Dual Closed-Loop Cooling Circuit for Electric Vehicle Thermal Management
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Solution Overview
Problem
Cooling circuits in electric vehicles, which include both electric motors and energy storage systems, face inefficiencies due to differing target temperatures and heat dissipation requirements for these two heat sources, leading to suboptimal cooling performance.
Innovation Solution
A dual closed-loop cooling circuit arrangement with separate low-temperature and medium-temperature circuits, each with its own pump and radiator, connected by controllable fluidic connections and valves for pressure adaptation and equalization, allowing for targeted pressure control and efficient cooling of both heat sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cooling circuit is used for both electric motor and energy storage, then the device complexity is reduced, but the cooling performance for both heat sources deteriorates due to differing target temperatures and heat dissipation requirements
Solution Approach 1:
The cooling circuit is segmented into two separate closed cooling circuits: a first cooling circuit for the electric motor and a second cooling circuit for the energy storage system. Each circuit has its own pump, radiator, and coolant flow path, allowing independent optimization of cooling parameters for each heat source while maintaining manageable system complexity through modular architecture
2Reliability
If separate cooling circuits are used for electric motor and energy storage, then the cooling performance for both heat sources is improved, but the device complexity increases due to multiple pumps, radiators, and fluidic connections
Solution Approach 1:
The first and second cooling circuits are designed with multi-functionality to reduce overall system complexity. The circuits can operate independently for separate cooling tasks or be connected through fluidic connections to share coolant flow paths when pressure conditions permit. The expansion tank in the first circuit can serve both circuits during pressure equalization, reducing the need for separate expansion tanks in each circuit
3Ease of operation
If pressure levels are not equalized between cooling circuits, then the system operation is simplified, but coolant flow stability deteriorates and may cause damage
Solution Approach 1:
A control device continuously monitors pressure levels in both cooling circuits and provides feedback control for the first and second valves. Based on real-time pressure differential measurements, the control device automatically adjusts valve positions to maintain proper pressure balance between circuits, ensuring stable coolant flow while allowing simplified operation through automated pressure equalization
4Device complexity
If the coolant temperature difference between circuits is not maintained, then the system design is simplified, but the cooling effectiveness for both heat sources deteriorates
Solution Approach 1:
Different temperature characteristics are assigned to different cooling circuits to optimize local cooling effectiveness. The first cooling circuit for the electric motor operates with lower coolant temperatures optimized for high heat flux components, while the second cooling circuit for energy storage operates with higher coolant temperatures suited for thermal mass cooling. This local quality differentiation ensures optimal cooling performance for each heat source type
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 configuration enables effective cooling of both electric motors and energy storage systems by maintaining defined pressure levels and temperature differences, preventing damage and ensuring optimal cooling performance.
Implementation Method 1
a first heat source, a first pump and a first radiator are provided in the first cooling circuit, wherein by means of the first pump a coolant can be conveyed to the first radiator and can be conveyed from the first radiator to the first heat source
Implementation Method 2
a second heat source, a second pump and a second radiator are provided in the second cooling circuit, wherein by means of the second pump a coolant can be conveyed to the second radiator and can be conveyed from the second radiator to the second heat source
Implementation Method 3
The expansion tank can implement a separation between a liquid phase and an air phase, such that in the presence of negative relative pressure air is drawn in, and in the presence of positive pressure air is discharged
Data Source
AI summary
A cooling circuit arrangement includes first and second closed cooling circuits. Each closed cooling circuit has a heat source, a pump and a radiator. By way of the first pump of the first circuit, a coolant can be conveyed to the first radiator and from the first radiator to the first heat source and from the latter to the first pump. By way of the second pump of the second circuit, a coolant can be conveyed to the second radiator and can be conveyed from the second radiator to the second heat source and from the latter to the second pump. Downstream of the first pump and of the second pump, there is provided a first fluidic connection which is controllable by a first valve. Upstream of the first pump and the second pump, there is provided a second fluidic connection which is controllable by a second valve.