Lead-Acid Battery Separator Stiffening Coating

Solution Overview

Problem

Lead-acid battery separators become too flexible when made thinner, leading to failures due to internal flexing and vibrations, as the existing ribs provide inadequate stiffness in both machine direction (MD) and cross-machine direction (CMD), necessitating a solution to enhance stiffness without hindering ionic flow.

Innovation Solution

A porous membrane substrate for lead-acid battery separators is coated with a stiffening material, such as sodium silicate or polyvinyl alcohol, applied to the ribs or surfaces in specific patterns to increase stiffness in the MD and CMD directions, with the material precipitating out to form a porous coating that maintains ionic flow and does not significantly increase electrical resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the separator is made thinner to lower production costs, then manufacturing cost is reduced, but the separator becomes more flexible and prone to failure due to internal flexing and vibrations

Engineering Contradiction:

Improveproduction costVSAvoidseparator stability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by adding stiffening coatings specifically to the ribs of the separator rather than uniformly across the entire separator. This localized treatment provides the necessary stiffness to prevent flexing and vibrations while maintaining the overall thin design and cost-effectiveness of the separator.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining the base separator material (polyethylene or similar) with stiffening coatings (such as sodium silicate, calcium silicate, or other inorganic/organic coatings) applied to the ribs. This composite structure provides enhanced mechanical stability while maintaining the functional properties of the original separator material.

Inventive Principle:

Principle #40Composite materials

2Strength

If ribs are added to stiffen the separator, then separator stiffness is improved, but the complexity of the separator structure increases

Engineering Contradiction:

Improveseparator stiffnessVSAvoidseparator structure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent applies local quality by adding stiffening coatings specifically to the ribs of the separator rather than uniformly across the entire separator. This localized treatment provides the necessary stiffness to prevent flexing and vibrations while maintaining the overall thin design and cost-effectiveness of the separator.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the physical and chemical parameters of the ribs by applying coatings that change their mechanical properties. The coatings alter the stiffness, strength, and surface characteristics of the ribs without fundamentally changing the separator's structural design or manufacturing process.

Inventive Principle:

Principle #35Parameter changes

3Strength

If a stiffening coating is applied to the separator, then separator stiffness is enhanced, but the coating may block pores and hinder ionic flow

Engineering Contradiction:

Improveseparator stiffnessVSAvoidionic flow resistance

Core Design Contradiction:

StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent employs porous materials by using stiffening coatings that maintain a porous structure after application. These porous coatings provide mechanical stiffness while allowing ionic flow through the pores, thus preventing the harmful effect of blocking ionic transport pathways in the separator.

Inventive Principle:

Principle #31Porous materials

Solution Approach 2:

The patent applies local quality by adding stiffening coatings specifically to the ribs of the separator rather than uniformly across the entire separator. This localized treatment provides the necessary stiffness to prevent flexing and vibrations while maintaining the overall thin design and cost-effectiveness of the separator.

Inventive Principle:

Principle #3Local quality

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 stiffening material enhances the separator's stiffness by 52% to 97% in various directions, reducing electrical resistance and improving resilience, thereby preventing battery failures from flexing and vibrations.

Implementation Method 1

the material precipitating out to form a porous coating that maintains ionic flow

Methodology Applied

Scientific EffectPrecipitation: Precipitation

Data Source

PatentUS9190648B2Lead-acid battery separator having enhanced stiffness

Publication Date: 2015.11.17 DARAMIC LLC

AI summary

A lead-acid battery separator comprised of a porous membrane substrate having a front surface and a back surface and said front surface having a plurality of ribs. To enhance the substrate's stiffness, one or more coatings of a stiffening material may be adhered to the ribs on the substrate's surface.