Spring-Loaded PCB Thermal Coupling for EV Power Contacts

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Solution Overview

Problem

Existing electrical connection devices for electric vehicles face challenges in reliably achieving thermal coupling between circuit boards and power contacts, especially due to thickness tolerances and alignment issues, which can lead to overheating during high charging currents.

Innovation Solution

An electrical connection device with a circuit board positioned between power contacts and a housing, using a spring force device for thermal and mechanical coupling, and incorporating temperature sensors for monitoring, allowing for direct or indirect contact and ensuring reliable thermal and electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a circuit board is oriented perpendicular to the plug-in direction with high manufacturing precision requirements, then reliable thermal coupling can be achieved, but assembly complexity and production costs increase

Engineering Contradiction:
Improvethermal coupling reliabilityVSAvoidcircuit board positioning precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The circuit board is designed to be movable along its normal direction, transitioning from a fixed rigid position to a dynamic adjustable position. The spring force device enables the circuit board to automatically adapt to thickness variations of the power contact, ensuring reliable thermal coupling without requiring high manufacturing precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the positional parameter of the circuit board from fixed to variable. By allowing the circuit board to move within a certain range and use the spring force device to adjust the contact pressure, the system compensates for manufacturing tolerances and ensures consistent thermal coupling reliability.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a rigid fixed mounting method is used for the circuit board, then assembly is simple, but thermal coupling reliability decreases due to thickness tolerances

Engineering Contradiction:
Improveassembly simplicityVSAvoidthermal coupling reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The circuit board mounting is changed from rigid fixed to dynamically adjustable. The spring force device allows the circuit board to automatically adapt to power contact thickness variations, maintaining reliable thermal coupling while keeping the assembly process simple and tolerant of manufacturing variations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The circuit board assembly performs self-adjustment through the spring force device. During assembly, the circuit board automatically positions itself and applies appropriate contact pressure on the power contact, eliminating the need for precise pre-positioning or complex adjustment procedures.

Inventive Principle:
Principle #25Self-service

3Productivity

If higher charging currents are used for fast charging, then charging speed increases, but power contact temperature exceeds safety limits

Engineering Contradiction:
Improvecharging speedVSAvoidpower contact temperature
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The temperature sensor provides real-time feedback on the power contact temperature to the control unit. When the temperature approaches the safety limit during high current fast charging, the control unit adjusts the charging current accordingly, enabling safe fast charging operation.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The invention uses a composite structure combining the circuit board, spring force device, and temperature sensor to monitor and manage thermal conditions. This composite system enables safe operation at higher charging currents by providing continuous temperature monitoring and control.

Inventive Principle:
Principle #40Composite materials

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 design ensures reliable thermal and electrical coupling, compensates for thickness tolerances, simplifies assembly, and allows for resistance coding of power contacts, reducing overheating risks and production costs.

Implementation Method 1

the circuit board being braced between the power contact and the holding section by means of a spring force device arranged between the power contact and the holding section

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The circuit board is thermally coupled to the power contact directly or via the spring force device, and the at least one temperature sensor is arranged on the circuit board

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

Due to a charging current flowing through the power contact, the power contact inevitably heats up due to ohmic current heat losses

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3478531B1Electrical connection arrangement with thermal coupling of a printed circuit board employing a temperatur sensor
Publication Date: 2020.12.09 PHOENIX CONTACT E MOBILITY GMBH
  • EP3478531B1 patent drawingFigure 1A~1B
  • EP3478531B1 patent drawingFigure 2A~2C
  • EP3478531B1 patent drawingFigure 3A~3C

AI summary

The present invention discloses an electrical connection device (1) for coupling to a corresponding connecting apparatus and for transmitting electrical energy, wherein the electrical connection device (1) has - at least one power contact (40) which is arranged in a housing (10) of the electrical connection device (1) and is connected to said housing, and - at least one temperature sensor for determining a temperature of the power contact (40), wherein the electrical connection device (1) is characterized by the following features: - the electrical connection device (1) has a printed circuit board (20) which is arranged in the housing (10) of said electrical connection device and is arranged between the power contact (40) and a holding section (12) of the housing (10); - the printed circuit board (20) is clamped between the power contact (40) and the holding section (12) by means of a spring-force device (30) which is arranged between the power contact (40) and the holding section (12); - the printed circuit board (20) is thermally coupled to the power contact (40) directly or by means of the spring-force device (30); - the at least one temperature sensor is arranged on the printed circuit board (20).