Lead-Acid Battery Negative Electrode Polymer for Overcharge Control
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Solution Overview
Problem
Existing lead-acid batteries face a trade-off between suppressing charge acceptability deterioration and reducing the amount of overcharge, as organic additives on the lead surface hinder reductive hydrogen ion reactions and lead sulfate elution, leading to inhibited charge-discharge reactions and low temperature performance.
Innovation Solution
Incorporating a polymer compound with a specific chemical shift of 3.2-3.8 ppm in the negative electrode material, maintaining a Cn/Sn ratio of 25 ppm·m−2·g or more, which covers the lead surface thinly and enhances hydrogen overvoltage, inhibiting side reactions and promoting ion movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If organic additive is added to negative electrode plate active material, then amount of overcharge decreases, but charge acceptability deteriorates
Solution Approach 1:
The patent changes the chemical structure parameters of the organic additive by specifying a polymer compound with particular NMR chemical shift characteristics (3.2-3.8 ppm range) and controlling the Cn/Sn ratio parameter at 25 ppm·m−2·g or more. This parameter optimization allows the additive to form a thin surface coverage that suppresses hydrogen evolution while maintaining lead sulfate elution capability.
Solution Approach 2:
The patent creates a composite negative electrode material comprising lead or lead alloy particles combined with a specific polymer compound. This composite structure enables the polymer to function as a surface-modifying agent that simultaneously achieves overcharge suppression and charge acceptability maintenance through its unique molecular structure and controlled content ratio.
2Object-generated harmful factors
If lead surface is covered with organic additive, then reductive reaction of hydrogen ions is suppressed, but lead sulfate elution during charge is hindered
Solution Approach 1:
The patent optimizes the coverage parameter by controlling the polymer compound content (Cn/Sn ratio) to be 25 ppm·m−2·g or more, which creates a thin surface layer that is sufficient to suppress hydrogen ion reduction but thin enough to allow lead sulfate elution. The specific NMR chemical shift range (3.2-3.8 ppm) serves as a parameter to identify polymers with appropriate molecular structure for this dual function.
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 reduces overcharge while maintaining charge acceptability and low temperature discharge performance, prolonging battery life by suppressing structural changes and hydrogen generation.
Implementation Method 1
the polymer compound has a peak in a range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of 1H-NMR spectrum, and a ratio: Cn/Sn of a content Cn of the polymer compound in the negative electrode material to a specific surface area Sn of the negative electrode material is 25 ppm·m−2·g or more
Implementation Method 2
covers the lead surface thinly and enhances hydrogen overvoltage, inhibiting side reactions
Implementation Method 3
promoting ion movement
Implementation Method 4
Lead-acid batteries include a negative electrode plate, a positive electrode plate, a separator (or mat), an electrolyte solution
Implementation Method 5
charge acceptability deterioration and reducing the amount of overcharge
Data Source
AI summary
A lead-acid battery includes a positive electrode plate, a negative electrode plate, and an electrolyte solution. The negative electrode plate includes a negative electrode material. The negative electrode material contains a polymer compound, and the polymer compound has a peak in a range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of 1H-NMR spectrum. Alternatively, the negative electrode material contains a polymer compound having a repeating structure of oxy C2-4 alkylene units. A ratio: Cn/Sn of a content Cn of the polymer compound in the negative electrode material to a specific surface area Sn of the negative electrode material is 25 ppm·m−2·g or more.