Ceramic Power Contactor Housing With Integrated Overheat Sensing

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Solution Overview

Problem

Power contactors in electric vehicles face reliability issues due to overheating caused by increased contact resistance, which cannot be detected externally and can lead to failure, and existing designs are not cost-effective for manufacturing.

Innovation Solution

Integration of a temperature sensor within the power contactor's housing body, made of ceramic material, allows for precise temperature measurement near the electrical contacts, simplifying control and assembly, and using a method like dry pressing to produce the housing body with a recess for the sensor, ensuring cost-effective and reliable production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a temperature sensor is integrated into the power contactor housing body, then temperature monitoring reliability is improved, but device complexity increases

Engineering Contradiction:
Improvetemperature monitoring reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The temperature sensor is integrated directly into the housing body of the power contactor, merging the monitoring function with the structural component. This eliminates the need for separate sensor housings and mounting mechanisms, thereby improving reliability while minimizing the increase in device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing body serves as an intermediary structure that both protects internal components and houses the temperature sensor. By incorporating the sensor into the housing itself rather than adding a separate mounting structure, the design achieves reliable temperature monitoring with minimal complexity increase.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the temperature sensor is arranged close to the electrical contacts, then temperature measurement accuracy is improved, but electrical insulation requirements worsen

Engineering Contradiction:
Improvetemperature measurement accuracyVSAvoidelectrical insulation requirements
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The housing body exhibits local quality differentiation where specific regions provide enhanced electrical insulation properties. The temperature sensor is positioned in zones where the housing material provides both thermal proximity to contacts for accurate measurement and sufficient electrical insulation to prevent interference.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The housing body utilizes composite material properties combining thermal conductivity for heat transfer to the sensor with electrical insulation characteristics. This allows the sensor to be positioned close to electrical contacts for accurate temperature measurement while the housing material prevents electrical interference.

Inventive Principle:
Principle #40Composite materials

3Temperature

If the housing body is made of ceramic material, then temperature resistance and electrical insulation are improved, but manufacturing complexity increases

Engineering Contradiction:
Improvetemperature resistanceVSAvoidmanufacturing complexity
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The recess for the temperature sensor is formed during the green compacting stage before sintering, rather than requiring post-sintering machining or drilling. This preliminary action simplifies manufacturing by utilizing the forming process itself to create the sensor mounting feature, reducing overall manufacturing complexity despite using ceramic material.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If the recess for the temperature sensor is formed during green compacting, then production cost is reduced, but manufacturing precision requirements worsen

Engineering Contradiction:
Improveproduction costVSAvoidmanufacturing precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The housing body manufacturing process is segmented into distinct stages: green compacting where the recess is formed, and sintering where the final product is completed. The recess geometry is designed to be formed during green compacting with tolerances suitable for that process, while the final precision requirements are met after sintering, optimizing both cost and precision.

Inventive Principle:
Principle #1Segmentation

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 integrated temperature sensor enables early detection of overheating, preventing functional failures and simplifying assembly, while the ceramic housing provides high temperature resistance and electrical insulation, enhancing the power contactor's reliability and manufacturing efficiency.

Implementation Method 1

the power contactor has at least one integrated temperature sensor (12)

Methodology Applied
Scientific EffectTemperature sensing: Thermistor

Implementation Method 2

the housing body at least partially encloses the contact chamber... made of ceramic material... provides high temperature resistance

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 3

the housing body at least partially encloses the contact chamber... provides electrical insulation

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Implementation Method 4

a time period for heat propagation from the electrical contact(s) does not exceed a predetermined duration

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3539142B1Power contactor and method for producing a housing body for the power contactor
Publication Date: 2024.01.24 TDK ELECTRONICS AG
  • EP3539142B1 patent drawingFigure 1
  • EP3539142B1 patent drawingFigure 2
  • EP3539142B1 patent drawingFigure 3a~3c

AI summary

The power contactor (1) comprises a first electrical contact (3) and a second electrical contact (4). The power contactor (1) also comprises a switch element (5), which can adopt an open position and a closed position, wherein the switch element contacts the first electrical contact (3) and the second electrical contact (4) with one another in the closed position, and wherein the first electrical contact (3) and the second electrical contact (4) are isolated from one another when the switch element is in the open position. In addition, the power contactor (1) comprises a temperature sensor (12) integrated into the power contactor (1), which is configured for detecting a temperature of the power contactor (1) at a predefined distance from the first electrical contact (3) and/or the second electrical contact (4).