Hybrid Electrode with Conductive Mat for Lead-Acid Battery
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Solution Overview
Problem
Current lead-acid batteries used in electric vehicles and hybrid electric vehicles face premature failure due to the formation of lead sulphate on the negative plate surfaces, leading to reduced effective surface area and lifespan, especially under high-rate partial state-of-charge conditions.
Innovation Solution
The development of an electrode for electrical storage devices comprising a current collector, a high-energy electroactive material, a high-rate electroactive material, and an electrically conductive mat, where the high-energy material has higher energy density and the high-rate material has higher rate capability, with the conductive mat providing structural and conductive support to prevent shedding and enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lead-acid batteries operate under high-rate partial state-of-charge conditions, then high current demand is met for acceleration and regenerative braking, but lead sulphate accumulates on negative plate surfaces causing premature failure
Solution Approach 1:
The negative electrode is segmented into multiple functional layers: a current collector, a first electroactive material layer (sponge lead or lead alloy) for high energy density, a second electroactive material layer (carbon-based material) for high rate capability, and an electrically conductive mat for structural support. This segmentation allows each layer to perform its specific function, preventing lead sulphate accumulation while maintaining high current output.
Solution Approach 2:
The electrode uses composite materials combining different electroactive materials with complementary properties. The first electroactive material (lead-based) provides high energy density, while the second electroactive material (carbon-based) provides high rate capability and prevents lead sulphate formation. The electrically conductive mat (carbon fibre or metal mesh) provides both structural support and electrical conductivity, creating a composite structure that resolves the contradiction between power and reliability.
2Power
If the effective surface area of the negative plate is reduced by lead sulphate accumulation, then the battery can no longer deliver higher current, but increasing surface area does not prevent sulphate formation
Solution Approach 1:
Different regions of the electrode have different local qualities tailored to specific functions. The inner layer (first electroactive material) provides high energy density, while the outer layer (second electroactive material) provides high rate capability and sulphate resistance. The electrically conductive mat provides localized structural support and conductivity enhancement at critical interfaces, ensuring current delivery without sulphate-induced surface area loss.
Solution Approach 2:
The second electroactive material (carbon-based) acts as an intermediary between the lead-based electroactive material and the electrolyte. This intermediary layer prevents direct contact between lead sulphate and the electrolyte, blocking sulphate formation while maintaining electrical conductivity and surface area for high current delivery.
3Power
If hybrid electrodes combine electroactive capacitor with electrochemical battery, then peak power requirements are met, but various problems still limit overall performance and cycle life
Solution Approach 1:
The invention merges capacitor and battery functionalities into a single integrated electrode structure. The first electroactive material (lead-based) provides battery-like high energy density, while the second electroactive material (carbon-based) provides capacitor-like high rate capability. The electrically conductive mat binds these materials together, creating a unified hybrid electrode that delivers both peak power and long cycle life without the performance limitations of previous hybrid designs.
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 proposed electrode configuration significantly improves the cycle life and performance of lead-acid batteries by maintaining structural integrity and conductivity, reducing shedding of materials during high-rate charging and discharging, and extending the battery's lifespan.
Implementation Method 1
a first electroactive material; a second electroactive material; wherein: the first electroactive material has a higher energy density than the second electroactive material, and the second electroactive material has a higher rate capability than the first electroactive material
Implementation Method 2
an electrically conductive mat; wherein the electrically conductive mat provides structural and conductive support for at least one of the first electroactive material and the second electroactive material
Data Source
AI summary
The present invention generally relates to electrodes, electrical storage devices comprising the electrodes, and methods for producing the electrodes and electrical storage devices. The electrodes comprise a current collector, an electrically conductive mat, and a first and second electroactive material, the first electroactive material having a higher energy density than the second electroactive material, and the second electroactive material having a higher rate capability than the first electroactive material. The electrically conductive mat provides a structural and conductive support for at least one of the high-rate and high-energy electroactive materials. The electrodes can be provided in various configurations and be used in high-rate high-energy electrical storage devices to provide improved cycle life.