Secondary Battery Electrode Assembly for Expansion-Constrained Alignment

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Solution Overview

Problem

Rocking chair secondary batteries face challenges with electrode expansion and contraction during cycling, leading to electrical shorts and failure, as well as issues with electrode alignment and mechanical stability, which affect reliability and cycle life.

Innovation Solution

The implementation of a secondary battery design with a specific electrode assembly structure and constraint system that includes a primary and secondary growth constraint system to control electrode expansion and alignment, comprising a population of electrode and counter-electrode structures arranged in an alternating sequence with a set of constraints that restrain growth and maintain mechanical stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If electrodes are designed to accommodate carrier ion insertion and extraction, then battery capacity and cycling capability are improved, but electrode expansion and contraction occur leading to electrical shorts and battery failure

Engineering Contradiction:

Improvecycle lifeVSAvoidbattery reliability

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent applies flexible constraint structures that can accommodate electrode expansion and contraction during cycling while maintaining mechanical stability. The constraint system includes flexible elements that allow controlled movement without causing electrical shorts, resolving the contradiction between cycle life and reliability.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent introduces constraint structures as intermediary elements between the electrodes and battery housing. These constraints act as mediators that manage the mechanical stresses from electrode expansion/contraction, preventing direct contact between expanded electrodes and avoiding shorts while maintaining cycling capability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If physical or mechanical stresses are applied during manufacture, use or transport, then battery assembly is facilitated, but electrode alignment mismatch occurs leading to shorting and battery failure

Engineering Contradiction:

Improvemanufacturing easeVSAvoidbattery reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent implements preliminary constraint structures during manufacturing that pre-establish proper electrode alignment and prevent misalignment under subsequent mechanical stresses. The constraints are designed to counteract potential alignment issues before they occur during use or transport, maintaining both manufacturing ease and reliability.

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If constraint structures are added to control electrode expansion and alignment, then reliability and cycle life are improved, but device complexity increases

Engineering Contradiction:

Improvebattery reliabilityVSAvoidelectrode assembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs constraint structures that serve multiple functions simultaneously: controlling electrode expansion, maintaining alignment, and providing mechanical support. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving improved reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

4Stability of the object's composition

If constraint system is implemented to restrain electrode growth, then electrode alignment and mechanical stability are maintained, but battery footprint increases

Engineering Contradiction:

Improveelectrode alignment stabilityVSAvoidbattery footprint

Core Design Contradiction:

Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The patent employs nested constraint structures where internal constraints are positioned within the existing battery geometry rather than adding external layers. The constraint system is integrated into the available space, maintaining electrode alignment stability without significantly increasing the overall battery footprint.

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS12087947B2Electrode assembly, secondary battery, and method of manufacture

Publication Date: 2024.09.10 ENOVIX CORP

AI summary

Secondary batteries and methods of manufacture thereof are provided. A secondary battery can comprise an offset between electrode and counter-electrode layers in a unit cell. Secondary batteries can be prepared by removing a population of negative electrode subunits from a negative electrode sheet, the negative electrode sheet comprising a negative electrode sheet edge margin and at least one negative electrode sheet weakened region that is internal to the negative electrode sheet edge margin, removing a population of separator layer subunits from a separator sheet, and removing a population of positive electrode subunits from a positive electrode sheet, the positive electrode sheet comprising a positive electrode edge margin and at least one positive electrode sheet weakened region that is internal to the positive electrode sheet edge margin, and stacking members of the negative electrode subunit population, the separator layer subunit population and the positive electrode subunit population.