Lithium Battery Pillared Current Collector for Stress Reduction

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Solution Overview

Problem

Conventional solid state Li-based batteries with high-aspect ratio structures face challenges in minimizing electrochemically inactive current collectors while maintaining rate performance, leading to stress and reduced cycle life due to non-economical production methods and design limitations.

Innovation Solution

A Lithium battery design featuring elongate, aligned pillars with a high aspect ratio current collector structure, where adjacent pillars are merged to form a topstrate current collector in the interspace, allowing for a conformal multilayer coating and optimized charge collection, reducing the relative weight of current collectors and minimizing stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If high-aspect ratio structures are used to increase charge capacity, then charge collecting capacity is improved, but stress and reduced cycle life occur due to solid state electrolyte inducing stress

Engineering Contradiction:
Improvecharge capacityVSAvoidcycle life
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent changes the physical state of the electrolyte from solid to liquid, fundamentally altering the mechanical properties of the battery components. This parameter change eliminates the stress induction problem inherent in solid state electrolytes while maintaining the high-aspect ratio structure's charge capacity benefits. The liquid electrolyte accommodates the pillar structure's expansion and contraction during charging cycles without inducing damaging stress.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure combining liquid electrolyte with the high-aspect ratio pillar architecture. This composite approach allows the system to simultaneously achieve high charge capacity through the pillar structure and high reliability through the stress-absorbing liquid electrolyte medium, resolving the contradiction between quantity and reliability.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If conventional production methods are used for high-aspect ratio structures, then manufacturing is achieved, but production is non-economical and time-consuming

Engineering Contradiction:
Improvestructure formationVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces conventional mechanical microfabrication methods with a chemical self-assembly approach. The pillar structures form spontaneously through controlled chemical processes rather than through time-consuming mechanical machining or lithography, dramatically increasing production speed while maintaining manufacturing precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements preliminary action by pre-forming the pillar structures through a rapid chemical process before battery assembly. This preliminary formation of the high-aspect ratio structure enables subsequent economical manufacturing steps and avoids time-consuming post-assembly adjustments, thereby improving overall productivity.

Inventive Principle:
Principle #10Preliminary action

3Weight of moving object

If electrochemically inactive current collectors are minimized, then weight is reduced, but rate performance may be compromised

Engineering Contradiction:
Improvecurrent collector weightVSAvoidrate performance
Core Design Contradiction:
Weight of moving objectVSPower

Solution Approach 1:

The patent transitions from a planar two-dimensional current collector to a three-dimensional high-aspect ratio pillar structure. This dimensional change dramatically increases the effective surface area for charge collection while minimizing the volume and weight of the current collector material. The vertical pillars provide extensive electrochemically active surface area without proportionally increasing the amount of inactive current collector material.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs a porous-like pillar structure that maximizes surface area to volume ratio. The high-aspect ratio pillars create a three-dimensional network with substantial surface area for electrochemical reactions while minimizing the material volume. This porous architecture ensures adequate rate performance by providing numerous reaction sites while keeping the current collector weight low.

Inventive Principle:
Principle #31Porous materials

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

This design enhances charge collecting capacity, maintains rate performance, and increases energy density by reducing the weight and volume of current collectors, while allowing for cost-effective manufacturing and flexible integration in devices.

Implementation Method 1

a solid state electrolyte layer provided on the first electrode; and a second electrode layer wherein charge exchange between a negative electrode material and a positive electrode material

Methodology Applied
Scientific EffectIon transport: Ion Exchange

Implementation Method 2

an electronic device having a current collector formed by a metal substrate having a face forming a high-aspect ratio structure of pillars

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3391442B1Lithium battery current collector comprising conductive pillared structures on a substrate
Publication Date: 2022.04.20 NEDERLANDSE ORG VOOR TOEGEPAST NATUURWETENSCHAPPELIJK ONDERZOEK TNO
  • EP3391442B1 patent drawingFigure 1a~1b
  • EP3391442B1 patent drawingFigure 2~3
  • EP3391442B1 patent drawingFigure 4~5

AI summary

A method of manufacturing a Lithium battery with a substrate current collector formed of pillars on a substrate face, wherein the method comprises: forming elongate and aligned structures forming electrically conductive pillars on the substrate face with upstanding pillar walls; wherein the pillars are formed with a first electrode, a solid state electrolyte layer provided on the first electrode; and a second electrode layer, wherein the pillars are dimensioned in such a way that adjacent pillars are merged and a topstrate current collector is formed of complementary interspace structures between the merged pillars.