Power Electronics Module Safety Mechanism for Electric Vehicle Maintenance

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Solution Overview

Problem

Maintenance operators face electrical risks when working on electric powertrains of hybrid or electric vehicles due to the risk of omitting voltage absence checks, as capacitors often remain energized, and existing solutions do not adequately protect against electrical shocks during discharge.

Innovation Solution

A power electronics module with a casing that has removable fixing means, where deactivating the blocking mechanism activates a discharge circuit for capacitors, ensuring capacitors are discharged before access is possible, using a plate with screw openings and a spring blade circuit for detection and activation of the discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cover is made easily accessible with removable fastening means, then maintenance operation ease is improved, but electrical safety deteriorates as operators can access live components without proper discharge

Engineering Contradiction:
Improvemaintenance operation easeVSAvoidelectrical shock risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The discharge circuit is activated automatically when the cover is removed, discharging capacitors before the operator can access live components. This preliminary discharge action eliminates the electrical shock risk while maintaining easy access to components for maintenance operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A safety device acts as an intermediary between the cover removal action and the live components. The safety device includes a discharge circuit that automatically discharges capacitors when the cover is removed, serving as a protective mediator that prevents direct exposure to charged capacitors while allowing maintenance access.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a discharge circuit is added to protect operators, then electrical safety is improved, but device complexity increases

Engineering Contradiction:
Improveelectrical shock riskVSAvoidmodule complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The discharge circuit is merged with the existing cover fastening mechanism. The safety device uses the same mechanical action of removing the cover to both access components and trigger the discharge circuit, combining the access function and safety function into a single integrated system rather than adding separate complex controls.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system automatically discharges capacitors when the cover is removed, without requiring manual intervention or additional controls from the operator. The mechanical removal of the cover self-triggers the discharge circuit through the safety device, making the system self-protecting and eliminating the need for complex external safety systems.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If the discharge time is extended to ensure complete discharge, then safety is improved, but maintenance time increases

Engineering Contradiction:
Improvedischarge completenessVSAvoidmaintenance time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The discharge circuit parameters (resistance, capacitance values) are optimized to achieve sufficient discharge (reducing voltage to safe levels) within a short time frame that does not significantly impact maintenance operations. This parameter optimization ensures both safety and operational efficiency without requiring extended wait times.

Inventive Principle:
Principle #35Parameter changes

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

Significantly reduces the risk of electric shock by ensuring capacitors are discharged before the operator can access the live element, even if the voltage absence check is omitted, while being simple and cost-effective to produce and integrate with existing discharge systems.

Implementation Method 1

said blocking means comprise a pin bearing on a spring-loaded strip closing an electrical circuit for detecting the deactivation of said blocking means

Methodology Applied
Scientific EffectSpring mechanism: Spring

Implementation Method 2

capable of activating, upon opening said electrical detection circuit, said discharge circuit

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3475117B1Electronic module for power safety at maintenance
Publication Date: 2020.03.04 RENAULT SA
  • EP3475117B1 patent drawingFigure 1
  • EP3475117B1 patent drawingFigure 2

AI summary

The invention relates to a power electronics module (MOD) of a hybrid or electric vehicle electric traction system, comprising a casing (CAR) housing an element that is live when the said system is in operation, the said element being accessible via a cover (COU) of the said casing (CAR), the said cover (COU) being fixed to the said casing (CAR) by removable fixing means (MF), characterized in that it comprises means (O1, O2) blocking the removal of the said fixing means (MF), the said blocking means (O1, O2) being connected to a safety device able to activate a discharge circuit which discharges the said live element when the said blocking means (O1, O2) are deactivated.