Battery Short-Circuit Test Switching for Chatter-Free Waveforms

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Solution Overview

Problem

The existing external short circuit test for lithium ion batteries using mechanical contact relays suffers from a chattering phenomenon, which distorts the battery current waveform and hinders accurate safety testing.

Innovation Solution

A battery safety test device and method that incorporates an electronic switching element in conjunction with a mechanical switch element, where the electronic switch turns on after the mechanical switch, to eliminate chattering and ensure accurate measurement of battery current waveforms during external short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mechanical contact relay is used to configure an external short circuit test circuit, then the circuit can be switched on and off, but chattering phenomenon occurs during contact connection which distorts the battery current waveform

Engineering Contradiction:

Improvecircuit switching capabilityVSAvoidbattery current waveform measurement accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical contact relay with an electronic switch element (such as MOSFET or IGBT) that is controlled by a gate circuit. This substitution eliminates the mechanical contact and associated chattering phenomenon, thereby removing the distortion in battery current waveform measurements while maintaining the circuit switching functionality required for external short circuit testing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If a mechanical contact relay is used for external short circuit testing, then the test circuit can be configured, but the reaction speed to the circuit is slow when opening and closing the relay

Engineering Contradiction:

Improvecircuit switching functionVSAvoidrelay response speed

Core Design Contradiction:

Ease of operationVSSpeed

Solution Approach 1:

The patent substitutes the mechanical relay with an electronic switch element controlled by a gate circuit. Electronic switches respond significantly faster than mechanical relays because they rely on electron flow rather than physical contact movement. This eliminates the slow response time inherent in mechanical systems while preserving the circuit switching capability needed for safety testing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If an electronic switch element is added after the mechanical switch element, then the chattering phenomenon is eliminated, but the device complexity increases

Engineering Contradiction:

Improvecurrent waveform measurement accuracyVSAvoidswitching circuit structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical switch element with an electronic switch element (MOSFET or IGBT) that is controlled by a gate circuit. Although this introduces an additional control component, it eliminates the need for mechanical contacts and their associated chattering problems. The electronic switching mechanism provides cleaner signal transitions and more precise control, justifying the slight increase in circuit complexity through significant improvements in measurement accuracy.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution effectively eliminates the chattering phenomenon, allowing for precise analysis and accurate measurement of battery current waveforms, thereby enhancing the reliability of battery safety tests.

Implementation Method 1

Since the mechanical contact relay is a physical switch using a magnetic, there is a disadvantage that the reaction speed to the circuit is slow when opening and closing the mechanical contact relay.

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

A battery safety test device includes: an electronic switching element; a mechanical switch element having a first end connected to either a battery positive electrode or battery negative electrode and a second end connected to the electronic switching element

Methodology Applied

Scientific EffectSemiconductor switching:

Data Source

PatentUS12206077B2Battery safety test device and method

Publication Date: 2025.01.21 LG ENERGY SOLUTION LTD

AI summary

The present invention provides a battery safety test device includes: a mechanical switch element having one end connected to either a battery positive or negative electrode and the other end connected to an electronic switching element; the electronic switching element having one end connected to the mechanical switch element and the other end connected to the other of the battery positive or negative electrode; a voltage sensor for measuring a voltage of the battery after the mechanical switch element and the electronic switching element are turned on; and a current sensor for measuring a current of the battery after the mechanical switch element and the electronic switching element are turned on.