Battery Contactor Cycle Tracking for Replacement Timing

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Solution Overview

Problem

The existing contactors in electric vehicles experience fatigue due to cutoff and inrush currents, leading to potential welding in closed or open states, causing damage to loads and increasing replacement costs if timing is not optimally managed.

Innovation Solution

A method to determine contactor replacement timing by counting openings and closings based on operation voltage, using a control unit to manage the contactor's fatigue accumulation, and a battery system to implement this method.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contactor is replaced early to prevent welding, then reliability is improved, but replacement cost increases due to unnecessary replacements

Engineering Contradiction:
Improvecontactor reliabilityVSAvoidreplacement cost
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the parameter from fixed replacement intervals to dynamic replacement timing based on actual fatigue accumulation. By monitoring operation voltage and counting opening/closing cycles, the system determines replacement timing based on actual usage conditions rather than predetermined schedules, optimizing both reliability and cost efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control unit continuously monitors the operation voltage supplied to the contactor and counts the number of opening and closing operations. This feedback mechanism allows the system to track fatigue accumulation in real-time and determine the optimal replacement timing based on actual wear conditions, preventing both premature and delayed replacements

Inventive Principle:
Principle #23Feedback

2Loss of substance

If the contactor is replaced late to reduce costs, then replacement cost decreases, but welding occurs causing load damage

Engineering Contradiction:
Improvereplacement costVSAvoidcontactor reliability
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The system transitions from static replacement scheduling to dynamic timing based on accumulated fatigue. By continuously monitoring operation voltage and counting cycles, the replacement timing is adjusted according to actual usage patterns and wear accumulation, ensuring replacement occurs at the optimal moment before welding risk increases

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control unit performs preliminary monitoring and counting of contactor operations to predict fatigue accumulation before welding occurs. By tracking the number of opening/closing cycles and operation voltage in advance, the system can schedule replacement proactively at the optimal time, preventing welding while avoiding unnecessary early replacements

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If the contactor operates continuously without monitoring, then device complexity is reduced, but fatigue accumulation leads to welding

Engineering Contradiction:
Improvesystem complexityVSAvoidcontactor reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The control unit automatically monitors operation voltage and counts contactor opening/closing cycles without requiring external intervention. The system self-manages the fatigue tracking and determines replacement timing autonomously, providing a simple yet effective monitoring solution that prevents welding while maintaining operational simplicity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system implements a feedback loop where the control unit continuously monitors operation voltage supplied to the contactor and counts each opening and closing operation. This automatic feedback mechanism tracks fatigue accumulation in real-time and provides the basis for determining optimal replacement timing, preventing welding through simple monitoring

Inventive Principle:
Principle #23Feedback

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

Accurately predicts contactor replacement time, reducing additional costs and preventing welding by maintaining optimal timing for replacement.

Implementation Method 1

a coil unit that performs an electromagnet function when the operation voltage is supplied

Methodology Applied
Scientific EffectElectromagnet function: Electromagnet

Implementation Method 2

a plunger unit for releasing or contacting the moving contact unit from or to the first fixed contact unit and the second fixed contact unit by reciprocating in a straight line by the electromagnetic force of the coil unit

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP4071490B1Contactor management method and battery system providing the same method thereof
Publication Date: 2025.11.12 LG ENERGY SOLUTION LTD
  • EP4071490B1 patent drawingFigure 1
  • EP4071490B1 patent drawingFigure 2
  • EP4071490B1 patent drawingFigure 3

AI summary

Discussed is a contactor management method and a battery system to perform the method, wherein the battery system includes a contactor connected between a battery pack and an external device; a voltage measurer to measure a first operation voltage supplied to the contactor; and a controller to determine opening or closing of the contactor based on the first operation voltage measured from the voltage measurer, wherein the controller determines the contactor as open in an opened state when the first operation voltage is not supplied to the contactor, determines the contactor as closed in a closed state when the first operation voltage is supplied to the contactor, and counts each openings and closings of the contactor and determines a replacement time of the contactor based on a sum value of the counts exceeding a predetermined reference value.