Battery Pack Current Detection Abnormality Diagnosis

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Solution Overview

Problem

Existing electrical device systems face challenges in detecting abnormality in current detecting units without increasing component count, leading to potential size and cost issues, as they require multiple detection circuits to determine normal operation.

Innovation Solution

The system employs a battery state detecting unit to estimate changes in battery voltage and temperature based on current, using a determining unit to calculate actual changes and detect abnormality, allowing for normal operation determination using existing voltage and temperature detection circuits, thereby preventing erroneous detection and reducing component count.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two systems of detection circuits are provided to determine abnormality of the current detecting unit, then abnormality detection capability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improveabnormality detection capabilityVSAvoidnumber of detection circuits
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The current detecting unit performs self-diagnosis by comparing its own detection results with reference values stored in the determination unit. The system uses the battery current detection result to determine whether the current detecting unit is abnormal, enabling self-service abnormality detection without requiring additional independent detection circuits.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The determination unit acts as an intermediary that stores reference values and compares them with actual detection results. This intermediary component enables abnormality detection functionality without requiring duplicate detection circuits, as it mediates between the single detection circuit and the abnormality determination process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If two systems of detection circuits are provided to determine abnormality of the current detecting unit, then abnormality detection capability is improved, but manufacturing cost increases

Engineering Contradiction:
Improveabnormality detection capabilityVSAvoidcomponent cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The determination unit serves multiple functions: it stores reference values, compares detection results with reference values, and determines abnormality status. This multi-functional design eliminates the need for separate abnormality detection circuits, reducing component count and manufacturing cost while maintaining abnormality detection capability.

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

Solution Approach 2:

The current detecting unit performs self-diagnosis using the determination unit, eliminating the need for additional dedicated abnormality detection circuits. This self-service approach reduces component requirements and manufacturing cost while maintaining reliable abnormality detection.

Inventive Principle:
Principle #25Self-service

3Reliability

If two systems of detection circuits are provided to determine abnormality of the current detecting unit, then abnormality detection capability is improved, but battery pack size increases

Engineering Contradiction:
Improveabnormality detection capabilityVSAvoidbattery pack size
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The abnormality detection functionality is merged into the existing control unit structure. The determination unit combines reference value storage, comparison logic, and abnormality determination functions within the existing control architecture, eliminating the need for separate physical detection circuits and reducing battery pack size.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The determination unit performs multiple functions including storing reference values, comparing detection results, and determining abnormality status. This multi-functional design consolidates what would otherwise require separate circuits into a single integrated unit, reducing the overall battery pack size.

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

Data Source

PatentEP2787362B1Electrical device system and battery pack
Publication Date: 2017.06.07 MAKITA CORP
  • EP2787362B1 patent drawingFigure 1
  • EP2787362B1 patent drawingFigure 2
  • EP2787362B1 patent drawingFigure 3

AI summary

An electrical device system having a battery pack (2), an electrical device (50), and a charging device (80), includes: a current detecting unit (24, 26) that detects a battery current flowing through the battery (10) during a charge to or a discharge from the battery; a battery state detecting unit (20, 22) that detects at least one of a battery voltage and a temperature of a heat generating unit; and a determining unit (40, 48) that estimates an amount of change in at least one of the battery voltage and the temperature of the heat generating unit, based on the battery current, and calculates an amount of actual change in at least one of the battery voltage and the temperature of the heat generating unit, wherein the determining unit determines that the current detecting unit is abnormal, when the difference between the calculated amount of actual change and the estimated amount of change is a default value or more.