Lead-Acid Battery Separator Coating for Crack-Free Low Resistance
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Solution Overview
Problem
Existing separators for lead-acid storage batteries suffer from surface cracks and shedding of inorganic material when bent, and have high ionic resistance, which accelerates degradation and shortens lifespan due to stratification.
Innovation Solution
A separator with a uniform inorganic material layer on a substrate, where the DOA oil absorption of inorganic particles is Y (ml/100 g) and median diameter is X (µm) satisfies Y ≤ 2.5X + 200, using inorganic particles like silica, alumina, or kaolin, with controlled resin binder and polysaccharide content to inhibit cracks and lower ionic resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If an inorganic material layer is provided on the separator substrate to inhibit stratification, then the battery lifespan is extended, but surface cracks occur and inorganic material sheds when bent
Solution Approach 1:
The patent applies parameter changes by optimizing the DOA oil absorption value and median diameter of inorganic particles, establishing a quantitative relationship (Y ≤ 2.5X + 200) between these parameters. This resolves the contradiction by finding the optimal parameter range that prevents surface cracks and shedding while maintaining stratification inhibition functionality, thereby extending battery lifespan without compromising reliability.
Solution Approach 2:
The patent uses composite materials by combining inorganic particles (such as silica, alumina, or barium sulfate) with a polymer matrix to form a coating layer on the separator substrate. This composite structure provides both the stratification inhibition function of inorganic materials and the flexibility crack resistance of the polymer matrix, resolving the contradiction between lifespan extension and surface crack resistance.
2Stability of the object's composition
If an inorganic material layer is provided on the separator substrate, then stratification is inhibited, but ionic resistance increases
Solution Approach 1:
The patent employs porous materials by using inorganic particles with controlled size and distribution to create a porous coating structure. This porous structure allows ionic conduction while maintaining the stratification inhibition function, thus resolving the contradiction between sulfuric acid concentration uniformity and ionic resistance.
Solution Approach 2:
The patent applies parameter changes by optimizing the particle size distribution and porosity of the inorganic material layer. By controlling the median diameter and DOA oil absorption within specific ranges, the patent achieves a balance between maintaining uniform sulfuric acid concentration and minimizing ionic resistance, resolving the technical contradiction.
3Duration of action of stationary object
If the inorganic material layer is made thicker to improve stratification inhibition, then the battery lifespan is extended, but the layer becomes more prone to cracking and shedding
Solution Approach 1:
The patent applies parameter changes by establishing optimal ranges for inorganic particle size (median diameter X) and DOA oil absorption (Y) that prevent surface cracks and shedding. This resolves the contradiction by finding parameter values that provide sufficient stratification inhibition without making the layer too thick or rigid, thus extending battery lifespan while maintaining layer flexibility.
Solution Approach 2:
The patent applies local quality by creating a coating layer with non-uniform inorganic particle distribution and size. The coating has different properties at different locations and depths, with smaller particles near the substrate interface providing flexibility and larger particles toward the outer surface providing stratification inhibition, thus resolving the contradiction between lifespan extension and flexibility maintenance.
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 separator inhibits surface cracks and shedding, maintains uniform sulfuric acid concentration, and reduces ionic resistance, thereby extending the battery's lifespan and performance.
Implementation Method 1
when a DOA oil absorption of the inorganic particles is Y (ml/100 g) and a median diameter of the inorganic particles is X (μm), Y ≤ 2.5X + 200 is satisfied
Implementation Method 2
When a lead-acid storage battery is charged, lead sulfate in the positive and negative electrodes is decomposed, releasing a high concentration of sulfate ions into the electrolyte solution
Data Source
AI summary
Provided is a separator for batteries in which an electrolytic solution contains water. The separator: is characterized by comprising a substrate and a layer laminated on at least one surface of the substrate; and is characterized in that the layer contains inorganic particles, and when Y (ml/100 g) represents the DOA oil absorption of the inorganic particles and X (µm) represents the median diameter of the inorganic particles, Y≤2.5X+200 is satisfied.