Electrode Assembly Separator Layout for Lithium Dendrite Blocking

Solution Overview

Problem

Battery cells face safety risks due to lithium precipitation leading to short circuits, which existing technologies have not adequately addressed, particularly in regions prone to bending where lithium dendrites can form and conduct between the positive and negative electrode plates.

Innovation Solution

An electrode assembly with a multi-layer separation structure is introduced, where a multi-layer structure area is strategically placed between the positive and negative electrode plates, especially in bending regions, to block lithium dendrites and prevent short circuits, while a single-layer structure is used in flat regions to enhance energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single-layer separation structure is used throughout the electrode assembly, then the energy density is maximized and device complexity is minimized, but the reliability deteriorates due to insufficient blocking of lithium dendrites in bending regions

Engineering Contradiction:

Improveshort circuit preventionVSAvoidseparation structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies different separation structures to different regions of the electrode assembly based on local requirements. Multi-layer separation structures are specifically placed in bending regions where lithium dendrite formation is more likely, while single-layer structures are used in flat regions. This local differentiation resolves the contradiction by enhancing reliability only where needed rather than uniformly throughout the entire assembly.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The separation structure is segmented into multiple layers in specific regions rather than using a uniform single-layer design throughout. The electrode assembly is divided into bending regions and flat regions, with the separation structure configured accordingly - multi-layer in bending regions and single-layer in flat regions. This segmentation allows the system to achieve both high reliability in critical areas and low overall complexity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If multi-layer separation structure is used in bending regions, then the reliability improves by blocking lithium dendrites, but the device complexity and energy density deteriorate

Engineering Contradiction:

Improveshort circuit preventionVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements multi-layer separation structures only in bending regions where lithium dendrite formation occurs, rather than uniformly throughout the entire electrode assembly. This localized approach ensures that reliability is improved in the specific areas where it is needed, while minimizing the impact on overall energy density by not adding unnecessary layers in flat regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies multi-layer separation structures partially - only in bending regions where lithium dendrite formation is problematic - rather than applying them excessively throughout the entire assembly. This partial action achieves the necessary reliability improvement while avoiding the penalty of reduced energy density that would result from universal multi-layer implementation.

Inventive Principle:

Principle #16Partial or excessive action

3Reliability

If multi-layer separation structure is used in bending regions, then the reliability improves by blocking lithium dendrites, but the device complexity and energy density deteriorate

Engineering Contradiction:

Improveshort circuit preventionVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent implements multi-layer separation structures only in bending regions where lithium dendrite formation occurs, rather than uniformly throughout the entire electrode assembly. This localized approach ensures that reliability is improved in the specific areas where it is needed, while minimizing the impact on overall energy density by not adding unnecessary layers in flat regions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent applies multi-layer separation structures partially - only in bending regions where lithium dendrite formation is problematic - rather than applying them excessively throughout the entire assembly. This partial action achieves the necessary reliability improvement while avoiding the penalty of reduced energy density that would result from universal multi-layer implementation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS20240213620A1Electrode assembly, battery cell, battery, and electric apparatus

Publication Date: 2024.06.27 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED

AI summary

Provided are an electrode assembly, a battery cell, a battery, and an electric apparatus. The electrode assembly comprises a positive electrode plate, a negative electrode plate, and a separation assembly, and the separation assembly is configured to separate the positive electrode plate from the negative electrode plate. At least part of the separation assembly is provided as a multi-layer structure area, and at least part of the multi-layer structure area is located between the positive electrode plate and negative electrode plate adjacent to each other.