charging and discharging modes.
- Provide the required airflow against the assembled passage resistance.
What can change the result
- A thermal design covers only one operating mode.
- Cooling air bypasses the power-device heat sink.
- Inlet air is too warm or recirculates from the discharge.
Start with the complete air path
Share your layout and the information you already have. Unknown values can be identified before a configuration is selected.
Match the fan to this air path
Electrical power reverses direction in a bidirectional PCS, but heat still needs to leave the electronics. Evaluate LONGWELL EC centrifugal components for the cooling path using the loss maps of both operating modes.
Where it sits
Carry conversion heat through the PCS heat sink and out of the cabinet during both charging and discharging.
Why consider this configuration
Electrical power reverses direction in a bidirectional PCS, but heat still needs to leave the electronics. Evaluate LONGWELL EC centrifugal components for the cooling path using the loss maps of both operating modes.
Check the result in your equipment
Application questions
Must the fan reverse when the PCS changes from charge to discharge?
Electrical power reverses direction, but conversion heat still moves from hotter devices into the cooling air. The illustrated fan keeps the same inlet and outlet.
Is PCS cooling the same as battery-cell cooling?
They are separate thermal duties. The PCS power electronics and the battery cells can use different cooling arrangements.
Can a liquid-cooled PCS use the same example?
Its heat path differs. A liquid loop carries heat to a separate exchanger, so both the liquid side and the exchanger air side need review.
Review PCS airflow in both modes
Share a PCS air-path drawing or existing fan model. Include charging and discharging losses, inlet-air conditions, heat-sink resistance and the required feedback and controls.
A layout, installation photos or your existing model is enough to start the discussion.