Aluminum Alloy Cathode Current Collector to Resist Cracks in Thin Cells

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Solution Overview

Problem

Rechargeable lithium batteries face mechanical property degradation and safety issues due to crystal growth and crystallinity changes in thin aluminum positive electrode current collectors, leading to physical damage such as pin-holes and cracks during manufacturing.

Innovation Solution

A positive electrode current collector made of an aluminum alloy containing dispersed Cu and Al, with specific compositional ratios, is used to minimize mechanical property deterioration, even when thinned, thereby improving safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the Al positive electrode current collector is made into a thin film to increase energy density, then the energy density is improved, but the mechanical strength and safety deteriorate due to crystal growth and crystallinity changes

Engineering Contradiction:

Improveenergy densityVSAvoidtensile strength

Core Design Contradiction:

Quantity of substanceVSStrength

Solution Approach 1:

The patent applies composite materials by combining Al with Cu and Si to form an aluminum alloy current collector. The Cu and Si elements form dispersed aggregates within the Al matrix, creating a composite structure that prevents crystal growth while maintaining thin film properties. This composite approach resolves the contradiction by providing both the thinness needed for high energy density and the mechanical strength needed for safety.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical composition parameters of the current collector by introducing specific amounts of Cu (0.01-3 wt%) and Si (0.01-3 wt%) elements. This parameter change transforms the pure Al material into an aluminum alloy with enhanced properties, allowing the thin film to resist crystal growth and maintain tensile strength while achieving high energy density.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If the Al positive electrode current collector is made into a thin film, then the energy density is improved, but physical damage such as pin-holes and cracks occurs

Engineering Contradiction:

Improveenergy densityVSAvoidsafety

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The composite aluminum alloy structure with Cu and Si aggregates provides enhanced reliability by preventing physical damage. The dispersed Cu and Si particles act as barriers that inhibit crack propagation and prevent pin-hole formation, ensuring safety while maintaining the thin film configuration for high energy density.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The Cu and Si aggregates are incorporated beforehand into the Al matrix to provide preventive protection against crystal growth and physical damage. This prior cushioning approach ensures that the thin film current collector is pre-equipped with structural reinforcement that prevents pin-holes and cracks before they can occur during battery manufacturing and operation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Ease of manufacture

If heat and pressure are applied during manufacturing to form the battery, then the battery assembly is completed, but crystal growth occurs in the thin Al current collector

Engineering Contradiction:

Improvebattery assemblyVSAvoidcrystallinity

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent changes the compositional parameters by adding Cu and Si elements that fundamentally alter the thermal and pressure response of the current collector. These compositional changes enable the material to withstand manufacturing heat and pressure without undergoing harmful crystal growth, maintaining compositional stability while allowing complete battery assembly.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The Cu and Si aggregates are locally distributed within the Al matrix, creating regions of enhanced stability that specifically resist crystal growth during heat and pressure application. This local quality approach allows the current collector to maintain its crystalline structure integrity during manufacturing while still permitting complete battery assembly.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260024777A1Positive electrode current collectors for rechargeable lithium batteries, electrodes containing positive electrode current collectors, and rechargeable lithium batteries containing positive electrode current collectors

Publication Date: 2026.01.22 SAMSUNG SDI CO LTD

AI summary

The present disclosure relates to a positive electrode current collector for a rechargeable lithium battery, a positive electrode including the positive electrode current collector, and a rechargeable lithium battery including the positive electrode current collector. In particular, the present disclosure relates to a positive electrode current collector including an aluminum alloy current collector; and an aggregate including Cu and Al dispersed inside the aluminum alloy collector, wherein the aggregate includes Cu and Al which satisfy a certain mathematical relationship.