Electrochemical Cell Screening via Voltage Transient Analysis
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Solution Overview
Problem
Existing methods for manufacturing electrochemical cells for implantable medical devices are inefficient in detecting failure mechanisms, particularly due to contamination, which can lead to unsuitable battery performance and require destructive testing for validation.
Innovation Solution
A non-destructive method involving the measurement of open circuit voltage over time to identify failure criteria, such as first-order discontinuities in the voltage versus time function, using derivatives and filtering techniques to detect potential contaminants and ensure battery reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional manufacturing methods are used for electrochemical cells, then production can proceed with standard processes, but failure mechanisms such as contamination cannot be detected without destructive testing
Solution Approach 1:
The patent applies preliminary action by measuring the open circuit voltage of the electrochemical cell immediately after activation, before the cell is sealed or integrated into a device. This early measurement captures the voltage transient caused by contamination or other failure mechanisms before they can cause actual damage, enabling non-destructive detection of defects that would otherwise require destructive testing to identify.
Solution Approach 2:
The patent replaces mechanical/destructive testing methods with an electrical measurement approach. Instead of using physical inspection or destructive disassembly to detect contamination and failure mechanisms, the invention uses voltage measurements and derivative analysis to identify defects, thereby eliminating the need to destroy the cell for validation.
2Measurement precision
If extended burn-in periods are used to allow cells to reach thermal equilibrium, then measurement accuracy improves, but manufacturing time and productivity decrease
Solution Approach 1:
The patent applies partial action by measuring the voltage transient during the initial phase of thermal equilibrium establishment, rather than waiting for complete thermal stabilization. The method captures the essential information about contamination and failure mechanisms in the voltage changes that occur during the first portion of the burn-in period, achieving sufficient measurement precision without requiring the full extended time traditionally needed for thermal equilibrium.
Solution Approach 2:
The voltage measurement serves multiple functions simultaneously: it monitors thermal equilibrium progress, detects contamination through voltage transients, validates cell performance, and identifies failure mechanisms. This multi-functionality allows the measurement to be performed during the burn-in process itself rather than requiring a separate dedicated measurement phase, thereby maintaining productivity while achieving measurement precision.
3Reliability
If non-destructive screening methods are implemented, then defective cells can be identified before integration, but additional measurement and analysis steps are required
Solution Approach 1:
The electrochemical cell performs self-diagnosis through its own voltage response to activation. The cell's natural voltage transient during the transition to thermal equilibrium reveals information about its internal state, including contamination and potential failure mechanisms. This self-service approach eliminates the need for external complex testing equipment or procedures, as the cell itself provides the diagnostic information through its operational characteristics.
Solution Approach 2:
The method uses feedback by continuously monitoring the open circuit voltage and comparing it against expected behavior patterns. The voltage measurements provide real-time feedback about the cell's health status, and the derivative analysis compares the rate of change against thresholds to automatically identify defective cells. This feedback mechanism enables automated screening decisions without requiring complex manual analysis procedures.
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 effectively screens for battery failure mechanisms, reducing the risk of contamination and improving battery performance by identifying defective cells before integration into medical devices, thereby enhancing the reliability and longevity of electrochemical cells.
Implementation Method 1
activating an electrochemical cell... the open circuit voltage of the cell is measured
Data Source
AI summary
A method of screening a battery for failure mechanisms is provided. The method may include activating an electrochemical cell. Within 5 minutes to two hours of activating the cell, the open circuit voltage of the cell is measured over a period of time to determine a voltage versus time function. The cell is then screened for the presence of a failure mechanism by checking the voltage versus time function for a failure criteria.