Relay Diagnosis Circuit for Simultaneous Main-Relay Detection

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Solution Overview

Problem

Conventional relay diagnosing devices are unable to simultaneously diagnose the state of both positive and negative main relays in a parallel battery pack system, necessitating separate diagnosing sequences for each relay.

Innovation Solution

A relay diagnosing apparatus and method using a resistor dividing circuit with a common mode voltage differential amplifier to determine relay states by comparing input voltages through a resistor dividing circuit, allowing simultaneous diagnosis of both main relays.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional relay diagnosing devices are used in parallel battery pack systems, then separate diagnosing sequences are required for each relay, but this increases diagnosing time and reduces productivity

Engineering Contradiction:
Improverelay diagnosing efficiencyVSAvoiddiagnosing time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent combines the diagnosis of multiple relays (positive main relay and negative main relay) into a single unified diagnosing sequence. The resistor dividing circuit merges the diagnostic paths of multiple relays, allowing simultaneous measurement and evaluation of all relays through one diagnostic process, thereby eliminating the need for separate diagnosing sequences and improving productivity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The resistor dividing circuit serves multiple functions: it divides voltages for multiple relay diagnoses, provides common reference voltages, and enables simultaneous monitoring of multiple relays. This multi-functional design allows a single diagnostic device to handle all relay diagnoses in parallel battery pack systems, reducing both time and complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If separate diagnosing sequences are used for each relay, then each relay can be diagnosed individually, but the diagnosing process becomes more complex and less efficient

Engineering Contradiction:
Improverelay state detection accuracyVSAvoiddiagnosing process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The resistor dividing circuit acts as an intermediary that simplifies the diagnostic process. It automatically divides and distributes reference voltages to multiple diagnostic points, eliminating the need for complex manual voltage distribution and switching sequences. This intermediary structure maintains measurement precision while significantly reducing process complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If conventional diagnostic methods are used, then individual relay diagnosis is possible, but simultaneous diagnosis of multiple relays is not achievable

Engineering Contradiction:
Improvediagnosis throughputVSAvoiddiagnosis operation simplicity
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The resistor dividing circuit segments the voltage reference distribution into distinct, independent paths for each relay, while maintaining a unified diagnostic structure. This segmentation allows simultaneous independent measurement of multiple relays without interference, enabling both high productivity and operational simplicity through modular voltage distribution.

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

Enables the diagnosis of relay stuck-closed states in all situations using a simpler circuit and method, improving efficiency in parallel battery pack systems.

Implementation Method 1

a relay diagnosis voltage generating apparatus that includes a resistor dividing circuit including a first resistance element and a second resistance element connected in series between both ends of the main relay; and a voltage divider that generates the relay diagnosis voltage based on a voltage applied to the main relay and a resistance ratio between the first resistance element and the second resistance element

Methodology Applied
Scientific EffectResistor dividing circuit: Electrical Resistance

Data Source

PatentEP4270025B1Relay diagnosis device and relay diagnosis method
Publication Date: 2025.10.29 LG ENERGY SOLUTION LTD
  • EP4270025B1 patent drawingFigure 1
  • EP4270025B1 patent drawingFigure 2
  • EP4270025B1 patent drawingFigure 3

AI summary

An apparatus for diagnosing a main relay that controls connection between a battery pack and a load may comprise a resistor dividing circuit including a plurality of resistors, wherein the resistor dividing circuit is connected between a first main relay connected to a positive terminal of the battery pack and the load and between one end of a second main relay connected to the negative terminal of the battery pack and the other end of the second main relay, and a diagnosing module connected to the resistor dividing circuit and a voltage source and configured to output a relay diagnosis voltage to be used for diagnosing the first main relay and the second main relay.