Lead Storage Battery Negative Electrode Composition for Low SOC
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Solution Overview
Problem
Lead storage batteries used in vehicles with stop-and-go and regenerative-braking systems face reduced service life due to frequent charge/discharge cycles at low state of charge (SOC), leading to electrolyte depletion, negative electrode grid corrosion, and decreased chargeability.
Innovation Solution
A lead storage battery design incorporating Pb-alloys with Ca and Sn for positive and negative electrode grids, along with a negative electrode active material layer containing Sb and a bisphenol-aminobenzene sulfonic acid derivative, and an acid-resistant separator, to enhance chargeability and prevent electrolyte loss and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If frequent charge/discharge cycles are performed at low SOC to meet stop-and-go and regenerative-braking system requirements, then the battery can support these vehicle systems, but service life is reduced due to electrolyte depletion and electrode degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the electrode materials by incorporating specific amounts of Sb (0.01-3 wt%) and Sn (0.1-5 wt%) in the negative electrode, and Sb (0.01-5 wt%) and Sn (0.1-5 wt%) in the positive electrode. These compositional parameter changes improve the battery's adaptability to frequent charge/discharge cycles at low SOC while mitigating electrolyte depletion and electrode degradation, thereby extending service life
Solution Approach 2:
The patent uses composite electrode materials combining Pb with multiple alloying elements (Sb, Sn, Ca, Al) in specific proportions. This composite material approach creates a synergistic effect where the combination of elements provides both the adaptability needed for stop-and-go systems and the durability required for long service life, resolving the contradiction between system adaptability and reliability
2Productivity
If SOC is maintained at low levels (50-90%) to enable regenerative braking energy storage, then regenerative energy can be captured, but chargeability deteriorates due to negative electrode plate degradation
Solution Approach 1:
The patent modifies the chemical composition parameters of the negative electrode active material by adding Sb (0.01-3 wt%) and Sn (0.1-5 wt%), which change the electrochemical properties of the electrode. These parameter changes improve chargeability by reducing hydrogen overvoltage and preventing dendrite formation, enabling the battery to maintain good charge acceptance even when operated at low SOC ranges for regenerative braking
Solution Approach 2:
The alloying elements Sb and Sn act as intermediaries in the electrochemical reactions at the negative electrode. They mediate between the Pb active material and the electrolyte, reducing the harmful effects of low SOC operation on chargeability while still allowing regenerative energy storage functionality
3Device complexity
If constant voltage control is used for charging, then charging simplicity is maintained, but insufficient charge occurs when negative electrode chargeability decreases
Solution Approach 1:
The patent applies preliminary action by pre-alloying the negative electrode with Sb and Sn elements before battery operation. This preliminary compositional modification prevents chargeability deterioration from occurring in the first place, so that simple constant voltage charging can continue to provide sufficient charge throughout the battery's service life without requiring complex charging control systems
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 extends the service life and reliability of lead storage batteries by improving chargeability and preventing electrolyte depletion and corrosion, even under over-discharge conditions, resulting in a longer-lasting and maintenance-free battery.
Implementation Method 1
a part of Sb which exists on a surface of the positive electrode grid dissolves in an electrolyte, and deposits on a negative electrode plate
Implementation Method 2
After starting an engine, a lead storage battery is charged by an alternator
Implementation Method 3
in the regenerative-braking-system, a kinetic energy of a vehicle at the time of deceleration is converted to an electric energy, and the electric energy is stored
Data Source
AI summary
A lead storage battery of the present invention has: an electrode plate pack including a plurality of negative electrode plates which each comprise a negative electrode grid having a tab and a negative electrode active material layer retained by the negative electrode grid, a plurality of positive electrode plates which each comprise a positive electrode grid having a tab and a positive electrode active material layer retained by the positive electrode grid, and a plurality of separators separating the positive and negative electrode plates; a positive electrode connecting member connected to each positive electrode plate of the electrode plate pack; and a negative electrode connecting member connected to each negative electrode plate of the electrode plate pack. The negative electrode active material layer includes 0.0001 to 0.003 wt % of Sb, and includes 0.01 to 2 wt % of a condensate of bisphenol and aminobenzene sulfonic acid derivative.