High-Density Lead Lanthanum Zirconium Titanate Dielectric for Capacitors
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Solution Overview
Problem
Conventional capacitors for electric vehicle traction motors face malfunctions at high temperatures due to polymer insulators and have issues with dielectric constant degradation at high voltages, leading to increased size and weight with heat-blocking materials, and decreased performance with barium titanate at high voltages.
Innovation Solution
A method of manufacturing a high-density dielectric for capacitors using a precursor mixture of lead oxide, lanthanum oxide, zirconium oxide, and titanium oxide, calcined and sintered at low temperatures with additives like sodium and potassium to achieve a high dielectric constant and stability at high voltages and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If barium titanate is used as dielectric material, then dielectric constant and capacitance are improved, but dielectric constant decreases at high voltage
Solution Approach 1:
The patent uses a composite dielectric material composed of Pb(La,Zr,Ti)O3 with specific compositional ratios (La: 0.05-0.15 mol ratio, Zr: 0.40-0.60 mol ratio, Ti: 0.20-0.35 mol ratio) to achieve both high dielectric constant and stability at high voltage. The composite structure combines the advantages of different oxide components to maintain performance under high voltage conditions while avoiding the degradation issue of pure barium titanate.
2Manufacturing precision
If conventional high-temperature sintering is used, then dielectric density is improved, but manufacturing cost and energy consumption increase
Solution Approach 1:
The patent optimizes the sintering temperature parameter to a specific range (900-1100°C) that achieves high dielectric density (≥7.5 g/cm³) without requiring excessively high temperatures. This parameter optimization, combined with controlled sintering time (2-5 hours), resolves the contradiction between achieving high density and reducing energy consumption.
3Ease of manufacture
If polymer film is used as insulator, then ease of manufacture is improved, but reliability at high temperature deteriorates
Solution Approach 1:
The patent transitions from polymer film to ceramic dielectric material, changing the material parameter to achieve high-temperature reliability. The ceramic dielectric with optimized composition maintains its dielectric properties at high temperatures, resolving the reliability issue while the manufacturing process remains feasible through standard ceramic processing techniques.
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 method produces a dielectric with a dielectric constant of 800 or higher and a density of 7.5 g/cm3, enabling stable operation at high voltages and temperatures with a reduced sintering temperature and increased production yield.
Implementation Method 1
calcining the precursor mixture to produce a calcined product
Implementation Method 2
sintering the molded product to produce a sintered product
Data Source
AI summary
A method of manufacturing a dielectric for a capacitor and a dielectric for a capacitor manufactured thereby are provided. A dielectric for a capacitor is prepared by calcining a precursor mixture containing lead, lanthanum, zirconium, and titanium to produce calcined powder, adding additives including sodium, potassium, and the like to the powder, and sintering the mixture at a low temperature, whereby the dielectric has a high density and a large dielectric constant.