Battery Pack Impact Protection via Piezoelectric Sensor and Alarm Circuit

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Solution Overview

Problem

Conventional battery pack protection circuits lack the ability to detect and respond to physical impacts, which can lead to ignition or explosion of cells.

Innovation Solution

An apparatus with a sensor to detect external physical impacts, generating alarm signals through a zener diode and alarm circuit, including multicolored LEDs, and interrupting electricity supply to prevent damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional protection circuit is used to monitor voltage, current, and temperature, then overcharge, over-discharge, over-current, and short-circuiting are prevented, but the battery pack remains vulnerable to physical impact causing cell ignition or explosion

Engineering Contradiction:
Improveprotection capabilityVSAvoidphysical impact vulnerability
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protection system is segmented into multiple independent detection modules: voltage detection, current detection, temperature detection (via thermistor), and impact detection (via piezoelectric sensor). Each module independently monitors a specific parameter and triggers appropriate protection measures, allowing comprehensive protection without requiring a single complex system

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A piezoelectric sensor acts as an intermediary element that converts mechanical impact forces into electrical signals. This sensor is positioned between the external environment and the battery cells, detecting physical impact and transmitting the converted electrical signal to the protection circuit, which then triggers protective actions to prevent cell damage

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If no impact detection function is added to the battery pack, then the circuit remains simple and cost-effective, but the battery pack safety is compromised under physical impact conditions

Engineering Contradiction:
Improvecircuit simplicityVSAvoidimpact safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mechanical impact detection system is replaced with an electrical detection system. Instead of using complex mechanical switches or physical breakers that would increase device complexity, a piezoelectric sensor converts mechanical impact directly into electrical signals that can be processed by the existing electronic protection circuit, maintaining circuit simplicity while enabling impact detection

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

Solution Approach 2:

The protection circuit is designed with multi-functionality by integrating multiple detection capabilities (voltage, current, temperature, and impact) into a single unified system. The same protection circuit architecture handles all four parameters, with each detection module feeding into the central protection logic, allowing the system to perform multiple protection functions without proportionally increasing 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

Effectively protects battery packs from physical impacts by visually indicating impact intensity and preventing electrical supply to prevent cell ignition or explosion.

Implementation Method 1

a sensor for detecting external physical impact so as to output a voltage signal; the sensor preferably includes at least one of a piezoelectric sensor

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a zener diode to which electricity is applied when the sensor outputs the voltage signal which is larger than a predetermined value of voltage

Methodology Applied
Scientific EffectZener breakdown: Avalanche Breakdown

Implementation Method 3

The alarm circuit includes multicolored light emitting diodes to emit red, yellow, and green lights according to the voltage output from the sensor

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP1878101B1Apparatus and method of protecting battery packs
Publication Date: 2014.12.10 LG CHEM LTD
  • EP1878101B1 patent drawingFigure 1
  • EP1878101B1 patent drawingFigure 2
  • EP1878101B1 patent drawingFigure 3

AI summary

Disclosed are an apparatus and a method for protecting a battery pack. The apparatus includes: a sensor for detecting external physical impact so as to output a voltage signal; a first protection circuit for receiving the voltage signal output from the sensor; a gauging IC for determining whether the voltage received from the first protection circuit is larger than a predetermined value, so as to output the voltage signal to either the first protection circuit or a second protection circuit; the second protection circuit for receiving the voltage signal from the gauging IC; and an alarm circuit connected to the first and second protection circuits so as to receive the voltage signal from the first and second protection circuits and raise an alarm signal.