Constrained Electrode Assembly for Battery Growth and Alignment

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Solution Overview

Problem

Existing secondary batteries face challenges with electrode expansion and contraction during cycling, leading to reliability and cycle life issues, as well as misalignment and mechanical instability, which can cause shorting and failure.

Innovation Solution

The use of a secondary battery design that incorporates a set of electrode constraints, including a primary and secondary growth constraint system, to control the expansion and contraction of electrodes and maintain alignment, thereby enhancing mechanical stability and reducing the risk of shorting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electrodes are allowed to expand and contract freely during battery cycling, then the battery can accommodate volume changes of active materials, but electrical shorts and battery failures occur due to electrode expansion

Engineering Contradiction:

Improveaccommodation of volume changesVSAvoidelectrical short prevention

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The battery is divided into separate functional zones: a first battery portion containing the anode and its expansion space, and a second battery portion containing the cathode. This segmentation allows independent management of expansion for each electrode type, accommodating volume changes while preventing interference between electrodes that would cause shorts.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces a longitudinal dimension for battery expansion by allowing the anode to expand into a first expansion space along the longitudinal axis, rather than only in planar dimensions. This dimensional approach accommodates volume changes while maintaining separation from the cathode, preventing electrical shorts.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If electrode alignment is not controlled, then manufacturing is simpler, but mismatch in electrode alignment caused by physical or mechanical stresses leads to shorting and failure

Engineering Contradiction:

Improvealignment controlVSAvoidshorting prevention

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The battery structure is pre-configured with designated expansion spaces and constrained geometries before cycling begins. The anode is positioned within a defined first battery portion with predetermined expansion boundaries, ensuring that even under mechanical stress, the anode cannot shift into positions that would cause misalignment or shorting with the cathode.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the battery footprint is increased to provide expansion space, then electrode expansion is accommodated, but the battery size increases excessively

Engineering Contradiction:

Improveexpansion accommodationVSAvoidbattery footprint

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs a flexible separator that can deform to accommodate anode expansion while maintaining electrical isolation. This flexible boundary allows the anode to expand into the designated space without requiring rigid, space-consuming containment structures, thus accommodating expansion while minimizing footprint increase.

Inventive Principle:

Principle #30Flexible shells and thin films

4Reliability

If mechanical constraints are added to control electrode expansion, then reliability improves, but device complexity increases

Engineering Contradiction:

Improveelectrode stabilityVSAvoidconstraint system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The functional elements are merged into integrated components: the separator serves both as an electrical insulator and as a flexible constraint that guides anode expansion; the battery portion divisions serve both as structural organizers and as expansion boundaries. This merging reduces the need for separate, complex constraint mechanisms while maintaining electrode stability and reliability.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS12206106B2Electrode assembly and secondary battery

Publication Date: 2025.01.21 ENOVIX CORP

AI summary

Embodiments of secondary batteries having electrode assemblies are provided. A secondary battery can comprise an electrode assembly having a stacked series of layers, the stacked series of layers having an offset between electrode and counter-electrode layers in a unit cell member of the stacked series. A set of constraints can be provided with a primary constraint system with first and second primary growth constraints separated from each other in a longitudinal direction, and connected by at least one primary connecting member, and a secondary constraint system comprises first and second secondary growth constraints separated in a second direction and connected by members of the stacked series of layers. The primary constraint system may at least partially restrain growth of the electrode assembly in the longitudinal direction, and the secondary constraint system may at least partially restrain growth in the second direction that is orthogonal to the longitudinal direction.