Battery Separator Resistance Measurement Under Dynamic Pressure
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Solution Overview
Problem
Existing methods for measuring separator resistance in secondary batteries only evaluate insulating properties and do not account for the actual operating conditions, including pressure changes due to dendrite generation during charging and discharging, which affect the electrode assembly's charge/discharge characteristics.
Innovation Solution
A press type apparatus and method that measures resistance of a separator immersed in electrolyte solution by applying and controlling pressure, using a pressure control unit to vary pressure from P0 to P1 and back, with electrodes connected to a resistance measuring unit to monitor resistance changes in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the separator is measured using conventional pinching method between upper and lower jigs, then the insulating characteristics of the separator itself can be measured, but the resistance characteristics reflecting the actual use conditions of the secondary battery cannot be measured
Solution Approach 1:
The separator is impregnated with electrolyte solution before measurement, and the electrode assembly is assembled in advance within the battery case. This preliminary preparation ensures that the separator is in the same state as during actual battery operation, allowing resistance characteristics under real use conditions to be accurately measured.
Solution Approach 2:
The invention creates a simplified model of the actual battery structure by assembling the electrode assembly within the battery case, placing the separator in its actual operating environment with electrolyte impregnation and electrode contacts, rather than measuring the separator in isolation.
2Device complexity
If the separator is measured without considering pressure changes, then the measurement process is simple, but the charge/discharge characteristics of the electrode assembly cannot be reflected
Solution Approach 1:
The invention applies dynamic pressure changes during measurement, increasing pressure from P0 to P1 and then decreasing back to P0, to simulate the volume changes and pressure variations that occur during battery charging and discharging. This dynamic approach captures the separator's resistance characteristics under varying operational conditions.
Solution Approach 2:
The invention changes the pressure parameter during measurement to reflect actual battery operation conditions. By varying pressure from P0 (initial state) to P1 (pressurized state during charging/discharging) and back, the measurement captures how resistance characteristics change with pressure, thereby reflecting charge/discharge behavior.
3Device complexity
If the separator is measured in isolation without electrode assembly, then the measurement setup is simple, but the actual operating state of the secondary battery cannot be evaluated
Solution Approach 1:
The invention creates a simplified model of the actual battery structure by assembling the electrode assembly within the battery case, placing the separator in its actual operating environment with electrolyte impregnation and electrode contacts, rather than measuring the separator in isolation.
Solution Approach 2:
The measurement setup serves multiple functions: it measures the separator's resistance, evaluates the electrode assembly's charge/discharge characteristics, and simulates actual battery operating conditions all within a single integrated system, rather than requiring separate tests for each aspect.
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 real-time measurement of resistance reflecting the actual operating state of secondary batteries, allowing for the detection of defects by comparing resistance values at different pressures, thus ensuring the separator's integrity under varying conditions.
Implementation Method 1
a resistance measuring unit configured to be connected to the first and second electrodes of the electrode unit, respectively, to thereby measure a resistance of the separator
Implementation Method 2
a pressure control unit configured to control a pressure applied to the separator through a height adjustment of at least one of the receiving portion and the molding unit
Data Source
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AI summary
The present invention relates to a device and method which can measure, in real time, the resistance, depending on pressure changes, of a separator that is immersed in an electrolyte, and enables analysis of the resistance properties of a separator reflecting the real operating state of a secondary battery.