Lithium-Ion Battery Electrode Auxiliary Channels

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Solution Overview

Problem

Conventional battery manufacturing methods struggle to optimize the ratio of active to non-active materials, leading to suboptimal performance and high costs, particularly when attempting to increase electrode thickness for higher capacitance surface loading, which results in reduced performance at high C rates and peak currents.

Innovation Solution

The method involves creating a matrix of auxiliary channels within the electrode layers of both the anode and cathode, aligned perpendicular to the current conductor, which improves the surface area and volume ratio of active to non-active materials, allowing for thicker electrodes to function effectively at high C rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If electrode thickness is increased to improve capacitance surface loading, then the ratio of active to non-active materials improves, but performance at high C rates deteriorates due to reduced lithium ion transport efficiency

Engineering Contradiction:
Improvecapacitance surface loadingVSAvoidperformance at high C rates
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The electrode layer is segmented into multiple functional zones by introducing auxiliary channels that divide the thick electrode into thinner effective layers. These channels create a multi-layered structure where lithium ion transport paths are shortened and distributed, allowing thick electrodes to maintain high C rate performance by effectively reducing the diffusion distance in each segment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Auxiliary channels are introduced into the electrode layer to create a porous structure that facilitates lithium ion transport. These channels provide additional pathways for ion diffusion, reducing the effective transport distance through thick electrodes and maintaining high conductivity even at increased electrode thickness, thereby improving both capacitance loading and C rate performance.

Inventive Principle:
Principle #31Porous materials

2Quantity of substance

If electrode thickness is increased to improve capacitance surface loading, then the amount of active material increases, but stress on the separator increases leading to potential failure

Engineering Contradiction:
Improveamount of active materialVSAvoidseparator stress resistance
Core Design Contradiction:
Quantity of substanceVSStrength

Solution Approach 1:

The auxiliary channels segment the thick electrode structure, distributing the mechanical stress from electrode expansion and contraction across multiple smaller zones rather than concentrating it on the separator. This segmentation reduces the peak stress on the separator while maintaining the total amount of active material, preventing separator failure even in thick electrodes.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If conventional manufacturing methods are used, then manufacturing simplicity is maintained, but the ratio of active to non-active materials cannot be optimized

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidratio of active to non-active materials
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The auxiliary channels are formed in the electrode layer before final assembly, allowing the porous structure to be pre-established in a controlled manner. This preliminary formation of the channel network enables subsequent filling with active material slurry, simplifying the manufacturing process while achieving optimized material ratios that would be difficult to obtain with conventional methods.

Inventive Principle:
Principle #10Preliminary action

4Quantity of substance

If thicker electrodes are used to increase capacity, then the volume of active material increases, but lithium ion transport efficiency decreases

Engineering Contradiction:
Improvevolume of active materialVSAvoidlithium ion transport efficiency
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The auxiliary channels create a porous network throughout the thick electrode, providing multiple parallel pathways for lithium ion transport. This porous structure reduces the effective diffusion distance by creating shortcuts through the electrode matrix, maintaining high ion transport speed even in thick electrodes with large volumes of active material.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The auxiliary channels introduce a new dimensional pathway for lithium ion transport, moving from purely planar diffusion to three-dimensional transport through the channel network. This additional dimension allows ions to bypass long diffusion paths through the active material matrix, maintaining high transport efficiency while accommodating increased active material volume.

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

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 approach enhances battery performance by maintaining even lithium ion distribution and reducing stress on the separator, enabling higher C rates and thicker electrodes while maintaining efficient lithium ion transport, thus improving the battery's overall efficiency and lifespan.

Implementation Method 1

The auxiliary channels form a matrix and are not built up in strands but in points in the electrode layer... enabling higher C rates and thicker electrodes while maintaining efficient lithium ion transport

Methodology Applied
Scientific EffectDiffusion: Diffusion

Data Source

PatentEP3584858B1Method for producing a battery
Publication Date: 2021.11.10 VOLKSWAGEN AG
  • EP3584858B1 patent drawingFigure 1~2
  • EP3584858B1 patent drawingFigure 3~4

AI summary

The invention relates to a battery (1), namely a lithium-ion battery, with an electrode layer (2) and a current collector (3), wherein the electrode layer (2) has several auxiliary channels (7, 7a to 7e) in an active material (5). The battery (1) is improved in that the auxiliary channels (7, 7a to 7e) are formed at both a cathode and an anode.