Secondary Battery Winding Misalignment Detection via Voltage Relaxation
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Solution Overview
Problem
Current methods for inspecting winding misalignment between positive and negative electrode sheets in secondary batteries are invasive, requiring disassembly and are not suitable for full-scale inspections, making them impractical for routine testing.
Innovation Solution
A non-destructive testing method that evaluates the coverage of the negative electrode active material layer over the positive electrode active material layer by detecting battery voltage increases during controlled charging and discharging cycles, allowing for the estimation of winding misalignment without disassembling the battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If disassembly and unwinding methods are used to measure winding misalignment, then measurement accuracy is improved, but testing time and operational complexity increase significantly
Solution Approach 1:
The patent replaces mechanical disassembly and physical unwinding operations with electrochemical charging/discharging processes. By applying electrical current to the sealed battery and measuring voltage changes during controlled charge-discharge cycles, the system determines winding misalignment without any physical opening or unwinding of the battery structure, thus eliminating time-consuming manual operations while maintaining measurement capability
Solution Approach 2:
The patent introduces voltage change as an intermediary parameter to indirectly measure winding misalignment. Instead of directly observing physical misalignment through disassembly, the system uses voltage responses during electrochemical cycles as a mediator that correlates with the degree of winding misalignment, enabling non-invasive measurement through the relationship between electrical behavior and structural alignment
2Measurement precision
If disassembly methods are used for inspection, then measurement accuracy is improved, but device complexity and operational difficulty increase
Solution Approach 1:
The patent replaces complex mechanical disassembly procedures with simple electrical connection and voltage measurement operations. The inspection process requires only connecting the battery to a power supply and measuring terminal voltages, eliminating the need for tools, disassembly skills, and careful reassembly, thereby dramatically simplifying operational requirements while maintaining measurement capability
Solution Approach 2:
The battery itself serves as the measurement system by utilizing its own electrochemical properties during normal charge-discharge cycles. The voltage changes that occur during these self-contained electrochemical processes provide the measurement signal, eliminating the need for external mechanical intervention, specialized equipment, or complex operational procedures
3Measurement precision
If sampling inspection with disassembly is used, then measurement accuracy is improved, but productivity decreases due to time consumption
Solution Approach 1:
The patent enables continuous inspection operations by using rapid electrochemical charge-discharge cycles that can be performed sequentially on multiple batteries without interruption. Each battery undergoes a brief charging phase followed by voltage measurement, then immediately proceeds to discharge and measurement, creating a continuous inspection flow that dramatically increases throughput compared to time-consuming manual disassembly methods
Solution Approach 2:
The patent skips the time-consuming intermediate steps of disassembly, unwinding, and physical measurement by rushing directly through the electrochemical charge-discharge process. The entire inspection is compressed into brief electrical cycles that can be completed in minutes per battery, allowing rapid processing of large numbers of units while maintaining accurate measurement capability
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
Enables a full inspection of winding misalignment in secondary batteries without disassembly, reducing testing time and effort, and improving the reliability of identifying misaligned products before shipment.
Implementation Method 1
a period of time has elapsed after the discharging, a voltage increase of the battery is detected
Data Source
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AI summary
A method of testing a secondary battery includes step A of charging the secondary battery to a predetermined charge voltage, step B of setting aside the secondary battery for a predetermined time (tb) after the step A, step C of discharging the secondary battery to a predetermined discharge voltage after the step B, and step D of detecting a battery voltage increase for a preset time (t2) after a predetermined time (t1) has elapsed after the step C. This method of testing a secondary battery can evaluate a measurement of how much the negative electrode active material layer covers the positive electrode active material layer based on the battery voltage increase detected in the step D.