Lead-Acid Negative Electrode Expander for Cycling and Water Loss
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Solution Overview
Problem
Existing lead-acid batteries, particularly AGM batteries, face challenges in providing consistent reliable performance, supporting additional loads, and maintaining optimal endurance due to limitations in cycling performance and water loss.
Innovation Solution
The addition of a blended expander mixture comprising fine particle barium sulfate, two organic compounds (oxylignins) with specific molecular weights and properties, and a carbonaceous material to the negative active material of lead-acid battery electrodes improves performance by enhancing cycling capabilities and reducing water loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional negative active material is used in lead-acid batteries, then the battery structure is simple and manufacturing is easy, but the cycling performance and water loss resistance are insufficient
Solution Approach 1:
The patent applies composite materials by combining fine particle barium sulfate, oxylignin, and carbonaceous material to create a blended expander mixture. This composite approach enhances cycling performance and water loss resistance through synergistic effects: barium sulfate provides structural stability and reduces water loss, oxylignin improves paste homogeneity and reduces lumping, and carbonaceous material enhances conductivity and reduces tar formation. The composite mixture resolves the contradiction by improving reliability while accepting controlled complexity in material composition.
Solution Approach 2:
The patent applies parameter changes by carefully controlling the particle size distribution of barium sulfate (fine particles with specific surface area), the molecular weight ranges of oxylignin, and the surface area of carbonaceous material. These parameter optimizations ensure that the expander blend achieves maximum effectiveness in improving cycling performance and reducing water loss while maintaining manufacturability. The specific parameter ranges balance performance improvement with processing ease.
2Reliability
If organic expanders are added to negative active material, then cycling performance improves, but the materials tend to pick up moisture and form lumps
Solution Approach 1:
The patent applies the intermediary principle by using hydrophobic carbonaceous material as a mediator that coats the hygroscopic oxylignin particles. This carbonaceous coating acts as a barrier that prevents moisture from reaching and reacting with the oxylignin, thereby preventing lump and tar formation during storage and processing. The intermediary carbonaceous material allows the beneficial cycling performance improvements from oxylignin to be achieved while eliminating the manufacturing difficulties associated with moisture sensitivity.
Solution Approach 2:
The patent applies parameter changes by optimizing the hydrophobicity parameters of the carbonaceous material and controlling its surface area and particle size distribution. By adjusting these parameters, the carbonaceous material provides sufficient moisture protection without creating excessive dust or processing difficulties. The parameter optimization ensures that the protective function is achieved while maintaining ease of manufacture.
3Ease of operation
If carbonaceous material is supplied pelletized to reduce volume and dust, then handling is improved, but the pellets may not disperse well in the paste mix
Solution Approach 1:
The patent applies segmentation by pre-mixing the pelletized carbonaceous material with other expander components (barium sulfate and oxylignin) before adding to the paste. This pre-segmentation breaks up the pellets into smaller aggregates and distributes them more uniformly throughout the expander blend. The segmented pre-mixture ensures that when the paste is prepared, the carbonaceous material disperses homogeneously without large aggregates, maintaining manufacturing precision while retaining the handling advantages of pelletized material.
Solution Approach 2:
The patent applies preliminary action by pre-mixing the pelletized carbonaceous material with other expander components before paste preparation. This preliminary mixing action breaks down the pellets and distributes them uniformly in advance, ensuring they will disperse properly when added to the paste. The preliminary action resolves the contradiction by maintaining the handling benefits of pelletized material while ensuring homogeneous dispersion in the final product.
4Reliability
If multiple expander components are mixed individually, then each component can be optimized, but the mixture tends to form lumps and segregate
Solution Approach 1:
The patent applies merging by combining all expander components (barium sulfate, oxylignin, and carbonaceous material) into a single integrated blend before adding to the paste. This unified expander blend ensures homogeneous distribution of all components throughout the negative active material, preventing segregation during processing and storage. The merged approach maintains component optimization benefits while achieving composition stability through uniform distribution.
Solution Approach 2:
The patent applies parameter changes by optimizing the particle size distribution and surface area characteristics of all expander components to similar ranges. This parameter harmonization ensures that all components have comparable flow and mixing characteristics, preventing segregation based on density or size differences. The parameter optimization maintains the individual component benefits while achieving stable homogeneous mixture.
Data Source
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AI summary
A blended expander formula for use in the preparation of lead acid battery electrodes is disclosed. The mixture comprises fine particle barium sulfate, a first oxylignin, a second oxylignin, and a carbonaceous material. A method, a negative paste, and a negative electrode including the blended expander mixture are also disclosed. A lead-acid absorbent glass mat battery is further disclosed.