Secondary Battery Internal Short Circuit Test Design

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Solution Overview

Problem

Existing secondary batteries face difficulties in accurately testing internal short-circuits between a positive electrode, lithium precipitate, and a negative electrode, or between a current collector and a negative electrode, due to incomplete charging and uneven lithium precipitate generation, making it challenging to perform the test in a desired direction.

Innovation Solution

A secondary battery design with a main first electrode and a second electrode, separated by a main separator with a through-hole, and an auxiliary electrode and separator that can be detachably attached to facilitate controlled short-circuit testing. The design includes a main first current collector with a non-coating surface for the auxiliary electrode attachment and a thinner coating layer on the second electrode to ensure uniform lithium precipitate generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coating layer is applied to the entire surface of the positive electrode current collector, then the electrode structure is complete and protective, but it prevents accurate testing of internal short circuits between the current collector and negative electrode

Engineering Contradiction:

Improveelectrode structure integrityVSAvoidinternal short circuit detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The positive electrode current collector surface is divided into a coated region and an uncoated region. The uncoated region serves as a test area where the current collector can directly contact the negative electrode to simulate internal short circuit conditions, while the coated region maintains normal protective function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the positive electrode current collector have different properties: the majority surface has a protective coating layer for normal operation, while a specific local area remains uncoated to enable short circuit testing. This local differentiation allows both protective function and testing capability to coexist.

Inventive Principle:

Principle #3Local quality

2Device complexity

If lithium precipitate is generated only partially on the negative electrode, then the battery structure is simpler, but it makes it difficult to perform comprehensive short circuit testing in the desired direction

Engineering Contradiction:

Improvebattery structure simplicityVSAvoidshort circuit test directional control

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The negative electrode is pre-treated to generate lithium precipitate on its entire surface before assembly. This preliminary action ensures that when the positive electrode current collector contacts the negative electrode during testing, the short circuit occurs in the desired direction with consistent lithium precipitate distribution.

Inventive Principle:

Principle #10Preliminary action

3Device complexity

If the negative electrode is not fully charged due to short circuit, then the test setup is simpler, but it makes it difficult to smoothly perform the charging test

Engineering Contradiction:

Improvetest setup simplicityVSAvoidcharging test smoothness

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The battery system transitions from a static short circuit condition to a dynamic charging process. By controlling the charging process and monitoring voltage changes, the system can detect short circuits while maintaining the ability to complete charging cycles, enabling smooth operation of the charging test.

Inventive Principle:

Principle #15Dynamics

4Ease of manufacture

If auxiliary components are permanently fixed in the battery structure, then the manufacturing process is simpler, but it reduces the ability to perform controlled short circuit testing

Engineering Contradiction:

Improveassembly process simplicityVSAvoidshort circuit testing control

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The auxiliary separator is designed to be movable rather than fixed. It can be positioned to block or open the through-hole in the main separator, enabling dynamic control of the short circuit condition. This movability allows the same structure to serve both normal operation and testing purposes.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The auxiliary separator acts as an intermediary component that mediates between the main separator and the electrodes. By positioning this intermediate layer, the system can control whether the positive electrode current collector contacts the negative electrode, enabling controlled short circuit testing.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables precise and controlled testing of internal short-circuits by allowing detachable attachment and detachment of auxiliary components, ensuring consistent lithium precipitate formation and accurate short-circuit detection.

Implementation Method 1

an auxiliary separator detachably attached to the main separator to block or open the through-hole

Methodology Applied

Scientific EffectPhysical barrier blocking:

Implementation Method 2

an auxiliary first electrode detachably attached to the first non-coating surface and configured to connect the first non-coating surface of the main first current collector to the second electrode so that internal short circuit between the first non-coating surface and the second electrode occurs through the opened through-hole

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

a main separator disposed between the main first electrode and the second electrode and having a through-hole at a position corresponding to the first non-coating surface

Methodology Applied

Scientific EffectPhysical separation:

Data Source

PatentEP4645520A1Secondary battery for testing internal short circuit and manufacturing method and testing method therefor

Publication Date: 2025.11.05 LG ENERGY SOLUTION LTD

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AI summary

The present invention relates to a secondary battery for an internal short-circuit test, and the secondary battery for the internal short-circuit test includes: an electrode assembly; and a pouch configured to accommodate the electrode assembly, wherein the electrode assembly includes: a main first electrode constituted by a main first current collector and a main first coating layer applied to a remaining surface except for a first non-coating surface that is partitioned on the main first current collector; a second electrode constituted by a second current collector and a second coating layer applied to a surface of the second current collector; a main separator disposed between the main first electrode and the second electrode and having a through-hole at a position corresponding to the first non-coating surface; an auxiliary separator detachably attached to the main separator to block or open the through-hole; and an auxiliary first electrode detachably attached to the first non-coating surface and configured to connect the first non-coating surface of the main first current collector to the second electrode so that internal short circuit between the first non-coating surface and the second electrode occurs through the opened through-hole when being detached.