BEV Power Electronics Cooling with Variable Coolant Flow
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Solution Overview
Problem
Existing cooling systems for battery electric vehicles (BEVs) maintain a constant coolant volume flow, which is inefficient as it exceeds the actual cooling demand of power electronics and electric machines, thereby reducing the vehicle's range.
Innovation Solution
A needs-based cooling system that calculates a target coolant volume flow based on the current temperature of power electronic components, coolant temperature, and power loss of the drive unit, allowing for dynamic adjustment of the coolant flow to match the actual cooling demand.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed volume flow is maintained to ensure full cooling capability, then the maximum power loss can be taken away, but the power consumption of the coolant pump increases unnecessarily in most operating instances
Solution Approach 1:
The patent applies dynamics by transitioning from a static fixed volume flow system to a dynamic variable volume flow system. The coolant pump's volume flow is continuously adjusted based on real-time temperature measurements from power electronic components and electric machines, allowing the system to adapt to varying thermal loads and minimize energy consumption while maintaining adequate cooling capability.
Solution Approach 2:
The patent implements parameter changes by modifying the volume flow parameter of the coolant pump based on operating conditions. The control unit calculates the required volume flow as a function of component temperatures, power losses, and ambient conditions, then adjusts the pump operation accordingly. This allows the system to use higher volume flows only when thermal conditions require them, rather than maintaining a constant high flow rate.
2Reliability
If a high volume flow is used to ensure adequate cooling, then the cooling demand is met, but the vehicle range is reduced due to increased energy consumption
Solution Approach 1:
The system dynamically adjusts the coolant volume flow to match the actual thermal demand of power electronic components and electric machines. By continuously monitoring temperatures and calculating required cooling capacity, the pump operates at optimal flow rates rather than constant high flow, thereby reducing energy losses and extending vehicle range without compromising cooling effectiveness.
Solution Approach 2:
The patent converts the previously harmful effect of excessive cooling (wasted energy) into a beneficial outcome (extended range). By implementing needs-based cooling control, the system recovers energy that was previously lost through unnecessary pump operation, effectively turning the over-cooling problem into a range extension solution.
3Reliability
If a fixed volume flow is maintained for all operating conditions, then the maximum cooling capability is available, but the system cannot adapt to actual cooling demand variations
Solution Approach 1:
The patent implements feedback control by continuously measuring temperatures of power electronic components and electric machines, then using this information to adjust the coolant volume flow. The control unit receives temperature data, calculates the actual cooling demand based on power losses and thermal conditions, and regulates the pump accordingly. This closed-loop feedback mechanism enables the system to adapt to varying cooling demands while maintaining maximum capability when needed.
Solution Approach 2:
The system transitions from a static fixed-flow configuration to a dynamic variable-flow system that continuously adapts to operating conditions. The volume flow is adjusted in real-time based on temperature measurements and calculated cooling demands, allowing the system to respond appropriately to varying thermal loads across different operating scenarios.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the power demand for water cooling, leading to increased vehicle range and efficiency, as the coolant pump's power consumption decreases with reduced volume flow, aligning with the actual operating conditions.
Implementation Method 1
the cooling function of the components is generally realized with the aid of water cooling by a mixture of water and glycol. This mixture is delivered by a coolant pump with a given volume flow Q by cooling hoses through the components
Implementation Method 2
This mixture is delivered by a coolant pump with a given volume flow Q by cooling hoses through the components
Implementation Method 3
This mixture is delivered by a coolant pump with a given volume flow Q
Data Source
AI summary
A system and a method for needs-based cooling of the power electronics and the E-machine of a battery electric powered motor vehicle.