Abnormality Diagnostic Device

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Solution Overview

Problem

Existing abnormality diagnostic devices for battery packs often incorrectly determine breaks in electrical connections due to malfunctioning switch components, leading to false positives.

Innovation Solution

The proposed solution involves an abnormality diagnostic device with cell voltage detecting circuits, discharging circuits, switch drive circuits, and diagnostic voltage detecting circuits, which perform specific diagnostic operations to differentiate between breaks in electrical connections and switch malfunctions by analyzing voltage readings during alternate and full switch activations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional diagnostic devices use switch components to short-circuit detection terminals for diagnosing electrical connection breaks, then the diagnostic function can be performed, but false positives occur when the switch components themselves malfunction

Engineering Contradiction:
Improvediagnostic accuracyVSAvoidfalse positives from switch malfunction
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces a diode as an intermediary component between the switch and the detection terminal. This diode acts as a protective element that prevents switch malfunctions from causing false diagnostic readings. The diode's unidirectional conductivity property allows it to block erroneous signals while permitting valid diagnostic signals to pass through, thereby eliminating false positives without compromising the diagnostic function.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies beforehand cushioning by pre-installing protective diodes in the circuit path before potential switch failures can occur. These diodes are positioned to cushion or absorb the harmful effects of switch malfunctions before they can reach the detection terminals, preventing false diagnostic results while maintaining system reliability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Measurement precision

If multiple diagnostic operations are performed to differentiate between connection breaks and switch malfunctions, then diagnostic accuracy improves, but the complexity of the diagnostic procedure increases

Engineering Contradiction:
Improveabnormality detection accuracyVSAvoiddiagnostic procedure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the diagnostic procedure into distinct operational phases: a first diagnostic operation that identifies potential abnormalities, and a second diagnostic operation that confirms and categorizes the specific type of abnormality. This segmentation allows the system to methodically differentiate between connection breaks and switch malfunctions through structured voltage measurements at different stages, improving accuracy while maintaining procedural clarity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamic diagnostic operations where the switching elements are actively controlled to change states between different measurement phases. The system dynamically adjusts the configuration of switching elements during the diagnostic process, performing voltage measurements under different switching conditions to distinguish between various types of abnormalities based on how the circuit responds to changing states.

Inventive Principle:
Principle #15Dynamics

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 approach accurately identifies electrical connection breaks and switch abnormalities, reducing false positives and improving diagnostic accuracy in battery pack diagnostics.

Implementation Method 1

a plurality of cell voltage detecting circuits with each of the cell voltage detecting circuits being connected in parallel to a corresponding one of the cells of the battery pack to detect a voltage of the corresponding one of the cells

Methodology Applied
Scientific EffectVoltage detection: Electric Field

Implementation Method 2

a plurality of discharging circuits with each of the discharging circuits being connected in parallel to a corresponding one of the cells to selectively discharge an electric power of the corresponding one of the cells, each of the discharging circuits including a switch and a resistor that are connected in series

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a plurality of diagnostic voltage detecting circuits with each of the diagnostic voltage detecting circuits being electrically connected to a corresponding one of the discharging circuits to detect a voltage across the corresponding one of the discharging circuits

Methodology Applied
Scientific EffectVoltage measurement: Electric Field

Data Source

PatentEP1936777B1Abnormality Diagnostic Device
Publication Date: 2017.11.01 NISSAN MOTOR CO LTD
  • EP1936777B1 patent drawingFigure 1
  • EP1936777B1 patent drawingFigure 2
  • EP1936777B1 patent drawingFigure 3

AI summary

An abnormality diagnostic device is configured to diagnose an abnormality in a battery pack having a plurality of cells connected in series. Each of a plurality of diagnostic voltage detecting circuits is configured to detect one of a voltage across a corresponding one of discharging circuits. An abnormality diagnostic control section is configured to perform a first diagnostic operation in which the switches corresponding to alternate ones of the cells are turned on and a second diagnostic operation in which all of the switches are turned on, and to determine whether a break exists in an electrical connection or an abnormality exists in one of the switches based on the voltages detected by the diagnostic voltage detecting circuits during the first diagnostic operation and the voltages detected by the diagnostic voltage detecting circuits during the second diagnostic operation.