Rolled Expanded Lead Plates for Battery Weight Reduction
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Solution Overview
Problem
Conventional lead-acid batteries face challenges with weight reduction, corrosion resistance, and lifespan due to the use of gravity casting processes, which result in dense metal structures and increased manufacturing costs, while also experiencing electrolyte consumption and gas leakage issues.
Innovation Solution
The use of rolled expanded lead plates with absorbent glass mat (AGM) separators and a rubber valve system to manage gas pressure, reducing plate weight, enhancing corrosion resistance, and maintaining electrolyte levels, while allowing gas exhaustion at predetermined pressure levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gravity casting process is used to manufacture lead plates, then manufacturing precision is improved, but weight increases and manufacturing cost increases
Solution Approach 1:
The patent changes the manufacturing parameters from gravity casting to rolling and expanding processes. The lead plates are manufactured by rolling lead ingots at high temperatures and then expanding them to create the grid structure, which reduces material usage while maintaining structural integrity and thickness uniformity through controlled rolling parameters.
Solution Approach 2:
The patent employs a porous grid structure manufactured by the rolling and expanding process. The expanding step creates a three-dimensional porous network that reduces the amount of lead material needed compared to solid cast plates, thereby reducing weight while maintaining sufficient mechanical strength and electrical conductivity.
2Manufacturing precision
If gravity casting process is used to manufacture lead plates, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the manufacturing process parameters from precision gravity casting to a combination of rolling and expanding processes. The rolling process uses high temperature (400-500°C) to reduce flow stress and enable formability, while the expanding process creates the grid structure in one operation, reducing the number of manufacturing steps and associated costs.
Solution Approach 2:
The patent adopts a manufacturing approach that uses readily available lead ingots and simple rolling/expanding equipment rather than expensive precision casting molds and machinery. The process is more tolerant of material variations and equipment simplicity, reducing capital investment and operational costs.
3Strength
If conventional lead plates are used, then structural strength is maintained, but corrosion resistance decreases
Solution Approach 1:
The patent applies local quality by creating a specific surface structure through the expanding process. The expansion creates a porous network with controlled pore sizes and distributions that provide better corrosion resistance in critical areas while maintaining overall structural strength. The grid intersections and struts have optimized thickness ratios that balance strength and corrosion resistance.
Solution Approach 2:
The patent effectively creates a composite structure by forming a porous lead matrix with controlled void spaces. This porous composite structure provides both mechanical strength from the lead framework and corrosion resistance from the reduced surface area exposed to electrolyte and the beneficial pore structure that facilitates protective oxide formation.
4Object-generated harmful factors
If gas outlet is provided in closed battery case, then gas exhaustion is enabled, but electrolyte consumption increases
Solution Approach 1:
The patent uses a rubber valve membrane that can flex and seal. The membrane remains sealed under normal operating conditions to prevent electrolyte evaporation and gas leakage, but automatically opens when gas pressure exceeds a threshold, allowing gas relief without significant electrolyte loss. The flexibility of the rubber material enables it to respond dynamically to pressure changes.
Solution Approach 2:
The rubber valve provides self-regulating gas pressure relief. It automatically opens when internal gas pressure exceeds the sealing force of the rubber membrane, and automatically closes when pressure equalizes, without requiring external control or intervention. This self-service mechanism prevents both over-pressurization and excessive electrolyte loss.
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 results in a lighter, longer-lasting battery with improved corrosion resistance, reduced manufacturing costs, and increased energy density, effectively addressing the limitations of conventional lead-acid batteries.
Implementation Method 1
absorbent glass mat (AGM) separators
Implementation Method 2
a rubber valve, decreasing the consumption of an electrolyte, preventing corrosion of the plates, and increasing the charge rate of the battery
Data Source
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AI summary
The present invention comprises: a plurality of anode plates, formed as a mesh by forming a plurality of cuts in series on a lead plate strip rolled into a uniform thickness, for storing electricity in a chemically reactive state by means of expansion processing; a plurality of cathode plates formed as a mesh for storing electricity in a chemically reactive state; a plurality of separators disposed between the anode and cathode plates for electrical insulation, mechanical separation, and the impregnation of an AGM with electrolyte, such that the chemical reaction for storing electricity is facilitated and the pressure in the cell remains constant; upper and lower cases made of polypropylene and containing the anode plates, cathode plates, separators, and electrolyte in a plurality of mutually separate cells; and a cap coupled into the screw holes formed in the cell units in the upper case, for discharging gas generated during charge and discharge when the pressure of the gas is at or over a permissible level.