Layered Separator Pore Diameter Gradient for Lead Acid Battery Output

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Solution Overview

Problem

Current methods for reducing the thickness of separators in lead acid storage batteries to enhance output face challenges in preventing penetration short-circuits during battery jar formation, as the reduction in thickness leads to clogged pores and difficulty in retaining electrolytic solutions.

Innovation Solution

A separator with a layered structure, where one layer in contact with the positive electrode has a larger average pore diameter than the layer in contact with the negative electrode, and the thickness of the first layer is equal to or less than half of the overall separator thickness, allowing for differential diffusion of electrolytic solutions and reducing the likelihood of lead sulfate precipitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the thickness of the separator is reduced to increase the number of electrodes, then the battery output is improved, but penetration short-circuit occurs during battery jar formation

Engineering Contradiction:

Improvebattery outputVSAvoidpenetration short-circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The separator is divided into multiple layers with different pore diameters. The first layer (in contact with positive electrode) has a larger average pore diameter to prevent lead sulfate precipitation, while the second layer (in contact with negative electrode) has a smaller average pore diameter to retain electrolytic solution. This segmentation allows each layer to perform its specific function optimally.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the separator are given different properties: the first layer has larger pores for preventing short-circuit, while the second layer has smaller pores for electrolytic solution retention. The thickness of the first layer is controlled to be equal to or less than half of the overall separator thickness to maintain the desired pore structure and function.

Inventive Principle:

Principle #3Local quality

2Reliability

If inorganic filler is added to the separator to prevent penetration short-circuit, then reliability is improved, but pores are clogged and electrolytic solution retention becomes difficult

Engineering Contradiction:

Improvepenetration short-circuit preventionVSAvoidelectrolytic solution retention

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of adding inorganic filler, the invention changes the structural parameters of the separator by creating a multi-layer structure with different pore diameters. The first layer has a larger average pore diameter that prevents lead sulfate precipitation without clogging, while the second layer has a smaller average pore diameter for electrolytic solution retention.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the thickness of the separator is reduced, then the number of electrodes increases and battery output improves, but the separator cannot prevent penetration short-circuit

Engineering Contradiction:

Improvebattery outputVSAvoidpenetration short-circuit prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The invention addresses the thickness problem by transitioning from a single-layer structure to a multi-layer structure. By adding the dimension of layer differentiation with specific pore diameter variations, the separator can maintain reduced thickness while preventing penetration short-circuit through the larger-pored first layer.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 effectively prevents penetration short-circuits during battery jar formation while allowing for a thinner separator, thereby increasing the battery's capacity and output without using inorganic fillers that clog pores.

Implementation Method 1

an average pore diameter of the first layer is larger than an average pore diameter of the second layer

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the separator includes a first layer that is in contact with the positive electrode, and a second layer that is in contact with the negative electrode

Methodology Applied

Scientific EffectPorosity: Porosity

Data Source

PatentUS11349175B2Separator for lead acid storage batteries, and lead acid storage battery

Publication Date: 2022.05.31 ENERGYWITH CO LTD

AI summary

A separator 100 is disposed between a positive electrode and a negative electrode in a lead acid storage battery including the positive electrode and the negative electrode, in which the separator 100 contains a glass fiber and an organic binder, the separator 100 includes a first layer 110a that is in contact with the positive electrode, and a second layer 110b that is in contact with the negative electrode, an average pore diameter of the first layer 110a is larger than an average pore diameter of the second layer 110b, and a thickness of the first layer 110a is equal to or less than the half of the overall thickness of the separator 100.