Liquid-Cooled Contact Element for High-Power Plug Connections

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Solution Overview

Problem

Current plug connection devices for electric vehicles face challenges in efficiently cooling current-carrying elements during high-power charging, leading to increased ohmic resistance and reduced charging efficiency due to heat buildup, especially at transition points, and limited cooling options within compact vehicle packaging.

Innovation Solution

A contacting element with a heat sink that incorporates a coolant chamber, made of conductive materials like copper or aluminum, which allows for active cooling by flowing an electrically insulating coolant through the chamber, effectively dissipating heat generated by electrical currents and reducing ohmic resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high charging power is used to charge the traction battery quickly, then charging speed is improved, but current-carrying elements heat up and ohmic resistance increases

Engineering Contradiction:
Improvecharging speedVSAvoidtemperature of current-carrying elements
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The heat sink is divided into multiple cooling channels that are distributed throughout the structure, allowing heat to be dissipated from multiple locations simultaneously. This segmentation of the cooling function enables more effective heat management at high charging powers.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A coolant is introduced as an intermediary substance that absorbs heat from the current-carrying elements through the heat sink. The coolant circulates through closed channels, transferring thermal energy from the hot contact elements to a cooling plate or external cooling system, thereby preventing excessive temperature rise.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If cooling systems are added to cool current-carrying elements, then temperature control is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature control of current-carrying elementsVSAvoidcomplexity of cooling system
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The heat sink is merged with the contacting element itself, forming an integrated component rather than a separate attachment. The cooling channels are embedded within the heat sink structure, combining the electrical connection function and thermal management function into a single unified component, thereby reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The heat sink serves multiple functions simultaneously: it provides mechanical support for the contacting element, establishes electrical connection, and acts as a heat exchanger for thermal management. This multi-functionality eliminates the need for separate cooling components, reducing device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Temperature

If heat dissipation structures are added to current-carrying elements, then cooling efficiency is improved, but installation space requirements increase

Engineering Contradiction:
Improvecooling efficiency of current-carrying elementsVSAvoidinstallation space of heat dissipation structure
Core Design Contradiction:
TemperatureVSVolume of moving object

Solution Approach 1:

The cooling channels are nested within the heat sink structure itself, with coolant flow paths embedded inside the solid material. This nesting approach allows the cooling function to be contained within the existing footprint of the contacting element, avoiding external additions that would increase installation space requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The heat sink extends in the direction of heat flow (typically perpendicular to the contact surface), utilizing the third dimension to provide cooling capacity without increasing the planar footprint. This dimensional approach allows efficient heat dissipation while maintaining compact installation space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution enables efficient cooling of current-carrying elements, allowing for higher charging powers and reduced charging times by actively managing heat through the coolant system, while also being space-efficient and reliable.

Implementation Method 1

The heat sink is made of an electrically conductive material and is configured to conduct heat away from the current-carrying elements

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a coolant circuit, by means of which the coolant can be driven through the coolant channel system

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The coolant chamber is fluidly connected to a coolant circuit... the coolant is driven through the coolant channel system... heat generated by electrical currents is conducted into the heat sink material and thereby flowed off by the coolant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4324686A1Contact element for a plug-in connection device and plug-in connection device
Publication Date: 2024.02.21 LISA DRAXLMAIER GMBH
  • EP4324686A1 patent drawingFigure 1~2
  • EP4324686A1 patent drawingFigure 3~4
  • EP4324686A1 patent drawingFigure 5~9

AI summary

The invention relates to a contacting element (1) for a plug connection device (2) and the plug connection device (2) by means of which an electrically conductive plug connection can be established. The contacting element (1) comprises a heat sink (3) which defines a coolant chamber (8) through which an electrically non-conductive coolant flows, is made of an electrically conductive material, and has a coolant chamber portion (15) and a coolant chamber cover (16) which are connected to each other. An inlet opening (4) and an outlet opening (5) penetrate a coolant chamber cover (16), open into the coolant chamber (8), and are configured to be fluidically connected on the outside of the heat sink (3) to an inlet channel of a coolant circuit.Furthermore, a first connecting element (6) of the contacting element (1) is arranged to form a planar electrically conductive and thermally conductive connecting device (32) between a contacting surface (33) of the heat sink (3) and a corresponding contacting surface (34) of a busbar (35) with a corresponding, second connecting element (31) of the plug-in connection device (2).