Lead-Acid Battery Negative Electrode Anti-Shrink Agent
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Solution Overview
Problem
The existing lead-acid batteries face challenges in maintaining high rate discharge performance at low temperatures and durability due to the aggregation of lignosulfonic acid in sulfuric acid, which affects the pore size of the negative electrode material, leading to reduced performance when exposed to high temperatures.
Innovation Solution
Incorporating an organic anti-shrink agent with a controlled average particle size of not less than 0.1 μm and not more than 9 μm in sulfuric acid, specifically lignosulfonic acid or its derivatives, to optimize the pore size of the negative electrode material, thereby enhancing initial high rate discharge performance and reducing deterioration at low temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lignosulfonic acid is used as an organic anti-shrink agent in a lead-acid battery, then high rate discharge performance at low temperature is improved, but the battery performance deteriorates when exposed to high temperatures due to aggregation of lignosulfonic acid in sulfuric acid
Solution Approach 1:
The patent applies parameter changes by controlling the average particle size of lignosulfonic acid within a specific range (0.01 to 0.8 μm) and adjusting the sulfonation ratio (6 to 10 mass% S element content). These parameter optimizations prevent excessive aggregation in sulfuric acid while maintaining the anti-shrink effect, thereby resolving the contradiction between low-temperature performance and high-temperature stability.
Solution Approach 2:
The patent uses composite materials by combining lignosulfonic acid with a sulfonic acid salt of a styrene-divinylbenzene copolymer (cation exchange resin). This composite approach leverages the chemical stability of the copolymer to counteract the aggregation tendency of lignosulfonic acid in sulfuric acid, maintaining both low-temperature discharge performance and high-temperature durability.
2Reliability
If the sulfonation ratio of lignin sulfonic acid is increased to 90% or more, then variations in high rate discharge performance at low temperature are reduced, but charge acceptability deteriorates due to excessive Pb2+ ion adsorption
Solution Approach 1:
The patent applies parameter changes by optimizing the sulfonation ratio to a specific range (6 to 10 mass% S element content, equivalent to approximately 1875 to 3125 μmol/g). This optimized parameter range prevents excessive Pb2+ ion adsorption that would harm charge acceptability, while still maintaining sufficient consistency in high rate discharge performance at low temperatures.
3Reliability
If lignosulfonic acid with small average particle size is used, then high rate discharge performance at low temperature is improved, but the anti-shrink effect is reduced
Solution Approach 1:
The patent applies parameter changes by controlling the average particle size of lignosulfonic acid within the optimal range of 0.01 to 0.8 μm. This parameter optimization balances the competing requirements: small enough particle sizes to maintain high rate discharge performance at low temperatures, while large enough to provide sufficient anti-shrink effect in the negative electrode material.
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 controlled particle size of the organic anti-shrink agent improves the initial high rate discharge performance at low temperatures and maintains performance even after exposure to high temperatures, reducing the reduction in discharge capacity and increasing the durability of the lead-acid battery.
Implementation Method 1
lignosulfonic acid is aggregated in sulfuric acid, and thus has a larger particle size in sulfuric acid than in neutral water
Implementation Method 2
The negative electrode material contains an organic anti-shrink agent... lignosulfonic acid or a sulfonated bisphenol condensation product
Data Source
AI summary
A negative electrode material contains an organic anti-shrink agent which is soluble in water, and the organic anti-shrink agent, when extracted from the negative electrode material with an alkali aqueous solution, has an average particle size of not less than 0.1 μm and not more than 9 μm in sulfuric acid having a specific gravity of 1.25. A lead-acid battery includes a negative electrode plate containing an organic anti-shrink agent having a S element content of 4000 μmol/g or more. The negative electrode contains 0.3 mg/cm3 or more of the S element in the organic anti-shrink agent.