Li-metal edge-wise cell partitioning for dendrite isolation

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Solution Overview

Problem

Lithium metal batteries face issues with dendrite formation, which can lead to catastrophic failures due to short-circuiting of the anode and cathode, and stack pressure challenges in maintaining granule contact in flat cells, limiting their practical application and energy density.

Innovation Solution

The battery design incorporates a partitioned cell structure that allows only a fraction of the power to be fed to a dendrite short, rendering it benign and includes a fuse to isolate shorted cell elements, using thinner current collectors and edge-wise construction to impede current flow and prevent thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If lithium metal anode is used to increase energy density, then energy density is improved, but dendrite formation occurs leading to short-circuiting and catastrophic failure

Engineering Contradiction:

Improveenergy densityVSAvoiddendrite formation and short-circuiting

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The battery cell is divided into multiple smaller compartments or zones within the single cell structure. Each compartment contains its own lithium metal anode section, separator, and current collector. This segmentation ensures that dendrite formation in one compartment cannot propagate to other compartments, isolating potential short-circuits to localized areas and preventing catastrophic cell failure while maintaining high overall energy density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A specially designed separator acts as an intermediary between the lithium metal anode and cathode. This separator includes dendrite-blocking features such as porous structures, coating layers, or geometric designs that physically prevent dendrite penetration while allowing ionic transport. The separator mediates the interaction between electrodes, enabling safe lithium metal operation by blocking the harmful dendrite pathway while maintaining electrical isolation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional sheet construction is used, then manufacturing is simplified, but stack pressure causes loss of granule contact and reduced performance

Engineering Contradiction:

Improveconstruction simplicityVSAvoidgranule contact maintenance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The battery construction transitions from a conventional flat sheet arrangement to a three-dimensional stacked or wound configuration. The layers (anode, separator, cathode, current collectors) are stacked or wound in a manner that creates edge-wise contact points distributed throughout the cell. This dimensional change allows granules to maintain contact through vertical or radial pressure distribution rather than relying solely on planar contact, improving reliability while maintaining manufacturing feasibility.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Strength

If thick current collectors are used, then structural strength is improved, but energy density is reduced due to increased material usage

Engineering Contradiction:

Improvecurrent collector structural strengthVSAvoidenergy density

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

The current collectors are designed with varying thicknesses at different locations and orientations. Edge-wise current collectors (those at the boundaries of stacked layers) are made thicker to provide structural support and maintain electrical connectivity under stack pressure. Internal or core current collectors can be thinner since they are supported by adjacent layers. This local quality differentiation maintains necessary strength while minimizing overall material usage and maximizing energy density.

Inventive Principle:

Principle #3Local quality

4Reliability

If dendrite short-circuiting is allowed to occur, then complete cell failure results, but preventing it entirely is difficult

Engineering Contradiction:

Improveprevention of complete failureVSAvoidcell structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The battery cell incorporates protective features in advance that cushion against the harmful effects of dendrite formation. These include redundant current paths through multiple edge-wise connections, fuse elements that isolate damaged sections, and segmented architectures that prevent dendrite propagation. These cushioning features are built into the cell structure before operation, allowing the cell to withstand dendrite-induced short-circuits without catastrophic failure, effectively preparing the system for potential failures beforehand.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10249908B2Systems, methods and devices for creating a Li-metal edge-wise cell

Publication Date: 2019.04.02 INTEL CORP

AI summary

A new battery cell structure uses a battery cell structure comprising a plurality of strips so that only a fraction of the power in the cell can be fed to a dendrite which has shorted an anode and cathode. The dendrite still occurs, but can be rendered benign. In addition, a fuse can be added to the cell structure so that shorted cells can be removed from the circuit.