Power Storage Device Internal Short Circuit Inspection Method
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Solution Overview
Problem
Existing methods for inspecting internal short circuits in power storage devices, such as lithium-ion batteries, are either time-consuming due to voltage measurement inaccuracies or require longer observation periods, and there is a need for a more rapid and accurate technique to determine internal short circuits during the manufacturing process.
Innovation Solution
A power storage device inspecting method that involves connecting external probes to form a closed circuit, detecting external resistance, applying an initial output voltage, and adjusting the output voltage based on a virtual external resistance to rapidly determine internal short circuits by monitoring changes in device current, allowing for quicker convergence and more accurate assessments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage measurement is performed using conventional methods with external probes, then the measurement process is simple, but the measurement precision is poor due to contact resistance
Solution Approach 1:
The patent replaces voltage measurement (which is affected by contact resistance) with current measurement. The external power supply measures device current instead of voltage, eliminating the impact of contact resistance between probes and terminals. This substitution of measurement method resolves the technical contradiction by achieving high precision without requiring complex compensation mechanisms.
2Reliability
If left-alone time is extended to achieve significant voltage drop for short circuit detection, then the reliability of detection improves, but the productivity decreases
Solution Approach 1:
The patent changes the measurement parameter from voltage to current. By measuring device current during self-discharge instead of waiting for significant voltage drop, the inspection can be completed in much shorter time. The external power supply continuously measures current, and short circuits are detected based on current characteristics, eliminating the need for extended observation periods and thereby improving productivity while maintaining detection reliability.
3Ease of operation
If voltage measurement is performed with external probes, then the ease of operation is good, but the measurement precision deteriorates due to contact resistance
Solution Approach 1:
The patent substitutes voltage measurement with current measurement using an external power supply. The power supply connects to device terminals and measures current flow during self-discharge. This approach maintains operational simplicity while eliminating contact resistance errors, as current measurement is not affected by probe contact quality unlike voltage measurement.
4Productivity
If conventional voltage-based inspection method is used, then the device complexity is low, but the productivity is reduced due to long inspection time
Solution Approach 1:
The external power supply serves multiple functions: it charges the power storage device initially, maintains voltage during self-discharge, and measures device current continuously. This multi-functionality enables rapid current-based short circuit detection without requiring separate specialized equipment, thereby improving productivity while keeping the inspection system relatively simple.
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 enables rapid and accurate determination of internal short circuits, reducing the time required for manufacturing and improving the reliability of power storage device inspection by stabilizing the device current and minimizing the impact of external resistance variations.
Implementation Method 1
detecting an external resistance Re which is generated in an external circuit outside the power storage device in the closed circuit
Data Source
AI summary
A power storage device inspecting method of inspecting a power storage device for an internal short circuit that includes: detecting an external resistance Re which is generated in an external circuit in a state in which probes of an external power supply are connected to external terminals of the power storage device; applying an initial output voltage VS(0) with which an initial device current IB(0) of a device current IB(t) is zero; applying an output voltage VS(t) from the external power supply to the power storage device; and determining an internal short circuit of the power storage device based on a change with time of the device current IB(t) or a stabilized device current IBs of the power storage device.