Lithium Hydroxide Powder Storage to Suppress Carbonation
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Solution Overview
Problem
Lithium hydroxide easily reacts with carbon dioxide in the atmosphere to form lithium carbonate, which can contaminate positive electrode active materials in lithium secondary batteries, leading to battery swelling and performance issues.
Innovation Solution
A method involving the pulverization of lithium hydroxide followed by storage in an airtight container with controlled carbon dioxide partial pressure (100 Pa or less) and relative humidity (60% or less), or using a circulating gas with low carbon dioxide concentration, to suppress the formation of lithium carbonate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If lithium hydroxide is stored in the atmosphere, then it is easily accessible and convenient for use, but it reacts with carbon dioxide to form lithium carbonate impurities
Solution Approach 1:
The patent applies the inert atmosphere principle by storing lithium hydroxide in containers filled with nitrogen gas or other inert gases that have low reactivity with lithium hydroxide. This prevents the carbonation reaction while maintaining ease of storage and handling. The inert gas creates a protective environment that eliminates the harmful interaction between atmospheric carbon dioxide and lithium hydroxide.
Solution Approach 2:
The patent extracts the harmful carbon dioxide component from the storage environment by using airtight containers that exclude atmospheric air. This separation removes the source of the harmful reaction (carbon dioxide) from contact with lithium hydroxide, thereby preserving purity while maintaining operational convenience.
2Ease of manufacture
If lithium hydroxide is pulverized to fine powder, then it has better reactivity and processing characteristics, but it has larger surface area that accelerates carbonation
Solution Approach 1:
The patent applies inert atmosphere protection during storage of the pulverized lithium hydroxide powder. By storing the fine powder in nitrogen-filled or airtight containers, the large surface area is protected from atmospheric carbon dioxide, preventing accelerated carbonation while maintaining the beneficial reactivity and processing characteristics of the fine powder form.
Solution Approach 2:
The patent performs pulverization immediately before use rather than storing the fine powder for extended periods. This preliminary action approach minimizes the time that the high-surface-area powder is exposed to atmospheric carbon dioxide, thereby reducing carbonation while still achieving the desired reactivity and processing characteristics when needed.
3Duration of action of stationary object
If lithium hydroxide is stored for extended periods, then it is ready for future use, but carbonation accumulates over time
Solution Approach 1:
The patent uses inert atmosphere storage (nitrogen gas filling or airtight sealing) to enable extended storage of lithium hydroxide without significant carbonation. The inert environment prevents the time-dependent accumulation of lithium carbonate impurities, allowing the material to be stored for long periods while maintaining low impurity levels and high purity.
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 method effectively reduces the generation of lithium carbonate, resulting in a lithium hydroxide powder with low impurity content, which improves the performance and stability of lithium secondary batteries by minimizing electrolysis during charging.
Implementation Method 1
lithium hydroxide reacts with carbon dioxide in the atmosphere to undergo carbonation and easily changes to lithium carbonate
Data Source
AI summary
A method for manufacturing a lithium hydroxide powder includes a pulverizing step of pulverizing coarse particles of lithium hydroxide to obtain lithium hydroxide powder; and a carbonation-suppressing step of storing the lithium hydroxide powder in an airtight container in an atmosphere satisfying requirements (1) and (2).(1) A partial pressure of carbon dioxide gas is 100 Pa or less with respect to a total amount of gas present in the airtight container.(2) A relative humidity in the airtight container is 60% or less.