Liquid-Cooled EV Charging Cable Thermal Management
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Solution Overview
Problem
High-current charging of electric vehicles requires large, heavy, and expensive conductors that suffer from heat-related issues, reducing efficiency and safety, and increasing material consumption.
Innovation Solution
The implementation of liquid-cooled and gas-cooled charging cables, where electrically conductive cables are integrated with cooling systems, either through fluid circulation in liquid-cooled tubes or thermally conductive gases within a sealed sheath in gas-cooled designs, to manage heat and reduce material needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If high current (350 A) is used for fast charging, then charging time is reduced to 30-60 minutes, but the conductor requires large cross-sectional area (70-95 mm diameter), making it heavy and expensive
Solution Approach 1:
The cable is segmented into multiple smaller conductors (e.g., multiple 35 mm² strands instead of one large 95 mm² conductor) that are arranged in parallel. This segmentation allows the same current-carrying capacity to be achieved with reduced overall cross-sectional area and weight, while maintaining electrical performance through parallel current paths.
Solution Approach 2:
The patent introduces liquid cooling channels (hydraulic system) within the cable structure to actively remove heat from the conductors. This enables the use of smaller cross-sectional area conductors by preventing heat accumulation, thus reducing cable weight while maintaining fast charging capability through active thermal management.
2Loss of time
If high current (350 A) is used for fast charging, then charging time is reduced, but the conductor becomes very hot, increasing electrical resistance and reducing charging efficiency
Solution Approach 1:
Liquid cooling channels are integrated into the cable structure, allowing coolant to flow through tubes surrounding or within the conductors. This hydraulic cooling system continuously removes heat from the high-current conductors, maintaining low electrical resistance and high charging efficiency throughout the fast charging process.
Solution Approach 2:
The patent changes the thermal parameter of the cable system by introducing active cooling, which maintains the conductor temperature at a lower operating point despite high current flow. This parameter control (temperature) prevents the exponential increase in electrical resistance that would otherwise occur, sustaining charging efficiency.
3Loss of time
If high current (350 A) is used for fast charging, then charging time is reduced, but thermal expansion and contraction cycles create stresses in connected parts, decreasing their lifetime
Solution Approach 1:
The liquid cooling system continuously maintains thermal equilibrium in the cable and connected components, preventing the thermal expansion and contraction cycles that occur with uncooled high-current cables. This stable thermal environment significantly reduces mechanical stress on connectors and solder joints, extending the lifetime of connected parts.
Solution Approach 2:
The cooling channels are designed to anticipate and prevent thermal stress accumulation before it can damage connected components. By maintaining constant thermal management during charging cycles, the system cushions connected parts from the damaging effects of repeated thermal expansion and contraction.
4Power
If large cross-sectional area conductor is used to carry high current, then charging capability is improved, but the cable becomes expensive due to increased copper consumption
Solution Approach 1:
Instead of using one large-diameter conductor that would require excessive copper, the patent segments the current path into multiple smaller parallel conductors. This segmentation achieves the same total current-carrying capacity with optimized copper usage, reducing material consumption and cost while maintaining high power charging capability.
Solution Approach 2:
The liquid cooling system enables the use of smaller cross-sectional area conductors by actively removing heat, thereby reducing copper consumption. The cooling channels allow the cable to sustain high current densities without overheating, achieving the same power transmission capability with less copper material.
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 solution decreases charging time, enhances safety, reduces material costs, and improves the reliability of electric vehicles by effectively managing heat and minimizing material usage, thereby promoting the adoption and use of electric vehicles.
Implementation Method 1
A set of cooling tubes corresponds to each cable, each set including one or more cooling tubes. Each cooling tube includes an inlet and an outlet, both at the first end of the cable, a forward part in thermal contact with the cable, the forward part beginning at the inlet and extending from the first end to the second end, and a reverse part in thermal contact with the cable
Implementation Method 2
a working fluid can flow through each cooling tube from the inlet through the forward part and the reverse part to the outlet
Implementation Method 3
A thermally conductive sheath sealingly encloses at least part of the one or more cables, wherein there is a sealed volume between an interior surface of the sheath and the exterior surface of the one or more cables, and a thermally conductive and electrically insulating gas occupies the sealed volume
Implementation Method 4
a thermally conductive and electrically insulating gas occupies the sealed volume
Data Source
AI summary
Embodiments of a liquid-cooled charging cable are described. The charging cable includes one or more electrically conductive cables having a first end and a second end. Each cable has a set of one or more cooling tubes. Each cooling tube includes an inlet and an outlet, both at the first end of the cable, a forward part in thermal contact with the cable, the forward part beginning at the inlet and extending from the first end to the second end, and a reverse part in thermal contact with the cable, the reverse part extending from the second end to the first end and ending at the outlet. The forward and reverse parts together form a continuous fluid path between the inlet and the outlet, so that a working fluid can flow through each cooling tube from the inlet through the forward part and the reverse part to the outlet.