Ground Leakage Detector for Electric Vehicle Charging Connector

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Solution Overview

Problem

Existing ground leakage detectors in electric vehicles cannot detect ground leakage before the vehicle's systems are activated, limiting their functionality.

Innovation Solution

A ground leakage detector that connects to the electric vehicle's charging connector, allowing for detection of ground leakage on both the positive and negative sides of the battery, regardless of the system's activation status, using a connector connection section that can be electrically connected to the charging connector, and utilizing in-vehicle relays to control the connection between the battery and charging connector for efficient power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ground leakage detector is activated only after the vehicle's systems are activated, then the detection can utilize the system's power supply, but the detection cannot be performed before system activation limiting safety checks

Engineering Contradiction:
Improveground leakage detection capabilityVSAvoiddetection availability across different system states
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The detector dynamically adapts its operation mode based on system state. In standby mode, it performs detection using stored battery power without activating other systems. In operation mode, it detects ground leakage utilizing the active power supply, thus resolving the contradiction between detection capability and system activation requirements

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The detector is designed to perform ground leakage detection before the vehicle's main systems are activated, using the stored electric power in the battery. This preliminary detection ensures safety before system activation, addressing the limitation of existing detectors that can only operate after systems are on

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the detector continuously monitors ground leakage using stored battery power, then detection is always available, but power consumption increases reducing efficiency

Engineering Contradiction:
Improvecontinuous ground leakage detectionVSAvoidbattery power consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The detector performs ground leakage detection periodically or at specific events (charging connection, system activation) rather than continuously. This periodic operation maintains detection reliability while minimizing battery power consumption during standby periods

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The detector ensures continuous detection capability by switching between two power sources: stored battery power for standby detection and active power supply for operation mode detection. This continuity of useful action maintains safety monitoring without excessive power consumption from continuous battery drainage

Inventive Principle:
Principle #20Continuity of useful action

3Measurement precision

If the detector requires system activation to perform detection, then power supply is stable, but detection cannot identify pre-existing ground leakage issues

Engineering Contradiction:
Improveground leakage detection accuracyVSAvoidtime to detect ground leakage
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The detector is configured to perform ground leakage detection immediately upon charging connector connection, before the vehicle's main systems are activated. This preliminary action detects pre-existing ground leakage issues that would be missed by post-activation detection alone

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The charging connector serves as an intermediary trigger that initiates detection independently of the main system activation. When the charging connector is connected, it provides a stable reference point for the detector to perform accurate ground leakage measurement without requiring the entire vehicle system to be active

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the detection of ground leakage before the vehicle's systems are activated, ensuring safety and efficiency by utilizing the stored electric power and reducing power consumption, while also allowing for self-diagnostic operations and automatic detection during charging.

Implementation Method 1

it can be detected whether or not there is a ground leakage from the battery unit to the vehicle body ground location based on the current flowing between the connector connection section and the contactor

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2801836B1Leak detector, and leak detection method for electric vehicle
Publication Date: 2019.07.10 KAWASAKI JUKOGYO KK
  • EP2801836B1 patent drawingFigure 1
  • EP2801836B1 patent drawingFigure 2
  • EP2801836B1 patent drawingFigure 3A

AI summary

A ground leakage detector (100) for detecting a ground leakage in an electric vehicle (1) including a battery (60), and a charging connector (49) which is electrically connectable to a terminal member formed at one end of an outside electric wire through which electric power is supplied from outside to the battery, includes a connector connection section (TP, TN, SW3A, SW3B) electrically connectable to the charging connector; a contactor (109) configured to contact a vehicle body ground location (4) in the electric vehicle; and a detecting circuit (Rp, Rn, 112) for detecting whether or not there is a ground leakage from the battery to the vehicle body ground location, based on a current flowing between the connector connection section and the contactor.