Battery Separator Structure for Lithium Protrusion Inhibition

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Solution Overview

Problem

Conventional lithium-ion batteries face limitations in operating at high current densities due to the formation of lithium protrusions, which can grow through the separator and cause short circuits, restricting the materials that can be used in separators to inhibit their growth.

Innovation Solution

Incorporating an electrically conductive protrusion inhibiting layer with a primary lithium ion conducting material and an electronically insulating layer to mechanically or chemically inhibit the growth of lithium protrusions, allowing for higher current densities without risking short circuits, using materials like carbon nanotubes, silver nanowires, and alloying materials that alloy with lithium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional insulating separators are used to prevent short circuits, then electronic insulation is maintained, but the ability to inhibit lithium protrusion growth is limited

Engineering Contradiction:

Improveshort circuit preventionVSAvoidseparator material selection

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The separator is divided into multiple functional layers: an electrically insulating layer (maintaining short circuit prevention) and a conductive protrusion-inhibiting layer (providing mechanical inhibition of lithium dendrites). This segmentation allows each layer to perform its specialized function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The insulating layer acts as an intermediary between the conductive protrusion-inhibiting layer and the electrodes, allowing the conductive layer to perform its inhibition function while the insulating layer ensures electronic isolation. This mediator enables the use of conductive materials that would otherwise cause short circuits.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high current density is applied to increase power output, then battery productivity improves, but lithium protrusions form and grow through the separator

Engineering Contradiction:

Improvecurrent densityVSAvoidseparator integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The conductive protrusion-inhibiting layer is positioned in the separator to preemptively counteract the formation and growth of lithium protrusions before they can penetrate through the separator and cause short circuits, enabling safe operation at high current densities.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The separator uses a composite structure combining electrically insulating materials with conductive protrusion-inhibiting materials, creating a multi-functional separator that simultaneously maintains electronic insulation and mechanically inhibits lithium dendrite growth under high current density conditions.

Inventive Principle:

Principle #40Composite materials

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

Enables lithium-ion batteries to operate at higher current densities while preventing lithium protrusions from forming, thereby increasing the battery's operational capacity and safety by using a wider range of materials for the separator layer.

Implementation Method 1

the protrusion inhibiting layer is configured to mechanically inhibit growth of lithium protrusions on the other of the positive and negative electrode

Methodology Applied

Scientific EffectMechanical inhibition:

Implementation Method 2

The separator includes an electrically conductive protrusion inhibiting layer and a first insulating layer interposed between and electrically insulating the protrusion inhibiting layer from one of the positive and negative electrode

Methodology Applied

Scientific EffectIon conduction: Conduction (electrical)

Implementation Method 3

the protrusion inhibiting layer comprises an alloying material that alloys with lithium in the battery so as to inhibit growth of lithium protrusions

Methodology Applied

Scientific EffectAlloying:

Data Source

PatentUS12002963B2Electrode configuration with a protrusion inhibiting separator

Publication Date: 2024.06.04 ROBERT BOSCH GMBH

AI summary

An electrode configuration for a battery cell includes a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode. The separator includes an electrically conductive protrusion inhibiting layer and a first insulating layer interposed between and electrically insulating the protrusion inhibiting layer from one of the positive and negative electrode.