EV Connector Heat Retaining Cover for Accurate Temperature Sensing

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Solution Overview

Problem

Existing connectors for electric vehicles face challenges in accurately measuring terminal fitting temperatures due to displacement of thermistors, which reduces temperature detection sensitivity and fails to detect abnormal heat generation effectively.

Innovation Solution

A connector design that includes heat retaining covers to improve heat transfer and uniformity, ensuring temperature sensors remain in contact with the heat generating portions, even if displaced, and are securely attached to the terminal fittings with seal members to prevent water ingress and enhance insulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a thermistor is mounted to detect temperature at the terminal fitting, then temperature detection capability is improved, but the thermistor may be displaced due to clearance and shrinkage, reducing detection sensitivity

Engineering Contradiction:

Improvetemperature detection sensitivityVSAvoidthermistor position stability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

A heat retaining cover is introduced as an intermediary component between the thermistor and the terminal fitting. This cover retains heat around the terminal fitting and ensures that even if the thermistor is slightly displaced, it remains within the heat-retaining zone, maintaining detection sensitivity while accommodating position variations due to clearance and shrinkage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The heat retaining cover is designed with dimensions and material properties that anticipate and compensate for thermal shrinkage and clearance effects before they impact measurement accuracy. By pre-establishing a heat-retaining environment, the system cushions against the adverse effects of thermistor displacement.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Productivity

If high current flows during battery charging, then charging speed is improved, but temperature of the charging connector and electric wire increases, causing electrical resistance to increase and potential damage

Engineering Contradiction:

Improvecharging speedVSAvoidconnector temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The temperature detection system using the thermistor provides real-time feedback on the temperature of the terminal fitting and electric wire. This feedback enables the charging system to monitor temperature conditions and adjust charging parameters or terminate charging when temperature thresholds are exceeded, preventing overheating damage while allowing high-current fast charging under safe conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The invention replaces passive thermal management with an active sensing and monitoring system. Instead of relying solely on thermal conduction and natural cooling, the thermistor-based detection system enables electronic control and regulation of the charging process based on real-time temperature measurements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If the thermistor is attached to the terminal fitting, then temperature measurement is achieved, but the attachment structure becomes complex and manufacturing difficulty increases

Engineering Contradiction:

Improvetemperature measurement accuracyVSAvoidassembly complexity

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The heat retaining cover is integrated with the terminal fitting assembly, combining the functions of heat retention, structural support, and thermistor mounting into a single unified component. This merging reduces the number of separate parts and simplifies the manufacturing and assembly process while maintaining effective temperature measurement.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for accurate temperature measurement of terminal fittings without reducing sensitivity, preventing overheating and resistance increases, while maintaining waterproofing and improving energization performance.

Implementation Method 1

improve heat transfer from a heat generating portion of the terminal fitting to the temperature sensor

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a thermistor (temperature sensor) is mounted to a terminal fitting attached to an end portion of the electric wire, and a temperature of the terminal fitting is detected

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3863123B1connector

Publication Date: 2023.04.05 YAZAKI CORP

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AI summary

A connector includes a terminal fitting connected to an end of an electric wire, a housing including a terminal accommodating chamber configured to accommodate the terminal fitting, a temperature sensor connected to an end of a detection line and configured to be attached to the terminal fitting, and a heat retaining cover. The heat retaining cover is configured to be attached to the housing such that the heat retaining cover covers a rear end portion of the housing and to retain heat inside the terminal accommodating chamber, the heat retaining cover having an electric wire guiding out portion through which the electric wire and the detection line drawn out from the terminal accommodating chamber are to be inserted.