Lithium Secondary Battery Activation With Oxygen Degassing
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Solution Overview
Problem
Lithium secondary batteries with positive electrode active materials or additives that generate a large amount of oxygen during charging face challenges in forming a stable SEI film due to oxygen reacting with the electrolyte, leading to performance degradation and reduced lifespan.
Innovation Solution
A lithium secondary battery activation method involving a primary charging process, a degassing process to remove internal oxygen, an aging process, and a secondary charging process, where the degassing process is performed between primary charging and aging to minimize oxygen reaction with the electrolyte and facilitate stable SEI film formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a primary charging process is performed on a secondary battery with positive electrode active material or additive that generates oxygen, then the battery achieves initial charge, but oxygen reacts with electrolyte and SEI film, further increasing gas generation and deteriorating film performance
Solution Approach 1:
The patent extracts and removes the harmful oxygen gas generated during primary charging through a dedicated degassing process performed between primary charging and aging, preventing oxygen from reacting with electrolyte and SEI film, thereby eliminating the harmful effect while preserving the charging function
Solution Approach 2:
The patent performs a preliminary degassing action before the aging process to remove oxygen that was generated during primary charging, preventing subsequent harmful reactions between oxygen and the SEI film or electrolyte, thus protecting the film formation process
2Reliability
If conventional activation method (primary charging followed by aging) is applied to batteries generating large oxygen amounts, then aging process stabilizes battery, but oxygen reaction with electrolyte and film formation is hindered, reducing film performance
Solution Approach 1:
The patent extracts harmful oxygen gas through a degassing process performed between primary charging and aging, removing the obstacle that would otherwise interfere with film formation and electrolyte stability during the aging process
Solution Approach 2:
The patent performs preliminary degassing before aging to remove oxygen that would otherwise react with the electrolyte and hinder proper SEI film formation during the aging process, ensuring high-quality film formation while maintaining battery stability
3Quantity of substance
If irreversible additives with high irreversible capacity are used to increase battery capacity, then energy density improves, but structural instability increases and oxygen gas generation increases
Solution Approach 1:
The patent converts the harmful effect of oxygen generation from high-capacity irreversible additives into a manageable process by implementing a controlled degassing protocol that removes oxygen during activation, allowing the use of high-capacity additives like Li6CoO4 without suffering from their structural instability and gas generation problems
Solution Approach 2:
The patent changes the processing parameters by introducing a specific degassing step between primary charging and aging, transforming the problematic oxygen generation characteristic of high-capacity additives into a controlled process that eliminates gas while preserving the high capacity benefits
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 effectively stabilizes SEI film formation, enhancing the battery's capacity and lifespan by immediately removing internal oxygen, thus improving electrical performance and safety.
Implementation Method 1
a degassing process of discharging an internal gas containing oxygen to the outside of the secondary battery or moving it to a gas pocket
Data Source
AI summary
An activation method for a lithium secondary battery includes: a primary charging process charging a lithium secondary battery; a first degassing process discharging an internal gas containing oxygen to an outside of the lithium secondary battery or moving the internal gas containing oxygen to a gas pocket part after the primary charging process; an aging process aging the lithium secondary battery after the first degassing process; and a second degassing process removing gas from the aged lithium secondary battery.