Battery Pack Liquid Leak Detection via Foam Resistance

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Solution Overview

Problem

Existing battery packs lack an effective method to detect liquid leaks, which can lead to damage and safety issues.

Innovation Solution

A liquid leak detection system comprising electrically conductive wire grids, an open-cell foam layer, and a microprocessor that compares resistance signals to detect liquid migration, triggering alerts when a threshold is met.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a liquid leak detection system is added to the battery pack, then the safety and reliability are improved, but the device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs an open-cell foam layer as a porous material that allows liquid to migrate through it via capillary action. This porous structure enables the detection system to sense liquid leaks without requiring complex sealing or containment mechanisms, thereby improving safety while maintaining relatively simple device architecture.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The patent replaces complex mechanical leak detection mechanisms with an electrical resistance measurement system. Instead of using mechanical sensors or switches that would increase device complexity, the system uses changes in electrical resistance caused by liquid migration through the foam layer to detect leaks, simplifying the overall device structure while enhancing reliability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If an open-cell foam layer is used to allow liquid migration, then the liquid detection capability is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveliquid detection capabilityVSAvoidfoam layer thickness control
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The patent specifies a predetermined thickness range for the open-cell foam layer (0.5mm to 5mm) that optimizes liquid migration while accounting for manufacturing tolerances. By defining this parameter range rather than requiring a single precise value, the system achieves reliable liquid detection capability while remaining compatible with standard manufacturing precision capabilities.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If multiple wire grids and foam layers are used for detection, then the measurement precision is improved, but the device complexity increases

Engineering Contradiction:
Improveresistance measurement accuracyVSAvoiddetection system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The detection system is segmented into distinct functional layers: wire grids for electrical contact, open-cell foam for liquid migration, and insulating mats for electrical isolation. This segmentation allows each component to perform its specific function efficiently, improving measurement precision while keeping the overall structure organized and manageable rather than truly complex.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The wire grids serve multiple functions: they provide electrical contact for resistance measurement, structural support for the foam layer, and a pathway for liquid migration. This multi-functionality reduces the need for additional separate components, thereby improving measurement precision without proportionally increasing device complexity.

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

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

The system effectively detects liquid leaks by monitoring resistance changes, providing timely alerts and enhancing the safety and reliability of battery packs.

Implementation Method 1

The open-cell foam layer has a predetermined thickness to allow at least a portion of liquid contacting the open-cell foam layer to migrate from the first side to the second side

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

a resistance measuring device configured to output a first signal indicative of a resistance level between the first and second electrically conductive wire grids

Methodology Applied
Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentEP2506360B1Battery pack having liquid leak detection system
Publication Date: 2014.06.18 LG CHEM LTD
  • EP2506360B1 patent drawingFigure 1
  • EP2506360B1 patent drawingFigure 2
  • EP2506360B1 patent drawingFigure 3

AI summary

A battery pack and a liquid leak detection system are provided. The system includes first and second wire grids and an open-cell foam layer. The first and second wire grids are disposed on first and second sides, respectively, of the foam layer. The foam layer allows at least a portion of liquid contacting the foam layer to migrate from the first side to the second side. The system further includes an insulating mat disposed between the second wire grid and a tray. The system further includes a resistance measuring device that outputs a first signal indicative of a resistance level between the wire grids. The system further includes a microprocessor that compares an amplitude of the first signal to a threshold value, and outputs a second signal if the liquid is detected based on the comparison.