Bag Separator Lead-Acid Battery for Grid Corrosion Control

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Solution Overview

Problem

Lead-acid batteries face reduced life performance due to positive current collector elongation and separator damage during charge-discharge cycles, particularly in high temperature conditions, when the positive electrode plate is housed in a bag-shaped separator.

Innovation Solution

Incorporating a negative electrode material with a polymer compound having a repeating structure of oxy C2-4 alkylene units and a positive current collector containing Sn, housed in a bag-shaped separator with a rib protruding toward the positive electrode plate, to enhance electrolyte convection and reduce corrosion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional lead-acid battery structures are used, then manufacturing simplicity is maintained, but charge acceptance is insufficient and grid corrosion occurs

Engineering Contradiction:
Improvecharge acceptanceVSAvoidbattery structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The battery is divided into multiple compartments with individual separators between them. Each compartment can be independently managed, allowing optimized charging currents for each cell while preventing cross-contamination of electrolyte and improving overall charge acceptance without requiring complete structural redesign

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the battery are assigned different functions: the positive plate group uses a specific grid alloy composition for durability, while the negative plate uses optimized lead-calcium-tin alloy. The separator material is specifically designed with particular porosity and chemical resistance properties in different zones to address local corrosion issues

Inventive Principle:
Principle #3Local quality

2Quantity of substance

If battery plates are closely arranged to increase energy density, then space utilization improves, but heat dissipation becomes insufficient

Engineering Contradiction:
Improveenergy densityVSAvoidheat dissipation
Core Design Contradiction:
Quantity of substanceVSTemperature

Solution Approach 1:

The battery employs a nested structure where the electrolyte container is positioned within the framework formed by the plate groups and separators. This compact nesting arrangement maximizes the amount of active material (plates and electrolyte) within the available volume, increasing energy density while the outer container walls provide thermal management pathways

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

Heat dissipation is addressed by introducing vertical spacing between plate groups through the separator structure, creating three-dimensional heat conduction pathways. The electrolyte flows through multiple levels and compartments, enabling heat to dissipate in multiple spatial dimensions rather than relying solely on horizontal conduction

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If electrolyte volume is increased to improve ionic conductivity, then charge-discharge performance improves, but battery volume increases

Engineering Contradiction:
Improvecharge-discharge performanceVSAvoidbattery volume
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The separator is designed as a porous material with optimized pore size and distribution. This allows the electrolyte to be concentrated in the porous network of the separator and at the plate surfaces where it is most needed for ionic conduction, rather than requiring large volumes of bulk electrolyte. The porous structure provides high surface area for ionic exchange in a compact volume

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The battery uses composite plate structures combining lead, calcium, and tin in specific ratios and configurations. This composite approach optimizes the electrochemical activity at the plate-electrolyte interface, improving charge-discharge performance without requiring proportional increases in electrolyte volume, as the enhanced material composition reduces the electrolyte volume needed for effective ionic conduction

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

This configuration improves life performance in both deep discharge and high temperature cycle tests by reducing stratification and corrosion, maintaining charge acceptability and preventing separator damage.

Implementation Method 1

positive plate and negative plate, both having a grid structure, and a separator for preventing direct contact between the positive plate and the negative plate in a case containing an electrolyte

Methodology Applied
Scientific EffectElectrochemical reaction: Redox Reactions

Data Source

PatentEP4254549B1Lead-acid battery
Publication Date: 2026.05.06 GS YUASA INT LTD
  • EP4254549B1 patent drawingFigure 1
  • EP4254549B1 patent drawing

AI summary

A lead-acid battery includes at least one cell including an element and an electrolyte solution. The element includes a positive electrode plate, a negative electrode plate, and a bag-shaped separator interposed between the positive electrode plate and the negative electrode plate. The negative electrode plate includes a negative current collector and a negative electrode material. The positive electrode plate includes a positive current collector and a positive electrode material. The negative electrode material contains a polymer compound having a peak in a range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of a 1H-NMR spectrum measured using deuterated chloroform as a solvent. The positive current collector contains Sn. The bag-shaped separator includes a rib protruding toward the positive electrode plate, and houses the positive electrode plate.