Ambulatory Infusion Device Battery Testing and Alerting
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Solution Overview
Problem
Ambulatory infusion devices face challenges in ensuring safe and reliable operation due to unsuitable energy storage, as users may unknowingly use batteries that are not suited for the device, leading to unexpected voltage drops and potential severe adverse effects, especially when traveling or using foreign batteries.
Innovation Solution
The device includes a testing unit that measures and evaluates the off-circuit voltage and internal resistance of the energy storage, triggering an alert if the storage is not capable of powering the device, allowing for safe operation and user notification, and varying the testing frequency and stress based on the storage's condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If widely available batteries (AA or AAA cells) are used to power the device, then the device can be powered by easily obtainable energy storage, but the device may experience unexpected voltage drops and terminate operation without alerting the user due to unsuitable battery characteristics
Solution Approach 1:
The device performs preliminary testing of the battery before actual use by measuring open-circuit voltage and internal resistance. This preliminary characterization allows the device to evaluate whether the battery is suitable for powering the infusion pump, preventing unreliable operation before it occurs.
Solution Approach 2:
The device continuously monitors battery parameters during operation and provides feedback to the user through alerts when battery characteristics indicate potential failure. This feedback mechanism allows the user to replace the battery before unexpected termination occurs.
2Device complexity
If conventional battery testing methods are used (repeated connection to test load and voltage measurement), then the testing procedure is simple, but the device may not detect steep voltage drops that occur during operation, leading to unalerted termination
Solution Approach 1:
Instead of only measuring voltage under load, the device measures both open-circuit voltage and internal resistance parameters. By analyzing the relationship between these parameters and the expected voltage drop characteristics, the device can predict when a battery will cause unexpected termination, even with simple testing procedures.
3Reliability
If the device carries out frequent battery tests to ensure safe operation, then the reliability of operation is improved, but the device complexity and power consumption increase
Solution Approach 1:
The device performs a limited set of essential battery tests (open-circuit voltage and internal resistance measurements) rather than comprehensive continuous monitoring. This partial testing approach provides sufficient reliability for safe operation while keeping the testing mechanism simple and power consumption low.
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 solution enables safe and reliable operation of ambulatory infusion devices by ensuring that only capable energy storage is used, reducing unnecessary battery replacement and providing timely alerts to users, thus preventing adverse effects.
Implementation Method 1
The testing unit (510) includes a measurement unit for determining the off-circuit voltage and the internal resistance of the energy storage
Implementation Method 2
The terminal voltage is generally smaller as compared to the off-circuit voltage because of a voltage over the internal resistor. This voltage drop is defined according to Ohm's law by the internal resistance and the current that is drawn
Data Source
AI summary
Disclosed are ambulatory infusion devices, including: (a) user-replaceable energy storage (100) for storing electrical energy required for powering the device (10), the energy storage having an off-circuit voltage, and an internal resistance, (b)a dosing unit with an electrically powered actuator and an electronic controller, the controller controlling operation of the actuator, (c) a testing unit (110), the testing unit (100) including a measurement unit for determining the off-circuit voltage and the internal resistance of the energy storage (100), the testing unit being designed to carry out tests during operation of the device, a test including • determining the off-circuit voltage and the internal resistance, • evaluating the off-current voltage and the internal resistance, thus determining if the energy storage (100) is capable for further powering the device (10), (d) an alerting unit, the alerting unit being coupled to the testing unit (110) to be activated by the testing unit (110) if a test indicates a lacking capability of the energy storage (100) for further powering the device (10). Disclosed are further corresponding methods for testing an energy storage of an ambulatory infusion device.