Lead-Acid Battery Electrode Design for Idling Stop Durability
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Solution Overview
Problem
Lead-acid batteries used in idling stop vehicles face challenges with insufficient charge acceptance and reduced durability due to frequent discharging and recharging, leading to premature sulfation and activation of fail-safe mechanisms, especially in short-distance drive modes.
Innovation Solution
A lead-acid battery design featuring positive and negative electrode grids made of lead or lead alloys without antimony, with surface layers of lead alloys containing antimony, and optimized mass ratios and electrolyte compositions to enhance charge acceptance and durability, including sodium ions and specific structural configurations to improve charge recovery and reduce fail-safe mechanism activation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a lead-acid battery supplies power to all of an air conditioner, a fan, etc. during idling stop, then the vehicle can operate air conditioning systems during engine off periods, but the lead-acid battery is likely to be in an insufficiently-charged state
Solution Approach 1:
The patent changes the chemical composition parameters of the battery by adding aluminum ions to the electrolyte and using specific lead alloys (Pb-Ca-Al-Sn for positive electrode, Pb-Al-Sn for negative electrode) to improve charge acceptance and reduce sulfation during frequent idling stop cycles
Solution Approach 2:
The patent employs composite material structures including lead alloys with multiple elements (Ca, Al, Sn) in both electrodes and aluminum ions in the electrolyte, creating a multi-component system that enhances both power delivery capability and charge acceptance during idling stop operations
2Productivity
If the idling stop vehicle frequently repeats ON/OFF of the engine, then the vehicle can reduce fuel consumption by turning off the engine during stops, but succeeding discharging is performed before lead dioxide and lead are recovered from lead sulfate generated by preceding discharging
Solution Approach 1:
The patent modifies the electrolyte composition by adding aluminum ions and adjusts electrode material parameters using specific lead alloys to accelerate the recovery of lead dioxide and lead from lead sulfate, enabling the battery to withstand frequent discharge cycles without premature sulfation
Solution Approach 2:
The patent converts the harmful effect of frequent discharging that causes sulfation into a beneficial outcome by using aluminum ions and specific lead alloys that promote rapid conversion of lead sulfate back to active materials, thereby extending battery life while maintaining fuel economy benefits of idling stop
3Reliability
If the mass ratio of the negative electrode active material to a positive electrode active material falls within a range of 0.7 to 1.3, then elution of the antimony from the negative electrode active material to the electrolyte can be reduced, but the charge acceptance may be compromised
Solution Approach 1:
The patent optimizes the mass ratio parameter of negative to positive electrode active materials to within 0.7-1.3, and further refines it to 0.85-1.15 in the improved embodiment, while simultaneously changing the chemical composition by using antimony-free lead alloys and adding aluminum ions to achieve both reduced antimony elution and improved charge acceptance
Solution Approach 2:
The patent applies different material compositions to different electrodes: the positive electrode uses Pb-Ca-Al-Sn alloy while the negative electrode uses Pb-Al-Sn alloy without antimony, creating local quality differences that optimize both charge acceptance and reduce harmful elution effects
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 provides lead-acid batteries with improved charge acceptance, durability, and charge recovery, effectively reducing the frequency of fail-safe mechanism activation and extending the battery life in idling stop vehicles, especially in short-distance drive modes.
Implementation Method 1
The aluminum ions exhibit the effect of reducing, in discharging, coarsening of lead sulfate generated at positive and negative electrodes, thereby improving the charge acceptance of the lead-acid battery
Implementation Method 2
The lead alloy layer containing antimony exhibits the effect of efficiently performing charge recovery of a negative electrode plate, thereby improving the durability of the lead-acid battery
Implementation Method 3
The antimony added to the negative electrode active material exhibits the effect of decreasing a hydrogen overvoltage of a negative electrode, thereby improving the charge acceptance of the negative electrode active material
Data Source
AI summary
In a lead-acid battery including an electrode plate group housed in a cell chamber 6 with an electrolyte, each positive electrode plate includes a positive electrode grid made of lead or a lead alloy containing no antimony, and a positive electrode active material with which the positive electrode grid is filled. Each negative electrode plate includes a negative electrode grid made of lead or a lead alloy containing no antimony, a surface layer formed on a surface of the negative electrode grid and made of a lead alloy containing antimony, and a negative electrode active material with which the negative electrode grid is filled. A mass ratio MN/MP falls within a range of 0.70 to 1.10, where MP represents the mass of the positive electrode active material per cell chamber, and MN represents the mass of the negative electrode active material per cell chamber.