Adiabatic Layer on Negative Electrode Tab for Battery Thermal Safety

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Solution Overview

Problem

Lithium secondary batteries face frequent overheating and explosion due to short circuits between electrode layers, primarily caused by heat generated at the electrode tabs, which melts the separator and leads to additional short circuits during overcharging or overdischarging.

Innovation Solution

Incorporating an adiabatic layer with a higher melting point than the separator, attached to the surface opposite the negative electrode tab, to interrupt heat transmission and prevent separator melting and subsequent short circuits, along with optional adiabatic layers on the positive electrode and insulation layers on the tabs to further manage heat and prevent direct contact with the separator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the separator is positioned between positive and negative electrode layers to prevent short circuits, then electrical insulation is improved, but the separator melts due to heat generated at electrode tabs during overcharging or overdischarging, causing additional short circuits

Engineering Contradiction:

Improveshort circuit preventionVSAvoidseparator melting temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

An adiabatic layer is introduced as an intermediary component between the electrode tab and the separator. This layer has higher thermal stability than the separator and acts as a heat barrier, preventing heat generated at the electrode tab from reaching and melting the separator, thus maintaining the separator's insulating function even under thermal stress

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The adiabatic layer is positioned in advance at the location where heat is generated (at the electrode tab) to cushion or block the heat transmission before it can reach the separator. This preventive measure ensures that even if overheating occurs during overcharging or overdischarging, the separator remains intact

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If electrode tabs are welded to non-coated areas of electrode collectors for electrical connection, then electrical conductivity is improved, but heat generated at the weld joints causes separator melting and short circuits

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidheat generation at tab

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The adiabatic layer serves as a thermal intermediary between the electrode tab (where heat is generated) and the separator. It blocks the harmful thermal effect while allowing the electrical connection at the tab to function normally, thus resolving the contradiction between maintaining electrical connectivity and preventing heat-induced damage

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the battery structure is simplified without additional protective layers, then device complexity is reduced, but safety against overheating and explosion is compromised

Engineering Contradiction:

Improvebattery structure complexityVSAvoidoverheating protection

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The adiabatic layer is implemented as a thin film or layer that can be integrated into the existing battery structure without significantly increasing complexity. This thin protective layer provides essential thermal protection while maintaining the overall simplicity of the battery design

Inventive Principle:

Principle #30Flexible shells and thin films

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 adiabatic layer effectively prevents heat-induced separator melting and short circuits, enhancing the safety and reliability of lithium secondary batteries by reducing the risk of overheating and explosion.

Implementation Method 1

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS9508973B2Secondary battery

Publication Date: 2016.11.29 SAMSUNG SDI CO LTD

AI summary

An electrode assembly for a secondary battery comprising an adiabatic layer attached to the negative electrode layer is disclosed. The electrode assembly comprises a positive electrode layer having a positive electrode collector, a positive electrode coating, and a non-coated area on the positive electrode collector. The negative electrode layer has a negative electrode collector, a negative electrode coating, and a non-coated area on the negative electrode collector. A separator insulates the positive and negative electrode layers. Positive and negative electrode tabs are attached to the non-coated areas of the positive and negative electrode collectors. The negative electrode layer has an adiabatic layer attached to the surface of a non-coated area of the negative electrode collector that is opposite the surface to which the negative electrode tab is attached. This construction improves battery stability and prevents short circuits caused either by heat generated during overcharging or by an internal short circuit.