Lithium Ion Battery Defect Detection via Pressurized Aging
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Solution Overview
Problem
Current methods for checking defects in lithium ion secondary batteries, particularly inner fine short circuit defects, are inadequate during the aging process, leading to abnormal open circuit voltage (OCV) reductions and frequent defect emergence in real-world applications.
Innovation Solution
A method involving charging and degassing the battery, followed by pressurizing and aging it under a designated pressure (0.2-5 kg/cm2) and temperature (45° C to 60° C) to re-measure OCVs and internal resistances (IRs), allowing for improved defect discrimination by comparing pre and post-aging measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional aging process is used without applied pressure, then the manufacturing process is simple, but inner fine short circuit defects cannot be detected and OCV abnormally reduces
Solution Approach 1:
The patent applies pressure (0.2-5 kg/cm²) as a physical parameter during the aging process to induce mechanical stress on internal particles. This parameter change enables the detection of fine short circuit defects that cannot be detected under conventional atmospheric pressure conditions, directly improving measurement precision while adding only a single controllable parameter to the process.
2Measurement precision
If aging time is increased to improve defect detection, then defect discrimination improves, but manufacturing time and productivity decrease
Solution Approach 1:
The patent applies pressure during the aging process to accelerate the mechanical movement of particles toward electrode contacts. This preliminary mechanical action forces particles that would otherwise require extended time to naturally migrate, thereby achieving adequate defect detection in a shorter aging period and improving overall manufacturing productivity.
3Reliability
If pressure is applied during aging, then fine short circuit defects are detected and OCV stability improves, but additional equipment and process control are required
Solution Approach 1:
The patent employs a pressure control system (pneumatic or hydraulic) to apply controlled pressure (0.2-5 kg/cm²) during aging. This approach enables reliable detection of fine short circuit defects and ensures OCV stability by forcing particles into contact with electrodes, while using standardized pneumatic/hydraulic technology to minimize additional equipment 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
This method enhances the detection of short circuit defects caused by high-resistance protruding or growth-type particles, reduces aging time, and improves cell stability and commercial value by minimizing defect outflow.
Implementation Method 1
pressurizing and aging the lithium ion secondary battery by aging the lithium ion secondary battery in a state in which a pressure of a designated magnitude or more is applied to the lithium ion secondary battery
Data Source
AI summary
A method for checking defects in a lithium ion secondary battery includes primarily charging and degassing the lithium ion secondary battery after manufacture of the secondary battery, secondarily charging and discharging the secondary battery and then measuring one or more of OCVs and IRs of lithium ion secondary battery cells; pressurizing and aging the secondary battery by aging the secondary battery in a state in which a pressure of a designated magnitude or more is applied to the secondary battery, and checking whether or not the secondary battery cells are defective by re-measuring the one or more of OCVs and IRs of the secondary battery cells and then comparing the re-measured one or more of the OCVs and the IRs to the previously measured one or more of the OCVs and the IRs.