Liquid-Cooled Junction Box Busbar Thermal Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High current flow in electric and hybrid automobiles generates excessive heat in electrical junction boxes, and increasing the cross-sectional area of conductive members to reduce resistance is impractical due to size constraints.
Innovation Solution
An electrical junction box design that immerses busbars and other heat-generating components in liquid coolant within a cooling case, allowing efficient heat transfer and cooling, while minimizing the size of the junction box and coolant usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross-sectional area of the conductive member is increased to reduce resistance value, then the resistance value is reduced, but the size of the electrical junction box increases
Solution Approach 1:
The patent introduces liquid coolant as an intermediary substance between the busbar and the external environment. The coolant absorbs heat from the busbar through direct contact, acting as a thermal mediator that transfers heat away from the conductive member without requiring increased cross-sectional area. This resolves the contradiction by providing an alternative heat dissipation pathway that maintains low resistance while controlling junction box size.
Solution Approach 2:
The patent extracts the heat dissipation function from the conductive member itself and separates it into a dedicated cooling system. Instead of relying solely on the busbar's cross-sectional area for thermal management, the heat extraction is delegated to the liquid coolant circulation system. This allows the busbar to maintain optimal electrical properties while the cooling system handles thermal management independently.
2Object-generated harmful factors
If the cross-sectional area of the conductive member is increased to reduce heat generation, then the heat generation is reduced, but the size of the electrical junction box increases
Solution Approach 1:
The patent converts the harmful heat generated by high current flow into a beneficial thermal gradient that drives efficient heat transfer to the liquid coolant. The high current conditions that generate excessive heat are transformed into an opportunity for enhanced cooling, as the temperature difference between the busbar and coolant creates optimal conditions for heat dissipation. This approach allows the system to handle high currents effectively without increasing size.
3Temperature
If conventional cooling methods are used, then cooling is provided, but the cooling efficiency is insufficient for high current applications
Solution Approach 1:
The patent employs a liquid coolant circulation system that utilizes hydraulic principles to achieve efficient heat transfer. The liquid coolant is pumped through channels in direct contact with the busbar, leveraging fluid dynamics to maximize thermal exchange. This hydraulic cooling approach provides superior cooling efficiency compared to conventional air cooling or passive methods, enabling the system to handle high currents effectively while maintaining appropriate temperatures.
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 effectively cools the electrical junction box, maintaining efficiency while keeping the junction box compact, by transferring heat generated during high current flow to the liquid coolant for dissipation.
Implementation Method 1
since the busbar is immersed in the liquid coolant, the heat that is generated by the busbar when current flows is transferred to the liquid coolant
Implementation Method 2
the liquid coolant that has been cooled can be allowed to flow into the case through the inlet port, and the liquid coolant whose temperature has been increased as a result of receiving the heat can be allowed to flow to the outside of the case
Data Source
AI summary
An electrical junction box configured to be disposed between a power supply and a load includes a cooling case that has an opening, a circuit assembly that is disposed closing the opening of the cooling case, and a liquid coolant that is stored in the cooling case. The circuit assembly has a case-facing surface that faces the cooling case, and includes a plurality of busbars that are disposed on the case-facing surface and constitute a conductive path between the power supply and the load. The busbars are immersed in the liquid coolant R.