Cathode Active Material Heat Treatment Suppresses Battery Swelling
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Solution Overview
Problem
Lithium rechargeable batteries experience swelling issues at high temperatures due to gas generation at the interface between the cathode and electrolytic solution, which can damage electronic devices, and existing solutions that limit carbonate and water concentrations are insufficient in preventing this issue.
Innovation Solution
A cathode active material with a carbonate ion concentration of 0.5% by weight or less and hydroxyl ion concentration of 0.1% by weight, which reduces the oxidation of these ions and subsequent gas generation, thereby minimizing battery expansion even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the battery is used at high temperatures (60°C or more), then the battery can operate in hot environments, but gas is generated at the cathode-electrolyte interface causing battery swelling
Solution Approach 1:
The cathode active material is pre-treated through a specific heat treatment process (heating at 50-100°C for 1-48 hours in a vacuum or inert atmosphere) before battery assembly. This preliminary action removes adsorbed water and prevents carbonate formation on the cathode surface, so that when the battery operates at high temperatures, there is no water-catalyzed decomposition of carbonate solvents to generate gas.
Solution Approach 2:
The invention changes the physical-chemical parameters of the cathode active material by controlling its moisture content and surface composition through heat treatment. By reducing the water content to 0.03% or less and preventing carbonate formation, the chemical reactivity at the cathode-electrolyte interface is modified, preventing the harmful gas generation reaction that would otherwise occur at high operating temperatures.
2Reliability
If carbonate and water concentrations are limited (as suggested in prior art), then some gas generation is reduced, but batteries still swell at high temperatures when charged
Solution Approach 1:
The cathode active material undergoes preliminary heat treatment in a vacuum or inert atmosphere before battery assembly, which removes adsorbed water and prevents carbonate formation. This preliminary action addresses the root cause (water presence) rather than just limiting the consequences (carbonate concentration), making the battery reliable even at high temperatures during charging.
Solution Approach 2:
The invention extracts and removes the harmful element (water) from the cathode active material through heat treatment before assembly. By taking out the water that catalyzes the decomposition reaction, the battery achieves stability at high temperatures without relying merely on limiting carbonate concentrations in the electrolyte.
3Object-affected harmful factors
If the cathode active material is heat treated to remove water and prevent carbonate formation, then gas generation is reduced, but additional manufacturing steps are required
Solution Approach 1:
The heat treatment is performed as a preliminary action during the cathode material preparation stage, before battery assembly. By incorporating this step early in the manufacturing process when the cathode material is still in powder form, the treatment is efficient and integrates well into existing production workflows, minimizing additional complexity.
Solution Approach 2:
The invention uses controlled parameter changes (temperature, time, atmosphere) during heat treatment to achieve the desired reduction in water content and prevention of carbonate formation. By optimizing these parameters (50-100°C for 1-48 hours in vacuum or inert atmosphere), the process becomes efficient and scalable, reducing gas generation without excessive manufacturing complexity.
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 cathode active material effectively maintains battery thickness expansion at 25% or less at 85°C for 4 hours, ensuring the battery's usability in portable electronic devices without swelling issues.
Implementation Method 1
the cathode active material is a composite oxide of lithium and transition metals which has been heat-treated at 50° C. to 100° C. for 1 hour to 48 hours in a vacuum atmosphere or in an inert atmosphere
Data Source
AI summary
A cathode active material for a lithium rechargeable battery is provided. The cathode active material is used for a lithium rechargeable battery containing a cathode, an anode, and an electrolytic solution. The cathode active material is composed of 0.5% by weight or less carbonate ion (CO32−) plus bicarbonate ion (HCO3−) and 0.1% by weight or less hydroxyl ion (OH−). The swelling of lithium battery containing the cathode active material is substantially suppressed when is placed at 60° C. or more.