Hollow Cathode Active Material for Low-Temperature Battery Output
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Solution Overview
Problem
Conventional techniques for non-aqueous electrolyte secondary batteries face challenges in achieving high output characteristics while preventing gelation during paste preparation, due to issues with lithium elution and crystallinity of the positive electrode active material.
Innovation Solution
A lithium-metal composite oxide powder is developed with a specific particle size and structure, including a hollow secondary particle configuration, optimized pH, and controlled porosity, which is manufactured through a process involving pulverization of lithium compounds and firing with metal composite hydroxides, to enhance reactivity and prevent lithium elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water washing is performed to remove excessive lithium, then initial discharge capacity and thermal stability are improved, but the surface of the lithium-metal composite oxide is damaged and lithium is eluted to deteriorate output characteristic
Solution Approach 1:
The patent extracts and removes excessive lithium from the surface of the lithium-metal composite oxide through water washing, thereby improving thermal stability and initial discharge capacity while minimizing damage to the oxide surface and lithium elution
Solution Approach 2:
The patent optimizes washing parameters including water temperature, washing time, and water-to-oxide ratio to achieve effective removal of excessive lithium while minimizing surface damage and lithium elution, thereby balancing thermal stability improvement with output characteristic preservation
2Power
If fine particles are used to increase specific surface area, then output characteristic is improved, but a large amount of conductive agent must be added which reduces energy density
Solution Approach 1:
The patent applies local quality by selectively adding conductive agents only to specific regions or surfaces of the fine particles where needed for conductivity, rather than uniformly distributing conductive agents throughout the entire material, thereby reducing the total amount of conductive agent required while maintaining output characteristic
Solution Approach 2:
The patent creates composite materials by combining fine particles with conductive agents in optimized ratios and configurations, forming a composite structure that enhances conductivity at the particle level while minimizing the overall conductive agent content to preserve energy density
3Power
If low thermal treatment temperature is applied to increase specific surface area, then output characteristic is improved, but reactivity between lithium source and metal hydroxide decreases and crystallinity is deteriorated
Solution Approach 1:
The patent performs preliminary actions before thermal treatment, including optimizing the mixing of lithium source and metal hydroxide, controlling particle size distribution, and preparing the precursor materials in advance, which enables effective reaction and crystallization even at lower thermal treatment temperatures, thereby improving output characteristic while maintaining crystallinity
Solution Approach 2:
The patent optimizes multiple parameters including thermal treatment temperature, holding time, atmosphere composition, and precursor ratio to achieve the desired balance between increasing specific surface area for improved output characteristic and maintaining sufficient reactivity and crystallinity for stable composition
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 enables high output characteristics at low temperatures without water washing, suppresses soluble lithium generation, and prevents gelation during paste preparation, resulting in improved battery performance.
Implementation Method 1
pulverization of lithium compounds
Implementation Method 2
firing with metal composite hydroxides
Implementation Method 3
firing with metal composite hydroxides to form lithium-metal composite oxide
Implementation Method 4
a secondary particle configured by aggregating primary particles
Data Source
AI summary
The present invention provides a composite oxide that can achieve a high low-temperature output characteristic, a method for manufacturing the same, and a positive electrode active material in which the generation of soluble lithium is suppressed and a problem of gelation is not caused during the paste preparation. A positive electrode active material for non-aqueous electrolyte secondary batteries, including a lithium-metal composite oxide powder including a secondary particle configured by aggregating primary particles containing lithium, nickel, manganese, and cobalt, or a lithium-metal composite oxide powder including both the primary particles and the secondary particle, wherein the secondary particle has a hollow structure inside as a main inside structure, the slurry pH is 11.5 or less, the soluble lithium content rate is 0.5 [% by mass] or less, the specific surface area is 2.0 to 3.0 [m2/g], and the porosity is 20 to 50 [%].