Embossed Battery Separator Rib Structure Puncture Resistance

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Solution Overview

Problem

Existing lead acid battery separators are prone to puncture and shorting due to electrode plate edges and sharp tips, leading to inefficiencies and reduced performance, and lack robustness and oxidation resistance.

Innovation Solution

An embossed thermoplastic sheet material with a central region of longitudinally extending ribs is used, formed by calendering and further embossed with sinusoidal ribs to increase thickness and resiliency, creating a densified skeletal frame and reducing pin holes, which enhances oxidation resistance and compression properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional porous separators are used to permit ionic current flow, then ionic conductivity is maintained, but the separators are prone to puncture by electrode plate edges and sharp tips

Engineering Contradiction:
Improvepuncture resistanceVSAvoidmechanical strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The separator is segmented into multiple functional layers: a porous base layer for ionic conductivity and an embossed reinforcement layer with ribs for mechanical strength. This segmentation allows each layer to perform its specialized function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The separator combines different material structures - a porous polyolefin base material with an embossed thermoplastic reinforcement structure - to achieve both ionic permeability and puncture resistance. The composite structure integrates the beneficial properties of both components.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the separator thickness is increased to improve puncture resistance, then mechanical strength improves, but the ionic current flow resistance increases

Engineering Contradiction:
Improvepuncture resistanceVSAvoidionic current flow efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The separator features local quality variations with thicker rib regions providing puncture resistance and thinner regions between ribs maintaining ionic conductivity. This non-uniform thickness distribution optimizes both mechanical strength and ionic flow properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The separator utilizes porous materials with controlled pore structures that maintain high ionic conductivity despite increased overall thickness. The porous architecture allows efficient ion transport through the thicker separator structure.

Inventive Principle:
Principle #31Porous materials

3Stability of the object's composition

If longitudinal ribs are added to maintain electrode spacing and provide rigidity, then structural stability improves, but the separator becomes more complex to manufacture

Engineering Contradiction:
Improveelectrode spacing stabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The manufacturing process merges rib formation and embossing into a single integrated step using patterned rollers. This combines multiple functions (spacing maintenance, rigidity provision, and surface structuring) into one operation, reducing overall process complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The embossed ribs serve multiple functions simultaneously: maintaining electrode spacing, providing mechanical rigidity, and creating a densified skeletal frame for enhanced puncture resistance. This multi-functionality reduces the need for separate structural components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If the separator material is densified to reduce pin holes and improve oxidation resistance, then reliability improves, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveoxidation resistanceVSAvoidembossing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The embossing process is performed as a preliminary densification step before final separator assembly. This preliminary action creates the densified skeletal frame structure that inherently resists oxidation and pinhole formation, simplifying subsequent manufacturing steps.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The embossing process utilizes controlled parameter changes (pressure, temperature, roller pattern) to achieve consistent densification. By optimizing these parameters, the manufacturing precision requirement is managed while achieving reliable oxidation resistance.

Inventive Principle:
Principle #35Parameter changes

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

The embossed separator provides improved oxidation resistance, increased thickness, reduced cost, and self-healing effects, reducing pin holes and maintaining plate spacing over time, thus extending the cycle life and efficiency of energy storage devices.

Implementation Method 1

An embossed thermoplastic sheet material with a central region of longitudinally extending ribs is used, formed by calendering and further embossed with sinusoidal ribs to increase thickness and resiliency, creating a densified skeletal frame

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

Separators currently used in lead acid (or storage) batteries are microporous films of sheet material that prevent shorting between neighbouring electrode plates of opposite polarities and plate material from falling out, but on account of their porous structure permit ionic current flow in the electrolyte

Methodology Applied
Scientific EffectPorosity: Porosity

Implementation Method 3

embossed with sinusoidal ribs to increase thickness and resiliency

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2783405B1Embossed separators, batteries and methods
Publication Date: 2020.04.15 DARAMIC LLC
  • EP2783405B1 patent drawingFigure 1
  • EP2783405B1 patent drawingFigure 2
  • EP2783405B1 patent drawingFigure 3

AI summary

An improved, new, modified, or more robust embossed battery separator for a storage battery, a method for its production, an envelope embossed separator, batteries including the embossed separators and/or envelopes, and/or related methods for the production and/or use of the embossed separators, embossed envelopes, and/or batteries including such embossed separators and/or envelopes.