Lead-Acid Battery Electrode Composition for Cycle-Stable Cold Discharge
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Solution Overview
Problem
Lead-acid batteries experience a decrease in low-temperature high-rate discharge performance due to the elution of organic expanders from the negative electrode material and corrosion of the positive current collector during charge-discharge cycles, especially in high-temperature environments, leading to a reduction in the reaction area and specific surface area.
Innovation Solution
A lead-acid battery design incorporating a positive current collector with a lead alloy containing Ca and Sn, where Ca is 0.2% by mass or less and Sn is 0.5% by mass or more, and a negative electrode material with a first organic expander excluding lignin compounds, featuring a monocyclic aromatic compound or bisphenol S unit, which enhances adsorptivity and suppresses elution, thereby maintaining the specific surface area and reaction area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic expander is added to negative electrode material, then low-temperature high-rate discharge performance is improved, but organic expander is gradually eluted during charge-discharge cycles causing performance degradation
Solution Approach 1:
The patent uses a composite organic expander system combining two different organic expanders with complementary functions. The first organic expander provides initial expansion and performance, while the second organic expander with higher sulfur content (more than 800 μmol/g) provides long-term stability and prevents elution. This composite approach allows the battery to maintain low-temperature high-rate discharge performance throughout charge-discharge cycles by leveraging the synergistic effects of both expanders.
Solution Approach 2:
The patent changes the chemical composition parameters of the organic expander by selecting compounds with specific sulfur content ranges. The second organic expander is chosen to have sulfur content of more than 800 μmol/g, which correlates with better thermal stability and reduced elution. This parameter optimization ensures the expander maintains its function during high-temperature charging cycles, thereby preserving performance after cycling.
2Duration of action of stationary object
If positive current collector undergoes corrosion during charge-discharge cycle, then reaction area of positive electrode plate decreases, but this also reduces reaction area of negative electrode plate
Solution Approach 1:
The patent optimizes the alloy composition parameters of the positive current collector by controlling calcium content to 0.2% by mass or less and tin content to 0.5% by mass or more. This specific compositional parameter range minimizes corrosion rate during charge-discharge cycles while maintaining electrical conductivity and structural integrity, thereby preserving the reaction area of both positive and negative electrode plates throughout the battery's service life.
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 solution effectively suppresses the decrease in low-temperature high-rate discharge performance after charge-discharge cycles, improving the battery's durability and performance by maintaining the specific surface area and reaction area of the negative electrode material.
Implementation Method 1
a negative electrode material contains a first organic expander (excluding a lignin compound) containing at least one selected from the group consisting of a unit of a monocyclic aromatic compound and a unit of a bisphenol S compound
Data Source
AI summary
A lead-acid battery includes a positive electrode plate, a negative electrode plate, and an electrolyte solution. The positive electrode plate includes a positive current collector and a positive electrode material. The negative electrode plate includes a negative current collector and a negative electrode material. The positive current collector contains a lead alloy containing Ca and Sn. The content of Ca in the positive current collector is 0.2% by mass or less, and the content of Sn is 0.5% by mass or more. The negative electrode material contains a first organic expander (excluding a lignin compound) containing at least one selected from the group consisting of a unit of a monocyclic aromatic compound and a unit of a bisphenol S compound.