Sulfomethylated Kraft Lignin Expander for Lead Battery Charge Acceptance
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Solution Overview
Problem
Lead storage batteries face challenges in maintaining charge acceptance while improving life, capacity, and discharge characteristics, particularly when lignin is added as an organic expander.
Innovation Solution
The use of sulfomethylated kraft lignin as an organic expander, with an organic S content between 3.8% and 5.1% and a weight average molecular weight of 18,000 or less, to enhance the performance of lead storage batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lignin is added to a negative electrode of the lead storage battery, then low temperature discharge performance is improved and sulfation is suppressed, but charge acceptance is lowered
Solution Approach 1:
The patent applies parameter changes by precisely controlling the organic sulfur content within 3.8-5.1 mass% and the weight average molecular weight to 18,000 or less. This optimization of chemical parameters allows the lignin to improve low temperature discharge performance while minimizing the negative impact on charge acceptance, resolving the technical contradiction through quantitative parameter control.
Solution Approach 2:
The patent uses sulfomethylated kraft lignin as a composite organic expander material that combines the benefits of lignin (improving discharge performance and suppressing sulfation) with controlled sulfomethylation (managing charge acceptance). This composite approach allows simultaneous achievement of multiple performance requirements.
2Reliability
If lignin is added to a negative electrode of the lead storage battery, then sulfation is suppressed, but charge acceptance is lowered
Solution Approach 1:
The patent resolves this contradiction by changing the chemical parameters of the lignin, specifically controlling the organic sulfur content to 3.8-5.1 mass% and molecular weight to 18,000 or less. These parameter optimizations enable effective sulfation suppression while maintaining acceptable charge acceptance levels.
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 approach effectively improves the life, capacity, and discharge characteristics of lead storage batteries while minimizing the decrease in charge acceptance, thus providing a more efficient and durable battery performance.
Implementation Method 1
add lignin extracted from wood as an organic expander to be added to a negative electrode active material in order to prevent shrinkage of the negative electrode active material
Implementation Method 2
suppressing sulfation... the lead sulfate obtains the electrons and changes to metallic lead in a charge reaction. When the lead sulfate becomes coarsened, the lead sulfate is hardly dissolved in the charge reaction
Data Source
AI summary
An organic expander for a lead storage battery includes sulfomethylated kraft lignin, wherein an organic S content contained in the sulfomethylated kraft lignin is more than 3.8 mass % and 5.1 mass % or less.