Negative Electrode with Polyethylene Functional Layer for Rapid Charging Safety

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Solution Overview

Problem

Rechargeable lithium batteries face challenges in achieving high-rate charge characteristics while ensuring thermal and physical safety, particularly during rapid charging, as they are prone to explosions due to internal short circuits and thermal runaway.

Innovation Solution

A negative electrode design featuring a crystalline carbonaceous material with a specific X-ray diffraction peak intensity ratio and a negative functional layer with flake-shaped polyethylene particles, which enhances safety by quickly shutting down the battery under abnormal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If high input and output are used for rapid charge, then charge time is reduced, but thermal safety deteriorates due to heat generation and risk of thermal runaway

Engineering Contradiction:

Improvecharge timeVSAvoidthermal safety

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-coating the negative active material layer with a functional layer containing flake-shaped polyethylene particles and inorganic particles before battery operation. This functional layer is prepared in advance to quickly shut down the battery under abnormal conditions, preventing thermal runaway during rapid charging operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by incorporating a functional layer with heat-resistant inorganic particles (such as aluminum oxide, aluminum hydroxide, magnesium hydroxide, or titanium oxide) and flake-shaped polyethylene particles. This layer acts as a protective barrier that cushions against thermal runaway and internal short circuits before they can cause catastrophic failure during rapid charging.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Power

If internal short circuit occurs, then electrical energy is released, but explosion risk increases

Engineering Contradiction:

Improveelectrical energy releaseVSAvoidexplosion risk

Core Design Contradiction:

PowerVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful effect of internal short circuits into a beneficial safety mechanism. The functional layer containing flake-shaped polyethylene particles is designed to quickly shut down the battery when abnormal conditions occur, transforming the potential harmful electrical energy release from internal short circuits into a controlled shutdown that prevents explosion.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If crystalline carbonaceous material with specific XRD ratio is used, then high-rate charge characteristics are improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improvehigh-rate charge characteristicsVSAvoidXRD peak intensity ratio control

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by specifying a precise range for the XRD peak intensity ratio l(002)/l(110) of the crystalline carbonaceous material (ranging from 30 to 110). This parameter control optimizes the crystalline structure to achieve excellent high-rate charge characteristics while maintaining feasible manufacturing precision through defined tolerances.

Inventive Principle:

Principle #35Parameter changes

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 design improves high-rate charge characteristics and thermal and physical safety by maintaining specific capacity and preventing heat generation, thus reducing the risk of explosions.

Implementation Method 1

the crystalline carbonaceous material has a ratio, l( 002 )/l( 110 ) of X-ray diffraction peak intensity at a (002) plane to X-ray diffraction peak intensity at a (110) plane ranging from 30 to 110 determined by using a CuKa ray

Methodology Applied

Scientific EffectX-ray diffraction: X-Ray

Implementation Method 2

the negative functional layer includes flake-shaped polyethylene particles... quickly shutting down the battery under abnormal conditions

Methodology Applied

Scientific EffectPhase change (melting): Melting

Data Source

PatentEP3734706B1Negative electrode for rechargeable lithium battery and rechargeable lithium battery comprising same

Publication Date: 2022.03.30 SAMSUNG SDI CO LTD

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AI summary

Disclosed is a negative electrode for a rechargeable lithium battery, including a negative current collector, a negative active material layer, and a negative functional layer which are sequentially laminated, the negative active material layer including a negative active material including a crystalline carbonaceous material, having a ratio, I(002)/I(110) of X-ray diffraction peak intensity at a (002) plane to X-ray diffraction peak intensity at a (110) plane ranging from 30 to 110, the negative functional layer comprises a flake-shaped polyethylene particle. The flake-shaped polyethylene particles have (i) a particle size of 1 µm to 8 µm, (ii) a thickness of 0.2 µm to 4 µm, and (iii) a ratio of a length of a long axis to a length of a short axis of 1 to 5.