Anatomy of the battery cooling loop
Cold plates, pumps, chiller and radiator working together.
- Explain anatomy of the battery cooling loop at engineering level
- Read the numbers that define the behaviour
- Apply the idea to a real vehicle
Overview
The battery loop is the most tightly controlled circuit in the car because the cells it serves have the narrowest safe temperature window of any component.
In depth
Battery cooling loop explorer
Explore the components of the battery cooling circuit and switch between operating modes.
Hot day driving: High ambient heat load; chiller and radiator both working, fan at high duty. Pump duty 85%
Size a coolant flow
Coolant flow needed to hold a component at a target temperature.
ṁ = Q ÷ (c_p × ΔT_allowed)Rearranging the heat equation gives the mass flow required to carry away a known heat load within an allowed temperature rise. The radiator must then reject that same heat to ambient air.
Example: 6 kW with a 6 K allowed rise in glycol needs about 0.29 kg/s of flow.
- Radiator capacity falls sharply as ambient temperature approaches coolant temperature.
- Chillers borrow the refrigerant loop when the radiator alone cannot cope.
- Flow beyond about 0.5 kg/s per loop gives diminishing returns for large pump cost.
Key takeaways
- The battery loop combines cold plates, a pump, a radiator and a chiller.
- Pump speed is actively varied to match heat load, not run flat out.
- The chiller adds cooling capacity beyond what ambient air alone provides.
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