Onboard Power Assembly Immersion Cooling for High Power Density
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Solution Overview
Problem
Existing liquid-cooled onboard power conversion systems face high thermal resistance and are unable to meet the heat dissipation requirements of increasing power density due to indirect cooling methods, and magnetic elements like transformers/inductors are inefficiently cooled by local glue filling, limiting the power density improvement.
Innovation Solution
A thermal management system that immerses power assemblies in insulating heat conductive fluid and uses coolant loops for direct and indirect cooling, with a combination of immersion and liquid cooling methods, including a first cooling loop for insulating heat conductive fluid circulation and a second loop for coolant circulation, facilitated by pumps and expandable air cushions for thermal regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If indirect liquid cooling mode with copper inlay and thermal interface materials is used, then the structure is simple to manufacture, but the thermal resistance is large and heat dissipation efficiency is poor
Solution Approach 1:
The patent removes the copper inlay and thermal interface materials from the cooling structure, replacing them with a direct liquid cooling approach where coolant flows through channels in direct contact with the power switch housing, eliminating the thermal resistance introduced by intermediate materials
Solution Approach 2:
The patent introduces a coolant as an intermediary substance that directly contacts the power switch housing through cooling channels, replacing the ineffective copper inlay and thermal interface materials with a fluid mediator that efficiently transfers heat away from the power electronics
2Ease of manufacture
If local glue filling or local dispensing is used for magnetic elements, then the structure is simple, but the unfilled parts are far from the cold plate and cooling efficiency is poor
Solution Approach 1:
The patent segments the cooling approach by providing separate cooling solutions for different components: power switches are cooled through integrated cooling channels in their housing, while magnetic elements are cooled through a separate liquid cooling plate with dedicated cooling channels, ensuring each component has optimized cooling without requiring complex filling operations
Solution Approach 2:
The patent uses a liquid cooling plate with cooling channels as an intermediary cooling structure for magnetic elements, replacing the inadequate local glue filling approach with a fluid-mediated cooling system that ensures efficient heat transfer from all surfaces of the magnetic elements
3Power
If power density is continuously improved, then the power conversion efficiency is higher, but the heat dissipation requirements become more difficult to meet
Solution Approach 1:
The patent employs hydraulic cooling through coolant flowing through precisely engineered cooling channels in both the power switch housing and the magnetic element cooling plate, using fluid dynamics to efficiently remove the increasing heat loads generated by higher power density conversions
Solution Approach 2:
The patent changes the thermal management parameters by transitioning from air cooling and indirect liquid cooling to direct liquid cooling with optimized coolant flow channels, adjusting the cooling system's heat transfer coefficients and flow rates to match the increased heat generation from higher power density operation
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
The system achieves uniform and sufficient cooling, reduces insulation clearance, and enhances power density by utilizing natural and forced convection of insulating heat conductive fluid and coolant, improving the thermal management of onboard power devices.
Implementation Method 1
the power switch inside the system transfers heat to the waterway surface through copper inlay, via holes and thermal interface materials, and then takes away heat through convective heat transfer of the coolant
Implementation Method 2
the inner cavity which is filled with insulating heat conductive fluid, the power assembly is immersed in the insulating heat conductive fluid
Implementation Method 3
the present disclosure is also used to regulate the thermal expansion and contraction of the insulating heat conductive fluid due to temperature changes by providing an expandable air cushion
Data Source
AI summary
The present disclosure discloses an onboard power device and a thermal management system, wherein the thermal management system comprises the onboard power device which comprises a power assembly comprising a plurality of electronic components and a shell comprising an inner cavity and a coolant passage that are isolated from each other, wherein the power assembly is disposed in the inner cavity which is filled with insulating heat conductive fluid, the power assembly being immersed in the insulating heat conductive fluid, and wherein a coolant flows through the coolant passage. The present disclosure allows the power assembly to be sufficiently and uniformly cooled by immersing in insulating heat conductive fluid, and by circulating coolant in the coolant passage of the onboard power device.