Lithium Secondary Battery Activation with Staged SOC Charging
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Solution Overview
Problem
Existing secondary battery manufacturing processes are time-consuming and can degrade battery quality due to inefficient activation processes, particularly through excessive side reactions and gas buildup.
Innovation Solution
A method involving controlled charging and discharging to form a solid electrolyte interphase (SEI) film, followed by formation-charging within a specific state of charge (SOC) range, aging, and shipment charging to minimize side reactions and gas release, all conducted under controlled temperature and pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional activation process is used, then battery becomes usable, but activation time is excessive and battery quality degrades due to side reactions and gas buildup
Solution Approach 1:
The activation process is divided into multiple distinct stages: initial charging to form SEI film, formation charging to 30-60% SOC, aging process, discharging, and shipment charging to 20-30% SOC. Each stage serves a specific function, allowing the process to be optimized for both speed and quality without compromising either aspect.
Solution Approach 2:
The patent optimizes specific parameters including SOC ranges (30-60% for formation charging, 20-30% for shipment charging), temperature conditions (30-60°C for formation charging), and the number of SEI film formation cycles (3 times or less). These parameter optimizations enable reduced activation time while maintaining or improving battery quality by minimizing side reactions and gas generation.
2Stability of the object's composition
If repeated charging and discharging is performed to form SEI film, then battery structure is stabilized, but process time increases
Solution Approach 1:
The patent performs SEI film formation by repeating charging to 20% SOC and discharging to 0% SOC only 3 times or less, which is fewer repetitions than conventional methods. This partial action is sufficient to form an adequate SEI film for structural stabilization while significantly reducing the time required compared to excessive repetition.
Solution Approach 2:
The SEI film formation process is conducted as a preliminary step before formation charging and aging. By preparing the SEI film in advance with controlled repetitions, the subsequent activation steps can proceed more efficiently, and the battery structure is pre-stabilized for better overall performance.
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
Reduces activation time and enhances battery quality by forming a uniform SEI film, improving electrolyte impregnation and reducing side reactions, thereby enhancing the overall performance and efficiency of the secondary battery.
Implementation Method 1
forming a solid electrolyte interphase (SEI) film by repeatedly charging and discharging the secondary battery cell
Implementation Method 2
formation-charging an assembled secondary battery cell so that a state of charge (SOC) of the assembled secondary battery cell is about 30% or more and about 60% or less
Data Source
AI summary
The present disclosure relates to a manufacturing method of a secondary battery. A manufacturing method of a secondary battery according to one or more embodiments includes formation-charging an assembled secondary battery cell so that SOC of the assembled secondary battery cell is about 30% or more and about 60% or less, aging the formation-charged secondary battery cell, discharging the secondary battery cell in which the aging is completed, and shipment charging the secondary battery cell so that the SOC of the discharged secondary battery cell becomes about 20% or more and about 30% or less.